Sample records for environmentally relevant salinity
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USDA-ARS?s Scientific Manuscript database
Soil salinity is a major threat to sustainable agriculture, especially in arid and semi-arid regions. Updated and accurate inventories of salinity in agronomically and environmentally relevant ranges (i.e., <20 dS/m, when salinity is measured as electrical conductivity of the saturation extract, ECe...
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USDA-ARS?s Scientific Manuscript database
Soil salinity is recognized worldwide as a major threat to agriculture, particularly in arid and semi-arid regions. Farmers and decision makers need updated and accurate maps of salinity in agronomically and environmentally relevant ranges (i.e., <20 dS m/1, when salinity is measured as electrical...
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Hintz, William D; Relyea, Rick A
2017-04-01
The use of road deicing salts in regions that experience cold winters is increasing the salinity of freshwater ecosystems, which threatens freshwater resources. Yet, the impacts of environmentally relevant road salt concentrations on freshwater organisms are not well understood, particularly in stream ecosystems where salinization is most severe. We tested the impacts of deicing salts-sodium chloride (NaCl), magnesium chloride (MgCl 2 ), and calcium chloride (CaCl 2 )-on the growth and development of newly hatched rainbow trout (Oncorhynchus mykiss). We exposed rainbow trout to a wide range of environmentally relevant chloride concentrations (25, 230, 860, 1500, and 3000 mg Cl - L -1 ) over an ecologically relevant time period (25 d). We found that the deicing salts studied had distinct effects. MgCl 2 did not affect rainbow trout growth at any concentration. NaCl had no effects at the lowest three concentrations, but rainbow trout length was reduced by 9% and mass by 27% at 3000 mg Cl - L -1 . CaCl 2 affected rainbow trout growth at 860 mg Cl - L -1 (5% reduced length; 16% reduced mass) and these effects became larger at higher concentrations (11% reduced length; 31% reduced mass). None of the deicing salts affected rainbow trout development. At sub-lethal and environmentally relevant concentrations, our results do not support the paradigm that MgCl 2 is the most toxic deicing salt to fish, perhaps due to hydration effects on the Mg 2+ cation. Our results do suggest different pathways for lethal and sub-lethal effects of road salts. Scaled to the population level, the reduced growth caused by NaCl and CaCl 2 at critical early-life stages has the potential to negatively affect salmonid recruitment and population dynamics. Our findings have implications for environmental policy and management strategies that aim to reduce the impacts of salinization on freshwater organisms. Copyright © 2017 Elsevier Ltd. All rights reserved.
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THE EFFECT OF SALINITY ON RATES OF ELEMENTAL MERCURY AIR/WATER EXCHANGE
The U.S. EPA laboratory in Athens, Georgia i spursuing the goal of developing a model for describing toxicant vapor phase air/water exchange under all relevant environmental conditions. To date, the two-layer exchange model (suitable for low wind speed conditions) has been modif...
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Bacterial diversity patterns of the intertidal biofilm in urban beaches of Río de la Plata.
Piccini, C; García-Alonso, J
2015-02-28
Intertidal benthic ecosystems in estuaries are productive sites where microbial processes play critical roles in nutrients mineralization, primary production and trophic web. In this groundwork study we analyzed the bacterial community of intertidal biofilms from Río de la Plata beaches with different anthropogenic impacts. Several environmental parameters were measured and bacterial assemblages were analyzed by 16S-rDNA pyrosequencing. The average OTU found per sample was 527.3±122.5, showing similar richness and diversity among them. However, sites having the highest and lowest salinity displayed higher bacterial diversity. Assemblages from a site nearby an oil refinery, showing the lowest salinity and oxygen concentration, were clearly distinct from the rest. The weight of this splitting relied on OTUs belonging to Thauera, known by its ability to metabolize aromatic compounds. Our results suggest that intertidal bacterial assemblages would be structured by major estuarine variables such as salinity, and that anthropogenic-induced environmental parameters might also be relevant. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Leal, Laura C; Meiado, Marcos V; Lopes, Ariadna V; Leal, Inara R
2013-09-01
Life history traits are considered key indicators of plant invasibility. Among them, the germination behavior of seeds is of major relevance because it is influenced by environmental factors of invaded ecosystem. Here, we investigated how seed traits and seed tolerance to environmental factors on seed germination of Calotropis procera vary depending on the invaded ecosystems in northeastern Brazil. We have tested seeds from two vegetation types - Caatinga and Restinga - to different levels of light intensity, salinity, and water stress. Previous to those experiments, seed-set and morphometric analysis were carried out for both studied populations. We have observed a higher seed-set in Caatinga. Seeds produced in this ecosystem had lower seed moisture content. Seeds from Restinga showed lower germination time when light intensity decreased. We observed a reduction in both the germinability and the synchronization index with decreasing osmotic potential and increasing salinity. Nevertheless, both populations exhibited changes in photoblastism when seeds were submitted to water and saline stress. In conclusion, C. procera seeds are tolerant to environmental factors assessed. That characteristic ensures the colonization success and wide distribution of this plant species in the studied ecosystems.
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NASA Astrophysics Data System (ADS)
Ma, Ligang; Ma, Fenglan; Li, Jiadan; Gu, Qing; Yang, Shengtian; Ding, Jianli
2017-04-01
Land degradation, specifically soil salinization has rendered large areas of China west sterile and unproductive while diminishing the productivity of adjacent lands and other areas where salting is less severe. Up to now despite decades of research in soil mapping, few accurate and up-to-date information on the spatial extent and variability of soil salinity are available for large geographic regions. This study explores the po-tentials of assessing soil salinity via linear and random forest modeling of remote sensing based environmental factors and indirect indicators. A case study is presented for the arid oases of Tarim and Junggar Basin, Xinjiang, China using time series land surface temperature (LST), evapotranspiration (ET), TRMM precipitation (TRM), DEM product and vegetation indexes as well as their second order products. In par-ticular, the location of the oasis, the best feature sets, different salinity degrees and modeling approaches were fully examined. All constructed models were evaluated for their fit to the whole data set and their performance in a leave-one-field-out spatial cross-validation. In addition, the Kruskal-Wallis rank test was adopted for the statis-tical comparison of different models. Overall, the random forest model outperformed the linear model for the two basins, all salinity degrees and datasets. As for feature set, LST and ET were consistently identified to be the most important factors for two ba-sins while the contribution of vegetation indexes vary with location. What's more, models performances are promising for the salinity ranges that are most relevant to agricultural productivity.
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Hall, Matthew D; Vettiger, Andrea; Ebert, Dieter
2013-04-01
Interactions between environmental stressors play an important role in shaping the health of an organism. This is particularly true in terms of the prevalence and severity of infectious disease, as stressors in combination will not always act to simply decrease the immune function of a host, but may instead interact to compound or even oppose the influence of parasitism on the health of an organism. Here, we explore the impact of environmental stress on host-parasite interactions using the water flea Daphnia magna and it is obligate parasite Pasteuria ramosa. Utilising an ecologically relevant stressor, we focus on the combined effect of salinity and P. ramosa on the fecundity and survival of the host, as well as on patterns of infectivity and the proliferation of the parasite. We show that in the absence of the parasite, host fecundity and survival was highest in the low salinity treatments. Once a parasite was introduced into the environment, however, salinity and parasitism acted antagonistically to influence both host survival and fecundity, and these patterns of disease were unrelated to infection rates or parasite spore loads. By summarising the form of interactions found in the broader Daphnia literature, we highlight how the combined effect of stress and parasitism will vary with the type of stressor, the trait used to describe the health of Daphnia and the host-parasite combination under observation. Our results highlight how the context-dependent nature of interactions between stress and parasitism inevitably complicates the link between environmental factors and the prevalence and severity of disease.
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Stable near-surface ocean salinity stratifications due to evaporation observed during STRASSE
NASA Astrophysics Data System (ADS)
Asher, William E.; Jessup, Andrew T.; Clark, Dan
2014-05-01
Under conditions with a large solar flux and low wind speed, a stably stratified warm layer forms at the ocean surface. Evaporation can then lead to an increase in salinity in the warm layer. A large temperature gradient will decrease density enough to counter the density increase caused by the salinity increase, forming a stable positive salinity anomaly at the surface. If these positive salinity anomalies are large in terms of the change in salinity from surface to the base of the gradient, if their areal coverage is a significant fraction of the satellite footprint, and if they persist long enough to be in the satellite field of view, they could be relevant for calibration and validation of L-band microwave salinity measurements. A towed, surface-following profiler was deployed from the N/O Thalassa during the Subtropical Atlantic Surface Salinity Experiment (STRASSE). The profiler measured temperature and conductivity in the surface ocean at depths of 10, 50, and 100 cm. The measurements show that positive salinity anomalies are common at the ocean surface for wind speeds less than 4 m s-1 when the average daily insolation is >300 W m-2 and the sea-to-air latent heat flux is greater than zero. A semiempirical model predicts the observed dependence of measured anomalies on environmental conditions. However, the model results and the field data suggest that these ocean surface salinity anomalies are not large enough in terms of the salinity difference to significantly affect microwave radiometric measurements of salinity.
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Using growth-based methods to determine direct effects of salinity on soil microbial communities
NASA Astrophysics Data System (ADS)
Rath, Kristin; Rousk, Johannes
2015-04-01
Soil salinization is a widespread agricultural problem and increasing salt concentrations in soils have been found to be correlated with decreased microbial activity. A central challenge in microbial ecology is to link environmental factors, such as salinity, to responses in the soil microbial community. That is, it can be difficult to distinguish direct from indirect effects. In order to determine direct salinity effects on the community we employed the ecotoxicological concept of Pollution-Induced Community Tolerance (PICT). This concept is built on the assumption that if salinity had an ecologically relevant effect on the community, it should have selected for more tolerant species and strains, resulting in an overall higher community tolerance to salt in communities from saline soils. Growth-based measures, such as the 3H-leucine incorporation into bacterial protein , provide sensitive tools to estimate community tolerance. They can also provide high temporal resolution in tracking changes in tolerance over time. In our study we used growth-based methods to investigate: i) at what levels of salt exposure and over which time scales salt tolerance can be induced in a non-saline soil, and (ii) if communities from high salinity sites have higher tolerance to salt exposure along natural salinity gradients. In the first part of the study, we exposed a non-saline soil to a range of salinities and monitored the development of community tolerance over time. We found that community tolerance to intermediate salinities up to around 30 mg NaCl per g soil can be induced at relatively short time scales of a few days, providing evidence that microbial communities can adapt rapidly to changes in environmental conditions. In the second part of the study we used soil samples originating from natural salinity gradients encompassing a wide range of salinity levels, with electrical conductivities ranging from 0.1 dS/m to >10 dS/m. We assessed community tolerance to salt by measuring the bacterial growth response to added NaCl in a soil suspension. The bacterial community tolerance to salt increased along the salt gradients with higher in situ soil salinity. In samples from the low-saline end of the gradient, bacterial growth rates in the soil suspension showed a clear concentration-response relationship to NaCl resulting in inhibition curves. This relationship gradually changed toward higher salt concentrations. In soil samples from high salinity sites, bacterial growth was no longer inhibited by adding high concentrations of NaCl to the bacterial soil suspension. In fact, adding NaCl even promoted bacterial growth rates. These results show that salinity played an ecologically significant role in shaping communities at the highly saline end of the gradients and provide evidence for a direct salt effect on the microbial community
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Tunnah, Louise; MacKellar, Sara R C; Barnett, David A; MacCormack, Tyson J; Stehfest, Kilian M; Morash, Andrea J; Semmens, Jayson M; Currie, Suzanne
2016-07-01
Shark nurseries are susceptible to environmental fluctuations in salinity because of their shallow, coastal nature; however, the physiological impacts on resident elasmobranchs are largely unknown. Gummy sharks (Mustelus antarcticus) and school sharks (Galeorhinus galeus) use the same Tasmanian estuary as a nursery ground; however, each species has distinct distribution patterns that are coincident with changes in local environmental conditions, such as increases in salinity. We hypothesized that these differences were directly related to differential physiological tolerances to high salinity. To test this hypothesis, we exposed wild, juvenile school and gummy sharks to an environmentally relevant hypersaline (120% SW) event for 48 h. Metabolic rate decreased 20-35% in both species, and gill Na(+)/K(+)-ATPase activity was maintained in gummy sharks but decreased 37% in school sharks. We measured plasma ions (Na(+), K(+), Cl(-)) and osmolytes [urea and trimethylamine oxide (TMAO)], and observed a 33% increase in plasma Na(+) in gummy sharks with hyperosmotic exposure, while school sharks displayed a typical ureosmotic increase in plasma urea (∼20%). With elevated salinity, gill TMAO concentration increased by 42% in school sharks and by 30% in gummy sharks. Indicators of cellular stress (heat shock proteins HSP70, 90 and 110, and ubiquitin) significantly increased in gill and white muscle in both a species- and a tissue-specific manner. Overall, gummy sharks exhibited greater osmotic perturbation and ionic dysregulation and a larger cellular stress response compared with school sharks. Our findings provide physiological correlates to the observed distribution and movement of these shark species in their critical nursery grounds. © 2016. Published by The Company of Biologists Ltd.
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Fietz, Katharina; Rye Hintze, Christian Olaf; Skovrind, Mikkel; Kjærgaard Nielsen, Tue; Limborg, Morten T; Krag, Marcus A; Palsbøll, Per J; Hestbjerg Hansen, Lars; Rask Møller, Peter; Gilbert, M Thomas P
2018-05-02
Deciphering the mechanisms governing population genetic divergence and local adaptation across heterogeneous environments is a central theme in marine ecology and conservation. While population divergence and ecological adaptive potential are classically viewed at the genetic level, it has recently been argued that their microbiomes may also contribute to population genetic divergence. We explored whether this might be plausible along the well-described environmental gradient of the Baltic Sea in two species of sand lance (Ammodytes tobianus and Hyperoplus lanceolatus). Specifically, we assessed both their population genetic and gut microbial composition variation and investigated not only which environmental parameters correlate with the observed variation, but whether host genome also correlates with microbiome variation. We found a clear genetic structure separating the high-salinity North Sea from the low-salinity Baltic Sea sand lances. The observed genetic divergence was not simply a function of isolation by distance, but correlated with environmental parameters, such as salinity, sea surface temperature, and, in the case of A. tobianus, possibly water microbiota. Furthermore, we detected two distinct genetic groups in Baltic A. tobianus that might represent sympatric spawning types. Investigation of possible drivers of gut microbiome composition variation revealed that host species identity was significantly correlated with the microbial community composition of the gut. A potential influence of host genetic factors on gut microbiome composition was further confirmed by the results of a constrained analysis of principal coordinates. The host genetic component was among the parameters that best explain observed variation in gut microbiome composition. Our findings have relevance for the population structure of two commercial species but also provide insights into potentially relevant genomic and microbial factors with regards to sand lance adaptation across the North Sea-Baltic Sea environmental gradient. Furthermore, our findings support the hypothesis that host genetics may play a role in regulating the gut microbiome at both the interspecific and intraspecific levels. As sequencing costs continue to drop, we anticipate that future studies that include full genome and microbiome sequencing will be able to explore the full relationship and its potential adaptive implications for these species.
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Federal Register 2010, 2011, 2012, 2013, 2014
2012-06-05
... Valley Warm Springs Management Plan/Environmental Impact Statement, Death Valley National Park, Inyo... an Environmental Impact Statement for the Saline Valley Warm Springs Management Plan, Death Valley... analysis process for the Saline Valley Warm Springs Management Plan for Death Valley [[Page 33238...
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Salinity Adaptation and the Contribution of Parental Environmental Effects in Medicago truncatula
Moriuchi, Ken S.; Friesen, Maren L.; Cordeiro, Matilde A.; Badri, Mounawer; Vu, Wendy T.; Main, Bradley J.; Aouani, Mohamed Elarbi; Nuzhdin, Sergey V.; Strauss, Sharon Y.; von Wettberg, Eric J. B.
2016-01-01
High soil salinity negatively influences plant growth and yield. Some taxa have evolved mechanisms for avoiding or tolerating elevated soil salinity, which can be modulated by the environment experienced by parents or offspring. We tested the contribution of the parental and offspring environments on salinity adaptation and their potential underlying mechanisms. In a two-generation greenhouse experiment, we factorially manipulated salinity concentrations for genotypes of Medicago truncatula that were originally collected from natural populations that differed in soil salinity. To compare population level adaptation to soil salinity and to test the potential mechanisms involved we measured two aspects of plant performance, reproduction and vegetative biomass, and phenological and physiological traits associated with salinity avoidance and tolerance. Saline-origin populations had greater biomass and reproduction under saline conditions than non-saline populations, consistent with local adaptation to saline soils. Additionally, parental environmental exposure to salt increased this difference in performance. In terms of environmental effects on mechanisms of salinity adaptation, parental exposure to salt spurred phenological differences that facilitated salt avoidance, while offspring exposure to salt resulted in traits associated with greater salt tolerance. Non-saline origin populations expressed traits associated with greater growth in the absence of salt while, for saline adapted populations, the ability to maintain greater performance in saline environments was also associated with lower growth potential in the absence of salt. Plastic responses induced by parental and offspring environments in phenology, leaf traits, and gas exchange contribute to salinity adaptation in M. truncatula. The ability of plants to tolerate environmental stress, such as high soil salinity, is likely modulated by a combination of parental effects and within-generation phenotypic plasticity, which are likely to vary in populations from contrasting environments. PMID:26943813
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NASA Astrophysics Data System (ADS)
Rath, Kristin; Fierer, Noah; Rousk, Johannes
2017-04-01
Our knowledge of the dynamics structuring microbial communities and the consequences this has for soil functions is rudimentary. In particular, predictions of the response of microbial communities to environmental change and the implications for associated ecosystem processes remain elusive. Understanding how environmental factors structure microbial communities and regulate the functions they perform is key to a mechanistic understanding of how biogeochemical cycles respond to environmental change. Soil salinization is an agricultural problem in many parts of the world. The activity of soil microorganisms is reduced in saline soils compared to non-saline soil. However, soil salinity often co-varies with other factors, making it difficult to assign responses of microbial communities to direct effects of salinity. A trait-based approach allows us to connect the environmental factor salinity with the responses of microbial community composition and functioning. Salinity along a salinity gradient serves as a filter for the community trait distribution of salt tolerance, selecting for higher salt tolerance at more saline sites. This trait-environment relationship can be used to predict responses of microbial communities to environmental change. Our aims were to (i) use salinity along natural salinity gradients as an environmental filter, and (ii) link the resulting filtered trait-distributions of the communities (the trait being salt tolerance) to the community composition. Soil samples were obtained from two replicated salinity gradients along an Australian salt lake, spanning a wide range of soil salinities (0.1 dS m-1 to >50 dS m-1). In one of the two gradients salinity was correlated with pH. Community trait distributions for salt tolerance were assessed by establishing dose-dependences for extracted bacterial communities using growth rate assays. In addition, functional parameters were measured along the salt gradients. Community composition of sites was compared through 16S rRNA gene amplicon sequencing. Microbial community composition changed greatly along the salinity gradients. Using the salt-tolerance assessments to estimate bacterial trait-distributions we could determine substantial differences in tolerance to salt revealing a strong causal connection between environment and trait distributions. By constraining the community composition with salinity tolerance in ordinations, we could assign which community differences were directly due to a shift in community trait distributions. These analyses revealed that a substantial part (up to 30%) of the community composition differences were directly driven by environmental salt concentrations.. Even though communities in saline soils had trait-distributions aligned to their environment, their performance (respiration, growth rates) was lower than those in non-saline soils and remained low even after input of organic material. Using a trait-based approach we could connect filtered trait distributions along environmental gradients, to the composition of the microbial community. We show that soil salinity played an important role in shaping microbial community composition by selecting for communities with higher salt tolerance. The shift toward bacterial communities with trait distributions matched to salt environments probably compensated for much of the potential loss of function induced by salinity, resulting in a degree of apparent functional redundancy for decomposition. However, more tolerant communities still showed reduced functioning, suggesting a trade-off between salt tolerance and performance.
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Fontanella, G H; Pascutti, M F; Daurelio, L; Perez, A R; Nocito, A L; Wojdyla, D; Bottasso, O; Revelli, S S; Stanford, J L
2007-04-30
The well-established model of Chagas' disease in "l" rats was used to evaluate the effects of three injections of heat-killed Gordonia bronchialis, Rhodococcus coprophilus or saline on Trypanosoma cruzi parasitaemia and acute and chronic myocarditis, sequelae of the infection. Two vaccinating injections were given prior to challenge with T. cruzi, and the third, immunotherapeutic, injection was given 7 days after challenge. Treatment with either actinomycete significantly reduced acute parasitaemia (p<0.04), modified cellular infiltration during acute myocarditis and limited chronic myocarditis (p<0.03) in comparison with the saline-treated control animals. Immunological investigations showed that both bacterial preparations achieved their results through different mechanisms. The relevance of our findings to human Chagas' disease is discussed.
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Whitehead, Andrew; Roach, Jennifer L; Zhang, Shujun; Galvez, Fernando
2012-04-15
The killifish Fundulus heteroclitus is abundant in osmotically dynamic estuaries and it can quickly adjust to extremes in environmental salinity. We performed a comparative osmotic challenge experiment to track the transcriptomic and physiological responses to two salinities throughout a time course of acclimation, and to explore the genome regulatory mechanisms that enable extreme osmotic acclimation. One southern and one northern coastal population, known to differ in their tolerance to hypo-osmotic exposure, were used as our comparative model. Both populations could maintain osmotic homeostasis when transferred from 32 to 0.4 p.p.t., but diverged in their compensatory abilities when challenged down to 0.1 p.p.t., in parallel with divergent transformation of gill morphology. Genes involved in cell volume regulation, nucleosome maintenance, ion transport, energetics, mitochondrion function, transcriptional regulation and apoptosis showed population- and salinity-dependent patterns of expression during acclimation. Network analysis confirmed the role of cytokine and kinase signaling pathways in coordinating the genome regulatory response to osmotic challenge, and also posited the importance of signaling coordinated through the transcription factor HNF-4α. These genome responses support hypotheses of which regulatory mechanisms are particularly relevant for enabling extreme physiological flexibility.
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Bianchini, Adalto; Lauer, Mariana Machado; Nery, Luiz Eduardo Maia; Colares, Elton Pinto; Monserrat, José María; Dos Santos Filho, Euclydes Antônio
2008-11-01
Neohelice granulata (Chasmagnathus granulatus) is an intertidal crab species living in salt marshes from estuaries and lagoons along the Atlantic coast of South America. It is a key species in these environments because it is responsible for energy transfer from producers to consumers. In order to deal with the extremely marked environmental salinity changes occurring in salt marshes, N. granulata shows important and interesting structural, biochemical, and physiological adaptations at the gills level. These adaptations characterize this crab as a euryhaline species, tolerating environmental salinities ranging from very diluted media to concentrated seawater. These characteristics had led to its use as an animal model to study estuarine adaptations in crustaceans. Therefore, the present review focuses on the influence of environmental salinity on N. granulata responses at the ecological, organismic and molecular levels. Aspects covered include salinity tolerance, osmo- and ionoregulatory patterns, morphological and structural adaptations at the gills, and mechanisms of ion transport and their regulation at the gills level during environmental salinity acclimation. Finally, this review compiles information on the effects of some environmental pollutants on iono- and osmoregulatory adaptations showed by N. granulata.
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Imbalanced nutrient regimes increase Prymnesium parvum resilience to herbicide exposure.
Flood, Stacie L; Burkholder, JoAnn M
2018-05-01
The toxigenic haptophyte Prymnesium parvum is a mixotrophic phytoplankter with an extensive historic record of forming nearly monospecific, high-biomass, ecosystem-disrupting blooms, and it has been responsible for major fish kills in brackish waters and aquaculture facilities in many regions of the world. Little is known about how this species responds to commonly occurring environmental contaminants, or how nutrient (nitrogen, phosphorus) pollution may interact with environmentally relevant pesticide exposures to affect this harmful algal species. Here, standard algal toxicity bioassays from pesticide hazard assessments were used along with modified erythrocyte lysis assays to evaluate how atrazine exposures, imbalanced nutrient supplies, and salinity interact to influence the growth and toxicity in P. parvum isolates from three different regions. In nutrient-replete media, P. parvum 96 h IC 50 s ranged from 73.0 to 88.3 μg atrazine L -1 at salinity 10 and from 118 to >200 μg atrazine μg L -1 at salinity 20, and the response depended on the strain and the test duration. Relative hemolytic activity, used as an indication of toxicity, was a function of herbicide exposure, nutrient availability, salinity, geographic origin, and interactions among these factors. Highest levels of hemolytic activity were measured from a South Carolina strain in low-nitrogen media with high atrazine concentrations. Herbicide concentration was related to relative hemolytic activity, although a consistent relationship between growth phase and toxicity was not observed. Overall, these findings suggest that increasing chemical contamination is helping to promote ecosystem-disruptive, strongly mixotrophic algal blooms. Copyright © 2018 Elsevier B.V. All rights reserved.
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A novel XRF method to measure environmental release of copper and zinc from antifouling paints.
Ytreberg, Erik; Lagerström, Maria; Holmqvist, Albin; Eklund, Britta; Elwing, Hans; Dahlström, Magnus; Dahl, Peter; Dahlström, Mia
2017-06-01
The release of copper (Cu) and zinc (Zn) from vessels and leisure crafts coated with antifouling paints can pose a threat to water quality in semi-enclosed areas such as harbors and marinas as well as to coastal archipelagos. However, no reliable, practical and low-cost method exists to measure the direct release of metals from antifouling paints. Therefore, the paint industry and regulatory authorities are obliged to use release rate measurements derived from either mathematical models or from laboratory studies. To bridge this gap, we have developed a novel method using a handheld X-Ray Fluorescence spectrometer (XRF) to determine the cumulative release of Cu and Zn from antifouling paints. The results showed a strong linear relationship between XRF K α net intensities and metal concentrations, as determined by ICP-MS. The release of Cu and Zn were determined for coated panels exposed in harbors located in the Baltic Sea and in Kattegat. The field study showed salinity to have a strong impact on the release of Cu, i.e. the release increased with salinity. Contrary, the effect of salinity on Zn was not as evident. As exemplified in this work, the XRF method also makes it possible to identify the governing parameters to the release of Cu and Zn, e.g. salinity and type of paint formulation. Thus, the XRF method can be used to measure environmentally relevant releases of metallic compounds to design more efficient and optimized antifouling coatings. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Smalley, A.M.; Saleh, F.M.S.; Fontenot, M.
1984-08-01
Baseline data relevant to air quality are presented. The following are also included: geology and resource assessment, design well prospects in southwestern Louisiana, water quality monitoring, chemical analysis subsidence, microseismicity, geopressure-geothermal subsidence modeling, models of compaction and subsidence, sampling handling and preparation, brine chemistry, wetland resources, socioeconomic characteristics, impacts on wetlands, salinity, toxic metals, non-metal toxicants, temperature, subsidence, and socioeconomic impacts. (MHR)
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Dickinson, Gary H; Ivanina, Anna V; Matoo, Omera B; Pörtner, Hans O; Lannig, Gisela; Bock, Christian; Beniash, Elia; Sokolova, Inna M
2012-01-01
Rising levels of atmospheric CO(2) lead to acidification of the ocean and alter seawater carbonate chemistry, which can negatively impact calcifying organisms, including mollusks. In estuaries, exposure to elevated CO(2) levels often co-occurs with other stressors, such as reduced salinity, which enhances the acidification trend, affects ion and acid-base regulation of estuarine calcifiers and modifies their response to ocean acidification. We studied the interactive effects of salinity and partial pressure of CO(2) (P(CO2)) on biomineralization and energy homeostasis in juveniles of the eastern oyster, Crassostrea virginica, a common estuarine bivalve. Juveniles were exposed for 11 weeks to one of two environmentally relevant salinities (30 or 15 PSU) either at current atmospheric P(CO2) (∼400 μatm, normocapnia) or P(CO2) projected by moderate IPCC scenarios for the year 2100 (∼700-800 μatm, hypercapnia). Exposure of the juvenile oysters to elevated P(CO2) and/or low salinity led to a significant increase in mortality, reduction of tissue energy stores (glycogen and lipid) and negative soft tissue growth, indicating energy deficiency. Interestingly, tissue ATP levels were not affected by exposure to changing salinity and P(CO2), suggesting that juvenile oysters maintain their cellular energy status at the expense of lipid and glycogen stores. At the same time, no compensatory upregulation of carbonic anhydrase activity was found under the conditions of low salinity and high P(CO2). Metabolic profiling using magnetic resonance spectroscopy revealed altered metabolite status following low salinity exposure; specifically, acetate levels were lower in hypercapnic than in normocapnic individuals at low salinity. Combined exposure to hypercapnia and low salinity negatively affected mechanical properties of shells of the juveniles, resulting in reduced hardness and fracture resistance. Thus, our data suggest that the combined effects of elevated P(CO2) and fluctuating salinity may jeopardize the survival of eastern oysters because of weakening of their shells and increased energy consumption.
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von Dewitz, Burkhard; Tamm, Susanne; Höflich, Katharina; Voss, Rüdiger; Hinrichsen, Hans-Harald
2018-01-01
The semi-enclosed nature and estuarine characteristics, together with its strongly alternating bathymetry, make the Baltic Sea prone to much stronger interannual variations in the abiotic environment, than other spawning habitats of Atlantic cod (Gadus morhua). Processes determining salinity and oxygen conditions in the basins are influenced both by long term gradual climate change, e.g. global warming, but also by short-term meteorological variations and events. Specifically one main factor influencing cod spawning conditions, the advection of highly saline and well-oxygenated water masses from the North Sea, is observed in irregular frequencies and causes strong interannual variations in stock productivity. This study investigates the possibility to use the available hydrographic process knowledge to predict the annual spawning conditions for Eastern Baltic cod in its most important spawning ground, the Bornholm Basin, only by salinity measurements from a specific location in the western Baltic. Such a prediction could serve as an environmental early warning indicator to inform stock assessment and management. Here we used a hydrodynamic model to hindcast hydrographic property fields for the last 40+ years. High and significant correlations were found for months early in the year between the 33m salinity level in the Arkona Basin and the oxygen-dependent cod spawning environment in the Bornholm Basin. Direct prediction of the Eastern Baltic cod egg survival in the Bornholm Basin based on salinity values in the Arkona Basin at the 33 m depth level is shown to be possible for eggs spawned by mid-age and young females, which currently predominate the stock structure. We recommend to routinely perform short-term predictions of the Eastern Baltic cod spawning environment, in order to generate environmental information highly relevant for stock dynamics. Our statistical approach offers the opportunity to make best use of permanently existing infrastructure in the western Baltic to timely provide scientific knowledge on the spawning conditions of Eastern Baltic cod. Furthermore it could be a tool to assist ecosystem-based fisheries management with a cost-effective implementation by including the short term predictions as a simple indicator in the annual assessments.
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Tamm, Susanne; Höflich, Katharina; Voss, Rüdiger; Hinrichsen, Hans-Harald
2018-01-01
The semi-enclosed nature and estuarine characteristics, together with its strongly alternating bathymetry, make the Baltic Sea prone to much stronger interannual variations in the abiotic environment, than other spawning habitats of Atlantic cod (Gadus morhua). Processes determining salinity and oxygen conditions in the basins are influenced both by long term gradual climate change, e.g. global warming, but also by short-term meteorological variations and events. Specifically one main factor influencing cod spawning conditions, the advection of highly saline and well-oxygenated water masses from the North Sea, is observed in irregular frequencies and causes strong interannual variations in stock productivity. This study investigates the possibility to use the available hydrographic process knowledge to predict the annual spawning conditions for Eastern Baltic cod in its most important spawning ground, the Bornholm Basin, only by salinity measurements from a specific location in the western Baltic. Such a prediction could serve as an environmental early warning indicator to inform stock assessment and management. Here we used a hydrodynamic model to hindcast hydrographic property fields for the last 40+ years. High and significant correlations were found for months early in the year between the 33m salinity level in the Arkona Basin and the oxygen-dependent cod spawning environment in the Bornholm Basin. Direct prediction of the Eastern Baltic cod egg survival in the Bornholm Basin based on salinity values in the Arkona Basin at the 33 m depth level is shown to be possible for eggs spawned by mid-age and young females, which currently predominate the stock structure. We recommend to routinely perform short-term predictions of the Eastern Baltic cod spawning environment, in order to generate environmental information highly relevant for stock dynamics. Our statistical approach offers the opportunity to make best use of permanently existing infrastructure in the western Baltic to timely provide scientific knowledge on the spawning conditions of Eastern Baltic cod. Furthermore it could be a tool to assist ecosystem-based fisheries management with a cost-effective implementation by including the short term predictions as a simple indicator in the annual assessments. PMID:29768443
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Annual growth patterns of baldcypress (Taxodium distichum) along salinity gradients
Thomas, Brenda L.; Doyle, Thomas W.; Krauss, Ken W.
2015-01-01
The effects of salinity on Taxodium distichum seedlings have been well documented, but few studies have examined mature trees in situ. We investigated the environmental drivers of T. distichum growth along a salinity gradient on the Waccamaw (South Carolina) and Savannah (Georgia) Rivers. On each river, T. distichum increment cores were collected from a healthy upstream site (Upper), a moderately degraded mid-reach site (Middle), and a highly degraded downstream site (Lower). Chronologies were successfully developed for Waccamaw Upper and Middle, and Savannah Middle. Correlations between standardized chronologies and environmental variables showed significant relationships between T. distichum growth and early growing season precipitation, temperature, and Palmer Drought Severity Index (PDSI). Savannah Middle chronology correlated most strongly with August river salinity levels. Both lower sites experienced suppression/release events likely in response to local anthropogenic impacts rather than regional environmental variables. The factors that affect T. distichum growth, including salinity, are strongly synergistic. As sea-level rise pushes the freshwater/saltwater interface inland, salinity becomes more limiting to T. distichum growth in tidal freshwater swamps; however, salinity impacts are exacerbated by locally imposed environmental modifications.
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Environmental Evaluation of Soil Salinity with Various Watering Technologies Assessment.
Seitkaziev, Adeubay; Shilibek, Kenzhegali; Fakhrudenova, Idiya; Salybayev, Satybaldy; Zhaparova, Sayagul; Duisenbayeva, Saule; Bayazitova, Zulfia; Aliya, Maimakova; Seitkazieva, Karlygash; Aubakirov, Hamit
2018-01-01
The purpose of this study is to develop mathematical tools for evaluating the level of environmental safety of various watering technologies. A set of indicators, was developed with regard to the natural factors, the nature of the man-induced load, degradation type, and characteristics of the disruption of humification conditions. Thermal and physical characteristics of the soil, the state of its surface, and meteorological factors, including air temperature, relative humidity, precipitation, wind speed, solar radiation, etc. were studied with a view to determining the heat and air exchange in the soil. An environmental evaluation of the methods for saline land development was conducted with regard to the heat and moisture supply. This tool can be used to determine the level of environmental safety of soil salinization during the environmental evaluation of the investigation of soil salinity with various watering technologies.
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NASA Astrophysics Data System (ADS)
Gnanachandrasamy, G.; Ramkumar, T.; Venkatramanan, S.; Chung, S. Y.; Vasudevan, S.
2016-06-01
We use electrical resistivity data arrayed in a 2715 km2 region with 30 locations to identify the saline water intrusion zone in part of Cauvery deltaic region, offshore Eastern India. From this dataset we are able to derive information on groundwater quality, thickness of aquifer zone, structural and stratigraphic conditions relevant to groundwater conditions, and permeability of aquifer systems. A total of 30 vertical electrode soundings (VES) were carried out by Schlumberger electrode arrangement to indicate complete lithology of this region using curve matching techniques. The electrical soundings exhibited that H and HK type curves were suitable for 16 shallow locations, and QH, KQ, K, KH, QQ, and HA curves were fit for other location. Low resistivity values suggested that saline water intrusion occurred in this region. According to final GIS map, most of the region was severely affected by seawater intrusion due to the use of over-exploitation of groundwater.The deteriorated groundwater resources in this coastal region should raise environmental and health concerns.
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Bayer-Giraldi, Maddalena; Weikusat, Ilka; Besir, Hüseyin; Dieckmann, Gerhard
2011-12-01
Antifreeze proteins (AFPs), characterized by their ability to separate the melting and growth temperatures of ice and to inhibit ice recrystallization, play an important role in cold adaptation of several polar and cold-tolerant organisms. Recently, a multigene family of AFP genes was found in the diatom Fragilariopsis cylindrus, a dominant species within polar sea ice assemblages. This study presents the AFP from F. cylindrus set in a molecular and crystallographic frame. Differential protein expression after exposure of the diatoms to environmentally relevant conditions underlined the importance of certain AFP isoforms in response to cold. Analyses of the recombinant AFP showed freezing point depression comparable to the activity of other moderate AFPs and further enhanced by salt (up to 0.9°C in low salinity buffer, 2.5°C at high salinity). However, unlike other moderate AFPs, its fastest growth direction is perpendicular to the c-axis. The protein also caused strong inhibition of recrystallization at concentrations of 1.2 and 0.12 μM at low and high salinity, respectively. Observations of crystal habit modifications and pitting activity suggested binding of AFPs to multiple faces of the ice crystals. Further analyses showed striations caused by AFPs, interpreted as inclusion in the ice. We suggest that the influence on ice microstructure is the main characteristic of these AFPs in sea ice. Copyright © 2011 Elsevier Inc. All rights reserved.
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Disentangling diversity patterns in sandy beaches along environmental gradients.
Barboza, Francisco R; Gómez, Julio; Lercari, Diego; Defeo, Omar
2012-01-01
Species richness in sandy beaches is strongly affected by concurrent variations in morphodynamics and salinity. However, as in other ecosystems, different groups of species may exhibit contrasting patterns in response to these environmental variables, which would be obscured if only aggregate richness is considered. Deconstructing biodiversity, i.e. considering richness patterns separately for different groups of species according to their taxonomic affiliation, dispersal mode or mobility, could provide a more complete understanding about factors that drive species richness patterns. This study analyzed macroscale variations in species richness at 16 Uruguayan sandy beaches with different morphodynamics, distributed along the estuarine gradient generated by the Rio de la Plata over a 2 year period. Species richness estimates were deconstructed to discriminate among taxonomic groups, supralittoral and intertidal forms, and groups with different feeding habits and development modes. Species richness was lowest at intermediate salinities, increasing towards oceanic and inner estuarine conditions, mainly following the patterns shown for intertidal forms. Moreover, there was a differential tolerance to salinity changes according to the habitat occupied and development mode, which determines the degree of sensitivity of faunal groups to osmotic stress. Generalized (additive and linear) mixed models showed a clear increase of species richness towards dissipative beaches. All taxonomic categories exhibited the same trend, even though responses to grain size and beach slope were less marked for crustaceans and insects than for molluscs or polychaetes. However, supralittoral crustaceans exhibited the opposite trend. Feeding groups decreased from dissipative to reflective systems, deposit feeders being virtually absent in the latter. This deconstructive approach highlights the relevance of life history strategies in structuring communities, highlighting the relative importance that salinity and morphodynamic gradients have on macroscale diversity patterns in sandy beaches.
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NASA Astrophysics Data System (ADS)
Fanini, L.; Zampicinini, G.; Tsigenopoulos, C. S.; Barboza, F. R.; Lozoya, J. P.; Gómez, J.; Celentano, E.; Lercari, D.; Marchetti, G. M.; Defeo, O.
2017-03-01
Life-history, substrate choice and Cytochrome Oxidase I (COI) sequences were analysed in populations of two peracaridans, the supralittoral talitrid Atlantorchestoidea brasiliensis and the intertidal cirolanid Excirolana armata. Three populations of each species, from beaches with similar grain size and located at different points along the natural gradient generated by the Rio de la Plata estuary were analysed. Abundance of E. armata increased with distance from the estuary, while the opposite trend was observed for A. brasiliensis. The proportion of females decreased towards high salinities for both species, significantly for E. armata. A test on substrate salinity preference revealed the absence of patterns due to active choice in E. armata. By contrast, A. brasiliensis showed no preference for the population closer to the estuary, while individuals from the other two sites significantly preferred high salinity substrates. Mitochondrial COI sequences were obtained from A. brasiliensis specimens tested for behaviour. Sequence analysis showed the population from the intermediate site to differ significantly from the other two. No significant genetic differentiation was instead found between populations from the two most distant sites, nor between individuals that expressed different salinity preference. Results showed that diverse sets of traits at the population level enable sandy beach species to cope with local environmental changes: life-history and behavioural traits appear to change in response to different ecological conditions, and, in the case of A brasiliensis, independently of the population structure inferred from COI sequence variation. Information from multiple traits allowed detection of population profiles, highlighting the relevance of multidisciplinary information and the concurrent analysis of field data and laboratory experiments, to detect responses of resident biota to environmental changes.
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1989-03-01
size only by Music 1979). molting (Hay 1905). Zoeal development depends on salinity and temperature, Growth and maturation proceed but development time...substrates. the effects depends on the toxicant, concentration, time exposed, salinity , tidal cycle, age and molt phase of Other Environmental Factors...Temperature .......................................................... 11 Salinity ............................................................. I11
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Day-Lewis, F. D.; White, E.A.; Johnson, C.D.; Lane, J.W.; Belaval, M.
2006-01-01
Aquifer-ocean interaction, saline intrusion, and submarine groundwater discharge (SGD) are emerging topics in hydrology and oceanography with important implications for water-resource management and estuarine ecology. Although the threat of saltwater intrusion has long been recognized in coastal areas, SGD has, until recently, received much less attention. It is clear that SGD constitutes a major nutrient flux to coastal waters, with implications for estuarine ecology, eutrophication, and loss of coral reefs; however, fundamental questions regarding SGD remain unanswered: What are the spatial and temporal distributions of SGD offshore? How do seasonal and storm-related variations in aquifer recharge affect SGD flux and nutrient loading? What controls do aquifer structure and heterogeneity impose? How are SGD and saline recirculation related? Geophysical methods can provide insights to help answer these questions and improve the understanding of this intriguing and environmentally relevant hydrologic phenomenon. ?? 2006 Society of Exploration Geophysicists.
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1985-04-01
osmoconformer at salinities greater ENVIRONMENTAL REQUIREMENTS than 10 ppt, and an osmoregulator at lower salinities (Bedford and Anderson 1972a,b; Otto...1973, 1974) tested the combined effects of temperature (8 to 32°C) and salinity (0 to 20 ppt) on .. k6.. Temperature embryos and larvae of common...Bedford, W. B. , and J. W. Anderson. Allen, K. 1961. The effect of salin - 1972a. The physiological response ity on the amino acid concentra- of the
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Wurlod, Virginie A; Howard, Judith; Francey, Thierry; Schweighauser, Ariane; Adamik, Katja N
2015-01-01
To compare the in vitro effects of hypertonic solutions and colloids to saline on coagulation in dogs. In vitro experimental study. Veterinary teaching hospital. Twenty-one adult dogs. Blood samples were diluted with saline, 7.2% hypertonic saline solution with 6% hydroxyethylstarch with an average molecular weight of 200 kDa and a molar substitution of 0.4 (HH), 7.2% hypertonic saline (HTS), hydroxyethyl starch (HES) 130/0.4 or hydroxyethyl starch 600/0.75 at ratios of 1:22 and 1:9, and with saline and HES at a ratio of 1:3. Whole blood coagulation was analyzed using rotational thromboelastometry (extrinsic thromboelastometry-cloting time (ExTEM-CT), maximal clot firmness (MCF) and clot formation time (CFT) and fibrinogen function TEM-CT (FibTEM-CT) and MCF) and platelet function was analyzed using a platelet function analyzer (closure time, CTPFA ). All parameters measured were impaired by saline dilution. The CTPFA was prolonged by 7.2% hypertonic saline solution with 6% hydroxyethylstarch with an average molecular weight of 200 kDa and a molar substitution of 0.4 (HH) and HTS but not by HES solutions. At clinical dilutions equivalent to those generally administered for shock (saline 1:3, HES 1:9, and hypertonic solutions 1:22), CTPFA was more prolonged by HH and HTS than other solutions but more by saline than HES. No difference was found between the HES solutions or the hypertonic solutions. ExTEM-CFT and MCF were impaired by HH and HTS but only mildly by HES solutions. At clinically relevant dilutions, no difference was found in ExTEM-CFT between HTS and saline or in ExTEM-MCF between HH and saline. No consistent difference was found between the 2 HES solutions but HH impaired ExTEM-CFT and MCF more than HTS. At high dilutions, FibTEM-CT and -MCF and ExTEM-CT were impaired by HES. Hypertonic solutions affect platelet function and whole blood coagulation to a greater extent than saline and HES. At clinically relevant dilutions, only CTPFA was markedly more affected by hypertonic solutions than by saline. At high dilutions, HES significantly affects coagulation but to no greater extent than saline at clinically relevant dilutions. © Veterinary Emergency and Critical Care Society 2015.
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García-Roger, Eduardo Moisés; Franch, Belen; Carmona, María José; Serra, Manuel
2017-01-01
Fluctuations in environmental parameters are increasingly being recognized as essential features of any habitat. The quantification of whether environmental fluctuations are prevalently predictable or unpredictable is remarkably relevant to understanding the evolutionary responses of organisms. However, when characterizing the relevant features of natural habitats, ecologists typically face two problems: (1) gathering long-term data and (2) handling the hard-won data. This paper takes advantage of the free access to long-term recordings of remote sensing data (27 years, Landsat TM/ETM+) to assess a set of environmental models for estimating environmental predictability. The case study included 20 Mediterranean saline ponds and lakes, and the focal variable was the water-surface area. This study first aimed to produce a method for accurately estimating the water-surface area from satellite images. Saline ponds can develop salt-crusted areas that make it difficult to distinguish between soil and water. This challenge was addressed using a novel pipeline that combines band ratio water indices and the short near-infrared band as a salt filter. The study then extracted the predictable and unpredictable components of variation in the water-surface area. Two different approaches, each showing variations in the parameters, were used to obtain the stochastic variation around a regular pattern with the objective of dissecting the effect of assumptions on predictability estimations. The first approach, which is based on Colwell’s predictability metrics, transforms the focal variable into a nominal one. The resulting discrete categories define the relevant variations in the water-surface area. In the second approach, we introduced General Additive Model (GAM) fitting as a new metric for quantifying predictability. Both approaches produced a wide range of predictability for the studied ponds. Some model assumptions–which are considered very different a priori–had minor effects, whereas others produced predictability estimations that showed some degree of divergence. We hypothesize that these diverging estimations of predictability reflect the effect of fluctuations on different types of organisms. The fluctuation analysis described in this manuscript is applicable to a wide variety of systems, including both aquatic and non-aquatic systems, and will be valuable for quantifying and characterizing predictability, which is essential within the expected global increase in the unpredictability of environmental fluctuations. We advocate that a priori information for organisms of interest should be used to select the most suitable metrics for estimating predictability, and we provide some guidelines for this approach. PMID:29121667
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Yang, Jian; Ma, Li'an; Jiang, Hongchen; Wu, Geng; Dong, Hailiang
2016-04-26
Investigating microbial response to environmental variables is of great importance for understanding of microbial acclimatization and evolution in natural environments. However, little is known about how microbial communities responded to environmental factors (e.g. salinity, geographic distance) in lake surface sediments of the Qinghai-Tibetan Plateau (QTP). In this study, microbial diversity and community structure in the surface sediments of nine lakes on the QTP were investigated by using the Illumina Miseq sequencing technique and the resulting microbial data were statistically analyzed in combination with environmental variables. The results showed total microbial community of the studied lakes was significantly correlated (r = 0.631, P < 0.001) with lake salinity instead of geographic distance. This suggests that lake salinity is more important than geographic distance in shaping the microbial diversity and community structure in the studied samples. In addition, the abundant and rare taxa (OTUs with relative abundance higher than 1% and lower than 0.01% within one sample, respectively) were significantly (P < 0.05) correlated (r = 0.427 and 0.783, respectively) with salinity, suggesting rare taxa might be more sensitive to salinity than their abundant counterparts, thus cautions should be taken in future when evaluating microbial response (abundant vs. rare sub-communities) to environmental conditions.
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Curry, B. Brandon
1999-01-01
Continental ostracode occurrences reflect salinity, solute composition, temperature, flow conditions, and other environmental properties of the water they inhabit. Their occurrences also reflect the variability of many of these environmental parameters. Environmental tolerance indices (ETIs) offer a new way to express the nature of an ostracode's environment. As defined herein, ETIs range in value from zero to one, and may be calculated for continuous and binary variables. For continuous variables such as salinity, the ETI is the ratio of the range of values of salinity tolerated by an ostracode to the total range of salinity values from a representative database. In this investigation, the database of continuous variables consists of information from 341 sites located throughout the United States. Binary ETIs indicate whether an environmental variable such as flowing water affects ostracode presence or absence. The binary database consists of information from 784 sites primarily from Illinois, USA. ETIs were developed in this investigation to interpret paleohydrological changes implied by fossil ostracode successions. ETI profiles may be cast in terms of a weighted average, or on presence/absence. The profiles express ostracode tolerance of environmental parameters such as salinity or currents. Tolerance of a wide range of values is taken to indicate shallow water because shallow environments are conducive to thermal variability, short-term water residence, and the development of currents from wind-driven waves.
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Historical and contemporary environmental context for the Saline-Fifteen site (3BR119)
Don C. Bragg; Hope A. Bragg
2016-01-01
This paper summarizes the historical environmental context of the Saline-Fifteen site (3BR119) in Bradley County, Arkansas, developed from the General Land Office (GLO) public land surveys, other old documents, and an examination of current forest inventories and modern research to approximate past environmental attributes for this locality. While an imperfect source...
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NASA Astrophysics Data System (ADS)
Jänchen, Jochen; Feyh, Nina; Szewzyk, Ulrich; de Vera, Jean-Pierre P.
2016-04-01
Motivated by findings of new mineral related water sources for organisms under extremely dry conditions on Earth we studied in an interdisciplinary approach the water sorption behaviour of halite, soil component and terrestrial Nostoc commune biofilm under Mars relevant environmental conditions. Physicochemical methods served for the determination of water sorption equilibrium data and survival of heterotrophic bacteria in biofilm samples with different water contents was assured by recultivation. Deliquescence of halite provides liquid water at temperatures <273 K and may serve as water source on Mars during the morning stabilized by the CO2 atmosphere for a few hours. The protecting biofilm of N. commune is rather hygroscopic and tends to store water at lower humidity values. Survival tests showed that a large proportion of the Alphaproteobacteria dominated microbiota associated to N. commune is very desiccation tolerant and water uptake from saturated NaCl solutions (either by direct uptake of brine or adsorption of humidity) did not enhance recultivability in long-time desiccated samples. Still, a minor part can grow under highly saline conditions. However, the salinity level, although unfavourable for the host organism, might be for parts of the heterotrophic microbiota no serious hindrance for growing in salty Mars-like environments.
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Biotic variation in coastal water bodies in Sussex, England: Implications for saline lagoons
NASA Astrophysics Data System (ADS)
Joyce, Chris B.; Vina-Herbon, Cristina; Metcalfe, Daniel J.
2005-12-01
Coastal water bodies are a heterogeneous resource typified by high spatial and temporal variability and threatened by anthropogenic impacts. This includes saline lagoons, which support a specialist biota and are a priority habitat for nature conservation. This paper describes the biotic variation in coastal water bodies in Sussex, England, in order to characterise the distinctiveness of the saline lagoon community and elucidate environmental factors that determine its distribution. Twenty-eight coastal water bodies were surveyed for their aquatic flora and invertebrate fauna and a suite of exploratory environmental variables compiled. Ordination and cluster analyses were used to examine patterns in community composition and relate these to environmental parameters. Biotic variation in the coastal water body resource was high. Salinity was the main environmental parameter explaining the regional distribution of taxa; freshwater and saline assemblages were evident and related to sea water ingress. Freshwater sites were indicated by the plant Myriophyllum spicatum and gastropod mollusc Lymnaea peregra, while more saline communities supported marine and brackish water taxa, notably a range of chlorophytic algae and the bivalve mollusc Cerastoderma glaucum. Site community differences were also related to bank slope and parameters describing habitat heterogeneity. A saline lagoon community was discerned within the matrix of biotic variation consisting of specialist lagoonal species with associated typically euryhaline taxa. For fauna, the latter were the molluscs Abra tenuis and Hydrobia ulvae, and the crustaceans Corophium volutator and Palaemonetes varians, and for flora they were the algae Ulva lactuca, Chaetomorpha mediterranea, Cladophora spp. and Enteromorpha intestinalis. One non-native polychaete species, Ficopomatus enigmaticus, also strongly influenced community structure within the lagoonal resource. The community was not well defined as specialist and associated taxa were distributed throughout the spectrum of sites surveyed. Implications for the identification and conservation of saline lagoons are discussed.
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Environmental sustainability of bioethanol produced from sweet sorghum stem on saline-alkali land.
Wang, Mingxin; Pan, Xinxing; Xia, Xunfeng; Xi, Beidou; Wang, Lijun
2015-01-01
Life cycle assessment was conducted to evaluate the energy efficiency and environmental impacts of a bioethanol production system that uses sweet sorghum stem on saline-alkali land as feedstock. The system comprises a plant cultivation unit, a feedstock transport unit, and a bioethanol conversion unit, with 1000L of bioethanol as a functional unit. The net energy ratio is 3.84, and the net energy gain is 17.21MJ/L. Agrochemical production consumes 76.58% of the life cycle fossil energy. The category with the most significant impact on the environment is eutrophication, followed by acidification, fresh water aquatic ecotoxicity, human toxicity, and global warming. Allocation method, waste recycling approach, and soil salinity significantly influence the results. Using vinasse to produce pellet fuel for steam generation significantly improves energy efficiency and decreases negative environmental impacts. Promoting reasonable management practices to alleviate saline stress and increasing agrochemical utilization efficiency can further improve environmental sustainability. Copyright © 2015 Elsevier Ltd. All rights reserved.
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[Spatial differentiation and impact factors of Yutian Oasis's soil surface salt based on GWR model].
Yuan, Yu Yun; Wahap, Halik; Guan, Jing Yun; Lu, Long Hui; Zhang, Qin Qin
2016-10-01
In this paper, topsoil salinity data gathered from 24 sampling sites in the Yutian Oasis were used, nine different kinds of environmental variables closely related to soil salinity were selec-ted as influencing factors, then, the spatial distribution characteristics of topsoil salinity and spatial heterogeneity of influencing factors were analyzed by combining the spatial autocorrelation with traditional regression analysis and geographically weighted regression model. Results showed that the topsoil salinity in Yutian Oasis was not of random distribution but had strong spatial dependence, and the spatial autocorrelation index for topsoil salinity was 0.479. Groundwater salinity, groundwater depth, elevation and temperature were the main factors influencing topsoil salt accumulation in arid land oases and they were spatially heterogeneous. The nine selected environmental variables except soil pH had significant influences on topsoil salinity with spatial disparity. GWR model was superior to the OLS model on interpretation and estimation of spatial non-stationary data, also had a remarkable advantage in visualization of modeling parameters.
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Jeong, Yoonah; Schäffer, Andreas; Smith, Kilian
2017-05-01
Oasis hydrophilic lipophilic balance ® (Oasis HLB) is commonly employed in solid phase extraction (SPE) of environmental contaminants and within polar organic chemical integrative passive samplers (POCIS). In this study batch experiments were carried out to evaluate the relative affinity of a range of relevant organic pollutants to Oasis HLB in aqueous systems. The influence of sorbate concentration, temperature, pH, and salinity on the equilibrium sorption was investigated. Equilibrium partition ratios (K D ) of 28 compounds were determined, ranging over three orders of magnitude from 1.16 × 10 3 L/kg (atenolol) to 1.07 × 10 6 L/kg (isoproturon). The Freundlich model was able to describe the equilibrium partitioning to Oasis HLB, and an analysis of the thermodynamic parameters revealed the spontaneous and exothermic nature of the partitioning process. Ionic strength had only a minor effect on the partitioning, whereas pH had a considerable effect but only for ionizable compounds. The results show that apolar interactions between the Oasis HLB and analyte mainly determine the equilibrium partitioning. These research findings can be used to optimize the application of SPE and POCIS for analyses of environmental contaminants even in complex mixtures. Copyright © 2017 Elsevier Ltd. All rights reserved.
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NASA Astrophysics Data System (ADS)
Lowe, A. T.; Roberts, E. A.; Galloway, A. W. E.
2016-02-01
Coastal regions around the world are changing rapidly, generating many physiological stressors for marine organisms. Food availability, a major factor determining physiological condition of marine organisms, in these systems reflects the influence of biological and environmental factors, and will likely respond dramatically to long-term changes. Using observations of phytoplankton, detritus, and their corresponding fatty acids and stable isotopes of carbon, nitrogen and sulfur, we identified environmental drivers of pelagic food availability and quality along a salinity gradient in a large tidally influenced estuary (San Juan Archipelago, Salish Sea, USA). Variation in chlorophyll a (Chl a), biomarkers and environmental conditions exhibited a similar range at both tidal and seasonal scales, highlighting a tide-related mechanism controlling productivity that is important to consider for long-term monitoring. Multiple parameters of food availability were inversely and non-linearly correlated to salinity, such that availability of high-quality (based on abundance, essential fatty acid concentration and C:N) seston increased below a salinity threshold of 30. The increased marine productivity was associated with increased pH and dissolved oxygen (DO) at lower salinity. Based on this observation we predicted that a decrease of salinity to below the threshold would result in higher Chl a, temperature, DO and pH across a range of temporal and spatial scales, and tested the prediction with a meta-analysis of available data. At all scales, these variables showed significant and consistent increases related to the salinity threshold. This finding provides important context to the increased frequency of below-threshold salinity over the last 71 years in this region, suggesting greater food availability with positive feedbacks on DO and pH. Together, these findings indicate that many of the environmental factors predicted to increase physiological stress to benthic suspension feeders (e.g. decreased salinity) may simultaneously and paradoxically improve conditions for benthic organisms.
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1989-12-01
temperature affected survival at different shelter has been suggested as an important salinities and salinity affected survival at mechanism of nutrient...10 Salinity . . . . .. . . . . .. . . . .. . .. . .. . .. .. . .. .. .. .. . .. . . .. . .. . . . . .. . . . 11 Temperature- Salinity ...members of the tribe Caridca by four features Order .................... Decapoda (Figure 3); (1)-the rostrum is very short, Suborder
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Impact of Nutrition and Salinity Changes on Biological Performances of Green and White Sturgeon
Vaz, Pedro G.; Kebreab, Ermias; Hung, Silas S. O.; Fadel, James G.; Lee, Seunghyung; Fangue, Nann A.
2015-01-01
Green and white sturgeon are species of high conservational and economic interest, particularly in the San Francisco Bay Delta (SFBD) for which significant climate change-derived alterations in salinity and nutritional patterns are forecasted. Although there is paucity of information, it is critical to test the network of biological responses underlying the capacity of animals to tolerate current environmental changes. Through nutrition and salinity challenges, climate change will likely have more physiological effect on young sturgeon stages, which in turn may affect growth performance. In this study, the two species were challenged in a multiple-factor experimental setting, first to levels of feeding rate, and then to salinity levels for different time periods. Data analysis included generalized additive models to select predictors of growth performance (measured by condition factor) among the environmental stressors considered and a suite of physiological variables. Using structural equation modeling, a path diagram is proposed to quantify the main linkages among nutrition status, salinity, osmoregulation variables, and growth performances. Three major trends were anticipated for the growth performance of green and white sturgeon in the juvenile stage in the SFBD: (i) a decrease in prey abundance will be highly detrimental for the growth of both species; (ii) an acute increase in salinity within the limits studied can be tolerated by both species but possibly the energy spent in osmoregulation may affect green sturgeon growth within the time window assessed; (iii) the mechanism of synergistic effects of nutrition and salinity changes will be more complex in green sturgeon, with condition factor responding nonlinearly to interactions of salinity and nutrition status or time of salinity exposure. Green sturgeon merits special scientific attention and conservation effort to offset the effects of feed restriction and salinity as key environmental stressors in the SFBD. PMID:25830227
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Impact of nutrition and salinity changes on biological performances of green and white sturgeon.
Vaz, Pedro G; Kebreab, Ermias; Hung, Silas S O; Fadel, James G; Lee, Seunghyung; Fangue, Nann A
2015-01-01
Green and white sturgeon are species of high conservational and economic interest, particularly in the San Francisco Bay Delta (SFBD) for which significant climate change-derived alterations in salinity and nutritional patterns are forecasted. Although there is paucity of information, it is critical to test the network of biological responses underlying the capacity of animals to tolerate current environmental changes. Through nutrition and salinity challenges, climate change will likely have more physiological effect on young sturgeon stages, which in turn may affect growth performance. In this study, the two species were challenged in a multiple-factor experimental setting, first to levels of feeding rate, and then to salinity levels for different time periods. Data analysis included generalized additive models to select predictors of growth performance (measured by condition factor) among the environmental stressors considered and a suite of physiological variables. Using structural equation modeling, a path diagram is proposed to quantify the main linkages among nutrition status, salinity, osmoregulation variables, and growth performances. Three major trends were anticipated for the growth performance of green and white sturgeon in the juvenile stage in the SFBD: (i) a decrease in prey abundance will be highly detrimental for the growth of both species; (ii) an acute increase in salinity within the limits studied can be tolerated by both species but possibly the energy spent in osmoregulation may affect green sturgeon growth within the time window assessed; (iii) the mechanism of synergistic effects of nutrition and salinity changes will be more complex in green sturgeon, with condition factor responding nonlinearly to interactions of salinity and nutrition status or time of salinity exposure. Green sturgeon merits special scientific attention and conservation effort to offset the effects of feed restriction and salinity as key environmental stressors in the SFBD.
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1998-04-01
from estuarine waters F-12 12 up to 14 ppt salinity (Moyle et al. 1992). For a large part of its annual life span, this species is associated...with the freshwater edge of the mixing zone (saltwater-freshwater interface), where the salinity is approximately 2 ppt (Ganssle 1966, Moyle et al...1992, Sweetnam and Stevens 1993). The delta smelt is adapted to living in the highly productive Estuary where salinity varies spatially and
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Environmental tolerances of rare and common mangroves along light and salinity gradients.
Dangremond, Emily M; Feller, Ilka C; Sousa, Wayne P
2015-12-01
Although mangroves possess a variety of morphological and physiological adaptations for life in a stressful habitat, interspecific differences in survival and growth under different environmental conditions can shape their local and geographic distributions. Soil salinity and light are known to affect mangrove performance, often in an interactive fashion. It has also been hypothesized that mangroves are intrinsically shade intolerant due to the high physiological cost of coping with saline flooded soils. To evaluate the relationship between stress tolerance and species distributions, we compared responses of seedlings of three widespread mangrove species and one narrow endemic mangrove species in a factorial array of light levels and soil salinities in an outdoor laboratory experiment. The more narrowly distributed species was expected to exhibit a lower tolerance of potentially stressful conditions. Two of the widespread species, Avicennia germinans and Lumnitzera racemosa, survived and grew well at low-medium salinity, regardless of light level, but performed poorly at high salinity, particularly under high light. The third widespread species, Rhizophora mangle, responded less to variation in light and salinity. However, at high salinity, its relative growth rate was low at every light level and none of these plants flushed leaves. As predicted, the rare species, Pelliciera rhizophorae, was the most sensitive to environmental stressors, suffering especially high mortality and reduced growth and quantum yield under the combined conditions of high light and medium-high salinity. That it only thrives under shaded conditions represents an important exception to the prevailing belief that halophytes are intrinsically constrained to be shade intolerant.
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The assessment of spatial distribution of soil salinity risk using neural network.
Akramkhanov, Akmal; Vlek, Paul L G
2012-04-01
Soil salinity in the Aral Sea Basin is one of the major limiting factors of sustainable crop production. Leaching of the salts before planting season is usually a prerequisite for crop establishment and predetermined water amounts are applied uniformly to fields often without discerning salinity levels. The use of predetermined water amounts for leaching perhaps partly emanate from the inability of conventional soil salinity surveys (based on collection of soil samples, laboratory analyses) to generate timely and high-resolution salinity maps. This paper has an objective to estimate the spatial distribution of soil salinity based on readily or cheaply obtainable environmental parameters (terrain indices, remote sensing data, distance to drains, and long-term groundwater observation data) using a neural network model. The farm-scale (∼15 km(2)) results were used to upscale soil salinity to a district area (∼300 km(2)). The use of environmental attributes and soil salinity relationships to upscale the spatial distribution of soil salinity from farm to district scale resulted in the estimation of essentially similar average soil salinity values (estimated 0.94 vs. 1.04 dS m(-1)). Visual comparison of the maps suggests that the estimated map had soil salinity that was uniform in distribution. The upscaling proved to be satisfactory; depending on critical salinity threshold values, around 70-90% of locations were correctly estimated.
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1986-08-01
variety of factors crab eggs has been linked to increased including depth, latitude, tempera- egg mortality because of mechanical ture, salinity and...time. crabs seem less dependent on epibenthic cover and can be found over more exposed substrates. Most crabs Temperature- Salinity Interactions remain...13 Salinity . .. ....... ........................................ 14 Temperature- Salinity Interactions. .. .... ....... ....... 14
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Handley-Sidhu, Stephanie; Mullan, Thomas K.; Grail, Quentin; Albadarneh, Malek; Ohnuki, Toshihiko; Macaskie, Lynne E.
2016-01-01
Anthropogenic radionuclides contaminate a range of environments as a result of nuclear activities, for example, leakage from waste storage tanks/ponds (e.g. Hanford, USA or Sellafield sites, UK) or as a result of large scale nuclear accidents (e.g. Chernobyl, Ukraine or Fukushima, Japan). One of the most widely applied remediation techniques for contaminated waters is the use of sorbent materials (e.g. zeolites and apatites). However, a key problem at nuclear contaminated sites is the remediation of radionuclides from complex chemical environments. In this study, biogenic hydroxyapatite (BHAP) produced by Serratia sp. bacteria was investigated for its potential to remediate surrogate radionuclides (Sr2+ and Co2+) from environmentally relevant waters by varying pH, salinity and the type and concentration of cations present. The sorption capacity of the BHAP for both Sr2+ and Co2+ was higher than for a synthetically produced hydroxyapatite (HAP) in the solutions tested. BHAP also compared favorably against a natural zeolite (as used in industrial decontamination) for Sr2+ and Co2+ uptake from saline waters. Results confirm that hydroxyapatite minerals of high surface area and amorphous calcium phosphate content, typical for biogenic sources, are suitable restoration or reactive barrier materials for the remediation of complex contaminated environments or wastewaters. PMID:26988070
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NASA Astrophysics Data System (ADS)
Handley-Sidhu, Stephanie; Mullan, Thomas K.; Grail, Quentin; Albadarneh, Malek; Ohnuki, Toshihiko; Macaskie, Lynne E.
2016-03-01
Anthropogenic radionuclides contaminate a range of environments as a result of nuclear activities, for example, leakage from waste storage tanks/ponds (e.g. Hanford, USA or Sellafield sites, UK) or as a result of large scale nuclear accidents (e.g. Chernobyl, Ukraine or Fukushima, Japan). One of the most widely applied remediation techniques for contaminated waters is the use of sorbent materials (e.g. zeolites and apatites). However, a key problem at nuclear contaminated sites is the remediation of radionuclides from complex chemical environments. In this study, biogenic hydroxyapatite (BHAP) produced by Serratia sp. bacteria was investigated for its potential to remediate surrogate radionuclides (Sr2+ and Co2+) from environmentally relevant waters by varying pH, salinity and the type and concentration of cations present. The sorption capacity of the BHAP for both Sr2+ and Co2+ was higher than for a synthetically produced hydroxyapatite (HAP) in the solutions tested. BHAP also compared favorably against a natural zeolite (as used in industrial decontamination) for Sr2+ and Co2+ uptake from saline waters. Results confirm that hydroxyapatite minerals of high surface area and amorphous calcium phosphate content, typical for biogenic sources, are suitable restoration or reactive barrier materials for the remediation of complex contaminated environments or wastewaters.
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Characteristics of silver nanoparticles in vehicles for biological applications.
Kejlová, Kristina; Kašpárková, Věra; Krsek, Daniel; Jírová, Dagmar; Kolářová, Hana; Dvořáková, Markéta; Tománková, Kateřina; Mikulcová, Veronika
2015-12-30
Silver nanoparticles (AgNPs) have been used for decades as anti-bacterial agents in various industrial fields such as cosmetics, health industry, food storage, textile coatings and environmental applications, although their toxicity is not fully recognized yet. Antimicrobial and catalytic activity of AgNPs depends on their size as well as structure, shape, size distribution, and physico-chemical environment. The unique properties of AgNPs require novel or modified toxicological methods for evaluation of their toxic potential combined with robust analytical methods for characterization of nanoparticles applied in relevant vehicles, e.g., culture medium with/without serum and phosphate buffered saline. Copyright © 2015 Elsevier B.V. All rights reserved.
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Implications of salinity pollution hotspots on agricultural production
NASA Astrophysics Data System (ADS)
Floerke, Martina; Fink, Julia; Malsy, Marcus; Voelker, Jeanette; Alcamo, Joseph
2016-04-01
Salinity pollution can have many negative impacts on water resources used for drinking, irrigation, and industrial purposes. Elevated concentrations of salinity in irrigation water can lead to decreased crop production or crop death and, thus, causing an economic problem. Overall, salinity pollution is a global problem but tends to be more severe in arid and semi-arid regions where the dilution capacity of rivers and lakes is lower and the use of irrigation higher. Particularly in these regions agricultural production is exposed to high salinity of irrigation water as insufficient water quality further reduces the available freshwater resources. According to the FAO, irrigated agriculture contributes about 40 percent of the total food production globally, and therefore, high salinity pollution poses a major concern for food production and food security. We use the WaterGAP3 modeling framework to simulate hydrological, water use, and water quality conditions on a global scale for the time period 1990 to 2010. The modeling framework is applied to simulate total dissolved solids (TDS) loadings and in-stream concentrations from different point and diffuse sources to get an insight on potential environmental impacts as well as risks to agricultural food production. The model was tested and calibrated against observed data from GEMStat and literature sources. Although global in scope, the focus of this study is on developing countries, i.e., in Africa, Asia, and Latin America, as these are most threatened by salinity pollution. Furthermore, insufficient water quality for irrigation and therefore restrictions in irrigation water use are examined, indicating limitations to crop production. Our results show that elevated salinity concentrations in surface waters mainly occur in peak irrigation regions as irrigated agriculture is not only the most relevant water use sector contributing to water abstractions, but also the dominant source of salinity pollution. Additionally, large metropolitan regions are initially loading hotspots and pollution, too, and prevention becomes important as point sources are dependent on sewer connection rates and treatment levels. In conclusion, this study provides a detailed picture of the spatial and temporal distribution of salinity pollution and identifies hotspot areas as well as the dominant sources. Furthermore, impacts of water quality degradation on agricultural production and food security are quantified, which aim for a better understanding of the risks for food security caused by water quality impairment.
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Lallias, Delphine; Hiddink, Jan G; Fonseca, Vera G; Gaspar, John M; Sung, Way; Neill, Simon P; Barnes, Natalie; Ferrero, Tim; Hall, Neil; Lambshead, P John D; Packer, Margaret; Thomas, W Kelley; Creer, Simon
2015-01-01
Assessing how natural environmental drivers affect biodiversity underpins our understanding of the relationships between complex biotic and ecological factors in natural ecosystems. Of all ecosystems, anthropogenically important estuaries represent a ‘melting pot' of environmental stressors, typified by extreme salinity variations and associated biological complexity. Although existing models attempt to predict macroorganismal diversity over estuarine salinity gradients, attempts to model microbial biodiversity are limited for eukaryotes. Although diatoms commonly feature as bioindicator species, additional microbial eukaryotes represent a huge resource for assessing ecosystem health. Of these, meiofaunal communities may represent the optimal compromise between functional diversity that can be assessed using morphology and phenotype–environment interactions as compared with smaller life fractions. Here, using 454 Roche sequencing of the 18S nSSU barcode we investigate which of the local natural drivers are most strongly associated with microbial metazoan and sampled protist diversity across the full salinity gradient of the estuarine ecosystem. In order to investigate potential variation at the ecosystem scale, we compare two geographically proximate estuaries (Thames and Mersey, UK) with contrasting histories of anthropogenic stress. The data show that although community turnover is likely to be predictable, taxa are likely to respond to different environmental drivers and, in particular, hydrodynamics, salinity range and granulometry, according to varied life-history characteristics. At the ecosystem level, communities exhibited patterns of estuary-specific similarity within different salinity range habitats, highlighting the environmental sequencing biomonitoring potential of meiofauna, dispersal effects or both. PMID:25423027
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Eichele-Nelson, Jaclyn L; Wick, Abbey F; DeSutter, Thomas M; Harmon, Jason P
2017-08-01
Many environmental factors, including soil characteristics, are critical for plants, herbivorous arthropods, and their interactions. Despite increasing evidence that soil salinity drastically impacts plants, little is known about how salinity affects the herbivorous arthropod pests feeding on those plants. We investigated how soil salinity affects the twospotted spider mite (Tetranychus urticae Koch) feeding on corn (Zea mays L.) and soybean (Glycine max L.). We performed two greenhouse studies, one focusing on the impact of salinity on individual mite fecundity over a period of 3 d and the other focusing on population growth of T. urticae over 7 d. Both experiments were performed across varying salinity levels; electrical conductivity values ranged from 0.84 to 8.07 dS m-1. We also performed the 3-d fecundity experiment in the field, across naturally varying saline conditions. Overall, the twospotted spider mite performed better as salinity increased; both fecundity and population growth tended to have a positive linear correlation with salinity. These studies suggest that salinity can be important for herbivores, just as it is for plants. Moreover, the negative effects of soil salinity on crop plants in agroecosystems may be further compounded by a greater risk of pest problems. Salinity may be another important environmental stressor that can directly influence crop production while also indirectly influencing herbivorous pests. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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Sublethal salinity stress contributes to habitat limitation in an endangered estuarine fish.
Komoroske, Lisa M; Jeffries, Ken M; Connon, Richard E; Dexter, Jason; Hasenbein, Matthias; Verhille, Christine; Fangue, Nann A
2016-09-01
As global change alters multiple environmental conditions, predicting species' responses can be challenging without understanding how each environmental factor influences organismal performance. Approaches quantifying mechanistic relationships can greatly complement correlative field data, strengthening our abilities to forecast global change impacts. Substantial salinity increases are projected in the San Francisco Estuary, California, due to anthropogenic water diversion and climatic changes, where the critically endangered delta smelt (Hypomesus transpacificus) largely occurs in a low-salinity zone (LSZ), despite their ability to tolerate a much broader salinity range. In this study, we combined molecular and organismal measures to quantify the physiological mechanisms and sublethal responses involved in coping with salinity changes. Delta smelt utilize a suite of conserved molecular mechanisms to rapidly adjust their osmoregulatory physiology in response to salinity changes in estuarine environments. However, these responses can be energetically expensive, and delta smelt body condition was reduced at high salinities. Thus, acclimating to salinities outside the LSZ could impose energetic costs that constrain delta smelt's ability to exploit these habitats. By integrating data across biological levels, we provide key insight into the mechanistic relationships contributing to phenotypic plasticity and distribution limitations and advance the understanding of the molecular osmoregulatory responses in nonmodel estuarine fishes.
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Ecological drivers and habitat associations of estuarine bivalves
Tunberg, Björn G.; Johnston, Cora A.; Barshis, Daniel J.
2015-01-01
Community composition of the infaunal bivalve fauna of the St. Lucie Estuary and southern Indian River Lagoon, eastern Florida was sampled quarterly for 10 years as part of a long-term benthic monitoring program. A total of 38,514 bivalves of 137 taxa were collected and identified. We utilized this data, along with sediment samples and environmental measurements gathered concurrently, to assess the community composition, distribution, and ecological drivers of the infaunal bivalves of this estuary system. Salinity had the strongest influence on bivalve assemblage across the 15 sites, superseding the influences of sediment type, water turbidity, temperature and other environmental parameters. The greatest diversity was found in higher salinity euhaline sites, while the greatest abundance of individual bivalves was found in medium salinity mixohaline sites, the lowest diversity and abundances were found in the low salinity oligohaline sites, demonstrating a strong positive association between salinity and diversity/abundance. Water management decisions for the estuary should incorporate understanding of the role of salinity on bivalve diversity, abundance, and ecosystem function. PMID:26587338
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Ecological drivers and habitat associations of estuarine bivalves.
McKeon, C Seabird; Tunberg, Björn G; Johnston, Cora A; Barshis, Daniel J
2015-01-01
Community composition of the infaunal bivalve fauna of the St. Lucie Estuary and southern Indian River Lagoon, eastern Florida was sampled quarterly for 10 years as part of a long-term benthic monitoring program. A total of 38,514 bivalves of 137 taxa were collected and identified. We utilized this data, along with sediment samples and environmental measurements gathered concurrently, to assess the community composition, distribution, and ecological drivers of the infaunal bivalves of this estuary system. Salinity had the strongest influence on bivalve assemblage across the 15 sites, superseding the influences of sediment type, water turbidity, temperature and other environmental parameters. The greatest diversity was found in higher salinity euhaline sites, while the greatest abundance of individual bivalves was found in medium salinity mixohaline sites, the lowest diversity and abundances were found in the low salinity oligohaline sites, demonstrating a strong positive association between salinity and diversity/abundance. Water management decisions for the estuary should incorporate understanding of the role of salinity on bivalve diversity, abundance, and ecosystem function.
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NASA Astrophysics Data System (ADS)
Gong, Xu; Huang, Xuxiong; Wen, Wen
2018-03-01
Fertilised eggs of the devil stringer ( Inimicus japonicus) were incubated at different salinity levels (21, 25, 29, 33, and 37), and then the hatching performances, morphological parameters, and biochemical composition (protein, lipid and carbohydrate) of the larvae were assayed to determine the influence of salinity on the early development of I. japonicus. The tested salinity levels did not affect the times of hatching or mouth opening for yolk-sac larvae. However, the salinity significantly influenced the hatching and survival rates of open-mouthed larvae, as well as the morphology of yolk-sac larvae. The data indicated that 30.5 to 37.3 and 24.4 to 29.8 were suitable salinity ranges for the survival of embryos and larvae of I. japonicus, respectively. Larvae incubated at a salinity level of 29 had the greatest full lengths, and decreasing yolk volume was positively correlated with the environmental salinity. With increasing salinity, the individual dry weights of newly hatched larvae or open-mouthed larvae decreased significantly. Newly hatched larvae incubated at a salinity level of 29 had the greatest metabolic substrate contents and gross energy levels, while the openmouthed larvae's greatest values occurred at a salinity level of 25. Larvae incubated in the salinity range of 33 to 37 had the lowest nutritional reserves and energy values. Thus, the I. japonicus yolk-sac larvae acclimated more readily to the lower salinity level than the embryos, and higher salinity levels negatively influenced larval growth and development. In conclusion, the environmental salinity level should be maintained at 29-33 during embryogenesis and at 25-29 during early larval development for this species. Our results can be used to provide optimum aquaculture conditions for the early larval development of I. japonicus.
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NASA Astrophysics Data System (ADS)
Gong, Xu; Huang, Xuxiong; Wen, Wen
2017-05-01
Fertilised eggs of the devil stringer (Inimicus japonicus) were incubated at different salinity levels (21, 25, 29, 33, and 37), and then the hatching performances, morphological parameters, and biochemical composition (protein, lipid and carbohydrate) of the larvae were assayed to determine the influence of salinity on the early development of I. japonicus. The tested salinity levels did not affect the times of hatching or mouth opening for yolk-sac larvae. However, the salinity significantly influenced the hatching and survival rates of open-mouthed larvae, as well as the morphology of yolk-sac larvae. The data indicated that 30.5 to 37.3 and 24.4 to 29.8 were suitable salinity ranges for the survival of embryos and larvae of I. japonicus, respectively. Larvae incubated at a salinity level of 29 had the greatest full lengths, and decreasing yolk volume was positively correlated with the environmental salinity. With increasing salinity, the individual dry weights of newly hatched larvae or open-mouthed larvae decreased significantly. Newly hatched larvae incubated at a salinity level of 29 had the greatest metabolic substrate contents and gross energy levels, while the openmouthed larvae's greatest values occurred at a salinity level of 25. Larvae incubated in the salinity range of 33 to 37 had the lowest nutritional reserves and energy values. Thus, the I. japonicus yolk-sac larvae acclimated more readily to the lower salinity level than the embryos, and higher salinity levels negatively influenced larval growth and development. In conclusion, the environmental salinity level should be maintained at 29-33 during embryogenesis and at 25-29 during early larval development for this species. Our results can be used to provide optimum aquaculture conditions for the early larval development of I. japonicus.
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NASA Astrophysics Data System (ADS)
Weiss, Gabriella M.; Pfannerstill, Eva Y.; Schouten, Stefan; Sinninghe Damsté, Jaap S.; van der Meer, Marcel T. J.
2017-12-01
Over the last decade, hydrogen isotopes of long-chain alkenones have been shown to be a promising proxy for reconstructing paleo sea surface salinity due to a strong hydrogen isotope fractionation response to salinity across different environmental conditions. However, to date, the decoupling of the effects of alkalinity and salinity, parameters that co-vary in the surface ocean, on hydrogen isotope fractionation of alkenones has not been assessed. Furthermore, as the alkenone-producing haptophyte, Emiliania huxleyi, is known to grow in large blooms under high light intensities, the effect of salinity on hydrogen isotope fractionation under these high irradiances is important to constrain before using δDC37 to reconstruct paleosalinity. Batch cultures of the marine haptophyte E. huxleyi strain CCMP 1516 were grown to investigate the hydrogen isotope fractionation response to salinity at high light intensity and independently assess the effects of salinity and alkalinity under low-light conditions. Our results suggest that alkalinity does not significantly influence hydrogen isotope fractionation of alkenones, but salinity does have a strong effect. Additionally, no significant difference was observed between the fractionation responses to salinity recorded in alkenones grown under both high- and low-light conditions. Comparison with previous studies suggests that the fractionation response to salinity in culture is similar under different environmental conditions, strengthening the use of hydrogen isotope fractionation as a paleosalinity proxy.
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Environmental stressors such as salinity may affect plant germination and early growth, eventually impacting the distribution and abundance of more mature individuals. In a lab study we evaluated germination sensitivity to salinity in 13 tidal wetland species found in the Pacific...
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Sauco, Sebastián; Gómez, Julio; Barboza, Francisco R.; Lercari, Diego; Defeo, Omar
2013-01-01
Environmental gradients and wastewater discharges produce aggregated effects on marine populations, obscuring the detection of human impact. Classical assessment methods do not include environmental effects in toxicity tests designs, which could lead to incorrect conclusions. We proposed a modified Whole Effluent Toxicity test (mWET) that includes environmental gradients in addition to effluent dilutions, together with the application of Generalized Linear Mixed Models (GLMM) to assess and decouple those effects. We tested this approach, analyzing the lethal effects of wastewater on a marine sandy beach bivalve affected by an artificial canal freshwater discharge used for rice crops irrigation. To this end, we compared bivalve mortality between canal water dilutions (CWd) and salinity controls (SC: without canal water). CWd were prepared by diluting the water effluent (sampled during the pesticide application period) with artificial marine water. The salinity gradient was included in the design by achieving the same final salinities in both CWd and SC, allowing us to account for the effects of salinity by including this variable as a random factor in the GLMM. Our approach detected significantly higher mortalities in CWd, indicating potential toxic effects of the effluent discharge. mWET represents an improvement over the internationally standardized WET tests, since it considers environmental variability and uses appropriate statistical analyses. PMID:23755304
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Long, Jeremy D.; Porturas, Laura D.
2014-01-01
Plant communities are disturbed by several stressors and they are expected to be further impacted by increasing anthropogenic stress. The consequences of these stressors will depend, in part, upon the ability of plants to compensate for herbivory. Previous studies found that herbivore impacts on plants can vary from negative to positive because of environmental control of plant compensatory responses, a.k.a. the Compensatory Continuum Hypothesis. While these influential studies enhanced our appreciation of the dynamic nature of plant-herbivore interactions, they largely focused on the impact of resource limitation. This bias limits our ability to predict how other environmental factors will shape the impact of herbivory. We examined the role of salinity stress on herbivory of salt marsh cordgrass, Spartina foliosa, by an herbivore previously hypothesized to influence the success of restoration projects (the scale insect, Haliaspis spartinae). Using a combination of field and mesocosm manipulations of scales and salinity, we measured how these factors affected Spartina growth and timing of senescence. In mesocosm studies, Spartina overcompensated for herbivory by growing taller shoots at low salinities but the impact of scales on plants switched from positive to neutral with increasing salinity stress. In field studies of intermediate salinities, scales reduced Spartina growth and increased the rate of senescence. Experimental salinity additions at this field site returned the impact of scales to neutral. Because salinity decreased scale densities, the switch in impact of scales on Spartina with increasing salinity was not simply a linear function of scale abundance. Thus, the impact of scales on primary production depended strongly upon environmental context because intermediate salinity stress prevented plant compensatory responses to herbivory. Understanding this context-dependency will be required if we are going to successfully predict the success of restoration efforts and the ecological consequences of anthropogenic disturbances. PMID:25310475
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δDalkenone as a paleosalinity indicator
NASA Astrophysics Data System (ADS)
Weiss, G.; S Sinninghe Damsté, J.; Schouten, S.; van der Meer, M.
2017-12-01
The stable hydrogen isotope ratio of C37 alkenones (δDC37) produced by haptophyte algae has been investigated as a means to track hydrologic shifts and reconstruct paleosalinity of the surface ocean1,2,3. For the most part, research has focused on culture experiments and few environmental settings have been explored. In culture, the hydrogen isotope fractionation factor between alkenones and growth water, referred to as αC37, has been proposed as a proxy for sea surface salinity, due to a significant relationship between αC37 and salinity observed under a number of different environmental factors, such as temperature and growth rate1,2. Here we present a compilation of δDC37 measured on marine surface sediments along transects from the Skaggerak into the Baltic Sea, the south west North Atlantic, and the Mediterranean, covering a salinity range from 7-39. Based on our results, we propose to use δDC37 to reconstruct salinity, instead of αC37, because it shows a more significant relationship to salinity in environmental settings. 1Sachs et al, 2016. GCA 189, 96-109. 2Schouten et al., 2006. Biogeosciences 3, 113-119. 3Simon et al., 2015. Paleoceanography 30, 1318-1327
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Lei, Fan; Kheir, Michael M.; Wang, Xin-Pei; Chai, Yu-Shuang; Yuan, Zhi-Yi; Lu, Xi; Xing, Dong-Ming; Du, Feng; Du, Li-Jun
2013-01-01
The purpose of this study was to assess the effects of berberine (BBR) on thermoregulation in mice exposed to hot (40°C) and cold (4°C) environmental conditions. Four groups of mice were assembled with three different dosages of BBR (0.2, 0.4, and 0.8 mg/kg) and normal saline (control). In room temperature, our largest dosage of BBR (0.8 mg/kg) can reduce rectal temperatures (Tc) of normal mice. In hot conditions, BBR can antagonize the increasing core body temperature and inhibit the expression of HSP70 and TNFα in mice; conversely, in cold conditions, BBR can antagonize the decreasing core body temperature and enhance the expression of TRPM8. This study demonstrates the dual ability of BBR in maintaining thermal balance, which is of great relevance to the regulation of HSP70, TNFα and TRPM8. PMID:23335996
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Salinity-oriented environmental flows for keystone species in the Modaomen Estuary, China
NASA Astrophysics Data System (ADS)
Zhang, Menglu; Cui, Baoshan; Zhang, Zhiming; Jiang, Xuelian
2017-12-01
Rapid development and urbanization in recent years have contributed to a reduction in freshwater discharge and intensified saltwater intrusion in the Pearl River Delta. This comprises a significant threat to potable water supplies and overall estuary ecosystem health. In this study, the environmental flows of the Modaomen Estuary, one of the estuaries of the Pearl River Delta in China, were determined based on the salinity demand of keystone species and the linear relationship between river discharge and estuarine salinity. The estimated minimum and optimal annual environmental flows in the Modaomen Estuary were 116.8 × 109 m3 and 273.8 × 109 m3, respectively, representing 59.3% and 139.0% of the natural runoff. Water quality assessments in recent years indicate that the environmental flows have not been satisfied most of the time, particularly the optimal environmental flow, despite implementation of various water regulations since 2005. Therefore, water regulations and wetland network recoveries based on rational environmental flows should be implemented to alleviate saltwater intrusion and for the creation of an ideal estuarine habitat.
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Metrological challenges for measurements of key climatological observables Part 2: oceanic salinity
NASA Astrophysics Data System (ADS)
Pawlowicz, R.; Feistel, R.; McDougall, T. J.; Ridout, P.; Seitz, S.; Wolf, H.
2016-02-01
Salinity is a key variable in the modelling and observation of ocean circulation and ocean-atmosphere fluxes of heat and water. In this paper, we examine the climatological relevance of ocean salinity, noting fundamental deficiencies in the definition of this key observable, and its lack of a secure foundation in the International System of Units, the SI. The metrological history of salinity is reviewed, problems with its current definitions and measurement practices are analysed, and options for future improvements are discussed in conjunction with the recent seawater standard TEOS-10.
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The role of North African rivers in driving Mediterranean-Atlantic exchange
NASA Astrophysics Data System (ADS)
Flecker, Rachel; Marzocchi, Alice; van der Schee, Marlies; Meijer, Paul; Lofi, Johanna; Lunt, Dan
2014-05-01
The main driver for exchange through the Gibraltar Strait today is the density contrast between Mediterranean and Atlantic water. Mediterranean water is more saline than Atlantic water because the amount of water the Mediterranean loses through evaporation exceeds both precipitation and freshwater input from rivers. This means it has a negative hydrologic budget. In the Late Miocene however, a very large river known as the Esohabi River drained across North Africa and had its mouth in the Gulf of Sirt. This river was sourced in palaeo-Lake Chad and was strongly influenced by precession-driven monsoonal rainfall. Multiple General Circulation Model simulations through a single precessional cycle indicate that river water may only have reached the Mediterranean in significant quantities in summer during particular orbital configurations e.g. precession minima combined with eccentricity maxima. However, during high amplitude eccentricity maxima, the volume of water supplied through the Esohabi and Nile rivers may have been sufficient to switch the hydrologic budget from negative to positive. In doing so, the fresh water supply should have reduced the salinity of the Mediterranean and consequently the density contrast with adjacent Atlantic water leading to a reduction in exchange. In this presentation we explore the evidence for the timing and nature of freshwater input to the Mediterranean from North Africa. We also consider how relevant this freshwater flux may be in determining some of the major environmental and sedimentological changes in the Late Miocene to early Pliocene including some of the salinity changes that occurred during the Messinian Salinity Crisis.
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Tills, Oliver; Bitterli, Tabitha; Culverhouse, Phil; Spicer, John I; Rundle, Simon
2013-02-01
Motion analysis is one of the tools available to biologists to extract biologically relevant information from image datasets and has been applied to a diverse range of organisms. The application of motion analysis during early development presents a challenge, as embryos often exhibit complex, subtle and diverse movement patterns. A method of motion analysis able to holistically quantify complex embryonic movements could be a powerful tool for fields such as toxicology and developmental biology to investigate whole organism stress responses. Here we assessed whether motion analysis could be used to distinguish the effects of stressors on three early developmental stages of each of three species: (i) the zebrafish Danio rerio (stages 19 h, 21.5 h and 33 h exposed to 1.5% ethanol and a salinity of 5); (ii) the African clawed toad Xenopus laevis (stages 24, 32 and 34 exposed to a salinity of 20); and iii) the pond snail Radix balthica (stages E3, E4, E6, E9 and E11 exposed to salinities of 5, 10 and 15). Image sequences were analysed using Sparse Optic Flow and the resultant frame-to-frame motion parameters were analysed using Discrete Fourier Transform to quantify the distribution of energy at different frequencies. This spectral frequency dataset was then used to construct a Bray-Curtis similarity matrix and differences in movement patterns between embryos in this matrix were tested for using ANOSIM. Spectral frequency analysis of these motion parameters was able to distinguish stage-specific effects of environmental stressors in most cases, including Xenopus laevis at stages 24, 32 and 34 exposed to a salinity of 20, Danio rerio at 33 hpf exposed to 1.5% ethanol, and Radix balthica at stages E4, E9 and E11 exposed to salinities of 5, 10 and 15. This technique was better able to distinguish embryos exposed to stressors than analysis of manual quantification of movement and within species distinguished most of the developmental stages studied in the control treatments. This innovative use of motion analysis incorporates data quantifying embryonic movements at a range of frequencies and so provides an holistic analysis of an embryo's movement patterns. This technique has potential applications for quantifying embryonic responses to environmental stressors such as exposure to pharmaceuticals or pollutants, and also as an automated tool for developmental staging of embryos.
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Regional-scale Assessment of Soil Salinity in the Red River Valley Using Multi-year MODIS EVI
USDA-ARS?s Scientific Manuscript database
The ability to inventory and map soil salinity at regional scales remains a significant challenge to soil, environmental, and natural resource scientists. Previous attempts to use satellite or aerial imagery to assess and map soil salinity have resulted in limited success due, in part, to the inabi...
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USDA-ARS?s Scientific Manuscript database
Salinization is one important factor contributing to land degradation, which affects agricultural production and environmental quality, especially in the West side of central California. When salinization is combined with a natural contamination of trace elements (i.e., Se and B) in arid and semi-ar...
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Salinity dependent Na+-K+ATPase activity in gills of the euryhaline crab Chasmagnathus granulata.
Schleich, C E; Goldemberg, L A; López Mañanes, A A
2001-09-01
The occurrence and response of Na+-K+ATPase specific activity to environmental salinity changes were studied in gill extracts of all of the gills of the euryhaline crab Chasmagnathus granulata from Mar Chiquita coastal lagoon (Buenos Aires Province, Argentina). All of the gills exhibited a salinity dependent Na+-K+ATPase activity, although the pattern of response to environmental salinity was different among gills. As described in other euryhaline crabs highest Na+-K+ATPase specific activity was found in posterior gills (6 to 8), which, with exception of gill 6, increased upon acclimation to reduced salinity. However, a high increase of activity also occurred in anterior gills (1 to 5) in diluted media. Furthermore, both short and long term differential changes of Na+-K+ATPase activity occurred among the gills after the transfer of crabs to reduced salinity. The fact that variations of Na+-K+ATPase activity in the gills were concomitant with the transition from osmoconformity to ionoregulation suggests that this enzyme is a component of the branchial ionoregulatory mechanisms at the biochemical level in this crab.
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An overview of the Central Queensland University self-contained evapotranspiration beds.
Kele, B; Midmore, D J; Harrower, K; McKennariey, B J; Hood, B
2005-01-01
The Central Queensland University (CQU) has championed a self-contained concrete lined evapotranspiration channel. Any non-transpired effluent returns to a holding tank and is recirculated through the evapotranspiration channel until it is used. This paper examines the results from the Rockhampton trial site. Nutrient ions in the effluent were quantified over time and found not to accumulate in solution. Microbial analysis of the treated effluent was performed and was found to be within the ranges required by the relevant legislative codes. Citrus fruit grown in the evapotranspiration channel were sampled and no elevated levels of faecal coliforms were recorded. Macronutrients and micronutrients of the soil in the channels were measured over a 5-year period. No toxic accumulations or nutrient deficiencies in the soil occurred. Levels of salinity and sodicity in the evapotranspiration channel soil were quantified. Salinity rose slightly, as did sodium. Concentrations of salts and sodium did not reach unsustainable levels. The aim of the trial was to develop an on-site treatment and reuse system that is sustainable and protects public and environmental health.
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NASA Astrophysics Data System (ADS)
Xu, Naizheng; Gong, Jianshi; Yang, Guoqiang
2018-01-01
Hydrochemical analysis and environmental isotopic tracing are successfully applied to study groundwater evolution processes. Located in eastern China, the Jiangsu Coastal Plain is characterized by an extensively exploited deep groundwater system, and groundwater salinization has become the primary water environmental problem. This paper provides a case study on the use of a hydrochemical and environmental isotopic approach to assess possible mixing and evolution processes at Yoco Port, Jiangsu Province, China. Hydrochemical and isotopic patterns of deep groundwater allow one to distinguish different origins in deep water systems. HCO3- is the dominant anion in the freshwater samples, whereas Na+ and Cl- are the dominant major ions in the saline samples. According to δ18O, δ2H and 14C dating, the fresh water is derived from precipitation under a colder climate during the Glacial Maximum (Dali Glacial), while the saline groundwater is influenced by glacial-interglacial cycles during the Holocene Hypsithermal. The δ18O, δ2H and 3H data confirm that deep groundwater in some boreholes is mixed with overlying saline water. The deep groundwater reservoir can be divided into a saline water sector and a fresh water sector, and each show distinct hydrochemical and isotopic compositions. The saline groundwater found in the deep aquifer cannot be associated with present seawater intrusion. Since the Last Glacial Maximum in the Late Pleistocene, the deep groundwater flow system has evolved to its current status with the decrease in ice cover and the rising of sea level. However, the hydraulic connection is strengthened by continuous overexploitation, and deep groundwater is mixed with shallow groundwater at some points.
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Xu, Naizheng; Gong, Jianshi; Yang, Guoqiang
2018-01-01
Hydrochemical analysis and environmental isotopic tracing are successfully applied to study groundwater evolution processes. Located in eastern China, the Jiangsu Coastal Plain is characterized by an extensively exploited deep groundwater system, and groundwater salinization has become the primary water environmental problem. This paper provides a case study on the use of a hydrochemical and environmental isotopic approach to assess possible mixing and evolution processes at Yoco Port, Jiangsu Province, China. Hydrochemical and isotopic patterns of deep groundwater allow one to distinguish different origins in deep water systems. HCO 3 - is the dominant anion in the freshwater samples, whereas Na + and Cl - are the dominant major ions in the saline samples. According to δ 18 O, δ 2 H and 14 C dating, the fresh water is derived from precipitation under a colder climate during the Glacial Maximum (Dali Glacial), while the saline groundwater is influenced by glacial-interglacial cycles during the Holocene Hypsithermal. The δ 18 O, δ 2 H and 3 H data confirm that deep groundwater in some boreholes is mixed with overlying saline water. The deep groundwater reservoir can be divided into a saline water sector and a fresh water sector, and each show distinct hydrochemical and isotopic compositions. The saline groundwater found in the deep aquifer cannot be associated with present seawater intrusion. Since the Last Glacial Maximum in the Late Pleistocene, the deep groundwater flow system has evolved to its current status with the decrease in ice cover and the rising of sea level. However, the hydraulic connection is strengthened by continuous overexploitation, and deep groundwater is mixed with shallow groundwater at some points. Copyright © 2017 Elsevier B.V. All rights reserved.
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NASA Astrophysics Data System (ADS)
Nche-Fambo, F. A.; Scharler, U. M.; Tirok, K.
2015-06-01
In South African estuaries, there is no knowledge on the resilience and variability in phytoplankton communities under conditions of hypersalinity, extended droughts and reverse salinity gradients. Phytoplankton composition, abundance and biomass vary with changes in environmental variables and taxa richness declines specifically under hypersaline conditions. This research thus investigated the phytoplankton community composition, its resilience and variability under highly variable and extreme environmental conditions in an estuarine lake system (Lake St. Lucia, South Africa) over one year. The lake system was characterised by a reverse salinity gradient with hypersalinity furthest from the estuarine inlet during the study period. During this study, 78 taxa were recorded: 56 diatoms, eight green algae, one cryptophyte, seven cyanobacteria and six dinoflagellates. Taxon variability and resilience depended on their ability to tolerate high salinities. Consequently, the phytoplankton communities as well as total abundance and biomass differed along the salinity gradient and over time with salinity as the main determinant. Cyanobacteria were dominant in hypersaline conditions, dinoflagellates in marine-brackish salinities, green algae and cryptophytes in lower salinities (brackish) and diatoms were abundant in marine-brackish salinities but survived in hypersaline conditions. Total abundance and biomass ranged from 3.66 × 103 to 1.11 × 109 Cells/L and 1.21 × 106 to 1.46 × 1010 pgC/L respectively, with the highest values observed under hypersaline conditions. Therefore, even under highly variable, extreme environmental conditions and hypersalinity the phytoplankton community as a whole was resilient enough to maintain a relatively high biomass throughout the study period. The resilience of few dominant taxa, such as Cyanothece, Spirulina, Protoperidinium and Nitzschia and the dominance of other common genera such as Chlamydomonas, Chroomonas, Navicula, Gyrosigma, Oxyrrhis, and Prorocentrum, provided the carbon at the base of the food web in the system and showed that even during the extended period of drought, a foundation for productivity can be provided for once conditions improve.
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Zhong, Zhi-Ping; Liu, Ying; Miao, Li-Li; Wang, Fang; Chu, Li-Min; Wang, Jia-Li
2016-01-01
The prokaryotic community composition and diversity and the distribution patterns at various taxonomic levels across gradients of salinity and physiochemical properties in the surface waters of seven plateau lakes in the Qaidam Basin, Tibetan Plateau, were evaluated using Illumina MiSeq sequencing. These lakes included Lakes Keluke (salinity, <1 g/liter), Qing (salinity, 5.5 to 6.6 g/liter), Tuosu (salinity, 24 to 35 g/liter), Dasugan (salinity, 30 to 33 g/liter), Gahai (salinity, 92 to 96 g/liter), Xiaochaidan (salinity, 94 to 99 g/liter), and Gasikule (salinity, 317 to 344 g/liter). The communities were dominated by Bacteria in lakes with salinities of <100 g/liter and by Archaea in Lake Gasikule. The clades At12OctB3 and Salinibacter, previously reported only in hypersaline environments, were found in a hyposaline lake (salinity, 5.5 to 6.6 g/liter) at an abundance of ∼1.0%, indicating their ecological plasticity. Salinity and the concentrations of the chemical ions whose concentrations covary with salinity (Mg2+, K+, Cl−, Na+, SO42−, and Ca2+) were found to be the primary environmental factors that directly or indirectly determined the composition and diversity at the level of individual clades as well as entire prokaryotic communities. The distribution patterns of two phyla, five classes, five orders, five families, and three genera were well predicted by salinity. The variation of the prokaryotic community structure also significantly correlated with the dissolved oxygen concentration, pH, the total nitrogen concentration, and the PO43− concentration. Such correlations varied depending on the taxonomic level, demonstrating the importance of comprehensive correlation analyses at various taxonomic levels in evaluating the effects of environmental variable factors on prokaryotic community structures. Our findings clarify the distribution patterns of the prokaryotic community composition in plateau lakes at the levels of individual clades as well as whole communities along gradients of salinity and ionic concentrations. PMID:26746713
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NASA Astrophysics Data System (ADS)
Bi, R.; Liu, H.
2016-02-01
Understanding how biological components respond to environmental changes could be insightful to predict ecosystem trajectories under different climate scenarios. Zooplankton are key components of marine ecosystems and changes in their dynamics could have major impact on ecosystem structure. We developed an individual-based model of a common coastal calanoid copepod Acartia tonsa to examine how environmental factors affect zooplankton population dynamics and explore the role of individual variability in sustaining population under various environmental conditions consisting of temperature, food concentration and salinity. Total abundance, egg production and proportion of survival were used to measure population success. Results suggested population benefits from high level of individual variability under extreme environmental conditions including unfavorable temperature, salinity, as well as low food concentration, and selection on fast-growers becomes stronger with increasing individual variability and increasing environmental stress. Multiple regression analysis showed that temperature, food concentration, salinity and individual variability have significant effects on survival of A. tonsa population. These results suggest that environmental factors have great influence on zooplankton population, and individual variability has important implications for population survivability under unfavorable conditions. Given that marine ecosystems are at risk from drastic environmental changes, understanding how individual variability sustains populations could increase our capability to predict population dynamics in a changing environment.
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In situ release rates of Cu and Zn from commercial antifouling paints at different salinities.
Lagerström, Maria; Lindgren, J Fredrik; Holmqvist, Albin; Dahlström, Mia; Ytreberg, Erik
2018-02-01
Antifouling paints are environmentally risk assessed based on their biocidal release rates to the water phase. In situ release rates of copper (Cu) and zinc (Zn) were derived for five commercial paints in two recreational marinas with different salinities (5 and 14 PSU) using an X-Ray Fluorescence spectrometer (XRF). Salinity was found to significantly affect the Cu release, with twice the amount of Cu released at the higher salinity, while its influence on the Zn release was paint-specific. Site-specific release rates for water bodies with salinity gradients, e.g. the Baltic Sea, are therefore necessary for more realistic risk assessments of antifouling paints. Furthermore, the in situ release rates were up to 8 times higher than those generated using standardized laboratory or calculation methods. The environmental risk assessment repeated with the field release rates concludes that it is questionable whether the studied products should be allowed on the Swedish market. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.
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Kang, Sung-Ryong; King, Sammy L.
2013-01-01
Hydrologic connectivity and environmental variation can influence nekton assemblages in coastal ecosystems. We evaluated the effects of hydrologic connectivity (permanently connected pond: PCP; temporary connected pond: TCP), salinity, vegetation coverage, water depth and other environmental variables on seasonal nekton assemblages in freshwater, brackish, and saline marshes of the Chenier Plain, Louisiana, USA. We hypothesize that 1) nekton assemblages in PCPs have higher metrics (density, biomass, assemblage similarity) than TCPs within all marsh types and 2) no nekton species would be dominant across all marsh types. In throw traps, freshwater PCPs in Fall (36.0 ± 1.90) and Winter 2009 (43.2 ± 22.36) supported greater biomass than freshwater TCPs (Fall 2009: 9.1 ± 4.65; Winter 2009: 8.3 ± 3.42). In minnow traps, saline TCPs (5.9 ± 0.85) in Spring 2009 had higher catch per unit effort than saline PCPs (0.7 ± 0.67). Our data only partially support our first hypothesis as freshwater marsh PCPs had greater assemblage similarity than TCPs. As predicted by our second hypothesis, no nekton species dominated across all marsh types. Nekton assemblages were structured by individual species responses to the salinity gradient as well as pond habitat attributes (submerged aquatic vegetation coverage, dissolved oxygen, hydrologic connectivity).
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ERIC Educational Resources Information Center
Schmitt, Walter R.
1987-01-01
Discussed are the costs of deriving energy from the earth's natural reserves of salt. Argues that, as fossil fuel supplies become more depleted in the future, the environmental advantages of salinity power may prove to warrant its exploitation. (TW)
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Czechowski, Paul; White, Duanne; Clarke, Laurence; McKay, Alan; Cooper, Alan; Stevens, Mark I
2016-12-01
The potential impact of environmental change on terrestrial Antarctic ecosystems can be explored by inspecting biodiversity patterns across large-scale gradients. Unfortunately, morphology-based surveys of Antarctic invertebrates are time-consuming and limited by the cryptic nature of many taxa. We used biodiversity information derived from high-throughput sequencing (HTS) to elucidate the relationship between soil properties and invertebrate biodiversity in the Prince Charles Mountains, East Antarctica. Across 136 analysed soil samples collected from Mount Menzies, Mawson Escarpment and Lake Terrasovoje, we found invertebrate distribution in the Prince Charles Mountains significantly influenced by soil salinity and/or sulfur content. Phyla Tardigrada and Arachnida occurred predominantly in low-salinity substrates with abundant nutrients, whereas Bdelloidea (Rotifera) and Chromadorea (Nematoda) were more common in highly saline substrates. A significant correlation between invertebrate occurrence, soil salinity and time since deglaciation indicates that terrain age indirectly influences Antarctic terrestrial biodiversity, with more recently deglaciated areas supporting greater diversity. Our study demonstrates the value of HTS metabarcoding to investigate environmental constraints on inconspicuous soil biodiversity across large spatial scales.
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White, Duanne; Clarke, Laurence; McKay, Alan; Cooper, Alan; Stevens, Mark I.
2016-01-01
The potential impact of environmental change on terrestrial Antarctic ecosystems can be explored by inspecting biodiversity patterns across large-scale gradients. Unfortunately, morphology-based surveys of Antarctic invertebrates are time-consuming and limited by the cryptic nature of many taxa. We used biodiversity information derived from high-throughput sequencing (HTS) to elucidate the relationship between soil properties and invertebrate biodiversity in the Prince Charles Mountains, East Antarctica. Across 136 analysed soil samples collected from Mount Menzies, Mawson Escarpment and Lake Terrasovoje, we found invertebrate distribution in the Prince Charles Mountains significantly influenced by soil salinity and/or sulfur content. Phyla Tardigrada and Arachnida occurred predominantly in low-salinity substrates with abundant nutrients, whereas Bdelloidea (Rotifera) and Chromadorea (Nematoda) were more common in highly saline substrates. A significant correlation between invertebrate occurrence, soil salinity and time since deglaciation indicates that terrain age indirectly influences Antarctic terrestrial biodiversity, with more recently deglaciated areas supporting greater diversity. Our study demonstrates the value of HTS metabarcoding to investigate environmental constraints on inconspicuous soil biodiversity across large spatial scales. PMID:28083092
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Urzúa, Ángel; Urbina, Mauricio A
2017-08-01
The estuarine crab Hemigrapsus crenulatus is a key benthic species of estuarine and intertidal ecosystems of the South Pacific, habitats that experience wide fluctuations in salinity. The physiological strategies that allow this crab to thrive under variable salinities, and how they change during the benthic stages of their life cycle, were evaluated under laboratory conditions. Oxygen consumption, ammonia excretion and the regulatory capacity of Na + through the normal range of environmental salinities (i.e. 5, 10, 15, 20, 25, 30) were evaluated in three size classes, ranging from juveniles to adults. In all sizes, the oxygen consumption, ammonia excretion and regulatory capacity of Na + decreased as salinity increased, with the highest values at 5 and the lowest values at 30 salinity. Bigger crabs showed a higher capacity to regulate Na + , as well as higher respiration and excretion rates compared to smaller crabs, suggesting that they are better equipped to exploit areas of the estuary with low salinity. Regardless of its size, H. crenulatus is a strong hyper regulator in diluted media (i.e. 5-20) while a conformer at salinities higher than 20. The regulatory capacity of Na + was positively related with oxygen consumption and ammonia excretion rates. These relationships between sodium regulation, respiration and excretion are interpreted as adaptive physiological mechanisms that allow H. crenulatus to maintain the osmotic and bioenergetic balance over a wide range of environmental salinities. Copyright © 2017 Elsevier Inc. All rights reserved.
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NASA Astrophysics Data System (ADS)
Masoud, Alaa A.; El-Horiny, Mohamed M.; Atwia, Mohamed G.; Gemail, Khaled S.; Koike, Katsuaki
2018-06-01
Salinization of groundwater and soil resources has long been a serious environmental hazard in arid regions. This study was conducted to investigate and document the factors controlling such salinization and their inter-relationships in the Dakhla Oasis (Egypt). To accomplish this, 60 groundwater samples and 31 soil samples were collected in February 2014. Factor analysis (FA) and hierarchical cluster analysis (HCA) were integrated with geostatistical analyses to characterize the chemical properties of groundwater and soil and their spatial patterns, identify the factors controlling the pattern variability, and clarify the salinization mechanism. Groundwater quality standards revealed emergence of salinization (av. 885.8 mg/L) and extreme occurrences of Fe2+ (av. 17.22 mg/L) and Mn2+ (av. 2.38 mg/L). Soils were highly salt-affected (av. 15.2 dS m-1) and slightly alkaline (av. pH = 7.7). Evaporation and ion-exchange processes governed the evolution of two main water types: Na-Cl (52%) and Ca-Mg-Cl (47%), respectively. Salinization leads the chemical variability of both resources. Distinctive patterns of slight salinization marked the northern part and intense salinization marked the middle and southern parts. Congruence in the resources clusters confirmed common geology, soil types, and urban and agricultural practices. Minimizing the environmental and socioeconomic impacts of the resources salinization urges the need for better understanding of the hydrochemical characteristics and prediction of quality changes.
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Shao, Hongbo; Ray, Jessica R; Jun, Young-Shin
2011-02-15
To ensure the viability of geologic CO2 sequestration (GCS), we need a holistic understanding of reactions at supercritical CO2 (scCO2)-saline water-rock interfaces and the environmental factors affecting these interactions. This research investigated the effects of salinity and the extent of water on the dissolution and surface morphological changes of phlogopite [KMg2.87Si3.07Al1.23O10(F,OH)2], a model clay mineral in potential GCS sites. Salinity enhanced the dissolution of phlogopite and affected the location, shape, size, and phase of secondary minerals. In low salinity solutions, nanoscale particles of secondary minerals formed much faster, and there were more nanoparticles than in high salinity solutions. The effect of water extent was investigated by comparing scCO2-H2O(g)-phlogopite and scCO2-H2O(l)-phlogopite interactions. Experimental results suggested that the presence of a thin water film adsorbed on the phlogopite surface caused the formation of dissolution pits and a surface coating of secondary mineral phases that could change the physical properties of rocks. These results provide new information for understanding reactions at scCO2-saline water-rock interfaces in deep saline aquifers and will help design secure and environmentally sustainable CO2 sequestration projects.
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NASA Astrophysics Data System (ADS)
Amoako Johnson, F.; Hutton, C.; Hornby, D.; Lazar, A.; Mukhopadhyay, A.
2014-12-01
Salinity intrusion is a major climate and human induced hazard in coastal deltaic regions resulting in substantial adverse effects on crop production. Impacts are exacerbated by intensified cyclones, sea level rise and storm surges. In this regard, many farmers in the populous Ganges-Brahmaputra Delta of Bangladesh have adopted saline shrimp (Bagda) farming with associated displacement of tenant farmers and potential long term damage to the soil through chemicals used to enhance shrimp production. Despite the impact of salinity intrusion on the environment and the commonly perceived effects of shrimp farming on poverty, there has not been any systematic study that examines the associative relationships between salinisation, shrimp farming and poverty in this delta region. Using the 2011 Bangladesh Population and Housing Census and 2010 LandSat remote sensing data this study examines the spatially explicit impact of salinization as well as saline and freshwater shrimp farming on poverty in the Delta, accounting for important environmental and socio-economic predictors. The findings shows that after accounting for important environmental and socioeconomic predictors, levels and intensities of salinization as well as the extent of saline and freshwater shrimp farming in a union are significantly associated with poverty. The results of the study demonstrate that increases in levels and intensities of salinity increases the probability of a union being in the poorest quintile. As such saline water shrimp farming has the potential to reduce poverty only at high intensities, whilst low levels of freshwater shrimp farming are associated with a reduction in poverty.
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Airborne Geophysical Surveys Applied to Hydrocarbon Resource Development Environmental Studies
NASA Astrophysics Data System (ADS)
Smith, B. D.; Ball, L. B.; Finn, C.; Kass, A.; Thamke, J.
2014-12-01
Application of airborne geophysical surveys ranges in scale from detailed site scale such as locating abandoned well casing and saline water plumes to landscape scale for mapping hydrogeologic frameworks pertinent to ground water and tectonic settings relevant to studies of induced seismicity. These topics are important in understanding possible effects of hydrocarbon development on the environment. In addition airborne geophysical surveys can be used in establishing baseline "snapshots", to provide information in beneficial uses of produced waters, and in mapping ground water resources for use in well development. The U.S. Geological Survey (USGS) has conducted airborne geophysical surveys over more than 20 years for applications in energy resource environmental studies. A majority of these surveys are airborne electromagnetic (AEM) surveys to map subsurface electrical conductivity related to plumes of saline waters and more recently to map hydrogeologic frameworks for ground water and plume migration. AEM surveys have been used in the Powder River Basin of Wyoming to characterize the near surface geologic framework for siting produced water disposal ponds and for beneficial utilization in subsurface drip irrigation. A recent AEM survey at the Fort Peck Reservation, Montana, was used to map both shallow plumes from brine pits and surface infrastructure sources and a deeper concealed saline water plume from a failed injection well. Other reported applications have been to map areas geologically favorable for shallow gas that could influence drilling location and design. Airborne magnetic methods have been used to image the location of undocumented abandoned well casings which can serve as conduits to the near surface for coproduced waters. They have also been used in conjunction with geologic framework studies to understand the possible relationships between tectonic features and induced earthquakes in the Raton Basin. Airborne gravity as well as developing deeper mapping AEM surveys could also be effectively used in mapping tectonic features. Airborne radiometric methods have not been routinely used in hydrocarbon environmental studies but might be useful in understanding the surficial distribution of deposits related to naturally occurring radioactive materials.
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Kube, S; Sokolowski, A; Jansen, J M; Schiedek, D
2007-08-01
The seasonal variability of the intracellular free amino acid (FAA) concentration was studied in 5 Macoma balthica populations and 7 Mytilus spp. populations along their European distribution. Because of the well known physiological role of FAA as organic osmolytes for salinity induced cell volume regulation in marine osmoconformers, FAA variations were compared in bivalve populations that were exposed to high vs. low intraannual salinity fluctuations. In general, seasonal FAA variations were more pronounced in M. balthica than in Mytilus spp. In both bivalve taxa from different locations in the Baltic Sea, highest FAA concentrations were found in autumn and winter and low FAA concentrations were measured in summer. Seasonal patterns were less pronounced in both taxa at locations with constant salinity conditions. In contrast to Baltic Sea populations, Atlantic and Mediterranean bivalves showed high FAA concentrations in summer and low values in winter, regardless of seasonal salinity fluctuations. Significant seasonal FAA variations at locations with constant salinity conditions showed that salinity appeared not to be the main factor in determining FAA concentrations. The seasonal patterns of the main FAA pool components, i.e. alanine, glycine and taurine, are discussed in the context of seasonal variations in environmental factors (salinity, temperature) and physiological state (glycogen content, reproductive stage).
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Salinity mobilization and transport from rangelands: assessment, recommendations, and knowledge gaps
USDA-ARS?s Scientific Manuscript database
The purpose of the salinity project is to improve the understanding of sources and transport mechanisms in rangeland catchments that deliver dissolved solids (salts) to streams within the Upper Colorado River Basin (UCRB) through a review of relevant literature on what is known about the impact of r...
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A Geology-Based Estimate of Connate Water Salinity Distribution
2014-09-01
poses serious environmental concerns if connate water is mobilized into shallow aquifers or surface water systems. Estimating the distribution of...groundwater flow and salinity transport near the Herbert Hoover Dike (HHD) surrounding Lake Okeechobee in Florida . The simulations were conducted using the...on the geologic configuration at equilibrium, and the horizontal salinity distribution is strongly linked to aquifer connectivity because
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Triki Fourati, Hela; Bouaziz, Moncef; Benzina, Mourad; Bouaziz, Samir
2017-04-01
Traditional surveying methods of soil properties over landscapes are dramatically cost and time-consuming. Thus, remote sensing is a proper choice for monitoring environmental problem. This research aims to study the effect of environmental factors on soil salinity and to map the spatial distribution of this salinity over the southern east part of Tunisia by means of remote sensing and geostatistical techniques. For this purpose, we used Advanced Spaceborne Thermal Emission and Reflection Radiometer data to depict geomorphological parameters: elevation, slope, plan curvature (PLC), profile curvature (PRC), and aspect. Pearson correlation between these parameters and soil electrical conductivity (EC soil ) showed that mainly slope and elevation affect the concentration of salt in soil. Moreover, spectral analysis illustrated the high potential of short-wave infrared (SWIR) bands to identify saline soils. To map soil salinity in southern Tunisia, ordinary kriging (OK), minimum distance (MD) classification, and simple regression (SR) were used. The findings showed that ordinary kriging technique provides the most reliable performances to identify and classify saline soils over the study area with a root mean square error of 1.83 and mean error of 0.018.
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Salinity and temperature tolerance of brown-marbled grouper Epinephelus fuscoguttatus.
Cheng, Sha-Yen; Chen, Chih-Sung; Chen, Jiann-Chu
2013-04-01
Grouper have to face varied environmental stressors as a result of drastic changes to water conditions during the storm season. We aimed to test the response of brown-marbled grouper to drastic and gradual changes in temperature and salinity to understand the grouper's basic stress response. The results can improve the culture of grouper. Brown-marbled grouper, Epinephelus fuscoguttatus (6.2 ± 0.8 g) were examined for temperature and salinity tolerances at nine different environmental regimes (10, 20, and 33 ‰ combined with 20, 26 and 32 °C), in which the fish were subjected to both gradual and sudden changes in temperature and salinity. The critical thermal maximum (50 % CTMAX) and the upper incipient lethal temperature (UILT) were in the ranges of 35.9-38.3 and 32.7-36.5 °C, respectively. The critical thermal minimum (50 % CTMIN) and the lower incipient lethal temperature (LILT) were in the ranges of 9.8-12.2 and 14.9-22.3 °C, respectively. The critical salinity maximum (50 % CSMAX) and the upper incipient lethal salinity (UILS) were in the ranges of 67.0-75.5 and 54.2-64.8 ‰, respectively. Fish at temperature of 20 °C and a salinity of 33 ‰ tolerated temperatures as low as 10 °C when the temperature was gradually decreased. Fish acclimated at salinities of 10-33 ‰ and a temperature of 32 °C tolerated salinities of as high as 75-79 ‰. All fish survived from accumulating salinity after acute transfer to 20, 10, 5, and 3 ‰. But all fish died while transferred to 0 ‰. Relationships among the UILT, LILT, 50 % CTMAX, 50 % CTMIN, UILS, 50 % CSMAX, salinity, and temperature were examined. The grouper's temperature and salinity tolerance elevated by increasing acclimation temperature and salinity. On the contrary, the grouper's temperature and salinity tolerance degraded by decreasing acclimation temperature and salinity. The tolerance of temperature and salinity on grouper in gradual changes were higher than in drastic changes.
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1972-01-01
in a considerable increase in the water salinity . Density stratification of the water is possible, the denser saline water forming the lower water...layer in the lake basin which causes anaerobic, toxic conditions. Salinity causes also an increase in flocculation and sedi- mentation of clay minerals...increased salin - ity of the lake water. Excessive water seepage in the fault zone intersecting the northern most part of the reservoir will probably
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Vu, Wendy T; Chang, Peter L; Moriuchi, Ken S; Friesen, Maren L
2015-04-01
Transgenerational plasticity provides phenotypic variation that contributes to adaptation. For plants, the timing of seed germination is critical for offspring survival in stressful environments, as germination timing can alter the environmental conditions a seedling experiences. Stored seed transcripts are important determinants of seed germination, but have not previously been linked with transgenerational plasticity of germination behavior. In this study we used RNAseq and growth chamber experiments of the model legume M. trucantula to test whether parental exposure to salinity stress influences the expression of stored seed transcripts and early offspring traits and test for genetic variation. We detected genotype-dependent parental environmental effects (transgenerational plasticity) on the expression levels of stored seed transcripts, seed size, and germination behavior of four M. truncatula genotypes. More than 50% of the transcripts detected in the mature, ungerminated seed transcriptome were annotated as regulating seed germination, some of which are involved in abiotic stress response and post-embryonic development. Some genotypes showed increased seed size in response to parental exposure to salinity stress, but no parental environmental influence on germination timing. In contrast, other genotypes showed no seed size differences across contrasting parental conditions but displayed transgenerational plasticity for germimation timing, with significantly delayed germination in saline conditions when parental plants were exposed to salinity. In genotypes that show significant transgenerational plastic germination response, we found significant coexpression networks derived from salt responsive transcripts involved in post-transcriptional regulation of the germination pathway. Consistent with the delayed germination response to saline conditions in these genotypes, we found genes associated with dormancy and up-regulation of abscisic acid (ABA). Our results demonstrate genetic variation in transgenerational plasticity within M. truncatula and show that parental exposure to salinity stress influences the expression of stored seed transcripts, seed weight, and germination behavior. Furthermore, we show that the parental environment influences gene expression to modulate biological pathways that are likely responsible for offspring germination responses to salinity stress.
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Wen, Xi; Yang, Sizhong; Horn, Fabian; Winkel, Matthias; Wagner, Dirk; Liebner, Susanne
2017-01-01
Methanogenic archaea are important for the global greenhouse gas budget since they produce methane under anoxic conditions in numerous natural environments such as oceans, estuaries, soils, and lakes. Whether and how environmental change will propagate into methanogenic assemblages of natural environments remains largely unknown owing to a poor understanding of global distribution patterns and environmental drivers of this specific group of microorganisms. In this study, we performed a meta-analysis targeting the biogeographic patterns and environmental controls of methanogenic communities using 94 public mcrA gene datasets. We show a global pattern of methanogenic archaea that is more associated with habitat filtering than with geographical dispersal. We identify salinity as the control on methanogenic community composition at global scale whereas pH and temperature are the major controls in non-saline soils and lakes. The importance of salinity for structuring methanogenic community composition is also reflected in the biogeography of methanogenic lineages and the physiological properties of methanogenic isolates. Linking methanogenic alpha-diversity with reported values of methane emission identifies estuaries as the most diverse methanogenic habitats with, however, minor contribution to the global methane budget. With salinity, temperature and pH our study identifies environmental drivers of methanogenic community composition facing drastic changes in many natural environments at the moment. However, consequences of this for the production of methane remain elusive owing to a lack of studies that combine methane production rate with community analysis. PMID:28769904
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Choi, Young Jae; Kim, Na Na; Shin, Hyun Suk; Choi, Cheol Young
2014-01-01
Leptin plays an important role in energy homeostasis and reproductive function in fish, especially in reproduction. Migrating fish, such as salmonoids, are affected by external environmental factors, and salinity changes are a particularly important influence on spawning migrations. The aim of this study was to test whether changes in salinity affect the expression of leptin, estrogen receptors (ERs), and vitellogenin (VTG) in chum salmon (Oncorhynchus keta). The expression and activity of leptin, the expression of ERs and VTG, and the levels of estradiol-17β and cortisol increased after the fish were transferred to FW, demonstrating that changes in salinity stimulate the HPG axis in migrating female chum salmon. These findings reveal details about the role of elevated leptin levels and sex steroid hormones in stimulating sexual maturation and reproduction in response to salinity changes in chum salmon. PMID:25049977
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Freshwater to seawater transitions in migratory fishes
Zydlewski, Joseph D.; Michael P. Wilkie,
2012-01-01
The transition from freshwater to seawater is integral to the life history of many fishes. Diverse migratory fishes express anadromous, catadromous, and amphidromous life histories, while others make incomplete transits between freshwater and seawater. The physiological mechanisms of osmoregulation are widely conserved among phylogenetically diverse species. Diadromous fishes moving between freshwater and seawater develop osmoregulatory mechanisms for different environmental salinities. Freshwater to seawater transition involves hormonally mediated changes in gill ionocytes and the transport proteins associated with hypoosmoregulation, increased seawater ingestion and water absorption in the intestine, and reduced urinary water losses. Fishes attain salinity tolerance through early development, gradual acclimation, or environmentally or developmentally cued adaptations. This chapter describes adaptations in diverse taxa and the effects of salinity on growth. Identifying common strategies in diadromous fishes moving between freshwater and seawater will reveal the ecological and physiological basis for maintaining homeostasis in different salinities, and inform efforts to conserve and manage migratory euryhaline fishes.
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Thermal adaptation and clinal mitochondrial DNA variation of European anchovy
Silva, Gonçalo; Lima, Fernando P.; Martel, Paulo; Castilho, Rita
2014-01-01
Natural populations of widely distributed organisms often exhibit genetic clinal variation over their geographical ranges. The European anchovy, Engraulis encrasicolus, illustrates this by displaying a two-clade mitochondrial structure clinally arranged along the eastern Atlantic. One clade has low frequencies at higher latitudes, whereas the other has an anti-tropical distribution, with frequencies decreasing towards the tropics. The distribution pattern of these clades has been explained as a consequence of secondary contact after an ancient geographical isolation. However, it is not unlikely that selection acts on mitochondria whose genes are involved in relevant oxidative phosphorylation processes. In this study, we performed selection tests on a fragment of 1044 bp of the mitochondrial cytochrome b gene using 455 individuals from 18 locations. We also tested correlations of six environmental features: temperature, salinity, apparent oxygen utilization and nutrient concentrations of phosphate, nitrate and silicate, on a compilation of mitochondrial clade frequencies from 66 sampling sites comprising 2776 specimens from previously published studies. Positive selection in a single codon was detected predominantly (99%) in the anti-tropical clade and temperature was the most relevant environmental predictor, contributing with 59% of the variance in the geographical distribution of clade frequencies. These findings strongly suggest that temperature is shaping the contemporary distribution of mitochondrial DNA clade frequencies in the European anchovy. PMID:25143035
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Persistence of Bacteroides ovatus under simulated sunlight irradiation
2014-01-01
Background Bacteroides ovatus, a member of the genus Bacteroides, is considered for use in molecular-based methods as a general fecal indicator. However, knowledge on its fate and persistence after a fecal contamination event remains limited. In this study, the persistence of B. ovatus was evaluated under simulated sunlight exposure and in conditions similar to freshwater and seawater. By combining propidium monoazide (PMA) treatment and quantitative polymerase chain reaction (qPCR) detection, the decay rates of B. ovatus were determined in the presence and absence of exogenous photosensitizers and in salinity up to 39.5 parts per thousand at 27°C. Results UVB was found to be important for B. ovatus decay, averaging a 4 log10 of decay over 6 h of exposure without the presence of extracellular photosensitizers. The addition of NaNO2, an exogenous sensitizer producing hydroxyl radicals, did not significantly change the decay rate of B. ovatus in both low and high salinity water, while the exogenous sensitizer algae organic matter (AOM) slowed down the decay of B. ovatus in low salinity water. At seawater salinity, the decay rate of B. ovatus was slower than that in low salinity water, except when both NaNO2 and AOM were present. Conclusion The results of laboratory experiments suggest that if B. ovatus is released into either freshwater or seawater environment in the evening, 50% of it may be intact by the next morning; if it is released at noon, only 50% may be intact after a mere 5 min of full spectrum irradiation on a clear day. This study provides a mechanistic understanding to some of the important environmental relevant factors that influenced the inactivation kinetics of B. ovatus in the presence of sunlight irradiation, and would facilitate the use of B. ovatus to indicate the occurrence of fecal contamination. PMID:24993443
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NASA Astrophysics Data System (ADS)
Banerjee, Kakoli; Ghosh, Rajrupa; Homechaudhuri, Sumit; Mitra, Abhijit
2009-10-01
The biochemical composition of red seaweeds, Catenella repens was investigated in this present study along with subsequent analysis of relevant physico-chemical variables. In this study, the relationship between the nutritive components of this species and the ambient environmental parameters was established. Protein content varied from 2.78 ± 0.30% of dry weight (stn.3) to 16.03 ± 0.96% of dry weight (stn.1) with highest values during monsoon. The protein levels were positively correlated with dissolved nitrate content and negatively correlated with water temperature (except stn.3) and salinity. Carbohydrate content of this species varied significantly ( p < 0.05) during pre-monsoon between stations and the values showed positive relationship with salinity and surface water temperature. In contrast to carbohydrate, lipid concentration was lowest in values and varied very slightly between seasons and stations. Astaxanthin content of the seaweed species was greater in pre-monsoon than monsoon and post-monsoon in all the selected stations. Compared with the three seasons, samples of red seaweed collected in pre-monsoon has high carbohydrate-astaxanthin in contrast to protein-lipid which showed high values during monsoon. Statistical analysis computed among the environmental and biochemical parameters suggests the potential role played by the abiotic parameters on biosynthetic pathways of seaweed. This paper also highlights the influence of the nutritional quality of water that can be used for mass cultivation of Catenella repens.
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The use of short rotation willows and poplars for the recycling of saline waste waters
Jaconette Mirck; Ronald S. Jr. Zalesny; Ioannis Dimitriou; Jill A. Zalesny; Timothy A. Volk; Warren E. Mabee
2009-01-01
The production of high-salinity waste waters by landfills and other waste sites causes environmental concerns. This waste water often contains high concentrations of sodium and chloride, which may end up in local ground and surface waters. Vegetation filter systems comprised of willows and poplars can be used for the recycling of saline waste water. These vegetation...
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Karan, Ratna; DeLeon, Teresa; Biradar, Hanamareddy; Subudhi, Prasanta K.
2012-01-01
Background Salinity is a major environmental factor limiting productivity of crop plants including rice in which wide range of natural variability exists. Although recent evidences implicate epigenetic mechanisms for modulating the gene expression in plants under environmental stresses, epigenetic changes and their functional consequences under salinity stress in rice are underexplored. DNA methylation is one of the epigenetic mechanisms regulating gene expression in plant’s responses to environmental stresses. Better understanding of epigenetic regulation of plant growth and response to environmental stresses may create novel heritable variation for crop improvement. Methodology/Principal Findings Methylation sensitive amplification polymorphism (MSAP) technique was used to assess the effect of salt stress on extent and patterns of DNA methylation in four genotypes of rice differing in the degree of salinity tolerance. Overall, the amount of DNA methylation was more in shoot compared to root and the contribution of fully methylated loci was always more than hemi-methylated loci. Sequencing of ten randomly selected MSAP fragments indicated gene-body specific DNA methylation of retrotransposons, stress responsive genes, and chromatin modification genes, distributed on different rice chromosomes. Bisulphite sequencing and quantitative RT-PCR analysis of selected MSAP loci showed that cytosine methylation changes under salinity as well as gene expression varied with genotypes and tissue types irrespective of the level of salinity tolerance of rice genotypes. Conclusions/Significance The gene body methylation may have an important role in regulating gene expression in organ and genotype specific manner under salinity stress. Association between salt tolerance and methylation changes observed in some cases suggested that many methylation changes are not “directed”. The natural genetic variation for salt tolerance observed in rice germplasm may be independent of the extent and pattern of DNA methylation which may have been induced by abiotic stress followed by accumulation through the natural selection process. PMID:22761959
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Evaluating physiological responses of plants to salinity stress
Negrão, S.; Schmöckel, S. M.; Tester, M.
2017-01-01
Background Because soil salinity is a major abiotic constraint affecting crop yield, much research has been conducted to develop plants with improved salinity tolerance. Salinity stress impacts many aspects of a plant’s physiology, making it difficult to study in toto. Instead, it is more tractable to dissect the plant’s response into traits that are hypothesized to be involved in the overall tolerance of the plant to salinity. Scope and conclusions We discuss how to quantify the impact of salinity on different traits, such as relative growth rate, water relations, transpiration, transpiration use efficiency, ionic relations, photosynthesis, senescence, yield and yield components. We also suggest some guidelines to assist with the selection of appropriate experimental systems, imposition of salinity stress, and obtaining and analysing relevant physiological data using appropriate indices. We illustrate how these indices can be used to identify relationships amongst the proposed traits to identify which traits are the most important contributors to salinity tolerance. Salinity tolerance is complex and involves many genes, but progress has been made in studying the mechanisms underlying a plant’s response to salinity. Nevertheless, several previous studies on salinity tolerance could have benefited from improved experimental design. We hope that this paper will provide pertinent information to researchers on performing proficient assays and interpreting results from salinity tolerance experiments. PMID:27707746
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Effect on Soil Properties of BcWRKY1 Transgenic Maize with Enhanced Salinity Tolerance
Zeng, Xing; Zhou, Yu; Zhu, Zhongjia; Zu, Hongyue
2016-01-01
Maize (Zea mays L.) is the most important cereal crop in the world. However, soil salinity has become a major problem affecting plant productivity due to arable field degradation. Thus, transgenic maize transformed with a salinity tolerance gene has been developed to further evaluate its salt tolerance and effects on agronomic traits. It is necessary to analyze the potential environmental risk of transgenic maize before further commercialization. Enzyme activities, physicochemical properties, and microbial populations were evaluated in saline and nonsaline rhizosphere soils from a transgenic maize line (WL-73) overexpressing BcWRKY1 and from wild-type (WT) maize LH1037. Measurements were taken at four growth stages (V3, V9, R1, and R6) and repeated in three consecutive years (2012–2014). There was no change in the rhizosphere soils of either WL-73 or WT plants in the four soil enzyme activities, seven soil physicochemical properties, and the populations of three soil organisms. The results of this study suggested that salinity tolerant transgenic maize had no adverse impact on soil properties in soil rhizosphere during three consecutive years at two different locations and provided a theoretical basis for environmental impact monitoring of salinity tolerant transgenic maize. PMID:27990421
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Green, A Laine; Gu, Pengfei; De Felice, Milena; Dodick, David; Ossipov, Michael H; Porreca, Frank
2014-01-01
Objective The objective of this article is to evaluate electrically evoked thresholds for cortical spreading depression (CSD) and stress-induced activation of trigeminal afferents in a rat model of medication-overuse headache (MOH). Methods Sumatriptan or saline was delivered subcutaneously by osmotic minipump for six days to Sprague-Dawley rats. Two weeks after pump removal, animals were anesthetized and recording/stimulating electrodes implanted. The animals were pretreated with vehicle or topiramate followed by graded electrical stimulation within the visual cortex. CSD events were identified by decreased EEG amplitude and DC potential shift. Additional unanesthetized sumatriptan or saline-pretreated rats were exposed to bright light environmental stress and periorbital and hindpaw withdrawal thresholds were measured. Following CSD stimulation or environmental stress, immunohistochemical staining for Fos in the trigeminal nucleus caudalis (TNC) was performed. Results Sumatriptan pre-exposure significantly decreased electrical stimulation threshold to generate a CSD event. Topiramate normalized the decreased CSD threshold as well as stress-induced behavioral withdrawal thresholds in sumatriptan-treated rats compared to saline-treated animals. Moreover, CSD and environmental stress increased Fos expression in the TNC of sumatriptan-treated rats, and these effects were blocked by topiramate. Environmental stress did not elicit cutaneous allodynia or elevate TNC Fos expression in saline-treated rats. Conclusions A previous period of sumatriptan exposure produced long-lasting increased susceptibility to evoked CSD and environmental stress-induced activation of the TNC that was prevented by topiramate. Lowered CSD threshold, and enhanced consequences of CSD events (increased activation of TNC), may represent an underlying biological mechanism of MOH related to triptans. PMID:24335852
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Kültz, Dietmar; Li, Johnathon; Gardell, Alison; Sacchi, Romina
2013-01-01
A two-tiered label-free quantitative (LFQ) proteomics workflow was used to elucidate how salinity affects the molecular phenotype, i.e. proteome, of gills from a cichlid fish, the euryhaline tilapia (Oreochromis mossambicus). The workflow consists of initial global profiling of relative tryptic peptide abundances in treated versus control samples followed by targeted identification (by MS/MS) and quantitation (by chromatographic peak area integration) of validated peptides for each protein of interest. Fresh water acclimated tilapia were independently exposed in separate experiments to acute short-term (34 ppt) and gradual long-term (70 ppt, 90 ppt) salinity stress followed by molecular phenotyping of the gill proteome. The severity of salinity stress can be deduced with high technical reproducibility from the initial global label-free quantitative profiling step alone at both peptide and protein levels. However, an accurate regulation ratio can only be determined by targeted label-free quantitative profiling because not all peptides used for protein identification are also valid for quantitation. Of the three salinity challenges, gradual acclimation to 90 ppt has the most pronounced effect on gill molecular phenotype. Known salinity effects on tilapia gills, including an increase in the size and number of mitochondria-rich ionocytes, activities of specific ion transporters, and induction of specific molecular chaperones are reflected in the regulation of abundances of the corresponding proteins. Moreover, specific protein isoforms that are responsive to environmental salinity change are resolved and it is revealed that salinity effects on the mitochondrial proteome are nonuniform. Furthermore, protein NDRG1 has been identified as a novel key component of molecular phenotype restructuring during salinity-induced gill remodeling. In conclusion, besides confirming known effects of salinity on gills of euryhaline fish, molecular phenotyping reveals novel insight into proteome changes that underlie the remodeling of tilapia gill epithelium in response to environmental salinity change. PMID:24065692
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NASA Astrophysics Data System (ADS)
Xu, Z.; Hu, B.
2017-12-01
The interest to predict seawater intrusion and salinity distribution in Woodville Karst Plain (WKP) has increased due to the huge challenge on quality of drinkable water and serious environmental problems. Seawater intrudes into the conduit system from submarine karst caves at Spring Creek Spring due to density difference and sea level rising, nowadays the low salinity has been detected at Wakulla Spring which is 18 km from coastal line. The groundwater discharge at two major springs and salinity distribution in this area is controlled by the seawater/freshwater interaction under different rainfall conditions: during low rainfall periods, seawater flow into the submarine spring through karst windows, then the salinity rising at the submarine spring leads to seawater further intrudes into conduit system; during high rainfall periods, seawater is pushed out by fresh water discharge at submarine spring. The previous numerical studies of WKP mainly focused on the density independent transport modeling and seawater/freshwater discharge at major karst springs, in this study, a SEAWAT model has been developed to fully investigate the salinity distribution in the WKP under repeating phases of low rainfall and high rainfall periods, the conduit system was simulated as porous media with high conductivity and porosity. The precipitation, salinity and discharge at springs were used to calibrate the model. The results showed that the salinity distribution in porous media and conduit system is controlled by the rainfall change, in general, the salinity distribution inland under low rainfall conditions is much higher and wider than the high rainfall conditions. The results propose a prediction on the environmental problem caused by seawater intrusion in karst coastal aquifer, in addition, provide a visual and scientific basis for future groundwater remediation.
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Salinity Drives the Virioplankton Abundance but Not Production in Tropical Coastal Lagoons.
Junger, Pedro C; Amado, André M; Paranhos, Rodolfo; Cabral, Anderson S; Jacques, Saulo M S; Farjalla, Vinicius F
2018-01-01
Viruses are the most abundant components of microbial food webs and play important ecological and biogeochemical roles in aquatic ecosystems. Virioplankton is regulated by several environmental factors, such as salinity, turbidity, and humic substances. However, most of the studies aimed to investigate virioplankton regulation were conducted in temperate systems combining a limited range of environmental variables. In this study, virus abundance and production were determined and their relation to bacterial and limnological variables was assessed in 20 neighboring shallow tropical coastal lagoons that present wide environmental gradients of turbidity (2.32-571 NTU), water color (1.82-92.49 m -1 ), dissolved organic carbon (0.71-16.7 mM), salinity (0.13-332.1‰), and chlorophyll-a (0.28 to 134.5 μg L -1 ). Virus abundance varied from 0.37 × 10 8 to 117 × 10 8 virus-like-particle (VLP) mL -1 , with the highest values observed in highly salty aquatic systems. Salinity and heterotrophic bacterial abundance were the main variables positively driving viral abundances in these lagoons. We suggest that, with increased salinity, there is a decrease in the protozoan control on bacterial populations and lower bacterial diversity (higher encounter rates with virus specific hosts), both factors positively affecting virus abundance. Virus production varied from 0.68 × 10 7 to 56.5 × 10 7 VLP mL -1 h -1 and was regulated by bacterial production and total phosphorus, but it was not directly affected by salinity. The uncoupling between virus abundance and virus production supports that the hypothesis that the lack of grazing pressure on viral and bacterial populations is an important mechanism causing virus abundance to escalate with increasing salt concentrations.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Schmeide, Katja; Fritsch, Katharina; Lippold, Holger
2016-02-29
The objective of this project was to study the influence of increased salinities on interaction processes in the system radionuclide – organics – clay – aquifer. For this, complexation, redox, sorption, and diffusion studies were performed under variation of the ionic strength (up to 4 mol kg -1) and the background electrolyte (NaCl, CaCl 2, MgCl 2).
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Kase, Robert; Hansen, Peter D; Fischer, Birgit; Manz, Werner; Heininger, Peter; Reifferscheid, Georg
2009-01-01
The enzyme-linked receptor assay (ELRA) detects estrogenic and anti-estrogenic effects at the molecular level of receptor binding and is a useful tool for the integrative assessment of ecotoxicological potentials caused by hormonally active agents (HAA) and endocrine disrupting compounds (EDC). The main advantage of the ELRA is its high sample throughput and its robustness against cytotoxicity and microbial contamination. After a methodological adaptation to salinity of the ELRA, according to the first part of this study, which increased its salinity tolerance and sensitivity for 17-beta-estradiol, the optimised ELRA was used to investigate 13 native sediments characterised by different levels of salinity and chemical contamination. The applicability of the ELRA for routine analysis in environmental assessment was evaluated. Salinity is often a critical factor for bioassays in ecotoxicological sediment assessment. Therefore, salinity of the samples was additionally adjusted to different levels to characterise its influence on elution and binding processes of receptor-binding substances. The ELRA was carried out with the human estrogen receptor alpha (ER) in a 96-well microplate format using the experimental setup known from the competitive immunoassay based on ligand-protein interaction. It is an important improvement that a physiologically relevant receptor was used as a linking protein instead of an antibody. The microplates were coated with a 17-beta-estradiol-BSA conjugate, and dilution series of estradiol and of native sediment samples were added and incubated with the ER. After a washing step, a biotinylated mouse anti-ER antibody was added to each well. Receptor binding to estradiol, agonistic and antagonistic receptor binding, were determined by a streptavidin-POD-biotin complex with subsequent measurement of the peroxidase activity at the wavelength of 450 nm using a commercial ELISA multiplate reader. The sediment elutriates and pore water samples of sediments were tested in a dilution series to evaluate at which dilution step the receptor-binding potential ends. In the elution process (see Section 2.1 to 2.2), a method was developed to adjust the salinity to the levels of the reference testings, which offers an appropriate option to adjust the salinity in both directions. Statistical evaluation was made with a combination of the Mann-Whitney U test and the pT-method. This part of the study characterised the environmental factor 'salinity' for prospective applications of the ELRA. Using reference substances such as 17-beta-estradiol, the ELRA showed sigmoid concentration-effect relations over a broad range from 0.05 mug/l to 100 mug/l under physiological conditions. After methodological optimisation, both sensitivity and tolerance of the assay against salinity could be significantly raised, and the ELRA became applicable under salinity conditions up to concentrations of 20.5 per thousand. The mean relative inter-test error (n = 3) was around 11% with reference substances and below 5% for single sediments elutriates in three replicates each. For sediment testings, the pore water and different salinity-adjusted elutriates of 13 sediments were used. A clear differentiation of the receptor-binding potential could be reached by application of the pT-method. Thereby, pT-values from one to six could be assigned to the sediments, and the deviation caused by the different salinity conditions was one pT-value. The mean standard deviation in the salinity adaptation procedure of the elutriates was below 5%. Although the ELRA has already been used for assessments of wastewater, sludge and soil, its applicability for samples to different salinity levels has not been investigated so far. Even if the ELRA is not as sensitive as the E-screen or the YES-assay, with regard to reference substances like 17-beta-estradiol, it is a very useful tool for pre-screening, because it is able to integrate both estrogenic as well as anti-estrogenic receptor-binding effects. According to the results of sediment testing, and given the integrative power to detect different directions of effects, the ELRA shows sufficient sensitivity and salinity tolerance to discriminate receptor-binding potentials in environmental samples. The optimised ELRA assay is a fast, cost-effective, reliable and highly reproducible tool that can be used for high-throughput screening in a microplate format in detecting both estrogenic and anti-estrogenic effects. Additionally, the ELRA is robust against microbial contaminations, and is not susceptible towards cytotoxic interferences like the common cell-culture methods. The general applicability and sufficient sensitivity of the ELRA was shown in freshwater environments. Marine and brackish samples can be measured up to salinity levels of 20.5 per thousand. In view of the proven sensitivity, functionality and the fastness of the ELRA, it is recommendable to standardise the test method. At the moment, no adequate in vitro test procedure exists which is standardised to DIN or ISO levels. The E-screen and the yeast estrogen/androgen screens (YES/YAS) sometimes underlie strong cytotoxic effects, as reported in the first part of this study. Further development of an ELRA assay using human androgen receptors appears to be very promising to gain information about androgenic and anti-androgenic effects, too. This would offer a possibility to use the ELRA as a fast and reliable pre-screening tool for the detection of endocrine potentials, thus minimising time and cost-expensive animal experiments.
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1989-06-01
completely, oceanic salinities (34 ppt) to mesohaline (5-18 and metabolic rate partly, to a sinusoidal ppt) estuarine conditions (Bayne et al. 1976a... salinity change is large Newfoundland acclimated neither their feeding enough (reviewed by Davenport 1982). It can rate nor their metabolic rate to...mediating their conditions, and energ, requirements are response to a salinity change. Although larvae supplied by anaerobic metabolic pathways from the
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Amphibious Ready Group/Marine Expeditionary Unit Readiness Training Final Environmental Assessment
2003-04-11
above and below by the Pensacola Clay confining bed. This clay layer restricts the downward migration of pollutants and restricts saline water from...separates the Upper and Lower Limestone units. Because it is saline , the Lower Limestone unit is not used as a water source (U.S. Air Force, 1995...and a freshwater species, Ruppia maritima (widgeon grass). Widgeon grass is most common in brackish waters but can tolerate higher salinities
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Brewster-Wingard, G. L.; Ishman, S.E.
1999-01-01
Understanding the natural spatial and temporal variability that exists within an ecosystem is a critical component of efforts to restore systems to their natural state. Analysis of benthic foraminifers and molluscs from modern monitoring sites within Florida Bay allows us to determine what environmental parameters control spatial and temporal variability of their assemblages. Faunal assemblages associated with specific environmental parameters, including salinity and substrate, serve as proxies for an interpretation of paleoecologic data. The faunal record preserved in two shallow (< 2 m) cores in central Florida Bay (Russell Bank and Bob Allen Bank) provides a record of historical trends in environmental parameters for those sites. Analysis of these two cores has revealed two distinct patterns of salinity change at these sites: 1) a long-term trend of slightly increasing average salinity; and 2) a relatively rapid change to salinity fluctuations of greater frequency and amplitude, beginning around the turn of the century and becoming most pronounced after 1940. The degree of variability in substrate types at each locality limits interpretations of substrate trends to specific sites. A common sequence of change is present in the Russell Bank and Bob Allen Bank cores: from mixed grass and bare-sediment indicators at the bottom of the cores, to bare-sediment dwellers in the center, to a dominance of vegetative-cover indicators at the top of the cores. Changes in interpreted salinity patterns around the turn of the century are consistent with the timing of the construction of the Flagler Railroad from 1905 to 1912, and the Tamiami Trail and the canal and levee systems between 1915 and 1928. Beginning around 1940, the changes in the frequency and amplitude of salinity fluctuations may be related to changes in water management practices, meteorologic events (frequent hurricanes coupled with severe droughts in 1943 and 1944), or a combination of factors. The correspondence of these changes in Florida Bay with changes in the terrestrial Everglades suggests factors affecting the entire ecosystem are responsible for the salinity and substrate patterns seen in Florida Bay.
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NASA Astrophysics Data System (ADS)
Lee, Yichao; Chang, Shuiping
2017-05-01
Spirogyra is a genus of widely distributed, large green fresh water algae. This study discovered that changes in salinity can induce Spirogyra fluviatilis to produce amounts of extracellular polymeric substance (EPS) when controlling other environmental conditions. If culturing S. fluviatilis with salinity greater than a 3.0‰ medium for 4 hours, the secretion EPS will be changed. And the level of polysaccharides and proteins, the primary components of EPS, is slightly increased in accordance with the increase in the salinity. But the proteins to polysaccharides ratio changes are not significantly
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Numerical Simulation of Salinity and Dissolved Oxygen at Perdido Bay and Adjacent Coastal Ocean
Environmental Fluid Dynamic Code (EFDC), a numerical estuarine and coastal ocean circulation hydrodynamic model, was used to simulate the distribution of the salinity, temperature, nutrients and dissolved oxygen (DO) in Perdido Bay and adjacent Gulf of Mexico. External forcing fa...
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DISPERSANT EFFECTIVENESS ON OIL SPILLS - IMPACT OF ENVIRONMENTAL FACTORS
When a dispersant is applied to an oil slick, its effectiveness in dispersing the spilled oil depends on various factors such as oil properties, wave mixing energy, temperature of both oil and water, and salinity of the water. Estuaries represent water with varying salinities. In...
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Dunn, Paul H; Young, Craig M
2015-04-01
Estuaries can be harsh habitats for the marine animals that enter them, but they may also provide these species with sub-saline refuges from their parasites. The nemertean egg predator Carcinonemertes errans is known to occur less frequently and in smaller numbers on its host, the Dungeness crab Metacarcinus magister, when the hosts are found within estuaries. We examined the temperature and salinity tolerances of C. errans to determine if this observed distribution represents a true salinity refuge. We monitored the survival of juvenile and larval worms exposed to ecologically relevant salinities (5-30) and temperatures (8-20 °C) over the course of several days under laboratory conditions. Juvenile worms were unaffected by the experimental temperature levels and exhibited robustness to salinity treatments 25 and 30. However, significant mortality was seen at salinity treatments 20 and below. Larvae were less tolerant than juveniles to lowered salinity and were also somewhat more susceptible to the higher temperatures tested. Given that the Dungeness crab can tolerate forays into mesohaline (salinity 5-18) waters for several days at a time, our findings suggest that salinity gradients play an important role in creating a parasite refuge for this species within the estuaries of the Pacific Northwest. © 2015 Marine Biological Laboratory.
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Dickinson, Gary H; Matoo, Omera B; Tourek, Robert T; Sokolova, Inna M; Beniash, Elia
2013-07-15
Ocean acidification due to increasing atmospheric CO2 concentrations results in a decrease in seawater pH and shifts in the carbonate chemistry that can negatively affect marine organisms. Marine bivalves such as the hard-shell clam, Mercenaria mercenaria, serve as ecosystem engineers in estuaries and coastal zones of the western Atlantic and, as for many marine calcifiers, are sensitive to the impacts of ocean acidification. In estuaries, the effects of ocean acidification can be exacerbated by low buffering capacity of brackish waters, acidic inputs from freshwaters and land, and/or the negative effects of salinity on the physiology of organisms. We determined the interactive effects of 21 weeks of exposure to different levels of CO2 (~395, 800 and 1500 μatm corresponding to pH of 8.2, 8.1 and 7.7, respectively) and salinity (32 versus 16) on biomineralization, shell properties and energy metabolism of juvenile hard-shell clams. Low salinity had profound effects on survival, energy metabolism and biomineralization of hard-shell clams and modulated their responses to elevated PCO2. Negative effects of low salinity in juvenile clams were mostly due to the strongly elevated basal energy demand, indicating energy deficiency, that led to reduced growth, elevated mortality and impaired shell maintenance (evidenced by the extensive damage to the periostracum). The effects of elevated PCO2 on physiology and biomineralization of hard-shell clams were more complex. Elevated PCO2 (~800-1500 μatm) had no significant effects on standard metabolic rates (indicative of the basal energy demand), but affected growth and shell mechanical properties in juvenile clams. Moderate hypercapnia (~800 μatm PCO2) increased shell and tissue growth and reduced mortality of juvenile clams in high salinity exposures; however, these effects were abolished under the low salinity conditions or at high PCO2 (~1500 μatm). Mechanical properties of the shell (measured as microhardness and fracture toughness of the shells) were negatively affected by elevated CO2 alone or in combination with low salinity, which may have important implications for protection against predators or environmental stressors. Our data indicate that environmental salinity can strongly modulate responses to ocean acidification in hard-shell clams and thus should be taken into account when predicting the effects of ocean acidification on estuarine bivalves.
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Kwok, K W H; Leung, K M Y
2005-01-01
Intertidal harpacticoid copepods are commonly used in eco-toxicity tests worldwide. They predominately live in mid-high shore rock pools and often experience a wide range of temperature and salinity fluctuation. Most eco-toxicity tests are conducted at fixed temperature and salinity and thus the influence of these environmental factors on chemical toxicity is largely unknown. This study investigated the combined effect of temperature and salinity on the acute toxicity of the copepod Tigriopus japonicus against two common biocides, copper (Cu) and tributyltin (TBT) using a 2 x 3 x 4 factorial design (i.e. two temperatures: 25 and 35 degrees C; three salinities: 15.0 per thousand, 34.5 per thousand and 45.0 per thousand; three levels of the biocide plus a control). Copper sulphate and tributyltin chloride were used as the test chemicals while distilled water and acetone were utilised as solvents for Cu and TBT respectively. 96 h-LC50s of Cu and TBT were 1024 and 0.149 microg l(-1) respectively (at 25 degrees C; 34.5 per thousand) and, based on these results, nominal biocide concentrations of LC0 (i.e. control), LC30, LC50 and LC70 were employed. Analysis of Covariance using 'concentration' as the covariate and both 'temperature' and 'salinity' as fixed factors, showed a significant interaction between temperature and salinity effects for Cu, mortality increasing with temperature but decreasing with elevated salinity. A similar result was revealed for TBT. Both temperature and salinity are, therefore, important factors affecting the results of acute eco-toxicity tests using these marine copepods. We recommend that such eco-toxicity tests should be conducted at a range of environmentally realistic temperature/salinity regimes, as this will enhance the sensitivity of the test and improve the safety margin in line with the precautionary principle.
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Yu, Fei; Addison, Owen; Baker, Stephen J; Davenport, Alison J
2015-01-01
Titanium and its alloys are routinely used as biomedical implants and are usually considered to be corrosion resistant under physiological conditions. However, during inflammation, chemical modifications of the peri-implant environment including acidification occur. In addition certain biomolecules including lipopolysaccharide (LPS), a component of Gram-negative bacterial cell walls and driver of inflammation have been shown to interact strongly with Ti and modify its corrosion resistance. Gram-negative microbes are abundant in biofilms which form on dental implants. The objective was to investigate the influence of LPS on the corrosion properties of relevant biomedical Ti substrates as a function of environmental acidity. Inductively coupled plasma mass spectrometry was used to quantify Ti dissolution following immersion testing in physiological saline for three common biomedical grades of Ti (ASTM Grade 2, Grade 4 and Grade 5). Complementary electrochemical tests including anodic and cathodic polarisation experiments and potentiostatic measurements were also conducted. All three Ti alloys were observed to behave similarly and ion release was sensitive to pH of the immersion solution. However, LPS significantly inhibited Ti release under the most acidic conditions (pH 2), which may develop in localized corrosion sites, but promoted dissolution at pH 4–7, which would be more commonly encountered physiologically. The observed pattern of sensitivity to environmental acidity of the effect of LPS on Ti corrosion has not previously been reported. LPS is found extensively on the surfaces of skin and mucosal penetrating Ti implants and the findings are therefore relevant when considering the chemical stability of Ti implant surfaces in vivo. PMID:25634122
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Proceedings of the Conference on Environmental Toxicology (9th), 28, 29, and 30 March 1979
1979-08-01
collected on all persons by the method of saline induction. All samples were analyzed in the laboratory of Dr. Geno Saccomanno, Grand Junction, Colorado...hydrazine was labeled by 1 4 C-methyl-methionine to a greater extent than in saline -treated animals. In the current studies, young adult fasted male...METHIONINE: COMPARISON TO METHYLATION IN HYDRAZINE- AND MMH-TREATED RATS 7-Methylguanine Content Treatment (pMole/Mole Guanine) Saline 0 (None
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Jiang, J.; DeAngelis, D.L.; Smith, T. J.; Teh, S.Y.; Koh, H. L.
2012-01-01
Coastal vegetation of South Florida typically comprises salinity-tolerant mangroves bordering salinity-intolerant hardwood hammocks and fresh water marshes. Two primary ecological factors appear to influence the maintenance of mangrove/hammock ecotones against changes that might occur due to disturbances. One of these is a gradient in one or more environmental factors. The other is the action of positive feedback mechanisms, in which each vegetation community influences its local environment to favor itself, reinforcing the boundary between communities. The relative contributions of these two factors, however, can be hard to discern. A spatially explicit individual-based model of vegetation, coupled with a model of soil hydrology and salinity dynamics is presented here to simulate mangrove/hammock ecotones in the coastal margin habitats of South Florida. The model simulation results indicate that an environmental gradient of salinity, caused by tidal flux, is the key factor separating vegetation communities, while positive feedback involving the different interaction of each vegetation type with the vadose zone salinity increases the sharpness of boundaries, and maintains the ecological resilience of mangrove/hammock ecotones against small disturbances. Investigation of effects of precipitation on positive feedback indicates that the dry season, with its low precipitation, is the period of strongest positive feedback. ?? 2011 Springer Science+Business Media B.V. (outside the USA).
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Abstract
For biomarkers to be useful in assessing anthropogenic impacts in field studies involving aquatic organisms, they should not be affected by naturally occurring changes in environmental parameters such as salinity. This is especially important in estuarine envi...
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Larvae of the rock crab Cancer irroratus were cultured under specific environmental regimes to examine the influence of temperature and salinity on respiration and excretion rates during development. In addition, the type of biochemical substrate used for energy production was de...
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Kincheloe, Karen L.; Stehn, Robert A.
1991-01-01
Tundra vegetation and environmental variables were sampled on the Yukon–Kuskokwim delta in western Alaska. On transects extending from intertidal mudflat to upland tundra, we estimated cover by vascular plant species, soil moisture, salinity, relative elevation, depth to permafrost, and distance upriver from the coast. Two-way indicator species analysis (TWINSPAN) classified 21 communities. Ordination by detrended correspondence analysis (DECORANA) revealed a gradient correlated with the combination of elevation, permafrost depth, and salinity along the first axis for both upriver and downriver transects.
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Brewster-Wingard, G. L.; Ishman, S.E.; Willard, D.A.; Edwards, L.E.; Holmes, C.W.
1997-01-01
The fauna and flora preserved in two cores, 19A and 19B, from the south side of Russell Bank (N 25 03.831', W 80 37.486') in north-central Florida Bay, Everglades National Park, Florida, record a history of environmental change over the last century. The benthic foraminifera and molluscs indicate fluctuating salinities with increasing average salinity upcore in core 19B. Shifts from low salinity (12-15 ppt) to higher average salinity (30 ppt) occurred at 70-66 cm and 24-18 cm in core 19B (approximately 1937-1940 and 1975-1980). The inverse, shifts from periods of higher average salinity to periods of lower salinity, occurred at 140 cm, 90 cm, and 42 cm (approximately 1880, 1921, and 1960). Significant changes in the molluscan fauna indicative of specific substrate types occur at 88 cm, 68 cm, and 22 cm. The lower portion of the core is dominated by a mixture of sediment and grass dwellers, the middle portion by sediment dwellers, and the upper portion of the core by grass and finally grass and algae dwellers. Changes occur in the floral assemblages in core 19A, but the significance of these changes is unclear. Three subtle shifts occur in the pollen assemblages indicating the onshore vegetation was responding to some environmental factor. Two peaks in dinocyst abundance occur in core 19A, but the composition of dinocyst assemblages remains relatively stable throughout the core. Correspondence between changes in salinity and onshore vegetation changes is consistent with results from previous cores. The pattern of increased salinity upcore is consistent with patterns seen in core T24 from the mouth of Taylor Creek and in core 6A from Bob Allen mudbank.
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Liu, Kaihui; Ding, Xiaowei; Tang, Xiaofei; Wang, Jianjun; Li, Wenjun; Yan, Qingyun; Liu, Zhenghua
2018-01-01
Understanding the effects of environmental factors on microbial communities is critical for microbial ecology, but it remains challenging. In this study, we examined the diversity (alpha diversity) and community compositions (beta diversity) of prokaryotes and fungi in hypersaline sediments and salinized soils from northern China. Environmental variables were highly correlated, but they differed significantly between the sediments and saline soils. The compositions of prokaryotic and fungal communities in the hypersaline sediments were different from those in adjacent saline-alkaline soils, indicating a habitat-specific microbial distribution pattern. The macroelements (S, P, K, Mg, and Fe) and Ca were, respectively, correlated closely with the alpha diversity of prokaryotes and fungi, while the macronutrients (e.g., Na, S, P, and Ca) were correlated with the prokaryotic and fungal beta-diversity ( P ≤ 0.05). And, the nine microelements (e.g., Al, Ba, Co, Hg, and Mn) and micronutrients (Ba, Cd, and Sr) individually shaped the alpha diversity of prokaryotes and fungi, while the six microelements (e.g., As, Ba, Cr, and Ge) and only the trace elements (Cr and Cu), respectively, influenced the beta diversity of prokaryotes and fungi ( P < 0.05). Variation-partitioning analysis (VPA) showed that environmental variables jointly explained 55.49% and 32.27% of the total variation for the prokaryotic and fungal communities, respectively. Together, our findings demonstrate that the diversity and community composition of the prokaryotes and fungi were driven by different macro and microelements in saline habitats, and that geochemical elements could more widely regulate the diversity and community composition of prokaryotes than these of fungi.
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Environmental Influences on the Fish Assemblage of the Humber Estuary, U.K.
NASA Astrophysics Data System (ADS)
Marshall, S.; Elliott, M.
1998-02-01
Salinity, temperature, turbidity and dissolved oxygen were measured in conjunction with a series of fish samples taken by a 2 m beam trawl from 14 sites throughout the Humber estuary, U.K., over the period April 1992 to November 1994. Sediment type was not measured as the literature indicates that the area is homogeneous. The influences of environmental factors and the characteristics of the fish assemblage were analysed using a range of multivariate techniques, including two-way indicator species analysis, canonical correspondence analysis, principal components analysis and Spearman rank correlation. The analyses indicate that salinity is the dominant factor influencing the distribution of the species, with temperature also having a major influence. Of the species examined, whiting (Merlangius merlangus), sole (Solea solea), flounder (Pleuronectes flesus), sprat (Sprattus sprattus) and herring (Clupea harengus) showed a correlation in distribution to temperature, sole, plaice (Pleuronectes platessa), pogge (Agonus cataphractus) and stickleback (Gasterosteus aculeatus) to salinity, and whiting, flounder, pogge and stickleback to dissolved oxygen. Only cod (Gadus morhua) showed a correlation with tidal state, while whiting, pogge and stickleback were correlated to depth. Unlike in some other estuaries, turbidity did not influence the composition of the fish assemblage. Temperature and salinity fluctuations appear to influence different aspects of the community, with temperature proving to be the best predictor of total abundance, while salinity influenced the species richness and total biomass. The analyses demonstrate the most important variables with regard to environmental-biotic interactions, although they also indicate that the variables measured do not account for all of the observed variation in fish biomass and abundance.
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Saline Systems highlights for 2005
2006-01-01
On the 4th of July, 2005, the Saline Systems editorial group launched the new online open access journal, Saline Systems, with BioMed Central as the publisher. The scope of the journal includes both basic and applied research on halophilic organisms and saline environments, from gene systems to ecosystems. The stated goal of the journal is to meet publication needs for researchers working in coastal and inland saline environments and provide an interdisciplinary and readily accessible forum for scientists worldwide. The inaugural volume of the journal contains a significant number of high quality original research papers and reviews on a wide range of relevant topics. At the end of the launch period, from January 1, 2006 onwards, the journal will be introducing article-processing charges to cover the cost of publication. Charges will be partly or completely waived for authors from BioMed Central institutional subscribers and in cases of financial hardship. PMID:16417635
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NASA Astrophysics Data System (ADS)
Bozzeda, Fabio; Zangrilli, Maria Paola; Defeo, Omar
2016-06-01
A Fuzzy Naïve Bayes (FNB) classifier was developed to assess large-scale variations in abundance, species richness and diversity of the macrofauna inhabiting fifteen Uruguayan sandy beaches affected by the effects of beach morphodynamics and the estuarine gradient generated by Rio de la Plata. Information from six beaches was used to estimate FNB parameters, while abiotic data of the remaining nine beaches were used to forecast abundance, species richness and diversity. FNB simulations reproduced the general increasing trend of target variables from inner estuarine reflective beaches to marine dissipative ones. The FNB model also identified a threshold value of salinity range beyond which diversity markedly increased towards marine beaches. Salinity range is suggested as an ecological master factor governing distributional patterns in sandy beach macrofauna. However, the model: 1) underestimated abundance and species richness at the innermost estuarine beach, with the lowest salinity, and 2) overestimated species richness in marine beaches with a reflective morphodynamic state, which is strongly linked to low abundance, species richness and diversity. Therefore, future modeling efforts should be refined by giving a dissimilar weigh to the gradients defined by estuarine (estuarine beaches) and morphodynamic (marine beaches) variables, which could improve predictions of target variables. Our modeling approach could be applied to a wide spectrum of issues, ranging from basic ecology to social-ecological systems. This approach seems relevant, given the current challenge to develop predictive methodologies to assess the simultaneous and nonlinear effects of anthropogenic and natural impacts in coastal ecosystems.
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1985-06-01
correlated so quickly that prior salinity with temperature, and was influenced acclimation has no effect on laboratory more by cold water than by warm (Fahy...24A. (Woods Hole) 128:143-168. Bush, C..P., and J.S. Weis. 1983. Baker-Dittus, A.M. 1978. Foraging Effects of salinity on fertilization patterns of...population size structure of Sharp, and J.M. Neff. 1979. The the common mummichog (Fundulus combined effect of salinity , heteroclitus). Estuarine Coastal
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1984-04-01
species composition, hydroperiod, soils, and degree of salinity . Wetland communities and their dominant vegetation in Florida, as defined by the...Environmental Effects Laboratory of WES (1978), include: 9 a. Saltwater aquatic--Permanently flooded by saline or brack- ish water. Dominated by attached...Thalassis testudinum) is a typical species. b. Saltwater coastal flat--25 percent or less vegetative cover. Occasionally or regularly flooded by saline water
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Influence of temperature, oxygen and salinity on the metabolism of the European sea bass
NASA Astrophysics Data System (ADS)
Claireaux, G.; Lagardère, J.-P.
1999-09-01
Standard (SMR) and routine (RMR) metabolic rates of groups (4 to 5 individuals) of European sea bass ( Dicentrarchus labrax) were measured at combinations of the following factors: temperature (10, 15, 20 and 25°C), oxygenation level (air saturation to 1.5 mg dm -3) and salinity (30, 20, 10 and 5‰). The influence of these environmental conditions on fish metabolic demand was then analysed through ANOVA. At 10, 15, 20 and 25°C, standard metabolic rates were 36, 65, 89, and 91 mg O 2 kg -1 h -1, respectively, while routine oxygen consumptions covered most of the metabolic range accessible. Osmoregulatory costs are linked to metabolic activity through ventilation. This relationship was highlighted by the observed interaction between environmental salinity and temperature. We were, however, unable to detect interactions between salinity and routine metabolic rate, or between salinity and oxygenation level. In order to delineate more precisely the restrictions imposed by water oxygenation on fish metabolic performance we determined the limiting oxygen concentration curves at each experimental temperature. We followed up by modelling the bass active metabolic rate (AMR) and metabolic scope (MS) as functions of both ambient temperature and oxygenation. These mathematical models allowed the characterisation of the controlling and limiting effects of water temperature and oxygen content on the metabolic capacity of the species. Thus, AMR at 10, 15 and 20°C were estimated at 65, 160 and 360 mg O 2 kg -1 h -1, respectively. However, at higher temperature (25°C) AMR dropped slightly (to 340 mg O 2 kg -1 h -1). Bass MS increased by a factor of 9 between 10 and 20°C, but diminished at higher temperatures. The present study contributes to our current understanding of the influences of environmental factors on the metabolism of sea bass and provides a bioenergetic basis for a study of how environmental constraints govern the spatial and temporal distribution pattern of this species.
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Kantoussan, Justin; Ndiaye, Papa; Thiaw, Omar Thiom; Albaret, Jean-Jacques
2012-01-01
The black-chinned tilapia Sarotherodon melanotheron is a marine teleost characterised by an extreme euryhalinity. However, beyond a certain threshold at very high salinity, the species exhibits impaired growth and precocious reproduction. In this study, the relationships between reproductive parameters, environmental salinity and condition factor were investigated in wild populations of this species that were sampled in two consecutive years (2003 and 2004) from three locations in Senegal with different salinities: Guiers lake (freshwater, 0 psu), Hann bay (seawater, 37 psu) and Saloum estuary (hypersaline water, 66–127 psu). The highest absolute fecundity and spawning weight were recorded in seawater by comparison to either freshwater or hypersaline water whereas the poorest condition factors were observed in the most saline sampling site. These results reflect higher resource allocation to the reproduction due to the lowest costs of adaptation to salinity in seawater (the natural environment of this species) rather than differences in food resources at sites and/or efficiency at foraging and prey availability. Fecundities, oocyte size as well as spawning weight were consistent from year to year. However, the relative fecundity in the Saloum estuary varied significantly between the dry and rainy raisons with higher values in the wet season, which seems to reflect seasonal variations in environmental salinity. Such a reproductive tactic of producing large amounts of eggs in the rainy season when the salinity in the estuary was lower, would give the fry a better chance at survival and therefore assures a high larval recruitment. An inverse correlation was found between relative fecundity and oocyte size at the two extreme salinity locations, indicating that S. melanotheron has different reproductive strategies in these ecosystems. The adaptive significance of these two reproductive modes is discussed in regard to the heavy osmotic constraint imposed by extreme salinities and high inter-specific competition. PMID:22253726
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Vargas-Chacoff, L; Saavedra, E; Oyarzún, R; Martínez-Montaño, E; Pontigo, J P; Yáñez, A; Ruiz-Jarabo, I; Mancera, J M; Ortiz, E; Bertrán, C
2015-12-01
In this study we assessed the influence of three different environmental salinities (5, 15 and 31 psu during 90 days) on growth, osmoregulation, energy metabolism and digestive capacity in juveniles of the Notothenioid fish Eleginops maclovinus. At the end of experimental time samples of plasma, liver, gill, intestine, kidney, skeletal muscle, stomach and pyloric caeca were obtained. Growth, weight gain, hepatosomatic index and specific growth rate increased at 15 and 31 psu and were lower at 5 psu salinity. Gill Na(+), K(+)-ATPase (NKA) activity presented a "U-shaped" relationship respect to salinity, with its minimum rates at 15 psu, while this activity correlated negatively with salinity at both anterior and posterior intestinal portions. No significant changes in NKA activity were observed in kidney or mid intestine. Large changes in plasma, metabolite levels and enzymatic activities related to energy metabolism in liver, gill, intestine, kidney and muscle were generally found in the groups exposed to 5 and 31 psu compared to the 15 psu group. Only the pepsin activity (digestive enzymes) assessed enhanced with environmental salinity, while pyloric caeca trypsin/chymotrypsin ratio decreased. This study suggests that juvenile of E. maclovinus presents greater growth near its iso-osmotic point (15 psu) and hyperosmotic environment (31 psu). Acclimation to low salinity increased the osmoregulatory expenditure as seen by the gill and anterior intestine results, while at high salinity, branchial osmoregulatory activity was also enhanced. This requires the mobilization of lipid stores and amino acids, thereby holding the growth of fish back. The subsequent reallocation of energy sources was not sufficient to maintain the growth rate of fish exposed to 5 psu. Thus, E. maclovinus juveniles present better growth efficiencies in salinities above the iso-osmotic point and hyperosmotic environment of this species, showing their best performance at 15 psu as seen by the main osmoregulatory and energy metabolism enzymatic activities.
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Willett, Christopher S; Burton, Ronald S
2002-08-01
Diverse organisms regulate concentrations of intracellular organic osmolytes in response to changes in environmental salinity or desiccation. In marine crustaceans, accumulation of high concentrations of proline is a dominant component of response to hyperosmotic stress. In the euryhaline copepod Tigriopus californicus, synthesis of proline from its metabolic precursor glutamate is tightly regulated by changes in environmental salinity. Here, for the first time in a marine invertebrate, the genes responsible for this pathway have been cloned and characterized. The two proteins display the sequence features of homologous enzymes identified from other eukaryotes. One of the cloned genes, delta1-pyrroline-5-carboxylase reductase (P5CR), is demonstrated to have the reductase enzyme activity when expressed in proline-auxotroph bacteria, while the second, delta1-pyrroline-5-carboxylase synthase (P5CS), does not rescue proline-auxotroph bacteria. In contrast to results from higher plants, neither levels of P5CS nor P5CR mRNAs increase in response to salinity stress in T. californicus. Hence, regulation of proline synthesis during osmotic stress in T. californicus is likely mediated by some form of post-transcriptional regulation of either P5CS or P5CR. Understanding the regulation this pathway may elucidate the mechanisms limiting the salinity ranges of marine taxa. Copyright 2002 Elsevier Science Inc.
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Namsaraev, Zorigto; Samylina, Olga; Sukhacheva, Marina; Borisenko, Gennadii; Sorokin, Dimitry Y; Tourova, Tatiana
2018-04-16
Bitter-1 is a shallow hypersaline soda lake in Kulunda Steppe (Altai region, Russia). During a study period between 2005 and 2016, the salinity in the littoral area of the lake fluctuated within the range from 85 to 400 g/L (in July of each year). Light-dependent nitrogen fixation occurred in this lake up to the salt-saturating conditions. The rates increased with a decrease in salinity, both under environmental conditions and in laboratory simulations. The salinities below 100 g/L were favorable for light-dependent nitrogen fixation, while the process was dramatically inhibited above 200 g/L salts. The analysis of nifH genes in environmental samples and in enrichment cultures of diazotrophic phototrophs suggested that anaerobic fermenting and sulfate-reducing bacteria could participate in the dark nitrogen fixation process up to soda-saturating conditions. However, we cannot exclude the possibility that haloalkaliphilic nonheterocystous cyanobacteria (Euhalothece sp. and Geitlerinema sp.) and anoxygenic purple sulfur bacteria (Ectothiorhodospira sp.) might also play a role in the process at light conditions. The heterocystous cyanobacterium Nodularia sp. develops at low salinity (below 80 g/L) that is not characteristic for Bitter-1 Lake and thus does not make a significant contribution to the nitrogen fixation in this lake.
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López-Hernández, Karla M; Pardío-Sedas, Violeta T; Lizárraga-Partida, Leonardo; Williams, José de J; Martínez-Herrera, David; Flores-Primo, Argel; Uscanga-Serrano, Roxana; Rendón-Castro, Karla
2015-02-15
The influence of environmental parameters on the total and pathogenic Vibrio parahaemolyticus seasonal densities in American oysters (Crassostrea virginica) was evaluated for 1 year. Harvesting site A yielded the highest mean densities of V. parahaemolyticus tlh+, tdh+/trh-, tdh-/trh+ and tdh+/trh+ during spring season at 2.57, 1.74, 0.36, and -0.40 log10 MPN/g, respectively, and tdh+/orf8+ during winter season (0.90 log10 MPN/g). V. parahaemolyticus tlh+ densities were associated to salinity (R(2)=0.372, P<0.022), tdh+/trh+ to turbidity (R(2)=0.597, P<0.035), and orf8+ to temperature, salinity, and pH (R(2)=0.964, P<0.001). The exposure to salinity and temperature conditions during winter and spring seasons regulated the dynamics of V. parahaemolyticus harboring potentially pathogenic genotypes within the oyster. The adaptive response of V. parahaemolyticus to seasonal environmental changes may lead to an increase in survival and virulence, threatening the seafood safety and increasing the risk of illness. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Sun, Yanling; Kong, Xiangpei; Li, Cuiling; Liu, Yongxiu; Ding, Zhaojun
2015-01-01
Plants are exposed to various environmental stresses during their life cycle such as salt, drought and cold. Natural variation mediated plant growth adaptation has been employed as an effective approach in response to the diverse environmental cues such as salt stress. However, the molecular mechanism underlying this process is not well understood. In the present study, a collection of 82 Arabidopsis thaliana accessions (ecotypes) was screened with a view to identify variation for salinity tolerance. Seven accessions showed a higher level of tolerance than Col-0. The young seedlings of the tolerant accessions demonstrated a higher K+ content and a lower Na+/K+ ratio when exposed to salinity stress, but its Na+ content was the same as that of Col-0. The K+ transporter genes AtHAK5, AtCHX17 and AtKUP1 were up-regulated significantly in almost all the tolerant accessions, even in the absence of salinity stress. There was little genetic variation or positive transcriptional variation between the selections and Col-0 with respect to Na+-related transporter genes, as AtSOS genes, AtNHX1 and AtHKT1;1. In addition, under salinity stress, these selections accumulated higher compatible solutes and lower reactive oxygen species than did Col-0. Taken together, our results showed that natural variation in salinity tolerance of Arabidopsis seems to have been achieved by the strong capacity of K+ retention. PMID:25993093
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Miranda, Nelson A F; Perissinotto, Renzo; Appleton, Christopher C
2011-01-01
Estuaries and coastal lakes receive little attention despite being heavily invaded by non-indigenous invasive species (NIS). In these situations, studies of population dynamics in invaded habitats can provide valuable insights into how NIS interact with new environments. Tarebia granifera is a prosobranch gastropod from south-east Asia which has invaded other sub-tropical parts of the world. This study addresses whether a small number of key environmental factors influences gastropod communities, and specifically how the population density and size structure of T. granifera were influenced by environmental change in estuaries and coastal lakes in southern Africa. T. granifera's density, number of brooded juveniles and size structure were measured at the St. Lucia Estuary, Mgobozeleni Estuary, Lake Sibaya and Lake Nhlange. Size structure was classified according to shell height (SH). All dissected individuals were found to be female and free from trematode infection. Salinity, water depth, temperature, and pH were the main factors correlated with population density of gastropod communities. T. granifera often reached densities well over 1000 ind. m(-2), displacing indigenous gastropods and becoming a dominant component of the benthic community. T. granifera successfully invaded estuaries despite frequent exposure to high salinity and desiccation, which could together eliminate >97% of the population. The persistence of T. granifera was ensured due to its high fecundity and the environmental tolerance of large adults (20-30 mm SH) which carried an average of 158±12.8 SD brooded juveniles. Repeat introductions were not essential for the success of this parthenogenetic NIS. There is a need for a broader study on the reproductive biology of T. granifera (including the previously overlooked "brood pouch ecology"), which affects population dynamics and may be relevant to other parthenogenetic NIS, such as Melanoides tuberculata and Potamopyrgus antipodarum.
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Wang, Youji; Hu, Menghong; Cheung, S G; Shin, P K S; Lu, Weiqun; Li, Jiale
2012-06-01
The effects of chronic hypoxia and low salinity on anti-predatory responses of the green-lipped mussel Perna viridis were investigated. Dissolved oxygen concentrations ranged from hypoxic to normoxic (1.5 ± 0.3 mg l(-1), 3.0 ± 0.3 mg l(-1) and 6.0 ± 0.3 mg l(-1)), and salinities were selected within the variation during the wet season in Hong Kong coastal waters (15‰, 20‰, 25‰ and 30‰). The dissolved oxygen and salinity significantly affected some anti-predatory responses of mussel, including byssus production, shell thickness and shell weight, and the adductor diameter was only significantly affected by salinity. Besides, interactive effects of dissolved oxygen and salinity on the byssus production and shell thickness were also observed. In hypoxic and low salinity conditions, P. viridis produced fewer byssal threads, thinner shell and adductor muscle, indicating that hypoxia and low salinity are severe environmental stressors for self-defence of mussel, and their interactive effects further increase the predation risk. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.
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Calcium Signaling during Salt Stress and in the Regulation of Ion Homeostasis.
Manishankar, P; Wang, N; Köster, P; Alatar, A A; Kudla, J
2018-05-24
Soil composition largely defines the living conditions of plants and represents one of their most relevant, dynamic and complex environmental cues. The effective concentrations of many either tolerated or essential ions and compounds in the soil usually differ from the optimum that would be most suitable for plants. In this regard, salinity - caused by excess of NaCl - represents a widespread adverse growth condition but also shortage of ions like K+, NO3- and Fe2+ restrains plant growth. During the past years many components and mechanisms that function in the sensing and establishment of ion homeostasis have been identified and characterized. Here, we reflect on recent insights that extended our understanding of components and mechanisms, which govern and fine-tune plant salt stress tolerance and ion homeostasis. We put special emphasis on mechanisms that allow for interconnection of the salt overly sensitivity pathway with plant development and discuss newly emerging functions of Ca2+ signaling in salinity tolerance. Moreover, we review and discuss accumulating evidence for a central and unifying role of Ca2+ signaling and Ca2+ dependent protein phosphorylation in regulating sensing, uptake, transport and storage processes of various ions. Finally, based on this cross-field inventory, we deduce emerging concepts and arising questions for future research.
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NASA Astrophysics Data System (ADS)
Yu, Ok Hwan; Lee, Hyung-Gon; Lee, Jae-Hac
2012-12-01
We compared environmental effects on the macrobenthic community of the Han River Estuary in summer, when freshwater input from the Han River increased, and in spring, when freshwater input decreased. Field samples were taken from the upper region of the Shingok reservoir to the southern area of Ganghwado at 18 sampling sites after rainy (August 2006) and dry (March 2007) seasons. Macrobenthic fauna were collected using a Van Veen Grab (0.025 m2 and 0.1 m2) and environmental factors were measured simultaneously. Dominant species of macrobenthic fauna and the macrobenthic community were divided into two areas, the area of the Han River with no salinity (< 0.1 psu) and the southern part of Ganghwado with salinity (> 20 psu). The dominant species Byblis japonicus appeared at Junruri in the dry season. The distributions of two polychaetes, Hediste japonica and Nephtys caeca, were divided into the lower and upper areas of the Singok submerged weir. BIO-ENV (the matching of biotic to environmental patterns) analysis revealed that salinity was the most important factor affecting macrobenthic communities in the Han River Estuary, with other factors such as sediment grain size, bottom dissolved oxygen, and total organic carbon of sediment being secondary.
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Davidson, Keith; Bolch, Christopher J. S.; Brand, Tim D.; Narayanaswamy, Bhavani E.
2012-01-01
Phytoplankton underpin the marine food web in shelf seas, with some species having properties that are harmful to human health and coastal aquaculture. Pressures such as climate change and anthropogenic nutrient input are hypothesized to influence phytoplankton community composition and distribution. Yet the primary environmental drivers in shelf seas are poorly understood. To begin to address this in North Western European waters, the phytoplankton community composition was assessed in light of measured physical and chemical drivers during the “Ellett Line” cruise of autumn 2001 across the Scottish Continental shelf and into adjacent open Atlantic waters. Spatial variability existed in both phytoplankton and environmental conditions, with clear differences not only between on and off shelf stations but also between different on shelf locations. Temperature/salinity plots demonstrated different water masses existed in the region. In turn, principal component analysis (PCA), of the measured environmental conditions (temperature, salinity, water density and inorganic nutrient concentrations) clearly discriminated between shelf and oceanic stations on the basis of DIN∶DSi ratio that was correlated with both salinity and temperature. Discrimination between shelf stations was also related to this ratio, but also the concentration of DIN and DSi. The phytoplankton community was diatom dominated, with multidimensional scaling (MDS) demonstrating spatial variability in its composition. Redundancy analysis (RDA) was used to investigate the link between environment and the phytoplankton community. This demonstrated a significant relationship between community composition and water mass as indexed by salinity (whole community), and both salinity and DIN∶DSi (diatoms alone). Diatoms of the Pseudo-nitzschia seriata group occurred at densities potentially harmful to shellfish aquaculture, with the potential for toxicity being elevated by the likelihood of DSi limitation of growth at most stations and depths. PMID:22479533
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Untersuchungen zum Harnsäuremetabolismus von Littorina littorea (Gastropoda)
NASA Astrophysics Data System (ADS)
Heil, K. P.; Eichelberg, D.
1983-12-01
Periwinkles, as typical inhabitants of sea-shores, are subjected to extreme changes of environmental conditions, which affect their excretion. In Littorina littorea uric acid, urea and ammonium were detected particularly in the kidney, but the only metabolite excreted was ammonium. Only the concentration of uric acid was dependent on the availability of water; decreasing periods of submersion during low tide and raised salinities caused a higher concentration of uric acid, while increasing periods of submersion and lowered salinities effected the opposite. Transfer of periwinkles within their intertidal habitat and laboratory experiments to test the effect of salinity showed that the concentration of uric acid in the kidney is adaptable. The dependence of uric acid concentration in the kidney on environmental conditions and the ammoniotelic excretion of L. littorea are discussed with regard to its particular living conditions. It is suggested that uric acid serves as nitrogen depot and has a particular function in osmoregulation.
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Stewart, R.E.; Kantrud, H.A.
1972-01-01
Measurements of specific conductance provide an adequate indication of the average salinity of surface waters in natural ponds and lakes of the northern .prairie region. Yearly and seasonal variations in specific conductance were much greater in brackish and subsaline wetlands than in fresh-water areas. The principal vegetational types. Land-use practices of varying brackish to saline wetlands were sulfates and chlorides of sodium and magnesium. In less saline waters, carbonate and bicarbonate salts of calcium and potassium were of greater importance, but as salinity increased, the proportion of these compounds decreased rapidly.A major environmental factor controlling the establishment of marsh and aquatic vegetation is the permanence of surface water. Permanence is a measure of the extent to which surface water persists at a given site. Varying degrees of water permanence during the growing season led to the establishment of distinct vegetational types, which were differentiated primarily on the 'basis of community structure or life form of the dominant vegetation.Salinity of surface waters was closely correlated with differences in species composition of plant communities found in the principal vegetational types. Land-use practices of varying degrees of intensity also had a secondary influence on species composition. Since an unstable water chemistry is characteristic of most prairie ponds and lakes, it is more reliable to use the plant communities as indicators of average salinity than to use single measurements of specific conductance.Characteristic species of wetland vegetational types occupied the central deeper parts of pond and lake basins or occurred as concentric peripheral bands. The wetland vegetational types are wetland low-prairie, wet-meadow, shallow-marsh emergent, deep-marsh emergent, fen emergent, submerged and floating, natural drawdown, cropland drawdown, and cropland tillage vegetation. Combinations of species (plant associations) within these vegetational types were placed in one of six salinity categories designated as fresh, slightly brackish, moderately brackish, brackish, subsaline, and saline. Salt tolerance apparently varied greatly among the various marsh and aquatic plants since the num'ber of species represented in moderately brackish to saline communities decreased markedly with increased salinity of the surface water environment.
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Israël, Natascha M.D.; VanLandeghem, Matthew M.; Denny, Shawn; Ingle, John; Patino, Reynaldo
2014-01-01
Prymnesium parvum (golden alga, GA) is a toxigenic harmful alga native to marine ecosystems that has also affected brackish inland waters. The first toxic bloom of GA in the western hemisphere occurred in the Pecos River, one of the saltiest rivers in North America. Environmental factors (water quality) associated with GA occurrence in this basin, however, have not been examined. Water quality and GA presence and abundance were determined at eight sites in the Pecos River basin with or without prior history of toxic blooms. Sampling was conducted monthly from January 2012 to July 2013. Specific conductance (salinity) varied spatiotemporally between 4408 and 73,786 mS/cm. Results of graphical, principal component (PCA), and zero-inflated Poisson (ZIP) regression analyses indicated that the incidence and abundance of GA are reduced as salinity increases spatiotemporally. LOWESS regression and correlation analyses of archived data for specific conductance and GA abundance at one of the study sites retrospectively confirmed the negative association between these variables. Results of PCA also suggested that at <15,000 mS/cm, GA was present at a relatively wide range of nutrient (nitrogen and phosphorus) concentrations whereas at higher salinity, GA was observed only at mid-to-high nutrient levels. Generally consistent with earlier studies, results of ZIP regression indicated that GA presence is positively associated with organic phosphorus and in samples where GA is present, GA abundance is positively associated with organic nitrogen and negatively associated with inorganic nitrogen. This is the first report of an inverse relation between salinity and GA presence and abundance in riverine waters and of interaction effects of salinity and nutrients in the field. These observations contribute to a more complete understanding of environmental conditions that influence GA distribution in inland waters.
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NASA Astrophysics Data System (ADS)
Li, Siping; He, Feng; Wen, Haishen; Li, Jifang; Si, Yufeng; Liu, Mingyuan; He, Huiwen; Huang, Zhengju
2017-04-01
Increasingly arisen environmental constraints may contribute to heritable phenotypic variation including methylation changes, which can help the animals with development, growth and survival. In this study, we assessed the DNA methylation levels in three tissues (gonad, kidney and gill) of half smooth tongue sole under the salinity stress. The methylation-sensitive amplification polymorphism (MSAP) technique was applied to illustrate the regulation of epigenetic mechanism in environmental stimuli. Fish were subjected to 15 salinity treatment for 7 and 60 days, respectively. A total of 11259 fragments were amplified with 8 pairs of selective primers. The levels of methylated DNA in different tissues of females and males without salinity stress were analyzed, which were 32.76% and 47.32% in gonad; 38.13% and 37.69% in kidney; 37.58% and 34.96% in gill, respectively. In addition, the significant difference was observed in gonad between females and males, indicating that discrepant regulation in gonadal development and differentiation may involve sex-related genes. Further analysis showed that total and hemi-methylation were significantly decreased under 15 salinity for 7 days, probably resulting in up-regulating salt-tolerance genes expression to adjust salt changing. With the adjustment for 60 days, total and hemi-methylation prominently went back to its normal levels to obtain equilibrium. Particularly, full methylation levels were steady along with salinity stress to maintain the stability of gene expression. Additionally, the data showed that gonads in females and gills in males were superior in adaptability. As a result, DNA methylation regulates tissue- specific epiloci, and may respond to salinity stress by regulating gene expression to maintain animal survival and activity.
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Brennan, Reid S; Hwang, Ruth; Tse, Michelle; Fangue, Nann A; Whitehead, Andrew
2016-06-01
Regulation of internal ion homeostasis is essential for fishes inhabiting environments where salinities differ from their internal concentrations. It is hypothesized that selection will reduce energetic costs of osmoregulation in a population's native osmotic habitat, producing patterns of local adaptation. Killifish, Fundulus heteroclitus, occupy estuarine habitats where salinities range from fresh to seawater. Populations inhabiting an environmental salinity gradient differ in physiological traits associated with acclimation to acute salinity stress, consistent with local adaptation. Similarly, metabolic rates differ in populations adapted to different temperatures, but have not been studied in regard to salinity. We investigated evidence for local adaptation between populations of killifish native to fresh and brackish water habitats. Aerobic scope (the difference between minimum and maximum metabolic rates), excess post-exercise oxygen consumption, and swimming performance (time and distance to reach exhaustion) were used as proxies for fitness in fresh and brackish water treatments. Swimming performance results supported local adaptation; fish native to brackish water habitats performed significantly better than freshwater-native fish at high salinity while low salinity performance was similar between populations. However, results from metabolic measures did not support this conclusion; both populations showed an increase in resting metabolic rate and a decrease of aerobic scope in fresh water. Similarly, excess post-exercise oxygen consumption was higher for both populations in fresh than in brackish water. While swimming results suggest that environmentally dependent performance differences may be a result of selection in divergent osmotic environments, the differences between populations are not coupled with divergence in metabolic performance. Copyright © 2016 Elsevier Inc. All rights reserved.
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Hydraulic redistribution: limitations for plants in saline soils.
Bazihizina, Nadia; Veneklaas, Erik J; Barrett-Lennard, Edward G; Colmer, Timothy D
2017-10-01
Hydraulic redistribution (HR), the movement of water from wet to dry patches in the soil via roots, occurs in different ecosystems and plant species. By extension of the principle that HR is driven by gradients in soil water potential, HR has been proposed to occur for plants in saline soils. Despite the inherent spatial patchiness and salinity gradients in these soils, the lack of direct evidence of HR in response to osmotic gradients prompted us to ask the question: are there physical or physiological constraints to HR for plants in saline environments? We propose that build-up of ions in the root xylem sap and in the leaf apoplast, with the latter resulting in a large predawn disequilibrium of water potential in shoots compared with roots and soil, would both impede HR. We present a conceptual model that illustrates how processes in root systems in heterogeneous salinity with water potential gradients, even if equal to those in non-saline soils, will experience a dampened magnitude of water potential gradients in the soil-plant continuum, minimizing or preventing HR. Finally, we provide an outlook for understanding the relevance of HR for plants in saline environments by addressing key research questions on plant salinity tolerance. © 2017 John Wiley & Sons Ltd.
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Bhusal, Prabhat; Rahiri, Jamie Lee; Sua, Bruce; McDonald, Jessica E; Bansal, Mahima; Hanning, Sara; Sharma, Manisha; Chandramouli, Kaushik; Harrison, Jeff; Procter, Georgina; Andrews, Gavin; Jones, David S; Hill, Andrew G; Svirskis, Darren
2018-06-01
An understanding of biological fluids at the site of administration is important to predict the fate of drug delivery systems in vivo. Little is known about peritoneal fluid; therefore, we have investigated this biological fluid and compared it to phosphate-buffered saline, a synthetic media commonly used for in vitro evaluation of intraperitoneal drug delivery systems. Human peritoneal fluid samples were analysed for electrolyte, protein and lipid levels. In addition, physicochemical properties were measured alongside rheological parameters. Significant inter-patient variations were observed with regard to pH (p < 0.001), buffer capacity (p < 0.05), osmolality (p < 0.001) and surface tension (p < 0.05). All the investigated physicochemical properties of peritoneal fluid differed from phosphate-buffered saline (p < 0.001). Rheological examination of peritoneal fluid demonstrated non-Newtonian shear thinning behaviour and predominantly exhibited the characteristics of an entangled network. Inter-patient and inter-day variability in the viscosity of peritoneal fluid was observed. The solubility of the local anaesthetic lidocaine in peritoneal fluid was significantly higher (p < 0.05) when compared to phosphate-buffered saline. Interestingly, the dissolution rate of lidocaine was not significantly different between the synthetic and biological media. Importantly, and with relevance to intraperitoneal drug delivery systems, the sustained release of lidocaine from a thermosensitive gel formulation occurred at a significantly faster rate into peritoneal fluid. Collectively, these data demonstrate the variation between commonly used synthetic media and human peritoneal fluid. The differences in drug release rates observed illustrate the need for bio-relevant media, which ultimately would improve in vitro-in vivo correlation.
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Mapping the spatial distribution of subsurface saline material in the Darling River valley
NASA Astrophysics Data System (ADS)
Triantafilis, John; Buchanan, Sam Mostyn
2010-02-01
In the Australian landscape larg stores of soluble salt are present naturally. In many cases it is attributable to salts entrapped as marine sediment in earlier geological time. At the district level, the need for information on the presence of saline subsurface material is increasing, particularly for its application to salinity hazard assessment and environmental management. This is the case in irrigated areas, where changes in hydrology can result in secondary salinisation. To reduce the expense, environmental studies use a regression relationship to make use of more readily observed measurements (e.g. electromagnetic (EM) data) which are strongly correlated with the variable of interest. In this investigation a methodology is outlined for mapping the spatial distribution of average subsurface (6-12 m) salinity (EC e — mS m - 1 ) using an environmental correlation with EM34 survey data collected across the Bourke Irrigation District (BID) in the Darling River valley. The EM34 is used in the horizontal dipole mode at coil configurations of 10 (EM34-10), 20 (EM34-20), and 40 (EM34-40). A multiple-linear regression (MLR) relationship is established between average subsurface EC e and the three EM34 signal data using a forward modeling stepwise linear modeling approach. The spatial distribution of average subsurface salinity generally reflects the known surface expression of point-source salinisation and provides information for future environmental monitoring and natural resource management. The generation of EM34 data on various contrived grids (i.e. 1, 1.5, 2. 2.5 and 3 km) indicates that in terms of accuracy, the data available on the 0.5 (RMSE = 188) and 1 km (RMSE = 283) grid are best, with the least biased predictions achieved using 1 (ME = - 1) and 2 km (ME = 12) grids. Viewing the spatial distribution of subsurface saline material showed that the 0.5 km spacing is optimal, particularly in order to account for short-range spatial variation between various physiographic units. The Relative Improvement (RI) shows that increasing EM grids from 1, 1.5, 2, 2.5 to 3 km gave RI of - 53, - 100%, - 107%, - 128% and - 140%, respectively. We conclude that at a minimum a 1 km grid is needed for reconnaissance EM34 surveying.
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NASA Astrophysics Data System (ADS)
Shamkhali Chenar, S.; Deng, Z.
2017-12-01
Pathogenic viruses pose a significant public health threat and economic losses to shellfish industry in the coastal environment. Norovirus is a contagious virus and the leading cause of epidemic gastroenteritis following consumption of oysters harvested from sewage-contaminated waters. While it is challenging to detect noroviruses in coastal waters due to the lack of sensitive and routine diagnostic methods, machine learning techniques are allowing us to prevent or at least reduce the risks by developing effective predictive models. This study attempts to develop an algorithm between historical norovirus outbreak reports and environmental parameters including water temperature, solar radiation, water level, salinity, precipitation, and wind. For this purpose, the Random Forests statistical technique was utilized to select relevant environmental parameters and their various combinations with different time lags controlling the virus distribution in oyster harvesting areas along the Louisiana Coast. An Artificial Neural Networks (ANN) approach was then presented to predict the outbreaks using a final set of input variables. Finally, a sensitivity analysis was conducted to evaluate relative importance and contribution of the input variables to the model output. Findings demonstrated that the developed model was capable of reproducing historical oyster norovirus outbreaks along the Louisiana Coast with the overall accuracy of than 99.83%, demonstrating the efficacy of the model. Moreover, the increase in water temperature, solar radiation, water level, and salinity, and the decrease in wind and rainfall are associated with the reduction in the model-predicted risk of norovirus outbreak according to sensitivity analysis results. In conclusion, the presented machine learning approach provided reliable tools for predicting potential norovirus outbreaks and could be used for early detection of possible outbreaks and reduce the risk of norovirus to public health and the seafood industry.
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Sable, Helen J. K.; Monaikul, Supida; Poon, Emily; Eubig, Paul A.; Schantz, Susan L.
2010-01-01
Polychlorinated biphenyls (PCBs) are environmental neurotoxicants known to affect the brain dopaminergic (DA) system. This project investigated whether developmental exposure to PCBs would alter the discriminative stimulus effects of psychostimulant drugs known to act on the DA system. Female Long-Evans rats were orally exposed to 0, 3, or 6 mg/kg/day of an environmentally relevant PCB mixture from four weeks prior to breeding through weaning of their litters on PND 21. When they reached adulthood one male and female/litter were trained to discriminate cocaine (10.0 mg/kg, IP) from saline by repeatedly pairing cocaine injections with reinforcement on one operant response lever, and saline injections with reinforcement on the other lever. After response training, generalization tests to four lower doses of cocaine (7.5, 5.0, 2.5, and 1.25 mg/kg, IP) and to amphetamine (1.0, 0.5, 0.25, and 0.125 mg/kg, IP) were given two days/week, with additional training dose days in-between. Percent responding of the PCB-exposed rats on the cocaine-paired lever was significantly higher than that of controls for the highest generalization dose of cocaine, and lower than that of controls for the highest dose of amphetamine. Response rate and percent responding on the cocaine lever did not differ among the exposure groups on the days when the training dose of cocaine was given, suggesting the generalization test results were not due to pre-existing differences in discrimination ability or rate of responding. These findings suggest developmental PCB exposure can alter the interoceptive cues of psychostimulants. PMID:20933596
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Environmental Drivers of the Canadian Arctic Megabenthic Communities
Roy, Virginie; Iken, Katrin; Archambault, Philippe
2014-01-01
Environmental gradients and their influence on benthic community structure vary over different spatial scales; yet, few studies in the Arctic have attempted to study the influence of environmental gradients of differing spatial scales on megabenthic communities across continental-scales. The current project studied for the first time how megabenthic community structure is related to several environmental factors over 2000 km of the Canadian Arctic, from the Beaufort Sea to northern Baffin Bay. Faunal trawl samples were collected between 2007 and 2011 at 78 stations from 30 to 1000 m depth and patterns in biomass, density, richness, diversity, and taxonomic composition were examined in relation to indirect/spatial gradients (e.g., depth), direct gradients (e.g., bottom oceanographic variables), and resource gradients (e.g., food supply proxies). Six benthic community types were defined based on their biomass-based taxonomic composition. Their distribution was significantly, but moderately, associated with large-scale (100–1000 km) environmental gradients defined by depth, physical water properties (e.g., bottom salinity), and meso-scale (10–100 km) environmental gradients defined by substrate type (hard vs. soft) and sediment organic carbon content. We did not observe a strong decline of bulk biomass, density and richness with depth or a strong increase of those community characteristics with food supply proxies, contrary to our hypothesis. We discuss how local- to meso-scale environmental conditions, such as bottom current regimes and polynyas, sustain biomass-rich communities at specific locations in oligotrophic and in deep regions of the Canadian Arctic. This study demonstrates the value of considering the scales of variability of environmental gradients when interpreting their relevance in structuring of communities. PMID:25019385
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NASA Astrophysics Data System (ADS)
Darnell, M. Z.
2016-02-01
Female blue crabs undertake a critical spawning migration seaward, migrating from low-salinity mating habitat to high-salinity waters of the lower estuaries and coastal ocean, where larval survival is highest. This migration occurs primarily through ebb tide transport, driven by an endogenous circatidal rhythm in vertical swimming that is modulated by behavioral responses to environmental cues. Blue crabs are typically considered an estuarine species and fisheries are managed on a state-by-state basis. Yet recent evidence from state and regional fishery independent survey programs suggests that the spawning migration can take females substantial distances offshore (>150 km), and that offshore waters are important spawning grounds for female blue crabs in the Gulf of Mexico. This is especially true in areas where freshwater inflow is high, resulting in low estuarine and coastal salinities. In low-salinity, high-inflow areas (e.g., Louisiana), spawning occurs further offshore while in high-salinity, low-inflow areas (e.g., South Texas), spawning takes place primarily within the estuary. Regional patterns in spawning locations both inshore and offshore are driven by interactions between behavioral mechanisms and local oceanographic conditions during the spawning migration. These environmentally driven differences in spawning locations have implications for larval survival and population connectivity, and emphasize the need for interjurisdictional assessment and management of the blue crab spawning stock.
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NASA Astrophysics Data System (ADS)
Akin, S.; Buhan, E.; Winemiller, K. O.; Yilmaz, H.
2005-09-01
Spatial and temporal variation in fish assemblage structure of Koycegiz Lagoon-Estuarine System (KLES), located on the northwestern Turkish coast of Mediterranean, was investigated along an estuarine gradient where salinity ranged from 5 in upper reaches to 40 in lower reaches during October 1993-September 1994. Throughout the study, 42 species, consisting of marine (25), marine-estuarine-dependent (12), freshwater (3), catadromous (1), and estuarine resident (1) forms, were collected in trammel nets. Although species richness of marine species was greater than that of other groups, numerical contribution by marine species to the total catch was only 16%. Tilapia spp., the most abundant species mostly during summer and early spring at upper reaches, contributed 17% of the total samples. Among the seven species of Mugilidae, which contributed 42% of the total catch, Mugil cephalus, Liza aurata, and Liza salines contributed 10, 13, and 10% of the total catch, respectively. Consistent with findings from other studies, species richness and abundance were highest during late spring and summer and the lowest during winter and early spring. Samples from sites at or near the sea had more marine species. Samples from upper reaches had more freshwater and marine-estuarine-dependent species. Canonical correspondence analysis (CCA) indicated that salinity and turbidity were the most important environmental parameters affecting fishes. Sites near the sea were associated with high salinity and low turbidity, and sites in upper reaches had low salinity and high turbidity. Thus, the pattern observed in fish assemblage structure appears to be strongly influenced by species' responses to dominant salinity and turbidity gradients.
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Effects of Salinity on Oil Spill Dispersant Toxicity in Estuarine Organisms
NASA Astrophysics Data System (ADS)
Eckmann, C. A.
2016-02-01
Chemical dispersants can be a useful tool to mitigate oil spills, but the potential risks to sensitive estuarine species should be carefully considered. To improve the decision making process, more information is needed regarding the effects of oil spill dispersants on the health of coastal ecosystems under variable environmental conditions such as salinity. The two oil dispersants used in this study were Corexit ® 9500 and Finasol ® OSR 52. Corexit ® 9500 was the primary dispersant used during the 2010 Deepwater Horizon oil spill event, while Finasol® OSR 52 is another dispersant approved for oil spill response in the U.S., yet considerably less is known regarding its toxicity to estuarine species. The grass shrimp, Palaemonetes pugio, was used as a model estuarine species. It is a euryhaline species that tolerates salinities from brackish to full strength seawater. Adult and larval life stages were tested with each dispersant at three salinities, 5ppt, 20ppt, and 30ppt. Median acute lethal toxicity thresholds were calculated. Lipid peroxidation assays were conducted on surviving shrimp to investigate sublethal effects. The toxicity of both dispersants was significantly influenced by salinity, with greatest toxicity observed at the lowest salinity tested. Larval shrimp were significantly more sensitive than adult shrimp to both dispersants, and both life stages were significantly more sensitive to Finasol than to Corexit. Furthermore, significant sublethal effects were seen at higher concentrations of both dispersants compared to the control. These data will enable environmental managers to make informed decisions regarding dispersant use in future oil spills.
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Effects of Salinity on Oil Spill Dispersant Toxicity in Estuarine Organisms
NASA Astrophysics Data System (ADS)
Eckmann, C. A.
2015-12-01
Chemical dispersants can be a useful tool to mitigate oil spills, but the potential risks to sensitive estuarine species should be carefully considered. To improve the decision making process, more information is needed regarding the effects of oil spill dispersants on the health of coastal ecosystems under variable environmental conditions such as salinity. The two oil dispersants used in this study were Corexit ® 9500 and Finasol ® OSR 52. Corexit ® 9500 was the primary dispersant used during the 2010 Deepwater Horizon oil spill event, while Finasol® OSR 52 is another dispersant approved for oil spill response in the U.S., yet considerably less is known regarding its toxicity to estuarine species. The grass shrimp, Palaemonetes pugio, was used as a model estuarine species. It is a euryhaline species that tolerates salinities from brackish to full strength seawater. Adult and larval life stages were tested with each dispersant at three salinities, 5ppt, 20ppt, and 30ppt. Median acute lethal toxicity thresholds were calculated. Lipid peroxidation assays were conducted on surviving shrimp to investigate sublethal effects. The toxicity of both dispersants was significantly influenced by salinity, with greatest toxicity observed at the lowest salinity tested. Larval shrimp were significantly more sensitive than adult shrimp to both dispersants, and both life stages were significantly more sensitive to Finasol than to Corexit. Furthermore, significant sublethal effects were seen at higher concentrations of both dispersants compared to the control. These data will enable environmental managers to make informed decisions regarding dispersant use in future oil spills.
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Federal Register 2010, 2011, 2012, 2013, 2014
2011-11-17
... recirculating loop that serves as the ultimate heat sink for PTN Units 3 and 4. The CCS is operated under an...) permit from the FDEP (NPDES permit number FL0001562) for water discharges to an onsite closed-loop..., the CCS water is hyper-saline (twice the salinity of Biscayne Bay) with seasonal variations ranging...
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NASA Astrophysics Data System (ADS)
Kuanui, Pataporn; Chavanich, Suchana; Viyakarn, Voranop; Omori, Makoto; Lin, Chiahsin
2015-06-01
This study investigated the effects of temperature and salinity on growth, survival, and photosynthetic efficiency of three coral species, namely, Pocillopora damicornis, Acropora millepora and Platygyra sinensis of different ages (6 and 18 months old). The experimental corals were cultivated via sexual propagation. Colonies were exposed to 5 different temperatures (18, 23, 28, 33, and 38°C) and 5 different salinities (22, 27, 32, 37, and 42 psu). Results showed that temperature significantly affected photosynthetic efficiency (Fv/Fm) (p < 0.05) compared to salinity. The maximum quantum yield of corals decreased ranging from 5% to 100% when these corals were exposed to different temperatures and salinities. Temperature also significantly affected coral growth and survival. However, corals exposed to changes in salinity showed higher survivorship than those exposed to changes in temperature. Results in this study also showed that corals of different ages and of different species did not display the same physiological responses to changes in environmental conditions. Thus, the ability of corals to tolerate salinity and temperature stresses depends on several factors.
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Environmental Flow for Sungai Johor Estuary
NASA Astrophysics Data System (ADS)
Adilah, A. Kadir; Zulkifli, Yusop; Zainura, Z. Noor; Bakhiah, Baharim N.
2018-03-01
Sungai Johor estuary is a vital water body in the south of Johor and greatly affects the water quality in the Johor Straits. In the development of the hydrodynamic and water quality models for Sungai Johor estuary, the Environmental Fluid Dynamics Code (EFDC) model was selected. In this application, the EFDC hydrodynamic model was configured to simulate time varying surface elevation, velocity, salinity, and water temperature. The EFDC water quality model was configured to simulate dissolved oxygen (DO), dissolved organic carbon (DOC), chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N), nitrate nitrogen (NO3-N), phosphate (PO4), and Chlorophyll a. The hydrodynamic and water quality model calibration was performed utilizing a set of site specific data acquired in January 2008. The simulated water temperature, salinity and DO showed good and fairly good agreement with observations. The calculated correlation coefficients between computed and observed temperature and salinity were lower compared with the water level. Sensitivity analysis was performed on hydrodynamic and water quality models input parameters to quantify their impact on modeling results such as water surface elevation, salinity and dissolved oxygen concentration. It is anticipated and recommended that the development of this model be continued to synthesize additional field data into the modeling process.
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LaPeyre, Megan K.; Geaghan, James; Decossas, Gary A.; La Peyre, Jerome F.
2016-01-01
Freshwater inflow characteristics define estuarine functioning by delivering nutrients, sediments, and freshwater, which affect biological resources and ultimately system production. Using 20 years of water quality, weather, and oyster growth and mortality data from Breton Sound Estuary (BSE), Louisiana, we examined the relationship of riverine, weather, and tidal influence on estuarine salinity, and the relationship of salinity to oyster growth and mortality. Mississippi River discharge was found to be the most important factor determining salinity patterns over oyster grounds within lower portions of BSE, with increased river flow associated with lowered salinities, while easterly winds associated with increased salinity were less influential. These patterns were consistent throughout the year. Salinity and temperature (season) were found to critically control oyster growth and mortality, suggesting that seasonal changes to river discharge affecting water quality over the oyster grounds have profound impacts on oyster populations. The management of oyster reefs in estuaries (such as BSE) requires an understanding of how estuarine hydrodynamics and salinity are influenced by forcing factors such as winds, river flow, and by the volume, timing, and location of controlled releases of riverine water.
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NASA Astrophysics Data System (ADS)
Payo, Andrés.; Lázár, Attila N.; Clarke, Derek; Nicholls, Robert J.; Bricheno, Lucy; Mashfiqus, Salehin; Haque, Anisul
2017-05-01
Understanding the dynamics of salt movement in the soil is a prerequisite for devising appropriate management strategies for land productivity of coastal regions, especially low-lying delta regions, which support many millions of farmers around the world. At present, there are no numerical models able to resolve soil salinity at regional scale and at daily time steps. In this research, we develop a novel holistic approach to simulate soil salinization comprising an emulator-based soil salt and water balance calculated at daily time steps. The method is demonstrated for the agriculture areas of coastal Bangladesh (˜20,000 km2). This shows that we can reproduce the dynamics of soil salinity under multiple land uses, including rice crops, combined shrimp and rice farming, as well as non-rice crops. The model also reproduced well the observed spatial soil salinity for the year 2009. Using this approach, we have projected the soil salinity for three different climate ensembles, including relative sea-level rise for the year 2050. Projected soil salinity changes are significantly smaller than other reported projections. The results suggest that inter-season weather variability is a key driver of salinization of agriculture soils at coastal Bangladesh.
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Espinar, J.L.; Garcia, L.V.; Clemente, L.
2005-01-01
The effect of salinity level and extended exposure to different salinity and flooding conditions on germination patterns of three saltmarsh clonal growth plants (Juncus subulatus, Scirpus litoralis, and S. maritimus) was studied. Seed exposure to extended flooding and saline conditions significantly affected the outcome of the germination process in a different, though predictable, way for each species, after favorable conditions for germination were restored. Tolerance of the germination process was related to the average salinity level measured during the growth/germination season at sites where established individuals of each species dominated the species cover. No relationship was found between salinity tolerance of the germination process and seed response to extended exposure to flooding and salinity conditions. The salinity response was significantly related to the conditions prevailing in the habitats of the respective species during the unfavorable (nongrowth/nongermination) season. Our results indicate that changes in salinity and hydrology while seeds are dormant affect the outcome of the seed-bank response, even when conditions at germination are identical. Because these environmental-history-dependent responses differentially affect seed germination, seedling density, and probably sexual recruitment in the studied and related species, these influences should be considered for wetland restoration and management.
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Hu, Minjie; Ren, Hongchang; Ren, Peng; Li, Jiabing; Wilson, Benjamin J; Tong, Chuan
2017-02-01
Although estuarine tidal marshes are important contributors to the emission of greenhouse gases into the atmosphere, the relationship between carbon dioxide (CO 2 ), methane (CH 4 ) emission, and environmental factors, with respect to estuarine marshes, has not been clarified thoroughly. This study investigated the crucial factors controlling the emission of CO 2 and CH 4 from a freshwater marsh and a brackish marsh located in a subtropical estuary in southeastern China, as well as their magnitude. The duration of the study period was November 2013 to October 2014. Relevant to both the field and incubation experiments, the CO 2 and CH 4 emissions from the two marshes showed pronounced seasonal variations. The CO 2 and CH 4 emissions from both marshes demonstrated significant positive correlations with the air/soil temperature (p<0.01), but negative correlations with the soil electrical conductivity and the pore water/tide water Cl - and SO 4 2- (p<0.01). The results indicate no significant difference in the CO 2 emissions between the freshwater and brackish marshes in the subtropical estuary, whereas there was a difference in the CH 4 emissions between the two sites (p<0.01). Although future sea-level rise and saltwater intrusion could reduce the CH 4 emissions from the estuarine freshwater marshes, these factors had little effect on the CO 2 emissions with respect to an increase in salinity of less than 5‰. The findings of this study could have important implications for estimating the global warming contributions of estuarine marshes along differing salinity gradients. Copyright © 2016. Published by Elsevier B.V.
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Ding, Lanping; Ma, Yuanyuan; Huang, Bingxin; Chen, Shanwen
2013-01-01
This study simulated outdoor environmental living conditions and observed the growth rates and changes of several photosynthetic pigments (Chl a, Car, PE, and PC) in Hypnea cervicornis J. Agardh (Gigartinales, Rhodophyta) by setting up different ranges of salinity (25, 30, 35, 40, 45, and 50) and temperature (15, 20, 25, and 30°C). At conditions of culture, the results are as follows. (1) Changes in salinity and temperature have significant effects on the growth of H. cervicornis. The growth rates first increase then decrease as the temperature increases, while growth tends to decline as salinity increases. The optimum salinity and temperature conditions for growth are 25 and 25°C, respectively. (2) Salinity and temperature have significant or extremely significant effects on photosynthetic pigments (Chl a, Car, PE, and PC) in H. cervicornis. The results of this study are advantageous to ensure propagation and economic development of this species in the southern sea area of China. PMID:24350276
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NASA Astrophysics Data System (ADS)
Little, S.; Wood, P. J.; Elliott, M.
2017-11-01
Coastal and estuarine systems worldwide are under threat from global climate change, with potential consequences including an increase in salinities and incursion of saltwater into areas currently subject to tidal and non-tidal freshwater regimes. It is commonly assumed that climate-driven increases in estuarine salinities and saline incursion will be directly reflected in an upstream shift in species distributions and patterns of community composition based on salinity tolerance. This study examined the responses of benthos to medium-term salinity changes in two macrotidal river-estuary systems in SE England to test whether these responses may be representative of climate-induced salinity changes over the long-term. The study reinforced the effect of salinity, related to tidal incursion, as the primary environmental driver of benthic species distribution and community composition. Salinity, however, acted within a hierarchy of factors followed by substratum type, with biotic competition and predator-prey relationships superimposed on these. The assumption that increasing salinities will be directly reflected in a shift in species distributions and patterns of community composition upstream over the long-term was shown to be over simplistic and not representative of a complex and highly variable system. Relative Sea Level Rise (RSLR) projections were predicted to increase estuarine salinities and saline incursion in the study estuaries, which together with projected reductions in river flow will have important consequences for estuarine structure and function, particularly in tidal limnetic zones, despite estuarine communities being pre-adapted to cope with fluctuating salinities. The study identified, however, that limnic-derived fauna inhabiting these zones may demonstrate greater tolerance to salinity change than is currently recognised, and may persist where salinity increases are gradual and zones unbounded.
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López-Hoffman, Laura; Anten, Niels P R; Martínez-Ramos, Miguel; Ackerly, David D
2007-01-01
We have studied the interactive effects of salinity and light on Avicennia germinans mangrove seedlings in greenhouse and field experiments. We hypothesized that net photosynthesis, growth, and survivorship rates should increase more with an increase in light availability for plants growing at low salinity than for those growing at high salinity. This hypothesis was supported by our results for net photosynthesis and growth. Net daily photosynthesis did increase more with increasing light for low-salinity plants than for high-salinity plants. Stomatal conductance, leaf-level transpiration, and internal CO(2) concentrations were lower at high than at low salinity. At high light, the ratio of leaf respiration to assimilation was 2.5 times greater at high than at low salinity. Stomatal limitations and increased respiratory costs may explain why, at high salinity, seedlings did not respond to increased light availability with increased net photosynthesis. Seedling mass and growth rates increased more with increasing light availability at low than at high salinity. Ratios of root mass to leaf mass were higher at high salinity, suggesting that either water or nutrient limitations may have limited seedling growth at high salinity in response to increasing light. The interactive effects of salinity and light on seedling size and growth rates observed in the greenhouse were robust in the field, despite the presence of other factors in the field--such as inundation, nutrient gradients, and herbivory. In the field, seedling survivorship was higher at low than at high salinity and increased with light availability. Interestingly, the positive effect of light on seedling survivorship was stronger at high salinity, indicating that growth and survivorship rates are decoupled. In general, this study demonstrates that environmental effects at the leaf-level also influence whole plant growth in mangroves.
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Modelling the salinization of a coastal lagoon-aquifer system
NASA Astrophysics Data System (ADS)
Colombani, N.; Mastrocicco, M.
2017-08-01
In this study, a coastal area constituted by alternations of saline-brackish lagoons and freshwater bodies was studied and modelled to understand the hydrological processes occurring between the lagoons, the groundwater system of the Po River Delta (Italy) and the Adriatic Sea. The contribution of both evaporation and anthropogenic factors on groundwater salinization was assessed by means of soil, groundwater and surface water monitoring. Highresolution multi-level samplers were used to capture salinity gradients within the aquifer and surface water bodies. Data were employed to calibrate a density-dependent numerical transport model implemented with SEAWAT code along a transect perpendicular to the coast line. The results show that the lagoon is hydraulically well connected with the aquifer, which provides the major source of salinity because of the upcoming of paleo-seawater from the aquitard laying at the base of the unconfined aquifer. On the contrary, the seawater (diluted by the freshwater river outflow) creates only a limited saltwater wedge. The increase in groundwater salinity could be of serious concern, especially for the pinewood located in the dune near the coast, sensitive to salinity increases. This case study represents an interesting paradigm for other similar environmental setting, where the assumption of classical aquifer salinization from a saltwater wedge intruding from the sea is often not representative of the actual aquifer’s salinization mechanisms.
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Yang, Hao; Meng, Yang; Song, Youxin; Tan, Yalin; Warren, Alan; Li, Jiqiu; Lin, Xiaofeng
2017-07-01
Although salinity fluctuation is a prominent characteristic of many coastal ecosystems, its effects on biological adaptation have not yet been fully recognized. To test the salinity fluctuations on biological adaptation, population growth dynamics and Na + /K + -ATPase activity were investigated in the euryhaline bacterium Idiomarina sp. DYB, which was acclimated at different salinity exposure levels, exposure times, and shifts in direction of salinity. Results showed: (1) bacterial population growth dynamics and Na + /K + -ATPase activity changed significantly in response to salinity fluctuation; (2) patterns of variation in bacterial growth dynamics were related to exposure times, levels of salinity, and shifts in direction of salinity change; (3) significant tradeoffs were detected between growth rate (r) and carrying capacity (K) on the one hand, and Na + /K + -ATPase activity on the other; and (4) beneficial acclimation was confirmed in Idiomarina sp. DYB. In brief, this study demonstrated that salinity fluctuation can change the population growth dynamics, Na + /K + -ATPase activity, and tradeoffs between r, K, and Na + /K + -ATPase activity, thus facilitating bacterial adaption in a changing environment. These findings provide constructive information for determining biological response patterns to environmental change. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Electrical Impedance Tomography of Electrolysis
Meir, Arie; Rubinsky, Boris
2015-01-01
The primary goal of this study is to explore the hypothesis that changes in pH during electrolysis can be detected with Electrical Impedance Tomography (EIT). The study has relevance to real time control of minimally invasive surgery with electrolytic ablation. To investigate the hypothesis, we compare EIT reconstructed images to optical images acquired using pH-sensitive dyes embedded in a physiological saline agar gel phantom treated with electrolysis. We further demonstrate the biological relevance of our work using a bacterial E.Coli model, grown on the phantom. The results demonstrate the ability of EIT to image pH changes in a physiological saline phantom and show that these changes correlate with cell death in the E.coli model. The results are promising, and invite further experimental explorations. PMID:26039686
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Abid, Aamir; Kennedy, Ian M.; Kültz, Dietmar
2014-01-01
The increasing use of manufactured nanoparticles (NP) in different applications has triggered the need to understand their putative ecotoxicological effects in the environment. Copper oxide nanoparticles (CuO NP) are toxic, and induce oxidative stress and other pathophysiological conditions. The unique properties of NP can change depending on the characteristics of the media they are suspended in, altering the impact on their toxicity to aquatic organisms in different environments. Here, Mozambique tilapia (O. mossambicus) were exposed to flame synthesized CuO NP (0.5 and 5 mg·L−1) in two environmental contexts: (a) constant freshwater (FW) and (b) stepwise increase in environmental salinity (SW). Sublethal effects of CuO NP were monitored and used to dermine exposure endpoints. Fish exposed to 5 mg·L−1 CuO in SW showed an opercular ventilation rate increase, whereas fish exposed to 5 mg·L−1 in FW showed a milder response. Different effects of CuO NP on antioxidant enzyme activities, accumulation of transcripts for metal-responsive genes, GSH∶GSSG ratio, and Cu content in fish gill and liver also demonstrate that additive osmotic stress modulates CuO NP toxicity. We conclude that the toxicity of CuO NP depends on the particular environmental context and that salinity is an important factor for modulating NP toxicity in fish. PMID:24520417
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Influence of Environmental Variables on Gambierdiscus spp. (Dinophyceae) Growth and Distribution
Xu, Yixiao; Richlen, Mindy L.; Liefer, Justin D.; Robertson, Alison; Kulis, David; Smith, Tyler B.; Parsons, Michael L.; Anderson, Donald M.
2016-01-01
Benthic dinoflagellates in the genus Gambierdiscus produce the ciguatoxin precursors responsible for the occurrence of ciguatera toxicity. The prevalence of ciguatera toxins in fish has been linked to the presence and distribution of toxin-producing species in coral reef ecosystems, which is largely determined by the presence of suitable benthic habitat and environmental conditions favorable for growth. Here using single factor experiments, we examined the effects of salinity, irradiance, and temperature on growth of 17 strains of Gambierdiscus representing eight species/phylotypes (G. belizeanus, G. caribaeus, G. carolinianus, G. carpenteri, G. pacificus, G. silvae, Gambierdiscus sp. type 4–5), most of which were established from either Marakei Island, Republic of Kiribati, or St. Thomas, United States Virgin Island (USVI). Comparable to prior studies, growth rates fell within the range of 0–0.48 divisions day-1. In the salinity and temperature studies, Gambierdiscus responded in a near Gaussian, non-linear manner typical for such studies, with optimal and suboptimal growth occurring in the range of salinities of 25 and 45 and 21.0 and 32.5°C. In the irradiance experiment, no mortality was observed; however, growth rates at 55μmol photons · m-2 · s-1 were lower than those at 110–400μmol photons · m-2 · s-1. At the extremes of the environmental conditions tested, growth rates were highly variable, evidenced by large coefficients of variability. However, significant differences in intraspecific growth rates were typically found only at optimal or near-optimal growth conditions. Polynomial regression analyses showed that maximum growth occurred at salinity and temperature levels of 30.1–38.5 and 23.8–29.2°C, respectively. Gambierdiscus growth patterns varied among species, and within individual species: G. belizeanus, G. caribaeus, G. carpenteri, and G. pacificus generally exhibited a wider range of tolerance to environmental conditions, which may explain their broad geographic distribution. In contrast, G. silvae and Gambierdiscus sp. types 4–5 all displayed a comparatively narrow range of tolerance to temperature, salinity, and irradiance. PMID:27074134
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Hu, Dongxu; Pan, Luqing; Zhao, Qun; Ren, Qin
2015-12-01
The Pacific white shrimp, Litopenaeus vannamei (L. vannamei), is one of the most farmed species. Salinity is an important environmental factor that affects its growth and distribution. However, the molecular mechanism of the shrimp in response to salinity stress remains largely unclear. High-throughput sequencing is a helpful tool to analyze the molecular response to salinity challenge in shrimp. In the present study, the transcriptomic responses of the gills in L. vannamei under low salinity stress were detected by Illumina's digital gene expression system. A total of 10,725,789 and 10,827,411 reads were generated from the non-changed and low salinity changed groups, respectively. 64,590 Unigenes with an average length of 764 bp were generated. Compared with the control, 585 genes were differentially expressed under low salinity. GO functional analysis and KEGG pathway analysis indicated some vital genes in response to the challenge. Ten genes related to osmoregulation and ambient salinity adaption were selected to validate the DGE results by RT-qPCR. This work provides valuable information to study the mechanism of salinity adaption in L. vannamei. Genes and pathways from the results will be beneficial to reveal the molecular basis of osmoregulation. It also gives an insight into the response to the salinity challenge in L. vannamei. Copyright © 2015 Elsevier B.V. All rights reserved.
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Courtney, Abigail J; Xu, Jichen; Xu, Yan
2016-02-01
Salinity is a major environmental factor limiting the productivity and quality of crop plants. While most cereal crops are salt-sensitive, several halophytic grasses are able to maintain their growth under saline conditions. Elucidating the mechanisms for salinity responses in halophytic grasses would contribute to the breeding of salt-tolerant cereal and turf species belonging to the Poaceae family. Smooth cordgrass (Spartina alterniflora) is a dominant native halophytic grass in the Hackensack Meadowlands, the coastal salt marshes located in northeastern New Jersey. The goals of this study were to examine the growth pattern of S. alterniflora in a salinity gradient and identify an optimal range of salinity for its maximal growth. The regulation of its antioxidant system and gene expression under supraoptimal salinity conditions was also investigated. Our results showed that a salinity of 4 parts per thousand (ppt) (68 mM) was most favorable for the growth of S. alterniflora, followed by a non-salt environment. S. alterniflora responded to salts in the environment by regulating antioxidant enzyme activities and the expression of stress-induced proteins such as ALDH, HVA22 and PEPC. The plant may tolerate salinity up to the concentration of sea water, but any salinity above 12 ppt retarded its growth and altered the expression of genes encoding critical proteins. Copyright © 2015 Elsevier Masson SAS. All rights reserved.
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NASA Astrophysics Data System (ADS)
Baustian, M. M.; Stagg, C. L.; Perry, C. L.; Moss, L.; Carruthers, T.; Allison, M. A.
2017-12-01
The vegetation community and environmental characteristics of marsh habitats influence how carbon is produced, decomposed, and accumulated. In coastal Louisiana, marsh habitats have historically been classified as fresh, intermediate, brackish, and saline based on their position along the salinity gradient. Changing environmental conditions, such as sea-level rise and coastal restoration activities, may change the relative extent of the four marsh habitats and how soil carbon is accumulated in the short and long term. Soil cores (100 cm) were collected at each of 24 sites within the four marsh habitats in two coastal Louisiana basins, Terrebonne and Barataria. Each core was sectioned into 2-cm depth intervals and analyzed for bulk density, organic matter, and radionuclide geochronology (137Cs and 210Pb). Feldspar marker horizon data was utilized to estimate short-term accretion rates. Short-term total carbon accumulation rates (using the top 10 cm soil properties and feldspar horizon markers) among marsh type categories were not significantly different (mean ± std. err of 190 ± 27 g TC m-2 yr-1, n = 15). However, regression analysis, on measured salinity at individual sites, indicated that mean annual salinity had a significant negative relationship suggesting that more saline marshes may be accumulating less carbon in the short term. Coastal Louisiana marsh area (1,433,700 ha) soils store in the short term about 2.7 to 3.3 Tg C yr-1. Long-term carbon accumulation rates of classified marsh type categories also did not differ (mean ± std. err of 80.0 ±8.9 g TC m-2 yr-1, n = 16) and were over two times lower than short-term accumulation rates. Coast-wide, in Louisiana, these soils bury approximately 1.2 Tg TC yr-1 in the long term and contribute about 1-5% of the global marsh/mangrove carbon sink budget. Carbon accumulation and storage rates tend to decrease over long time periods and estimating these rates from varying soil core depths (10 vs. 100 cm) has important implications to estimating carbon budgets and comparing rates in the literature. This study helps to characterize short and long-term carbon accumulation rates in four marsh salinity types and provides insight into how carbon accumulation may change with predicted changes in marsh type resulting from environmental change.
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Numerical Simulation of Borehole Flow in Deep Monitor Wells, Pearl Harbor Aquifer, Oahu, Hawaii
NASA Astrophysics Data System (ADS)
Rotzoll, K.; Oki, D. S.; El-Kadi, A. I.
2010-12-01
Salinity profiles collected from uncased deep monitor wells are commonly used to monitor freshwater-lens thickness in coastal aquifers. However, vertical flow in these wells can cause the measured salinity to differ from salinity in the adjacent aquifer. Substantial borehole flow has been observed in uncased wells in the Pearl Harbor aquifer, Oahu, Hawaii. A numerical modeling approach, incorporating aquifer hydraulic characteristics and recharge rates representative of the Pearl Harbor aquifer, was used to evaluate the effects of borehole flow on measured salinity profiles from deep monitor wells. Borehole flow caused by vertical hydraulic gradients associated with the natural regional groundwater-flow system and local groundwater withdrawals was simulated. Model results were used to estimate differences between vertical salinity profiles in deep monitor wells and the adjacent aquifer in areas of downward, horizontal, and upward flow within the regional flow system—for cases with and without nearby pumped wells. Aquifer heterogeneity, represented in the model as layers of contrasting permeability, was incorporated in model scenarios. Results from this study provide insight into the magnitude of the differences between vertical salinity profiles from deep monitor wells and the salinity distributions in the aquifers. These insights are relevant and are critically needed for management and predictive modeling purposes.
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NASA Astrophysics Data System (ADS)
Jaureguizar, Andrés Javier; Cortés, Federico; Milessi, Andrés Conrado; Cozzolino, Ezequiel; Allega, Lucrecia
2015-12-01
To improve the understanding of the environmental processes affecting small-scale gillnet fisheries along neighboring waters of estuaries, we analyzed the main climatic forcing and the environmental conditions, the fishery landing spatial and temporal variation, including the relative importance of site, distance to coast, temperature and salinity in the structuring of landed species profile. Data were collected monthly in two sites along the adjacent south coast of the Río de la Plata between October 2009 and September 2010. The gillnet fishery was dominated by four species (Cynoscion guatucupa, Micropogonias furnieri, Mustelus schmitti and Parona signata) from a total of 38 species landed, which accounted for 98.6% of total landings. The fishing effort and landings by the fishery were largely conditioned by the availability of fish species in the fishing grounds resulting from the combination of the species reproductive behavior and the predominant environmental conditions. The highest abundances for some species occurred before (M. furnieri, C. guatucupa, P. signata) or during the reproductive period (M. schmitti, Squatina guggenheim), while in other species it was associated with favorable environmental conditions during cold months (Squalus acanthias, Callorhinchus callorhynchus, Galeorhinus galeus) or warm months (Trichiurus lepturus). The predominant seasonal environmental conditions along the coast were mainly determined by the location of Río de la Plata boundary, whose spatial extent was forced by the wind patterns and freshwater discharge. The strong environmental dependence means that the small-scale fishery is in fact a seasonal trans-ecosystem fishery. This attribute, together that shared the resources with the industrial fishery and the overlap of the fishery ground with essential habitat of sharks, make this kind of small-scale gillnet fishery particularly relevant to be included in the development of a coastal ecosystem-based management approach.
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NASA Astrophysics Data System (ADS)
Ren, D.; Huang, G., Sr.; Xu, X.; Huang, Q., Sr.; Xiong, Y.
2016-12-01
Soil salinity analysis on a regional scale is of great significance for protecting agriculture production and maintaining eco-environmental health in arid and semi-arid irrigated areas. In this study, the Hetao Irrigation District (Hetao) in Inner Mongolia Autonomous Region, with suffering long-term soil salinization problems, was selected as the case study area. Field sampling experiments and investigations related to soil salt contents, crop growth and yields were carried out across the whole area, during April to August in 2015. Soil salinity characteristics in space and time were systematically analyzed for Hetao as well as the corresponding impacts on crops. Remotely sensed map of soil salinity distribution for surface soil was also derived based on the Landsat OLI data with a 30 m resolution. The results elaborated the temporal and spatial dynamics of soil salinity and the relationships with irrigation, groundwater depth and crop water consumption in Hetao. In addition, the strong spatial variability of salinization was clearly presented by the remotely sensed map of soil salinity. Further, the relationship between soil salinity and crop growth was analyzed, and then the impact degrees of soil salinization on cropping pattern, leaf area index, plant height and crop yield were preliminarily revealed. Overall, this study can provide very useful information for salinization control and guide the future agricultural production and soil-water management for the arid irrigation districts analogous to Hetao.
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Salinity stress response in estuarine fishes from the Murray Estuary and Coorong, South Australia.
Hossain, Md Afzal; Aktar, Shefali; Qin, Jian G
2016-12-01
Estuaries are unstable ecosystems and can be changed by the environmental and anthropogenic impact. The Murray Estuary and Coorong were degraded by drought and low freshwater input in the last decade and therefore transformed into the largest hyper-saline lagoon in Australia. This study evaluates the physiological stress of two estuarine fish species (small-mouthed hardyhead Atherinosoma microstoma and Tamar goby Afurcagobius tamarensis) to the induced salinity change in captivity. The test fishes were collected from the Coorong and transported to the laboratory in the water from the Coorong. Each fish species was exposed to different levels of salinity, and a number of enzymes were assessed to measure the stress response of fish to salinity change. The activity of reactive oxygen species was significantly increased with the salinity change in both fish species compared with the fish in the control. Significant salinity effect on superoxide dismutase activity was observed on Tamar goby but not on small-mouthed hardyhead. Conversely, the impact of salinity on catalase activity was detected on small-mouthed hardyhead but not on Tamar goby. The study reveals that the induction of physical stress by salinity changes occurred in both Tamar goby and small-mouthed hardyhead despite the varying response of antioxidant enzymes between fish species. The study provides an insight into the understanding of physiological adaptation in estuarine fish to salinity change. The results could improve our knowledge on stress response and resilience of estuarine fish to hypo- and hyper-salinity stress.
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Towards a theory of ecotone resilience: coastal vegetation on a salinity gradient.
Jiang, Jiang; Gao, Daozhou; DeAngelis, Donald L
2012-08-01
Ecotones represent locations where vegetation change is likely to occur as a result of climate and other environmental changes. Using a model of an ecotone vulnerable to such future changes, we estimated the resilience of the ecotone to disturbances. The specific ecotone is that between two different vegetation types, salinity-tolerant and salinity-intolerant, along a gradient in groundwater salinity. In the case studied, each vegetation type, through soil feedback loops, promoted local soil salinity levels that favor itself in competition with the other type. Bifurcation analysis was used to study the system of equations for the two vegetation types and soil salinity. Alternative stable equilibria, one for salinity-tolerant and one for salinity intolerant vegetation, were shown to exist over a region of the groundwater salinity gradient, bounded by two bifurcation points. This region was shown to depend sensitively on parameters such as the rate of upward infiltration of salinity from groundwater into the soil due to evaporation. We showed also that increasing diffusion rates of vegetation can lead to shrinkage of the range between the two bifurcation points. Sharp ecotones are typical of salt-tolerant vegetation (mangroves) near the coastline and salt-intolerant vegetation inland, even though the underlying elevation and groundwater salinity change very gradually. A disturbance such as an input of salinity to the soil from a storm surge could upset this stable boundary, leading to a regime shift of salinity-tolerant vegetation inland. We showed, however, that, for our model as least, a simple pulse disturbance would not be sufficient; the salinity would have to be held at a high level, as a 'press', for some time. The approach used here should be generalizable to study the resilience of a variety of ecotones to disturbances. Published by Elsevier Inc.
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Towards a theory of ecotone resilience: coastal vegetation on a salinity gradient
Jiang, Jiang; Gao, Daozhou; DeAngelis, Donald L.
2012-01-01
Ecotones represent locations where vegetation change is likely to occur as a result of climate and other environmental changes. Using a model of an ecotone vulnerable to such future changes, we estimated the resilience of the ecotone to disturbances. The specific ecotone is that between two different vegetation types, salinity-tolerant and salinity-intolerant, along a gradient in groundwater salinity. In the case studied, each vegetation type, through soil feedback loops, promoted local soil salinity levels that favor itself in competition with the other type. Bifurcation analysis was used to study the system of equations for the two vegetation types and soil salinity. Alternative stable equilibria, one for salinity-tolerant and one for salinity intolerant vegetation, were shown to exist over a region of the groundwater salinity gradient, bounded by two bifurcation points. This region was shown to depend sensitively on parameters such as the rate of upward infiltration of salinity from groundwater into the soil due to evaporation. We showed also that increasing diffusion rates of vegetation can lead to shrinkage of the range between the two bifurcation points. Sharp ecotones are typical of salt-tolerant vegetation (mangroves) near the coastline and salt-intolerant vegetation inland, even though the underlying elevation and groundwater salinity change very gradually. A disturbance such as an input of salinity to the soil from a storm surge could upset this stable boundary, leading to a regime shift of salinity-tolerant vegetation inland. We showed, however, that, for our model as least, a simple pulse disturbance would not be sufficient; the salinity would have to be held at a high level, as a 'press', for some time. The approach used here should be generalizable to study the resilience of a variety of ecotones to disturbances.
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Quantifying salinity and season effects on eastern oyster clearance and oxygen consumption rates
Casas, S.M.; Lavaud, Romain; LaPeyre, Megan K.; Comeau, L. A.; Filgueira, R.; LaPeyre, Jerome F.
2018-01-01
There are few data on Crassostrea virginica physiological rates across the range of salinities and temperatures to which they are regularly exposed, and this limits the applicability of growth and production models using these data. The objectives of this study were to quantify, in winter (17 °C) and summer (27 °C), the clearance and oxygen consumption rates of C. virginica from Louisiana across a range of salinities typical of the region (3, 6, 9, 15 and 25). Salinity and season (temperature and reproduction) affected C. virginica physiology differently; salinity impacted clearance rates with reduced feeding rates at low salinities, while season had a strong effect on respiration rates. Highest clearance rates were found at salinities of 9–25, with reductions ranging from 50 to 80 and 90 to 95% at salinities of 6 and 3, respectively. Oxygen consumption rates in summer were four times higher than in winter. Oxygen consumption rates were within a narrow range and similar among salinities in winter, but varied greatly among individuals and salinities in summer. This likely reflected varying stages of gonad development. Valve movements measured at the five salinities indicated oysters were open 50–60% of the time in the 6–25 salinity range and ~ 30% at a salinity of 3. Reduced opening periods, concomitant with narrower valve gap amplitudes, are in accord with the limited feeding at the lowest salinity (3). These data indicate the need for increased focus on experimental determination of optimal ranges and thresholds to better quantify oyster population responses to environmental changes.
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Kantún-Manzano, C A; Herrera-Silveira, J A; Arcega-Cabrera, F
2018-01-01
The influence of coastal submarine groundwater discharges (SGD) on the distribution and abundance of seagrass meadows was investigated. In 2012, hydrological variability, nutrient variability in sediments and the biotic characteristics of two seagrass beds, one with SGD present and one without, were studied. Findings showed that SGD inputs were related with one dominant seagrass species. To further understand this, a generalized additive model (GAM) was used to explore the relationship between seagrass biomass and environment conditions (water and sediment variables). Salinity range (21-35.5 PSU) was the most influential variable (85%), explaining why H. wrightii was the sole plant species present at the SGD site. At the site without SGD, GAM could not be performed since environmental variables could not explain a total variance of > 60%. This research shows the relevance of monitoring SGD inputs in coastal karstic areas since they significantly affect biotic characteristics of seagrass beds.
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Rim of the Pacific (RIMPAC). Programmatic Environmental Assessment
2002-06-01
ma’oloa) E Portulaca sclerocarpa Hard-fruit purslane (‘Ihi) E Portulaca villosa Hairy purslane SOC Silene hawaiiensis Hawaiian catchfly T Silene...not frequent brackish water and are not generally present in saline habitats. The Hawaiian moorhen generally nests in areas of standing freshwater...reservoirs, brackish wetlands, or rarely saline water. Coots nest in open fresh and brackish ponds, irrigation ditches, on shallow reservoirs, and small
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Environmental Quality Research Fish and Aufwuchs Bioassay
1981-01-01
reproductive success at WSF of shale JP-8 concentrations of 0. 51 ± 0. 30 mg/V. Results of continuous-flow bioassays of the WSF of hydrocarbon fuels to...42 Reproduction .................... ....................... 42 SALINE WATER BIOASSAYS OF HYDROCARBON FUELS ...... . . 47...and development and reproductive ability. Studies on JP-4, JP-8, and shale JP-8 have been conducted in saline water from San Francisco Bay at the
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Metagenomic covariation along densely sampled environmental gradients in the Red Sea
Thompson, Luke R; Williams, Gareth J; Haroon, Mohamed F; Shibl, Ahmed; Larsen, Peter; Shorenstein, Joshua; Knight, Rob; Stingl, Ulrich
2017-01-01
Oceanic microbial diversity covaries with physicochemical parameters. Temperature, for example, explains approximately half of global variation in surface taxonomic abundance. It is unknown, however, whether covariation patterns hold over narrower parameter gradients and spatial scales, and extending to mesopelagic depths. We collected and sequenced 45 epipelagic and mesopelagic microbial metagenomes on a meridional transect through the eastern Red Sea. We asked which environmental parameters explain the most variation in relative abundances of taxonomic groups, gene ortholog groups, and pathways—at a spatial scale of <2000 km, along narrow but well-defined latitudinal and depth-dependent gradients. We also asked how microbes are adapted to gradients and extremes in irradiance, temperature, salinity, and nutrients, examining the responses of individual gene ortholog groups to these parameters. Functional and taxonomic metrics were equally well explained (75–79%) by environmental parameters. However, only functional and not taxonomic covariation patterns were conserved when comparing with an intruding water mass with different physicochemical properties. Temperature explained the most variation in each metric, followed by nitrate, chlorophyll, phosphate, and salinity. That nitrate explained more variation than phosphate suggested nitrogen limitation, consistent with low surface N:P ratios. Covariation of gene ortholog groups with environmental parameters revealed patterns of functional adaptation to the challenging Red Sea environment: high irradiance, temperature, salinity, and low nutrients. Nutrient-acquisition gene ortholog groups were anti-correlated with concentrations of their respective nutrient species, recapturing trends previously observed across much larger distances and environmental gradients. This dataset of metagenomic covariation along densely sampled environmental gradients includes online data exploration supplements, serving as a community resource for marine microbial ecology. PMID:27420030
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Environmental determinants of Vibrio parahaemolyticus in the Chesapeake Bay.
Davis, Benjamin J K; Jacobs, John M; Davis, Meghan F; Schwab, Kellogg J; DePaola, Angelo; Curriero, Frank C
2017-08-25
Vibrio parahaemolyticus naturally-occurs in brackish and marine waters and is one of the leading causes of seafood-borne illness. Previous work studying the ecology of V. parahaemolyticus is often limited in geographic extent and lacking a full range of environmental measures. This study used a unique, large dataset of surface water samples in the Chesapeake Bay ( n =1,385) collected from 148 monitoring stations from 2007 to 2010. Water was analyzed for over 20 environmental parameters with additional meteorological and surrounding land use data. V. parahaemolyticus -specific genetic markers thermolabile hemolysin ( tlh ), thermostable direct hemolysin ( tdh ), and tdh -related hemolysin ( trh ) were assayed using quantitative PCR (qPCR), and interval-censored regression models with non-linear effects were estimated to account for limits of detection and quantitation. tlh was detected in 19.6% of water samples; tdh or trh markers were not detected. Results confirmed previously reported positive associations for V. parahaemolyticus abundance with temperature and turbidity and negative associations with high salinity (> 10-23‰). Furthermore, the salinity relationship was determined to be a function of both low temperature and turbidity, with an increase of either nullifying the high salinity effect. Associations with dissolved oxygen and phosphate also appeared stronger when samples were taken nearby human developments. Renewed focus on the V. parahaemolyticus ecological paradigm is warranted to protect public health. Importance Vibrio parahaemolyticus is one of the leading causes of seafood-borne illness in the United States and across the globe. Exposure is often through consuming raw or undercooked shellfish. Given the natural presence of the bacterium in the marine environment, improved understanding of its environmental determinants is necessary for future preventative measures. This analysis of environmental Vibrio parahaemolyticus is one of only a few that utilize a large dataset measured over a wide geographic and temporal range. The analysis also includes a large number of environmental parameters for Vibrio modeling, many of which have previously only been tested sporadically, and some of which have not been considered before. The results of the analysis revealed previously unknown relationships between salinity, turbidity, and temperature that provide significant insight into the abundance and persistence of V. parahaemolyticus bacterium in the environment. This information will be essential for developing environmental forecast models for the bacterium. Copyright © 2017 American Society for Microbiology.
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NASA Astrophysics Data System (ADS)
Wagner, F.; Ludwig, R. R.; Noell, U.; Hoang, H. V.; Pham, N. Q.; Larsen, F.; Lindenmaier, F.
2012-04-01
In the Southern Red River Delta (Nam Dinh Province, Vietnam), a local lens of low saline pore water of high quality has been identified in unconsolidated Pleistocene and Neogene aquifers, which are regionally known to contain brackish and saline pore waters. Since the 1990ies, ongoing overexploitation of the fresh groundwater results in decreasing GW heads up to 0.6 m/a and the development of a regional abstraction cone. The presented study focuses on distribution and genesis of fresh and saline pore waters and reflects the results in frame of the regional hydrogeological context. Observations of the geological structure and groundwater dynamics combined with hydrochemical and isotopic studies suggest adjacent Triassic hard rock aquifers as the major source for fresh Pleistocene and Neogene groundwater. Salinization status in the economically most relevant Pleistocene aquifer has been studied based on archive and new hydrochemical and geophysical data. Own hydrochemical field studies as well as laboratory measurements of the specific resistivity of dry sediment samples allow the translation of induction logging data from existing monitoring wells into vertical pore water salinity profiles. This approach suggests the regional occurrence of saline pore water in shallow Holocene sediments in the working area, as confirmed by pore water studies in Hoan et al. (2010). Interpretation of induction logging and stable isotope data suggest vertical diffusion of saline pore water in shallow Holocene sediments as a source for high saline pore water in deeper aquifers. Analytical diffusion modeling for a period of 3000 years confirms that vertical diffusion of Holocene paleo-sea water can explain saline pore water in Pleistocene and Neogene aquifers in a stagnant environment. The constant influx of fresh groundwater from adjacent Triassic hard rocks results in flushing of the primary Pleistocene and Neogene pore water and inhibits the infiltration of saline water from marine Holocene sediments. Consequently, 14C groundwater age dating suggests increasing groundwater ages from fresh to saline pore water in Pleistocene and Neogene up to 14 ka, presuming that contamination with dead carbon is neglectable. Highest 14C ages of low saline water has been observed in the center of the exploited fresh water lens reaching up to 10 ka, reflecting low groundwater flux and recharge rates. Due to the overexploitation, the natural coastward directed groundwater flow has turned towards the centre of the abstraction cone with horizontal apparent velocities of up to 0.6 m/a. This suggests, that brackish and higher saline groundwater from the Red River area (East Nam Dinh) and offshore migrates towards the fresh water lens. Thus, more sustainable exploitation strategies urgently must be implemented to reduce overexploitation of limited and valuable fresh groundwater resources in Nam Dinh Province. Reference: Hoan H., Pham Q. N., Larsen F. Tran L. V., Wagner F., Christiansen A.V. (2010): Processes Controlling High Saline Groundwater in the Nam Dinh Province, Vietnam. 2nd Asia-Pacific Coastal Aquifer Management Meeting (ACAMM), October 18-21, 2011, Jeju Island, Korea.
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Rodrigues, Aurélie P; Santos, Lúcia H M L M; Oliva-Teles, Maria Teresa; Delerue-Matos, Cristina; Guimarães, Laura
2014-11-01
Concurrent exposure of estuarine organisms to man-made and natural stressors has become a common occurrence. Numerous interactions of multiple stressors causing synergistic or antagonistic effects have been described. However, limited information is available on combined effects of emerging pharmaceuticals and natural stressors. This study investigated the joint effects of the antidepressant sertraline and salinity on Carcinus maenas. To improve knowledge about interactive effects and potential vulnerability, experiments were performed with organisms from two estuaries with differing histories of exposure to environmental contamination. Biomarkers related to mode of action of sertraline were employed to assess effects of environmentally realistic concentrations of sertraline at two salinity levels. Synergism and antagonism were identified for biomarkers of cholinergic neurotransmission, energy production, anti-oxidant defences and oxidative damage. Different interactions were found for the two study sites highlighting the need to account for differences in tolerance of local ecological receptors in risk evaluations. Copyright © 2014 Elsevier B.V. All rights reserved.
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Germination of Spores of Astrobiologically Relevant Bacillus Species in High-Salinity Environments.
Nagler, Katja; Julius, Christina; Moeller, Ralf
2016-07-01
In times of increasing space exploration and search for extraterrestrial life, new questions and challenges for planetary protection, aiming to avoid forward contamination of different planets or moons with terrestrial life, are emerging. Spore-forming bacteria such as Bacillus species have a high contamination potential due to their spores' extreme resistance, enabling them to withstand space conditions. Spores require liquid water for their conversion into a growing cell (i.e., spore germination and subsequent growth). If present, water on extraterrestrial planets or moons is likely to be closely associated with salts (e.g., in salty oceans or brines), thus constituting high-salinity environments. Spores of Bacillus subtilis can germinate despite very high salt concentrations, although salt stress does exert negative effects on this process. In this study, germination and metabolic reactivation ("outgrowth") of spores of five astrobiologically relevant Bacillus species (B. megaterium, B. pumilus SAFR-032, B. nealsonii, B. mojavensis, and B. vallismortis) in high salinity (≤3.6 M NaCl) were investigated. Spores of different species exhibited different germination and outgrowth capabilities in high salinity, which strongly depended on germination conditions, especially the exact composition of the medium. In this context, a new "universal" germination trigger for Bacillus spores, named KAGE (KCl, L-alanine, D-glucose, ectoine), was identified, which will be very useful for future comparative germination and outgrowth studies on different Bacillus species. Overall, this study yielded interesting new insights on salt stress effects on spore germination and points out the difficulty of predicting the potential of spores to contaminate salty environments on extraterrestrial celestial bodies. Bacillus species-Spores-Germination-High salinity-Salt stress-NaCl-Inhibition. Astrobiology 16, 500-512.
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Gong, Lu; Zhu, Mei-ling; Liu, Zeng-yuan; Zhang, Xue-ni; Xie, Li-na
2016-04-15
We analyzed the differentiation among the environmental factors and soil organic/inorganic carbon contents of irrigated desert soil, brown desert soil, saline soil and aeolian sandy soil by classical statistics methods, and studied the correlation between soil carbon contents and the environmental factor by redundancy analysis (RDA) in a typical oasis of Yutian in the southern edge of the Tarim Basin. The results showed that the average contents of soil organic carbon and soil inorganic carbon were 2.51 g · kg⁻¹ and 25.63 g · kg⁻¹ respectively. The soil organic carbon content of the irrigated desert soil was significantly higher than those of brown desert soil, saline soil and aeolian sandy soil, while the inorganic carbon content of aeolian sandy soil was significantly higher than those of other soil types. The soil moisture and nutrient content were the highest in the irrigated desert soil and the lowest in the aeolian sandy sail. All soil types had high degree of salinization except the irrigated desert soil. The RDA results showed that the impacts of environmental factors on soil carbon contents ranked in order of importance were total nitrogen > available phosphorus > soil moisture > ground water depth > available potassium > pH > total salt. The soil carbon contents correlated extremely significantly with total nitrogen, available phosphorus, soil moisture and ground water depth (P < 0.01), and it correlated significantly with available potassium and pH (P < 0.05). There was no significant correlation between soil carbon contents and other environmental factors (P > 0.05).
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Cover of coastal vegetation as an indicator of eutrophication along environmental gradients.
Wikström, Sofia A; Carstensen, Jacob; Blomqvist, Mats; Krause-Jensen, Dorte
2016-01-01
Coastal vegetation communities are important for primary production, biodiversity, coastal protection, carbon and nutrient cycling which, in combination with their sensitivity to eutrophication, render them potential indicators of environmental status for environmental policies like the EU Water and Marine Strategy Framework Directives. We evaluated one potential indicator for coastal vegetation, the cumulative cover at depths where the vegetation is light limited, by investigating its response to eutrophication along gradients in natural conditions. We used a large data set covering the Swedish coastline, spanning broad gradients in nutrient level, water clarity, seabed substrate, physical exposure and climate in addition to a salinity gradient from 0.5 to 30.5. Macroalgal cover increased significantly along gradients of declining nutrient concentration and increasing water clarity when we had accounted for diver effects, spatio-temporal sampling variability, salinity gradients, wave exposure and latitude. The developed empirical model explained 79% of the variation in algal cover across 130 areas. Based on this, we identified macroalgal cover as a promising indicator across the Baltic Sea, Kattegat and Skagerrak. A parallel analysis of soft-substrate macrophytes similarly identified significant increases in cover with decreasing concentrations of total nitrogen and increasing salinity, but the resulting empirical model explained only 52% of the variation in cover, probably due to the spatially more variable nature of soft-substrate vegetation. The identified general responses of vegetation cover to gradients of eutrophication across wide ranges in environmental settings may be useful for monitoring and management of marine vegetation in areas with strong environmental gradients.
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NASA Astrophysics Data System (ADS)
Mounir El-Kahawy, Ramadan; El-Wahab, Mohamed Abd
2017-04-01
Benthic foraminiferal assemblages were investigated at Hurghada on the Red Sea coast of Egypt, to determine the distribution and their common environmental factors that control on this distribution. 43 sediment samples were collected and environmental factors (T°C, pH, and salinity ‰), water depth, grain size, organic matter and carbonate content were measured. Faunal abundance (14-1755 tests/g) with an average 709 tests/g, and faunal diversity (6-39 specimens) with an average 31 specimen. Cluster analysis was divided the Hurghada site into four distinct biotopes based on the faunal data: Biotope (1) is dominated by a Quinqueloculina seminula& Quinqueloculina laevigata, and Triloculina terquemiana assemblage. Biotope (2) is dominated by a Sorites marginalis & Triloculina trigonula assemblage. Biotope (3) is dominated by an Amphistegina lessonii, Ammonia beccarii and Elphidium spp assemblage. Biotope (4) is dominated by a Peneroplis planatus& Coscinospira hemprichii& Sorites orbiculus and Neorotalia calcar assemblage. Some of the recorded foraminiferal tests showed abnormalities in their apertures, coiling and shape of chambers. The distribution of benthic foraminiferal species is governed by environmental factors such as salinity, temperature, substrates-type, water depth and pH. P. planatus and C. hemprichii positively correlate with extreme salinity and temperature, indicating that these species reflect a warm, arid climate conditions. Aside, the heavy metals (Cu, Cd, Zn, Pb, Ni and Mn) concentrations in the sediment samples were analyzed using ICP-OES. The comparative study between the faunal content and the heavy metals enrichments in each sample displayed positive character indicating the worsening of the environmental conditions. Keywords: benthic foraminifera, Hurghada, Red Sea, Egypt
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Ariel E. Lugo; Ernesto Medina
2014-01-01
The mangrove environment is not globally homogeneous, but involves many environmental gradients to which mangrove species must adapt and overcome to maintain the familiar structure and physiognomy associated with the mangrove ecosystem. The stature of mangroves, measured by tree height, decreases along the following environmental gradients from low to high salinity,...
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Environmental and Hydroclimatic Sensitivities of Greenhouse Gas (GHG) Fluxes from Coastal Wetlands
NASA Astrophysics Data System (ADS)
Abdul-Aziz, O. I.; Ishtiaq, K. S.
2016-12-01
We computed the reference environmental and hydroclimatic sensitivities of the greenhouse gas (GHG) fluxes (CO2 and CH4) from coastal salt marshes. Non-linear partial least squares regression models of CO2 (net uptake) and CH4 (net emissions) fluxes were developed with a bootstrap resampling approach using the photosynthetically active radiation (PAR), air and soil temperatures, water height, soil moisture, porewater salinity, and pH as predictors. Analytical sensitivity coefficients of different predictors were then analytically derived from the estimated models. The numerical sensitivities of the dominant drivers were determined by perturbing the variables individually and simultaneously to compute their individual and combined (respectively) effects on the GHG fluxes. Four tidal wetlands of Waquoit Bay, MA — incorporating a gradient in land-use, salinity and hydrology — were considered as the case study sites. The wetlands were dominated by native Spartina Alterniflora, and characterized by high salinity and frequent flooding. Results indicated a high sensitivity of CO2 fluxes to temperature and PAR, a moderate sensitivity to soil salinity and water height, and a weak sensitivity to pH and soil moisture. In contrast, the CH4 fluxes were more sensitive to temperature and salinity, compared to that of PAR, pH, and hydrologic variables. The estimated sensitivities and mechanistic insights can aid the management of coastal carbon under a changing climate and environment. The sensitivity coefficients also indicated the most dominant drivers of GHG fluxes for the development of a parsimonious predictive model.
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Lavaud, Romain; LaPeyre, Megan K.; Casas, Sandra M.; Bacher, C.; La Peyre, Jerome F.
2017-01-01
We present a Dynamic Energy Budget (DEB) model for the eastern oyster, Crassostrea virginica, which enables the inclusion of salinity as a third environmental variable, on top of the standard foodr and temperature variables. Salinity changes have various effects on the physiology of oysters, potentially altering filtration and respiration rates, and ultimately impacting growth, reproduction and mortality. We tested different hypotheses as to how to include these effects in a DEB model for C. virginica. Specifically, we tested two potential mechanisms to explain changes in oyster shell growth (cm), tissue dry weight (g) and gonad dry weight (g) when salinity moves away from the ideal range: 1) a negative effect on filtration rate and 2) an additional somatic maintenance cost. Comparative simulations of shell growth, dry tissue biomass and dry gonad weight in two monitored sites in coastal Louisiana experiencing salinity from 0 to 28 were statistically analyzed to determine the best hypothesis. Model parameters were estimated through the covariation method, using literature data and a set of specifically designed ecophysiological experiments. The model was validated through independent field studies in estuaries along the northern Gulf of Mexico. Our results suggest that salinity impacts C. virginica’s energy budget predominantly through effects on filtration rate. With an overwhelming number of environmental factors impacting organisms, and increasing exposure to novel and extreme conditions, the mechanistic nature of the DEB model with its ability to incorporate more than the standard food and temperature variables provides a powerful tool to verify hypotheses and predict individual organism performance across a range of conditions.
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Loureiro, Cláudia; Pereira, Joana L; Pedrosa, M Arminda; Gonçalves, Fernando; Castro, Bruno B
2013-01-01
Competition is a major driving force in freshwaters, especially given the cyclic nature and dynamics of pelagic food webs. Competition is especially important in the initial species assortment during colonization and re-colonization events, which depends strongly on the environmental context. Subtle changes, such as saline intrusion, may disrupt competitive relationships and, thus, influence community composition. Bearing this in mind, our objective was to assess whether low salinity levels (using NaCl as a proxy) alter the competitive outcome (measured as the rate of population biomass increase) of Daphnia-Simocephalus experimental microcosms, taking into account interactions with priority effects (sequential species arrival order). With this approach, we aimed to experimentally demonstrate a putative mechanism of differential species sorting in brackish environments or in freshwaters facing secondary salinization. Experiments considered three salinity levels, regarding NaCl added (0.00, 0.75 and 1.50 g L(-1)), crossed with three competition scenarios (no priority, priority of Daphnia over Simocephalus, and vice-versa). At lower NaCl concentrations (0.00 and 0.75 g L(-1)), Daphnia was a significantly superior competitor, irrespective of the species inoculation order, suggesting negligible priority effects. However, the strong decrease in Daphnia population growth at 1.50 g L(-1) alleviated the competitive pressure on Simocephalus, causing an inversion of the competitive outcome in favour of Simocephalus. The intensity of this inversion depended on the competition scenario. This salinity-mediated disruption of the competitive outcome demonstrates that subtle environmental changes produce indirect effects in key ecological mechanisms, thus altering community composition, which may lead to serious implications in terms of ecosystem functioning (e.g. lake regime shifts due to reduced grazing) and biodiversity.
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NASA Astrophysics Data System (ADS)
Thomsen, Jörn; Ramesh, Kirti; Sanders, Trystan; Bleich, Markus; Melzner, Frank
2018-03-01
In estuarine coastal systems such as the Baltic Sea, mussels suffer from low salinity which limits their distribution. Anthropogenic climate change is expected to cause further desalination which will lead to local extinctions of mussels in the low saline areas. It is commonly accepted that mussel distribution is limited by osmotic stress. However, along the salinity gradient, environmental conditions for biomineralization are successively becoming more adverse as a result of reduced [Ca2+] and dissolved inorganic carbon (CT) availability. In larvae, calcification is an essential process starting during early development with formation of the prodissoconch I (PD I) shell, which is completed under optimal conditions within 2 days. Experimental manipulations of seawater [Ca2+] start to impair PD I formation in Mytilus larvae at concentrations below 3 mM, which corresponds to conditions present in the Baltic at salinities below 8 g kg-1. In addition, lowering dissolved inorganic carbon to critical concentrations (< 1 mM) similarly affected PD I size, which was well correlated with calculated ΩAragonite and [Ca2+][HCO3-] / [H+] in all treatments. Comparing results for larvae from the western Baltic with a population from the central Baltic revealed a significantly higher tolerance of PD I formation to lowered [Ca2+] and [Ca2+][HCO3-] / [H+] in the low saline adapted population. This may result from genetic adaptation to the more adverse environmental conditions prevailing in the low saline areas of the Baltic. The combined effects of lowered [Ca2+] and adverse carbonate chemistry represent major limiting factors for bivalve calcification and can thereby contribute to distribution limits of mussels in the Baltic Sea.
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The Salt Overly Sensitive (SOS) pathway: established and emerging roles.
Ji, Hongtao; Pardo, José M; Batelli, Giorgia; Van Oosten, Michael J; Bressan, Ray A; Li, Xia
2013-03-01
Soil salinity is a growing problem around the world with special relevance in farmlands. The ability to sense and respond to environmental stimuli is among the most fundamental processes that enable plants to survive. At the cellular level, the Salt Overly Sensitive (SOS) signaling pathway that comprises SOS3, SOS2, and SOS1 has been proposed to mediate cellular signaling under salt stress, to maintain ion homeostasis. Less well known is how cellularly heterogenous organs couple the salt signals to homeostasis maintenance of different types of cells and to appropriate growth of the entire organ and plant. Recent evidence strongly indicates that different regulatory mechanisms are adopted by roots and shoots in response to salt stress. Several reports have stated that, in roots, the SOS proteins may have novel roles in addition to their functions in sodium homeostasis. SOS3 plays a critical role in plastic development of lateral roots through modulation of auxin gradients and maxima in roots under mild salt conditions. The SOS proteins also play a role in the dynamics of cytoskeleton under stress. These results imply a high complexity of the regulatory networks involved in plant response to salinity. This review focuses on the emerging complexity of the SOS signaling and SOS protein functions, and highlights recent understanding on how the SOS proteins contribute to different responses to salt stress besides ion homeostasis.
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Vuorinen, Ilppo; Hänninen, Jari; Rajasilta, Marjut; Laine, Päivi; Eklund, Jan; Montesino-Pouzols, Federico; Corona, Francesco; Junker, Karin; Meier, H.E.Markus; Dippner, Joachim W.
2015-01-01
Substantial ecological changes occurred in the 1970s in the Northern Baltic during a temporary period of low salinity (S). This period was preceded by an episodic increase in the rainfall over the Baltic Sea watershed area. Several climate models, both global and regional, project an increase in the runoff of the Northern latitudes due to proceeding climate change. The aim of this study is to model, firstly, the effects on Baltic Sea salinity of increased runoff due to projected global change and, secondly, the effects of salinity change on the distribution of marine species. The results suggest a critical shift in the S range 5–7, which is a threshold for both freshwater and marine species distributions and diversity. We discuss several topics emphasizing future monitoring, modelling, and fisheries research. Environmental monitoring and modelling are investigated because the developing alternative ecosystems do not necessarily show the same relations to environment quality factors as the retiring ones. An important corollary is that the observed and modelled S changes considered together with species’ ranges indicate what may appear under a future climate. Consequences could include a shift in distribution areas of marine benthic foundation species and some 40–50 other species, affiliated to these. This change would extend over hundreds of kilometres, in the Baltic Sea and the adjacent North Sea areas. Potential cascading effects, in coastal ecology, fish ecology and fisheries would be extensive, and point out the necessity to develop further the “ecosystem approach in the environmental monitoring”. PMID:25737660
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Salt enrichment of municipal sewage: New prevention approaches in Israel
NASA Astrophysics Data System (ADS)
Weber, Baruch; Avnimelech, Yoram; Juanico, Marcelo
1996-07-01
Wastewater irrigation is an environmentally sound wastewater disposal practice, but sewage is more saline than the supplied fresh water and the salts are recycled together with the water. Salts have negative environmental effects on crops, soils, and groundwater. There are no inexpensive ways to remove the salts once they enter sewage, and the prevention of sewage salt enrichment is the most immediately available solution. The body of initiatives presently structured by the Ministry of the Environment of Israel are herein described, with the aim to contribute to the search for a long-term solution of salinity problems in arid countries. The new initiatives are based on: (1) search for new technologies to reduce salt consumption and discharge into sewage; (2) different technologies to cope with different situations; (3) raising the awareness of the public and industry on the environmental implications of salinity pollution; and (4) an elastic legal approach expressed through new state-of-the-art regulations. The main contributor to the salinity of sewage in Israel is the watersoftening process followed by the meat koshering process. Some of the adopted technical solutions are: the discharge of the brine into the sea, the substitution of sodium by potassium salts in the ion-exchangers, the construction of centralized systems for the supply of soft water in industrial areas, the precipitation of Ca and Mg in the effluents from ion-exchangers and recycling of the NaCI solution, a reduction of the discharge of salts by the meat koshering process, and new membrane technology for salt recovery.
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Krauss, K.W.; Doyle, T.W.; Howard, R.J.
2009-01-01
Plant populations may adapt to environmental conditions over time by developing genetically based morphological or physiological characteristics. For tidal freshwater forested wetlands, we hypothesized that the conditions under which trees developed led to ecotypic difference in response of progeny to hydroperiod. Specifically, we looked for evidence of ecotypic adaptation for tidal flooding at different salinity regimes using growth and ecophysiological characteristics of two tidal and two non-tidal source collections of baldcypress (Taxodium distichum (L.) L.C. Rich) from the southeastern United States. Saplings were subjected to treatments of hydrology (permanent versus tidal flooding) and salinity (0 versus ???2 g l-1) for two and a half growing seasons in a greenhouse environment. Saplings from tidal sources maintained 21-41% lower overall growth and biomass accumulation than saplings from non-tidal sources, while saplings from non-tidal sources maintained 14-19% lower overall rates of net photosynthetic assimilation, leaf transpiration, and stomatal conductance than saplings from tidal sources. However, we found no evidence for growth or physiological enhancement of saplings from tidal sources to tide, or of saplings from non-tidal sources to no tide. All saplings growing under permanent flooding exhibited reduced growth and leaf gas exchange regardless of source, with little evidence for consistent salinity effects across hydroperiods. While we reject our original hypothesis, we suggest that adaptations of coastal baldcypress to broad (rather than narrow) environmental conditions may promote ecophysiological and growth enhancements under a range of global-change-induced stressors, perhaps reflecting a natural resilience to environmental change while precluding adaptations for specific flood regimes.
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Remote Sensing Soil Salinity Map for the San Joaquin Vally, California
NASA Astrophysics Data System (ADS)
Scudiero, E.; Skaggs, T. H.; Anderson, R. G.; Corwin, D. L.
2015-12-01
Soil salinization is a major natural hazard to worldwide agriculture. We present a remote imagery approach that maps salinity within a range (i.e., salinities less than 20 dS m-1, when measured as the electrical conductivity of the soil saturation extract), accuracy, and resolution most relevant to agriculture. A case study is presented for the western San Joaquin Valley (WSJV), California, USA (~870,000 ha of farmland) using multi-year Landsat 7 ETM+ canopy reflectance and the Canopy Response Salinity Index (CRSI). Highly detailed salinity maps for 22 fields (542 ha) established from apparent soil electrical conductivity directed sampling were used as ground-truth (sampled in 2013), totaling over 5000 pixels (30×30 m) with salinity values in the range of 0 to 35.2 dS m-1. Multi-year maximum values of CRSI were used to model soil salinity. In addition, soil type, elevation, meteorological data, and crop type were evaluated as covariates. The fitted model (R2=0.73) was validated: i) with a spatial k-folds (i.e., leave-one-field-out) cross-validation (R2=0.61), ii) versus salinity data from three independent fields (sampled in 2013 and 2014), and iii) by determining the accuracy of the qualitative classification of white crusted land as extremely-saline soils. The effect of land use change is evaluated over 2396 ha in the Broadview Water District from a comparison of salinity mapped in 1991 with salinity predicted in 2013 from the fitted model. From 1991 to 2013 salinity increased significantly over the selected study site, bringing attention to potential negative effects on soil quality of shifting from irrigated agriculture to fallow-land. This is cause for concern since over the 3 years of California's drought (2010-2013) the fallow land in the WSJV increased from 12.7% to 21.6%, due to drastic reduction in water allocations to farmers.
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2014-01-01
Background Salinity plays an important role in shaping coastal marine communities. Near-future climate predictions indicate that salinity will decrease in many shallow coastal areas due to increased precipitation; however, few studies have addressed this issue. The ability of ecosystems to cope with future changes will depend on species’ capacities to acclimatise or adapt to new environmental conditions. Here, we investigated the effects of a strong salinity gradient (the Baltic Sea system – Baltic, Kattegat, Skagerrak) on plasticity and adaptations in the euryhaline barnacle Balanus improvisus. We used a common-garden approach, where multiple batches of newly settled barnacles from each of three different geographical areas along the Skagerrak-Baltic salinity gradient were exposed to corresponding native salinities (6, 15 and 30 PSU), and phenotypic traits including mortality, growth, shell strength, condition index and reproductive maturity were recorded. Results We found that B. improvisus was highly euryhaline, but had highest growth and reproductive maturity at intermediate salinities. We also found that low salinity had negative effects on other fitness-related traits including initial growth and shell strength, although mortality was also lowest in low salinity. Overall, differences between populations in most measured traits were weak, indicating little local adaptation to salinity. Nonetheless, we observed some population-specific responses – notably that populations from high salinity grew stronger shells in their native salinity compared to the other populations, possibly indicating adaptation to differences in local predation pressure. Conclusions Our study shows that B. improvisus is an example of a true brackish-water species, and that plastic responses are more likely than evolutionary tracking in coping with future changes in coastal salinity. PMID:25038588
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Cui, You-Wei; Zhang, Hong-Yu; Ding, Jie-Ran; Peng, Yong-Zhen
2016-04-25
With annual increases in the generation and use of saline wastewater, the need to avoid environmental problems such as eutrophication is critical. A previous study identified ways to start up a halophilic sludge domesticated from estuarine sediments to remove nitrogen from wastewater with a salinity of 30 g/L. This investigation expands that work to explore the impact of salinity on nitrogen removal. This study demonstrated that the mixed halophilic consortia removed nitrogen from wastewater with a salinity of 30-85 g/L. A kinetic analysis showed that halophilic nitrifiers selected based on hypersalinity were characterized by low Ks, μmax and specific ammonium oxidization rates. This explains the decrease in ammonium removal efficiency in the high salinity operational phases. Salinity inhibited ammonia oxidizing bacteria (AOB) activity, as well as the number of dominant AOB, but did not significantly affect the AOB dominant species. Three most dominant AOB lineages in the halophilic sludge were Nitrosomonas marina, Nitrosomonas europaea, and Nitrosococcus mobilis. Nitrosomonas europaea and Nitrosococcus mobilis were mainly affected by salinity, while nitrite accumulation and ammonia loading played the key role in determining the abundance of Nitrosococcus mobilis and Nitrosococcus europaea. The study contributes insights about shifts in halophilic nitrifying bacterial populations.
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Cui, You-Wei; Zhang, Hong-Yu; Ding, Jie-Ran; Peng, Yong-Zhen
2016-01-01
With annual increases in the generation and use of saline wastewater, the need to avoid environmental problems such as eutrophication is critical. A previous study identified ways to start up a halophilic sludge domesticated from estuarine sediments to remove nitrogen from wastewater with a salinity of 30 g/L. This investigation expands that work to explore the impact of salinity on nitrogen removal. This study demonstrated that the mixed halophilic consortia removed nitrogen from wastewater with a salinity of 30–85 g/L. A kinetic analysis showed that halophilic nitrifiers selected based on hypersalinity were characterized by low Ks, μmax and specific ammonium oxidization rates. This explains the decrease in ammonium removal efficiency in the high salinity operational phases. Salinity inhibited ammonia oxidizing bacteria (AOB) activity, as well as the number of dominant AOB, but did not significantly affect the AOB dominant species. Three most dominant AOB lineages in the halophilic sludge were Nitrosomonas marina, Nitrosomonas europaea, and Nitrosococcus mobilis. Nitrosomonas europaea and Nitrosococcus mobilis were mainly affected by salinity, while nitrite accumulation and ammonia loading played the key role in determining the abundance of Nitrosococcus mobilis and Nitrosococcus europaea. The study contributes insights about shifts in halophilic nitrifying bacterial populations. PMID:27109617
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Enwright, Nicholas M.; Griffith, Kereen T.; Osland, Michael J.
2015-11-02
In this study, the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, quantified the potential for landward migration of tidal saline wetlands along the U.S. Gulf of Mexico coast under alternative future sea-level rise and urbanization scenarios. Our analyses focused exclusively on tidal saline wetlands (that is, mangrove forests, salt marshes, and salt flats), and we combined these diverse tidal saline wetland ecosystems into a single grouping, “tidal saline wetland.” Collectively, our approach and findings can provide useful information for scientists and environmental planners working to develop future-focused adaptation strategies for conserving coastal landscapes and the ecosystem goods and services provided by tidal saline wetlands. The primary product of this work is a public dataset that identifies locations where landward migration of tidal saline wetlands is expected to occur under alternative future sea-level rise and urbanization scenarios. In addition to identifying areas where landward migration of tidal saline wetlands is possible because of the absence of barriers, these data also identify locations where landward migration of these wetlands could be prevented by barriers associated with current urbanization, future urbanization, and levees.
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Schofield, Pamela J.; Peterson, Mark S.; Lowe, Michael R.; Brown-Peterson, Nancy J.; Slack, William T.
2011-01-01
The physiological tolerances of non-native fishes is an integral component of assessing potential invasive risk. Salinity and temperature are environmental variables that limit the spread of many non-native fishes. We hypothesised that combinations of temperature and salinity will interact to affect survival, growth, and reproduction of Nile tilapia, Oreochromis niloticus, introduced into Mississippi, USA. Tilapia withstood acute transfer from fresh water up to a salinity of 20 and survived gradual transfer up to 60 at typical summertime (30°C) temperatures. However, cold temperature (14°C) reduced survival of fish in saline waters ≥10 and increased the incidence of disease in freshwater controls. Although fish were able to equilibrate to saline waters in warm temperatures, reproductive parameters were reduced at salinities ≥30. These integrated responses suggest that Nile tilapia can invade coastal areas beyond their point of introduction. However, successful invasion is subject to two caveats: (1) wintertime survival depends on finding thermal refugia, and (2) reproduction is hampered in regions where salinities are ≥30. These data are vital to predicting the invasion of non-native fishes into coastal watersheds. This is particularly important given the predicted changes in coastal landscapes due to global climate change and sea-level rise.
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Bacterial Biogeography across the Amazon River-Ocean Continuum
DOE Office of Scientific and Technical Information (OSTI.GOV)
Doherty, Mary; Yager, Patricia L.; Moran, Mary Ann
Spatial and temporal patterns in microbial biodiversity across the Amazon river-ocean continuum were investigated along ~675 km of the lower Amazon River mainstem, in the Tapajos River tributary, and in the plume and coastal ocean during low and high river discharge using amplicon sequencing of 16S rRNA genes in whole water and size-fractionated samples (0.2-2.0 μm and >2.0 μm). River communities varied among tributaries, but mainstem communities were spatially homogeneous and tracked seasonal changes in river discharge and co-varying factors. Co-occurrence network analysis identified strongly interconnected river assemblages during high (May) and low (December) discharge periods, and weakly interconnected transitionalmore » assemblages in September, suggesting that this system supports two seasonal microbial communities linked to river discharge. In contrast, plume communities showed little seasonal differences and instead varied spatially tracking salinity. However, salinity explained only a small fraction of community variability, and plume communities in blooms of diatom-diazotroph assemblages were strikingly different than those in other high salinity plume samples. This suggests that while salinity physically structures plumes through buoyancy and mixing, the composition of plume-specific communities is controlled by other factors including nutrients, phytoplankton community composition, and dissolved organic matter chemistry. Co-occurrence networks identified interconnected assemblages associated with the highly productive low salinity nearshore region, diatom-diazotroph blooms, and the plume edge region, and weakly interconnected assemblages in high salinity regions. This suggests that the plume supports a transitional community influenced by immigration of ocean bacteria from the plume edge, and by species sorting as these communities adapt to local environmental conditions. Few studies have explored patterns of microbial diversity in tropical rivers and coastal oceans. Comparison of Amazon continuum microbial communities to those from temperate and arctic systems suggest that river discharge and salinity are master variables structuring a range of environmental conditions that control bacterial communities across the river-ocean continuum.« less
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Bacterial Biogeography across the Amazon River-Ocean Continuum.
Doherty, Mary; Yager, Patricia L; Moran, Mary Ann; Coles, Victoria J; Fortunato, Caroline S; Krusche, Alex V; Medeiros, Patricia M; Payet, Jérôme P; Richey, Jeffrey E; Satinsky, Brandon M; Sawakuchi, Henrique O; Ward, Nicholas D; Crump, Byron C
2017-01-01
Spatial and temporal patterns in microbial biodiversity across the Amazon river-ocean continuum were investigated along ∼675 km of the lower Amazon River mainstem, in the Tapajós River tributary, and in the plume and coastal ocean during low and high river discharge using amplicon sequencing of 16S rRNA genes in whole water and size-fractionated samples (0.2-2.0 μm and >2.0 μm). River communities varied among tributaries, but mainstem communities were spatially homogeneous and tracked seasonal changes in river discharge and co-varying factors. Co-occurrence network analysis identified strongly interconnected river assemblages during high (May) and low (December) discharge periods, and weakly interconnected transitional assemblages in September, suggesting that this system supports two seasonal microbial communities linked to river discharge. In contrast, plume communities showed little seasonal differences and instead varied spatially tracking salinity. However, salinity explained only a small fraction of community variability, and plume communities in blooms of diatom-diazotroph assemblages were strikingly different than those in other high salinity plume samples. This suggests that while salinity physically structures plumes through buoyancy and mixing, the composition of plume-specific communities is controlled by other factors including nutrients, phytoplankton community composition, and dissolved organic matter chemistry. Co-occurrence networks identified interconnected assemblages associated with the highly productive low salinity near-shore region, diatom-diazotroph blooms, and the plume edge region, and weakly interconnected assemblages in high salinity regions. This suggests that the plume supports a transitional community influenced by immigration of ocean bacteria from the plume edge, and by species sorting as these communities adapt to local environmental conditions. Few studies have explored patterns of microbial diversity in tropical rivers and coastal oceans. Comparison of Amazon continuum microbial communities to those from temperate and arctic systems suggest that river discharge and salinity are master variables structuring a range of environmental conditions that control bacterial communities across the river-ocean continuum.
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Net ecosystem calcification and net primary production in two Hawaii back-reef systems
NASA Astrophysics Data System (ADS)
Kiili, S.; Colbert, S.; Hart, K.
2016-02-01
Back-reef systems have complex carbon cycling, driven by dominant benthic communities that change with environmental conditions and display characteristic patterns of net primary production (NP) and net ecosystem calcification (G). The G/NP ratio provides a fundamental community-level assessment to compare systems spatially and to evaluate temporal changes in carbon cycling. Carbon dynamics were examined at leeward Hōnaunau and windward Waíōpae, Hawaíi Island. Both locations discharge brackish groundwater, including geothermal water at Waíōpae. The change in total CO2 (TCO2) and total alkalinity (TA) between morning and afternoon was measured to calculate the G/NP ratio along a salinity gradient. At both sites, aragonite saturation (ΩAr) was lower than open ocean conditions, and increased with salinity. Between the morning and afternoon, ΩAr increased by at least 1 as photosynthesis consumed CO2. At Waíōpae, water was corrosive to aragonite due to the input of acidic groundwater, but not at Honaunau, demonstrating the importance of local watershed characteristics on ΩAr. Across the salinity gradient, TA and TCO2 decreased between morning and afternoon. At Hōnaunau, G/NP increased from 0.11 to 0.31 with salinity, consistent with an offshore increase in coral cover. But at Waíōpae, G/NP decreased from 0.49 to 0.0 with salinity, despite an increase in coral cover with salinity. Low G may be caused by benthic processes, including coral bleaching or high rates of carbonate dissolution in interstitial waters between tide pools. Broader environmental conditions than just salinity, including pH of fresh groundwater inputs, shape the carbon cycling in the back-reef system. Examining the G/NP ratio of a back-reef system allows for a simple method to establish community level activity, and possibly indicate changes in a dynamic system.
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Bacterial Biogeography across the Amazon River-Ocean Continuum
Doherty, Mary; Yager, Patricia L.; Moran, Mary Ann; ...
2017-05-23
Spatial and temporal patterns in microbial biodiversity across the Amazon river-ocean continuum were investigated along ~675 km of the lower Amazon River mainstem, in the Tapajos River tributary, and in the plume and coastal ocean during low and high river discharge using amplicon sequencing of 16S rRNA genes in whole water and size-fractionated samples (0.2-2.0 μm and >2.0 μm). River communities varied among tributaries, but mainstem communities were spatially homogeneous and tracked seasonal changes in river discharge and co-varying factors. Co-occurrence network analysis identified strongly interconnected river assemblages during high (May) and low (December) discharge periods, and weakly interconnected transitionalmore » assemblages in September, suggesting that this system supports two seasonal microbial communities linked to river discharge. In contrast, plume communities showed little seasonal differences and instead varied spatially tracking salinity. However, salinity explained only a small fraction of community variability, and plume communities in blooms of diatom-diazotroph assemblages were strikingly different than those in other high salinity plume samples. This suggests that while salinity physically structures plumes through buoyancy and mixing, the composition of plume-specific communities is controlled by other factors including nutrients, phytoplankton community composition, and dissolved organic matter chemistry. Co-occurrence networks identified interconnected assemblages associated with the highly productive low salinity nearshore region, diatom-diazotroph blooms, and the plume edge region, and weakly interconnected assemblages in high salinity regions. This suggests that the plume supports a transitional community influenced by immigration of ocean bacteria from the plume edge, and by species sorting as these communities adapt to local environmental conditions. Few studies have explored patterns of microbial diversity in tropical rivers and coastal oceans. Comparison of Amazon continuum microbial communities to those from temperate and arctic systems suggest that river discharge and salinity are master variables structuring a range of environmental conditions that control bacterial communities across the river-ocean continuum.« less
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Madrid, Eric N.; Armitage, Anna R.; López-Portillo, Jorge
2014-01-01
Over the last several decades, the distribution of the black mangrove Avicennia germinans in the Gulf of Mexico has expanded, in part because it can survive the occasional freeze events and high soil salinities characteristic of the area. Vessel architecture may influence mangrove chilling and salinity tolerance. We surveyed populations of A. germinans throughout the Gulf to determine if vessel architecture was linked to field environmental conditions. We measured vessel density, hydraulically weighted vessel diameter, potential conductance capacity, and maximum tensile fracture stress. At each sampling site we recorded mangrove canopy height and soil salinity, and determined average minimum winter temperature from archived weather records. At a subset of sites, we measured carbon fixation rates using a LI-COR 6400XT Portable Photosynthesis System. Populations of A. germinans from cooler areas (Texas and Louisiana) had narrower vessels, likely reducing the risk of freeze-induced embolisms but also decreasing water conductance capacity. Vessels were also narrower in regions with high soil salinity, including Texas, USA and tidal flats in Veracruz, Mexico. Vessel density did not consistently vary with temperature or soil salinity. In abiotically stressful areas, A. germinans had a safe hydraulic architecture with narrower vessels that may increase local survival. This safe architecture appears to come at a substantial physiological cost in terms of reduction in conductance capacity and carbon fixation potential, likely contributing to lower canopy heights. The current distribution of A. germinans in the Gulf is influenced by the complex interplay between temperature, salinity, and vessel architecture. Given the plasticity of A. germinans vessel characters, it is likely that this mangrove species will be able to adapt to a wide range of potential future environmental conditions, and continue its expansion in the Gulf of Mexico in response to near-term climate change. PMID:25309570
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Bacterial Biogeography across the Amazon River-Ocean Continuum
Doherty, Mary; Yager, Patricia L.; Moran, Mary Ann; Coles, Victoria J.; Fortunato, Caroline S.; Krusche, Alex V.; Medeiros, Patricia M.; Payet, Jérôme P.; Richey, Jeffrey E.; Satinsky, Brandon M.; Sawakuchi, Henrique O.; Ward, Nicholas D.; Crump, Byron C.
2017-01-01
Spatial and temporal patterns in microbial biodiversity across the Amazon river-ocean continuum were investigated along ∼675 km of the lower Amazon River mainstem, in the Tapajós River tributary, and in the plume and coastal ocean during low and high river discharge using amplicon sequencing of 16S rRNA genes in whole water and size-fractionated samples (0.2–2.0 μm and >2.0 μm). River communities varied among tributaries, but mainstem communities were spatially homogeneous and tracked seasonal changes in river discharge and co-varying factors. Co-occurrence network analysis identified strongly interconnected river assemblages during high (May) and low (December) discharge periods, and weakly interconnected transitional assemblages in September, suggesting that this system supports two seasonal microbial communities linked to river discharge. In contrast, plume communities showed little seasonal differences and instead varied spatially tracking salinity. However, salinity explained only a small fraction of community variability, and plume communities in blooms of diatom-diazotroph assemblages were strikingly different than those in other high salinity plume samples. This suggests that while salinity physically structures plumes through buoyancy and mixing, the composition of plume-specific communities is controlled by other factors including nutrients, phytoplankton community composition, and dissolved organic matter chemistry. Co-occurrence networks identified interconnected assemblages associated with the highly productive low salinity near-shore region, diatom-diazotroph blooms, and the plume edge region, and weakly interconnected assemblages in high salinity regions. This suggests that the plume supports a transitional community influenced by immigration of ocean bacteria from the plume edge, and by species sorting as these communities adapt to local environmental conditions. Few studies have explored patterns of microbial diversity in tropical rivers and coastal oceans. Comparison of Amazon continuum microbial communities to those from temperate and arctic systems suggest that river discharge and salinity are master variables structuring a range of environmental conditions that control bacterial communities across the river-ocean continuum. PMID:28588561
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Madrid, Eric N; Armitage, Anna R; López-Portillo, Jorge
2014-01-01
Over the last several decades, the distribution of the black mangrove Avicennia germinans in the Gulf of Mexico has expanded, in part because it can survive the occasional freeze events and high soil salinities characteristic of the area. Vessel architecture may influence mangrove chilling and salinity tolerance. We surveyed populations of A. germinans throughout the Gulf to determine if vessel architecture was linked to field environmental conditions. We measured vessel density, hydraulically weighted vessel diameter, potential conductance capacity, and maximum tensile fracture stress. At each sampling site we recorded mangrove canopy height and soil salinity, and determined average minimum winter temperature from archived weather records. At a subset of sites, we measured carbon fixation rates using a LI-COR 6400XT Portable Photosynthesis System. Populations of A. germinans from cooler areas (Texas and Louisiana) had narrower vessels, likely reducing the risk of freeze-induced embolisms but also decreasing water conductance capacity. Vessels were also narrower in regions with high soil salinity, including Texas, USA and tidal flats in Veracruz, Mexico. Vessel density did not consistently vary with temperature or soil salinity. In abiotically stressful areas, A. germinans had a safe hydraulic architecture with narrower vessels that may increase local survival. This safe architecture appears to come at a substantial physiological cost in terms of reduction in conductance capacity and carbon fixation potential, likely contributing to lower canopy heights. The current distribution of A. germinans in the Gulf is influenced by the complex interplay between temperature, salinity, and vessel architecture. Given the plasticity of A. germinans vessel characters, it is likely that this mangrove species will be able to adapt to a wide range of potential future environmental conditions, and continue its expansion in the Gulf of Mexico in response to near-term climate change.
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Charrieau, Laurie M; Filipsson, Helena L; Nagai, Yukiko; Kawada, Sachiko; Ljung, Karl; Kritzberg, Emma; Toyofuku, Takashi
2018-07-01
Coastal areas display natural large environmental variability such as frequent changes in salinity, pH, and carbonate chemistry. Anthropogenic impacts - especially ocean acidification - increase this variability, which may affect the living conditions of coastal species, particularly, calcifiers. We performed culture experiments on living benthic foraminifera to study the combined effects of lowered pH and salinity on the calcification abilities and survival of the coastal, calcitic species Ammonia sp. and Elphidium crispum. We found that in open ocean conditions (salinity ∼35) and lower pH than usual values for these species, the specimens displayed resistance to shell (test) dissolution for a longer time than in brackish conditions (salinity ∼5 to 20). However, the response was species specific as Ammonia sp. specimens survived longer than E. crispum specimens when placed in the same conditions of salinity and pH. Living, decalcified juveniles of Ammonia sp. were observed and we show that desalination is one cause for the decalcification. Finally, we highlight the ability of foraminifera to survive under Ω calc < 1, and that high salinity and [Ca 2+ ] as building blocks are crucial for the foraminiferal calcification process. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Li, Ran; Jiao, Nianzhi; Warren, Alan; Xu, Dapeng
2018-04-01
Protists make up an important component of aquatic ecosystems, playing crucial roles in biogeochemical processes on local and global scales. To reveal the changes of diversity and community structure of protists along the salinity gradients, community compositions of active protistan assemblages were characterized along a transect from the lower Pearl River estuary to the open waters of the South China Sea (SCS), using high-throughput sequencing of the hyper-variable V9 regions of 18S rRNA. This study showed that the alpha diversity of protists, both in the freshwater and in the coastal SCS stations was higher than that in the estuary. The protist community structure also changed along the salinity gradient. The relative sequence abundance of Stramenopiles was highest at stations with lower salinity and decreased with the increasing of salinity. By contrast, the contributions of Alveolata, Hacrobia and Rhizaria to the protistan communities generally increased with the increasing of salinity. The composition of the active protistan community was strongly correlated with salinity, indicating that salinity was the dominant factor among measured environmental parameters affecting protistan community composition and structure. Copyright © 2018 Elsevier GmbH. All rights reserved.
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Thombre, Rebecca S; Shinde, Vinaya D; Oke, Radhika S; Dhar, Sunil Kumar; Shouche, Yogesh S
2016-05-27
Haloarchaea are unique microorganism's resistant to environmental and osmotic stresses and thrive in their habitats despite extreme fluctuating salinities. In the present study, haloarchaea were isolated from hypersaline thalossohaline salterns of Bhandup, Mumbai, India and were identified as Haloferax prahovense, Haloferax alexandrines, Haloferax lucentense, Haloarcula tradensis, Haloarcula marismortui and Haloarcula argentinensis. The mechanism of adaptation to contrasting salinities (1.5 M and 4.5 M) was investigated in the extreme haloarchaeon, Hal. marismortui RR12. Hal. marismortui RR12 increased the intracellular sequestration of K(+) and Cl(-) ions in hypo salinity and hyper salinity respectively as detected by Energy-dispersive X-ray spectroscopy microanalysis (EDAX) and Inductively Coupled Plasma- atomic Emission Spectroscopy (ICP-AES) indicating the presence of 'salt-in' strategy of osmoadaptation. As a cellular response to salinity stress, it produced small heat shock like proteins (sHSP) identified using MALDI-TOF MS and increased the production of protective red carotenoid pigment. This is the first report on the study of the concomitant cellular, molecular and physiological mechanism adapted by Hal. marismortui RR12 when exposed to contrasting salinities in external environment.
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The effects of salinity and temperature shock on Kappaphycus alvarezii seaweed spores release
NASA Astrophysics Data System (ADS)
Harwinda, F. K.; Satyantini, W. H.; Masithah, E. W.
2018-04-01
One of the reproductive aspects of development step that is considered as the solution of this issue is seaweed sporulation technique through which is induced through salinity and temperature shock. This study aims to determine the effect of combination and interaction of salinity and temperature shock on the release of K. alvarezii spores in order to produce superior seeds. This research was conducted using Complete Randomized Design Factorial which consists of nine combinations of treatments and three replications. The used treatment in this study is the combination of different environmental factors such as salinity shock and temperature shock. The data were analyzed using ANOVA (Analysis of Variance) followed by Duncan Multiple Range Test. The results showed that salinity (31 ppt, 33 ppt, and 35 ppt) and temperature (30°C, 32°C, and 34°C). shock affected the osmoregulation system and the release of K. alvarezii spores. The salinity shock and temperature shock had interaction with K. alvarezii spore release on the sixth and seventh day with the best treatment at 32°C temperature and 31 ppt salinity and released 5413 cells/ml spores on the seventh day.
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NASA Astrophysics Data System (ADS)
Hoppe, H.-G.; Giesenhagen, H. C.; Koppe, R.; Hansen, H.-P.; Gocke, K.
2013-07-01
Phytoplankton and bacteria are sensitive indicators of environmental change. The temporal development of these key organisms was monitored from 1988 to the end of 2007 at the time series station Boknis Eck in the western Baltic Sea. This period was characterized by the adaption of the Baltic Sea ecosystem to changes in the environmental conditions caused by the conversion of the political system in the southern and eastern border states, accompanied by the general effects of global climate change. Measured variables were chlorophyll, primary production, bacteria number, -biomass and -production, glucose turnover rate, macro-nutrients, pH, temperature and salinity. Negative trends with time were recorded for chlorophyll, bacteria number, bacterial biomass and bacterial production, nitrate, ammonia, phosphate, silicate, oxygen and salinity while temperature, pH, and the ratio between bacteria numbers and chlorophyll increased. Strongest reductions with time occurred for the annual maximum values, e.g. for chlorophyll during the spring bloom or for nitrate during winter, while the annual minimum values remained more stable. In deep water above sediment the negative trends of oxygen, nitrate, phosphate and bacterial variables as well as the positive trend of temperature were similar to those in the surface while the trends of salinity, ammonia and silicate were opposite to those in the surface. Decreasing oxygen, even in the surface layer, was of particular interest because it suggested enhanced recycling of nutrients from the deep hypoxic zones to the surface by vertical mixing. The long-term seasonal patterns of all variables correlated positively with temperature, except chlorophyll and salinity. Salinity correlated negatively with all bacterial variables (as well as precipitation) and positively with chlorophyll. Surprisingly, bacterial variables did not correlate with chlorophyll, which may be inherent with the time lag between the peaks of phytoplankton and bacteria during spring. Compared to the 20-yr averages of the environmental and microbial variables, the strongest negative deviations of corresponding annual averages were measured about ten years after political change for nitrate and bacterial secondary production (~ -60%), followed by chlorophyll (-50%) and bacterial biomass (-40%). Considering the circulation of surface currents in the Baltic Sea we interpret the observed patterns of the microbial variables at the Boknis Eck time series station as a consequence of the improved management of water resources after 1989 and - to a minor extent - the trends of the climate variables salinity and temperature.
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NASA Astrophysics Data System (ADS)
Hoppe, H.-G.; Giesenhagen, H. C.; Koppe, R.; Hansen, H.-P.; Gocke, K.
2012-12-01
Phytoplankton and bacteria are sensitive indicators of environmental change. The temporal development of these key organisms was monitored from 1988 to the end of 2007 at the time series station Boknis Eck in the Western Baltic Sea. This period was characterized by the adaption of the Baltic Sea ecosystem to changes in the environmental conditions caused by the collapse and conversion of the political system in the Southern and Eastern Border States, accompanied by the general effects of global climate change. Measured variables were chlorophyll, primary production, bacteria number, -biomass and -production, glucose turnover rate, macro-nutrients, pH, temperature and salinity. Negative trends with time were recorded for chlorophyll, the bacterial variables, nitrate, ammonia, phosphate, silicate, oxygen and salinity while temperature, pH, and the ratio between bacteria numbers and chlorophyll increased. The strongest reductions with time occurred for the annual maximum values, e.g. for chlorophyll during the spring bloom or for nitrate during winter, while the annual minimum values remained more stable. In deep water above sediment the negative trends of oxygen, nitrate, phosphate and bacterial variables as well as the positive trend of temperature were similar to those in the surface while the trends of salinity, ammonia and silicate were opposite to those in the surface. Decreasing oxygen even in the surface layer was of particular interest because it suggested enhanced recycling of nutrients from the deep hypoxic zones to the surface by vertical mixing. In the long run all variables correlated positively with temperature, except chlorophyll and salinity. Salinity correlated negatively with all bacterial variables as well as precipitation and positively with chlorophyll. Surprisingly, bacterial variables did not correlate with chlorophyll which may be inherent with the time lag between the peaks of phytoplankton and bacteria during spring. Compared to the 20-yr averages of the environmental and microbial variables, the strongest negative deviations of corresponding annual averages were measured about ten years after political change for nitrate and bacterial secondary production (~ -60%), followed by chlorophyll (-50%) and bacterial biomass (-40%). Considering the circulation of surface currents in the Baltic Sea we conclude that the improved management of water resources after 1989 together with the trends of the climate variables salinity and temperature were responsible for the observed patterns of the microbial variables at the Boknis Eck time series station.
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NASA Astrophysics Data System (ADS)
Ngo, N.
2005-12-01
Although the potential causes of harmful algal blooms (HABs), or red tides, have been studied extensively, the relationships between the environmental drivers and economic impacts have not been fully explored. This paper examined the environmental-economic link by investigating similarities in the environmental conditions leading to the 1993 and 2005 HABs (caused by the dinoflagellate Alexandirum) along the Massachusetts coast, and the resulting effects on shellfish, public health, recreation, tourism, and the commercial shellfish industry in Massachusetts. Environmental influences including sea surface temperature (SST), salinity, precipitation, streamflow, and shellfish toxicity levels were examined for the years 1990 to 2005. Economic impacts on commercial fishery landings (Massachusetts mussel commercial fishery landings and Gloucester commercial fishery landings) were assessed for the years1990 to 2003. The Plume Advection hypothesis was studied and results showed that runoff from the five major rivers that contribute to the Western Maine Coastal Current, the current that carried these cells, peaked in April 1993 and 2005 relative to the mean which varied from river to river. The most intense wind stress coming from the North occurred in April 1993 and May 2005 with speeds of 15-20 m/s. A large decrease in salinity off the Massachusetts coast occurred in May 1993 and measured outside the 68% of 1993 salinity data recorded, and from the information available, in April and May 2005 waters were also less saline. Peaks in shellfish toxicity occurred in early June 1993 at approximately 400 μg toxicity/g shellfish meat and in 2005 at 700 μg toxicity/g shellfish meat. This indicated a lag time between peaks in runoff and toxicity of approximately one month and similarly with decreases in salinity. Runoff also corresponded to a large decrease in salinity during May 1993. Coincidentally, there was also a significant decrease in commercial fishery landings between 1992 and 1993, resulting in a decrease of millions of dollars of revenue for shellfish fishermen and the state of Massachusetts. The 2005 red tide affected 1700 shellfish fisherman and there was a projected loss of 527 million dollars for the 2005 Massachusetts shellfish season. Effects to tourism and public health for 1993 and 2005 were challenging to assess, however, due to scarcity of accurate information. Changing fishery policies affected commercial fishery landings during the same time and were also considered. These results argue for more accurate forecasts that will help predict future HABs, as well as improved methods to provide more reliable information on the economic impacts of HABs to minimize the negative impacts of future HABs.
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Current purpose and practice of hypertonic saline in neurosurgery: a review of the literature.
Thongrong, Cattleya; Kong, Nicolas; Govindarajan, Barani; Allen, Duane; Mendel, Ehud; Bergese, Sergio D
2014-12-01
To review and summarize controversies and current concepts regarding the use of hypertonic saline during the perioperative period in neurosurgery. Relevant literature was searched on PubMed and Scopus electronic databases to identify all studies that have investigated the use of hypertonic saline in neurosurgery. Fluid management during the course of neurosurgical practice has been debated at length, especially strategies to control intracranial pressure and small volume resuscitation. The goal of fluid therapy includes minimizing cerebral edema, preserving intravascular volume, and maintaining cerebral perfusion pressure. Mannitol is widely recognized as the gold standard for treating intracranial hypertension but can result in systemic hypotension. Thus, hypertonic saline provides volume expansion and may improve cerebral and systemic hemodynamics. Recently published prospective data, however, regarding the use of osmotic agents fails to establish clear guidelines in neurosurgical patients. We suggest that hypertonic saline will emerge as an alternative to mannitol, especially for a long-term use or multiple doses are needed and lead to a great opportunity for collaborative research. Copyright © 2014 Elsevier Inc. All rights reserved.
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Kim, Taeyoung; Rahimi, Mohammad; Logan, Bruce E; Gorski, Christopher A
2016-05-10
Mixing entropy batteries (MEBs) are a new approach to generate electricity from salinity differences between two aqueous solutions. To date, MEBs have only been prepared from solutions containing chloride salts, owing to their relevance in natural salinity gradients created from seawater and freshwater. We hypothesized that MEBs could capture energy using ammonium bicarbonate (AmB), a thermolytic salt that can be used to convert waste heat into salinity gradients. We examined six battery electrode materials. Several of the electrodes were unstable in AmB solutions or failed to produce expected voltages. Of the electrode materials tested, a cell containing a manganese oxide electrode and a metallic lead electrode produced the highest power density (6.3 mW m(-2) ). However, this power density is still low relative to previously reported NaCl-based MEBs and heat recovery systems. This proof-of-concept study demonstrated that MEBs could indeed be used to generate electricity from AmB salinity gradients. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Environmental Benefits and Burdens of Phosphorus Recovery from Municipal Wastewater.
Bradford-Hartke, Zenah; Lane, Joe; Lant, Paul; Leslie, Gregory
2015-07-21
The environmental benefits and burdens of phosphorus recovery in four centralized and two decentralized municipal wastewater systems were compared using life cycle assessment (LCA). In centralized systems, phosphorus recovered as struvite from the solids dewatering liquid resulted in an environmental benefit except for the terrestrial ecotoxicity and freshwater eutrophication impact categories, with power and chemical use offset by operational savings and avoided fertilizer production. Chemical-based phosphorus recovery, however, generally required more resources than were offset by avoided fertilizers, resulting in a net environmental burden. In decentralized systems, phosphorus recovery via urine source separation reduced the global warming and ozone depletion potentials but increased terrestrial ecotoxicity and salinization potentials due to application of untreated urine to land. Overall, mineral depletion and eutrophication are well-documented arguments for phosphorus recovery; however, phosphorus recovery does not necessarily present a net environmental benefit. While avoided fertilizer production does reduce potential impacts, phosphorus recovery does not necessarily offset the resources consumed in the process. LCA results indicate that selection of an appropriate phosphorus recovery method should consider both local conditions and other environmental impacts, including global warming, ozone depletion, toxicity, and salinization, in addition to eutrophication and mineral depletion impacts.
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Brennan, Reid S; Galvez, Fernando; Whitehead, Andrew
2015-04-15
The killifish Fundulus heteroclitus is an estuarine species with broad physiological plasticity, enabling acclimation to diverse stressors. Previous work suggests that freshwater populations expanded their physiology to accommodate low salinity environments; however, it is unknown whether this compromises their tolerance to high salinity. We used a comparative approach to investigate the mechanisms of a derived freshwater phenotype and the fate of an ancestral euryhaline phenotype after invasion of a freshwater environment. We compared physiological and transcriptomic responses to high- and low-salinity stress in fresh and brackish water populations and found an enhanced plasticity to low salinity in the freshwater population coupled with a reduced ability to acclimate to high salinity. Transcriptomic data identified genes with a conserved common response, a conserved salinity-dependent response and responses associated with population divergence. Conserved common acclimation responses revealed stress responses and alterations in cell-cycle regulation as important mechanisms in the general osmotic response. Salinity-specific responses included the regulation of genes involved in ion transport, intracellular calcium, energetic processes and cellular remodeling. Genes diverged between populations were primarily those showing salinity-specific expression and included those regulating polyamine homeostasis and the cell cycle. Additionally, when populations were matched with their native salinity, expression patterns were consistent with the concept of 'transcriptomic resilience', suggesting local adaptation. These findings provide insight into the fate of a plastic phenotype after a shift in environmental salinity and help to reveal mechanisms allowing for euryhalinity. © 2015. Published by The Company of Biologists Ltd.
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Environmental and ecological impacts of water supplement schemes in a heavily polluted estuary.
Su, Qiong; Qin, Huapeng; Fu, Guangtao
2014-02-15
Water supplement has been used to improve water quality in a heavily polluted river with small base flow. However, its adverse impacts particularly on nearby sensitive ecosystems have not been fully investigated in previous studies. In this paper, using the Shenzhen River estuary in China as a case study, the impacts of two potential water supplement schemes (reclaimed water scheme and seawater scheme) on water quality improvement and salinity alteration of the estuary are studied. The influences of salinity alteration on the dominant mangrove species (Aegiceras corniculatum, Kandelia candel, and Avicennia marina) are further evaluated by comparing the alteration with the historical salinity data and the optimum salinity range for mangrove growth. The results obtained indicate that the targets of water quality improvement can be achieved by implementing the water supplement schemes with roughly the same flow rates. The salinity under the reclaimed water scheme lies in the range of historical salinity variation, and its average value is close to the optimum salinity for mangrove growth. Under the seawater scheme, however, the salinity in the estuary exceeds the range of historical salinity variation and approaches to the upper bound of the survival salinity of the mangrove species which have a relatively low salt tolerance (e.g. A. corniculatum). Therefore, the seawater scheme has negative ecological consequences, while the reclaimed water scheme has less ecological impact and is recommended in this study. Copyright © 2013 Elsevier B.V. All rights reserved.
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Salinization of aquifers at the regional scale by marine transgression: Time scales and processes
NASA Astrophysics Data System (ADS)
Armandine Les Landes, A.; Davy, P.; Aquilina, L.
2014-12-01
Saline fluids with moderate concentrations have been sampled and reported in the Armorican basement at the regional scale (northwestern France). The horizontal and vertical distributions of high chloride concentrations (60-1400mg/L) at the regional scale support the marine origin and provide constraints on the age of these saline fluids. The current distribution of fresh and "saline" groundwater at depth is the result mostly of processes occurring at geological timescales - seawater intrusion processes followed by fresh groundwater flushing -, and only slightly of recent anthropogenic activities. In this study, we focus on seawater intrusion mechanisms in continental aquifers. We argue that one of the most efficient processes in macrotidal environments is the gravity-driven downconing instability below coastal salinized rivers. 2-D numerical experiments have been used to quantify this process according to four main parameter types: (1) the groundwater system permeability, (2) the salinity degree of the river, (3) the river width and slope, and (4) the tidal amplitude. A general expression of the salinity inflow rates have been derived, which has been used to estimate groundwater salinization rates in Brittany, given the geomorphological and environmental characteristics (drainage basin area, river widths and slopes, tidal range, aquifer permeability). We found that downconing below coastal rivers entail very high saline rates, indicating that this process play a major role in the salinization of regional aquifers. This is also likely to be an issue in the context of climate change, where sea-level rise is expected.
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Howard, R.J.
2010-01-01
Genetic diversity within plant populations can influence plant community structure along environmental gradients. In wetland habitats, salinity and soil type are factors that can vary along gradients and therefore affect plant growth. To test for intraspecific growth variation in response to these factors, a greenhouse study was conducted using common plants that occur in northern Gulf of Mexico brackish and salt marshes. Individual plants of Distichlis spicata, Phragmites australis, Schoenoplectus californicus, and Schoenoplectus robustus were collected from several locations along the coast in Louisiana, USA. Plant identity, based on collection location, was used as a measure of intraspecific variability. Prepared soil mixtures were organic, silt, or clay, and salinity treatments were 0 or 18 psu. Significant intraspecific variation in stem number, total stem height, or biomass was found in all species. Within species, response to soil type varied, but increased salinity significantly decreased growth in all individuals. Findings indicate that inclusion of multiple genets within species is an important consideration for marsh restoration projects that include vegetation plantings. This strategy will facilitate establishment of plant communities that have the flexibility to adapt to changing environmental conditions and, therefore, are capable of persisting over time. ?? Coastal and Estuarine Research Federation 2009.
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NASA Astrophysics Data System (ADS)
Zhang, X.; Hu, B.
2017-12-01
Seawater intrusion has been an important topic in coastal hydrogeology and making previously freshwater ecosystems saline. Plant and animal responses to variation in the freshwater-saline interface have been well studied in the coastal zone. However, little is known about the biogeography or stability of microbial community response to seawater intrusion. The objective of this study is to characterize and compare bacterial and archaea community diversity and composition in 15 groundwater samples with varied salinity using high-throughput-sequencing of 16S ribosomal RNA genes. The dominant taxonomic group identified in all samples are proteobacteria for bacteria and crenarchaeota for archaea. The other main bacterial groups are varied in samples with different salinities including bacteroidetes, firmicutes and several unidentified taxonomys. A combination of environmental factors seems to influence the microbial community composition where organic carbon is a primary factor shaping microbial communities. Correlation analysis between the relative abundance of bacterial taxa and geochemical parameters uggested that rare taxa may contribute to biogeochemical processes taking place at the mixing zone of freshewater and saltwater. Our results help to understand how the physical and chemical factors shape the microbial community composition and set a baseline for upcoming studies to evaluate the response of this ecosystem to future changes and the efficacy of new remediation efforts.
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Azarnivand, Ali
2015-12-01
Wang et al. (2015) employed driving force-pressure-state-impact-response (DPSIR) framework to provide a robust decision-making structure for carbon emission reduction by use of wolfberry plantation in the Jingtai oasis, China. DPSIR appropriately identified the causes of problem along with adopting the responses to the barriers associated with wolfberry plantation. However, the discusser argues that, the paper could have prepared more viable outcomes, if the authors had used causal network rather than causal chains through the DPSIR framework. Furthermore, they could have quantified the mutual relationship among the relevant factors to provide a detailed economic assessment. With this knowledge in hand, the current discussion letter suggests eDPSIR and meDPSIR to address drawbacks regarding conventional DPSIR framework. Due to proper performance of eDPSIR and meDPSIR, they are recommended as practical tools in the future environmental studies. Copyright © 2015 Elsevier Ltd. All rights reserved.
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The influence of salinity on the effects of Multi-walled carbon nanotubes on polychaetes.
De Marchi, Lucia; Neto, Victor; Pretti, Carlo; Figueira, Etelvina; Chiellini, Federica; Morelli, Andrea; Soares, Amadeu M V M; Freitas, Rosa
2018-06-05
Salinity shifts in estuarine and coastal areas are becoming a topic of concern and are one of the main factors influencing nanoparticles behaviour in the environment. For this reason, the impacts of multi-walled carbon nanotubes (MWCNTs) under different seawater salinity conditions were evaluated on the common ragworm Hediste diversicolor, a polychaete species widely used as bioindicator of estuarine environmental quality. An innovative method to assess the presence of MWCNT aggregates in the sediments was used for the first time. Biomarkers approach was used to evaluate the metabolic capacity, oxidative status and neurotoxicity of polychaetes after long-term exposure. The results revealed an alteration of energy-related responses in contaminated polychaetes under both salinity conditions, resulting in an increase of metabolism and expenditure of their energy reserves (lower glycogen and protein contents). Moreover, a concentration-dependent toxicity (higher lipid peroxidation, lower ratio between reduced and oxidized glutathione and activation of antioxidant defences and biotransformation mechanisms) was observed in H. diversicolor, especially when exposed to low salinity. Additionally, neurotoxicity was observed by inhibition of Cholinesterases activity in organisms exposed to MWCNTs at both salinities.
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Chen, Ke; Li, Erchao; Li, Tongyu; Xu, Chang; Wang, Xiaodan; Lin, Heizhao; Qin, Jian G.; Chen, Liqiao
2015-01-01
The Pacific white shrimp Litopenaeus vannamei is a euryhaline penaeid species that shows ontogenetic adaptations to salinity, with its larvae inhabiting oceanic environments and postlarvae and juveniles inhabiting estuaries and lagoons. Ontogenetic adaptations to salinity manifest in L. vannamei through strong hyper-osmoregulatory and hypo-osmoregulatory patterns and an ability to tolerate extremely low salinity levels. To understand this adaptive mechanism to salinity stress, RNA-seq was used to compare the transcriptomic response of L. vannamei to changes in salinity from 30 (control) to 3 practical salinity units (psu) for 8 weeks. In total, 26,034 genes were obtained from the hepatopancreas tissue of L. vannamei using the Illumina HiSeq 2000 system, and 855 genes showed significant changes in expression under salinity stress. Eighteen top Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were significantly involved in physiological responses, particularly in lipid metabolism, including fatty-acid biosynthesis, arachidonic acid metabolism and glycosphingolipid and glycosaminoglycan metabolism. Lipids or fatty acids can reduce osmotic stress in L. vannamei by providing additional energy or changing the membrane structure to allow osmoregulation in relevant organs, such as the gills. Steroid hormone biosynthesis and the phosphonate and phosphinate metabolism pathways were also involved in the adaptation of L. vannamei to low salinity, and the differential expression patterns of 20 randomly selected genes were validated by quantitative real-time PCR (qPCR). This study is the first report on the long-term adaptive transcriptomic response of L. vannamei to low salinity, and the results will further our understanding of the mechanisms underlying osmoregulation in euryhaline crustaceans. PMID:26147449
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NASA Astrophysics Data System (ADS)
Renaud, F.; Sebesvari, Z.; Nguyen, M. T.; Hagenlocher, M.
2016-12-01
The Vietnamese portion of the Mekong Delta increasingly suffers from salinity intrusion in its freshwater system, as exemplified by the historically high salinity levels recorded during the 2016 dry season. Although this exceptional situation was linked to the El Niño phenomena, many factors contribute to an increasing salinization of coastal areas. Salinity intrusion is a natural process in this tidal area but its extent is increasing and projected to worsen due to increased demand for water, diversion/storage of water flows in the Mekong river and its tributaries, land subsidence linked to groundwater over-abstraction, changes in land use and water management in coastal areas, and sea level rise. The Mekong Delta remains predominantly an agricultural landscape which contributes the majority of the rice, aquaculture, and fruit production of the country. These systems will need to be adapted to increased salinity levels. We will present results from two research projects, DeltAdapt and DELTAS, which were designed to allow understanding of, respectively (1) the main drivers of change of agro-ecosystems in coastal areas of the delta and (2) the relative vulnerabilities and risks deltaic social-ecological systems face with respect to various environmental hazards. We used the Global Delta Vulnerability Index developed within the DELTAS project to characterize the vulnerabilities and risks faced by coastal provinces of the delta with respect to salinity intrusion. The analysis allows us to understand which social, economic, and ecological variables index explain the relative vulnerability of the provinces. In addition, drivers of change (e.g. policy, economic, social, environmental) of coastal agro-ecosystems were systematically analyzed through 80 interviews and 7 focus group discussions in the provinces of Kien Giang and Soc Trang within the DeltAdapt project. This was combined with the analysis of Vietnamese policies to determine which are the important drivers of change in the region and how these contribute (or not) to the adaptation of agro-ecosystems facing increased salinity intrusion. By combining these results, we will point to potential policies that could be considered by various authorities to allow for a greater adaptability of agro-ecosystems in the coastal provinces of the region.
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Environmental impacts on the southern Florida coastal waters: a history of change in Florida Bay
Brewster-Wingard, G. L.; Ishman, S. E.; Holmes, C. W.
1998-01-01
Analyses of four cores located in the northern transitional, eastern, and central portions of Florida Bay reveal historical patterns of change in salinity and seagrass distribution. Salinity and the distribution of seagrass beds are two critical issues for the restoration of Florida Bay. The distribution of benthic fauna in Bob Allen 6A and Russell Bank 19B cores illustrates changes in environmental parameters prior to 1900. Natural fluctuations occur in salinity, but the amplitude of those fluctuations was limited to a 15–20% shift about the mean. Subtle changes occur in the benthic fauna around 1910, but beginning around 1940, the pattern of salinity fluctuation departs substantially from the pre-1900 pattern. Post-1940, the salinity oscillates 40–60% about the mean. This pattern is seen in all indicators measured. Around 1970, a significant but short term decline occurred in salinity. The Taylor Creek T24 core from the northern transitional zone reflects changes in freshwater flow that have occurred during this century. The upper portion of the core records a significant increase in salinity, with a slight decrease occurring in recent years. The Pass Key 37 core represents an area of very high sedimentation rates; an increase in salinity occurs in the upper portion of the core. Natural fluctuations in seagrass distribution are inferred from the shifts in relative abundance of epiphytal species preserved in the cores. All four cores show an increase in epiphytes and therefore in seagrass coverage during this century. An increase also occurs in epiphytal species that can dwell on either Thalassia or macro-algal mats associated with Thalassia beds. These data suggest an increase in algal-mats has occurred during this century. The Bob Allen 6A core records an extensive period during the 1800's of little to no vegetative cover of the substrate based on the near absence of epiphytic species in that segment of the core. Following this period, the epiphytal species increase rapidly in abundance, implying that vegetation may have the ability to disseminate rapidly.
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Akanda, Ali Shafqat; Jutla, Antarpreet S.; Gute, David M.; Sack, R. Bradley; Alam, Munirul; Huq, Anwar; Colwell, Rita R.; Islam, Shafiqul
2013-01-01
The highly populated floodplains of the Bengal Delta have a long history of endemic and epidemic cholera outbreaks, both coastal and inland. Previous studies have not addressed the spatio-temporal dynamics of population vulnerability related to the influence of underlying large-scale processes. We analyzed spatial and temporal variability of cholera incidence across six surveillance sites in the Bengal Delta and their association with regional hydroclimatic and environmental drivers. More specifically, we use salinity and flood inundation modeling across the vulnerable districts of Bangladesh to test earlier proposed hypotheses on the role of these environmental variables. Our results show strong influence of seasonal and interannual variability in estuarine salinity on spring outbreaks and inland flooding on fall outbreaks. A large segment of the population in the Bengal Delta floodplains remain vulnerable to these biannual cholera transmission mechanisms that provide ecologic and environmental conditions for outbreaks over large geographic regions. PMID:24019441
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[Microbial diversity of salt lakes in Badain Jaran desert].
Li, Lu; Hao, Chunbo; Wang, Lihua; Pei, Lixin
2015-04-04
We characterized procaryotic biodiversity, community structure and the relationship between the community structure and environmental factors of salt lakes in Badain Jaran desert, Inner Mongolia, China. We constructed 16S rRNA gene clone libraries by molecular biology techniques to analyze the procaryotic phylogenetic relationships, and used R language to compare the community structure of haloalkalophiles in the salt lakes. Water in this region has a high salinity ranging from 165 to 397 g/L. The water is strongly alkaline with pH value above 10. The microbial diversity and community structure of the salt lakes are obviously different. The diversity of bacteria is more abundant than that of archaea. The main categories of bacteria in the samples are Gammaproteobacteria, Bacteroidetes, Alphaproteobacteria, Firmicute and Verrucomicrobia, whereas all archaea only belong to Halobacteriaceae of Euryarchaeota. Salinity is the most important environmental factor influencing the bacterial community structure, whereas the archaea community structure was influenced comprehensively by multiple environmental factors.
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NASA Astrophysics Data System (ADS)
Giménez, Luis
2002-12-01
Chasmagnathus granulata is a South American crab occurring in estuarine salt marshes of the Brazilian, Uruguayan and Argentine coasts. Life history is characterized by an export strategy of its larval stages. I reviewed information on experimental manipulation of salinity during embryonic and larval development (pre- and posthatching salinities), and on habitat characteristics of C. granulata in order to determine potential effects of larval response to salinity in the field and to suggest consequences for the population structure. Local populations are spread over coastal areas with different physical characteristics. Benthic phases occupy estuaries characterized by different patterns of salinity variation, and release larvae to coastal waters characterized by strong salinity gradients. The zoea 1 of C. granulata showed a strong acclimatory response to low salinity. This response operated only during the first weeks of development (during zoeae 1 and 2) since subsequent larval survival at low posthatching salinities was consistently low. Larvae developing at low salinity frequently followed a developmental pathway with five instead of four zoeal stages. The ability to acclimate and the variability in larval development (i.e. the existence of alternative developmental pathways) could be interpreted as a strategy to buffer environmental variability at spatial scales of local or population networks. Early survivorship and production of larvae may be relatively high across a rather wide range of variability in salinity (5-32‰). Plastic responses to low salinity would therefore contribute to maintain a certain degree of population connectivity and persistence regardless of habitat heterogeneity.
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NASA Astrophysics Data System (ADS)
Giménez, Luis
2003-01-01
Chasmagnathus granulata is a South American crab occurring in estuarine salt marshes of the Brazilian, Uruguayan and Argentine coasts. Life history is characterized by an export strategy of its larval stages. I reviewed information on experimental manipulation of salinity during embryonic and larval development (pre- and posthatching salinities), and on habitat characteristics of C. granulata in order to determine potential effects of larval response to salinity in the field and to suggest consequences for the population structure. Local populations are spread over coastal areas with different physical characteristics. Benthic phases occupy estuaries characterized by different patterns of salinity variation, and release larvae to coastal waters characterized by strong salinity gradients. The zoea 1 of C. granulata showed a strong acclimatory response to low salinity. This response operated only during the first weeks of development (during zoeae 1 and 2) since subsequent larval survival at low posthatching salinities was consistently low. Larvae developing at low salinity frequently followed a developmental pathway with five instead of four zoeal stages. The ability to acclimate and the variability in larval development (i.e. the existence of alternative developmental pathways) could be interpreted as a strategy to buffer environmental variability at spatial scales of local or population networks. Early survivorship and production of larvae may be relatively high across a rather wide range of variability in salinity (5-32‰). Plastic responses to low salinity would therefore contribute to maintain a certain degree of population connectivity and persistence regardless of habitat heterogeneity.
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Genetic variation and plasticity of Plantago coronopus under saline conditions
NASA Astrophysics Data System (ADS)
Smekens, Marret J.; van Tienderen, Peter H.
2001-08-01
Phenotypic plasticity may allow organisms to cope with variation in the environmental conditions they encounter in their natural habitats. Salt adaptation appears to be an excellent example of such a plastic response. Many plant species accumulate organic solutes in response to saline conditions. Comparative and molecular studies suggest that this is an adaptation to osmotic stress. However, evidence relating the physiological responses to fitness parameters is rare and requires assessing the potential costs and benefits of plasticity. We studied the response of thirty families derived from plants collected in three populations of Plantago coronopus in a greenhouse experiment under saline and non-saline conditions. We indeed found a positive selection gradient for the sorbitol percentage under saline conditions: plant families with a higher proportion of sorbitol produced more spikes. No effects of sorbitol on fitness parameters were found under non-saline conditions. Populations also differed genetically in leaf number, spike number, sorbitol concentration and percentages of different soluble sugars. Salt treatment led to a reduction of vegetative biomass and spike production but increased leaf dry matter percentage and leaf thickness. Both under saline and non-saline conditions there was a negative trade-off between vegetative growth and reproduction. Families with a high plasticity in leaf thickness had a lower total spike length under non-saline conditions. This would imply that natural selection under predominantly non-saline conditions would lead to a decrease in the ability to change leaf morphology in response to exposure to salt. All other tests revealed no indication for any costs of plasticity to saline conditions.
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Phytoplankton species composition of four ecological provinces in Yellow Sea, China
NASA Astrophysics Data System (ADS)
Li, Xiaoqian; Feng, Yuanyuan; Leng, Xiaoyun; Liu, Haijiao; Sun, Jun
2017-12-01
The ecological province based on phytoplankton species composition is important to understanding the interplay between environmental parameters and phytoplankton species composition. The aim of this study was to establish phytoplankton species composition ecological pattern thus elucidate the relationship between environmental factors and the phytoplankton species composition in the ecological provinces. Phytoplankton samples were collected from 31 stations in Yellow Sea (121.00°-125.00°E, 32.00°-39.22°N) in November 2014. The samples were enumerated and identified with the Utermöhl method under an optical inverted microscope-AE2000 with magnifications of 200 × or 400 ×. In the present study, a total of 141 taxa belonging to 60 genera of 4 phyla of phytoplankton were identified, among them 101 species of 45 genera were Bacillariophyta, 36 species of 11 genera were Dinophyta, 3 species of 3 genera were Chrysophyta and 1 species of 1 genera was Chlorophyta. The study area was divided into 4 ecological provinces according to an unsupervised cluster algorithm applied to the phytoplankton biomass. A T-S (Temperature-Salinity) scatter diagram depicted with data of water temperature and salinity defined by environmental provinces matched well with the ecological provinces. The results of Canonical Correspondence Analysis (CCA) indicated that the phytoplankton species composition was mainly correlated with temperature, salinity and silicate concentration in the studied area. A method of establishing ecological provinces is useful to further understanding the environmental effects on the marine phytoplankton species composition and the consequent marine biogeochemistry.
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Yang, Jian; Jiang, Hongchen; Liu, Wen; Wang, Beichen
2018-01-01
Uncovering the limiting factors for benthic algal distributions in lakes is of great importance to understanding of their role in global carbon cycling. However, limited is known about the benthic algal community distribution and how they are influenced by geographic distance and environmental variables in alpine lakes. Here, we investigated the benthic algal community compositions in the surface sediments of six lakes on the Qinghai-Tibetan Plateau (QTP), China (salinity ranging from 0.8 to 365.6 g/L; pairwise geographic distance among the studied lakes ranging 8–514 km) employing an integrated approach including Illumina-Miseq sequencing and environmental geochemistry. The results showed that the algal communities of the studied samples were mainly composed of orders of Bacillariales, Ceramiales, Naviculales, Oscillatoriales, Spirulinales, Synechococcales, and Vaucheriales. The benthic algal community compositions in these QTP lakes were significantly (p < 0.05) correlated with many environmental (e.g., dissolved inorganic and organic carbon, illumination intensity, total nitrogen and phosphorus, turbidity and water temperature) and spatial factors, and salinity did not show significant influence on the benthic algal community structures in the studied lakes. Furthermore, geographic distance showed strong, significant correlation (r = 0.578, p < 0.001) with the benthic algal community compositions among the studied lakes, suggesting that spatial factors may play important roles in influencing the benthic algal distribution. These results expand our current knowledge on the influencing factors for the distributions of benthic alga in alpine lakes. PMID:29636745
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Piazza, Bryan P.; LaPeyre, Megan K.; Keim, B.D.
2010-01-01
Climate creates environmental constraints (filters) that affect the abundance and distribution of species. In estuaries, these constraints often result from variability in water flow properties and environmental conditions (i.e. water flow, salinity, water temperature) and can have significant effects on the abundance and distribution of commercially important nekton species. We investigated links between large-scale climate variability and juvenile brown shrimp Farfantepenaeus aztecus abundance in Breton Sound estuary, Louisiana (USA). Our goals were to (1) determine if a teleconnection exists between local juvenile brown shrimp abundance and the El Niño Southern Oscillation (ENSO) and (2) relate that linkage to environmental constraints that may affect juvenile brown shrimp recruitment to, and survival in, the estuary. Our results identified a teleconnection between winter ENSO conditions and juvenile brown shrimp abundance in Breton Sound estuary the following spring. The physical connection results from the impact of ENSO on winter weather conditions in Breton Sound (air pressure, temperature, and precipitation). Juvenile brown shrimp abundance effects lagged ENSO by 3 mo: lower than average abundances of juvenile brown shrimp were caught in springs following winter El Niño events, and higher than average abundances of brown shrimp were caught in springs following La Niña winters. Salinity was the dominant ENSO-forced environmental filter for juvenile brown shrimp. Spring salinity was cumulatively forced by winter river discharge, winter wind forcing, and spring precipitation. Thus, predicting brown shrimp abundance requires incorporating climate variability into models.
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Ontogeny influences sensitivity to climate change stressors in an endangered fish
Komoroske, L. M.; Connon, R. E.; Lindberg, J.; Cheng, B. S.; Castillo, G.; Hasenbein, M.; Fangue, N. A.
2014-01-01
Coastal ecosystems are among the most human-impacted habitats globally, and their management is often critically linked to recovery of declining native species. In the San Francisco Estuary, the Delta Smelt (Hypomesus transpacificus) is an endemic, endangered fish strongly tied to Californian conservation planning. The complex life history of Delta Smelt combined with dynamic seasonal and spatial abiotic conditions result in dissimilar environments experienced among ontogenetic stages, which may yield stage-specific susceptibility to abiotic stressors. Climate change is forecasted to increase San Francisco Estuary water temperature and salinity; therefore, understanding the influences of ontogeny and phenotypic plasticity on tolerance to these critical environmental parameters is particularly important for Delta Smelt and other San Francisco Estuary fishes. We assessed thermal and salinity limits in several ontogenetic stages and acclimation states of Delta Smelt, and paired these data with environmental data to evaluate sensitivity to climate-change stressors. Thermal tolerance decreased among successive stages, with larval fish exhibiting the highest tolerance and post-spawning adults having the lowest. Delta Smelt had limited capacity to increase tolerance through thermal acclimation, and comparisons with field temperature data revealed that juvenile tolerance limits are the closest to current environmental conditions, which may make this stage especially susceptible to future climate warming. Maximal water temperatures observed in situ exceeded tolerance limits of juveniles and adults. Although these temperature events are currently rare, if they increase in frequency as predicted, it could result in habitat loss at these locations despite other favourable conditions for Delta Smelt. In contrast, Delta Smelt tolerated salinities spanning the range of expected environmental conditions for each ontogenetic stage, but salinity did impact survival in juvenile and adult stages in exposures over acute time scales. Our results underscore the importance of considering ontogeny and phenotypic plasticity in assessing the impacts of climate change, particularly for species adapted to spatially and temporally heterogeneous environments. PMID:27293629
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Ontogeny influences sensitivity to climate change stressors in an endangered fish.
Komoroske, L M; Connon, R E; Lindberg, J; Cheng, B S; Castillo, G; Hasenbein, M; Fangue, N A
2014-01-01
Coastal ecosystems are among the most human-impacted habitats globally, and their management is often critically linked to recovery of declining native species. In the San Francisco Estuary, the Delta Smelt (Hypomesus transpacificus) is an endemic, endangered fish strongly tied to Californian conservation planning. The complex life history of Delta Smelt combined with dynamic seasonal and spatial abiotic conditions result in dissimilar environments experienced among ontogenetic stages, which may yield stage-specific susceptibility to abiotic stressors. Climate change is forecasted to increase San Francisco Estuary water temperature and salinity; therefore, understanding the influences of ontogeny and phenotypic plasticity on tolerance to these critical environmental parameters is particularly important for Delta Smelt and other San Francisco Estuary fishes. We assessed thermal and salinity limits in several ontogenetic stages and acclimation states of Delta Smelt, and paired these data with environmental data to evaluate sensitivity to climate-change stressors. Thermal tolerance decreased among successive stages, with larval fish exhibiting the highest tolerance and post-spawning adults having the lowest. Delta Smelt had limited capacity to increase tolerance through thermal acclimation, and comparisons with field temperature data revealed that juvenile tolerance limits are the closest to current environmental conditions, which may make this stage especially susceptible to future climate warming. Maximal water temperatures observed in situ exceeded tolerance limits of juveniles and adults. Although these temperature events are currently rare, if they increase in frequency as predicted, it could result in habitat loss at these locations despite other favourable conditions for Delta Smelt. In contrast, Delta Smelt tolerated salinities spanning the range of expected environmental conditions for each ontogenetic stage, but salinity did impact survival in juvenile and adult stages in exposures over acute time scales. Our results underscore the importance of considering ontogeny and phenotypic plasticity in assessing the impacts of climate change, particularly for species adapted to spatially and temporally heterogeneous environments.
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Effects of oceanic salinity on body condition in sea snakes.
Brischoux, François; Rolland, Virginie; Bonnet, Xavier; Caillaud, Matthieu; Shine, Richard
2012-08-01
Since the transition from terrestrial to marine environments poses strong osmoregulatory and energetic challenges, temporal and spatial fluctuations in oceanic salinity might influence salt and water balance (and hence, body condition) in marine tetrapods. We assessed the effects of salinity on three species of sea snakes studied by mark-recapture in coral-reef habitats in the Neo-Caledonian Lagoon. These three species include one fully aquatic hydrophiine (Emydocephalus annulatus), one primarily aquatic laticaudine (Laticauda laticaudata), and one frequently terrestrial laticaudine (Laticauda saintgironsi). We explored how oceanic salinity affected the snakes' body condition across various temporal and spatial scales relevant to each species' ecology, using linear mixed models and multimodel inference. Mean annual salinity exerted a consistent and negative effect on the body condition of all three snake species. The most terrestrial taxon (L. saintgironsi) was sensitive to salinity over a short temporal scale, corresponding to the duration of a typical marine foraging trip for this species. In contrast, links between oceanic salinity and body condition in the fully aquatic E. annulatus and the highly aquatic L. laticaudata were strongest at a long-term (annual) scale. The sophisticated salt-excreting systems of sea snakes allow them to exploit marine environments, but do not completely overcome the osmoregulatory challenges posed by oceanic conditions. Future studies could usefully explore such effects in other secondarily marine taxa such as seabirds, turtles, and marine mammals.
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NASA Astrophysics Data System (ADS)
Du Laing, G.; De Vos, R.; Vandecasteele, B.; Lesage, E.; Tack, F. M. G.; Verloo, M. G.
2008-05-01
The effect of the flood water salinity on the mobility of heavy metals was studied for intertidal sediments of the Scheldt estuary (Belgium). Soils and sediments of 4 sampling sites were flooded with water of different salinities (0.5, 2.5, and 5 g NaCl L -1). Metal concentrations were monitored in pore water and surface water. To study the potential effects of flood water salinity on metal bioavailability, duckweed ( Lemna minor) was grown in the surface water. The salinity was found to primarily enhance the mobility of Cd and its uptake by duckweed. Cadmium concentrations in pore water of soils and sediments and surrounding surface waters significantly exceeded sanitation thresholds and quality standards during flooding of initially oxidized sediments. Moreover, the effect was observed already at lower salinities of 0.5 g NaCl L -1. This implies that risks related to Cd uptake by organisms and Cd leaching to ground water are relevant when constructing flooding areas in the brackish zones of estuaries. These risks can be reduced by inducing sulphide precipitation because Cd is then immobilised as sulphide and its mobility becomes independent of flood water salinity. This could be achieved by permanently flooding the polluted sediments, because sulphates are sufficiently available in the river water of the brackish part of the estuary.
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Li, Junxia; Wang, Yanxin; Xie, Xianjun
2016-02-15
In order to identify the salinization processes and its impact on arsenic, fluoride and iodine enrichment in groundwater, hydrogeochemical and environmental isotope studies have been conducted on groundwater from the Datong basin, China. The total dissolved solid (TDS) concentrations in groundwater ranged from 451 to 8250 mg/L, and 41% of all samples were identified as moderately saline groundwater with TDS of 3000-10,000 mg/L. The results of groundwater Cl concentrations, Cl/Br molar ratio and Cl isotope composition suggest that three processes including water-rock interaction, surface saline soil flushing, and evapotranspiration result in the groundwater salinization in the study area. The relatively higher Cl/Br molar ratio in groundwater from multiple screening wells indicates the contribution of halite dissolution from saline soil flushed by vertical infiltration to the groundwater salinization. However, the results of groundwater Cl/Br molar ratio model indicate that the effect of saline soil flushing practice is limited to account for the observed salinity variation in groundwater. The plots of groundwater Cl vs. Cl/Br molar ratio, and Cl vs δ(37)Cl perform the dominant effects of evapotranspiration on groundwater salinization. Inverse geochemical modeling results show that evapotranspiration may cause approximately 66% loss of shallow groundwater to account for the observed hydrochemical pattern. Due to the redox condition fluctuation induced by irrigation activities and evapotranspiration, groundwater salinization processes have negative effects on groundwater arsenic enrichment. For groundwater iodine and fluoride enrichment, evapotranspiration partly accounts for their elevation in slightly saline water. However, too strong evapotranspiration would restrict groundwater fluoride concentration due to the limitation of fluorite solubility. Copyright © 2015. Published by Elsevier B.V.
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NASA Astrophysics Data System (ADS)
Shao, Tianyun; Li, Niu; Cheng, Yongwen; Long, Xiaohua; Shao, Hongbo; Zed, Rengel
2017-04-01
Soil salinity is one of the main environmental constraints that restrict plant growth and agricultural productivity; however, utilization of salt-affected land can bring substantial benefits. This study used an in-situ remediation method by planting Jerusalem artichoke in naturally occurring saline alkali soils with different salinity (high salinity (H, >4.0 g•salt kg-1 soil), moderate salinity (M, 2.0-4.0 g•salt kg-1 soil) and low salinity (L, 1.0-2.0 g•salt kg-1 soil) in the coastal saline zone in southeast China in comparison with the respective controls without Jerusalem artichoke planting (undisturbed soil). Soil pH and salinity increased sequentially from the rhizosphere to the bulk soil and the unplanted controls. The activity of neutral phosphatase and invertase decreased in the order L > M > H, whereas that of catalase was reverse. The minimum content of calcite, muscovite and quartz, and maximum content of chlorite and albite, were found in the control soils. Planting of Jerusalem artichoke enhanced bacterial microflora in saline alkali soil. Proteobacteria, Acidobacteria, Actinobacteria and Bacteroidetes were the dominant phyla in all samples, accounting for more than 80% of the reads. The number of Operational Taxonomic Units (OTU) in the rhizosphere soil was, respectively, 1.27, 1.02 and 1.25 times higher compared with the bulk soil, suggesting that Jerusalem artichoke played a significant role in increasing abundance and diversity of soil microbial populations. The study showed that Jerusalem artichoke could be used to improve saline alkali soil by enriching bacterial communities, enhancing the activity of phosphatase and invertase, and decreasing soil salinity.
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2010-01-01
the 1/8°climatological monthly mean temperature and salinity fields from the Generalized Digital Environmental Model ( GDEM ) climatology (NAVOCEANO...1424. Page 24 of 51 NAVOCEANO, 2003. Database description for the generalized digital environmental model ( GDEM --V) Version 3.0. OAML--DBD--72
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An Ecological System Curriculum: An Integrated MST Approach to Environmental Science Education.
ERIC Educational Resources Information Center
Leonhardt, Nina A.
This paper describes an inquiry-based, student-centered mathematics, science, and technology curriculum guide. It features activities addressing such environmental science topics as groundwater modeling, water filtration, soil permeability and porosity, water temperature and salinity, and quadrant studies. Activities are organized so that the…
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Van Thuong, K; Van Tuan, V; Li, W; Sorgeloos, P; Bossier, P; Nauwynck, H
2016-12-01
In the field, moulting and salinity drop in the water due to excessive rainfall have been mentioned to be risk factors for WSSV outbreaks. Therefore, in this study, the effect of an acute change in environmental salinity and shedding of the old cuticle shell on the susceptibility of Penaeus vannamei to WSSV was evaluated by immersion challenge. For testing the effect of abrupt salinity stress, early premoult shrimp that were acclimated to 35 g L -1 were subjected to salinities of 50 g L -1 , 35 g L -1 , 20 g L -1 , 10 g L -1 and 7 g L -1 or 5 g L -1 and simultaneously exposed to 10 5.5 SID 50 mL -1 of WSSV for 5 h, after which the salinity was brought back to 35 g L -1 . Shrimp that were transferred from 35 g L -1 to 50 g L -1 , 35 g L -1 and 20 g L -1 did not become infected with WSSV. Shrimp became infected with WSSV after an acute salinity drop from 35 g L -1 to 10 g L -1 and lower. The mortality in shrimp, subjected to a salinity change to 10 g L -1 , 7 g L -1 and 5 g L -1 , was 6.7%, 46.7% and 53.3%, respectively (P < 0.05) . For testing the effect of moulting, shrimp in early premoult, moulting and post-moult were immersed in sea water containing 10 5.5 SID 50 mL -1 of WSSV. The resulting mortality due to WSSV infection in shrimp inoculated during early premoult (0%), ecdysis (53.3%) and post-moult (26.72%) demonstrated that a significant difference exists in susceptibility of shrimp during the short moulting process (P < 0.05). The findings of this study indicate that during a drop in environmental salinity lower than 10 g L -1 and ecdysis, shrimp are at risk for a WSSV infection. These findings have important implications for WSSV control measures. © 2016 John Wiley & Sons Ltd.
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Principal processes within the estuarine salinity gradient: a review.
Telesh, Irena V; Khlebovich, Vladislav V
2010-01-01
The salinity gradient is one of the main features characteristic of any estuarine ecosystem. Within this gradient in a critical salinity range of 5-8 PSU the major biotic and abiotic processes demonstrate non-linear dynamics of change in rates and directions. In estuaries, this salinity range acts as both external ecological factor and physiological characteristics of internal environment of aquatic organisms; it divides living conditions appropriate for freshwater and marine faunas, separates invertebrate communities with different osmotic regulation types, and defines the distribution range of high taxa. In this paper, the non-linearity of biotic processes within the estuarine salinity gradient is illustrated by the data on zooplankton from the Baltic estuaries. The non-tidal Baltic Sea provides a good demonstration of the above phenomena due to gradual changes of environmental factors and relatively stable isohalines. The non-linearity concept coupled with the ecosystem approach served the basis for a new definition of an estuary proposed by the authors. Copyright 2010 Elsevier Ltd. All rights reserved.
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1986-06-01
depending upon the physiological requirements of each particular stage in its life history. Spawning occurs from spring through fall in high salinity ...developed. Carapace about Order .... ............ Decapoda 2.5 times as wide as long, moderately Infraorder .......... ... Brachyura convex and nearly...cent marine waters; salinities in nates with a final ecdysis). After excess of 20.0 ppt are required for insemination, the male continues to
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Ecological Survey Data for Environmental Considerations on the Trinity River and Tributaries, Texas.
1973-07-01
purpurascens (Sw.) DC. Marsh purslane Ludwigia alustrie (L.) Ell. Maryland senna Cassia marilandica L. Mauchia Bradburia hirtella T. & G. Maximilian...conditions in the lower river. Increases and decreases in salinity due to flow volume determine to a large extent the number of marine species likely to...which may be temporary or, in some cases, long-term inhabitants of the lower river. Seasonal fluctuations in river flow. salinity , turbidity
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Landsat-Assisted Environmental Mapping in the Arctic National Wildlife Refuge, Alaska,
1982-11-01
during storm surges, support saline -tolerant plant communities and haline soils. Mountainous terrain occurs only in a small portion of the study area...line, even the saline fibrous Histic Pergelic Crya- understood (Mackay 1963). Probably the biggest quepts and Cryohemists along the coast. questions...which due to the very unstable substrate. A few species, Cantion (1961) termed "littoral tundra," lies such as sea purslane (Honcken’a peploides), north
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Xu, Chongzhi; Tang, Xiaoli; Shao, Hongbo; Wang, Hongyan
2016-01-01
Soil salinity is becoming the key constraints factor to agricultural production. Therefore, the plant especially the crops possessing capacities of salt tolerance will be of great economic significance. The adaptation or tolerance of plant to salinity stress involves a series of physiological, metabolic and molecular mechanisms. Halophytes are the kind of organisms which acquire special salt tolerance mechanisms to respond to the salt tress and ensure normal growth and development under saline conditions in their lengthy evolutionary adaptation, so understanding how halophytes respond to salinity stress will provide us with methods and tactics to foster and develop salt resistant varieties of crops. The strategies in physiological and molecular level adopted by halophytes are various including the changes in photosynthetic and transpiration rate, the sequestration of Na+ to extracellular or vacuole, the regulation of stomata aperture and stomatal density, the accumulation and synthesis of the phytohormones as well as the relevant gene expression underlying these physiological traits, such as the stress signal transduction, the regulation of the transcription factors, the activation and expression of the transporter genes, the activation or inhibition of the synthetases and so on. This review focuses on the research advances of the regulating mechanisms in halophytes from physiological to molecular, which render the halophytes tolerance and adaption to salinity stress. PMID:27252587
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Schlatter, Karen; Grabau, Matthew R.; Shafroth, Patrick B.; Zamora-Arroyo, Francisco
2017-01-01
Drastic alterations to river hydrology, land use change, and the spread of the nonnative shrub, tamarisk (Tamarix spp.), have led to the degradation of riparian habitat in the Colorado River Delta in Mexico. Delivery of environmental flows to promote native cottonwood (Populus spp.) and willow (Salix spp.) recruitment in human-impacted riparian systems can be unsuccessful due to flow-magnitude constraints and altered abiotic–biotic feedbacks. In 2014, an experimental pulse flow of water was delivered to the Colorado River in Mexico as part of the U.S.-Mexico binational agreement, Minute 319. We conducted a field experiment to assess the effects of vegetation removal, seed augmentation, and environmental flows, separately and in combination, on germination and first-year seedling establishment of cottonwood, willow, and tamarisk at five replicate sites along 5 river km. The relatively low-magnitude flow deliveries did not substantively restore natural fluvial processes of erosion, sediment deposition, and vegetation scour, but did provide wetted surface soils, shallow groundwater, and low soil salinity. Cottonwood and willow only established in wetted, cleared treatments, and establishment was variable in these treatments due to variable site conditions and inundation duration and timing. Wetted soils, bare surface availability, soil salinity, and seed availability were significant factors contributing to successful cottonwood and willow germination, while soil salinity and texture affected seedling persistence over the growing season. Tamarisk germinated and persisted in a wider range of environmental conditions than cottonwood and willow, including in un-cleared treatment areas. Our results suggest that site management can increase cottonwood and willow recruitment success from low-magnitude environmental flow events, an approach that can be applied in other portions of the Delta and to other human-impacted riparian systems across the world with similar ecological limitations.
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Christensen, E A F; Svendsen, M B S; Steffensen, J F
2017-03-01
The present study determined the blood plasma osmolality and oxygen consumption of the perch Perca fluviatilis at different salinities (0, 10 and 15) and temperatures (5, 10 and 20° C). Blood plasma osmolality increased with salinity at all temperatures. Standard metabolic rate (SMR) increased with salinity at 10 and 20° C. Maximum metabolic rate (MMR) and aerobic scope was lowest at salinity of 15 at 5° C, yet at 20° C, they were lowest at a salinity of 0. A cost of osmoregulation (SMR at a salinity of 0 and 15 compared with SMR at a salinity of 10) could only be detected at a salinity of 15 at 20° C, where it was 28%. The results show that P. fluviatilis have capacity to osmoregulate in hyper-osmotic environments. This contradicts previous studies and indicates intraspecific variability in osmoregulatory capabilities among P. fluviatilis populations or habitat origins. An apparent cost of osmoregulation (28%) at a salinity of 15 at 20° C indicates that the cost of osmoregulation in P. fluviatilis increases with temperature under hyperosmotic conditions and a power analysis showed that the cost of osmoregulation could be lower than 12·5% under other environmental conditions. The effect of salinity on MMR is possibly due to a reduction in gill permeability, initiated to reduce osmotic stress. An interaction between salinity and temperature on aerobic scope shows that high salinity habitats are energetically beneficial during warm periods (summer), whereas low salinity habitats are energetically beneficial during cold periods (winter). It is suggested, therefore, that the seasonal migrations of P. fluviatilis between brackish and fresh water is to select an environment that is optimal for metabolism and aerobic scope. © 2016 The Fisheries Society of the British Isles.
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Modeling salt movement and halophytic crop growth on marginal lands with the APEX model
NASA Astrophysics Data System (ADS)
Goehring, N.; Saito, L.; Verburg, P.; Jeong, J.; Garrett, A.
2016-12-01
Saline soils negatively impact crop productivity in nearly 20% of irrigated agricultural lands worldwide. At these saline sites, cultivation of highly salt-tolerant plants, known as halophytes, may increase productivity compared to conventional salt-sensitive crops (i.e., glycophytes), thereby increasing the economic potential of marginal lands. Through a variety of mechanisms, halophytes are more effective than glycophytes at excluding, accumulating, and secreting salts from their tissues. Each mechanism can have a different impact on the salt balance in the plant-soil-water system. To date, little information is available to understand the long-term impacts of halophyte cultivation on environmental quality. This project utilizes the Agricultural Policy/Environmental Extender (APEX) model, developed by the US Department of Agriculture, to model the growth and production of two halophytic crops. The crops being modeled include quinoa (Chenopodium quinoa), which has utilities for human consumption and forage, and AC Saltlander green wheatgrass (Elymus hoffmannii), which has forage utility. APEX simulates salt movement between soil layers and accounts for the salt balance in the plant-soil-water system, including salinity in irrigation water and crop-specific salt uptake. Key crop growth parameters in APEX are derived from experimental growth data obtained under non-stressed conditions. Data from greenhouse and field experiments in which quinoa and AC Saltlander were grown under various soil salinity and irrigation salinity treatments are being used to parameterize, calibrate, and test the model. This presentation will discuss progress on crop parameterization and completed model runs under different salt-affected soil and irrigation conditions.
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Magnetic Resonance Imaging of Electrolysis.
Meir, Arie; Hjouj, Mohammad; Rubinsky, Liel; Rubinsky, Boris
2015-01-01
This study explores the hypothesis that Magnetic Resonance Imaging (MRI) can image the process of electrolysis by detecting pH fronts. The study has relevance to real time control of cell ablation with electrolysis. To investigate the hypothesis we compare the following MR imaging sequences: T1 weighted, T2 weighted and Proton Density (PD), with optical images acquired using pH-sensitive dyes embedded in a physiological saline agar solution phantom treated with electrolysis and discrete measurements with a pH microprobe. We further demonstrate the biological relevance of our work using a bacterial E. Coli model, grown on the phantom. The results demonstrate the ability of MRI to image electrolysis produced pH changes in a physiological saline phantom and show that these changes correlate with cell death in the E. Coli model grown on the phantom. The results are promising and invite further experimental research. PMID:25659942
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High Temperature and Salinity Enhance Soil Nitrogen Mineralization in a Tidal Freshwater Marsh
Gao, Haifeng; Bai, Junhong; He, Xinhua; Zhao, Qingqing; Lu, Qiongqiong; Wang, Junjing
2014-01-01
Soil nitrogen (N) mineralization in wetlands is sensitive to various environmental factors. To compare the effects of salinity and temperature on N mineralization, wetland soils from a tidal freshwater marsh locating in the Yellow River Delta was incubated over a 48-d anaerobic incubation period under four salinity concentrations (0, 10, 20 and 35‰) and four temperature levels (10, 20, 30 and 40°C). The results suggested that accumulated ammonium nitrogen (NH4 +-N) increased with increasing incubation time under all salinity concentrations. Higher temperatures and salinities significantly enhanced soil N mineralization except for a short-term (≈10 days) inhibiting effect found under 35‰ salinity. The incubation time, temperature, salinity and their interactions exhibited significant effects on N mineralization (P<0.001) except the interactive effect of salinity and temperature (P>0.05), while temperature exhibited the greatest effect (P<0.001). Meanwhile, N mineralization processes were simulated using both an effective accumulated temperature model and a one-pool model. Both models fit well with the simulation of soil N mineralization process in the coastal freshwater wetlands under a range of 30 to 40°C (R2 = 0.88–0.99, P<0.01). Our results indicated that an enhanced NH4 +-N release with increasing temperature and salinity deriving from the projected global warming could have profound effects on nutrient cycling in coastal wetland ecosystems. PMID:24733366
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Kirschner, Alexander K T; Zechmeister, Thomas C; Kavka, Gerhard G; Beiwl, Christian; Herzig, Alois; Mach, Robert L; Farnleitner, Andreas H
2004-12-01
Wild birds are an important nonpoint source of fecal contamination of surface waters, but their contribution to fecal pollution is mostly difficult to estimate. Thus, to evaluate the relation between feces production and input of fecal indicator bacteria (FIB) into aquatic environments by wild waterfowl, we introduced a new holistic approach for evaluating the performance of FIB in six shallow saline habitats. For this, we monitored bird abundance, fecal pellet production, and the abundance of FIB concomitantly with a set of environmental variables over a 9-month period. For estimating fecal pellet production, a new protocol of fecal pellet counting was introduced, which was called fecal taxation (FTX). We could show that, over the whole range of investigated habitats, bird abundance, FTX values, and FIB abundance were highly significantly correlated and could demonstrate the good applicability of the FTX as a meaningful surrogate parameter for recent bird abundances and fecal contamination by birds in shallow aquatic ecosystems. Presumptive enterococci (ENT) were an excellent surrogate parameter of recent fecal contamination in these saline environments for samples collected at biweekly to monthly sampling intervals while presumptive Escherichia coli and fecal coliforms (FC) were often undetectable. Significant negative correlations with salinity indicated that E. coli and FC survival was hampered by osmotic stress. Statistical analyses further revealed that fecal pollution-associated parameters represented one system component independent from other environmental variables and that, besides feces production, rainfall, total suspended solids (direct), and trophy (indirect) had significant positive effects on ENT concentrations. Our holistic approach of linking bird abundance, feces production, and FIB detection with environmental variables may serve as a powerful model for application to other aquatic ecosystems.
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Kirschner, Alexander K. T.; Zechmeister, Thomas C.; Kavka, Gerhard G.; Beiwl, Christian; Herzig, Alois; Mach, Robert L.; Farnleitner, Andreas H.
2004-01-01
Wild birds are an important nonpoint source of fecal contamination of surface waters, but their contribution to fecal pollution is mostly difficult to estimate. Thus, to evaluate the relation between feces production and input of fecal indicator bacteria (FIB) into aquatic environments by wild waterfowl, we introduced a new holistic approach for evaluating the performance of FIB in six shallow saline habitats. For this, we monitored bird abundance, fecal pellet production, and the abundance of FIB concomitantly with a set of environmental variables over a 9-month period. For estimating fecal pellet production, a new protocol of fecal pellet counting was introduced, which was called fecal taxation (FTX). We could show that, over the whole range of investigated habitats, bird abundance, FTX values, and FIB abundance were highly significantly correlated and could demonstrate the good applicability of the FTX as a meaningful surrogate parameter for recent bird abundances and fecal contamination by birds in shallow aquatic ecosystems. Presumptive enterococci (ENT) were an excellent surrogate parameter of recent fecal contamination in these saline environments for samples collected at biweekly to monthly sampling intervals while presumptive Escherichia coli and fecal coliforms (FC) were often undetectable. Significant negative correlations with salinity indicated that E. coli and FC survival was hampered by osmotic stress. Statistical analyses further revealed that fecal pollution-associated parameters represented one system component independent from other environmental variables and that, besides feces production, rainfall, total suspended solids (direct), and trophy (indirect) had significant positive effects on ENT concentrations. Our holistic approach of linking bird abundance, feces production, and FIB detection with environmental variables may serve as a powerful model for application to other aquatic ecosystems. PMID:15574941
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Scantlebury, Michael; Haim, Abraham
2012-01-01
Daily and seasonal variations in physiological characteristics of mammals can be considered adaptations to temporal habitat variables. Across different ecosystems, physiological adjustments are expected to be sensitive to different environmental signals such as changes in photoperiod, temperature or water and food availability; the relative importance of a particular signal being dependent on the ecosystem in question. Energy intake, oxygen consumption (VO2) and body temperature (Tb) daily rhythms were compared between two populations of the broad-toothed field mouse Apodemus mystacinus, one from a Mediterranean and another from a sub-Alpine ecosystem. Mice were acclimated to short-day (SD) ‘winter’ and long-day (LD) ‘summer’ photoperiods under different levels of salinity simulating osmotic challenges. Mediterranean mice had higher VO2 values than sub-Alpine mice. In addition, mice exposed to short days had higher VO2 values when given water with a high salinity compared with mice exposed to long days. By comparison, across both populations, increasing salinity resulted in a decreased Tb in SD- but not in LD-mice. Thus, SD-mice may conserve energy by decreasing Tb during (‘winter’) conditions which are expected to be cool, whereas LD-mice might do the opposite and maintain a higher Tb during (‘summer’) conditions which are expected to be warm. LD-mice behaved to reduce energy expenditure, which might be considered a useful trait during ‘summer’ conditions. Overall, increasing salinity was a clear signal for Mediterranean-mice with resultant effects on VO2 and Tb daily rhythms but had less of an effect on sub-Alpine mice, which were more responsive to changes in photoperiod. Results provide an insight into how different populations respond physiologically to various environmental challenges. PMID:23251469
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Scantlebury, Michael; Haim, Abraham
2012-01-01
Daily and seasonal variations in physiological characteristics of mammals can be considered adaptations to temporal habitat variables. Across different ecosystems, physiological adjustments are expected to be sensitive to different environmental signals such as changes in photoperiod, temperature or water and food availability; the relative importance of a particular signal being dependent on the ecosystem in question. Energy intake, oxygen consumption (VO(2)) and body temperature (T(b)) daily rhythms were compared between two populations of the broad-toothed field mouse Apodemus mystacinus, one from a Mediterranean and another from a sub-Alpine ecosystem. Mice were acclimated to short-day (SD) 'winter' and long-day (LD) 'summer' photoperiods under different levels of salinity simulating osmotic challenges. Mediterranean mice had higher VO(2) values than sub-Alpine mice. In addition, mice exposed to short days had higher VO(2) values when given water with a high salinity compared with mice exposed to long days. By comparison, across both populations, increasing salinity resulted in a decreased T(b) in SD- but not in LD-mice. Thus, SD-mice may conserve energy by decreasing T(b) during ('winter') conditions which are expected to be cool, whereas LD-mice might do the opposite and maintain a higher T(b) during ('summer') conditions which are expected to be warm. LD-mice behaved to reduce energy expenditure, which might be considered a useful trait during 'summer' conditions. Overall, increasing salinity was a clear signal for Mediterranean-mice with resultant effects on VO(2) and T(b) daily rhythms but had less of an effect on sub-Alpine mice, which were more responsive to changes in photoperiod. Results provide an insight into how different populations respond physiologically to various environmental challenges.
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Cardeñosa, Vanessa; Medrano, Evangelina; Lorenzo, Pilar; Sánchez-Guerrero, Maria Cruz; Cuevas, Francisco; Pradas, Inmaculada; Moreno-Rojas, José M
2015-11-01
Different nitrogen inputs and/or development under adverse water conditions (water stress/low quality and/or high salinity/electrical conductivity), such as those prevailing in Almeria (Mediterranean coast, south-east Spain), may affect overall fruit and vegetable quality. This study evaluated the influence of salinity and nitrogen reduction in hydroponic nutrient solution on strawberry fruit quality and nutritional compounds (Fragaria × ananassa Duch., cv. Primoris). Strawberries obtained under salinity treatments recorded the highest values for soluble solids content (SSC; all samplings); fruit taste was thus enhanced. Additionally, salinity improved fruit nutritional value, with higher contents of antioxidants compounds (first sampling). During first and second samplings, strawberries grown under N reduction and non-saline conditions showed higher values for firmness compared to fruits developed under other treatments. Regarding health-related compounds, few differences were found except for total polyphenols concentration and antioxidant activity for the first sampling, where strawberries grown under saline treatments obtained the highest values for both parameters. The use of low-quality waters, such as those found in Almeria (salinity, N9S and N5S) and low nitrogen inputs (N5, avoid environmental impact) for strawberry cultivation does not exert a negative impact on overall quality. Positive differences could be found in SSC, firmness and health-related compounds when compared against the control treatment (N9). © 2014 Society of Chemical Industry.
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Koyama, Hiroki; Mizusawa, Nanami; Hoashi, Masataka; Tan, Engkong; Yasumoto, Ko; Jimbo, Mitsuru; Ikeda, Daisuke; Yokoyama, Takehiko; Asakawa, Shuichi; Piyapattanakorn, Sanit; Watabe, Shugo
2018-06-05
Shrimps inhabiting coastal waters can survive in a wide range of salinity. However, the molecular mechanisms involved in their acclimation to different environmental salinities have remained largely unknown. In the present study, we acclimated kuruma shrimp ( Marsupenaeus japonicus ) at 1.7%, 3.4% and 4.0% salinities. After acclimating for 6, 12, 24 and 72 h, we determined free amino acid concentrations in their abdominal muscle, and performed RNA sequencing analysis on this muscle. The concentrations of free amino acids were clearly altered depending on salinity after 24 h of acclimation. Glutamine and alanine concentrations were markedly increased following the increase of salinity. In association with such changes, many genes related to amino acid metabolism changed their expression levels. In particular, the increase of the expression level of the gene encoding glutamate-ammonia ligase, which functions in glutamine metabolism, appeared to be associated with the increased glutamine concentration at high salinity. Furthermore, the increased alanine concentration at high salinity was likely associated with the decrease in the expression levels of the the gene encoding alanine-glyoxylate transaminase. Thus, there is a possibility that changes in the concentration of free amino acids for osmoregulation in kuruma shrimp are regulated by changes in the expression levels of genes related to amino acid metabolism. © 2018. Published by The Company of Biologists Ltd.
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Prymaczok, Natalia C; Pasqualino, Valeria M; Viau, Verónica E; Rodríguez, Enrique M; Medesani, Daniel A
2016-02-01
This study was aimed at determining the role of the crustacean hyperglycemic hormone (CHH) in the physiological compensation to both saline and thermal stress, in the freshwater crayfish Cherax quadricarinatus. By determining the expression of the CHH gene in the eyestalk of juvenile crayfish, we found that maximal induction of CHH was induced at high salinity (10 g/L) and low temperature (20 °C). In order to investigate the role of CHH in the physiological compensation to such stressful conditions, recombinant CHH was supplied to stressed animals. CHH-injected crayfish showed increased hemolymphatic levels of glucose, in accordance with a significant utilization of glycogen reserves from the hepatopancreas. Furthermore, CHH administration allowed stressed animals to regulate hemolymphatic sodium and potassium at more constant levels than controls. Taken together, these results suggest a relevant role of CHH in increasing the energy available intended for processes involved in the physiological compensation of C. quadricarinatus to both saline and thermal stress.
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Cooper, Ryan N; Wissel, Björn
2012-11-27
Salinity is restricting habitatability for many biota in prairie lakes due to limited physiological abilities to cope with increasing osmotic stress. Yet, it remains unclear how salinity effects vary among major taxonomic groups and what role other environmental parameters play in shaping food-web composition. To answer these questions, we sampled fish, zooplankton and littoral macroinvertebrates in 20 prairie lakes (Saskatchewan, Canada) characterized by large gradients in water chemistry and lake morphometry. We showed that salinity thresholds differed among major taxonomic groups, as most fishes were absent above salinities of 2 g L-1, while littoral macroinvertebrates were ubiquitous. Zooplankton occurred over the whole salinity range, but changed taxonomic composition as salinity increased. Subsequently, the complexity of fish community (diversity) was associated with large changes in invertebrate communities. The directional changes in invertebrate communities to smaller taxa indicated that complex fish assemblages resulted in higher predation pressure. Most likely, as the complexity of fish community decreased, controls of invertebrate assemblages shifted from predation to competition and ultimately to productivity in hypersaline lakes. Surprisingly, invertebrate predators did not thrive in the absence of fishes in these systems. Furthermore, the here identified salinity threshold for fishes was too low to be a result of osmotic stress. Hence, winterkill was likely an important factor eliminating fishes in low salinity lakes that had high productivity and shallow water depth. Ultimately, while salinity was crucial, intricate combinations of chemical and biological mechanisms also played a major role in controlling the assemblages of major taxonomic groups in prairie lakes.
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2012-01-01
Salinity is restricting habitatability for many biota in prairie lakes due to limited physiological abilities to cope with increasing osmotic stress. Yet, it remains unclear how salinity effects vary among major taxonomic groups and what role other environmental parameters play in shaping food-web composition. To answer these questions, we sampled fish, zooplankton and littoral macroinvertebrates in 20 prairie lakes (Saskatchewan, Canada) characterized by large gradients in water chemistry and lake morphometry. We showed that salinity thresholds differed among major taxonomic groups, as most fishes were absent above salinities of 2 g L-1, while littoral macroinvertebrates were ubiquitous. Zooplankton occurred over the whole salinity range, but changed taxonomic composition as salinity increased. Subsequently, the complexity of fish community (diversity) was associated with large changes in invertebrate communities. The directional changes in invertebrate communities to smaller taxa indicated that complex fish assemblages resulted in higher predation pressure. Most likely, as the complexity of fish community decreased, controls of invertebrate assemblages shifted from predation to competition and ultimately to productivity in hypersaline lakes. Surprisingly, invertebrate predators did not thrive in the absence of fishes in these systems. Furthermore, the here identified salinity threshold for fishes was too low to be a result of osmotic stress. Hence, winterkill was likely an important factor eliminating fishes in low salinity lakes that had high productivity and shallow water depth. Ultimately, while salinity was crucial, intricate combinations of chemical and biological mechanisms also played a major role in controlling the assemblages of major taxonomic groups in prairie lakes. PMID:23186395
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Numerical Model Metrics Tools in Support of Navy Operations
NASA Astrophysics Data System (ADS)
Dykes, J. D.; Fanguy, P.
2017-12-01
Increasing demands of accurate ocean forecasts that are relevant to the Navy mission decision makers demand tools that quickly provide relevant numerical model metrics to the forecasters. Increasing modelling capabilities with ever-higher resolution domains including coupled and ensemble systems as well as the increasing volume of observations and other data sources to which to compare the model output requires more tools for the forecaster to enable doing more with less. These data can be appropriately handled in a geographic information system (GIS) fused together to provide useful information and analyses, and ultimately a better understanding how the pertinent model performs based on ground truth.. Oceanographic measurements like surface elevation, profiles of temperature and salinity, and wave height can all be incorporated into a set of layers correlated to geographic information such as bathymetry and topography. In addition, an automated system that runs concurrently with the models on high performance machines matches routinely available observations to modelled values to form a database of matchups with which statistics can be calculated and displayed, to facilitate validation of forecast state and derived variables. ArcMAP, developed by Environmental Systems Research Institute, is a GIS application used by the Naval Research Laboratory (NRL) and naval operational meteorological and oceanographic centers to analyse the environment in support of a range of Navy missions. For example, acoustic propagation in the ocean is described with a three-dimensional analysis of sound speed that depends on profiles of temperature, pressure and salinity predicted by the Navy Coastal Ocean Model. The data and model output must include geo-referencing information suitable for accurately placing the data within the ArcMAP framework. NRL has developed tools that facilitate merging these geophysical data and their analyses, including intercomparisons between model predictions as well as comparison to validation data. This methodology produces new insights and facilitates identification of potential problems in ocean prediction.
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Collier, Catherine J.; Villacorta-Rath, Cecilia; van Dijk, Kor-jent; Takahashi, Miwa; Waycott, Michelle
2014-01-01
Halophytes, such as seagrasses, predominantly form habitats in coastal and estuarine areas. These habitats can be seasonally exposed to hypo-salinity events during watershed runoff exposing them to dramatic salinity shifts and osmotic shock. The manifestation of this osmotic shock on seagrass morphology and phenology was tested in three Indo-Pacific seagrass species, Halophila ovalis, Halodule uninervis and Zostera muelleri, to hypo-salinity ranging from 3 to 36 PSU at 3 PSU increments for 10 weeks. All three species had broad salinity tolerance but demonstrated a moderate hypo-salinity stress response – analogous to a stress induced morphometric response (SIMR). Shoot proliferation occurred at salinities <30 PSU, with the largest increases, up to 400% increase in shoot density, occurring at the sub-lethal salinities <15 PSU, with the specific salinity associated with peak shoot density being variable among species. Resources were not diverted away from leaf growth or shoot development to support the new shoot production. However, at sub-lethal salinities where shoots proliferated, flowering was severely reduced for H. ovalis, the only species to flower during this experiment, demonstrating a diversion of resources away from sexual reproduction to support the investment in new shoots. This SIMR response preceded mortality, which occurred at 3 PSU for H. ovalis and 6 PSU for H. uninervis, while complete mortality was not reached for Z. muelleri. This is the first study to identify a SIMR in seagrasses, being detectable due to the fine resolution of salinity treatments tested. The detection of SIMR demonstrates the need for caution in interpreting in-situ changes in shoot density as shoot proliferation could be interpreted as a healthy or positive plant response to environmental conditions, when in fact it could signal pre-mortality stress. PMID:24705377
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Wang, Minqiang; Li, Yan; Wu, Aiping; Huang, Juying
2018-01-01
Soil salinity is a common and serious environmental problem worldwide. Arbuscular mycorrhizal fungi (AMF) are considered as bio-ameliorators of soil salinity tolerance in plants. However, few studies have addressed the possible benefits of AMF inoculation for medicinal plants under saline conditions. In this study, we examined the effects of colonization with two AMF, Funneliformis mosseae and Diversispora versiformis, alone and in combination, on the growth and nutrient uptake of the medicinal plant Chrysanthemum morifolium (Hangbaiju) in a greenhouse salt stress experiment. After 6 weeks of a non-saline pretreatment, Hangbaiju plants with and without AMF were grown for five months under salinity levels that were achieved using 0, 50 and 200 mM NaCl. Root length, shoot and root dry weight, total dry weight, and root N concentration were higher in the mycorrhizal plants than in the non-mycorrhizal plants under conditions of moderate salinity, especially with D. versiformis colonization. As salinity increased, mycorrhizal colonization and mycorrhizal dependence decreased. The enhancement of root N uptake is probably the main mechanism underlying salt tolerance in mycorrhizal plants. These results suggest that the symbiotic associations between the fungus D. versiformis and C. morifolium plants may be useful in biotechnological practice. PMID:29698448
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Wang, Yanhong; Wang, Minqiang; Li, Yan; Wu, Aiping; Huang, Juying
2018-01-01
Soil salinity is a common and serious environmental problem worldwide. Arbuscular mycorrhizal fungi (AMF) are considered as bio-ameliorators of soil salinity tolerance in plants. However, few studies have addressed the possible benefits of AMF inoculation for medicinal plants under saline conditions. In this study, we examined the effects of colonization with two AMF, Funneliformis mosseae and Diversispora versiformis, alone and in combination, on the growth and nutrient uptake of the medicinal plant Chrysanthemum morifolium (Hangbaiju) in a greenhouse salt stress experiment. After 6 weeks of a non-saline pretreatment, Hangbaiju plants with and without AMF were grown for five months under salinity levels that were achieved using 0, 50 and 200 mM NaCl. Root length, shoot and root dry weight, total dry weight, and root N concentration were higher in the mycorrhizal plants than in the non-mycorrhizal plants under conditions of moderate salinity, especially with D. versiformis colonization. As salinity increased, mycorrhizal colonization and mycorrhizal dependence decreased. The enhancement of root N uptake is probably the main mechanism underlying salt tolerance in mycorrhizal plants. These results suggest that the symbiotic associations between the fungus D. versiformis and C. morifolium plants may be useful in biotechnological practice.
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Baustian, Melissa M.; Stagg, Camille L.; Perry, Carey L.; Moss, Leland C; Carruthers, Tim J.B.; Allison, Mead
2017-01-01
Salinity alterations will likely change the plant and environmental characteristics in coastal marshes thereby influencing soil carbon accumulation rates. Coastal Louisiana marshes have been historically classified as fresh, intermediate, brackish, or saline based on resident plant community and position along a salinity gradient. Short-term total carbon accumulation rates were assessed by collecting 10-cm deep soil cores at 24 sites located in marshes spanning the salinity gradient. Bulk density, total carbon content, and the short-term accretion rates obtained with feldspar horizon markers were measured to determine total carbon accumulation rates. Despite some significant differences in soil properties among marsh types, the mean total carbon accumulation rates among marsh types were not significantly different (mean ± std. err. of 190 ± 27 g TC m−2 year−1). However, regression analysis indicated that mean annual surface salinity had a significant negative relationship with total carbon accumulation rates. Based on both analyses, the coastal Louisiana total marsh area (1,433,700 ha) accumulates about 2.7 to 3.3 Tg C year−1. Changing salinities due to increasing relative sea level or resulting from restoration activities may alter carbon accumulation rates in the short term and significantly influence the global carbon cycle.
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NASA Astrophysics Data System (ADS)
El Harti, Abderrazak; Lhissou, Rachid; Chokmani, Karem; Ouzemou, Jamal-eddine; Hassouna, Mohamed; Bachaoui, El Mostafa; El Ghmari, Abderrahmene
2016-08-01
Soil salinization is major environmental issue in irrigated agricultural production. Conventional methods for salinization monitoring are time and money consuming and limited by the high spatiotemporal variability of this phenomenon. This work aims to propose a spatiotemporal monitoring method of soil salinization in the Tadla plain in central Morocco using spectral indices derived from Thematic Mapper (TM) and Operational Land Imager (OLI) data. Six Landsat TM/OLI satellite images acquired during 13 years period (2000-2013) coupled with in-situ electrical conductivity (EC) measurements were used to develop the proposed method. After radiometric and atmospheric correction of TM/OLI images, a new soil salinity index (OLI-SI) is proposed for soil EC estimation. Validation shows that this index allowed a satisfactory EC estimation in the Tadla irrigated perimeter with coefficient of determination R2 varying from 0.55 to 0.77 and a Root Mean Square Error (RMSE) ranging between 1.02 dS/m and 2.35 dS/m. The times-series of salinity maps produced over the Tadla plain using the proposed method show that salinity is decreasing in intensity and progressively increasing in spatial extent, over the 2000-2013 period. This trend resulted in a decrease in agricultural activities in the southwestern part of the perimeter, located in the hydraulic downstream.
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Ochsenkühn, Michael A.; Röthig, Till; D’Angelo, Cecilia; Wiedenmann, Jörg; Voolstra, Christian R.
2017-01-01
The endosymbiosis between Symbiodinium dinoflagellates and stony corals provides the foundation of coral reef ecosystems. The survival of these ecosystems is under threat at a global scale, and better knowledge is needed to conceive strategies for mitigating future reef loss. Environmental disturbance imposing temperature, salinity, and nutrient stress can lead to the loss of the Symbiodinium partner, causing so-called coral bleaching. Some of the most thermotolerant coral-Symbiodinium associations occur in the Persian/Arabian Gulf and the Red Sea, which also represent the most saline coral habitats. We studied whether Symbiodinium alter their metabolite content in response to high-salinity environments. We found that Symbiodinium cells exposed to high salinity produced high levels of the osmolyte 2-O-glycerol-α-d-galactopyranoside (floridoside), both in vitro and in their coral host animals, thereby increasing their capacity and, putatively, the capacity of the holobiont to cope with the effects of osmotic stress in extreme environments. Given that floridoside has been previously shown to also act as an antioxidant, this osmolyte may serve a dual function: first, to serve as a compatible organic osmolyte accumulated by Symbiodinium in response to elevated salinities and, second, to counter reactive oxygen species produced as a consequence of potential salinity and heat stress. PMID:28835914
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NASA Astrophysics Data System (ADS)
Kbaier Ben Ismail, Dhouha; Lazure, Pascal; Puillat, Ingrid
2016-10-01
In marine sciences, many fields display high variability over a large range of spatial and temporal scales, from seconds to thousands of years. The longer recorded time series, with an increasing sampling frequency, in this field are often nonlinear, nonstationary, multiscale and noisy. Their analysis faces new challenges and thus requires the implementation of adequate and specific methods. The objective of this paper is to highlight time series analysis methods already applied in econometrics, signal processing, health, etc. to the environmental marine domain, assess advantages and inconvenients and compare classical techniques with more recent ones. Temperature, turbidity and salinity are important quantities for ecosystem studies. The authors here consider the fluctuations of sea level, salinity, turbidity and temperature recorded from the MAREL Carnot system of Boulogne-sur-Mer (France), which is a moored buoy equipped with physico-chemical measuring devices, working in continuous and autonomous conditions. In order to perform adequate statistical and spectral analyses, it is necessary to know the nature of the considered time series. For this purpose, the stationarity of the series and the occurrence of unit-root are addressed with the Augmented-Dickey Fuller tests. As an example, the harmonic analysis is not relevant for temperature, turbidity and salinity due to the nonstationary condition, except for the nearly stationary sea level datasets. In order to consider the dominant frequencies associated to the dynamics, the large number of data provided by the sensors should enable the estimation of Fourier spectral analysis. Different power spectra show a complex variability and reveal an influence of environmental factors such as tides. However, the previous classical spectral analysis, namely the Blackman-Tukey method, requires not only linear and stationary data but also evenly-spaced data. Interpolating the time series introduces numerous artifacts to the data. The Lomb-Scargle algorithm is adapted to unevenly-spaced data and is used as an alternative. The limits of the method are also set out. It was found that beyond 50% of missing measures, few significant frequencies are detected, several seasonalities are no more visible, and even a whole range of high frequency disappears progressively. Furthermore, two time-frequency decomposition methods, namely wavelets and Hilbert-Huang Transformation (HHT), are applied for the analysis of the entire dataset. Using the Continuous Wavelet Transform (CWT), some properties of the time series are determined. Then, the inertial wave and several low-frequency tidal waves are identified by the application of the Empirical Mode Decomposition (EMD). Finally, EMD based Time Dependent Intrinsic Correlation (TDIC) analysis is applied to consider the correlation between two nonstationary time series.
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NASA Astrophysics Data System (ADS)
Delsman, J. R.; Hu-a-ng, K. R. M.; Vos, P. C.; de Louw, P. G. B.; Oude Essink, G. H. P.; Stuyfzand, P. J.; Bierkens, M. F. P.
2013-11-01
Management of coastal fresh groundwater reserves requires a thorough understanding of the present-day groundwater salinity distribution and its possible future development. However, coastal groundwater often still reflects a complex history of marine transgressions and regressions, and is only rarely in equilibrium with current boundary conditions. In addition, the distribution of groundwater salinity is virtually impossible to characterize satisfactorily, complicating efforts to model and predict coastal groundwater flow. A way forward may be to account for the historical development of groundwater salinity when modeling present-day coastal groundwater flow. In this paper, we construct a palaeo-hydrogeological model to simulate the evolution of groundwater salinity in the coastal area of the Netherlands throughout the Holocene. While intended as a perceptual tool, confidence in our model results is warranted by a good correspondence with a hydrochemical characterization of groundwater origin. Model results attest to the impact of groundwater density differences on coastal groundwater flow on millennial timescales and highlight their importance in shaping today's groundwater salinity distribution. Not once reaching steady-state throughout the Holocene, our results demonstrate the long-term dynamics of salinity in coastal aquifers. This stresses the importance of accounting for the historical evolution of coastal groundwater salinity when modeling present-day coastal groundwater flow, or when predicting impacts of e.g. sea level rise on coastal aquifers. Of more local importance, our findings suggest a more significant role of pre-Holocene groundwater in the present-day groundwater salinity distribution in the Netherlands than previously recognized. The implications of our results extend beyond understanding the present-day distribution of salinity, as the proven complex history of coastal groundwater also holds important clues for understanding and predicting the distribution of other societally relevant groundwater constituents.
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Reis-Santos, P.; McCormick, S.D.; Wilson, J.M.
2008-01-01
Ammocoetes of the anadromous sea lamprey Petromyzon marinus L. spend many years in freshwater before metamorphosing and migrating to sea. Metamorphosis involves the radical transformation from a substrate-dwelling, filter feeder into a free-swimming, parasitic feeder. In the present work we examined osmoregulatory differences between ammocoetes and transformers (metamorphic juveniles), and the effects of salinity acclimation. We measured the expression of key ion-transporting proteins [Na+/K+-ATPase, vacuolar (V)-type H+-ATPase and carbonic anhydrase (CA)] as well as a number of relevant blood parameters (hematocrit, [Na+] and [Cl -]). In addition, immunofluorescence microscopy was used to identify and characterize the distributions of Na+/K+-ATPase, V-type H+-ATPase and CA immunoreactive cells in the gill. Ammocoetes did not survive in the experiments with salinities greater than 10???, whereas survival in high salinity (???25-35???) increased with increased degree of metamorphosis in transformers. Plasma [Na+] and [Cl -] of ammocoetes in freshwater was lower than transformers and increased markedly at 10???. In transformers, plasma ions increased only at high salinity (>25???). Branchial Na+/K+-ATPase levels were ??? tenfold higher in transformers compared to ammocoetes and salinity did not affect expression in either group. However, branchial H +-ATPase expression showed a negative correlation with salinity in both groups. Na+/K+-ATPase immunoreactivity was strongest in transformers and associated with clusters of cells in the interlamellar spaces. H+-ATPase (B subunit) immunoreactivity was localized to epithelial cells not expressing high Na+/K+-ATPase immunoreactivity and having a similar tissue distribution as carbonic anhydrase. The results indicate that branchial Na+/K+-ATPase and salinity tolerance increase in metamorphosing lampreys, and that branchial H+-ATPase is downregulated by salinity.
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Winter, Klaus; Holtum, Joseph A.M.
2007-01-01
The relative influence of plant age and environmental stress signals in triggering a shift from C3 photosynthesis to Crassulacean acid metabolism (CAM) in the annual halophytic C3-CAM species Mesembryanthemum crystallinum was explored by continuously monitoring net CO2 exchange of whole shoots from the seedling stage until seed set. Plants exposed to high salinity (400 mm NaCl) in hydroponic culture solution or grown in saline-droughted soil acquired between 11% and 24% of their carbon via net dark CO2 uptake involving CAM. In contrast, plants grown under nonsaline, well-watered conditions were capable of completing their life cycle by operating in the C3 mode without ever exhibiting net CO2 uptake at night. These observations are not consistent with the widely expressed view that the induction of CAM by high salinity in M. crystallinum represents an acceleration of preprogrammed developmental processes. Rather, our study demonstrates that the induction of the CAM pathway for carbon acquisition in M. crystallinum is under environmental control. PMID:17056756
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Gómez, Julio; Barboza, Francisco R; Defeo, Omar
2013-10-01
Determining the existence of interconnected responses among life-history traits and identifying underlying environmental drivers are recognized as key goals for understanding the basis of phenotypic variability. We studied potentially interconnected responses among senescence, fecundity, embryos size, weight of brooding females, size at maturity and sex ratio in a semiterrestrial amphipod affected by macroscale gradients in beach morphodynamics and salinity. To this end, multiple modelling processes based on generalized additive mixed models were used to deal with the spatio-temporal structure of the data obtained at 10 beaches during 22 months. Salinity was the only nexus among life-history traits, suggesting that this physiological stressor influences the energy balance of organisms. Different salinity scenarios determined shifts in the weight of brooding females and size at maturity, having consequences in the number and size of embryos which in turn affected sex determination and sex ratio at the population level. Our work highlights the importance of analysing field data to find the variables and potential mechanisms that define concerted responses among traits, therefore defining life-history strategies.
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Winter, Klaus; Holtum, Joseph A M
2007-01-01
The relative influence of plant age and environmental stress signals in triggering a shift from C(3) photosynthesis to Crassulacean acid metabolism (CAM) in the annual halophytic C(3)-CAM species Mesembryanthemum crystallinum was explored by continuously monitoring net CO(2) exchange of whole shoots from the seedling stage until seed set. Plants exposed to high salinity (400 mm NaCl) in hydroponic culture solution or grown in saline-droughted soil acquired between 11% and 24% of their carbon via net dark CO(2) uptake involving CAM. In contrast, plants grown under nonsaline, well-watered conditions were capable of completing their life cycle by operating in the C(3) mode without ever exhibiting net CO(2) uptake at night. These observations are not consistent with the widely expressed view that the induction of CAM by high salinity in M. crystallinum represents an acceleration of preprogrammed developmental processes. Rather, our study demonstrates that the induction of the CAM pathway for carbon acquisition in M. crystallinum is under environmental control.
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Whitman, Richard L.; Nevers, Meredith B.; Przybyla-Kelly, Katarzyna; Byappanahalli, Muruleedhara N.; Sadowsky, Michael J.; Whitman, Richard L.
2011-01-01
This paper describes the environmental populations of faecal indicator bacteria, and the processes by which these populations become nonpoint sources and influence nearshore water quality. The different possible sources of these indicator bacteria are presented. These include groundwater, springs and seeps, aquatic sediments, beach sand, birds, Cladophora and plant wrack. Also discussed are the environmental factors (moisture, sunlight, temperature and salinity) influencing their survival.
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Wang, Kai; Zou, Li; Lu, Xinxin; Mou, Xiaozhen
2018-08-15
Marginal sea sediments receive organic substrates of different origins, but whether and to what extent sediment microbial communities are reflective of the different sources of organic substrates remain unclear. To address these questions, sediment samples were collected in two connected China marginal seas, i.e., Bohai Sea and Yellow Sea, and their two major tributaries (Yellow River and Liao River). Sediment bacterial community composition (BCC) was examined using 16S rRNA gene pyrosequencing. In addition, physicochemical variables that describe environmental conditions and sediment features were measured. Our results revealed that BCCs changed with salinity and organic carbon (OC) content. Members of Gaiellaceae and Comamonadaceae showed a rapid decrease as salinity and phytoplankton-derived OC increased, while Piscirickettsiaceae and Desulfobulbaceae exhibited an opposite distribution pattern. Differences of riverine vs. marginal sea sediment BCCs could be mostly explained by salinity. However, within the marginal seas, sediment BCC variations were mainly explained by OC-related variables, including terrestrial-derived fatty acids (Terr_FA), phytoplankton-derived polyunsaturated fatty acids (Phyto_PUFA), stable carbon isotopes (δ 13 C), and carbon to nitrogen ratio (C/N). In addition to environmental variables, network analysis suggested that interactions among individual bacterial taxa might be important in shaping sediment BCCs in the studied areas. Copyright © 2018 Elsevier B.V. All rights reserved.
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Liang, Yuting; Zhao, Huihui; Zhang, Xu; Zhou, Jizhong; Li, Guanghe
2014-07-15
To compare the functional gene structure and diversity of microbial communities in saline-alkali and slightly acidic oil-contaminated sites, 40 soil samples were collected from two typical oil exploration sites in North and South China and analyzed with a comprehensive functional gene array (GeoChip 3.0). The overall microbial pattern was significantly different between the two sites, and a more divergent pattern was observed in slightly acidic soils. Response ratio was calculated to compare the microbial functional genes involved in organic contaminant degradation and carbon, nitrogen, phosphorus, and sulfur cycling. The results indicated a significantly low abundance of most genes involved in organic contaminant degradation and in the cycling of nitrogen and phosphorus in saline-alkali soils. By contrast, most carbon degradation genes and all carbon fixation genes had similar abundance at both sites. Based on the relationship between the environmental variables and microbial functional structure, pH was the major factor influencing the microbial distribution pattern in the two sites. This study demonstrated that microbial functional diversity and heterogeneity in oil-contaminated environments can vary significantly in relation to local environmental conditions. The limitation of nitrogen and phosphorus and the low degradation capacity of organic contaminant should be carefully considered, particularly in most oil-exploration sites with saline-alkali soils. Copyright © 2014 Elsevier B.V. All rights reserved.
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Breeding period in the mangrove crab Goniopsis cruentata (Decapoda: Grapsidae) in Northeast Brazil.
de Lira, José Jonathas Pereira Rodrigues; Calado, Tereza Cristina dos Santos; de Araújo, Marina de Sá Leitão Câmara
2013-03-01
The brachyuran crabs are iteroparous species which present a high diversification of reproduction patterns, which may have evolved as a species-specific response to environmental conditions. Tropical species commonly present a year-round reproduction due to stable environment conditions. Goniopsis cruentata is a crab species widely distributed along the Western Atlantic, inhabiting practically every microhabitat in the mangrove ecosystem. The aim of the present study is to determine the breeding period of the crab Goniopsis cruentata in Northeastern Brazil and also to evaluate the influence of water salinity, rainfall and air and water temperature on it. A total of 71 ovigerous females, captured from August-2007 to July-2008, were used to assess the breeding period of this species. It was analyzed by the monthly proportion of ovigerous females. A correlation was applied to verify the influence of the abiotic factors on the breeding period. The present population bred seasonal-continuously with peaks in the dry period, which was not associated with monthly variations of salinity, rainfall and air and water temperatures. Therefore, according to statistical analyses, our hypothesis was refuted. However, breeding was intensified in the dry period, when salinity and temperatures were higher and rainfall was lower. We conclude that, even though breeding is not related to monthly variation of environmental factors, it occurs in periods of higher salinity and temperatures and lower rainfall.
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Khalid, Muhammad; Bilal, Muhammad; Hassani, Danial; Iqbal, Hafiz M N; Wang, Hang; Huang, Danfeng
2017-12-01
Salinity is one of the increasingly serious environmental problems worldwide for cultivating agricultural crops. The present study was aimed to ascertain the potential of beneficial soil bacterium Azospirillum brasilense to alleviate saline stress in Trifolium repens. Experimental plants (white clover) were grown from seeds and inoculated with or without A. brasilense bacterial strain supplemented with 0, 40, 80, or 120 mM NaCl into soil. The growth attributes including, shoot heights, root lengths, fresh and dry weights, leaf area and chlorophyll content were significantly enhanced in T. repens plants grown in A. brasilense inoculated soil than un-inoculated controls, particularly under elevated salinity conditions (40, 80 and 120 mM NaCl). Malondialdehyde content of leaf was recorded to be declined under saline conditions. Moreover, the K + /Na + ratio was also improved in bacterium-inoculated plants, since A. brasilense significantly reduced the root and shoot Na + level under high salty environment. Results revealed that soil inoculation with A. brasilense could significantly promote T. repens growth under both non-saline and saline environments, and this study might be extended to other vegetables and crops for the germination and growth enhancement.
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NASA Astrophysics Data System (ADS)
Welle, Paul D.; Mauter, Meagan S.
2017-09-01
This work introduces a generalizable approach for estimating the field-scale agricultural yield losses due to soil salinization. When integrated with regional data on crop yields and prices, this model provides high-resolution estimates for revenue losses over large agricultural regions. These methods account for the uncertainty inherent in model inputs derived from satellites, experimental field data, and interpreted model results. We apply this method to estimate the effect of soil salinity on agricultural outputs in California, performing the analysis with both high-resolution (i.e. field scale) and low-resolution (i.e. county-scale) data sources to highlight the importance of spatial resolution in agricultural analysis. We estimate that soil salinity reduced agricultural revenues by 3.7 billion (1.7-7.0 billion) in 2014, amounting to 8.0 million tons of lost production relative to soil salinities below the crop-specific thresholds. When using low-resolution data sources, we find that the costs of salinization are underestimated by a factor of three. These results highlight the need for high-resolution data in agro-environmental assessment as well as the challenges associated with their integration.
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NASA Astrophysics Data System (ADS)
Rowe, Christopher L.
2018-01-01
I evaluated standard metabolic rates (SMR) of hatchling northern diamondback terrapins (Malaclemys terrapin terrapin) across a range of salinities (salinity = 1.5, 4, 8, 12, and 16 psu) that they may encounter in brackish habitats such as those in the Maryland portion of the Chesapeake Bay, U.S.A. Consumption of O2 and production of CO2 by resting, unfed animals served as estimates of SMR. A peak in SMR occurred at 8 psu which corresponds closely with the salinity at which hatchling growth was previously shown to be maximized (salinity ∼ 9 psu). It appears that SMR is influenced by growth, perhaps reflecting investments in catabolic pathways that fuel anabolism. This ecophysiological information can inform environmental conservation and management activities by identifying portions of the estuary that are bioenergetically optimal for growth of hatchling terrapins. I suggest that conservation and restoration efforts to protect terrapin populations in oligo-to mesohaline habitats should prioritize protection or creation of habitats in regions where average salinity is near 8 psu and energetic investments in growth appear to be maximized.
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Evidence of euryhalinity of the Gulf corvina (Cynoscion othonopterus).
Perez-Velazquez, M; Urquidez-Bejarano, P; González-Félix, M L; Minjarez-Osorio, C
2014-01-01
The effects of environmental salinity on physiological responses, growth, and survival of the Gulf corvina, C. othonopterus, were evaluated in a 6-week completely randomized design experiment. Corvina (17.2+/-2.3 g mean initial body weight) were subjected to salinities of 5, 15, 25, and 35 ‰ and fed a commercial feed with protein and lipid contents of 46 and 14 %, respectively. Plasma osmolality increased significantly with salinity, ranging from 335.1+/-5.3 mOsm/kg in fish maintained at 5 ‰, to 354.8+/-6.8 mOsm/kg in fish kept in seawater, while a significant inverse relationship was observed between salinity and moisture content of whole fish, ranging from 73.8+/-0.7 (measured at 5 ‰) to 76.9+/-1.0 % (measured at 35 ‰). In spite of this, growth indices (final weight, weight gain, specific growth rate, condition factor, survival) were not altered, suggesting that, like other members of the family Sciaenidae, the Gulf corvina is a strong osmoregulator. The isosmotic point for this species was estimated to correspond to a salinity of 9.8 ‰. The present study represents the first set of experimental data on salinity tolerance of C. othonopterus and confirms the euryhalinity of this species.
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Germination of Spores of Astrobiologically Relevant Bacillus Species in High-Salinity Environments
NASA Astrophysics Data System (ADS)
Nagler, Katja; Julius, Christina; Moeller, Ralf
2016-07-01
In times of increasing space exploration and search for extraterrestrial life, new questions and challenges for planetary protection, aiming to avoid forward contamination of different planets or moons with terrestrial life, are emerging. Spore-forming bacteria such as Bacillus species have a high contamination potential due to their spores' extreme resistance, enabling them to withstand space conditions. Spores require liquid water for their conversion into a growing cell (i.e., spore germination and subsequent growth). If present, water on extraterrestrial planets or moons is likely to be closely associated with salts (e.g., in salty oceans or brines), thus constituting high-salinity environments. Spores of Bacillus subtilis can germinate despite very high salt concentrations, although salt stress does exert negative effects on this process. In this study, germination and metabolic reactivation ("outgrowth") of spores of five astrobiologically relevant Bacillus species (B. megaterium, B. pumilus SAFR-032, B. nealsonii, B. mojavensis, and B. vallismortis) in high salinity (≤3.6 M NaCl) were investigated. Spores of different species exhibited different germination and outgrowth capabilities in high salinity, which strongly depended on germination conditions, especially the exact composition of the medium. In this context, a new "universal" germination trigger for Bacillus spores, named KAGE (KCl, L-alanine, D-glucose, ectoine), was identified, which will be very useful for future comparative germination and outgrowth studies on different Bacillus species. Overall, this study yielded interesting new insights on salt stress effects on spore germination and points out the difficulty of predicting the potential of spores to contaminate salty environments on extraterrestrial celestial bodies.
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Zhao, Qun; Pan, Luqing; Ren, Qin; Hu, Dongxu
2015-02-01
The white shrimp Litopenaeus vannamei has been greatly impacted by low salinity stress. To gain knowledge on the immune response in L. vannamei under such stress, we investigated digital gene expression (DEG) in L. vannamei hemocytes using the deep-sequencing platform Illumina HiSeq 2000. In total, 38,155 high quality unigenes with average length 770 bp were generated; 145 and 79 genes were identified up- or down-regulated, respectively. Functional categorization and pathways of the differentially expressed genes revealed that immune signaling pathways, cellular immunity, humoral immunity, apoptosis, cellular protein synthesis, lipid transport and energy metabolism were the differentially regulated processes occurring during low salinity stress. These results will provide a resource for subsequent gene expression studies regarding environmental stress and a valuable gene information for a better understanding of immune mechanisms of L. vannamei under low salinity stress. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Suitable Environmental Ranges for Potential Coral Reef Habitats in the Tropical Ocean
Guan, Yi; Hohn, Sönke; Merico, Agostino
2015-01-01
Coral reefs are found within a limited range of environmental conditions or tolerance limits. Estimating these limits is a critical prerequisite for understanding the impacts of climate change on the biogeography of coral reefs. Here we used the diagnostic model ReefHab to determine the current environmental tolerance limits for coral reefs and the global distribution of potential coral reef habitats as a function of six factors: temperature, salinity, nitrate, phosphate, aragonite saturation state, and light. To determine these tolerance limits, we extracted maximum and minimum values of all environmental variables in corresponding locations where coral reefs are present. We found that the global, annually averaged tolerance limits for coral reefs are 21.7—29.6 °C for temperature, 28.7—40.4 psu for salinity, 4.51 μmol L-1 for nitrate, 0.63 μmol L-1 for phosphate, and 2.82 for aragonite saturation state. The averaged minimum light intensity in coral reefs is 450 μmol photons m-2 s-1. The global area of potential reef habitats calculated by the model is 330.5 × 103 km2. Compared with previous studies, the tolerance limits for temperature, salinity, and nutrients have not changed much, whereas the minimum value of aragonite saturation in coral reef waters has decreased from 3.28 to 2.82. The potential reef habitat area calculated with ReefHab is about 121×103 km2 larger than the area estimated from the charted reefs, suggesting that the growth potential of coral reefs is higher than currently observed. PMID:26030287
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Suitable environmental ranges for potential coral reef habitats in the tropical ocean.
Guan, Yi; Hohn, Sönke; Merico, Agostino
2015-01-01
Coral reefs are found within a limited range of environmental conditions or tolerance limits. Estimating these limits is a critical prerequisite for understanding the impacts of climate change on the biogeography of coral reefs. Here we used the diagnostic model ReefHab to determine the current environmental tolerance limits for coral reefs and the global distribution of potential coral reef habitats as a function of six factors: temperature, salinity, nitrate, phosphate, aragonite saturation state, and light. To determine these tolerance limits, we extracted maximum and minimum values of all environmental variables in corresponding locations where coral reefs are present. We found that the global, annually averaged tolerance limits for coral reefs are 21.7-29.6 °C for temperature, 28.7-40.4 psu for salinity, 4.51 μmol L-1 for nitrate, 0.63 μmol L-1 for phosphate, and 2.82 for aragonite saturation state. The averaged minimum light intensity in coral reefs is 450 μmol photons m-2 s-1. The global area of potential reef habitats calculated by the model is 330.5 × 103 km2. Compared with previous studies, the tolerance limits for temperature, salinity, and nutrients have not changed much, whereas the minimum value of aragonite saturation in coral reef waters has decreased from 3.28 to 2.82. The potential reef habitat area calculated with ReefHab is about 121×103 km2 larger than the area estimated from the charted reefs, suggesting that the growth potential of coral reefs is higher than currently observed.
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NASA Astrophysics Data System (ADS)
Zhang, Yuexia; Yu, Jun; Jiang, Zhibing; Wang, Qin; Wang, Hui
2015-12-01
To explore the distribution and composition of phytoplankton community and their responses to environmental changes, summer net-collected phytoplankton and physicochemical parameters in the Hangzhou Bay during 2004-2010 were investigated. A total of four phyla and 84 species were identified, including 67 diatom and 12 dinoflagellate species. The dominant species constantly consisted of the diatoms, although the dominance of dinoflagellate and cyanobacteria increased recently. Due to great spatio-temporal variations in environmental factors (salinity, suspended solids, and nutrient concentration), significant heterogeneities in community compositions among different years and subregions (inner and middle sections, and bay mouth) were found based on the analyses of multidimensional scaling and similarity. Canonical correspondence analysis showed that salinity and Si/N were the main variables associated with algal assemblage. Compared with the historical data since the 1980s, eutrophication (N, P, and N/P increased with decreasing Si/N) was exacerbated drastically. Moreover, climatic forcing and human activities resulted in a series of physical alterations, including sediment retention, temperature increase, and salinity decrease as well as reduction in water exchanges. All these changes induced obvious increases in cell density and Chl- a while decreases in species diversity and diatom-dinoflagellate ratio as well as the shifting of dominant species. Therefore, the long-term phytoplankton variations were closely related to anthropogenic and climatic perturbations in the Hangzhou Bay.
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Marine-derived fungi: diversity of enzymes and biotechnological applications
Bonugli-Santos, Rafaella C.; dos Santos Vasconcelos, Maria R.; Passarini, Michel R. Z.; Vieira, Gabriela A. L.; Lopes, Viviane C. P.; Mainardi, Pedro H.; dos Santos, Juliana A.; de Azevedo Duarte, Lidia; Otero, Igor V. R.; da Silva Yoshida, Aline M.; Feitosa, Valker A.; Pessoa, Adalberto; Sette, Lara D.
2015-01-01
The ocean is considered to be a great reservoir of biodiversity. Microbial communities in marine environments are ecologically relevant as intermediaries of energy, and play an important role in nutrient regeneration cycles as decomposers of dead and decaying organic matter. In this sense, marine-derived fungi can be considered as a source of enzymes of industrial and/or environmental interest. Fungal strains isolated from different substrates, such as invertebrates, decaying wood, seawater, sediments, and mangrove detritus, have been reported to be producers of hydrolytic and/or oxidative enzymes, with alginate lyase, amylase, cellulase, chitinase, glucosidase, inulinase, keratinase, ligninase, lipase, nuclease, phytase, protease, and xylanase being among the enzymes produced by fungi of marine origin. These enzymes present temperature and pH optima ranging from 35 to 70∘C, and 3.0 to 11.0, respectively. High-level production in bioreactors is mainly performed using submerged-state fermentation. Certain marine-derived fungal strains present enzymes with alkaline and cold-activity characteristics, and salinity is considered an important condition in screening and production processes. The adaptability of marine-derived fungi to oceanic conditions can be considered an attractive point in the field of fungal marine biotechnology. In this review, we focus on the advances in discovering enzymes from marine-derived fungi and their biotechnological relevance. PMID:25914680
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Sinha, Amit Kumar; AbdElgawad, Hamada; Zinta, Gaurav; Dasan, Antony Franklin; Rasoloniriana, Rindra; Asard, Han; Blust, Ronny; De Boeck, Gudrun
2015-01-01
Salinity fluctuation is one of the main factors affecting the overall fitness of marine fish. In addition, water borne ammonia may occur simultaneously with salinity stress. Additionally, under such stressful circumstances, fish may encounter food deprivation. The physiological and ion-osmo regulatory adaptive capacities to cope with all these stressors alone or in combination are extensively addressed in fish. To date, studies revealing the modulation of antioxidant potential as compensatory response to multiple stressors are rather lacking. Therefore, the present work evaluated the individual and combined effects of salinity challenge, ammonia toxicity and nutritional status on oxidative stress and antioxidant status in a marine teleost, European sea bass (Dicentrarchus labrax). Fish were acclimated to normal seawater (32 ppt), to brackish water (20 ppt and 10 ppt) and to hypo-saline water (2.5 ppt). Following acclimation to different salinities for two weeks, fish were exposed to high environmental ammonia (HEA, 20 mg/L representing 50% of 96h LC50 value for ammonia) for 12 h, 48 h, 84 h and 180 h, and were either fed (2% body weight) or fasted (unfed for 7 days prior to HEA exposure). Results show that in response to decreasing salinities, oxidative stress indices such as xanthine oxidase activity, levels of hydrogen peroxide (H2O2) and lipid peroxidation (malondialdehyde, MDA) increased in the hepatic tissue of fasted fish but remained unaffected in fed fish. HEA exposure at normal salinity (32 ppt) and at reduced salinities (20 ppt and 10 ppt) increased ammonia accumulation significantly (84 h-180 h) in both feeding regimes which was associated with an increment of H2O2 and MDA contents. Unlike in fasted fish, H2O2 and MDA levels in fed fish were restored to control levels (84 h-180 h); with a concomitant increase in superoxide dismutase (SOD), catalase (CAT), components of the glutathione redox cycle (reduced glutathione, glutathione peroxidase and glutathione reductase), ascorbate peroxidase (APX) activity and reduced ascorbate (ASC) content. On the contrary, fasted fish could not activate many of these protective systems and rely mainly on CAT and ASC dependent pathways as antioxidative sentinels. The present findings exemplify that in fed fish single factors and a combination of HEA exposure and reduced seawater salinities (upto 10 ppt) were insufficient to cause oxidative damage due to the highly competent antioxidant system compared to fasted fish. However, the impact of HEA exposure at a hypo-saline environment (2.5 ppt) also defied antioxidant defence system in fed fish, suggesting this combined factor is beyond the tolerance range for both feeding groups. Overall, our results indicate that the oxidative stress mediated by the experimental conditions were exacerbated during starvation, and also suggest that feed deprivation particularly at reduced seawater salinities can instigate fish more susceptible to ammonia toxicity.
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Zinta, Gaurav; Dasan, Antony Franklin; Rasoloniriana, Rindra; Asard, Han; Blust, Ronny; De Boeck, Gudrun
2015-01-01
Salinity fluctuation is one of the main factors affecting the overall fitness of marine fish. In addition, water borne ammonia may occur simultaneously with salinity stress. Additionally, under such stressful circumstances, fish may encounter food deprivation. The physiological and ion-osmo regulatory adaptive capacities to cope with all these stressors alone or in combination are extensively addressed in fish. To date, studies revealing the modulation of antioxidant potential as compensatory response to multiple stressors are rather lacking. Therefore, the present work evaluated the individual and combined effects of salinity challenge, ammonia toxicity and nutritional status on oxidative stress and antioxidant status in a marine teleost, European sea bass (Dicentrarchus labrax). Fish were acclimated to normal seawater (32 ppt), to brackish water (20 ppt and 10 ppt) and to hypo-saline water (2.5 ppt). Following acclimation to different salinities for two weeks, fish were exposed to high environmental ammonia (HEA, 20 mg/L representing 50% of 96h LC50 value for ammonia) for 12 h, 48 h, 84 h and 180 h, and were either fed (2% body weight) or fasted (unfed for 7 days prior to HEA exposure). Results show that in response to decreasing salinities, oxidative stress indices such as xanthine oxidase activity, levels of hydrogen peroxide (H2O2) and lipid peroxidation (malondialdehyde, MDA) increased in the hepatic tissue of fasted fish but remained unaffected in fed fish. HEA exposure at normal salinity (32 ppt) and at reduced salinities (20 ppt and 10 ppt) increased ammonia accumulation significantly (84 h–180 h) in both feeding regimes which was associated with an increment of H2O2 and MDA contents. Unlike in fasted fish, H2O2 and MDA levels in fed fish were restored to control levels (84 h–180 h); with a concomitant increase in superoxide dismutase (SOD), catalase (CAT), components of the glutathione redox cycle (reduced glutathione, glutathione peroxidase and glutathione reductase), ascorbate peroxidase (APX) activity and reduced ascorbate (ASC) content. On the contrary, fasted fish could not activate many of these protective systems and rely mainly on CAT and ASC dependent pathways as antioxidative sentinels. The present findings exemplify that in fed fish single factors and a combination of HEA exposure and reduced seawater salinities (upto 10 ppt) were insufficient to cause oxidative damage due to the highly competent antioxidant system compared to fasted fish. However, the impact of HEA exposure at a hypo-saline environment (2.5 ppt) also defied antioxidant defence system in fed fish, suggesting this combined factor is beyond the tolerance range for both feeding groups. Overall, our results indicate that the oxidative stress mediated by the experimental conditions were exacerbated during starvation, and also suggest that feed deprivation particularly at reduced seawater salinities can instigate fish more susceptible to ammonia toxicity. PMID:26241315
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NASA Astrophysics Data System (ADS)
Tolotti, Monica; Milan, Manuela; Boscaini, Adriano; Soja, Gerhard; Herzig, Alois
2013-04-01
The palaeolimnological reconstruction of secular evolution of Euroepan Lakes with key socio-economical relevance respect to large (climate change) and local scale (land use, tourism) environmental changes, represents one of the objectives of the project EuLakes (European Lakes Under Environmental Stressors, Supporting lake governance to mitigate the impact of climate change, Reg. N. 2CE243P3), launched in 2010 within the Central European Inititiative. The project consortium comprises lakes of different morphology and prevalent human uses, including the meso-eutrophic Lake Neusiedl, the largest Austrian lake (total area 315 km2), and the westernmost shallow (mean depth 1.2 m) steppe lake of the Euro-Asiatic continent. The volume of Lake Neusiedl can potentially change over the years, in relation with changing balance between atmospheric precipitation and lake water evapotranspiration. Changing water budget, together with high lake salinity and turbidity, have important implications over the lake ecosystem. This contribution illustrates results of the multi-proxi palaeolimnological reconstruction of ecologial changes occurred in Lake Neusiedl during the last ca. 140 years, i.e. since the end of the last "vanished-lake" stage (1865-1871). Geochemical and biological proxies anticipate the increase in lake productivity of ca. 10 years (1950s) respect to what reported in the literature. Diatom species composition indicate a biological lake recovery in the late 1980s, and suggest a second increment in lake productivity since the late 1990s, possibly in relation with the progressive increase in the nitrogen input from agriculture. Abundance of diatoms typical of brackish waters indicated no significant long-term change in lake salinity, while variations in species toleranting dessiccation confirm the vulnerability of Lake Neusiedl toward climate-driven changes in the lake water balance. This fragility is aggravated by the the semi-arid climate conditions of the catchemnt area. Biodiversity changes, pollution, agricultural and touristic over-exploitation represent further risk factors.
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Unravelling metal mobility under complex contaminant signatures.
de Souza Machado, Anderson Abel; Spencer, Kate L; Zarfl, Christiane; O'Shea, Francis T
2018-05-01
Metals are concerning pollutants in estuaries, where contamination can undergo significant remobilisation driven by physico-chemical forcing. Environmental concentrations of metals in estuarine sediments are often higher than natural backgrounds, but show no contiguity to potential sources. Thus, better understanding the metal mobility in estuaries is essential to improve identification of pollution sources and their accountability for environmental effects. This study aims to identify the key biogeochemical drivers of metal mobilisation on contaminated estuarine sediments through (1) evaluation of the potential mobilisation under controlled conditions, and (2) investigation of the relevance of metal mobilisation for in situ pollution levels in an area with multiple contaminant sources. Sediments from a saltmarsh adjacent to a coastal landfill, a marina, and a shipyard on the Thames Estuary (Essex, UK) were exposed in the laboratory (24h, N=96, 20°C) to water under various salinity, pH, and redox potential. Major cations, Fe(II), and trace metal concentrations were analysed in the leachate and sediment. Salinity, pH and redox had a significant effect on metal mobilisation (p<0.001), e.g. under certain conditions Fe(II) leaching was increased ~1000-fold. Measurements in situ of surface and subsurface sediment cores revealed that landfill proximity poorly explained metal spatial distribution. However, physicochemical parameters explained up to 97% of geochemically normalized metal concentrations in sediments. Organic matter and pH were dominant factors for most of the metal concentrations at the sediment surface. At subsurface, major cations (Ca, Na, Mg and K) were determinant predictors of metal concentrations. Applying the empirical model obtained in the laboratory to geochemical conditions of the studied saltmarsh it was possible to demonstrate that Fe mobilisation regulates the fate of this (and other) metal in that area. Thus, present results highlight the importance of metal mobility to control sediment pollution and estuarine fate of metals. Copyright © 2017 Elsevier B.V. All rights reserved.
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Strong sorption of PCBs to nanoplastics, microplastics, carbon nanotubes, and fullerenes.
Velzeboer, I; Kwadijk, C J A F; Koelmans, A A
2014-05-06
The presence of microplastic and carbon-based nanoparticles in the environment may have implications for the fate and effects of traditional hydrophobic chemicals. Here we present parameters for the sorption of 17 CB congeners to 10-180 μm sized polyethylene (micro-PE), 70 nm polystyrene (nano-PS), multiwalled carbon nanotubes (MWCNT), fullerene (C60), and a natural sediment in the environmentally relevant 10(-5)-10(-1) μg L(-1) concentration range. Effects of salinity and sediment organic matter fouling were assessed by measuring the isotherms in fresh- and seawater, with and without sediment present. Sorption to the "bulk" sorbents sediment organic matter (OM) and micro-PE occurred through linear hydrophobic partitioning with OM and micro-PE having similar sorption affinity. Sorption to MWCNT and nano-PS was nonlinear. PCB sorption to MWCNT and C60 was 3-4 orders of magnitude stronger than to OM and micro-PE. Sorption to nano-PS was 1-2 orders of magnitude stronger than to micro-PE, which was attributed to the higher aromaticity and surface-volume ratio of nano-PS. Organic matter effects varied among sorbents, with the largest OM fouling effect observed for the high surface sorbents MWCNT and nano-PS. Salinity decreased sorption for sediment and MWCNT but increased sorption for the polymers nano-PS and micro-PE. The exceptionally strong sorption of (planar) PCBs to C60, MWCNT, and nano-PS may imply increased hazards upon membrane transfer of these particles.
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Azarias Guimarães, Amanda; Florentino, Ligiane Aparecida; Alves Almeida, Kize; Lebbe, Liesbeth; Barroso Silva, Karina; Willems, Anne; de Souza Moreira, Fatima Maria
2015-09-01
The genus Bradyrhizobium stands out among nitrogen-fixing legume-nodulating bacteria because it predominates among the efficient microsymbionts of forest, forage, and green manure legume species, as well as important species of grain legumes, such as soybean, cowpea, and peanut. Therefore, the diversity of Bradyrhizobium strains is a relevant resource from environmental and economic perspectives, and strains isolated from diverse legume species and land uses in Brazilian tropical ecosystems were assessed in this study. To accomplish this, sequences of four housekeeping genes (atpD, dnaK, gyrB, and recA) were individually analysed, with the first three also being considered using multilocus sequence analysis (MLSA). The sensitivity of the strains to different antibiotics, their tolerance to different levels of salinity, and their ability to nodulate soybean plants were also measured. The phylogenetic trees based on each individual gene, and on the concatenated housekeeping genes, revealed several strain clusters separated from any currently described species. The Bradyrhizobium strains studied were generally resistant to antibiotics. All strains were able to grow at salinity levels of up to 0.5% NaCl, whereas only strains UFLA03-142, UFLA03-143, UFLA03-145, and UFLA03-146 grew in the presence of 1% NaCl. Together, the results indicated that some of the strains studied were potential novel species, indicating that the various soils and ecosystems in Brazil may harbour an as yet unknown diversity of rhizobia. Copyright © 2015 Elsevier GmbH. All rights reserved.
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Influence of increasing temperature and salinity on herbicide toxicity in estuarine phytoplankton.
DeLorenzo, Marie E; Danese, Loren E; Baird, Thomas D
2013-07-01
Ecological risk assessments are, in part, based on results of toxicity tests conducted under standard exposure conditions. Global climate change will have a wide range of effects on estuarine habitats, including potentially increasing water temperature and salinity, which may alter the risk assessment of estuarine pollutants. We examined the effects of increasing temperature and salinity on the toxicity of common herbicides (irgarol, diuron, atrazine, and ametryn) to the phytoplankton species Dunaliella tertiolecta. Static 96-h algal bioassays were conducted for each herbicide under four exposure scenarios: standard temperature and salinity (25°C, 20 ppt), standard temperature and elevated salinity (25°C, 40 ppt), elevated temperature and standard salinity (35°C, 20 ppt), and elevated temperature and elevated salinity (35°C, 40 ppt). The endpoints assessed were algal cell density at 96 h, growth rate, chlorophyll a content, lipid content, and starch content. Increasing exposure temperature reduced growth rate and 96-h cell density but increased the cellular chlorophyll and lipid concentrations of the control algae. Exposure condition did not alter starch content of control algae. Herbicides were found to decrease growth rate, 96 h cell density, and cellular chlorophyll and lipid concentrations, while starch concentrations increased with herbicide exposure. Herbicide effects under standard test conditions were then compared with those observed under elevated temperature and salinity. Herbicide effects on growth rate, cell density, and starch content were more pronounced under elevated salinity and temperature conditions. To encompass the natural variability in estuarine temperature and salinity, and to account for future changes in climate, toxicity tests should be conducted under a wider range of environmental conditions. Copyright © 2011 Wiley Periodicals, Inc.
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Uliano, E; Cataldi, M; Carella, F; Migliaccio, O; Iaccarino, D; Agnisola, C
2010-11-01
Acute stress may affect metabolism and nitrogen excretion as part of the adaptive response that allows animals to face adverse environmental changes. In the present paper the acute effects of different salinities and temperatures on routine metabolism, spontaneous activity and excretion of ammonia and urea were studied in two freshwater fish: gambusia, Gambusia affinis and zebrafish, Danio rerio, acclimated to 27 degrees C. The effects on gill morphology were also evaluated. Five salinities (0 per thousand, 10 per thousand, 20 per thousand, 30 per thousand and 35 per thousand) were tested in gambusia, while four salinities were used in zebrafish (0 per thousand, 10 per thousand, 20 per thousand and 25 per thousand). Each salinity acute stress was tested alone or in combination with an acute temperature reduction to 20 degrees C. In gambusia, both salinity and temperature acute stress strongly stimulated urea excretion. Routine oxygen consumption was barely affected by acute salinity or temperature stress, and was reduced by the combined effects of temperature and high salinity. Gills maintained their structural integrity in all stressing conditions; hyperplasia and hypertrophy of mitochondria-rich cells were observed. In zebrafish, temperature and salinity acute changes, both alone and in combination, scarcely affected any parameter tested. The major effect observed was a reduction of nitrogen excretion at 20 degrees C-25 per thousand; under these extreme conditions a significant structural disruption of gills was observed. These results confirm the high tolerance to acute salinity and temperature stress in gambusia, and demonstrate the involvement of urea excretion modulation in the stress response in this species. Copyright 2010 Elsevier Inc. All rights reserved.
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Lin, Qiuqi; Xu, Lei; Hou, Juzhi; Liu, Zhengwen; Jeppesen, Erik; Han, Bo-Ping
2017-11-01
Warming has pronounced effects on lake ecosystems, either directly by increased temperatures or indirectly by a change in salinity. We investigated the current status of zooplankton communities and trophic structure in 45 Tibetan lakes along a 2300 m altitude and a 76 g/l salinity gradient. Freshwater to hyposaline lakes mainly had three trophic levels: phytoplankton, small zooplankton and fish/Gammarus, while mesosaline to hypersaline lakes only had two: phytoplankton and large zooplankton. Zooplankton species richness declined significantly with salinity, but did not relate with temperature. Furthermore, the decline in species richness with salinity in lakes with two trophic levels was much less abrupt than in lakes with three trophic levels. The structural variation of the zooplankton community depended on the length of the food chain, and was significantly explained by salinity as the critical environmental variable. The zooplankton community shifted from dominance of copepods and small cladoceran species in the lakes with low salinity and three trophic levels to large saline filter-feeding phyllopod species in those lakes with high salinity and two trophic levels. The zooplankton to phytoplankton biomass ratio was positively related with temperature in two-trophic-level systems and vice versa in three-trophic-level systems. As the Tibetan Plateau is warming about three times faster than the global average, our results imply that warming could have a considerable impact on the structure and function of Tibetan lake ecosystems, either via indirect effects of salinization/desalinization on species richness, composition and trophic structure or through direct effects of water temperature on trophic interactions. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Urzúa, Ángel; Bascur, Miguel; Guzmán, Fabián; Urbina, Mauricio
2018-03-01
Hemigrapsus crenulatus is a key species of coastal and estuarine ecosystems in the Southeastern Pacific and New Zealand. Since the gravid females-and their embryos-develop under conditions of variable salinity, we propose that low external salinity will be met with an increase in energy expenditures in order to maintain osmoregulation; subsequently, the use of energy reserves for reproduction will be affected. In this study, we investigate in H. crenulatus whether 1) the biomass and energy content of embryos is influenced by salinity experienced during oogenesis and embryogenesis and 2) how variation in the biomass and energy content of embryos affects larval energetic condition at hatching. Here at low salinity (5PSU), egg-bearing females experienced massive and frequent egg losses, and therefore the development of their eggs during embryogenesis was not completed. In turn, at intermediate and high salinity (15 and 30PSU) embryogenesis was completed, egg development was successful, and larvae were obtained. Consistently, larvae hatched from eggs produced and incubated at high salinity (30PSU) were larger, had higher dry weight, and had increased carbon content and energy than larvae hatched from eggs produced at intermediate salinity (15PSU). From these results, it is seen that the size and biomass of early life stages of H. crenulatus can be affected by environmental salinity experienced during oogenesis and embryogenesis, and this variation can then directly affect the energetic condition of offspring at birth. Therefore, this study reveals a "cascade effect" modulated by salinity during the early ontogeny. Copyright © 2018 Elsevier Inc. All rights reserved.
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Intraguild predation may reinforce a species-environment gradient
NASA Astrophysics Data System (ADS)
MacNeil, Calum; Dick, Jaimie T. A.
2012-05-01
Species-environment gradients are ubiquitous in nature, with studies often partially explaining the replacement of species along such gradients by autecological factors such as differential physiological tolerances. However, lacking direct evidence, the majority of studies only infer some form of inter-specific interaction, often competition, as reinforcing these gradients. There is usually the further implication that environmental factors mediate asymmetries in the interaction. Recognising the lack of explicit experimental considerations of how key inter-specific interactions are modified by the environment, we chose a study system where we were able to bring the species in question into the laboratory and conduct experiments to test hypotheses about gradient-induced asymmetries in an inter-specific interaction. To this end, we tested the hypothesis that a species-salinity gradient may be reinforced by changes in the asymmetry of intraguild predation between two species of amphipod crustaceans with wide salinity tolerances. River and estuary surveys showed that Gammarus duebeni and Gammarus zaddachi have overlapping distributions, with both surviving and reproducing in salinities ranging from freshwater to fully marine. However, the former species is relatively more abundant in low salinities and the latter in higher salinities. In the laboratory, survival of both species was high in all salinities and cannibalism occurred at low frequencies. However, intraguild predation by males on moulted females was asymmetric in favour of G. duebeni at low salinities, this asymmetry completely reversing to favour G. zaddachi at higher salinities. Thus, we provide evidence that this species-environment gradient occurs due to overlapping physiological tolerances and salinity-driven shifts in the asymmetry of a key inter-specific interaction, intraguild predation.
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Reinert, T.R.; Peterson, J.T.
2008-01-01
Increased salinity in spawning and nursery grounds in the Savannah River estuary was cited as the primary cause of a 97% decrease in adult striped bass (Morone saxatilis) and a concomitant 96% decrease in striped bass egg production. Restoration efforts focused on environmental remediation and stock enhancement have resulted in restored salinity patterns and increased egg and adult abundances. However, future water needs or harbor development may preclude further recovery by reducing freshwater inflow or increasing salinity intrusion. To assess the effect of potential changes in the salinity regime, we developed models relating discharge, tidal phase, and salinity to striped bass egg and early larval survival and re-cast these in a quantitative Bayesian belief network. The model indicated that a small upstream shift (???1.67 km) in the salinity regime would have the least impact on striped bass early life history survival, whereas shifts >1.67 km would have progressively larger impacts, with a 8.33-km shift potentially reducing our estimated survival probability by >28%. Such an impact could have cumulative and long-term detrimental effects on the recovery of the Savannah River striped bass population. The available salinity data were collected during average and low flows, so our model represents some typical and some extreme conditions during a striped bass spawning season. Our model is a relatively simplistic, "first-order" attempt at evaluating potential effects of changes in the Savannah River estuarine salinity regime and points to areas of concern and potential future research. ?? 2008 Springer Science+Business Media, LLC.
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Cardona-Olarte, P.; Twilley, R.R.; Krauss, K.W.; Rivera-Monroy, V.
2006-01-01
We investigated the combined effects of salinity and hydroperiod on seedlings of Rhizophora mangle and Laguncularia racemosa grown under experimental conditions of monoculture and mixed culture by using a simulated tidal system. The objective was to test hypotheses relative to species interactions to either tidal or permanent flooding at salinities of 10 or 40 g/l. Four-month-old seedlings were experimentally manipulated under these environmental conditions in two types of species interactions: (1) seedlings of the same species were grown separately in containers from September 2000 to August 2001 to evaluate intraspecific response and (2) seedlings of each species were mixed in containers to evaluate interspecific, competitive responses from August 2002 to April 2003. Overall, L. racemosa was strongly sensitive to treatment combinations while R. mangle showed little effect. Most plant responses of L. racemosa were affected by both salinity and hydroperiod, with hydroperiod inducing more effects than salinity. Compared to R. mangle, L. racemosa in all treatment combinations had higher relative growth rate, leaf area ratio, specific leaf area, stem elongation, total length of branches, net primary production, and stem height. Rhizophora mangle had higher biomass allocation to roots. Species growth differentiation was more pronounced at low salinity, with few species differences at high salinity under permanent flooding. These results suggest that under low to mild stress by hydroperiod and salinity, L. racemosa exhibits responses that favor its competitive dominance over R. mangle. This advantage, however, is strongly reduced as stress from salinity and hydroperiod increase. ?? Springer 2006.
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Guo, Xing-Pan; Lu, Da-Pei; Niu, Zuo-Shun; Feng, Jing-Nan; Chen, Yu-Ru; Tou, Fei-Yun; Liu, Min; Yang, Yi
2018-01-01
This study was designed to investigate the characteristics of bacterial communities in intertidal sediments along the Yangtze Estuary and their responses to environmental factors. The results showed that bacterial abundance was significantly correlated with salinity, SO 4 2- and total organic carbon, while bacterial diversity was significantly correlated with SO 4 2- and total nitrogen. At different taxonomic levels, both the dominant taxa and their abundances varied among the eight samples, with Proteobacteria being the most dominant phylum in general. Cluster analysis revealed that the bacterial community structure was influenced by river runoff and sewerage discharge. Moreover, SO 4 2- , salinity and total phosphorus were the vital environmental factors that influenced the bacterial community structure. Quantitative PCR and sequencing of sulphate-reducing bacteria indicated that the sulphate reduction process occurs frequently in intertidal sediments. These findings are important to understand the microbial ecology and biogeochemical cycles in estuarine environments. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Zhang, Yong; Shen, Ji; van der Gast, Christopher; Hahn, Martin W.; Wu, Qinglong
2011-01-01
It is widely accepted that biodiversity is lower in more extreme environments. In this study, we sought to determine whether this trend, well documented for macroorganisms, also holds at the microbial level for bacteria. We used denaturing gradient gel electrophoresis (DGGE) with phylum-specific primers to quantify the taxon richness (i.e., the DGGE band numbers) of the bacterioplankton communities of 32 pristine Tibetan lakes that represent a broad salinity range (freshwater to hypersaline). For the lakes investigated, salinity was found to be the environmental variable with the strongest influence on the bacterial community composition. We found that the bacterial taxon richness in freshwater habitats increased with increasing salinity up to a value of 1‰. In saline systems (systems with >1‰ salinity), the expected decrease of taxon richness along a gradient of further increasing salinity was not observed. These patterns were consistently observed for two sets of samples taken in two different years. A comparison of 16S rRNA gene clone libraries revealed that the bacterial community of the lake with the highest salinity was characterized by a higher recent accelerated diversification than the community of a freshwater lake, whereas the phylogenetic diversity in the hypersaline lake was lower than that in the freshwater lake. These results suggest that different evolutionary forces may act on bacterial populations in freshwater and hypersaline lakes on the Tibetan Plateau, potentially resulting in different community structures and diversity patterns. PMID:22125616
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Filker, Sabine; Forster, Dominik; Weinisch, Lea; Mora-Ruiz, Merit; González, Bernardo; Farías, María Eugenia; Rosselló-Móra, Ramon; Stoeck, Thorsten
2017-08-01
The identification of environmental barriers which govern species distribution is a fundamental concern in ecology. Even though salt was previously identified as a major transition boundary for micro- and macroorganisms alike, the salinities causing species turnover in protistan communities are unknown. We investigated 4.5 million high-quality protistan metabarcodes (V4 region of the SSU rDNA) obtained from 24 shallow salt ponds (salinities 4%-44%) from South America and Europe. Statistical analyses of protistan community profiles identified four salinity classes, which strongly selected for different protistan communities: 4-9%, 14-24%, 27-36% and 38-44%. The proportion of organisms unknown to science is highest in the 14-24% salinity class, showing that environments within this salinity range are an unappreciated reservoir of as yet undiscovered organisms. Distinct higher-rank taxon groups dominated in the four salinity classes in terms of diversity. As increasing salinities require different cellular responses to cope with salt, our results suggest that different evolutionary lineages of protists have evolved distinct haloadaptation strategies. Salinity appears to be a stronger selection factor for the structuring of protistan communities than geography. Yet, we find a higher degree of endemism in shallow salt ponds compared with less isolated ecosystems such as the open ocean. Thus, rules for biogeographic structuring of protistan communities are not universal, but depend on the ecosystem under consideration. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.
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Van Meulebroek, Lieven; Hanssens, Jochen; Steppe, Kathy; Vanhaecke, Lynn
2016-01-01
As the presence of health-promoting substances has become a significant aspect of tomato fruit appreciation, this study investigated nutrient solution salinity as a tool to enhance carotenoid accumulation in cherry tomato fruit (Solanum lycopersicum L. cv. Juanita). Hereby, a key objective was to uncover the underlying mechanisms of carotenoid metabolism, moving away from typical black box research strategies. To this end, a greenhouse experiment with five salinity treatments (ranging from 2.0 to 5.0 decisiemens (dS) m−1) was carried out and a metabolomic fingerprinting approach was applied to obtain valuable insights on the complicated interactions between salinity treatments, environmental conditions, and the plant’s genetic background. Hereby, several hundreds of metabolites were attributed a role in the plant’s salinity response (at the fruit level), whereby the overall impact turned out to be highly depending on the developmental stage. In addition, 46 of these metabolites embraced a dual significance as they were ascribed a prominent role in carotenoid metabolism as well. Based on the specific mediating actions of the retained metabolites, it could be determined that altered salinity had only marginal potential to enhance carotenoid accumulation in the concerned tomato fruit cultivar. This study invigorates the usefulness of metabolomics in modern agriculture, for instance in modeling tomato fruit quality. Moreover, the metabolome changes that were caused by the different salinity levels may enclose valuable information towards other salinity-related plant processes as well. PMID:27240343
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Muraeva, O A; Maltseva, A L; Mikhailova, N A; Granovitch, A I
2015-01-01
Salinity is one of the most important abiotic environmental factors affecting marine animals. If salinity deviate from optimum, adaptive mechanisms switch on to maintain organism's physiological activity. In this study, the reaction of the snails Littorina saxatilis from natural habitats and in response to experimental salinity decreasing was analyzed on proteomic level. The isolation of all snails inside their shells and gradually declining mortality was observed under acute experimental salinity decrease (down to 10 per hundred). Proteomic changes were evaluated in the surviving experimental mollusks compared to control individual using differential 2D gel-electrophoresis (DIGE) and subsequent LC-MS/MS-identification of proteins. Approximately 10% of analyzed proteins underwent up- or down regulation during the experiment. Proteins of folding, antioxidant response, intercellular matrix, cell adhesion, cell signaling and metabolic enzymes were identified among them. Proteome changes observed in experimental hypoosmotic stress partially reproduced in the proteomes of mollusks that live in conditions of natural freshening (estuaries). Possible mechanisms involved in the adaptation process of L. saxatilis individuals to hypo-osmotic stress are discussed.
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Yang, Jian; Jiang, Hongchen; Dong, Hailiang; Hou, Weiguo; Li, Gaoyuan; Wu, Geng
2015-01-01
Integration of DNA derived from ancient phototrophs with their characteristic lipid biomarkers has been successfully employed to reconstruct paleoenvironmental conditions. However, it is poorly known that whether the DNA and lipids of microbial functional aerobes (such as ammonia-oxidizing archaea: AOA) can be used for reconstructing past environmental conditions. Here we identify and quantify the AOA amoA genes (encoding the alpha subunit of ammonia monooxygenases) preserved in a 5.8-m sediment core (spanning the last 18,500 years) from Qinghai Lake. Parallel analyses revealed that low amoA gene abundance corresponded to high total organic carbon (TOC) and salinity, while high amoA gene abundance corresponded to low TOC and salinity. In the Qinghai Lake region, TOC can serve as an indicator of paleo-productivity and paleo-precipitation, which is related to historic nutrient input and salinity. So our data suggest that temporal variation of AOA amoA gene abundance preserved in Qinghai Lake sediment may reflect the variations of nutrient level and salinity throughout the late Pleistocene and Holocene in the Qinghai Lake region. PMID:26666501
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Identifying change in spatial accumulation of soil salinity in an inland river watershed, China.
Wang, Yugang; Deng, Caiyun; Liu, Yan; Niu, Ziru; Li, Yan
2018-04-15
Soil salinity accumulation is strong in arid areas and it has become a serious environmental problem. Knowledge of the process and spatial changes of accumulated salinity in soil can provide an insight into the spatial patterns of soil salinity accumulation. This is especially useful for estimating the spatial transport of soil salinity at the watershed scale. This study aimed to identify spatial patterns of salt accumulation in the top 20cm soils in a typical inland watershed, the Sangong River watershed in arid northwest China, using geostatistics, spatial analysis technology and the Lorenz curve. The results showed that: (1) soil salt content had great spatial variability (coefficient variation >1.0) in both in 1982 and 2015, and about 56% of the studied area experienced transition the degree of soil salt content from one class to another during 1982-2015. (2) Lorenz curves describing the proportions of soil salinity accumulation (SSA) identified that the boundary between soil salinity migration and accumulation regions was 24.3m lower in 2015 than in 1982, suggesting a spatio-temporal inequality in loading of the soil salinity transport region, indicating significant migration of soil salinity from the upstream to the downstream watershed. (3) Regardless of migration or accumulation region, the mean value of SSA per unit area was 0.17kg/m 2 higher in 2015 than 1982 (p<0.01) and the increasing SSA per unit area in irrigated land significantly increased by 0.19kg/m 2 compared with the migration region. Dramatic accumulation of soil salinity in all land use types was clearly increased by 0.29kg/m 2 in this agricultural watershed during the studied period in the arid northwest of China. This study demonstrates the spatial patterns of soil salinity accumulation, which is particularly useful for estimating the spatial transport of soil salinity at the watershed scale. Copyright © 2017 Elsevier B.V. All rights reserved.
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Lavado, Ramon; Aparicio-Fabre, Rosaura; Schlenk, Daniel
2013-01-01
Phase I biotransformation enzymes are critically important in the disposition of xenobiotics within biota and are regulated by multiple environmental cues, particularly in anadromous fish species. Given the importance of these enzyme systems in xenobiotic/endogenous chemical bioactivation and detoxification, the current study was designed to better characterize the expression of Phase I biotransformation enzymes in coho salmon (Oncorhynchus kisutch) and the effects of salinity acclimation on those enzymes. Livers, gills and olfactory tissues were collected from coho salmon (Oncorhynchus kisutch) after they had undergone acclimation from freshwater to various salinity regimes of seawater (8, 16 and 32 g/L). Using immunoblot techniques coupled with testosterone hydroxylase catalytic activities, 4 orthologs of cytochrome P450 (CYP1A, CYP2K1, CYP2M1 and CYP3A27) were measured in each tissue. Also the expression of 2 transcripts of flavin-containing monooxygenases (FMO A and B) and associated activities were measured. With the exception of CYP1A, which was down-regulated in liver, protein expression of the other 3 enzymes was induced at higher salinity, with the greatest increase observed in CYP2M1 from olfactory tissues. In liver and gills, 6 - and 16 -hydroxylation of testosterone was also significantly increased after hypersaline acclimation. Similarly, FMO A was up-regulated in all 3 tissues in a salinity-dependent pattern, whereas FMO B mRNA was down-regulated. FMO-catalyzed benzydamine N-oxygenase and methyl p-tolyl sulfoxidation were significantly induced in liver and gills by hypersalinity, but was either unchanged or not detected in olfactory tissues. These data demonstrate thatenvironmental conditions may significantly alter the toxicity of environmental chemicals in salmon during freshwater/saltwater acclimation. PMID:23925894
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Swan, Brandon K; Ehrhardt, Christopher J; Reifel, Kristen M; Moreno, Lilliana I; Valentine, David L
2010-02-01
Sulfidic, anoxic sediments of the moderately hypersaline Salton Sea contain gradients in salinity and carbon that potentially structure the sedimentary microbial community. We investigated the abundance, community structure, and diversity of Bacteria and Archaea along these gradients to further distinguish the ecologies of these domains outside their established physiological range. Quantitative PCR was used to enumerate 16S rRNA gene abundances of Bacteria, Archaea, and Crenarchaeota. Community structure and diversity were evaluated by terminal restriction fragment length polymorphism (T-RFLP), quantitative analysis of gene (16S rRNA) frequencies of dominant microorganisms, and cloning and sequencing of 16S rRNA. Archaea were numerically dominant at all depths and exhibited a lesser response to environmental gradients than that of Bacteria. The relative abundance of Crenarchaeota was low (0.4 to 22%) at all depths but increased with decreased carbon content and increased salinity. Salinity structured the bacterial community but exerted no significant control on archaeal community structure, which was weakly correlated with total carbon. Partial sequencing of archaeal 16S rRNA genes retrieved from three sediment depths revealed diverse communities of Euryarchaeota and Crenarchaeota, many of which were affiliated with groups previously described from marine sediments. The abundance of these groups across all depths suggests that many putative marine archaeal groups can tolerate elevated salinity (5.0 to 11.8% [wt/vol]) and persist under the anaerobic conditions present in Salton Sea sediments. The differential response of archaeal and bacterial communities to salinity and carbon patterns is consistent with the hypothesis that adaptations to energy stress and availability distinguish the ecologies of these domains.
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Mimouni, Hajer; Wasti, Salma; Manaa, Arafet; Gharbi, Emna; Chalh, Abdellah; Vandoorne, Bertrand; Lutts, Stanley; Ben Ahmed, Hela
2016-03-01
Environmental stresses such as salinity directly impact crop growth, and by extension, world food supply and societal prosperity. It is estimated that over 800 million hectares of land throughout the world are salt-affected. In arid and semi-arid regions, salt concentration can be close to that in the seawater. Hence, there are intensive efforts to improve plant tolerance to salinity and other environmental stressors. Salicylic acid (SA) is an important signal molecule for modulating plant responses to stress. In the present study, we examined, on multiple plant growth related endpoints, whether SA applied through the rooting medium could mitigate the adverse effects of salinity on tomato (Solanum lycopersicum) cv. Marmande. The latter is a hitherto understudied tomato plant from the above perspective; it is a classic variety that produces the large ribbed tomatoes in the Mediterranean and consumed worldwide. We found salt stress negatively affected the growth of cv. Marmande tomato plants. However, the SA-treated plants had greater shoot and root dry mass, leaf area compared to untreated plants when exposed to salt stress. Application of SA restores photosynthetic rates and photosynthetic pigment levels under salt (NaCl) exposure. Leaf water, osmotic potential, stomatal conductance transpiration rate, and biochemical parameters were also ameliorated in SA-treated plants under saline stress conditions. Overall, these data illustrate that SA increases cv. Marmande tomato growth by improving photosynthesis, regulation and balance of osmotic potential, induction of compatible osmolyte metabolism, and alleviating membrane damage. We suggest salicylic acid might be considered as a potential growth regulator to improve tomato plant salinity stress resistance, in the current era of global climate change.
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Carbonell, J A; Bilton, D T; Calosi, P; Millán, A; Stewart, A; Velasco, J
2017-04-01
Ongoing climate change is driving dramatic range shifts in diverse taxa worldwide, and species responses to global change are likely to be determined largely by population responses at geographical range margins. Here we investigate the metabolic and reproductive plasticity in response to water temperature and salinity variation of two populations of the eurythermic saline water bug Sigara selecta: one population located close to the northern edge of its distribution, in a relatively cold, thermally stable region (SE England - 'marginal'), and one close to the range centre, in a warmer and more thermally variable Mediterranean climate (SE Spain - 'core'). We compared metabolic and oviposition rates and egg size, following exposure to one of four different combinations of temperature (15 and 25°C) and salinity (10 and 35gL -1 ). Oviposition rate was significantly higher in the marginal population, although eggs laid were smaller overall. No significant differences in oxygen consumption rates were found between core and marginal populations, although the marginal population showed higher levels of plasticity in both metabolic and reproductive traits. Our results suggest that population-specific responses to environmental change are complex and may be mediated by differences in phenotypic plasticity. In S. selecta, the higher plasticity of the marginal population may facilitate both its persistence in current habitats and northward expansion with future climatic warming. The less plastic core population may be able to buffer current environmental variability with minor changes in metabolism and fecundity, but could be prone to extinction if temperature and salinity changes exceed physiological tolerance limits in the future. Copyright © 2016 Elsevier Ltd. All rights reserved.
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1989-12-01
staged by examining the California (Talent 1982). pleopod tips (P. Reilly, pcrs. comm.). The specific hormonal mechanisms that control molting cycles...Coos Bay, Oregon, was correlated California, they sometimes occur near the cooling water with changes in salinity ; because red rock crabs are...discharges of coastal power plants. Adams (1970) osmoconformers, survival was low at salinities below observed both juvenile and adult brown rock crabs in the
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Chaturvedi, L.; Keyes, C.G. Jr.; Swanberg, C.A.
The water requirements and availability for New Mexico are described. The possibility of using geothermal resources for desalination of the state's saline water sources is discussed. The following aspects of the problem are covered: resource evaluation, geothermal desalination technology, potential geothermal desalination sites, saline and geothermal aquifer well fields design, geothermal desalination plant waste brine disposal, process water pumping and brine disposal unit costs, environmental considerations, and legal and institutional considerations. (MHR)
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2003-06-01
bed. This clay layer restricts the downward migration of pollutants and restricts saline water from Choctawhatchee Bay and the Gulf of Mexico from...Because it is saline , the Lower Limestone unit is not used as a water source (U.S. Air Force, 1995). Groundwater storage and movement in the Upper... purslane , among others. Inland from the produne zone is the “scrub” zone. Vegetation found in this zone is usually stunted and wind/salt sprayed
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1984-10-01
in salinities associated with the deepening will result in subtle shifts in habita - primarily in the oligo- to mesohaline section of the James River...Institute of Marine Science for their advice on species habitat ranges. Gail Mackiernan of the Environmental Protection Agency and Steven Stegner of the...animals, mainly invertebrates , that live on the surface of or within the substrate. Some species are benthic oriented but are capable of much movement
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USGS Research on Saline Waters Co-Produced with Energy Resources
,
1997-01-01
The United States energy industry faces the challenge of satisfying our expanding thirst for energy while protecting the environment. This challenge is magnified by the increasing volumes of saline water produced with oil and gas in the Nation's aging petroleum fields. Ultimately, energy-producing companies are responsible for disposing of these waters. USGS research provides basic information, for use by regulators, industry, and the public, about the chemistry of co-produced waters and environmentally acceptable ways of handling them.
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Forcing mechanisms and hydrodynamics in Loch Linnhe, a dynamically wide Scottish estuary
NASA Astrophysics Data System (ADS)
Rabe, Berit; Hindson, Jennifer
2017-09-01
Hydrodynamic conditions in Loch Linnhe, a dynamifcally wide estuary on the west coast of Scotland, are primarily influenced by wind forcing, freshwater input, and tides. Winds in the region are orographically steered along the axis of the estuary due to surrounding mountains. A large rainfall catchment area results in a large freshwater inflow into Loch Linnhe which in turn produces low salinity waters at the head of the estuary. This, combined with a connection to the open sea with coastal salinities, leads to salinity gradients in the horizontal and vertical. Even though a range of observational programmes have focussed on Loch Linnhe, the literature still lacks an evaluation of its physical dynamics. Here we present a first description of the hydrodynamics in Loch Linnhe based on observations. Wind stress predominantly influences the surface layer, especially at low frequencies and with a stronger influence than tides during neap tides. The buoyancy-driven flow due to the large river runoff influences the circulation independent of wind stress. Seasonal (spring, autumn) and interannual (2011, 2012) variability of water masses occur especially in the surface layer. Tides are dominated by the semi-diurnal constituent M2 with tidal ellipses aligned in the along-estuary direction and a stronger influence during spring tides compared to wind. An evaluation of dimensionless numbers reveal laterally and vertically sheared exchange flows. Compared to other Scottish estuaries Loch Linnhe is wide enough to be influenced by the Earth's rotation and demonstrates an enhanced freshwater outflow along its north-western coast as the freshwater is diverted to the right in the direction of the flow. These observed patterns are important for the sustainable environmental management of this socio-economically valuable region, e.g. through their relevance to aquaculture pathogen transmission patterns. A thorough understanding of the dynamics of the system is essential for a successful evidence-based marine planning framework.
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Impact of Groundwater Salinity on Bioremediation Enhanced by Micro-Nano Bubbles
Li, Hengzhen; Hu, Liming; Xia, Zhiran
2013-01-01
Micro-nano bubbles (MNBs) technology has shown great potential in groundwater bioremediation because of their large specific surface area, negatively charged surface, long stagnation, high oxygen transfer efficiency, etc. Groundwater salinity, which varies from sites due to different geological and environmental conditions, has a strong impact on the bioremediation effect. However, the groundwater salinity effect on MNBs’ behavior has not been reported. In this study, the size distribution, oxygen transfer efficiency and zeta potential of MNBs was investigated in different salt concentrations. In addition, the permeability of MNBs’ water through sand in different salt concentrations was studied. The results showed that water salinity has no influence on bubble size distribution during MNBs generation. MNBs could greatly enhance the oxygen transfer efficiency from inner bubbles to outer water, which may greatly enhance aerobic bioremediation. However, the enhancement varied depending on salt concentration. 0.7 g/L was found to be the optimal salt concentration to transfer oxygen. Moreover, MNBs in water salinity of 0.7 g/L had the minimum zeta potential. The correlation of zeta potential and mass transfer was discussed. The hydraulic conductivities of sand were similar for MNBs water with different salt concentrations. The results suggested that salinity had a great influence on MNBs performance, and groundwater salinity should be taken into careful consideration in applying MNBs technology to the enhancement of bioremediation. PMID:28788299
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Bistability of mangrove forests and competition with freshwater plants
Jiang, Jiang; Fuller, Douglas O; Teh, Su Yean; Zhai, Lu; Koh, Hock Lye; DeAngelis, Donald L.; Sternberg, L.D.S.L.
2015-01-01
Halophytic communities such as mangrove forests and buttonwood hammocks tend to border freshwater plant communities as sharp ecotones. Most studies attribute this purely to underlying physical templates, such as groundwater salinity gradients caused by tidal flux and topography. However, a few recent studies hypothesize that self-reinforcing feedback between vegetation and vadose zone salinity are also involved and create a bistable situation in which either halophytic dominated habitat or freshwater plant communities may dominate as alternative stable states. Here, we revisit the bistability hypothesis and demonstrate the mechanisms that result in bistability. We demonstrate with remote sensing imagery the sharp boundaries between freshwater hardwood hammock communities in southern Florida and halophytic communities such as buttonwood hammocks and mangroves. We further document from the literature how transpiration of mangroves and freshwater plants respond differently to vadose zone salinity, thus altering the salinity through feedback. Using mathematical models, we show how the self-reinforcing feedback, together with physical template, controls the ecotones between halophytic and freshwater communities. Regions of bistability along environmental gradients of salinity have the potential for large-scale vegetation shifts following pulse disturbances such as hurricane tidal surges in Florida, or tsunamis in other regions. The size of the region of bistability can be large for low-lying coastal habitat due to the saline water table, which extends inland due to salinity intrusion. We suggest coupling ecological and hydrologic processes as a framework for future studies.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Quinn, N.W.T.; Ortega, R.; Rahilly, P.
2011-12-17
The project has provided science-based tools for the long-term management of salinity in drainage discharges from wetlands to the San Joaquin River. The results of the project are being used to develop best management practices (BMP) and a decision support system to assist wetland managers adjust the timing of salt loads delivered to the San Joaquin River during spring drawdown. Adaptive drainage management scheduling has the potential to improve environmental compliance with salinity objectives in the Lower San Joaquin River by reducing the frequency of violation of Vernalis salinity standards, especially in dry and critically dry years. The paired approachmore » to project implementation whereby adaptively managed and traditional practices were monitored in a side-by-side fashion has provided a quantitative measure of the impacts of the project on the timing of salt loading to the San Joaquin River. The most significant accomplishments of the project has been the technology transfer to wetland biologists, ditch tenders and water managers within the Grasslands Ecological Area. This “learning by doing” has build local community capacity within the Grassland Water District and California Department of Fish and Game providing these institutions with new capability to assess and effectively manage salinity within their wetlands while simultaneously providing benefits to salinity management of the San Joaquin River.« less
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Effects of hydrologic connectivity on aquatic macroinvertebrate assemblages in different marsh types
Kang, Sung-Ryong; King, Sammy L.
2013-01-01
Hydrologic connectivity can be an important driver of aquatic macroinvertebrate assemblages. Its effects on aquatic macroinvertebrate assemblages in coastal marshes, however, are relatively poorly studied. We evaluated the effects of lateral hydrologic connectivity (permanently connected ponds: PCPs; temporary connected ponds: TCPs), and other environmental variables on aquatic macroinvertebrate assemblages and functional feeding groups (FFGs) in freshwater, brackish, and saline marshes in Louisiana, USA. We hypothesized that (1) aquatic macroinvertebrate assemblages in PCPs would have higher assemblage metric values (density, biomass, Shannon-Wiener diversity) than TCPs and (2) the density and proportional abundance of certain FFGs (i.e. scrapers, shredders, and collectors) would be greater in freshwater marsh than brackish and saline marshes. The data in our study only partially supported our first hypothesis: while freshwater marsh PCPs had higher density and biomass than TCPs, assemblage metric values in saline TCPs were greater than saline PCPs. In freshwater TCPs, long duration of isolation limited access of macroinvertebrates from adjacent water bodies, which may have reduced assemblage metric values. However, the relatively short duration of isolation in saline TCPs provided more stable or similar habitat conditions, facilitating higher assemblage metric values. As predicted by our second hypothesis, freshwater PCPs and TCPs supported a greater density of scrapers, shredders, and collectors than brackish and saline ponds. Aquatic macroinvertebrate assemblages seem to be structured by individual taxa responses to salinity as well as pond habitat attributes.
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Saranjampour, Parichehr; Vebrosky, Emily N; Armbrust, Kevin L
2017-09-01
Salinity has been reported to influence the water solubility of organic chemicals entering marine ecosystems. However, limited data are available on salinity impacts for chemicals potentially entering seawater. Impacts on water solubility would correspondingly impact chemical sorption as well as overall bioavailability and exposure estimates used in the regulatory assessment. The pesticides atrazine, fipronil, bifenthrin, and cypermethrin, as well as the crude oil constituent dibenzothiophene together with 3 of its alkyl derivatives, all have different polarities and were selected as model compounds to demonstrate the impact of salinity on their solubility and partitioning behavior. The n-octanol/water partition coefficient (K OW ) was measured in both distilled-deionized water and artificial seawater (3.2%). All compounds had diminished solubility and increased K OW values in artificial seawater compared with distilled-deionized water. A linear correlation curve estimated salinity may increase the log K OW value by 2.6%/1 log unit increase in distilled water (R 2 = 0.97). Salinity appears to generally decrease the water solubility and increase the partitioning potential. Environmental fate estimates based on these parameters indicate elevated chemical sorption to sediment, overall bioavailability, and toxicity in artificial seawater. These dramatic differences suggest that salinity should be taken into account when exposure estimates are made for marine organisms. Environ Toxicol Chem 2017;36:2274-2280. © 2017 SETAC. © 2017 SETAC.
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Metzger, David C H; Healy, Timothy M; Schulte, Patricia M
2016-10-01
In natural environments, organisms must cope with complex combinations of abiotic stressors. Here, we use threespine stickleback (Gasterosteus aculeatus) to examine how changes in salinity affect tolerance of high temperatures. Threespine stickleback inhabit a range of environments that vary in both salinity and thermal stability making this species an excellent system for investigating interacting stressors. We examined the effects of environmental salinity on maximum thermal tolerance (CTMax) and 70 kDa heat shock protein (hsp70) gene expression using divergent stickleback ecotypes from marine and freshwater habitats. In both ecotypes, the CTMax of fish acclimated to 20 ppt was significantly higher compared to fish acclimated to 2 ppt. The effect of salinity acclimation on the expression of hsp70-1 and hsp70-2 was similar in both the marine and freshwater stickleback ecotype. There were differences in the expression profiles of hsp70-1 and hsp70-2 during heat shock, with hsp70-2 being induced earlier and to a higher level compared to hsp70-1. These data suggest that the two hsp70 isoforms may have functionally different roles in the heat shock response. Lastly, acute salinity challenge coupled with heat shock revealed that the osmoregulatory demands experienced during the heat shock response have a larger effect on the hsp70 expression profile than does the acclimation salinity.
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Marine biogeographic realms and species endemicity.
Costello, Mark J; Tsai, Peter; Wong, Pui Shan; Cheung, Alan Kwok Lun; Basher, Zeenatul; Chaudhary, Chhaya
2017-10-20
Marine biogeographic realms have been inferred from small groups of species in particular environments (e.g., coastal, pelagic), without a global map of realms based on statistical analysis of species across all higher taxa. Here we analyze the distribution of 65,000 species of marine animals and plants, and distinguish 30 distinct marine realms, a similar proportion per area as found for land. On average, 42% of species are unique to the realms. We reveal 18 continental-shelf and 12 offshore deep-sea realms, reflecting the wider ranges of species in the pelagic and deep-sea compared to coastal areas. The most widespread species are pelagic microscopic plankton and megafauna. Analysis of pelagic species recognizes five realms within which other realms are nested. These maps integrate the biogeography of coastal and deep-sea, pelagic and benthic environments, and show how land-barriers, salinity, depth, and environmental heterogeneity relate to the evolution of biota. The realms have applications for marine reserves, biodiversity assessments, and as an evolution relevant context for climate change studies.
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Lagacé, François; Foucher, Delphine; Surette, Céline; Clarisse, Olivier
2017-05-15
Radium (Ra) at environmental relevant levels in natural waters was determined by ICP-MS after an off-line pre-concentration procedure. The latter consisted of Ra selective elution from potential interfering elements (i.e. other alkaline earth cations: Ba 2+ , Sr 2+ , Ca 2+ , Mg 2+ ) on a series of two different ion exchange resins (AG50W-X8 and Sr-resin). The overall analytical method was optimized according to the instrumental performance, the volume of water sample loaded on resins, and the sample salinity. Longer acquisition time (up to 150 s) was required to ensure stable measurement of Ra by ICP-MS at ultra trace level (1.0pgL -1 ). For a synthetic groundwater spiked with Ra at 10.0pgL -1 , the analytical procedure demonstrated efficient separation of the analyte from its potential interfering elements and a complete recovery, independent of the sample volume tested from 10 up to 100mL. For synthetic seawater spiked at a level of 10.0pgL -1 of Ra, the total load of salts on the two resins should not exceed 0.35g in order to ensure a complete separation and recovery of Ra. The method was validated on natural waters (i.e. groundwater, freshwater and seawater samples) spiked with Ra at different levels (0.0, 0.5, 1.0 and 5.0pgL -1 ). Absolute Ra detection limits were determined at 0.020pgL -1 (0.73mBqL -1 ) and 0.12pgL -1 (4.4mBqL -1 ) respectively for 60.0mL of freshwater sample and for 10.0mL of seawater. Copyright © 2017 Elsevier B.V. All rights reserved.
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Morash, Andrea J; Mackellar, Sara R C; Tunnah, Louise; Barnett, David A; Stehfest, Kilian M; Semmens, Jayson M; Currie, Suzanne
2016-01-01
Estuarine habitats are frequently used as nurseries by elasmobranch species for their protection and abundant resources; however, global climate change is increasing the frequency and severity of environmental challenges in these estuaries that may negatively affect elasmobranch physiology. Hyposmotic events are particularly challenging for marine sharks that osmoconform, and species-specific tolerances are not well known. Therefore, we sought to determine the effects of an acute (48 h) ecologically relevant hyposmotic event (25.8 ppt) on the physiology of two juvenile shark species, namely the school shark ( Galeorhinus galeus ), listed by the Australian Environmental Protection and Biodiversity Conservation Act as 'conservation dependent', and the gummy shark ( Mustelus antarcticus ), from the Pittwater Estuary (Australia). In both species, we observed a decrease in plasma osmolality brought about by selective losses of NaCl, urea and trimethylamine N -oxide, as well as decreases in haemoglobin, haematocrit and routine oxygen consumption. Heat-shock protein levels varied between species during the exposure, but we found no evidence of protein damage in any of the tissues tested. Although both species seemed to be able to cope with this level of osmotic challenge, overall the school sharks exhibited higher gill Na + /K + -ATPase activity and ubiquitin concentrations in routine and experimental conditions, a larger heat-shock protein response and a smaller decrease in routine oxygen consumption during the hyposmotic exposure, suggesting that there are species-specific responses that could potentially affect their ability to withstand longer or more severe changes in salinity. Emerging evidence from acoustic monitoring of sharks has indicated variability in the species found in the Pittwater Estuary during hyposmotic events, and together, our data may help to predict species abundance and distribution in the face of future global climate change.
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Morash, Andrea J.; Mackellar, Sara R. C.; Tunnah, Louise; Barnett, David A.; Stehfest, Kilian M.; Semmens, Jayson M.; Currie, Suzanne
2016-01-01
Estuarine habitats are frequently used as nurseries by elasmobranch species for their protection and abundant resources; however, global climate change is increasing the frequency and severity of environmental challenges in these estuaries that may negatively affect elasmobranch physiology. Hyposmotic events are particularly challenging for marine sharks that osmoconform, and species-specific tolerances are not well known. Therefore, we sought to determine the effects of an acute (48 h) ecologically relevant hyposmotic event (25.8 ppt) on the physiology of two juvenile shark species, namely the school shark (Galeorhinus galeus), listed by the Australian Environmental Protection and Biodiversity Conservation Act as ‘conservation dependent’, and the gummy shark (Mustelus antarcticus), from the Pittwater Estuary (Australia). In both species, we observed a decrease in plasma osmolality brought about by selective losses of NaCl, urea and trimethylamine N-oxide, as well as decreases in haemoglobin, haematocrit and routine oxygen consumption. Heat-shock protein levels varied between species during the exposure, but we found no evidence of protein damage in any of the tissues tested. Although both species seemed to be able to cope with this level of osmotic challenge, overall the school sharks exhibited higher gill Na+/K+-ATPase activity and ubiquitin concentrations in routine and experimental conditions, a larger heat-shock protein response and a smaller decrease in routine oxygen consumption during the hyposmotic exposure, suggesting that there are species-specific responses that could potentially affect their ability to withstand longer or more severe changes in salinity. Emerging evidence from acoustic monitoring of sharks has indicated variability in the species found in the Pittwater Estuary during hyposmotic events, and together, our data may help to predict species abundance and distribution in the face of future global climate change. PMID:27757235
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Sublethal toxicity of chlorpyrifos to salmonid olfaction after hypersaline acclimation.
Maryoung, Lindley A; Blunt, Brian; Tierney, Keith B; Schlenk, Daniel
2015-04-01
Salmonid habitats can be impacted by several environmental factors, such as salinization, which can also affect salmonid tolerance to anthropogenic stressors, such as pesticides. Previous studies have shown that hypersaline acclimation enhances the acute toxicity of certain organophosphate and carbamate pesticides to euryhaline fish; however, sublethal impacts have been far less studied. The current study aims to determine how hypersaline acclimation and exposure to the organophosphate chlorpyrifos (CPF) impact salmonid olfaction. Combined acclimation and exposure to CPF was shown to impact rainbow trout olfaction at the molecular, physiological, and behavioral levels. Concurrent exposure to hypersalinity and 0.5μg/L CPF upregulated four genes (chloride intracellular channel 4, G protein zgc:101761, calcium calmodulin dependent protein kinase II delta, and adrenergic alpha 2C receptor) that inhibit olfactory signal transduction. At the physiological level, hypersalinity and chlorpyrifos caused a decrease in sensory response to the amino acid l-serine and the bile salt taurocholic acid. Combined acclimation and exposure also negatively impacted behavior and reduced the avoidance of a predator cue (l-serine). Thus, acclimation to hypersaline conditions and exposure to environmentally relevant concentrations of chlorpyrifos caused an inhibition of olfactory signal transduction leading to a decreased response to odorants and impairment of olfactory mediated behaviors. Copyright © 2015 Elsevier B.V. All rights reserved.
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Spatiotemporal Variation in Environmental Vibrio cholerae in an Estuary in Southern Coastal Ecuador.
Ryan, Sadie J; Stewart-Ibarra, Anna M; Ordóñez-Enireb, Eunice; Chu, Winnie; Finkelstein, Julia L; King, Christine A; Escobar, Luis E; Lupone, Christina; Heras, Froilan; Tauzer, Erica; Waggoner, Egan; James, Tyler G; Cárdenas, Washington B; Polhemus, Mark
2018-03-10
Cholera emergence is strongly linked to local environmental and ecological context. The 1991-2004 pandemic emerged in Perú and spread north into Ecuador's El Oro province, making this a key site for potential re-emergence. Machala, El Oro, is a port city of 250,000 inhabitants, near the Peruvian border. Many livelihoods depend on the estuarine system, from fishing for subsistence and trade, to domestic water use. In 2014, we conducted biweekly sampling for 10 months in five estuarine locations, across a gradient of human use, and ranging from inland to ocean. We measured water-specific environmental variables implicated in cholera growth and persistence: pH, temperature, salinity, and algal concentration, and evaluated samples in five months for pathogenic and non-pathogenic Vibrio cholerae , by polymerase chain reaction (PCR). We found environmental persistence of pandemic strains O1 and O139, but no evidence for toxigenic strains. Vibrio cholerae presence was coupled to algal and salinity concentration, and sites exhibited considerable seasonal and spatial heterogeneity. This study indicates that environmental conditions in Machala are optimal for cholera re-emergence, with risk peaking during September, and higher risk near urban periphery low-income communities. This highlights a need for surveillance of this coupled cholera-estuarine system to anticipate potential future cholera outbreaks.
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Spatiotemporal Variation in Environmental Vibrio cholerae in an Estuary in Southern Coastal Ecuador
Stewart-Ibarra, Anna M.; Ordóñez-Enireb, Eunice; Chu, Winnie; Finkelstein, Julia L.; King, Christine A.; Escobar, Luis E.; Lupone, Christina; Heras, Froilan; Tauzer, Erica; Waggoner, Egan; Polhemus, Mark
2018-01-01
Cholera emergence is strongly linked to local environmental and ecological context. The 1991–2004 pandemic emerged in Perú and spread north into Ecuador’s El Oro province, making this a key site for potential re-emergence. Machala, El Oro, is a port city of 250,000 inhabitants, near the Peruvian border. Many livelihoods depend on the estuarine system, from fishing for subsistence and trade, to domestic water use. In 2014, we conducted biweekly sampling for 10 months in five estuarine locations, across a gradient of human use, and ranging from inland to ocean. We measured water-specific environmental variables implicated in cholera growth and persistence: pH, temperature, salinity, and algal concentration, and evaluated samples in five months for pathogenic and non-pathogenic Vibrio cholerae, by polymerase chain reaction (PCR). We found environmental persistence of pandemic strains O1 and O139, but no evidence for toxigenic strains. Vibrio cholerae presence was coupled to algal and salinity concentration, and sites exhibited considerable seasonal and spatial heterogeneity. This study indicates that environmental conditions in Machala are optimal for cholera re-emergence, with risk peaking during September, and higher risk near urban periphery low-income communities. This highlights a need for surveillance of this coupled cholera–estuarine system to anticipate potential future cholera outbreaks. PMID:29534431
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Guillaumot, Charlène; Martin, Alexis; Fabri-Ruiz, Salomé; Eléaume, Marc; Saucède, Thomas
2016-01-01
The present dataset provides a case study for species distribution modelling (SDM) and for model testing in a poorly documented marine region. The dataset includes spatially-explicit data for echinoid (Echinodermata: Echinoidea) distribution. Echinoids were collected during oceanographic campaigns led around the Kerguelen Plateau (+63°/+81°E; -46°/-56°S) since 1872. In addition to the identification of collection specimens from historical cruises, original data from the recent campaigns POKER II (2010) and PROTEKER 2 to 4 (2013-2015) are also provided. In total, five families, ten genera, and 12 echinoid species are recorded in the region of the Kerguelen Plateau. The dataset is complemented with environmental descriptors available and relevant for echinoid ecology and SDM. The environmental data was compiled from different sources and was modified to suit the geographic extent of the Kerguelen Plateau, using scripts developed with the R language (R Core Team 2015). Spatial resolution was set at a common 0.1° pixel resolution. Mean seafloor and sea surface temperatures, salinity and their amplitudes, all derived from the World Ocean Database (Boyer et al. 2013) are made available for the six following decades: 1955-1964, 1965-1974, 1975-1984, 1985-1994, 1995-2004, 2005-2012. Future projections are provided for several parameters: they were modified from the Bio-ORACLE database (Tyberghein et al. 2012). They are based on three IPCC scenarii (B1, AIB, A2) for years 2100 and 2200 (IPCC, 4 th report).
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Central Connections of the Lacrimal Functional Unit.
Willshire, Catherine; Buckley, Roger J; Bron, Anthony J
2017-08-01
To study the contribution of each eye to the reflex tear response, after unilateral and bilateral topical anesthesia. A closed-eye, modified Schirmer test was performed bilaterally in 8 normal subjects, in a controlled environment chamber set to 23°C, 45% relative humidity, and 0.08 m/s airflow. Eye drops were instilled into each eye 10 minutes before the Schirmer test. Experiments were as follows: 1) bilateral saline (control), 2) unilateral anesthesia (ipsilateral anesthetic; contralateral saline), and 3) bilateral anesthesia. There was no difference in between-eye wetting lengths in the saline control eyes (P = 0.394) or the bilaterally anesthetized eyes (P = 0.171). The wetting length was reduced in both eyes after bilateral anesthesia compared with saline controls (P = 0.001; P ≤ 0.0005). After unilateral anesthesia, the wetting length was reduced in the anesthetized eye compared with its saline control by 51.4% (P ≤ 0.0005) and compared with its fellow, unanesthetized eye (P = 0.005). The fellow eye value was also reduced compared with its saline control (P = 0.06). The wetting length was reduced by topical anesthesia, when instilled bilaterally and ipsilaterally. The latter response implies an ipsilateral, reflex sensory drive to lacrimal secretion. In the unanesthetized fellow eye, the reduction compared with its saline control was not quite significant. This implies a relative lack of central, sensory, reflex cross-innervation, although the possibility cannot entirely be ruled out. These results are relevant to the possibility of reflex lacrimal compensation from a normal fellow eye, in cases of unilateral corneal anesthesia.
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The Measurement of Dissolved Oxygen
ERIC Educational Resources Information Center
Thistlethwayte, D.; And Others
1974-01-01
Describes an experiment in environmental chemistry which serves to determine the dissolved oxygen concentration in both fresh and saline water. Applications of the method at the undergraduate and secondary school levels are recommended. (CC)
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Aggressive desert goby males also court more, independent of the physiological demands of salinity.
Lehtonen, Topi K; Svensson, P Andreas; Wong, Bob B M
2018-06-19
Both between- and within-individual variation in behaviour can be important in determining mating opportunities and reproductive outcomes. Such behavioural variability can be induced by environmental conditions, especially if individuals vary in their tolerance levels or resource allocation patterns. We tested the effects of exposure to different salinity levels on male investment into two important components of mating success-intrasexual aggression and intersexual courtship-in a fish with a resource defence mating system, the desert goby, Chlamydogobius eremius. We found that males that were more aggressive to rivals also exhibited higher rates of courtship displays towards females. Contrary to predictions, this positive relationship, and the consistency of the two behaviours, were not affected by the salinity treatment, despite the physiological costs that high salinity imposes on the species. Moreover, over the entire data-set, there was only a marginally non-significant tendency for males to show higher levels of aggression and courtship in low, than high, salinity. The positive correlation between male aggression and courtship, independent of the physiological demands of the environment, suggests that males are not inclined to make contrasting resource investments into these two key reproductive behaviours. Instead, in this relatively euryhaline freshwater species, typical investment into current reproductive behaviours can occur under a range of different salinity conditions.
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Effects of saline drinking water on early gosling development
Stolley, D.S.; Bissonette, J.A.; Kadlec, J.A.; Coster, D.
1999-01-01
Relatively high levels of saline drinking water may adversely affect the growth, development, and survival of young waterfowl. Saline drinking water was suspect in the low survival rate of Canada goose (Branta canadensis) goslings at Fish Springs National Wildlife Refuge (FSNWR) in western Utah. Hence, we investigated the effects of saline drinking water on the survival and growth of captive, wild-strain goslings from day 1-28 following hatch. We compared survival and growth (as measured by body mass, wing length, and culmen length) between a control group on tap water with a mean specific conductivity of 650 ??S/cm, and 2 saline water treatments: (1) intermediate level (12,000 ??S/cm), and (2) high level (18,000 ??S/cm). Gosling mortality occurred only in the 18,000 ??S/cm treatment group (33%; n = 9). Slopes of regressions of mean body mass, wing length, and culmen length on age were different from each other (P < 0.05), except for culmen length for the intermediate and high treatment levels. We predict that free-ranging wild goslings will experience mortality at even lower salinity levels than captive goslings because of the combined effects of depressed growth and environmental stresses, including hot desert temperatures and variable food quality over summer.
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Martins, Y S; Melo, R M C; Campos-Junior, P H A; Santos, J C E; Luz, R K; Rizzo, E; Bazzoli, N
2014-06-01
The present study assessed the influence of salinity and temperature on body growth and on muscle cellularity of Lophiosilurus alexaxdri vitelinic larvae. Slightly salted environments negatively influenced body growth of freshwater fish larvae and we observed that those conditions notably act as an environmental influencer on muscle growth and on local expression of hypertrophia and hypeplasia markers (IGFs and PCNA). Furthermore, we could see that salinity tolerance for NaCl 4gl(-)(1) diminishes with increasing temperature, evidenced by variation in body and muscle growth, and by irregular morphology of the lateral skeletal muscle of larvae. We saw that an increase of both PCNA and autocrine IGF-II are correlated to an increase in fibre numbers and fibre diameter as the temperature increases and salinity diminishes. On the other hand, autocrine IGF-I follows the opposite way to the other biological parameters assessed, increasing as salinity increases and temperature diminishes, showing that this protein did not participate in muscle cellularity, but participating in molecular/cellular repair. Therefore, slightly salted environments may provide adverse conditions that cause some obstacles to somatic growth of this species, suggesting some osmotic expenditure with a salinity increment. Copyright © 2014 Elsevier Inc. All rights reserved.
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The plasma membrane transport systems and adaptation to salinity.
Mansour, Mohamed Magdy F
2014-11-15
Salt stress represents one of the environmental challenges that drastically affect plant growth and yield. Evidence suggests that glycophytes and halophytes have a salt tolerance mechanisms working at the cellular level, and the plasma membrane (PM) is believed to be one facet of the cellular mechanisms. The responses of the PM transport proteins to salinity in contrasting species/cultivars were discussed. The review provides a comprehensive overview of the recent advances describing the crucial roles that the PM transport systems have in plant adaptation to salt. Several lines of evidence were presented to demonstrate the correlation between the PM transport proteins and adaptation of plants to high salinity. How alterations in these transport systems of the PM allow plants to cope with the salt stress was also addressed. Although inconsistencies exist in some of the information related to the responses of the PM transport proteins to salinity in different species/cultivars, their key roles in adaptation of plants to high salinity is obvious and evident, and cannot be precluded. Despite the promising results, detailed investigations at the cellular/molecular level are needed in some issues of the PM transport systems in response to salinity to further evaluate their implication in salt tolerance. Copyright © 2014 Elsevier GmbH. All rights reserved.
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Poverty, population and environmental degradation in China.
Rozelle, S; Huang, J; Zhang, L
1997-06-01
This article examines the relationship between poverty, population, and environmental degradation in China. Environmental conditions include water pollution, deforestation, destruction of grasslands, soil erosion, and salinization. The authors review China's success in controlling environmental degradation through leadership, environmental policies, and institutional capacity. Findings suggest that environmental progress is best achieved indirectly by poverty alleviation, market integration, and population control. Government policies were not very effective. Degradation occurs due to limited financial resources, poorly trained personnel, and political factors. Control of water pollution was instituted since the 1980s. The levels of pollutants have been reduced, but the type of pollutant determines the seriousness of impact. Water pollution is due to industrial wastes, agricultural run-off, and soil erosion. Since the 1970s, reforestation targets have not been met. Technical extension and monitoring of planting is not available in most areas, and private, profit seeking interests control acreage. Grassland destruction is due to deforestation, agricultural expansion, and overgrazing. Independent regional authorities have successfully managed pasture programs. Erosion is the most serious in Loess Plateau, the Red Soils area, the Northeast China Plain, and the Northwest Grasslands, which comprise 70% of total land area. In 1990, erosion control was practiced in 39% of eroded land area. Salinization has remained fairly constant. Environmental controls (direct regulation, planned recovery, and state-mandated technological improvements) are uneven. The main tool for environmental management is the State Environmental Protection Commission and its executive unit, SEPA. Problems stem from vague laws, lack of means of enforcement, lack of coordination of laws, and lack of standards, schedules, and other provisions in ordinances.
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Fish community structure and dynamics in a coastal hypersaline lagoon: Rio Lagartos, Yucatan, Mexico
NASA Astrophysics Data System (ADS)
Vega-Cendejas, Ma. Eugenia; Hernández de Santillana, Mireya
2004-06-01
Rio Lagartos, a tropical coastal lagoon in northern Yucatan Peninsula of Mexico, is characterized by high salinity during most of the year (55 psu annual average). Even though the area has been designated as a wetland of international importance because of its great biodiversity, fish species composition and distribution are unknown. To determine whether the salinity gradient was influencing fish assemblages or not, fish populations were sampled seasonally by seine and trawl from 1992 to 1993 and bimonthly during 1997. We identified 81 fish species, eight of which accounted for 53.1% considering the Importance Value Index ( Floridichthys polyommus, Sphoeroides testudineus, Eucinostomus argenteus, Eucinostomus gula, Fundulus majalis, Strongylura notata, Cyprinodon artifrons and Elops saurus). Species richness and density declined from the mouth to the inner zone where extreme salinity conditions are prominent (>80) and competitive interactions decreased. However, in Coloradas basin (53 average sanity) and in the inlet of the lagoon, the highest fish density and number of species were observed. Greater habitat heterogeneity and fish immigration were considered as the best explanation. Multivariate analysis found three zones distinguished by fish occurrence, abundance and distribution. Ichthyofaunal spatial differences were attributed to selective recruitment from the Gulf of Mexico due to salinity gradient and to changing climatic periods. Estuarine and euryhaline marine species are abundant, with estuarine dependent ones entering the system according to environmental preferences. This knowledge will contribute to the management of the Special Biosphere Reserve through baseline data to evaluate environmental and anthropogenic changes.
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Xu, Yuan; Vick-Majors, Trista; Morgan-Kiss, Rachael; Priscu, John C; Amaral-Zettler, Linda
2014-10-01
We report an in-depth survey of next-generation DNA sequencing of ciliate diversity and community structure in two permanently ice-covered McMurdo Dry Valley lakes during the austral summer and autumn (November 2007 and March 2008). We tested hypotheses on the relationship between species richness and environmental conditions including environmental extremes, nutrient status, and day length. On the basis of the unique environment that exists in these high-latitude lakes, we expected that novel taxa would be present. Alpha diversity analyses showed that extreme conditions-that is, high salinity, low oxygen, and extreme changes in day length-did not impact ciliate richness; however, ciliate richness was 30% higher in samples with higher dissolved organic matter. Beta diversity analyses revealed that ciliate communities clustered by dissolved oxygen, depth, and salinity, but not by season (i.e., day length). The permutational analysis of variance test indicated that depth, dissolved oxygen, and salinity had significant influences on the ciliate community for the abundance matrices of resampled data, while lake and season were not significant. This result suggests that the vertical trends in dissolved oxygen concentration and salinity may play a critical role in structuring ciliate communities. A PCR-based strategy capitalizing on divergent eukaryotic V9 hypervariable region ribosomal RNA gene targets unveiled two new genera in these lakes. A novel taxon belonging to an unknown class most closely related to Cryptocaryon irritans was also inferred from separate gene phylogenies. © 2014 Marine Biological Laboratory.
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Carter, J.; Merino, J.H.; Merino, S.L.
2009-01-01
Estimates of submerged aquatic vegetative (SAV) along the U.S. Gulf of Mexico (Gulf) generally focus on seagrasses. In 2000, we attempted a synoptic survey of SAV in the mesohaline (5-20 ppt) zone of estuarine and nearshore areas of the northeastern Gulf. Areas with SAV were identified from existing aerial 1992 photography, and a literature review was used to select those areas that were likely to experience mesohaline conditions during the growing season. In 2000, a drought year, we visited 217 randomly selected SAV beds and collected data on species composition and environmental conditions. In general, sites were either clearly polyhaline (2: 20 ppt) or oligohaline (S 5 ppt), with only five sites measuring between 5 and 20 ppt. Ruppia maritima L. (13-35 ppt, n = 28) was the only species that occurred in mesohaline salinities. Halodule wrightii Asch. occurred in 73% of the beds. The nonindigenous Myriophyllum spicatum L. was present in four locations with salinities below 3 ppt. No nonindigenous macroalgae were identified, and no nonindigenous angiosperms occurred in salinities above 3 ppt. Selecting sample locations based on historical salinity data was not a successful strategy for surveying SAV in mesohaline systems, particularly during a drought year. Our ability to locate SAV beds within 50 m of their aerially located position 8 yr later demonstrates some SAV stability in the highly variable conditions of the study area. ?? 2009 by the Marine Environmental Silences Consortium of Alabama.
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Biofuel as an Integrated Farm Drainage Management crop: A bioeconomic analysis
NASA Astrophysics Data System (ADS)
Levers, L. R.; Schwabe, K. A.
2017-04-01
Irrigated agricultural lands in arid regions often suffer from soil salinization and lack of drainage, which affect environmental quality and productivity. Integrated Farm Drainage Management (IFDM) systems, where drainage water generated from higher-valued crops grown on high quality soils are used to irrigate salt-tolerant crops grown on marginal soils, is one possible strategy for managing salinity and drainage problems. If the IFDM crop were a biofuel crop, both environmental and private benefits may be generated; however, little is known about this possibility. As such, we develop a bioeconomic programming model of irrigated agricultural production to examine the role salt-tolerant biofuel crops might play within an IFDM system. Our results, generated by optimizing profits over land, water, and crop choice decisions subject to resource constraints, suggest that based on the private profits alone, biofuel crops can be a competitive alternative to the common practices of land retirement and nonbiofuel crop production under both low to high drainage water salinity. Yet IFDM biofuel crop production generates 30-35% fewer GHG emissions than the other strategies. The private market competitiveness coupled with the public good benefits may justify policy changes encouraging the growth of IFDM biofuel crops in arid agricultural areas globally.
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Freese, Luana; Almeida, Felipe Borges; Heidrich, Nubia; Hansen, Alana Witt; Steffens, Luiza; Steinmetz, Aline; Moura, Dinara Jaqueline; Gomez, Rosane; Barros, Helena Maria Tannhauser
2018-06-01
Environmental enrichment (EE) has a neuroprotective role and prevents the development of cocaine addiction behavior in rats. Studies showing the role of EE in cocaine toxicity are nonexistent. We hypothesized that rats exposed to EE are protected from cocaine-induced changes in the redox profile and DNA damage after undergoing conditioned place preference (CPP). Ten male Wistar rats were placed in EE cages equipped with toys, a ladder and tunnels, and ten were provided clean, standard laboratory housing (non-EE). EE and non-EE rats were randomly allocated to the classical CPP cocaine vs. saline (COC/Saline) group, where cocaine (15 mg/kg; i.p.) was tested alternately with saline. Afterwards, intracellular reactive species and antioxidant enzymes were evaluated and the comet essay was performed in the prefrontal cortex and hippocampus of rats. As expected, EE rats spent less time in the cocaine-paired chamber, and as a new result, less cocaine-induced DNA damage was observed in the two brain structures. Altogether, our results demonstrate that EE decreases neurotoxicity in brain regions linked to cocaine addiction but does not extinguish it completely. Copyright © 2018. Published by Elsevier Inc.
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Geilfus, Christoph-Martin; Tenhaken, Raimund; Carpentier, Sebastien Christian
2017-11-17
During chloride salinity, the pH of the leaf apoplast (pH apo ) transiently alkalizes. There is an ongoing debate about the physiological relevance of these stress-induced pH apo changes. Using proteomic analyses of expanding leaves of corn ( Zea mays L.), we show that this transition in pH apo conveys functionality by (i) adjusting protein abundances and (ii) affecting the rheological properties of the cell wall. pH apo was monitored in planta via microscopy-based ratio imaging, and the leaf-proteomic response to the transient leaf apoplastic alkalinization was analyzed via ultra-high performance liquid chromatography-MS. This analysis identified 1459 proteins, of which 44 exhibited increased abundance specifically through the chloride-induced transient rise in pH apo These elevated protein abundances did not directly arise from high tissue concentrations of Cl - or Na + but were due to changes in the pH apo Most of these proteins functioned in growth-relevant processes and in the synthesis of cell wall-building components such as arabinose. Measurements with a linear-variable differential transducer revealed that the transient alkalinization rigidified ( i.e. stiffened) the cell wall during the onset of chloride salinity. A decrease in t -coumaric and t -ferulic acids indicates that the wall stiffening arises from cross-linkage to cell wall polymers. We conclude that the pH of the apoplast represents a dynamic factor that is mechanistically coupled to cellular responses to chloride stress. By hardening the wall, the increased pH abrogates wall loosening required for cell expansion and growth. We conclude that the transient alkalinization of the leaf apoplast is related to salinity-induced growth reduction. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Fay, C.W.; Neves, R.J.; Pardue, G.B.
1983-10-01
Species profiles are literature summaries on the taxonomy, morphology, range, life history, and environmental requirements of coastal aquatic species. The striped bass (Morone saxatilis) is a highly valued recreational and commercial fish species and is surpassed in total recreational catch (weight) only by bluefish and Atlantic mackerel on the Atlantic coast. Males mature at age 2 or 3, and females at age 4 or 5. Striped bass are anadromous, spawning in fresh or nearly fresh water, from April through June in the Mid-Atlantic region. Upper Chesapeake Bay, its major tributaries, and the Chesapeake-Delaware Canal are the most important spawning groundsmore » on the Atlantic coast. Eggs are semibuoyant, and require a minimum current velocity of 30.5 cm/s during development to keep them from settling and smothering on the bottom. Environmental conditions during the larval stage are considered most crucial in terms of future year class strength. Juveniles remain in or near areas of origin for 2 or 3 years, at which time a portion of the juveniles may join coastal migratory stocks, moving north in spring and summer and south in fall and winter. Temperature, salinity, current velocity, and turbidity are important environmental factors for striped bass. Eggs require water temperatures between 14/sup 0/C and 23/sup 0/C, salinities between 0 and 10 ppt, water currents of at least 30.5 cm/s, and turbidities less than 1000 mg/l for successful development and hatching. Larvae require temperatures between 10/sup 0/C and 25/sup 0/C, salinities between 0 and 15 ppt, and turbidities less than 500 mg/1 for survival. Juvenile and adult tolerances are generally wider. 171 references, 4 figures, 9 tables.« less
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Serratore, Patrizia; Ostanello, Fabio; Passalacqua, Pier Luca; Zavatta, Emanuele; Bignami, Giorgia; Serraino, Andrea; Giacometti, Federica
2016-09-20
The present work describes a retrospective study aiming to verify a possible correlation between the environmental conditions (temperature, salinity and dissolved oxygen), the abundance of Vibrio spp., and the prevalence of V. parahaemolyticus and V. vulnificus in the Manila clam R. philippinarum harvested in Sacca di Goro, Emilia-Romagna Region, Northern Italy. On the whole, 104 samples, collected in the period 2007-2015 and submitted to microbiological analyses (isolation and genotyping), have been reconsidered for Vibrio spp. load, V. parahaemolyticus prevalence (total, gene marker toxRP; potentially pathogenic, gene markers tdh and/or trh) and V. vulnificus prevalence (total, gene markers vvh A and hsp) together with environmental data obtained from the monitoring activity of the Emilia-Romagna Regional Agency for the Prevention, the Environment and the Energy. Environmental data have been processed to calculate the median of each, assessing the seasonal range of seawater temperature (warmer months: April-October, T°C >16.45°C; cooler months November-March, T°C <16.45°C), salinity (
27 psu), and dissolved oxygen (< or >8.2 mg/L). Total V. vulnificus , total and potentially pathogenic V. parahaemolyticus were present respectively in the 11.5, 29.8 and 6.7% of the samples. The Vibrio spp. load (mean value of 4.69±0.65 log 10 colony forming unit g -1 ) and the prevalence of potentially pathogenic V. parahaemolyticus , were not significantly correlated to the environmental conditions (P>0.05), whereas the prevalence of both total V. vulnificus and total V. parahaemolyticus was significantly higher in the warmer period (P<0.05), without correlation with salinity and dissolved oxygen values (P>0.05). -
Cao, Da; Lutz, Adrian; Hill, Camilla B.; Callahan, Damien L.; Roessner, Ute
2017-01-01
As integral parts of plant signaling networks, phytohormones are involved in the regulation of plant metabolism and growth under adverse environmental conditions, including salinity. Globally, salinity is one of the most severe abiotic stressors with an estimated 800 million hectares of arable land affected. Roots are the first plant organ to sense salinity in the soil, and are the initial site of sodium (Na+) exposure. However, the quantification of phytohormones in roots is challenging, as they are often present at extremely low levels compared to other plant tissues. To overcome this challenge, we developed a high-throughput LC-MS method to quantify ten endogenous phytohormones and their metabolites of diverse chemical classes in roots of barley. This method was validated in a salinity stress experiment with six barley varieties grown hydroponically with and without salinity. In addition to phytohormones, we quantified 52 polar primary metabolites, including some phytohormone precursors, using established GC-MS and LC-MS methods. Phytohormone and metabolite data were correlated with physiological measurements including biomass, plant size and chlorophyll content. Root and leaf elemental analysis was performed to determine Na+ exclusion and K+ retention ability in the studied barley varieties. We identified distinct phytohormone and metabolite signatures as a response to salinity stress in different barley varieties. Abscisic acid increased in the roots of all varieties under salinity stress, and elevated root salicylic acid levels were associated with an increase in leaf chlorophyll content. Furthermore, the landrace Sahara maintained better growth, had lower Na+ levels and maintained high levels of the salinity stress linked metabolite putrescine as well as the phytohormone metabolite cinnamic acid, which has been shown to increase putrescine concentrations in previous studies. This study highlights the importance of root phytohormones under salinity stress and the multi-variety analysis provides an important update to analytical methodology, and adds to the current knowledge of salinity stress responses in plants at the molecular level. PMID:28119732
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Huang, Xizhi; Lan, Yawen; Liu, Zekang; Huang, Wei; Guo, Qindan; Liu, Liping; Hu, Menghong; Sui, Yanming; Wu, Fangli; Lu, Weiqun; Wang, Youji
2018-06-04
Increased production of engineered nanoparticles has raised extensive concern about the potential toxic effects on marine organisms living in estuarine and coastal environments. Meanwhile, salinity is one of the key environmental factors that may influence the physiological activities in flatfish species inhabiting in those waters due to fluctuations caused by freshwater input or rainfall. In this study, we investigated the oxidative stress and histopathological alteration of the juvenile Paralichthys olivaceus exposed to nano-TiO 2 (1 and 10 mg L -1 ) under salinities of 10 and 30 psu for 4 days. In the gills, Na + -K + -ATPase activity significantly deceased after 4 days 10 psu exposure without nano-TiO 2 compared with 1 day of acclimating the salinity from the normal salinity (30 psu) to 10 psu. Under this coastal salinity, low concentration (1 mg L -1 ) of nano-TiO 2 exerted significant impacts. In the liver, the activities of superoxide dismutase, catalase, the levels of lipid peroxide and malondialdehyde increased with nano-TiO 2 exposed under 30 psu. Such increase indicated an oxidative stress response. The result of the integrated biomarker responses showed that P. olivaceus can be adversely affected by high salinity and high concentration of nano-TiO 2 for a short-term (4 days) exposure. The histological analysis revealed the accompanying severe damages for the gill filaments. Principal component analysis further showed that the oxidative stress was associated with the nano-TiO 2 effect at normal salinity. These findings indicated that nano-TiO 2 and normal salinity exert synergistic effects on juvenile P. olivaceus, and low salinity plays a protective role in its physiological state upon short-term exposure to nano-TiO 2 . The mechanism of salinity mediating the toxic effects of NPs on estuarine fish should be further considered. Copyright © 2018 Elsevier B.V. All rights reserved.
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Huang, Y; Song, Y; Li, G; Drake, P L; Zheng, W; Li, Z; Zhou, D
2015-11-01
The abundance and distribution of species can be ascribed to both environmental heterogeneity and stress tolerance, with the latter measure sometimes associated with phenotypic plasticity. Although phenotypic plasticity varies predictably in response to common forms of stress, we lack a mechanistic understanding of the response of species to high saline-sodic soils. We compared the phenotypic plasticity of three pairs of high and low saline-sodic tolerant congeners from the families Poaceae (Leymus chinensis versus L. secalinus), Fabaceae (Lespedeza davurica versus L. bicolor) and Asteraceae (Artemisia mongolica versus A. sieversiana) in a controlled pot experiment in the Songnen grassland, China. The low tolerant species, L. secalinus and A. sieversiana exhibited higher plasticity in response to soil salinity and sodicity than their paired congeners. Highly tolerant species, L. chinensis and A. mongolica, had higher values for several important morphological traits, such as shoot length and total biomass under the high saline-sodic soil treatment than their paired congeners. In contrast, congeners from the family Fabaceae, L. davurica and L. bicolor, did not exhibit significantly different plasticity in response to soil salinity and sodicity. All species held a constant reproductive effort in response to saline-sodic soil stress. The different responses between low and high tolerant species offer an explanation for the distribution patterns of these species in the Songnen grassland. Highly tolerant species showed less morphological plasticity over a range of saline-sodic conditions than their paired congeners, which may manifest as an inability to compete with co-occurring species in locations where saline-sodic soils are absent. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.
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NASA Astrophysics Data System (ADS)
Zheng, Yanling; Jiang, Xiaofen; Hou, Lijun; Liu, Min; Lin, Xianbiao; Gao, Juan; Li, Xiaofei; Yin, Guoyu; Yu, Chendi; Wang, Rong
2016-06-01
Anaerobic ammonium oxidation (anammox) is a major microbial pathway for nitrogen (N) removal in estuarine and coastal environments. However, understanding of anammox bacterial dynamics and associations with anammox activity remains scarce along estuarine salinity gradient. In this study, the diversity, abundance, and activity of anammox bacteria, and their potential contributions to total N2 production in the sediments along the salinity gradient (0.1-33.8) of the Yangtze estuarine and coastal zone, were studied using 16S rRNA gene clone library, quantitative polymerase chain reaction assay, and isotope-tracing technique. Phylogenetic analysis showed a significant change in anammox bacterial community structure along the salinity gradient (P < 0.01), with the dominant genus shifting from Brocadia in the freshwater region to Scalindua in the open ocean. Anammox bacterial abundance ranged from 3.67 × 105 to 8.22 × 107 copies 16S rRNA gene g-1 and related significantly with salinity (P < 0.05). The anammox activity varied between 0.08 and 6.46 nmol N g-1 h-1 and related closely with anammox bacterial abundance (P < 0.01). Contributions of anammox activity to total N loss were highly variable along the salinity gradient, ranging from 5 to 77% and were significantly negatively correlated with salinity (P < 0.01). Sediment organic matter was also recognized as an important factor in controlling the relative role of anammox to total N2 production in the Yangtze estuarine and coastal zone. Overall, our data demonstrated a biogeographical distribution of anammox bacterial diversity, abundance, and activity along the estuarine salinity gradient and suggested that salinity is a major environmental control on anammox process in the estuarine and coastal ecosystems.
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The osmoregulatory effects of rearing Mozambique tilapia in a tidally changing salinity.
Moorman, Benjamin P; Inokuchi, Mayu; Yamaguchi, Yoko; Lerner, Darren T; Grau, E Gordon; Seale, Andre P
2014-10-01
The native distribution of Mozambique tilapia, Oreochromis mossambicus, is characterized by estuarine areas subject to salinity variations between fresh water (FW) and seawater (SW) with tidal frequency. Osmoregulation in the face of changing environmental salinity is largely mediated through the neuroendocrine system and involves the activation of ion uptake and extrusion mechanisms in osmoregulatory tissues. We compared plasma osmolality, plasma prolactin (PRL), pituitary PRL mRNA, and mRNA of branchial ion pumps, transporters, channels, and PRL receptors in tilapia reared in FW, SW, brackish water (BW) and in tidally-changing salinity, which varied between FW (TF) and SW (TS) every 6h. Plasma PRL was higher in FW tilapia than in SW, BW, TF, and TS tilapia. Unlike tilapia reared in FW or SW, fish in salinities that varied tidally showed no correlation between plasma osmolality and PRL. In FW fish, gene expression of PRL receptor 1 (PRLR1), Na(+)/Cl(-) cotransporter (NCC), aquaporin 3 (AQP3) and two isoforms of Na(+)/K(+)-ATPase (NKA α1a and NKA α1b) was higher than that of SW, BW or tidally-changing salinity fish. Gene expression of the Na(+)/K(+)/2Cl(-) cotransporter (NKCC1a), and the cystic fibrosis transmembrane conductance regulator (CFTR) were higher in fish in SW, BW or a tidally-changing salinity than in FW fish. Immunocytochemistry revealed that ionocytes of fish in tidally-changing salinities resemble ionocytes of SW fish. This study indicated that tilapia reared in a tidally-changing salinity can compensate for large changes in external osmolality while maintaining osmoregulatory parameters within a narrow range closer to that observed in SW-acclimated fish. Copyright © 2014 Elsevier Inc. All rights reserved.
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The shellfish enigma across the Mesolithic-Neolithic transition in southern Scandinavia
NASA Astrophysics Data System (ADS)
Lewis, J. P.; Ryves, D. B.; Rasmussen, P.; Olsen, J.; Knudsen, K.-L.; Andersen, S. H.; Weckström, K.; Clarke, A. L.; Andrén, E.; Juggins, S.
2016-11-01
The well-known and widespread replacement of oysters (abundant during the Mesolithic period) by cockles and mussels in many Danish Stone Age shell middens ca. 5900 cal yrs BP coincides with the transition to agriculture in southern Scandinavia. This human resource shift is commonly believed to reflect changing resource availability, driven by environmental and/or climatic change at the Mesolithic-Neolithic transition rather than cultural choice. While several hypotheses have been proposed to explain the ;Mesolithic-Neolithic oyster decline;, an explanation based on a sudden freshening of the inner Danish waters has received most attention. Here, for the first time, we test and refute this long-standing hypothesis that declining salinity explains the marked reduction in oysters identified within numerous shell middens across coastal Denmark at the Mesolithic-Neolithic transition using quantitative and qualitative salinity inference from several, independent proxies (diatoms, molluscs and foraminifera) from multiple Danish fjord sites. Alternatively, we attribute the oyster decline to other environmental causes (particularly changing sedimentation), ultimately driven by external climatic forcing. Critical application of such high-quality environmental archives can reinvigorate archaeological debates and can aid in understanding and managing environmental change in increasingly impacted coastal regions.
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Lowe, S E; Jain, M K; Zeikus, J G
1993-01-01
Anaerobic bacteria include diverse species that can grow at environmental extremes of temperature, pH, salinity, substrate toxicity, or available free energy. The first evolved archaebacterial and eubacterial species appear to have been anaerobes adapted to high temperatures. Thermoanaerobes and their stable enzymes have served as model systems for basic and applied studies of microbial cellulose and starch degradation, methanogenesis, ethanologenesis, acetogenesis, autotrophic CO2 fixation, saccharidases, hydrogenases, and alcohol dehydrogenases. Anaerobes, unlike aerobes, appear to have evolved more energy-conserving mechanisms for physiological adaptation to environmental stresses such as novel enzyme activities and stabilities and novel membrane lipid compositions and functions. Anaerobic syntrophs do not have similar aerobic bacterial counterparts. The metabolic end products of syntrophs are potent thermodynamic inhibitors of energy conservation mechanisms, and they require coordinated consumption by a second partner organism for species growth. Anaerobes adapted to environmental stresses and their enzymes have biotechnological applications in organic waste treatment systems and chemical and fuel production systems based on biomass-derived substrates or syngas. These kinds of anaerobes have only recently been examined by biologists, and considerably more study is required before they are fully appreciated by science and technology. Images PMID:8336675
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Environmental forcing on jellyfish communities in a small temperate estuary.
Primo, Ana Lígia; Marques, Sónia C; Falcão, Joana; Crespo, Daniel; Pardal, Miguel A; Azeiteiro, Ulisses M
2012-08-01
The impact of biological, hydrodynamic and large scale climatic variables on the jellyfish community of Mondego estuary was evaluated from 2003 to 2010. Plankton samples were collected at the downstream part of the estuary. Siphonophora Muggiaea atlantica and Diphyes spp. were the main jellyfish species. Jellyfish density was generally higher in summer and since 2005 densities had increased. Summer community analysis pointed out Acartia clausi, estuarine temperature and salinity as the main driven forces for the assemblage's structure. Also, Chl a, estuarine salinity, runoff and SST were identified as the major environmental factors influencing the siphonophores summer interannual variability. Temperature influenced directly and indirectly the community and fluctuation of jellyfish blooms in the Mondego estuary. This study represents a contribution to a better knowledge of the gelatinous plankton communities in small temperate estuaries. Copyright © 2012 Elsevier Ltd. All rights reserved.
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Fagnano, Massimo; Maggio, Albino
2018-03-01
The main environmental stresses of Italian croplands are discussed in relation to their interactions with ozone effects on crops. Water deficit and salinization are frequent in Mediterranean environments during spring-summer causing a decrease of soil water potential and water uptake by roots and consequently stomatal closure. These stresses also stimulate secondary metabolism and antioxidant accumulation, which also serves as a stress protection mechanism. High concentrations of tropospheric ozone are common all over Italy during the spring-summer season. Ozone injuries to vegetation are related to its penetration into plant tissues, mostly via stomatal uptake, rather than to tropospheric concentrations per se. In several crops, closure of stomata due to drought/salinization reduces ozone entering into leaf tissues and counteracts possible ozone damages. Furthermore, the stimulation of antioxidant synthesis as a response to environmental stresses can represent a further protection factor from ozone injuries for Mediterranean crops.The co-existence of stress-induced stomatal closure and high ozone levels during spring-summer in Mediterranean environments implies that models that do not take into account physiological responses of crops to drought and salinity stress may overestimate ozone damages when stress responses overlap with seasonal ozone peaks. The shift from concentration-based to flux-based approaches has improved the accuracy of models to assess ozone effects on agricultural crops. It is, however, necessary to further refine the flux concept with respect to the plant abiotic stress defense capacity that can differ among genotypes, climatic conditions, and physiological states.
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Daniels, Miles E; Hogan, Jennifer; Smith, Woutrina A; Oates, Stori C; Miller, Melissa A; Hardin, Dane; Shapiro, Karen; Los Huertos, Marc; Conrad, Patricia A; Dominik, Clare; Watson, Fred G R
2014-09-15
Cryptosporidium parvum, Giardia lamblia, and Toxoplasma gondii are waterborne protozoal pathogens distributed worldwide and empirical evidence suggests that wetlands reduce the concentrations of these pathogens under certain environmental conditions. The goal of this study was to evaluate how protozoal removal in surface water is affected by the water temperature, turbidity, salinity, and vegetation cover of wetlands in the Monterey Bay region of California. To examine how protozoal removal was affected by these environmental factors, we conducted observational experiments at three primary spatial scales: settling columns, recirculating wetland mesocosm tanks, and an experimental research wetland (Molera Wetland). Simultaneously, we developed a protozoal transport model for surface water to simulate the settling columns, the mesocosm tanks, and the Molera Wetland. With a high degree of uncertainty expected in the model predictions and field observations, we developed the model within a Bayesian statistical framework. We found protozoal removal increased when water flowed through vegetation, and with higher levels of turbidity, salinity, and temperature. Protozoal removal in surface water was maximized (~0.1 hour(-1)) when flowing through emergent vegetation at 2% cover, and with a vegetation contact time of ~30 minutes compared to the effects of temperature, salinity, and turbidity. Our studies revealed that an increase in vegetated wetland area, with water moving through vegetation, would likely improve regional water quality through the reduction of fecal protozoal pathogen loads. Copyright © 2014 Elsevier B.V. All rights reserved.
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Adaptive salinity management in the Murray-Darling Basin: a transaction cost study
NASA Astrophysics Data System (ADS)
Loch, A. J.
2017-12-01
Transaction costs hinder or promote effective management of common good resource intertemporal externalities. Appropriate policy choices may reduce externalities and improve social welfare, and transaction cost analysis can help to evaluate policy choices. However, without measurement of relevant transaction costs such policy evaluation remains challenging. This article uses a time series dataset of salinity management program to test theory aimed at transaction cost-based policy evaluation and adaptive resource management over a period of 30 years worth of data. We identify peaks and troughs in transaction costs over time, lag-effects in program expenditure, and calculate the decay in transaction cost impacts. We conclude that Australian salinity management programs are achieving flexible institutional outcomes and effective policy arrangements with long-term benefits. Proposed changes to the program moving forward add weight to our assertions of adaptive strategies, and illustrate the value of the novel data-driven tracnsaction cost analysis approach for other jurisdictions.
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Belcher, C.N.; Jennings, Cecil A.
2010-01-01
We examined the affects of selected water quality variables on the presence of subadult sharks in six of nine Georgia estuaries. During 231 longline sets, we captured 415 individuals representing nine species. Atlantic sharpnose shark (Rhizoprionodon terranovae), bonnethead (Sphyrna tiburo), blacktip shark (Carcharhinus limbatus) and sandbar shark (C. plumbeus) comprised 96.1% of the catch. Canonical correlation analysis (CCA) was used to assess environmental influences on the assemblage of the four common species. Results of the CCA indicated Bonnethead Shark and Sandbar Shark were correlated with each other and with a subset of environmental variables. When the species occurred singly, depth was the defining environmental variable; whereas, when the two co-occurred, dissolved oxygen and salinity were the defining variables. Discriminant analyses (DA) were used to assess environmental influences on individual species. Results of the discriminant analyses supported the general CCA findings that the presence of bonnethead and sandbar shark were the only two species that correlated with environmental variables. In addition to depth and dissolved oxygen, turbidity influenced the presence of sandbar shark. The presence of bonnethead shark was influenced primarily by salinity and turbidity. Significant relationships existed for both the CCA and DA analyses; however, environmental variables accounted for <16% of the total variation in each. Compared to the environmental variables we measured, macrohabitat features (e.g., substrate type), prey availability, and susceptibility to predation may have stronger influences on the presence and distribution of subadult shark species among sites.
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Gregório, Sílvia F; Carvalho, Edison S M; Encarnação, Sandra; Wilson, Jonathan M; Power, Deborah M; Canário, Adelino V M; Fuentes, Juan
2013-02-01
The processing of intestinal fluid, in addition to a high drinking rate, is essential for osmoregulation in marine fish. This study analyzed the long-term response of the sea bream (Sparus aurata L.) to relevant changes of external salinity (12, 35 and 55 p.p.t.), focusing on the anterior intestine and in the less-often studied rectum. Intestinal water absorption, epithelial HCO(3)(-) secretion and gene expression of the main molecular mechanisms (SLC26a6, SLC26a3, SLC4a4, atp6v1b, CFTR, NKCC1 and NKCC2) involved in Cl(-) and HCO(3)(-) movements were examined. The anion transporters SLC26a6 and SLC26a3 are expressed severalfold higher in the anterior intestine, while the expression of Atp6v1b (V-type H(+)-ATPase β-subunit) is severalfold higher in the rectum. Prolonged exposure to altered external salinity was without effect on water absorption but was associated with concomitant changes in intestinal fluid content, epithelial HCO(3)(-) secretion and salinity-dependent expression of SLC26a6, SLC26a3 and SLC4a4 in the anterior intestine. However, the most striking response to external salinity was obtained in the rectum, where a 4- to 5-fold increase in water absorption was paralleled by a 2- to 3-fold increase in HCO(3)(-) secretion in response to a salinity of 55 p.p.t. In addition, the rectum of high salinity-acclimated fish shows a sustained (and enhanced) secretory current (I(sc)), identified in vitro in Ussing chambers and confirmed by the higher expression of CFTR and NKCC1 and by immunohistochemical protein localization. Taken together, the present results suggest a functional anterior-posterior specialization with regard to intestinal fluid processing and subsequently to salinity adaptation of the sea bream. The rectum becomes more active at higher salinities and functions as the final controller of intestinal function in osmoregulation.
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Camacho-Jiménez, Laura; Díaz, Fernando; Sánchez-Castrejón, Edna; Ponce-Rivas, Elizabeth
2018-03-26
The Pacific white shrimp Litopenaeus vannamei is a euryhaline organism that copes with salinity fluctuations in the environment; therefore, its osmotic and ionic regulation abilities are vital. Osmoregulation may be controlled by the crustacean hyperglycemic hormone (CHH), a neuropeptide mainly expressed in the eyestalks. In L. vannamei, CHH-B1 and CHH-B2 are CHH isoforms isolated from the eyestalks whose expression is influenced by environmental salinity. It has been suggested that they are involved in the response to salinity stress. To clarify this, we investigated the effect of the recombinant peptides, rCHH-B1 and rCHH-B2, on the osmo-ionic regulation of shrimp acutely exposed to different salinity conditions (8, 26 and 45‰). Both rCHHs promoted differential effects on the osmoregulatory capacity (OC) and the ionoregulatory capacity (IC) for hemolymph Na + and Cl - during iso-osmotic (26‰) and hyper-osmotic (45‰) transfers. These changes were linked to the changes observed in Na + /K + ATPase and carbonic anhydrase gene expression in gills, especially under high salinity conditions, suggesting that the hormones may regulate the expression of these genes. Glucose and protein levels measured during acute salinity transfer suggest their roles as sources of metabolic energy for osmotic regulation or as organic osmolytes. These results taken together suggest that both the CHH-B1 and CHH-B2 peptides are important regulators of the physiological response of L. vannamei to acute salinity fluctuations.
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NASA Astrophysics Data System (ADS)
Linard, J.; Leib, K.; Colorado Water Science Center
2010-12-01
Elevated levels of salinity and dissolved selenium can detrimentally effect the quality of water where anthropogenic and natural uses are concerned. In areas, such as the lower Gunnison Basin of western Colorado, salinity and selenium are such a concern that control projects are implemented to limit their mobilization. To prioritize the locations in which control projects are implemented, multi-parameter regression models were developed to identify subbasins in the lower Gunnison River Basin that were most likely to have elevated salinity and dissolved selenium levels. The drainage area is about 5,900 mi2 and is underlain by Cretaceous marine shale, which is the most common source of salinity and dissolved selenium. To characterize the complex hydrologic and chemical processes governing constituent mobilization, geospatial variables representing 70 different environmental characteristics were correlated to mean seasonal (irrigation and nonirrigation seasons) salinity and selenium yields estimated at 154 sampling sites. The variables generally represented characteristics of the physical basin, precipitation, soil, geology, land use, and irrigation water delivery systems. Irrigation and nonirrigation seasons were selected due to documented effects of irrigation on constituent mobilization. Following a stepwise approach, combinations of the geospatial variables were used to develop four multi-parameter regression models. These models predicted salinity and selenium yield, within a 95 percent confidence range, at individual points in the Lower Gunnison Basin for irrigation and non-irrigation seasons. The corresponding subbasins were ranked according to their potential to yield salinity and selenium and rankings were used to prioritize areas that would most benefit from control projects.
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Combined effects of seawater acidification and salinity changes in Ruditapes philippinarum.
Velez, Catia; Figueira, Etelvina; Soares, Amadeu M V M; Freitas, Rosa
2016-07-01
Due to human activities, predictions for the coming years indicate increasing frequency and intensity of extreme weather events (rainy and drought periods) and pollution levels, leading to salinity shifts and ocean acidification. Therefore, several authors have assessed the effects of seawater salinity shifts and pH decrease on marine bivalves, but most of these studies evaluated the impacts of both factors independently. Since pH and salinity may act together in the environment, and their impacts may differ from their effects when acting alone, there is an urgent need to increase our knowledge when these environmental changes act in combination. Thus, the present study assessed the effects of seawater acidification and salinity changes, both acting alone and in combination, on the physiological (condition index, Na and K concentrations) and biochemical (oxidative stress related biomarkers) performance of Ruditapes philippinarum. For that, specimens of R. philippinarum were exposed for 28days to the combination of different pH levels (7.8 and 7.3) and salinities (14, 28 and 35). The results obtained showed that under control pH (7.8) and low salinity (14) the physiological status and biochemical performance of clams was negatively affected, revealing oxidative stress. However, under the same pH and at salinities 28 and 35 clams were able to maintain/regulate their physiological status and biochemical performance. Moreover, our findings showed that clams under low pH (7.3) and different salinities were able to maintain their physiological status and biochemical performance, suggesting that the low pH tested may mask the negative effects of salinity. Our results further demonstrated that, in general, at each salinity, similar physiological and biochemical responses were found in clams under both tested pH levels. Also, individuals under low pH (salinities 14, 28 and 25) and exposed to pH 7.8 and salinity 28 (control) tend to present a similar response pattern. These results indicate that pH may have a lower impact on clams than salinity. Thus, our findings point out that the predicted increase of CO2 in seawater and consequent seawater acidification will have fewer impacts on physiological and biochemical performance of R. philippinarum clams than salinity shifts. Copyright © 2016 Elsevier B.V. All rights reserved.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Bianchini, A.; Gilles, R.
1996-07-01
Synergism between mercury and salinity has been shown in invertebrates. Two authors have tied to correlate salinity effects with a higher or lower accumulation of mercury. Zauke, demonstrated lower mercury levels in several benthic invertebrates from limnic regions of the Elbe estuary when compared to those from Marine regions. On the other hand, Kendall did not report any significant difference in mercury concentrations in benthic macroinvertebrates throughout a salinity gradient in two estuaries from Georgia. In species hyperosmoregulating in diluted media, it could, however, be considered that the high water turnover would favor mercury accumulation. In this context, one couldmore » also expect a relationship between environmental salinity and mercury toxicity in different euryhaline species depending on their osmoregulatory capacities. We have tested this hypothesis analyzing the toxic effects and accumulation of mercury in three euryhaline crabs presenting different osmoregulatory capacities: Eriocheir sinensis (strong hyperosmoregulator), Carcinus maenas (weak hyperosmoregulator) and Cancer pagurus (osmoconformer). 16 refs., 4 figs., 1 tab.« less
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Increasing β-carotene content of phytoplankton Dunaliella salina using different salinity media
NASA Astrophysics Data System (ADS)
Hermawan, J.; Masithah, E. D.; Tjahjaningsih, W.; Abdillah, A. A.
2018-04-01
Dunaliella salina have got great attention in the nutritional, pharmaceutical and cosmetic companies because contain β-carotene. β-carotene functions as antioxidants and precursors of vitamin A and can treat tumors and cancer in humans. The content of β-carotene in D. salina can be increased by increasing salinity levels in the culture medium. The aim of this study was to determine whether increasing salinity may increas β-carotene content of phytoplankton D. salina. The research use data collection method with direct observation and then analyzed the result with descriptive method. The results showed that different salinity of media can influenced β-carotene content of D. salina. The highest β-carotene content of D. salina was at treatment B (30 ppt) which equal to 2.312 mg/L on 10th day. The production of β-carotene in D. salina can be increased was other environmental stress treatments in the form of stress-temperature, light and nutrients using.
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The ontogeny of tolerance curves: habitat quality vs. acclimation in a stressful environment.
Nougué, Odrade; Svendsen, Nils; Jabbour-Zahab, Roula; Lenormand, Thomas; Chevin, Luis-Miguel
2016-11-01
Stressful environments affect life-history components of fitness through (i) instantaneous detrimental effects, (ii) historical (carry-over) effects and (iii) history-by-environment interactions, including acclimation effects. The relative contributions of these different responses to environmental stress are likely to change along life, but such ontogenic perspective is often overlooked in studies of tolerance curves, precluding a better understanding of the causes of costs of acclimation, and more generally of fitness in temporally fine-grained environments. We performed an experiment in the brine shrimp Artemia to disentangle these different contributions to environmental tolerance, and investigate how they unfold along life. We placed individuals from three clones of A. parthenogenetica over a range of salinities during a week, before transferring them to a (possibly) different salinity for the rest of their lives. We monitored individual survival at repeated intervals throughout life, instead of measuring survival or performance at a given point in time, as commonly done in acclimation experiments. We then designed a modified survival analysis model to estimate phase-specific hazard rates, accounting for the fact that individuals may share the same treatment for only part of their lives. Our approach allowed us to distinguish effects of salinity on (i) instantaneous mortality in each phase (habitat quality effects), (ii) mortality later in life (history effects) and (iii) their interaction. We showed clear effects of early salinity on late survival and interactions between effects of past and current environments on survival. Importantly, analysis of the ontogenetic dynamics of the tolerance curve reveals that acclimation affects different parts of the curve at different ages. Adopting a dynamical view of the ontogeny of tolerance curve should prove useful for understanding niche limits in temporally changing environments, where the full sequence of environments experienced by an individual determines its overall environmental tolerance, and how it changes throughout life. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.
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Darnaude, Audrey M.; Sturrock, Anna; Trueman, Clive N.; Mouillot, David; EIMF; Campana, Steven E.; Hunter, Ewan
2014-01-01
Oxygen isotope ratios from fish otoliths are used to discriminate marine stocks and reconstruct past climate, assuming that variations in otolith δ18O values closely reflect differences in temperature history of fish when accounting for salinity induced variability in water δ18O. To investigate this, we exploited the environmental and migratory data gathered from a decade using archival tags to study the behaviour of adult plaice (Pleuronectes platessa L.) in the North Sea. Based on the tag-derived monthly distributions of the fish and corresponding temperature and salinity estimates modelled across three consecutive years, we first predicted annual otolith δ18O values for three geographically discrete offshore sub-stocks, using three alternative plausible scenarios for otolith growth. Comparison of predicted vs. measured annual δ18O values demonstrated >96% correct prediction of sub-stock membership, irrespective of the otolith growth scenario. Pronounced inter-stock differences in δ18O values, notably in summer, provide a robust marker for reconstructing broad-scale plaice distribution in the North Sea. However, although largely congruent, measured and predicted annual δ18O values of did not fully match. Small, but consistent, offsets were also observed between individual high-resolution otolith δ18O values measured during tag recording time and corresponding δ18O predictions using concomitant tag-recorded temperatures and location-specific salinity estimates. The nature of the shifts differed among sub-stocks, suggesting specific vital effects linked to variation in physiological response to temperature. Therefore, although otolith δ18O in free-ranging fish largely reflects environmental temperature and salinity, we counsel prudence when interpreting otolith δ18O data for stock discrimination or temperature reconstruction until the mechanisms underpinning otolith δ18O signature acquisition, and associated variation, are clarified. PMID:25279667
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Specialization of Bacillus in the Geochemically Challenged Environment of Death Valley
NASA Astrophysics Data System (ADS)
Kopac, S.
2014-04-01
Death Valley is the hottest, driest place in North America, a desert with soils containing toxic elements such as boron and lead. While most organisms are unable to survive under these conditions, a diverse community of bacteria survives here. What has enabled bacteria to adapt and thrive in a plethora of extreme and stressful environments where other organisms are unable to grow? The unique environmental adaptations that distinguish ecologically distinct bacterial groups (ecotypes) remain a mystery, in contrast to many animal species (perhaps most notably Darwin's ecologically distinct finch species). We resolve the ecological factors associated with recently diverged ecotypes of the soil bacteria Bacillus subtilis and Bacillus licheniformis, isolated from the dry, geochemically challenging soils of Death Valley, CA. To investigate speciation associated with challenging environmental parameters, we sampled soil transects along a 400m stretch that parallels a decrease in salinity adjacent to a salt flat; transects also encompass gradients in soil B, Cu, Fe, NO3, and P, all of which were quantified in our soil samples. We demarcated strains using Ecotype Simulation, a sequence-based algorithm. Each ecotype's habitat associations were determined with respect to salinity, B, Cu, Fe, NO3, and P. In addition, our sample strains were tested for tolerance of copper, boron and salinity (all known to inhibit growth at high concentrations) by comparing their growth over a 20 hour period. Ecotypes differed in their habitat associations with salinity, boron, copper, iron, and other ecological factors; these environmental dimensions are likely causing speciation of B. subtilis-licheniformis ecotypes at our sample site. Strains also differed in tolerance of boron and copper, providing evidence that our sequence-based demarcations reflect real differences in metabolism. By better understanding the relationship between bacterial speciation and the environment, we can begin to predict the habitability of unexplored extreme and extra-Earth environments.
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Sakai, Daniel M; Zornow, Kailee Anne; Campoy, Luis; Cable, Christina; Appel, Leslie D; Putnam, Holly J; Martin-Flores, Manuel
2018-01-01
Objectives We evaluated the use of rocuronium 0.3 mg/kg intravenously (IV) to facilitate tracheal intubation in cats anesthetized for elective ovariohysterectomy. Methods Thirty female cats were randomly allocated to receive rocuronium 0.3 mg/kg IV or an equal volume of normal saline, following induction of anesthesia with ketamine and midazolam. Thirty seconds after induction, a single investigator, unaware of treatment allocation, attempted tracheal intubation. The number of attempts and the time to complete intubation were measured. Intubating conditions were assessed as acceptable or unacceptable based on a composite score consisting of five different components. Duration of apnea after induction was measured and cases of hemoglobin desaturation (SpO 2 <90%) were identified. Results Intubation was completed faster (rocuronium 12 s [range 8-75 s]; saline 60 s [range 9-120 s]) and with fewer attempts (rocuronium 1 [range 1-2]; saline 2 [range 1-3], both P = 0.006) in cats receiving rocuronium. Unacceptable intubating conditions on the first attempt occurred in 3/15 cats with rocuronium and in 10/15 with saline ( P = 0.01). Apnea lasted 4 ± 1.6 mins with rocuronium and 2.3 ± 0.5 mins with saline ( P = 0.0007). No cases of desaturation were observed. Conclusions and relevance Rocuronium 0.3 mg/kg IV improves intubating conditions compared with saline and reduces the time and number of attempts to intubate with only a short period of apnea in cats.
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Kuperman, B I; Matey, V E
1999-12-22
Persistent fish infestation by the parasitic dinoflagellate Amyloodinium ocellatum was found at a highly saline lake, Salton Sea, California, USA. The seasonal dynamics of the infestation of young tilapia was traced in 1997-1998. First appearing in May, it became maximal in June-August, decreased in October and was not detectable in November. Outbreak of the infestation and subsequent mortality of young fish was registered at the Sea at a water temperature and salinity of 40 degrees C and 46 ppt, respectively. Some aspects of the ultrastructure of parasitic trophonts of A. ocellatum and their location on the fish from different size groups are considered. The interactions of parasitological and environmental factors and their combined effect upon fish from the Salton Sea are discussed.
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Lao, Xiaodong; Cheng, Congqian; Min, Xiaohua; Zhao, Jie; Zhou, Dayu; Li, Xiaogang
2015-11-01
The leaching behaviour of Sn and Pb elements from eutectic SnPb solder of electronic waste in acidic soil was investigated through acidification with HCl-H2SO4 solution and compared with saline solution. The amounts of Sn and Pb elements leached, when subjected to acidic soil, are higher than those with saline soil. Evidence for the significantly preferential release of Sn into the leachate is provided; the galvanic couple accelerated such preferential release. Surface product analysis reveals the slight damage of SnPb in saline soil. Serious dissolution due to electrochemical reaction and a thick, porous PbSO4 surface layer are observed in acidified soil, suggesting more severe toxicity potential of Pb in soil rather than in water.
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Turner, C.E.; Fishman, N.S.
1991-01-01
Recognition of alkaline, saline-lake deposits in the Morrison Formation significantly alters interpretations of depositional environments of this formation, and it also has important implications for paleoclimatic interpretation. Late Jurassic climate was apparently much more arid than had previously been thought. In fact, sedimentologic evidence suggests that the lake basin was typically dry for extended periods and enjoyed only brief wet intervals. This conclusion has important consequences for environmental interpretation of the habitat that was favorable for large herbivorous dinosaurs, which thrived in the Late Jurassic. -from Authors
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Epifauna and thermal additions in the upper Patuxent River estuary
Cory, R.L.; Nauman, J.W.
1969-01-01
In the upper Patuxent Estuary environmental changes in temperature, salinity, and turbidity over a 5-year period are linked to changes in epifaunal production and species distribution. During 1967 a series of monthly panels showed dry weight production averaged 2.8 times greater in a steam electric station heated effluent than in the intake. A downriver shift in epifanual production in 1967 and changes in species abundance was noted and attributed to natural changes in salinity and turbidity and man-induced changes in temperature. ?? 1969 Estuarine Research Federation.
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Hoy, Marshal; Boese, Bruce L.; Taylor, Louise; Reusser, Deborah; Rodriguez, Rusty
2012-01-01
In this study, we examine salinity stress tolerances of two populations of the invasive species New Zealand mud snail Potamopyrgus antipodarum, one population from a high salinity environment in the Columbia River estuary and the other from a fresh water lake. In 1996, New Zealand mud snails were discovered in the tidal reaches of the Columbia River estuary that is routinely exposed to salinity at near full seawater concentrations. In contrast, in their native habitat and throughout its spread in the western US, New Zealand mud snails are found only in fresh water ecosystems. Our aim was to determine whether the Columbia River snails have become salt water adapted. Using a modification of the standard amphipod sediment toxicity test, salinity tolerance was tested using a range of concentrations up to undiluted seawater, and the snails were sampled for mortality at daily time points. Our results show that the Columbia River snails were more tolerant of acute salinity stress with the LC50 values averaging 38 and 22 Practical Salinity Units for the Columbia River and freshwater snails, respectively. DNA sequence analysis and morphological comparisons of individuals representing each population indicate that they were all P. antipodarum. These results suggest that this species is salt water adaptable and in addition, this investigation helps elucidate the potential of this aquatic invasive organism to adapt to adverse environmental conditions.
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Effects of osmotic stress on predation behaviour of Asterias rubens L.
NASA Astrophysics Data System (ADS)
Agüera, Antonio; Schellekens, Tim; Jansen, Jeroen M.; Smaal, Aad C.
2015-05-01
Environmental stress plays an important role in determining ecosystem functioning and structure. In estuarine areas both tidal and seasonal salinity changes may cause osmotic stress on predators, affecting their behaviour and survival. The interaction between these predators and their prey may affect performance, thus influencing predator impact on prey populations. The common starfish, Asterias rubens, inhabits estuarine areas, such as the Dutch Wadden Sea, that exhibit large seasonal variation in salinity (10-32 PSU). In those areas A. rubens exerts top down control on its prey, thus representing an important shellfish predator. This predation may impact on cultured and natural shellfish populations. However, the effects of osmotic stress on A. rubens performance may influence its effect on prey. Although the effect of salinity in A. rubens survival has been extensively studied, the impact on its predation behaviour and acclimation capacity remains unclear. In this study, we analyse the performance of A. rubens preying on mussels (Mytilus edulis) after a salinity decrease and monitor its acclimation capacity over a period of 22 days. Our experiments demonstrated that salinity affected performance by reducing feeding activity and altering size prey selection. Moreover, as acclimation occurred, A. rubens predation performance improved in all sub-lethal treatments. We conclude that osmotic stress caused by decreasing salinity potentially influences A. rubens distribution, abundance, and potential impact on prey populations. However the magnitude of the change in salinity (from 31 to a minimum of 10 PSU) and its timescale (3 weeks) mediate this effect.
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Gibbons, Taylor C; Metzger, David C H; Healy, Timothy M; Schulte, Patricia M
2017-05-01
Phenotypic plasticity is thought to facilitate the colonization of novel environments and shape the direction of evolution in colonizing populations. However, the relative prevalence of various predicted patterns of changes in phenotypic plasticity following colonization remains unclear. Here, we use a whole-transcriptome approach to characterize patterns of gene expression plasticity in the gills of a freshwater-adapted and a saltwater-adapted ecotype of threespine stickleback (Gasterosteus aculeatus) exposed to a range of salinities. The response of the gill transcriptome to environmental salinity had a large shared component common to both ecotypes (2159 genes) with significant enrichment of genes involved in transmembrane ion transport and the restructuring of the gill epithelium. This transcriptional response to freshwater acclimation is induced at salinities below two parts per thousand. There was also differentiation in gene expression patterns between ecotypes (2515 genes), particularly in processes important for changes in the gill structure and permeability. Only 508 genes that differed between ecotypes also responded to salinity and no specific processes were enriched among this gene set, and an even smaller number (87 genes) showed evidence of changes in the extent of the response to salinity acclimation between ecotypes. No pattern of relative expression dominated among these genes, suggesting that neither gains nor losses of plasticity dominated the changes in expression patterns between the ecotypes. These data demonstrate that multiple patterns of changes in gene expression plasticity can occur following colonization of novel habitats. © 2017 John Wiley & Sons Ltd.
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ERIC Educational Resources Information Center
Langsford, Simon; Meredith, Steve; Munday, Bruce
2002-01-01
Presents science activities that mirror real life issues relating to plants and sustainability. Describes how to turn seed growing activities into an environmental simulation. Discusses the advantages of cross-curriculum learning opportunities. Includes student references and notes for teachers. (KHR)
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Dugan, Hilary A; Bartlett, Sarah L; Burke, Samantha M; Doubek, Jonathan P; Krivak-Tetley, Flora E; Skaff, Nicholas K; Summers, Jamie C; Farrell, Kaitlin J; McCullough, Ian M; Morales-Williams, Ana M; Roberts, Derek C; Ouyang, Zutao; Scordo, Facundo; Hanson, Paul C; Weathers, Kathleen C
2017-04-25
The highest densities of lakes on Earth are in north temperate ecosystems, where increasing urbanization and associated chloride runoff can salinize freshwaters and threaten lake water quality and the many ecosystem services lakes provide. However, the extent to which lake salinity may be changing at broad spatial scales remains unknown, leading us to first identify spatial patterns and then investigate the drivers of these patterns. Significant decadal trends in lake salinization were identified using a dataset of long-term chloride concentrations from 371 North American lakes. Landscape and climate metrics calculated for each site demonstrated that impervious land cover was a strong predictor of chloride trends in Northeast and Midwest North American lakes. As little as 1% impervious land cover surrounding a lake increased the likelihood of long-term salinization. Considering that 27% of large lakes in the United States have >1% impervious land cover around their perimeters, the potential for steady and long-term salinization of these aquatic systems is high. This study predicts that many lakes will exceed the aquatic life threshold criterion for chronic chloride exposure (230 mg L -1 ), stipulated by the US Environmental Protection Agency (EPA), in the next 50 y if current trends continue.
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Avia, Komlan; Coelho, Susana M.; Montecinos, Gabriel J.; Cormier, Alexandre; Lerck, Fiona; Mauger, Stéphane; Faugeron, Sylvain; Valero, Myriam; Cock, J. Mark; Boudry, Pierre
2017-01-01
Deciphering the genetic architecture of adaptation of brown algae to environmental stresses such as temperature and salinity is of evolutionary as well as of practical interest. The filamentous brown alga Ectocarpus sp. is a model for the brown algae and its genome has been sequenced. As sessile organisms, brown algae need to be capable of resisting the various abiotic stressors that act in the intertidal zone (e.g. osmotic pressure, temperature, salinity, UV radiation) and previous studies have shown that an important proportion of the expressed genes is regulated in response to hyposaline, hypersaline or oxidative stress conditions. Using the double digest RAD sequencing method, we constructed a dense genetic map with 3,588 SNP markers and identified 39 QTLs for growth-related traits and their plasticity under different temperature and salinity conditions (tolerance to high temperature and low salinity). GO enrichment tests within QTL intervals highlighted membrane transport processes such as ion transporters. Our study represents a significant step towards deciphering the genetic basis of adaptation of Ectocarpus sp. to stress conditions and provides a substantial resource to the increasing list of tools generated for the species. PMID:28256542
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Sanabria, Eduardo; Quiroga, Lorena; Vergara, Cristina; Banchig, Mariana; Rodriguez, Cesar; Ontivero, Emanuel
2018-05-01
Rhinella spinulosa is distributed from Peru to Argentina (from 1200 to 5000 m elevation), inhabiting arid mountain valleys of the Andes, characterized by salty soils. The variations in soil salinity, caused by high evapotranspiration of water, can create an osmotic constraint and high thermal oscillations for metamorphsed Andean toad (R. spinulosa), affecting their thermoregulation and extreme thermal tolerances. We investigated the changes in thermal tolerance parameters (critical thermal maximum and crystallization temperature) of a population of metamorphosed R. spinulosa from the Monte Desert of San Juan, Argentina, under different substrate salinity conditions. Our results suggest that the locomotor performance of metamorphs of R. spinulosa is affected by increasing salinity concentrations in the environment where they develop. On the other hand, the thermal extremes of metamorphs of R. spinulosa also showed changes associated with different salinity conditions. According to other studies on different organisms, the increase of the osmolarity of the internal medium may increase the thermal tolerance of this species. More studies are needed to understand the thermo-osmolar adjustments of the metamorphs of toads to environmental variability. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Two Fixed Ratio Dilutions for Soil Salinity Monitoring in Hypersaline Wetlands
Herrero, Juan; Weindorf, David C.; Castañeda, Carmen
2015-01-01
Highly soluble salts are undesirable in agriculture because they reduce yields or the quality of most cash crops and can leak to surface or sub-surface waters. In some cases salinity can be associated with unique history, rarity, or special habitats protected by environmental laws. Yet in considering the measurement of soil salinity for long-term monitoring purposes, adequate methods are required. Both saturated paste extracts, intended for agriculture, and direct surface and/or porewater salinity measurement, used in inundated wetlands, are unsuited for hypersaline wetlands that often are only occasionally inundated. For these cases, we propose the use of 1:5 soil/water (weight/weight) extracts as the standard for expressing the electrical conductivity (EC) of such soils and for further salt determinations. We also propose checking for ion-pairing with a 1:10 or more diluted extract in hypersaline soils. As an illustration, we apply the two-dilutions approach to a set of 359 soil samples from saline wetlands ranging in ECe from 2.3 dS m-1 to 183.0 dS m-1. This easy procedure will be useful in survey campaigns and in the monitoring of soil salt content. PMID:26001130
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Two fixed ratio dilutions for soil salinity monitoring in hypersaline wetlands.
Herrero, Juan; Weindorf, David C; Castañeda, Carmen
2015-01-01
Highly soluble salts are undesirable in agriculture because they reduce yields or the quality of most cash crops and can leak to surface or sub-surface waters. In some cases salinity can be associated with unique history, rarity, or special habitats protected by environmental laws. Yet in considering the measurement of soil salinity for long-term monitoring purposes, adequate methods are required. Both saturated paste extracts, intended for agriculture, and direct surface and/or porewater salinity measurement, used in inundated wetlands, are unsuited for hypersaline wetlands that often are only occasionally inundated. For these cases, we propose the use of 1:5 soil/water (weight/weight) extracts as the standard for expressing the electrical conductivity (EC) of such soils and for further salt determinations. We also propose checking for ion-pairing with a 1:10 or more diluted extract in hypersaline soils. As an illustration, we apply the two-dilutions approach to a set of 359 soil samples from saline wetlands ranging in ECe from 2.3 dS m(-1) to 183.0 dS m(-1). This easy procedure will be useful in survey campaigns and in the monitoring of soil salt content.
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Environmental control on early life stages of flatfishes in the Lima Estuary (NW Portugal)
NASA Astrophysics Data System (ADS)
Ramos, Sandra; Ré, Pedro; Bordalo, Adriano A.
2009-06-01
Several flatfishes spawn in oceanic waters and pelagic larvae are transported inshore to settle in the nursery areas, usually estuaries, where they remain during their juvenile life. Nursery areas appear as extremely important habitats, not only for juveniles but also for the earlier planktonic larval fish. Yet, the majority of nursery studies tend to focus only on one development stage, missing an integrative approach of the entire early life that fishes spent within a nursery ground. Thus, the present study assessed the influence of environmental parameters on the dynamics of the larval and juvenile flatfishes, throughout their nursery life in the Lima Estuary. Between April 2002 and April 2004, fortnightly subsurface ichthyoplankton samples were collected and juveniles were collected from October 2003 until September 2005. Larval assemblages comprised nine flatfish species, while only six were observed among the juvenile assemblages. Solea senegalensis and Platichthys flesus were the most abundant species of both fractions of the Lima Estuary flatfishes. Larval flatfish assemblages varied seasonally, without relevant differences between lower and middle estuary. Platichthys flesus dominated the spring samples and summer and autumn periods were characterized by an increase of overall abundance and diversity of larval flatfishes, mainly S. senegalensis, associated with temperature increase and reduced river flow. On the contrary, during the winter abundance sharply decreased, as a consequence of higher river run-off that might compromised the immigration of incompetent marine larvae. Juvenile flatfishes were more abundant in the middle and upper areas of the estuary, but the species richness was higher near the river mouth. Sediment type, distance from the river mouth, salinity, temperature and dissolved oxygen were identified as the main environmental factors structuring the juvenile flatfish assemblages. Juveniles were spatially discrete, with the most abundant species S. senegalensis and P. flesus associated with the middle and upper estuary, while the remaining species were associated with the lower estuarine areas. The larval fraction exhibited distinct dynamics from the juvenile estuarine flatfish community. Larval flatfishes showed a strong seasonal structure mainly regulated by biological features as the spawning season and also by seasonal variations of water characteristics. On the other hand, juvenile flatfishes were markedly controlled by site specific characteristics such as sediments structure, distance from the river mouth and salinity regime. The present study emphasized the idea that the environmental control varies throughout the ontogenetic development, stressing the importance of integrating all the early life of a species in flatfish nursery studies.
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Sinha, Amit Kumar; Rasoloniriana, Rindra; Dasan, Antony Franklin; Pipralia, Nitin; Blust, Ronny; De Boeck, Gudrun
2015-03-01
We investigated the interactive effect of ammonia toxicity, salinity challenge and nutritional status on the ecophysiological performance of European sea bass (Dicentrarchus labrax). Fish were progressively acclimated to normal seawater (32ppt), to brackish water (20ppt and 10ppt) and to hyposaline water (2.5ppt). Following acclimation to different salinities for two weeks, fish were exposed to high environmental ammonia (HEA, 20mg/L ∼1.18mM representing 50% of 96h LC50 value for ammonia) for 12h, 48h, 84h and 180h, and were either fed (2% body weight) or fasted (unfed for 7 days prior to HEA exposure). Biochemical responses such as ammonia (Jamm) and urea excretion rate, plasma ammonia, urea and lactate, plasma ions (Na(+), Cl(-) and K(+)) and osmolality, muscle water content (MWC) and liver and muscle energy budget (glycogen, lipid and protein), as well as branchial Na(+)/K(+)-ATPase (NKA) and H(+)-ATPase activity, and branchial mRNA expression of NKA and Na(+)/K(+)/2Cl(-) co-transporter (NKCC1) were investigated in order to understand metabolic and ion- osmoregulatory consequences of the experimental conditions. During HEA, Jamm was inhibited in fasted fish at 10ppt, while fed fish were still able to excrete efficiently. At 2.5ppt, both feeding groups subjected to HEA experienced severe reductions and eventually a reversion in Jamm. Overall, the build-up of plasma ammonia in HEA exposed fed fish was much lower than fasted ones. Unlike fasted fish, fed fish acclimated to lower salinities (10ppt-2.5ppt) could maintain plasma osmolality, [Na(+)], [Cl(-)] and MWC during HEA exposure. Thus fed fish were able to sustain ion-osmotic homeostasis which was associated with a more pronounced up-regulation in NKA expression and activity. At 2.5ppt both feeding groups activated H(+)-ATPase. The expression of NKCC1 was down-regulated at lower salinities in both fed and fasted fish, but was upregulated within each salinity after a few days of HEA exposure. Though an increment in plasma lactate content and a decline in energy stores were noted for both feeding regimes, the effect was more severe in feed deprived fish. Overall, several different physiological processes were disturbed in fasted sea bass during HEA exposure while feeding alleviated adverse effects of high ammonia and salinity challenge. This suggests that low food availability can render fish more vulnerable to external ammonia, especially at reduced seawater salinities. Copyright © 2015 Elsevier B.V. All rights reserved.
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Validation Test Report for GDEM4
2010-08-19
standard deviations called the Generalized Digital Environmental Model ( GDEM ). The present document describes the development and evaluation of GDEM4...the newest version of GDEM . As part of the evaluation of GDEM4, comparisons are made in this report to GDEM3 and to four other ocean climatologies...depth climatology of temperature and salinity and their standard deviations called the Generalized Digital Environmental Model ( GDEM ). The history of
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Differences in salinity tolerance of genetically distinct Phragmites australis clones
Achenbach, Luciana; Eller, Franziska; Nguyen, Loc Xuan; Brix, Hans
2013-01-01
Different clones of the wetland grass Phragmites australis differ in their morphology and physiology, and hence in their ability to cope with environmental stress. We analysed the responses of 15 P. australis clones with distinct ploidy levels (PLs) (4n, 6n, 8n, 10n, 12n) and geographic origins (Romania, Russia, Japan, Czech Republic, Australia) to step-wise increased salinity (8, 16, 24, 32, 40, 56 and 72 ppt). Shoot elongation rate, photosynthesis and plant part-specific ion accumulation were studied in order to assess if traits associated with salinity tolerance can be related to the genetic background and the geographic origin of the clones. Salt stress affected all clones, but at different rates. The maximum height was reduced from 1860 mm in control plants to 660 mm at 40 ppt salinity. The shoot elongation rate of salt-exposed plants varied significantly between clones until 40 ppt salinity. The light-saturated photosynthesis rate (Pmax) was stimulated by a salinity of 8 ppt, but decreased significantly at higher salinities. The stomatal conductance (gs) and the transpiration rate (E) decreased with increasing salinity. Only three clones survived at 72 ppt salinity, although their rates of photosynthesis were strongly inhibited. The roots and basal leaves of the salt-exposed plants accumulated high concentrations of water-extractable Na+ (1646 and 1004 µmol g−1 dry mass (DM), respectively) and Cl− (1876 and 1400 µmol g−1 DM, respectively). The concentrations of water-extractable Mg2+ and Ca2+ were reduced in salt-exposed plants compared with controls. The variation of all the measured parameters was higher among clones than among PLs. We conclude that the salinity tolerance of distinct P. australis clones varies widely and can be partially attributed to their longitudinal geographic origin, but not to PL. Further investigation will help in improving the understanding of this species' salt tolerance mechanisms and their connection to genetic factors.
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Berg, Florian; Almeland, Oda W; Skadal, Julie; Slotte, Aril; Andersson, Leif; Folkvord, Arild
2018-01-01
Atlantic herring, Clupea harengus, have complex population structures. Mixing of populations is known, but the extent of connectivity is still unclear. Phenotypic plasticity results in divergent phenotypes in response to environmental factors. A marked salinity gradient occurs from Atlantic Ocean (salinity 35) into the Baltic Sea (salinity range 2-12). Herring from both habitats display phenotypic and genetic variability. To explore how genetic factors and salinity influence phenotypic traits like growth, number of vertebrae and otolith shape an experimental population consisting of Atlantic purebreds and Atlantic/Baltic F1 hybrids were incubated and co-reared at two different salinities, 16 and 35, for three years. The F1-generation was repeatedly sampled to evaluate temporal variation. A von Bertalanffy growth model indicated that reared Atlantic purebreds had a higher maximum length (26.2 cm) than Atlantic/Baltic hybrids (24.8 cm) at salinity 35, but not at salinity 16 (25.0 and 24.8 cm, respectively). In contrast, Atlantic/Baltic hybrids achieved larger size-at-age than the wild caught Baltic parental group. Mean vertebral counts and otolith aspect ratios were higher for reared Atlantic purebreds than Atlantic/Baltic hybrids, consistent with the differences between parental groups. There were no significant differences in vertebral counts and otolith aspect ratios between herring with the same genotype but raised in different salinities. A Canonical Analysis of Principal Coordinates was applied to analyze the variation in wavelet coefficients that described otolith shape. The first discriminating axis identified the differences between Atlantic purebreds and Atlantic/Baltic hybrids, while the second axis represented salinity differences. Assigning otoliths based on genetic groups (Atlantic purebreds vs. Atlantic/Baltic hybrids) yielded higher classification success (~90%) than based on salinities (16 vs. 35; ~60%). Our results demonstrate that otolith shape and vertebral counts have a significant genetic component and are therefore useful for studies on population dynamics and connectivity.
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Vein Graft Preservation Solutions, Patency, and Outcomes After Coronary Artery Bypass Graft Surgery
Harskamp, Ralf E.; Alexander, John H.; Schulte, Phillip J.; Brophy, Colleen M.; Mack, Michael J.; Peterson, Eric D.; Williams, Judson B.; Gibson, C. Michael; Califf, Robert M.; Kouchoukos, Nicholas T.; Harrington, Robert A.; Ferguson, T. Bruce; Lopes, Renato D.
2015-01-01
IMPORTANCE In vitro and animal model data suggest that intraoperative preservation solutions may influence endothelial function and vein graft failure (VGF) after coronary artery bypass graft (CABG) surgery. Clinical studies to validate these findings are lacking. OBJECTIVE To evaluate the effect of vein graft preservation solutions on VGF and clinical outcomes in patients undergoing CABG surgery. DESIGN, SETTING, AND PARTICIPANTS Data from the Project of Ex-Vivo Vein Graft Engineering via Transfection IV (PREVENT IV) study, a phase 3, multicenter, randomized, double-blind, placebo-controlled trial that enrolled 3014 patients at 107 US sites from August 1, 2002, through October 22, 2003, were used. Eligibility criteria for the trial included CABG surgery for coronary artery disease with at least 2 planned vein grafts. INTERVENTIONS Preservation of vein grafts in saline, blood, or buffered saline solutions. MAIN OUTCOMES AND MEASURES One-year angiographic VGF and 5-year rates of death, myocardial infarction, and subsequent revascularization. RESULTS Most patients had grafts preserved in saline (1339 [44.4%]), followed by blood (971 [32.2%]) and buffered saline (507 [16.8%]). Baseline characteristics were similar among groups. One-year VGF rates were much lower in the buffered saline group than in the saline group (patient-level odds ratio [OR], 0.59 [95% CI, 0.45-0.78; P < .001]; graft-level OR, 0.63 [95% CI, 0.49-0.79; P < .001]) or the blood group (patient-level OR, 0.62 [95% CI, 0.46-0.83; P = .001]; graft-level OR, 0.63 [95% CI, 0.48-0.81; P < .001]). Use of buffered saline solution also tended to be associated with a lower 5-year risk for death, myocardial infarction, or subsequent revascularization compared with saline (hazard ratio, 0.81 [95% CI, 0.64-1.02; P = .08]) and blood (0.81 [0.63-1.03; P = .09]) solutions. CONCLUSIONS AND RELEVANCE Patients undergoing CABG whose vein grafts were preserved in a buffered saline solution had lower VGF rates and trends toward better long-term clinical outcomes compared with patients whose grafts were preserved in saline- or blood-based solutions. PMID:25073921
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León Robles, A; Acedo Félix, E; Gomez-Gil, B; Quiñones Ramírez, E I; Nevárez-Martínez, M; Noriega-Orozco, L
2013-12-01
Members of the genus Vibrio are common in aquatic environments. Among them are V. cholerae, V. vulnificus, V. parahaemolyticus and V. mimicus. Several studies have shown that environmental factors, such as temperature, salinity, and dissolved oxygen, are involved in their epidemiology. Therefore, the main objective of this study is to determine if there is a correlation between the presence/amount of V. cholerae, V, vulnificus, V. parahaemolyticus and V. mimicus and the environmental conditions of the seawater off the coast of Guaymas, México. Quantification of all four pathogenic bacteria was performed using the most probable number method, and suspected colonies were identified by polymerase chain reaction (PCR). Correlations were found using principal component analysis. V. parahaemolyticus was the most abundant and widely distributed bacteria, followed by V. vulnificus, V. mimicus and V. cholerae. Positive correlations between V. parahaemolyticus, V. vulnificus and V. mimicus with temperature, salinity, electric conductivity, and total dissolved solids were found. The abundance of V. cholerae was mainly affected by the sampling site and not by physicochemical parameters.
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Catena, Cristiana; Verheyen, Nicolas D; Url-Michitsch, Marion; Kraigher-Krainer, Elisabeth; Colussi, GianLuca; Pilz, Stefan; Tomaschitz, Andreas; Pieske, Burkert; Sechi, Leonardo A
2016-03-01
Left ventricular hypertrophy (LVH) is an independent risk factor for cardiovascular morbidity in hypertension. Current evidence suggests a contribution to LVH of plasma aldosterone levels that are inappropriately elevated for the salt status. The aim of this study was to investigate whether inappropriate modulation of aldosterone production by a saline load is associated with left ventricular (LV) mass in hypertensive patients. In 90 hypertensive patients free of clinically relevant cardiovascular complications in whom secondary forms of hypertension were ruled out, we performed a standard intravenous saline load (0.9% NaCl, 2 l in 4 hours) with measurement of plasma aldosterone and active renin at baseline and end of infusion. Bi-dimensional echocardiography was performed for the assessment of cardiac morphology and function. LVH was present in 19% of patients who had significantly worse renal function and higher body mass, blood pressure, and plasma aldosterone levels measured both at baseline and after the saline load than patients without LVH. LV mass was directly related to age, body mass, systolic blood pressure, duration of hypertension, baseline, and post-saline load plasma aldosterone levels and inversely to glomerular filtration. Multivariate regression analysis showed independent correlation of LV mass with body mass, systolic blood pressure, and plasma aldosterone levels measured after intravenous saline load, but not at baseline. In patients with hypertension, aldosterone levels measured after intravenous saline load are related to LV mass independent of age, body mass, and blood pressure, suggesting that limited ability of salt to modulate aldosterone production could contribute to LVH. © American Journal of Hypertension, Ltd 2015. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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NASA Astrophysics Data System (ADS)
Wang, Deli; Yang, Zhiming; Wang, Ling; Sun, Wei
2015-04-01
Soil salinization is a serious environmental problem across the Eurasian steppes, where millions people have been living for at least five thousand years and will still depend on it in the near future. During the last several decades, ecologists and grassland scientists have done much research on rational grassland utilization avoiding land degradation and reduction in ecological services. Meanwhile, the central and local governments took some attempts of agricultural policy and ecological subsidy to mitigate large scale land salinization in Northeast China. Fortunately, more and more farmers and stakeholders begin to adopt rational grassland management with the guidance of scientists and the help of local governments. However, up to date, there is still a gap between farmers, scientists and governments, which often negatively affect grassland production and remission of soil salinization in these areas. We conducted a case study on sustainable grassland production adapted to steppe salinization funded by EC project from 2011 to 2013. Our goal is trying to establish a mode of adaptive grassland management integrating previous scientific knowledge (grazing and seeding), current agricultural policies (ecological subsidy) and stakeholders' participation or performance. The study showed that: A. Despite of some grassland utilization techniques available for stakeholders (regulating stocking rate and seeding in pastures, or planting high quality forages), they tended to take the simplest action to enhance animal production and prevent grassland salinization; B. Compared to educating or training stakeholders, demonstration of grazing management is the most effective mean for knowledge dissemination or technology transfer; C. Ecological subsidy is absolutely welcome to the local people, and technology transfer became easier when combined with ecological subsidy; D. There was a contrasting effect in grassland production and land degradation mitigation for experimental farm that integrated social policy and scientific knowledge with stakeholder participation; that is, the stakeholder had higher animal production without accelerating grassland salinization during the three experimental years. Furthermore, this case study suggested that the perception and participation of stakeholders play an important role in grassland management adapted to environmental changes, and it is possible for grassland management to effectively integrate society and science.
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Tang, Long; Wolf, Amelia A; Gao, Yang; Wang, Cheng Huan
2018-06-01
In an attempt to clarify the role of environmental and biotic interactions on plant growth, there has been a long-running ecological debate over whether the intensity and importance of competition stabilizes, increases or decreases across environmental gradients. We conducted an experiment in a Chinese estuary to investigate the effects of a non-resource stress gradient, soil salinity (from 1.4‰ to 19.0‰ salinity), on the competitive interactions between native Phragmites australis and invasive Spartina alterniflora. We linked these effects to measurements of photosynthetic activities to further elucidate the underlying physiological mechanism behind the competitive interactions and the driver of invasion. The experiments revealed that while biomass of both species decreased in the presence of the other, competition did not alter photosynthetic activity of either species over time. P. australis exhibited high photosynthetic activity, including low chlorophyllase activity, high chlorophyll content, high stomatal conductance and high net photosynthetic rate, at low salinity. Under these conditions, P. australis experienced low competitive intensity, leading to high biomass production and competitive exclusion of S. alterniflora. The opposite was observed for S. alterniflora: while competitive intensity experienced by P. australis increased with increasing salinity, and photosynthetic activity, biomass, competitive dominance and the importance of competition for P. australis growth decreased, those of S. alterniflora were stable. These findings demonstrate that S. alterniflora invasion driven by competitive exclusion are likely to occur and expand in high salinity zones. The change in the nature of competition along a non-resource stress gradient differs between competitors likely due to differences in photosynthetic tolerance to salinity. The driver of growth of the less-tolerant species changes from competition to non-resource stress factors with increasing stress levels, whereas competition is constantly important for growth of the more-tolerant species. Incorporating metrics of both competition intensity and importance, as well as linking these competitive outcomes with physiological mechanisms, is crucial to understanding, predicting, and mediating the effects of invasive species in the future. © 2018 by the Ecological Society of America.
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Hu, Lipan; Xiang, Lixia; Li, Shuting; Zou, Zhirong; Hu, Xiao-Hui
2016-04-01
Polyamines are important in protecting plants against various environmental stresses, including protection against photodamage to the photosynthetic apparatus. The molecular mechanism of this latter effect is not completely understood. Here, we have investigated the effects of salinity-alkalinity stress and spermidine (Spd) on tomato seedlings at both physiological and transcriptional levels. Salinity-alkalinity stress decreased leaf area, net photosynthetic rate, maximum net photosynthetic rate, light saturation point, apparent quantum efficiency, total chlorophyll, chlorophyll a and chlorophyll a:chlorophyll b relative to the control. The amount of D1 protein, an important component of photosystem II, was reduced compared with the control, as was the expression of psbA, which codes for D1. Expression of the chlorophyll biosynthesis gene porphobilinogen deaminase (PBGD) was reduced following salinity-alkalinity stress, whereas the expression of Chlase, which codes for chlorophyllase, was increased. These negative physiological effects of salinity-alkalinity stress were alleviated by exogenous Spd. Expression of PBGD and psbA were enhanced, whereas the expression of Chlase was reduced, when exogenous Spd was included in the stress treatment compared with when it was not. The protective effect of Spd on chlorophyll and D1 protein content during stress may maintain the photosynthetic apparatus, permitting continued photosynthesis and growth of tomato seedlings (Solanum lycopersicum cv. Jinpengchaoguan) under salinity-alkalinity stress. © 2015 Scandinavian Plant Physiology Society.
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NASA Astrophysics Data System (ADS)
Roethig, T.; Ochsenkuehn, M. A.; van der Merwe, R.; Roik, A.; Voolstra, C. R.
2016-02-01
Environmental change is expected to render the oceans more saline, but scleractinian corals are assumed to be stenohaline osmoconformers. Yet, some corals are able to tolerate salinities up to 50 PSU, but we know little about the mechanisms involved. Previous studies have exclusively addressed the coral host and their algal symbionts (Symbiodinium) in hospite. To disentangle the role of all compartments of the coral holobiont we assessed the response of the coral host, its symbiont algae in the genus Symbiodinium (in hospite and in culture), and the associated bacterial community to strongly increased salinities. In a short-term incubation (4h) we could measure decreases in the calcification rate of the coral host and the photosynthetic performance of its algal symbiont in hospite. In a long-term (29 days) setup we found no differences in the photosynthetic efficiency but a major restructuring of the bacterial communities. In four Symbiodinium cultures we identified changes in photosynthetic yields and osmolytes composition upon short-term salinity exposure (≤24h). Our results show a short-term reaction of coral host and Symbiodinium to strongly increased salinities. However, lack of an apparent physiological long-term response indicates an acclimation process that is accompanied by a microbiome community shift towards a microbiome that potentially supports increased osmolyte production. Furthermore, changes in osmolytes composition in the Symbiodinium cultures display conserved osmoregulatory processes that may translate to osmoregulation for the coral holobiont.
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La Peyre, M.K.; Casas, S.M.; Gayle, W.; La Peyre, Jerome F.
2010-01-01
Perkinsus marinus is a major cause of mortality in eastern oysters along the Gulf of Mexico and Atlantic coasts. It is also well documented that temperature and salinity are the primary environmental factors affecting P. marinus viability and proliferation. However, little is known about the effects of combined sub-optimal temperatures and salinities on P. marinus viability. This in vitro study examined those effects by acclimating P. marinus at three salinities (7, 15, 25. ppt) to 10 ??C to represent the lowest temperatures generally reached in the Gulf of Mexico, and to 2 ??C to represent the lowest temperatures reached along the mid-Atlantic coasts and by measuring changes in cell viability and density on days 1, 30, 60 and 90 following acclimation. Cell viability and density were also measured in 7. ppt cultures acclimated to each temperature and then transferred to 3.5. ppt. The largest decreases in cell viability occurred only with combined low temperature and salinity, indicating that there is clearly a synergistic effect. The largest decreases in cell viability occurred only with both low temperature and salinity after 30. days (3.5. ppt, 2 ??C: 0% viability), 60. days (3.5. ppt, 10 ??C: 0% viability) and 90. days (7. ppt, 2 ??C: 0.6 ?? 0.7%; 7. ppt, 10 ??C: 0.2 ?? 0.2%). ?? 2010 .
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Flores, Pilar; Hernández, Virginia; Hellín, Pilar; Fenoll, Jose; Cava, Juana; Mestre, Teresa; Martínez, Vicente
2016-03-30
The dwarf tomato variety Micro-Tom has been used as a plant model for studies of plant development. However, its response to environmental and agricultural factors has not been well studied. This work studies the phytochemical content of Micro-Tom tomato and its comparative response to saline and nutritional (N, K and Ca) stresses with regard to a commercial variety. The chromatographic profiles of Micro-Tom were similar to those of the commercial variety and the only differences appear to be the concentration of the components. In Micro-Tom, the concentrations of sugars and organic acids increased by salinity in a lesser extent than in Optima. Moreover, contrary to that observed in the commercial variety, phenolic compounds and vitamin C did not increase by salinity in the dwarf variety. However, both varieties increased similarly the concentrations of carotenoids under saline conditions. Finally, fruit yield and most primary and secondary metabolite concentrations in Micro-Tom were not affected by N, K or Ca limitation. The mutations leading to the dwarf phenotype did not greatly alter the metabolite profiles but studies using Micro-Tom as a plant model should consider the lower capacity for sugars and organic acids under saline conditions and the greater tolerance to nutrient limitation of the dwarf variety. © 2015 Society of Chemical Industry.
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Dunaliella spp. Under Environmental Stress: Enhancing Lipid Production and Optimizing Harvest
NASA Astrophysics Data System (ADS)
Mixson, Stephanie Marie
Agricultural crops including corn, sugar cane, and oil palm have been investigated as potential sources for biofuel; however, they produce only a fraction of the oil percent biomass as compared to that of microalgae. Growth and lipid production by microalgae is regulated by a variety of environmental factors, including light intensity, availability of nutrients, temperature regime and salinity. We assessed 14 strains of the saltwater algae Dunaliella spp. (Teodoresco) in unialgal cultures within four species to determine a best strain or strain(s) as potential feedstock for biofuels. The taxonomy of these 14 strains was elucidated by comparing both physiological characteristics and the ITS2 and 18S regions. After careful analysis, the data suggest that the 14 strains grouped within four species: D. tertiolecta, D. pseudosalina, D. salina, and D. viridis. In addition, the isolation and accurate quantification of neutral lipids in Dunaliella was developed from existing techniques. Nile Red was optimized as a qualitative stain to rapidly screen and visualize neutral lipids. Direct transesterification was determined to be the best quantitative method because it yielded high amounts of neutral lipids with precise and reproducible results when compared to conventional extraction methods. Seven strains were selected for further efforts to enhance lipid production using salinity stress, nutrient limitation, pH stress, continuous light, and bubbling with carbon dioxide (CO2). High salinity yielded the maximum total fatty acid (FA) content (up to 65% by dry weight) in comparison to controls (˜10-25% total FAs). High pH x low salinity, low pH, and continuous light x CO2 yielded near maximum FA content (56%, 43%, and 42%, respectively). Nitrogen and/or phosphorus limitation and 12:12 (light:dark photoperiod) x CO 2 did not significantly enhance FA production (23% and 31%, respectively). Results were strain-specific with high intraspecific variation observed within each environmental stressor. Glycerol production, a known mechanism of osmoregulation in Dunaliella, was measured in a short-term salinity stress experiment and found to significantly increase 30 min to 24 hr after exposure. In addition, the glycerol biosynthesis gene, glycerol-3-phosphate dehydrogenase or GPDH, was significantly expressed 30 min to 2 hr in response to hyperosmotic stress. The data suggest that Dunaliella strains may incorporate a proportion of glycerol as triacylglycerol (TAG) under short-term, high-salinity stress. High lipid-producing strains were grown in mass culture, but at this time the commercialization of harvesting has not been proven economically feasible. Autoflocculation, electro-flocculation, and hollow-fiber filtration were compared as potential harvesting mechanisms for the mass culture of Dunaliella spp. Hollow-fiber filtration (>99% biomass recovery) as harvesting mechanism offers many attractive advantages (i.e. reuse of filtrate as culture medium) when compared to auto-flocculation and indirect electroflocculation (>95% biomass recovery). This research provides evidence that Dunaliella can be used as a source of biofuel because these strains can be mass-cultured; their lipids enhanced through a simple high-salinity adjustment; and commercially harvested.
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Moscatiello, Roberto; Sello, Simone; Novero, Mara; Negro, Alessandro; Bonfante, Paola; Navazio, Lorella
2014-08-01
Arbuscular mycorrhiza (AM) is an ecologically relevant symbiosis between most land plants and Glomeromycota fungi. The peculiar traits of AM fungi have so far limited traditional approaches such as genetic transformation. The aim of this work was to investigate whether the protein transduction domain of the HIV-1 transactivator of transcription (TAT) protein, previously shown to act as a potent nanocarrier for macromolecule delivery in both animal and plant cells, may translocate protein cargoes into AM fungi. We evaluated the internalization into germinated spores of Gigaspora margarita of two recombinant TAT fusion proteins consisting of either a fluorescent (GFP) or a luminescent (aequorin) reporter linked to the TAT peptide. Both TAT-fused proteins were found to enter AM fungal mycelia after a short incubation period (5-10 min). Ca2+ measurements in G. margarita mycelia pre-incubated with TAT-aequorin demonstrated the occurrence of changes in the intracellular free Ca2+ concentration in response to relevant stimuli, such as touch, cold, salinity, and strigolactones, symbiosis-related plant signals. These data indicate that the cell-penetrating properties of the TAT peptide can be used as an effective strategy for intracellularly delivering proteins of interest and shed new light on Ca2+ homeostasis and signalling in AM fungi. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.
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Saline sewage treatment and source separation of urine for more sustainable urban water management.
Ekama, G A; Wilsenach, J A; Chen, G H
2011-01-01
While energy consumption and its associated carbon emission should be minimized in wastewater treatment, it has a much lower priority than human and environmental health, which are both closely related to efficient water quality management. So conservation of surface water quality and quantity are more important for sustainable development than green house gas (GHG) emissions per se. In this paper, two urban water management strategies to conserve fresh water quality and quantity are considered: (1) source separation of urine for improved water quality and (2) saline (e.g. sea) water toilet flushing for reduced fresh water consumption in coastal and mining cities. The former holds promise for simpler and shorter sludge age activated sludge wastewater treatment plants (no nitrification and denitrification), nutrient (Mg, K, P) recovery and improved effluent quality (reduced endocrine disruptor and environmental oestrogen concentrations) and the latter for significantly reduced fresh water consumption, sludge production and oxygen demand (through using anaerobic bioprocesses) and hence energy consumption. Combining source separation of urine and saline water toilet flushing can reduce sewer crown corrosion and reduce effluent P concentrations. To realize the advantages of these two approaches will require significant urban water management changes in that both need dual (fresh and saline) water distribution and (yellow and grey/brown) wastewater collection systems. While considerable work is still required to evaluate these new approaches and quantify their advantages and disadvantages, it would appear that the investment for dual water distribution and wastewater collection systems may be worth making to unlock their benefits for more sustainable urban development.
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A pilot study of the validation of percutaneous testing in cats.
Rossi, Michael A; Messinger, Linda; Olivry, Thierry; Hoontrakoon, Raweewan
2013-10-01
Intradermal testing is useful for the identification of environmental allergens to which cats could be hypersensitive; intradermal test reactions are often subtle and difficult to interpret in cats. Percutaneous testing is the standard technique for the detection of significant environmental allergens in people, but it has not yet been evaluated in cats with hypersensitivity dermatitis. The purpose of this study was to evaluate and compare the skin test responses of healthy cats to percutaneous application and intradermal injections of control solutions. Ten clinically healthy cats were studied. Percutaneous applications of 0.0275 and 0.1 mg/mL aqueous histamine, 6 mg/mL glycerinated histamine, 0.9% buffered saline and 50% glycerosaline solution were performed using Greer Pick (Greer Laboratories, Lenoir, NC, USA) and Duotip-Test II (Lincoln Diagnostics, Decatur, IL, USA) percutaneous applicators. Reactions were compared with intradermal injections of 0.0275 mg/mL aqueous histamine and 0.9% buffered saline as controls. Positive responses to histamine solutions were significantly greater with the Greer Pick than with the Duotip-Test II. There were no significant differences between the histamine reactions using the Greer Pick applicator and the intradermal injections. Percutaneous reactions to histamine were more well demarcated and easier to read than intradermal injection reactions. Reactions to the saline controls were not noted. Percutaneous application of 6 mg/mL glycerinated histamine solution, 50% glycerosaline solution and 0.9% buffered saline produced similar positive and negative control wheals. These observations warrant further studies of percutaneous allergen testing in cats with hypersensitivity dermatitis. © 2013 ESVD and ACVD.
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Campbell, Barbara J; Kirchman, David L
2013-01-01
Very little is known about growth rates of individual bacterial taxa and how they respond to environmental flux. Here, we characterized bacterial community diversity, structure and the relative abundance of 16S rRNA and 16S rRNA genes (rDNA) using pyrosequencing along the salinity gradient in the Delaware Bay. Indices of diversity, evenness, structure and growth rates of the surface bacterial community significantly varied along the transect, reflecting active mixing between the freshwater and marine ends of the estuary. There was no positive correlation between relative abundances of 16S rRNA and rDNA for the entire bacterial community, suggesting that abundance of bacteria does not necessarily reflect potential growth rate or activity. However, for almost half of the individual taxa, 16S rRNA positively correlated with rDNA, suggesting that activity did follow abundance in these cases. The positive relationship between 16S rRNA and rDNA was less in the whole water community than for free-living taxa, indicating that the two communities differed in activity. The 16S rRNA:rDNA ratios of some typically marine taxa reflected differences in light, nutrient concentrations and other environmental factors along the estuarine gradient. The ratios of individual freshwater taxa declined as salinity increased, whereas the 16S rRNA:rDNA ratios of only some typical marine bacteria increased as salinity increased. These data suggest that physical and other bottom-up factors differentially affect growth rates, but not necessarily abundance of individual taxa in this highly variable environment. PMID:22895159
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Martinez-Urtaza, Jaime; Lozano-Leon, Antonio; Varela-Pet, Jose; Trinanes, Joaquin; Pazos, Yolanda; Garcia-Martin, Oscar
2008-01-01
Infections associated with Vibrio parahaemolyticus on the coast of Galicia (in northwestern Spain) were reported to be linked to large outbreaks of illness during 1999 and 2000. Little information is available about the ecological factors that influence the emergence of V. parahaemolyticus infections in this temperate region. We carried out a 3-year study to investigate the occurrence and distribution of V. parahaemolyticus at 26 sites located in the four main rias of Galicia in association with environmental and oceanographic variables. V. parahaemolyticus was detected in all the areas investigated and throughout the complete period of study with an overall incidence of 12.5%. Salinity was the primary factor governing the temporal and spatial distribution of V. parahaemolyticus, whereas seawater temperature had a secondary effect and only modulated the abundance in periods and areas of reduced salinities. Higher occurrence of V. parahaemolyticus was observed during periods of lower salinity in autumn, with a total of 61 positive samples (18%) and a mean density of 1,234 most probable number/100 g. V. parahaemolyticus was primarily detected in areas of reduced salinity close to freshwater discharge points, where it was found in up to 45% of the samples. Characterization of the isolates obtained from the study resulted in the first identification of two pathogenic tdh-positive strains of V. parahaemolyticus recovered from the marine environment in Galicia. These isolates showed serotypes identical to and DNA profiles indistinguishable from those of the clinical clone of V. parahaemolyticus dominant in infections in Spain in the last 10 years. PMID:17981951
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Hu, Anyi; Liu, Xiaobo; Chen, Feng; Yao, Tandong; Jiao, Nianzhi
2014-01-01
The phylogenetic diversity of picocyanobacteria in seven alkaline lakes on the Tibetan Plateau was analyzed using the molecular marker 16S-23S rRNA internal transcribed spacer sequence. A total of 1,077 environmental sequences retrieved from the seven lakes were grouped into seven picocyanobacterial clusters, with two clusters newly described here. Each of the lakes was dominated by only one or two clusters, while different lakes could have disparate communities, suggesting low alpha diversity but high beta diversity of picocyanobacteria in these high-altitude freshwater and saline lakes. Several globally distributed clusters were found in these Tibetan lakes, such as subalpine cluster I and the Cyanobium gracile cluster. Although other clusters likely exhibit geographic restriction to the plateau temporally, reflecting endemicity, they can indeed be distributed widely on the plateau. Lakes with similar salinities may have similar genetic populations despite a large geographic distance. Canonical correspondence analysis identified salinity as the only environmental factor that may in part explain the diversity variations among lakes. Mantel tests suggested that the community similarities among lakes are independent of geographic distance. A portion of the picocyanobacterial clusters appear to be restricted to a narrow salinity range, while others are likely adapted to a broad range. A seasonal survey of Lake Namucuo across 3 years did not show season-related variations in diversity, and depth-related population partitioning was observed along a vertical profile of the lake. Our study emphasizes the high dispersive potential of picocyanobacteria and suggests that the regional distribution may result from adaptation to specified environments. PMID:25281375
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Remotely Sensed Data for High Resolution Agro-Environmental Policy Analysis
NASA Astrophysics Data System (ADS)
Welle, Paul
Policy analyses of agricultural and environmental systems are often limited due to data constraints. Measurement campaigns can be costly, especially when the area of interest includes oceans, forests, agricultural regions or other dispersed spatial domains. Satellite based remote sensing offers a way to increase the spatial and temporal resolution of policy analysis concerning these systems. However, there are key limitations to the implementation of satellite data. Uncertainty in data derived from remote-sensing can be significant, and traditional methods of policy analysis for managing uncertainty on large datasets can be computationally expensive. Moreover, while satellite data can increasingly offer estimates of some parameters such as weather or crop use, other information regarding demographic or economic data is unlikely to be estimated using these techniques. Managing these challenges in practical policy analysis remains a challenge. In this dissertation, I conduct five case studies which rely heavily on data sourced from orbital sensors. First, I assess the magnitude of climate and anthropogenic stress on coral reef ecosystems. Second, I conduct an impact assessment of soil salinity on California agriculture. Third, I measure the propensity of growers to adapt their cropping practices to soil salinization in agriculture. Fourth, I analyze whether small-scale desalination units could be applied on farms in California in order mitigate the effects of drought and salinization as well as prevent agricultural drainage from entering vulnerable ecosystems. And fifth, I assess the feasibility of satellite-based remote sensing for salinity measurement at global scale. Through these case studies, I confront both the challenges and benefits associated with implementing satellite based-remote sensing for improved policy analysis.
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Pavlaki, Maria D; Morgado, Rui G; van Gestel, Cornelis A M; Calado, Ricardo; Soares, Amadeu M V M; Loureiro, Susana
2017-11-01
mMarine and estuarine ecosystems are highly productive areas that often act as a final sink for several pollutants, such as cadmium. Environmental conditions in these habitats can affect metal speciation, as well as its uptake and depuration by living organisms. The aim of this study was to assess cadmium uptake and depuration rates in the euryhaline calanoid copepod Acartia tonsa under different pH, salinity and temperature conditions. Cadmium speciation did not vary with changing pH or temperature, but varied with salinity. Free Cd 2+ ion activity increased with decreasing salinities resulting in increased cadmium concentrations in A. tonsa. However, uptake rate, derived using free Cd 2+ ion activity, showed no significant differences at different salinities indicating a simultaneous combined effect of Cd 2+ speciation and metabolic rates for osmoregulation. Cadmium concentration in A. tonsa and uptake rate increased with increasing pH, showing a peak at the intermediate pH of 7.5, while depuration rate fluctuated, thus suggesting that both parameters are mediated by metabolic processes (to maintain homeostasis at pH levels lower than normal) and ion competition at membrane binding sites. Cadmium concentration in A. tonsa, uptake and depuration rates increased with increasing temperature, a trend that can be attributed to an increase in metabolic energy demand at higher temperatures. The present study shows that cadmium uptake and depuration rates in the marine copepod A. tonsa is mostly affected by biological processes, mainly driven by metabolic mechanisms, and to a lesser extent by metal speciation in the exposure medium. Copyright © 2017 Elsevier Inc. All rights reserved.
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Merino, J.H.; Carter, J.; Merino, S.L.
2009-01-01
Distribution of marine submerged aquatic vegetation (SAV; i.e., seagrass) in the northern Gulf of Mexico coast has been documented, but there are nonmarine submersed or SAV species occurring in estuarine salinities that have not been extensively reported. We sampled 276 SAV beds along the gulf coast in Florida, Alabama, Mississippi, Louisiana, and Texas in 2001 and 2002 in oligohaline to polyhaline (0 to 36 parts per thousand) waters to determine estuarine SAV species distribution and identify mesohaline SAV communities. A total of 20 SAV and algal species was identified and habitat characteristics such as salinity, water depth, pH, conductivity, turbidity, dissolved oxygen, and sediment composition were collected. Fourteen SAV species occurred two or more times in our samples. The most frequently occurring species was Ruppia maritima L. (n = 148), occurring in over half of SAV beds sampled. Eleocharis sp. (n = 47), characterized with an emergent rather than submerged growth form, was a common genus in the SAV beds sampled. A common marine species was Halodule wrightii Asch. (n = 36). Nonindigenous species Myriophyllum spicatum L. (n = 31) and Hydrilla verticillata (L. f.) Royle (n = 6) were present only in oligohaline water. Analyzing species occurrence and environmental characteristics using canonical correspondence and two-way indicator species analysis, we identify five species assemblages distinguished primarily by salinity and depth. Our survey increases awareness of nonmarine SAV as a natural resource in the gulf, and provides baseline data for future research. ?? 2009 by the Marine Environmental Sciences Consortium of Alabama.
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Adaptation to Low Salinity Promotes Genomic Divergence in Atlantic Cod (Gadus morhua L.)
Berg, Paul R.; Jentoft, Sissel; Star, Bastiaan; Ring, Kristoffer H.; Knutsen, Halvor; Lien, Sigbjørn; Jakobsen, Kjetill S.; André, Carl
2015-01-01
How genomic selection enables species to adapt to divergent environments is a fundamental question in ecology and evolution. We investigated the genomic signatures of local adaptation in Atlantic cod (Gadus morhua L.) along a natural salinity gradient, ranging from 35‰ in the North Sea to 7‰ within the Baltic Sea. By utilizing a 12 K SNPchip, we simultaneously assessed neutral and adaptive genetic divergence across the Atlantic cod genome. Combining outlier analyses with a landscape genomic approach, we identified a set of directionally selected loci that are strongly correlated with habitat differences in salinity, oxygen, and temperature. Our results show that discrete regions within the Atlantic cod genome are subject to directional selection and associated with adaptation to the local environmental conditions in the Baltic- and the North Sea, indicating divergence hitchhiking and the presence of genomic islands of divergence. We report a suite of outlier single nucleotide polymorphisms within or closely located to genes associated with osmoregulation, as well as genes known to play important roles in the hydration and development of oocytes. These genes are likely to have key functions within a general osmoregulatory framework and are important for the survival of eggs and larvae, contributing to the buildup of reproductive isolation between the low-salinity adapted Baltic cod and the adjacent cod populations. Hence, our data suggest that adaptive responses to the environmental conditions in the Baltic Sea may contribute to a strong and effective reproductive barrier, and that Baltic cod can be viewed as an example of ongoing speciation. PMID:25994933
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NASA Astrophysics Data System (ADS)
Guadalupe Vázquez, M.; Bas, Claudia C.; Kittlein, Marcelo; Spivak, Eduardo D.
2015-05-01
The invasive shrimp Palaemon macrodactylus is associated mainly with brackish waters. Previous studies raised the question if tolerance to low salinities differs between larvae and adults. To answer this question, the combined effects of two temperatures (20 and 25 °C) and four salinities (5, 12, 23 and 34 psu) on survival and development of larvae that hatched at the beginning, in the midpoint and near the end of a reproductive season (denoted early, middle season and late larvae respectively) were examined. The three types of larvae were able to survive and reach juvenile phase at salinities between 12 and 34 psu and at both temperatures. At 5 psu all larvae died, but 45% molted at least once. Temperature and salinity to a lesser extent, had effects on the duration of development and on the number of larval stages in all larval types. Development was longer at the lower temperature, especially in middle season and late larvae. Most early larvae reached the juvenile phase through 5 larval stages; the number of larval stages of middle season and late larvae was higher at 20 °C and in late larvae also low salinity produced extra stages. Low salinity (12 psu) and, in early and middle season larvae, low temperature produced lighter and smaller individuals. Response of larvae to environmental factors seems to be related in part to the previous conditions (maternal effects and/or embryo development conditions). The narrower salinity tolerance of larvae compared to adults and the ability of zoea I to survive at least some days at 5 psu may be related with an export larval strategy.
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Park, Jin Hee; Li, Xiaofang; Edraki, Mansour; Baumgartl, Thomas; Kirsch, Bernie
2013-06-01
Coal mining wastes in the form of spoils, rejects and tailings deposited on a mine lease can cause various environmental issues including contamination by toxic metals, acid mine drainage and salinity. Dissolution of salt from saline mine spoil, in particular, during rainfall events may result in local or regional dispersion of salts through leaching or in the accumulation of dissolved salts in soil pore water and inhibition of plant growth. The salinity in coal mine environments is from the geogenic salt accumulations and weathering of spoils upon surface exposure. The salts are mainly sulfates and chlorides of calcium, magnesium and sodium. The objective of the research is to investigate and assess the source and mobility of salts and trace elements in various spoil types, thereby predicting the leaching behavior of the salts and trace elements from spoils which have similar geochemical properties. X-ray diffraction analysis, total digestion, sequential extraction and column experiments were conducted to achieve the objectives. Sodium and chloride concentrations best represented salinity of the spoils, which might originate from halite. Electrical conductivity, sodium and chloride concentrations in the leachate decreased sharply with increasing leaching cycles. Leaching of trace elements was not significant in the studied area. Geochemical classification of spoil/waste defined for rehabilitation purposes was useful to predict potential salinity, which corresponded with the classification from cluster analysis based on leaching data of major elements. Certain spoil groups showed high potential salinity by releasing high sodium and chloride concentrations. Therefore, the leaching characteristics of sites having saline susceptible spoils require monitoring, and suitable remediation technologies have to be applied.
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Transport of persistent organic pollutants by microplastics in estuarine conditions
NASA Astrophysics Data System (ADS)
Bakir, Adil; Rowland, Steven J.; Thompson, Richard C.
2014-03-01
Microplastics represent an increasing source of anthropogenic contamination in aquatic environments, where they may also act as scavengers and transporters of persistent organic pollutants. As estuaries are amongst the most productive aquatic systems, it is important to understand sorption behaviour and transport of persistent organic pollutants (POPs) by microplastics along estuarine gradients. The effects of salinity sorption equilibrium kinetics on the distribution coefficients (Kd) of phenanthrene (Phe) and 4,4‧-DDT, onto polyvinyl chloride (PVC) and onto polyethylene (PE) were therefore investigated. A salinity gradient representing freshwater, estuarine and marine conditions, with salinities corresponding to 0 (MilliQ water, 690 μS/cm), 8.8, 17.5, 26.3 and 35 was used. Salinity had no significant effect on the time required to reach equilibrium onto PVC or PE and neither did it affect desorption rates of contaminants from plastics. Although salinity had no effect on sorption capacity of Phe onto plastics, a slight decrease in sorption capacity was observed for DDT with salinity. Salinity had little effect on sorption behaviour and POP/plastic combination was shown to be a more important factor. Transport of Phe and DDT from riverine to brackish and marine waters by plastic is therefore likely to be much more dependent on the aqueous POP concentration than on salinity. The physical characteristics of the polymer and local environmental conditions (e.g. plastic density, particle residence time in estuaries) will affect the physical transport of contaminated plastics. A transport model of POPs by microplastics under estuarine conditions is proposed. Transport of Phe and DDT by PVC and PE from fresh and brackish water toward fully marine conditions was the most likely net direction for contaminant transport and followed the order: Phe-PE >> DDT-PVC = DDT-PE >> Phe-PVC.
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A Critical Urban Environmental Pedagogy: Relevant Urban Environmental Education for and by Youth
ERIC Educational Resources Information Center
Bellino, Marissa E.; Adams, Jennifer D.
2017-01-01
This article reimagines environmental education (EE), moving away from traditional models of EE rooted in nature studies and pro-environmental behaviors. Using the pedagogical praxis and intent of critical pedagogy and participatory methodologies, this critical urban environmental pedagogy (CUEP) investigates relevant socioenvironmental issues…
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Cao, Jing; Lv, Xiu Yun; Chen, Ling; Xing, Jia Jia; Lan, Hai Yan
2015-01-01
Seed heteromorphism provides plants with alternative strategies for survival in unfavourable environments. However, the response of descendants from heteromorphic seeds to stress has not been well documented. Suaeda aralocaspica is a typical annual halophyte, which produces heteromorphic seeds with disparate forms and different germination characteristics. To gain an understanding of the salt tolerance of descendants and the impact of seed heteromorphism on progeny of this species, we performed a series of experiments to investigate the plant growth and physiological parameters (e.g. osmolytes, oxidative/antioxidative agents and enzymes), as well as expression patterns of corresponding genes. Results showed that osmolytes (proline and glycinebetaine) were significantly increased and that excess reactive oxygen species (O2−, H2O2) produced under high salinity were scavenged by increased levels of antioxidant enzymes (superoxide dismutase, ascorbate peroxidase and glutathione reductase) and corresponding antioxidants (ascorbic acid and glutathione). Moreover, enhancement of phosphoenolpyruvate carboxylase activity at high salt intensity had a positive effect on photosynthesis. The descendants from heteromorphic seeds presented no significant difference in performance with or without salinity. In conclusion, we found that high salinity induced the same active physiological responses in plants from heteromorphic seeds of S. aralocaspica, there was no carry-over of seed heteromorphism to plants: all the descendants required salinity for optimal growth and adaptation to their natural habitat. PMID:26386128
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CroFab reconstitution in various media: an in vitro solubility study.
Vohra, Rais; Clark, Rick; Kelner, Michael
2008-11-01
We investigated the solubility of Crotalidae Polyvalent Ovine Immune Fab antivenom (CroFab, Savage Labs and Protherics Inc., Brentwood, TN, USA) in solutions not listed in the Food and Drug Administration (FDA)-approved product package insert. We also assessed whether adsorption to plastic tubing occurs with CroFab preparations. Nine vials of expired CroFab were divided into three groups according to the solution used for reconstitution. Assignment to the solution groups of normal saline, lactated Ringer's solution, or half-normal saline (NS, LR, 1/2NS) was blinded. The antivenom was diluted to a final volume of 75 mL of test solution. Protein concentration was measured after reconstitution, after storage at 4-6 degrees C for 4 h, and after passage through plastic intravenous (IV) tubing. Higher measured protein yields were noted when half-normal saline was used in comparison with normal saline at each step of the study. Lactated Ringer's solution yielded higher protein concentrations than normal saline only at one out of the three measurement steps. There was no adsorption effect when CroFab was infused through plastic IV tubing. These data suggest that CroFab is slightly more soluble in the hypotonic solution we tested, and the amounts of measured antivenom did not diminish after 4 h of refrigeration or passage through plastic tubing. Our study may be of relevance when clinicians or pharmacists mix CroFab into non-standard solutions.
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NASA Astrophysics Data System (ADS)
Zhang, Zhilin; Savenije, Hubert H. G.
2017-07-01
The practical value of the surprisingly simple Van der Burgh equation in predicting saline water intrusion in alluvial estuaries is well documented, but the physical foundation of the equation is still weak. In this paper we provide a connection between the empirical equation and the theoretical literature, leading to a theoretical range of Van der Burgh's coefficient of 1/2 < K < 2/3 for density-driven mixing which falls within the feasible range of 0 < K < 1. In addition, we developed a one-dimensional predictive equation for the dispersion of salinity as a function of local hydraulic parameters that can vary along the estuary axis, including mixing due to tide-driven residual circulation. This type of mixing is relevant in the wider part of alluvial estuaries where preferential ebb and flood channels appear. Subsequently, this dispersion equation is combined with the salt balance equation to obtain a new predictive analytical equation for the longitudinal salinity distribution. Finally, the new equation was tested and applied to a large database of observations in alluvial estuaries, whereby the calibrated K values appeared to correspond well to the theoretical range.
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Distribution and Diversity of Rhodopsin-Producing Microbes in the Chesapeake Bay.
Maresca, Julia A; Miller, Kelsey J; Keffer, Jessica L; Sabanayagam, Chandran R; Campbell, Barbara J
2018-07-01
Although sunlight is an abundant source of energy in surface environments, less than 0.5% of the available photons are captured by (bacterio)chlorophyll-dependent photosynthesis in plants and bacteria. Metagenomic data indicate that 30 to 60% of the bacterial genomes in some environments encode rhodopsins, retinal-based photosystems found in heterotrophs, suggesting that sunlight may provide energy for more life than previously suspected. However, quantitative data on the number of cells that produce rhodopsins in environmental systems are limited. Here, we use total internal reflection fluorescence microscopy to show that the number of free-living microbes that produce rhodopsins increases along the salinity gradient in the Chesapeake Bay. We correlate this functional data with environmental data to show that rhodopsin abundance is positively correlated with salinity and with indicators of active heterotrophy during the day. Metagenomic and metatranscriptomic data suggest that the microbial rhodopsins in the low-salinity samples are primarily found in Actinobacteria and Bacteroidetes , while those in the high-salinity samples are associated with SAR-11 type Alphaproteobacteria IMPORTANCE Microbial rhodopsins are common light-activated ion pumps in heterotrophs, and previous work has proposed that heterotrophic microbes use them to conserve energy when organic carbon is limiting. If this hypothesis is correct, rhodopsin-producing cells should be most abundant where nutrients are most limited. Our results indicate that in the Chesapeake Bay, rhodopsin gene abundance is correlated with salinity, and functional rhodopsin production is correlated with nitrate, bacterial production, and chlorophyll a We propose that in this environment, where carbon and nitrogen are likely not limiting, heterotrophs do not need to use rhodopsins to supplement ATP synthesis. Rather, the light-generated proton motive force in nutrient-rich environments could be used to power energy-dependent membrane-associated processes, such as active transport of organic carbon and cofactors, enabling these organisms to more efficiently utilize exudates from primary producers. Copyright © 2018 American Society for Microbiology.
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NASA Astrophysics Data System (ADS)
Malard, J. J.; Baig, A. I.; Hassanzadeh, E.; Adamowski, J. F.; Tuy, H.; Melgar-Quiñonez, H.
2016-12-01
Model coupling is a crucial step to constructing many environmental models, as it allows for the integration of independently-built models representing different system sub-components to simulate the entire system. Model coupling has been of particular interest in combining socioeconomic System Dynamics (SD) models, whose visual interface facilitates their direct use by stakeholders, with more complex physically-based models of the environmental system. However, model coupling processes are often cumbersome and inflexible and require extensive programming knowledge, limiting their potential for continued use by stakeholders in policy design and analysis after the end of the project. Here, we present Tinamit, a flexible Python-based model-coupling software tool whose easy-to-use API and graphical user interface make the coupling of stakeholder-built SD models with physically-based models rapid, flexible and simple for users with limited to no coding knowledge. The flexibility of the system allows end users to modify the SD model as well as the linking variables between the two models themselves with no need for recoding. We use Tinamit to couple a stakeholder-built socioeconomic model of soil salinization in Pakistan with the physically-based soil salinity model SAHYSMOD. As climate extremes increase in the region, policies to slow or reverse soil salinity buildup are increasing in urgency and must take both socioeconomic and biophysical spheres into account. We use the Tinamit-coupled model to test the impact of integrated policy options (economic and regulatory incentives to farmers) on soil salinity in the region in the face of future climate change scenarios. Use of the Tinamit model allowed for rapid and flexible coupling of the two models, allowing the end user to continue making model structure and policy changes. In addition, the clear interface (in contrast to most model coupling code) makes the final coupled model easily accessible to stakeholders with limited technical background.
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Exploring the diversity-stability paradigm using sponge microbial communities.
Glasl, Bettina; Smith, Caitlin E; Bourne, David G; Webster, Nicole S
2018-05-30
A key concept in theoretical ecology is the positive correlation between biodiversity and ecosystem stability. When applying this diversity-stability concept to host-associated microbiomes, the following questions emerge: (1) Does microbial diversity influence the stability of microbiomes upon environmental fluctuations? (2) Do hosts that harbor high versus low microbial diversity differ in their stress response? To test the diversity-stability concept in host-associated microbiomes, we exposed six marine sponge species with varying levels of microbial diversity to non-lethal salinity disturbances and followed their microbial composition over time using 16S rRNA gene amplicon sequencing. No signs of sponge stress were evident following salinity amendment and microbiomes exhibited compositional resistance irrespective of their microbial diversity. Compositional stability of the sponge microbiome manifests itself at distinct host taxonomic and host microbial diversity groups, with (1) stable host genotype-specific microbiomes at oligotype-level; (2) stable host species-specific microbiomes at genus-level; and (3) stable and specific microbiomes at phylum-level for hosts with high versus low microbial diversity. The resistance of sponge microbiomes together with the overall stability of sponge holobionts upon salinity fluctuations suggest that the stability-diversity concept does not appear to hold for sponge microbiomes and provides further evidence for the widely recognized environmental tolerance of sponges.
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Esteves, Kévin; Mosser, Thomas; Aujoulat, Fabien; Hervio-Heath, Dominique; Monfort, Patrick; Jumas-Bilak, Estelle
2015-01-01
Vibrio parahaemolyticus and Vibrio cholerae are ubiquitous to estuarine and marine environments. These two species found in Mediterranean coastal systems can induce infections in humans. Environmental isolates of V. cholerae (n = 109) and V. parahaemolyticus (n = 89) sampled at different dates, stations and water salinities were investigated for virulence genes and by a multilocus sequence-based analysis (MLSA). V. cholerae isolates were all ctxA negative and only one isolate of V. parahaemolyticus displayed trh2 gene. Most Sequence Types (ST) corresponded to unique ST isolated at one date or one station. Frequent recombination events were detected among different pathogenic species, V. parahaemolyticus, V. cholerae, Vibrio mimicus, and Vibrio metoecus. Recombination had a major impact on the diversification of lineages. The genetic diversity assessed by the number of ST/strain was higher in low salinity condition for V. parahaemolyticus and V. cholerae whereas the frequency of recombination events in V. cholerae was lower in low salinity condition. Mediterranean coastal lagoon systems housed V. cholerae and V. parahaemolyticus with genetic diversities equivalent to the worldwide diversity described so far. The presence of STs found in human infections as well as the frequency of recombination events in environmental vibrios populations could predict a potential epidemiological risk. PMID:26236294
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[Research on mercury methylation by Geobacter sulfurreducens and its influencing factors].
Zou, Yan; Si, You-Bin; Yan, Xue; Chen, Yan
2012-09-01
Mercury methylation by Geobacter sulfurreducens and the effects of environmental factors were studied under laboratory conditions. The results showed that G. sulfurreducens could grow well in the presence of low concentrations of mercuric chloride, but its growth was inhibited to a certain extent, mainly expressed in the prolonged lag phase. G. sulfurreducens could transform inorganic mercury into methylmercury, and this process was affected by many environmental factors. The efficiency of mercury methylation reached 38% under anaerobic conditions with 1 mg x L(-1) HgCl2 and 0.9% salinity at 35 degrees C, pH 6.0. Increasing the initial HgCl2 concentration or salinity in an appropriate manner improved mercury methylation, but the concentration of methylmercury reduced when the concentrations of HgCl2 and salinity were too high. The efficiency of mercury methylation increased with the increasing temperature in range of 4-35 degrees C. Weakly acidic environment was more beneficial to mercury methylation than acidic, neutral or alkaline conditions. In addition, the efficiency of mercury methylation was also affected by humic acid and cysteine. Humic acid inhibited mercury methyaltion, whereas cysteine could improve the efficiency of mercury methylation. This study provided a direct evidence for mercury methylation mediated by iron-reducing bacteria in the natural aquatic ecosystem.
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Variation in benthic long-term data of transitional waters: Is interpretation more than speculation?
Zettler, Michael Lothar; Friedland, René; Gogina, Mayya; Darr, Alexander
2017-01-01
Biological long-term data series in marine habitats are often used to identify anthropogenic impacts on the environment or climate induced regime shifts. However, particularly in transitional waters, environmental properties like water mass dynamics, salinity variability and the occurrence of oxygen minima not necessarily caused by either human activities or climate change can attenuate or mask apparent signals. At first glance it very often seems impossible to interpret the strong fluctuations of e.g. abundances or species richness, since abiotic variables like salinity and oxygen content vary simultaneously as well as in apparently erratic ways. The long-term development of major macrozoobenthic parameters (abundance, biomass, species numbers) and derivative macrozoobenthic indices (Shannon diversity, Margalef, Pilou’s evenness and Hurlbert) has been successfully interpreted and related to the long-term fluctuations of salinity and oxygen, incorporation of the North Atlantic Oscillation index (NAO index), relying on the statistical analysis of modelled and measured data during 35 years of observation at three stations in the south-western Baltic Sea. Our results suggest that even at a restricted spatial scale the benthic system does not appear to be tightly controlled by any single environmental driver and highlight the complexity of spatially varying temporal response. PMID:28422974
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Lee, Jessica A; Francis, Christopher A
2017-12-01
Denitrification is a dominant nitrogen loss process in the sediments of San Francisco Bay. In this study, we sought to understand the ecology of denitrifying bacteria by using next-generation sequencing (NGS) to survey the diversity of a denitrification functional gene, nirS (encoding cytchrome-cd 1 nitrite reductase), along the salinity gradient of San Francisco Bay over the course of a year. We compared our dataset to a library of nirS sequences obtained previously from the same samples by standard PCR cloning and Sanger sequencing, and showed that both methods similarly demonstrated geography, salinity and, to a lesser extent, nitrogen, to be strong determinants of community composition. Furthermore, the depth afforded by NGS enabled novel techniques for measuring the association between environment and community composition. We used Random Forests modelling to demonstrate that the site and salinity of a sample could be predicted from its nirS sequences, and to identify indicator taxa associated with those environmental characteristics. This work contributes significantly to our understanding of the distribution and dynamics of denitrifying communities in San Francisco Bay, and provides valuable tools for the further study of this key N-cycling guild in all estuarine systems. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.
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Polymer tensiometers in a saline environment.
NASA Astrophysics Data System (ADS)
van der Ploeg, Martine; Gooren, H. P. A.; Bakker, G.; Russell, W.; Hoogendam, C. W.; Huiskes, C.; Shouse, P.; de Rooij, G. H.
2010-05-01
It is estimated that 20% of all cultivated land and nearly half of the irrigated land is salt-affected, which pose major economic and environmental problems. Salinity may be the result of two processes; dryland and irrigation salinity. Dryland salinity is caused by a rise in the groundwater table, which occurs as a result of the replacement of deep-rooted, perennial native vegetation by shallow-rooted annual species meant for production. Irrigation salinity may occur as a result of poor water quality, poor drainage, or inefficient use of water. Consequently, new strategies to enhance crop yield stability on saline soils represent a major research priority (Botella et al. 2005). At the same time, native vegetation is capable of thriving under saline and/or dry conditions. The plant physiology of such vegetation has been investigated thoroughly, but the relation with in situ soil properties (soil moisture and salinity) may be more difficult to unravel as soil moisture sensors are less sensitive in dry soil, and the signal of most soil moisture content sensors is strongly attenuated by soil salinity. Recently, polymer tensiometer were developed that are able to measure matric potentials (closely related to a soil's moisture status) in dry soils. Polymer tensiometers consist of a solid ceramic, a stainless steel cup and a pressure transducer. The ceramic consist of a support layer and a membrane with 2 nm pore-size to prevent polymer leakage. Between the ceramic membrane and the pressure transducer a tiny chamber is located, which contains the polymer solution. The polymer's osmotic potential strongly reduces the total water potential inside the polymer tensiometer, which causes build-up of osmotic pressure. Polymer tensiometers would thus be an ideal instrument to measure in dry soil, if the polymer inside the tensiometer is not affected by the salts in the soil solution. We will address some key issues regarding the use of POTs in saline environments by showing results from a field experiment conducted in a very saline soil. This research was funded by the Dutch Technology Foundation (STW).
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Bigheaded carps : a biological synopsis and environmental risk assessment
Kolar, Cindy S.; Chapman, Duane C.; Courtenay, Walter R.; Housel, Christine M.; Williams, James D.; Jennings, Dawn P.
2007-01-01
Includes information on taxonomy and distinguishing characteristics, hybrids, native and introduced ranges, temperature and salinity tolerances, fecundity, sexual maturity and mating behavior, spawning, early development, feeding habits, growth rate and longevity, response to physical stimuli, associated diseases and parasites, human uses, environmental effects, potential range, population control measures. Summarizes United States federal and state regulations, and assesses the risk posed by these species in the United States.
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Field-scale apparent soil electrical conductivity
USDA-ARS?s Scientific Manuscript database
Soils are notoriously spatially heterogeneous and many soil properties (e.g., salinity, water content, trace element concentration, etc.) are temporally variable, making soil a complex media. Spatial variability of soil properties has a profound influence on agricultural and environmental processes ...
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MEASURING THE ACUTE TOXICITY OF ESTUARINE SEDIMENTS
Estuarine sediments frequently are repositories and sources of anthropogenic contaminants. Toxicity is one method of assessing the environmental quality of sediments, yet because of the extreme range of salinities that characterize estuaries few infaunal organisms have both the p...
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ERIC Educational Resources Information Center
Plake, Linda Perry
1977-01-01
A comprehensive discussion of the biological activity in tidal pools is provided. The importance of environmental factors such as oxygen supply, temperature, salinity, and light is detailed. Plants and animals that might be found in a tidal pool are identified and described. (BT)
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Schwarting Miller, Lindsay; La Peyre, Jerome F.; LaPeyre, Megan K.
2017-01-01
Recognition of the global loss of subtidal oyster reefs has led to a rise in reef restoration efforts, including in the Gulf of Mexico. Created reef success depends entirely on selecting a location that supports long-term oyster growth and survival, including the recruitment and survival of on-reef oysters. Significant changes in estuarine salinity through management of freshwater inflows and through changed precipitation patterns may significantly impact the locations of optimal oyster restoration sites. These rapid shifts in conditions necessitate a need to better understand both impacts to on-reef oyster growth and population development, and variation in oyster stock performance. Oyster growth, mortality, condition, and disease prevalence were examined in three different stocks of oysters located in protected cages, as well as oyster recruitment and mortality on experimental reef units in three different locations representing a salinity gradient, along the Louisiana Gulf coast in 2011 and 2012. Over a 2-y period, the high-salinity site had highest oyster growth rate in protected cages but demonstrated the least likelihood for reef development based on on-reef oyster population failure, likely because of predation-related mortality (high recruitment and 100% mortality). In contrast, the midsalinity site with moderate oyster growth and on-reef recruitment and low mortality demonstrated a higher likelihood for reef development. The lowest salinity site exhibited extreme variability in all oyster responses between years because of extreme variation in environmental conditions during the study, indicating a low likelihood of long-term reef development. Whereas limited differences in stock performance between sites were found, the range of site environmental conditions tested was ultimately much lower than expected and may not have provided a wide enough range of conditions. In areas with limited, low recruitment, or rapidly changing environmental conditions, seeding with stocks selected for best growth and survival under expected future environmental conditions could better ensure reef development by using oyster populations best suited to the predicted conditions. With rapidly changing estuarine conditions from anthropogenic activities and climate change, siting of oyster reef restoration incorporating both oyster population dynamics and in situ biotic and abiotic interactions is critical in better directing site selection for reef restoration efforts.
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Jelavić, S; Stipp, S L S; Bovet, N
2018-06-27
An understanding of the mechanisms that control the adsorption of organic molecules on clay minerals is of interest in several branches of science and industry. Oil production using low salinity injection fluids can increase yields by as much as 40% over standard injection with seawater or formation water. The mechanism responsible for the low salinity response is still debated, but one hypothesis is a change in pore surface wettability. Organic contamination in soil and drinking water aquifers is a challenge for municipal water suppliers and for agriculture. A better understanding is needed for how mineral species, solution composition and pH affect the desorption of low molecular weight organic ligands from clay minerals and consequently their wettability. We used X-ray photoelectron spectroscopy under cryogenic conditions to investigate the in situ composition in the mineral-solution interface region in a series of experiments with a range of pH and ion concentrations. We demonstrate that both chlorite and kaolinite release organic molecules under conditions relevant for low salinity water flooding. This release increases with a higher solution pH but is only slightly affected by the character of the organic ligand. This is consistent with the observation that low salinity enhanced oil recovery correlates with the presence of chlorite and kaolinite. Our results indicate that the pore surface charge and salinity of formation water and injection fluids are key parameters in determining the low salinity response. In general, our results imply that clay mineral surface charge influences the composition in the interface through an affinity for organic molecules.
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NASA Astrophysics Data System (ADS)
Inam, Azhar; Adamowski, Jan; Prasher, Shiv; Halbe, Johannes; Malard, Julien; Albano, Raffaele
2017-08-01
Many simulation models focus on simulating a single physical process and do not constitute balanced representations of the physical, social and economic components of a system. The present study addresses this challenge by integrating a physical (P) model (SAHYSMOD) with a group (stakeholder) built system dynamics model (GBSDM) through a component modeling approach based on widely applied tools such as MS Excel, Python and Visual Basic for Applications (VBA). The coupled model (P-GBSDM) was applied to test soil salinity management scenarios (proposed by stakeholders) for the Haveli region of the Rechna Doab Basin in Pakistan. Scenarios such as water banking, vertical drainage, canal lining, and irrigation water reallocation were simulated with the integrated model. Spatiotemporal maps and economic and environmental trade-off criteria were used to examine the effectiveness of the selected management scenarios. After 20 years of simulation, canal lining reduced soil salinity by 22% but caused an initial reduction of 18% in farm income, which requires an initial investment from the government. The government-sponsored Salinity Control and Reclamation Project (SCARP) is a short-term policy that resulted in a 37% increase in water availability with a 12% increase in farmer income. However, it showed detrimental effects on soil salinity in the long term, with a 21% increase in soil salinity due to secondary salinization. The new P-GBSDM was shown to be an effective platform for engaging stakeholders and simulating their proposed management policies while taking into account socioeconomic considerations. This was not possible using the physically based SAHYSMOD model alone.
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Salinization and Saline Environments
NASA Astrophysics Data System (ADS)
Vengosh, A.
2003-12-01
One of the most conspicuous phenomena of water-quality degradation, particularly in arid and semi-arid zones, is salinization of water and soil resources. Salinization is a long-term phenomenon, and during the last century many aquifers and river basins have become unsuitable for human consumption owing to high levels of salinity. Future exploitation of thousands of wells in the Middle East and in many other water-scarce regions in the world depends, to a large extent, on the degree and rate of salinization. Moreover, every year a large fraction of agricultural land is salinized and becomes unusable.Salinization is a global environmental phenomenon that affects many different aspects of our life (Williams, 2001a, b): changing the chemical composition of natural water resources (lakes, rivers, and groundwater), degrading the quality of water supply to the domestic and agriculture sectors, contribution to loss of biodiversity, taxonomic replacement by halotolerant species ( Williams, 2001a, b), loss of fertile soil, collapse of agricultural and fishery industries, changing of local climatic conditions, and creating severe health problems (e.g., the Aral Basin). The damage due to salinity in the Colorado River Basin alone, for example, ranges between 500 and 750 million per year and could exceed 1 billion per year if the salinity in the Imperial Dam increases from 700 mg L-1 to 900 mg L-1 (Bureau of Reclamation, 2003, USA). In Australia, accelerating soil salinization has become a massive environmental and economic disaster. Western Australia is "losing an area equal to one football oval an hour" due to spreading salinity ( Murphy, 1999). The annual cost for dryland salinity in Australia is estimated as AU700 million for lost land and AU$130 million for lost production ( Williams et al., 2002). In short, the salinization process has become pervasive.Salinity in water is usually defined by the chloride content (mg L-1) or total dissolved solids content (TDS, mg L-1or g L-1), although the chloride comprises only a fraction of the total dissolved salts in water. The Cl/TDS ratio varies from 0.1 in nonmarine saline waters to ˜0.5 in marine-associated saline waters. Water salinity is also defined by electrical conductivity (EC). In soil studies, the electrical conductivity and the ratio of Na/√(Ca+Mg) (SAR) are often used as an indirect measure of soil salinity. In addition to chloride, high levels of other dissolved constituents may limit the use of water for domestic, agriculture, and industrial applications. In some parts of Africa, China, and India, for example, high fluoride content is associated with saline groundwater and causes severe dental and skeletal fluorosis (Shiklomanov, 1997). Hence, the "salinity" problem is only the "tip of the iceberg," as high levels of salinity are associated with high concentrations of other inorganic pollutants (e.g., sodium, sulfate, boron, fluoride), and bioaccumulated elements (e.g., selenium, and arsenic) (see Chapter 9.03).The World Health Organization (WHO) recommends that the chloride concentration of the water supply for human consumption should not exceed 250 mg L-1. Agriculture applications also depend upon the salinity level of the supplied water. Many crops, such as citrus, avocado, and mango, are sensitive to chloride concentration in irrigation water (an upper limit of 250 mg L-1). In addition, long-term irrigation with water enriched with sodium results in a significant reduction in the hydraulic conductivity and hence the fertility of the irrigated soil. Similarly, the industrial sector demands water of high quality. For example, the high-tech industry requires a large amount of water with low levels of dissolved salts. Hence, the salinity level of groundwater is one of the limiting factors that determine the suitability of water for a variety of applications.The salinity problem is a global phenomenon but it is more severe in water-scarce areas, such as arid and semi-arid zones. The increasing demand for water has created tremendous pressures on water resources that have resulted in lowering water level and increasing salinization. For example, in the Middle East salinity is the main factor that limits water utilization, and future prospects for water use in Israel, Palestinian Authority, and Jordan are overshadowed by the increasing salinization (Vengosh and Rosenthal, 1994; Salameh, 1996). The salinity problem has numerous grave economic, social, and political consequences, particularly in cross-boundary basins that are shared by different communities (e.g., Salinas Valley California; Vengosh et al., 2002a), friendly states (e.g., salinization of the Colorado River along Mexico-US border; Stanton et al., 2001), and hostile states (e.g., the Jordan River, Vengosh et al., 2001; Aral Basin, Weinthal, 2002; Euphrates River, Beaumont, 1996; and the Nile River, Ohlsson, 1995).Salinization of water resources also affects agricultural management. The type of irrigation water and its quality determine the salinity and fertility of the soil and eventually the quality of the underlying water resource. The use of treated wastewater or other marginal water (e.g., brackish water) depends on the salinity and the chemical composition of the water. Treated wastewater with high contents of chloride, sodium, and boron is suitable only for salt-tolerant crops and requires special treatment of the soil. Finally, high boron in irrigation water and consequently in soil water is also an important limiting factor for crops, as boron is an essential micronutrient for plants but becomes toxic at high levels (typically >0.75 mg L-1 in irrigation water).This chapter investigates the different mechanisms and geochemistry of salinization in different parts of the world. The role of the unsaturated zone in shaping the chemical composition of dryland salinization is discussed. Special emphasis is on the anthropogenic effects and to man-made fluids and reused water, such as treated wastewater and agricultural drainage water. Two anthropogenic salinization cycles are introduced - the agricultural and the domestic cycles. Some useful geochemical fingerprinting tracers are also included for defining the sources of salinity. Finally, the chemical composition of future water resources is predicted, based on the chemical and isotopic fractionation associated with remediation and desalination.
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Salinity Processes in the Upper Ocean Regional Study (SPURS)
2012-09-04
Two NOAA Pacific Marine Environmental Laboratory (PMEL) buoys are seen on the stern of the Woods Hole Oceanographic Institution's research vessel Knorr on Tuesday, Sept. 4, 2012, in Woods Hole, Mass. Knorr is scheduled to depart on Sept. 6 to take part in the Salinity Processes in the Upper Ocean Regional Study (SPURS). The NASA-sponsored expedition will sail to the North Atlantic's saltiest spot to get a detailed, 3-D picture of how salt content fluctuates in the ocean's upper layers and how these variations are related to shifts in rainfall patterns around the planet. Photo Credit: (NASA/Bill Ingalls)
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Phase 0 study for a geothermal superheated water proof of concept facility
NASA Technical Reports Server (NTRS)
Douglass, R. H.; Pearson, R. O.
1974-01-01
A Phase 0 study for the selection of a representative liquid-dominated geothermal resource of moderate salinity and temperature is discussed. Selection and conceptual design of a nominal 10-MWe energy conversion system, and implementation planning for Phase 1: subsystem (component, experiments) and Phase 2: final design, construction, and operation of experimental research facilities are reported. The objective of the overall program is to demonstrate the technical and economic viability of utilizing moderate temperature and salinity liquid-dominated resources with acceptable environmental impact, and thus encourage commercial scale development of geothermal electrical power generation.
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NASA Astrophysics Data System (ADS)
La Peyre, Megan K.; Eberline, Benjamin S.; Soniat, Thomas M.; La Peyre, Jerome F.
2013-12-01
Understanding how different life history stages are impacted by extreme or stochastic environmental variation is critical for predicting and modeling organism population dynamics. This project examined recruitment, growth, and mortality of seed (25-75 mm) and market (>75 mm) sized oysters along a salinity gradient over two years in Breton Sound, LA. In April 2010, management responses to the Deepwater Horizon oil spill resulted in extreme low salinity (<5) at all sites through August 2010; in 2011, a 100-year Mississippi River flood event resulted in low salinity in late spring. Extended low salinity (<5) during hot summer months (>25 °C) significantly and negatively impacted oyster recruitment, survival and growth in 2010, while low salinity (<5) for a shorter period that did not extend into July (<25 °C) in 2011 had minimal impacts on oyster growth and mortality. In 2011, recruitment was limited, which may be due to a combination of low spring time salinities, high 2010 oyster mortality, minimal 2010 recruitment, cumulative effects from 10 years of declining oyster stock in the area, and poor cultch quality. In both 2010 and 2011, Perkinsus marinus infection prevalence remained low throughout the year at all sites and almost all infection intensities were light. Oyster plasma osmolality failed to match surrounding low salinity waters in 2010, while oysters appeared to osmoconform throughout 2011 indicating that the high mortality in 2010 may be due to extended valve closing and resulting starvation or asphyxiation in response to the combination of low salinity during high temperatures (>25 °C). With increasing management of our freshwater inputs to estuaries combined with predicted climate changes, how extreme events affect different life history stages is key to understanding variation in population demographics of commercially important species and predicting future populations.
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Kruk, Carla; Segura, Angel M; Nogueira, Lucía; Alcántara, Ignacio; Calliari, Danilo; Martínez de la Escalera, Gabriela; Carballo, Carmela; Cabrera, Carolina; Sarthou, Florencia; Scavone, Paola; Piccini, Claudia
2017-12-01
The Microcystis aeruginosa complex (MAC) clusters cosmopolitan and conspicuous harmful bloom-forming cyanobacteria able to produce cyanotoxins. It is hypothesized that low temperatures and brackish salinities are the main barriers to MAC proliferation. Here, patterns at multiple levels of organization irrespective of taxonomic identity (i.e. a trait-based approach) were analyzed. MAC responses from the intracellular (e.g. respiratory activity) to the ecosystem level (e.g. blooms) were evaluated in wide environmental gradients. Experimental results on buoyancy and respiratory activity in response to increased salinity (0-35) and a literature review of maximum growth rates under different temperatures and salinities were combined with field sampling from headwaters (800km upstream) to the marine end of the Rio de la Plata estuary (Uruguay-South America). Salinity and temperature were the major variables affecting MAC responses. Experimentally, freshwater MAC cells remained active for 24h in brackish waters (salinity=15) while colonies increased their flotation velocity. At the population level, maximum growth rate decreased with salinity and presented a unimodal exponential response with temperature, showing an optimum at 27.5°C and a rapid decrease thereafter. At the community and ecosystem levels, MAC occurred from fresh to marine waters (salinity 30) with a sustained relative increase of large mucilaginous colonies biovolume with respect to individual cells. Similarly, total biomass and, specific and morphological richness decreased with salinity while blooms were only detected in freshwater both at high (33°C) and low (11°C) temperatures. In brackish waters, large mucilaginous colonies presented advantages under osmotic restrictive conditions. These traits values have also been associated with higher toxicity potential. This suggest salinity or low temperatures would not represent effective barriers for the survival and transport of potentially toxic MAC under likely near future scenarios of increasing human impacts (i.e. eutrophication, dam construction and climate change). Copyright © 2017 Elsevier B.V. All rights reserved.
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Ozaslan, Cumali; Farooq, Shahid; Onen, Huseyin; Bukun, Bekir; Ozcan, Selcuk; Gunal, Hikmet
2016-01-01
Invasive plants are recognized for their impressive abilities to withstand adverse environmental conditions however, all invaders do not express the similar abilities. Therefore, survival, growth, nutrient uptake and fecundity of two co-occurring, invasive Physalis species were tested under water and salinity stresses, and different soil textures in the current study. Five different water stress levels (100, 75, 50, 25, and 12.5% pot water contents), four different soil salinity levels (0, 3, 6, and 12 dSm-1) and four different soil textures (67% clay, 50% clay, silt clay loam and sandy loam) were included in three different pot experiments. Both weeds survived under all levels of water stress except 12.5% water contents and on all soil types however, behaved differently under increasing salinity. The weeds responded similarly to salinity up till 3 dSm-1 whereas, P. philadelphica survived for longer time than P. angulata under remaining salinity regimes. Water and salinity stress hampered the growth and fecundity of both weeds while, soil textures had slight effect. Both weeds preferred clay textured soils for better growth and nutrient uptake however, interactive effect of weeds and soil textures was non-significant. P. angulata accumulated higher K and Na while P. philadelphica accrued more Ca and Mg as well as maintained better K/Na ratio. P. angulata accumulated more Na and P under salinity stress while, P. philadelphica accrued higher K and Mg, and maintained higher K/Na ratio. Collectively, highest nutrient accumulation was observed under stress free conditions and on clay textured soils. P. philadelphica exhibited higher reproductive output under all experimental conditions than P. angulata. It is predicted that P. philadelphica will be more problematic under optimal water supply and high salinity while P. angulata can better adapt water limited environments. The results indicate that both weeds have considerable potential to further expand their ranges in semi-arid regions of Turkey.
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Ozaslan, Cumali; Bukun, Bekir; Ozcan, Selcuk
2016-01-01
Invasive plants are recognized for their impressive abilities to withstand adverse environmental conditions however, all invaders do not express the similar abilities. Therefore, survival, growth, nutrient uptake and fecundity of two co-occurring, invasive Physalis species were tested under water and salinity stresses, and different soil textures in the current study. Five different water stress levels (100, 75, 50, 25, and 12.5% pot water contents), four different soil salinity levels (0, 3, 6, and 12 dSm-1) and four different soil textures (67% clay, 50% clay, silt clay loam and sandy loam) were included in three different pot experiments. Both weeds survived under all levels of water stress except 12.5% water contents and on all soil types however, behaved differently under increasing salinity. The weeds responded similarly to salinity up till 3 dSm-1 whereas, P. philadelphica survived for longer time than P. angulata under remaining salinity regimes. Water and salinity stress hampered the growth and fecundity of both weeds while, soil textures had slight effect. Both weeds preferred clay textured soils for better growth and nutrient uptake however, interactive effect of weeds and soil textures was non-significant. P. angulata accumulated higher K and Na while P. philadelphica accrued more Ca and Mg as well as maintained better K/Na ratio. P. angulata accumulated more Na and P under salinity stress while, P. philadelphica accrued higher K and Mg, and maintained higher K/Na ratio. Collectively, highest nutrient accumulation was observed under stress free conditions and on clay textured soils. P. philadelphica exhibited higher reproductive output under all experimental conditions than P. angulata. It is predicted that P. philadelphica will be more problematic under optimal water supply and high salinity while P. angulata can better adapt water limited environments. The results indicate that both weeds have considerable potential to further expand their ranges in semi-arid regions of Turkey. PMID:27741269
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Stagg, Camille L.; Baustian, Melissa M.; Perry, Carey L.; Carruthers, Tim J.B.; Hall, Courtney T.
2018-01-01
Coastal wetlands store more carbon than most ecosystems globally. As sea level rises, changes in flooding and salinity will potentially impact ecological functions, such as organic matter decomposition, that influence carbon storage. However, little is known about the mechanisms that control organic matter loss in coastal wetlands at the landscape scale. As sea level rises, how will the shift from fresh to salt-tolerant plant communities impact organic matter decomposition? Do long-term, plant-mediated, effects of sea-level rise differ from direct effects of elevated salinity and flooding?We identified internal and external factors that regulated indirect and direct pathways of sea-level rise impacts, respectively, along a landscape-scale salinity gradient that incorporated changes in wetland type (fresh, oligohaline, mesohaline and polyhaline marshes). We found that indirect and direct impacts of sea-level rise had opposing effects on organic matter decomposition.Salinity had an indirect effect on litter decomposition that was mediated through litter quality. Despite significant variation in environmental conditions along the landscape gradient, the best predictors of above- and below-ground litter decomposition were internal drivers, initial litter nitrogen content and initial litter lignin content respectively. Litter decay constants were greatest in the oligohaline marsh and declined with increasing salinity, and the fraction of litter remaining (asymptote) was greatest in the mesohaline marsh. In contrast, direct effects of salinity and flooding were positive. External drivers, salinity and flooding, stimulated cellulytic activity, which was highest in the polyhaline marsh.Synthesis. Our results indicate that as sea level rises, initial direct effects of salinity will stimulate decay of labile carbon, but over time as plant communities shift from fresh to polyhaline marsh, litter decay will decline, yielding greater potential for long-term carbon storage. These findings highlight the importance of quantifying carbon loss at multiple temporal scales, not only in coastal wetlands but also in other ecosystems where plant-mediated responses to climate change will have significant impacts on carbon cycling.
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LaPeyre, Megan K.; Eberline, Benjamin S.; Soniat, Thomas M.; La Peyre, Jerome F.
2013-01-01
Understanding how different life history stages are impacted by extreme or stochastic environmental variation is critical for predicting and modeling organism population dynamics. This project examined recruitment, growth, and mortality of seed (25–75 mm) and market (>75 mm) sized oysters along a salinity gradient over two years in Breton Sound, LA. In April 2010, management responses to the Deepwater Horizon oil spill resulted in extreme low salinity (<5) at all sites through August 2010; in 2011, a 100-year Mississippi River flood event resulted in low salinity in late spring. Extended low salinity (<5) during hot summer months (>25 °C) significantly and negatively impacted oyster recruitment, survival and growth in 2010, while low salinity (<5) for a shorter period that did not extend into July (<25 °C) in 2011 had minimal impacts on oyster growth and mortality. In 2011, recruitment was limited, which may be due to a combination of low spring time salinities, high 2010 oyster mortality, minimal 2010 recruitment, cumulative effects from 10 years of declining oyster stock in the area, and poor cultch quality. In both 2010 and 2011, Perkinsus marinusinfection prevalence remained low throughout the year at all sites and almost all infection intensities were light. Oyster plasma osmolality failed to match surrounding low salinity waters in 2010, while oysters appeared to osmoconform throughout 2011 indicating that the high mortality in 2010 may be due to extended valve closing and resulting starvation or asphyxiation in response to the combination of low salinity during high temperatures (>25 °C). With increasing management of our freshwater inputs to estuaries combined with predicted climate changes, how extreme events affect different life history stages is key to understanding variation in population demographics of commercially important species and predicting future populations.
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Shao, Tianyun; Li, Lingling; Wu, Yawen; Chen, Manxia; Long, Xiaohua; Shao, Hongbo; Liu, Zhaopu; Rengel, Zed
2016-10-15
Salinity is one of the most serious environmental stresses limiting agricultural production. Production of Jerusalem artichoke on saline land is strategically important for using saline land resources. The interaction between plant hormones and salinity stress in governing Jerusalem artichoke (Helianthus tuberosus) growth is unclear. Jerusalem artichoke (variety Nanyu-1) was grown under variable salinity stress in the field, and a role of endogenous hormones [zeatin (ZT), auxins (IAA), gibberellins (GA3) and abscisic acid (ABA)] in regulating sugar and dry matter accumulation in tubers was characterized. Under mild salt stress (≤2.2gNaClkg(-1) soil), Nanyu-1 grew well with no significant alteration of dry matter distribution to stems and tubers. In contrast, under moderate salt stress (2.7gNaClkg(-1) soil), the distribution to stem decreased and to tubers decreased significantly. Mild salt stress induced sugar accumulation in tubers at the beginning of the tuber-expansion period, but significantly inhibited (i) transfer of non-reducing sugars to tubers, and (ii) polymerization and accumulation of fructan during the tuber-expansion stage. Under different salinity stress, before the stolon growth, the ratio of IAA/ABA in leaves increased significantly and that of GA3/ABA increased slightly; during tuber development, these ratios continued to decrease and reached the minimum late in the tuber-expansion period. While, salt stress inhibited (i) underground dry matter accumulation, (ii) tuber dry matter accumulation efficiency, (iii) transport of non-reducing sugars to tubers, and (iv) fructan accumulation efficiency during the tuber-expansion period; these effects were accompanied by significantly decreased tuber yield with an increase in salinity. With soil salinity increasing, the synthesis of IAA and GA3 was inhibited in leaves and tubers, while ABA synthesis was stimulated. In brief, tuber yield would significantly decreased with the increase of salinity. Copyright © 2016 Elsevier B.V. All rights reserved.
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Céspedes, V; Pallarés, S; Arribas, P; Millán, A; Velasco, J
2013-10-01
Water salinity and ionic composition are among the main environmental variables that constrain the fundamental niches of aquatic species, and accordingly, physiological tolerance to these factors constitutes a crucial part of the evolution, ecology, and biogeography of these organisms. The present study experimentally estimated the fundamental saline and anionic niches of adults of two pairs of congeneric saline beetle species that differ in habitat preference (lotic and lentic) in order to test the habitat constraint hypothesis. Osmotic and anionic realised niches were also estimated based on the field occurrences of adult beetle species using Outlying Mean Index analysis and their relationship with experimental tolerances. In the laboratory, all of the studied species showed a threshold response to increased salinity, displaying high survival times when exposed to low and intermediate conductivity levels. These results suggest that these species are not strictly halophilic, but that they are able to regulate both hyperosmotically and hypoosmotically. Anionic water composition had a significant effect on salinity tolerance at conductivity levels near their upper tolerance limits, with decreased species survival at elevated sulphate concentrations. Species occupying lentic habitats demonstrated higher salinity tolerance than their lotic congeners in agreement with the habitat constraint hypothesis. As expected, realised salinity niches were narrower than fundamental niches and corresponded to conditions near the upper tolerance limits of the species. These species are uncommon on freshwater-low conductivity habitats despite the fact that these conditions might be physiologically suitable for the adult life stage. Other factors, such as biotic interactions, could prevent their establishment at low salinities. Differences in the realised anionic niches of congeneric species could be partially explained by the varying habitat availability in the study area. Combining the experimental estimation of fundamental niches with realised field data niche estimates is a powerful method for understanding the main factors constraining species' distribution at multiple scales, which is a key issue when predicting species' ability to cope with global change. Copyright © 2013 Elsevier Ltd. All rights reserved.
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Assessing the relevance of ecotoxicological studies for regulatory decision making.
Rudén, Christina; Adams, Julie; Ågerstrand, Marlene; Brock, Theo Cm; Poulsen, Veronique; Schlekat, Christian E; Wheeler, James R; Henry, Tala R
2017-07-01
Regulatory policies in many parts of the world recognize either the utility of or the mandate that all available studies be considered in environmental or ecological hazard and risk assessment (ERA) of chemicals, including studies from the peer-reviewed literature. Consequently, a vast array of different studies and data types need to be considered. The first steps in the evaluation process involve determining whether the study is relevant to the ERA and sufficiently reliable. Relevance evaluation is typically performed using existing guidance but involves application of "expert judgment" by risk assessors. In the present paper, we review published guidance for relevance evaluation and, on the basis of the practical experience within the group of authors, we identify additional aspects and further develop already proposed aspects that should be considered when conducting a relevance assessment for ecotoxicological studies. From a regulatory point of view, the overarching key aspect of relevance concerns the ability to directly or indirectly use the study in ERA with the purpose of addressing specific protection goals and ultimately regulatory decision making. Because ERA schemes are based on the appropriate linking of exposure and effect estimates, important features of ecotoxicological studies relate to exposure relevance and biological relevance. Exposure relevance addresses the representativeness of the test substance, environmental exposure media, and exposure regime. Biological relevance deals with the environmental significance of the test organism and the endpoints selected, the ecological realism of the test conditions simulated in the study, as well as a mechanistic link of treatment-related effects for endpoints to the protection goal identified in the ERA. In addition, uncertainties associated with relevance should be considered in the assessment. A systematic and transparent assessment of relevance is needed for regulatory decision making. The relevance aspects also need to be considered by scientists when designing, performing, and reporting ecotoxicological studies to facilitate their use in ERA. Integr Environ Assess Manag 2017;13:652-663. © 2016 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC). © 2016 The Authors. Integrated Environmental Assessment and Management Published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
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NASA Astrophysics Data System (ADS)
Beltrao, J.; Costa, M.; Rosado, V.; Gamito, P.; Santos, R.; Khaydarova, V.
2003-04-01
Due to the lack water around the Mediterranean regions, potable water luxurious uses - as in golf courses - are increasingly contested. In order to solve this problem, non conventional water resources (effluent, gray, recycled, reclaimed, brackish), like treated wastewater, for irrigation gained increasing role in the planning and development of additional water supplies in golf courses. In most cases, the intense use of effluent for irrigation attracted public awareness in respect of contaminating pathogens and heavy metals. The contaminating effect of salinity in soil and underground water is very often neglected. The objective of this work is to present the conventional techniques to control salinity of treated wastewater and to present some results on new clean techniques to solve this problem, in the framework of the INCO-COPERNICUS project (no. IC-15CT98-0105) "Adaptation of Efficient Water Use Criteria in Marginal Regions of Europe and Middle Asia with Scarce Sources Subject to Environmental Control, Climate Change and Socio-Economic Development" and of the INCO-DC project (no. IC18-CT98-0266) "Control of Salination and Combating Desertification Effects in the Mediterranean Region. Phase II". Saline water is the most common irrigation water in arid climates. Moreover, for each region treated wastewater is always more saline than tap water, and therefore, when treated wastewater is reused in golf courses, more salinity problems occur. Conventional techniques to combat the salination process in golf courses can be characterized by four generations: 1) Problem of root zone salination by soil leaching - two options can occur - when there is an impermeable layer, salts will be concentrated above this layer; on the other hand, when there is no impermeable layer, aquifers contamination can be observed; 2) Use of subsurface trickle irrigation - economy of water, and therefore less additional salts; however the problem of groundwater contamination due to natural rain or artificial leaching remained; 3) Enhanced fertilization increases turfgrass tolerance to salinity, but the contamination will be increased by other hazardous chemicals such as nitrate; 4) Use of salt tolerant turfgrass species this technique will be very useful to the plants, but does not solve the problem os soil or groundwater contamination. When reusing treated wastewater in the Mediterranean areas, the only way to control the salination process and to maintain the sustainability of golf courses is to combat the salination problems by environmentally safe and clean techniques. These new clean techniques include: 1) Use of salt removing turfgrass species; 2) Use of drought tolerant turfgrass species - reduction of salt application by deficit irrigation; 3) Reuse of minimal levels of wastewater enough to obtain a good visual appearance GVA of the turfgrass. Regarding these new clean techniques, experiments were carried out in golf courses of Algarve, Portugal, the most southwest part of Europe. It was shown: 1) Use of salt removing turfgrass species - 3 sprinkle irrigated cultivars were studied (Agrostis solonífera L.; Cynodon dactylon, L. and Penninsetum clandestinum Hochst ex Chiov). 2) Use of drought tolerant turfgrass species -responses to several levels of sprinkle irrigation wastewater and potable water (with and without fertilization). An experimental design, known as sprinkle point source was specially used to simulate the several levels of water application, expressed by the crop coefficient kc and by the crop evapotranspiration rate ETc. Turfgrass yield was enhanced linearly with the increased application of treated wastewater. 3) Reuse of minimal levels of wastewater enough to obtain a good visual appearance GVA of the turfgrass - The minimal crop coefficient kc for a good visual appearance GVA of the turfgrass was around 1.0 to potable water irrigated mixed cultivars (with 30 kg nitrogen ha-1 month-1) and 1.2 to wastewater irrigated Bermuda grass (without any mineral fertilization). As concluding remarks, our results show that these new clean techniques are a strong and powerful tool to control salinity and to avoid soil salination and to maintain sustainability of golf courses.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Berg, Michael Vanden; Anderson, Paul; Wallace, Janae
Saline water disposal is one of the most pressing issues with regard to increasing petroleum and natural gas production in the Uinta Basin of northeastern Utah. Conventional oil fields in the basin provide 69 percent of Utah?s total crude oil production and 71 percent of Utah?s total natural gas, the latter of which has increased 208% in the past 10 years. Along with hydrocarbons, wells in the Uinta Basin produce significant quantities of saline water ? nearly 4 million barrels of saline water per month in Uintah County and nearly 2 million barrels per month in Duchesne County. As hydrocarbonmore » production increases, so does saline water production, creating an increased need for economic and environmentally responsible disposal plans. Current water disposal wells are near capacity, and permitting for new wells is being delayed because of a lack of technical data regarding potential disposal aquifers and questions concerning contamination of freshwater sources. Many companies are reluctantly resorting to evaporation ponds as a short-term solution, but these ponds have limited capacity, are prone to leakage, and pose potential risks to birds and other wildlife. Many Uinta Basin operators claim that oil and natural gas production cannot reach its full potential until a suitable, long-term saline water disposal solution is determined. The enclosed project was divided into three parts: 1) re-mapping the base of the moderately saline aquifer in the Uinta Basin, 2) creating a detailed geologic characterization of the Birds Nest aquifer, a potential reservoir for large-scale saline water disposal, and 3) collecting and analyzing water samples from the eastern Uinta Basin to establish baseline water quality. Part 1: Regulators currently stipulate that produced saline water must be disposed of into aquifers that already contain moderately saline water (water that averages at least 10,000 mg/L total dissolved solids). The UGS has re-mapped the moderately saline water boundary in the subsurface of the Uinta Basin using a combination of water chemistry data collected from various sources and by analyzing geophysical well logs. By re-mapping the base of the moderately saline aquifer using more robust data and more sophisticated computer-based mapping techniques, regulators now have the information needed to more expeditiously grant water disposal permits while still protecting freshwater resources. Part 2: Eastern Uinta Basin gas producers have identified the Birds Nest aquifer, located in the Parachute Creek Member of the Green River Formation, as the most promising reservoir suitable for large-volume saline water disposal. This aquifer formed from the dissolution of saline minerals that left behind large open cavities and fractured rock. This new and complete understanding the aquifer?s areal extent, thickness, water chemistry, and relationship to Utah?s vast oil shale resource will help operators and regulators determine safe saline water disposal practices, directly impacting the success of increased hydrocarbon production in the region, while protecting potential future oil shale production. Part 3: In order to establish a baseline of water quality on lands identified by the U.S. Bureau of Land Management as having oil shale development potential in the southeastern Uinta Basin, the UGS collected biannual water samples over a three-year period from near-surface aquifers and surface sites. The near-surface and relatively shallow groundwater quality information will help in the development of environmentally sound water-management solutions for a possible future oil shale and oil sands industry and help assess the sensitivity of the alluvial and near-surface bedrock aquifers. This multifaceted study will provide a better understanding of the aquifers in Utah?s Uinta Basin, giving regulators the tools needed to protect precious freshwater resources while still allowing for increased hydrocarbon production.« less
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An Equation of State for Hypersaline Water in Great Salt Lake, Utah, USA
Naftz, D.L.; Millero, F.J.; Jones, B.F.; Green, W.R.
2011-01-01
Great Salt Lake (GSL) is one of the largest and most saline lakes in the world. In order to accurately model limnological processes in GSL, hydrodynamic calculations require the precise estimation of water density (??) under a variety of environmental conditions. An equation of state was developed with water samples collected from GSL to estimate density as a function of salinity and water temperature. The ?? of water samples from the south arm of GSL was measured as a function of temperature ranging from 278 to 323 degrees Kelvin (oK) and conductivity salinities ranging from 23 to 182 g L-1 using an Anton Paar density meter. These results have been used to develop the following equation of state for GSL (?? = ?? 0.32 kg m-3): ?? - ??0 = 184.01062 + 1.04708 * S - 1.21061*T + 3.14721E - 4*S2 + 0.00199T2 where ??0 is the density of pure water in kg m-3, S is conductivity salinity g L-1, and T is water temperature in degrees Kelvin. ?? 2011 U.S. Government.
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Cold and Hot Extremozymes: Industrial Relevance and Current Trends
Sarmiento, Felipe; Peralta, Rocío; Blamey, Jenny M.
2015-01-01
The development of enzymes for industrial applications relies heavily on the use of microorganisms. The intrinsic properties of microbial enzymes, e.g., consistency, reproducibility, and high yields along with many others, have pushed their introduction into a wide range of products and industrial processes. Extremophilic microorganisms represent an underutilized and innovative source of novel enzymes. These microorganisms have developed unique mechanisms and molecular means to cope with extreme temperatures, acidic and basic pH, high salinity, high radiation, low water activity, and high metal concentrations among other environmental conditions. Extremophile-derived enzymes, or extremozymes, are able to catalyze chemical reactions under harsh conditions, like those found in industrial processes, which were previously not thought to be conducive for enzymatic activity. Due to their optimal activity and stability under extreme conditions, extremozymes offer new catalytic alternatives for current industrial applications. These extremozymes also represent the cornerstone for the development of environmentally friendly, efficient, and sustainable industrial technologies. Many advances in industrial biocatalysis have been achieved in recent years; however, the potential of biocatalysis through the use of extremozymes is far from being fully realized. In this article, the adaptations and significance of psychrophilic, thermophilic, and hyperthermophilic enzymes, and their applications in selected industrial markets will be reviewed. Also, the current challenges in the development and mass production of extremozymes as well as future prospects and trends for their biotechnological application will be discussed. PMID:26539430
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INDICATORS OF UV EXPOSURE IN CORAL AND THEIR RELEVANCE TO GLOBAL CLIMATE CHANGE AND CORAL BLEACHING
A compelling aspect of the deterioration of coral reefs is the phenomenon of coral bleaching. Bleaching can destroy large areas of a reef with limited recovery or recruitment, and it may be induced by a variety of stressors ranging from exposure to temperature and salinity extrem...
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Yan, Lulu; Su, Jiaqi; Wang, Zhaoping; Yan, Xiwu; Yu, Ruihai; Ma, Peizhen; Li, Yangchun; Du, Junpeng
2017-01-01
Hybrid oysters often show heterosis in growth rate, weight, survival and adaptability to extremes of salinity. Oysters have also been used as model organisms to study the evolution of host-defense system. To gain comprehensive knowledge about various physiological processes in hybrid oysters under low salinity stress, we performed transcriptomic analysis of gill tissue of Crassostrea sikamea ♀ × Crassostrea angulata♂ hybrid using the deep-sequencing platform Illumina HiSeq. We exploited the high-throughput technique to delineate differentially expressed genes (DEGs) in oysters maintained in hypotonic conditions. A total of 199,391 high quality unigenes, with average length of 644 bp, were generated. Of these 35 and 31 genes showed up- and down-regulation, respectively. Functional categorization and pathway analysis of these DEGs revealed enrichment for immune mechanism, apoptosis, energy metabolism and osmoregulation under low salinity stress. The expression patterns of 41 DEGs in hybrids and their parental species were further analyzed by quantitative real-time PCR (qRT-PCR). This study will serve as a platform for subsequent gene expression analysis regarding environmental stress. Our findings will also provide valuable information about gene expression to better understand the immune mechanism, apoptosis, energy metabolism and osmoregulation in hybrid oysters under low salinity stress.
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Yan, Lulu; Su, Jiaqi; Wang, Zhaoping; Yan, Xiwu; Yu, Ruihai; Ma, Peizhen; Li, Yangchun; Du, Junpeng
2017-01-01
Hybrid oysters often show heterosis in growth rate, weight, survival and adaptability to extremes of salinity. Oysters have also been used as model organisms to study the evolution of host-defense system. To gain comprehensive knowledge about various physiological processes in hybrid oysters under low salinity stress, we performed transcriptomic analysis of gill tissue of Crassostrea sikamea ♀ × Crassostrea angulata♂ hybrid using the deep-sequencing platform Illumina HiSeq. We exploited the high-throughput technique to delineate differentially expressed genes (DEGs) in oysters maintained in hypotonic conditions. A total of 199,391 high quality unigenes, with average length of 644 bp, were generated. Of these 35 and 31 genes showed up- and down-regulation, respectively. Functional categorization and pathway analysis of these DEGs revealed enrichment for immune mechanism, apoptosis, energy metabolism and osmoregulation under low salinity stress. The expression patterns of 41 DEGs in hybrids and their parental species were further analyzed by quantitative real-time PCR (qRT-PCR). This study will serve as a platform for subsequent gene expression analysis regarding environmental stress. Our findings will also provide valuable information about gene expression to better understand the immune mechanism, apoptosis, energy metabolism and osmoregulation in hybrid oysters under low salinity stress. PMID:28182701
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Influence of predicted climage change elements on Z. ...
Global climate change (GCC) is expected to have pronounced impacts on estuarine and marine habitats including sea level rise, increased storm intensity, increased air and water temperatures, changes in upwelling dynamics and ocean acidification. All of these elements are likely to impact the growth and potential distribution of the non-indigenous seagrass Zostera japonica both within the State of Washington and within the region. Understanding how Z. japonica will respond to GCC requires a thorough understanding of plant physiology and predictions of GCC effects. Furthermore, Washington State is proposing to list Z. japonica as a “noxious weed” which will allow the state to use herbicide controls for management. We present data from manipulative experiments designed to better understand how Z. japonica photosynthetic physiology responds to temperature, salinity and light. We found that Z. japonica is well adapted to moderate temperatures and salinity with maximum photosynthesis of salinity of 20. The Coos Bay population had greater Pmax and saturation irradiance (Ik) than the Padilla bay population (p < 0.001) and tolerates daily exposure to both freshwater and marine water, suggesting that this population tolerates fairly extreme environmental fluctuations. Extreme temperatures (35 °C) were generally lethal to Z. japonica populations from Padilla, Coos and Yaquina Bays. High salinity (35) had lower mortality than either salinity of 5 or 20 (p = 0.0
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Tine, M; de Lorgeril, J; Panfili, J; Diop, K; Bonhomme, F; Durand, J-D
2007-07-01
The effects of salinity on the expression of genes coding for growth hormone (GH) and prolactin-1 (PRL1) were studied in various natural populations of the black-chinned tilapia Sarotherodon melanotheron from West Africa. Individuals were sampled in June 2005 in six locations in Senegal and the Gambia, at various salinities between 0 and 101. The poorest condition factors were recorded in the most saline sampling site and the best growth in the fish from a marine environment. The pituitary GH mRNA levels were significantly higher in fish adapted to seawater, whereas the PRL1 mRNA levels were highest in fish adapted to fresh- and brackish water. These results show that the PRL1 mRNA levels seem to reflect relatively well the differences in environmental salinity, in contrast to those of GH, which would tend instead to reflect the individual growth in each environment. However, no relation could be found between growth in the hypersaline areas and the expression profile of GH. Although the fish analysed were morphologically identical, the expression of genes coding for GH and PRL1 showed large differences between individuals. This inter-individual variation in gene expression remains poorly understood.
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From convection rolls to finger convection in double-diffusive turbulence
Verzicco, Roberto; Lohse, Detlef
2016-01-01
Double-diffusive convection (DDC), which is the buoyancy-driven flow with fluid density depending on two scalar components, is ubiquitous in many natural and engineering environments. Of great interests are scalars' transfer rate and flow structures. Here we systematically investigate DDC flow between two horizontal plates, driven by an unstable salinity gradient and stabilized by a temperature gradient. Counterintuitively, when increasing the stabilizing temperature gradient, the salinity flux first increases, even though the velocity monotonically decreases, before it finally breaks down to the purely diffusive value. The enhanced salinity transport is traced back to a transition in the overall flow pattern, namely from large-scale convection rolls to well-organized vertically oriented salt fingers. We also show and explain that the unifying theory of thermal convection originally developed by Grossmann and Lohse for Rayleigh–Bénard convection can be directly applied to DDC flow for a wide range of control parameters (Lewis number and density ratio), including those which cover the common values relevant for ocean flows. PMID:26699474
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NASA Astrophysics Data System (ADS)
Wiegers, Carla Elisabeth; Schäfer, Dirk
2015-06-01
In areas where the geological subsurface is used for storage of gases or fracking, there is a risk of saline formation water entering protected aquifers. The impact of such potential leakage therefore needs to be evaluated at relevant sites to develop practical monitoring concepts. Three-dimensional numerical simulations and a sensitivity analysis are performed to determine the influence of aquifer parameters, ground water flow, aquifer morphology, leakage rate and NaCl-concentration of the intruding water on the propagation behaviour of saline water. Two example scenarios were simulated based on a realistic site-scale conceptual model, one with water from the lower Braunkohlensande, (NaCl = 7.61 g/l) the other with saline water from the Bunter sandstone formation (NaCl = 280.3 g/l). The simulations show that saltwater migrates along the bottom of the aquifer, and that groundwater flow can dominate the transport of chloride. In this case the spreading of denser water is not influenced by the aquifer's morphology.
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Effects of chilling temperatures on photosynthesis
USDA-ARS?s Scientific Manuscript database
Environmental stress is an inescapable reality for most plants growing in natural settings. Conditions of sub or supra-optimal temperatures, water deficit, water logging, salinity, and pollution can have dramatic effects on plant growth and development, and in agricultural settings, yield. In cotton...
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Salt Power: Is Neptune's Ole Salt a Tiger in the Tank?
ERIC Educational Resources Information Center
Wick, Gerry Shishin
1979-01-01
Discussed is the utilization of salinity-gradient energy as a potential source of power. Detailed are the scientific principles, potential sources, latest research, and environmental effects associated with this alternative energy source. The future prospects are addressed. (BT)
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Halophytes: Potential Resources for Salt Stress Tolerance Genes and Promoters
Mishra, Avinash; Tanna, Bhakti
2017-01-01
Halophytes have demonstrated their capability to thrive under extremely saline conditions and thus considered as one of the best germplasm for saline agriculture. Salinity is a worldwide problem, and the salt-affected areas are increasing day-by-day because of scanty rainfall, poor irrigation system, salt ingression, water contamination, and other environmental factors. The salinity stress tolerance mechanism is a very complex phenomenon, and some pathways are coordinately linked for imparting salinity tolerance. Though a number of salt responsive genes have been reported from the halophytes, there is always a quest for promising stress-responsive genes that can modulate plant physiology according to the salt stress. Halophytes such as Aeluropus, Mesembryanthemum, Suaeda, Atriplex, Thellungiella, Cakile, and Salicornia serve as a potential candidate for the salt-responsive genes and promoters. Several known genes like antiporters (NHX, SOS, HKT, VTPase), ion channels (Cl−, Ca2+, aquaporins), antioxidant encoding genes (APX, CAT, GST, BADH, SOD) and some novel genes such as USP, SDR1, SRP etc. were isolated from halophytes and explored for developing stress tolerance in the crop plants (glycophytes). It is evidenced that stress triggers salt sensors that lead to the activation of stress tolerance mechanisms which involve multiple signaling proteins, up- or down-regulation of several genes, and finally the distinctive or collective effects of stress-responsive genes. In this review, halophytes are discussed as an excellent platform for salt responsive genes which can be utilized for developing salinity tolerance in crop plants through genetic engineering. PMID:28572812
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Röthig, Till; Ochsenkühn, Michael A; Roik, Anna; van der Merwe, Riaan; Voolstra, Christian R
2016-03-01
Scleractinian corals are assumed to be stenohaline osmoconformers, although they are frequently subjected to variations in seawater salinity due to precipitation, freshwater run-off and other processes. Observed responses to altered salinity levels include differences in photosynthetic performance, respiration and increased bleaching and mortality of the coral host and its algal symbiont, but a study looking at bacterial community changes is lacking. Here, we exposed the coral Fungia granulosa to strongly increased salinity levels in short- and long-term experiments to disentangle temporal and compartment effects of the coral holobiont (i.e. coral host, symbiotic algae and associated bacteria). Our results show a significant reduction in calcification and photosynthesis, but a stable microbiome after short-term exposure to high-salinity levels. By comparison, long-term exposure yielded unchanged photosynthesis levels and visually healthy coral colonies indicating long-term acclimation to high-salinity levels that were accompanied by a major coral microbiome restructuring. Importantly, a bacterium in the family Rhodobacteraceae was succeeded by Pseudomonas veronii as the numerically most abundant taxon. Further, taxonomy-based functional profiling indicates a shift in the bacterial community towards increased osmolyte production, sulphur oxidation and nitrogen fixation. Our study highlights that bacterial community composition in corals can change within days to weeks under altered environmental conditions, where shifts in the microbiome may enable adjustment of the coral to a more advantageous holobiont composition. © 2016 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.
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Halophytes: Potential Resources for Salt Stress Tolerance Genes and Promoters.
Mishra, Avinash; Tanna, Bhakti
2017-01-01
Halophytes have demonstrated their capability to thrive under extremely saline conditions and thus considered as one of the best germplasm for saline agriculture. Salinity is a worldwide problem, and the salt-affected areas are increasing day-by-day because of scanty rainfall, poor irrigation system, salt ingression, water contamination, and other environmental factors. The salinity stress tolerance mechanism is a very complex phenomenon, and some pathways are coordinately linked for imparting salinity tolerance. Though a number of salt responsive genes have been reported from the halophytes, there is always a quest for promising stress-responsive genes that can modulate plant physiology according to the salt stress. Halophytes such as Aeluropus, Mesembryanthemum, Suaeda, Atriplex, Thellungiella, Cakile , and Salicornia serve as a potential candidate for the salt-responsive genes and promoters. Several known genes like antiporters ( NHX, SOS, HKT, VTPase ), ion channels (Cl - , Ca 2+ , aquaporins), antioxidant encoding genes ( APX, CAT, GST, BADH, SOD ) and some novel genes such as USP, SDR1, SRP etc. were isolated from halophytes and explored for developing stress tolerance in the crop plants (glycophytes). It is evidenced that stress triggers salt sensors that lead to the activation of stress tolerance mechanisms which involve multiple signaling proteins, up- or down-regulation of several genes, and finally the distinctive or collective effects of stress-responsive genes. In this review, halophytes are discussed as an excellent platform for salt responsive genes which can be utilized for developing salinity tolerance in crop plants through genetic engineering.
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NASA Astrophysics Data System (ADS)
Haddout, Soufiane; Maslouhi, Abdellatif; Magrane, Bouchaib
2018-02-01
Estuaries, which are coastal bodies of water connecting the riverine and marine environment, are among the most important ecosystems in the world. Saltwater intrusion is the movement of coastal saline water into an estuary, which makes up-estuary water, that becomes salty due to the mixing of freshwater with saltwater. It has become a serious environmental problem in the Sebou estuary (Morocco) during wet and dry seasons, which have a considerable impact on residential water supply, agricultural water supply as well as urban industrial production. The variations of salt intrusion, and the vertical stratification under different river flow conditions in the Sebou estuary were investigated in this paper using a two-dimensional numerical model. The model was calibrated and verified against water level variation, and salinity variation during 2016, respectively. Additionally, the model validation process showed that the model results fit the observed data fairly well ( R2 > 0.85, NSC > 0.89 and RMSE = 0.26 m). Model results show that freshwater is a dominant influencing factor to the saltwater intrusion and controlled salinity structure, vertical stratification and length of the saltwater intrusion. Additionally, the extent of salinity intrusion depends on the balance between fresh water discharges and saltwater flow from the sea. This phenomenon can be reasonably predicted recurring to mathematical models supported by monitored data. These tools can be used to quantify how much fresh water is required to counterbalance salinity intrusion at the upstream water intakes.
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Durako, Michael J.; Howarth, Jacqueline F.
2017-01-01
Thalassia testudinum (turtle grass) is the dominant and climax-successional seagrass species in the subtropical/tropical Atlantic and Caribbean region. Two die-offs of T. testudinum in Florida Bay, United States have raised concerns regarding the resilience of this species to environmental disturbances. Seedlings are important in recovery of T. testudinum, following disturbance events. Leaf spectral reflectance [R(λ)] was measured in T. testudinum seedlings exposed for 2 weeks to three salinities (20, 35, and 50) and two light levels (full sun and 50–70% light reduction) in experimental mesocosms. Multivariate analyses indicated that hypersalinity had a greater effect on spectral reflectance than hyposalinity or light reduction. There was an increase in variability and flattening of reflectance spectra at the highest salinity. All three salinity treatments had distinct reflectance spectra across green wavelengths (530–580 nm), with additional discrimination between 20 versus 50 and 35 versus 50 treatments across red wavelengths (630–690 nm). Red:Green reflectance ratios were highest and photochemical reflective index values were lowest for the salinity 50 treatment, but were not significantly different between the salinity 20 and 35 treatments. The changes in the R(λ) spectra for the salinity 50 seedlings were consistent with previously observed reductions in leaf pigments and maximum photochemical efficiency of photosystem II. These observations indicate that leaf spectral reflectance is a sensitive indicator of plant stress in T. testudinum seedlings and that seedlings are more sensitive to short-term exposures to hypersalinity than hyposalinity. PMID:28702044
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Durako, Michael J; Howarth, Jacqueline F
2017-01-01
Thalassia testudinum (turtle grass) is the dominant and climax-successional seagrass species in the subtropical/tropical Atlantic and Caribbean region. Two die-offs of T. testudinum in Florida Bay, United States have raised concerns regarding the resilience of this species to environmental disturbances. Seedlings are important in recovery of T. testudinum , following disturbance events. Leaf spectral reflectance [ R (λ)] was measured in T. testudinum seedlings exposed for 2 weeks to three salinities (20, 35, and 50) and two light levels (full sun and 50-70% light reduction) in experimental mesocosms. Multivariate analyses indicated that hypersalinity had a greater effect on spectral reflectance than hyposalinity or light reduction. There was an increase in variability and flattening of reflectance spectra at the highest salinity. All three salinity treatments had distinct reflectance spectra across green wavelengths (530-580 nm), with additional discrimination between 20 versus 50 and 35 versus 50 treatments across red wavelengths (630-690 nm). Red:Green reflectance ratios were highest and photochemical reflective index values were lowest for the salinity 50 treatment, but were not significantly different between the salinity 20 and 35 treatments. The changes in the R (λ) spectra for the salinity 50 seedlings were consistent with previously observed reductions in leaf pigments and maximum photochemical efficiency of photosystem II. These observations indicate that leaf spectral reflectance is a sensitive indicator of plant stress in T. testudinum seedlings and that seedlings are more sensitive to short-term exposures to hypersalinity than hyposalinity.
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Yang, Xin-guo; Song, Nai-ping
2011-09-01
By the methods of controlled and typical sampling, this paper analyzed the texture, salinization characteristics, cation exchange capacity (CEC), and their correlations in the 0-40 cm soil profiles of corn land, medlar land, and non-utilized land in Yanghuang irrigated area of Hongsipu, Northwest China. Under controlled sampling, the salt content in the soil profiles was 0.69-1.30 g x kg(-1) (except in non-utilized land where the 0-10 cm soil salt content was up to 1.74 g x kg(-1)), with no obvious salinization. The sodium adsorption ratio and exchangeable sodium percentage in the 20-40 cm soil layer of medlar land were 12.18 and 14.1%, respectively, and the total content of clay and silt in the 0-40 cm soil profile of medlar land was up to 37.3% whereas that in the 0-20 cm soil layer of corn land was only 13.5%. In the 20-40 cm soil layer of corn land, the indices of sandy desertification and salinization had significant correlations under controlled sampling but no correlations under typical sampling, while the CEC and the sandy desertification and salinization indices had significant correlations under typical sampling. In different land use types in the study area, soil sandy desertification and salinization had complicated interrelationships, and CEC could be used as the indicator for the changes in soil environmental quality.
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The Water-Energy-Food Nexus in Kazakhstan: Trends and Analyses
NASA Astrophysics Data System (ADS)
Karatayev, Marat; Rivotti, Pedro; Sobral Mourão, Zenaida; Konadu, D. Dennis; Clarke, Michèle
2017-04-01
The concept of the water, energy and food nexus is extremely relevant to Kazakhstan as the country faces population growth, economic progress and environmental challenges such as water scarcity, desertification, and climate change. Furthermore, poor sectoral coordination and institutional fragmentation have caused an unsustainable resource use and threaten the long-term sustainability of water, energy and food security in Kazakhstan. Specifically, low tariffs in the water and electricity sectors have led to under-investment in water and energy efficiency measures, leading to extensive water losses, soil salinity, as well as degradation of agricultural land. Using the nexus approach, this study aims to investigate and map the linkages between water resources, energy production and food security in Kazakhstan, with an emphasis on the current coordination framework. This will enable the identification of critical interdependency issues in the management of these resources. The results will provide a better understanding of the current interconnectedness of the sectors, and support the coordination of decision-making at various levels of governance and research of land, water and energy to meet sustainable development goals.
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Continuous water quality monitoring for the hard clam industry in Florida, USA.
Bergquist, Derk C; Heuberger, David; Sturmer, Leslie N; Baker, Shirley M
2009-01-01
In 2000, Florida's fast-growing hard clam aquaculture industry became eligible for federal agricultural crop insurance through the US Department of Agriculture, but the responsibility for identifying the cause of mortality remained with the grower. Here we describe the continuous water quality monitoring system used to monitor hard clam aquaculture areas in Florida and show examples of the data collected with the system. Systems recording temperature, salinity, dissolved oxygen, water depth, turbidity and chlorophyll at 30 min intervals were installed at 10 aquaculture lease areas along Florida's Gulf and Atlantic coasts. Six of these systems sent data in real-time to a public website, and all 10 systems provided data for web-accessible archives. The systems documented environmental conditions that could negatively impact clam survival and productivity and identified biologically relevant water quality differences among clam aquaculture areas. Both the real-time and archived data were used widely by clam growers and nursery managers to make management decisions and in filing crop loss insurance claims. While the systems were labor and time intensive, we recommend adjustments that could reduce costs and staff time requirements.
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Dissolved organic matter dynamics in the oligo/meso-haline zone of wetland-influenced coastal rivers
NASA Astrophysics Data System (ADS)
Maie, Nagamitsu; Sekiguchi, Satoshi; Watanabe, Akira; Tsutsuki, Kiyoshi; Yamashita, Youhei; Melling, Lulie; Cawley, Kaelin M.; Shima, Eikichi; Jaffé, Rudolf
2014-08-01
Wetlands are key components in the global carbon cycle and export significant amounts of terrestrial carbon to the coastal oceans in the form of dissolved organic carbon (DOC). Conservative behavior along the salinity gradient of DOC and chromophoric dissolved organic matter (CDOM) has often been observed in estuaries from their freshwater end-member (salinity = 0) to the ocean (salinity = 35). While the oligo/meso-haline (salinity < 10) tidal zone of upper estuaries has been suggested to be more complex and locally influenced by geomorphological and hydrological features, the environmental dynamics of dissolved organic matter (DOM) and the environmental drivers controlling its source, transport, and fate have scarcely been evaluated. Here, we investigated the distribution patterns of DOC and CDOM optical properties determined by UV absorbance at 254 nm (A254) and excitation-emission matrix (EEM) fluorescence coupled with parallel factor analysis (PARAFAC) along the lower salinity range (salinity < 10) of the oligo/meso-haline zone for three distinct wetland-influenced rivers; namely the Bekanbeushi River, a cool-temperate river with estuarine lake in Hokkaido, Japan, the Harney River, a subtropical river with tidally-submerged mangrove fringe in Florida, USA, and the Judan River, a small, acidic, tropical rainforest river in Borneo, Malaysia. For the first two rivers, a clear decoupling between DOC and A254 was observed, while these parameters showed similar conservative behavior for the third. Three distinct EEM-PARAFAC models established for each of the rivers provided similar spectroscopic characteristics except for some unique fluorescence features observed for the Judan River. The distribution patterns of PARAFAC components suggested that the inputs from plankton and/or submerged aquatic vegetation can be important in the Bekanbeushi River. Further, DOM photo-products formed in the estuarine lake were also found to be transported upstream. In the Harney River, whereas upriver-derived terrestrial humic-like components were mostly distributed conservatively, some of these components were also derived from mangrove inputs in the oligo/meso-haline zone. Interestingly, fluorescence intensities of some terrestrial humic-like components increased with salinity for the Judan River possibly due to changes in the dissociation state of acidic functional groups and/or increase in the fluorescence quantum yield along the salinity gradient. The protein-like and microbial humic-like components were distributed differently between three wetland rivers, implying that interplay between loss to microbial degradation and inputs from diverse sources are different for the three wetland-influenced rivers. The results presented here indicate that upper estuarine oligo/meso-haline regions of coastal wetland rivers are highly dynamic with regard to the biogeochemical behavior of DOM.
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NASA Astrophysics Data System (ADS)
van Soelen, Elsbeth E.; Twitchett, Richard J.; Kürschner, Wolfram M.
2018-04-01
The late Permian biotic crisis had a major impact on marine and terrestrial environments. Rising CO2 levels following Siberian Trap volcanic activity were likely responsible for expanding marine anoxia and elevated water temperatures. This study focuses on one of the stratigraphically most expanded Permian-Triassic records known, from Jameson Land, East Greenland. High-resolution sampling allows for a detailed reconstruction of the changing environmental conditions during the extinction event and the development of anoxic water conditions. Since very little is known about how salinity was affected during the extinction event, we especially focus on the aquatic palynomorphs and infer changes in salinity from changes in the assemblage and morphology. The start of the extinction event, here defined by a peak in spore : pollen, indicating disturbance and vegetation destruction in the terrestrial environment, postdates a negative excursion in the total organic carbon, but predates the development of anoxia in the basin. Based on the newest estimations for sedimentation rates, the marine and terrestrial ecosystem collapse took between 1.6 and 8 kyr, a much shorter interval than previously estimated. The palynofacies and palynomorph records show that the environmental changes can be explained by enhanced run-off and increased primary productivity and water column stratification. A lowering in salinity is supported by changes in the acritarch morphology. The length of the processes of the acritarchs becomes shorter during the extinction event and we propose that these changes are evidence for a reduction in salinity in the shallow marine setting of the study site. This inference is supported by changes in acritarch distribution, which suggest a change in palaeoenvironment from open marine conditions before the start of the extinction event to more nearshore conditions during and after the crisis. In a period of sea-level rise, such a reduction in salinity can only be explained by increased run-off. High amounts of both terrestrial and marine organic fragments in the first anoxic layers suggest that high run-off, increased nutrient availability, possibly in combination with soil erosion, are responsible for the development of anoxia in the basin. Enhanced run-off could result from changes in the hydrological cycle during the late Permian extinction event, which is a likely consequence of global warming. In addition, vegetation destruction and soil erosion may also have resulted in enhanced run-off. Salinity stratification could potentially explain the development of anoxia in other shallow marine sites. The input of freshwater and related changes in coastal salinity could also have implications for the interpretation of oxygen isotope records and seawater temperature reconstructions at some sites.
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Effects of environmental changes on marsh vegetation with special reference to salinity
NASA Technical Reports Server (NTRS)
Smalley, A. E.; Thien, L. B.
1976-01-01
A literature survey primarily concerned with brackish and salt marshes located along the eastern coast of North America and the Gulf Coast was presented. The review concentrated upon the vegetation of the marshes, particularly in regard to distribution, composition, succession, and productivity. Special efforts were made to include major works concerned with the Louisiana and Mississipi coastal marshes. It appears that spring to early summer (weeks 18-34 of the year; April - mid-July) is the best period of time to categorize the communities. It is during this time of the year that the communities appear most stable in regard to species composition. This allows a strong correlation to be drawn between the salinity of the region and the dominant species of the community. As such, this would seem to be best period in which to sample the marsh via air or land for differences in vegetation and salinity.
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Nutrient Enrichment Increases Mortality of Mangroves
Lovelock, Catherine E.; Ball, Marilyn C.; Martin, Katherine C.; C. Feller, Ilka
2009-01-01
Nutrient enrichment of the coastal zone places intense pressure on marine communities. Previous studies have shown that growth of intertidal mangrove forests is accelerated with enhanced nutrient availability. However, nutrient enrichment favours growth of shoots relative to roots, thus enhancing growth rates but increasing vulnerability to environmental stresses that adversely affect plant water relations. Two such stresses are high salinity and low humidity, both of which require greater investment in roots to meet the demands for water by the shoots. Here we present data from a global network of sites that documents enhanced mortality of mangroves with experimental nutrient enrichment at sites where high sediment salinity was coincident with low rainfall and low humidity. Thus the benefits of increased mangrove growth in response to coastal eutrophication is offset by the costs of decreased resilience due to mortality during drought, with mortality increasing with soil water salinity along climatic gradients. PMID:19440554
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Nutrient enrichment increases mortality of mangroves.
Lovelock, Catherine E; Ball, Marilyn C; Martin, Katherine C; C Feller, Ilka
2009-01-01
Nutrient enrichment of the coastal zone places intense pressure on marine communities. Previous studies have shown that growth of intertidal mangrove forests is accelerated with enhanced nutrient availability. However, nutrient enrichment favours growth of shoots relative to roots, thus enhancing growth rates but increasing vulnerability to environmental stresses that adversely affect plant water relations. Two such stresses are high salinity and low humidity, both of which require greater investment in roots to meet the demands for water by the shoots. Here we present data from a global network of sites that documents enhanced mortality of mangroves with experimental nutrient enrichment at sites where high sediment salinity was coincident with low rainfall and low humidity. Thus the benefits of increased mangrove growth in response to coastal eutrophication is offset by the costs of decreased resilience due to mortality during drought, with mortality increasing with soil water salinity along climatic gradients.
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NASA Astrophysics Data System (ADS)
Jyothibabu, R.; Win, Ni Ni; Shenoy, D. M.; Swe, U. Tint; Pratik, M.; Thwin, Swe; Jagadeesan, L.
2014-11-01
The northern Andaman Sea including the Myanmar waters is one of the least studied regions of the northern Indian Ocean. The freshwater and suspended sediments carried by Ayeyawady/Irrawaddy, the peculiar surface circulation, coastline morphology and shallow bathymetry in the Gulf of Mottama facilitate several diverse environmental settings in the study region. In order to understand the environmental settings and their linkages to the plankton community in the study region, this paper combined in situ data of 'First India-Myanmar Joint Oceanographic Expedition' with satellite oceanography observations. The study period was the Spring Intermonsoon (March-May), which was characterized by high tidal activity in the Gulf of Mottama region (tidal height 6-8 m) causing strong tidal currents and re-suspension of sediments. The tidal currents and eastward advection of Ayeyawady influx caused the lowest salinity, highest concentration of nutrients, suspended sediments and chlorophyll a in the Gulf of Mottama region. Conversely, high salinity, highest temperature, lowest nutrients and suspended sediments prevalent in the offshore waters of the northern Andaman Sea induced a massive bloom of Trichodesmium erythraeum, which was mostly in the declining phase during the observation. The in situ and satellite remote sensing data clearly showed that the T. erythraeum bloom observed in the offshore waters was closely linked to a warm core eddy. The decomposition of the bloom favored swarms of siphonophores and hydromedusae through a trophic link involving copepods and appendicularians. Aided by satellite remote sensing data and multivariate statistical tools, five diverse environmental settings have been identified in the study domain. The analysis showed a close coupling between phytoplankton biomass and nutrients with their higher values in the Gulf of Mottama, off Rakhine, Ayeyawady and Thanintharyi region as compared to the offshore waters in the northern Andaman Sea. The zooplankton community dominated by copepods and chaetognaths preferred regions with high salinity, chlorophyll, deep mixed layer and low suspended sediments as existed off Rakhine, Ayeyawady and Thanintharyi regions. The study evidences, for the first time, the spatial segregation of environmental settings and its linkages to the plankton community off Myanmar during the Spring Intermonsoon.
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Scheelbeek, Pauline F D; Khan, Aneire E; Mojumder, Sontosh; Elliott, Paul; Vineis, Paolo
2016-08-01
Coastal areas in Southeast Asia are experiencing high sodium concentrations in drinking water sources that are commonly consumed by local populations. Salinity problems caused by episodic cyclones and subsequent seawater inundations are likely (partly) related to climate change and further exacerbated by changes in upstream river flow and local land-use activities. Dietary (food) sodium plays an important role in the global burden of hypertensive disease. It remains unknown, however, if sodium in drinking water-rather than food-has similar effects on blood pressure and disease risk. In this study, we examined the effect of drinking water sodium on blood pressure of pregnant women: increases in blood pressure in this group could severely affect maternal and fetal health. Data on blood pressure, drinking water source, and personal, lifestyle, and environmental confounders was obtained from 701 normotensive pregnant women residing in coastal Bangladesh. Generalized linear mixed regression models were used to investigate association of systolic and diastolic blood pressure of these-otherwise healthy-women with their water source. After adjustment for confounders, drinkers of tube well and pond water (high saline sources) were found to have significantly higher average systolic (+4.85 and +3.62 mm Hg) and diastolic (+2.30 and +1.72 mm Hg) blood pressures than rainwater drinkers. Drinking water salinity problems are expected to exacerbate in the future, putting millions of coastal people-including pregnant women-at increased risk of hypertension and associated diseases. There is an urgent need to further explore the health risks associated to this understudied environmental health problem and feasibility of possible adaptation strategies. © 2016 American Heart Association, Inc.
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NASA Astrophysics Data System (ADS)
Huffaker, R.; Munoz-Carpena, R.
2016-12-01
There are increasing calls to audit decision-support models used for environmental policy to ensure that they correspond with the reality facing policy makers. Modelers can establish correspondence by providing empirical evidence of real-world dynamic behavior that their models skillfully simulate. We present a pre-modeling diagnostic framework—based on nonlinear dynamic analysis—for detecting and reconstructing real-world environmental dynamics from observed time-sequenced data. Phenomenological (data-driven) modeling—based on machine learning regression techniques—extracts a set of ordinary differential equations governing empirically-diagnosed system dynamics from a single time series, or from multiple time series on causally-interacting variables. We apply the framework to investigate saltwater intrusion into coastal wetlands in Everglades National Park, Florida, USA. We test the following hypotheses posed in the literature linking regional hydrologic variables with global climatic teleconnections: (1) Sea level in Florida Bay drives well level and well salinity in the coastal Everglades; (2) Atlantic Multidecadal Oscillation (AMO) drives sea level, well level and well salinity; and (3) AMO and (El Niño Southern Oscillation) ENSO bi-causally interact. The thinking is that salt water intrusion links ocean-surface salinity with salinity of inland water sources, and sea level with inland water; that AMO and ENSO share a teleconnective relationship (perhaps through the atmosphere); and that AMO and ENSO both influence inland precipitation and thus well levels. Our results support these hypotheses, and we successfully construct a parsimonious phenomenological model that reproduces diagnosed nonlinear dynamics and system interactions. We propose that reconstructed data dynamics be used, along with other expert information, as a rigorous benchmark to guide specification and testing of hydrologic decision support models corresponding with real-world behavior.
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Jonczyk, E; Gilron, G; Zajdlik, B
2001-04-01
Most industrial effluents discharged into the marine coastal environment are freshwater in nature and therefore require manipulation prior to testing with marine organisms. The sea urchin fertilization test is a common marine bioassay used for routine environmental monitoring, investigative evaluations, and/or regulatory testing of effluents and sediment pore waters. The existing Canadian and U.S. Environmental Protection Agencies test procedures using sea urchin (and sand dollar) gametes allow for sample salinity adjustment using either brine or dry salts. Moreover, these procedures also allow for the use of either natural or synthetic marine water for culturing/holding test organisms and for full-scale testing. At present, it is unclear to what extent these variables affect test results for whole effluents. The test methods simply state that there are no data available and that the use of artificial dry sea salts should be considered provisional. We conducted a series of concurrent experiments aimed at comparing the two different treatments of sample salinity adjustment and the use of natural versus synthetic seawater in order to test these assumptions and evaluate effects on the estimated end points generated by the sea urchin fertilization sublethal toxicity test. Results from these experiments indicated that there is no significant difference in test end points when dry salts or brine are used for sample salinity adjustment. Similarly, results obtained from parallel (split-sample) industrial effluent tests with natural and artificial seawater suggest that both dilution waters produce similar test results. However, data obtained from concurrent tests with the reference toxicant, copper sulfate, showed higher variability and greater sensitivity when using natural seawater as control/dilution water.
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Donmez, Z; Yigit, Ö; Bilici, S; Dursun, N; Gul, M; Dastan, S D; Uzun, H
2016-06-01
This study's aim was to investigate the effect of melatonin in terms of mitigating the effects of smoking on the laryngeal mucosa of rats exposed to environmental tobacco smoke. Rats were divided into four groups: Melatonin + Smoking group exposed to smoke with melatonin; Smoking group exposed to smoke without melatonin; Saline group not exposed to smoke without melatonin; Melatonin group not exposed to smoke with melatonin. CuZn-superoxide dismutase (CuZn-SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities were evaluated in plasma and tissues. Tissues were also examined the changes of squamous hyperplasia, keratosis, parakeratosis and epithelial hyperplasia by light microscope and the ultrastructural changes by electron microscope. Tissue SOD, CAT and GSH-Px activities were significantly higher in Saline and Melatonin groups than Melatonin + Smoking and Smoking groups. Plasma CuZn-SOD and CAT activities were significantly higher in Saline and Melatonin groups than Smoking group. Plasma GSH-Px showed no significant difference. The rate of epithelial hyperplasia was significantly higher in Smoking group than the other groups. The rate of parakeratosis was significantly higher in Smoking group than the other groups. The epithelial cells in Melatonin + Smoking group displayed, normal cell structure similar to those in Saline group under electron microscope. The study shows that smoking induces substantial pathological changes in the laryngeal mucosa and melatonin may have some beneficial effects in partially reversing smoking-induced laryngeal injury by inducing the expression of antioxidants; biochemical and histological outcomes also support these findings due to preventing tissue damage in laryngeal mucosa exposed to smoke. © 2015 John Wiley & Sons Ltd.
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Faulkner, P C; Burleson, M L; Simonitis, L; Marshall, C; Hala, D; Petersen, L H
2018-05-18
American alligator ( Alligator mississippiensis , Linnaeus) habitats are prone to saltwater intrusion following major storms, hurricanes or droughts. Anthropogenic impacts affecting hydrology of freshwater systems may exacerbate saltwater intrusion into freshwater habitats. The endocrine system of alligators is susceptible to changes in the environment but it is currently not known how the crocodilian physiological system responds to environmental stressors such as salinity. Juvenile alligators were exposed to 12‰ saltwater for 5 weeks to determine effects of chronic exposure to saline environments. Following 5 weeks, plasma levels of hormones (e.g., progesterone, testosterone, estradiol, corticosterone, aldosterone, angiotensin II) were quantified using LC-MS/MS. Compared to freshwater kept subjects, saltwater exposed alligators had significantly elevated plasma levels of corticosterone, 11-deoxycortisol, 17α-hydroxyprogesterone, testosterone, 17β-estradiol, estrone and estriol while pregnenolone and angiotensin II (ANG II) were significantly depressed and aldosterone (ALDO) levels were unchanged (slightly depressed). However, saltwater exposure did not affect gene expression of renal mineralo- and glucorticoid (MR, GR) and angiotensin type 1 (AT-1) receptors or morphology of lingual glands. On the other hand, saltwater exposure significantly reduced plasma glucose concentrations whereas parameters diagnostic of perturbed liver function (enzymes AST, ALT) and kidney function (creatinine, creatine kinase) were significantly elevated. Except for plasma potassium levels (K + ), plasma ions Na + and Cl - were significantly elevated in saltwater alligators. Overall, this study demonstrated significant endocrine and physiological effects in juvenile alligators chronically exposed to a saline environment. Results provide novel insights into the effects of a natural environmental stressor (salinity) on renin-angiotensin-aldosterone system and steroidogenesis of alligators. © 2018. Published by The Company of Biologists Ltd.
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NASA Astrophysics Data System (ADS)
Holmes, K. W.; Barrett-Lennard, E. G.; Altman, M.
2011-12-01
Experiments conducted under controlled conditions clearly show that the growth and survival of plants on saltland is affected by both the levels of salinity and waterlogging (or depth to water-table) in the soil. Different plant species thrive under varying combinations of these growth constraints. However in natural settings, short distance spatial variability in soil properties and subtle topographic features often complicate the definition of saline and soil hydrological conditions; additional factors may also overprint the trends identified under controlled conditions, making it difficult to define the physical settings where planting is economically viable. We investigated the establishment and growth of old man saltbush (Atriplex nummularia) in relation to variable soil-landscape conditions across an experimental site in southwestern Australia where the combination of high salinity and occasional seasonal waterlogging ruled out the growth of traditional crops and pastures. Saltbush can be critical supplemental feed in the dry season, providing essential nutrients for sheep in combination with sufficient water and dry feed (hay). We applied a range of modeling approaches including classification and regression trees and generalized linear models to statistically characterize these plant-environment relationships, and extend them spatially using full cover raster covariate datasets. Plant deaths could be consistently predicted (97% correct classification of independent dataset) using a combination of topographic variables, salinity, soil mineralogical information, and depth to the water table. Plant growth patterns were more difficult to predict, particularly after several years of grazing, however variation in plant volume was well-explained with a linear model (r2 = 0.6, P < 0.0001). All types of environmental data were required, supporting the starting hypothesis that saltland pasture success is driven by water movement in the landscape. The final selected covariates for modeling were a digital elevation model and derivatives, soil mineralogy, competitors for water (adjacent trees) and soil salinity (measured with an EM38). Our exploration of strengths and weaknesses of extrapolating simple relationships determined under controlled conditions to the field vindicates the importance of both approaches. Landholders often view the idea of the productive use of saltland with skepticism. The challenge is to use the combined datasets from glasshouse and field experiments to develop information guidelines for landholders that maximize the chances of revegetation success. Water availability, waterlogging, quality of the shallow groundwater, and secondary salinity are dominant processes that impact on agriculture in southwestern Australia. Improving our understanding of their interactions and effect on productivity will help adapt agricultural management to changing environmental conditions in the future.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Buckley, J.
1989-08-01
Species profiles are literature summaries of the taxonomy, life history, and environmental requirements of coastal fishes and aquatic invertebrates. They are designed to assist with environmental impact assessments. The rainbow smelt is an abundant forage fish for commercially and recreationally valuable fishes such as striped bass and bluefish on the East Coast and several species of salmon and trout in the Great Lakes. The rainbow smelt also supports an important sportfishery throughout most of its range. In 1976, the total smelt harvest in the coastal waters of New England was 105,000 lb. Coastal rainbow smelt are anadromous, spawning in freshwatermore » and maturing in saline water. Spawning peaks in spring. Salinities above 12 ppt were fatal to eggs. Reported fecundities are 7,000 to 44,000 eggs per female. Smelt are always found in shallow water (<6 m deep) and within 2 km of the shore. Larval and juvenile smelt along the coast feed on planktonic crustaceans. Larger juveniles and adults feed on euphausiids, amphipods, on planktonic crustaceans. Larger juveniles and adults feed on euphausiids, amphipods, polychaetes, and fish. Smelt move locally to search for optimum water temperatures. 46 refs., 2 figs., 1 tab.« less
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Grimes, B.H.; Huish, M.T.; Kerby, J.H.
1989-08-01
Species profiles are literature summaries of the taxonomy, morphology, range, life history, and environmental requirements of coastal species. They are designed to assist in environmental impact assessments. The summer flounder supports an important commercial and recreational fishery in the Mid-Atlantic and are important constituent of estuarine and continental shelf systems throughout the region. Summer flounder spawning begins in September and winter flounder spawning begins in June. Summer flounder eggs are pelagic whereas winter flounder eggs are demersal. Summer flounder larvae are more abundant in inlets, and juveniles are found in estuarine seagrass beds in salinities {>=}12 ppt. Winter flounder juvenilesmore » are abundant in shallow bays and estuaries, moving seaward in spring and summer. Growth of winter flounder and summer flounder is seasonal. There are probably three spawning populations of both species which produce a complex stock pattern. Summer flounder are tolerant of a wide range of chemical and physica faactors, but prefer {gt}10 ppt salinities. Winter flounder optimal temperature is 18.5 {degree}C. Diseases of winter flounder are more prevalent in polluted waters. Summer flounder are tolerant of sediments laden with contaminants. 64 refs., 5 figs., 2 tabs.« less
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NASA Astrophysics Data System (ADS)
Sloterdijk, Hans; Brehmer, Patrice; Sadio, Oumar; Müller, Hanno; Döring, Julian; Ekau, Werner
2017-10-01
Mangrove ecosystems have long been considered essential habitats and are commonly viewed and referred to as "nursery areas". They are highly sensitive to climate change, and environmental transformations in these ecosystems are expected. The Sine Saloum estuary is a case of a system affected by global climate change where reduced precipitation and temperature increase have resulted in an inversion of the salinity gradient. Within the estuary, the composition and structure of the larval fish community related to environmental parameters were investigated using neuston and ring trawl nets. Larval fishes were sampled at 16 stations distributed along a salinity and distance-to-the-sea gradient during four field campaigns (November 2013, February, June, and August 2014) covering an annual cycle. This is the first study documenting the spatial and temporal assemblages of fish larvae in an inverse estuary. The total of 41 taxa representing 24 families and 34 genus identified in this study was lower than that of other tropical estuaries. Clupeidae spp. was the dominant taxon, accounting for 28.9% of the total number of fish larvae caught, followed by Gerreidae spp. (21.1%), Hyporamphus picarti (18.8%), Diplodus bellottii (8.9%), Hypleurochilus langi (4.8%), Mugilidae spp. (4.4%), and Gobiidae sp.1 (3.5%). A total of 20 taxa were recorded within the upper estuary region, whereas 29 and 37 taxa were observed in the middle and lower reaches, respectively. While larval fish were captured at all sites and during all seasons, abundances and richness decreased with increasing salinity. Larval fish assemblages also showed a clear vertical structure corresponding to three distinct water strata. Salinity, water temperature, and dissolved oxygen were the variables that best explained the spatial and temporal differences in larval fish assemblages. It is difficult to forecast the future situation for this system but so far, compared to other mangrove estuarine systems, we have observed the loss of freshwater species in favour of species of marine origin. The information provided in the present study is a contribution to the knowledge of tropical biodiversity and modifications of the ichthyoplankton communities in the context of climate change and future green fund action.
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NASA Astrophysics Data System (ADS)
Pearson, Emma J.; Juggins, Steve; Farrimond, Paul
2008-08-01
We investigated relationships between sedimentary solvent-extractable long-chain alkenone (LCA) concentration and composition and environmental factors in a suite of endorheic lakes from inland Spain. LCAs were found in 14 of the 54 lakes examined, with concentrations comparable with those from previously published lacustrine settings. The composition of LCAs in our sites, however, contrast from the majority of those previously reported from lake environments; in our study the tri-unsaturated component is the most abundant component at most sites where LCAs are detected, and C 38:3 is the most abundant LCA in the majority of sites. LCA occurrence appears to be restricted to brackish-hypersaline sites and C 37 LCAs are absent above a salinity of ˜40 g L -1 suggesting a salinity control on LCA-producing organisms in these sites. Low concentrations of C 37 LCA components means U37k and U37k temperature indices are generally not applicable. Instead we find good relationships between C 38 components and (in particular mean autumn) temperature and the strongest LCA-temperature relationships are found when using a combination of all C 37 and C 38 compounds. We propose a new alkenone temperature index for lakes with elevated salinity and where the C 38 components dominate the LCA distributions. This is expressed as U3738k=0.0464×MAutAT-0.867 ( r2 = 0.80, n = 13). In this paper, we provide the first account of sedimentary LCA distributions from lakes in inland Spain, extending the range of environments within which these compounds have been found and highlighting their significance as indicators of both salinity and temperature in saline, endorheic lake environments. This has important implications for extending the potential role of LCAs as palaeoclimatic indicators in lacustrine environments.
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NASA Astrophysics Data System (ADS)
Jougnot, D.; Jimenez-Martinez, J.; Legendre, R.; Le Borgne, T.; Meheust, Y.; Linde, N.
2017-12-01
The use of time-lapse electrical resistivity tomography has been largely developed in environmental studies to remotely monitor water saturation and contaminant plumes migration. However, subsurface heterogeneities, and corresponding preferential transport paths, yield a potentially large anisotropy in the electrical properties of the subsurface. In order to study this effect, we have used a newly developed geoelectrical milli-fluidic experimental set-up with a flow cell that contains a 2D porous medium consisting of a single layer of cylindrical solid grains. We performed saline tracer tests under full and partial water saturations in that cell by jointly injecting air and aqueous solutions with different salinities. The flow cell is equipped with four electrodes to measure the bulk electrical resistivity at the cell's scale. The spatial distribution of the water/air phases and the saline solute concentration field in the water phase are captured simultaneously with a high-resolution camera by combining a fluorescent tracer with the saline solute. These data are used to compute the longitudinal and transverse effective electrical resistivity numerically from the measured spatial distributions of the fluid phases and the salinity field. This approach is validated as the computed longitudinal effective resistivities are in good agreement with the laboratory measurements. The anisotropy in electrical resistivity is then inferred from the computed longitudinal and transverse effective resistivities. We find that the spatial distribution of saline tracer, and potentially air phase, drive temporal changes in the effective resistivity through preferential paths or barriers for electrical current at the pore scale. The resulting heterogeneities in the solute concentrations lead to strong anisotropy of the effective bulk electrical resistivity, especially for partially saturated conditions. Therefore, considering the electrical resistivity as a tensor could improve our understanding of transport properties from field-scale time-lapse ERT.
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NASA Astrophysics Data System (ADS)
Dur, Gaël; Souissi, Sami
2018-01-01
Temperature and salinity are important factors shaping the habitats of estuarine ectotherms. Their respective effect varies along the life history moments of species with a complex life cycle. Estuarine species, particularly those living in the salinity gradient, are concerned by habitat changes that can reduce their fitness. Consequently, efforts to define the importance of those two environmental variables on developmental stages are required to enable forecasting estuarine species' future distributions. The present study focuses on the main component of the Seine estuary's zooplankton, i.e. the calanoid copepod Eurytemora affinis, and aims: (i) to establish the role of temperature and salinity in designing the habitat of E. affinis within the Seine estuary; and (ii) to model the habitat of three groups of E. affinis defined through the life cycle as follows: all larval instars (N1-N6), the first to fourth juvenile instars (C1-C4), and the pre-adult and adults instars (C5-Adults). For this purpose, data from intensive field studies of zooplankton sampling during 2002-2010 were used. The fine-scale data, i.e., every 10-20 min, on density and abiotic conditions (salinity, temperature) provided inputs for the computation. We established regions in salinity-temperature space where the three groups of developmental instars exhibit higher densities. The computed habitats differ between developmental groups. In general, the preferendum of salinity increases with ontogeny. The optima of temperature are rather constant between developmental stages (∼14 °C). Our model can be used to determine E. affinis functional habitat (i.e., the spatial relation with structuring factors), to carry out retrospective analysis, and to test future distributions. The present study also emphasizes the need of data from appropriate sampling strategies to conduct habitat definition.
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Martyr-Koller, R.C.; Kernkamp, H.W.J.; Van Dam, Anne A.; Mick van der Wegen,; Lucas, Lisa; Knowles, N.; Jaffe, B.; Fregoso, T.A.
2017-01-01
A linked modeling approach has been undertaken to understand the impacts of climate and infrastructure on aquatic ecology and water quality in the San Francisco Bay-Delta region. The Delft3D Flexible Mesh modeling suite is used in this effort for its 3D hydrodynamics, salinity, temperature and sediment dynamics, phytoplankton and water-quality coupling infrastructure, and linkage to a habitat suitability model. The hydrodynamic model component of the suite is D-Flow FM, a new 3D unstructured finite-volume model based on the Delft3D model. In this paper, D-Flow FM is applied to the San Francisco Bay-Delta to investigate tidal, seasonal and annual dynamics of water levels, river flows and salinity under historical environmental and infrastructural conditions. The model is driven by historical winds, tides, ocean salinity, and river flows, and includes federal, state, and local freshwater withdrawals, and regional gate and barrier operations. The model is calibrated over a 9-month period, and subsequently validated for water levels, flows, and 3D salinity dynamics over a 2 year period.Model performance was quantified using several model assessment metrics and visualized through target diagrams. These metrics indicate that the model accurately estimated water levels, flows, and salinity over wide-ranging tidal and fluvial conditions, and the model can be used to investigate detailed circulation and salinity patterns throughout the Bay-Delta. The hydrodynamics produced through this effort will be used to drive affiliated sediment, phytoplankton, and contaminant hindcast efforts and habitat suitability assessments for fish and bivalves. The modeling framework applied here will serve as a baseline to ultimately shed light on potential ecosystem change over the current century.
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Wang, Jingzhe; Abulimiti, Aerzuna; Cai, Lianghong
2018-01-01
Soil salinization is one of the most common forms of land degradation. The detection and assessment of soil salinity is critical for the prevention of environmental deterioration especially in arid and semi-arid areas. This study introduced the fractional derivative in the pretreatment of visible and near infrared (VIS–NIR) spectroscopy. The soil samples (n = 400) collected from the Ebinur Lake Wetland, Xinjiang Uyghur Autonomous Region (XUAR), China, were used as the dataset. After measuring the spectral reflectance and salinity in the laboratory, the raw spectral reflectance was preprocessed by means of the absorbance and the fractional derivative order in the range of 0.0–2.0 order with an interval of 0.1. Two different modeling methods, namely, partial least squares regression (PLSR) and random forest (RF) with preprocessed reflectance were used for quantifying soil salinity. The results showed that more spectral characteristics were refined for the spectrum reflectance treated via fractional derivative. The validation accuracies showed that RF models performed better than those of PLSR. The most effective model was established based on RF with the 1.5 order derivative of absorbance with the optimal values of R2 (0.93), RMSE (4.57 dS m−1), and RPD (2.78 ≥ 2.50). The developed RF model was stable and accurate in the application of spectral reflectance for determining the soil salinity of the Ebinur Lake wetland. The pretreatment of fractional derivative could be useful for monitoring multiple soil parameters with higher accuracy, which could effectively help to analyze the soil salinity. PMID:29736341
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Sgherri, Cristina; Pérez-López, Usue; Micaelli, Francesco; Miranda-Apodaca, Jon; Mena-Petite, Amaia; Muñoz-Rueda, Alberto; Quartacci, Mike Frank
2017-06-01
Both salt stress and high CO 2 level, besides influencing secondary metabolism, can affect oxidative status of plants mainly acting in an opposite way with salinity provoking oxidative stress and elevated CO 2 alleviating it. The aim of the present work was to study the changes in the composition of phenolic acids and flavonoids as well as in the antioxidant activity in two differently pigmented lettuce cvs (green or red leaf) when submitted to salinity (200 mM NaCl) or elevated CO 2 (700 ppm) or to their combination in order to evaluate how a future global change can affect lettuce quality. Following treatments, the red cv. always maintained higher levels of antioxidant secondary metabolites as well as antioxidant activity, proving to be more responsive to altered environmental conditions than the green one. Overall, these results suggest that the application of moderate salinity or elevated CO 2 , alone or in combination, can induce the production of some phenolics that increase the health benefits of lettuce. In particular, moderate salinity was able to induce the synthesis of the flavonoids quercetin, quercetin-3-O-glucoside, quercetin-3-O-glucuronide and quercitrin. Phenolics-enrichment as well as a higher antioxidant capacity were also observed under high CO 2 with the red lettuce accumulating cyanidin, free chlorogenic acid, conjugated caffeic and ferulic acid as well as quercetin, quercetin-3-O-glucoside, quercetin-3-O-glucuronide, luteolin-7-O-glucoside, rutin, quercitrin and kaempferol. When salinity was present in combination with elevated CO 2 , reduction in yield was prevented and a higher presence of phenolic compounds, in particular luteolin, was observed compared to salinity alone. Copyright © 2017 Elsevier Masson SAS. All rights reserved.