Science.gov

Sample records for amphipod gammarus tigrinus

  1. Natural organic matter (NOM) induces oxidative stress in freshwater amphipods Gammarus lacustris Sars and Gammarus tigrinus (Sexton).

    PubMed

    Timofeyev, Maxim A; Shatilina, Zhanna M; Kolesnichenko, Aleksey V; Bedulina, Darya S; Kolesnichenko, Viktoria V; Pflugmacher, Stephan; Steinberg, Christian E W

    2006-08-01

    Humic substances comprise the majority of natural organic matter (NOM) on Earth, including dissolved organic matter in freshwater systems. Recent studies show that these substances directly interact with aquatic organisms as chemical stressors. The aim of the present study was to investigate the mode of action of dissolved NOM on the freshwater amphipods Gammarus lacustris Sars and Gammarus tigrinus (Sexton), and in particular, to determine if NOM induces or promotes internal oxidative stress. NOM was isolated by reverse osmosis from a brown-water lake in Brandenburg State, Germany. Oxidative stress markers, such as lipid peroxidation, cell internal hydrogen peroxide concentration, as well as peroxidase, catalase and glutathione S-transferase activities, were quantified. Exposure of both amphipod species to NOM caused a significant increase in lipid peroxidation, hydrogen peroxide concentration, catalase, peroxidase and glutathione S-transferase activities. Both species showed a two-stage antioxidant response: the first stage allowed the organisms to effectively eliminate ROS and to protect cells from damage, whereas the second stage leads to H2O2 accumulation in combination with destruction of lipid structures in the cells and, finally, functional damage or even death of the organism. PMID:16542708

  2. High fecundity and predation pressure of the invasive Gammarus tigrinus cause decline of indigenous gammarids

    NASA Astrophysics Data System (ADS)

    Jänes, Holger; Kotta, Jonne; Herkül, Kristjan

    2015-11-01

    The North American amphipod Gammarus tigrinus is one of the most aggressive invaders recently expanding its distribution in the European waters. The species was detected in the north-eastern Baltic Sea in 2003 and has rapidly expanded its distribution ever since. This invasive amphipod has been notably successful in shallow, soft and mixed bottom habitats becoming one of the most abundant gammarid colonizing such environments. This study carried out two experiments: (1) an outdoor aquarium experiment to assess interspecific competition among the invasive G. tigrinus and the native Gammarus duebeni and compare their reproductive potential, and (2) an in situ meshbag experiment to determine the effect of adult G. tigrinus and native gammarids on juvenile gammarid amphipods. These demonstrated that the adult G. tigrinus had no effects on the adult G. duebeni; however, the invasive amphipod had higher reproductive potential compared to the native species such as G. duebeni. Moreover, almost all adult gammarids exerted a significant predation pressure on juvenile amphipods. Thus, the combined effect of predation on juvenile amphipods and large brood production of G. tigrinus could be plausible explanations describing increased abundance of G. tigrinus and decrease of local gammarid populations in the north-eastern Baltic Sea but plausibly in similar shallow water habitats in other seas.

  3. Embryonic transcriptome of the brackishwater amphipod Gammarus chevreuxi.

    PubMed

    Truebano, Manuela; Tills, Oliver; Spicer, John I

    2016-08-01

    Environmental change can dramatically alter the development of aquatic organisms. While the effect of such change on physiological and morphological ontogenies is becoming clearer, the molecular mechanisms underpinning them are largely unexplored. Characterizing these mechanisms is often limited by the lack of molecular resources. We have applied Illumina HiSeq sequencing to RNA isolated from different developmental stages of the brackishwater amphipod Gammarus chevreuxi. Over 52.6M paired-end reads were assembled de novo into 172,081 contigs, representing 118,812 potential genes. The assembly generated constitutes a reference embryonic transcriptome for an ecologically-important aquatic shredder species. This resource will contribute to our understanding of the mechanisms underpinning the development of physiological function through functional, comparative and quantitative expression studies. It will also allow the identification of candidate biomarkers for assessing the impact of environmental stressors in estuarine systems.

  4. Amylase Variation in the Salt Marsh Amphipod, GAMMARUS PALUSTRIS

    PubMed Central

    Borowsky, Richard; Borowsky, Betty; Milani, Haleh; Greenberg, Pietra

    1985-01-01

    There are two common alleles at the Amylase-2 locus in populations of Gammarus palustris, the salt marsh amphipod. Intensive sampling of individuals from two localities at Jamaica Bay revealed a consistent pattern of heterozygote deficiency.—Five possible sources of heterozygote deficiency were examined in this study. Four of them—selection against heterozygotes, null alleles at the locus, assortative mating for amylase genotype and inbreeding—are inconsistent with the evidence and are rejected. The fifth possibility, Wahlund effects due to genetic differentiation of the population, is tentatively accepted. Although there is no direct evidence for differentiation within this population, separate populations along the Eastern seaboard are highly differentiated in a nonclinal pattern. Furthermore, the Wahlund hypothesis is consistent with observations on differences in degree of deficiency exhibited among collections at Jamaica Bay.—Animals from this population exhibit feeding preferences correlated with genotype. Given the choice of two green algae, Enteromorpha or Ulva, the frequency of the slow allele among individuals choosing Enteromorpha was higher than among those choosing Ulva. This suggests that the animals assort themselves in the field into subpopulations with different allelic frequencies. This assortment could contribute to the maintenance of the polymorphism and to the observed heterozygote deficiency. We hypothesize that genotype influences behavior in this system through the action of enzyme on substrate, which determines the nature of the oligosaccharide pool liberated early in amylolysis. PMID:17246300

  5. Amylase Variation in the Salt Marsh Amphipod, GAMMARUS PALUSTRIS.

    PubMed

    Borowsky, R; Borowsky, B; Milani, H; Greenberg, P

    1985-10-01

    There are two common alleles at the Amylase-2 locus in populations of Gammarus palustris, the salt marsh amphipod. Intensive sampling of individuals from two localities at Jamaica Bay revealed a consistent pattern of heterozygote deficiency.-Five possible sources of heterozygote deficiency were examined in this study. Four of them-selection against heterozygotes, null alleles at the locus, assortative mating for amylase genotype and inbreeding-are inconsistent with the evidence and are rejected. The fifth possibility, Wahlund effects due to genetic differentiation of the population, is tentatively accepted. Although there is no direct evidence for differentiation within this population, separate populations along the Eastern seaboard are highly differentiated in a nonclinal pattern. Furthermore, the Wahlund hypothesis is consistent with observations on differences in degree of deficiency exhibited among collections at Jamaica Bay.-Animals from this population exhibit feeding preferences correlated with genotype. Given the choice of two green algae, Enteromorpha or Ulva, the frequency of the slow allele among individuals choosing Enteromorpha was higher than among those choosing Ulva. This suggests that the animals assort themselves in the field into subpopulations with different allelic frequencies. This assortment could contribute to the maintenance of the polymorphism and to the observed heterozygote deficiency. We hypothesize that genotype influences behavior in this system through the action of enzyme on substrate, which determines the nature of the oligosaccharide pool liberated early in amylolysis. PMID:17246300

  6. Impact of acanthocephalan parasites on aggregation behavior of amphipods (Gammarus pseudolimnaeus).

    PubMed

    Lewis, Susan E; Hodel, Ashley; Sturdy, Thomas; Todd, Rachelle; Weigl, Cassandra

    2012-10-01

    Acanthocephalan parasites can manipulate the behavior of their amphipod intermediate hosts in ways that increase the amphipod's risk of being eaten by a predator that serves as the final host for the parasite. Some asocial amphipod species have been shown to increase the likelihood of aggregation in response to chemical cues associated with predators. If such aggregation has anti-predation benefits, it might be subject to manipulation by parasites. We tested this hypothesis by comparing the preference of parasitized and unparasitized amphipods (Gammarus pseudolimnaeus) for associating with a group of unparasitized conspecifics, both in the presence and absence of chemical cues from predatory brook sticklebacks (Culaea inconstans). Amphipods with encysted parasites (Corynosoma sp.) avoided aggregating, whereas unparasitized amphipods preferred to aggregate. We also found that the risk of predation by sticklebacks faced by an individual amphipod was significantly lower when the amphipod was in a group compared to when it was alone. This suggests that the aggregation response of unparasitized amphipods is an adaptive response to escape predation. This study provides evidence for a novel parasitic manipulation of intermediate host behavior that is likely to increase transmission to the definitive host.

  7. Increased RO concentrate toxicity following application of antiscalants - acute toxicity tests with the amphipods Gammarus pulex and Gammarus roeseli.

    PubMed

    Feiner, Mona; Beggel, Sebastian; Jaeger, Nadine; Geist, Juergen

    2015-02-01

    In reverse osmosis, a frequently used technology in water desalination processes, wastewater (RO concentrate) is generated containing the retained solutes as well as so-called antiscalants (AS), i.e. chemical substances that are commonly applied to prevent membrane-blocking. In this study, a risk assessment of a possible discharge of concentrate into a small stream was conducted. The acute toxicity of two concentrates containing two different ASs and of concentrate without AS to the amphipods Gammarus pulex and Gammarus roeseli was studied. Mortality of gammarids exposed to the concentrate without AS was not different to the control, whereas concentrates including ASs caused mortality rates up to 100% at the highest test concentrations after 168 h. Resulting EC50-values were 36.2-39.4% (v/v) after 96 h and 26.6-58.0% (v/v) after 168 h. These results suggest that the ecotoxicological relevance of antiscalants is greater than currently assumed.

  8. Transcriptome of the freshwater amphipod Gammarus pulex hepatopancreas.

    PubMed

    Gismondi, E; Thomé, J P

    2016-06-01

    So far, ecotoxicological studies used biomarkers of exposure or of effects in order to investigate the impacts of contaminated areas on biota (Peakall, 1994 [6]). However, although these results are important in the ecotoxicological risk assessment, biomarkers are very specific and only provide information on the biological processes or physiological pathways targeted by the biomarkers experimenters choose to test (Monsinjon and Knigge, 2007 [5]). In recent years, proteomics have become a major tool in ecotoxicology, as they provide a global insight into the mechanism of action of pollutants without the need of hypothesis testing or any preconception on the biological processes likely impacted (Gismondi et al., 2015; Trapp et al., 2015 [7]; Truebano, 2016 [8]). However, the analysis of proteomic results is often limited due to the lack of database, especially for non-model organisms, such as Gammarus sp, commonly used as biological model in ecotoxicology (Sornom et al., 2012 [11]; Vellinger et al., 2013 [9]; Gismondi and Thomé, 2014 [1]; Lebrun et al., 2014 [3]). Here, we performed Illumina HiSeq sequencing to total RNA isolated from the hepatopancreas (i.e. detoxification tissue) of Gammarus pulex males and females coming from uncontaminated river and contaminated river (e.g. PCB, benzo(a)pyrene). Approximately 290 M paired-end reads were assembled, filtered and sorted into 39,801 contigs whose 10.878 were similar of proteins available in databases. The assembled contigs could represent a reference hepatopancreas transcriptome for G. pulex, and constitute an important resource for future investigations on the impacts of pollutants on invertebrate biota, since it would improve the understanding of the mechanisms of action involved in toxicity. In addition, the hepatopancreas transcriptome will also allow the identification of new potential biomarkers for the ecotoxicological risk assessments. Assembled contigs were deposited in the European Nucleotide Archive

  9. Transcriptome of the freshwater amphipod Gammarus pulex hepatopancreas.

    PubMed

    Gismondi, E; Thomé, J P

    2016-06-01

    So far, ecotoxicological studies used biomarkers of exposure or of effects in order to investigate the impacts of contaminated areas on biota (Peakall, 1994 [6]). However, although these results are important in the ecotoxicological risk assessment, biomarkers are very specific and only provide information on the biological processes or physiological pathways targeted by the biomarkers experimenters choose to test (Monsinjon and Knigge, 2007 [5]). In recent years, proteomics have become a major tool in ecotoxicology, as they provide a global insight into the mechanism of action of pollutants without the need of hypothesis testing or any preconception on the biological processes likely impacted (Gismondi et al., 2015; Trapp et al., 2015 [7]; Truebano, 2016 [8]). However, the analysis of proteomic results is often limited due to the lack of database, especially for non-model organisms, such as Gammarus sp, commonly used as biological model in ecotoxicology (Sornom et al., 2012 [11]; Vellinger et al., 2013 [9]; Gismondi and Thomé, 2014 [1]; Lebrun et al., 2014 [3]). Here, we performed Illumina HiSeq sequencing to total RNA isolated from the hepatopancreas (i.e. detoxification tissue) of Gammarus pulex males and females coming from uncontaminated river and contaminated river (e.g. PCB, benzo(a)pyrene). Approximately 290 M paired-end reads were assembled, filtered and sorted into 39,801 contigs whose 10.878 were similar of proteins available in databases. The assembled contigs could represent a reference hepatopancreas transcriptome for G. pulex, and constitute an important resource for future investigations on the impacts of pollutants on invertebrate biota, since it would improve the understanding of the mechanisms of action involved in toxicity. In addition, the hepatopancreas transcriptome will also allow the identification of new potential biomarkers for the ecotoxicological risk assessments. Assembled contigs were deposited in the European Nucleotide Archive

  10. Phylogeography and environmental diversification of a highly adaptable marine amphipod, Gammarus duebeni.

    PubMed

    Rock, J; Ironside, J; Potter, T; Whiteley, N M; Lunt, D H

    2007-07-01

    Genetic diversity and phylogeographic population structure in the gammarid amphipod, Gammarus duebeni, were investigated across its broad latitudinal distribution in the NE and NW Atlantic by analysis of mitochondrial DNA sequence. Gammarus duebeni has exceptional tolerance of salinity change and inhabits environments ranging from marine to freshwater. The longstanding debate on whether there are distinct marine and freshwater subspecies was assessed by sampling populations from sites characterized by different salinities. Our sequence data demonstrates that there are two major lineages, with little internal geographic structuring. Evidence is provided to suggest a pre-glacial divergence of these two clades, involving segregation between a region historically associated with the freshwater form and the majority of the marine localities on both sides of the Atlantic. A modern contact zone between the marine and freshwater forms is proposed in western Britain. PMID:17426729

  11. Seasonal drift and feeding periodicity during summer of the amphipod, Gammarus psuedolimnaeus

    USGS Publications Warehouse

    Johnson, James H.

    2014-01-01

    Downstream drift of aquatic invertebrates is an important ecological process that varies temporally. Seasonal patterns of diel drift and diel feeding periodicity during summer of the amphipod Gammarus pseudolimnaeus were examined in a small stream in central New York. Seasonal trends in drift were similar with peak drift occurring from 2000 to 0400 h. Very little drift occurred during the day. Feeding intensity of G. pseudolimnaeus was greatest from 2000 to 0400 h and was significantly greater than at 0400 to 0800 h and 0800 to 1200 h. Previous research on feeding periodicity of this species found no evidence of periods of increased food consumption. Conflicting results between this study and earlier studies may be due to sampling drifting versus non-drifting amphipods.

  12. Genotoxicity assessment in the amphipod Gammarus fossarum by use of the alkaline Comet assay.

    PubMed

    Lacaze, Emilie; Geffard, Olivier; Bony, Sylvie; Devaux, Alain

    2010-07-19

    Many xenobiotics and newly developed substances released in the aquatic environment have been found genotoxic for living organisms. There is interest in developing biomarkers of genotoxicity in different phyla and the need to increase our understanding of the impact of genotoxic insult on invertebrates, particularly on crustaceans. Freshwater invertebrates and particularly amphipods are highly relevant species ecologically. However, genotoxic responses of such species are rarely studied, whereas understanding these responses is becoming an urgent concern. The aim of this study was to develop and optimize the Comet assay in the freshwater invertebrate Gammarus fossarum by use of different cell-types: haemocytes, oocytes and spermatozoa. In a first step, the Comet assay was performed on these three cell types after exposure to the model genotoxicant methyl methanesulfonate (MMS) in vitro and in vivo. Results showed a clear dose-response relationship for all tissues, a low variability and a high sensitivity of the response, demonstrating the effectiveness of the Comet assay to detect genotoxic insult in amphipods. In a second step, to explore the potential of this technique for use in ecotoxicological studies with amphipods, these organisms were exposed to five known or suspected genotoxic compounds. The results demonstrated the possibility to use the freshwater amphipod G. fossarum in environmental genotoxicity studies with the Comet assay.

  13. Distribution of Amphipods (Gammarus nipponensis Ueno) Among Mountain Headwater Streams with Different Legacies of Debris Flow Occurrence

    EPA Science Inventory

    To understand the impacts of debris flows on the distribution of an amphipod with limited dispersal ability in the context of stream networks, we surveyed the presence of Gammarus nipponensis in 87 headwater streams with different legacies of debris flow occurrence within an 8.5-...

  14. An acanthocephalan parasite increases the salinity tolerance of the freshwater amphipod Gammarus roeseli (Crustacea: Gammaridae).

    PubMed

    Piscart, Christophe; Webb, Dennis; Beisel, Jean Nicolas

    2007-09-01

    Studies of the influence of parasites on host fitness generally conclude that parasites have a strong negative effect on their hosts. In this study, we have investigated experimentally the role of Polymorphus minutus, an acanthocephalan parasite, on the salinity tolerance of the freshwater amphipod Gammarus roeseli, one of its intermediate hosts. Unexpectedly, P. minutus-infected gammarids were more tolerant to salinity stress than uninfected ones. The mean lethal salt concentrations for 50% mortality of hosts tested were 17.3 (infected) and 9.7 g/L (uninfected). The parasitic load (one or two parasites per host) did not affect the result. The size of hosts had no significant influence on the salinity tolerance of either infected or uninfected gammarids. The mobility of all types of gammarid decreased when the salinity exceeded 9.0 g/L, but there was no significant difference between infected and uninfected gammarids. We discuss the higher salinity tolerance of infected amphipods in relation to O(2) consumption and osmoregulation. Finally, we demonstrate that the salinity tolerance is enhanced in the parasitized amphipod but without a significant change in behavior or an osmoregulatory adjustment. PMID:17487466

  15. Proteogenomics of Gammarus fossarum to document the reproductive system of amphipods.

    PubMed

    Trapp, Judith; Geffard, Olivier; Imbert, Gilles; Gaillard, Jean-Charles; Davin, Anne-Hélène; Chaumot, Arnaud; Armengaud, Jean

    2014-12-01

    Because of their ecological importance, amphipod crustacea are employed worldwide as test species in environmental risk assessment. Although proteomics allows new insights into the molecular mechanisms related to the stress response, such investigations are rare for these organisms because of the lack of comprehensive protein sequence databases. Here, we propose a proteogenomic approach for identifying specific proteins of the freshwater amphipod Gammarus fossarum, a keystone species in European freshwater ecosystems. After deep RNA sequencing, we created a comprehensive ORF database. We identified and annotated the most relevant proteins detected through a shotgun tandem mass spectrometry analysis carried out on the proteomes from three major tissues involved in the organism's reproductive function: the male and female reproductive systems, and the cephalon, where different neuroendocrine glands are present. The 1,873 mass-spectrometry-certified proteins represent the largest crustacean proteomic resource to date, with 218 proteins being lineage specific. Comparative proteomics between the male and female reproductive systems indicated key proteins with strong sexual dimorphism. Protein expression profiles during spermatogenesis at seven different stages highlighted the major gammarid proteins involved in the different facets of reproduction.

  16. Proteogenomics of Gammarus fossarum to Document the Reproductive System of Amphipods*

    PubMed Central

    Trapp, Judith; Geffard, Olivier; Imbert, Gilles; Gaillard, Jean-Charles; Davin, Anne-Hélène; Chaumot, Arnaud; Armengaud, Jean

    2014-01-01

    Because of their ecological importance, amphipod crustacea are employed worldwide as test species in environmental risk assessment. Although proteomics allows new insights into the molecular mechanisms related to the stress response, such investigations are rare for these organisms because of the lack of comprehensive protein sequence databases. Here, we propose a proteogenomic approach for identifying specific proteins of the freshwater amphipod Gammarus fossarum, a keystone species in European freshwater ecosystems. After deep RNA sequencing, we created a comprehensive ORF database. We identified and annotated the most relevant proteins detected through a shotgun tandem mass spectrometry analysis carried out on the proteomes from three major tissues involved in the organism's reproductive function: the male and female reproductive systems, and the cephalon, where different neuroendocrine glands are present. The 1,873 mass-spectrometry-certified proteins represent the largest crustacean proteomic resource to date, with 218 proteins being lineage specific. Comparative proteomics between the male and female reproductive systems indicated key proteins with strong sexual dimorphism. Protein expression profiles during spermatogenesis at seven different stages highlighted the major gammarid proteins involved in the different facets of reproduction. PMID:25293947

  17. The subtle effects of sea water acidification on the amphipod Gammarus locusta

    NASA Astrophysics Data System (ADS)

    Hauton, C.; Tyrrell, T.; Williams, J.

    2009-08-01

    We report an investigation of the effects of increases in pCO2 on the survival, growth and molecular physiology of the neritic amphipod Gammarus locusta which has a cosmopolitan distribution in estuaries. Amphipods were reared from juvenile to mature adult in laboratory microcosms at three different levels of pH in nominal range 8.1-7.6. Growth rate was estimated from weekly measures of body length. At sexual maturity the amphipods were sacrificed and assayed for changes in the expression of genes coding for a heat shock protein (hsp70 gene) and the metabolic enzyme glyceraldehyde-3-phosphate dehydrogenase (gapdh gene). The data show that the growth and survival of this species is not significantly impacted by a decrease in sea water pH of up to 0.5 units. Quantitative real-time PCR analysis indicated that there was no significant effect of growth in acidified sea water on the sustained expression of the hsp70 gene. There was a consistent and significant increase in the expression of the gapdh gene at a pH of ~7.5 which, when combined with observations from other workers, suggests that metabolic changes may occur in response to acidification. It is concluded that sensitive assays of tissue physiology and molecular biology should be routinely employed in future studies of the impacts of sea water acidification as subtle effects on the physiology and metabolism of coastal marine species may be overlooked in conventional gross "end-point" studies of organism growth or mortality.

  18. Life History and Reproductive Timing of the Endangered Illinois Cave Amphipod, Gammarus acherondytes

    NASA Astrophysics Data System (ADS)

    Venarsky, M. P.; Wilhelm, F. M.; Anderson, F. A.; Taylor, S. J.

    2005-05-01

    To aid the recovery of endangered species requires an understanding of their basic biology. Armed with such knowledge, meaningful management plans with realistic objectives can be established. We examined the life history and reproductive biology of Gammarus acherondytes, a federally endangered cave amphipod, in Reverse Stream, Monroe Co., Illinois. The population was sampled non-destructively at monthly intervals from October 2003 to February 2005. The density of gravid females peaked twice annually, (November-December and June-July) indicating major reproductive events. Gravid females also occurred at other times of the year but at low densities. Two major peaks in the density of newborn young were also observed, which lagged the density of gravid females by approximately 1-2 months. We believe this reproductive pattern is related to the influx of organic matter from mid summer storm events and leaf abscission in autumn. Young grew at a rate of 0.034 mm/day and likely reach reproductive size in one year. Adults are iteroparous and may live for several years. Our results suggest that limiting cave access in highly visited caves during peak reproduction may be a simple strategy to increase the abundance of G. acherondytes.

  19. Impact of an estrogenic sewage treatment plant effluent on life-history traits of the freshwater amphipod Gammarus pulex.

    PubMed

    Schneider, Ilona; Oehlmann, Jörg; Oetken, Matthias

    2015-01-01

    Despite efforts to upgrade sewage treatment plants (STPs) in the last decades, STPs are still a major source for the contamination of surface waters, including emerging pollutants such as pesticides, pharmaceuticals, personal care products and endocrine disrupting chemicals (EDCs). Because many of these substances are not completely removed in conventional STPs they are regularly detected in surface waters where they have the potential to affect local macroinvertebrate communities. The objective of the current work was to investigate the impact of an estrogenic wastewater effluent on the key life-history traits of the freshwater amphipod Gammarus pulex. G. pulex was exposed in artificial indoor flow-channels under constant conditions to different wastewater concentrations (0%, 33%, 66%, 100%). In parallel the estrogenic activity of wastewater samples was determined using the yeast estrogen screen (YES). Estrogenic activities in the STP effluent were up to 38.6 ng/L estradiol equivalents (EEQ). Amphipods exhibited an increasing body length with increasing wastewater concentrations. Furthermore, we observed a shift of the sex ratio in favour of females, a significantly increased fraction of brooding females and increased fecundity indices with increasing wastewater concentrations. The increased body length is likely to be attributed to the additional nutrient supply while the occurrence of EDCs in the wastewater is the probable cause for the altered sex ratio and fecundity in exposed Gammarus cohorts. PMID:25594120

  20. Metabolic activity and behavior of the invasive amphipod Dikerogammarus villosus and two common Central European gammarid species (Gammarus fossarum, Gammarus roeselii): Low metabolic rates may favor the invader.

    PubMed

    Becker, Jochen; Ortmann, Christian; Wetzel, Markus A; Koop, Jochen H E

    2016-01-01

    The Ponto-Caspian amphipod Dikerogammarus villosus is one of the most successful invaders in Central European rivers. Contrary to studies on its ecology, ecophysiological studies comparing the species' physiological traits are scarce. In this context, in particular the metabolic activity of the invasive species has rarely been considered and, moreover, the few existing studies on this species report strongly deviating results. The purpose of this study was to assess the metabolic activity and behavior of D. villosus and other common European amphipod species (Gammarus fossarum, Gammarus roeselii) in relation to temperatures covering the thermal regime of the invaded habitats. Based on direct calorimetric measurements of metabolic heat dissipation at three temperature levels (5°C, 15°C and 25°C), we found the routine metabolic rate of D. villosus to be significantly lower than that of the other studied gammarid species at the medium temperature level. The estimated resting metabolic rate indicated a similar trend. At 5°C and 25°C, both routine and resting metabolic rate did not differ between species. Compared to G. fossarum and G. roeselii, D. villosus exhibited lower locomotor activity at the low and medium temperatures (5°C and 15°C). In contrast, its locomotor activity increased at the high experimental temperature (25°C). G. fossarum and G. roeselii were apparently more active than D. villosus at all studied temperatures. We conclude that D. villosus has both physiological and behavioral adaptations that lead to a reduction in metabolic energy expenditure, which is assumed to be beneficial and might contribute to its invasive success.

  1. Cellular and stress protein responses to the UV filter 3-benzylidene camphor in the amphipod crustacean Gammarus fossarum (Koch 1835).

    PubMed

    Scheil, Volker; Triebskorn, Rita; Köhler, Heinz-R

    2008-05-01

    Chemical ultraviolet (UV) filters are used in various products and could be released into the environment, for example, via sunscreens used at swimming lakes. UV filters have been found in surface waters in the past but only a few investigations have concentrated on the effects of these substances in the environment. This study investigates the effects of a UV filter in the amphipod Gammarus fossarum at the cellular and molecular level. Stress protein (Hsp70) responses and reactions of hepatopancreatic cells and cells of gut appendices were investigated in the freshwater amphipod Gammarus fossarum after short-term exposure (4 days) to five different concentrations of the UV filter 3-benzylidene camphor (3-BC; 33 ng/L, 330 ng/L, 3.3 microg/L, 33 microg/L, 330 microg/L) and two control conditions (water and solvent ethanol). Male as well as female gammarids showed increased Hsp70 levels after exposure to low concentrations of 3-BC, with a maximum response at 3.3 microg/L, while the higher concentrations resulted in lower Hsp70 levels. This effect was most likely due to a cessation of Hsp70 synthesis following pathological impact as indicated by strong cellular responses and cellular damage obtained in epithelia of the hepatopancreas and the gut appendices after treatment with 330 microg/L 3-BC. Although environmentally relevant concentrations of 3-BC did not seem to have an adverse effect in this short-term study, higher concentrations of 3-BC are surely detrimental. It is known that chronic exposure generally requires much lower concentrations to cause harm than acute exposure. Additionally, juvenile stages may be even more sensitive than the adults tested. Therefore, on the basis of this study, 3-BC-effects in the field cannot be excluded and should be regarded possible.

  2. Habitat segregation mediates predation by the benthic fish Cottus gobio on the exotic amphipod species Gammarus roeseli

    NASA Astrophysics Data System (ADS)

    Kaldonski, Nicolas; Lagrue, Clément; Motreuil, Sébastien; Rigaud, Thierry; Bollache, Loïc

    2008-09-01

    Predation is often considered as one of the most important biotic factor determining the success of exotic species. The freshwater amphipod Gammarus roeseli has widely colonized Western Europe, where it is frequently found in sympatry with the native species ( Gammarus pulex). Previous laboratory experiments revealed that G. roeseli may have an advantage over G. pulex through differential predation by native fish (brown trout). Morphological anti-predator defences (spines) were found responsible for lower rates of predation on the invasive G. roeseli. Here, using both field surveys and laboratory experiments, we tested if a differential of predation exists with other fish predators naturally encountered by gammarids. The main predators present in our field site were nocturnal benthic feeders (mainly bullheads, Cottus gobio). Fish diet analysis showed that, compared to its global availability in the river, G. roeseli was less consumed than G. pulex. In the field, however, G. roeseli was found mainly in the aquatic vegetation whereas G. pulex was found in all habitat types. Laboratory experiments in microcosms revealed that G. roeseli was less prone to predation by C. gobio only when vegetation was present. Depending on the type of predator, the differential of predation could therefore be mediated by antipredator behaviour, and a better usage of refuges, rather than by morphological defences.

  3. Antioxidant responses in the polar marine sea-ice amphipod Gammarus wilkitzkii to natural and experimentally increased UV levels.

    PubMed

    Krapp, Rupert H; Baussant, Thierry; Bassinet, Thievery; Berge, Jørgen; Pampanin, Daniela M; Camus, Lionel

    2009-08-13

    Polar marine surface waters are characterized by high levels of dissolved oxygen, seasonally intense UV irradiance and high levels of dissolved organic carbon. Therefore, the Arctic sea-ice habitat is regarded as a strongly pro-oxidant environment, even though its significant ice cover protects the ice-associated (=sympagic) fauna from direct irradiation to a large extent. In order to investigate the level of resistance to oxyradical stress, we sampled the sympagic amphipod species Gammarus wilkitzkii during both winter and summer conditions, as well as exposed specimens to simulated levels of near-natural and elevated levels of UV irradiation. Results showed that this amphipod species possessed a much stronger antioxidant capacity during summer than during winter. Also, the experimental UV exposure showed a depletion in antioxidant defences, indicating a negative effect of UV exposure on the total oxyradical scavenging capacity. Another sympagic organism, Onisimus nanseni, was sampled during summer conditions. When compared to G. wilkitzkii, the species showed even higher antioxidant scavenging capacity. PMID:19524308

  4. Multi-level assessment of chronic toxicity of estuarine sediments with the amphipod Gammarus locusta: I. Biochemical endpoints.

    PubMed

    Neuparth, Teresa; Correia, Ana D; Costa, Filipe O; Lima, Gláucia; Costa, Maria Helena

    2005-07-01

    We report on biomarker responses conducted as part of a multi-level assessment of the chronic toxicity of estuarine sediments to the amphipod Gammarus locusta. A companion article accounts for organism and population-level effects. Five moderately contaminated sediments from two Portuguese estuaries, Sado and Tagus, were assessed. Three of them were muddy and two were sandy sediments. The objective was to assess sediments that were not acutely toxic. Three of the sediments met this criterion, the other two were diluted (50% and 75%) with clean sediment until acute toxicity was absent. Following 28-d exposures, the amphipods were analysed for whole-body metal bioaccumulation, metallothionein induction (MT), DNA strand breakage (SB) and lipid peroxidation (LP). Two of the muddy sediments did not cause chronic toxicity. These findings were consistent with responses at organism and population levels that showed higher growth rates and improvement of reproductive traits for amphipods exposed to these two sediments. Two other sediments, one muddy and one sandy, exhibited pronounced chronic toxicity, affecting SB, MT induction (in muddy sediment), survival and reproduction. Potential toxicants involved in these effects were identified. The last sandy sediment exhibited some loss of DNA integrity, however growth was also enhanced. Present results, together with the organism/population-level data, and also benthic communities information, were analysed under a weight-of-evidence approach. By providing evidence of exposure (or lack of it) to contaminants in sediments, the biomarkers here applied assisted in distinguishing toxicants' impacts in test organisms from the confounding influence of other geochemical features of the sediments. PMID:15649528

  5. Changes in antitoxic defense systems of the freshwater amphipod Gammarus pulex exposed to BDE-47 and BDE-99.

    PubMed

    Horion, Sibylle; Thomé, Jean-Pierre; Gismondi, Éric

    2015-05-01

    Polybrominated diphenyl ethers (PBDEs) are emerging pollutants widely distributed in aquatic environment. Although the bioaccumulation of this compound has been well studied, few studies have investigated their impacts on antitoxic systems of invertebrates, considering both genders. Here, we have evaluated the effects of BDE-47 and BDE-99 congeners on the antitoxic defence systems of the freshwater amphipod Gammarus pulex, and especially on the multixenobiotic resistance (MXR) activity, as well as the activities of two antitoxic enzymes, the glutathione-S-transferase (GST) and the glutathione peroxidases (GPx). Results revealed that BDE-47 and BDE-99 have inhibited the MXR activity whatever the gammarid gender, which could lead to a reduction of the pollutant elimination from the organism. In addition, a gender-biased response and a congener-biased effect on the antitoxic enzymes activities were observed. Indeed, both BDE congener exposures increased the GST activity in males, whereas in females, only BDE-99 congener modified this activity by decreasing it. On the contrary, BDE exposures did not impact the GPx activity in females, while in males BDE-99 has increased it. Results of the present study highlight that a PBDE exposure at 0.1 µg L(-1) modify antitoxic enzymes activities differently according to gender, which could lead to a change in G. pulex sensitivity on the long term. Finally, this work confirms the ecotoxicological implication of gender in the pollutant toxicity assessment, in order to evaluate impact on populations. PMID:25732806

  6. Does the presence of titanium dioxide nanoparticles reduce copper toxicity? A factorial approach with the benthic amphipod Gammarus fossarum.

    PubMed

    Rosenfeldt, Ricki R; Seitz, Frank; Zubrod, Jochen P; Feckler, Alexander; Merkel, Tobias; Lüderwald, Simon; Bundschuh, Rebecca; Schulz, Ralf; Bundschuh, Mirco

    2015-08-01

    In aquatic ecosystems, titanium dioxide nanoparticles (nano-TiO2) may adsorb co-occurring chemical stressors, such as copper (Cu). This interaction has the potential to reduce the concentration of dissolved Cu due to surface binding to the nanoparticles. The subsequent sedimentation of nano-TiO2 agglomerates may increase the exposure of benthic species towards the associated Cu. This scenario was assessed by employing the amphipod Gammarus fossarum as model species and taking advantage of a 2×2-factorial design investigating absence and presence of 2mg nano-TiO2/L and 40μg Cu/L (n=45; t=24d) in darkness, respectively. Nano-TiO2 alone did not affect mortality and leaf consumption, whereas Cu alone caused high mortality (>70%), reduced leaf consumption (25%) and feces production (30%) relative to the control. In presence of nano-TiO2, Cu-induced toxicity was largely eliminated. However, independent of Cu, nano-TiO2 decreased the gammarids' assimilation and weight. Hence, nano-TiO2 may be applicable as Cu-remediation agent, while its potential long-term effects need further attention.

  7. Impact of natural organic matter (NOM) on freshwater amphipods.

    PubMed

    Timofeyev, Maxim A; Wiegand, Claudia; Kent Burnison, B; Shatilina, Zhanna M; Pflugmacher, Stephan; Steinberg, Christian E W

    2004-02-01

    Natural organic matter (NOM) isolated from the eutrophic Sanctuary Pond (Point Pelee National Park, Canada) has an adverse impact on amphipod species (Gammarus tigrinus and Chaetogammarus ischnus from Lake Müggelsee, Germany, and Eulimnogammarus cyaneus, from Lake Baikal, Russia). Increases in amphipod mortality, changes in peroxidase activity and increases of heat shock protein (hsp70) expression were observed upon exposure to NOM. The highest resistance to the adverse impact of NOM was observed with the endemic Baikalian amphipod E. cyaneus. However, the mechanisms behind this finding remains obscure. If differences in the sensitivity of the hsp70 antibody may be excluded, different modes of action may be postulated: because the adverse impact of NOM may be caused by reactive oxygen species (ROS) and the NOM itself, the observed differences may be due to the action of ROS alone (with E. cyaneus) and a combination of both adverse modes of action (European species). PMID:14967505

  8. The Insecticide Imidacloprid Causes Mortality of the Freshwater Amphipod Gammarus pulex by Interfering with Feeding Behavior

    PubMed Central

    Nyman, Anna-Maija; Hintermeister, Anita; Schirmer, Kristin; Ashauer, Roman

    2013-01-01

    If an organism does not feed, it dies of starvation. Even though some insecticides which are used to control pests in agriculture can interfere with feeding behavior of insects and other invertebrates, the link from chemical exposure via affected feeding activity to impaired life history traits, such as survival, has not received much attention in ecotoxicology. One of these insecticides is the neonicotinoid imidacloprid, a neurotoxic substance acting specifically on the insect nervous system. We show that imidacloprid has the potential to indirectly cause lethality in aquatic invertebrate populations at low, sublethal concentrations by impairing movements and thus feeding. We investigated feeding activity, lipid content, immobility, and survival of the aquatic arthropod Gammarus pulex under exposure to imidacloprid. We performed experiments with 14 and 21 days duration, both including two treatments with two high, one day pulses of imidacloprid and one treatment with a low, constant concentration. Feeding of G. pulex as well as lipid content were significantly reduced under exposure to the low, constant imidacloprid concentration (15 µg/L). Organisms were not able to move and feed – and this caused high mortality after 14 days of constant exposure. In contrast, feeding and lipid content were not affected by repeated imidacloprid pulses. In these treatments, animals were mostly immobilized during the chemical pulses but did recover relatively fast after transfer to clean water. We also performed a starvation experiment without exposure to imidacloprid which showed that starvation alone does not explain the mortality in the constant imidacloprid exposure. Using a multiple stressor toxicokinetic-toxicodynamic modeling approach, we showed that both starvation and other toxic effects of imidacloprid play a role for determining mortality in constant exposure to the insecticide. PMID:23690941

  9. Multi-level assessment of chronic toxicity of estuarine sediments with the amphipod Gammarus locusta: II. Organism and population-level endpoints.

    PubMed

    Costa, Filipe O; Neuparth, Teresa; Correia, Ana D; Costa, Maria Helena

    2005-07-01

    This study aimed to test the performance of the amphipod Gammarus locusta (L.) in chronic sediment toxicity tests. It constitutes part of a multi-level assessment of chronic toxicity of estuarine sediments, integrating organism and population-level endpoints with biochemical markers responses. Here we account for organism and population-level effects, while biomarker responses were reported in a companion article. Five moderately contaminated sediments from Sado and Tagus estuaries were tested, comprising 3 muddy and 2 sandy sediments. These sediments either did not show acute toxicity or were diluted with control sediment as much as required to remove acute toxicity. Subsequent chronic tests consisted of 28-day exposures with survival, individual growth and reproductive traits as endpoints. Two of the muddy sediments induced higher growth rates in the amphipods, and improved reproductive traits. This was understood to be a consequence of the amount of organic matter in the sediment, which was nutritionally beneficial to the amphipods, while concurrently decreasing contaminant bioavailability. Biomarker responses did not reveal toxicant-induced stress in amphipods exposed to these sediments. One of the sandy sediments was acutely toxic at 50% dilution, but in contrast stimulated amphipod growth when diluted 75%. This was presumed to be an indication of a hormetic response. Finally the two remaining contaminated sediments showed pronounced chronic toxicity, affecting survival and reproduction. The sex ratio of survivors was highly biased towards females, and offspring production was severely impaired. The particulars of the responses of this amphipod were examined, as well as strengths versus limitations of the sediment test. This study illustrates the utility of this chronic test for toxicity assessment of contaminated estuarine sediments, with potential application all along Atlantic Europe. PMID:15649529

  10. Ecological modelling and toxicity data coupled to assess population recovery of marine amphipod Gammarus locusta: Application to disturbance by chronic exposure to aniline.

    PubMed

    de los Santos, Carmen B; Neuparth, Teresa; Torres, Tiago; Martins, Irene; Cunha, Isabel; Sheahan, Dave; McGowan, Tom; Santos, Miguel M

    2015-06-01

    A population agent-based model of marine amphipod Gammarus locusta was designed and implemented as a basis for ecological risk assessment of chemical pollutants impairing life-history traits at the individual level. We further used the model to assess the toxic effects of aniline (a priority hazardous and noxious substance, HNS) on amphipod populations using empirically-built dose-response functions derived from a chronic bioassay that we previously performed with this species. We observed a significant toxicant-induced mortality and adverse effects in reproductive performance (reduction of newborn production) in G. locusta at the individual level. Coupling the population model with the toxicological data from the chronic bioassay allowed the projection of the ecological costs associated with exposure to aniline that might occur in wild populations. Model simulations with different scenarios indicated that even low level prolonged exposure to the HNS aniline can have significant long-term impacts on G. locusta population abundance, until the impacted population returns to undisturbed levels. This approach may be a useful complement in ecotoxicological studies of chemical pollution to transfer individual-collected data to ecological-relevant levels.

  11. The Influence of the Disturbed Continuity of the River and the Invasive Species--Potamopyrgus antipodarum (Gray, 1843), Gammarus tigrinus (Sexton, 1939) on Benthos Fauna: A Case Study on Urban Area in the River Ruda (Poland).

    PubMed

    Spyra, Aneta; Kubicka, Justyna; Strzelec, Małgorzata

    2015-07-01

    The progressive degradation of aquatic ecosystems and ecohydrological role of rivers is one of the most important global environmental issues. The loss of the ability of rivers to self-purify waters due to the disturbances of river continuity cause a lack of biological life in parts of rivers or even in an entire river. The appearance of alien species in degraded aquatic environments is an increasingly common phenomenon and constitutes one of the threats to biodiversity. The aim of the study was to evaluate the possible impact of alien species Potamopyrgus antipodarum (Gray, 1843) and Gammarus tigrinus (Sexton, 1939) on native invertebrates as well as the influence of environmental factors on the occurrence benthos fauna including also alien species. The study conducted in industrial area, in the River Ruda (Poland), showed that at the sites at which the occurrence of the two alien species was observed, the density of native benthos and diversity decreased significantly. CCA analysis showed that non-native species occurred in fast water velocity and that their presence was associated with high values of conductivity, hardness, and a high chloride content. The arrival of new species from other geographical areas is one of the factors that influences the species balance in native aquatic fauna. The number of alien species in freshwater ecosystems probably will increase in the future as new aliens are moved outside of their native ranges. PMID:25868573

  12. The Influence of the Disturbed Continuity of the River and the Invasive Species--Potamopyrgus antipodarum (Gray, 1843), Gammarus tigrinus (Sexton, 1939) on Benthos Fauna: A Case Study on Urban Area in the River Ruda (Poland).

    PubMed

    Spyra, Aneta; Kubicka, Justyna; Strzelec, Małgorzata

    2015-07-01

    The progressive degradation of aquatic ecosystems and ecohydrological role of rivers is one of the most important global environmental issues. The loss of the ability of rivers to self-purify waters due to the disturbances of river continuity cause a lack of biological life in parts of rivers or even in an entire river. The appearance of alien species in degraded aquatic environments is an increasingly common phenomenon and constitutes one of the threats to biodiversity. The aim of the study was to evaluate the possible impact of alien species Potamopyrgus antipodarum (Gray, 1843) and Gammarus tigrinus (Sexton, 1939) on native invertebrates as well as the influence of environmental factors on the occurrence benthos fauna including also alien species. The study conducted in industrial area, in the River Ruda (Poland), showed that at the sites at which the occurrence of the two alien species was observed, the density of native benthos and diversity decreased significantly. CCA analysis showed that non-native species occurred in fast water velocity and that their presence was associated with high values of conductivity, hardness, and a high chloride content. The arrival of new species from other geographical areas is one of the factors that influences the species balance in native aquatic fauna. The number of alien species in freshwater ecosystems probably will increase in the future as new aliens are moved outside of their native ranges.

  13. The Influence of the Disturbed Continuity of the River and the Invasive Species— Potamopyrgus antipodarum (Gray, 1843), Gammarus tigrinus (Sexton, 1939) on Benthos Fauna: A Case Study on Urban Area in the River Ruda (Poland)

    NASA Astrophysics Data System (ADS)

    Spyra, Aneta; Kubicka, Justyna; Strzelec, Małgorzata

    2015-07-01

    The progressive degradation of aquatic ecosystems and ecohydrological role of rivers is one of the most important global environmental issues. The loss of the ability of rivers to self-purify waters due to the disturbances of river continuity cause a lack of biological life in parts of rivers or even in an entire river. The appearance of alien species in degraded aquatic environments is an increasingly common phenomenon and constitutes one of the threats to biodiversity. The aim of the study was to evaluate the possible impact of alien species Potamopyrgus antipodarum (Gray, 1843) and Gammarus tigrinus (Sexton, 1939) on native invertebrates as well as the influence of environmental factors on the occurrence benthos fauna including also alien species. The study conducted in industrial area, in the River Ruda (Poland), showed that at the sites at which the occurrence of the two alien species was observed, the density of native benthos and diversity decreased significantly. CCA analysis showed that non-native species occurred in fast water velocity and that their presence was associated with high values of conductivity, hardness, and a high chloride content. The arrival of new species from other geographical areas is one of the factors that influences the species balance in native aquatic fauna. The number of alien species in freshwater ecosystems probably will increase in the future as new aliens are moved outside of their native ranges.

  14. Effect of multiple microsporidian infections and temperature stress on the heat shock protein 70 (hsp70) response of the amphipod Gammarus pulex

    PubMed Central

    2014-01-01

    Background Increasing temperatures can be a significant stressor for aquatic organisms. Amphipods are one of the most abundant and functionally important groups of freshwater macroinvertebrates. Therefore, we conducted a laboratory experiment with Gammarus pulex, naturally infected with microsporidians. Methods In each group, 42 gammarids were exposed to 15°C and 25°C for 24 h. Sex of gammarids was determined and microsporidian infections were detected by specific PCR. To quantify stress levels of the amphipods, the 70 kDa heat shock proteins (hsp70) were analyzed by western blot. Results More males than females were detected in the randomized population sample (ratio of females/males: 0.87). No mortality occurred at 15°C, while 42.9% of gammarids died at 25°C. Sequences of three microsporidians (M1, M2, M3) were detected in this G. pulex population (99.7%-100% sequence identity to Microsporidium spp. from GenBank). Previous studies showed that M3 is vertically transmitted, while M1 and M2 are presumably horizontally transmitted. Prevalences, according to PCR, were 27.0%, 37.8% and 64.9% for Microsporidium sp. M1, M2 and M3, respectively. Cumulative prevalence was 82.4%. Multiple infections with all three microsporidians in single gammarids were detected with a prevalence of 8.1%, and bi-infections ranged between 12.2% and 25.7%. In dead gammarids, comparatively low prevalences were noted for M1 (males and females: 11.1%) and M2 (females: 11.1%; males 0%), while prevalence of M3 was higher (females: 66.7%; males: 88.9%). No significant effect of host sex on microsporidian infection was found. Significant effects of temperature and bi-infection with Microsporidium spp. M2 + M3 on hsp70 response were detected by analysis of the whole sample (15°C and 25°C group) and of M2 + M3 bi-infection and gammarid weight when analyzing the 25°C group separately. None of the parameters had a significant effect on hsp70 levels in the 15°C group. Conclusion This

  15. Toxicity effects of hazardous and noxious substances (HNS) to marine organisms: acute and chronic toxicity of p-xylene to the amphipod Gammarus locusta.

    PubMed

    Neuparth, T; Capela, R; Pereira, S P P; Moreira, S M; Santos, M M; Reis-Henriques, M A

    2014-01-01

    Despite the recent focus on hazardous and noxious substances (HNS) spills preparedness and responses, much remains to be done regarding the threat posed by HNS spills on marine biota. Among the identified priority HNS, p-xylene was selected to conduct ecotoxicological assays. The aim of this study was to assess the performance of the amphipod Gammarus locusta under acute and chronic exposure to p-xylene simulating conditions of a spill incident. In the acute exposure (96 h) the p-xylene LC50 was estimated. In the chronic bioassay (36 d), an integration of organism-level endpoints (survival, growth rate, and sex ratio) with biochemical markers indicative of oxidative stress including catalase (CAT), glutathione S-transferase (GST), and superoxide dismutase (SOD) activities and lipid peroxidation (LPO) levels was determined. The aim was to increase the xylene ecotoxicological database and better predict its impact in aquatic environments. p-Xylene induced several chronic toxicity effects in G. locusta. Significant alterations in antioxidant enzymes and lipid peroxidation levels as well as growth rate and biased sex-ratio were observed. p-Xylene significantly affected the activities of CAT, SOD, and GST in G. locusta and produced oxidative damage by increasing levels of LPO in males. Further, impacts in key ecological endpoints, that is, growth and sex ratio, were noted that might be indicative of potential effects at the population level in a spill scenario. The present data may be useful to assist relevant bodies in preparedness and response to HNS spills. PMID:25208661

  16. Effects of water temperature and pH on toxicity of terbufos, trichlorfon, 4-nitrophenol and 2,4- dinitrophenol to the amphipod Gammarus pseudolimnaeus and rainbow trout (Oncorhynchus mykiss)

    USGS Publications Warehouse

    Howe, G.E.; Marking, L.L.; Bills, T.D.; Rach, J.J.; Mayer, F.L., Jr.

    1994-01-01

    Acute toxicity tests were conducted to determine (a) the individual and interactive effects of water temperature (7, 12, 17 degree C), pH (6.5, 7.5, 8.5, 9.5), and time on the toxicity of terbufos, trichlorfon, 4- nitrophenol, and 2,4-dinitrophenol to rainbow trout (Oncorhynchus mykiss) and the amphipod Gammarus pseudolimnaeus, and (b) the individual and interactive effects of water temperature and pH on chemical bioconcentration during acute tests with rainbow trout and Gammarus exposed to terbufos, 4-nitrophenol, and 2,4-dinitrophenol. The toxicity of all four chemicals was significantly affected by pH in all tests, except for Gammarus exposed to terbufos. The toxicity of terbufos to rainbow trout and Gammarus was less at pH 7.5 than at higher or lower pH. The toxicity of both nitrophenols decreased as pH increased, whereas the toxicity of trichlorfon increased with pH. The effect of pH on trichlorfon toxicity decreased with temperature. Temperature significantly affected the toxicity of all four chemicals to both species. Toxicity increased with temperature in all tests, except for rainbow trout exposed to nitrophenols; toxicity decreased as temperature increased for rainbow trout. Chemical bioconcentration was also significantly affected by temperature and pH and was directly related to toxicity in most tests. Significant interactive effects between toxicity-modifying factors were also frequently observed. Temperature and pH effects on chemical toxicity need to be considered in chemical hazard assessment to ensure adequate protection of aquatic organisms.

  17. Effects of water temperature and pH on toxicity of terbufos, trichlorfon, 4-nitrophenol and 2,4-dinitrophenol to the amphipod Gammarus pseudolimnaeus and rainbow trout (Oncorhynchus mykiss)

    SciTech Connect

    Howe, G.E.; Marking, L.L.; Bills, T.D.; Rach, J.J. . National Fisheries Research Center); Mayer, F.L. Jr. . Environmental Research Lab.)

    1994-01-01

    Acute toxicity tests were conducted to determine (a) the individual and interactive effects of water temperature (7, 12, 17 C), pH (6.5, 7.5, 8.5, 9.5), and time on the toxicity of terbufos, trichlorfon, 4-nitrophenol, and 2,4-dinitrophenol to rainbow trout (Oncorhynchus mykiss) and the amphipod Gammarus pseudolimnaeus, and (b) the individual and interactive effects of water temperature and pH on chemical bioconcentration during acute tests with rainbow trout and Gammarus exposed to terbufos, 4-nitrophenol, and 2,4-dinitrophenol. The toxicity of all four chemicals was significantly affected by pH in all tests, except for Gammarus exposed to terbufos. The toxicity of terbufos to rainbow trout and Gammarus was less at pH 7.5 than at higher or lower pH. The toxicity of both nitrophenols decreased as pH increased, whereas the toxicity of trichlorfon increased with pH. The effect of pH on trichlorfon toxicity decreased with temperature. Temperature significantly affected the toxicity of all four chemicals to both species. Toxicity increased with temperature in all tests, except for rainbow trout exposed to nitrophenols; toxicity decreased as temperature increased for rainbow trout. Chemical bioconcentration was also significantly affected by temperature and pH and was directly related to toxicity in most tests. Significant interactive effects between toxicity-modifying factors were also frequently observed. Temperature and pH effects on chemical toxicity need to be considered in chemical hazard assessment to ensure adequate protection of aquatic organisms.

  18. Design of an electronically operated flow-through respirometer and its use to investigate the effects of copper on the respiration rate of the amphipod gammarus pulex (L.)

    SciTech Connect

    Kedwards, J.T.; Blockwell, S.J.; Tylor, E.J.; Pascoe, T.D.

    1996-12-31

    The use of oxygen consumption as a measure of metabolism has resulted in the development of many types of respirometer. These can be classified into three types. Firstly, there is the closed system in which oxygen concentration is measured at the beginning and end of the experiment and an organism`s respiratory rate calculated from the decrease in oxygen concentration and the volume of the vessel. Secondly, there is a system in which respired oxygen is replaced by oxygen from the surrounding air and the resultant change in air volume is measured gasometrically. A third approach, and the one employed in this study, utilises an open flow-through system in which water passes through a chamber containing an animal and the oxygen concentration is measured and compared to that of a reference chamber without an animal. The difference in oxygen concentration is then used to determine the respiration rate of the test animal. In open flow-through systems excretory products are washed away and water is not left stagnant as may occur in closed techniques. In addition, the open flow technique provides a constant oxygen concentration, avoids stress to animals with oxygen concentration-dependent metabolism and allows the simulation of low oxygen tension environments. Despite these obvious advantages the use of flow-through respirometers has been somewhat limited due to difficulties in calibration and complexity in construction and operation (Edwards and Learner 1960). The purpose of this investigation was to design a flow-through respirometer which is sufficiently sensitive to detect pollutant-induced respiratory changes in freshwater invertebrates and which permits automated continuous recording of the respiration of several animals maintained individually. In order to evaluate the system the effect of copper (prepared form cupric sulphate, CuSO{sub 4}.5H{sub 2}O) on the respiration of the shrimp Gammarus pulex was studied. 26 refs., 2 figs., 1 tab.

  19. Redescription of Gammarus pseudosyriacus (Karaman & Pinkster, 1977) and description of a new subspecies from southern Iran (Crustacea, Amphipoda, Gammaridae).

    PubMed

    Semsar-Kazerooni, Maryam; Zamanpoore, Mehrdad; Sadeghi, Saber

    2016-01-01

    The present study focused on redescription of Gammarus pseudosyriacus (Karaman & Pinkster, 1977) based on new materials from Zagros Mountains and describes a new subspecies of freshwater amphipod, Gammarus pseudosyriacus issatisi subsp. n., from the southern Zagros Mountains. The work is based on morphological and morphometric comparisons. This new subspecies has features similar to Gammarus pseudosyriacus. The distinct features that distinguish Gammarus pseudosyriacus issatisi subsp. n. from Gammarus pseudosyriacus are the smaller eyes, shorter body length, and shorter flagellum of antenna 1 and 2. PMID:27408590

  20. Parasite altered micro-distribution of Gammarus pulex (Crustacea: Amphipoda).

    PubMed

    MacNeil, Calum; Fielding, Nina J; Hume, Kevin D; Dick, Jaimie T A; Elwood, Robert W; Hatcher, Melanie J; Dunn, Alison M

    2003-01-01

    In a river survey, Gammarus pulex amphipods both unparasitised and parasitised with the acanthocephalan Echinorhynchus truttae were distributed similarly with respect to flow regimen, tending to be more abundant in faster, shallower, riffle patches. However, there was a higher prevalence of parasitism in faster, shallower areas than in slower, deeper areas and abundance correlated with macrophyte coverage for unparasitised but not parasitised amphipods, indicating subtle differences in habitat usage. A laboratory 'patch' simulation indicated that parasitism influenced micro-distribution. There were higher proportions of unparasitised amphipods in/under stone substrates and within weed. In contrast, there were higher proportions of parasitised amphipods in the water column and at the water surface. As the experiment progressed, unparasitised but not parasitised amphipod habitat usage shifted from those micro-habitats above the substrate and in the water column to those in/under the substrates. Experiments also demonstrated that parasitised amphipods were more active and had a greater preference for illumination. Previous studies of the effects of acanthocephalan parasitism of amphipod hosts have focussed on how drift behaviour is altered, now we show that subtle differences in micro-habitat usage could translate to greatly increased vulnerability to fish predation. We discuss how aggregation of parasitised individuals within specific habitats could promote parasite transmission. PMID:12547346

  1. PHOTOACTIVATED TOXICITY IN AMPHIPODS COLLECTED FROM POLYCYCLIC AROMATIC HYDROCARBON-CONTAMINATED SITES

    EPA Science Inventory

    The risk of photo-activated PAH toxicity in contaminated aquatic systems has not been well characterized. To better indicate this potential, amphipods (Gammarus spp.) were collected from two PAH contaminated sites (Hog Island and USX), as well as a reference site (Chipmunk Cove)...

  2. Conflict of interest between a nematode and a trematode in an amphipod host: Test of the "sabotage" hypothesis

    USGS Publications Warehouse

    Thomas, Frédéric; Fauchier, Jerome; Lafferty, Kevin D.

    2002-01-01

    Microphallus papillorobustus is a manipulative trematode that induces strong behavioural alterations in the gamaridean amphipod Gammarus insensibilis, making the amphipod more vulnerable to predation by aquatic birds (definitive hosts). Conversely, the sympatric nematodeGammarinema gammari uses Gammarus insensibilis as a habitat and a source of nutrition. We investigated the conflict of interest between these two parasite species by studying the consequences of mixed infection on amphipod behaviour associated with the trematode. In the field, some amphipods infected by the trematode did not display the altered behaviour. These normal amphipods also had more nematodes, suggesting that the nematode overpowered the manipulation of the trematode, a strategy that would prolong the nematode's life. We hypothesize that sabotage of the trematode by the nematode would be an adaptive strategy for the nematode consistent with recent speculation about co-operation and conflict in manipulative parasites. A behavioural test conducted in the laboratory from naturally infected amphipods yielded the same result. However, exposing amphipods to nematodes did not negate or decrease the manipulation exerted by the trematode. Similarly, experimental elimination of nematodes from amphipods did not permit trematodes to manipulate behaviour. These experimental data do not support the hypothesis that the negative association between nematodes and manipulation by the trematode is a result of the "sabotage" hypothesis.

  3. Amphipod densities and indices of wetland quality across the upper-Midwest, USA

    USGS Publications Warehouse

    Anteau, M.J.; Afton, A.D.

    2008-01-01

    Nutritional, behavioral, and diet data for lesser scaup (Aythya affinis [Eyton, 1838]) indicates that there has been a decrease in amphipod (Gammarus lacustris [G. O. Sars, 1863] and Hyalella azteca [Saussure, 1858]) density and wetland quality throughout the upper-Midwest, USA. Accordingly, we estimated densities of Gammarus and Hyalella in six eco-physiographic regions of Iowa, Minnesota, and North Dakota; 356 randomly selected semipermanent and permanent wetlands were sampled during springs 2004 and 2005. We also examined indices of wetland quality (e.g., turbidity, fish communities, aquatic vegetation) among regions in a random subset of these wetlands (n = 267). Gammarus and Hyalella were present in 19% and 54% of wetlands sampled, respectively. Gammarus and Hyalella densities in North Dakota were higher than those in Iowa and Minnesota. Although historical data are limited, our regional mean (1 to 12 m-3) amphipod densities (Gammarus + Hyalella) were markedly lower than any of the historical density estimates. Fish, important predators of amphipods, occurred in 31%-45% of wetlands in North Dakota, 84% of wetlands in the Red River Valley, and 74%-84% of wetlands in Iowa and Minnesota. Turbidity in wetlands of Minnesota Morainal (4.0 NTU geometric mean) and Red River Valley (6.1 NTU) regions appeared low relative to that of the rest of the upper-Midwest (13.2-17.5 NTU). We conclude that observed estimates of amphipods, fish, and turbidity are consistent with low wetland quality, which has resulted in lower food availability for various wildlife species, especially lesser scaup, which use these wetlands in the upper-Midwest. ?? 2008, The Society of Wetland Scientists.

  4. Comparison of Grazing Intensity & Diets of Native and Invasive Amphipods in Lake Erie

    NASA Astrophysics Data System (ADS)

    Duggan, J. P.; Francouer, S. N.

    2005-05-01

    Echinogammarus ischnus, an invasive amphipod originating from the Ponto Caspian Basin, was first discovered in the Detroit River in 1995 and has migrated through the lower Great Lakes displacing the native amphipod, Gammarus fasciatus. Both amphipods seek food and refuge by inhabiting substrata encrusted with zebra mussels and/or filamentous macro-algae. The filamentous green alga Cladophora, along with its epiphytic communities, are an important food source and refuge from predators and physical stresses. We examined the gut content of both amphipod species to determine their preferred food in their natural habitats, and conducted a laboratory experiment to determine each amphipod's grazing effects on algal biomass. Gut analysis was completed by taking grab samples from 4 study sites located along the western shore of Lake Erie every two weeks July through September, 2004. Amphipods were separated by species and preserved in 90% alcohol for later dissection. Algal taxa from amphipod guts were identified and enumerated using brightfield microscopy. In the lab experiment, algal biomass prior to and after two weeks of amphipod grazing was determined using ash-free dry mass and chlorophyll-a. Preliminary results indicate that E. ischnus and G. fasciatus exert approximately equal grazing pressure on the Great Lakes food web.

  5. Toxicity Studies of Polynuclear Aromatic Hydrocarbons (PAHs) on European Amphipods.

    PubMed

    Sanz-Lázaro, Carlos; Marin, Arnaldo; Borredat, Miguel

    2008-01-01

    ABSTRACT The effect of phenanthrene, fluoranthene, and pyrene in dimethyl sulfoxide on the amphipods Gammarus aequicauda, Gammarus locusta, and Corophium multisetosum was tested in a static exposure in sea water. The 48-h lethal concentration (LC(50)) of phenanthrene was 173.85 mug/L for G. aequicauda, 147.64 mug/L for G. locusta, and 215.20 mug/L for C. multisetosum. The 48-h LC(50) of fluoranthene was 49.99 mug/L for G. aequicauda, 42.71 mug/L for G. locusta, and 2.85 mug/L for C. multisetosum. The 48-h LC(50) of pyrene was 73.49 mug/L for G. aequicauda, 60.78 mug/L for G. locusta, and 25.29 mug/L for C. multisetosum. Together with their wide distribution along European coasts, the evidence of toxicity on the tested PAH compounds in these amphipods make these species appropriate candidates for evaluating oil-contaminated sediments in Europe.

  6. Gammarus spp. in aquatic ecotoxicology and water quality assessment: toward integrated multilevel tests.

    PubMed

    Kunz, Petra Y; Kienle, Cornelia; Gerhardt, Almut

    2010-01-01

    The amphipod genus Gammarus is widespread and is structurally and functionally important in epigean freshwaters of the Northern Hemisphere. Its presence is crucial, because macroinvertebrate feeding is a major rate-limiting step in the processing of stream detrius. In addition, Gammarus interacts with multiple trophic levels bu functioning as prey, predator, herbivore, detritivore, and shredder. Such a broad span of ecosystem participation underlines the importance of Gammarus to pollutants and other disturbances may render it a valuable indicator for ecosystem health. This review summarizes the vast number of studies conducted with Gammarus spp. for evaluating aquatic ecotoxicology endpoints and examines the suitability of this native invertabrate species for the assessment of stream ecosystem health in the Northern Hemisphere. Numerous papers have been published on how pollutants affect gammarind behavior (i.e., mating, predator avoidance), reproduction, development, feeding activity, population structure, as well as the consequences of pollution on host-parasite, predator-prey, or native-invasive species interactions. Some biochemical and molecular biomarkers have already been established, such as the measurement of vitellogenin-like proteins, metallothioneins, alkali-labile phosphates (in proteins), and lipogenic enzyme activities for assessing endocrine distribution and detoxification mechanisms.

  7. Invasive Macroinvertebrates in the Upper Mississippi River system: Recent Findings

    EPA Science Inventory

    Zoobenthos surveys of the great rivers of the Upper Mississippi River basin (Missouri, Upper Mississippi, and Ohio Rivers) in 2004-2006 revealed new invasions by marine and estuarine amphipods. The gammarid amphipods Echinogammarus ischnus and Gammarus tigrinus were discovered i...

  8. Influence of diet and sea ice drift on organochlorine bioaccumulation in Arctic ice-associated amphipods.

    PubMed

    Borgå, K; Poltermann, M; Polder, A; Pavlova, O; Gulliksen, B; Gabrielsen, G W; Skaare, J U

    2002-01-01

    The drifting sea ice has been suggested as important in the transport and concentration of organic matter and pollutants in the Arctic. We collected sea ice-associated amphipods in the marginal ice zone north of Svalbard and in the Fram Strait in September 1998 and 1999 to assess contaminant accumulation in ice-associated organisms. Organochlorine concentrations increased from the more herbivorous Apherusa glacialis to the more carnivorous Gammarus wilkitzkii and the more necrophagous Onisimus spp. The relative contribution of compound classes to the sum of organochlorines differed between the amphipod families, with a higher relative contribution of hexachlorocyclohexanes (HCHs) in A. glacialis. The composition of the compound classes HCHs. chlordanes and dichlorodiphenyltrichloroethanes (DDTs) was similar between the amphipod families, whereas the profiles of polychlorinated biphenyls (PCBs) differed. The occurrence of organochlorines differed spatially, with higher alpha-HCH concentrations in amphipods from the Fram Strait in comparison with amphipods collected north of Svalbard. This could be related to the sea ice drift route, since sea ice in the Fram Strait had a drift route across the central Arctic Ocean, while the sea ice north of Svalbard had a western drift route to the sampling stations. Even though marine invertebrates have direct uptake by passive diffusion of contaminants across their gills. our results imply that the species' ecology such as diet is important in the bioaccumulation process of organic pollutants. In addition, the results show that sea ice drift route influences the concentrations of organochlorine pollutants in ice-associated organisms.

  9. Identification of a putatively multixenobiotic resistance related Abcb1 transporter in amphipod species endemic to the highly pristine Lake Baikal.

    PubMed

    Pavlichenko, Vasiliy V; Protopopova, Marina V; Timofeyev, Maxim; Luckenbach, Till

    2015-04-01

    The fauna of Lake Baikal in Eastern Siberia, the largest freshwater body on Earth, is characterized by high degrees of biodiversity and endemism. Amphipods, a prominent taxon within the indigenous fauna, occur in an exceptionally high number of endemic species. Considering the specific water chemistry of Lake Baikal with extremely low levels of potentially toxic natural organic compounds, it seems conceivable that certain adaptions to adverse environmental factors are missing in endemic species, such as cellular defense mechanisms mitigating toxic effects of chemicals. The degree to which the endemic fauna is affected by the recently occurring anthropogenic water pollution of Lake Baikal may depend on the existence of such cellular defense mechanisms in those species. We here show that endemic amphipods express transcripts for Abcb1, a major component of the cellular multixenobiotic resistance (MXR) defense against toxic chemicals. Based on a partial abcb1 cDNA sequence from Gammarus lacustris, an amphipod species common across Northern Eurasia but only rarely found in Lake Baikal, respective homologous sequences were cloned from five amphipods endemic to Lake Baikal, Eulimnogammarus verrucosus, E. vittatus, E. cyaneus, E. marituji, and Gmelinoides fasciatus, confirming that abcb1 is transcribed in those species. The effects of thermal (25 °C) and chemical stress (1-2 mg L(-1) phenanthrene) in short-term exposures (up to 24 h) on transcript levels of abcb1 and heat shock protein 70 (hsp70), used as a proxy for cellular stress in the experiments, were exemplarily examined in E. verrucosus, E. cyaneus, and Gammarus lacustris. Whereas increases of abcb1 transcripts upon treatments occurred only in the Baikalian species E. verrucosus and E. cyaneus but not in Gammarus lacustris, changes of hsp70 transcript levels were seen in all three species. At least for species endemic to Lake Baikal, the data thus indicate that regulation of the identified amphipod abcb1 is

  10. Separate and combined effects of habitat-specific fish predation on the survival of invasive and native gammarids

    NASA Astrophysics Data System (ADS)

    Kotta, Jonne; Orav-Kotta, Helen; Herkül, Kristjan

    2010-10-01

    The North-American amphipod Gammarus tigrinus was observed for the first time in the northern Baltic Sea in 2003. The invasive amphipod has been particularly successful in some habitats (e.g. on pebbles) where it has become one of the most abundant gammarid species. We studied experimentally if the dominant fish Gasterosteus aculeatus preyed differentially on the exotic G. tigrinus and the native Gammarus salinus, if predation differed among habitats, and if one gammarid species facilitated predation on the other. The experiment demonstrated that (1) fish preyed more on the exotic G. tigrinus than the native G. salinus. (2) Predation did not differ among habitats. (3) Gammarus tigrinus facilitated the predation on G. salinus and this facilitation varied among habitats with significant effects on pebbles. Thus, the combined effect of habitat-specific fish predation and competition between gammarid amphipods is a possible explanation of the current range of G. tigrinus in the northern Baltic Sea. G. tigrinus seems to establish in habitats where it can significantly increase fish predation on the native gammarids.

  11. Polycyclic aromatic compound profiles from extracts of Dreissenid mussels and gammarid amphipods coexisting in Hamilton Harbor

    SciTech Connect

    Marvin, C.H.; McCarry, B.E.; Allan, L.; Bryant, D.W.

    1995-06-01

    Aggregates of dreissenid mussels were collected in Hamilton Harbour (western Lake Ontario) from a south shore site (Randle Reef) in an area characterized by coal tar-contaminated sediments, and from a site on the north shore exposed to particulates circulating in the harbour water column. Samples were separated into three components: dreissend mussels, gammarid amphipods (Gammarus fasciatus), and particulate material. The samples were freeze-dried, and extracted using ultrasonication in dichloromethane. The organic solvent extracts were subjected to an open-column alumina and Sephadex LH-20 gel column clean-up procedure, and characterized by gas chromatography-mass spectrometry (GC-MS). The chromatographic profiles of all sample extracts were dominated by polycyclic aromatic hydrocarbons (PAH). The concentrations of the individual compounds were normalized for contaminant profile comparison of the extracts of dreissenids, amphipods, and particulates associated with aggregates of dreissenid mussels. These profiles were also compared with extracts of coal tar-contaminated sediment from the Randle Reef area, and extracts of suspended particulates obtained from sediment traps. The similarities in the PAH profiles provide evidence of exposure to a common source of contaminants. These data also show that PAH associated with suspended particulates obtained from sediment traps. The similarities in the PAH profiles provide evidence of exposure to a common source of contaminants. These data also show that PAH associated with suspended particulates in Hamilton Harbour are being accumulated by dreissenid mussels and gammarid amphipods.

  12. Drastic underestimation of amphipod biodiversity in the endangered Irano-Anatolian and Caucasus biodiversity hotspots

    PubMed Central

    Katouzian, Ahmad-Reza; Sari, Alireza; Macher, Jan N.; Weiss, Martina; Saboori, Alireza; Leese, Florian; Weigand, Alexander M.

    2016-01-01

    Biodiversity hotspots are centers of biological diversity and particularly threatened by anthropogenic activities. Their true magnitude of species diversity and endemism, however, is still largely unknown as species diversity is traditionally assessed using morphological descriptions only, thereby ignoring cryptic species. This directly limits evidence-based monitoring and management strategies. Here we used molecular species delimitation methods to quantify cryptic diversity of the montane amphipods in the Irano-Anatolian and Caucasus biodiversity hotspots. Amphipods are ecosystem engineers in rivers and lakes. Species diversity was assessed by analysing two genetic markers (mitochondrial COI and nuclear 28S rDNA), compared with morphological assignments. Our results unambiguously demonstrate that species diversity and endemism is dramatically underestimated, with 42 genetically identified freshwater species in only five reported morphospecies. Over 90% of the newly recovered species cluster inside Gammarus komareki and G. lacustris; 69% of the recovered species comprise narrow range endemics. Amphipod biodiversity is drastically underestimated for the studied regions. Thus, the risk of biodiversity loss is significantly greater than currently inferred as most endangered species remain unrecognized and/or are only found locally. Integrative application of genetic assessments in monitoring programs will help to understand the true magnitude of biodiversity and accurately evaluate its threat status. PMID:26928527

  13. Drastic underestimation of amphipod biodiversity in the endangered Irano-Anatolian and Caucasus biodiversity hotspots.

    PubMed

    Katouzian, Ahmad-Reza; Sari, Alireza; Macher, Jan N; Weiss, Martina; Saboori, Alireza; Leese, Florian; Weigand, Alexander M

    2016-01-01

    Biodiversity hotspots are centers of biological diversity and particularly threatened by anthropogenic activities. Their true magnitude of species diversity and endemism, however, is still largely unknown as species diversity is traditionally assessed using morphological descriptions only, thereby ignoring cryptic species. This directly limits evidence-based monitoring and management strategies. Here we used molecular species delimitation methods to quantify cryptic diversity of the montane amphipods in the Irano-Anatolian and Caucasus biodiversity hotspots. Amphipods are ecosystem engineers in rivers and lakes. Species diversity was assessed by analysing two genetic markers (mitochondrial COI and nuclear 28S rDNA), compared with morphological assignments. Our results unambiguously demonstrate that species diversity and endemism is dramatically underestimated, with 42 genetically identified freshwater species in only five reported morphospecies. Over 90% of the newly recovered species cluster inside Gammarus komareki and G. lacustris; 69% of the recovered species comprise narrow range endemics. Amphipod biodiversity is drastically underestimated for the studied regions. Thus, the risk of biodiversity loss is significantly greater than currently inferred as most endangered species remain unrecognized and/or are only found locally. Integrative application of genetic assessments in monitoring programs will help to understand the true magnitude of biodiversity and accurately evaluate its threat status.

  14. Field evidence for non-host predator avoidance in a manipulated amphipod

    NASA Astrophysics Data System (ADS)

    Médoc, Vincent; Beisel, Jean-Nicolas

    2009-04-01

    Manipulative parasites are known to alter the spatial distribution of their intermediate hosts in a way that enables trophic transmission to definitive hosts. However, field data on the ecological implications of such changes are lacking. In particular, little is known about the spatial coexistence between infected prey and dead-end predators after a parasite-induced habitat shift. Here, we used an Amphipoda ( Gammarus roeseli)-Acanthocephala ( Polymorphus minutus) association to investigate how infection with a manipulative parasite affects the predation risk by non-hosts within the invertebrate community. First, we collected invertebrates by sampling various natural habitats and calculated the distribution amplitude of amphipods according to their infection status. Infection with P. minutus significantly reduced the habitat breadth in G. roeseli, parasitised individuals being mainly found in floating materials whereas uninfected ones were widespread throughout the sampled habitats. Second, to test if these changes also affect the risk for P. minutus to be ingested by non-hosts, we estimated the predation risk experienced by G. roeseli within the macro-invertebrate community. The habitat overlap between potential invertebrate predators and G. roeseli showed that the spatial probability of encounter was lower for P. minutus-infected amphipods than for uninfected conspecifics. For the first time, to our knowledge, a study used ecological tools to bring field evidence for the spatial avoidance of dead-end predators in a manipulated amphipod.

  15. Extracellular oxidases of the lignin-degrading fungus Panus tigrinus.

    PubMed

    Cadimaliev, D A; Revin, V V; Atykyan, N A; Samuilov, V D

    2005-06-01

    Two extracellular oxidases (laccases) were isolated from the extracellular fluid of the fungus Panus (Lentinus) tigrinus cultivated in low-nitrogen medium supplemented with birch sawdust. The enzymes were purified by successive chromatography on columns with TEAE-cellulose and DEAE-Toyopearl 650M. Both oxidases catalyze oxidation of pyrocatechol and ABTS. Moreover, oxidase 1 also catalyzes oxidation of guaiacol, o-phenylenediamine, and syringaldazine. The enzymes have identical pH (7.0) and temperature (60-65 degrees C) optimums. Absorption spectra of the oxidases differ from the spectra of typical "blue" laccases and are similar to the spectrum of yellow oxidase. PMID:16038613

  16. Evaluation of Genotoxic Potential of Waters from Two Italian Rivers in Gammarus elvirae (Amphipoda).

    PubMed

    Ronci, Lucilla; Iannilli, Valentina; De Matthaeis, Elvira; Di Donato, Giovanna; Setini, Andrea

    2015-11-01

    The aim of the present work is to evaluate the genotoxic impact of contaminants along the whole course of Ninfa-Sisto and Amaseno (Latium, Italy) rivers. The authors performed the alkaline Comet assay to assess DNA damage in the freshwater amphipod Gammarus elvirae, exposed ex situ for 24 hours and 7 days to water collected at different sites. The assay, applied on haemocytes, provides a sensitive tool to reveal effects even at low concentrations of pollutants. The results indicate significant increase of DNA damage along the course of the two rivers, compared to the unpolluted upstream sites, even if the analytes do not exceed the permissible limits. Moreover, the results show that there is not a linear correlation between the concentration of analytes and DNA damage. Based on this study's results, it would be desirable to use Comet assay, on proposed test species, as an early warning method to detect genotoxic potential of waters.

  17. Evaluation of biochemical responses in Palearctic and Lake Baikal endemic amphipod species exposed to CdCl2.

    PubMed

    Timofeyev, M A; Shatilina, Z M; Bedulina, D S; Protopopova, M V; Pavlichenko, V V; Grabelnych, O I; Kolesnichenko, A V

    2008-05-01

    This study evaluated small heat shock proteins (sHSP) (related to alpha-crystallin) and antioxidant enzymes (POD, peroxidase and CAT, catalase) as possible biomarkers for use in toxicological studies. Biochemical responses to cadmium chloride in two Lake Baikal endemic amphipods (Eulimnogammarus verrucosus, Eulimnogammarus cyaneus) and Palearctic species (Gammarus lacustris) were compared. Our findings showed that cadmium chloride toxicity directly influenced POD activity and sHSP synthesis in all amphipod species. The Baikalean endemic and the Palearctic amphipod species responded by decreasing activity of POD and they exhibited a dose-dependent activation of sHSP synthesis. All measured parameters differed among species and depended on the species' ability to resist cadmium chloride toxicity. CAT activity in the Palearctic species responded significantly to cadmium chloride exposure; however, responses were negligible for both Baikalean species. We suggest that synthesis of sHSP, together with changes in POD activity, could be used as biomarkers for further studies of amphipod species including endemics from Lake Baikal. PMID:17920682

  18. Effects of phthalate esters on the locomotor activity of the freshwater amphipod Gammarus pulex

    SciTech Connect

    Thuren, A. ); Woin, P. )

    1991-01-01

    Phthalates are of environmental concern owing to their large-scale annual production and to their ubiquitous use as additives in the manufacture of plastics. Among the phthalates, di-2-ethylhexyl phthalate (DEHP) and dibutylphthalate (DBP) are the most commonly used compounds. Phthalates are lipophilic with a relatively low water solubility and show low acute toxicity to fish and selectively toxic to cladocerans. Little is known, however, about their effects on the behavior, reproductive success or the growth of organisms. In this investigation of locomotor activity of G. pulex was studied under phthalate stress. The aim of the study was to determine the effects of phthalates on overall locomotor activity of G. pulex and the impact of long term exposure on diel activity.

  19. Mechanisms of parasite-induced sex reversal in Gammarus duebeni.

    PubMed

    Rodgers-Gray, Trevor P; Smith, Judith E; Ashcroft, Alison E; Isaac, R Elwyn; Dunn, Alison M

    2004-05-01

    The amphipod Gammarus duebeni is host to the feminising microsporidian parasite Nosema granulosis that converts males into functional females. To test the hypothesis that the parasite acts through endocrine disruption we compared the morphology of the gonad and activity of the androgenic gland, which coordinates male sexual differentiation, in infected and uninfected animals. Male gonad consisted of testis, seminal vesicle and vas deferens that was anchored to the genital papilla on segment 7. The androgenic gland was associated with the distal end of the vas deferens. In female and intersex animals the bi-lobed ovary opened into the oviduct at segment 5, vestigial vas deferens and vestigial androgenic gland were retained. The majority of parasitised individuals (38/39) were either phenotypic females or intersexes with fully developed ovaries and an undifferentiated androgenic gland. Our data suggest that the parasite prevents differentiation of the androgenic gland. In further support of this hypothesis, mass spectrometry of a single androgenic gland from males revealed a dominant molecular ion with a mass/charge ratio of 4818.4+H, corresponding to a peptide of androgenic gland hormone from Armadillidium vulgare. In contrast the vestigial androgenic gland from parasitised and unparasitised females showed only low intensity peaks. Our observations demonstrate that the parasite manipulates host sex by preventing androgenic gland differentiation, androgenic gland hormone production and consequently male differentiation. This is in agreement with observations of A. vulgare with inherited Wolbachia infection, suggesting that phylogenetically distant feminisers manipulate hosts through a common mechanism. The high frequency of infection in intersexes (89.3%) suggests that this phenotype results from incomplete feminisation by the parasite. PMID:15111096

  20. Conflict between parasites with different transmission strategies infecting an amphipod host.

    PubMed

    Haine, Eleanor R; Boucansaud, Karelle; Rigaud, Thierry

    2005-12-01

    Competition between parasites within a host can influence the evolution of parasite virulence and host resistance, but few studies examine the effects of unrelated parasites with conflicting transmission strategies infecting the same host. Vertically transmitted (VT) parasites, transmitted from mother to offspring, are in conflict with virulent, horizontally transmitted (HT) parasites, because healthy hosts are necessary to maximize VT parasite fitness. Resolution of the conflict between these parasites should lead to the evolution of one of two strategies: avoidance, or sabotage of HT parasite virulence by the VT parasite. We investigated two co-infecting parasites in the amphipod host, Gammarus roeseli: VT microsporidia have little effect on host fitness, but acanthocephala modify host behaviour, increasing the probability that the amphipod is predated by the acanthocephalan's definitive host. We found evidence for sabotage: the behavioural manipulation induced by the Acanthocephala Polymorphus minutus was weaker in hosts also infected by the microsporidia Dictyocoela sp. (roeselum) compared to hosts infected by P. minutus alone. Such conflicts may explain a significant portion of the variation generally observed in behavioural measures, and since VT parasites are ubiquitous in invertebrates, often passing undetected, conflict via transmission may be of great importance in the study of host-parasite relationships.

  1. Thermal Preference Ranges Correlate with Stable Signals of Universal Stress Markers in Lake Baikal Endemic and Holarctic Amphipods

    PubMed Central

    Axenov-Gribanov, Denis; Bedulina, Daria; Shatilina, Zhanna; Jakob, Lena; Vereshchagina, Kseniya; Lubyaga, Yulia; Gurkov, Anton; Shchapova, Ekaterina; Luckenbach, Till; Lucassen, Magnus; Sartoris, Franz Josef; Pörtner, Hans-Otto; Timofeyev, Maxim

    2016-01-01

    Temperature is the most pervasive abiotic environmental factor for aquatic organisms. Fluctuations in temperature range lead to changes in metabolic performance. Here, we aimed to identify whether surpassing the thermal preference zones is correlated with shifts in universal cellular stress markers of protein integrity, responses to oxidative stress and lactate content, as indicators of anaerobic metabolism. Exposure of the Lake Baikal endemic amphipod species Eulimnogammarus verrucosus (Gerstfeldt, 1858), Ommatogammarus flavus (Dybowski, 1874) and of the Holarctic amphipod Gammarus lacustris Sars 1863 (Amphipoda, Crustacea) to increasing temperatures resulted in elevated heat shock protein 70 (Hsp70) and lactate content, elevated antioxidant enzyme activities (i.e., catalase and peroxidase), and reduced lactate dehydrogenase and glutathione S-transferase activities. Thus, the zone of stability (absence of any significant changes) of the studied molecular and biochemical markers correlated with the behaviorally preferred temperatures. We conclude that the thermal behavioral responses of the studied amphipods are directly related to metabolic processes at the cellular level. Thus, the determined thermal ranges may possibly correspond to the thermal optima. This relationship between species-specific behavioral reactions and stress response metabolism may have significant ecological consequences that result in a thermal zone-specific distribution (i.e., depths, feed spectrum, etc.) of species. As a consequence, by separating species with different temperature preferences, interspecific competition is reduced, which, in turn, increases a species’ Darwinian fitness in its environment. PMID:27706227

  2. Fish and land use influence Gammarus lacustris and Hyalella azteca (Amphipoda) densities in large wetlands across the upper Midwest

    USGS Publications Warehouse

    Anteau, M.J.; Afton, A.D.; Anteau, A.C.E.; Moser, E.B.

    2010-01-01

    Gammarus lacustris and Hyalella azteca (hereafter G. lacustris and H. azteca, respectively) are important components of secondary production in wetlands and shallow lakes of the upper Midwest, USA. Within the past 50 years, amphipod densities have decreased while occurrences of fish and intensity of agricultural land use have increased markedly across this landscape. We investigated influences of fish, sedimentation, and submerged aquatic vegetation (SAV) on densities of G. lacustris and H. azteca in semipermanent and permanent wetlands and shallow lakes (n = 283) throughout seven eco-physiographic regions of Iowa, Minnesota, and North Dakota during 2004-2005. G. lacustris and H. azteca densities were positively correlated with densities of SAV (P<0.001 and P<0.001, respectively). Both species were negatively correlated with densities of large fish (non-Cyprinidae; P = 0.01 and P = 0.013, respectively) and with high densities of fathead minnows (Pimephales promelas; P<0.001 and P = 0.033, respectively). H. azteca densities also were negatively correlated with densities of small fish (e.g., other minnows [Cyprinidae] and sticklebacks [Gasterosteidae]; P = 0.048) and common carp (Cyprinus spp.; P = 0.022). G. lacustris densities were negatively correlated with high levels of suspended solids (an index for sedimentation; P<0.001). H. azteca densities were positively correlated with the width of upland-vegetation buffers (P = 0.004). Our results indicate that sedimentation and fish reduce amphipod densities and may contribute to the current low densities of amphipods in the upper Midwest. Thus, removing/excluding fish, and providing a thick buffer of upland vegetation around wetlands may help restore amphipod densities and wetland and water quality within this landscape. ?? Springer Science+Business Media B.V. (outside the USA) 2011.

  3. Fish and land use influence Gammarus lacustris and Hyalella azteca (Amphipoda) densities in large wetlands across the upper Midwest

    USGS Publications Warehouse

    Anteau, Michael J.; Afton, Alan D.; Anteau, Andrea C.E.; Moser, E. Barry

    2011-01-01

    Gammarus lacustrisK/i> and Ki>Hyalella azteca (hereafter G. lacustris and H. azteca, respectively) are important components of secondary production in wetlands and shallow lakes of the upper Midwest, USA. Within the past 50 years, amphipod densities have decreased while occurrences of fish and intensity of agricultural land use have increased markedly across this landscape. We investigated influences of fish, sedimentation, and submerged aquatic vegetation (SAV) on densities of G. lacustris and H. azteca in semipermanent and permanent wetlands and shallow lakes (n = 283) throughout seven eco-physiographic regions of Iowa, Minnesota, and North Dakota during 2004–2005. G. lacustris and H. azteca densities were positively correlated with densities of SAV (P P P = 0.01 and P = 0.013, respectively) and with high densities of fathead minnows (Pimephales promelas; P P = 0.033, respectively). H. azteca densities also were negatively correlated with densities of small fish (e.g., other minnows [Cyprinidae] and sticklebacks [Gasterosteidae]; P = 0.048) and common carp (Cyprinus spp.; P = 0.022). G. lacustris densities were negatively correlated with high levels of suspended solids (an index for sedimentation; P H. azteca densities were positively correlated with the width of upland-vegetation buffers (P = 0.004). Our results indicate that sedimentation and fish reduce amphipod densities and may contribute to the current low densities of amphipods in the upper Midwest. Thus, removing/excluding fish, and providing a thick buffer of upland vegetation around wetlands may help restore amphipod densities and wetland and water quality within this landscape.

  4. Size at the onset of maturity (SOM) revealed in length-weight relationships of brackish amphipods and isopods: An information theory approach

    NASA Astrophysics Data System (ADS)

    Longo, Emanuela; Mancinelli, Giorgio

    2014-01-01

    In amphipods and other small-sized crustaceans, allometric relationships are conventionally analysed by fitting the standard model Y = a·Xb (X and Y are, e.g., body length and weight, respectively) whose scaling exponent b is assumed to be constant. However, breakpoints in allometric relationships have long been documented in large-sized crustaceans, ultimately determined by ontogenetic, abrupt variations in the value of b. Here, the existence of breakpoints in length-weight relationships was investigated in four amphipod (i.e., Gammarus aequicauda, Gammarus insensibilis, Microdeutopus gryllotalpa, and Dexamine spinosa) and three isopod species (i.e., Lekanesphaera hookeri, Sphaeroma serratum, and Cymodoce truncata) from three Mediterranean lagoons. The power of two candidate linear models fitted to log10-transformed data - a simple model assuming a constant exponent b and a segmented model assuming b to vary after a breakpoint - was compared using a parsimonious selection strategy based on the Akaike information criterion. The segmented model with a breakpoint provided the most accurate fitting of length-weight data in the majority of the species analysed; non-conclusive results were obtained only for D. spinosa and C. truncata, of which a limited number of specimens was examined. Model parameters were consistent for amphipod and isopod species collected across the three different habitats; the generality of the results was further supported by a literature search confirming that the identified breakpoints corresponded with ontogenetic discontinuities related with sexual maturation in all the species investigated. In this study, segmented regression models were revealed to provide a statistically accurate and biologically meaningful description of length-weight relationships of common amphipod and isopod species. The methodological limitations of the approach are considered, while the practical implications for secondary production estimates are discussed.

  5. Antioxidant enzyme activity in endemic Baikalean versus Palaearctic amphipods: tagma- and size-related changes.

    PubMed

    Timofeyev, M A

    2006-03-01

    The activities of key antioxidant enzymes in two endemic Baikalean amphipod species: Pallasea cancelloides (Gerstf), Eulimnogammarus verrucosus (Gerstf) and the widely distributed Palearctic species Gammarus lacustris (Sars) were studied. This work was done to prove or disprove the hypothesis that Baikalean endemics have specifics in antioxidants system different from Palearctic species. The activities of antioxidant enzymes peroxidase, catalase and glutathione-S-transferase were measured in different sections (tagmata) of the amphipods' bodies as well as in different size groups. Well expressed tagma-related differences in peroxidase activity as well as smaller differences in catalase activity were shown in all studied species. There were no measured differences in glutathione-S-transferase activity among body sections. The existence of size-related changes in some antioxidant enzymes and the difference in such changes between Baikalean and Palearctic amphipods were noted. A significant increase in peroxidase activity with the size was found in both Baikalean species while a significant decrease in peroxidase activity was observed in the Palearctic G. lacustris. In Baikalean P. cancelloides, a significant decrease of catalase activity with the increase in age of crustaceans was noted, while in E. verrucosus no such relationship was found. In the Palearctic G. lacustris, a significant increase in catalase activity with the increase in size was noted. All species are shown to have no size-related differences in glutathione-S-transferase activity. The differences between species as well as between both different tagmata and size-classes within a particular species were estimated. It was assumed that the estimated differences in enzymes activity most likely depend on interspecific variation, rather than on conditional specifics in Lake Baikal. PMID:16460977

  6. Potential effects of recurrent low oxygen conditions on the Illinois Cave amphipod

    USGS Publications Warehouse

    Panno, S.V.; Hackley, Keith C.; Kelly, W.R.; Hwang, H.-H.; Wilhelm, F.M.; Taylor, S.J.; Stiff, B.J.

    2006-01-01

    The caves of Illinois' sinkhole plain are the sole habitat of the Illinois Cave amphipod (Gammarus acherondytes), a federally endangered species. The sinkhole plain is a hydrologically-connected sequence of karstified limestone that constitutes an extensive karst aquifer which serves as an important source of potable water for area residents. During this investigation, we examined the ground-water quality in caves within two ground-water basins: 1) Illinois Caverns, where the amphipod is now present after previously reported to have been extirpated from the lower reaches, and 2) Stemler Cave, where the amphipod is reported to have been extirpated. The chemical composition of cave streams in Illinois Caverns and Stemler Cave were compared to determine which parameters, if any, could have contributed to the loss of G. acherondytes from Stemler Cave. Stream water in Stemler Cave contained higher concentrations of organic carbon, potassium, silica, chloride, fluoride, sulfate, iron and manganese than Illinois Caverns. Perhaps most importantly, dissolved oxygen (DO) concentrations in Stemler Cave were, during periods of low flow, substantially lower than in Illinois Caverns. Based on land use, there are probably at least eight times more private septic systems in the Stemler Cave ground-water basin than in the Illinois Caverns ground-water basin. Low DO concentrations were likely the result of microbial breakdown of soil organic matter and wastewater treatment system effluent, and the oxidation of pyrite in bedrock. The near-hypoxic DO in Stemler Cave that occurred during low-flow conditions, and, we speculate, a limited range of G. acherondytes within the Stemler Cave ground-water basin due to a metabolic advantage of the stygophilic aquatic invertebrates over the stygobitic G. acherodytes, resulted in the apparent loss of G. acherondytes from Stemler Cave.

  7. Population response to ozone application in wastewater: an on-site microcosm study with Gammarus fossarum (Crustacea: Amphipoda).

    PubMed

    Bundschuh, Mirco; Schulz, Ralf

    2011-03-01

    We assessed possible ecotoxicological implications of ozone application to secondary treated wastewater from a municipal wastewater treatment plant on Gammarus fossarum, an aquatic leaf shredding amphipod. Our 10-week study exposed G. fossarum populations to ozone-treated, non-ozone treated wastewater, or tap water in replicated outdoor flow-through stream microcosms. Feeding activity, an indicator for organic matter decomposition, of amphipod populations exposed to ozone treated wastewater was significantly higher compared to those exposed to non-ozone treated wastewater (repeated measure ANOVA, p = 0.0002, df = 44). Also the population size was at the end of the experiment with approximately 150% significantly (t-test, p = 0.0059, n = 4) increased in ozone treated wastewater compared to non-ozone treated wastewater. Additionally, chlorophyll-a concentration, an indicator for algal biomass, was significantly higher in ozone treated wastewater (repeated measure ANOVA, p = 0.0404, df = 65). Thus, from an ecotoxicological viewpoint, we conclude that ozonation may improve wastewater quality, which should translate into positive ecological outcomes in the receiving waters. However, because ozonation also can cause toxic transformation products, the process may best be considered on a case-by-case basis. PMID:21267649

  8. An integrated study on Gammarus elvirae (Crustacea, Amphipoda): perspectives for toxicology of arsenic-contaminated freshwater.

    PubMed

    Davolos, Domenico; Chimenti, Claudio; Ronci, Lucilla; Setini, Andrea; Iannilli, Valentina; Pietrangeli, Biancamaria; De Matthaeis, Elvira

    2015-10-01

    The Italian region Latium is characterized by extensive quaternary volcanic systems that contribute greatly to arsenic (As) contamination of freshwater, including drinking water supplies. However, knowledge of the possible toxic effects in these aquatic environments is, despite being highly relevant to public health, still limited. In this paper, we approach this issue using Gammarus elvirae, an amphipod species that inhabits rivers and streams in central Italy, including Latium. We explored the possibility of using G. elvirae in the toxicology of freshwater by addressing the most relevant issues. First, we tested the usefulness of hemocytes from G. elvirae in determining non-specific DNA damage by means of the Comet assay after exposure (24 h and 7 days) to different river water samples in Latium; second, we provided an interpretative overview of the usefulness of hepatopancreatic epithelial cells of G. elvirae as a means of assessing toxicity after long-term exposure to As and other pollutants; third, the LC (50-240 h) value for G. elvirae was estimated for arsenate, which is usually the dominant arsenic species in surface waters. Our study sheds light on G. elvirae at different levels, providing a background for future toxicological research of freshwater.

  9. An integrated study on Gammarus elvirae (Crustacea, Amphipoda): perspectives for toxicology of arsenic-contaminated freshwater.

    PubMed

    Davolos, Domenico; Chimenti, Claudio; Ronci, Lucilla; Setini, Andrea; Iannilli, Valentina; Pietrangeli, Biancamaria; De Matthaeis, Elvira

    2015-10-01

    The Italian region Latium is characterized by extensive quaternary volcanic systems that contribute greatly to arsenic (As) contamination of freshwater, including drinking water supplies. However, knowledge of the possible toxic effects in these aquatic environments is, despite being highly relevant to public health, still limited. In this paper, we approach this issue using Gammarus elvirae, an amphipod species that inhabits rivers and streams in central Italy, including Latium. We explored the possibility of using G. elvirae in the toxicology of freshwater by addressing the most relevant issues. First, we tested the usefulness of hemocytes from G. elvirae in determining non-specific DNA damage by means of the Comet assay after exposure (24 h and 7 days) to different river water samples in Latium; second, we provided an interpretative overview of the usefulness of hepatopancreatic epithelial cells of G. elvirae as a means of assessing toxicity after long-term exposure to As and other pollutants; third, the LC (50-240 h) value for G. elvirae was estimated for arsenate, which is usually the dominant arsenic species in surface waters. Our study sheds light on G. elvirae at different levels, providing a background for future toxicological research of freshwater. PMID:26013740

  10. Quantifying diet-borne metal uptake in Gammarus pulex using stable isotope tracers.

    PubMed

    Pellet, Bastien; Ayrault, Sophie; Tusseau-Vuillemin, Marie-Hélène; Gourlay-Francé, Catherine

    2014-12-01

    Gammarids are aquatic amphipods widely used for water quality monitoring. To investigate the copper and cadmium diet-borne metal uptake in Gammarus pulex, we adapted the pulse-chase stable isotopes-based approach to determine the food ingestion rate (IR), the gut retention time (GRT) and the metal assimilation efficiencies (AE). G. pulex were fed with (65)Cu-, (106)Cd-, and (53)Cr-labeled alder leaves for 7.5h and then with unlabeled leaves for 5d. The metal stable isotope contents in the gammarids, leaves, filtered water and periodically collected feces were determined. Chromium was poorly assimilated by the gammarids; thus, Cr was used as an unassimilated tracer. The first tracer defecation occurred before the first feces harvest, indicating a gut passage time of less than 9h. A 24-h GRT and a 0.69gg(-1)d(-1) IR were estimated. The Cd AE value was estimated as 5-47%, depending on the assimilation determination method applied. The Cu AE value could not be evaluated regardless of the determination method used, most likely because of the rapid Cu regulation in gammarids in addition to analytical uncertainties when determining the Cu content in leaves. Application of the Cd AE value in the framework of the biodynamic bioaccumulation model shows that the diet-borne uptake of Cd significantly contributes (66-95%) to the metal bioaccumulation in G. pulex fed with alder leaves.

  11. Complete mitochondrial genome of the Antarctic amphipod Gondogeneia antarctica (Crustacea, amphipod).

    PubMed

    Shin, Seung Chul; Cho, Jin; Lee, Jong Kyu; Ahn, Do Hwan; Lee, Hyoungseok; Park, Hyun

    2012-02-01

    The complete sequence of the mitochondrial genome of the Antarctic amphipod Gondogeneia antarctica was determined to be 18,424 bp in length, and to contain 13 protein-coding genes (PCGs), 22 tRNA genes, and large (rrnL) and small (rrnS) rRNA genes. Its total A+T content is 70.1%. The G. antarctica mitogenome is the largest known among those of crustaceans, due to the existence of two relatively large intergenic non-coding sequences. The PCG arrangement of G. antarctica is identical to that of the ancestral pancrustacean ground pattern, although the tRNA arrangement differs somewhat. The complete mitogenome sequences of 68 species of pancrustacea have been added to the NCBI database, only 4 of which represent complete mitogenome sequences from amphipods. This is the first report of a mitogenome sequence of an Antarctic amphipod, and provides insights into the evolution of crustacean mitochondrial genomes, particularly in amphipods.

  12. Pathologies of Oligacanthorhynchus pardalis (Acanthocephala, Oligacanthorhynchidae) in Leopardus tigrinus (Carnivora, Felidae) in Southern Brazil.

    PubMed

    Gallas, Moisés; da Silveira, Eliane Fraga; da Silvera, Eliane Fraga

    2012-01-01

    In Brazil, Oligacanthorhynchus pardalis (Westrumb, 1821) Schmidt, 1972 has been observed in five species of wild felines. In the present study, five roadkilled oncillas (Leopardus tigrinus Schreber, 1775) were collected in the State of Rio Grande do Sul, Brazil. Chronic lesions caused by O. pardalis were observed in the small intestine of one of the specimens. Histological examination identified a well-defined leukocyte infiltration and an area of collagenous fibrosis. Only males parasites (n = 5) were found, with a prevalence of 20%. The life cycle of Oligacanthorhynchus species is poorly known, although arthropods may be their intermediate hosts. The low prevalence encountered may be related to the small number of hosts examined, and the reduced ingestion of arthropods infected by larvae of O. pardalis. This is the first report of O. pardalis parasitizing L. tigrinus in the Brazilian state of Rio Grande do Sul.

  13. Optimal conditions for the fruit body production of natural occurring strains of Lentinus tigrinus.

    PubMed

    Lechner, Bernardo E; Albertó, Edgardo

    2007-07-01

    Lentinus tigrinus is a species with a fleshy pileus, strong odor and agreeable taste. In order to determine the optimal conditions for the production of this species, three substrates based on Salix sp. sawdust, wheat straw and supplements were tested in 500g dry weight bags at two different fruiting temperatures. Naturally occurring strains of this species were incubated at 30 degrees C. Primordium initiation could be observed 11-16 days after induction conditions began. This species produced highest yields with biological efficiency (BE) of 62% with supplemented sawdust at 25 degrees C. When bags were reduced to 100g dry weight, spawning run time was reduced from 28 to 30 to 10 to 14 days and BE increased more than 100%. L. tigrinus is a promising species with possibilities for commercial production. PMID:17239586

  14. [The effect of copper ions on the production of laccase by the fungus Lentinus (Panus) tigrinus].

    PubMed

    Shutova, V V; Revin, V V; Makushina, Iu A

    2008-01-01

    The basidiomycete Lentinus tigrinus was cultured in media containing copper ions added at different growth stages. Copper ions at increased concentrations decelerated of the fungal biomass accumulation. The later Cu2+ ions were added, the better the fungal mycelium developed, and the toxic effect of Cu2+ was less pronounced. The maximum laccase activity (47 U/ml) was observed in the presence of 1.5-2.0 mM Cu2+ added on day 4 of cultivation. PMID:19145976

  15. Waterborne toxicity and diet-related effects of fungicides in the key leaf shredder Gammarus fossarum (Crustacea: Amphipoda).

    PubMed

    Zubrod, J P; Englert, D; Wolfram, J; Wallace, D; Schnetzer, N; Baudy, P; Konschak, M; Schulz, R; Bundschuh, M

    2015-12-01

    Animals involved in leaf litter breakdown (i.e., shredders) play a central role in detritus-based stream food webs, while their fitness and functioning can be impaired by anthropogenic stressors. Particularly fungicides can affect shredders via both waterborne exposure and their diet, namely due to co-ingestion of adsorbed fungicides and shifts in the leaf-associated fungal community, on which shredders' nutrition heavily relies. To understand the relevance of these effect pathways, we used a full 2×2-factorial test design: the leaf material serving as food was microbially colonized for 12 days either in a fungicide-free control or exposed to a mixture of five current-use fungicides (sum concentration of 62.5μg/L). Similarly, the amphipod shredder Gammarus fossarum was subjected to the same treatments but for 24 days. Waterborne exposure reduced leaf consumption by ∼20%, which did not fully explain the reduction in feces production (∼30%), indicating an enhanced utilization of food to compensate for detoxification mechanisms. This may also explain the reduced feces production (∼10%) of gammarids feeding on fungicide-exposed leaves. The reduction may, however, also be caused by a decreased nutritious quality of the leaves indicated by a reduced species richness (∼40%) of leaf-associated fungi. However, compensation for these effects by Gammarus was seemingly incomplete, since both waterborne exposure and the consumption of the fungicide-affected diet drastically reduced gammarid growth (∼110% and ∼40%, respectively). Our results thus indicate that fungicide mixtures have the potential for detrimental implications in aquatic ecosystem functioning by affecting shredders via both effect pathways. PMID:26520670

  16. [The role of laccase and peroxidase of Lentinus (Panus) tigrinus fungus in biodegradation of high phenol concentrations in liquid medium].

    PubMed

    Kadimaliev, D A; Revin, V V; Atykian, N A; Nadezhina, O S; Parshin, A A

    2011-01-01

    The possibility of the usage of Lentinus tigrinus fungus strain VKM F-3616D for biodegradation of high (up to 5%) phenol concentrations in liquid medium and the involvement of laccase and peroxidase in this process have been studied. L. tigrinus fungus was demonstrated to effectively digrade phenol with easy biomass separation from the liquid. Decrease in phenol concentration was accompanied by increased secretion level and laccase activity at the preliminary stages of biodegradation, while that of peroxidase was at the latest stages of biodegradation. These enzyme secretions in distinct ratios and consequences are necessary for effective phenol biodegradation. An effective approach for phenol concentration decrease in the waste water of smoking shops in meat-processing factories using L. tigrinus fungus was described. PMID:21442922

  17. [Antioxidant Effect on the Growth And Formation of Lipids in the Fungus Lentinus tigrinus Growing on Medium with Lignosulfonate].

    PubMed

    Ivashechkin, A A; Sergeeva, J E; Lunin, V V; Mysyakina, J S; Feofilova, E P

    2015-01-01

    The addition of an antioxidant (2-ethyl-6-methyl-3-hydroxypyridine hydrochloride) to a culture of the fungus Lentinus tigrinus growing on a medium with lignosulfonate inhibited growth and changed the composition of cell phospholipids. The ratio of lipid messengers also changed, the phosphatidic acid level decreased, and the content of phosphatidylinositol dramatically increased. The substitution of lignosulfonate with glucose and the addition of an antioxidant increased the biomass yield of L. tigrinus, as well as that of another fungus, Cunninghamella japonica, which was incapable of biodegrading the biopolymer. The obtained results indicate the specificity of growth processes in the presence of lignosulfonate and confirm the role of free radical oxidation reactions in the biodegradation of this biopolymer by L. tigrinus. PMID:26204778

  18. Potential exposure routes and accumulation kinetics for poly- and perfluorinated alkyl compounds for a freshwater amphipod: Gammarus spp. (Crustacea).

    PubMed

    Bertin, Delphine; Labadie, Pierre; Ferrari, Benoît J D; Sapin, Alexandre; Garric, Jeanne; Geffard, Olivier; Budzinski, Hélène; Babut, Marc

    2016-07-01

    Gammarids were exposed to sediments from a deposition site located on the Rhône River (France) downstream of a fluoropolymer manufacturing plant. Gammarids accumulated to various extents four long-chain perfluoroalkyl carboxylic acids (PFCAs) from C9 to C13, one sulfonate, perfluorooctane sulfonate (PFOS) and three of its precursors (the perflurooctane sulfonamide (FOSA), the N-methyl perfluorooctane sulfonamidoacetic acid (MeFOSAA), the N-ethyl perfluorooctane sulfonamidoacetic acid (EtFOSAA) and the 6:2 fluorotelomer sulfonic acid (6:2 FTSA). Whatever the compound, the steady state was not achieved after a 3-week exposure; elimination was almost complete after a 3-week depuration period for perfluorononanoic acid (PFNA), PFOS, the three precursors and the 6:2FTSA. However, this was not the case for long-chain PFCAs, whose elimination rates decreased with increasing chain length. PFAS accumulation in gammarids occurred via the trophic and respiratory pathways, in proportions varying with the carbon chain length and the terminal moiety. PMID:27139118

  19. Invasion of the Upper Mississippi River System by Saltwater Amphipods

    EPA Science Inventory

    Zoobenthos surveys of the Great Rivers of the Upper Mississippi River basin (Missouri, Mississippi, and Ohio Rivers) provided an opportunity for documenting a series of invasions by euryhaline amphipods. The corophiid amphipod Apocorophium lacustre was first found in the Ohio Ri...

  20. Cellular and molecular osmoregulatory responses to cadmium exposure in Gammarus fossarum (Crustacea, Amphipoda).

    PubMed

    Issartel, Julien; Boulo, Viviane; Wallon, Sophie; Geffard, Olivier; Charmantier, Guy

    2010-10-01

    Osmoregulation represents a reliable indicator of the physiological state of crustaceans. It is mainly effected in gills via Na(+)/K(+)-ATPase (NKA) providing the major driving force for ion transport. In the present study conducted in the freshwater amphipod Gammarus fossarum, the impact of an exposure to 15 μg Cd L(-1) for 3 and 7d was investigated on the haemolymph osmolality (HO), gill structure, NKA localization in gills and its relative expression. In Cd-exposed G. fossarum, mean HO significantly decreased compared to controls. In animals exposed for 3 and 7d, high inter-individual variations in HO values were noted, resulting in their separation into unimpacted, slightly impacted and impacted animals. In unimpacted individuals, gills retained their organization, showing a thicker gill epithelium than in controls; NKA fluorescence was continuously observed along the gill epithelium and was distributed on a broader area than in controls. In slightly impacted individuals, a thinner epithelium, a slight collapse of the gill and a lower NKA fluorescence were observed compared to unimpacted specimens. In impacted individuals, dramatic alterations of the gill structure, including hyperplasia and alteration of the pillars, resulting in the collapse of the gill and the disappearance of the haemolymphatic canals were observed, as well as very limited NKA fluorescence. Therefore, the degree of gill alteration and the intensity of NKA fluorescence observed in the different groups were correlated with their respective HO levels. The relative amount of the NKA α-subunit mRNA significantly increased in specimens exposed to Cd for 3d compared to controls, and then returned to control level after 7d. The relationships between the changes in HO values, NKA immunostaining and mRNA relative expression are discussed. These results confirm that HO represents a valuable biomarker to evaluate crustacean health, and they underline the interest to assess individual responses to

  1. Studies on the life-cycle of Ganeo tigrinus Mehra & Negi, 1928 (Digenea).

    PubMed

    Brinesh, R; Janardanan, K P

    2012-05-01

    The life-history stages of Ganeo tigrinus Mehra & Negi, 1928 infecting the Indian bull frog Hoplobatrachus tigerinus (Daudin) are described, those from cercaria to egg-producing adult having been established in the laboratory. Non-virgulate xiphidiocercariae are released by the planorbid snail Indoplanorbis exustus (Deshayes). Metacercariae occur in the haemocoel of dragonfly nymphs and become infective to the frog H. tigerinus within 15 days. The pre-patent period is 45 days. Growth and development of both metacercariae and adults are described in detail. Comments on the systematic position of Ganeo Klein, 1905 are included.

  2. Modeling the contribution of toxicokinetic and toxicodynamic processes to the recovery of Gammarus pulex populations after exposure to pesticides.

    PubMed

    Galic, Nika; Ashauer, Roman; Baveco, Hans; Nyman, Anna-Maija; Barsi, Alpar; Thorbek, Pernille; Bruns, Eric; Van den Brink, Paul J

    2014-07-01

    Because aquatic macroinvertebrates may be exposed regularly to pesticides in edge-of-the-field water bodies, an accurate assessment of potential adverse effects and subsequent population recovery is essential. Standard effect risk assessment tools are not able to fully address the complexities arising from multiple exposure patterns, nor can they properly address the population recovery process. In the present study, we developed an individual-based model of the freshwater amphipod Gammarus pulex to evaluate the consequences of exposure to 4 compounds with different modes of action on individual survival and population recovery. Effects on survival were calculated using concentration-effect relationships and the threshold damage model (TDM), which accounts for detailed processes of toxicokinetics and toxicodynamics. Delayed effects as calculated by the TDM had a significant impact on individual survival and population recovery. We also evaluated the standard assessment of effects after short-term exposures using the 96-h concentration-effect model and the TDM, which was conservative for very short-term exposure. An integration of a TKTD submodel with a population model can be used to explore the ecological relevance of ecotoxicity endpoints in different exposure environments.

  3. Haemolymph [Na+] and [Cl-] loss in Gammarus fossarum exposed in situ to a wide range of acidic streams.

    PubMed

    Felten, Vincent; Guerold, François

    2004-10-21

    The acid-sensitive amphipod Gammarus fossarum was exposed in situ for 24, 96 and 168 h to 18 streams (9 draining from granite and 9 draining from sandstone bedrock), selected in order to provide a wide range of acidification. After 24 h, exposure to slightly acidic (6.00 < or = pH < or = 5.50) and strongly acidic water (pH < 5.50) led to a severe and significant depletion in haemolymph [Na+] and [Cl-] compared to organisms exposed in circumneutral water. Highly significant linear correlations between stream mean pH value and haemolymph [Na+] and [Cl-] were observed for each exposure time on each bedrock. Organisms exposed to slightly acid streams draining granite bedrock (pH = 5.71, pH = 5.81) showed a physiological adaptation after 96 h of exposure, while animals in acidic sandstone streams did not. Results of this study indicate that haemolymph [Na+] and [Cl-] in G. fossarum could be an effective ecophysiological marker for monitoring freshwater ecosystem acidification.

  4. Gender differences in responses in Gammarus pulex exposed to BDE-47: A gel-free proteomic approach.

    PubMed

    Gismondi, E; Mazzucchelli, G; De Pauw, E; Joaquim-Justo, C; Thomé, J P

    2015-12-01

    Very few ecotoxicological studies have considered differences in toxic effects on male and female organisms. Here, we investigated protein expression differences in caeca of Gammarus pulex males and females under control conditions (unexposed) and after 96h exposure to BDE-47. Using gel-free proteomic analysis, we have identified 45 proteins, of which 25 were significantly differently expressed according to sex and/or BDE-47 exposure. These proteins were involved in several biological processes such as energy metabolism, chaperone proteins, or transcription/translation. In unexposed amphipods, 11 proteins were significantly over-expressed in females, and 6 proteins were over-expressed in males. Under BDE-47 stress, 7 proteins were differently impacted according to sex. For example, catalase was over-expressed in exposed females and under-expressed in exposed males, as compared to respective controls. Conversely, proteins involved in energy metabolism were up-regulated in males and down-regulated in females. Our proteomic study showed differences in responses of males and females to BDE-47 exposure, emphasizing that sex is a confounding factor in ecotoxicological assessment. However, due to the limited information existing in databases on Gammarids, it was difficult to define a BDE-47 mechanism of action. The gel-free proteomic seems to be a promising method to develop in future ecotoxicological studies and thus, to improve our understanding of the mechanism of action of xenobiotics. PMID:26256056

  5. Suspended particles only marginally reduce pyrethroid toxicity to the freshwater invertebrate Gammarus pulex (L.) during pulse exposure.

    PubMed

    Rasmussen, Jes Jessen; Cedergreen, Nina; Kronvang, Brian; Andersen, Maj-Britt Bjergager; Nørum, Ulrik; Kretschmann, Andreas; Strobel, Bjarne Westergaard; Hansen, Hans Christian Bruun

    2016-04-01

    Current ecotoxicological research on particle-associated pyrethroids in freshwater systems focuses almost exclusively on sediment-exposure scenarios and sediment-dwelling macroinvertebrates. We studied how suspended particles influence acute effects of lambda-cyhalothrin and bifenthrin on the epibenthic freshwater amphipod Gammarus pulex (L.) using brief pulse exposures followed by a 144 h post exposure recovery phase. Humic acid (HA) and the clay mineral montmorillonite (MM) were used as model sorbents in environmentally realistic concentrations (5, 25 and 125 mg L(-1)). Mortality of G. pulex was recorded during the post exposure recovery phase and locomotor behavior was measured during exposure to lambda-cyhalothrin. We found that HA in concentrations ≥25 mg L(-1) adsorbed the majority of pyrethroids but only reduced mortality of G. pulex up to a factor of four compared to pyrethroid-only treatments. MM suspensions adsorbed a variable fraction of pyrethroids (10% for bifenthrin and 70% for lambda-cyhalothrin) but did not significantly change the concentration-response relationship compared to pure pyrethroid treatments. Behavioral responses and immobilisation rate of G. pulex were reduced in the presence of HA, whereas behavioral responses and immobilisation rate were increased in the presence of MM. This indicates that G. pulex was capable of sensing the bioavailable fraction of lambda-cyhalothrin. Our results imply that suspended particles reduce to only a limited extent the toxicity of pyrethroids to G. pulex and that passive uptake of pyrethroids can be significant even when pyrethroids are adsorbed to suspended particles. PMID:26831865

  6. Modulatory effects of the serotonergic and histaminergic systems on reaction to light in the crustacean Gammarus pulex.

    PubMed

    Perrot-Minnot, Marie-Jeanne; Dion, Emilie; Cézilly, Frank

    2013-12-01

    Serotonin modulates reaction to light in many animals. In the freshwater amphipod Gammarus pulex, exogenous administration of serotonin induces a transient reversal of photic behaviour from strong photophobia to photophily. We have elucidated further the neuromodulation of photic behaviour in G. pulex by using in vivo pharmacology and behavioural testing. Using several mammalian 5-HT receptor antagonists and agonists, we provide evidence for a role of serotonin receptors in the 5-HT-dependent regulation of G. pulex photic behaviour, possibly involving 5-HTR2 subtype. Serotonin-induced photophily was blocked by the 5-HT receptor antagonists, mianserin, cyproheptadine, and ritanserin, but not by ketanserin and methiothepin. In addition, two agonists at 5-HT receptor, mCPP and α-methylserotonin, partially mimicked 5-HT-induced photophily. The natural photophobia of G. pulex was also decreased by exogenous administration of the histamine receptor antagonist cimetidine, suggesting that photic behaviour may be controlled by more complex interactions between serotonergic and histaminergic systems.

  7. Multiscale variability of amphipod assemblages in Posidonia oceanica meadows

    NASA Astrophysics Data System (ADS)

    Sturaro, Nicolas; Lepoint, Gilles; Vermeulen, Simon; Gobert, Sylvie

    2015-01-01

    The study of spatial patterns is important in understanding the causes of the distribution and abundance of organisms, and it also provides a valuable basis for management and conservation. Amphipod crustaceans are key organisms in seagrass ecosystems. However, little attention has been paid to the spatial scales at which amphipod assemblages may vary. We examined variability patterns of amphipod populations inhabiting Posidonia oceanica meadows, over spatial scales spanning four orders of magnitude (1 to 1000 meters) and for two consecutive years. This study reports the scales that contributed most to spatial variation of amphipod assemblages and explores the potential processes driving the observed patterns, with particular emphasis on habitat features. The number of species, the diversity, and the density of some species varied substantially across years. For most species the highest spatial variation in density and biomass occurred at small scales (1 and 10 meters). Based on density data, the structure of amphipod assemblages did not differ at any scales investigated. The patchiness that occurred at small scales may have been related to habitat features, but only weakly. Instead, we postulate that amphipod behavioral processes likely represent good explanatory factors. Although, small-scale spatial variability can be an important feature of amphipod assemblages in P. oceanica meadows, some patterns may have gone undetected because they occur at scales smaller than those investigated.

  8. Time budget and activity patterns of oncilla cats (Leopardus tigrinus) in captivity.

    PubMed

    Resende, Letícia de Souza; Neto, Glauce Lima e; Carvalho, Patrícia Gonçalves Duarte; Landau-Remy, Gabriella; Ramos-Júnior, Valdir de Almeida; Andriolo, Artur; Genaro, Gelson

    2014-01-01

    Researchers have reported on the diet of Leopardus tigrinus and ecological aspects, but studies of behavior are scarce. The aims of this study were to describe the time budget and activity patterns of 10 captive Leopardus tigrinus individuals. The group had an activity budget of 66% resting, 20.66% moving, 6.08% vigilant, 3.12% feeding, and 4.14% other activities during 720 hr of observations. The activity budgets of the males and females did not differ significantly; however, males ate more than did females. The nonhuman animals spent more time resting during the day than during the night. Moving, socializing, maintenance, and vigilance showed statistically higher mean values at night. Group analysis of the temporal pattern of behavior showed bimodal peaks. Activity levels were high from 5 a.m. to 6 a.m. and decreased through the day only to peak again at 7 p.m. Stereotypic pacing peaked at dawn and at dusk. Patterns of vigilance, feeding, and maintenance were also determined for the group during a 24-hr period. These results may be useful for the development of management plans and effective conservation strategies for captive cats.

  9. [Relation between ligninolytic and phospholipase activities in the fungus Lentinus tigrinus].

    PubMed

    Kadimaliev, D A; Shutova, V V; Teliatnik, V I; Revin, V V; Kezina, E V; Kudaeva, T V

    2014-01-01

    Effect of hydrocortisone, NaF, and FeSO4 on ligninolytic and phosphatase activity of the fungus Lentinus (Panus) tigrinus VKM F-3616D was investigated, Hydrocortisone and NaF were shown to inhibit the enzymes of the ligninolytic complex-laccase (EC 1.10.3.2), secretory peroxidase (EC 1.11.1.7), and Mn peroxidase (EC 1.11.1.13). FeSO4 exhibited no significant effect on the activity of these enzymes. Decreased activity of the enzymes of the ligninolytic complex was associatedwith inhibition of the activity and changes in the substrate specificity of phospholipase A2 (EC 3.1.1.4) in the presence of hydrocortisone of NaF. Cultivation of L. tigrinus in the presence of these compounds resulted in higher affinity of this enzyme to saturated fatty acids, while in the control and in the presence of FeSO4 affinity to unsaturated fatty acids was higher. PMID:25844453

  10. A laccase with HIV-1 reverse transcriptase inhibitory activity from the broth of mycelial culture of the mushroom Lentinus tigrinus.

    PubMed

    Xu, LiJing; Wang, HeXiang; Ng, TziBun

    2012-01-01

    A 59 kDa laccase with inhibitory activity against HIV-1 reverse transcriptase (IC(50) = 2.4 μM) was isolated from the broth of mycelial culture of the mushroom Lentinus tigrinus. The isolation procedure involved ion exchange chromatography on DEAE-cellulose and CM-cellulose, and gel filtration by fast protein liquid chromatography on Superdex 75. The laccase was adsorbed on both types of ion exchangers. About 95-fold purification was achieved with a 25.9% yield of the enzyme. The procedure resulted in a specific enzyme activity of 76.6 U/mg. Its N-terminal amino acid sequence was GIPDLHDLTV, which showed little similarity to other mushroom laccase and other Lentinus tigrinus strain laccase. Its characteristics were different from previously reported laccase of other Lentinus tigrinus strain. Maximal laccase activity was observed at a pH of 4 and at a temperature of 60°C, respectively. This study yielded the information about the potentially exploitable activities of Lentinus tigrinus laccase. PMID:22536022

  11. A Laccase with HIV-1 Reverse Transcriptase Inhibitory Activity from the Broth of Mycelial Culture of the Mushroom Lentinus tigrinus

    PubMed Central

    Xu, LiJing; Wang, HeXiang; Ng, TziBun

    2012-01-01

    A 59 kDa laccase with inhibitory activity against HIV-1 reverse transcriptase (IC50 = 2.4 μM) was isolated from the broth of mycelial culture of the mushroom Lentinus tigrinus. The isolation procedure involved ion exchange chromatography on DEAE-cellulose and CM-cellulose, and gel filtration by fast protein liquid chromatography on Superdex 75. The laccase was adsorbed on both types of ion exchangers. About 95-fold purification was achieved with a 25.9% yield of the enzyme. The procedure resulted in a specific enzyme activity of 76.6 U/mg. Its N-terminal amino acid sequence was GIPDLHDLTV, which showed little similarity to other mushroom laccase and other Lentinus tigrinus strain laccase. Its characteristics were different from previously reported laccase of other Lentinus tigrinus strain. Maximal laccase activity was observed at a pH of 4 and at a temperature of 60°C, respectively. This study yielded the information about the potentially exploitable activities of Lentinus tigrinus laccase. PMID:22536022

  12. An efficient PAH-degrading Lentinus (Panus) tigrinus strain: effect of inoculum formulation and pollutant bioavailability in solid matrices.

    PubMed

    Covino, Stefano; Cvancarová, Monika; Muzikár, Milan; Svobodová, Katerina; D'annibale, Alessandro; Petruccioli, Maurizio; Federici, Federico; Kresinová, Zdena; Cajthaml, Tomás

    2010-11-15

    This study comparatively investigated the PAH degradation ability of Lentinus tigrinus and Irpex lacteus in a historically polluted soil and creosote-impregnated shavings. With this regard, the effect of type of inoculum carrier (i.e., wheat straw, corn cobs and commercial pellets) and contaminant bioavailability was thoroughly determined. Although degradation performances of L. tigrinus were not significantly affected by the type of the support, they were invariably better than those of I. lacteus on both the polluted soil and the creosote-impregnated shavings. Although degradation efficiencies of all fungal microcosms were highly and significantly correlated with bioavailability, certain PAHs, such as chrysene and benzo[a]pyrene, were removed by L. tigrinus from the polluted soil at amounts that exceeded about 2.3-fold their respective bioavailabilities. Degradation of PAHs was negatively correlated with their organic carbon sorption coefficients (K(oc)) and hydrophobicity (logP). The strength of linear association with the latter parameter, however, was not affected by the type of contaminated matrix in L. tigrinus-based microcosms while it was significantly larger in the historically polluted soil than in the creosote-impregnated shavings in I. lacteus ones. PMID:20728989

  13. Identifying a key host in an acanthocephalan-amphipod system.

    PubMed

    Bauer, Alexandre; Rigaud, Thierry

    2015-11-01

    Trophically transmitted parasites may use multiple intermediate hosts, some of which may be 'key-hosts', i.e. contributing significantly more to the completion of the parasite life cycle, while others may be 'sink hosts' with a poor contribution to parasite transmission. Gammarus fossarum and Gammarus roeseli are sympatric crustaceans used as intermediate hosts by the acanthocephalan Pomphorhynchus laevis. Gammarus roeseli suffers higher field prevalence and is less sensitive to parasite behavioural manipulation and to predation by definitive hosts. However, no data are available on between-host differences in susceptibility to P. laevis infection, making it difficult to untangle the relative contributions of these hosts to parasite transmission. Based on results from estimates of prevalence in gammarids exposed or protected from predation and laboratory infections, G. fossarum specimens were found to be more susceptible to P. laevis infection. As it is more susceptible to both parasite infection and manipulation, G. fossarum is therefore a key host for P. laevis transmission.

  14. Status of the amphipod Diporeia Spp. in Lake Superior, 2011

    EPA Science Inventory

    Amphipods of the genus Diporeia have historically been the dominant benthic macroinvertebrates in deeper waters of the Laurentian Great Lakes. Although Diporeia populations in the lower Great Lakes have experienced severe declines in recent years, densities have remained relativ...

  15. Effects of the acanthocephalan Polymorphus minutus and the microsporidian Dictyocoela duebenum on energy reserves and stress response of cadmium exposed Gammarus fossarum.

    PubMed

    Chen, Hui-Yu; Grabner, Daniel S; Nachev, Milen; Shih, Hsiu-Hui; Sures, Bernd

    2015-01-01

    Amphipods are commonly parasitized by acanthocephalans and microsporidians and co-infections are found frequently. Both groups of parasites are known to have severe effects on their host. For example, microsporidians can modify host sex ratio and acanthocephalans can manipulate the behavior of the amphipod to promote transmission to the final host. These effects influence host metabolism in general and will also affect the ability of amphipods to cope with additional stressors such as environmental pollution, e.g., by toxic metals. Here we tested the effects of sub-lethal concentrations of cadmium on glycogen and lipid levels, as well as on the 70kDa heat shock protein (hsp70) response of field collected Gammarus fossarum, which were naturally infected with microsporidians and the acanthocephalan Polymorphus minutus. Infected and uninfected G. fossarum were exposed to a nominal Cd concentration of 4 µg/L, which resembled measured aqueous Cd concentration of 2.9 µg/L in reconstituted water for 7 d at 15 °C in parallel to an unexposed control. After exposure gammarids were snap frozen, weighed, sexed and tested for microsporidian infection by PCR. Only individuals containing the microsporidian Dictyocoela duebenum were used for the further biochemical and metal analyses. P. minutus infected amphipods were significantly smaller than their uninfected conspecifics. Mortality was insignificantly increased due to cadmium exposure, but not due to parasite infection. Microsporidian infection in combination with cadmium exposure led to increased glycogen levels in female gammarids. An increase of glycogen was also found due to interaction of acanthocephalan and microsporidian infection. Elevated lipid levels were observed in all groups infected with microsporidians, while acanthocephalans had the opposite effect. A positive correlation of lipid and glycogen levels was observed. The general stress response measured in form of hsp70 was significantly increased in

  16. Effects of the acanthocephalan Polymorphus minutus and the microsporidian Dictyocoela duebenum on energy reserves and stress response of cadmium exposed Gammarus fossarum

    PubMed Central

    Nachev, Milen; Shih, Hsiu-Hui; Sures, Bernd

    2015-01-01

    Amphipods are commonly parasitized by acanthocephalans and microsporidians and co-infections are found frequently. Both groups of parasites are known to have severe effects on their host. For example, microsporidians can modify host sex ratio and acanthocephalans can manipulate the behavior of the amphipod to promote transmission to the final host. These effects influence host metabolism in general and will also affect the ability of amphipods to cope with additional stressors such as environmental pollution, e.g., by toxic metals. Here we tested the effects of sub-lethal concentrations of cadmium on glycogen and lipid levels, as well as on the 70kDa heat shock protein (hsp70) response of field collected Gammarus fossarum, which were naturally infected with microsporidians and the acanthocephalan Polymorphus minutus. Infected and uninfected G. fossarum were exposed to a nominal Cd concentration of 4 µg/L, which resembled measured aqueous Cd concentration of 2.9 µg/L in reconstituted water for 7 d at 15 °C in parallel to an unexposed control. After exposure gammarids were snap frozen, weighed, sexed and tested for microsporidian infection by PCR. Only individuals containing the microsporidian Dictyocoela duebenum were used for the further biochemical and metal analyses. P. minutus infected amphipods were significantly smaller than their uninfected conspecifics. Mortality was insignificantly increased due to cadmium exposure, but not due to parasite infection. Microsporidian infection in combination with cadmium exposure led to increased glycogen levels in female gammarids. An increase of glycogen was also found due to interaction of acanthocephalan and microsporidian infection. Elevated lipid levels were observed in all groups infected with microsporidians, while acanthocephalans had the opposite effect. A positive correlation of lipid and glycogen levels was observed. The general stress response measured in form of hsp70 was significantly increased in

  17. Influence of cinnamon and catnip on the stereotypical pacing of oncilla cats (Leopardus tigrinus) in captivity.

    PubMed

    Resende, Letícia de S; Pedretti Gomes, Karla C; Andriolo, Artur; Genaro, Gelson; Remy, Gabriella L; Almeida Ramos, Valdir de

    2011-01-01

    Nonhuman animals in captivity can experience environmental privation that results in their exhibiting abnormal behaviors. Environmental enrichment techniques can help improve their welfare. This study investigated the behavior of 8 zoo-housed oncilla cats (Leopardus tigrinus) in response to 2 odors (catnip and cinnamon) introduced individually into the animals' enclosures for 3 consecutive days. Proportion of scans spent engaging in stereotypical pacing were compared before, during, and after treatments. The addition of cinnamon reduced the proportion of pacing during and after enrichment (Wilcoxon: Z = 3.16, p < .001; Z = 3.16, p < .001, respectively), indicating a prolonged effect of the enrichment on the animals' behavior. Catnip appears to have elicited no significant difference in the stereotypic pacing before, during, or after the enrichment (Friedman: X(2) = 2.69; p = .260). The results highlight the potential use of cinnamon as a method of environmental enrichment for small captive-housed cats.

  18. Influence of cinnamon and catnip on the stereotypical pacing of oncilla cats (Leopardus tigrinus) in captivity.

    PubMed

    Resende, Letícia de S; Pedretti Gomes, Karla C; Andriolo, Artur; Genaro, Gelson; Remy, Gabriella L; Almeida Ramos, Valdir de

    2011-01-01

    Nonhuman animals in captivity can experience environmental privation that results in their exhibiting abnormal behaviors. Environmental enrichment techniques can help improve their welfare. This study investigated the behavior of 8 zoo-housed oncilla cats (Leopardus tigrinus) in response to 2 odors (catnip and cinnamon) introduced individually into the animals' enclosures for 3 consecutive days. Proportion of scans spent engaging in stereotypical pacing were compared before, during, and after treatments. The addition of cinnamon reduced the proportion of pacing during and after enrichment (Wilcoxon: Z = 3.16, p < .001; Z = 3.16, p < .001, respectively), indicating a prolonged effect of the enrichment on the animals' behavior. Catnip appears to have elicited no significant difference in the stereotypic pacing before, during, or after the enrichment (Friedman: X(2) = 2.69; p = .260). The results highlight the potential use of cinnamon as a method of environmental enrichment for small captive-housed cats. PMID:22044295

  19. Expansion of alien gammarids in the Vistula Lagoon and the Vistula Delta (Poland).

    PubMed

    Dobrzycka-Krahel, Aldona; Tarała, Anna; Chabowska, Anna

    2013-06-01

    Amphipod crustaceans belong to the most successful invaders of aquatic environments. The work provides information concerning the spatial and temporal scales of expansion of four alien gammarid amphipods (three of them of Ponto-Caspian and one of North American origin): Pontogammarus robustoides (G.O. Sars, 1894), Obesogammarus crassus (G.O. Sars, 1894), Dikerogammarus haemobaphes (Eichwald, 1841), and Gammarus tigrinus Sexton, 1939 in the Vistula Lagoon (VL) and the Vistula Delta (VD) in 2008-2010. The mean abundance of these gammarids in nearshore zones was 382 ind m(-2) in VL and 89 ind m(-2) in VD. Their mean biomasses were likewise greater in VL (0.91 g m(-2)) than in VD (0.49 g m(-2)). G. tigrinus was the most dominant species in both nearshore zones of VL and VD and attained the highest frequency in these areas. The study gives evidence of total extinction of native gammarid species.

  20. [Influence of lignin and oxygen on the growth and the lipid formation of the fungus Lentinus tigrinus].

    PubMed

    IIvashechkin, A A; Sergeeva, Ia É; Lunin, V V; Bogdan, V I; Mysiakina, I S; Feofilova, E P

    2014-01-01

    During cultivation of the filamentous fungus Lentinus tigrinus on a medium containing lignin, a high oxygen content stimulated the growth of the fungus and contributed to the yield of lipids. A high content of phosphatidic acid and a reduction in the level of phosphatidylethanolamine and phosphatidylserine were first detected in the composition of phospholipids. Changes in the composition of neutral lipids, such as variation in the ratio of esterified and free sterols, have occurred; thus, the amount of sterol esters reduced simultaneously with a decrease in the content of free fatty acids. Based on the obtained results, the possible role of phosphatidic acid as a second messenger in the process of the consumption of lignin by the fungus Lentinus tigrinus is discussed. PMID:25757341

  1. Gammarus fossarum (Crustacea, Amphipoda) as a model organism to study the effects of silver nanoparticles.

    PubMed

    Mehennaoui, Kahina; Georgantzopoulou, Anastasia; Felten, Vincent; Andreï, Jennifer; Garaud, Maël; Cambier, Sébastien; Serchi, Tommaso; Pain-Devin, Sandrine; Guérold, François; Audinot, Jean-Nicolas; Giambérini, Laure; Gutleb, Arno C

    2016-10-01

    Amphipods are one of the most important components of freshwater ecosystems. Among them, gammarids are the most widespread group in Europe and are often used as bioindicators and model organisms in ecotoxicology. However, their use, especially of Gammarus fossarum for the study of the environmental impact of nanoparticles, has been rather limited so far. G. fossarum was selected to assess effects of well-characterized chemically synthesized silver nanoparticles (AgNPs 20nm and 200nm) and "green" laboratory synthetized (from plant leaf extracts) AgNPs (AgNPs 23nm and 27nm). AgNO3 was used as a positive control to compare AgNPs effects and silver ions effects. A multibiomarker approach was used to investigate the sub-lethal effects of AgNPs on physiological and behavioural responses of G. fossarum. Two different experiments were carried out. In a preliminary experiment, two populations of G. fossarum (G.f1 and G.f2) were tested for sensitivity differences and the most sensitive one was exposed, in a final experiment, to sub-lethal concentrations of AgNO3 and the most toxic AgNPs. AgNO3 and AgNPs 23nm led to a significant decrease in survival rates, osmoregulation and locomotor activity. Ag internalisation, performed with Secondary Ion Mass Spectrometry (SIMS), showed the presence of silver in gills of G.f2 exposed to AgNPs 23 and 27nm. This study highlighted the influence of method of synthesis on ion release, uptake and toxic effects of AgNPs on G. fossarum. Osmoregulation appeared to be an effective biomarker indicating the physiological health status of G. fossarum. Locomotor activity, which was the most impacted response, reflects the potential effects of released ions from AgNPs 23nm at the population level as locomotion is necessary for foraging, finding mates and escaping from predators. Therefore, we propose G. fossarum as a suitable model for environmental nanotoxicology, providing information both at individual and population levels. PMID:27328878

  2. Proximate composition and functionality of the culinary-medicinal tiger sawgill mushroom, Lentinus tigrinus (higher Basidiomycetes), from the Philippines.

    PubMed

    Dulay, Rich Milton R; Arenas, Minerva C; Kalaw, Sofronio P; Reyes, Renato G; Cabrera, Esperanza C

    2014-01-01

    The proximate composition and functionality of Lentinus tigrinus were evaluated to establish and popularize this mushroom as functional food source. The evaluation of functionality focused on the antibacterial and hypoglycemic activities of the mushroom extracts. An acute single oral dose toxicity test in mice was used for its biosafety analysis. The pileus contained higher amounts of protein (25.9%), fat (2.1%), and ash (7.4%) and a higher energetic value (142.1 kcal/100 g) than the corresponding stipe, whereas the stipe contained higher amounts of total carbohydrates (67.7%), which consist of dietary fiber (63.0%) and reducing sugar (4.7%), than the pileus. Biosafety analysis confirmed that L. tigrinus is an edible mushroom species; it was found to be toxicologically safe in imprinting control region mice. The administration of lyophilized hot water extract of the fruiting body (both 100 and 250 mg/ kg doses) to diabetic mice significantly lowered the glucose level by 26.9% in the third week, which was significantly comparable to the results of the antidiabetic agent glibenclamide, which was used as a positive control. In vitro antibacterial assay showed that the ethanolic extract of the fruiting body and the immobilized secondary mycelia had high antibacterial activities against Staphylococcus aureus but not on Escherichia coli. Combining its useful nutrients and significant biological properties, L. tigrinus can be considered a natural source of safe nutraceuticals. PMID:24940907

  3. Lentinus (Panus) tigrinus augmentation of a historically contaminated soil: matrix decontamination and structure and function of the resident bacterial community.

    PubMed

    Federici, E; Giubilei, M A; Cajthaml, T; Petruccioli, M; D'Annibale, A

    2011-02-28

    The ability of Lentinus tigrinus to grow and to degrade persistent aromatic hydrocarbons in aged contaminated soil was assessed in this study. L. tigrinus extensively colonized the soil; its degradation activity after 60 d incubation at 28°C, however, was mostly limited to dichloroaniline isomers, polychlorinated benzenes and diphenyl ether while the fungus was unable to deplete 9,10-anthracenedione and 7-H-benz[DE]anthracene-7-one which were the major soil contaminants. Although clean-up levels were limited, both density of cultivable heterotrophic bacteria and richness of the resident bacterial community in L. tigrinus microcosms (LtM) increased over time to a significantly larger extent than the respective amended incubation controls (1.9×10(9) CFU g(-1) vs. 1.0×10(9) CFU g(-1) and 37 vs. 16, respectively). Naphthalene- and catechol 2,3-dioxygenase gene copy numbers, however, decreased over time at a higher rate in LtM than in incubation controls likely due to a higher stimulation on heterotrophs than xenobiotics-degrading community members. PMID:21177025

  4. Parasite-induced alteration of plastic response to predation threat: increased refuge use but lower food intake in Gammarus pulex infected with the acanothocephalan Pomphorhynchus laevis.

    PubMed

    Dianne, Lucile; Perrot-Minnot, Marie-Jeanne; Bauer, Alexandre; Guvenatam, Arnaud; Rigaud, Thierry

    2014-03-01

    Larvae of many trophically-transmitted parasites alter the behaviour of their intermediate host in ways that increase their probability of transmission to the next host in their life cycle. Before reaching a stage that is infective to the next host, parasite larvae may develop through several larval stages in the intermediate host that are not infective to the definitive host. Early predation at these stages results in parasite death, and it has recently been shown that non-infective larvae of some helminths decrease such risk by enhancing the anti-predator defences of the host, including decreased activity and increased sheltering. However, these behavioural changes may divert infected hosts from an optimal balance between survival and foraging (either seeking food or a mate). In this study, this hypothesis was tested using the intermediate host of the acanthocephalan parasite Pomphorhynchus laevis, the freshwater amphipod Gammarus pulex. We compared activity, refuge use, food foraging and food intake of hosts experimentally infected with the non-infective stage (acanthella), with that of uninfected gammarids. Behavioural assays were conducted in four situations varying in predation risk and in food accessibility. Acanthella-infected amphipods showed an increase in refuge use and a general reduction in activity and food intake. There was no effect of parasite intensity on these traits. Uninfected individuals showed plastic responses to water-borne cues from fish by adjusting refuge use, activity and food intake. They also foraged more when the food was placed outside the refuge. At the intra-individual level, refuge use and food intake were positively correlated in infected gammarids only. Overall, our findings suggest that uninfected gammarids exhibit risk-sensitive behaviour including increased food intake under predation risk, whereas gammarids infected with the non-infective larvae of P. laevis exhibit a lower motivation to feed, irrespective of predation risk

  5. Parasite-induced alteration of plastic response to predation threat: increased refuge use but lower food intake in Gammarus pulex infected with the acanothocephalan Pomphorhynchus laevis.

    PubMed

    Dianne, Lucile; Perrot-Minnot, Marie-Jeanne; Bauer, Alexandre; Guvenatam, Arnaud; Rigaud, Thierry

    2014-03-01

    Larvae of many trophically-transmitted parasites alter the behaviour of their intermediate host in ways that increase their probability of transmission to the next host in their life cycle. Before reaching a stage that is infective to the next host, parasite larvae may develop through several larval stages in the intermediate host that are not infective to the definitive host. Early predation at these stages results in parasite death, and it has recently been shown that non-infective larvae of some helminths decrease such risk by enhancing the anti-predator defences of the host, including decreased activity and increased sheltering. However, these behavioural changes may divert infected hosts from an optimal balance between survival and foraging (either seeking food or a mate). In this study, this hypothesis was tested using the intermediate host of the acanthocephalan parasite Pomphorhynchus laevis, the freshwater amphipod Gammarus pulex. We compared activity, refuge use, food foraging and food intake of hosts experimentally infected with the non-infective stage (acanthella), with that of uninfected gammarids. Behavioural assays were conducted in four situations varying in predation risk and in food accessibility. Acanthella-infected amphipods showed an increase in refuge use and a general reduction in activity and food intake. There was no effect of parasite intensity on these traits. Uninfected individuals showed plastic responses to water-borne cues from fish by adjusting refuge use, activity and food intake. They also foraged more when the food was placed outside the refuge. At the intra-individual level, refuge use and food intake were positively correlated in infected gammarids only. Overall, our findings suggest that uninfected gammarids exhibit risk-sensitive behaviour including increased food intake under predation risk, whereas gammarids infected with the non-infective larvae of P. laevis exhibit a lower motivation to feed, irrespective of predation risk

  6. Bioaccumulation and critical body burden of fluoranthene in estuarine amphipods

    SciTech Connect

    Driscoll, S.K.; Dickhut, R.; Schaffner, L.

    1995-12-31

    A standard estuarine sediment toxicity test organism, the amphipod Leptocheirus plumulosus, was exposed to {sup 14}C-fluoranthene, a polycyclic aromatic hydrocarbon that is ubiquitous in contaminated coastal sediments. In water-only toxicity tests, the 10-d LC50 was 187.2 nmol/L and the critical body burden associated with 50% mortality on day 8 was 0.694 {micro}mol fluoranthene-equivalents/gww tissue. These results suggest that L. plumulosus is more sensitive to fluoranthene than other species of amphipods that have been examined. Also, the critical body burden measured in water-only tests for this species is lower than the predicted value that is associated with death by accumulation of nonpolar organic compounds such as fluoranthene in other organisms. Sediment toxicity, bioaccumulation, ability to metabolize fluoranthene, elimination rate, and critical body burden of fluoranthene in L. plumulosus will be compared to results previously determined for the freshwater amphipods, Diporeia sp. and Hyalella azteca.

  7. Safety of the molluscicide Zequanox (R) to nontarget macroinvertebrates Gammarus lacustris (Amphipoda: Gammaridae) and Hexagenia spp. (Ephemeroptera: Ephemeridae)

    USGS Publications Warehouse

    Waller, Diane L.; Luoma, James A.; Erickson, Richard A.

    2016-01-01

    Zequanox® is a commercial formulation of the killed bacterium, Pseudomonas fluorescens (strain CL145A), that was developed to control dreissenid mussels. In 2014, Zequanox became the second product registered by the United States Environmental Protection Agency (USEPA) for use in open water environments as a molluscicide. Previous nontarget studies demonstrated the safety and selectivity of P. fluorescens CL154A, but the database on the toxicity of the formulation (Zequanox) is limited for macroinvertebrate taxa and exposure conditions. We evaluated the safety of Zequanox to the amphipod Gammarus lacustris lacustris, and nymphs of the burrowing mayfly, Hexagenia spp. at the maximum approved concentration (100 mg/L active ingredient, A.I.) and exposure duration (8 h). Survival of animals was assessed after 8 h of exposure and again at 24 and 96 h post-exposure. Histopathology of the digestive tract of control and treated animals was compared at 96 h post-exposure. The results showed no significant effect of Zequanox on survival of either species. Survival of G. lacustris exceeded 85% in all concentrations at all three sampling time points. Survival of Hexagenia spp. ranged from 71% (control) to 91% at 8 h, 89–93% at 24 h post-exposure, and 70–73% at 96 h post-exposure across all treatments. We saw no evidence of pathology in the visceral organs of treated animals. Our results indicate that application of Zequanox at the maximum approved concentration and exposure duration did not cause significant mortality or treatment-related histopathological changes to G. lacustris and Hexagenia spp.

  8. Bioaugmentation of a historically contaminated soil by polychlorinated biphenyls with Lentinus tigrinus

    PubMed Central

    2012-01-01

    Background Several species belonging to the ecological group of white-rot basidiomycetes are able to bring about the remediation of matrices contaminated by a large variety of anthropic organic pollutants. Among them, polychlorobiphenyls (PCBs) are characterized by a high recalcitrance due to both their low bioavailability and the inability of natural microbial communities to degrade them at significant rates and extents. Objective of this study was to assess the impact of a maize stalk-immobilized Lentinus tigrinus CBS 577.79 inoculant combined with soybean oil (SO), as a possible PCB-mobilizing agent, on the bioremediation and resident microbiota of an actual Aroclor 1260 historically contaminated soil under unsaturated solid-phase conditions. Results Best overall PCB depletions (33.6 ± 0.3%) and dechlorination (23.2 ± 1.3%) were found after 60 d incubation in the absence of SO where, however, the fungus appeared to exert adverse effects on both the growth of biphenyl- and chlorobenzoate-degrading bacteria and the abundance of genes coding for both biphenyl dioxygenase (bph) and catechol-2,3-dioxygenase. A significant (P < 0.001) linear inverse relationship between depletion yields and degree of chlorination was observed in both augmented and control microcosms in the absence of SO; conversely, this negative correlation was not evident in SO-amended microcosms where the additive inhibited the biodegradation of low chlorinated congeners. The presence of SO, in fact, resulted in lower abundances of both biphenyl-degrading bacteria and bph. Conclusions The PCB depletion extents obtained in the presence of L. tigrinus are by far higher than those reported in other remediation studies conducted under unsaturated solid phase conditions on actual site soils historically contaminated by Aroclor 1260. These results suggest that the bioaugmentation strategy with the maize stalk-immobilized mycelium of this species might be promising in the reclamation of PCB

  9. Identifying a key host in an acanthocephalan-amphipod system.

    PubMed

    Bauer, Alexandre; Rigaud, Thierry

    2015-11-01

    Trophically transmitted parasites may use multiple intermediate hosts, some of which may be 'key-hosts', i.e. contributing significantly more to the completion of the parasite life cycle, while others may be 'sink hosts' with a poor contribution to parasite transmission. Gammarus fossarum and Gammarus roeseli are sympatric crustaceans used as intermediate hosts by the acanthocephalan Pomphorhynchus laevis. Gammarus roeseli suffers higher field prevalence and is less sensitive to parasite behavioural manipulation and to predation by definitive hosts. However, no data are available on between-host differences in susceptibility to P. laevis infection, making it difficult to untangle the relative contributions of these hosts to parasite transmission. Based on results from estimates of prevalence in gammarids exposed or protected from predation and laboratory infections, G. fossarum specimens were found to be more susceptible to P. laevis infection. As it is more susceptible to both parasite infection and manipulation, G. fossarum is therefore a key host for P. laevis transmission. PMID:26303006

  10. Genotype Reconstruction of Paternity in European Lobsters (Homarus gammarus)

    PubMed Central

    Ellis, Charlie D.; Hodgson, David J.; André, Carl; Sørdalen, Tonje K.; Knutsen, Halvor; Griffiths, Amber G. F.

    2015-01-01

    Decapod crustaceans exhibit considerable variation in fertilisation strategies, ranging from pervasive single paternity to the near-ubiquitous presence of multiple paternity, and such knowledge of mating systems and behaviour are required for the informed management of commercially-exploited marine fisheries. We used genetic markers to assess the paternity of individual broods in the European lobster, Homarus gammarus, a species for which paternity structure is unknown. Using 13 multiplexed microsatellite loci, three of which are newly described in this study, we genotyped 10 eggs from each of 34 females collected from an Atlantic peninsula in the south-western United Kingdom. Single reconstructed paternal genotypes explained all observed progeny genotypes in each of the 34 egg clutches, and each clutch was fertilised by a different male. Simulations indicated that the probability of detecting multiple paternity was in excess of 95% if secondary sires account for at least a quarter of the brood, and in excess of 99% where additional sire success was approximately equal. Our results show that multiple paternal fertilisations are either absent, unusual, or highly skewed in favour of a single male among H. gammarus in this area. Potential mechanisms upholding single paternal fertilisation are discussed, along with the prospective utility of parentage assignments in evaluations of hatchery stocking and other fishery conservation approaches in light of this finding. PMID:26566271

  11. Genotype Reconstruction of Paternity in European Lobsters (Homarus gammarus).

    PubMed

    Ellis, Charlie D; Hodgson, David J; André, Carl; Sørdalen, Tonje K; Knutsen, Halvor; Griffiths, Amber G F

    2015-01-01

    Decapod crustaceans exhibit considerable variation in fertilisation strategies, ranging from pervasive single paternity to the near-ubiquitous presence of multiple paternity, and such knowledge of mating systems and behaviour are required for the informed management of commercially-exploited marine fisheries. We used genetic markers to assess the paternity of individual broods in the European lobster, Homarus gammarus, a species for which paternity structure is unknown. Using 13 multiplexed microsatellite loci, three of which are newly described in this study, we genotyped 10 eggs from each of 34 females collected from an Atlantic peninsula in the south-western United Kingdom. Single reconstructed paternal genotypes explained all observed progeny genotypes in each of the 34 egg clutches, and each clutch was fertilised by a different male. Simulations indicated that the probability of detecting multiple paternity was in excess of 95% if secondary sires account for at least a quarter of the brood, and in excess of 99% where additional sire success was approximately equal. Our results show that multiple paternal fertilisations are either absent, unusual, or highly skewed in favour of a single male among H. gammarus in this area. Potential mechanisms upholding single paternal fertilisation are discussed, along with the prospective utility of parentage assignments in evaluations of hatchery stocking and other fishery conservation approaches in light of this finding.

  12. Genotype Reconstruction of Paternity in European Lobsters (Homarus gammarus).

    PubMed

    Ellis, Charlie D; Hodgson, David J; André, Carl; Sørdalen, Tonje K; Knutsen, Halvor; Griffiths, Amber G F

    2015-01-01

    Decapod crustaceans exhibit considerable variation in fertilisation strategies, ranging from pervasive single paternity to the near-ubiquitous presence of multiple paternity, and such knowledge of mating systems and behaviour are required for the informed management of commercially-exploited marine fisheries. We used genetic markers to assess the paternity of individual broods in the European lobster, Homarus gammarus, a species for which paternity structure is unknown. Using 13 multiplexed microsatellite loci, three of which are newly described in this study, we genotyped 10 eggs from each of 34 females collected from an Atlantic peninsula in the south-western United Kingdom. Single reconstructed paternal genotypes explained all observed progeny genotypes in each of the 34 egg clutches, and each clutch was fertilised by a different male. Simulations indicated that the probability of detecting multiple paternity was in excess of 95% if secondary sires account for at least a quarter of the brood, and in excess of 99% where additional sire success was approximately equal. Our results show that multiple paternal fertilisations are either absent, unusual, or highly skewed in favour of a single male among H. gammarus in this area. Potential mechanisms upholding single paternal fertilisation are discussed, along with the prospective utility of parentage assignments in evaluations of hatchery stocking and other fishery conservation approaches in light of this finding. PMID:26566271

  13. Stages and duration of the cycle of the seminiferous epithelium in oncilla (Leopardus tigrinus, Schreber, 1775).

    PubMed

    Balarini, Maytê Koch; de Paula, Tarcízio Antônio Rego; da Matta, S L Pinto; Peixoto, J Vogas; Guião-Leite, F Lima; Rossi Júnior, J L; Czermak Junior, A C; Walker, N J

    2012-03-15

    Six adult Leopardus tigrinus (oncilla) were studied to characterize stages of the seminiferous epithelium cycle and its relative frequency and duration, as well as morphometric parameters of the testes. Testicular fragments were obtained (incisional biopsy), embedded (glycol methacrylate), and histologic sections examined with light microscopy. The cycle of the seminiferous epithelium was categorized into eight stages (based on the tubular morphology method). The duration of one seminiferous epithelium cycle was 9.19 d, and approximately 41.37 d were required for development of sperm from spermatogonia. On average, diameter of the seminiferous tubules was 228.29 μm, epithelium height was 78.86 μm, and there were 16.99 m of testicular tubules per gram of testis. Body weight averaged 2.589 kg, of which 0.06 and 0.04% were attributed to the testis and seminiferous tubules, respectively. In conclusion, there were eight distinct stages in the seminiferous epithelium, the length of the seminiferous epithelium cycle was close to that in domestic cats and cougars, and testicular and somatic indexes were similar to those of other carnivores of similar size.

  14. Oxidase reaction of the hybrid Mn-peroxidase of the fungus Panus tigrinus 8/18.

    PubMed

    Lisov, A V; Leontievsky, A A; Golovleva, L A

    2005-04-01

    The hybrid Mn-peroxidase of the fungus Panus tigrinus 8/18 oxidized NADH in the absence of hydrogen peroxide, this being accompanied by the consumption of oxygen. The reaction of NADH oxidation started after a period of induction and completely depended on the presence of Mn(II). The reaction was inhibited in the presence of catalase and superoxide dismutase. Oxidation of NADH by the enzyme or by manganese(III)acetate was accompanied by the production of hydrogen peroxide and superoxide radicals. In the presence of NADH, the enzyme was transformed into a catalytically inactive oxidized form (compound III), and the latter was inactivated with bleaching of the heme. The substrate of the hybrid Mn-peroxidase (Mn(II)) reduced compound III to yield the native form of the enzyme and prevented its inactivation. It is assumed that the hybrid Mn-peroxidase used the formed hydrogen peroxide in the usual peroxidase reaction to produce Mn(III), which was involved in the formation of hydrogen peroxide and thus accelerated the peroxidase reaction. The reaction of NADH oxidation is a peroxidase reaction and the consumption of oxygen is due to its interaction with the products of NADH oxidation. The role of Mn(II) in the oxidation of NADH consisted in the production of hydrogen peroxide and the protection of the enzyme from inactivation. PMID:15892614

  15. [Effect of wood modification on lignin consumption and synthesis of lignolytic enzymes by the fungus Panus (Lentinus) tigrinus].

    PubMed

    Kadimaliev, D A; Revin, V V; Atykian, N A; Samuilov, V D

    2003-01-01

    Lignin consumption and synthesis of lignolytic enzymes by the fungus Panus (Lentinus) tigrinus cultivated on solid phase (modified and unmodified birch and pine sawdusts) were studied. The fungus grew better and consumed more readily the birch lignin than the pine wood. Peroxidase activity was higher in the case of pine sawdust; laccase and lignolytic activities, in the case of birth sawdust. Treatment with ammonia or sulfuric acid decreased lignin consumption by the fungus cultivated on either medium. Modification of sawdust by ultrasound increased lignin consumption and may be recommended for accelerating biodegradation of lignocellulose substrates. PMID:14593869

  16. [Increased secretion of lignolytic enzymes by the Lentinus tigrinus fungus after addition of butanol and toluene in submerged cultivation].

    PubMed

    Kadimaliev, D A; Nadezhina, O S; Atykian, N A; Revin, V V; Parshin, A A; Lavrova, A I; Dukhovskis, P V

    2008-01-01

    We studied the effects of butanol and toluene on secretion of lignolytic enzymes by the Lentinus tigrinus fungus during submerged cultivation. Addition of butanol and toluene during the trophophase was followed by an increase in laccase and peroxidase activity of the culture and change in the composition of phospholipids and fatty acids. The ratio of phosphatidylcholine and phosphatidic acid decreased, while the amount of lysophosphatidylcholine, phosphatidylethanolamine, phosphoinositides, phosphatidylserine, and unsaturated fatty acids decreased. These changes resulted in an increase in the unsaturation index. PMID:18822780

  17. The legacy of a vanished sea: a high level of diversification within a European freshwater amphipod species complex driven by 15 My of Paratethys regression.

    PubMed

    Mamos, Tomasz; Wattier, Remi; Burzyński, Artur; Grabowski, Michał

    2016-02-01

    The formation of continental Europe in the Neogene was due to the regression of the Tethys Ocean and of the Paratethys Sea. The dynamic geology of the area and repetitious transitions between marine and freshwater conditions presented opportunities for the colonization of newly emerging hydrological networks and diversification of aquatic biota. Implementing mitochondrial and nuclear markers in conjunction with a large-scale sampling strategy, we investigated the impact of this spatiotemporal framework on the evolutionary history of a freshwater crustacean morphospecies. The Gammarus balcanicus species complex is widely distributed in the area previously occupied by the Paratethys Sea. Our results revealed its high diversification and polyphyly in relation to a number of other morphospecies. The distribution of the studied amphipod is generally characterized by very high local endemism and divergence. The Bayesian time-calibrated reconstruction of phylogeny and geographical distribution of ancestral nodes indicates that this species complex started to diversify in the Early Miocene in the central Balkans, partially in the shallow epicontinental sea. It is possible that there were several episodes of inland water colonization by local brackish water lineages. Subsequent diversification within clades and spread to new areas could have been induced by Alpine orogeny in the Miocene/Pliocene and, finally, by Pleistocene glaciations. The present distribution of clades, in many cases, still reflects Miocene palaeogeography of the area. Our results point out that investigations of the historical aspect of cryptic diversity in other taxa may help in a general understanding of the origins of freshwater invertebrate fauna of Europe.

  18. Scavenging amphipods from under the Ross Ice Shelf, Antarctica

    NASA Astrophysics Data System (ADS)

    Stockton, William L.

    1982-07-01

    Amphipods in the genus Orchomene were collected from under the Ross Ice Shelf, Antarctica, 400 km from the shelf edge at a depth of 600 m. A study of 992 individuals of the 3500 captured revealed that the population is dominated by the larger size classes. Two-thirds of the population is composed of males. Ovigerous females will approach and consume bait and females are multiply brooded. The source of nutrition for this population is not definitely known. Identifiable gut contents were bacteria mixed with sediment, pieces of crustacean carapaces, and tissue from apparently cannibalized conspecifics. It is an open question as to whether the population sampled is persistent over time and whether amphipods are common under all of the Ross Ice Shelf.

  19. Parasite-induced alteration of odour responses in an amphipod-acanthocephalan system.

    PubMed

    Stone, Charles F; Moore, Janice

    2014-11-01

    Odour-related behaviours in aquatic invertebrates are important and effective anti-predator behaviours. Parasites often alter invertebrate host behaviours to increase transmission to hosts. This study investigated the responses of the amphipod Hyalella azteca when presented with two predator chemical cues: (i) alarm pheromones produced by conspecifics and (ii) kairomones produced by a predatory Green Sunfish (Lepomis cyanellus). We compared the responses of amphipods uninfected and infected with the acanthocepalan parasite Leptorhynchiodes thecatus. Uninfected amphipods reduced activity and increased refuge use after detecting both the alarm pheromones and predator kairomones. Infected amphipods spent significantly more time being active and less time on the refuge than uninfected amphipods, and behaved as if they had not detected the chemical stimulus. Therefore, L. thecatus infections disrupt the amphipods' anti-predator behaviours and likely make their hosts more susceptible to predation. PMID:25200352

  20. In vivo and in vitro polycyclic aromatic hydrocarbons degradation by Lentinus (Panus) tigrinus CBS 577.79.

    PubMed

    Covino, Stefano; Svobodová, Katerina; Kresinová, Zdena; Petruccioli, Maurizio; Federici, Federico; D'Annibale, Alessandro; Cvancarová, Monika; Cajthaml, Tomás

    2010-05-01

    The ability of stationary and shaken Lentinus tigrinus CBS 577.79 liquid cultures to degrade a mixture of polycyclic aromatic hydrocarbons (PAHs) in N-rich (i.e., malt extract glucose, MEG) and in N-limited (low-N Kirk's medium, LNKM) media was investigated. Best results were obtained in shaken cultures where PAHs were degraded by 91% and 97% in MEG and LNKM, respectively; in stationary cultures, on the contrary, the degradation was never higher than 50%. Laccase activity was predominant on MEG while Mn-peroxidase (MnP) was preferentially produced in LNKM. The identification of degradation products showed the presence of several PAH derivatives, such as quinones, dicarboxylated and ring fission derivatives, presumably derived from the action of lignin-modifying enzymes. The presence of some degradation products (e.g., hydroxylated derivatives of anthrone and phenanthrene 9,10-dihydrodiol) suggested the possible involvement of cytochrome P-450-epoxide hydrolase system, the active form of which was found in 7-day-old cultures on MEG. In vitro experiments showed that the MnP from L. tigrinus had wider PAH substrate range and higher oxidation ability than the laccase produced by the same strain. PMID:20056409

  1. Biobleaching of Acacia kraft pulp with extracellular enzymes secreted by Irpex lacteus KB-1.1 and Lentinus tigrinus LP-7 using low-cost media.

    PubMed

    Afrida, Sitompul; Tamai, Yutaka; Watanabe, Toshihiro; Osaki, Mitsuru

    2014-08-01

    The white-rot fungi Irpex lacteus KB-1.1 and Lentinus tigrinus LP-7 have been shown in previous studies to have high biobleaching activity in vivo. The aim of this study was to investigate the activities and stabilities of extracellular enzymes, prepared from I. lacteus and L. tigrinus culture grown in three types of economical media of agricultural and forestry wastes, for biobleaching of Acacia oxygen-delignified kraft pulp using kappa number reduction as an indicator of delignification. After 3 days of incubation, the extracellular enzymes preparations from I. lacteus and L. tigrinus cultures in media of Acacia mangium wood powder supplemented with rice bran and addition 1 % glucose (WRBG), resulted in significant decrease of 4.4 and 6.7 %, respectively. A slightly higher kappa number reduction (7.4 %) was achieved with the combine extracellular enzymes from I. lacteus and L. tigrinus. One of the strategies for reducing the cost of enzyme production for treatment processes in the pulp and paper industry is the utilization of agricultural and forestry waste. Thus, WRBG has potential as a culture medium for producing stable lignolytic enzymes simply and economically.

  2. Biobleaching of Acacia kraft pulp with extracellular enzymes secreted by Irpex lacteus KB-1.1 and Lentinus tigrinus LP-7 using low-cost media.

    PubMed

    Afrida, Sitompul; Tamai, Yutaka; Watanabe, Toshihiro; Osaki, Mitsuru

    2014-08-01

    The white-rot fungi Irpex lacteus KB-1.1 and Lentinus tigrinus LP-7 have been shown in previous studies to have high biobleaching activity in vivo. The aim of this study was to investigate the activities and stabilities of extracellular enzymes, prepared from I. lacteus and L. tigrinus culture grown in three types of economical media of agricultural and forestry wastes, for biobleaching of Acacia oxygen-delignified kraft pulp using kappa number reduction as an indicator of delignification. After 3 days of incubation, the extracellular enzymes preparations from I. lacteus and L. tigrinus cultures in media of Acacia mangium wood powder supplemented with rice bran and addition 1 % glucose (WRBG), resulted in significant decrease of 4.4 and 6.7 %, respectively. A slightly higher kappa number reduction (7.4 %) was achieved with the combine extracellular enzymes from I. lacteus and L. tigrinus. One of the strategies for reducing the cost of enzyme production for treatment processes in the pulp and paper industry is the utilization of agricultural and forestry waste. Thus, WRBG has potential as a culture medium for producing stable lignolytic enzymes simply and economically. PMID:24699808

  3. Extraordinary micro-endemism in Australian desert spring amphipods.

    PubMed

    Murphy, N P; Adams, M; Guzik, M T; Austin, A D

    2013-03-01

    Increasing pressure for water in the Australian arid zone is placing enormous stress on the diverse endemic communities inhabiting desert springs. Detailed information about the evolutionary processes occurring within and between individual endemic species will help to develop effective and biologically relevant management strategies this fragile ecosystem. To help determine conservation priorities, we documented the genetic structure of the endemic freshwater amphipod populations in springs fed by the Great Artesian Basin in central Australia. Phylogenetic and phylogeographic history and genetic diversity measures were examined using nuclear and mitochondrial DNA from approximately 500 chiltoniid amphipods across an entire group of springs. Pronounced genetic diversity was identified, demonstrating that levels of endemism have been grossly underestimated in these amphipods. Using the GMYC model, 13 genetically divergent lineages were recognized as Evolutionarily Significant Units (ESUs), all of which could be considered as separate species. The results show that due to the highly fragmented ecosystem, these taxa have highly restricted distributions. Many of the identified ESUs are endemic to a very small number of already degraded springs, with the rarest existing in single springs. Despite their extraordinarily small ranges, most ESUs showed relative demographic stability and high levels of genetic diversity, and genetic diversity was not directly linked to habitat extent. The relatively robust genetic health of ESUs does not preclude them from endangerment, as their limited distributions ensure they will be highly vulnerable to future water extraction. PMID:23142695

  4. Imidacloprid perturbs feeding of Gammarus pulex at environmentally relevant concentrations.

    PubMed

    Agatz, Annika; Ashauer, Roman; Brown, Colin D

    2014-03-01

    Changes in food uptake by detritivorous macroinvertebrates could disrupt the ecosystem service of leaf litter breakdown, necessitating the study of shredding under anthropogenic influences. The impact of the neonicotinoid insecticide imidacloprid on the feeding rate of individual Gammarus pulex was measured at a daily resolution both during and after a 4-d exposure period. The authors found that imidacloprid inhibits feeding of G. pulex during exposure at concentrations ≥ 30 µg/L and that there was no recovery in feeding on transfer into clean media for 3 d. Exposure to imidacloprid at concentrations ≥ 0.81 µg/L and ≤ 9.0 µg/L resulted in increased feeding after exposure even though there was no significant effect on feeding during the exposure itself. Comparison with the literature shows that concentrations found to influence feeding lie within the range of estimated and measured environmental concentrations. Additionally, effects on feeding rate were observed at concentrations 2 orders of magnitude lower than those causing mortality. The lethal concentration for 50% of test organisms after 4 d of exposure (270 µg/L, literature data) and the effect concentration for a reduction in feeding by 50% (5.34 µg/L) were used for this comparison. The present study discusses the potential that effects on feeding may evoke effects at the population level or disturb leaf litter breakdown in the environment. PMID:24375767

  5. DIFFERENTIAL DISPLAY ANALYSES OF THE AMPHIPOD HYALELLA AZTECA EXPOSED TO ETHYNYLESTRADIOL AT THREE DIFFERENT TROPHIC LEVELS

    EPA Science Inventory

    A study was conducted to determine if differential display could be used to detect differences in gene expression in the amphipod, Hyalella azteca. In a study of synthetic estrogen attenuation in different aquatic media, amphipods were exposed to 20 ng/L 17 a-ethynylestradiol in...

  6. Parallel reduction in expression, but no loss of functional constraint, in two opsin paralogs within cave populations of Gammarus minus (Crustacea: Amphipoda)

    PubMed Central

    2013-01-01

    Background Gammarus minus, a freshwater amphipod living in the cave and surface streams in the eastern USA, is a premier candidate for studying the evolution of troglomorphic traits such as pigmentation loss, elongated appendages, and reduced eyes. In G. minus, multiple pairs of genetically related, physically proximate cave and surface populations exist which exhibit a high degree of intraspecific morphological divergence. The morphology, ecology, and genetic structure of these sister populations are well characterized, yet the genetic basis of their morphological divergence remains unknown. Results We used degenerate PCR primers designed to amplify opsin genes within the subphylum Crustacea and discovered two distinct opsin paralogs (average inter-paralog protein divergence ≈ 20%) in the genome of three independently derived pairs of G. minus cave and surface populations. Both opsin paralogs were found to be related to other crustacean middle wavelength sensitive opsins. Low levels of nucleotide sequence variation (< 1% within populations) were detected in both opsin genes, regardless of habitat, and dN/dS ratios did not indicate a relaxation of functional constraint in the cave populations with reduced or absent eyes. Maximum likelihood analyses using codon-based models also did not detect a relaxation of functional constraint in the cave lineages. We quantified expression level of both opsin genes and found that the expression of both paralogs was significantly reduced in all three cave populations relative to their sister surface populations. Conclusions The concordantly lowered expression level of both opsin genes in cave populations of G. minus compared to sister surface populations, combined with evidence for persistent purifying selection in the cave populations, is consistent with an unspecified pleiotropic function of opsin proteins. Our results indicate that phototransduction proteins such as opsins may have retained their function in cave

  7. Differential regulation of hsp70 genes in the freshwater key species Gammarus pulex (Crustacea, Amphipoda) exposed to thermal stress: effects of latitude and ontogeny.

    PubMed

    Cottin, Delphine; Foucreau, Natacha; Hervant, Frédéric; Piscart, Christophe

    2015-04-01

    Temperature is one of the main abiotic factors influencing the distribution and abundance of organisms. In the Rhône River Valley, populations of the crustacean Gammarus pulex are distributed along a 5 °C thermal gradient from the North to the South of the valley. In this present work, we investigated the heat shock response of G. pulex according to latitudinal distribution (northern vs. southern populations) and ontogeny (adults vs. embryos from early stages). We isolated two isoforms (one constitutive hsc70 and one inducible hsp70) of heat shock proteins 70 (HSP70) and quantitatively compared their amounts of mRNA after heat shocks, using real-time PCR. Whereas the hsc70 (constitutive) gene did not vary between the two populations, a significant effect of the population was observed on the expression of the hsp70 (inducible) gene in adult specimens. The northern population of amphipods showed a greater magnitude of induction and a 2 °C lower onset temperature when compared to the southern population, suggesting that the northern population is more affected by elevated temperature than the southern one. We demonstrated that the expression of hsp70 may play a crucial role in the persistence of biogeographical patterns of G. pulex, since it reflects the natural distribution of this species along the latitudinal thermal gradient. A differential regulation of hsc70 gene was also observed according to the ontogenetic stage, with a switch from heat inducible in early life stages to constitutively and highly expressed in adults. These findings demonstrate the importance of considering the entire life cycle to better understand the adaptive response to thermal stress.

  8. Metabolism and decompression tolerance of scavenging lysianassoid deep-sea amphipods

    NASA Astrophysics Data System (ADS)

    Treude, Tina; Janßen, Felix; Queisser, Wolfgang; Witte, Ursula

    2002-07-01

    Respiration, ammonia excretion and decompression tolerance were studied in several species of lysianassoid amphipods captured at four stations in the deep Arabian Sea with an isolated trap maintaining them at in situ temperature. The amphipods were decompressed from their ambient to atmospheric pressure during recovery. Six amphipods, belonging to the species Eurythenes gryllus, Paralicella caperesca and Abyssorchomene abyssorum, survived decompression from depths between 1920 and 4420 m. The physiological condition of these specimens was good inferred by the fact that their swimming and resting behaviour appeared normal, they reacted to disturbance by light and vibration, and were able to ingest food to maintain full guts. Most of the amphipods (421 individuals), however, were recovered dead, which allows information about their decompression tolerance and their vertical migration ability to be deduced. Weight-specific respiration rates of the deep-sea amphipods that were fed prior to the experiments were not lower than in shallow-water amphipods living at similar temperatures. Differences in respiration rates between the specimens are discussed with regard to body size, species specificity and food supply. Weight-specific ammonia excretion rates were extremely high when compared with shallow-water relatives, indicating a capability for rapid digestion. This may be an adaptation to the unpredictable food supply in the deep sea as it enables the amphipod to empty its digestive tract quickly, thus making it available for additional food. Rapid digestion also enables the animals to regain mobility soon after feeding, permitting them to move to new food sources.

  9. Chlorobenzoic acid degradation by Lentinus (Panus) tigrinus: in vivo and in vitro mechanistic study-evidence for P-450 involvement in the transformation.

    PubMed

    Stella, T; Covino, S; Křesinová, Z; D'Annibale, A; Petruccioli, M; Čvančarová, M; Cajthaml, T

    2013-09-15

    Aim of this work was to investigate the ability of Lentinus (Panus) tigrinus to degrade and detoxify a chlorobenzoate (CBA) mixture composed of mono-, di- and tri-chlorinated isomers. The degradation process was investigated as a function of both the growing medium (i.e. low N Kirk's and malt extract-glucose medium) and cultivation conditions (i.e. stationary and shaken cultures). The majority of CBAs were quantitatively degraded within the early 15 d from spiking with the notable exception of the double ortho-chlorinated compounds, 2,6-di-, 2,3,6-tri- and 2,4,6-tri-CBA. Analysis of the degradation intermediates indicated the occurrence of side chain reduction, hydroxylation and methylation reactions. Although CBAs stimulated laccase production, in vitro experiments with a purified L. tigrinus laccase isoenzyme demonstrated its inability to participate in the initial attack on CBAs even in the presence of redox mediators; similar results were found with a Mn-peroxidase isoenzyme. Conversely, prompt degradation was observed upon 1h incubation of CBAs with a purified microsomal fraction containing cytochrome P-450 monooxygenase. The nature of some reaction products (i.e. hydroxylated derivatives), the dependency of the reaction on NADPH and its susceptibility to either CO or piperonyl butoxide inhibition confirmed the involvement of L. tigrinus cytochrome P-450 in the early steps of CBA degradation. PMID:23892164

  10. Quantification of emerging micropollutants in an amphipod crustacean by nanoliquid chromatography coupled to mass spectrometry using multiple reaction monitoring cubed mode.

    PubMed

    Sordet, Martin; Berlioz-Barbier, Alexandra; Buleté, Audrey; Garric, Jeanne; Vulliet, Emmanuelle

    2016-07-22

    An innovative analytical method has been developed to quantify the bioaccumulation in an amphipod crustacean (Gammarus fossarum) of three micropollutants regarded as anthropic-pollution markers: carbamazepine, oxazepam, and testosterone. A liquid-liquid extraction assisted by salts, known as QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) was miniaturised and optimised, so it could be adapted to the low mass samples (approximatively 5mg dry weight). For this same reason and in order to obtain good sensitivity, ultra-trace analyses were carried out by means of nanoliquid chromatography. A preconcentration system by on-column trapping was optimised to increase the injection volume. In order to improve both sensitivity and selectivity, the multiple reaction monitoring cubed mode analyses (MRM(3)) were carried out, validated and compared to the classic MRM. To the best of our knowledge, this is the first time that MRM(3) is coupled to nanoliquid chromatography for the analysis and detection of organic micropollutants <300Da. The optimised extraction method exhibited recoveries superior to 80%. The limits of quantification of the target compounds were 0.3, 0.7 and 4.7ng/g (wet weight) for oxazepam, carbamazepine and testosterone, respectively and the limits of detection were 0.1, 0.3 and 2.2ng/g (wet weight), respectively. The intra- and inter-day precisions were inferior to 7.7% and 10.9%, respectively, for the three levels of concentration tested. The analytical strategy developed allowed to obtain limits of quantification lower than 1ng/g (wet weight) and to establish the kinetic bioconcentration of contaminants within G. fossarum. PMID:27324621

  11. Status of the Amphipod Diporeia spp. in Lake Superior, poster presentation

    EPA Science Inventory

    The amphipod Diporeia has historically been the dominant benthic macroinvertebrate in deeper waters of the Laurentian Great Lakes. Although Diporeia populations in the lower Great Lakes have experienced severe declines in recent years, densities have remained relatively stable i...

  12. Biomass and production of amphipods in low alkalinity lakes affected by acid precipitation.

    PubMed

    France, R L

    1996-01-01

    Population biomass and production of the amphipod Hyalella azteca (Saussure) were found to be related to alkalinity (ranging from 0.2 to 58.1 mg liter(-1)) in 10 Canadian Shield lakes in south-central Ontario. Biomass and production of amphipods in the two lakes characterized by spring depressions of pH below 5.0 were found to be lower than those for populations inhabiting lakes that did not experience such acid pulses. The proportional biomass of amphipods in relation to the total littoral zoobenthos community was lower in lakes of low alkalinity than in circumneutral or hardwater lakes. Because production in these amphipod populations is known to depend closely on population abundance, the labour-intensive derivation of production rates yields relatively little information for biomonitoring that cannot be obtained from abundance data alone. PMID:15093505

  13. Development of a chronic sediment toxicity test for marine benthic amphipods

    SciTech Connect

    DeWitt, T.H.; Redmond, M.S.; Sewall, J.E.; Swartz, R.C.

    1992-12-01

    The results of the research effort culminated in the development of a research method for assessing the chronic toxicity of contaminated marine and estuarine sediments using the benthic amphipod, Leptocheirus plumulosus. The first chapter describes the efforts at collecting, handling, and culturing four estuarine amphipods from Chesapeake Bay, including L. plumulosus. This chapter includes maps of the distribution and abundance of these amphipods within Chesapeake Bay and methodologies for establishing cultures of amphipods which could be readily adopted by other laboratories. The second chapter reports the development of acute and chronic sediment toxicity test methods for L. plumulosus, its sensitivity to non-contaminant environmental variables, cadmium, two polynuclear aromatic hydrocarbons, and contaminated sediment from Baltimore Harbor, MD. The third chapter reports the authors attempts to develop a chronic sediment toxicity test with Ampelisca abdita.

  14. A REFORMULATED, RECONSTITUTED WATER FOR TESTING THE FRESHWATER AMPHIPOD, HYALELLA AZTECA

    EPA Science Inventory

    Toxicity testing with the freshwater amphipod, Hyalella azteca, has routinely been conducted using nonstandard waters. Four waters tested for acceptability for aqueous reference toxicant testing with H. azteca. These included three formulated (standardized) waters: moderately har...

  15. Biomass and production of amphipods in low alkalinity lakes affected by acid precipitation.

    PubMed

    France, R L

    1996-01-01

    Population biomass and production of the amphipod Hyalella azteca (Saussure) were found to be related to alkalinity (ranging from 0.2 to 58.1 mg liter(-1)) in 10 Canadian Shield lakes in south-central Ontario. Biomass and production of amphipods in the two lakes characterized by spring depressions of pH below 5.0 were found to be lower than those for populations inhabiting lakes that did not experience such acid pulses. The proportional biomass of amphipods in relation to the total littoral zoobenthos community was lower in lakes of low alkalinity than in circumneutral or hardwater lakes. Because production in these amphipod populations is known to depend closely on population abundance, the labour-intensive derivation of production rates yields relatively little information for biomonitoring that cannot be obtained from abundance data alone.

  16. CHRONIC EFFECTS OF THE HERBICIDE DIURON ON FRESHWATER CLADOCERANS,AMPHIPODS,MIDGES,MINNOWS,WORMS, AND SNAILS

    EPA Science Inventory

    The chronic effects of the herbicide diuron on survival and reproduction of Daphnia pulex, and survival and growth of the amphipod Hyalella azteca, the midge Chironomus tentans, juvenile and embro/larval fathead minnows, Pimephales promelas, annelid worms, Lumbriculus variegatus,...

  17. Diversity and Distribution of Freshwater Amphipod Species in Switzerland (Crustacea: Amphipoda)

    PubMed Central

    Altermatt, Florian; Alther, Roman; Fišer, Cene; Jokela, Jukka; Konec, Marjeta; Küry, Daniel; Mächler, Elvira; Stucki, Pascal; Westram, Anja Marie

    2014-01-01

    Amphipods are key organisms in many freshwater systems and contribute substantially to the diversity and functioning of macroinvertebrate communities. Furthermore, they are commonly used as bioindicators and for ecotoxicological tests. For many areas, however, diversity and distribution of amphipods is inadequately known, which limits their use in ecological and ecotoxicological studies and handicaps conservation initiatives. We studied the diversity and distribution of amphipods in Switzerland (Central Europe), covering four major drainage basins, an altitudinal gradient of>2,500 m, and various habitats (rivers, streams, lakes and groundwater). We provide the first provisional checklist and detailed information on the distribution and diversity of all amphipod species from Switzerland. In total, we found 29 amphipod species. This includes 16 native and 13 non-native species, one of the latter (Orchestia cavimana) reported here for the first time for Switzerland. The diversity is compared to neighboring countries. We specifically discuss species of the genus Niphargus, which are often receiving less attention. We also found evidence of an even higher level of hidden diversity, and the potential occurrence of further cryptic species. This diversity reflects the biogeographic past of Switzerland, and suggests that amphipods are ideally suited to address questions on endemism and adaptive radiations, post-glaciation re-colonization and invasion dynamics as well as biodiversity-ecosystem functioning relationships in aquatic systems. PMID:25354099

  18. Nocturnal planktonic assemblages of amphipods vary due to the presence of coastal aquaculture cages.

    PubMed

    Fernandez-Gonzalez, V; Fernandez-Jover, D; Toledo-Guedes, K; Valero-Rodriguez, J M; Sanchez-Jerez, P

    2014-10-01

    Nocturnal pelagic swimming is common in the daily activity of peracarids in marine ecosystems. Fish farming facilities in coastal areas constitute an optimal artificial habitat for invertebrates such as amphipods, which can reach high abundance and biomass in fouling communities. Additionally, fish farms may modify the local oceanographic conditions and the distribution of pelagic communities. The aim of this study was to determine if nocturnal abundance and species composition of planktonic amphipod assemblages are affected by fish farm structures, using light traps as collecting method. A total of 809 amphipods belonging to 21 species were captured in farm areas, compared to 42 individuals and 11 species captured in control areas. The most important species contributing to the dissimilarity between farms and controls were the pelagic hyperiid Lestrigonus schizogeneios, the fouling inhabitants Ericthonius punctatus, Jassa marmorata, Stenothoe sp. and Caprella equilibra, and the soft-bottom gammarids Periculodes aequimanus and Urothoe pulchella. The great concentrations of planktonic amphipods at fish farm facilities is a result of the input of individuals from fouling communities attached to aquaculture facilities, along with the potential retention there of hyperiids normally present in the water column and migrant amphipods from soft sediments. Therefore, in addition to the effects of aquaculture on benthic communities, the presence of fish farms induces major changes in planktonic assemblages of invertebrates such as amphipods.

  19. Diversity and distribution of freshwater amphipod species in Switzerland (Crustacea: Amphipoda).

    PubMed

    Altermatt, Florian; Alther, Roman; Fišer, Cene; Jokela, Jukka; Konec, Marjeta; Küry, Daniel; Mächler, Elvira; Stucki, Pascal; Westram, Anja Marie

    2014-01-01

    Amphipods are key organisms in many freshwater systems and contribute substantially to the diversity and functioning of macroinvertebrate communities. Furthermore, they are commonly used as bioindicators and for ecotoxicological tests. For many areas, however, diversity and distribution of amphipods is inadequately known, which limits their use in ecological and ecotoxicological studies and handicaps conservation initiatives. We studied the diversity and distribution of amphipods in Switzerland (Central Europe), covering four major drainage basins, an altitudinal gradient of>2,500 m, and various habitats (rivers, streams, lakes and groundwater). We provide the first provisional checklist and detailed information on the distribution and diversity of all amphipod species from Switzerland. In total, we found 29 amphipod species. This includes 16 native and 13 non-native species, one of the latter (Orchestia cavimana) reported here for the first time for Switzerland. The diversity is compared to neighboring countries. We specifically discuss species of the genus Niphargus, which are often receiving less attention. We also found evidence of an even higher level of hidden diversity, and the potential occurrence of further cryptic species. This diversity reflects the biogeographic past of Switzerland, and suggests that amphipods are ideally suited to address questions on endemism and adaptive radiations, post-glaciation re-colonization and invasion dynamics as well as biodiversity-ecosystem functioning relationships in aquatic systems.

  20. Toxicity of various contaminants to two Ampeliscid amphipods and a rotifer

    SciTech Connect

    Dolah, R. Van; Maier, P.; Jones, J.; Fulton, M.; Scott, G.; Lewis, M.

    1995-12-31

    Comparative bioassays were completed on the amphipods Ampelisca abdita and A. verrilli, and the rotifer Branchionus plicatilis, to determine their relative sensitivity to cadmium and fluoranthene. All aqueous tests involved static exposures for 24 and 48 hrs in 30 pt seawater, except for the amphipod exposures in fluoranthene which involved a 96-hr exposure. The amphipod sediment assays involved 10-day static exposures to contaminant-spiked sediments. Rotifer tests involved 24 and 48 hr exposures to sediment porewater that was centrifuged from the spiked sediments. Results obtained from the aqueous bioassays indicated that both amphipod species were significantly more sensitive than the rotifer to all of the contaminants. Ampelisca abdita and A. verrilli were generally comparable in their sensitivity to cadmium and fluoranthene. Results obtained from the 10-day sediment bioassays on the amphipods indicated that A. verrilli was more sensitive than A. abdita to the cadmium exposures and both amphipod assays were much more sensitive than the rotifer assay. Only A. abdita showed significant mortality in the highest fluoranthene exposure of 50 mg/kg dry wt, 0.46% TOC.

  1. Biodiversity of brackish water amphipods (crustacean) in two estuaries, southeast coast of India.

    PubMed

    Mondal, Nityananda; Rajkumar, Mayalagu; Sun, Jun; Kundu, Sourav; Lyla, P S; Khan, Seyed Ajmal; Trilles, Jean Paul

    2010-12-01

    The present study about the gammarid amphipods of Vellar and Uppanar estuaries was performed during two seasons (pre-monsoon and post-monsoon, 2005-2006), respectively, in nine habitats: five in the Vellar estuary and four in the Uppanar estuary. Amphipod samples were collected from sediments, oyster beds, seaweeds, sea grass, and mangroves. A total of 29 species of gammarid amphipods were collected in each area. The surface water temperature ranged from 16°C to 26°C, the salinity from 20 to 32 psu, and the pH between 7.5 and 8.3. Dissolved oxygen ranged from 5.3 to 7.8 ml/l. The maximum abundance of amphipods was observed during the pre-monsoon (July to September) in Vellar mangrove, and it was minimum during the pre-monsoon in Uppanar sea grass. It was found that several physicochemical factors, such as salinity, temperature, dissolved oxygen, pH, and the substrate have a marked effect on the distribution and the relative abundance of amphipods. The ranges of species diversity, richness, dominance, and evenness in the Vellar and Uppanar estuaries were 1.58-4.15, 1.82-5.29, 0-0.11, and 0.96-1, respectively. Using multivariate analyses, in each estuary, it was possible to identify different communities of amphipod species according to their habitats.

  2. Nocturnal planktonic assemblages of amphipods vary due to the presence of coastal aquaculture cages.

    PubMed

    Fernandez-Gonzalez, V; Fernandez-Jover, D; Toledo-Guedes, K; Valero-Rodriguez, J M; Sanchez-Jerez, P

    2014-10-01

    Nocturnal pelagic swimming is common in the daily activity of peracarids in marine ecosystems. Fish farming facilities in coastal areas constitute an optimal artificial habitat for invertebrates such as amphipods, which can reach high abundance and biomass in fouling communities. Additionally, fish farms may modify the local oceanographic conditions and the distribution of pelagic communities. The aim of this study was to determine if nocturnal abundance and species composition of planktonic amphipod assemblages are affected by fish farm structures, using light traps as collecting method. A total of 809 amphipods belonging to 21 species were captured in farm areas, compared to 42 individuals and 11 species captured in control areas. The most important species contributing to the dissimilarity between farms and controls were the pelagic hyperiid Lestrigonus schizogeneios, the fouling inhabitants Ericthonius punctatus, Jassa marmorata, Stenothoe sp. and Caprella equilibra, and the soft-bottom gammarids Periculodes aequimanus and Urothoe pulchella. The great concentrations of planktonic amphipods at fish farm facilities is a result of the input of individuals from fouling communities attached to aquaculture facilities, along with the potential retention there of hyperiids normally present in the water column and migrant amphipods from soft sediments. Therefore, in addition to the effects of aquaculture on benthic communities, the presence of fish farms induces major changes in planktonic assemblages of invertebrates such as amphipods. PMID:25164018

  3. COMPARISON BETWEEN DEXMEDETOMIDINE-S-KETAMINE AND MIDAZOLAM-S-KETAMINE IN IMMOBILIZATION OF ONCILLA (LEOPARDUS TIGRINUS).

    PubMed

    Lima, Caio Filipe da Motta; Cortopassi, Silvia Renata Gaido; de Moura, Claudio Alves; de Mattos, Ewaldo; das Candeias, Isis Zanini; Pedron, Bruno Gregnanin; Teixeira, Rodrigo Hidalgo Friciello; Dias Neto, Ramiro das Neves

    2016-03-01

    Established immobilization protocols are required for safe procedures on wildlife and zoo animals. This study evaluated the cardiovascular, respiratory, and anesthetic effects of dexmedetomidine (40 μg/kg) with S-ketamine (5 mg/kg) and midazolam (0.5 mg/kg) with S-ketamine (5 mg/kg) in 12 specimens of oncilla (Leopardus tigrinus) at Quinzinho de Barros Municipal Zoo Park in Sorocaba, São Paulo, Brazil, between January and March 2010. Each animal underwent both protocols, totaling 24 anesthetic procedures. The dexmedetomidine-S-ketamine group (DK) showed a decrease in heart rate compared to initial values and significantly lower heart rate and oxyhemoglobin saturation values compared to Midazolam-S-Ketamine Group (MK). Four animals in DK had episodes of sinus pauses. Systemic blood pressure, respiratory frequency, and rectal temperature showed no significant differences between groups. The dexmedetomidine-S-ketamine group showed a greater degree of muscle relaxation and allowed for more thorough and longer oral evaluations. The dexmedetomidine-S-ketamine group had a shorter period of recumbency, longer period to return of muscle tone, and shorter recovery time. Two animals in MK did not reach recumbency. The dexmedetomidine-S-ketamine group had better qualities of induction and recovery. It may be concluded that both protocols can be safely used in oncillas. Midazolam-S-ketamine promotes effective chemical restraint for quick and minimally invasive procedures and dexmedetomidine-S-ketamine promotes effective chemical restraint for prolonged and more invasive procedures.

  4. Biodegradation potential and ligninolytic enzyme activity of two locally isolated Panus tigrinus strains on selected agro-industrial wastes.

    PubMed

    Ruqayyah, Tijani I D; Jamal, Parveen; Alam, Md Zahangir; Mirghani, Md Elwathig S

    2013-03-30

    The degradation potential and ligninolytic enzyme production of two isolated Panus tigrinus strains (M609RQY and M109RQY) were evaluated in this study. These strains were grown on three selected abundant agro-industrial wastes (rice straw; rice husk and cassava peel) under solid-state fermentation conditions. Degradation potential was determined by analyzing the chemical composition of the selected substrates before and after fermentation along with ligninolytic enzyme production. The strain M609RQY led to the highest lignin degradation of 40.81% on cassava peel, 11.25% on rice husk and 67.96% on rice straw. Both strains significantly increased the protein content of cassava peel. Rice husk stimulated maximum laccase (2556 U/L) and lignin peroxidase (24 U/L) production by the strains M109RQY and M609RQY, respectively. Furthermore, cassava peel stimulated maximum manganese-dependent peroxidase (141 U/L) production by the strain M109RQY. The de-lignified rice straw and the nutritionally-improved cassava peel could serve as potential animal feed supplements. PMID:23422153

  5. Are European lobsters (Homarus gammarus) susceptible to infection by a temperate Hematodinium sp.?

    PubMed

    Davies, Charlotte E; Rowley, Andrew F

    2015-05-01

    Hematodinium spp. infect over 40 species of crustaceans worldwide, but have not been reported to infect the European lobster, Homarus gammarus. In this study, Hematodinium parasites (a mixture of uni- and multinucleate trophont-like stages) were taken from donor crabs (Cancer pagurus) and injected into juvenile H. gammarus. Juvenile C. pagurus were also injected with the same inoculum. Haemolymph was taken at regular intervals and examined for the presence of Hematodinium using light microscopy and PCR, in two separate experiments of duration 4 and 8months. All lobsters were negative for Hematodinium whilst the C. pagurus challenged became infected. It is concluded that European lobsters are not susceptible to infection with a clade of Hematodinium that infects C. pagurus. PMID:25721169

  6. Role of sources and temporal sinks in a marine amphipod.

    PubMed

    Munguia, Pablo

    2015-02-01

    Spatially structured habitats challenge populations to have positive growth rates and species often rely on dispersing propagules to occupy habitats outside their fundamental niche. Most marine species show two main life stages, a dispersing stage and a sedentary stage affecting distribution and abundance patterns. An experimental study on Corophium acherusicum, a colonial tube-building amphipod, showed the strong influence that a source population can have on new habitats. More importantly, this study shows the effect of temporal sinks where newly established populations can show reduced growth rates if the propagule supply from a source is removed. Sink populations had a reduction in abundance and became male-biased as females left colonies. The consequences arising from short-term dispersal and temporal sinks could be due to different selection pressures at the source and sink populations. These consequences can become reflected in long-term dynamics of marine populations if we shift focus to non-random dispersal models incorporating behaviour and stage-dependent dispersal. PMID:25673002

  7. [Interrelation between the composition of lipids and products of their peroxidation and the secretion of ligninolytic enzymes during growth of Lentinus (Panus) tigrinus].

    PubMed

    Kadimaliev, D A; Nadezhina, O S; Atykian, N A; Revin, V V; Samuilov, V D

    2006-01-01

    Lipid composition, intracellular products of lipid peroxidation (LPO), and the activities of extracellular enzymes were studied during submerged cultivation of the xylotrophic fungus Lentinus (Panus) tigrinus VKM F-3616D. The maximum secretion of ligninolytic enzymes during the phase of active mycelium growth correlated with increased content of readily oxidized phospholipids and unsaturated fatty acids and with low content of the LPO products. In the idiophase, which was characterized by lower excretion of extracellular ligninolytic enzymes, the content of more stable phospholipids, saturated fatty acids, and LPO products increased. A relationship between the composition of mycelial lipids and the secretion of ligninolytic enzymes was revealed. PMID:17091587

  8. The Behavior Response of Amphipods Infected by Hedruris suttonae (Nematoda) and Pseudocorynosoma sp. (Acanthocephala).

    PubMed

    Casalins, Laura M; Brugni, Norma L; Rauque, Carlos A

    2015-12-01

    The manipulation of intermediate host behavior may increase chances of parasite transmission to the definitive host. In freshwater environments of the Neotropical Region, studies on behavioral manipulations by parasites are rare, and the majority of these consider only a single parasite species and/or 1 life stage of a particular parasite species. In Andean Patagonian lakes of Argentina, the amphipod Hyalella patagonica is infected by larvae of the fish nematode Hedruris suttonae and by the bird acanthocephalan Pseudocorynosoma sp. The 3 objectives of the present study were to determine whether H. suttonae and Pseudocorynosoma sp. differ in their effects on behavior of H. patagonica , whether such modification is associated with parasite development, and to assess the associations between behavioral traits. From naturally parasitized amphipods, activity (swimming levels) and phototaxis (light preference) was measured. Only in phototaxis trials did larvae of H. suttonae induce significantly higher levels of photophilia, suggesting that they are manipulative. Scores of activity and phototaxis were positive and significantly related for non-parasitized female amphipods and for amphipods parasitized by larvae of Pseudocorynosoma sp. but were not associated in amphipods parasitized with larvae of H. suttonae (infective and non-infective), suggesting that infection separated the relationship between these variables. PMID:26295566

  9. The Behavior Response of Amphipods Infected by Hedruris suttonae (Nematoda) and Pseudocorynosoma sp. (Acanthocephala).

    PubMed

    Casalins, Laura M; Brugni, Norma L; Rauque, Carlos A

    2015-12-01

    The manipulation of intermediate host behavior may increase chances of parasite transmission to the definitive host. In freshwater environments of the Neotropical Region, studies on behavioral manipulations by parasites are rare, and the majority of these consider only a single parasite species and/or 1 life stage of a particular parasite species. In Andean Patagonian lakes of Argentina, the amphipod Hyalella patagonica is infected by larvae of the fish nematode Hedruris suttonae and by the bird acanthocephalan Pseudocorynosoma sp. The 3 objectives of the present study were to determine whether H. suttonae and Pseudocorynosoma sp. differ in their effects on behavior of H. patagonica , whether such modification is associated with parasite development, and to assess the associations between behavioral traits. From naturally parasitized amphipods, activity (swimming levels) and phototaxis (light preference) was measured. Only in phototaxis trials did larvae of H. suttonae induce significantly higher levels of photophilia, suggesting that they are manipulative. Scores of activity and phototaxis were positive and significantly related for non-parasitized female amphipods and for amphipods parasitized by larvae of Pseudocorynosoma sp. but were not associated in amphipods parasitized with larvae of H. suttonae (infective and non-infective), suggesting that infection separated the relationship between these variables.

  10. Talitrid amphipods (Crustacea) as biomonitors for copper and zinc

    NASA Astrophysics Data System (ADS)

    Rainbow, P. S.; Moore, P. G.; Watson, D.

    1989-06-01

    Data are presented on the copper and zinc concentrations of four talitrid amphipod species (standard dry weight 10 mg), i.e. Orchestia gammarellus (Pallas), O. mediterranea Costa, Talitrus saltator Montagu and Talorchestia deshayesii (Audouin), from 31 sites in S.W. Scotland, N. Wales and S.W. England. More limited data are also presented for cadmium in O. gammarellus (three sites) and T. deshayesii (one site). In S.W. Scotland, copper concentrations were raised significantly in O. gammarellus from Whithorn and Auchencairn (Solway) and Loch Long and Holy Loch (Clyde). In S.W. England, copper concentrations were highest at Restronguet Creek, Torpoint and Gannel (Cornwall). Samples of O. gammarellus from Islay (inner Hebrides) taken adjacent to the effluent outfalls of local whisky distilleries fell into two groups based on copper concentrations (presumably derived from copper stills), the higher copper levels deriving from the more productive distilleries. High copper levels were found in T. saltator and Tal. deshayesii from Dulas Bay (Wales). Zinc levels in O. gammarellus were high in Holy Loch and Auchencairn (Scotland), Gannel and Torpoint (England) but extremely elevated (as was Zn in O. mediterranea) at Restronguet Creek. Zinc was also high in T. saltator from Dulas Bay (Wales), but not in Tal. deshayesii. Cadmium levels in O. gammarellus from Kilve (Bristol Channel) were much raised. These differences (a) conform with expectations of elevated bioavailability of these metals from well researched areas (S.W. England & N. Wales), and (b) identify hitherto unappreciated areas of enrichment in S.W. Scotland. Orchestia gammarellus is put forward as a suitable biomonitor for copper and zinc in British coastal waters.

  11. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Pacific Southwest): Amphipods

    SciTech Connect

    Grosse, D.J.; Pauley, G.B.

    1989-01-01

    Species profiles are literature summaries of the taxonomy, morphology, distribution, life history, and environmental requirements of coastal aquatic species. They are prepared to assist in environmental impact assessment. Amphipods are ubiquitous in distribution, but are most abundant in estuarine areas and other high nutrient areas. Hyperiidea are the third most abundant coastal marine crustacean zooplankton, following copepods and euphausiids. Benthic Gammaridea are an invaluable food source for many economically important fish and invertebrate species. Habitat preference and behavior of the major amphipod groups is highly variable. Intertidal California amphipods overlap the distribution of common genera of other regions around the world. Amphipoda are reported to be indicators of heavily polluted areas. They are considered the most efficient of all scavengers on the sea bottom and in shoreline areas. 66 refs., 5 figs.

  12. Response of amphipod assemblages to desalination brine discharge: Impact and recovery

    NASA Astrophysics Data System (ADS)

    de-la-Ossa-Carretero, J. A.; Del-Pilar-Ruso, Y.; Loya-Fernández, A.; Ferrero-Vicente, L. M.; Marco-Méndez, C.; Martinez-Garcia, E.; Sánchez-Lizaso, J. L.

    2016-04-01

    Desalination has become an important industry whose dense, high-salinity effluent has an impact on marine communities. Without adequate dilution, brine remains on the bottom increasing bottom salinity and affecting benthic communities. Amphipods showed high sensitivity to increased salinity produced by desalination brine discharge. A decrease in abundance and diversity of amphipods was detected at the station closest to the outfall, where salinity values reached 53. This salinity was later reduced by including a diffuser at the end of the pipeline. Six months after diffuser installation, amphipod abundance increased. During the first stage of this recovery, species such as Photis longipes recovered their abundance, others such as Microdeutopus versiculatus displayed opportunistic patterns, while others needed more time for recovery, e.g. Harpinia pectinata. These differences may be dependent on the organism living habits.

  13. Use of sublethal endpoints in sediment toxicity tests with the amphipod Hyalella azteca

    USGS Publications Warehouse

    Ingersoll, C.G.; Brunson, E.L.; Dwyer, F.J.; Hardesty, D.K.; Kemble, N.E.

    1998-01-01

    Short-term sediment toxicity tests that only measure effects on survival can be used to identify high levels of contamination but may not be able to identify marginally contaminated sediments. The objective of the present study was to develop a method for determining the potential sublethal effects of contaminants associated with sediment on the amphipod Hyalella azteca (e.g., reproduction). Exposures to sediment were started with 7- to 8-d-old amphipods. On day 28, amphipods were isolated from the sediment and placed in water-only chambers where reproduction was measured on day 35 and 42. Typically, amphipods were first in amplexus at about day 21 to 28 with release of the first brood between day 28 to 42. Endpoints measured included survival (day 28, 35, and 42), growth (as length and weight on day 28 and 42), and reproduction (number of young/female produced from day 28 to 42). This method was used to evaluate a formulated sediment and field-collected sediments with low to moderate concentrations of contaminants. Survival of amphipods in these sediments was typically >85% after the 28-d sediment exposures and the 14-d holding period in water to measure reproduction. Reproduction was more variable than growth; hence, more replicates might be needed to establish statistical differences among treatments. Previous studies have demonstrated that growth of H. azteca in sediment tests often provides unique information that can be used to discriminate toxic effects of exposure to contaminants. Either length or weight can be measured in sediment tests with H. azteca. However, additional statistical options are available if length is measured on individual amphipods, such as nested analysis of variance that can account for variance in length within replicates. Ongoing water-only studies testing select contaminants will provide additional data on the relative sensitivity and variability of sublethal endpoints in toxicity tests with H. azteca.

  14. Bioaccumulation of petroleum hydrocarbons in arctic amphipods in the oil development area of the Alaskan Beaufort Sea.

    PubMed

    Neff, Jerry M; Durell, Gregory S

    2012-04-01

    An objective of a multiyear monitoring program, sponsored by the US Department of the Interior, Bureau of Ocean Energy Management was to examine temporal and spatial changes in chemical and biological characteristics of the Arctic marine environment resulting from offshore oil exploration and development activities in the development area of the Alaskan Beaufort Sea. To determine if petroleum hydrocarbons from offshore oil operations are entering the Beaufort Sea food web, we measured concentrations of hydrocarbons in tissues of amphipods, Anonyx nugax, sediments, Northstar crude oil, and coastal peat, collected between 1999 and 2006 throughout the development area. Mean concentrations of polycyclic aromatic hydrocarbons (PAH), saturated hydrocarbons (SHC), and sterane and triterpane petroleum biomarkers (StTr) were not significantly different in amphipods near the Northstar oil production facility, before and after it came on line in 2001, and in amphipods from elsewhere in the study area. Forensic analysis of the profiles (relative composition and concentrations) of the 3 hydrocarbon classes revealed that hydrocarbon compositions were different in amphipods, surface sediments where the amphipods were collected, Northstar crude oil, and peat from the deltas of 4 North Slope rivers. Amphipods and sediments contained a mixture of petrogenic, pyrogenic, and biogenic PAH. The SHC in amphipods were dominated by pristane derived from zooplankton, indicating that the SHC were primarily from the amphipod diet of zooplankton detritus. The petroleum biomarker StTr profiles did not resemble those in Northstar crude oil. The forensic analysis revealed that hydrocarbons in amphipod tissues were not from oil production at Northstar. Hydrocarbons in amphipod tissues were primarily from their diet and from river runoff and coastal erosion of natural diagenic and fossil terrestrial materials, including seep oils, kerogens, and peat. Offshore oil and gas exploration and development

  15. Comparative acute toxicity to aquatic organisms of components of coal-derived synthetic fuels. [Selenastrum capricornutum; Nitzchia palea; Physa gyrina, Daphnia magna; Chironomus tentans; Gammarus minus; Pimephales promelas; Salmo gairdneri; Micropterus salmoides

    SciTech Connect

    Millemann, R.E.; Birge, W.J.; Black, J.A.; Cushman, R.M.; Daniels, K.L.; Franco, P.J.; Giddings, J.M.; McCarthy, J.F.; Stewart, A.J.

    1984-01-01

    In acute toxicity tests, green algae Selenaastrum capricornutum, diatoms Nitzschia palea, adult snails Physa gyrina, juvenile cladocerans Daphnia magna, larval midges Chironomus tentans, adult amphipods Gammarus minus, juvenile fathead minnows Pimephales promelas, and embryo-larva stages of rainbow trout Salmo gairdneri and largemouth bass Micropterus salmoides were exposed for 4 hours (algae), 48 hours (arthropods and snails), 96 hours (fathead minnows), 7 days (large-mouth bass), and 27 days (rainbow trout) to two phenols (phenol and ..beta..-naphthol), two azaarenes (quinoline and acridine), and two polycyclic aromatic hydrocarbons (naphthalene and phenanthrene) present in coal-derived oils. Median lethal or median effective concentrations (LC50s or EC50s) ranged from 0.03 mg/liter for phenanthrene and rainbow trout to 286.54 mg/liter for phenol and the green alga. The rainbow trout embryo-larva assay was the most sensitive of the test systems to all the chemicals except quinoline. For this last compound, systems with juvenile fathead minnows and largemouth bass embryos were the most sensitive. As test systems, fish embryos and larvae were the most sensitive, juvenile fathead minnows and arthropods had intermediate sensitivity, and algae and snails were the most resistant to the test compounds under the test conditions. Within each chemical class (phenols, azaarenes, and polycylcic aromatic hydrocarbons), toxicity increased with increased ring number except for the reversed relationship with the azaarenes and fathead minnows. Thus, ..beta..-naphthol (two rings) was 2 to 45 times more toxic than phenol (one ring); acridine (three rings) was 7 to 27 times more toxic than quinoline (two rings); and phenanthrene (three rings) was 3 to 9 times more toxic than naphthalene (two rings). 50 references.

  16. Vertical zonation patterns of scavenging amphipods from the Hadal zone of the Tonga and Kermadec Trenches

    NASA Astrophysics Data System (ADS)

    Blankenship, Lesley E.; Yayanos, A. Aristides; Cadien, Donald B.; Levin, Lisa A.

    2006-01-01

    Deep-sea trenches present an ideal system in which to study vertical zonation, though the difficulties inherent in studying these great depths have thus far deterred such research. Here, we present the first account of the structure and vertical zonation of the scavenging guild residing in the hadal habitat of the Tonga and Kermadec Trenches (SW Pacific Ocean). Four species of scavenging amphipod ( Eurythenes gryllus, Scopelocheirus schellenbergi, Hirondellea dubia, and Uristes sp. nov.) were captured with baited free-vehicle traps set 1 m above the seafloor and deployed to bottom depths between 5155 and 10,787 m. Each species occupied a distinct vertical zone of 3.5 km or less, and the scavenging amphipod assemblage vertically partitioned the hadal zone. Scavenging amphipod diversity and evenness sharply declined below 9 km. For S. schellenbergi and H. dubia, population structure was stratified ontogenetically. Early instars appeared to reside exclusively in the shallower depths of each species' vertical zone, and were functionally missing from the median and deeper regions. We captured brooding Uristes sp. nov. females, documenting the first bait-attendance event of brooding amphipods in the hadal zone. Separation of habitat in conjunction with deviations in reproductive traits, behaviors, and nutritional strategies may facilitate the coexistence of these four related species in this harsh and confining habitat.

  17. Interactions among four parasite species in an amphipod population from Patagonia.

    PubMed

    Rauque, C A; Semenas, L

    2013-03-01

    Parasites commonly share their hosts with specimens of the same or different parasite species, resulting in multiple parasites obtaining resources from the same host. This could potentially lead to conflicts between co-infecting parasites, especially at high infection intensities. In Pool Los Juncos (Patagonia, Argentina), the amphipod Hyalella patagonica is an intermediate host to three parasites that mature in birds (the acanthocephalan Pseudocorynosoma sp. and larval stages of two Cyclophyllidea cestodes), in addition to a microsporidian (Thelohania sp.), whose life cycle is unknown, but very likely to be monoxenous. The aim of this study was to describe interactions between these parasite species in their amphipod host population. Amphipods were collected monthly between June 2002 and January 2004 to assess parasite infection. Infection prevalence and mean intensity were greatest in larger male amphipods for all parasite species. We also found a positive association between Thelohania sp. and both Pseudocorynosoma sp. and Cyclophyllidea sp. 1 infections, though Pseudocorynosoma sp. and Cyclophyllidea sp. 1 were negatively associated with each other. We conclude that contrasting associations between parasite species may be associated with competition for both food intake and space in the haemocoel.

  18. The occurrence of Echinorhynchus salmonis Müller, 1784 in benthic amphipods in the Baltic Sea.

    PubMed

    Benesh, Daniel P; Aura, Raija-Liisa; Andersin, Ann-Britt; Tellervo Valtonen, E

    2015-01-01

    The acanthocephalan Echinorhynchus salmonis Müller, 1784 is a common parasite of salmonid fish, but it has rarely been reported from an intermediate host. Samples of benthic amphipods, Monoporeia affinis (Lindström), were taken from multiple, deep sites (usually below 70 m) in the Gulf of Bothnia over the course of more than a decade and examined for acanthocephalans. Overall, only 0.44% of 23 296 amphipods were infected, all with just a single worm. This prevalence is consistent with several previous reports of acanthocephalans in deep-water, benthic amphipods, but it appears low compared to that often reported for acanthocephalan species infecting littoral amphipods. Parasite occurrence did not exhibit a clear regional pattern (i.e. northern vs southern sites) nor did it have any relationship with site depth. At sites sampled over multiple years, parasite abundance was consistently low (mostly < 0.01), though two spikes in abundance (over 0.06) were also observed, indicating that infection can be substantially higher at particular times or in particular places. The median density of E. salmonis in samples containing the parasite was estimated as 8.4 cystacanths per m(2). PMID:26373577

  19. Vertical differences in species turnover and diversity of amphipod assemblages associated with coralline mats

    NASA Astrophysics Data System (ADS)

    Bueno, M.; Tanaka, M. O.; Flores, A. A. V.; Leite, F. P. P.

    2016-11-01

    Environmental gradients are common in rocky shore habitats and may determine species spatial distributions at different scales. In this study, we tested whether environmental filtering affects amphipod assemblages inhabiting coralline algal mats at different vertical heights in southeastern Brazil. Samples obtained from the upper and lower zones of the infralittoral fringe were used to estimate mat descriptors (algal mass, sediment retention, organic matter contents, grain size and sediment sorting) and describe amphipod assemblages (abundance, species richness and diversity indices). Coralline algal mats and amphipod assemblages were similar between intertidal zones in several aspects. However, a more variable retention of sediment (positively related to algal mass), together with the accumulation of larger grains lower on the shore, likely provide higher habitat heterogeneity that hosts generally more diverse (both α- and β-diversity, as well as higher species turnover) amphipod assemblages in the lower intertidal zone. Poorer assemblages in the upper intertidal zone are dominated by omnivores, while carnivorous species are more often found in richer assemblages in the lower intertidal zone, as predicted by traditional niche theory.

  20. PHOTOINDUCED TOXICITY OF PAHS AND ALKYLATED PAHS TO A MARINE INFAUNAL AMPHIPOD (RHEPOXYNIUS ABRONIUS)

    EPA Science Inventory

    The marine infaunal amphipod Rhepoxynius abronius was exposed in standard 10-day toxicity tests to sediments contaminated with parent or alkylated PAHs. After exposures, mortalities (LC50 values) and the ability to rebury in control sediment (EC50 values) were determined. Survivo...

  1. Influences of sedimentary organic matter quality on the bioaccumulation of 4-nonylphenol by estuarine amphipods.

    PubMed

    Hecht, Scott A; Gunnarsson, Jonas S; Boese, Bruce L; Lamberson, Janet O; Schaffner, Christian; Giger, Walter; Jepson, Paul C

    2004-04-01

    Nonylphenol (NP) is a moderately persistent, hydrophobic chemical with endocrine-disrupting and acute narcotic effects in aquatic biota. Concern exists about the ultimate fate of NP in aquatic ecosystems and the potential for bioaccumulation by benthic biota from the sediment with the potential for further transfer to higher trophic levels. Our goals were to determine if benthic amphipods bioaccumulate significant amounts of NP from sediment and to determine how additions of organic matter influence NP bioaccumulation by amphipods. Estuarine sediment was spiked with 14C-NP and enriched with two types of organic carbon (OC) sources of different nutritional qualities. Macrophytic algae (Ulva species) were used as a labile and nutritious OC source. Wood lignins were used as a refractory and low-nutrition OC source. Nonylphenol bioaccumulation was measured in Eohaustorius estuarius, Grandidierella japonica, and Corophium salmonis after 16 d of exposure. Nonylphenol accumulation was inversely proportional to OC quantity, but was unaffected by OC nutritional quality. Significant differences were found in the accumulation patterns between the three amphipod species. Mean biota-sediment accumulation factors ranged from 8.1 to 33.9 in E. estuarius, from 4.6 to 17.2 in G. japonica, and averaged 7.1 in male C. salmonis and 16.0 in female C. salmonis. These accumulation factors indicate that estuarine amphipods could constitute an important source of NP to higher trophic levels, such as juvenile fish. PMID:15095881

  2. STATUS OF THE AMPHIPOD DIPOREIA SPP. IN LAKE SUPERIOR, 1994-2000

    EPA Science Inventory

    The amphipod Diporeia spp. is the dominant component of the Great Lakes benthic macroinvertebrate fauna in terms of both numbers and biomass, and plays an important role in the ecosystem. The Great Lakes Water Quality Agreement calls for the use of Diporeia as an indicator of ec...

  3. The effect of Echinorhynchus borealis (Acanthocephala) infection on the anti-predator behavior of a benthic amphipod.

    PubMed

    Benesh, D P; Kitchen, J; Pulkkinen, K; Hakala, I; Valtonen, E T

    2008-04-01

    In benthic habitats, predators can generally not be detected visually, so olfaction may be particularly important for inducing anti-predation behaviors in prey organisms. Manipulative parasites infecting benthic hosts could suppress these responses so as to increase the probability of predation and thus trophic transmission. We studied how infection with the acanthocephalan Echinorhynchus borealis affects the response of the benthic amphipod Pallasea quadrispinosa to water conditioned by burbot (Lota lota), the parasite's definitive host. In normal lake water, refuge use by infected and uninfected amphipods was similar, but when exposed to burbot-conditioned water, uninfected amphipods spent much more time hiding than infected amphipods. Thus, rather than affecting ambient hiding behavior, E. borealis infection seems to alter host response to a predator. A group of amphipods sampled from a postglacial spring that is devoid of fish predators exhibited only a weak response to burbot-conditioned water, perhaps suggesting these anti-predator behaviors are costly to maintain. The hiding behavior of spring and infected amphipods was very similar. If the reduced refuge use by the spring amphipods reflects adaptation to a predator-free environment, this indicates that E. borealis severely weakens its host's anti-predator behavior. Presumably this increases the likelihood of parasite transmission.

  4. Feeding habits of amphipods (Crustacea: Malacostraca) from shallow soft bottom communities: Comparison between marine caves and open habitats

    NASA Astrophysics Data System (ADS)

    Navarro-Barranco, Carlos; Tierno-de-Figueroa, José Manuel; Guerra-García, José Manuel; Sánchez-Tocino, Luis; García-Gómez, José Carlos

    2013-04-01

    Marine caves are environments of great interest since the organisms that inhabit them are forced to develop specific adaptations to high constraint conditions. Because of some of these particular conditions, such as light absence or oligotrophy, it can be expected that feeding strategies into caves differ from that present outside them. Nevertheless, no studies have been done to compare the trophic structure of marine caves and open habitats, at least for amphipod communities, considering their importance both inside and outside of the caves. In this study, the diet of the dominant amphipod species living on shallow sediments, both inside and outside of six marine caves in western Mediterranean, was characterized. Thereby, the gut content of 17 amphipod species was studied, being this study the first attempt to establish the feeding habit of most of these species. Analysis of digestive contents of the species showed that amphipod diet is less diverse in sediments than in other environments, such as algae and seagrasses. No herbivorous species were found in the sediment and carnivorous amphipods showed a little variety of prey, feeding mainly on crustaceans. Differences in the trophic structure were also found between marine caves and open habitats sediments: while outside the caves detritivorous was the dominant group (both in number of species and number of individuals), amphipods mainly play the role of carnivorous inside the caves. No detritivorous species were found into the caves, where carnivorous represents almost 60% of amphipods species and more than 80% of amphipod individuals. This pattern obtained in amphipods differ from the general trend observed in marine cave organisms, for which a generalist diet, such as omnivory, usually is an advantage in these oligotrophic conditions. The possible causes of this pattern are discussed.

  5. Influence of Molting and Starvation on Digestive Enzyme Activities and Energy Storage in Gammarus fossarum

    PubMed Central

    Charron, Laetitia; Geffard, Olivier; Chaumot, Arnaud; Coulaud, Romain; Jaffal, Ali; Gaillet, Véronique; Dedourge-Geffard, Odile; Geffard, Alain

    2014-01-01

    Among the many biological responses studied in ecotoxicology, energy-based biomarkers such as digestive enzyme activities and energy reserves appear to be useful predictive tools for detecting physiological disturbances in organisms. However, the use of these biological responses as biomarkers could be limited by the effects of confounding factors (biotic and abiotic) and physiological processes, such as the reproductive cycle. Thus, the optimal use of these biomarkers will be facilitated by understanding the effects of these factors on the energy metabolism of the sentinel species being studied. We considered abiotic factors (temperature and conductivity) in a previous study, whereas the present study investigated the effects of gender, the female reproductive stage, and food availability on the digestive enzyme activities and energy storage of Gammarus fossarum. The results indicated that, during the female reproductive cycle, the activities of digestive enzymes (amylase, cellulase, and trypsin) decreased significantly, whereas the levels of reserves (proteins, lipids, and sugar) increased until the last premolt stage. Restricted food diets only led to decreased amylase activities in both sexes. Food starvation also induced a decrease in the energy outcomes in females, whereas there were no effects in males. In general, the biochemical (digestive enzyme activities) and physiological (energy reserves) responses were more stable in males than in females. These results support the use of males fed ad libitum to limit the effects of confounding factors when using these energy biomarkers in Gammarus fossarum during biomonitoring programs. PMID:24788197

  6. Aspartic cathepsin D endopeptidase contributes to extracellular digestion in clawed lobsters Homarus americanus and Homarus gammarus.

    PubMed

    Rojo, Liliana; Muhlia-Almazan, Adriana; Saborowski, Reinhard; García-Carreño, Fernando

    2010-11-01

    Acid digestive proteinases were studied in the gastric fluids of two species of clawed lobster (Homarus americanus and Homarus gammarus). An active protein was identified in both species as aspartic proteinase by specific inhibition with pepstatin A. It was confirmed as cathepsin D by mass mapping, N-terminal, and full-length cDNA sequencing. Both lobster species transcribed two cathepsin D mRNAs: cathepsin D1 and cathepsin D2. Cathepsin D1 mRNA was detected only in the midgut gland, suggesting its function as a digestive enzyme. Cathepsin D2 mRNA was found in the midgut gland, gonads, and muscle. The deduced amino acid sequence of cathepsin D1 and cathepsin D2 possesses two catalytic DTG active-site motifs, the hallmark of aspartic proteinases. The putatively active cathepsin D1 has a molecular mass of 36.4 kDa and a calculated pI of 4.14 and possesses three potential glycosylation sites. The sequences showed highest similarities with cathepsin D from insects but also with another crustacean cathepsin D. Cathepsin D1 transcripts were quantified during a starvation period using real-time qPCR. In H. americanus, 15 days of starvation did not cause significant changes, but subsequent feeding caused a 2.5-fold increase. In H. gammarus, starvation caused a 40% reduction in cathepsin D1 mRNA, and no effect was observed with subsequent feeding. PMID:20169386

  7. Growth, feeding frequency, protein turnover, and amino acid metabolism in European lobster Homarus gammarus L.

    PubMed

    Mente, E; Houlihan, D F; Smith, K

    2001-06-01

    The effect of feeding frequency on growth and protein metabolism in the European lobster, Homarus gammarus, was investigated. Fourth (IV) stage lobsters H. gammarus were fed individually a marine animal meal (herring/mussels meal) for 56 days. Feeding a daily ration equivalent to 10% of their body weight gave better growth than feeding daily rations of 5% and 20%. Protein synthesis rates were similar for the three food rations but protein growth rates were significantly lower and protein degradation rates highest in the 5% body weight per day ration group. The efficiency with which synthesised protein was retained as growth was found to be 38% in the in the 10% ratio group. Protein synthesis rates of lobsters were found to be lower than those for shrimps (Penaeus vannamei). The amino acid flux also suggests a lower protein conversion efficiency than shrimps P. vannamei. The results suggests that lobsters are slow, periodic feeders and that growth can be readily increased by manipulation of particular environmental factors such as feeding frequency. PMID:11351329

  8. Male but not female olfaction is crucial for intermolt mating in European lobsters (Homarus gammarus L.).

    PubMed

    Skog, Malin

    2009-02-01

    Chemical signals are common in most crustacean social interactions and are often perceived via chemosensory (olfactory) organs on the first antenna. Intermolt courtship behaviors and mating were investigated in size-matched pairs of intermolt European lobsters (Homarus gammarus) where the olfactory receptors of either the male or the female were lesioned with distilled water (olfactory ablation) or seawater (control). Matings or advanced male courtship behaviors (mounting and turning) were common in seawater controls and olfactory-ablated females. In contrast, when male olfaction was ablated with distilled water, there was not a single mating, and the only male courtship behaviors seen were a few very brief and unsuccessful mounting attempts. Individual females mated up to 5 times with different males, showing that previously inseminated females were still attractive to males. Thus, male but not female olfaction is crucial for intermolt mating in H. gammarus, indicating the presence of a female sex pheromone during the entire female molt cycle, not only at the time of molting. Female sex discrimination may be based on other cues from the male in combination with typical male behaviors. PMID:19073950

  9. Ovary and embryo proteogenomic dataset revealing diversity of vitellogenins in the crustacean Gammarus fossarum.

    PubMed

    Trapp, Judith; Gaillard, Jean-Charles; Chaumot, Arnaud; Geffard, Olivier; Pible, Olivier; Armengaud, Jean

    2016-09-01

    Ovaries and embryos from sexually mature Gammarus fossarum were sampled at different stages of the reproductive cycle. The soluble proteome was extracted for five biological replicates and samples were subjected to trypsin digestion. The resulting peptides were analyzed by high resolution tandem mass spectrometry with a LTQ-Orbitrap XL instrument. The MS/MS spectra were assigned with a previously described RNAseq-derived G. fossarum database. The proteins highlighted by proteogenomics were monitored and their abundance kinetics over the different stages revealed a large panel of vitellogenins. Criteria were i) accumulation during oogenesis, ii) decrease during embryogenesis, iii) classified as female-specific, and iv) sequence similarity and phylogenetic analysis. The data accompanying the manuscript describing the database searches and comparative analysis ("High-throughput proteome dynamics for discovery of key proteins in sentinel species: unsuspected vitellogenins diversity in the crustacean Gammarus fossarum" by Trapp et al. [1]) have been deposited to the ProteomeXchange via the PRIDE repository with identifiers PRIDE: PXD001002. PMID:27547807

  10. A field assessment of long-term laboratory sediment toxicity tests with the amphipod Hyalella azteca

    USGS Publications Warehouse

    Ingersoll, Christopher G.; Wang, Ning; Hayward, Jeannie M. R.; Jones, John R.; Jones, Susan B.; Ireland, D. Scott

    2005-01-01

    Response of the amphipod Hyalella azteca exposed to contaminated sediments for 10 to 42 d in laboratory toxicity tests was compared to responses observed in controlled three-month invertebrate colonization exposures conducted in a pond. Sediments evaluated included a sediment spiked with dichlorodiphenyldichloroethane (DDD) or dilutions of a field sediment collected from the Grand Calumet River (GCR) in Indiana (USA) (contaminated with organic compounds and metals). Consistent effects were observed at the highest exposure concentrations (400 ??g DDD/goc [DDD concentrations normalized to grams of organic carbon (goc) in sedimentl or 4% GCR sediment) on survival, length, and reproduction of amphipods in the laboratory and on abundance of invertebrates colonizing sediments in the field. Effect concentrations for DDD observed for 10-d length and 42-d reproduction of amphipods (e.g., chronic value [ChV] of 66 ??g DDD/goc and 25% inhibition concentration [IC25] of 68 ??g DDD/goc for reproduction) were similar to the lowest effect concentrations for DDD measured on invertebrates colonizing sediment the field. Effect concentrations for GCR sediment on 28-d survival and length and 42-d reproduction and length of amphipods (i.e., ChVs of 0.20-0.66% GCR sediment) provided more conservative effect concentrations compared to 10-d survival or length of amphipods in the laboratory or the response of invertebrates colonizing sediment in the field (e.g., ChVs of 2.2% GCR sediment). Results of this study indicate that use of chronic laboratory toxicity tests with H. azteca and benthic colonization studies should be used to provide conservative estimates of impacts on benthic communities exposed to contaminated sediments. Bioaccumulation of DDD by oligochaetes colonizing the DDD-spiked sediment was similar to results of laboratory sediment tests previously conducted with the oligochaete Lumbriculus variegates, confirming that laboratory exposures can be used to estimate

  11. [Determination of the parameters for producing a biobinder from wood: a mathematical modeling of the transformation of lignocellulose substrate by the fungus Panus tigrinus].

    PubMed

    Kondrashchenko, V I; Manukovskiĭ, N S; Kovalev, V S

    2006-01-01

    A biochemical scheme for the transformation of wood lignocellulose during enzymatic hydrolysis of polysaccharides and lignin destruction in reactions involving free radicals was developed, and a corresponding mathematical model was constructed. Processing (fermentation) of wood particles by the fungus Panus tigrinus in a submerged culture for producing a biobinder of wood composites--woodchip boards and fiber-boards--is considered. The mathematical model was used to study the technological parameters that influence the production of enzymes and fungal biomass and the level of free radical accumulation in the substrate, i.e., the factors determining the production of the biobinder. The optimal values of these parameters were determined, namely: the specific surface of wood particles, amounting to 2000 cm2/g; processing time of 56 h; and an initial concentration of 3.0 g/l of fungal biomass in the submerged culture. PMID:17168304

  12. Change in phospholipid composition and phospholipase activity of the fungus Lentinus tigrinus VKM F-3616D during growth in the presence of phenol and lignocellulosic substrates.

    PubMed

    Kadimaliev, D A; Nadezhina, O S; Parshin, A A; Atykyan, N A; Revin, V V

    2010-11-01

    Changes in phospholipid composition, phospholipase activity, and accumulation of lipid peroxidation products in mycelium of the lignin-degrading fungus Lentinus (Panus) tigrinus VKM F-3616D in the presence of phenol and lignocellulosic substrates in the cultivation medium are reported. It is shown that in fungal mycelium in the presence of both substrates the share of lysophosphatidylcholine sharply increases. The parity between separate groups of phosphatidylinositols also changes. The lysophosphatidylcholine content increase during cultivation is connected with activation of phospholipase A(2) (EC 3.1.1.4), and phosphatidylinositol parity change is associated with distinctions in affinity of phosphoinositide-specific phospholipase C (EC 3.1.4.11) to them. PMID:21314601

  13. Production, purification and partial characterisation of a novel laccase from the white-rot fungus Panus tigrinus CBS 577.79.

    PubMed

    Quaratino, Daniele; Federici, Federico; Petruccioli, Maurizio; Fenice, Massimiliano; D'Annibale, Alessandro

    2007-01-01

    Extracellular laccase from Panus tigrinus CBS 577.79 was produced in a bubble-column reactor using glucose-containing medium supplemented with 2,5-xylidine under conditions of nitrogen sufficiency. The main laccase isoenzyme was purified to apparent homogeneity by ultra-filtration, anion-exchange chromatography and gel filtration that led to a purified enzyme with a specific activity of 317 IU (mg protein)-1 and a final yield of 66%. Laccase was found to be a monomeric protein with a molecular mass of 69.1 kDa, pI of 3.15 and 6.9% N-glycosylation of the high mannose type. Temperature and pH optima were 55 degrees C and 3.75 (2,6-dimethoxyphenol as substrate). At 50 and 60 degrees C, the enzyme half-lives were 281 and 25 min, respectively. The P. tigrinus laccase oxidized a wide range of both naturally occurring and synthetic aromatic compounds: the highest catalytic efficiencies were for 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonic) acid and 2,6-dimethoxyphenol (5.99x10(6) and 3.07x10(6) M-1 s-1, respectively). Catalytic rate constants for typical N-OH redox mediators, such as 1-hydroxybenzotriazole (2.6 s-1), violuric acid (8.4 s-1) and 2,2,6,6-tetramethylpiperidin-N-oxide radical (7.8 s-1), were found to be higher than those reported for other high redox potential fungal laccases. PMID:17013550

  14. Kinetic and redox properties of MnP II, a major manganese peroxidase isoenzyme from Panus tigrinus CBS 577.79.

    PubMed

    Petruccioli, Maurizio; Frasconi, Marco; Quaratino, Daniele; Covino, Stefano; Favero, Gabriele; Mazzei, Franco; Federici, Federico; D'Annibale, Alessandro

    2009-11-01

    A manganese peroxidase (MnP) isoenzyme from Panus tigrinus CBS 577.79 was produced in a benchtop stirred-tank reactor and purified to apparent homogeneity. The purification scheme involving ultrafiltration, affinity chromatography on concanavalin-A Sepharose, and gel filtration led to a purified MnP, termed "MnP II," with a specific activity of 288 IU mg(-1) protein and a final yield of 22%. The enzyme turned out to be a monomeric protein with molecular mass of 50.5 kDa, pI of 4.07, and an extent of N-glycosylation of about 5.3% of the high-mannose type. The temperature and pH optima for the formation of malonate manganic chelates were 45 degrees C and 5.5, respectively. MnP II proved to be poorly thermostable at 50 and 60 degrees C, with half-lives of 11 min and 105 s, respectively. K (m) values for H(2)O(2) and Mn(2+) were 16 and 124 microM, respectively. Although MnP II was able to oxidize veratryl alcohol and to catalyze the Mn(2+)-independent oxidation of several phenols, it cannot be assigned to the versatile peroxidase family. As opposed to versatile peroxidase oxidation, veratryl alcohol oxidation required the simultaneous presence of H(2)O(2) and Mn(2+); in addition, low turnover numbers and K (m) values higher than 300 microM characterized the Mn(2+)-independent oxidation of substituted phenols. Kinetic properties and the substrate specificity of the enzyme markedly differed from those reported for MnP isoenzymes produced by the reference strain P. tigrinus 8/18. To our knowledge, this study reports for the first time a thorough electrochemical characterization of a MnP from this fungus. PMID:19578878

  15. Effects of water hardness, water temperature, and size of the test organism on the susceptibility of the freshwater shrimp, Gammarus pulex (L. ), to toxicants

    SciTech Connect

    Stephenson, R.R.

    1983-10-01

    In this study the authors examined the effects of water hardness, water temperature, size of test organism and duration of exposure on the acute toxicity of four substances to Gammarus pulex (L.), the freshwater shrimp.

  16. Effects of light pollution on the emergent fauna of shallow marine ecosystems: Amphipods as a case study.

    PubMed

    Navarro-Barranco, Carlos; Hughes, Lauren Elizabeth

    2015-05-15

    Light pollution from coastal urban development is a widespread and increasing threat to biodiversity. Many amphipod species migrate between the benthos and the pelagic environment and light seems is a main ecological factor which regulates migration. We explore the effect of artificial lighting on amphipod assemblages using two kind of lights, LED and halogen, and control traps in shallow waters of the Great Barrier Reef. Both types of artificial light traps showed a significantly higher abundance of individuals for all species in comparison to control traps. LED lights showed a stronger effect over the amphipod assemblages, with these traps collecting a higher number of individuals and differing species composition, with some species showing a specific attraction to LED light. As emergent amphipods are a key ecological group in the shallow water environment, the impact of artificial light can affect the broader functioning of the ecosystem.

  17. Avoidance response of the estuarine amphipod Eohaustorius estuarius to polycyclic aromatic hydrocarbon-contaminated, field-collected sediments

    SciTech Connect

    Kravitz, M.J. . Office of Water); Lamberson, J.O.; Ferraro, S.P.; Swartz, R.C.; Boese, B.L.; Specht, D.T. )

    1999-06-01

    Amphipods (Eohaustorius estuarius) were placed in two-chamber containers with different combinations of three contaminated sediments and a control sediment, and their distribution was determined after 2 or 3 d. Amphipods avoided the sediment with the highest PAH contamination and one of two sediments with moderate PAH concentrations. In the moderately contaminated sediment avoided by amphipods, the (avoidance) response was more sensitive than mortality as a biological indicator of unacceptable sediment contamination. The avoidance response in this case likely represents an early indication of potential mortality from sediment exposure. Population levels of amphipods in moderately to heavily PAH-contaminated sediments may be influenced by a combination of avoidance behavior and toxicity/lethality.

  18. Relationships among levels of benthic vegetation and pore-water sulfides, burrowing shrimp and infaunal amphipods in Yaquina estuary, Oregon

    EPA Science Inventory

    Benthic amphipods are an important component of estuarine food webs, which in turn support ecological services provided by near shore commercial and recreational fisheries. In this study relationships among biological and geochemical aspects of the intertidal community were inve...

  19. Acute toxicity and biochemical effects of azinphos methyl in the amphipod Hyalella curvispina.

    PubMed

    Anguiano, Olga Liliana; Castro, Claudia; Venturino, Andrés; Ferrari, Ana

    2014-09-01

    We evaluated the acute toxicity and biochemical effects of the organophosphorus pesticide azinphos methyl (AM) in the amphipod Hyalella curvispina that inhabits ponds and irrigation channels of an intensive fruit-producing region in Rio Negro and Neuquén valley, North Patagonia, Argentina. The analysis by nonlinear regression of data from the 96 h-acute toxicity tests indicated the coexistence of two subpopulations of H. curvispina with different susceptibilities to AM. The 96 h-LC₅₀ for the resistant subpopulation (166 ± 56 μg/L) was 216-fold higher than the 96h-LC₅₀ value for the susceptible one (0.77 ± 1.33 μg/L).The two subpopulations could not be distinguished based on the biochemical measurements in control amphipods. Cholinesterase activity was significantly inhibited in AM-exposed amphipods in a concentration-dependent manner. The IC₅₀ value obtained after 96 h of exposure (2.18 ± 1.95 μg/L) was significantly lower than the 48 h-IC₅₀ value (29.6 ± 17.4 μg/L). Carboxylesterase activity was significantly inhibited after 48 h of exposure to 12.5 and 62.5 μg/L AM (inhibition, 51%). This enzyme was thus able to protect cholinesterase from inhibition at 12.5 μg/L AM. Reduced glutathione and catalase showed a significant increase after 24 h of exposure as an adaptive response to AM, whereas glutathione S-transferase activity was not significantly modified. The analysis of species sensitivity distribution showed that both subpopulations of H. curvispina were more tolerant to AM than most amphipod species, and that the susceptible subpopulation was more sensitive to AM than the other local aquatic species analyzed. The maximum concentration of AM in drainage water within the fruit-producing area reported by other studies would affect most of the amphipod species (99%) and also a 44% of local aquatic ones. The results obtained in this study point out the usefulness of including amphipods like H. curvispina in ecotoxicity studies and

  20. Nutritional quality of the edible tissues of European lobster Homarus gammarus and American lobster Homarus americanus.

    PubMed

    Barrento, Sara; Marques, António; Teixeira, Bárbara; Vaz-Pires, Paulo; Nunes, Maria Leonor

    2009-05-13

    The clawed lobsters Homarus gammarus and Homarus americanus are high-priced and appreciated food items in southern Europe. From a nutritional point of view there is still limited information on the chemical composition of edible tissues (muscle, hepatopancreas, and gonads) of both species. Therefore, the aims of the present work were to study the proximate chemical composition, energy, fatty acid and amino acid profiles, and cholesterol content in each edible tissue of both species and to evaluate their nutritional quality. Differences were observed between tissues, sexes, and species. Muscle and gonads were rich in protein, whereas hepatopancreas had high fat, cholesterol, and energy contents. All edible tissues were valuable sources of essential amino acids. Contrary to the common belief that shellfish consumption should be reduced in a low-fat and -cholesterol diet, all edible tissues of clawed lobsters have a nutritious value perfectly compatible with nutritious and healthy diets. PMID:19334784

  1. Silver nanoparticles impact the functional role of Gammarus roeseli (Crustacea Amphipoda).

    PubMed

    Andreï, Jennifer; Pain-Devin, Sandrine; Felten, Vincent; Devin, Simon; Giambérini, Laure; Mehennaoui, Kahina; Cambier, Sebastien; Gutleb, Arno C; Guérold, François

    2016-01-01

    Silver nanoparticles (nAg) are widely used in consumer products and the risk associated with their potential release into freshwater ecosystems needs to be addressed using environmentally realistic exposure concentrations. Here, the effects of low concentrations (0.5-5 μg L(-1)) of two different sized nAg (10 and 60 nm) and a silver nitrate positive control were evaluated in Gammarus roeseli following exposure for 72 h. Cellular, individual and functional endpoints were independently studied and the most striking results were reported for functional endpoints. Indeed, without a change in their feeding activity, the gammarids produced significantly fewer fine particles of organic matter when exposed to nAg, even at 0.5 μg L(-1) of 10 nm nAg. These functional endpoints seem to be efficient markers for detecting the early effects of nAg on G. roeseli. PMID:26552543

  2. Sediment toxicity to a marine infaunal amphipod: cadmium and its interaction with sewage sludge

    SciTech Connect

    Swartz, R.C.; Ditsworth, G.R.; Schults, D.W.; Lamberson, J.O.

    1985-01-01

    The acute toxicity of cadmium to the marine infaunal amphipod, Rhepoxynius abronius, was determined separately in sediment and seawater. Most cadmium added to test sediment was bound to particles and less than 5% was dissolved in interstitial water. The LC50 based on cadmium concentration in interstitial water was similar to the LC50 based on cadmium concentration in seawater without sediment. Cadmium in interstitial water, rather than that bound to particles, therefore appears responsible for acute sediment toxicity to this species. The addition of small quantities of sewage sludge or an increase in the proportion of the fine fraction of sediment particles significantly reduced the toxicity of cadmium in sediment. Binding of cadmium by sediment particles may explain the presence of phoxocephalid amphipods at sites where sewage and metal pollution occur together.

  3. Influence of bromide on the performance of the amphipod Hyalella azteca in reconstituted waters

    USGS Publications Warehouse

    Ivey, Chris D.; Ingersoll, Christopher G.

    2016-01-01

    Poor performance of the amphipod Hyalella azteca has been observed in exposures using reconstituted waters. Previous studies have reported success in H. azteca water-only exposures with the addition of relatively high concentrations of bromide. The present study evaluated the influence of lower environmentally representative concentrations of bromide on the response ofH. azteca in 42-d water-only exposures. Improved performance of H. azteca was observed in reconstituted waters with >0.02 mg Br/L.

  4. Acoustic and in situ measurements of freshwater amphipods (Jesogammarus annandalei) in Lake Biwa, Japan

    SciTech Connect

    Trevorrow, M.V.; Tanaka, Yuji

    1997-01-01

    During a 23-d study of Lake Biwa, Japan (starting 23 August 1993), multifrequency inverted echo-sounder measurements of nocturnal scattering layers in the meta- and epilimnion were performed at a single location. Direct samples from within this scattering layer indicated that it was composed of Jesogammarus annandalei (Crustacea:Amphipoda), with mean adult length of 8.3 mm and population densities from 4 to 50 per m{sup 3}. Estimates of the scattering cross-section for individual amphipods were extracted from echo-amplitude probability distributions combined with volume scattering strength from a 198-kHz sonar. Total scattering cross-sections for adult amphipods at 88, 118, and 198 kHz were estimated as 4.3{plus_minus}0.9 x 10{sup {minus}8} m{sup 2}, 8.7{plus_minus}1.2 x 10{sup {minus}8} m{sup 2}, and 2.8{plus_minus}0.5 x 10{sup {minus}7} m{sup 2}. These cross-section measurements were found to be consistent with a fluid cylinder acoustic scattering model with a 1.2-mm radius and a 9.6-mm length. The acoustically derived population densities, sizes, and length-to-radius ratio were consistent with in situ amphipod samples. The amphipods exhibited a clear nocturnal migration into the lower thermocline, concentrating at depths of 15-25 m beginning after sunset (near 1830 hours local time) each day. Population densities (10-min averaged) showed maxima of 10-30 per m{sup 3} near 2000 hours, with densities decreasing rapidly toward midnight and disappearing by approximately 0430 hours. 23 refs., 11 figs., 2 tabs.

  5. Light triggers habitat choice of eyeless subterranean but not of eyed surface amphipods.

    PubMed

    Fišer, Žiga; Novak, Luka; Luštrik, Roman; Fišer, Cene

    2016-02-01

    Boundaries of species distributions are the result of colonization-extinction processes. Survival on the boundary depends on how well individuals discriminate optimal from suboptimal habitat patches. Such behaviour is called habitat choice and was only rarely applied to macroecology, although it links species ecological niche and species distribution. Surface and subterranean aquatic species are spatially strongly segregated, even in the absence of physical barriers. We explored whether a behavioural response to light functions as a habitat choice mechanism that could explain species turnover between surface and subterranean aquatic ecosystems. In a controlled laboratory experiment, we studied the behavioural response to light of ten pairs of surface and subterranean amphipods that permanently co-occur in springs. Surface species showed a weak photophobic, photoneutral, and in one case, photophilic response, whereas all subterranean species showed a strong photophobic response. Eyeless subterranean but not eyed surface amphipods appear to orient themselves with light cues. On a local scale, this difference possibly diminishes harmful interactions between the co-occurring amphipods, whereas on a regional scale, photophobia could explain limited dispersal and a high degree of endemism observed among subterranean species. PMID:26757929

  6. A preliminary study of the Caprella scaura amphipod culture for potential use in aquaculture

    NASA Astrophysics Data System (ADS)

    Baeza-Rojano, Elena; Calero-Cano, Sandra; Hachero-Cruzado, Ismael; Guerra-García, José Manuel

    2013-10-01

    The caprellid amphipod Caprella scaura Templeton, 1836 was investigated as a mass culture organism, for potential use as natural prey in aquaculture. C. scaura showed good population growth during 3 months of culturing with nauplii of Artemia sp. and microalgae as food source. A final mean population size of 12,510.67 individuals/tank and a maximum density of 10,460 individuals m- 2 were obtained; a 50-fold increase of the initial population was observed. Juveniles were the most abundant stage in the culture (86.0% of total), followed by mature females (5.4%) and immature males (3.1%). Three kinds of plastic mesh with different complexity levels were used as artificial substrates for amphipods to attach to and shelter. There were no significant differences in the total number of individuals present on each kind of mesh, although female and male adults were more abundant in folded meshes with larger pore diameter. This research demonstrated that the caprellid amphipod C. scaura may be readily cultured at high densities with a variety of mesh morphologies allowing more efficient use of tank volume and improved handling.

  7. Use of sublethal endpoints in sediment toxicity testing with the amphipod Hyalella azteca

    SciTech Connect

    Kemble, N.E.; Brunson, E.B.; Dwyer, F.J.; Ehrhardt, E.A.; Hardesty, D.K.; Haverland, P.S.; Ingersoll, C.G.

    1995-12-31

    ASTM and EPA standard methods for sediment toxicity tests with Hyalella azteca typically recommend use of lethality as the endpoint in a 10-d exposure. However, data from 10- to 28-d exposures with amphipods indicate sublethal endpoints (i.e., growth, sexual maturation, or reproduction) identify additional samples as toxic. The authors compared the frequency that lethal and sublethal endpoints identified a sediment sample as toxic in 14- and 28-d amphipod exposures. In the 14-d amphipod exposures, lethality identified 20% of the samples as toxic, and sublethal endpoints identified an additional 16% of the samples as toxic using sublethal endpoints only. Similarly, in the 28-d exposures, lethality identified 14% of the samples as toxic and sublethal endpoints identified an additional 18% of the samples as toxic. The authors are also currently evaluating Sediment Effect Concentrations (SECs) relative to both lethal and sublethal endpoints in H. azteca exposures. These SECs will be used to evaluate reliability in estimating toxicity of samples. Potential factors which may confound interpretation of sublethal endpoints in sediment tests include: (1) changes in sediment chemistry resulting from long-term storage or feeding (2) the influence of physical characteristics of sediment (grain size), and (3) effects of ammonia or hydrogen sulfide.

  8. The use of carbon resin for the reduction of sediment toxicity to infaunal amphipods

    SciTech Connect

    Hurk, P. van den; Vogelbein, M.A.; McCullough, D.; Roberts, M.H. Jr.

    1995-12-31

    Commercially available carbon resins are designed to absorb non-polar organic compounds. To evaluate the potential of resins to absorb hydrophobic pore water pollutants and thus reduce the toxicity of sediments the Ambersorb 1500 resin was mixed with PAH-contaminated sediment samples and tested with infaunal amphipods. The sediments were collected at a freshwater site in the Little Scioto River, OH and at an estuarine site in the Elisabeth River, VA. The bulk chemical analysis of both sediments was comparable in that they both show creosote pollution. The sediments were tested in dilution series with clean reference sediments and with increasing amounts of resin (2, 4 and 8% dry sediment weight). The freshwater sediments were tested with both Hyalella azteca (a freshwater infaunal amphipod) and Leptocheirus plumulosus (an estuarine infaunal amphipod). The estuarine sediments were only tested with L. plumulosus. Significant effects of the resin were recognized by comparing polluted sediment LC50s with their 95% confidence intervals, as calculated with the Trimmed Spearman-Karber test. The results show that the freshwater samples were not very toxic to either of the species (LC50: 80--100% polluted sediment), and there was no significant effect of the resin. The estuarine samples were highly toxic (LC50: 3--13% polluted sediment) and there was a significant reduction of toxicity with increasing amount of resin. Pore water chemical analysis will be evaluated to explain the toxicity differences between the freshwater and estuarine samples.

  9. Assessing estuarine quality: A cost-effective in situ assay with amphipods.

    PubMed

    Martinez-Haro, Monica; Acevedo, Pelayo; Pais-Costa, Antónia Juliana; Taggart, Mark A; Martins, Irene; Ribeiro, Rui; Marques, João Carlos

    2016-05-01

    In situ assays based on feeding depression can be powerful ecotoxicological tools that can link physiological organism-level responses to population and/or community-level effects. Amphipods are traditional target species for toxicity tests due to their high sensitivity to contaminants, availability in the field and ease of handling. However, cost-effective in situ assays based on feeding depression are not yet available for amphipods that inhabit estuarine ecosystems. The aim of this work was to assess a short-term in situ assay based on postexposure feeding rates on easily quantifiable food items with an estuarine amphipod. Experiments were carried out under laboratory conditions using juvenile Echinogammarus marinus as the target individual. When 60 Artemia franciscana nauplii (as prey) were provided per individual for a period of 30 min in dark conditions, feeding rates could be easily quantified. As an endpoint, postexposure feeding inhibition in E. marinus was more sensitive to cadmium contamination than mortality. Assay calibration under field conditions demonstrated the relevance of sediment particle size in explaining individual feeding rates in uncontaminated water bodies. An evaluation of the 48-h in situ bioassay based on postexposure feeding rates indicated that it is able to discriminate between unpolluted and polluted estuarine sites. Using the harmonized protocol described here, the in situ postexposure feeding assay with E. marinus was found to be a potentially useful, cost-effective tool for assessing estuarine sediment and water quality.

  10. Light triggers habitat choice of eyeless subterranean but not of eyed surface amphipods.

    PubMed

    Fišer, Žiga; Novak, Luka; Luštrik, Roman; Fišer, Cene

    2016-02-01

    Boundaries of species distributions are the result of colonization-extinction processes. Survival on the boundary depends on how well individuals discriminate optimal from suboptimal habitat patches. Such behaviour is called habitat choice and was only rarely applied to macroecology, although it links species ecological niche and species distribution. Surface and subterranean aquatic species are spatially strongly segregated, even in the absence of physical barriers. We explored whether a behavioural response to light functions as a habitat choice mechanism that could explain species turnover between surface and subterranean aquatic ecosystems. In a controlled laboratory experiment, we studied the behavioural response to light of ten pairs of surface and subterranean amphipods that permanently co-occur in springs. Surface species showed a weak photophobic, photoneutral, and in one case, photophilic response, whereas all subterranean species showed a strong photophobic response. Eyeless subterranean but not eyed surface amphipods appear to orient themselves with light cues. On a local scale, this difference possibly diminishes harmful interactions between the co-occurring amphipods, whereas on a regional scale, photophobia could explain limited dispersal and a high degree of endemism observed among subterranean species.

  11. Effect of salinity on the toxicity of road dust in an estuarine amphipod Grandidierella japonica.

    PubMed

    Hiki, Kyoshiro; Nakajima, Fumiyuki

    2015-01-01

    Urban runoff can reach coastal aquatic environments; however, little is known about the effect of salinity on road runoff toxicity. The objective of this study is to investigate the toxicity of highway road dust over a salinity gradient from 5 to 35‰, in an estuarine benthic amphipod, Grandidierella japonica. Road dust toxicity was evaluated by assessing mortality after 10 days of exposure and short-term microbead ingestion activity of the amphipod. For all road dust samples considered, amphipod mortality increased with increasing salinity, whereas no significant difference in mortality was observed among test salinities in the reference river sediment. Ingestion activity during exposure to road dust decreased with increasing salinity. In fact, none of the individuals ingested any microbeads at salinity of 35‰. If assumed microbead ingestion is a proxy for feeding activity, high mortality at 35‰ could be attributed to aquatic exposure and not to dietary exposure. These findings suggest that road dust may have considerable impact on benthic organisms at high salinity levels. PMID:26360764

  12. AxIOM: Amphipod crustaceans from insular Posidonia oceanica seagrass meadows

    PubMed Central

    Heughebaert, André; Lepoint, Gilles

    2016-01-01

    Abstract Background The Neptune grass, Posidonia oceanica (L.) Delile, 1813, is the most widespread seagrass of the Mediterranean Sea. This foundation species forms large meadows that, through habitat and trophic services, act as biodiversity hotspots. In Neptune grass meadows, amphipod crustaceans are one of the dominant groups of vagile invertebrates, forming an abundant and diverse taxocenosis. They are key ecological components of the complex, pivotal, yet critically endangered Neptune grass ecosystems. Nevertheless, comprehensive qualitative and quantitative data about amphipod fauna found in Mediterranean Neptune grass meadows remain scarce, especially in insular locations. New information Here, we provide in-depth metadata about AxIOM, a sample-based dataset published on the GBIF portal. AxIOM is based on an extensive and spatially hierarchized sampling design with multiple years, seasons, day periods, and methods. Samples were taken along the coasts of Calvi Bay (Corsica, France) and of the Tavolara-Punta Coda Cavallo Marine Protected Area (Sardinia, Italy). In total, AxIOM contains 187 samples documenting occurrence (1775 records) and abundance (10720 specimens) of amphipod crustaceans belonging to 72 species spanning 29 families. The dataset is available at http://ipt.biodiversity.be/resource?r=axiom. PMID:27660521

  13. AxIOM: Amphipod crustaceans from insular Posidonia oceanica seagrass meadows

    PubMed Central

    Heughebaert, André; Lepoint, Gilles

    2016-01-01

    Abstract Background The Neptune grass, Posidonia oceanica (L.) Delile, 1813, is the most widespread seagrass of the Mediterranean Sea. This foundation species forms large meadows that, through habitat and trophic services, act as biodiversity hotspots. In Neptune grass meadows, amphipod crustaceans are one of the dominant groups of vagile invertebrates, forming an abundant and diverse taxocenosis. They are key ecological components of the complex, pivotal, yet critically endangered Neptune grass ecosystems. Nevertheless, comprehensive qualitative and quantitative data about amphipod fauna found in Mediterranean Neptune grass meadows remain scarce, especially in insular locations. New information Here, we provide in-depth metadata about AxIOM, a sample-based dataset published on the GBIF portal. AxIOM is based on an extensive and spatially hierarchized sampling design with multiple years, seasons, day periods, and methods. Samples were taken along the coasts of Calvi Bay (Corsica, France) and of the Tavolara-Punta Coda Cavallo Marine Protected Area (Sardinia, Italy). In total, AxIOM contains 187 samples documenting occurrence (1775 records) and abundance (10720 specimens) of amphipod crustaceans belonging to 72 species spanning 29 families. The dataset is available at http://ipt.biodiversity.be/resource?r=axiom.

  14. Effect of salinity on the toxicity of road dust in an estuarine amphipod Grandidierella japonica.

    PubMed

    Hiki, Kyoshiro; Nakajima, Fumiyuki

    2015-01-01

    Urban runoff can reach coastal aquatic environments; however, little is known about the effect of salinity on road runoff toxicity. The objective of this study is to investigate the toxicity of highway road dust over a salinity gradient from 5 to 35‰, in an estuarine benthic amphipod, Grandidierella japonica. Road dust toxicity was evaluated by assessing mortality after 10 days of exposure and short-term microbead ingestion activity of the amphipod. For all road dust samples considered, amphipod mortality increased with increasing salinity, whereas no significant difference in mortality was observed among test salinities in the reference river sediment. Ingestion activity during exposure to road dust decreased with increasing salinity. In fact, none of the individuals ingested any microbeads at salinity of 35‰. If assumed microbead ingestion is a proxy for feeding activity, high mortality at 35‰ could be attributed to aquatic exposure and not to dietary exposure. These findings suggest that road dust may have considerable impact on benthic organisms at high salinity levels.

  15. Assessing estuarine quality: A cost-effective in situ assay with amphipods.

    PubMed

    Martinez-Haro, Monica; Acevedo, Pelayo; Pais-Costa, Antónia Juliana; Taggart, Mark A; Martins, Irene; Ribeiro, Rui; Marques, João Carlos

    2016-05-01

    In situ assays based on feeding depression can be powerful ecotoxicological tools that can link physiological organism-level responses to population and/or community-level effects. Amphipods are traditional target species for toxicity tests due to their high sensitivity to contaminants, availability in the field and ease of handling. However, cost-effective in situ assays based on feeding depression are not yet available for amphipods that inhabit estuarine ecosystems. The aim of this work was to assess a short-term in situ assay based on postexposure feeding rates on easily quantifiable food items with an estuarine amphipod. Experiments were carried out under laboratory conditions using juvenile Echinogammarus marinus as the target individual. When 60 Artemia franciscana nauplii (as prey) were provided per individual for a period of 30 min in dark conditions, feeding rates could be easily quantified. As an endpoint, postexposure feeding inhibition in E. marinus was more sensitive to cadmium contamination than mortality. Assay calibration under field conditions demonstrated the relevance of sediment particle size in explaining individual feeding rates in uncontaminated water bodies. An evaluation of the 48-h in situ bioassay based on postexposure feeding rates indicated that it is able to discriminate between unpolluted and polluted estuarine sites. Using the harmonized protocol described here, the in situ postexposure feeding assay with E. marinus was found to be a potentially useful, cost-effective tool for assessing estuarine sediment and water quality. PMID:26874320

  16. Phylogenetic relationships among hadal amphipods of the Superfamily Lysianassoidea: Implications for taxonomy and biogeography

    NASA Astrophysics Data System (ADS)

    Ritchie, H.; Jamieson, A. J.; Piertney, S. B.

    2015-11-01

    Amphipods of the superfamily Lysianassoidea are ubiquitous at hadal depths (>6000 m) and therefore are an ideal model group for investigating levels of endemism and the drivers of speciation in deep ocean trenches. The taxonomic classification of hadal amphipods is typically based on conventional morphological traits but it has been suggested that convergent evolution, phenotypic plasticity, intra-specific variability and ontogenetic variation may obscure the ability to robustly diagnose taxa and define species. Here we use phylogenetic analysis of DNA sequence variation at two mitochondrial (COI and 16S rDNA) and one nuclear (18S rDNA) regions at to examine the evolutionary relationships among 25 putative amphipod species representing 14 genera and 11 families that were sampled from across seven hadal trenches. We identify several instances where species, genera and families do not resolve monophyletic clades, highlighting incongruence between the current taxonomic classification and the molecular phylogeny for this group. Our data also help extend and resolve the known biogeographic distributions for the different species, such as identifying the co-occurrence of Hirondellea dubia and Hirondellea gigas in the Mariana trench.

  17. The Source of Bacteria Involved in the Break-Down of Gammarus Pulex Faecal Pellets Using Image Analysis

    NASA Astrophysics Data System (ADS)

    Joyce, P.; Wotton, R.

    2005-05-01

    Bacteria survive passage through the gut of aquatic animals and are implicated in the break-down of POM (such as faecal pellets) in aquatic systems. There is evidence that bacteria that survive gut passage are the cause of the initial break-down of faecal pellets, rather than colonisation by bacteria from the environment. Gammarus is the dominant shredder in lowland permeable catchments ("chalk streams") in England and feeds on allochthonous detritus such as fallen leaves. Gammarus faecal pellets could form important pathways for transfer of organic matter in chalk streams. We incubated Gammarus faecal pellets for 80 days in stream water using combinations of treatments (autoclaving the stream water or pellets; fresh non-autoclaved stream water or pellets; reducing bacterial activity using Gentamicin; combinations of these treatments) to assess the role of surviving and colonising bacteria on the break-down process. Break-down was measured using image analysis. Results show that treatments with fresh pellets show much higher levels of break-down than fully autoclaved controls, treatments with fresh stream water but autoclaved pellets, or treatments with Gentamicin. Bacteria surviving gut passage therefore seem to play a greater role in faecal pellet break-down than those colonising from the environment.

  18. Effects of sediment characteristics on the toxicity of chromium(III) and chromium(VI) to the amphipod, Hyalella azteca

    USGS Publications Warehouse

    Besser, J.M.; Brumbaugh, W.G.; Kemble, N.E.; May, T.W.; Ingersoll, C.G.

    2004-01-01

    We evaluated the influence of sediment characteristics, acid-volatile sulfide (AVS) and organic matter (OM), on the toxicity of chromium (Cr) in freshwater sediments. We conducted chronic (28-42-d) toxicity tests with the amphipod Hyalella azteca exposed to Cr(VI) and Cr(III) in water and in spiked sediments. Waterborne Cr(VI) caused reduced survival of amphipods with a median lethal concentration (LC50) of 40 ??g/L. Cr(VI) spiked into test sediments with differing levels of AVS resulted in graded decreases in AVS and sediment OM. Only Cr(VI)-spiked sediments with low AVS concentrations (<1 ??mol/g) caused significant amphipod mortality. Waterborne Cr(III) concentrations near solubility limits caused decreased survival of amphipods at pH 7 and pH 8 but not at pH 6. Sediments spiked with high levels of Cr(III) did not affect amphipod survival but had minor effects on growth and inconsistent effects on reproduction. Pore waters of some Cr(III)-spiked sediments contained measurable concentrations of Cr(VI), but observed toxic effects did not correspond closely to Cr concentrations in sediment or pore waters. Our results indicate that risks of Cr toxicity are low in freshwater sediments containing substantial concentrations of AVS.

  19. Review of the reproductive biology of amphipods and their endocrine regulation: identification of mechanistic pathways for reproductive toxicants.

    PubMed

    Hyne, Ross V

    2011-12-01

    The reproductive biology of amphipods is reviewed to update the knowledge of the male and female reproductive processes of oogenesis and spermatogenesis as well as the endocrine systems of amphipods with the aim of advancing studies of reproductive toxicology. The ovarian and reproduction cycles of female gammaridean amphipods are closely correlated with the molt cycle, which is under direct control by the steroid hormone 20-hydroxyecdysone. The ability of males to copulate and subsequently for females to ovulate is restricted to the early postmolt period of the females. New developments in our understanding of the molt cycle and the endocrine regulatory pathways for reproduction using genomics techniques on other crustacean species are also discussed. The arthropod sterol ponasterone A or xenobiotics such as the fungicide fenarimol have been shown to elicit endocrine disruption in some crustaceans by acting as an agonist for 20-hydroxyecdysone at the ecdysone receptor or by inhibiting the synthesis of 20-hydroxyecdysone, respectively, resulting in disruption of molting and reproduction. Recent studies suggest that cadmium can inhibit secondary vitellogenesis in amphipods. Experimental approaches for examining the metabolic pathways associated with ecdysteroid hormonal signaling or metabolism, exoskeleton maintenance and molting, and the regulation of vitellogenin in amphipods are discussed. This information should aid in the identification of useful biomarkers for reproductive toxicity.

  20. A comparison of in situ and laboratory toxicity tests with the estuarine amphipod Eohaustorius estuarius.

    PubMed

    Anderson, B S; Hunt, J W; Phillips, B M; Nicely, P A; Tjeerdema, R S; Martin, M

    2004-01-01

    Amphipod survival in laboratory and in situ exposures was assessed using the eastern Pacific Haustoriid species Eohaustorius estuarius. Toxicity test results were compared using intact (unhomogenized) and homogenized sediment samples in both field and laboratory exposures. Experiments were conducted in Moss Landing Harbor, California, an impaired waterbody under 303 (d) of the US Clean Water Act. Synoptic laboratory and in situ sediment toxicity tests were conducted at two stations: Sandholdt Bridge (SB), the most contaminated station in the harbor, and at the South Jetty (SJ), a more marine station near the mouth of the harbor. We found that Eohaustorius is amenable to in situ testing. Despite highly variable field salinity regimes (6-32 PSU at SB and 21-34 PSU at SJ), in situ control survival was 87% and 84% at SB and SJ, respectively. Amphipod survival was lower in the in situ exposures relative to the laboratory exposures at both sites. Survival at SB was 30% and 76% in the homogenized in situ and laboratory samples, respectively, and 40% and 64% in the intact (unhomogenized) in situ and laboratory samples, respectively. Neither the homogenized or intact samples from the SJ station were toxic in laboratory experiments, but amphipod survival was only 40% in the intact in situ exposure at this station, possibly due to predation. These experiments suggest that the interaction of contaminants and variable physical parameters such as salinity and temperature may have resulted in lower survival in the in situ exposures. Sediment homogenization prior to in situ deployment may have reduced effects of predators in some samples. PMID:15025164

  1. Amphipod sediment bioassays: effects on response of methodology, grain size, organic content, and cadmium

    SciTech Connect

    Ott, F.S.

    1986-01-01

    Ten day sediment bioassays and behavioral tests were conducted with the phoxocephalid amphipod Rhepoxynius abronius to determine individual and interactive effects on response of grain size, cadmium (Cd), and organic content in static and flow-through systems. Effects of freezing sediment and variations in animal sensitivity (due to age and season) were also examined. In addition, bioassays were conducted biannually over a 2-yr period using sediments from 27 stations in central Puget Sound, Washington. Sterile sediments with a mean grain size <29-54 um were acutely toxic to amphipods. The 96-h LC50 for water-borne Cd was 1.7 ppm; the 10-day LC50 for Cd in native sand was 8.8 ppm. Toxicity from Cd and tissue Cd uptake were a direct function of the seawater Cd concentration which decreased with decreasing grain size and increasing organic content. Therefore, Cd bioavailability was not correlated with total Cd in sediment. Survival was similar or lower in a static versus a flow-through system with the magnitude of the difference in response between systems being greatest in contaminated fine-grain sediments. Amphipods were more sensitive during Jan-March then Oct-Nov. Shifts in sensitivity may be related to the recruitment/growth pattern and the overwintering habits of this animal. In bioassays conducted with field sediments, geographic patterns of sediment toxicity were apparent. Survival was negatively correlated with mean grain size and priority pollutant load of 15 heavy metals and 50 organic compounds, although response could not be attributed to any single parameter.

  2. Toxicity of sediment cores collected from the ashtabula river in northeastern Ohio, USA, to the amphipod hyalella azteca

    USGS Publications Warehouse

    Ingersoll, C.G.; Kemble, N.E.; Kunz, J.L.; Brumbaugh, W.G.; MacDonald, D.D.; Smorong, D.

    2009-01-01

    This study was conducted to support a Natural Resource Damage Assessment and Restoration project associated with the Ashtabula River in Ohio. The objective of the study was to evaluate the chemistry and toxicity of 50 sediment samples obtained from five cores collected from the Ashtabula River (10 samples/core, with each 10-cm-diameter core collected to a total depth of about 150 cm). Effects of chemicals of potential concern (COPCs) measured in the sediment samples were evaluated by measuring whole-sediment chemistry and whole-sediment toxicity in the sediment samples (including polycyclic aromatic hydrocarbons [PAHs], polychlorinated biphenyls [PCBs], organochlorine pesticides, and metals). Effects on the amphipod Hyalella azteca at the end of a 28-day sediment toxicity test were determined by comparing survival or length of amphipods in individual sediment samples in the cores to the range of responses of amphipods exposed to selected reference sediments that were also collected from the cores. Mean survival or length of amphipods was below the lower limit of the reference envelope in 56% of the sediment samples. Concentrations of total PCBs alone in some samples or concentrations of total PAHs alone in other samples were likely high enough to have caused the reduced survival or length of amphipods (i.e., concentrations of PAHs or PCBs exceeded mechanistically based and empirically based sediment quality guidelines). While elevated concentrations of ammonia in pore water may have contributed to the reduced length of amphipods, it is unlikely that the reduced length was caused solely by elevated ammonia (i.e., concentrations of ammonia were not significantly correlated with the concentrations of PCBs or PAHs and concentrations of ammonia were elevated both in the reference sediments and in the test sediments). Results of this study show that PAHs, PCBs, and ammonia are the primary COPCs that are likely causing or substantially contributing to the toxicity to

  3. Sensitivities of Australian and New Zealand amphipods to copper and zinc in waters and metal-spiked sediments.

    PubMed

    King, Catherine K; Gale, Sharyn A; Hyne, Ross V; Stauber, Jenny L; Simpson, Stuart L; Hickey, Christopher W

    2006-06-01

    The sensitivities of eight benthic amphipods, Chaetocorophium cf. lucasi, Corophium colo, Grandidierella japonica, Hyale crassicornis, Hyale longicornis, Melita awa, Melita matilda and Melita plumulosa, to copper and zinc in water-only and whole-sediment toxicity tests were compared. Whole-sediment tests used copper- (1300 mg/kg) and zinc- (4000 mg/kg) spiked sediments after equilibration for sufficient time to produce pore water and overlying water concentrations below the lowest observable effect concentrations of water-only exposures. Survival of adults (after 10 d) and juveniles (after 96 h), and the metal concentrations in the body tissues of adults, were determined at the end of the tests. Two epibenthic amphipods from the genus Melita were the most sensitive species to aqueous copper and zinc, with a 96-h LC50 value of 120 microg Cu/l for both M. awa and M. plumulosa juveniles, and a 96-h LC50 value of 640 microg Zn/l for juveniles of M. plumulosa. Juvenile amphipods (7-d old) were more sensitive than adult amphipods (>30-d old) in both water-only and whole-sediment tests, with adult-LC50/juvenile-LC50 ratios in water-only tests ranging from 1.2 to l.5 for copper and 1 to 1.4 for zinc. All species except C. colo, C. cf. lucasi and M. matilda were sensitive to the copper-spiked sediment, with survival between 14% and 74% of controls. Similarly, all species except C. colo and G. japonica, showed a response to the zinc-spiked sediment (26-81% of control survival). The epibenthic amphipods were more sensitive than the infaunal tube-dwelling amphipods and are recommended as test species.

  4. Effect of water quality and confounding factors on digestive enzyme activities in Gammarus fossarum.

    PubMed

    Charron, L; Geffard, O; Chaumot, A; Coulaud, R; Queau, H; Geffard, A; Dedourge-Geffard, O

    2013-12-01

    The feeding activity and subsequent assimilation of the products resulting from food digestion allow organisms to obtain energy for growth, maintenance and reproduction. Among these biological parameters, we studied digestive enzymes (amylase, cellulase and trypsin) in Gammarus fossarum to assess the impact of contaminants on their access to energy resources. However, to enable objective assessment of a toxic effect of decreased water quality on an organisms' digestive capacity, it is necessary to establish reference values based on its natural variability as a function of changing biotic and abiotic factors. To limit the confounding influence of biotic factors, a caging approach with calibrated male organisms from the same population was used. This study applied an in situ deployment at 23 sites of the Rhone basin rivers, complemented by a laboratory experiment assessing the influence of two abiotic factors (temperature and conductivity). The results showed a small effect of conductivity on cellulase activity and a significant effect of temperature on digestive enzyme activity but only at the lowest temperature (7 °C). The experimental conditions allowed us to define an environmental reference value for digestive enzyme activities to select sites where the quality of the water impacted the digestive capacity of the organisms. In addition to the feeding rate, this study showed the relevance of digestive enzymes as biomarkers to be used as an early warning tool to reflect organisms' health and the chemical quality of aquatic ecosystems.

  5. Microbial proliferation on gill structures of juvenile European lobster ( Homarus gammarus) during a moult cycle

    NASA Astrophysics Data System (ADS)

    Middlemiss, Karen L.; Urbina, Mauricio A.; Wilson, Rod W.

    2015-12-01

    The morphology of gill-cleaning structures is not well described in European lobster ( Homarus gammarus). Furthermore, the magnitude and time scale of microbial proliferation on gill structures is unknown to date. Scanning electron microscopy was used to investigate development of setae in zoea, megalopa and juvenile stages (I-V). Microbes were classified and quantified on gill structures throughout a moult cycle from megalopa (stage IV) to juvenile (stage V). Epipodial serrulate setae, consisting of a naked proximal setal shaft with the distal portion possessing scale-like outgrowths (setules), occur only after zoea stage III. After moulting to megalopa (stage IV), gill structures were completely clean and no microbes were visible on days 1 or 5 postmoult. Microbial proliferation was first evident on day 10 postmoult, with a significant 16-fold increase from day 10 to 15. Rod-shaped bacteria were initially predominant (by day 10); however, by day 15 the microbial community was dominated by cocci-shaped bacteria. This research provides new insights into the morphology of gill-grooming structures, the timing of their development, and the magnitude, timescale and characteristics of gill microbial proliferation during a moult cycle. To some degree, the exponential growth of epibionts on gills found during a moult cycle will likely impair respiratory (gas exchange) and ion regulatory function, yet further research is needed to evaluate the physiological effects of the exponential bacterial proliferation documented here.

  6. Suspension feeding in adult Nephrops norvegicus (L.) and Homarus gammarus (L.) (decapoda)

    NASA Astrophysics Data System (ADS)

    Loo, Lars-Ove; Pihl Baden, Susanne; Ulmestrand, Mats

    Suspension feeding in adults of the Norway lobster Nephrops norvegicus (40-74 g) and the European lobster Homarus gammarus (280-350 g) was tested in experiments offering planktonic food items of different sizes from 200 to 600 μm and measuring the clearing capacity. Both lobster species were found to effectively clear water of food particles comprising nauplii of the brine shrimp Artemia salina of about 600 μm in size. These were reduced to 50% of the initial concentration within 5 h and to 90% within 12 h. When N. norvegicus was offered food particles averaging 200 μm, a significant reduction in average size occurred, indicating that the minimum retention size is around 200 μm. Fluorescently dyed Artemia salina were recovered in the stomach and intestine of lobsters proving that the filtered particles are passed to the digestive tract. Results from other experiments, using the blood pigment (haemocyanin) concentration as an index of nutritional state, indicated that the lobsters can get some nutritional advantage from suspension feeding. Suspension feeding in larger decapods has not been described previously, so the significance of this finding is discussed with respect to changes in behavioural and ecological role.

  7. Changes in amino acids and lipids during embryogenesis of European lobster, Homarus gammarus (Crustacea: Decapoda).

    PubMed

    Rosa, R; Calado, R; Andrade, A M; Narciso, L; Nunes, M L

    2005-02-01

    We studied the amino acid and lipid dynamics during embryogenesis of Homarus gammarus. Major essential amino acids (EAA) in the last stage of embryonic development were arginine, lysine and leucine; major nonessential amino acids (NEAA) were glutamic acid, aspartic acid, valine and glycine. The highest percent of utilization occurred in respect to EAA (27.8%), mainly due to a significant decrease (p<0.05) of methionine (38.3%) and threonine (36.0%). NEAA also decreased significantly (p<0.05, 11.4%), namely serine (38.1%), tyrosine (26.4%) and glutamic acid (25.7%). In contrast, the free amino acid content increased significantly (p<0.05) during embryonic development, especially the free nonessential amino acids (FNEAA). In the last stage, the most abundant FNEAA were glycine, proline, alanine and taurine, and the major free essential amino acids (FEAA) were arginine, lysine and leucine. Lipid content decreased significantly (p<0.05) during embryonic development. A substantial decrease in all neutral lipid classes was observed (>80% of utilization). Major fatty acids were 16:0, 18:0, 18:1n-9, 18:2n-6, 18:3n-3, 20:5n-3 and 22:6n-3. Unsaturated (UFA) and saturated fatty acids (SFA) were used up at similar rates (76.5% and 76.3%, respectively). Within UFA, monounsaturates (MUFA) were consumed more than polyunsaturates (PUFA) (82.9% and 67.5%, respectively). PMID:15649771

  8. Ontogeny of intracellular isosmotic regulation in the european lobster Homarus gammarus (L.).

    PubMed

    Haond, C; Bonnal, L; Sandeaux, R; Charmantier, G; Trilles, J P

    1999-01-01

    Intracellular free amino acids were measured in the abdominal muscle of the three larval instars, postlarvae, and juveniles of the lobster Homarus gammarus, acclimated to seawater (35 per thousand) and to a dilute medium (22 per thousand), to study intracellular isosmotic regulation throughout the development of this species. Transfer to low salinity was followed by a highly significant drop of free amino acids level in all developmental stages. The main regulated amino acids were glycine, proline, and alanine. The level of regulation of total free amino acids changed at metamorphosis: the decrease in total free amino acids at low salinity was 46% in the three larval instars, but it was only 29% in postlarvae and 20% in juveniles. These results suggest that free amino acids, mainly glycine, proline, and alanine, are involved in intracellular isosmotic regulation in the lobster, with different levels of involvement in pre- and postmetamorphic stages. The ontogenetic changes in intracellular isosmotic regulation are discussed in relation to the changes in extracellular regulation (osmoregulation) in the lobster. PMID:10521321

  9. Crustacean hyperglycemic and vitellogenesis-inhibiting hormones in the lobster Homarus gammarus.

    PubMed

    Ollivaux, Céline; Vinh, Joëlle; Soyez, Daniel; Toullec, Jean-Yves

    2006-05-01

    Crustacean hyperglycemic hormone (CHH) and vitellogenesis-inhibiting hormone (VIH), produced by the X organ-sinus gland neurosecretory complex, belong to a peptide group referred to as the CHH family, which is widely distributed in arthropods. In this study, genetic variants and post-translationally modified isoforms of CHH and VIH were characterized in the European lobster Homarus gammarus. With the use of RP-HPLC and ELISA with specific antibodies that discriminate between stereoisomers of CHH and VIH, two groups of CHH-immunoreactive peaks were characterized from HPLC fractions of sinus gland extract (CHH A and CHH B); each group contained two variants (CHH and D-Phe3CHH). In the same way, two VIH-immunoreactive peaks (VIH and D-Trp4VIH) were demonstrated in HPLC fractions from sinus gland extract. The masses of these different neuropeptides were determined by FT-ICR MS: CHH A and CHH B spectra exhibited monoisotopic ions at 8557.05 Da and 8527.04 Da, respectively, and both VIH isomers displayed an m/z value of 9129.19 Da. Two full-length cDNAs encoding preprohomones of CHH A and CHH B and only one cDNA for VIH precursor were cloned and sequenced from X organ RNA. Comparison of CHH sequences between European lobster and other Astacoidea suggests that the most hydrophobic form appeared first during crustacean evolution. PMID:16649992

  10. How Biotransformation Influences Toxicokinetics of Azole Fungicides in the Aquatic Invertebrate Gammarus pulex.

    PubMed

    Rösch, Andrea; Anliker, Sabine; Hollender, Juliane

    2016-07-01

    Biotransformation is a key process that can greatly influence the bioaccumulation potential and toxicity of organic compounds. In this study, biotransformation of seven frequently used azole fungicides (triazoles: cyproconazole, epoxiconazole, fluconazole, propiconazole, tebuconazole and imidazoles: ketoconazole, prochloraz) was investigated in the aquatic invertebrate Gammarus pulex in a 24 h exposure experiment. Additionally, temporal trends of the whole body internal concentrations of epoxiconazole, prochloraz, and their respective biotransformation products (BTPs) were studied to gain insight into toxicokinetic processes such as uptake, elimination and biotransformation. By the use of high resolution tandem mass spectrometry in total 37 BTPs were identified. Between one (ketoconazole) and six (epoxiconazole) BTPs were identified per parent compound except for prochloraz, which showed extensive biotransformation reactions with 18 BTPs detected that were mainly formed through ring cleavage or ring loss. In general, most BTPs were formed by oxidation and conjugation reactions. Ring loss or ring cleavage was only observed for the imidazoles as expected from the general mechanism of oxidative ring openings of imidazoles, likely affecting the bioactivity of these BTPs. Overall, internal concentrations of BTPs were up to 3 orders of magnitude lower than that of the corresponding parent compound. Thus, biotransformation did not dominate toxicokinetics and only played a minor role in elimination of the respective parent compound, with the exception of prochloraz. PMID:27232586

  11. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Pacific Northwest): Amphipods. [Gammaridea; Hyperidea; Caprellidea

    SciTech Connect

    Grosse, D.J.; Pauley, G.B.; Moran, D.

    1986-08-01

    Amphipods are ubiquitous in distribution. Hyperiidea are the third most abundant coastal marine crustacean zooplankton, following copepods and euphausids. Benthic Gammaridea are an invaluable food source for many economically important fish and invertebrate species. Lifestyles of the major amphipod groups are varied. On the basis of the Index of Relative Importance (IRI), they comprise more than half of the total IRI spectrum for 38 of 55 fish species in the Strait of Juan de Fuca. They are reported to be indicators of heavily polluted areas.

  12. Antioxidant response to natural organic matter (NOM) exposure in three Baikalean amphipod species from contrasting habitats.

    PubMed

    Timofeyev, M A; Steinberg, C E W

    2006-10-01

    The aim of the present work is to comparatively evaluate the oxidative stress response on exposure to natural organic matter (NOM) in three amphipod (Crustacea, Amphipoda) species from different taxonomic groups and different habitats of Lake Baikal. Endemic species from Lake Baikal were used: the shallow-water dwelling Gmelinoides fasciatus (Dyb.), Pallasea cancelloides (Gerstf.), and the deep-layer inhabitant Ommatogammarus flavus (Dyb.). Three key enzymes, catalase (CAT), peroxidase (POD), and glutathione S-transferase (GST), were studied. The applied NOM from Lake Schwarzer (Germany) directly impacts the two littoral species which quickly respond. The response is characterized by a significant decrease of POD and an increase of CAT activities. GST activity remains stable or decreased slightly. In contrast to the littoral amphipods, the deep-layer inhabitant O. flavus showed no significant reaction to NOM exposure, probably due to decreased adaptive ability of this species. The stable environment of the Baikalean deep zones obviously does not provide triggers for the development of flexible antioxidant or general defense systems. PMID:16914340

  13. Acute and chronic toxicity of lead in water and diet to the amphipod Hyalella azteca

    USGS Publications Warehouse

    Besser, J.M.; Brumbaugh, W.G.; Brunson, E.L.; Ingersoll, C.G.

    2005-01-01

    We evaluated the influence of waterborne and dietary lead (Pb) exposure on the acute and chronic toxicity of Pb to the amphipod Hyalella azteca. Test solutions were generated by a modified diluter with an extended (24-h) equilibration period. Acute (96-h) toxicity of Pb varied with water hardness in the range of 71 to 275 mg/L as CaCO3, despite similar dissolved Pb concentrations. Acute toxicity was greatest in soft test water, with less than 50% survival at the lowest dissolved Pb concentration (151 ??g/L). Survival also was significantly reduced in medium-hardness water but not in hard test water. In chronic (42-d) studies, amphipods were exposed to waterborne Pb and fed either a control diet or a diet equilibrated with waterborne Pb levels. For animals fed the control diet, the median lethal concentration (LC50) for Pb was 24 ??g/L (as dissolved Pb), and significant reductions in survival occurred at 16 ??g/L. Exposure to Pb-treated diets significantly increased toxicity across a wide range of dissolved Pb concentrations, with a LC50 of 16 ??g/L and significant reductions in growth and reproduction at 3.5 ??g/L. Significant effects on growth and reproduction occurred at dissolved Pb concentrations close to the current U.S. chronic water-quality criterion. Our results suggest that both aqueous- and dietary-exposure pathways contribute significantly to chronic Pb exposure and toxic effects in aquatic biota. ?? 2005 SETAC.

  14. Seasonal variability of metabolic markers and oxidative balance in freshwater amphipod Hyalella kaingang (Crustacea, Amphipoda).

    PubMed

    Braghirolli, Fernando Machado; Oliveira, Maiara Rodriguez; Oliveira, Guendalina Turcato

    2016-08-01

    Amphipods are widely used as bioindicator organisms, in view of their ease of collection and cultivation, sexual dimorphism and abundance, in aquatic environments. In the present study male (n=30) and female (n=30) amphipod Hyalella kaingang were collected during the middle of each season from a nature preserve (Research Center PRÓ-MATA) in São Francisco de Paula, Southern Brazil. Proteins, glycogen, lipids, triglycerides, glycerol, and lipid peroxidation (superoxide dismutase, catalase, and glutathione S-transferase activity) were measured. The results obtained for the markers of energy metabolism, antioxidant enzymes, and lipid peroxidation revealed a clear seasonal variation. The patterns of proteins, glycerol, and glutathione S-transferase activity did not differ between sexes; conversely, differential responses in males and females over the year were observed for all other parameters (glycogen, lipids, triglycerides, lipid peroxidation, and superoxide dismutase and catalase activity). These responses appear to be strongly influenced by a prolonged reproductive period (autumn through spring, peaking in autumn); by the degree of exploratory activity, particularly in the summer and autumn; and by abiotic factors, such as temperature and photoperiod. The responses observed in the summer and autumn (decrease in levels of proteins, glycogen and fats, and increase in lipid peroxidation levels and glutathione S-transferase activity), suggest that this season represents a critical time point for these animals. The parameters studied herein may be used as biomarkers to assess the environmental conditions in the aquatic habitat. PMID:27107775

  15. Effects of sediment amended with Deepwater Horizon incident slick oil on the infaunal amphipod Leptocheirus plumulosus.

    PubMed

    Lotufo, Guilherme R; Farrar, J Daniel; Biedenbach, James M; Laird, Jennifer G; Krasnec, Michelle O; Lay, Claire; Morris, Jeffrey M; Gielazyn, Michel L

    2016-08-15

    Crude oil released from the Deepwater Horizon disaster into the Gulf of Mexico posed potential impacts to infaunal invertebrates inhabiting near shore habitats. The effects of sediment-associated weathered slick oil on the amphipod Leptocheirus plumulosus was assessed using 28-d exposures to total PAH sediment concentrations ranging from 0.3 to 24mg/kg (sum of 50 PAHs or tPAH50). Survival and growth rate were significantly decreased in the 2.6, 11.4 and 24.2mg/kg treatments, but only growth in 5.5mg/kg. Offspring production was dramatically decreased but was variable and significantly different only for 24.2mg/kg. The concentrations associated with 20% decreases relative to reference were 1.05 (95% CI=0-2.89) mg/kg tPAH50 for growth rate and 0.632 (95% CI=0.11-2.15) mg/kg tPAH50 for offspring production. The concentrations of PAHs affecting amphipods are within the range of concentrations measured in marsh areas reportedly impacted by DWH oil after its release. PMID:27267114

  16. The tropical caprellid amphipod Paracaprella pusilla: a new alien crustacean in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Ros, Macarena; Vázquez-Luis, Maite; Guerra-García, José Manuel

    2013-12-01

    Paracaprella pusilla Mayer (Fauna und Flora des Golfes von Neapel 17:1-55, 1890), originally described from Brazil, is one of the most abundant caprellid amphipod species in tropical and subtropical seas around the world. During a survey of caprellid amphipods from marinas along the Balearic Island (Western Mediterranean Sea) carried out between November 2011 and August 2012, we found two established populations of P. pusilla in Mallorca and Ibiza, respectively. So far, its occurrence in European waters was reported only from southwestern Spain in 2010. This record represents a northward range expansion of the species' distribution, which is found for the first time in the Mediterranean. This is also the first record of the genus Paracaprella in the Mediterranean Sea. The most probable introduction vector was ship fouling. We also found the invasive caprellid Caprella scaura Templeton (Trans Entomol Soc Lond 1:185-198, 1836) in Mallorca and Menorca, which is recorded for the first time in the Balearic Islands, confirming its rapid expansion along the Mediterranean. When comparing reproductive traits between both alien species, we found that P. pusilla has a higher fecundity than C. scaura for the same female size. Taking into account this evidence, the species may be expected to appear in other Mediterranean and adjacent areas.

  17. Sediment toxicity testing with the amphipod Ampelisca abdita in Calcasieu Estuary, Louisiana

    USGS Publications Warehouse

    Redmond, M.S.; Crocker, P.A.; McKenna, K.M.; Petrocelli, E.A.; Scott, K.J.; Demas, C.R.

    1996-01-01

    Discharges from chemical and petrochemical manufacturing facilities have contaminated portions of Louisiana's Calcasieu River estuary with a variety of organic and inorganic contaminants. As part of a special study, sediment toxicity testing was conducted to assess potential impact to the benthic community. Ten-day flow-through sediment toxicity tests with the amphipod Ampelisca abdita revealed significant toxicity at 68% (26 of 38) of the stations tested. A. abdita mortality was highest in the effluent-dominated bayous, which are tributaries to the Calcasieu River. Mortality was correlated with total heavy metal and total organic compound concentrations in the sediments. Ancillary experiments showed that sediment interstitial water salinity as low as 2.5 o/o-o did not significantly affect A. abdita's, response in the flow-through system; sediment storage for 7 weeks at 4??C did not significantly affect toxicity. Sediment toxicity to A. abdita was more prevalent than receiving water toxicity using three short-term chronic bioassays. Results suggest that toxicity testing using this amphipod is a valuable tool when assessing sediments containing complex contaminant mixtures and for assessing effects of pollutant loading over time. In conjunction with chemical analyses, the testing indicated that the effluent-dominated, brackish bayous (Bayou d'Inde and Bayou Verdine) were the portions of the estuary most impacted by toxicity.

  18. Life history and population dynamics of an estuarine amphipod, Eriopisa chilkensis Chilton (Gammaridae)

    NASA Astrophysics Data System (ADS)

    Aravind, Nisha P.; Sheeba, P.; Nair, K. K. C.; Achuthankutty, C. T.

    2007-08-01

    The life cycle of the gammarid amphipod Eriopisa chilkensis Chilton from the Cochin estuary, south west coast of India, has been studied for the first time under laboratory conditions. Amphipods, especially gammarids, are used as potential live feed in fish culture. Eriopisa chilkensis can withstand wide variations in salinity (5-35) and temperature (27.5-34 °C) of the medium. It was cultured in un-aerated finger bowls using dried algal matter ( Chara sp.) as food. The life span of females was found to be higher (maximum: 220 days) than males (maximum: 175 days). Females were iteroparous and attained sexual maturity within 39.3 ± 6 days (mean ± SD), whereas males matured within 26.5 ± 5.6 days. Number of broods in a life span ranged from 4 to 7. The maximum number of juveniles produced in a single brood was 29 and the maximum number of juveniles produced by a single female over a lifetime was 139. The duration of embryonic development was 12 ± 2.45 days. The population dynamics of E. chilkensis was studied based on monthly sampling, over one year from the mangrove swamps of Puduvypin. It occurred in varying densities in the epifaunal community (21-1583 ind. m -2). Extrapolation of laboratory data to the field suggests that E. chilkensis in Cochin estuary has a multivoltine life cycle.

  19. Critical body residues in the marine amphipod Ampelisca abdita: Sediment exposures with nonionic organic contaminants

    SciTech Connect

    Fay, A.A.; Brownawell, B.J.; Elskus, A.A.; McElroy, A.E.

    2000-04-01

    Body residues associated with acute toxicity were determined in the marine amphipod Ampelisca abdita exposed to spiked sediments. Nonylphenol and 2,2{prime},4,4{prime}-tetrachlorobiphenyl critical body residues (CBRs, body residue of contaminant at 50% mortality) were 1.1 {micro}mol/g wet tissue and 0.57 {micro}mol/g wet tissue, respectively, values near the low end of the CBR range expected for compounds acting via narcosis. The polycyclic aromatic hydrocarbons tested, benzo[a]pyrene (BaP) and benz[a]anthracene (BaA), were not acutely toxic at exposure concentrations of up to 43 and 1,280 {micro}g/g dry sediment for BaA and BaP respectively, and body burdens up to 1.2 {micro}mol/g wet tissue (for BaP). Neither polycyclic aromatic hydrocarbon (PAH) was significantly metabolized by A. abdita. The microextraction technique employed here allowed residue analysis of samples containing as few as three amphipods (0.33 mg dry wt). The CBR approach avoids confounding factors such as variations in bioavailability and uptake kinetics and could be employed to assess the relative contribution of specific contaminants or contaminant classes in mixtures to effects observed in toxicity tests with Ampelisca and other organisms.

  20. Do amphipods have the same concentration-response to contaminated sediment in situ as in vitro?

    SciTech Connect

    DeWitt, T.H.; Hickey, C.W.; Morrisey, D.J.; Williamson, R.B.; Dam, L. van; Williams, E.K.; Nipper, M.G.; Roper, D.S.

    1999-05-01

    An underlying assumption of laboratory-based toxicity tests is that the sensitivity of organisms in the laboratory (in vitro) is comparable to that in the field (in situ). The authors tested this assumption by exposing estuarine amphipods (Chaetocorophium cf. lucasi) to a concentration series of cadmium-spiked sediments in vitro and in situ for 10 d. In situ exposures were conducted within plastic-mesh cages on an intertidal mudflat. To characterize exposure, they measured interstitial water cadmium concentrations (IW{sub Cd}), acid volatile sulfide (AVS), and simultaneously extracted Cd (SEM{sub Cd}) at the beginning and end of the exposures. Between day 0 and day 10, AVS decreased in both in vitro and in situ exposures, while IW{sub Cd} levels declined less in vitro than in situ (median 76%). Despite more extreme conditions of temperature and salinity in situ, in vitro and in situ exposures showed comparable survival responses based on SEM{sub Cd}/AVS with the onset of marked mortality above a SEM{sub Cd}/AVS value of about one and minimal survival (< 5%) above a value of two. Based on IW{sub Cd} concentrations, however, sensitivity was significantly greater in vitro. They concluded that, in their tests, amphipod sensitivity in vitro was equal to or greater than its sensitivity in situ.

  1. Genetic structure of the benthic amphipod Diporeia (Amphipoda: Pontoporeiidae) and its relationship to abundance in Lake Superior

    EPA Science Inventory

    The freshwater amphipod Diporeia is a crucial part of the food web in the Laurentian Great Lakes, but has faced serious declines correlated with the invasion of zebra mussels (Dreissena polymorpha), except in Lake Superior, which has seen an increase in Diporeia abundance. Specul...

  2. Phototoxicity of TiO2 nanoparticles to a freshwater benthic amphipod: are benthic systems at risk?

    EPA Science Inventory

    This study investigated phototoxicity of TiO2 nanoparticles (nano-TiO2) to a freshwater benthic amphipod (Hyalella azteca) using 48-h and 96-h bioassays. Thorough monitoring of particle interactions with exposure media (Lake Superior water, LSW) and the surface of organisms was p...

  3. Evaluation of the Influence of Bromide or Iodide on the Performance the Amphipod Hyalella azteca in Reconstituted Waters

    EPA Science Inventory

    Survival, growth, or reproduction of the amphipod Hyalella azteca (HA) is reported to be poor when some reconstituted waters have been used to conduct chronic (>14-d) water-only or sediment toxicity tests, including ASTM reconstituted hard water (with no addition of Bromi...

  4. Proteomics in aquatic amphipods: can it be used to determine mechanisms of toxicity and interspecies responses after exposure to atrazine?

    PubMed

    Ralston-Hooper, Kimberly J; Sanchez, Brian C; Adamec, Jiri; Sepúlveda, María S

    2011-05-01

    Proteomics has gained popularity in the field of ecotoxicology as a holistic tool for unraveling novel mechanisms of toxicity and elucidating subtle effects of contaminant exposure. The holoarctic amphipod Diporeia spp. is declining at precipitous rates in the Great Lakes, and we are evaluating the use of the well-studied amphipod model Hyalella azteca as a surrogate for Diporeia spp. This article presents proteomics data from both amphipod species exposed to atrazine (ATZ) and one of its metabolites, desethylatrazine (DEA; 3 and 30 µg/L for 21 and 42 d). We used a proteomics approach to determine whether these two species of amphipods responded similarly to the same chemicals and to understand better the mechanisms of toxicity of ATZ and DEA in aquatic invertebrates. We observed disruption in energy production and mitochondrial function as well as hormesis in exposed organisms. In addition, we identified a two proteins (GAPDH and HSP 90 kDa) that have been linked to hormonal disruptions, suggesting potential endocrine disruption. Finally, we found that H. azteca and Diporeia spp. responded with similar proteomic profiles after ATZ and DEA exposure, suggesting that H. azteca may be used as a surrogate model organism for Diporeia spp.

  5. Influence of bioturbation by the amphipod Corophium volutator on fluoranthene uptake in the marine polychaete Nereis virens

    SciTech Connect

    Ciarelli, S.; Kater, B.J.; Straalen, N.M. van

    2000-06-01

    The uptake kinetics of fluoranthene in the polychaete worm Nereis virens were investigated in the presence and in the absence of amphipods to examine the effects of sediment bioturbation by the benthic amphipod Corophium volutator on the uptake in worms. Worms only and worms together with two different densities of amphipods were exposed to fluoranthene-spiked sediment for 12 d. Worms and overlying water samples for fluoranthene analyses were taken and total suspended solids in water column were measured after 1, 2, 5, 8, and 12 d. Results showed that in all treatments fluoranthene was rapidly accumulated by N. virens during the first two days and a steady state was reached within five days of exposure. Biota to sediment accumulation factors normalized to lipid concentration and to sediment organic carbon (BAF{sub ioc}) or worms exposed with the highest number of amphipods were significantly higher (two to three times) compared to worms exposed with fewer or without amphipods after one and two days of exposure. Bioconcentration factors (BCFs), calculated as the ratio between the uptake (k{sub 1}) and elimination (k{sub 2}) rate constants were not significantly different among treatments. When BCFs were calculated on the basis of dissolved fluoranthene concentrations (BCF{sub diss}), values of the treatments where worms were exposed with 100 and 300 amphipods were slightly higher than those calculated on the basis of total (dissolved + particle-bound) aqueous fluoranthene (BCF{sub tot}). However, the presence of fluoranthene bound to dissolved organic matter could have accounted for lower than expected BCF{sub diss} values. The results suggest that bioturbation by amphiopoc, affected the concentration of fluoranthene in the worms not by changing the worm to water partitioning (k{sub 1}/k{sub 2}) but by changing the worm to sediment partitioning (BAF{sub ioc}). In the treatments with worms a higher mortality of amphipods was found compared to those without worms. The

  6. Sediment toxicity, contamination and amphipod abundance at a DDT- and dieldrin-contaminated site in San Francisco Bay

    SciTech Connect

    Swartz, R.C.; Cole, F.A.; Lamberson, J.O.; Ferraro, S.P.; Schults, D.W.

    1994-01-01

    Sediment toxicity to the amphipod Eohaustorius estuarius, sediment contamination, and the abundance of amphipods were examined along a contamination gradient in the Lauritzen Channel and adjacent parts of Richmond Harbor, California. Dieldrin and DDT were formulated and ground at this site from 1945 to 1966. Sediment contamination by both dieldrin and the sum of DDT and its metabolites (DDT's) was positively correlated with sediment toxicity and negatively correlated with the abundance of amphipods excluding Grandidierella japonica. The maximum dieldrin and DDT's concentrations in toxic units were 0.018 and 9.43, respectively, indicating that DDT's was the dominant ecotoxicological factor. Concentrations of PAHs, PCBs, and metals were not sufficient to cause appreciable toxicity, except at one PAH-contaminated station. Relations between DDT's, sediment toxicity, and amphipod abundance are similar at three DDT's-contaminated sites. The 10-d LC50 for DDT's in field-collected sediment was 2,500 micrograms/gram organic carbon (OC) for Eohaustorius estuarius in the study, 1,040 micrograms/gram OC for Rhepoxynius abronius exposed to Palos Verdes Shelf, California, sediment, and 2,580 micrograms/gram OC for Hyalella azteca exposed to sediment from a freshwater stream system near Huntsville, Alabama. The threshold for 10-d sediment toxicity occurred at about 300 micrograms DDT's/gram OC. The abundance of amphipods (except Grandidierella japonica) was reduced at DDT's concentrations >100 micrograms/gram OC. Correlations between toxicity, contamination, and biology indicate that acute sediment toxicity to Eohaustorius estuarius, Rhopoxynius abronius, or Hyalella azteca in lab tests provides reliable evidence of biologically adverse sediment contamination in the field.

  7. Distribution of amphipods Ischyrocerus on the red king crab, Paralithodes camtschaticus: Possible interactions with the host in the Barents Sea

    NASA Astrophysics Data System (ADS)

    Dvoretsky, Alexander G.; Dvoretsky, Vladimir G.

    2009-04-01

    The determination of costs and benefits experienced by crustaceans as a result of occupation by their symbionts has received increased attention from marine ecologists. However, the interactions between some important species and their associates remain unclear. We examined the distribution of amphipods in the genus Ischyrocerus on the red king crab Paralithodes camtschaticus, a commercially important species, in two areas of the Barents Sea. Ischyrocerus commensalis was found on 30.5% of crabs in Dalnezelenetskaya Bay (DZB) with the mean number per crab being 55.1, in Dolgaya Bay (DLB) these rates were 28.6% with 19.3 specimens per crab. Sympatric species Ischyrocerus anguipes was found on 13.5% of crabs in DZB with a mean of 7.3 individuals per host, in DLB it had much lower occurrence (1.3% and 1.5 specimens per host). There were no significant differences between proportions of male and female crabs infested by amphipods in both areas examined. Prevalence of amphipods was similar among years examined except for I. commensalis on small crabs (carapace length CL <90 mm) and I. anguipes on large crabs (CL >90 mm) in DZB. We found that I. commensalis and I. anguipes are not egg predators of P. camtschaticus in the Barents Sea, at least in summer. High numbers of I. commensalis occur in crab gills, and both mean intensity of the amphipods and their empty tubes increased with crab size. In the gills, I. commensalis predominated in the section nearest the mouth parts. Possible negative impacts for the hosts due to gills infestation are discussed. In contrast, I. anguipes were predominately found on the carapace and limbs of crabs and appears to be a less specific symbiont of P. camtschaticus. Both amphipod species seem to be commensals, however possible negative impacts for the host could not be excluded.

  8. Sensitivity of the deep-sea amphipod Eurythenes gryllus to chemically dispersed oil.

    PubMed

    Olsen, Gro Harlaug; Coquillé, Nathalie; Le Floch, Stephane; Geraudie, Perrine; Dussauze, Matthieu; Lemaire, Philippe; Camus, Lionel

    2016-04-01

    In the context of an oil spill accident and the following oil spill response, much attention is given to the use of dispersants. Dispersants are used to disperse an oil slick from the sea surface into the water column generating a cloud of dispersed oil droplets. The main consequence is an increasing of the sea water-oil interface which induces an increase of the oil biodegradation. Hence, the use of dispersants can be effective in preventing oiling of sensitive coastal environments. Also, in case of an oil blowout from the seabed, subsea injection of dispersants may offer some benefits compared to containment and recovery of the oil or in situ burning operation at the sea surface. However, biological effects of dispersed oil are poorly understood for deep-sea species. Most effects studies on dispersed oil and also other oil-related compounds have been focusing on more shallow water species. This is the first approach to assess the sensitivity of a macro-benthic deep-sea organism to dispersed oil. This paper describes a toxicity test which was performed on the macro-benthic deep-sea amphipod (Eurythenes gryllus) to determine the concentration causing lethality to 50% of test individuals (LC50) after an exposure to dispersed Brut Arabian Light (BAL) oil. The LC50 (24 h) was 101 and 24 mg L(-1) after 72 h and 12 mg L(-1) at 96 h. Based on EPA scale of toxicity categories to aquatic organisms, an LC50 (96 h) of 12 mg L(-1) indicates that the dispersed oil was slightly to moderately toxic to E. gryllus. As an attempt to compare our results to others, a literature study was performed. Due to limited amount of data available for dispersed oil and amphipods, information on other crustacean species and other oil-related compounds was also collected. Only one study on dispersed oil and amphipods was found, the LC50 value in this study was similar to the LC50 value of E. gryllus in our study. Since toxicity data are important input to risk assessment and net environmental

  9. Sensitivity of the deep-sea amphipod Eurythenes gryllus to chemically dispersed oil.

    PubMed

    Olsen, Gro Harlaug; Coquillé, Nathalie; Le Floch, Stephane; Geraudie, Perrine; Dussauze, Matthieu; Lemaire, Philippe; Camus, Lionel

    2016-04-01

    In the context of an oil spill accident and the following oil spill response, much attention is given to the use of dispersants. Dispersants are used to disperse an oil slick from the sea surface into the water column generating a cloud of dispersed oil droplets. The main consequence is an increasing of the sea water-oil interface which induces an increase of the oil biodegradation. Hence, the use of dispersants can be effective in preventing oiling of sensitive coastal environments. Also, in case of an oil blowout from the seabed, subsea injection of dispersants may offer some benefits compared to containment and recovery of the oil or in situ burning operation at the sea surface. However, biological effects of dispersed oil are poorly understood for deep-sea species. Most effects studies on dispersed oil and also other oil-related compounds have been focusing on more shallow water species. This is the first approach to assess the sensitivity of a macro-benthic deep-sea organism to dispersed oil. This paper describes a toxicity test which was performed on the macro-benthic deep-sea amphipod (Eurythenes gryllus) to determine the concentration causing lethality to 50% of test individuals (LC50) after an exposure to dispersed Brut Arabian Light (BAL) oil. The LC50 (24 h) was 101 and 24 mg L(-1) after 72 h and 12 mg L(-1) at 96 h. Based on EPA scale of toxicity categories to aquatic organisms, an LC50 (96 h) of 12 mg L(-1) indicates that the dispersed oil was slightly to moderately toxic to E. gryllus. As an attempt to compare our results to others, a literature study was performed. Due to limited amount of data available for dispersed oil and amphipods, information on other crustacean species and other oil-related compounds was also collected. Only one study on dispersed oil and amphipods was found, the LC50 value in this study was similar to the LC50 value of E. gryllus in our study. Since toxicity data are important input to risk assessment and net environmental

  10. Effect of an insect juvenile hormone analogue, Fenoxycarb on development and oxygen uptake by larval lobsters Homarus gammarus (L.).

    PubMed

    Arnold, Katie E; Wells, Colin; Spicer, John I

    2009-04-01

    Little attention has been focused on the effect of anthropogenic compounds that disrupt the endocrine systems in crustaceans. Consequently, this study investigated the effects of the juvenile hormone analogue (JHA), Fenoxycarb on selected physiological and developmental processes of the zoeal stages in the European lobster, Homarus gammarus. Chronic exposure to Fenoxycarb (50microg L(-1)) resulted in a significant (p < 0.05) reduction in moult frequency and size at moult. Fenoxycarb exposure extended zoeal duration between zoea I to II (p<0.05) and resulted in total inhibition of the moult from zoea II to III. Significantly greater rates of O2 uptake were observed in Fenoxycarb-exposed larvae in comparison with controls (p<0.05). All rates of O2 uptake decreased significantly between 7 and 12d of exposure (p<0.05). At 12d, exposure to the solvent control no longer influenced rates of O2 uptake, but it was not possible to attribute increased O2 uptake to Fenoxycarb exposure directly, as treated individuals did not moult beyond zoea III. The low exposure concentrations of Fenoxycarb, comparable to those used in plant protection, resulted in endocrine disrupted responses in H. gammarus (albeit with little clear, demonstrable effect on metabolism) a finding that could have important ecological and commercial implications. PMID:18835588

  11. Confocal laser scanning and electron microscopical studies on osmoregulatory epithelia in the branchial cavity of the lobster homarus gammarus

    PubMed

    Haond; Flik; Charmantier

    1998-06-01

    The adult lobster Homarus gammarus is a weak hyper-regulator at low salinity. The objective of this study was to locate the ion-transporting tissues in the branchial chamber of this species, using electron microscopy and confocal laser scanning microscopy with a fluorescent vital stain for mitochondria, DASPMI, which is widely used to locate mitochondria-rich cells in ion-transporting epithelia of fish. A thick mitochondria-rich epithelium is present on the inner side of the branchiostegite and over the entire surface of the epipodites. Ultrastructural observations confirm that this tissue has features typical of an ion-transporting epithelium. When the lobster is transferred to low salinity, these epithelia undergo marked ultrastructural changes, such as an increase in thickness related to the development of basolateral infoldings, the appearance of numerous vesicles and an increase in height of the apical microvilli. In the gills, the branchial filaments are lined by a thin and poorly differentiated epithelium, containing numerous mitochondria; no significant ultrastructural changes were observed in the gills of animals acclimated to low salinity. In summary, in H. gammarus, no evidence of osmoregulatory structures was found in the gills. Differentiated ion-transporting epithelia are present in the branchial cavity, on the inner side of the branchiostegite and on the epipodites; these organs are probably involved in osmoregulation. PMID:9576892

  12. Effects of temperature and salinity on the development of the amphipod crustacean Eogammarus sinensis

    NASA Astrophysics Data System (ADS)

    Xue, Suyan; Fang, Jianguang; Zhang, Jihong; Jiang, Zengjie; Mao, Yuze; Zhao, Fazhen

    2013-09-01

    The amphipod crustacean Eogammarus sinensis has useful features that make it suitable for use in the aquaculture of fish and large decapod crustaceans. In this study, we investigated the effects of temperature and salinity on the development, fecundity, survival, and growth rate of E. sinensis. The results show that temperature significantly affected E. sinensis development, but salinity. As temperature increased, the duration of E. sinensis embryonic development decreased. Fecundity was affected significantly by temperature and the combination of temperature and salinity, but by salinity alone. In addition, high temperatures accelerated E. sinensis juvenile growth rates, whereas high salinity reduced it. Therefore, our data suggest that E. sinensis tolerates a wide range of salinities and that temperature has more significant effects than salinity on the embryonic development, fecundity, and growth of E. sinensis. Our results shall be useful for mass production of this species for use in aquaculture.

  13. A simple control for sediment-toxicity exposures using the amphipod, Hyalella azteca

    USGS Publications Warehouse

    Lasier, Pete; Urich, Matthew L.

    2014-01-01

    Sediment-toxicity exposures comparing survival and growth of the freshwater amphipod, Hyalella azteca, are often components of aquatic-habitat assessments. Standardized exposure methods have been established and require evaluations for quality assurance. Test acceptability using performance-based criteria can be determined from exposures to control sediments, which are collected from the environment or formulated from commercially available components. Amending sand with leached alfalfa solids provided a simple formulated sediment that elicited consistently acceptable survival and growth in 28-day exposures with and without a daily feeding regime. A procedure is described for preparing the sediment along with results from comparisons among sand, amended sand, and field-collected sediments that incorporated three feeding regimes.

  14. Transcriptome of the Antarctic amphipod Gondogeneia antarctica and its response to pollutant exposure.

    PubMed

    Kang, Seunghyun; Kim, Sanghee; Park, Hyun

    2015-12-01

    Gondogeneia antarctica is widely distributed off the western Antarctic Peninsula and is a key species in the Antarctic food web. In this study, we performed Illumina sequencing to produce a total of 4,599,079,601 (4.6Gb) nucleotides and a comprehensive transcript dataset for G. antarctica. Over 46 million total reads were assembled into 20,749 contigs, and 12,461 annotated genes were predicted by Blastx. The RNA-seq results after exposure to three pollutants showed that 658, 169 and 367 genes that were potential biomarkers of responses to pollutants for this species were specifically upregulated after exposure to PCBs (Polychlorinated biphenyls), PFOS (Perfluorooctanesulfonic acid) and PFOA (Perfluorooctanoic acid), respectively. These data represent the first transcriptome resource for the Antarctic amphipod G. antarctica and provide a useful resource for studying Antarctic marine species.

  15. Distribution and behavior of scavenging amphipods from the central North Pacific

    NASA Astrophysics Data System (ADS)

    Ingram, Camilla L.; Hessler, Robert R.

    1983-07-01

    Deep-sea scavenging amphipod distributions, abundance, and behavior were studied with five-vehicle baited traps. The species composition and numerical abundances were comparable in the areas sampled. All size classes of the four predominant species ( Paralicella caperesca, P. tenuipes, Orchomene gerulicorbis, and Eurythenes gryllus) were trapped including sexually mature individuals, but no females were ovigerous. The central North Pacific E. gryllus is morphologically distinct from Atlantic E. gryllus and may represent a different species. Pelagic and demersal amphipod guilds exist, as determined by body size and vertical and horizontal distributional patterns. The demersal guild is composed of P. caperesca, P. tenuipes, and O. gerulicorbis, all of which are <2 cm in total body length and occur within 1 m of the sediment. E. gryllus, the only representative of the pelagic guild, ranges between 1.7 and 14 cm in total body length and has its greatest abundance several to tens of meters above the sediment. Members of the demersal guild probably can detect and exploit both large and small food falls or autochthonous organic particles because of their proximity to the sediment. They reside within the area of the benthic boundary layer where currents are slowest, and the diffusion of odor is slower than higher in the water column, thus reducing the area from which they can be attracted to a food item. The vertical distribution of E. gryllus correlates well with several physical features of the benthic boundary layer. Their vertical abundance increases an order of magnitude near the top of the Ekman layer, correlating with the increase in current velocities. It continues to increase up to 20 m, corresponding with the probable vertical extent of more than two-thirds of an odor trace. Their abundance decreases significantly above 20 m. The above correlations imply that the vertical distribution of E. gryllus is an adaptation that provides a wide chemosensory overview of

  16. A simple control for sediment-toxicity exposures using the amphipod, Hyalella azteca.

    PubMed

    Lasier, Peter J; Urich, Matthew L

    2014-09-01

    Sediment-toxicity exposures comparing survival and growth of the freshwater amphipod, Hyalella azteca, are often components of aquatic-habitat assessments. Standardized exposure methods have been established and require evaluations for quality assurance. Test acceptability using performance-based criteria can be determined from exposures to control sediments, which are collected from the environment or formulated from commercially available components. Amending sand with leached alfalfa solids provided a simple formulated sediment that elicited consistently acceptable survival and growth in 28-day exposures with and without a daily feeding regime. A procedure is described for preparing the sediment along with results from comparisons among sand, amended sand, and field-collected sediments that incorporated three feeding regimes. PMID:25015186

  17. Development of a chronic sublethal sediment bioassay using the estuarine amphipod Leptocheirus plumulosus (Shoemaker)

    SciTech Connect

    Emery, V.L. Jr.; Moore, D.W.; Gibson, A.B.; Gray, B.R.; Duke, B.M.; Wright, R.B.; Farrar, J.D.

    1997-09-01

    Based on the need for a test to evaluate chronic sublethal toxicity in estuarine sediments, a 28-d sediment bioassay with the estuarine amphipod, Leptocheirus plumulosus (Shoemaker) was developed. The test was initiated with animals less than 2 weeks old. Test endpoints included survival, growth, and reproduction. Factors with the potential to influence test animal performance such as artificial sea salts, salinity, food ration, size at test initiation, intraspecific density, sediment grain size, and diet were evaluated. For example, intraspecific densities between 10 and 60 animals/beaker did not affect survival, growth, or reproduction. Similarly, L. plumulosus were tolerant of a wide range of sediment grain sizes with only extremely fine grained or coarse grained material significantly affecting survival, growth, and reproduction. Test performance criteria included control survival (> 80%) and reproduction and response to a reference toxicant test with cadmium chloride in a control chart format.

  18. Bioavailability and chronic toxicity of cadmium in sediment to the estuarine amphipod Leptocheirus plumulosus

    SciTech Connect

    DeWitt, T.H.; Swartz, R.C.; Hansen, D.J.; McGovern, D.; Berry, W.J.

    1996-12-01

    Numerous studies have demonstrated the efficacy of interstitial water metal concentrations and simultaneously extracted metals/acid-volatile sulfide (SEM/AVS) ratios in explaining the acute toxicity of sediment-associated metals to benthic organisms. However, no full life-cycle chronic marine or estuarine tests have been conducted for this purpose. In this study, cohorts of newborn amphipods, Leptocheirus plumulosus, were exposed to cadmium-spiked estuarine sediment for 28 d to determine effects on mortality, growth, and reproduction relative to interstitial water and SEM/AVS normalization. Seven treatments of cadmium were tested: 0 (control), 0.34, 0.74, 1.31, 1.55, 2.23, and 4.82 M SEM{sub Cd}/AVS ratios (measured concentrations). Interstitial water cadmium (IW{sub Cd}) and sediment concentrations of SEM{sub Cd} and AVS were monitored periodically and by depth during the exposure. When sediment SEM{sub Cd}/AVS ratios were {le} 1.55, mean IW{sub Cd} concentrations were less than the 96-h water-only cadmium LC50 for juvenile and subadult L. plumulosus, and mortality, growth, and reproduction were not affected. When SEM{sub Cd}/AVD ratios were {ge} 2.23, IW{sub Cd} concentrations were more than 100 times greater than the 96-h water-only cadmium LC50, and all amphipods died. These results are consistent with predictions of metal bioavailability from acute tests with metal-spiked sediments, i.e., that sediments with SEM{sub Cd}/AVS ratios < 1 are not toxic, while sediments with SEM{sub Cd}/AVS ratios > 1 may be toxic.

  19. A unique apposition compound eye in the mesopelagic hyperiid amphipod Paraphronima gracilis.

    PubMed

    Baldwin Fergus, Jamie L; Johnsen, Sönke; Osborn, Karen J

    2015-02-16

    The mesopelagic habitat is a vast space that lacks physical landmarks and is structured by depth, light penetration, and horizontal currents. Solar illumination is visible in the upper 1,000 m of the ocean, becoming dimmer and spectrally filtered with depth-generating a nearly monochromatic blue light field. The struggle to perceive dim downwelling light and bioluminescent sources and the need to remain unseen generate contrasting selective pressures on the eyes of mesopelagic inhabitants. Hyperiid amphipods are cosmopolitan members of the mesopelagic fauna with at least ten different eye configurations across the family-ranging from absent eyes in deep-living species to four enlarged eyes in mesopelagic individuals. The hyperiid amphipod Paraphronima gracilis has a pair of bi-lobed apposition compound eyes, each with a large upward-looking portion and a small lateral-looking portion. The most unusual feature of the P. gracilis eye is that its upward-looking portion is resolved into a discontinuous retina with 12 distinct groups, each serving one transverse row of continuously spaced facets. On the basis of eye morphology, we estimated spatial acuity (2.5° ± 0.11°, SEM; n = 25) and optical sensitivity (30 ± 3.4 μm(2) ⋅ sr, SEM; n = 25). Microspectrophotometry showed that spectral sensitivity of the eye peaked at 516 nm (±3.9 nm, SEM; n = 6), significantly offset from the peak of downwelling irradiance in the mesopelagic realm (480 nm). Modeling of spatial summation within the linear retinal groups showed that it boosts sensitivity with less cost to spatial acuity than more typical configurations.

  20. A new family, genus and species of freshwater amphipod Australomicroprotopus megacoxa gen. nov. sp. nov. (Senticaudata, Corophiidea, Microprotopoidea, Australomicroprotopidae fam. nov.) from Australia.

    PubMed

    Myers, Alan A; Lowry, James K; Billingham, Zac

    2016-01-01

    A new species of fresh-water amphipod is described from Australia. Australomicroprotopus megacoxa gen. nov. sp. nov. It is placed in a new family, the Australomicroprotopidae fam. nov. and is fully described and figured. PMID:27615940

  1. Effect of housing and environmental enrichment on adrenocortical activity, behavior and reproductive cyclicity in the female tigrina (Leopardus tigrinus) and margay (Leopardus wiedii).

    PubMed

    Moreira, Nei; Brown, J L; Moraes, W; Swanson, W F; Monteiro-Filho, E L A

    2007-11-01

    The objective of this study was to evaluate the effects of different captive housing conditions on reproductive cyclicity and adrenocortical activity in adult females of two small-sized felid species, the tigrina (Leopardus tigrinus; n = 3) and margay (Leopardus wiedii; n = 2). Females were housed as singletons and subjected to three enclosure conditions over successive time periods: Phase I-large, enriched enclosures for 3 months; Phase II-small, empty enclosures for 5.5 months; Phase III-the same small enclosures enriched with branches and nest boxes for 6.5 months. Fecal samples were collected five times weekly throughout the study for analysis of progestagen, estrogen, and corticoid metabolites. On the basis of observed behaviors, stereotypic pacing was more frequent before feeding for all cats, regardless of enclosure conditions. Both species displayed a bimodal activity pattern, with peaks occurring at nightfall and dawn. All animals exhibited agitated behavior, characterized by a high frequency and duration of stereotypic pacing, primarily during the first 3 days after moving to the small empty enclosures. On the basis of hormonal analyses, ovarian follicular activity decreased and corticoid concentrations increased in tigrinas after transfer to the small barren cages compared to the patterns observed in the initial large, enriched enclosures. Corticoid concentrations in tigrinas then declined after small cage enrichment. Margay females exhibited increased corticoid excretion during Phases II and III, but in contrast to tigrinas, concentrations remained high even after cage enrichment. It was further showed that enriching the small enclosures was insufficient to reestablish normal ovarian activity within the time frame of the study for both species. In summary, margay and tigrina females exhibited distinct elevations in corticoid concentrations after transfer from large enriched enclosures to smaller barren cages that corresponded with agitated behavior

  2. Crystal structure of a blue laccase from Lentinus tigrinus: evidences for intermediates in the molecular oxygen reductive splitting by multicopper oxidases

    PubMed Central

    Ferraroni, Marta; Myasoedova, Nina M; Schmatchenko, Vadim; Leontievsky, Alexey A; Golovleva, Ludmila A; Scozzafava, Andrea; Briganti, Fabrizio

    2007-01-01

    Background Laccases belong to multicopper oxidases, a widespread class of enzymes implicated in many oxidative functions in pathogenesis, immunogenesis and morphogenesis of organisms and in the metabolic turnover of complex organic substances. They catalyze the coupling between the four one-electron oxidations of a broad range of substrates with the four-electron reduction of dioxygen to water. These catalytic processes are made possible by the contemporaneous presence of at least four copper ion sites, classified according to their spectroscopic properties: one type 1 (T1) site where the electrons from the reducing substrates are accepted, one type 2 (T2), and a coupled binuclear type 3 pair (T3) which are assembled in a T2/T3 trinuclear cluster where the electrons are transferred to perform the O2 reduction to H2O. Results The structure of a laccase from the white-rot fungus Lentinus (Panus) tigrinus, a glycoenzyme involved in lignin biodegradation, was solved at 1.5 Å. It reveals a asymmetric unit containing two laccase molecules (A and B). The progressive reduction of the copper ions centers obtained by the long-term exposure of the crystals to the high-intensity X-ray synchrotron beam radiation under aerobic conditions and high pH allowed us to detect two sequential intermediates in the molecular oxygen reduction pathway: the "peroxide" and the "native" intermediates, previously hypothesized through spectroscopic, kinetic and molecular mechanics studies. Specifically the electron-density maps revealed the presence of an end-on bridging, μ-η1:η1 peroxide ion between the two T3 coppers in molecule B, result of a two-electrons reduction, whereas in molecule A an oxo ion bridging the three coppers of the T2/T3 cluster (μ3-oxo bridge) together with an hydroxide ion externally bridging the two T3 copper ions, products of the four-electrons reduction of molecular oxygen, were best modelled. Conclusion This is the first structure of a multicopper oxidase which

  3. Proteasomal activities in the claw muscle tissue of European lobster, Homarus gammarus, during larval development.

    PubMed

    Götze, Sandra; Saborowski, Reinhard

    2011-10-01

    Decapod crustaceans grow discontinuously and gain size through complex molt processes. The molt comprises the loss of the old cuticle and, moreover, substantial reduction and re-organization of muscles and connective tissues. In adult lobsters, the muscle tissue of the massive claws undergoes significant atrophy of 40-75% before ecdysis. The degradation of this tissue is facilitated by calcium-dependent proteases and by the proteasome, an intra-cellular proteolytic multi-enzyme complex. In contrast to the adults, the involvement of the proteasome during the larval development is yet not validated. Therefore, we developed micro-methods to measure the 20S and the 26S proteasomal activities within mg- and sub-mg-quantities of the larval claw tissue of the European lobster, Homarus gammarus. Within the three larval stages (Z1-3) we distinguished between sub-stages of freshly molted/hatched (post-molt), inter-molt, and ready to molt (pre-molt) larvae. Juveniles were analyzed in the post-molt and in the inter-molt stage. The trypsin-like, the chymotrypsin-like, and the peptidyl-glutamyl peptide hydrolase activity (PGPH) of the 20S proteasome increased distinctly from freshly hatched larvae to pre-molt Z1. During the Z2 stage, the activities were highest in the post-molt animals, decreased in the inter-molt animals and increased again in the pre-molt animals. A similar but less distinct trend was evident in the Z3 stages. In the juveniles, the proteasomal activities decreased toward the lowest values. A similar pattern was present for the chymotrypsin-like activity of the 26S proteasome. The results show that the proteasome plays a significant role during the larval development of lobsters. This is not only reflected by the elevated activities, but also by the continuous change of the trypsin/chymotrypsin-ratio which may indicate a shift in the subunit composition of the proteasome and, thus, a biochemical adjustment to better cope with elevated protein turnover rates

  4. Response of Gammarus pulex and Baetis rhodani to springtime acid episodes in humic brooks.

    PubMed

    Andrén, C M; Eriksson Wiklund, A-K

    2013-10-01

    While chronic acidification of water bodies has been steadily decreasing, episodic acidification continues to affect stream biology by temporarily decreasing pH and mobilizing aluminum. These events are becoming more common as climate change renders more frequent and intense storms and flooding. Throughout Scandinavia, the effects of acidification have been mitigated by liming since the 1980s, but remediation efforts can now be reduced. While transient acidity may reduce fish populations, also other species in streams are affected. In this in-stream study, two macro-invertebrates (Gammarus pulex and Baetis rhodani), both known as salmonid prey organisms, were exposed to snowmelt in six humic brooks with a natural gradient of pH and inorganic monomeric Al (Al(i)). We hypothesize that acid toxicity thresholds can be defined using lethal (mortality) and sublethal (changes in body elemental content) metrics. Periodic observations were made of mortality and whole body concentrations of base cations (BC: Ca, Mg, Na and K) and metals (Al, Fe, Zn and Mn). Mortality increased dramatically at pH<6.0 and Al(i)>15 μg/L for G. pulex and at pH<5.7 and Al(i)>20 μg/L for B. rhodani. No accumulation of Al was found. The invertebrate body Na concentration decreased when pH dropped, suggesting that osmoregulation in both species was affected. In contrast to general BC pattern, Ca concentration in G. pulex and Mg concentration in B. rhodani increased when pH decreased. Although Al(i) strongly correlates to pH, the Al composition of soil and bedrock also influences Al availability, potentially contributing to toxic Al(i) episodes. The estimated values calculated in this study can be used to improve water quality criteria and as thresholds to adjust doses of lime compared to old recommendations in ongoing liming programs. Such adjustments may be critical since both Al(i) and pH levels have to be balanced to mitigate damage to recovering stream ecosystems.

  5. A comparison of the short-term toxicity of cadmium to indigenous and alien gammarid species.

    PubMed

    Boets, Pieter; Lock, Koen; Goethals, Peter L M; Janssen, Colin R; De Schamphelaere, Karel A C

    2012-05-01

    Amphipods play an important role in many aquatic ecosystems and are commonly used in ecotoxicology and ecosystem health assessment. Several alien gammarids have been introduced in many regions of the world during the last decades. In this study, we investigated if differences in cadmium sensitivity occurred between (1) different species belonging to the family Gammaridae and (2) different populations of the same species originating from a polluted or a non-polluted site. The acute cadmium toxicity to two indigenous (Gammarus pulex and Gammarus fossarum) and four alien (Dikerogammarus villosus, Echinogammarus berilloni, Gammarus roeseli and Gammarus tigrinus) gammarids occurring in Belgium was tested. Significant differences (P < 0.05) in median lethal concentrations (LC(50)) were found between the different species, with 72 h-LC50s ranging from 6.3 to 268 μg/l and 96 h-LC50s from 4.7 to 88.9 μg/l. No clear trend in Cd sensitivity was found when comparing indigenous and alien gammarids. D. villosus, an alien invasive species, was the most sensitive to Cd toxicity and E. berilloni, another alien species, the least sensitive. In addition, larger Gammarid species were more sensitive to Cd toxicity than smaller ones. No significant differences were found between populations of the same species originating from metal polluted sites or non-polluted sites. Overall, our results showed that considerable differences in Cd sensitivity exist between gammarid species, which should be taken into consideration in environmental risk assessment and water quality standard setting. Finally, our data suggest that alien gammarids would not have an advantage over indigenous gammarids in Cd contaminated environments.

  6. Evaluation of ability of reference toxicity tests to identify stress in laboratory populations of the amphipod Hyalella azteca

    USGS Publications Warehouse

    McNulty, E.W.; Dwyer, F.J.; Ellersieck, Mark R.; Greer, E.I.; Ingersoll, C.G.; Rabeni, C.F.

    1999-01-01

    Standard methods for conducting toxicity tests imply that the condition of test organisms can be established using reference toxicity tests. However, only a limited number of studies have evaluated whether reference toxicity tests can actually be used to determine if organisms are in good condition at the start of a test. We evaluated the ability of reference toxicants to identify stress associated with starvation in laboratory populations of the amphipod Hyalella azteca using acute toxicity tests and four reference toxicants: KCl, CdCl2, sodium pentachlorophenate (NaPCP), and carbaryl. Stress associated with severe starvation was observed with exposure of amphipods to carbaryl or NaPCP but not with exposure to KCl or CdCl2 (i.e., lower LC50 with severe starvation). Although the LC50s for NaPCP and carbaryl were statistically different between starved and fed amphipods, this difference may not be biologically significant given the variability expected in acute lethality tests. Stress associated with sieving, heat shock, or cold shock of amphipods before the start of a test was not evident with exposure to carbaryl or KCl as reference toxicants. The chemicals evaluated in this study provided minimal information about the condition of the organisms used to start a toxicity test. Laboratories should periodically perform reference toxicity tests to assess the sensitivity of life stages or strains of test organisms. However, use of other test acceptability criteria required in standard methods such as minimum survival, growth, or reproduction of organisms in the control treatment at the end of a test, provides more useful information about the condition of organisms used to start a test compared to data generated from reference toxicity tests.

  7. Evaluation of ability of reference toxicity tests to identify stress in laboratory populations of the amphipod Hyalella azteca

    SciTech Connect

    McNulty, E.W.; Ellersieck, M.R.; Rabeni, C.F.; Dwyer, F.J.; Greer, E.I.; Ingersoll, C.G.

    1999-03-01

    Standard methods for conducting toxicity tests imply that the condition of test organisms can be established using reference toxicity tests. However, only a limited number of studies have evaluated whether reference toxicity tests can actually be used to determine if organisms are in good condition, at the start of a test. The authors evaluated the ability of reference toxicants to identify stress associated with starvation in laboratory populations of the amphipod Hyalella azteca using acute toxicity tests and four reference toxicants: KCl, CdCl{sub 2}, sodium pentachlorophenate (NaPCP), and carbaryl. Stress associated with severe starvation was observed with exposure of amphipods to carbaryl or NaPCP but not with exposure to KCl or CdCl{sub 2} (i.e., lower LC50 with severe starvation). Although the LC50s for NaPCP and carbaryl were statistically different between starved and fed amphipods, this difference may not be biologically significant given the variability expected in acute lethality tests. Stress associated with sieving, heat shock, or cold shock of amphipods before the start of a test was not evident with exposure to carbaryl or KCl as reference toxicants. The chemicals evaluated in this study provided minimal information about the condition of the organisms used to start a toxicity test. Laboratories should periodically perform reference toxicity tests to assess the sensitivity of life stages or strains of test organisms. However, use of other test acceptability criteria required in standard methods, such as minimum survival, growth, or reproduction of organisms in the control treatment at the end of a test, provides more useful information about the condition of organisms used to start a test compared to data generated from reference toxicity tests.

  8. Use of Gammarus pulex (L. ) in safety evaluation tests: culture and selection of a sensitive life stage

    SciTech Connect

    McCahon, C.P.; Pascoe, D.

    1988-06-01

    A simple and effective method for the laboratory culture of Gammarus pulex is described. Over 70% of juveniles survived, reaching sexual maturity within 130 days at 13 degrees C, and animals of different ages were available for toxicity tests throughout the year. The acute toxicity of cadmium to cultured animals of several known ages and to field-collected animals of unknown age was determined. Juveniles (1 day old, 48 hr LC50 0.019 mg Cd liter-1) were found to be almost 250 times more sensitive than the oldest age group tested (220 days old, 48 hr LC50 4.7 mg Cd liter-1). In view of its ease of culture and sensitivity to pollutants, it is proposed that G. pulex should be more widely employed as a standard toxicity test species in the hazard evaluation process.

  9. The impact of gypsum mine water: a case study on morphology and DNA integrity in the freshwater invertebrate, Gammarus balcanicus.

    PubMed

    Ternjej, Ivančica; Mihaljević, Zlatko; Ivković, Marija; Previšić, Ana; Stanković, Igor; Maldini, Krešimir; Želježić, Davor; Kopjar, Nevenka

    2014-06-01

    The aim of our study was to investigate how exposure to heavy metal-rich waters from gypsum mining affects the morphology and levels of primary DNA damage in Gammarus balcanicus. Chemical analysis revealed increased concentrations of metals in water and sediment collected at a site impacted by gypsum mine wastewaters. The specimens also showed elevated total tissue metal levels when compared with the organisms collected at the reference site. The most prominent increase was observed for strontium, followed by iron, nickel, vanadium, aluminium, and manganese. The major pathway of entry for these toxic substances was through the degraded exoskeleton as a consequence of excessive strontium input (unbalanced calcium/strontium ratio) and altered permeability. Disturbed exoskeleton integrity was observed only in individuals collected downstream of the gypsum mine, which was confirmed by electron microscopy. Levels of primary DNA damage were evaluated using the alkaline comet assay in the haemolymph of the specimens. PMID:24682074

  10. A model for the bioaccumulation of (99)Tc in lobsters (Homarus gammarus) from the West Cumbrian coast.

    PubMed

    Olsen, Y S; Vives i Batlle, J

    2003-01-01

    A biokinetic model is presented that simulates the uptake and release of (99)Tc by the European lobster (Homarus gammarus). This organism is of significant radioecological interest since lobsters, in contrast to most other organisms, have a high affinity for (99)Tc. The model is designed to represent annually averaged (99)Tc concentrations in lobsters from the Cumbrian coast, where significant levels of (99)Tc have been released under authorisation by the nuclear fuel reprocessing plant at BNFL Sellafield. This paper describes the construction of the model, how it was calibrated using data from published literature, and preliminary results indicating that model output agrees well with the available monitoring data. Given that this model successfully combines laboratory and field data, this research could potentially make a significant contribution to the field, as, to date, it has been difficult to predict and explain concentrations of (99)Tc in lobsters. PMID:12691720

  11. In vitro cytotoxicity of crustacean immunostimulants for lobster (Homarus gammarus) granulocytes demonstrated using the neutral red uptake assay.

    PubMed

    Hauton, Chris; Smith, Valerie J

    2004-07-01

    The neutral red uptake (NRU) cell viability assay was adapted for use with lobster Homarus gammarus (Linnaeus, 1758) granulocytes cultured in vitro. The assay was more sensitive than the conventional trypan blue exclusion assay and facilitated a higher sample throughput than subjective microscope-based assessments of cell viability. The NRU assay was demonstrated to have a linear response from 470 to at least 126000 cells cm(-2). It was used to investigate the acute cytotoxicity of three commercial and two candidate crustacean aquaculture immunostimulants on lobster granulocytes. All five stimulants had a cytotoxic action on the granulocytes and the toxic dose for some of these stimulants was found to be below their commercially prescribed dose. The long term energetic cost of the use of these stimulants and the concomitant potential for a reduction in growth rate of cultured decapod crustaceans, which is fundamental to the success of commercial aquaculture, is identified and discussed. PMID:15145418

  12. Effect of the copepod parasite Nicothoë astaci on haemolymph chemistry of the European lobster Homarus gammarus.

    PubMed

    Davies, Charlotte E; Vogan, Claire L; Rowley, Andrew F

    2015-03-01

    The gills of the European lobster Homarus gammarus (L.) are susceptible to parasitization by the copepod Nicothoë astaci, the lobster louse. This copepod feeds on haemolymph of the host and can damage the gills, potentially affecting gaseous exchange capabilities. To investigate the host response to the parasite, haemolymph levels of total protein, haemocyanin, glucose and ammonia were quantified in adult lobsters carrying varying parasite loads. Parasite loads correlated positively with total haemolymph protein and haemocyanin concentrations but not with glucose or ammonia concentrations. The data suggest that lobsters with gills damaged by the feeding activities of N. astaci respond by producing higher levels of haemocyanin, which is both a key defence response and may compensate for their decreased respiratory functioning.

  13. Effect of the copepod parasite Nicothoë astaci on haemolymph chemistry of the European lobster Homarus gammarus.

    PubMed

    Davies, Charlotte E; Vogan, Claire L; Rowley, Andrew F

    2015-03-01

    The gills of the European lobster Homarus gammarus (L.) are susceptible to parasitization by the copepod Nicothoë astaci, the lobster louse. This copepod feeds on haemolymph of the host and can damage the gills, potentially affecting gaseous exchange capabilities. To investigate the host response to the parasite, haemolymph levels of total protein, haemocyanin, glucose and ammonia were quantified in adult lobsters carrying varying parasite loads. Parasite loads correlated positively with total haemolymph protein and haemocyanin concentrations but not with glucose or ammonia concentrations. The data suggest that lobsters with gills damaged by the feeding activities of N. astaci respond by producing higher levels of haemocyanin, which is both a key defence response and may compensate for their decreased respiratory functioning. PMID:25751860

  14. Specific antioxidant reactions to oxidative stress promoted by natural organic matter in two amphipod species from Lake Baikal.

    PubMed

    Timofeyev, Maxim A; Shatilina, Zhanna M; Kolesnichenko, Aleksey V; Kolesnichenko, Viktoria V; Steinberg, Christian E W

    2006-04-01

    Aquatic organisms are exposed to a variety of natural chemical stressors such as humic substances. The aim of this study was to investigate the mode of action of natural organic matter (NOM, roughly 80% of which is humic substances) on two freshwater amphipods from Lake Baikal, Eulimnogammarus verrucosus (Gerstf.) and Eulimnogammarus cyaneus (Dyb.), in order to assess the potential oxidative stress of NOM impact. Chosen as oxidative stress markers were lipid peroxidation and cell internal hydrogen peroxide level as well as peroxidase, catalase, and glutathione S-transferase activities. Exposure of amphipods to NOM caused a significant increase in lipid peroxidation but a concomitant decrease in hydrogen peroxide concentration, and peroxidase and (to a lesser degree) glutathione S-transferase activities. An interim increase of catalase activity was observed. A possible reason for the decrease in major antioxidant enzyme activity is exhaustion of the reservoir of reduced substrates in the first stage of the antioxidant defense reaction. Despite the inhibition of major antioxidant enzymes, the studied amphipods were able to successfully resist the NOM oxidative impact and, at low NOM concentrations, to combat lipid peroxidation processes. PMID:16528684

  15. Comparison of marine sediment toxicity test protocols for the amphipod Rhepoxynius abronius and the polychaete worm Nereis (Neanthes) arenaceodentata

    SciTech Connect

    Anderson, B.S.; Hunt, J.W.; Phillips, B.M. |

    1998-05-01

    The 10-d amphipod survival toxicity test protocol using Rhepoxynius abronius was compared to the 20-d polychaete worm growth and survival protocol using Nereis (Neanthes) arenaceodentata. Of the 341 sediment samples collected in California and tested over a 2-year period. 78% significantly inhibited R. abronius survival, whereas 2 and 26% significantly inhibited N. arenaceodentata survival and biomass, respectively. Statistical power associated with each protocol endpoint was determined by calculating the minimum significant difference (MSD) for each test protocol for this data set. The 90th percentile MSDs for R. abronius survival and N. arenaceodentata survival and biomass were 16, 36, and 56%, respectively. Survival of R. abronius was significantly negatively correlated with a number of toxicants including metals, pesticides, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls. No significant correlations were determined between N. arenaceodentata survival or biomass and contaminants measured. Amphipod survival was also negatively correlated with sediment total organic carbon and grain size, but when samples with a high percent fine grain size (>90% fines) were eliminated from consideration, the overall conclusions of the study were not altered. The 10-d amphipod survival protocol using R. abronius was a more sensitive indicator of toxicity, but the results indicate that this was due to greater statistical power rather than greater sensitivity of the test organisms or endpoints.

  16. Bioavailability of particle-associated silver, cadmium, and zinc to the estuarine amphipod Leptocheirus plumulosus through dietary ingestion

    USGS Publications Warehouse

    Schlekat, C.E.; Decho, Alan W.; Chandler, G.T.

    2000-01-01

    We conducted experiments to determine effects of particle type on assimilatory metal bioavailability to Leptocheirus plumulosus, an infaunal, estuarine amphipod that is commonly used in sediment toxicity tests. The following particles were used to represent natural food items encountered by this surface-deposit and suspension-feeding amphipod: bacterial exopolymeric sediment coatings, polymeric coatings made from Spartina alterniflora extract, amorphous iron oxide coatings, the diatom Phaeodactylum tricornutum, the chlorophyte Dunaliella tertiolecta, processed estuarine sediment, and fresh estuarine sediment. Bioavailability of the gamma-emitting radioisotopes 110mAg, 109Cd, and 65Zn was measured as the efficiency with which L. plumulosus assimilated metals from particles using pulse-chase methods. Ag and Cd assimilation efficiencies were highest from bacterial exopolymeric coatings. Zn assimilation efficiency exhibited considerable interexperimental variation; the highest Zn assimilation efficiencies were measured from phytoplankton and processed sediment. In general, Ag and Cd assimilation efficiencies from phytoplankton were low and not related to the proportion of metal associated with cell cytosol or cytoplasm, a phenomenon reported for other particle-ingesting invertebrates. Amphipod digestive processes explain differences in Ag and Cd assimilation efficiencies between exopolymeric coatings and phytoplankton. Results highlight the importance of labile polymeric organic carbon sediment coatings in dietary metals uptake by this benthic invertebrate, rather than recalcitrant organic carbon, mineralogical features such as iron oxides, or phytoplankton.

  17. Comprehensive analysis of Hox gene expression in the amphipod crustacean Parhyale hawaiensis.

    PubMed

    Serano, Julia M; Martin, Arnaud; Liubicich, Danielle M; Jarvis, Erin; Bruce, Heather S; La, Konnor; Browne, William E; Grimwood, Jane; Patel, Nipam H

    2016-01-01

    Hox genes play crucial roles in establishing regional identity along the anterior-posterior axis in bilaterian animals, and have been implicated in generating morphological diversity throughout evolution. Here we report the identification, expression, and initial genomic characterization of the complete set of Hox genes from the amphipod crustacean Parhyale hawaiensis. Parhyale is an emerging model system that is amenable to experimental manipulations and evolutionary comparisons among the arthropods. Our analyses indicate that the Parhyale genome contains a single copy of each canonical Hox gene with the exception of fushi tarazu, and preliminary mapping suggests that at least some of these genes are clustered together in the genome. With few exceptions, Parhyale Hox genes exhibit both temporal and spatial colinearity, and expression boundaries correlate with morphological differences between segments and their associated appendages. This work represents the most comprehensive analysis of Hox gene expression in a crustacean to date, and provides a foundation for functional studies aimed at elucidating the role of Hox genes in arthropod development and evolution.

  18. Effects of storage on the toxicity of sediments spiked with fluoranthene to the amphipod, Rhepoxynius abronius

    SciTech Connect

    Cole, F.A.; Boese, B.L.; Swartz, R.C.; Lamberson, J.O.; DeWitt, T.H.

    2000-03-01

    To determine the effect of storage on contaminant bioavailability and toxicity, two sediment types, a fine sand and a silty sand, were spiked with nine concentrations of fluoranthene, then stored at 4 C for up to 170 d. Toxicity of the stored sediment was determined eight times during this storage interval using standard 10-d toxicity tests with the marine infaunal amphipod Rhepoxynius abronius. The concentrations of fluoranthene in the sediment and interstitial water were determined on samples taken on each test date. The toxicity of fluoranthene in the silty sand was similar for all storage times with LC50s ranging from 5.3 to 6.6 mg/g organic carbon (OC). The LC50 in the fine sand was 7.4 mg/g OC after 13 d of storage, ranged from 10.2 to 11.8 mg/g OC during 27 to 83 d of storage, and increased to 24.2 and 27.6 mg/g OC after 121 and 170 d of storage, respectively. These data indicate that the toxicity of both the fine and the silty sand remained essentially constant during storage from days 27 to 83. Toxicity tests conducted before or after that period may give misleading results because of disequilibrium or unknown storage effects.

  19. Analysis of bacterial communities associated with the benthic amphipod Diporeia in the Laurentian Great Lakes Basin.

    PubMed

    Winters, Andrew D; Marsh, Terence L; Brenden, Travis O; Faisal, Mohamed

    2015-01-01

    Bacterial communities play important roles in the biological functioning of crustaceans, yet little is known about their diversity, structure, and dynamics. This study was conducted to investigate the bacterial communities associated with the benthic amphipod Diporeia, an important component in the Great Lakes foodweb that has been declining over the past 3 decades. In this study, the combination of 16S rRNA gene sequencing and terminal restriction fragment length polymorphism revealed a total of 175 and 138 terminal restriction fragments (T-RFs) in Diporeia samples following treatment with the endonucleases HhaI and MspI, respectively. Relatively abundant and prevalent T-RFs were affiliated with the genera Flavobacterium and Pseudomonas and the class Betaproteobacteria. T-RFs affiliated with the order Rickettsiales were also detected. A significant difference in T-RF presence and abundance (P = 0.035) was detected among profiles generated for Diporeia collected from 4 sites in Lake Michigan. Comparison of profiles generated for Diporeia samples collected in 2 years from lakes Superior and Michigan showed a significant change in diversity for Lake Superior Diporeia but not Lake Michigan Diporeia. Profiles from one Lake Michigan site contained multiple unique T-RFs compared with other Lake Michigan Diporeia profiles, most notably one that represents the genus Methylotenera. This study generated the most extensive list of bacteria associated with Diporeia and sheds useful insights on the microbiome of Great Lakes Diporeia that may help to reveal potential causes of the decline of Diporeia populations.

  20. Sex-dependent effects of ultraviolet radiation on the marine amphipod Ampithoe valida (Ampithoidae).

    PubMed

    Valiñas, Macarena S; Helbling, E Walter

    2015-06-01

    The combined effects of solar radiation and diet on the marine amphipod Ampithoe valida were investigated exposing individuals to two solar radiation treatments: PAB (>280 nm, PAR+UV-A+UV-B) and P (>400 nm, only PAR), and three diets: poor (Ulva rigida) and rich (Porphyra columbina) in UV-absorbing compounds (UVAC), and mixed diet: (U. rigida+P. columbina). Females of A. valida showed higher food consumption rates when diets contained P. columbina, and preferred this macroalgae rather than U. rigida, resulting in a higher content of UVAC in their bodies. Moreover, the content of UVAC increased in the PAB treatment, thus suggesting the existence of a mechanism to accumulate these compounds under UVR. Although UVR affected the survival, the highest mortality rates were found in those females fed with poor-UVAC diets, which evidence that UVAC provided partial protection against UVR. Males preferred mixed diet, and did not show preference for any particular macroalgae. No differences in mortality were observed between radiation treatments, indicating that UVR did not affect the survival of males, independently if they accumulated UVAC or not. The vulnerability of females to UVR would be partially determined by the type of food consumed, which in turn would be closely related to the macroalgae composition of the intertidal they inhabiting. These effects could be even more pronounced under a global change scenario. PMID:25867457

  1. Axogenesis in the central and peripheral nervous system of the amphipod crustacean Orchestia cavimana.

    PubMed

    Ungerer, Petra; Geppert, Maria; Wolff, Carsten

    2011-03-01

    We describe the formation of the major axon pathways in the embryonic central and peripheral nervous systems of the amphipod crustacean Orchestia cavimana Heller, 1865 by means of antibody staining against acetylated alpha-tubulin. The data add to a long list of previous studies of various other aspects of development in Orchestia and provide a basis for future studies of neurogenesis on a deeper cellular and molecular level. Orchestia exhibits a tripartite dorsal brain, which is a characteristic feature of euarthropods. Its anlagen are the first detectable structures in the developing nervous system and can be traced back to distinct neuronal cell clusters in the early embryo. The development of the ventral nervous system proceeds with an anteroposterior gradient of development. In each trunk segment, the longitudinal connectives and the anterior commissure form first, followed by the intersegmental nerve, the posterior commissure and segmental nerves, respectively. A single commissure of a vestigial seventh pleonal segment is found. In the peripheral nervous system we observe a spatial and temporal pattern of leg innervation, which is strikingly similar in both limb types, the uniramous pereopods and the biramous pleopods. A proximal leg nerve splitting distally into two separated nerves probably reflects a general feature of crustaceans.

  2. Uptake, biotransformation, and elimination of benzo[a]pyrene by the gammarid amphipod, Leptocheirus plumulosus

    SciTech Connect

    Dickbut, R.M.; Huszai, C.M.; Lay, P.W.; Schaffner, L.C.

    1995-12-31

    The uptake, biotransformation, and elimination of {sup 3}H-benzo[a]pyrene (B[a]P) by the gammarid amphipod Leptocheirus plumulosus was evaluated in laboratory exposures. Rapid uptake (i.e. within 2.5 h) of sediment-associated B[a]P was observed, and during the exposures organism body burdens were dominated by organic extractable (e.g. parent compound) components, with aqueous soluble and bound metabolites constituting a much smaller fraction of the total body burden. However, upon discontinuation of exposure of the organisms to B[a]P, organic extractable compounds were more rapidly eliminated by L. plumulosus than the aqueous extractable and bound contaminant pools. Uptake and elimination of B[a]P were adequately modeled assuming first order kinetics, with the exception of the early stages of exposure. The rapid uptake during the first few hours of exposure of Leptocheirus to sediment-associated B[a]P may be due to sorption of B[a]P to the exoskeleton of the organism. This hypothesis is under further investigation. Uptake and elimination of B[a]P metabolite pools by L. plumulosus was best modeled assuming a fraction of the metabolite pool was irreversibly bound or slowly eliminated.

  3. Identification of a putative germ plasm in the amphipod Parhyale hawaiensis

    PubMed Central

    2013-01-01

    Background Specification of the germ line is an essential event during the embryonic development of sexually reproducing animals, as germ line cells are uniquely capable of giving rise to the next generation. Animal germ cells arise through either inheritance of a specialized, maternally supplied cytoplasm called 'germ plasm’ or though inductive signaling by somatic cells. Our understanding of germ cell determination is based largely on a small number of model organisms. To better understand the evolution of germ cell specification, we are investigating this process in the amphipod crustacean Parhyale hawaiensis. Experimental evidence from previous studies demonstrated that Parhyale germ cells are specified through inheritance of a maternally supplied cytoplasmic determinant; however, this determinant has not been identified. Results Here we show that the one-cell stage Parhyale embryo has a distinct cytoplasmic region that can be identified by morphology as well as the localization of germ line-associated RNAs. Removal of this cytoplasmic region results in a loss of embryonic germ cells, supporting the hypothesis that it is required for specification of the germ line. Surprisingly, we found that removal of this distinct cytoplasm also results in aberrant somatic cell behaviors, as embryos fail to gastrulate. Conclusions Parhyale hawaiensis embryos have a specialized cytoplasm that is required for specification of the germ line. Our data provide the first functional evidence of a putative germ plasm in a crustacean and provide the basis for comparative functional analysis of germ plasm formation within non-insect arthropods. PMID:24314239

  4. Chronic toxicity of 2,4,6-trinitrotoluene to a marine polychaete and an estuarine amphipod

    SciTech Connect

    Green, A.; Moore, D.; Farrar, D.

    1999-08-01

    The chronic toxicity of sediment-associated 2,4,6-trinitrotoluene (TNT) to the marine polychaete Neanthes arenaceodentata and the estuarine amphipod Leptocheirus plumulosus was evaluated. Test organisms were exposed to sediments spiked with radiolabeled TNT for 28 d, after which time the endpoints of mortality, growth, and reproduction (L. plumulosus only) were assayed and compared against the TNT tissue concentrations as well as the TNT sediment concentrations. Survival was significantly reduced at a tissue concentration of 61 {micro}g TNT/g wet wt tissue in N. arenaceodentata and L. plumulosus with enhancement (significant for N. arenaceodentata) occurring at the lower TNT concentrations. Growth was significantly reduced at the highest TNT exposure of 10.0 {micro}g TNT/g wet wt tissue in L. plumulosus. Reproduction was significantly reduced at a tissue concentration of 6.3 {micro}g TNT/g wet wt tissue in L. plumulosus. The results of this study demonstrate that both N. arenaceodentata and L. plumulosus are sensitive to the presence of sediment-associated TNT and that more information is needed about the toxicity of TNT to benthic fauna to facilitate risk assessment and management of TNT-contaminated sites.

  5. Molecular evidence of the survival of subterranean amphipods (Arthropoda) during Ice Age underneath glaciers in Iceland.

    PubMed

    Kornobis, Etienne; Pálsson, Snaebjörn; Kristjánsson, Bjarni K; Svavarsson, Jörundur

    2010-06-01

    A Two endemic groundwater arthropod crustacean species, Crangonyx islandicus and Crymostygius thingvallensis, were recently discovered on the mid-Atlantic volcanic island of Iceland. The extent of morphological differences from closest relatives, endemism, along with the geographic isolation of Iceland and its complete coverage by glaciers 21,000 years ago, suggests that these two species have survived glaciation periods in sub-glacial refugia. Here we provide strong support for this hypothesis by an analysis of mitochondrial genetic variation within Crangonyx islandicus. Our results show that the species is divided into several distinct monophyletic groups that are found along the volcanic zone in Iceland, which have been separated by 0.5 to around 5 million years. The genetic divergence between groups reflects geographic distances between sampling sites, indicating that divergence occurred after the colonization of Iceland. The genetic patterns, as well as the dependency of genetic variation on distances from the tectonic plate boundary and altitude, points to recent expansion from several refugia within Iceland. This presents the first genetic evidence of multicellular organisms as complex as crustacean amphipods which have survived glaciations beneath an ice sheet. This survival may be explained by geothermal heat linked to volcanic activities, which may have maintained favourable habitats in fissures along the tectonic plate boundary in Iceland during glaciations.

  6. Response of the phoxocephalid amphipod, Rhepoxynius abronius, to a small oil spill in Yaquina Bay, Oregon

    SciTech Connect

    Kemp, P.F.; Swartz, R.C.; Lamberson, J.O.

    1986-01-01

    A spill of approximately 284,000 liters of Bunker C and diesel fuel oils occurred at the entrance of Yaquina Bay, Oregon, following the wreck of the freighter Blue Magpie on 19 November 1983. A portion of the oil entered the lower estuary and was deposited on subtidal benthic habitats occupied by the phoxocephalid amphipod Rhepoxynius abronius. The species is particularly sensitive to contaminants in sediment and its life history had previously been studied at the same sites affected by the spill. The oil was initially present as small, sand-coated globules at the study site, and persisted in association with detritus and sediment for months. Bioassays with Rhepoxynius abronius showed that the oil globules were not acutely toxic unless mixed into the sediment at concentrations of 1.0 parts per thousand or greater. A series of 10-d bioassays before and after the spill showed that sediment collected from oiled subtidal sites did not become acutely toxic to the species.

  7. Effects of predation and oxygen deficiency on different age classes of the amphipod Monoporeia affinis

    NASA Astrophysics Data System (ADS)

    Sandberg, E.; Bonsdorff, E.

    1996-06-01

    Predation by the big brackish-water isopod Saduria entomon on two age-classes (juveniles and adults) of the small deposit-feeding amphipod Monoporeia (syn. Pontoporeia) affinis was studied at different oxygen conditions (normoxia>11 mg/l O 2, and moderate hypoxia 4 mg/l O 2). Vulnerability of juvenile and adult M. affinis was studied in single and mixed age-class treatments. The proportions of juveniles and adults were varied at one total numerical density. The predatory effects were measured as numbers of individuals consumed and of total biomass intake (mg ash-free dry weight). The highest predation rate (in numbers) was detected in the single-prey treatment with juvenile M. affinis, both in normoxia and moderate hypoxia. No preference for any of the two size classes was found in the treatment with equal numbers of adults and juveniles. In normoxia, the total number of prey consumed decreased with increasing proportions of adults, while intake increased in terms of biomass. In moderate hypoxia, high proportions of adults reduced the predation rate of S. entomon to such an extent that also the intake in terms of biomass was significantly negatively affected.

  8. Sequential developmental acquisition of cotransmitters in identified sensory neurons of the stomatogastric nervous system of the lobsters, Homarus americanus and Homarus gammarus.

    PubMed

    Kilman, V; Fénelon, V S; Richards, K S; Thirumalai, V; Meyrand, P; Marder, E

    1999-06-01

    We studied the developmental acquisition of three of the cotransmitters found in the gastropyloric receptor (GPR) neurons of the stomatogastric nervous systems of the lobsters Homarus americanus and Homarus gammarus. By using wholemount immunocytochemistry and confocal microscopy, we examined the distribution of serotonin-like, allatostatin-like, and FLRF(NH2)-like immunoreactivities within the stomatogastric nervous system of embryonic, larval, juvenile, and adult animals. The GPR neurons are peripheral sensory neurons that send proprioceptive information to the stomatogastric and commissural ganglia. In H. americanus, GPR neurons of the adult contain serotonin-like, allatostatin-like, and Phe-Leu-Arg-Phe-amide (FLRF(NH2))-like immunoreactivities. In the stomatogastric ganglion (STG) of the adult H. americanus and H. gammarus, all of the serotonin-like and allatostatin-like immunoreactivity colocalizes in neuropil processes that are derived exclusively from ramifications of the GPR neurons. In both species, FLRF(NH2)-like immunoreactivity was detected in the STG neuropil by 50% of embryonic development (E50). Allatostatin-like immunoreactivity was visible first in the STG at approximately E70-E80. In contrast, serotonin staining was not clearly visible until larval stage I (LI) in H. gammarus and until LII or LIII in H. americanus. These data indicate that there is a sequential acquisition of the cotransmitters of the GPR neurons. PMID:10340509

  9. Limited prevalence of gaffkaemia (Aerococcus viridans var. homari) isolated from wild-caught European lobsters Homarus gammarus in England and Wales.

    PubMed

    Stebbing, P D; Pond, M J; Peeler, E; Small, H J; Greenwood, S J; Verner-Jeffreys, D

    2012-08-27

    Gaffkaemia, caused by Aerococcus viridans var. homari, causes fatal infections in Homarus spp. (clawed lobsters). Despite its high economic significance to the lobster fisheries in the USA and northern Europe, data on its prevalence in captured and wild populations, particularly in Europe, is scarce. Following an outbreak of gaffkaemia in a European lobster holding facility in South Wales (UK), a base-line survey was conducted for gaffkaemia in wild populations of European lobster Homarus gammarus around the coast of England and Wales. In addition, isolates recovered from the original outbreak and the survey were typed using pulsed-field gel electrophoresis (PFGE) and compared with previously characterised isolates from the USA, UK and Canada. Locally caught H. gammarus were sampled at 30 sites from around the coast of England and Wales between March 2006 and October 2008. Results confirmed that the prevalence of gaffkaemia in populations of H. gammarus was low, with only 9 positive isolates recovered from 952 samples examined. PFGE analysis showed that the isolates from the outbreak investigation shared the same pulsotype as A. viridans var. homari isolates from the USA, Norway and Canada, as well as an isolate (NCIMB 1119) reportedly recovered from an outbreak of European lobsters in England in the 1960s. This confirms earlier studies that suggest virulent strains of A. viridans var. homari show very limited geographical or temporal genetic variation and were introduced into the UK with American lobsters H. americanus. PMID:23186703

  10. Genotoxic effects of the water-soluble fraction of heavy oil in the brackish/freshwater amphipod Quadrivisio aff. lutzi (Gammaridea) as assessed using the comet assay.

    PubMed

    Weber, Laura; Carvalho, Ligia; Sá, Natália; Silva, Viviane; Beraldini, Nathalia; Souza, Valderes; Conceição, Moisés

    2013-05-01

    Amphipod crustaceans have been widely used as invertebrate models in ecotoxicology due to their importance in the food chain. However, few studies have evaluated the genotoxic effects of pollutants in this model using the comet assay. The main obstacle to using amphipods in the comet assay is the difficulty in obtaining enough blood cells from a single individual. In this study, we evaluated the genotoxic effects of the water-soluble fraction (WSF) of heavy oil on the brackish/freshwater amphipod Quadrivisio aff. lutzi, which is common in the coastal lagoons of southeastern Brazil, using hemocytes obtained from single amphipods (without pooling) after optimizing hemolymph extraction. The comet assay revealed significantly higher DNA damage levels (2- to 6-fold higher) in treated amphipods compared to untreated ones with a sublethal concentration of 17.6 % of the WSF within 72 h of treatment. Two independent experiments confirmed an "up and down" pattern of DNA damage, measured as the % of DNA contained in the tail of the comets. Elevations in DNA damage levels were observed at the 6 and 48 h time points, while very low levels of DNA damage were observed at the 24 and 72 h time points. Furthermore, the comet assay revealed gender variability in the levels of DNA damage after short-term exposure. PMID:23479060

  11. Genotoxic effects of the water-soluble fraction of heavy oil in the brackish/freshwater amphipod Quadrivisio aff. lutzi (Gammaridea) as assessed using the comet assay.

    PubMed

    Weber, Laura; Carvalho, Ligia; Sá, Natália; Silva, Viviane; Beraldini, Nathalia; Souza, Valderes; Conceição, Moisés

    2013-05-01

    Amphipod crustaceans have been widely used as invertebrate models in ecotoxicology due to their importance in the food chain. However, few studies have evaluated the genotoxic effects of pollutants in this model using the comet assay. The main obstacle to using amphipods in the comet assay is the difficulty in obtaining enough blood cells from a single individual. In this study, we evaluated the genotoxic effects of the water-soluble fraction (WSF) of heavy oil on the brackish/freshwater amphipod Quadrivisio aff. lutzi, which is common in the coastal lagoons of southeastern Brazil, using hemocytes obtained from single amphipods (without pooling) after optimizing hemolymph extraction. The comet assay revealed significantly higher DNA damage levels (2- to 6-fold higher) in treated amphipods compared to untreated ones with a sublethal concentration of 17.6 % of the WSF within 72 h of treatment. Two independent experiments confirmed an "up and down" pattern of DNA damage, measured as the % of DNA contained in the tail of the comets. Elevations in DNA damage levels were observed at the 6 and 48 h time points, while very low levels of DNA damage were observed at the 24 and 72 h time points. Furthermore, the comet assay revealed gender variability in the levels of DNA damage after short-term exposure.

  12. Toxicity of oil dispersant, crude oil and dispersed crude oil to a marine amphipod and gastropod

    SciTech Connect

    Gulec, I.; Holdway, D.A.

    1995-12-31

    The importance of appropriate oil spill remedial action was emphasized during the recent Iron Barron oil spill off of the Tamar river in North Tasmania. One important potential oil spill response is dispersion, but little information exists on the toxicity of dispersants and dispersed oil to Australian marine species. This research was undertaken to assess the acute toxicity of Corexit 9527 (a widely used dispersant), water accommodated fractions of Bass Strait crude oil and dispersed Bass Strait crude oil, to the saltwater amphipod, Allorchestes compressa under semi-static conditions. Acute 96 h LC50`s were determined for each toxicant as well as for the reference toxicants sodium dodecyl sulfate (SDS) and zinc sulfate. Sublethal bioassays were undertaken for the same 3 toxicants utilizing the marines and snail Polinices conicus as the test species. No-observed-effect-concentrations (NOEC) and lowest-observed-effect-concentrations (LOEC) were determined using ANOVA while EC50`s and EC0`s were calculated using regression analysis. Mean acute 96 h LC50 (S.E.) values for A. compressa exposed to SDS and zinc sulfate were 3.6 mg/l (0.28) and 41.6 mg/l (9.01) respectively. EC50 (S.E.) concentrations for P. conicus exposed to SDS and zinc sulfate for 30 minutes were 44.7 mg/l and 246 mg/l respectively using burying behavior as an endpoint. These sublethal EC50`s were reduced to 20.7 mg/l for SDS and 23.5 mg/l for zinc sulfate following 24 hours of exposure.

  13. Toxicokinetics and critical body burden of fluoranthene in amphipod bioassays with Hyalella azteca and Diporeia sp.

    SciTech Connect

    Driscoll, S.K.; Landrum, P.

    1995-12-31

    Freshwater amphipods (Hyalella azteca and Diporeia sp.) were exposed to fluoranthene under yellow light in 10-day water-only and 30-day sediment bioassays. In water, the 10-d-LC50 for H. azteca (at 20 C) was 564 nmol/L (114 {micro}g/L). Survival of Diporeia (at 4 C) was higher, ranging from 87 to 97% at concentrations up to 1,285 nmol/L (260 {micro}g/L, the limit of water solubility). Although H. azteca was more sensitive than Diporeia to fluoranthene in water, it appeared to be less sensitive in sediment bioassays. Survival of H. azteca in sediment bioassays was generally greater than 90% at all doses, even after 30 d at the highest dose (136 nmol/gdw). A 10-d exposure of H. azteca to a sediment concentration (136 nmol/gdw) with an estimated interstitial water concentration (264 nmol/L), more than twice that of the water-only LC50 (114 nmol/L), resulted in only 5% mortality. In contrast, survival of Diporeia at the highest sediment dose (688 nmol/gdw) averaged 67%, 44%, and 16% after 10, 17 and 30-d exposures, respectively. Thus, although no substantial mortality was observed for Diporeia in water-only bioassays, sediment exposures resulted in significant dose dependent mortality. At the highest sediment doses, observed body burdens in Diporeia were in the range of 1--2 {micro}mol/gww, concentrations that would be expected to produce death by narcosis. In general, the body burden of H. azteca did not exceed 0.5 {micro}mol/gww in the sediment bioassay, which is consistent with the low mortality that was observed. Thus, measures of the actual dose in the organism best define the exposure. These results suggest that estimation of an interstitial water concentration may be insufficient for predicting sediment toxicity.

  14. A reformulated, reconstituted water for testing the freshwater amphipod, Hyalella azteca

    SciTech Connect

    Smith, M.E.; Herrin, L.E.; Thoeny, W.T.; Lazorchak, J.M.; Brewer-Swartz, S.

    1997-06-01

    Toxicity testing with the freshwater amphipod, Hyalella azteca, has routinely been conducted using nonstandard waters. Four waters were tested for acceptability for aqueous reference toxicant testing with H. azteca. These included three formulated (standardized) waters: moderately hard reconstituted water (MHRW), reformulated moderately hard reconstituted water (RMHRW), and 25% dilute mineral water (DMW). The water used for comparison was a nonstandard, in-house culture water mixture of well water and dechlorinated tap water, diluted with Super-Q{reg_sign} deionized water to a hardness of 100 mg/L, as CaCO{sub 3} (LL/SQ). Control survival was less than the 90% minimum control survival criteria in all tests with MHRW. Two of five tests with DMW also failed to pass the minimum control survival criteria. All five tests with the RMHRW passed the control survival criteria. The mean 50% lethal concentration (LC50) for the tests in RMHRW was 320 mg/L KCl, with a coefficient of variation of 8.5%. Concurrent tests with the in-house water yielded control survival greater than 90% and a mean LC50 of 216 mg/L KCl with a coefficient of variation of 13.4%. Tests in an interlaboratory study yielded similar results. Whole-sediment toxicity tests conducted using RMHRW as the overlying water routinely exceed the 80% minimum survival criteria in the control and reference sediments. The failure of MHRW and DMW to produce acceptable results, as well as the inability of other laboratories to produce LL/SQ, makes RMHRW the best candidate for a standard water for H. azteca testing.

  15. Using stable isotopes to assess carbon and nitrogen turnover in the Arctic sympagic amphipod Onisimus litoralis.

    PubMed

    Kaufman, Mette R; Gradinger, Rolf R; Bluhm, Bodil A; O'Brien, Diane M

    2008-11-01

    Food web studies based on stable C and N isotope ratios usually assume isotopic equilibrium between a consumer and its diet. In the Arctic, strong seasonality in food availability often leads to diet switching, resulting in a consumer's isotopic composition to be in flux between different food sources. Experimental work investigating the time course and dynamics of isotopic change in Arctic fauna has been lacking, although these data are crucial for accurate interpretation of food web relationships. We investigated seasonal (ice-covered spring vs. ice-free summer) and temperature (1 vs. 4 degrees C) effects on growth and stable C and N isotopic change in the common nearshore Arctic amphipod Onisimus litoralis following a diet switch and while fasting in the laboratory. In spring we found no significant temperature effect on N turnover [half-life (HL) estimates: HL-N = 20.4 at 4 degrees C, 22.4 days at 1 degrees C] and a nonsignificant trend for faster growth and C turnover at the higher temperature (HL-C = 13.9 at 4 degrees C, 18.7 days at 1 degrees C). A strong seasonal effect was found, with significantly slower growth and C and N turnover in the ice-free summer period (HL-N = 115.5 days, HL-C = 77.0 days). Contrary to previous studies, metabolic processes rather than growth accounted for most of the change in C and N isotopic composition (84-89 and 67-77%, respectively). This study provides the first isotopic change and metabolic turnover rates for an Arctic marine invertebrate and demonstrates the risk of generalizing turnover rates based on taxon, physiology, and environment. Our results highlight the importance of experimental work to determine turnover rates for species of interest.

  16. Linking sub-cellular biomarkers to embryo aberrations in the benthic amphipod Monoporeia affinis.

    PubMed

    Reutgard, Martin; Furuhagen, Sara

    2016-04-01

    To adequately assess and monitor environmental status in the aquatic environment a broad approach is needed that integrates physical variables, chemical analyses and biological effects at different levels of the biological organization. Embryo aberrations in the Baltic Sea key species Monoporeia affinis can be induced by both metals and organic substances as well as by hypoxia, increasing temperatures and malnutrition. This amphipod has therefore been used for more than three decades as a biological effect indicator in monitoring and assessment of chemical pollution and environmental stress. However, little is known about the sub-cellular mechanisms underlying embryo aberrations. An improved mechanistic understanding may open up the possibility of including sub-cellular alterations as sensitive warning signals of stress-induced embryo aberrations. In the present study, M. affinis was exposed in microcosms to 4 different sediments from the Baltic Sea. After 88-95 days of exposure, survival and fecundity were determined as well as the frequency and type of embryo aberrations. Moreover, oxygen radical absorption capacity (ORAC) was assayed as a proxy for antioxidant defense, thiobarbituric acid reactive substances (TBARS) level as a measure of lipid peroxidation and acetylcholinesterase (AChE) activity as an indicator of neurotoxicity. The results show that AChE and ORAC can be linked to the frequency of malformed embryos and arrested embryo development. The occurrence of dead broods was significantly associated with elevated TBARS levels. It can be concluded that these sub-cellular biomarkers are indicative of effects that could affect Darwinian fitness and that oxidative stress is a likely mechanism in the development of aberrant embryos in M. affinis. PMID:26836507

  17. Round-trip catadromous migration in a Japanese amphipod, Sternomoera rhyaca (Gammaridea: Eusiridae).

    PubMed

    Kuribayashi, Keiko; Katakura, Haruo; Kyono, Masaki; Dick, Matthew H; Mawatari, Shunsuke F

    2006-09-01

    We conducted a field study of the life cycle of the eusirid gammaridean amphipod Sternomoera rhyaca Kuribayashi, Mawatari, and Ishimaru, 1996 in a stream at Gokibiru, Hokkaido, Japan over the course of two non-consecutive years. This species is biennial; it spends most of its life in freshwater, but undertakes a short catadromous migration to the sea for reproduction. Reproduction occurs from March-June. Mature adults drift downstream to the sea singly and in precopulating pairs. Copulation and oviposition in the marsupium occur in mixed water at the stream mouth. Males die after copulation; ovigerous females return upstream by walking or swimming, where their eggs develop and hatch, after which the females also die. Juveniles remain in the stream, growing until they reach sexual maturity. Laboratory experiments showed that survivorship of all stages was lowest in seawater and highest in freshwater, though juveniles survived equally well in mixed water (50% seawater) and freshwater. Eggs developed to hatching only in freshwater; hatchlings in seawater and mixed water died within one and 21 days, respectively. Thus, S. rhyaca is well adapted to freshwater. Indeed, the only stages that required elevated salinity were copulation and subsequent oviposition, and we speculate that freshwater inhibits the female pre-reproductive molt. Because the life cycle of S. rhyaca has the most ontogenetically and temporally restricted saltwater phase known in any catadromous animal, its origin and maintenance are of evolutionary interest. We discuss two alternative hypotheses for the origin of the migratory life cycle, and discuss its maintenance in terms of fitness costs and benefits.

  18. Phylogeny as a Proxy for Ecology in Seagrass Amphipods: Which Traits Are Most Conserved?

    PubMed Central

    Best, Rebecca J.; Stachowicz, John J.

    2013-01-01

    Increasingly, studies of community assembly and ecosystem function combine trait data and phylogenetic relationships to gain novel insight into the ecological and evolutionary constraints on community dynamics. However, the key to interpreting these two types of information is an understanding of the extent to which traits are phylogenetically conserved. In this study, we develop the necessary framework for community phylogenetics approaches in a system of marine crustacean herbivores that play an important role in the ecosystem functioning of seagrass systems worldwide. For 16 species of amphipods and isopods, we (1) reconstructed phylogenetic relationships using COI, 16S, and 18S sequences and Bayesian analyses, (2) measured traits that are potentially important for assembling species between and within habitats, and (3) compared the degree to which each of these traits are evolutionarily conserved. Despite poor phylogenetic resolution for the order Amphipoda as a whole, we resolved almost all of the topology for the species in our system, and used a sampling of ultrametric trees from the posterior distribution to account for remaining uncertainty in topology and branch lengths. We found that traits varied widely in their degree of phylogenetic signal. Body mass, fecundity, and tube building showed very strong phylogenetic signal, and temperature tolerance and feeding traits showed much less. As such, the degree of signal was not predictable based on whether the trait is related to environmental filtering or to resource partitioning. Further, we found that even with strong phylogenetic signal in body size, (which may have large impacts on ecosystem function), the predictive relationship between phylogenetic diversity and ecosystem function is not straightforward. We show that patterns of phylogenetic diversity in communities of seagrass mesograzers could lead to a variety of interpretations and predictions, and that detailed study of trait similarities and

  19. Linking sub-cellular biomarkers to embryo aberrations in the benthic amphipod Monoporeia affinis.

    PubMed

    Reutgard, Martin; Furuhagen, Sara

    2016-04-01

    To adequately assess and monitor environmental status in the aquatic environment a broad approach is needed that integrates physical variables, chemical analyses and biological effects at different levels of the biological organization. Embryo aberrations in the Baltic Sea key species Monoporeia affinis can be induced by both metals and organic substances as well as by hypoxia, increasing temperatures and malnutrition. This amphipod has therefore been used for more than three decades as a biological effect indicator in monitoring and assessment of chemical pollution and environmental stress. However, little is known about the sub-cellular mechanisms underlying embryo aberrations. An improved mechanistic understanding may open up the possibility of including sub-cellular alterations as sensitive warning signals of stress-induced embryo aberrations. In the present study, M. affinis was exposed in microcosms to 4 different sediments from the Baltic Sea. After 88-95 days of exposure, survival and fecundity were determined as well as the frequency and type of embryo aberrations. Moreover, oxygen radical absorption capacity (ORAC) was assayed as a proxy for antioxidant defense, thiobarbituric acid reactive substances (TBARS) level as a measure of lipid peroxidation and acetylcholinesterase (AChE) activity as an indicator of neurotoxicity. The results show that AChE and ORAC can be linked to the frequency of malformed embryos and arrested embryo development. The occurrence of dead broods was significantly associated with elevated TBARS levels. It can be concluded that these sub-cellular biomarkers are indicative of effects that could affect Darwinian fitness and that oxidative stress is a likely mechanism in the development of aberrant embryos in M. affinis.

  20. Nutritional analysis of freshwater and marine amphipods from the Strait of Gibraltar and potential aquaculture applications

    NASA Astrophysics Data System (ADS)

    Baeza-Rojano, Elena; Hachero-Cruzado, Ismael; Guerra-García, José M.

    2014-01-01

    Four gammarid and four caprellid amphipod species from the Strait of Gibraltar were analyzed to study their nutritional contents: Caprella dilatata, Caprella equilibra, Caprella grandimana, Caprella penantis, Elasmopus rapax, Hyale perieri and Jassa sp. from marine water habitats and Echinogammarus sp. from freshwater habitats. Lipids, proteins, carbohydrates, ash and water contents were measured. Proteins and ash were the most abundant components in all the species, ranging between 37.9 and 44.6% and 29.3 and 39.7% dry weight, respectively. The lipid and carbohydrate contents showed lower levels (5.1-9.6% and 3.1-9.1% dry weight, respectively). No significant differences in general biochemical composition were found between gammarid and caprellid species. The most abundant fatty acids were the polyunsaturated ones (38.3%) with high levels of EPA (20:5(n-3)) with 8.5 to 17.7%, DHA (22:6(n-3)) with 0.9 to 13.6% and ARA (20:4(n-6)) with 1.7 to 5.8%. Caprellid species were characterized by a higher percentage of polyunsaturated fatty acids, while the freshwater gammarid species showed the lowest levels. According to lipid classes, caprellids had higher phospholipids levels and lower triacylglycerol levels, as well as a higher content of polar lipids than the gammarids, being more suitable for their use in aquaculture. Differences in the general biochemical composition between species can be related to habitat characteristics, diets and environmental conditions. Advantages and disadvantages of the use of these organisms in aquaculture are discussed.

  1. Round-trip catadromous migration in a Japanese amphipod, Sternomoera rhyaca (Gammaridea: Eusiridae).

    PubMed

    Kuribayashi, Keiko; Katakura, Haruo; Kyono, Masaki; Dick, Matthew H; Mawatari, Shunsuke F

    2006-09-01

    We conducted a field study of the life cycle of the eusirid gammaridean amphipod Sternomoera rhyaca Kuribayashi, Mawatari, and Ishimaru, 1996 in a stream at Gokibiru, Hokkaido, Japan over the course of two non-consecutive years. This species is biennial; it spends most of its life in freshwater, but undertakes a short catadromous migration to the sea for reproduction. Reproduction occurs from March-June. Mature adults drift downstream to the sea singly and in precopulating pairs. Copulation and oviposition in the marsupium occur in mixed water at the stream mouth. Males die after copulation; ovigerous females return upstream by walking or swimming, where their eggs develop and hatch, after which the females also die. Juveniles remain in the stream, growing until they reach sexual maturity. Laboratory experiments showed that survivorship of all stages was lowest in seawater and highest in freshwater, though juveniles survived equally well in mixed water (50% seawater) and freshwater. Eggs developed to hatching only in freshwater; hatchlings in seawater and mixed water died within one and 21 days, respectively. Thus, S. rhyaca is well adapted to freshwater. Indeed, the only stages that required elevated salinity were copulation and subsequent oviposition, and we speculate that freshwater inhibits the female pre-reproductive molt. Because the life cycle of S. rhyaca has the most ontogenetically and temporally restricted saltwater phase known in any catadromous animal, its origin and maintenance are of evolutionary interest. We discuss two alternative hypotheses for the origin of the migratory life cycle, and discuss its maintenance in terms of fitness costs and benefits. PMID:17043398

  2. Effects of current-use fungicides and their mixtures on the feeding and survival of the key shredder Gammarus fossarum.

    PubMed

    Zubrod, J P; Baudy, P; Schulz, R; Bundschuh, M

    2014-05-01

    Fungicides are frequently applied in agriculture and are subsequently detected in surface waters in total concentrations of up to several tens of micrograms per liter. These concentrations imply potential effects on aquatic communities and fundamental ecosystem functions such as leaf litter breakdown. In this context, the present study investigates sublethal and lethal effects of organic (azoxystrobin, carbendazim, cyprodinil, quinoxyfen, and tebuconazole) and inorganic (three copper (Cu)-based substances and sulfur) current-use fungicides and their mixtures on the key leaf-shredding invertebrate Gammarus fossarum. The feeding activity of fungicide-exposed gammarids was quantified as sublethal endpoint using a static (organic fungicides; 7 d test duration) or a semi-static (inorganic fungicides; 6 d test duration with a water exchange after 3 d) approach (n=30). EC50-values of organic fungicides were generally observed at concentrations resulting in less than 20% mortality, with the exception of carbendazim. With regard to feeding, quinoxyfen was the most toxic organic fungicide, followed by cyprodinil, carbendazim, azoxystrobin, and tebuconazole. Although all tested organic fungicides have dissimilar (intended) modes of action, a mixture experiment revealed a synergistic effect on gammarids' feeding at high concentrations when using "independent action" as the reference model (∼35% deviation between predicted and observed effect). This may be explained by the presence of a synergizing azole fungicide (i.e. tebuconazole) in this mixture. Furthermore, lethal concentrations of all Cu-based fungicides assessed in this study were comparable amongst one another. However, they differed markedly in their effective concentrations when using feeding activity as the endpoint, with Cu-sulfate being most toxic, followed by Cu-hydroxide and Cu-octanoate. In contrast, sulfur neither affected survival nor the feeding activity of gammarids (up to ∼5 mg/L) but reduced Cu

  3. Scavenging amphipods: sentinels for penetration of mercury and persistent organic chemicals into food webs of the deep Arctic Ocean.

    PubMed

    Bidleman, Terry F; Stern, Gary A; Tomy, Gregg T; Hargrave, Barry T; Jantunen, Liisa M; Macdonald, Robie W

    2013-06-01

    Archived specimens of the scavenging amphipod Eurythenes gryllus, collected from 2075 to 4250 m below the surface on five expeditions to the western and central Arctic Ocean between 1983 and 1998, were analyzed for total mercury (∑Hg), methyl mercury (MeHg), polychlorinated biphenyls (PCBs) and other industrial or byproduct organochlorines (chlorobenzenes, pentachloroanisole, octachlorostyrene), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs). Median ∑Hg concentrations ranged from 70 to 366 ng g(-1) wet weight (ww). MeHg concentrations (3.55 to 23.5 ng g(-1) ww) accounted for 1.7 to 20.1% (median 3.7%) of ∑Hg. ∑Hg and MeHg were positively and significantly correlated with ww (∑Hg r(2) = 0.18, p = 0.0004, n = 63; MeHg r(2) = 0.42, p = 0.0004, n = 25), but not significantly with δ(13)C nor δ(15)N. Median concentrations of total persistent organic pollutants (POPs) ranged from 9750 to 156,000 ng g(-1) lipid weight, with order of abundance: ∑TOX (chlorobornanes quantified as technical toxaphene) > ∑PCBs > ∑DDTs > ∑chlordanes > ∑mirex compounds > ∑BDEs ∼ ∑chlorobenzenes ∼ octachlorostyrene > α-hexachlorocyclohexane ∼ hexachlorobenzene ∼ pentachloroanisole. Enantioselective accumulation was found for the chiral OCPs o,p'-DDT, cis- and trans-chlordane, nonachlor MC6 and oxychlordane. Lipid-normalized POPs concentrations were elevated in amphipods with lipid percentages ≤10%, suggesting that utilization of lipids resulted in concentration of POPs in the remaining lipid pool. Multidimensional Scaling (MDS) analysis using log-transformed physiological variables and lipid-normalized organochlorine concentrations distinguished amphipods from the central vs western arctic stations. This distinction was also seen for PCB homologues, whereas profiles of other compound classes were more related to specific stations rather than central-west differences.

  4. Size-related bioaccumulation and between-year variation of organochlorines in ice-associated amphipods from the Arctic Ocean.

    PubMed

    Borgå, Katrine; Gulliksen, Bjørn; Gabrielsen, Geir Wing; Skaare, Janneche Utne

    2002-03-01

    Organochlorines are found even in organisms living in remote areas such as the Arctic marginal ice zone. Organochlorine concentrations in ice-associated (sympagic) amphipods are related to their diet. Therefore, the size-dependent diet shift of Gamunarus wilkitzkii may influence its organochlorine content. In this preliminary study, the organochlorine concentrations in two size classes (small < or = 29 mm and large >29 mm) of G. wilkitzkii were analysed. The concentrations of more lipophilic compounds [e.g. polychlorinated biphenyls (PCBs)] were lower in the small than the large size class, whereas concentrations of less lipophilic compounds [e.g. hexachlorocyclohexanes (HCHs)] did not differ by size class. Since contamination transport by the atmosphere, ocean currents and sea ice may vary, the organochlorine burden in sympagic organisms may also vary. There are no data available on temporal variation of organochlorine burden in Arctic sympagic fauna. Therefore, we compared organochlorine concentrations in sympagic amphipods (G. wilkitzkii, Apherusa glacialis and Onisimus spp.) between 1998 and 1999. Organochlorine concentrations in all amphipods were low in both years, with sum organochlorines from 50.7 to 621.9 ngg(-1) lipid weight. The concentrations of hexachlorobenzene (HCB), chlordanes, DDTs and PCBs were higher in 1999 than 1998, whereas the HCH concentrations were lower in 1999 than 1998. The organochlorine concentrations differed between the taxa in both years in a similar increasing manner from A. glacialis to both G. wilkitzkii and Onisimus spp In studies of bioaccumulation relative to body size and temporal variation, a thorough interpretation requires samples from several size classes and years. Nevertheless, the present data provide new knowledge on contaminants in Arctic invertebrates where data are scarce.

  5. Ameliorating effect of chloride on nitrite toxicity to freshwater invertebrates with different physiology: a comparative study between amphipods and planarians.

    PubMed

    Alonso, A; Camargo, J A

    2008-02-01

    High nitrite concentrations in freshwater ecosystems may cause toxicity to aquatic animals. These living organisms can take nitrite up from water through their chloride cells, subsequently suffering oxidation of their respiratory pigments (hemoglobin, hemocyanin). Because NO(2)(-) and Cl(-) ions compete for the same active transport site, elevated chloride concentrations in the aquatic environment have the potential of reducing nitrite toxicity. Although this ameliorating effect is well documented in fish, it has been largely ignored in wild freshwater invertebrates. The aim of this study was to compare the ameliorating effect of chloride on nitrite toxicity to two species of freshwater invertebrates differing in physiology: Eulimnogammarus toletanus (amphipods) and Polycelis felina (planarians). The former species presents gills (with chloride cells) and respiratory pigments, whereas in the latter species these are absent. Test animals were exposed in triplicate for 168 h to a single nitrite concentration (5 ppm NO(2)-N for E. toletanus and 100 ppm NO(2)-N for P. felina) at four different environmental chloride concentrations (27.8, 58.3, 85.3, and 108.0 ppm Cl(-)). The number of dead animals and the number of affected individuals (i.e., number of dead plus inactive invertebrates) were monitored every day. LT(50) (lethal time) and ET(50) (effective time) were estimated for each species and each chloride concentration. LT(50) and ET(50) values increased with increases in the environmental chloride concentration, mainly in amphipods. Results clearly show that the ameliorating effect of chloride on nitrite toxicity was more significant in amphipods than in planarians, likely because of the absence of gills (with chloride cells) and respiratory pigments in P. felina. Additionally, this comparative study indicates that the ecological risk assessment of nitrite in freshwater ecosystems should take into account not only the most sensitive and key species in the

  6. Effects of Sublethal Cadmium Exposure on Antipredator Behavioural and Antitoxic Responses in the Invasive Amphipod Dikerogammarus villosus

    PubMed Central

    Sornom, Pascal; Gismondi, Eric; Vellinger, Céline; Devin, Simon; Férard, Jean-François; Beisel, Jean-Nicolas

    2012-01-01

    Amphipods are recognised as an important component of freshwater ecosystems and are frequently used as an ecotoxicological test species. Despite this double interest, there is still a lack of information concerning toxic impacts on ecologically relevant behaviours. The present study investigated the influence of cadmium (Cd), a non-essential heavy metal, on both antipredator behaviours and antitoxic responses in the invasive amphipod Dikerogammarus villosus under laboratory conditions. Amphipod behaviour (i.e. refuge use, aggregation with conspecifics, exploration and mobility) was recorded following a 4-min test-exposure to 500 µg Cd/L with or without a 24-h Cd pre-exposure and in the presence or absence of a high perceived risk of predation (i.e. water scented by fish predators and injured conspecifics). Following behavioural tests, malondialdehyde (MDA) levels, a biomarker for toxic effect, and energy reserves (i.e. lipid and glycogen contents) were assessed. Cd exposures induced (1) cell damage reflected by high MDA levels, (2) erratic behaviour quantified by decreasing refuge use and exploration, and increasing mobility, and (3) a depletion in energy reserves. No significant differences were observed between 4-min test-exposed and 24-h pre-exposed individuals. Gammarids exposed to Cd had a disturbed perception of the alarm stimuli, reflected by increased time spent outside of refuges and higher mobility compared to gammarids exposed to unpolluted water. Our results suggest that Cd exposure rapidly disrupts the normal behavioural responses of gammarids to alarm substances and alters predator-avoidance strategies, which could have potential impacts on aquatic communities. PMID:22879985

  7. Corophiine amphipods of the genera Chelicorophium and Paracorophium from the lower Gulf of Thailand (Crustacea, Amphipoda, Corophiidae, Corophiinae)

    PubMed Central

    Wongkamhaeng, Koraon; Nabhitabhata, Jaruwat; Towatana, Prawit

    2015-01-01

    Abstract Two species of corophiine amphipods from Songkhla Lake, in the lower Gulf of Thailand, are described and illustrated. Chelicorophium madrasensis (Nayar, 1950), found in the mangrove forest, has not previously been observed in Thai waters. Paracorophium angsupanichae sp. n. is characterized by its chelate male gnathopod 2, obtuse palm with subrectangular distomedial elevation, and urosomites 1-3 free. This is the first record of the genus Chelicorophium and Paracorophium in Thai waters. All specimens are deposited in the Princess Maha Chakri Sirindhorn Natural History Museum, Prince of Songkla University, Thailand and the Museum für Naturkunde, Berlin. PMID:26052237

  8. Leucothoe eltoni sp. n., a new species of commensal leucothoid amphipod from coral reefs in Raja Ampat, Indonesia (Crustacea, Amphipoda)

    PubMed Central

    Thomas, James Darwin

    2015-01-01

    Abstract A new species of leucothoid amphipod, Leucothoe eltoni sp. n., is described from coral reefs in Raja Ampat, Indonesia where it inhabits the branchial chambers of solitary tunicates. With an inflated first gnathopod superficially resembling the genus Paraleucothoe, this new species has a two-articulate maxilla 1 palp characteristic of the genus Leucothoe. While described from coral reef environments in tropical Indonesia and the Philippines, it is an established invasive species in the Hawaiian Islands. The most likely mode of introduction was a US Navy dry dock transported to Pearl Harbor in 1992 from Subic Bay, Philippines. PMID:26448700

  9. Leucothoe eltoni sp. n., a new species of commensal leucothoid amphipod from coral reefs in Raja Ampat, Indonesia (Crustacea, Amphipoda).

    PubMed

    Thomas, James Darwin

    2015-01-01

    A new species of leucothoid amphipod, Leucothoe eltoni sp. n., is described from coral reefs in Raja Ampat, Indonesia where it inhabits the branchial chambers of solitary tunicates. With an inflated first gnathopod superficially resembling the genus Paraleucothoe, this new species has a two-articulate maxilla 1 palp characteristic of the genus Leucothoe. While described from coral reef environments in tropical Indonesia and the Philippines, it is an established invasive species in the Hawaiian Islands. The most likely mode of introduction was a US Navy dry dock transported to Pearl Harbor in 1992 from Subic Bay, Philippines.

  10. Investigation of the soluble metals in tissue as biological response pattern to environmental pollutants (Gammarus fossarum example).

    PubMed

    Filipović Marijić, Vlatka; Dragun, Zrinka; Sertić Perić, Mirela; Matoničkin Kepčija, Renata; Gulin, Vesna; Velki, Mirna; Ečimović, Sandra; Hackenberger, Branimir K; Erk, Marijana

    2016-07-01

    In the present study, Gammarus fossarum was used to investigate the bioaccumulation and toxic effects of aquatic pollutants in the real environmental conditions. The novelty of the study is the evaluation of soluble tissue metal concentrations in gammarids as indicators in early assessment of metal exposure. In the Sutla River, industrially/rurally/agriculturally influenced catchment in North-Western Croatia, physico-chemical water properties pointed to disturbed ecological status, which was reflected on population scale as more than 50 times lower gammarid density compared to the reference location, Črnomerec Stream. Significantly higher levels of soluble toxic metals (Al, As, Cd, Pb, Sb, Sn, Sr) were observed in gammarids from the Sutla River compared to the reference site and reflected the data on higher total dissolved metal levels in the river water at that site. The soluble metal estimates were supplemented with the common multibiomarker approach, which showed significant biological responses for decreased acetylcholinesterase activity and increased total soluble protein concentrations, confirming stressed environmental conditions for biota in the Sutla River. Biomarker of metal exposure, metallothionein, was not induced and therefore, toxic effect of metals was not confirmed on molecular level. Comparable between-site pattern of soluble toxic metals in gammarids and total dissolved metal levels in water suggests that prior to biomarker response and observed toxic impact, soluble metals in tissue might be used as early warning signs of metal impact in the aquatic environment and improve the assessment of water quality.

  11. Ecophysiological responses to temperature of the "killer shrimp" Dikerogammarus villosus: is the invader really stronger than the native Gammarus pulex?

    PubMed

    Maazouzi, C; Piscart, C; Legier, F; Hervant, F

    2011-07-01

    With global climate changes, biological invasions are considered to be one of the main causes of the decline of freshwater biodiversity. In this context, predicted increases in global temperature may alter the geographical distributions of native and invasive species. The purpose of our study was to examine the metabolic, behavioral and physiological responses to short-term temperature acclimation of two widely distributed species (the most successful European invader, Dikerogammarus villosus, and its main victim, Gammarus pulex), in order to estimate the potential effect of global warming on its invasion of freshwater ecosystems. Our results show that D. villosus is more vulnerable to high temperatures than G. pulex. The native species seems to be best adapted to intermediate temperatures (10-20°C) with a possibility of adjustment to "extreme" temperatures (5-27°C), whereas the "killer shrimp" D. villosus seems best adapted to lower temperatures (5-10°C) with a limited possibility of adjustment above 20°C. In the light of our results, global warming is likely to be less favorable to the invasive species. However, D. villosus showed reduced metabolic and activity rates, associated with higher glycogen content. This adaptive strategy was interpreted as having functional advantages, allowing D. villosus to successfully invade harsh and/or unpredictable biotopes. In addition, our results show that glycogen stores may be used as a powerful indicator of the optimal thermal window for aquatic ectotherms.

  12. An approach to the assessment of risk from chronic radiation to populations of European lobster, Homarus gammarus (L.).

    PubMed

    Vives i Batlle, Jordi; Wilson, R C; Watts, S J; McDonald, P; Jones, S R; Vives-Lynch, S M; Craze, A

    2010-03-01

    The basic principles underlying a four-discrete age group, logistic, growth model for the European lobster Homarus gammarus are presented and discussed at proof-of-concept level. The model considers reproduction, removal by predation, natural death, fishing, radiation and migration. Non-stochastic effects of chronic low linear energy transfer (LET) radiation are modelled with emphasis on (99)Tc, using three endpoints: repairable radiation damage, impairment of reproductive ability and, at higher dose rates, mortality. An allometric approach for the calculation of LD(50/30) as a function of the mass of each life stage is used in model calibration. The model predicts that at a dose rate of 1 Gy day(-1), lobster population reproduction and survival become severely compromised, leading eventually to population extinction. At 0.01 Gy day(-1), the survival rate of an isolated population is reduced by 10%, mainly through loss of fecundity, comparable to natural migration losses. Fishing is the main ecological stress and only dose rates in the range 0.03-0.1 Gy day(-1) can achieve discernible effects above it. On the balance of radiation and other ecological stresses, a benchmark value of 0.01 Gy day(-1) is proposed for the protection of lobster populations. This value appears consistent with available information on radiation effects in wildlife. PMID:19855992

  13. Comparative toxicity of dissolved metals to early larval stages of Palaemon serratus, Maja squinado, and Homarus gammarus (Crustacea:Decapoda).

    PubMed

    Mariño-Balsa, J C; Poza, E; Vázquez, E; Beiras, R

    2000-10-01

    The acute lethal toxicities of mercury, copper, and cadmium to the first larval stage of the prawn (Palaemon serratus), spider crab (Maja squinado), and lobster (Homarus gammarus) were tested. Chromium was also tested with the prawn. Mortality was recorded after 48 h (for lobster) or 72 h (for other species) incubation at 18 degrees C, and the median lethal concentrations (LC(50) +/- 95% confidence intervals) per individual and per mass unit were calculated. The LC(50) values were, 74 microg Hg/L, 3,304 microg Cu/L, 1,686 microg Cd/L, 12,486 microg Cr/L for prawn; 72 microg Hg/L, 50 microg Cu/L, 158 microg Cd/L for spider crab; and 48 microg Hg/L, 46 microg Cu/L, 34 microg Cd/L for lobster. Therefore, larvae of spider crab and lobster were markedly more sensitive than prawn to heavy metals and thus more suitable to use in seawater quality bioassays. Of these two species, spider crab is recommended due to its abundance, easier maintenance, and higher fecundity. The mercury LC(50) values for different larval stages of P. serratus (zoea I, II, V, and VI) were obtained, and no ontogenetic change in sensitivity to the metal could be detected. PMID:10948285

  14. Cold-adapted digestive aspartic protease of the clawed lobsters Homarus americanus and Homarus gammarus: biochemical characterization.

    PubMed

    Rojo, Liliana; García-Carreño, Fernando; de Los Angeles Navarrete del Toro, Maria

    2013-02-01

    Aspartic proteinases in the gastric fluid of clawed lobsters Homarus americanus and Homarus gammarus were isolated to homogeneity by single-step pepstatin-A affinity chromatography; such enzymes have been previously identified as cathepsin D-like enzymes based on their deduced amino acid sequence. Here, we describe their biochemical characteristics; the properties of the lobster enzymes were compared with those of its homolog, bovine cathepsin D, and found to be unique in a number of ways. The lobster enzymes demonstrated hydrolytic activity against synthetic and natural substrates at a wider range of pH; they were more temperature-sensitive, showed no changes in the K(M) value at 4°C, 10°C, and 25°C, and had 20-fold higher k(cat)/K(M) values than bovine enzyme. The bovine enzyme was temperature-dependent. We propose that both properties arose from an increase in molecular flexibility required to compensate for the reduction of reaction rates at low habitat temperatures. This is supported by the fast denaturation rates induced by temperature. PMID:22648335

  15. Morphology and pathology of the ectoparasitic copepod, Nicothoë astaci ('lobster louse') in the European lobster, Homarus gammarus.

    PubMed

    Wootton, Emma C; Pope, Edward C; Vogan, Claire L; Roberts, Emily C; Davies, Charlotte E; Rowley, Andrew F

    2011-09-01

    Ectoparasitic copepods have been reported in a wide range of aquatic animals, including crustacean shellfish. However, with the exception of the salmon louse, Lepeophtheirus salmonis, our knowledge of such parasites in commercial species is rudimentary. The current study examines the morphology and pathology of the parasitic copepod, Nicothoë astaci (the 'lobster louse') in its host, the European lobster, Homarus gammarus. Lobsters were sampled from waters surrounding Lundy Island (Bristol Channel, UK) and all individuals collected were found to harbour female adult N. astaci in their gills, with a mean of 47·3 parasites/lobster. The majority of N. astaci were found in the basal region of pleurobranch gills. The parasite was found to attach to gill filaments via its oral sucker, maxillae and maxillipeds, and to feed on host haemolymph (blood) through a funnel-like feeding channel. It caused varying degrees of damage to the host gill, including occlusion of gill filaments and disruption to the vascular system in the central axis. Although there was evidence of extensive host response (haemocytic infiltration) to the parasite, it was displaced from the parasite attachment site and thus was observed in the central gill axis below. The region of gill filament immediately underlying the parasite feeding channel was devoid of such activity suggesting that the parasite interferes with the cellular defence and haemostatic mechanisms of the lobster in order to maintain invasion of the host. PMID:21756425

  16. Transfer across the human gut of environmental technetium in lobsters (Homarus gammarus L.) from the Irish Sea.

    PubMed

    Hunt, G J; Young, A K; Bonfield, R A

    2001-03-01

    Few data are available on the uptake by the human gut of the element technetium. Of current radiological interest in connection with discharges of technetium-99 in liquid discharges from BNFL, Sellafield, is uptake from European lobsters (Homarus gammarus), whose edible parts are known to concentrate technetium. In this study, a group of eight adult volunteers (six males and two females) ate samples of edible flesh from lobsters caught off the west Cumbrian coast and provided 24 h samples of urine and faeces for analysis. Detection of uptake from the gut by difference between intake and faecal measurements proved insensitive, suggesting a low value of the gut transfer factor (f1 value) of up to 0.1 with a maximum (two standard deviations) level of about 0.3. In urine, technetium was detectable at a relatively low level compared with the intakes, consistent with a low absorption across the gut. Values for f1 were derived with the aid of literature data for excretion following intravenous administration of technetium-95 m as pertechnetate, and gave averaged data for f1 in the range 0.046 to 0.23. These results are in broad conformity with those derived from the faecal measurements, and suggest a lower value than the 0.5 used by ICRP. PMID:11281526

  17. Histological intersex (ovotestis) in the European lobster Homarus gammarus and a commentary on its potential mechanistic basis.

    PubMed

    Stentiford, G D

    2012-08-27

    This paper provides the first report of the intersex (ovotestis) condition in the European lobster Homarus gammarus. A single specimen (10% of males sampled) presenting the condition was discovered as part of routine sampling, from the Weymouth Bay region of the English Channel, UK. The lobster presented externally as a male, but upon histological examination was seen to contain an ovotestis, containing elements of both male and female gonadal tissue. Previtellogenic oocytes were present in several otherwise normal seminiferous tubules throughout the testis. The seminiferous tubules were also engaged in the production of apparently normal sperm lineages, and mature spermatozoa were present within the tubule lumens. In some cases, oocytes were in direct contact with mature spermatozoa within the same seminiferous tubules. The significance of this finding is placed into context with a previous observation of elevated intersexuality in the congeneric species H. americanus collected from specific sites in Canadian waters. The potential mechanism for development of intersex in lobsters, which is probably related to a disrupted signalling to the germinal component of the testis from the decapod androgenic gland, may be an effect of exposure to endocrine disrupting chemicals in the marine environment. PMID:23186705

  18. Ultrastructural studies and Na+,K+-ATPase immunolocalization in the antennal urinary glands of the lobster Homarus gammarus (Crustacea, Decapoda).

    PubMed

    Khodabandeh, Saber; Charmantier, Guy; Charmantier-Daures, Mireille

    2005-10-01

    Unlike in crustacean freshwater species, the structure and ultrastructure of the excretory antennal gland is poorly documented in marine species. The general organization and ultrastructure of the cells and the localization of Na(+),K(+)-ATPase were examined in the antennal gland of the adult lobster Homarus gammarus. Each gland is composed of a centrally located coelomosac surrounded ventrally by a labyrinth divided into two parts (I and II) and dorsally by a voluminous bladder. There is no differentiated nephridal tubule between them. The labyrinth and bladder cells have in common a number of ultrastructural cytological features, including basal membrane infoldings associated with mitochondria, apical microvilli, and cytoplasmic extrusions, and a cytoplasm packed with numerous vacuoles, vesicles, lysosome-like bodies, and swollen mitochondria. Each type of cell also presents distinctive characters. Na(+),K(+)-ATPase was detected through immunofluorescence in the basal part of the cells of the labyrinth and in the bladder cells with an increasing immunostaining from labyrinth I to the bladder. No immunoreactivity was detected in the coelomosac. The cells of the labyrinth and of the bladder present morphological and enzymatic features of ionocytes. The antennal glands of the lobster thus possess active ion exchanges capabilities. PMID:15879578

  19. Ultrastructural studies and Na+,K+-ATPase immunolocalization in the antennal urinary glands of the lobster Homarus gammarus (Crustacea, Decapoda).

    PubMed

    Khodabandeh, Saber; Charmantier, Guy; Charmantier-Daures, Mireille

    2005-10-01

    Unlike in crustacean freshwater species, the structure and ultrastructure of the excretory antennal gland is poorly documented in marine species. The general organization and ultrastructure of the cells and the localization of Na(+),K(+)-ATPase were examined in the antennal gland of the adult lobster Homarus gammarus. Each gland is composed of a centrally located coelomosac surrounded ventrally by a labyrinth divided into two parts (I and II) and dorsally by a voluminous bladder. There is no differentiated nephridal tubule between them. The labyrinth and bladder cells have in common a number of ultrastructural cytological features, including basal membrane infoldings associated with mitochondria, apical microvilli, and cytoplasmic extrusions, and a cytoplasm packed with numerous vacuoles, vesicles, lysosome-like bodies, and swollen mitochondria. Each type of cell also presents distinctive characters. Na(+),K(+)-ATPase was detected through immunofluorescence in the basal part of the cells of the labyrinth and in the bladder cells with an increasing immunostaining from labyrinth I to the bladder. No immunoreactivity was detected in the coelomosac. The cells of the labyrinth and of the bladder present morphological and enzymatic features of ionocytes. The antennal glands of the lobster thus possess active ion exchanges capabilities.

  20. An Enriched Environment Promotes Shelter-Seeking Behaviour and Survival of Hatchery-Produced Juvenile European Lobster (Homarus gammarus).

    PubMed

    Aspaas, Stian; Grefsrud, Ellen Sofie; Fernö, Anders; Jensen, Knut Helge; Trengereid, Henrik; Agnalt, Ann-Lisbeth

    2016-01-01

    The high loss of newly released hatchery-reared European lobster (Homarus gammarus) juveniles for stock enhancement is believed to be the result of maladaptive anti-predator behaviour connected to deprived stimuli in the hatchery environment. Our objective was to learn if an enriched hatchery environment enhances shelter-seeking behaviour and survival. In the "naïve" treatment, the juveniles were raised in single compartments without substrate and shelter whereas juveniles in the "exposed" treatment experienced substrate, shelter and interactions with conspecifics. Three experiments with increasing complexity were conducted. Few differences in shelter-seeking behaviour were found between treatments when one naïve or one exposed juvenile were observed alone. When observing interactions between one naïve and one exposed juvenile competing for shelter, naïve juveniles more often initiated the first aggressive encounter. The third experiment was set up to simulate a release for stock enhancement. Naïve and exposed juveniles were introduced to a semi-natural environment including substrate, a limited number of shelters and interactions with conspecifics. Shelter occupancy was recorded three times during a period of 35 days. Exposed juveniles occupied more shelters, grew larger and had higher survival compared with naïve juveniles. Our results demonstrate that experience of environmental complexity and social interactions increase shelter-seeking ability and survival in hatchery reared lobster juveniles.

  1. An Enriched Environment Promotes Shelter-Seeking Behaviour and Survival of Hatchery-Produced Juvenile European Lobster (Homarus gammarus)

    PubMed Central

    Aspaas, Stian; Grefsrud, Ellen Sofie; Fernö, Anders; Jensen, Knut Helge; Trengereid, Henrik; Agnalt, Ann-Lisbeth

    2016-01-01

    The high loss of newly released hatchery-reared European lobster (Homarus gammarus) juveniles for stock enhancement is believed to be the result of maladaptive anti-predator behaviour connected to deprived stimuli in the hatchery environment. Our objective was to learn if an enriched hatchery environment enhances shelter-seeking behaviour and survival. In the “naïve” treatment, the juveniles were raised in single compartments without substrate and shelter whereas juveniles in the “exposed” treatment experienced substrate, shelter and interactions with conspecifics. Three experiments with increasing complexity were conducted. Few differences in shelter-seeking behaviour were found between treatments when one naïve or one exposed juvenile were observed alone. When observing interactions between one naïve and one exposed juvenile competing for shelter, naïve juveniles more often initiated the first aggressive encounter. The third experiment was set up to simulate a release for stock enhancement. Naïve and exposed juveniles were introduced to a semi-natural environment including substrate, a limited number of shelters and interactions with conspecifics. Shelter occupancy was recorded three times during a period of 35 days. Exposed juveniles occupied more shelters, grew larger and had higher survival compared with naïve juveniles. Our results demonstrate that experience of environmental complexity and social interactions increase shelter-seeking ability and survival in hatchery reared lobster juveniles. PMID:27560932

  2. Morphology and pathology of the ectoparasitic copepod, Nicothoë astaci ('lobster louse') in the European lobster, Homarus gammarus.

    PubMed

    Wootton, Emma C; Pope, Edward C; Vogan, Claire L; Roberts, Emily C; Davies, Charlotte E; Rowley, Andrew F

    2011-09-01

    Ectoparasitic copepods have been reported in a wide range of aquatic animals, including crustacean shellfish. However, with the exception of the salmon louse, Lepeophtheirus salmonis, our knowledge of such parasites in commercial species is rudimentary. The current study examines the morphology and pathology of the parasitic copepod, Nicothoë astaci (the 'lobster louse') in its host, the European lobster, Homarus gammarus. Lobsters were sampled from waters surrounding Lundy Island (Bristol Channel, UK) and all individuals collected were found to harbour female adult N. astaci in their gills, with a mean of 47·3 parasites/lobster. The majority of N. astaci were found in the basal region of pleurobranch gills. The parasite was found to attach to gill filaments via its oral sucker, maxillae and maxillipeds, and to feed on host haemolymph (blood) through a funnel-like feeding channel. It caused varying degrees of damage to the host gill, including occlusion of gill filaments and disruption to the vascular system in the central axis. Although there was evidence of extensive host response (haemocytic infiltration) to the parasite, it was displaced from the parasite attachment site and thus was observed in the central gill axis below. The region of gill filament immediately underlying the parasite feeding channel was devoid of such activity suggesting that the parasite interferes with the cellular defence and haemostatic mechanisms of the lobster in order to maintain invasion of the host.

  3. Consequences of Lower Food Intake on the Digestive Enzymes Activities, the Energy Reserves and the Reproductive Outcome in Gammarus fossarum

    PubMed Central

    Charron, Laetitia; Geffard, Olivier; Chaumot, Arnaud; Coulaud, Romain; Jaffal, Ali; Gaillet, Véronique; Dedourge-Geffard, Odile; Geffard, Alain

    2015-01-01

    Digestive enzyme activity is often used as a sensitive response to environmental pollution. However, only little is known about the negative effects of stress on digestive capacities and their consequences on energy reserves and reproduction, although these parameters are important for the maintenance of populations. To highlight if changes in biochemical responses (digestive enzymes and reserves) led to impairments at an individual level (fertility), Gammarus fossarum were submitted to a lower food intake throughout a complete female reproductive cycle (i.e. from ovogenesis to offspring production). For both males and females, amylase activity was inhibited by the diet stress, whereas trypsin activity was not influenced. These results underline similar sensitivity of males and females concerning their digestive capacity. Energy reserves decreased with food starvation in females, and remained stable in males. The number of embryos per female decreased with food starvation. Lower digestive activity in males and females therefore appears as an early response. These results underline the ecological relevance of digestive markers, as they make it possible to anticipate upcoming consequences on reproduction in females, a key biological variable for population dynamics. PMID:25880985

  4. Investigation of the soluble metals in tissue as biological response pattern to environmental pollutants (Gammarus fossarum example).

    PubMed

    Filipović Marijić, Vlatka; Dragun, Zrinka; Sertić Perić, Mirela; Matoničkin Kepčija, Renata; Gulin, Vesna; Velki, Mirna; Ečimović, Sandra; Hackenberger, Branimir K; Erk, Marijana

    2016-07-01

    In the present study, Gammarus fossarum was used to investigate the bioaccumulation and toxic effects of aquatic pollutants in the real environmental conditions. The novelty of the study is the evaluation of soluble tissue metal concentrations in gammarids as indicators in early assessment of metal exposure. In the Sutla River, industrially/rurally/agriculturally influenced catchment in North-Western Croatia, physico-chemical water properties pointed to disturbed ecological status, which was reflected on population scale as more than 50 times lower gammarid density compared to the reference location, Črnomerec Stream. Significantly higher levels of soluble toxic metals (Al, As, Cd, Pb, Sb, Sn, Sr) were observed in gammarids from the Sutla River compared to the reference site and reflected the data on higher total dissolved metal levels in the river water at that site. The soluble metal estimates were supplemented with the common multibiomarker approach, which showed significant biological responses for decreased acetylcholinesterase activity and increased total soluble protein concentrations, confirming stressed environmental conditions for biota in the Sutla River. Biomarker of metal exposure, metallothionein, was not induced and therefore, toxic effect of metals was not confirmed on molecular level. Comparable between-site pattern of soluble toxic metals in gammarids and total dissolved metal levels in water suggests that prior to biomarker response and observed toxic impact, soluble metals in tissue might be used as early warning signs of metal impact in the aquatic environment and improve the assessment of water quality. PMID:27060638

  5. An Enriched Environment Promotes Shelter-Seeking Behaviour and Survival of Hatchery-Produced Juvenile European Lobster (Homarus gammarus).

    PubMed

    Aspaas, Stian; Grefsrud, Ellen Sofie; Fernö, Anders; Jensen, Knut Helge; Trengereid, Henrik; Agnalt, Ann-Lisbeth

    2016-01-01

    The high loss of newly released hatchery-reared European lobster (Homarus gammarus) juveniles for stock enhancement is believed to be the result of maladaptive anti-predator behaviour connected to deprived stimuli in the hatchery environment. Our objective was to learn if an enriched hatchery environment enhances shelter-seeking behaviour and survival. In the "naïve" treatment, the juveniles were raised in single compartments without substrate and shelter whereas juveniles in the "exposed" treatment experienced substrate, shelter and interactions with conspecifics. Three experiments with increasing complexity were conducted. Few differences in shelter-seeking behaviour were found between treatments when one naïve or one exposed juvenile were observed alone. When observing interactions between one naïve and one exposed juvenile competing for shelter, naïve juveniles more often initiated the first aggressive encounter. The third experiment was set up to simulate a release for stock enhancement. Naïve and exposed juveniles were introduced to a semi-natural environment including substrate, a limited number of shelters and interactions with conspecifics. Shelter occupancy was recorded three times during a period of 35 days. Exposed juveniles occupied more shelters, grew larger and had higher survival compared with naïve juveniles. Our results demonstrate that experience of environmental complexity and social interactions increase shelter-seeking ability and survival in hatchery reared lobster juveniles. PMID:27560932

  6. Amphipod-supported food web: Themisto gaudichaudii, a key food resource for fishes in the southern Patagonian Shelf

    NASA Astrophysics Data System (ADS)

    Padovani, Luciano N.; Viñas, María Delia; Sánchez, Felisa; Mianzan, Hermes

    2012-01-01

    The trophic role of the hyperiid amphipod Themisto gaudichaudii in the southern Patagonian shelf food web was assessed from the analysis of stomach contents of the local fish assemblage. A total of 461 trawl samples were collected during seven seasonal cruises. A total of 17 out of 38 fish species were found to ingest T. gaudichaudii. This amphipod was a main prey item in five of these species, showing high values of alimentary index: Seriolella porosa (99.9%), Macruronus magellanicus (68.8%), Micromesistius australis (59.1%), Patagonotothen ramsayi (48.6%), and Merluccius hubbsi (10.9%). The contribution of T. gaudichaudii, in weight, to their summer diet was 60%, on average. This contribution was minimal in winter and maximal in summer. Fisheries studies have indicated that these five species, mainly M. magellanicus, account for almost 85% of the fish biomass in the area. Although the remaining 15% did not feed heavily on T. gaudichaudii, they are known to prey on the main hyperiid predators. Our study shows that T. gaudichaudii contributes greatly, both directly and indirectly, to supporting the fish community. We thus proposed that T. gaudichaudii plays a key role as a "wasp-waist" species in the sub-Antarctic region, similar to that of krill in Antarctic waters, channeling the energy flow and enabling a short and efficient food chain.

  7. Trophic interactions of macro-zooplankton (krill and amphipods) in the Marginal Ice Zone of the Barents Sea

    NASA Astrophysics Data System (ADS)

    Dalpadado, Padmini; Yamaguchi, Atsushi; Ellertsen, Bjørnar; Johannessen, Signe

    2008-10-01

    The diets of krill and amphipods were examined using light microscopy on field-collected specimens from 2004 to 2005 from the Marginal Ice Zone of the northwestern Barents Sea, north and east of Spitsbergen. Stomach content analyses indicate dominant krill species to have a filter-feeding mode, whereas amphipods seem to be mainly raptorial feeders. The dominant krill, Thysanoessa inermis, is primarily regarded as an herbivore feeding mostly on diatoms. Alternatively, Thysanoessa longicaudata fed occasionally on calanoid copepods in addition to being a suspension feeder on phytoplankton. The largest of the krill species, Meganyctiphanes norvegica, showed a mixed diet with regular feeding on calanoid copepods and phytoplankton. The degree of carnivory varied between stations and was determined by examining the size and shape of the mandible of copepods. M. norvegica, with a total length of between 26 and 41 mm, had up to two copepods in their stomachs, with a mandible width of the copepods varying from 32 to 154 μm, corresponding, respectively, to a computed prosome length of 0.3 and 2.6 mm. Themisto libellula fed primarily on C3 and C4 copepodite stages of Calanus glacialis and Calanus hyperboreus, and up to three copepods were found in the stomach contents of T. libellula. Themisto abyssorum fed on herbivorous and omnivorous prey such as copepods and appendicularians. The presence of Metridia spp. and appendicularians, e.g., Oikopleura vanhoeffeni in the diet of T. abyssorum may indicate feeding in the deeper layers (>200 m).

  8. Screening differentially expressed genes in an amphipod (Hyalella azteca) exposed to fungicide vinclozolin by suppression subtractive hybridization.

    PubMed

    Wu, Yun H; Wu, Tsung M; Hong, Chwan Y; Wang, Yei S; Yen, Jui H

    2014-01-01

    Vinclozolin, a dicarboximide fungicide, is an endocrine disrupting chemical that competes with an androgenic endocrine disruptor compound. Most research has focused on the epigenetic effect of vinclozolin in humans. In terms of ecotoxicology, understanding the effect of vinclozolin on non-target organisms is important. The expression profile of a comprehensive set of genes in the amphipod Hyalella azteca exposed to vinclozolin was examined. The expressed sequence tags in low-dose vinclozolin-treated and -untreated amphipods were isolated and identified by suppression subtractive hybridization. DNA dot blotting was used to confirm the results and establish a subtracted cDNA library for comparing all differentially expressed sequences with and without vinclozolin treatment. In total, 494 differentially expressed genes, including hemocyanin, heatshock protein, cytochrome, cytochrome oxidase and NADH dehydrogenase were detected. Hemocyanin was the most abundant gene. DNA dot blotting revealed 55 genes with significant differential expression. These genes included larval serum protein 1 alpha, E3 ubiquitin-protein ligase, mitochondrial cytochrome c oxidase, mitochondrial protein, proteasome inhibitor, hemocyanin, zinc-finger-containing protein, mitochondrial NADH-ubiquinone oxidoreductase and epididymal sperm-binding protein. Vinclozolin appears to upregulate stress-related genes and hemocyanin, related to immunity. Moreover, vinclozolin downregulated NADH dehydrogenase, related to respiration. Thus, even a non-lethal concentration of vinclozolin still has an effect at the genetic level in H. azteca and presents a potential risk, especially as it would affect non-target organism hormone metabolism.

  9. Using a spiked sediment bioassay to establish a no-effect concentration for dioxin exposure to the amphipod, Ampelisca abdita

    SciTech Connect

    Barber, T.R.; Chappie, D.J.; Duda, D.J.; Fuchsman, P.C.; Finley, B.L.

    1998-03-01

    A recent study conducted by the National Oceanic and Atmospheric Administration (NOAA) reported a highly significant correlation between 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) concentrations and amphipod (Ampelisca abdita) mortality in sediment samples collected from the lower Passaic River and Newark Bay. However, there is a paucity of data regarding the potential effects of 2,3,7,8-TCDD on benthic invertebrates under controlled laboratory exposures. In this study, 10-d whole-sediment bioassays using the marine amphipod A. abdita were conducted on spiked sediment samples representing a range of 2,3,7,8-TCDD concentrations. No effects on survival or growth relative to controls were observed at any test concentration. The highest 2,3,7,8-TCDD concentration reported from the NOAA study was 0.62 {micro}g/kg. Therefore, the lack of 2,3,7,8-TCDD toxicity in this study indicates that the mortality observed in the NOAA study was probably due to factors or chemicals other than 2,3,7,8-TCDD. This study demonstrates the utility of spiked sediment bioassays in evaluating cause and effect relationships between sediment contamination and benthic invertebrate mortality.

  10. First finding of the amphipod Echinogammarus ischnus and the mussel Dreissena bugensis in Lake Michigan

    USGS Publications Warehouse

    Nalepa, Thomas F.; Schloesser, Don W.; Pothoven, Steve A.; Hondorp, Darryl W.; Fanslow, David L.; Tuchman, Marc L.; Fleischer, Guy W.

    2001-01-01

    The first finding of the amphipod Echinogammarus ischnus and the mussel Dreissena bugensis in Lake Michigan is documented. These two species are widespread and abundant in the lower lakes, but had not yet been reported from Lake Michigan. E. ischnus is generally considered a warm-water form that is typically associated wtih hard substrates and Dreissena clusters in the nearshore zone. Along the eastern shoreline of Lake Michigan, this species was present at rocky, breakwall habitats, along the entire north-south axis of the lake. Although not abundant, this species was also found at soft-bottom sites as deep as 94 m in the southern basin. The finding of this species in deep offshore waters apparently extends the known habitat range for this species in the Great Lakes, but it is found in deep water areas within its native range (Caspian Sea). D. bugensis was not abundant, but was present in both the southern and northern portions of the lake. Individuals of up to 36 mm in length were collected, indicating that it had probably been present in the lake for 2 or more years. Also presented are depth-defined densities of D. polymorpha at 37 sites in the Straits of Mackinac in 1997, and densities at up to 55 sites in the southern basin in 1992/93 and 1998/99. Mean densities decreased with increased water depth in both regions. Maximum mean density in the Straits in 1997 was 13,700/mA? (a?? 10 m), and maximum density in the southern basin in 1999 was 2,100/mA? (a?? 30 m). Mean densities at the a?? 30-m interval in the southern basin remained relatively unchanged between 1993 and 1999, but increased from 25/mA? to 1,100/mA? at the 31 to 50 m interval over the same time period. D. polymorpha was rare at sites > 50 m. The presence of E. ischnus and the expected population expansion of D. bugensis will likely contribute to further foodweb changes in the lake.

  11. Identification and temporal expression of putative circadian clock transcripts in the amphipod crustacean Talitrus saltator

    PubMed Central

    O’Grady, Joseph F.; Hoelters, Laura S.; Swain, Martin T.

    2016-01-01

    Background Talitrus saltator is an amphipod crustacean that inhabits the supralittoral zone on sandy beaches in the Northeast Atlantic and Mediterranean. T. saltator exhibits endogenous locomotor activity rhythms and time-compensated sun and moon orientation, both of which necessitate at least one chronometric mechanism. Whilst their behaviour is well studied, currently there are no descriptions of the underlying molecular components of a biological clock in this animal, and very few in other crustacean species. Methods We harvested brain tissue from animals expressing robust circadian activity rhythms and used homology cloning and Illumina RNAseq approaches to sequence and identify the core circadian clock and clock-related genes in these samples. We assessed the temporal expression of these genes in time-course samples from rhythmic animals using RNAseq. Results We identified a comprehensive suite of circadian clock gene homologues in T. saltator including the ‘core’ clock genes period (Talper), cryptochrome 2 (Talcry2), timeless (Taltim), clock (Talclk), and bmal1 (Talbmal1). In addition we describe the sequence and putative structures of 23 clock-associated genes including two unusual, extended isoforms of pigment dispersing hormone (Talpdh). We examined time-course RNAseq expression data, derived from tissues harvested from behaviourally rhythmic animals, to reveal rhythmic expression of these genes with approximately circadian period in Talper and Talbmal1. Of the clock-related genes, casein kinase IIβ (TalckIIβ), ebony (Talebony), jetlag (Taljetlag), pigment dispensing hormone (Talpdh), protein phosphatase 1 (Talpp1), shaggy (Talshaggy), sirt1 (Talsirt1), sirt7 (Talsirt7) and supernumerary limbs (Talslimb) show temporal changes in expression. Discussion We report the sequences of principle genes that comprise the circadian clock of T. saltator and highlight the conserved structural and functional domains of their deduced cognate proteins. Our

  12. Effect of diet quality on chronic toxicity of aqueous lead to the amphipod Hyalella azteca

    USGS Publications Warehouse

    Besser, John M.; Ivey, Chris D.; Brumbaugh, William G.; Ingersoll, Christopher G.

    2016-01-01

    The authors investigated the chronic toxicity of aqueous Pb to the amphipod Hyalella azteca (Hyalella) in 42-d tests using 2 different diets: 1) the yeastþcereal leafþtrout pellet (YCT) diet, fed at the uniform low ration used in standard methods for sediment toxicity tests; and 2) a new diet of diatomsþTetraMin flakes (DT), fed at increasing rations over time, that has been optimized for use in Hyalella water-only tests. Test endpoints included survival, weight, biomass, fecundity, and total young. Lethal effects of Pb were similar for the DT and YCT tests (20% lethal concentration [LC20]¼13 mg/L and 15mg/L, respectively, as filterable Pb). In contrast, weight and fecundity endpoints were not significantly affected in the DT test at Pb concentrations up to 63 mg/L, but these endpoints were significantly reduced by Pb in the YCT test—and in a 2005 test in the same laboratory with a diet of conditioned Rabbit Chow (RC-2005). The fecundity and total young endpoints from the YCT and RC-2005 tests were considered unreliable because fecundity in controls did not meet test acceptability criteria, but both of these tests still produced lower Pb effect concentrations (for weight or biomass) than the test with the DT diet. The lowest biotic ligand model–normalized effect concentrations for the 3 tests ranged from 3.7mg/L (weight 20% effect concentration [EC20] for the RC-2005 test) to 8.2 mg/L (total young EC20 for the DT test), values that would rank Hyalella as the second or third most sensitive of 13 genera in a species sensitivity distribution for chronic Pb toxicity. These results demonstrate that toxicity tests with Hyalella fed optimal diets can meet more stringent test acceptability criteria for control performance, but suggest that results of these tests may underestimate sublethal toxic effects of Pb to Hyalella under suboptimal feeding regimes.

  13. Optimizing the performance of the amphipod, Hyalella azteca, in chronic toxicity tests: Results of feeding studies with various foods and feeding regimes

    EPA Science Inventory

    The freshwater amphipod, Hyalella azteca, is a common organism used for sediment toxicity testing. Standard methods for 10-d and 42-d sediment toxicity tests with H. azteca were last revised and published by USEPA/ASTM in 2000. While Hyalella azteca methods exist for sediment tox...

  14. Testing for the induction of anti-herbivory defences in four Portuguese macroalgae by direct and water-borne cues of grazing amphipods

    NASA Astrophysics Data System (ADS)

    Yun, Hee Young; Cruz, Joana; Treitschke, Michaela; Wahl, Martin; Molis, Markus

    2007-09-01

    Herbivory is a key factor in regulating plant biomass, thereby driving ecosystem performance. Algae have developed multiple adaptations to cope with grazers, including morphological and chemical defences. In a series of experiments we investigated whether several species of macroalgae possess anti-herbivore defences and whether these could be regulated to demand, i.e. grazing events. The potential of direct grazing on defence induction was assessed for two brown ( Dictyopteris membranacea, Fucus vesiculosus) and two red seaweeds ( Gelidium sesquipedale, Sphaerococcus coronopifolius) from São Rafael and Ria Formosa, Portugal. Bioassays conducted with live algal pieces and agar-based food containing lipophilic algal extracts were used to detect changes in palatability after exposure to amphipod attacks (=treatment phase). Fucus vesiculosus was the only species significantly reducing palatability in response to direct amphipod-attacks. This pattern was observed in live F. vesiculosus pieces and agar-based food containing a lipophilic extract, suggesting that lipophilic compounds produced during the treatment phase were responsible for the repulsion of grazers. Water-borne cues of grazed F. vesiculosus as well as non-grazing amphipods also reduced palatability of neighbouring conspecifics. However, this effect was only observed in live tissues of F. vesiculosus. This study is the first to show that amphipods, like isopods, are capable to induce anti-herbivory defences in F. vesiculosus and that a seasonally variable effectiveness of chemical defences might serve as a dynamic control in alga-herbivore interactions.

  15. Behavioural and Physiological Responses of Gammarus pulex Exposed to Cadmium and Arsenate at Three Temperatures: Individual and Combined Effects

    PubMed Central

    Vellinger, Céline; Felten, Vincent; Sornom, Pascal; Rousselle, Philippe; Beisel, Jean-Nicolas; Usseglio-Polatera, Philippe

    2012-01-01

    This study aimed at investigating both the individual and combined effects of cadmium (Cd) and arsenate (AsV) on the physiology and behaviour of the Crustacean Gammarus pulex at three temperatures (5, 10 and15°C). G. pulex was exposed during 96 h to (i) two [Cd] alone, (ii) two [AsV] alone, and (iii) four combinations of [Cd] and [AsV] to obtain a complete factorial plane. After exposure, survival, [AsV] or [Cd] in body tissues, behavioural (ventilatory and locomotor activities) and physiological responses (iono-regulation of [Na+] and [Cl−] in haemolymph) were examined. The interactive effects (antagonistic, additive or synergistic) of binary mixtures were evaluated for each tested temperature using a predictive model for the theoretically expected interactive effect of chemicals. In single metal exposure, both the internal metal concentration in body tissues and the mortality rate increased along metallic gradient concentration. Cd alone significantly impaired both [Na+] and [Cl−] while AsV alone had a weak impact only on [Cl−]. The behavioural responses of G. pulex declined with increasing metal concentration suggesting a reallocation of energy from behavioural responses to maintenance functions. The interaction between AsV and Cd was considered as ‘additive’ for all the tested binary mixtures and temperatures (except for the lowest combination at 10°C considered as “antagonistic”). In binary mixtures, the decrease in both ventilatory and locomotor activities and the decline in haemolymphatic [Cl−] were amplified when respectively compared to those observed with the same concentrations of AsV or Cd alone. However, the presence of AsV decreased the haemolymphatic [Na+] loss when G. pulex was exposed to the lowest Cd concentration. Finally, the observed physiological and behavioural effects (except ventilation) in G. pulex exposed to AsV and/or Cd were exacerbated under the highest temperature. The discussion encompasses both the toxicity

  16. Methyl mercury inhibits short-circuit current and Cl- influx across isolated epipodite of European lobster (Homarus gammarus).

    PubMed

    Lucu, Cedomil; Dupcić-Radić, Iris; Tomsić, Sanja

    2009-05-01

    The effect of methyl mercuric chloride (MeHg) on short-circuit current (I(SC)) was studied in the isolated perfused epipodite preparation from the branchial chamber of European lobster (Homarus gammarus) acclimated to dilute seawater. When applied at the apical surface, 0.2, 1.0 and 3.0 microM MeHg depressed I(SC) by a 26%, 81% and 98%, respectively. The half-maximal inhibitory concentration (IC(50)) of apically applied MeHg was 0.6 microM. Basolaterally added MeHg (3.0 microM) had no effect on I(SC), whereas addition of the specific Na(+),K(+)-ATPase inhibitor ouabain (1.5 mM) reduced I(SC) by approximately 90%. Ouabain effects were reversible, and I(SC) fully recovered upon removal of ouabain. The MeHg-induced block of I(SC) was partially reversed by the reducing agent, 1,4-dithiothreitol, suggesting that the formation of S-Hg-S bridges is important in the inhibitory mechanism. A significant reduction of I(SC) and conductance occurred when low Na(+) and Cl(-) salines were substituted. Furthermore, in the low Na(+) saline, J(Cl)(A-->B) fluxes were reduced by about 50%. In the highly conductive epipodite epithelium, coupling of Na(+) and Cl(-) fluxes was suggested. The effects of MeHg on I(SC) in the lobster epipodite are attributed to inhibition of an apical Cl(-) influx. PMID:19038364

  17. Identification and expression of mRNAs encoding bursicon in the plesiomorphic central nervous system of Homarus gammarus.

    PubMed

    Sharp, Jasmine H; Wilcockson, David C; Webster, Simon G

    2010-10-01

    Ecdysis in arthropods is a complex process, regulated by many neurohormones, which must be released in a precisely coordinated manner. In insects, the ultimate hormone involved in this process is the cuticle tanning hormone, bursicon. Recently, this hormone has been identified in crustaceans. To further define the distribution of bursicon in crustacean nervous systems, and to compare hormone structures within the sub-phylum, cDNAs encoding both bursicon subunits were cloned and sequenced from the nervous system of the European lobster, Homarus gammarus, and expression patterns including those for CCAP determined using in-situ hybridisation, quantitative RT-PCR and immunohistochemistry. Full-length cDNAs encoded bursicon subunits of 121 amino acids (Average M(r): 13365.48) for Burs α, 115 amino acids (Average M(r): 12928.54) for Burs β. Amino acid sequences were most closely related to those of crabs, and for Burs β the sequence was identical to that of the American lobster, Homarus americanus. Complete co-localisation with CCAP in the VNC was seen. Copy numbers burs α, burs β and CCAP mRNAs were between 0.5 and 1.5 × 10(5) for both bursicon subunits, 0.5-6 × 10(5) per cdn neurone for CCAP. The terminal abdominal ganglia (AG 6-8) contained about 52 cdn-type neurons, making it the largest bursicon producing region in the CNS. Double labelling IHC using recombinant Carcinus Burs α and CCAP antisera demonstrated complete co-localisation in the VNC. On the basis of the results obtained, it is proposed that CCAP and bursicon release occur simultaneously during ecdysis in crustaceans. PMID:20691691

  18. Bioaccumulation of Toxoplasma and Cryptosporidium by the freshwater crustacean Gammarus fossarum: Involvement in biomonitoring surveys and trophic transfer.

    PubMed

    Bigot-Clivot, Aurélie; Palos Ladeiro, Mélissa; Lepoutre, Alexandra; Bastien, Fanny; Bonnard, Isabelle; Dubey, Jitender P; Villena, Isabelle; Aubert, Dominique; Geffard, Olivier; François, Adeline; Geffard, Alain

    2016-11-01

    The protozoa Toxoplasma gondii and Cryptosporidium parvum are public health priorities because their oocysts can persist in recreational, surface, drinking, river, and sea water sources for a long time. To evaluate the capacity of the freshwater crustacean Gammarus fossarum to accumulate T. gondii and C. parvum oocysts, gammarids were exposed to 200, 2000 or 20,000 oocysts per gammarid and per day for 21 days followed by 5 days of depuration. C. parvum DNA was detected by qPCR in G. fossarum in only one out of four pools for the highest concentration and after 14 days of exposure, and T. gondii DNA was detected after 7 days of exposure to the two highest concentrations. Our results document the capacity of G. fossarum to accumulate T. gondii in its tissues proportionally to the ambient concentration; the maximum number of oocysts was detected in gammarid tissues after exposure to 20,000 oocysts per day. Mean values of 3.26 (±3), 21.71 (±15.18), and 17.41 (±10.89) oocysts were detected in gammarids after 7, 14, and 21 days, respectively, and after 5 days of depuration, T. gondii oocysts were still present in gammarid tissues. These results show for the first time that a freshwater crustacean can bioaccumulate T. gondii oocysts, suggesting that G. fossarum is a potential effective bioindicator of protozoan contamination in biomonitoring studies. Moreover, due to its key position in freshwater food webs, G. fossarum could also play a role in the trophic transfer of protozoa. PMID:27454203

  19. The supergiant amphipod Alicella gigantea (Crustacea: Alicellidae) from hadal depths in the Kermadec Trench, SW Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Jamieson, A. J.; Lacey, N. C.; Lörz, A.-N.; Rowden, A. A.; Piertney, S. B.

    2013-08-01

    Here we provide the first record of the 'supergiant' amphipod Alicella gigantea Chevreux, 1899 (Alicellidae) from the Southern Hemisphere, and extend the known bathymetric range by over 1000 m to 7000 m. An estimated nine individuals were observed across 1500 photographs taken in situ by baited camera at 6979 m in the Kermadec Trench, SW Pacific Ocean. Nine specimens, ranging in length from 102 to 290 mm were recovered by baited trap at depths of 6265 m and 7000 m. Mitochondrial and nuclear DNA sequences obtained indicate a cosmopolitan distribution for the species. Data and observations from the study are used to discuss the reason for gigantism in this species, and its apparently disjunct geographical distribution.

  20. Shallow water marine gammaridean amphipods of Pulau Tioman, Malaysia, with the description of a new species

    PubMed Central

    Azman, B.A.R.; Othman, B.H.R.

    2013-01-01

    Abstract Eleven taxa including one new species of gammaridean amphipods are reported from the waters of Pulau Tioman. The presence of Tethygeneia sunda sp. n. represents the first record of the genus from the South China Sea. Additional material of Ampelisca brevicornis (Costa, 1853); Cymadusa vadosa Imbach, 1967; Paradexamine setigera Hirayama, 1984; Ericthonius pugnax (Dana, 1853); Leucothoe furina (Savigny, 1816); Microlysias xenokeras (Stebbing, 1918); Monoculodes muwoni Jo, 1990 are identified from the South China Sea, supporting previous records by Lowry (2000), Huang (1994), Imbach (1967), Margulis (1968) and Nagata (1959). Three additional species, Gitanopsis pusilla K.H. Barnard, 1916, Liljeborgia japonica Nagata, 1965b and Latigammaropsis atlantica (Stebbing, 1888), whilst previously reported from the neighbouring waters, comprise new records for the South China Sea. PMID:24146563

  1. Shallow water marine gammaridean amphipods of Pulau Tioman, Malaysia, with the description of a new species.

    PubMed

    Azman, B A R; Othman, B H R

    2013-01-01

    Eleven taxa including one new species of gammaridean amphipods are reported from the waters of Pulau Tioman. The presence of Tethygeneia sunda sp. n. represents the first record of the genus from the South China Sea. Additional material of Ampelisca brevicornis (Costa, 1853); Cymadusa vadosa Imbach, 1967; Paradexamine setigera Hirayama, 1984; Ericthonius pugnax (Dana, 1853); Leucothoe furina (Savigny, 1816); Microlysias xenokeras (Stebbing, 1918); Monoculodes muwoni Jo, 1990 are identified from the South China Sea, supporting previous records by Lowry (2000), Huang (1994), Imbach (1967), Margulis (1968) and Nagata (1959). Three additional species, Gitanopsis pusilla K.H. Barnard, 1916, Liljeborgia japonica Nagata, 1965b and Latigammaropsis atlantica (Stebbing, 1888), whilst previously reported from the neighbouring waters, comprise new records for the South China Sea.

  2. Effects of seawater alkalinity on calcium and acid-base regulation in juvenile European lobster (Homarus gammarus) during a moult cycle.

    PubMed

    Middlemiss, Karen L; Urbina, Mauricio A; Wilson, Rod W

    2016-03-01

    Fluxes of NH4(+) (acid) and HCO3(-) (base), and whole body calcium content were measured in European lobster (Homarus gammarus) during intermoult (megalopae stage), and during the first 24h for postmoult juveniles under control (~2000 μeq/L) and low seawater alkalinity (~830 μeq/L). Immediately after moulting, animals lost 45% of the total body calcium via the shed exoskeleton (exuvia), and only 11% was retained in the uncalcified body. At 24h postmoult, exoskeleton calcium increased to ~46% of the intermoult stage. Ammonia excretion was not affected by seawater alkalinity. After moulting, bicarbonate excretion was immediately reversed from excretion to uptake (~4-6 fold higher rates than intermoult) over the whole 24h postmoult period, peaking at 3-6h. These data suggest that exoskeleton calcification is not completed by 24h postmoult. Low seawater alkalinity reduced postmoult bicarbonate uptake by 29% on average. Net acid-base flux (equivalent to net base uptake) followed the same pattern as HCO3(-) fluxes, and was 22% lower in low alkalinity seawater over the whole 24h postmoult period. The common occurrence of low alkalinity in intensive aquaculture systems may slow postmoult calcification in juvenile H. gammarus, increasing the risk of mortalities through cannibalism.

  3. A marriage of convenience; a simple food chain comprised of Lemna minor (L.) and Gammarus pulex (L.) to study the dietary transfer of zinc.

    PubMed

    Lahive, E; O'Halloran, J; Jansen, M A K

    2015-01-01

    Macrophytes contribute significantly to the cycling of metals in aquatic systems, through accumulation during growth and release during herbivory or decomposition. Accumulation of high levels of metals has been extensively documented in Lemnaceae (duckweeds). However, the degree of trophic transfer of metals from Lemnaceae to secondary consumers remains poorly understood. This study demonstrates that zinc accumulated in Lemna minor is bioavailable to the herbivore consumer Gammarus pulex. Overall, the higher the zinc content of L. minor, the more zinc accumulated in G. pulex. Accumulation in G. pulex was such that mortality occurred when they were fed high zinc-containing L. minor. Yet, the percentage of consumed zinc retained by G. pulex actually decreased with higher zinc concentrations in L. minor. We hypothesise that this decrease reflects internal zinc metabolism, including a shift from soluble to covalently bound zinc in high zinc-containing L. minor. Consistently, relatively more zinc is lost through depuration when G. pulex is fed L. minor with high zinc content. The developed Lemna-Gammarus system is simple, easily manipulated, and sensitive enough for changes in plant zinc metabolism to be reflected in metal accumulation by the herbivore, and therefore suitable to study ecologically relevant metal cycling in aquatic ecosystems.

  4. The proteasomes of two marine decapod crustaceans, European lobster (Homarus gammarus) and Edible crab (Cancer pagurus), are differently impaired by heavy metals.

    PubMed

    Götze, Sandra; Bose, Aneesh; Sokolova, Inna M; Abele, Doris; Saborowski, Reinhard

    2014-05-01

    The intracellular ubiquitin-proteasome system is a key regulator of cellular processes involved in the controlled degradation of short-living or malfunctioning proteins. Certain diseases and cellular dysfunctions are known to arise from the disruption of proteasome pathways. Trace metals are recognized stressors of the proteasome system in vertebrates and plants, but their effects on the proteasome of invertebrates are not well understood. Since marine invertebrates, and particularly benthic crustaceans, can be exposed to high metal levels, we studied the effects of in vitro exposure to Hg(2+), Zn(2+), Cu(2+), and Cd(2+) on the activities of the proteasome from the claw muscles of lobsters (Homarus gammarus) and crabs (Cancer pagurus). The chymotrypsin like activity of the proteasome of these two species showed different sensitivity to metals. In lobsters the activity was significantly inhibited by all metals to a similar extent. In crabs the activities were severely suppressed only by Hg(2+) and Cu(2+) while Zn(2+) had only a moderate effect and Cd(2+) caused almost no inhibition of the crab proteasome. This indicates that the proteasomes of both species possess structural characteristics that determine different susceptibility to metals. Consequently, the proteasome-mediated protein degradation in crab C. pagurus may be less affected by metal pollution than that of the lobster H. gammarus. PMID:24721378

  5. The proteasomes of two marine decapod crustaceans, European lobster (Homarus gammarus) and Edible crab (Cancer pagurus), are differently impaired by heavy metals.

    PubMed

    Götze, Sandra; Bose, Aneesh; Sokolova, Inna M; Abele, Doris; Saborowski, Reinhard

    2014-05-01

    The intracellular ubiquitin-proteasome system is a key regulator of cellular processes involved in the controlled degradation of short-living or malfunctioning proteins. Certain diseases and cellular dysfunctions are known to arise from the disruption of proteasome pathways. Trace metals are recognized stressors of the proteasome system in vertebrates and plants, but their effects on the proteasome of invertebrates are not well understood. Since marine invertebrates, and particularly benthic crustaceans, can be exposed to high metal levels, we studied the effects of in vitro exposure to Hg(2+), Zn(2+), Cu(2+), and Cd(2+) on the activities of the proteasome from the claw muscles of lobsters (Homarus gammarus) and crabs (Cancer pagurus). The chymotrypsin like activity of the proteasome of these two species showed different sensitivity to metals. In lobsters the activity was significantly inhibited by all metals to a similar extent. In crabs the activities were severely suppressed only by Hg(2+) and Cu(2+) while Zn(2+) had only a moderate effect and Cd(2+) caused almost no inhibition of the crab proteasome. This indicates that the proteasomes of both species possess structural characteristics that determine different susceptibility to metals. Consequently, the proteasome-mediated protein degradation in crab C. pagurus may be less affected by metal pollution than that of the lobster H. gammarus.

  6. Stage-Specific Changes in Physiological and Life-History Responses to Elevated Temperature and Pco2 during the Larval Development of the European Lobster Homarus gammarus (L.).

    PubMed

    Small, Daniel P; Calosi, Piero; Boothroyd, Dominic; Widdicombe, Steve; Spicer, John I

    2015-01-01

    An organism's physiological processes form the link between its life-history traits and the prevailing environmental conditions, especially in species with complex life cycles. Understanding how these processes respond to changing environmental conditions, thereby affecting organismal development, is critical if we are to predict the biological implications of current and future global climate change. However, much of our knowledge is derived from adults or single developmental stages. Consequently, we investigated the metabolic rate, organic content, carapace mineralization, growth, and survival across each larval stage of the European lobster Homarus gammarus, reared under current and predicted future ocean warming and acidification scenarios. Larvae exhibited stage-specific changes in the temperature sensitivity of their metabolic rate. Elevated Pco2 increased C∶N ratios and interacted with elevated temperature to affect carapace mineralization. These changes were linked to concomitant changes in survivorship and growth, from which it was concluded that bottlenecks were evident during H. gammarus larval development in stages I and IV, the transition phases between the embryonic and pelagic larval stages and between the larval and megalopa stages, respectively. We therefore suggest that natural changes in optimum temperature during ontogeny will be key to larvae survival in a future warmer ocean. The interactions of these natural changes with elevated temperature and Pco2 significantly alter physiological condition and body size of the last larval stage before the transition from a planktonic to a benthic life style. Thus, living and growing in warm, hypercapnic waters could compromise larval lobster growth, development, and recruitment.

  7. A marriage of convenience; a simple food chain comprised of Lemna minor (L.) and Gammarus pulex (L.) to study the dietary transfer of zinc.

    PubMed

    Lahive, E; O'Halloran, J; Jansen, M A K

    2015-01-01

    Macrophytes contribute significantly to the cycling of metals in aquatic systems, through accumulation during growth and release during herbivory or decomposition. Accumulation of high levels of metals has been extensively documented in Lemnaceae (duckweeds). However, the degree of trophic transfer of metals from Lemnaceae to secondary consumers remains poorly understood. This study demonstrates that zinc accumulated in Lemna minor is bioavailable to the herbivore consumer Gammarus pulex. Overall, the higher the zinc content of L. minor, the more zinc accumulated in G. pulex. Accumulation in G. pulex was such that mortality occurred when they were fed high zinc-containing L. minor. Yet, the percentage of consumed zinc retained by G. pulex actually decreased with higher zinc concentrations in L. minor. We hypothesise that this decrease reflects internal zinc metabolism, including a shift from soluble to covalently bound zinc in high zinc-containing L. minor. Consistently, relatively more zinc is lost through depuration when G. pulex is fed L. minor with high zinc content. The developed Lemna-Gammarus system is simple, easily manipulated, and sensitive enough for changes in plant zinc metabolism to be reflected in metal accumulation by the herbivore, and therefore suitable to study ecologically relevant metal cycling in aquatic ecosystems. PMID:24731282

  8. Stage-Specific Changes in Physiological and Life-History Responses to Elevated Temperature and Pco2 during the Larval Development of the European Lobster Homarus gammarus (L.).

    PubMed

    Small, Daniel P; Calosi, Piero; Boothroyd, Dominic; Widdicombe, Steve; Spicer, John I

    2015-01-01

    An organism's physiological processes form the link between its life-history traits and the prevailing environmental conditions, especially in species with complex life cycles. Understanding how these processes respond to changing environmental conditions, thereby affecting organismal development, is critical if we are to predict the biological implications of current and future global climate change. However, much of our knowledge is derived from adults or single developmental stages. Consequently, we investigated the metabolic rate, organic content, carapace mineralization, growth, and survival across each larval stage of the European lobster Homarus gammarus, reared under current and predicted future ocean warming and acidification scenarios. Larvae exhibited stage-specific changes in the temperature sensitivity of their metabolic rate. Elevated Pco2 increased C∶N ratios and interacted with elevated temperature to affect carapace mineralization. These changes were linked to concomitant changes in survivorship and growth, from which it was concluded that bottlenecks were evident during H. gammarus larval development in stages I and IV, the transition phases between the embryonic and pelagic larval stages and between the larval and megalopa stages, respectively. We therefore suggest that natural changes in optimum temperature during ontogeny will be key to larvae survival in a future warmer ocean. The interactions of these natural changes with elevated temperature and Pco2 significantly alter physiological condition and body size of the last larval stage before the transition from a planktonic to a benthic life style. Thus, living and growing in warm, hypercapnic waters could compromise larval lobster growth, development, and recruitment. PMID:26658247

  9. Effects of seawater alkalinity on calcium and acid-base regulation in juvenile European lobster (Homarus gammarus) during a moult cycle.

    PubMed

    Middlemiss, Karen L; Urbina, Mauricio A; Wilson, Rod W

    2016-03-01

    Fluxes of NH4(+) (acid) and HCO3(-) (base), and whole body calcium content were measured in European lobster (Homarus gammarus) during intermoult (megalopae stage), and during the first 24h for postmoult juveniles under control (~2000 μeq/L) and low seawater alkalinity (~830 μeq/L). Immediately after moulting, animals lost 45% of the total body calcium via the shed exoskeleton (exuvia), and only 11% was retained in the uncalcified body. At 24h postmoult, exoskeleton calcium increased to ~46% of the intermoult stage. Ammonia excretion was not affected by seawater alkalinity. After moulting, bicarbonate excretion was immediately reversed from excretion to uptake (~4-6 fold higher rates than intermoult) over the whole 24h postmoult period, peaking at 3-6h. These data suggest that exoskeleton calcification is not completed by 24h postmoult. Low seawater alkalinity reduced postmoult bicarbonate uptake by 29% on average. Net acid-base flux (equivalent to net base uptake) followed the same pattern as HCO3(-) fluxes, and was 22% lower in low alkalinity seawater over the whole 24h postmoult period. The common occurrence of low alkalinity in intensive aquaculture systems may slow postmoult calcification in juvenile H. gammarus, increasing the risk of mortalities through cannibalism. PMID:26691956

  10. Mortality and deformities in European lobster (Homarus gammarus) juveniles exposed to the anti-parasitic drug teflubenzuron.

    PubMed

    Samuelsen, Ole B; Lunestad, Bjørn T; Farestveit, Eva; Grefsrud, Ellen S; Hannisdal, Rita; Holmelid, Bjarte; Tjensvoll, Tore; Agnalt, Ann-Lisbeth

    2014-04-01

    This study describes experiments carried out to examine effects of the antiparasitic drug teflubenzuron, used in delousing farmed salmon, on a non-target species, the European lobster (Homarus gammarus). Juvenile lobsters were fed two doses of teflubenzuron, 10 and 20mg/kg successively for 7 days corresponding to a standard medication of the fish (10mg/kg day) and twice the standard dose (20mg/kg day). Monitoring lasted 3 months to include at least one moulting period for all individuals. Cumulative mortality was higher in all replicates given medicated feed compared with the control group. Mean cumulative mortality for each dosing was 41 ± 13% for 10mg/kg and 38 ± 8% for 20mg/kg, i.e. no difference. Drug residue was analysed in all juveniles that died, in addition to 12 juveniles at day 8 and the first 12 surviving lobsters. A decline in concentration of teflubenzuron from over 8,000 ng/g (day 5) to 14 ng/g (day 70) was observed in the juveniles that died during the experiment. Twelve individuals that died contained 82 ng/g or less whereas the mean concentration in the first 12 lobsters that survived moulting was 152 ng/g. Following a single oral administration, the half-life of teflubenzuron in lobster was estimated to 3.4 days and the initial concentration (C0) to 515 ng/g at time t0. At the end of the study a considerable number of juvenile lobsters were observed with deformities in various organs; carapace, walking legs, cheliped, tail fan, abdomen and antenna. The occurrence of observed deformities varied from 0 to 15% in treated replicates and will most likely affect ability to locate and consume food (antenna, claw and walking legs), respiration (carapace) and ability to move/swim (walking legs, tail fan and abdomen). In total, the mortality and senescent damages were close to 50% in all replicates. Juveniles that survived medication without deformities however, moulted and increased in size at each moult equally well as the unmedicated controls. PMID

  11. Deformities in larvae and juvenile European lobster (Homarus gammarus) exposed to lower pH at two different temperatures

    NASA Astrophysics Data System (ADS)

    Agnalt, A.-L.; Grefsrud, E. S.; Farestveit, E.; Larsen, M.; Keulder, F.

    2013-05-01

    Trends of increasing temperatures and ocean acidification are expected to influence benthic marine resources, especially calcifying organisms. The European lobster (Homarus gammarus) is among those species at risk. A project was initiated in 2011 aiming to investigate long-term synergistic effects of temperature and projected increases in ocean acidification on the life cycle of lobster. Larvae were exposed to pCO2 levels of ambient water (water intake at 90 m depth, tentatively of 380 μatm pCO2), 727 and 1217 μatm pCO2, at temperatures 10 and 18 °C. Long-term exposure lasted until 5 months of age. Thereafter the surviving juveniles were transferred to ambient water at 14 °C. At 18 °C the development from Stage 1 to 4 lasted from 14 to 16 days, as predicted under normal pH values. Growth was very slow at 10 °C and resulted in only two larvae reaching Stage 4 in the ambient treatment. There were no significant differences in carapace length at the various larval stages between the different treatments, but there were differences in total length and dry weight at Stage 1 at 10 °C, Stage 2 at both temperatures, producing larvae slightly larger in size and lighter by dry weight in the exposed treatments. Stage 3 larvae raised in 18 °C and 1217 μatm pCO2 were also larger in size and heavier by dry weight compared with 727 μatm. Unfortunate circumstances precluded a full comparison across stages and treatment. Deformities were however observed in both larvae and juveniles. At 10 °C, about 20% of the larvae exposed to elevated pCO2were deformed, compared with 0% in larvae raised in pH above 8.0. At 18 °C and in high pCO2 treatment, 31.5% of the larvae were deformed. Occurrence of deformities after 5 months of exposure was 33 and 44% in juveniles raised in ambient and low pCO2, respectively, and 20% in juveniles exposed to high pCO2. Some of the deformities will possibly affect the ability to find food, sexual partner (walking legs, claw and antenna

  12. Mortality and deformities in European lobster (Homarus gammarus) juveniles exposed to the anti-parasitic drug teflubenzuron.

    PubMed

    Samuelsen, Ole B; Lunestad, Bjørn T; Farestveit, Eva; Grefsrud, Ellen S; Hannisdal, Rita; Holmelid, Bjarte; Tjensvoll, Tore; Agnalt, Ann-Lisbeth

    2014-04-01

    This study describes experiments carried out to examine effects of the antiparasitic drug teflubenzuron, used in delousing farmed salmon, on a non-target species, the European lobster (Homarus gammarus). Juvenile lobsters were fed two doses of teflubenzuron, 10 and 20mg/kg successively for 7 days corresponding to a standard medication of the fish (10mg/kg day) and twice the standard dose (20mg/kg day). Monitoring lasted 3 months to include at least one moulting period for all individuals. Cumulative mortality was higher in all replicates given medicated feed compared with the control group. Mean cumulative mortality for each dosing was 41 ± 13% for 10mg/kg and 38 ± 8% for 20mg/kg, i.e. no difference. Drug residue was analysed in all juveniles that died, in addition to 12 juveniles at day 8 and the first 12 surviving lobsters. A decline in concentration of teflubenzuron from over 8,000 ng/g (day 5) to 14 ng/g (day 70) was observed in the juveniles that died during the experiment. Twelve individuals that died contained 82 ng/g or less whereas the mean concentration in the first 12 lobsters that survived moulting was 152 ng/g. Following a single oral administration, the half-life of teflubenzuron in lobster was estimated to 3.4 days and the initial concentration (C0) to 515 ng/g at time t0. At the end of the study a considerable number of juvenile lobsters were observed with deformities in various organs; carapace, walking legs, cheliped, tail fan, abdomen and antenna. The occurrence of observed deformities varied from 0 to 15% in treated replicates and will most likely affect ability to locate and consume food (antenna, claw and walking legs), respiration (carapace) and ability to move/swim (walking legs, tail fan and abdomen). In total, the mortality and senescent damages were close to 50% in all replicates. Juveniles that survived medication without deformities however, moulted and increased in size at each moult equally well as the unmedicated controls.

  13. Determining the sensitivity of the Antarctic amphipod Orchomenella pinguides to metals using a joint model of survival response to exposure concentration and duration.

    PubMed

    Sfiligoj, Bianca J; King, Catherine K; Candy, Steven G; Mondon, Julie A

    2015-04-01

    Developing water quality guidelines for Antarctic marine environments requires understanding the sensitivity of local biota to contaminant exposure. Antarctic invertebrates have shown slower contaminant responses in previous experiments compared to temperate and tropical species in standard toxicity tests. Consequently, test methods which take into account environmental conditions and biological characteristics of cold climate species need to be developed. This study investigated the effects of five metals on the survival of a common Antarctic amphipod, Orchomenella pinguides. Multiple observations assessing mortality to metal exposure were made over the 30 days exposure period. Traditional toxicity tests with quantal data sets are analysed using methods such as maximum likelihood regression (probit analysis) and Spearman-Kärber which treat individual time period endpoints independently. A new statistical model was developed to integrate the time-series concentration-response data obtained in this study. Grouped survival data were modelled using a generalized additive mixed model (GAMM) which incorporates all the data obtained from multiple observation times to derive time integrated point estimates. The sensitivity of the amphipod, O. pinguides, to metals increased with increasing exposure time. Response times varied for different metals with amphipods responding faster to copper than to cadmium, lead or zinc. As indicated by 30 days lethal concentration (LC50) estimates, copper was the most toxic metal (31 µg/L), followed by cadmium (168 µg/L), lead (256 µg/L) and zinc (822 µg/L). Nickel exposure (up to 1.12 mg/L) did not affect amphipod survival. Using longer exposure durations and utilising the GAMM model provides an improved methodology for assessing sensitivities of slow responding Antarctic marine invertebrates to contaminants.

  14. Local effects of a global problem: modelling the risk of parasite-induced mortality in an intertidal trematode-amphipod system.

    PubMed

    Studer, A; Poulin, R; Tompkins, D M

    2013-08-01

    The interactive effects of climate change and parasitism are of concern because of potentially important consequences for host populations, communities and entire ecosystems. In marine environments, the absence of historic baseline data on parasitism and disease limits our ability to make realistic predictions about these consequences. Here, we adapt a simulation model developed for a Northern Hemisphere intertidal host-parasite system to a comparable system in the Southern Hemisphere. The entire life cycle of the intertidal trematode parasite Maritrema novaezealandensis was modelled in order to investigate the interactive effects of parasitic infections and increasing temperatures on the population dynamics of the amphipod host Paracalliope novizealandiae. Despite uncertainties associated with the model and its parameterisation, most temperature increases that were predicted to cause the collapse of the modelled amphipod population in the long term lay within the range of predicted warming for the study area. The high vulnerability of the amphipods in the modelled system illustrates a potentially important ecological mechanism by which consequences of a global problem might manifest on the local scale.

  15. Geographic range and structure of cryptic genetic diversity among Pacific North American populations of the non-native amphipod Grandidierella japonica

    USGS Publications Warehouse

    Pilgrim, Erik M.; Blum, Michael J.; Reusser, Deborah A.; Lee, Henry; Darling, John A.

    2013-01-01

    Reconstructing the invasion history of aquatic invasive species can enhance understanding of invasion risks by recognizing areas most susceptible to invasion and forecasting future spread based on past patterns of population expansion. Here we reconstruct the invasion history of the Japanese amphipod Grandidierella japonica Stephensen 1938 combining information from historical collection data with molecular genetic data to better understand post-invasion range expansion and anthropogenic connectivity across the Pacific coast of North America. Compilation of collection data from bays and estuaries of the Pacific North American coast show many new localities have been colonized in the last two decades, moving outward from harbors and bays with high commercial traffic into smaller coastal locations dominated by local recreational traffic. DNA barcode sequence data for G. japonica reveals two distinct clades: one found in San Francisco Bay and sites to the north, and one also found in San Francisco Bay and sites to the south. The two clades differ by an average 7.28 % genetic distance, large enough to consider these invasive amphipods two separate species. Both northern and southern clades exhibit low levels of genetic diversity, suggesting a single introduction event for each. The presence of cryptic diversity within this invasive amphipod highlights the need for more extensive study of the invasive and native populations of aquatic invasive invertebrates to address questions of taxonomy, diversity, and invasion history.

  16. Multi-annual fluctuations in reconstructed historical time-series of a European lobster (Homarus gammarus) population disappear at increased exploitation levels.

    PubMed

    Sundelöf, Andreas; Bartolino, Valerio; Ulmestrand, Mats; Cardinale, Massimiliano

    2013-01-01

    Through the history of ecology, fluctuations of populations have been a dominating topic, and endogenous causes of fluctuations and oscillations have been recognized and studied for more than 80 years. Here we analyzed an historical dataset, covering more than 130 years, of European lobster (Homarus gammarus) catches. The data shows periodic fluctuations, which are first dampened and then disappear over time. The disappearance of the periodicity coincided with a substantial increase in fishing effort and the oscillations have not reappeared in the time series. The shifting baseline syndrome has changed our perception of not only the status of the stock, but also the regulating pressures. We describe the transition of a naturally regulated lobster population into a heavily exploited fisheries controlled stock. This is shown by the incorporation of environmental and endogenous processes in generalized additive models, autocorrelation functions and periodicity analyses of time-series. PMID:23573187

  17. Multi-Annual Fluctuations in Reconstructed Historical Time-Series of a European Lobster (Homarus gammarus) Population Disappear at Increased Exploitation Levels

    PubMed Central

    Sundelöf, Andreas; Bartolino, Valerio; Ulmestrand, Mats; Cardinale, Massimiliano

    2013-01-01

    Through the history of ecology, fluctuations of populations have been a dominating topic, and endogenous causes of fluctuations and oscillations have been recognized and studied for more than 80 years. Here we analyzed an historical dataset, covering more than 130 years, of European lobster (Homarus gammarus) catches. The data shows periodic fluctuations, which are first dampened and then disappear over time. The disappearance of the periodicity coincided with a substantial increase in fishing effort and the oscillations have not reappeared in the time series. The shifting baseline syndrome has changed our perception of not only the status of the stock, but also the regulating pressures. We describe the transition of a naturally regulated lobster population into a heavily exploited fisheries controlled stock. This is shown by the incorporation of environmental and endogenous processes in generalized additive models, autocorrelation functions and periodicity analyses of time-series. PMID:23573187

  18. Susceptibility of juvenile European lobster Homarus gammarus to shrimp products infected with high and low doses of white spot syndrome virus.

    PubMed

    Bateman, K S; Munro, J; Uglow, B; Small, H J; Stentiford, G D

    2012-08-27

    White spot syndrome virus (WSSV) is the most important pathogen known to affect the sustainability and growth of the global penaeid shrimp farming industry. Although most commonly associated with penaeid shrimp farmed in warm waters, WSSV is also able to infect, cause disease in and kill a wide range of other decapod crustaceans, including lobsters, from temperate regions. In 2005, the European Union imported US$500 million worth of raw frozen or cooked frozen commodity products, much of which originated in regions positive for white spot disease (WSD). The presence of WSSV within the UK food market was verified by means of nested PCR performed on samples collected from a small-scale survey of supermarket commodity shrimp. Passage trials using inoculum derived from commodity shrimp from supermarkets and delivered by injection to specific pathogen-free Pacific white shrimp Litopenaeus vannamei led to rapid mortality and pathognomonic signs of WSD in the shrimp, demonstrating that WSSV present within commodity shrimp was viable. We exposed a representative European decapod crustacean, the European lobster Homarus gammarus, to a single feeding of WSSV-positive, supermarket-derived commodity shrimp, and to positive control material (L. vannamei infected with a high dose of WSSV). These trials demonstrated that lobsters fed positive control (high dose) frozen raw products succumbed to WSD and displayed pathognomonic signs associated with the disease as determined by means of histology and transmission electron microscopy. Lobsters fed WSSV-positive, supermarket-derived commodity shrimp (low dose) did not succumb to WSD (no mortality or pathognomonic signs of WSD) but demonstrated a low level or latent infection via PCR. This study confirms susceptibility of H. gammarus to WSSV via single feedings of previously frozen raw shrimp products obtained directly from supermarkets. PMID:23186704

  19. Stress proteins hsp60 and hsp70 in three species of amphipods exposed to cadmium, diazinon, dieldrin and fluoranthene

    SciTech Connect

    Werner, I.; Nagel, R.

    1997-11-01

    To investigate the use of stress proteins hsp60 and hsp70 as sublethal biomarkers for contaminant exposure in sediments, two infaunal (Ampelisca abdita, estuarine; Rhepoxynius abronius, marine) and one epifaunal (Hyalella azteca, freshwater) amphipod species were exposed for 24 h to solutions of the heavy metal cadmium, the pesticides diazinon and dieldrin, and the polycyclic aromatic hydrocarbon fluoranthene. All three species are routinely used in standard sediment toxicity tests. Analysis of hsp60 and hsp70 was performed using western blotting techniques with subsequent comparative quantification by densitometry. Results demonstrated compound and species-specific induction of stress protein synthesis. Whereas one member of the hsp70 protein family showed the most sensitive response to xenobiotic compounds in H. azteca, several members of the hsp60 protein family were the main proteins induced in A. abdita and R. abronius. Sensitivity of the detected stress protein response was highest in H. azteca with significant effects at concentrations 110-, 50-, >1,000-, and >1-fold lower than LC50 values for cadmium, diazinon, dieldrin, and fluoranthene, respectively. The corresponding values were >5 (cadmium), 0.7 (diazinon), >1 (dieldrin), and 2.9 (fluoranthene) for A. abdita, and >2 (cadmium), 3.1 (diazinon), > 100 (dieldrin), and >2.9 (fluoranthene) for R. abronius.

  20. Environmental drivers defining linkages among life-history traits: mechanistic insights from a semiterrestrial amphipod subjected to macroscale gradients.

    PubMed

    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. PMID:24198949

  1. Evidence for discrete solar and lunar orientation mechanisms in the beach amphipod, Talitrus saltator Montagu (Crustacea, Amphipoda)

    PubMed Central

    Ugolini, Alberto; Hoelters, Laura S.; Ciofini, Alice; Pasquali, Vittorio; Wilcockson, David C.

    2016-01-01

    Animals that use astronomical cues to orientate must make continuous adjustment to account for temporal changes in azimuth caused by Earth’s rotation. For example, the Monarch butterfly possesses a time-compensated sun compass dependent upon a circadian clock in the antennae. The amphipod Talitrus saltator possesses both a sun compass and a moon compass. We reasoned that the time-compensated compass mechanism that enables solar orientation of T. saltator is located in the antennae, as is the case for Monarch butterflies. We examined activity rhythms and orientation of sandhoppers with antennae surgically removed, or unilaterally occluded with black paint. Removing or painting the antennae did not affect daily activity rhythms or competence to orientate using the sun. However, when tested at night these animals were unable to orientate correctly to the moon. We subsequently measured circadian gene expression in the antennae and brain of T. saltator and show the clock genes period and cryptochrome 2 are rhythmically expressed in both tissues, reminiscent of other arthropods known to possess antennal clocks. Together, our behavioural and molecular data suggest that, T. saltator has anatomically discrete lunar and solar orientation apparatus; a sun compass, likely located in the brain and a moon compass in the antennae. PMID:27759059

  2. Biological testing of sediment for the Olympia Harbor Navigation Improvement Project, 1988: Geoduck, amphipod, and echinoderm bioassays

    SciTech Connect

    Ward, J.A.; Word, J.Q.; Antrim, L.D.

    1989-05-01

    The Olympia Harbor Navigation Improvement Project requires the dredging of approximately 330,000 cubic yards (cy) of sediment from the harbor entrance channel and 205,185 cy from the turning basin. Puget Sound Dredged Disposal Analysis (PSDDA) partial characterization studies were used to plan a full sediment characterization in which chemical analyses and biological testing of sediments evaluated the suitability of the dredged material for unconfined, open-water disposal. The US Army Corps of Engineers (COE), Seattle District, contracted with NOAA/NMFS, Environmental Conservation Division, to perform the chemical analysis and Microtox bioassay tests, and with the Battelle/Marine Sciences Laboratory (MSL) in Sequim to perform flow-through solid-phase bioassays utilizing juvenile (8 to 10 mm) geoduck clams, Panopea generosa, and static solid phase bioassays using the phoxocephalid amphipod, Rhepoxynius abronius, developing embryos and gametes of the purple sea urchin, Strongylocentrotus purpuratus, and the larvae of the Pacific oyster Crassostrea gigas. When the results of the biological tests were evaluated under PSDDA guidelines, it was found that all the tested sediment treatments from Olympia Harbor are suitable for unconfined open-water disposal. 14 refs., 12 figs., 3 tabs.

  3. Respiratory Response of the Deep-Sea Amphipod Stephonyx biscayensis Indicates Bathymetric Range Limitation by Temperature and Hydrostatic Pressure

    PubMed Central

    Brown, Alastair; Thatje, Sven

    2011-01-01

    Depth zonation of fauna on continental margins is well documented. Whilst increasing hydrostatic pressure with depth has long been considered a factor contributing significantly to this pattern, discussion of the relative significance of decreasing temperature with depth has continued. This study investigates the physiological tolerances of fed and starved specimens of the bathyal lysianassoid amphipod Stephonyx biscayensis at varying temperature to acute pressure exposure by measuring the rate of oxygen consumption. Acclimation to atmospheric pressure is shown to have no significant interaction with temperature and/or pressure effects. Similarly, starvation is shown to have no significant effect on the interaction of temperature and pressure. Subsequently, the effect of pressure on respiration rate is revealed to be dependent on temperature: pressure equivalent to 2000 m depth was tolerated at 1 and 3°C; pressure equivalent to 2500 m depth was tolerated at 5.5°C; at 10°C pressure equivalent to 3000 m depth was tolerated. The variation in tolerance is consistent with the natural distribution range reported for this species. There are clear implications for hypotheses relating to the observed phenomenon of a biodiversity bottleneck between 2000 and 3000 metres, and for the potential for bathymetric range shifts in response to global climate change. PMID:22174838

  4. Deformities in larvae and juvenile European lobster (Homarus gammarus) exposed to lower pH at two different temperatures

    NASA Astrophysics Data System (ADS)

    Agnalt, A.-L.; Grefsrud, E. S.; Farestveit, E.; Larsen, M.; Keulder, F.

    2013-12-01

    The ongoing warming and acidification of the world's oceans are expected to influence the marine ecosystems, including benthic marine resources. Ocean acidification may especially have an impact on calcifying organisms, and the European lobster (Homarus gammarus) is among those species at risk. A project was initiated in 2011 aiming to investigate long-term effects of ocean acidification on the early life-cycle of lobster under two temperatures. Larvae were exposed to pCO2 levels of ambient water (water intake at 90 m depth), medium 750 (pH = 7.79) and high 1200 μatm pCO2 (pH = 7.62) at temperatures 10 and 18 °C. The water parameters in ambient water did not stay stable and were very low towards the end of the experiment in the larval phase at 10 °C,with pH between 7.83 and 7.90. At 18°, pH in ambient treatment was even lower, between 7.76 and 7.83, i.e. close to medium pCO2 treatment. Long-term exposure lasted 5 months. At 18 °C the development from stage 1 to 4 lasted 14 to 16 days, as predicted under optimal water conditions. Growth was very slow at 10 °C and resulted in three larvae reaching stage 4 in high pCO2 treatment only. There were no clear effects of pCO2 treatment, on either carapace length or dry weight. However, deformities were observed in both larvae and juveniles. The proportion of larvae with deformities increased with increasing pCO2 exposure, independent of temperature. In the medium treatment about 23% were deformed, and in the high treatment about 43% were deformed. None of the larvae exposed to water of pH >7.9 developed deformities. Curled carapace was the most common deformity found in larvae raised in medium pCO2 treatment, irrespective of temperature, but damages in the tail fan occurred in addition to a bent rostrum. Curled carapace was the only deformity found in high pCO2 treatment at both temperatures. Occurrence of deformities after five months of exposure was 33 and 44% in juveniles raised in ambient and low pCO2 levels

  5. Benthic control freaks: Effects of the tubiculous amphipod Haploops nirae on the specific diversity and functional structure of benthic communities

    NASA Astrophysics Data System (ADS)

    Rigolet, Carinne; Dubois, Stanislas F.; Thiébaut, Eric

    2014-01-01

    Haploops nirae is a gregarious tubiculous amphipod which extended its habitat over thousands of hectares in shallow waters of South Brittany bays (Bay of Biscay, Atlantic) over the last decades and created uniquely large and dense tube mats. In the bay of Concarneau, we investigated the specific diversity (i.e. species richness and species composition) and the functional structure (using biological traits) of the macrofauna associated with this Haploops community as a comparison with several surrounding soft-sediment communities to determine the effect of this engineer species on ecosystem functions. We showed that the occurrence of Haploops tubes and individuals significantly modifies sediment features (e.g. change in sediment grain size, increase in C and N organic content) but also largely affect species diversity and benthic composition. The species richness was significantly higher in Haploops community but the species assemblage associated with Haploops habitat was very homogeneous compared to the neighboring habitats and unique with 33% of all species exclusively found in this community. Multivariate analysis (dbRDA) revealed that Haploops density was by far the factor explaining the variation in species composition of benthic communities. No differences in species diversity and assemblage were detected in relationship to Haploops density. A biological trait analysis performed on the whole ecosystem (Haploops included) revealed that Haploops largely dominates the functional structure of the Haploops community by its own functional traits. When performed on selected traits of the associated fauna only (Haploops excluded) the functional structure of the Haploops community was characterized by a greatly reduced proportion of small to medium long lived, sensitive to disturbance, free living or burrowing/tube-building filter-feeding species. H. nirae appears to be a bioengineer and a foundation species that largely modifies its hydro-sedimentary features

  6. Contaminants in stream sediments from seven United States metropolitan areas: part II—sediment toxicity to the amphipod Hyalella azteca and the midge Chironomus dilutus

    USGS Publications Warehouse

    Kemble, Nile E.; Hardesty, Douglas K.; Ingersoll, Christopher G.; Kunz, James L.; Sibley, Paul K.; Calhoun, Daniel L.; Gilliom, Robert J.; Kuivila, Kathryn M.; Nowell, Lisa H.; Moran, Patrick W.

    2013-01-01

    Pyrethroids are hydrophobic compounds that have been observed to accumulate in sediments (Laskowski 2002). Toxicity of pyrethroids in field-collected sediment from small urban streams (Weston et al. 2005; Holmes et al. 2008; Ding et al. 2010; Domagalski et al. 2010) or with pyrethroids spiked into sediment (Amweg et al. 2006; Hintzen et al. 2009) have been evaluated primarily in 10 day lethality tests conducted with the amphipod Hyalella azteca. However, the sublethal effects in long-term exposures to pyrethroids in sediment have not been evaluated, and the distribution of pyrethroids sediments has not typically been evaluated in wadeable streams (Gilliom et al. 2006). This article is the second in a series that describe the results of a study of the distribution and toxicity of pyrethroids and other co-occurring trace elements and organic contaminants (PCBs, PAHs, OC pesticides) in stream sediments from 7 metropolitan areas across the United States (Moran et al. 2012). The study evaluated 98 sediment samples collected from streams ranging from undeveloped to highly urban and differs from previous studies by sampling larger wadeable streams and avoiding point sources (such as storm drains) and other inflows (Gilliom et al. 2006). Part 1 of the series characterizes sediment contaminants in relation to urbanization and other factors in the 7 metropolitan study areas (Nowell et al. 2012). Part 2 (this article) evaluates relationships between sediment chemistry and sediment toxicity in 28 day whole-sediment exposures conducted with the amphipod H. azteca and in 10 day whole-sediment exposure conducted with the midge Chironomus dilutus (USEPA United States Environmental Protection Agency 2000; ASTM American Society for Testing and Materials International 2012). Toxicity end points evaluated in the amphipod and midge exposures included the effects of these field-collected sediments on survival, weight, or biomass of the test organisms.

  7. Dietary assimilation of cadmium associated with bacterial exopolymer sediment coatings by the estuarine amphipod Leptocheirus plumulosus: Effects of Cd concentration and salinity

    USGS Publications Warehouse

    Schlekat, C.E.; Decho, Alan W.; Chandler, G.T.

    1999-01-01

    Bacterial extracellular substances (also known as exopolysaccharides, or EPS) may serve as vectors for trophic transfer of metals in benthic systems because these ubiquitous sediment coatings can sorb high concentrations of toxic metals, and because many benthic invertebrates assimilate EPS sediment coatings upon ingestion. We conducted 3 sets of experiments to determine the assimilative bioavailability of EPS-associated Cd to the benthic amphipod Leptocheirus plumulosus as a function of Cd concentration and salinity. Bioavailability was measured as L. plumulosus Cd assimilation efficiency (AE) from EPS-coated silica (EPS-Si) and from uncoated silica (NC-Si) using modified pulse-chase methods with the gamma-emitting radioisotope 109Cd. Cd AE was significantly greater from NC-Si than from EPS-Si at 7.5???, but not at 2.5 or 25???. Overall, Cd AE from EPS-Si was between 15.1 and 21.5%. Because EPS-Si sorbed more Cd than NC-Si, EPS coatings magnified the amount of Cd amphipods accumulated at each salinity by up to a factor of 10. Salinity did not directly affect Cd AE from EPS-Si, but because Cd-EPS partitioning increased with decreasing salinity, amphipods accumulated more Cd from EPS at the lowest Cd-EPS incubation salinity (2.5 ???) than at higher salinities (7.5 and 25 ???). Finally, Cd concentration in EPS exhibited an inverse relationship with Cd AE at 2.5 ???, but not at 25 ???. Specifically, Cd AE was 12 times greater at 1 compared with 10 ??g Cd ??g-1 EPS. Together, these results show that estuarine benthos can accumulate Cd from EPS sediment coatings, but that the degree to which this phenomenon occurs is dependent upon seawater salinity and Cd concentration in EPS.

  8. The life cycle of Sclerocollum saudii Al-Jahdali, 2010 (Acanthocephala: Palaeacanthocephala: Rhadinorhynchidae) in amphipod and fish hosts from the Red Sea.

    PubMed

    Al-Jahdali, M O; Hassanine, R M El-Said; Touliabah, H El-S

    2015-05-01

    The rhadinorhynchid Sclerocollum saudii Al-Jahdali, 2010 was found in the intestine of its type host, Siganus rivulatus Forsskål & Niebuhr, 1775, a siganid fish permanently resident in a lagoon within the mangrove swamps found on the Egyptian coast of the Gulf of Aqaba (between 28°7'N and 28°18'N). Larval forms of this acanthocephalan (acanthors, acanthellae and cystacanths) were only found in Megaluropus agilis Hoek, 1889 (Crustacea: Gammaridae), a benthic amphipod abundant on algae and seagrasses in the lagoon. So, this life cycle of S. saudii was elucidated under semi-natural conditions: embryonated eggs of S. saudii were directly ingested by the amphipod and hatched in its intestine; the released acanthor penetrated the intestinal epithelium in 12-18 h to reach the connective tissue serosa, where it remained for about 3 days, then penetrated the intestinal wall and remained attached to its outer surface for 4 days. It then detached and dropped free in the amphipod haemocoel and transformed into an oval acanthella, growing for 16 days to reach the cystacanth stage. The cystacanth at 46 days post-infection was infective to fish (excysted in its intestine as an active juvenile). Male and female juveniles reached maturity 17 and 23 days post-infection. Recently copulated females first appeared 26 days post-infection and all females seemed to be copulated at 28 days post-infection; partially and fully gravid females first appeared 31 and 35 days post-infection. Mature males and fully gravid females started to die off naturally 31 and 43 days post-infection and were totally expelled from the fish intestine by 42 and 52 days post-infection. The cycle was completed in 89 days and is similar to other known palaeacanthocephalan life cycles, but has its own characteristics. PMID:24565051

  9. Bioaccumulation of As, Cd, Cr, Hg(II), and MeHg in killifish (Fundulus heteroclitus) from amphipod and worm prey.

    PubMed

    Dutton, Jessica; Fisher, Nicholas S

    2011-08-15

    Elevated metal levels in fish are a concern for the fish themselves, their predators, and possibly humans who consume contaminated seafood. Metal bioaccumulation models often rely on assimilation efficiencies (AEs) of ingested metals and loss rate constants after dietary exposure (k(ef)s). These models can be used to better understand processes regulating metal accumulation and can be used to make site-specific predictions of metal concentrations in animal tissues. Fish often consume a varied diet, and prey choice can influence these two parameters. We investigated the trophic transfer of As, Cd, Cr, Hg(II), and methylmercury (MeHg) from a benthic amphipod (Leptocheirus plumulosus) and an oligochaete (Lumbriculus variegatus) to killifish (Fundulus heteroclitus) using gamma-emitting radioisotopes. Except for MeHg, AEs varied between prey type. AEs were highest for MeHg (92%) and lowest for Cd (2.9-4.5%) and Cr (0.2-4%). Hg(II) showed the largest AE difference between prey type (14% amphipods, 24% worms). For Cd and Hg(II) k(ef)s were higher after consuming amphipods than consuming worms. Tissue distribution data shows that Cd and Hg(II) were mainly associated with the intestine, whereas As and MeHg were transported throughout the body. Calculated trophic transfer factors (TTFs) suggest that MeHg is likely to biomagnify at this trophic step at all ingestion rates, whereas As, Cd, Cr, and Hg(II) will not. Data collected in this study and others indicate that using one prey item to calculate AE and k(ef) could lead to an over- or underestimation of these parameters. PMID:21658746

  10. The life cycle of Sclerocollum saudii Al-Jahdali, 2010 (Acanthocephala: Palaeacanthocephala: Rhadinorhynchidae) in amphipod and fish hosts from the Red Sea.

    PubMed

    Al-Jahdali, M O; Hassanine, R M El-Said; Touliabah, H El-S

    2015-05-01

    The rhadinorhynchid Sclerocollum saudii Al-Jahdali, 2010 was found in the intestine of its type host, Siganus rivulatus Forsskål & Niebuhr, 1775, a siganid fish permanently resident in a lagoon within the mangrove swamps found on the Egyptian coast of the Gulf of Aqaba (between 28°7'N and 28°18'N). Larval forms of this acanthocephalan (acanthors, acanthellae and cystacanths) were only found in Megaluropus agilis Hoek, 1889 (Crustacea: Gammaridae), a benthic amphipod abundant on algae and seagrasses in the lagoon. So, this life cycle of S. saudii was elucidated under semi-natural conditions: embryonated eggs of S. saudii were directly ingested by the amphipod and hatched in its intestine; the released acanthor penetrated the intestinal epithelium in 12-18 h to reach the connective tissue serosa, where it remained for about 3 days, then penetrated the intestinal wall and remained attached to its outer surface for 4 days. It then detached and dropped free in the amphipod haemocoel and transformed into an oval acanthella, growing for 16 days to reach the cystacanth stage. The cystacanth at 46 days post-infection was infective to fish (excysted in its intestine as an active juvenile). Male and female juveniles reached maturity 17 and 23 days post-infection. Recently copulated females first appeared 26 days post-infection and all females seemed to be copulated at 28 days post-infection; partially and fully gravid females first appeared 31 and 35 days post-infection. Mature males and fully gravid females started to die off naturally 31 and 43 days post-infection and were totally expelled from the fish intestine by 42 and 52 days post-infection. The cycle was completed in 89 days and is similar to other known palaeacanthocephalan life cycles, but has its own characteristics.

  11. Intra-plant differences in seaweed nutritional quality and chemical defenses: Importance for the feeding behavior of the intertidal amphipod Orchestoidea tuberculata

    NASA Astrophysics Data System (ADS)

    Duarte, Cristian; Acuña, Karin; Navarro, Jorge M.; Gómez, Iván

    2011-10-01

    As a result of their morphological complexity, large macroalgae show intra-thallus variations in their nutritional composition and secondary metabolite content, which influences the trophic ecology of herbivorous invertebrates, and ultimately their fitness. In this study, we evaluated for the first time the variability in nutritional quality (protein content, carbohydrates, lipids, and total organic matter), secondary metabolites (phlorotannins), and structure (shape and toughness) between blades and stipes of the macroalgae Durvillaea Antarctica. Specifically, we looked at their effect on feeding preference, rate of consumption, absorption efficiency, and growth rate of the amphipod Orchestoidea tuberculata, one of the most abundant organisms on Chilean sandy beaches. Proteins, carbohydrates, total organic matter and phlorotannin contents were significantly higher in blades than in stipes. Preference experiments revealed that the amphipods preferred blades when fresh pieces of blades and stipes were offered at the same time. Similar results were found when artificial food (in which structures of both parts of the alga were standardized) was offered, suggesting that shape and toughness of the two different parts of the alga did not influence preference patterns of O. tuberculata. Absorption efficiency of O. tuberculata was higher on blades compared to stipes. When the amphipods were kept with each of the algal parts separately (i.e. no choice), they consumed a significantly higher amount of stipe, which suggests that O. tuberculata used food quantity to compensate for the lower nutritional quality of stipes. The higher nutritional values of blades compared to stipes appears to explain observed preference patterns by O. tuberculata. Phlorotannin content did not appear to inhibit blade consumption, suggesting that the nutritional quality of the food could be more important than chemical defense in determining food choice in O. tuberculata. Growth did not differ

  12. The recent evolutionary origin of the phenotypically novel amphipod Hyalella montezuma offers an ecological explanation for morphological stasis in a closely allied species complex.

    PubMed

    Witt, Jonathan D S; Blinn, Dean W; Hebert, Paul D N

    2003-02-01

    Numerous molecular studies have identified morphologically cryptic, freshwater invertebrate species, but have not suggested possible mechanisms for their phenotypic stasis. The amphipod crustacean genus Hyalella contains numerous morphologically cryptic species in the H. azteca complex, as well as a small number of morphologically very divergent, narrowly endemic taxa. One such taxon, Hyalella montezuma, is the sole planktonic filter-feeder within the North American amphipod fauna, and is known only from Montezuma Well, a fishless travertine spring mound in Arizona, USA. In this study, we conduct a phylogenetic analysis of mtDNA sequence data using likelihood, Bayesian and cladistic approaches to determine both the relationship of H. montezuma to the H. 'azteca' species complex, and to ascertain if its morphological and ecological differentiation have been comparatively recent. The results show that H. montezuma has a very close phylogenetic affiliation with one lineage in the H. azteca complex, indicating that its origin has been recent. We present evidence suggesting that fish predation is an important ecological factor, which constrains morphological and ecological diversification within the genus Hyalella, and that Montezuma Well has provided a relaxation on this constraint. PMID:12535091

  13. UV-tolerance and instantaneous physiological stress responses of two Antarctic amphipod species Gondogeneia antarctica and Djerboa furcipes during exposure to UV radiation.

    PubMed

    Obermüller, Birgit; Puntarulo, Susana; Abele, Doris

    2007-09-01

    We investigated the shielding against solar ultraviolet radiation and inducible damage, as well as the short-term response of whole animal metabolic rate in two Antarctic shallow water amphipod species. Light absorbance by the carapace of Gondogeneia antarctica and Djerboa furcipes was higher in the UVR (UVB+UVA) range (42.1% and 54.5% on average respectively) compared to the PAR (photosynthetically active radiation) range (38.1% and 50.1% respectively) of the solar spectrum. Bands of higher absorbance correlated with maximal absorbance ranges of sunscreening compounds indicating mycosporine-like amino acids (MAAs) and carotenoids to be innate compounds of the exoskeleton of these species. Though the antioxidant enzyme catalase was photoinhibited, protein damage products did not accumulate under experimental exposure to a daily dose of 6.84 kJ m(-2) d(-1) UVB, 66.24 kJ m(-2) d(-1) UVA and 103.14 kJ m(-2) d(-1) PAR. Animal oxygen consumption during UV-exposure was measured as an indicator of immediate behavioural and physiological stress response. UVB as well as UVA induced a response with altered and highly variable respiratory intensity. Our findings indicate that sub-lethal UVR exposure causes increased oxygen consumption in polar amphipods due to radiation avoidance, shelter seeking behaviour, and presumably also from cellular repair processes.

  14. Real-time PCR quantification of the in vitro effects of crustacean immunostimulants on gene expression in lobster (Homarus gammarus) granular haemocytes.

    PubMed

    Hauton, Chris; Hammond, John A; Smith, Valerie J

    2005-01-01

    This paper presents data from an investigation of the mode of action of five different crustacean immunostimulants presented to European lobster (Homarus gammarus) granulocytes cultured in vitro. The experiments were designed to test whether or not the immunostimulants could cause the short-term up-regulation of genes coding for immune proteins without causing the cells to degranulate. Quantitative measurements of mRNA transcript abundance were made using real-time PCR and it was first necessary to isolate the complete gene sequences coding for the proteins prophenoloxidase (proPO), beta-1,3-glucan binding protein (betaGBP) and beta-actin (beta-act) in the lobster. These sequences were used to design TaqMan primer and fluorescent probe sets. The presented data indicated that the majority of the tested immunostimulants did not induce the up-regulation of immune-related gene expression in the granulocytes in isolation. Alternative modes of action, including the in vivo up-regulation of gene expression in haemopoetic tissues, are discussed. PMID:15325521

  15. Immunolocalization of Na+,K(+)-ATPase in the organs of the branchial cavity of the European lobster Homarus gammarus (Crustacea, Decapoda).

    PubMed

    Lignot, J H; Charmantier-Daures, M; Charmantier, G

    1999-05-01

    The localization of Na+,K(+)-ATPase in epithelia of the organs of the branchial cavity of Homarus gammarus exposed to seawater and dilute seawater was examined by immunofluorescence microscopy and immunogold electron microscopy with a monoclonal antibody IgG alpha 5 raised against the avian alpha-subunit of the Na-,K(+)-ATPase. In juveniles held in seawater, fluorescent staining was observed only in the epithelial cells of epipodites. In juveniles held in dilute seawater, heavier immunoreactivity was observed in the epithelial cells of epipodites, and positive immunostaining was also observed along the inner-side epithelial layer of the branchiostegites. No fluorescent staining was observed in the gill epithelia. At the ultrastructural level, the Na+,K(+)-ATPase was localized in the basolateral infolding systems of the epipodite and inner-side branchiostegite epithelia of juveniles held in dilute seawater, mostly along the basal lamina. The expression of Na+,K(+)-ATPase therefore differs within tissues of the branchial cavity and according to the external salinity. These and previous ultrastructural observations suggest that the epipodites, and to a lesser extent the inner-side epithelium of the branchiostegites, are involved in the slight hyper-regulation displayed by lobsters at low salinity. Enhanced Na+,K(+)-ATPase activity and de novo synthesis of Na+,K(+)-ATPase within the epipodite and branchiostegite epithelia may be key points enabling lobsters to adapt to low salinity environments. PMID:10382282

  16. The effects of power station entrainment passage on three species of marine planktonic crustacean, Acartia tonsa (Copepoda), Crangon crangon (Decapoda) and Homarus gammarus (Decapoda).

    PubMed

    Bamber, Roger N; Seaby, Richard M H

    2004-05-01

    Experiments have been undertaken exposing larval common shrimp (Crangon crangon) and lobster (Homarus gammarus) and adult copepods (Acartia tonsa) to the key stresses of entrainment within power-station cooling-water systems. The apparatus has enabled the testing of mechanical, thermal, chlorine and realistic pressure effects both alone and in combination, the range of stressors spanning the standard conditions found within a temperate coastal direct-cooled power station. Mechanical stresses affected only lobster larvae, pressure changes affected only the Acartia adults. Residual chlorine caused significant mortality of Acartia and shrimp larvae, but had no effect on lobster larvae even at 1 ppm. The temperature increment significantly affected all three species, with a synergistic effect on chlorine sensitivity in the shrimp larvae, but only temperatures higher than would be experienced in a normally-operating power station affected the copepods. The majority of individuals of each species would survive passage through a power-station system under normal conditions. It is notable that, within the species tested, generalizations from the responses of one species to those of another are not valid. PMID:14749060

  17. Immunolocalization of NA(+),K(+)-ATPase in the branchial cavity during the early development of the European lobster Homarus gammarus (Crustacea, Decapoda).

    PubMed

    Lignot, J H; Charmantier, G

    2001-08-01

    We examined the ontogeny of the osmoregulatory sites of the branchial cavity in embryonic and early postembryonic stages of the European lobster Homarus gammarus through transmission electron microscopy, immunofluorescence microscopy, and immunogold electron microscopy using a monoclonal antibody IgGalpha(5) raised against the avian alpha-subunit of the Na(+),K(+)-ATPase. In mid-late embryos, Na(+),K(+)-ATPase was located along the pleurites and within the epipodite buds. In late embryos just before hatching, the enzyme was confined to the epipodite epithelia. After hatching, slight differentiations of ionocytes occured in the epipodites of larval stages. Na(+),K(+)-ATPase was also located in the ionocytes of the epipodites of larvae exposed to seawater (35.%o) and to dilute seawater (22.1 %o). After metamorphosis, the inner-side branchiostegite epithelium appeared as an additional site of enzyme location in postlarvae held in dilute seawater. Within the ionocytes, Na(+),K(+)-ATPase was mostly located along the basolateral infoldings. These observations are discussed in relation to the physiological shift from osmoconforming larvae to slightly hyper-regulating (in dilute seawater) postmetamorphic stages. The acquisition of the ability to hyper-osmoregulate probably originates from the differentiation, on the epipodites and mainly along the branchiostegites, of ionocytes that are the site of ion pumping as evidenced by the location of Na(+),K(+)-ATPase. PMID:11457929

  18. Detailed surface morphology of the 'lobster louse' copepod, Nicothoë astaci, a haematophagous gill parasite of the European lobster, Homarus gammarus.

    PubMed

    Davies, Charlotte E; Thomas, Gethin R; Maffeis, Thierry G G; Wootton, Emma C; Penny, Mark W; Rowley, Andrew F

    2014-10-01

    The ectoparasitic copepod, Nicothoë astaci (the 'lobster louse'), infests the gills of the European lobster, Homarus gammarus. There have been limited studies on this haematophagous species; therefore knowledge of this parasite is rudimentary. The current study examines the surface morphology of this parasitic copepod, detached from the host, concentrating on adaptations of the suctorial mouthpart, the oral disc. Cryo-scanning electron microscopy revealed structural adaptations that facilitate attachment of these parasites to the gill filaments of their lobster host. The aperture of the feeding channel, through which host haemolymph is drawn, is only ca. 5μm in diameter. The edge of the oral disc is lined with numerous setae, whilst the surface of the disc is covered with large numbers of small (<1μm in diameter) teeth-like structures, which presumably pierce through, and grip, the cuticle lining of the host's gill. Overall, these structures are thought to provide a 'vacuum seal' to assist in pumping of blood, via peristalsis, into the alimentary canal of the copepod host.

  19. Detailed surface morphology of the 'lobster louse' copepod, Nicothoë astaci, a haematophagous gill parasite of the European lobster, Homarus gammarus.

    PubMed

    Davies, Charlotte E; Thomas, Gethin R; Maffeis, Thierry G G; Wootton, Emma C; Penny, Mark W; Rowley, Andrew F

    2014-10-01

    The ectoparasitic copepod, Nicothoë astaci (the 'lobster louse'), infests the gills of the European lobster, Homarus gammarus. There have been limited studies on this haematophagous species; therefore knowledge of this parasite is rudimentary. The current study examines the surface morphology of this parasitic copepod, detached from the host, concentrating on adaptations of the suctorial mouthpart, the oral disc. Cryo-scanning electron microscopy revealed structural adaptations that facilitate attachment of these parasites to the gill filaments of their lobster host. The aperture of the feeding channel, through which host haemolymph is drawn, is only ca. 5μm in diameter. The edge of the oral disc is lined with numerous setae, whilst the surface of the disc is covered with large numbers of small (<1μm in diameter) teeth-like structures, which presumably pierce through, and grip, the cuticle lining of the host's gill. Overall, these structures are thought to provide a 'vacuum seal' to assist in pumping of blood, via peristalsis, into the alimentary canal of the copepod host. PMID:25196471

  20. Toxicokinetic-toxicodynamic modelling of survival of Gammarus pulex in multiple pulse exposures to propiconazole: model assumptions, calibration data requirements and predictive power.

    PubMed

    Nyman, Anna-Maija; Schirmer, Kristin; Ashauer, Roman

    2012-10-01

    Toxicokinetic-toxicodynamic (TKTD) models quantify the time-course of internal concentration, which is defined by uptake, elimination and biotransformation (TK), and the processes which lead to the toxic effects (TD). TKTD models show potential in predicting pesticide effects in fluctuating concentrations, but the data requirements and validity of underlying model assumptions are not known. We calibrated TKTD models to predict survival of Gammarus pulex in propiconazole exposure and investigated the data requirements. In order to assess the need of TK in survival models, we included or excluded simulated internal concentrations based on pre-calibrated TK. Adding TK did not improve goodness of fits. Moreover, different types of calibration data could be used to model survival, which might affect model parameterization. We used two types of data for calibration: acute toxicity (standard LC50, 4 d) or pulsed toxicity data (total length 10 d). The calibration data set influenced how well the survival in the other exposure scenario was predicted (acute to pulsed scenario or vice versa). We also tested two contrasting assumptions in ecotoxicology: stochastic death and individual tolerance distribution. Neither assumption fitted to data better than the other. We observed in 10-d toxicity experiments that pulsed treatments killed more organisms than treatments with constant concentration. All treatments received the same dose, i.e. the time-weighted average concentration was equal. We studied mode of toxic action of propiconazole and it likely acts as a baseline toxicant in G. pulex during 10-days of exposure for the endpoint survival.

  1. Toxicity and fate of two munitions constituents in spiked sediment exposures with the marine amphipod Eohaustorius estuarius.

    PubMed

    Rosen, Gunther; Lotufo, Guilherme R

    2005-11-01

    The lethal toxicity of the explosive compounds 14C-labeled 2,4,6-trinitrotoluene (TNT) and nonradiolabeled hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to the estuarine amphipod Eohaustorius estuarius was investigated in 10-d spiked sediment exposures. The 10-d median lethal concentration (LC50) was determined using the sum molar initial concentration of TNT, aminodinitrotoluenes (ADNTs), and diaminonitrotoluenes (DANTs), as determined by high-performance liquid chromatography (HPLC), and collectively referred to as HPLC-TNT*. Despite expectations of higher toxicity in sandy sediment (Yaquina Bay [YB], OR, USA) compared to relatively fine-grained sediment (San Diego Bay [SDB], CA, USA), LC50 values were similar: 159 and 125 micromol/kg, for YB and SDB sediments, respectively. When expressed as the sum of TNT and all its degradation products (14C-TNT*), LC50s were approximately two times the corresponding LC50s determined by HPLC. The HPLC-TNT* fraction likely corresponds to the most bioavailable and toxic transformation products. The concentrations of 14C-TNT* in tissues were substantially higher than those for HPLC-TNT*, suggesting that compounds other than TNT and its major aminated transformation products were prevalent. Critical body residues were similar for exposures to SDB (11.7 micromol/kg) and YB sediments (39.4 micromol/kg), despite marked differences in the nature of compounds available for uptake in the exposure media. The critical body residues for E. estuarius are lower than those reported for other aquatic invertebrates (83-172 micromol/kg). Unlike observations for TNT, RDX was only loosely associated with SDB sediment, with near complete recovery of the parent compound by chemical analysis. Exposure to RDX did not result in significant mortality even at the highest measured sediment concentration of 10,800 micromol/kg dry weight, nor tissue concentrations as high as 96 micromol/kg wet weight. The lack of RDX lethal effects in this study is

  2. Molecular taxonomy and phylogenetic affinities of two groundwater amphipods, Crangonyx islandicus and Crymostygius thingvallensis, endemic to Iceland.

    PubMed

    Kornobis, Etienne; Pálsson, Snæbjörn; Sidorov, Dmitry A; Holsinger, John R; Kristjánsson, Bjarni K

    2011-03-01

    The amphipod superfamily Crangonyctoidea is distributed exclusively in freshwater habitats worldwide and is characteristic of subterranean habitats. Two members of the family, Crangonyx islandicus and Crymostygius thingvallensis, are endemic to Iceland and were recently discovered in groundwater underneath lava fields. Crangonyx islandicus belongs to a well-known genus with representatives both in North America and in Eurasia. Crymostygius thingvallensis defines a new family, Crymostygidae. Considering the incongruences observed recently between molecular and morphological taxonomy within subterranean species, we aim to assess the taxonomical status of the two species using molecular data. Additionally, the study contributes to the phylogenetic relationships among several crangonyctoidean species and specifically among species from four genera of the family Crangonyctidae. Given the available data we consider how the two Icelandic species could have colonized Iceland, by comparing geographical origin of the species with the phylogeny. Regions of two nuclear (18S and 28S rRNA) and two mitochondrial genes (16S rRNA and COI) for 20 different species of three families of the Crangonyctoidea were sequenced. Four different methods were used to align the RNA gene sequences and phylogenetic trees were constructed using bayesian and maximum likelihood analysis. The Crangonyctidae monophyly is supported. Crangonyx islandicus appeared more closely related to species from the Nearctic region. Crymostygius thingvallensis is clearly divergent from the other species of Crangonyctoidea. Crangonyx and Synurella genera are clearly polyphyletic and showed a geographical association, being split into a Nearctic and a Palearctic group. This research confirms that the studied species of Crangonyctidae share a common ancestor, which was probably widespread in the Northern hemisphere well before the break up of Laurasia. The Icelandic species are of particular interest since Iceland

  3. Predictive distribution modeling of the sandy-beach supralittoral amphipod Atlantorchestoidea brasiliensis along a macroscale estuarine gradient

    NASA Astrophysics Data System (ADS)

    Gómez, Julio; Defeo, Omar

    2012-02-01

    Exposed marine beaches are physically rigorous habitats in which macrofaunal patterns have been well correlated with physical factors. In this context, the habitat safety hypothesis (HSH) predicts an increase in abundance of supralittoral species from dissipative to reflective conditions in microtidal oceanic beaches. However, the HSH has not been adequately tested in estuarine sandy beaches. Here, we build a predictive model based on the supralittoral talitrid amphipod Atlantorchestoidea brasiliensis that allowed us to test the HSH along a macroscale estuarine gradient. Fifteen Uruguayan sandy beaches along a salinity gradient (from 0.1 to 34.3) generated by the Río de la Plata estuary (SW Atlantic Ocean) were sampled over a two-year period. A conditional two-step procedure using a General Additive Model (GAM) was performed in order to model A. brasiliensis occurrence (1st-step) and abundance (2nd-step), based on a comprehensive set of environmental variables [salinity, water temperature, beach face slope (BFS), mean grain size, wave height and sand compaction, moisture and organic matter]. Each GAM was parameterized using generalized linear models (GLMs). An external validation procedure was used. Data were divided randomly into training (75%) and test (25%) sets. The 1st-step GAM/GLM retained 5 physical descriptors in the model (decreasing order of importance): wave height, salinity, BFS, organic matter and sand compaction. The 2nd-step GAM/GLM retained 6 physical descriptors: sand compaction, water content, salinity, wave height, water temperature and organic matter. The predictive ability of these models and the resulted combined model, as well as their external validity, was highly significant and supported the predictions of the HSH. However, the highest and lowest abundances were observed, respectively, on reflective and dissipative beaches in the outer estuary; i.e., the predictions based on the HSH did not account for the high levels of abundance

  4. Na(+) and Ca(2+) pumps in the gills, epipodites and branchiostegites of the european lobster Homarus gammarus: effects of dilute sea water.

    PubMed

    Flik, G; Haond, C

    2000-01-01

    Crude homogenates and plasma-membrane-enriched fractions were prepared from the epithelium of the gills, epipodites and branchiostegites of intermoult European lobsters Homarus gammarus, and Na(+)/K(+)-ATPase, Ca(2+)-ATPase and Na(+)/Ca(2+) exchange activities were quantified in these tissues. Lobsters were kept in sea water (salinity 35 ) or were adapted to dilute sea water (22.1 ). The lobster hyperregulates haemolymph osmolarity and Ca(2+) levels in both media. Homogenates of the podobranchs, arthrobranchs and pleurobranchs had comparable Na(+)/K(+)-ATPase specific activities, and mean activities increased significantly for all three types of gills when the animals were kept in dilute sea water. In the epipodites and branchiostegites, Na(+)/K(+)-ATPase specific activities exceeded those in the gills, and exposure to dilute sea water greatly enhanced these activities. In sea water, 80 % of the total Na(+)/K(+)-ATPase activity is associated with the gills and epipodites (each tissue containing 40 %) and 20 % with the branchiostegites; in dilute sea water, the gills contained approximately 25 %, the epipodites 40 % and the branchiostegites approximately 35 % of the total activity, indicating the relative importance of the epipodites and branchiostegites for ionic hyperregulation in dilute media. In plasma membrane vesicles isolated from the gills, epipodites and branchiostegites, Ca(2+) transport driven by ATP and by a Na(+ )gradient was demonstrated. Exposure to dilute sea water enhanced Na(+)/Ca(2+ )exchange and Ca(2+)-ATPase activities in the epipodites and branchiostegites; in the gills, however, Ca(2+) transport activities decreased. The role of these tissues and enzymes in Na(+) and Ca(2+) handling by the lobster is discussed. PMID:10607531

  5. A long-term mesocosm study on the settlement and survival of juvenile European lobster Homarus gammarus L. in four natural substrata.

    PubMed

    Linnane; Mazzoni; Mercer

    2000-06-01

    To date, the natural substratum preferences of early benthic phase (EBP) European lobsters (Homarus gammarus) remain largely unknown. This study utilised a large scale mesocosm experiment to determine if the animal favours cobble ground, similar to its American counterpart (Homarus americanus), or has other substratum preferences. Postlarvae were provided with the choice of settling on four natural substrata: sand, coralline algae, mussel shell and cobble. Over a nine month period, the number and size of juveniles on each substratum was recorded, with loss of chelipeds used as an indication of social interaction. After a 30 day period, a non-random distribution of lobsters was observed on the four substrata. Juveniles were more abundant in substrata which provided pre-existing shelter in the form of interstitial spaces, i.e. cobble and mussel shell, than in sand or coralline algae. The survival of individuals from postlarvae to 30 day old juveniles ranged from 5 to 14% with surviving benthic recruits showing a clear mode at 6-8 mm carapace length (CL) in size distribution. The density of lobsters per m(2) of cobble remained relatively constant (18/m(2)) throughout the study period while the density of juveniles on mussel shell decreased significantly (35 to 5/m(2)). The size distribution of lobsters on each substratum also varied with time. By the conclusion of the trial, lobsters found in mussel shell had a mode of 8-10 mm CL within a range of 6-14 mm CL while those in cobble had a mode of 10-12 mm CL within a range of 8-24 mm CL. Overall, the results underline the importance of shelter-providing habitat such as cobble or crevice-type substrata to EBP European lobsters. They also confirm that for a shelter-dwelling animal such as a lobster, the physical structure of the habitat is a key factor in determining both the size and number of its inhabitants. PMID:10817827

  6. Changes in immune gene expression and resistance to bacterial infection in lobster (Homarus gammarus) post-larval stage VI following acute or chronic exposure to immune stimulating compounds.

    PubMed

    Hauton, C; Brockton, V; Smith, V J

    2007-01-01

    Real-time PCR was used to measure changes in transcript abundance of genes encoding important immune proteins, namely prophenoloxidase (proPO gene), beta-1,3-glucan binding protein (betaGBP gene) and a 12.2 kDa antimicrobial peptide (amp gene) in post-larval stage VI (PLVI) juveniles of the European lobster, Homarus gammarus. Gene expression was studied in both healthy PLVI and following single or repeat exposure to a range of compounds claimed to induce immune reactivity. A single acute (3-h) exposure to any of the tested stimulants did not produce a significant increase in expression of either the proPO or betaGBP genes, measured 6h after stimulation. However, there were a small sub-group of positive responders, identified mainly from betaGBP expression, within the experimental groups stimulated with either a beta-1,3-glucan or an alginate. There was also no significant increase in the expression of any of the three genes tested 24 h after repeated weekly (3-h) exposures to a either the beta-1,3-glucan or the alginate over the longer (36-day) period. The results do show that amp is expressed at an extremely high level compared to proPO or betaGBP in healthy animals and a significant correlation was found between the expression of proPO and both betaGBP and amp, irrespective of whether or not the larvae were stimulated. None of the immune stimulated compounds improved survival of PLVI challenged with the opportunistic pathogen, Listonella anguillarum, or the lobster pathogen, Aerococcus viridans var. homari. Thus, we found no evidence to support recent claims that immunity and disease resistance can be primed or promoted within a given population of crustaceans or that these animals exhibit functional immune memory to some soluble immune elicitors. PMID:16569431

  7. The reaction of European lobster larvae (Homarus gammarus) to different quality food: effects of ontogenetic shifts and pre-feeding history.

    PubMed

    Schoo, Katherina L; Aberle, Nicole; Malzahn, Arne M; Schmalenbach, Isabel; Boersma, Maarten

    2014-02-01

    Young larval stages of many organisms represent bottlenecks in the life-history of many species. The high mortality commonly observed in, for example, decapod larvae has often been linked to poor nutrition, with most studies focussing on food quantity. Here, we focus instead on the effects of quality and have investigated its effects on the nutritional condition of lobster larvae. We established a tri-trophic food chain consisting of the cryptophyte Rhodomonas salina, the calanoid copepod Acartia tonsa and larvae of the European lobster Homarus gammarus. In a set of experiments, we manipulated the C:N:P stoichiometry of the primary producers, and accordingly those of the primary consumer. In a first experiment, R. salina was grown under N- and P-limitation and the nutrient content of the algae was manipulated by addition of the limiting nutrient to create a food quality gradient. In a second experiment, the effect on lobster larvae of long- and short-term exposure to food of varying quality during ontogenetic development was investigated. The condition of the lobster larvae was negatively affected even by subtle N- and P-nutrient limitations of the algae. Furthermore, younger lobster larvae were more vulnerable to nutrient limitation than older ones, suggesting an ontogenetic shift in the capacity of lobster larvae to cope with low quality food. The results presented here might have substantial consequences for the survival of lobster larvae in the field, as, in the light of future climate change and re-oligotrophication of the North Sea, lobster larvae might face marked changes in temperature and nutrient conditions, thus significantly altering their condition and growth. PMID:24072442

  8. Resonance raman spectroscopy and quantum chemical modeling studies of protein-astaxanthin interactions in alpha-crustacyanin (major blue carotenoprotein complex in carapace of lobster, Homarus gammarus).

    PubMed

    Weesie, R J; Merlin, J C; de Groot, H J; Britton, G; Lugtenburg, J; Jansen, F J; Cornard, J P

    1999-01-01

    Resonance Raman spectroscopy and quantum chemical calculations were used to investigate the molecular origin of the large redshift assumed by the electronic absorption spectrum of astaxanthin in alpha-crustacyanin, the major blue carotenoprotein from the carapace of the lobster, Homarus gammarus. Resonance Raman spectra of alpha-crustacyanin reconstituted with specifically 13C-labeled astaxanthins at the positions 15, 15,15', 14,14', 13,13', 12,12', or 20,20' were recorded. This approach enabled us to obtain information about the effect of the ligand-protein interactions on the geometry of the astaxanthin chromophore in the ground electronic state. The magnitude of the downshifts of the C==C stretching modes for each labeled compound indicate that the main perturbation on the central part of the polyene chain is not homogeneous. In addition, changes in the 1250-1400 cm(-1) spectral range indicate that the geometry of the astaxanthin polyene chain is moderately changed upon binding to the protein. Semiempirical quantum chemical modeling studies (Austin method 1) show that the geometry change cannot be solely responsible for the bathochromic shift from 480 to 632 nm of protein-bound astaxanthin. The calculations are consistent with a polarization mechanism that involves the protonation or another interaction with a positive ionic species of comparable magnitude with both ketofunctionalities of the astaxanthin-chromophore and support the changes observed in the resonance Raman and visible absorption spectra. The results are in good agreement with the conclusions that were drawn on the basis of a study of the charge densities in the chromophore in alpha-crustacyanin by solid-state NMR spectroscopy. From the results the dramatic bathochromic shift can be explained not only from a change in the ground electronic state conformation but also from an interaction in the excited electronic state that significantly decreases the energy of the pi-antibonding C==O orbitals and

  9. A comparison of the structure of American (Homarus americanus) and European (Homarus gammarus) lobster cuticle with particular reference to shell disease susceptibility.

    PubMed

    Davies, Charlotte E; Whitten, Miranda M A; Kim, Anita; Wootton, Emma C; Maffeis, Thierry G G; Tlusty, Michael; Vogan, Claire L; Rowley, Andrew F

    2014-03-01

    The integument of arthropods is an important first-line defence against the invasion of parasites and pathogens. Once damaged, this can be subject to colonisation by microbial agents from the surrounding environment, which in crustaceans can lead to a condition termed shell disease syndrome. This condition has been reported in several crustacean species, including crabs and lobsters. The syndrome is a progressive condition where the outer cuticle becomes pitted and eroded, and in extreme cases is compromised, leaving animals susceptible to septicaemia. This study examined the susceptibility of juvenile American (Homarus americanus) and European (Homarus gammarus) lobsters to shell disease, as a result of mechanical damage. Scanning electron microscopy was used as a method to identify differences in the cuticle structure and consequences of mechanical damage. Claw regions were aseptically punctured, whilst carapaces were abraded using sterile sandpaper, to mimic natural damage. After a period of between 10 and 12 weeks, lobsters were sacrificed, fixed and stored for later examination. The carapace and claws of juvenile American lobsters were shown to be thinner and more vulnerable to abrasion damage than their European counterparts. In addition, the number and distribution of setal pits and pore canal openings also differed between the two species of lobster. Mechanical damage resulted in the formation of shell disease lesions on the claw and carapace of both lobster species. However, American lobsters, unlike their European counterparts, had extensive bacterial colonisation on the margins of these lesions. Overall, it is concluded that the cuticle of the American lobster is more susceptible to damage and resulting microbial colonisation. This may have implications for susceptibility of both species of lobster to shell disease syndrome. PMID:24468664

  10. The reaction of European lobster larvae (Homarus gammarus) to different quality food: effects of ontogenetic shifts and pre-feeding history.

    PubMed

    Schoo, Katherina L; Aberle, Nicole; Malzahn, Arne M; Schmalenbach, Isabel; Boersma, Maarten

    2014-02-01

    Young larval stages of many organisms represent bottlenecks in the life-history of many species. The high mortality commonly observed in, for example, decapod larvae has often been linked to poor nutrition, with most studies focussing on food quantity. Here, we focus instead on the effects of quality and have investigated its effects on the nutritional condition of lobster larvae. We established a tri-trophic food chain consisting of the cryptophyte Rhodomonas salina, the calanoid copepod Acartia tonsa and larvae of the European lobster Homarus gammarus. In a set of experiments, we manipulated the C:N:P stoichiometry of the primary producers, and accordingly those of the primary consumer. In a first experiment, R. salina was grown under N- and P-limitation and the nutrient content of the algae was manipulated by addition of the limiting nutrient to create a food quality gradient. In a second experiment, the effect on lobster larvae of long- and short-term exposure to food of varying quality during ontogenetic development was investigated. The condition of the lobster larvae was negatively affected even by subtle N- and P-nutrient limitations of the algae. Furthermore, younger lobster larvae were more vulnerable to nutrient limitation than older ones, suggesting an ontogenetic shift in the capacity of lobster larvae to cope with low quality food. The results presented here might have substantial consequences for the survival of lobster larvae in the field, as, in the light of future climate change and re-oligotrophication of the North Sea, lobster larvae might face marked changes in temperature and nutrient conditions, thus significantly altering their condition and growth.

  11. A comparison of the structure of American (Homarus americanus) and European (Homarus gammarus) lobster cuticle with particular reference to shell disease susceptibility.

    PubMed

    Davies, Charlotte E; Whitten, Miranda M A; Kim, Anita; Wootton, Emma C; Maffeis, Thierry G G; Tlusty, Michael; Vogan, Claire L; Rowley, Andrew F

    2014-03-01

    The integument of arthropods is an important first-line defence against the invasion of parasites and pathogens. Once damaged, this can be subject to colonisation by microbial agents from the surrounding environment, which in crustaceans can lead to a condition termed shell disease syndrome. This condition has been reported in several crustacean species, including crabs and lobsters. The syndrome is a progressive condition where the outer cuticle becomes pitted and eroded, and in extreme cases is compromised, leaving animals susceptible to septicaemia. This study examined the susceptibility of juvenile American (Homarus americanus) and European (Homarus gammarus) lobsters to shell disease, as a result of mechanical damage. Scanning electron microscopy was used as a method to identify differences in the cuticle structure and consequences of mechanical damage. Claw regions were aseptically punctured, whilst carapaces were abraded using sterile sandpaper, to mimic natural damage. After a period of between 10 and 12 weeks, lobsters were sacrificed, fixed and stored for later examination. The carapace and claws of juvenile American lobsters were shown to be thinner and more vulnerable to abrasion damage than their European counterparts. In addition, the number and distribution of setal pits and pore canal openings also differed between the two species of lobster. Mechanical damage resulted in the formation of shell disease lesions on the claw and carapace of both lobster species. However, American lobsters, unlike their European counterparts, had extensive bacterial colonisation on the margins of these lesions. Overall, it is concluded that the cuticle of the American lobster is more susceptible to damage and resulting microbial colonisation. This may have implications for susceptibility of both species of lobster to shell disease syndrome.

  12. Strategies of Gammarus pulex L. to cope with arsenic--Results from speciation analyses by IC-ICP-MS and XAS micro-mapping.

    PubMed

    Schaller, Jörg; Koch, Iris; Caumette, Guilhem; Nearing, Michelle; Reimer, Kenneth J; Planer-Friedrich, Britta

    2015-10-15

    The invertebrate shredder Gammarus pulex L. is a key species for aquatic carbon turnover via litter decomposition and can thrive in high-arsenic (As) environments. To understand their strategies for coping with increased As concentrations while fulfilling their ecosystem functions, we analyzed the As concentration and speciation in their aquatic habitat and in leaves with heterotrophic biofilms as their natural food source. We also followed the As distribution and speciation on the cuticle and within the body of G. pulex by X-ray absorption spectroscopic imaging. Half of the total As on G. pulex was found to be associated with the cuticle but was not taken up. Removing this externally bound As yielded only arsenate in the wash solution which reflects the speciation of the surrounding aquatic phase and shows that this As does not undergo any biotransformation. The major pathway into the organism is suggested to be incorporation via food intake, but only very low amounts of As were taken up or translocated from the gut system to other tissues. In one of the main food sources, leaves, 68% arsenate and 29% monomethylarsenate were found. After ingestion into the gut system, up to 23% of the more toxic arsenite was seen, but a substantial share was methylated to dimethylarsenate (46-56%). Little arsenate and arsenite were found in the adjacent tissues. Besides 76-80% mono- and di-methylarsenate, 10-21% of the As was complexed as As(III)-S species. G. pulex plays an important role in As cycling and our results indicate that As translocation from the gut to other tissues is minimized, but a transformation to other As-species occurred.

  13. Reproductive bionomics and life history traits of three gammaridean amphipods, Cymadusa filosa Savigny, Ampithoe laxipodus Appadoo and Myers and Mallacoota schellenbergi Ledoyer from the tropical Indian Ocean (Mauritius)

    NASA Astrophysics Data System (ADS)

    Appadoo, Chandani; Myers, Alan A.

    2004-12-01

    The reproductive bionomics and life history traits of two corophiid amphipods ( Ampithoe laxipodus, Cymadusa filosa) and one melitid ( Mallacoota schellenbergi) were studied in Mauritius (Indian Ocean) for the period March 1999 to February 2000. Results on the population structure, monthly size class variations, sex ratio, female reproductive states and fecundity are presented. The study demonstrates multivoltinism and continuous reproduction in the three species. Increase in number of juveniles was observed in warmer months for C. filosa and A. laxipodus. Sexual maturity was attained at smaller sizes in warmer months in the three species. Linear relationship on body length and number of eggs in brood pouch are presented. Size-independent analysis of egg number revealed a decrease in number of eggs in cooler months. Sex ratio is male skewed in M. schellenbergi and female skewed in C. filosa and A. laxipodus. Some of the plausible explanations for the reproductive strategies adopted by these three species in a tropical system are discussed.

  14. Polychaete/amphipod ratio as an indicator of environmental impact related to offshore oil and gas production along the Norwegian continental shelf.

    PubMed

    Andrade, Hector; Renaud, Paul E

    2011-12-01

    Benthic faunal data is regularly collected worldwide to assess the ecological quality of marine environments. Recently, there has been renewed interest in developing biological indices able to identify environmental status and potential anthropogenic impacts. In this paper we evaluate the performance of a general polychaete/amphipod ratio along the Norwegian continental shelf as an environmental indicator for offshore oil and gas impacts. Two main trends are apparent: first, a contamination gradient is discernible from where production takes place compared to stations 10,000 m away. Second, the quality of the marine environment has improved over time. These results are consistent with monitoring reports employing a combination of uni- and multi-variate statistics. Thus, we consider this ratio as a relatively simple, useful and potentially cost-effective complement to other more demanding assessment techniques. Because of its strong theoretical basis, it may also be useful for detecting ecological change as a result of other activities. PMID:22000480

  15. The Panama Canal and the transoceanic dispersal of marine invertebrates: evaluation of the introduced amphipod Paracaprella pusilla Mayer, 1890 in the Pacific Ocean.

    PubMed

    Ros, Macarena; Ashton, Gail V; Lacerda, Mariana B; Carlton, James T; Vázquez-Luis, Maite; Guerra-García, José M; Ruiz, Gregory M

    2014-08-01

    Although the Panama Canal is one of the major corridors for shipping and potential dispersal of marine invaders in the tropics, little is known about the effect that the Canal has had on the distribution of marine biota. In this study, we (a) document the existence of established populations of the Western Atlantic caprellid amphipod Paracaprella pusilla, Mayer, 1890 for the first time at the Pacific entrance to the Canal, (b) review its distribution in the Pacific Ocean, and (c) evaluate possible mechanisms of introduction. The confirmed distribution of P. pusilla in the Pacific Ocean is limited to Australia, Hawaii, and Panama, despite earlier published reports from Chile and China. Laboratory experiments demonstrated intolerance of P. pusilla to freshwater, causing 100% mortality, and suggest invasion of the Pacific coast of Panama occurred through the Canal via ships' ballast water or by secondary spread via ships (ballast water or hull fouling) from another Pacific region. PMID:25060067

  16. The Panama Canal and the transoceanic dispersal of marine invertebrates: evaluation of the introduced amphipod Paracaprella pusilla Mayer, 1890 in the Pacific Ocean.

    PubMed

    Ros, Macarena; Ashton, Gail V; Lacerda, Mariana B; Carlton, James T; Vázquez-Luis, Maite; Guerra-García, José M; Ruiz, Gregory M

    2014-08-01

    Although the Panama Canal is one of the major corridors for shipping and potential dispersal of marine invaders in the tropics, little is known about the effect that the Canal has had on the distribution of marine biota. In this study, we (a) document the existence of established populations of the Western Atlantic caprellid amphipod Paracaprella pusilla, Mayer, 1890 for the first time at the Pacific entrance to the Canal, (b) review its distribution in the Pacific Ocean, and (c) evaluate possible mechanisms of introduction. The confirmed distribution of P. pusilla in the Pacific Ocean is limited to Australia, Hawaii, and Panama, despite earlier published reports from Chile and China. Laboratory experiments demonstrated intolerance of P. pusilla to freshwater, causing 100% mortality, and suggest invasion of the Pacific coast of Panama occurred through the Canal via ships' ballast water or by secondary spread via ships (ballast water or hull fouling) from another Pacific region.

  17. Morphological Evolution of Coexisting Amphipod Species Pairs from Sulfidic Caves Suggests Competitive Interactions and Character Displacement, but No Environmental Filtering and Convergence

    PubMed Central

    Fišer, Cene; Luštrik, Roman; Sarbu, Serban; Flot, Jean-François; Trontelj, Peter

    2015-01-01

    Phenotypically similar species coexisting in extreme environments like sulfidic water are subject to two opposing eco-evolutionary processes: those favoring similarity of environment-specific traits, and those promoting differences of traits related to resource use. The former group of processes includes ecological filtering and convergent or parallel evolution, the latter competitive exclusion, character displacement and divergent evolution. We used a unique eco-evolutionary study system composed of two independent pairs of coexisting amphipod species (genus Niphargus) from the sulfidic caves Movile in Romania and Frasassi in Italy to study the relative contribution and interaction of both processes. We looked at the shape of the multifunctional ventral channel as a trait ostensibly related to oxygenation and sulfide detoxification, and at body size as a resource-related trait. Phylogenetic analysis suggests that the sulfidic caves were colonized separately by ancestors of each species. Species within pairs were more dissimilar in their morphology than expected according to a null model based on regional species pool. This might indicate competitive interactions shaping the morphology of these amphipod species. Moreover, our results suggest that the shape of the ventral channel is not subject to long-term convergent selection or to the process of environmental filtering, and as such probably does not play a role in sulfide tolerance. Nevertheless, the ancestral conditions reconstructed using the comparative method tended to be more similar than null-model expectations. This shift in patterns may reflect a temporal hierarchy of eco-evolutionary processes, in which initial environmental filtering became later on superseded by character displacement or other competition-driven divergent evolutionary processes. PMID:25905793

  18. Effects of nutrient enrichment, depuration substrate, and body size on the trophic transfer of cadmium associated with microalgae to the benthic amphipod Leptocheirus plumulosus.

    PubMed

    Yu, Ri-Qing; Fleeger, John W

    2006-11-01

    Bioavailability and nutrient effects on the trophic transfer of Cd associated with microalgae to the marine benthic amphipod Leptocheirus plumulosus were investigated. Cadmium assimilation efficiency (AE) of suspension-feeding L. plumulosus significantly varied among three algal species tested (Nitzschia punctata, Thalassiosira weissflogii, and Isochrysis galbana). Depuration substrate greatly influenced Cd AE for L. plumulosus (AE was much higher for nonburrowed amphipods), probably because sediment burrowing allowed L. plumulosus to feed as a surface deposit feeder. The L. plumulosus body size, ranging from 0.5 to 2.0 mm, did not affect Cd AE. Nitrate enrichment from 0 to 180 microM in algal culture significantly increased Cd AE from 9.4 to 18.8% for T. weissflogii, from 10.0 to 27.3% for N. punctata, and from 10.0 to 16.2% for I. galbana; nitrate enrichment from 0 to 60 microM did not influence Cd AE in any algal species tested. Physiological turnover rate constants of Cd in L. plumulosus ranged from 0.016 to 0.025/h for the three species and were independent of nitrate addition. Nitrate enrichment strongly enhanced Cd distribution in algal cytoplasm. Phosphate enrichment (0-7.5 miroM) did not significantly affect Cd AEs in L. plumulosus. Overall, a significant linear relationship was observed between the Cd AE of L. plumulosus and the fraction of Cd available in algal cytoplasm. Our work suggests that eutrophication by nitrate enrichment has the potential to enhance the trophic transfer of Cd from microalgae to suspension-feeding benthic invertebrates. PMID:17089733

  19. Temperature-dependent toxicities of nano zinc oxide to marine diatom, amphipod and fish in relation to its aggregation size and ion dissolution.

    PubMed

    Wong, Stella W Y; Leung, Kenneth M Y

    2014-08-01

    This study, for the first time, concurrently investigated the influence of seawater temperature, exposure concentration and time on the aggregation size and ion dissolution of nano zinc oxides (nZnO) in seawater, and the interacting effect of temperature and waterborne exposure of nZnO to the marine diatom Skeletonema costatum, amphipod Melita longidactyla and fish Oryzias melastigma, respectively. Our results showed that aggregate size was jointly affected by seawater temperature, nZnO concentration and exposure time. Among the three factors, the concentration of nZnO was the most important and followed by exposure time, whereas temperature was less important as reflected by their F values in the three-way analysis of variance (concentration: F3, 300 = 247.305; time: F2, 300 = 20.923 and temperature: F4, 300 = 4.107; All p values <0.001). The aggregate size generally increased with increasing nZnO concentration and exposure time. The release of Zn ions from nZnO was significantly influenced by seawater temperature and exposure time; the ion dissolution rate generally increased with decreasing temperature and increasing exposure time. Growth inhibition of diatoms increased with increasing temperature, while temperature and nZnO had an interactional effect on their photosynthesis. For the amphipod, mortality was positively correlated with temperature. Fish larvae growth rate was only affected by temperature but not nZnO, while the two factors interactively modulated the expression of heat shock and metallothionein proteins. Evidently, temperature can influence aggregate size and ion dissolution and thus toxicity of nZnO to the marine organisms in a species-specific manner. PMID:24219175

  20. Morphological evolution of coexisting amphipod species pairs from sulfidic caves suggests competitive interactions and character displacement, but no environmental filtering and convergence.

    PubMed

    Fišer, Cene; Luštrik, Roman; Sarbu, Serban; Flot, Jean-François; Trontelj, Peter

    2015-01-01

    Phenotypically similar species coexisting in extreme environments like sulfidic water are subject to two opposing eco-evolutionary processes: those favoring similarity of environment-specific traits, and those promoting differences of traits related to resource use. The former group of processes includes ecological filtering and convergent or parallel evolution, the latter competitive exclusion, character displacement and divergent evolution. We used a unique eco-evolutionary study system composed of two independent pairs of coexisting amphipod species (genus Niphargus) from the sulfidic caves Movile in Romania and Frasassi in Italy to study the relative contribution and interaction of both processes. We looked at the shape of the multifunctional ventral channel as a trait ostensibly related to oxygenation and sulfide detoxification, and at body size as a resource-related trait. Phylogenetic analysis suggests that the sulfidic caves were colonized separately by ancestors of each species. Species within pairs were more dissimilar in their morphology than expected according to a null model based on regional species pool. This might indicate competitive interactions shaping the morphology of these amphipod species. Moreover, our results suggest that the shape of the ventral channel is not subject to long-term convergent selection or to the process of environmental filtering, and as such probably does not play a role in sulfide tolerance. Nevertheless, the ancestral conditions reconstructed using the comparative method tended to be more similar than null-model expectations. This shift in patterns may reflect a temporal hierarchy of eco-evolutionary processes, in which initial environmental filtering became later on superseded by character displacement or other competition-driven divergent evolutionary processes.

  1. Description of Pseudingolfiella possessionis n. sp. (Crustacea, Amphipoda) from sub-Antarctic Île de La Possession, Crozet archipelago: the second freshwater amphipod known from the Antarctic biome, a human introduction of Gondwanan ancestry?

    PubMed

    Smet, Willem H De

    2015-01-01

    A new species of freshwater amphipod, Pseudingolfiella possessionis n. sp. (Senticaudata, Pseudingolfiellidae), is described from the submerged moss vegetation of small brooklets at sub-Antarctic Île de La Possession, Crozet archipelago. It constitutes the second freshwater amphipod species known for the sub-Antarctic and Antarctic region, and the fourth member of the genus. The main characters distinguishing it from all congeners are: the spine on the posterior margin of the dactylus, incisor and lamina mobilis of mandible each with 5 teeth, the setation of the maxilliped, the vestigial second article of pleopod 3 in the female, the undulate and laterally notched posterolateral margin of the external ramus of uropods 1 and 2 in the male, the spinulate dorsomedian projection of the telson.

  2. Morphologically Cryptic Amphipod Species Are "Ecological Clones" at Regional but Not at Local Scale: A Case Study of Four Niphargus Species.

    PubMed

    Fišer, Žiga; Altermatt, Florian; Zakšek, Valerija; Knapič, Tea; Fišer, Cene

    2015-01-01

    Recent studies indicate that morphologically cryptic species may be ecologically more different than would be predicted from their morphological similarity and phylogenetic relatedness. However, in biodiversity research it often remains unclear whether cryptic species should be treated as ecologically equivalent, or whether detected differences have ecological significance. In this study, we assessed the ecological equivalence of four morphologically cryptic species of the amphipod genus Niphargus. All species live in a small, isolated area on the Istrian Peninsula in the NW Balkans. The distributional ranges of the species are partially overlapping and all species are living in springs. We reconstructed their ecological niches using morphological traits related to feeding, bioclimatic niche envelope and species' preference for epi-hypogean habitats. The ecological meaning of differences in niches was evaluated using distributional data and co-occurrence frequencies. We show that the species comprise two pairs of sister species. All species differ from each other and the degree of differentiation is not related to phylogenetic relatedness. Moreover, low co-occurrence frequencies in sympatric zones imply present or past interspecific competition. This pattern suggests that species are not differentiated enough to reduce interspecific competition, nor ecologically equivalent to co-exist via neutral dynamics. We tentatively conclude that the question of ecological equivalence relates to the scale of the study: at a fine scale, species' differences may influence dynamics in a local community, whereas at the regional level these species likely play roughly similar ecological roles.

  3. Morphologically Cryptic Amphipod Species Are “Ecological Clones” at Regional but Not at Local Scale: A Case Study of Four Niphargus Species

    PubMed Central

    Fišer, Žiga; Altermatt, Florian; Zakšek, Valerija; Knapič, Tea; Fišer, Cene

    2015-01-01

    Recent studies indicate that morphologically cryptic species may be ecologically more different than would be predicted from their morphological similarity and phylogenetic relatedness. However, in biodiversity research it often remains unclear whether cryptic species should be treated as ecologically equivalent, or whether detected differences have ecological significance. In this study, we assessed the ecological equivalence of four morphologically cryptic species of the amphipod genus Niphargus. All species live in a small, isolated area on the Istrian Peninsula in the NW Balkans. The distributional ranges of the species are partially overlapping and all species are living in springs. We reconstructed their ecological niches using morphological traits related to feeding, bioclimatic niche envelope and species’ preference for epi-hypogean habitats. The ecological meaning of differences in niches was evaluated using distributional data and co-occurrence frequencies. We show that the species comprise two pairs of sister species. All species differ from each other and the degree of differentiation is not related to phylogenetic relatedness. Moreover, low co-occurrence frequencies in sympatric zones imply present or past interspecific competition. This pattern suggests that species are not differentiated enough to reduce interspecific competition, nor ecologically equivalent to co-exist via neutral dynamics. We tentatively conclude that the question of ecological equivalence relates to the scale of the study: at a fine scale, species’ differences may influence dynamics in a local community, whereas at the regional level these species likely play roughly similar ecological roles. PMID:26226375

  4. A two-step experimental design for a sediment bioassay using growth of the amphipod Hyalella azteca for the test end point

    USGS Publications Warehouse

    Kubitz, Jody A.; Besser, John M.; Giesy, John P.

    1996-01-01

    We designed a sediment bioassay using 25% growth inhibition of Hyalella azteca as the end point.Hyalella azteca exhibits size-specific fecundity, so growth is a surrogate of reproductive production. We investigated density effects on growth to address whether crowding could affect test interpretation; amphipods in 14,000/m2 exposures were 16 to 20% smaller than those at 7,000/m2. Using power analysis, we found that 20 to 25 samples are required to determine significance when α = 0.10 and 1 − β = 0.90. To minimize the need for laboratory resources, we designed a two-step (screening and confirmatory) bioassay, which we tested with field-collected sediments. The screening bioassay compared 11 sediments to a reference. Three sediments were “toxic” (significant growth inhibition when 1 − β = 0.66 and n = 5), five sediments were “nontoxic” (>90% of reference), and three sediments were “possibly toxic” (growth inhibition was insignificant). In the confirmatory bioassay, three possibly toxic and two nontoxic samples were reevaluated. Two were toxic (1 − β = 0.91 and n = 20), and the remaining four samples were nontoxic. In summary, five sediments were toxic and six sediments were nontoxic. The two-step analysis used minimal laboratory resources but maximized statistical power, where needed, to discriminate growth effects.

  5. Distribution and respiration of the high-latitude pelagic amphipod Themisto gaudichaudi in the Benguela Current in relation to upwelling intensity

    NASA Astrophysics Data System (ADS)

    Auel, Holger; Ekau, Werner

    2009-12-01

    The cold and highly productive waters of coastal upwelling areas provide habitats for marine species usually occurring at higher latitudes and allow those species to extend their distribution ranges towards the equator into regions otherwise characterised by warm and oligotrophic sub-tropical waters. The pelagic hyperiid amphipod Themisto gaudichaudi has a circum-Antarctic epipelagic distribution pattern generally south of 35°S and plays an important role in Antarctic food webs as effective link from zooplankton secondary production to higher trophic levels including seabirds and marine mammals. In the cold and productive waters of the Benguela Current coastal upwelling system, the distribution range of the species extents far northward into the subtropics. The present study focuses on the distribution of T. gaudichaudi at the northernmost limit of its range in the Benguela upwelling system in relation to upwelling intensity and hydrographic conditions (sea surface temperature) based on time-series data from 2002 to 2008. Moreover, field data on life-history traits and respiration rates in relation to water temperature are combined to elucidate the environmental and physiological factors limiting the distribution range. Compared to Themisto populations from higher latitudes, the relatively higher water temperatures in the coastal upwelling region lead to higher respiration rates, faster growth, earlier sexual maturity and smaller body size.

  6. Relative sensitivity of an amphipod Hyalella azteca, a midge Chironomus dilutus, and a unionid mussel Lampsilis siliquoidea to a toxic sediment

    USGS Publications Warehouse

    Ingersoll, Christopher G.; Kunz, James L.; Hughes, James P.; Wang, Ning; Ireland, D. Scott; Mount, Dave R.; Hockett, Russ J; Valenti, Ted W

    2015-01-01

    The objective of the present study was to evaluate the relative sensitivity of test organisms in exposures to dilutions of a highly toxic sediment contaminated with metals and organic compounds. One dilution series was prepared using control sand (low total organic carbon [TOC; <0.1%, low binding capacity for contaminants]) and a second dilution series was prepared using control sediment from West Bearskin Lake, Minnesota, USA (high TOC [~10% TOC, higher binding capacity for contaminants]). Test organisms included an amphipod (Hyalella azteca; 10-d and 28-d exposures), a midge (Chironomus dilutus; 20-d and 48-d exposures started with <1-h-old larvae, and 13-d and 48-d exposures started with 7-d-old larvae), and a unionid mussel (Lampsilis siliquoidea; 28-d exposures). Relative species sensitivitydepended on the toxicity endpoint and the diluent. All 3 species were more sensitive in sand dilutions than in West Bearskin Lake sediment dilutions. The <1-h-old C. dilutus were more sensitive than 7-d-old C. dilutus, but replicate variability was high in exposures started with the younger midge larvae. Larval biomass and adult emergence endpoints of C. dilutus exhibited a similar sensitivity. Survival, weight, and biomass of H. azteca were more sensitive endpoints in 28-d exposures than in 10-d exposures. Weight and biomass of L. siliquoidea were sensitive endpoints in both sand and West Bearskin Lake sediment dilutions. Metals, ammonia, oil, and other organic contaminants may have contributed to the observed toxicity.

  7. Vicariance and dispersal effects on phylogeographic structure and speciation in a widespread estuarine invertebrate.

    PubMed

    Kelly, David W; MacIsaac, Hugh J; Heath, Daniel D

    2006-02-01

    Vicariance and dispersal can strongly influence population genetic structure and allopatric speciation, but their importance in the origin of marine biodiversity is unresolved. In transitional estuarine environments, habitat discreteness and dispersal barriers could enhance divergence and provide insight to evolutionary mechanisms underlying marine and freshwater biodiversity. We examined this by assessing phylogeographic structure in the widespread amphipod Gammarus tigrinus across 13 estuaries spanning its northwest Atlantic range from Quebec to Florida. Mitochondrial cytochrome c oxidase I and nuclear internal transcribed spacer 1 phylogenies supported deep genetic structure consistent with Pliocene separation and cryptic northern and southern species. This break occurred across the Virginian-Carolinian coastal biogeographic zone, where an oceanographic discontinuity may restrict gene flow. Ten estuarine populations of the northern species occurred in four distinct clades, supportive of Pleistocene separation. Glaciation effects on genetic structure of estuarine populations are largely unknown, but analysis of molecular variance (AMOVA) supported a phylogeographic break among clades in formerly glaciated versus nonglaciated areas across Cape Cod, Massachusetts. This finding was concordant with patterns in other coastal species, though there was no significant relationship between latitude and genetic diversity. This supports Pleistocene vicariance events and divergence of clades in different northern glacial refugia. AMOVA results and private haplotypes in most populations support an allopatric distribution across estuaries. Clade mixture zones are consistent with historical colonization and human-mediated transfer. An isolation-by-distance model of divergence was detected after we excluded a suspected invasive haplotype in the St. Lawrence estuary. The occurrence of cryptic species and divergent population structure support limited dispersal, dispersed habitat

  8. Contrasting patterns in genetic diversity following multiple invasions of fresh and brackish waters.

    PubMed

    Kelly, David W; Muirhead, James R; Heath, Daniel D; Macisaac, Hugh J

    2006-10-01

    Biological invasions may combine the genetic effects of population bottlenecks and selection and thus provide valuable insight into the role of such processes during novel environmental colonizations. However, these processes are also influenced by multiple invasions, the number of individuals introduced and the degree of similarity between source and receiving habitats. The amphipod Gammarus tigrinus provides a useful model to assess these factors, as its invasion history has involved major environmental transitions. This species is native to the northwest Atlantic Ocean, although it invaded both brackish and freshwater habitats in the British Isles after introduction more than 65 years ago. It has also spread to similar habitats in Western Europe and, most recently, to Eastern Europe, the Baltic Sea, and the Laurentian Great Lakes. To examine sources of invasion and patterns of genetic change, we sampled populations from 13 native estuaries and 19 invaded sites and sequenced 542 bp of the mitochondrial COI gene. Strong native phylogeographical structure allowed us to unambiguously identify three allopatrically evolved clades (2.3-3.1% divergent) in invading populations, indicative of multiple introductions. The most divergent clades occurred in the British Isles and mainland Europe and were sourced from the St Lawrence and Chesapeake/Delaware Bay estuaries. A third clade was found in the Great Lakes and sourced to the Hudson River estuary. Despite extensive sampling, G. tigrinus did not occur in freshwater at putative source sites. Some European populations showed reduced genetic diversity consistent with bottlenecks, although selection effects cannot be excluded. The habitat distribution of clades in Europe was congruent with the known invasion history of secondary spread from the British Isles. Differences in salinity tolerance among lineages were suggested by patterns of habitat colonization by different native COI clades. Populations consisting of admixtures

  9. Shifts in the diets of slimy sculpin (Cottus cognatus) and lake whitefish (Coregonus clupeaformis) in Lake Ontario following the collapse of the burrowing amphipod Diporeia

    USGS Publications Warehouse

    Owens, Randall W.; Dittman, Dawn E.

    2003-01-01

    In Lake Ontario, the diets of slimy sculpin Cottus cognatus and lake whitefish Coregonus clupeaformis shifted from a diet dominated by the burrowing amphipod, Diporeia, and to a lesser extent, Mysis, to a more diverse diet, after Diporeia collapsed, to one dominated by Mysis and prey that were formerly less important or uncommon such as Chironomidae, Oligochaeta, and Ostracoda. Additionally, lake whitefish still preyed on native mollusks like Sphaeriidae and Gastropoda, but also preyed on exotic mollusks, Dreissena spp., which are swallowed intact and subsequently crushed in its muscular stomach. Whether Diporeia was abundant (1992) or scarce (1999), selection indices for Diporeia by slimy sculpins was positive, suggesting that Diporeia was a preferred prey. Unlike lake whitefish, slimy sculpins avoided Dreissena; therefore, energy diverted to Dreissena production was a real loss for slimy sculpins. The shifts in the diet of these benthic fishes corresponded with drastic changes in the benthic community between 1992 and 1999. The collapse of Diporeia, formerly the most abundant macroinvertebrate in the benthic community, along with sharp declines in the abundance of Oligochaeta and Sphaeriidae, coincided with the establishment and rapid expansion of Dreissena bugensis, the quagga mussel, and to a lesser degree Dreissena polymorpha, the zebra mussel. It appears that the Diporeia population first collapsed at depths >70 m in southeastern Lake Ontario by autumn 1992, at shallower depths in the eastern Lake Ontario by 1995, and along the entire south shore line at depths 100 m by 1999. In response to the disappearance of Diporeia, populations of two native benthivores, slimy sculpin and lake whitefish, collapsed in eastern Lake Ontario, perhaps due in part to starvation, because Diporeia was their principal prey. Presently, alternative food resources do not appear sufficient to sustain these two benthivores at their former levels of abundance. We do not expect slimy

  10. A comparison of equilibrium partitioning and critical body residue approaches for predicting toxicity of sediment-associated fluoranthene to freshwater amphipods

    SciTech Connect

    Driscoll, S.K.; Landrum, P.F.

    1997-10-01

    Equilibrium partitioning (EqP) theory predicts that the effects of organic compounds in sediments can be assessed by comparison of organic carbon-normalized sediment concentrations and estimated pore-water concentrations to effects determined in water-only exposures. A complementary approach, the critical body residue (CBR) theory, examines actual body burdens in relation to toxic effects. Critical body residue theory predicts that the narcotic effects of nonpolar compounds should be essentially constant for similar organisms, and narcosis should be observed at body burdens of 2 to 8 {micro}mol/g tissue. This study compares these two approaches for predicting toxicity of the polycyclic aromatic hydrocarbon (PAH) fluoranthene. The freshwater amphipods Hyalella azteca and Diporeia spp. were exposed for up to 30 d to sediment spiked with radiolabeled fluoranthene at concentrations of 0.1 (trace) to 3.940 nmol/g dry weight (= 346 {micro}mol/g organic carbon). Mean survival of Diporeia was generally high (>70%) and not significantly different from that of control animals. This result agrees with EqP predictions, because little mortality was observed for Diporeia in 10-d water-only exposures to fluoranthene in previous studies. After 10-d exposures, mortality of H. azteca was not significantly different from that of controls, even though measured interstitial water concentrations exceeded the previously determined 10-d water-only median lethal concentration (LC50). Equilibrium partitioning overpredicted fluoranthene sediment toxicity in this species. More mortality was observed for H. azteca at later time points, and a 16-d LC50 of 3.550 nmol/g dry weight sediment (291 {micro}mol/g organic carbon) was determined. A body burden of 1.10 {micro}mol fluoranthene-equivalents/g wet weight in H. azteca was associated with 50% mortality after 16-d exposures. Body burdens as high as 5.9 {micro}mol/g wet weight resulted in little mortality in Diporeia.

  11. Genetic and Morphological Divergences in the Cosmopolitan Deep-Sea Amphipod Eurythenes gryllus Reveal a Diverse Abyss and a Bipolar Species

    PubMed Central

    Havermans, Charlotte; Sonet, Gontran; d’Udekem d’Acoz, Cédric; Nagy, Zoltán T.; Martin, Patrick; Brix, Saskia; Riehl, Torben; Agrawal, Shobhit; Held, Christoph

    2013-01-01

    Eurythenes gryllus is one of the most widespread amphipod species, occurring in every ocean with a depth range covering the bathyal, abyssal and hadal zones. Previous studies, however, indicated the existence of several genetically and morphologically divergent lineages, questioning the assumption of its cosmopolitan and eurybathic distribution. For the first time, its genetic diversity was explored at the global scale (Arctic, Atlantic, Pacific and Southern oceans) by analyzing nuclear (28S rDNA) and mitochondrial (COI, 16S rDNA) sequence data using various species delimitation methods in a phylogeographic context. Nine putative species-level clades were identified within E. gryllus. A clear distinction was observed between samples collected at bathyal versus abyssal depths, with a genetic break occurring around 3,000 m. Two bathyal and two abyssal lineages showed a widespread distribution, while five other abyssal lineages each seemed to be restricted to a single ocean basin. The observed higher diversity in the abyss compared to the bathyal zone stands in contrast to the depth-differentiation hypothesis. Our results indicate that, despite the more uniform environment of the abyss and its presumed lack of obvious isolating barriers, abyssal populations might be more likely to show population differentiation and undergo speciation events than previously assumed. Potential factors influencing species’ origins and distributions, such as hydrostatic pressure, are discussed. In addition, morphological findings coincided with the molecular clades. Of all specimens available for examination, those of the bipolar bathyal clade seemed the most similar to the ‘true’ E. gryllus. We present the first molecular evidence for a bipolar distribution in a macro-benthic deep-sea organism. PMID:24086322

  12. Substrate dependent talitrid amphipods from fragmented beaches on the north coast of Crete (Crustacea, Amphipoda, Talitridae), including a redefinition of the genus Orchestia and descriptions of Orchestia xylino sp. nov. and Cryptorchestia gen. nov.

    PubMed

    Lowry, J K; Fanini, Lucia

    2013-01-01

    Four species of talitrid amphipods (Orchestia montagui Audouin, 1826, Orchestia stephenseni Cecchini, 1928, Orchestia xylino sp. nov. and Talitrus saltator (Montagu, 1808)) are reported from a set of fragmented pocket beaches to the east of Heraklion on the north coast of Crete. Aside from a previous record of O. stephenseni these are the first records of talitrid amphipods from the island of Crete. 2) Along a coastal segment of only 4.36 km, characterised by habitat fragmentation and substrate patchiness, a clear correlation between talitrid species and beach type is indicated. Talitrus saltator occurs only on sandy beaches. Orchestia montagui and O. xylino occur on banquette beaches and O. montagui, O. stephenseni and O. xylino occur on mixed sand/gravel and cobble beaches. 3) The genus Orchestia is redefined and confined to 15 marine supralittoral species from eastern North America, islands in the North-eastern Atlantic, and western-Europe, including the Baltic and the Mediterranean Seas plus a perplexing group in New Zealand. 4) The new genus Cryptorchestia is described, based on nine terrestrial species previously included in the genus Orchestia and occurring in western Europe, the Mediterranean Sea and the Azores and Canary islands in the North-eastern Atlantic. 5) The new species Orchestia xylino sp. nov. is described. 6) An extensive bibliography for the species in this study is provided.

  13. Fusiforma themisticola n. gen., n. sp., a new genus and species of apostome ciliate infecting the hyperiid amphipod Themisto libellula in the Canadian Beaufort Sea (Arctic Ocean), and establishment of the Pseudocolliniidae (Ciliophora, Apostomatia).

    PubMed

    Chantangsi, Chitchai; Lynn, Denis H; Rueckert, Sonja; Prokopowicz, Anna J; Panha, Somsak; Leander, Brian S

    2013-11-01

    A novel parasitic ciliate Fusiforma themisticola n. gen., n. sp. was discovered infecting 4.4% of the hyperiid amphipod Themisto libellula. Ciliates were isolated from a formaldehyde-fixed whole amphipod and the DNA was extracted for amplification of the small subunit (SSU) rRNA gene. Sequence and phylogenetic analyses showed unambiguously that this ciliate is an apostome and about 2% divergent from the krill-infesting apostome species assigned to the genus Pseudocollinia. Protargol silver impregnation showed a highly unusual infraciliature for an apostome. There are typically 8 (6-9) bipolar somatic kineties covering the banana-shaped body. The anterior end of the oral cavity begins about 1/3 of the body length from the anterior end and is composed of an inpocketing that is lined on its anterior and left wall with an oral field of densely packed ciliated kinetosomes. Stomatogenesis begins with some dedifferentiation of the parental oral field and elongation of its paroral and oral kineties. A new oral field develops midventrally and the paroral and oral kineties break to form the oral apparatus of the opisthe, which completes development by additional kinetosomal proliferation and migration of the paroral. This morphology is novel among apostomes and justifies the establishment of a new genus and species.

  14. Cloning of a crustin-like, single whey-acidic-domain, antibacterial peptide from the haemocytes of the European lobster, Homarus gammarus, and its response to infection with bacteria.

    PubMed

    Hauton, C; Brockton, V; Smith, V J

    2006-03-01

    Degenerate PCR was used to isolate a 221-base pair nucleotide sequence of a new crustin-like antibacterial peptide from the haemocytes of the European lobster, Homarus gammarus. Rapid amplification of cDNA ends was used to extend the sequence to determine the complete open reading frame and un-translated regions. The inferred amino acid sequence of this peptide was found to be similar to crustin-like peptides isolated for several species of shrimp as well as the shore crab, Carcinus maenas. The sequence also contains a single-whey-acidic protein (WAP) domain, similar to novel antibacterial single-whey-acidic domain (SWD) peptides that have been recently described in the tiger shrimp, Penaeus monodon, and the Pacific white shrimp, Litopenaeus vannamei. Real-time PCR was used to analyse the expression of the gene coding for this peptide. The gene is up regulated after inoculation with the Gram-positive lobster pathogen Aerococcus viridans var. homari but down regulated after inoculation with the Gram-negative bacteria Listonella anguillarum. Phylogenetic analysis of this new peptide shows that it is most related to other antimicrobial crustin peptides and that the crustins are only distantly related to the antibacterial SWD peptides recently described. PMID:16144710

  15. Zur Ökophysiologie, Sexualität und Populationsgenetik litoraler Gammaridea — ein Überblick

    NASA Astrophysics Data System (ADS)

    Bulnheim, H.-P.

    1991-09-01

    Comparative investigations on the physiological capacities in the euryhaline amphipods Gammarus locusta, G. oceanicus, G. salinus, G. zaddachi and G. duebeni were reviewed. In order to assess the adaptations of these species to the abiotic conditions of their environment, the following criteria were examined: oxygen consumption in relation to ambient salinity and temperature levels, respiratory responses following osmotic stress, resistance capacities to oxygen deficiency, resistance to aerial exposure and the simultaneous presence of hydrogen sulphide. Covering the range from marine to typically brackish-water inhabitants, the 5 species show adaptive responses in the above-mentioned order. Respiration is less intensely modified by external factors, and oxygen consumption decreases. Accompanied by faster rates of acclimation to new steady states of performance, resistance capacities increase. The significance of the findings obtained is discussed in relation to the environmental requirements of the amphipods considered. Based on breeding experiments, the sex-determining systems reported thus far in Gammarus species are outlined. As demonstrated in G. duebeni, a more or less pronounced influence of external factors such as photoperiod may become effective. A preponderance of males was noted when offspring were raised under long-day photoperiods, whereas females prevailed under short-day conditions. In terms of the critical daylength, the light per day was estimated as being between 13 and 14 h (Elbe estuary population). Feminizing microporidians ( Octosporea effeminans, Thelohania herediteria), which are transovarially transmitted, can interfere with the system of sex determination and sex differentiation of the host. As reflected in various G. duebeni populations, they cause a maternally transferred sex-ratio condition by the production of all-female broods, thereby mimicking extrachromosomal inheritance. An increase of the salinity level to 25 30‰ results in a

  16. 13C Magic angle spinning NMR analysis and quantum chemical modeling of the bathochromic shift of astaxanthin in alpha-crustacyanin, the blue carotenoprotein complex in the carapace of the lobster Homarus gammarus.

    PubMed

    Weesie, R J; Jansen, F J; Merlin, J C; Lugtenburg, J; Britton, G; de Groot, H J

    1997-06-17

    Selective isotope enrichment, 13C magic angle spinning (MAS) NMR, and semiempirical quantum chemical modeling, have been used to analyze ligand-protein interactions associated with the bathochromic shift of astaxanthin in alpha-crustacyanin, the blue carotenoprotein complex from the carapace of the lobster Homarus gammarus. Spectra of alpha-crustacyanin were obtained after reconstitution with astaxanthins labeled with 13C at positions 4,4', 12,12', 13,13', or 20,20'. The data reveal substantial downfield shifts of 4.9 and 7.0 ppm at positions 12 and 12' in the complex, respectively. In contrast, at the 13 and 13' positions, small upfield shifts of 1.9 ppm were observed upon binding to the protein. These data are in line with previously obtained results for positions 14,14' (3.9 and 6.8 ppm downfield) and 15,15' (0.6 ppm upfield) and confirm the unequal perturbation of both halves after binding of the chromophore. However, these results also show that the main perturbation is of symmetrical origin, since the chemical shift differences exhibit a similar pattern in both halves of the astaxanthin molecule. A small downfield shift of 2.4 ppm was detected for the 4 and 4' positions. Finally, the 20,20' methyl groups are shifted 0.4 ppm upfield by the protein. The full data set provides convincing evidence that charge polarization is of importance for the bathochromic shift. The NMR shifts are compared with calculated charge densities for astaxanthin subjected to variations in protonation states of the ring-functional groups, as models of ligand-protein interactions. Taking into account the color shift and other available optical data, the current model for the mechanisms of interaction with the protein was refined. The results point toward a mechanism in which the astaxanthin is charged and subject to strong electrostatic polarizations originating from both keto groups, most likely a double protonation. PMID:9200677

  17. Demonstrating That Habitat Structure Facilitates Coexistence of Prey & Predator: A Laboratory Investigation Using Goldfish & Invertebrates.

    ERIC Educational Resources Information Center

    Stewart, Timothy W.; Embrey, Tracey R.

    2003-01-01

    Presents a laboratory investigation to demonstrate that habitat structure promotes increased organism abundance and species diversity by reducing predator effects on prey abundance. Investigates the effects of goldfish (Carassius auratus) predators on Gammarus sp. (an amphipod) and Daphnia magna (a cladoceran) prey in the absence and presence of a…

  18. Microsporidian parasites feminise hosts without paramyxean co-infection: support for convergent evolution of parasitic feminisation.

    PubMed

    Ironside, Joseph Edward; Alexander, Jenna

    2015-05-01

    Feminisation of amphipod crustaceans is associated with the presence of at least three microsporidian parasites and one paramyxean parasite, suggesting that the ability to feminise has evolved multiple times in parasites of amphipods. Co-infection by a paramyxean with one of the putative microsporidian feminisers, Dictyocoela duebenum, has inspired the alternative hypothesis that all feminisation of amphipods is caused by paramyxea and that all microsporidian associations with feminisation are due to co-infection with paramyxea (Short et al., 2012). In a population of the amphipod Gammarus duebeni, breeding experiments demonstrate that the microsporidia D. duebenum and Nosema granulosis are associated with feminisation in the absence of paramyxea. Co-infection of the two microsporidia is no more frequent than expected at random and each parasite is associated with feminisation in the absence of the other. These findings support the original hypothesis that the ability to feminise amphipods has evolved in microsporidia on multiple occasions. Additionally, the occurrence of a non-feminising strain of D. duebenum in Gammarus pulex suggests that different strains vary in their feminising ability, even within microsporidian species. The presence or absence of feminising ability in a particular microsporidian strain should not therefore be generalised to the species as a whole.

  19. Evaluation of toxicity to the amphipod, Hyalella azteca, and to the midge, Chironomus dilutus; and bioaccumulation by the oligochaete, Lumbriculus variegatus, with exposure to PCB-contaminated sediments from Anniston, Alabama

    USGS Publications Warehouse

    Ingersoll, Christopher G.; Steevens, Jeffery A.; MacDonald, Donald D.; Brumbaugh, William G.; Coady, Matthew R.; Farrar, J. Daniel; Lotufo, Guilherme R.; Kemble, Nile E.; Kunz, James L.; Stanley, Jacob K.; Sinclair, Jesse A.

    2014-01-01

    The U.S. Environmental Protection Agency (USEPA) requested that as part of the remedial investigation for the Anniston, Alabama Polychlorinated Biphenyl (PCB) Site (Anniston PCB Site), that Pharmacia Corporation and Solutia Inc. (P/S) perform long-term reproduction toxicity tests with the amphipod, Hyalella azteca, and the midge, Chironomus dilutus, and bioaccumulation tests with the oligochaete, Lumbriculus variegatus, using sediment samples collected from reference locations and from Operable Unit 4 of the Anniston PCB Site. The sediment toxicity testing and sediment bioaccumulation results will be used by ARCADIS U.S., Inc. (ARCADIS) as part of a weight-of-evidence assessment to evaluate risks and establish sediment remediation goals for contaminants to sediment-dwelling organisms inhabiting the Anniston PCB Site. The goal of this study was to characterize relations between sediment chemistry and sediment toxicity and relations between sediment chemistry and sediment bioaccumulation in samples of sediments collected from the Anniston PCB Site. A total of 32 samples were evaluated from six test sites and one reference site to provide a wide range in concentrations of chemicals of potential concern (COPCs) including PCBs in samples of whole sediment. The goal of this study was not to determine the extent of sediment contamination across the Anniston PCB Site. Hence, the test sites or samples collected from within a test site were not selected to represent the spatial extent of sediment contamination across the Anniston PCB Site. Sediment chemistry, pore-water chemistry, and sediment toxicity data were generated for 26 sediment samples from the Anniston PCB Site. All of the samples were evaluated to determine if they qualified as reference sediment samples. Those samples that met the chemical selection criteria and biological selection criteria were identified as reference samples and used to develop the reference envelope for each toxicity test endpoint. Physical

  20. Evaluation of toxicity to the amphipod, Hyalella azteca, and to the midge, Chironomus dilutus; and bioaccumulation by the oligochaete, Lumbriculus variegatus, with exposure to PCB-contaminated sediments from Anniston, Alabama

    USGS Publications Warehouse

    Ingersoll, Christopher G.; Steevens, Jeffery A.; MacDonald, Donald D.; Brumbaugh, William G.; Coady, Matthew R.; Farrar, J. Daniel; Lotufo, Guilherme R.; Kemble, Nile E.; Kunz, James L.; Stanley, Jacob K.; Sinclair, Jesse A.; Ingersoll, Christopher G.; Steevens, Jeffery A.; MacDonald, Donald D.

    2014-01-01

    The U.S. Environmental Protection Agency (USEPA) requested that as part of the remedial investigation for the Anniston, Alabama Polychlorinated Biphenyl (PCB) Site (Anniston PCB Site), that Pharmacia Corporation and Solutia Inc. (P/S) perform long-term reproduction toxicity tests with the amphipod, Hyalella azteca, and the midge, Chironomus dilutus, and bioaccumulation tests with the oligochaete, Lumbriculus variegatus, using sediment samples collected from reference locations and from Operable Unit 4 of the Anniston PCB Site. The sediment toxicity testing and sediment bioaccumulation results will be used by ARCADIS U.S., Inc. (ARCADIS) as part of a weight-of-evidence assessment to evaluate risks and establish sediment remediation goals for contaminants to sediment-dwelling organisms inhabiting the Anniston PCB Site. The goal of this study was to characterize relations between sediment chemistry and sediment toxicity and relations between sediment chemistry and sediment bioaccumulation in samples of sediments collected from the Anniston PCB Site. A total of 32 samples were evaluated from six test sites and one reference site to provide a wide range in concentrations of chemicals of potential concern (COPCs) including PCBs in samples of whole sediment. The goal of this study was not to determine the extent of sediment contamination across the Anniston PCB Site. Hence, the test sites or samples collected from within a test site were not selected to represent the spatial extent of sediment contamination across the Anniston PCB Site. Sediment chemistry, pore-water chemistry, and sediment toxicity data were generated for 26 sediment samples from the Anniston PCB Site. All of the samples were evaluated to determine if they qualified as reference sediment samples. Those samples that met the chemical selection criteria and biological selection criteria were identified as reference samples and used to develop the reference envelope for each toxicity test endpoint. Physical

  1. Transcriptional responses to teflubenzuron exposure in European lobster (Homarus gammarus).

    PubMed

    Olsvik, Pål A; Samuelsen, Ole B; Agnalt, Ann-Lisbeth; Lunestad, Bjørn T

    2015-10-01

    Increasing use of pharmaceutical drugs to delouse farmed salmon raises environmental concerns. This study describes an experiment carried out to elucidate the molecular mechanisms of the antiparasitic drug teflubenzuron on a non-target species, the European lobster. Juvenile lobsters (10.3±0.9 mm carapace length) were fed two environmentally relevant doses of teflubenzuron, corresponding to 5 and 20% of a standard salmon medication (10 mg/kg day), termed low and high dose in this study. After 114 days of dietary exposure, whole-animal accumulation of teflubenzuron was determined. One claw from each animal was collected for transcriptional analysis. Overall, exposed animals showed low cumulative mortality. Six animals, two from the low dose treatment and four from the high dose, showed exoskeletal abnormalities (claw deformities or stiff walking legs). Residual levels of teflubenzuron in juvenile lobster were 2.7-fold higher in the high dose (282 ng/g) compared to the low dose treatment (103 ng/g). The transcriptional examination showed significant effects of teflubenzuron on 21 out of 39 studied genes. At the transcriptional level, environmentally relevant levels of the anti-salmon lice drug impacted genes linked to drug detoxification (cyp3a, cyp6a2, cyp302a, sult1b1, abcc4), cellular stress (hsp70, hsp90, chh), oxidative stress (cat, gpx3) and DNA damage (p53), as well as molting and exoskeleton regulation (chi3l1, ecr, jhl1, chs1, ctbs, gap65, jhel-ces1) in claw tissue (muscle and exoskeleton). In conclusion, teflubenzuron at sub-lethal levels can affect many molecular mechanisms in European lobster claws.

  2. Transcriptional responses to teflubenzuron exposure in European lobster (Homarus gammarus).

    PubMed

    Olsvik, Pål A; Samuelsen, Ole B; Agnalt, Ann-Lisbeth; Lunestad, Bjørn T

    2015-10-01

    Increasing use of pharmaceutical drugs to delouse farmed salmon raises environmental concerns. This study describes an experiment carried out to elucidate the molecular mechanisms of the antiparasitic drug teflubenzuron on a non-target species, the European lobster. Juvenile lobsters (10.3±0.9 mm carapace length) were fed two environmentally relevant doses of teflubenzuron, corresponding to 5 and 20% of a standard salmon medication (10 mg/kg day), termed low and high dose in this study. After 114 days of dietary exposure, whole-animal accumulation of teflubenzuron was determined. One claw from each animal was collected for transcriptional analysis. Overall, exposed animals showed low cumulative mortality. Six animals, two from the low dose treatment and four from the high dose, showed exoskeletal abnormalities (claw deformities or stiff walking legs). Residual levels of teflubenzuron in juvenile lobster were 2.7-fold higher in the high dose (282 ng/g) compared to the low dose treatment (103 ng/g). The transcriptional examination showed significant effects of teflubenzuron on 21 out of 39 studied genes. At the transcriptional level, environmentally relevant levels of the anti-salmon lice drug impacted genes linked to drug detoxification (cyp3a, cyp6a2, cyp302a, sult1b1, abcc4), cellular stress (hsp70, hsp90, chh), oxidative stress (cat, gpx3) and DNA damage (p53), as well as molting and exoskeleton regulation (chi3l1, ecr, jhl1, chs1, ctbs, gap65, jhel-ces1) in claw tissue (muscle and exoskeleton). In conclusion, teflubenzuron at sub-lethal levels can affect many molecular mechanisms in European lobster claws. PMID:26318677

  3. The enemy of my enemy is my friend: intraguild predation between invaders and natives facilitates coexistence with shared invasive prey.

    PubMed

    MacNeil, Calum; Dick, Jaimie T A

    2014-08-01

    Understanding and predicting the outcomes of biological invasions is challenging where multiple invader and native species interact. We hypothesize that antagonistic interactions between invaders and natives could divert their impact on subsequent invasive species, thus facilitating coexistence. From field data, we found that, when existing together in freshwater sites, the native amphipod Gammarus duebeni celticus and a previous invader G. pulex appear to facilitate the establishment of a second invader, their shared prey Crangonyx pseudogracilis. Indeed, the latter species was rarely found at sites where each Gammarus species was present on its own. Experiments indicated that this may be the result of G. d. celticus and G. pulex engaging in more intraguild predation (IGP) than cannibalism; when the 'enemy' of either Gammarus species was present, that is, the other Gammarus species, C. pseudogracilis significantly more often escaped predation. Thus, the presence of mutual enemies and the stronger inter- than intraspecific interactions they engage in can facilitate other invaders. With some invasive species such as C. pseudogracilis having no known detrimental effects on native species, and indeed having some positive ecological effects, we also conclude that some invasions could promote biodiversity and ecosystem functioning.

  4. Interactions among zebra mussel shells, invertebrate prey, and Eurasian ruffe or yellow perch

    USGS Publications Warehouse

    Kolar, C.S.; Fullerton, A.H.; Martin, K.M.; Lamberti, G.A.

    2002-01-01

    The exotic zebra mussel, Dreissena polymorpha, is established in all of the Laurentian Great Lakes and may affect benthivorous fishes by increasing the complexity of benthic substrates and changing energy flow patterns within the food web. Native yellow perch, Perca flavescens, and the nonindigenous Eurasian ruffe, Gymnocephalus cernuus, are benthivores that may compete for limited food resources. As ruffe spread to areas with more dense zebra mussel populations, the zone of interaction among zebra mussels, yellow perch, and ruffe will increase and intensify. In the laboratory, the effect of zebra mussel shells on the ability of these fishes to forage on amphipods (Gammarus pseudolimnaeus) and chironomids (Chironomus plumosus) was examined in light and darkness. In 12 h, ruffe consumed more amphipods than did similar-sized yellow perch, particularly in darkness on bare cobble, and in light within zebra mussels. Amphipods decreased activity more in the presence of ruffe than yellow perch. More amphipods were found in zebra mussel shells than in bare cobble, whether or not fish were present. In darkness, when ruffe consumed more amphipods on bare cobble, amphipods became more associated with zebra mussel shells. Although ruffe consumed more amphipods than yellow perch, perch consumed more chironomids than ruffe on bare cobble. The presence of zebra mussel shells altered the relative consumption of invertebrates in some substrate-light combinations. Experiments such as these help to improve understanding of the direct and indirect effects of predation between and among native and nonindigenous species that may exert structuring forces on the nearshore communities of the Great Lakes currently or in the future.

  5. Short-term bioconcentration studies of Np in freshwater biota

    SciTech Connect

    Poston, T.M.; Klopfer, D.C.; Simmons, M.A. )

    1990-12-01

    Short-term laboratory exposures were conducted to determine the potential accumulation of Np in aquatic organisms. Concentration factors were highest in green algae. Daphnia magna, a filter-feeding crustacean, accumulated Np at levels one order of magnitude greater than the amphipod Gammarus sp., an omnivorous substrate feeder. Accumulation of Np in juvenile rainbow trout (Oncorhynchus mykiss) was highest in carcass (generally greater than 78% of the total body burden) and lowest in fillets. Recommended concentration factors for Np, based on fresh weight, were 300 for green algae, 100 for filter-feeding invertebrates, for nonfilter-feeding invertebrates, 10 for whole fish, and one for fish flesh.

  6. Effects of anthropogenic salinization on biological traits and community composition of stream macroinvertebrates.

    PubMed

    Szöcs, Eduard; Coring, Eckhard; Bäthe, Jürgen; Schäfer, Ralf B

    2014-01-15

    Salinization of rivers resulting from industrial discharge or road-deicing can adversely affect macroinvertebrates. Trait-based approaches are a promising tool in ecological monitoring and may perform better than taxonomy-based approaches. However only little is known how and which biological traits are affected by salinization. We investigated the effects of anthropogenic salinization on macroinvertebrate communities and biological traits in the Werra River, Germany and compared the taxonomic and trait response. We found a change in macroinvertebrate community and trait composition. Communities at saline sites were characterized by the three exotic species Gammarus tigrinus, Apocorophium lacustre and Potamopyrgus antipodarum. The frequencies of trait modalities long life cycle duration, respiration by gill, ovoviviparity, shredder and multivoltinism were statistically significantly increased at saline sites. The trait-based ordination resulted in a higher explained variance than the taxonomy-based ordination, indicating a better performance of the trait-based approach, resulting in a better discrimination between saline and non-saline sites. Our results are in general agreement with other studies from Europe, indicating a trait convergence for saline streams, being dominated by the traits ovoviviparity and multivoltinism. Three further traits (respiration by gill, life cycle duration and shredders) responded strongly to salinization, but this may primarily be attributed to the dominance of a single invasive species, G. tigrinus, at the saline sites in the Werra River.

  7. Environmental monitoring using malformed embryos of the amphipod Monoporeia affinis

    SciTech Connect

    Sundelin, B.; Eriksson, A.K.

    1995-12-31

    Reproduction variables of Monoporeia affinis, such as embryonic malformation were confirmed as the most sensitive variable, when soft bottom microcosms were exposed to metals such as cadmium and lead, arsenic, organic compounds such as 4,5,6 trichloroguaiacol, contaminated sediment from areas impacted by heavy metals and pulp mill effluents. The effects were demonstrated also in low concentrations that did not significantly affect the meiofauna community. The microcosm test-system with high ecological realism could offer a possibility to translate laboratory results to the natural environments. Field surveys outside different types of pulp mills and metal works on the coast of the Gulf of Bothnia have confirmed the laboratory results. Significantly higher levels of malformed embryos of Monoporeia affinis were demonstrated in the impacted areas in comparison with reference areas. The reproduction variables of Monoporeia affinis have been used in the national environmental monitoring program during two years and results indicated possibilities to distinguish between effects of xenobiotica and secondary eutrophication effects, such as unsaturated oxygen condition and occurrence of sulfides, which resulted in increased frequencies of dead eggs but not affected the frequencies of malformed eggs and embryos.

  8. Predicting invasive species impacts: a community module functional response approach reveals context dependencies.

    PubMed

    Paterson, Rachel A; Dick, Jaimie T A; Pritchard, Daniel W; Ennis, Marilyn; Hatcher, Melanie J; Dunn, Alison M

    2015-03-01

    Predatory functional responses play integral roles in predator-prey dynamics, and their assessment promises greater understanding and prediction of the predatory impacts of invasive species. Other interspecific interactions, however, such as parasitism and higher-order predation, have the potential to modify predator-prey interactions and thus the predictive capability of the comparative functional response approach. We used a four-species community module (higher-order predator; focal native or invasive predators; parasites of focal predators; native prey) to compare the predatory functional responses of native Gammarus duebeni celticus and invasive Gammarus pulex amphipods towards three invertebrate prey species (Asellus aquaticus, Simulium spp., Baetis rhodani), thus, quantifying the context dependencies of parasitism and a higher-order fish predator on these functional responses. Our functional response experiments demonstrated that the invasive amphipod had a higher predatory impact (lower handling time) on two of three prey species, which reflects patterns of impact observed in the field. The community module also revealed that parasitism had context-dependent influences, for one prey species, with the potential to further reduce the predatory impact of the invasive amphipod or increase the predatory impact of the native amphipod in the presence of a higher-order fish predator. Partial consumption of prey was similar for both predators and occurred increasingly in the order A. aquaticus, Simulium spp. and B. rhodani. This was associated with increasing prey densities, but showed no context dependencies with parasitism or higher-order fish predator. This study supports the applicability of comparative functional responses as a tool to predict and assess invasive species impacts incorporating multiple context dependencies.

  9. Predicting invasive species impacts: a community module functional response approach reveals context dependencies.

    PubMed

    Paterson, Rachel A; Dick, Jaimie T A; Pritchard, Daniel W; Ennis, Marilyn; Hatcher, Melanie J; Dunn, Alison M

    2015-03-01

    Predatory functional responses play integral roles in predator-prey dynamics, and their assessment promises greater understanding and prediction of the predatory impacts of invasive species. Other interspecific interactions, however, such as parasitism and higher-order predation, have the potential to modify predator-prey interactions and thus the predictive capability of the comparative functional response approach. We used a four-species community module (higher-order predator; focal native or invasive predators; parasites of focal predators; native prey) to compare the predatory functional responses of native Gammarus duebeni celticus and invasive Gammarus pulex amphipods towards three invertebrate prey species (Asellus aquaticus, Simulium spp., Baetis rhodani), thus, quantifying the context dependencies of parasitism and a higher-order fish predator on these functional responses. Our functional response experiments demonstrated that the invasive amphipod had a higher predatory impact (lower handling time) on two of three prey species, which reflects patterns of impact observed in the field. The community module also revealed that parasitism had context-dependent influences, for one prey species, with the potential to further reduce the predatory impact of the invasive amphipod or increase the predatory impact of the native amphipod in the presence of a higher-order fish predator. Partial consumption of prey was similar for both predators and occurred increasingly in the order A. aquaticus, Simulium spp. and B. rhodani. This was associated with increasing prey densities, but showed no context dependencies with parasitism or higher-order fish predator. This study supports the applicability of comparative functional responses as a tool to predict and assess invasive species impacts incorporating multiple context dependencies. PMID:25265905

  10. Predicting invasive species impacts: a community module functional response approach reveals context dependencies

    PubMed Central

    Paterson, Rachel A; Dick, Jaimie T A; Pritchard, Daniel W; Ennis, Marilyn; Hatcher, Melanie J; Dunn, Alison M

    2015-01-01

    Summary Predatory functional responses play integral roles in predator–prey dynamics, and their assessment promises greater understanding and prediction of the predatory impacts of invasive species. Other interspecific interactions, however, such as parasitism and higher-order predation, have the potential to modify predator–prey interactions and thus the predictive capability of the comparative functional response approach. We used a four-species community module (higher-order predator; focal native or invasive predators; parasites of focal predators; native prey) to compare the predatory functional responses of native Gammarus duebeni celticus and invasive Gammarus pulex amphipods towards three invertebrate prey species (Asellus aquaticus, Simulium spp., Baetis rhodani), thus, quantifying the context dependencies of parasitism and a higher-order fish predator on these functional responses. Our functional response experiments demonstrated that the invasive amphipod had a higher predatory impact (lower handling time) on two of three prey species, which reflects patterns of impact observed in the field. The community module also revealed that parasitism had context-dependent influences, for one prey species, with the potential to further reduce the predatory impact of the invasive amphipod or increase the predatory impact of the native amphipod in the presence of a higher-order fish predator. Partial consumption of prey was similar for both predators and occurred increasingly in the order A. aquaticus, Simulium spp. and B. rhodani. This was associated with increasing prey densities, but showed no context dependencies with parasitism or higher-order fish predator. This study supports the applicability of comparative functional responses as a tool to predict and assess invasive species impacts incorporating multiple context dependencies. PMID:25265905

  11. Community Interactions Modify the Effects of Pharmaceutical Exposure: A Microcosm Study on Responses to Propranolol in Baltic Sea Coastal Organisms

    PubMed Central

    Oskarsson, Hanna; Eriksson Wiklund, Ann-Kristin; Thorsén, Gunnar; Danielsson, Gabriela; Kumblad, Linda

    2014-01-01

    This study investigated the uptake and effects of a common human pharmaceutical, propranolol, on the structure and function of a coastal Baltic Sea model community consisting of macroalga (Ceramium tenuicorne), mussels (Mytilus edulis trossulus), amphipods (Gammarus spp.), water and sediment. The most sensitive species, the mussel, was affected to the same extent as in previous single species studies, while the effects on the amphipod and alga were smaller or even positive compared to experiments performed in less complex test systems. The observed cascade of beneficial effects was a result of inter-specific species interactions that buffered for more severe effects. The poor condition of the mussel led to a feeding shift from alga to mussel by the amphipods. The better food quality, due to the dietary shift, counteracted the effects of the exposure. Less amphipod grazing, together with increased levels of nutrients in the water was favourable for the alga, despite the negative effects of propranolol. This microcosm study showed effects on organisms on different organizational levels as well as interactions among the different components resulting in indirect exposure effects of both functional and structural nature. The combination of both direct and indirect effects would not have been detected using simpler single- or even two-species study designs. The observed structural changes would in the natural environment have a long-term influence on ecosystem function, especially in a low-biodiversity ecosystem like the Baltic Sea. PMID:24713620

  12. The life cycle of Huffmanela huffmani Moravec, 1987(Nematoda: Trichosomoididae), an endemic marine-relict parasite of Centrarchidae from a Central Texas spring.

    PubMed

    Worsham, McLean L D; Huffman, David G; Moravec, Frantisek; Gibson, J Randy

    2016-01-01

    The life cycle of the swim bladder nematode Huffmanela huffmani Moravec, 1987 (Trichinelloidea: Trichosomoididae), an endemic parasite of centrarchid fishes in the upper spring run of the San Marcos River in Hays County, Texas, USA, was experimentally completed. The amphipods Hyalella cf. azteca (Saussure), Hyalella sp. and Gammarus sp. were successfully infected with larvated eggs of Huffmanela huffmani. After ingestion of eggs of H. huffmani by experimental amphipods, the first-stage larvae hatch from their eggshells and penetrate through the digestive tract to the hemocoel of the amphipod. Within about 5 days in the hemocoel of the experimental amphipods at 22 °C, the larvae presumably attained the second larval stage and were infective for the experimental centrarchid definitive hosts, Lepomis spp. The minimum incubation period before adult nematodes began laying eggs in the swim bladders of the definitive hosts was found to be about 7.5 months at 22 °C. This is the first experimentally completed life cycle within the Huffmanelinae. PMID:27312028

  13. Organochlorine pesticides and polychlorinated biphenyls in the Arctic Ocean food web.

    PubMed

    Hargrave, B T; Harding, G C; Vass, W P; Erickson, P E; Fowler, B R; Scott, V

    1992-01-01

    Polychlorinated biphenyls (PCBs), polychlorinated camphenes (PCCs) and isomers of DDT and DDE were the predominant organochlorine (OC) hydrocarbons measured in epontic particulate matter, zooplankton, pelagic and benthic amphipods and liver tissue from an abyssal fish collected in the Arctic Ocean. Chlordane, dieldrin and other cyclodienes and hexachlorocyclohexane (HCH) isomers were present at lower concentrations. Levels on a dry weight basis in plankton of various sizes less than 63 microns to 2 mm were similar to those in epontic particulate matter, but on a lipid weight basis, concentrations in smaller plankton were two to five times higher. Organochlorines in amphipods and liver from the glacial eelpout Lycodes frigidus exceeded levels in zooplankton by up to an order of magnitude. Large benthic lysianassid amphipods (Tmetonyx cicada, Anonyx nugax and Eurythenes gryllus) accumulated higher concentrations on a dry and lipid weight basis than small species (Onisimus spp. and Andaniexis spp.) or the under-ice gammaridean amphipod (Gammarus wilkitzkii). No significant differences in OC levels were measured in benthic amphipods collected at different times. However, concentrations in large zooplankton (greater than 500 microns) collected in August, dominated by adult copepods and ctenophores, contained concentrations of alpha-HCH, chlordane isomers and other cyclodienes that were two to four times higher than levels in May. Ratios of alpha-HCH: gamma-HCH (5 to 10) were similar to those in seawater collected simultaneously but there was no difference in ratios in various size categories of planktonic and benthic crustaceans indicating no selective accumulation or metabolic alteration of these isomers. Ratios of cis-chlordane:trans-chlordane concentrations were lower in all sizes of zooplankton (2 to 3) than in shelf amphipods (3 to 6) which corresponded to an increase in the ratio with depth. Higher ratios of DDT:DDE in plankton (2 to 6) than in amphipods (1 to 2

  14. Zoogeography of epigean freshwater Amphipoda (Crustacea) in Romania: fragmented distributions and wide altitudinal variability.

    PubMed

    Copilaș-Ciocianu, Denis; Grabowski, Michał; Pârvulescu, Lucian; Petrusek, Adam

    2014-12-08

    Inland epigean freshwater amphipods of Romania are diverse and abundant for this region has a favourable geographical position between the Balkans and the Black Sea. Excluding Ponto-Caspian species originating in brackish waters and freshwater subterranean taxa, there are 11 formally recognized epigean freshwater species recorded from this country. They belong to 3 genera, each representing a different family: Gammarus (Gammaridae, 8 species or species complexes), Niphargus (Niphargidae, 2 epigean species) and Synurella (Crangonyctidae, one species). Their large-scale distribution patterns nevertheless remain obscure due to insufficient data, consequently limiting biogeographical interpretations. We provide extensive new data with high resolution distribution maps, thus improving the knowledge of the ranges of these taxa. Gammarus species display substantial altitudinal variability and patchy, fragmented distribution patterns. They occur abundantly, particularly in springs and streams, from lowlands to sub-mountainous and mountainous regions. In the light of recent molecular research, we hypothesize that the complex geomorphological dynamics of the Carpathian region during the Late Tertiary probably contributed to their allopatric distribution pattern. Contrasting with Gammarus, the genera Niphargus and Synurella exhibit low altitudinal variability, broad ecological valences and overlapping distributions, being widespread throughout the lowlands. The current distribution of N. hrabei and N. valachicus seems to be linked to the extent of the Paratethys during the Early Pliocene or Pleistocene. We further discuss the taxonomic validity of two synonymized and one apparently undescribed taxon, and provide an updated pictorial identification key that includes all taxa and forms discussed in our study. The mosaic distribution of epigean freshwater amphipod species in Romania shows that this region is particularly suitable for phylo- and biogeographical analyses of this

  15. Novel membrane-associated prostaglandin E synthase-2 from crustacean arthropods.

    PubMed

    Hansen, Kristella; Varvas, Külliki; Järving, Ivar; Samel, Nigulas

    2014-08-01

    Prostaglandins (PG) have been shown to play important physiological roles in insects and marine invertebrates, yet the knowledge of their biosynthetic pathways is often lacking. Recently, we described cyclooxygenases in two amphipod crustaceans, Gammarus sp. and Caprella sp. In the present study, we report the cloning and characterization of prostaglandin E synthases (PGES) from the same organisms. The amphipod membrane-bound PGES-2-type enzymes share about 40% of the amino acid sequence identity with human mPGES-2, contain a conserved Cys110-x-x-Cys113 motif and have very low heme-binding affinity. The recombinant enzymes purified in the absence of dithiothreitol specifically catalyze the isomerization of PGH2 into PGE2. The PGES activity is increased in the presence of reduced glutathione and inhibited with a sulfhydryl group inhibitor. We assume that the amphipod mPGES-2, unlike in their mammalian counterparts, is responsible for PGE2 synthesis, not only in vitro but also in vivo.

  16. Genetic diversity in two introduced biofouling amphipods (Amphipods valida and Jassa marmorata) along the Pacific North American coast: investigation into molecular identification and cryptic diversity

    EPA Science Inventory

    We investigated patterns of genetic diversity among invasive populations of A. valida and J. marmorata from the Pacific North American coast to assess the accuracy of morphological identification and determine whether or not cryptic diversity and multiple introductions contribute...

  17. Significance of Xenobiotic Metabolism for Bioaccumulation Kinetics of Organic Chemicals in Gammarus pulex

    PubMed Central

    2012-01-01

    Bioaccumulation and biotransformation are key toxicokinetic processes that modify toxicity of chemicals and sensitivity of organisms. Bioaccumulation kinetics vary greatly among organisms and chemicals; thus, we investigated the influence of biotransformation kinetics on bioaccumulation in a model aquatic invertebrate using fifteen 14C-labeled organic xenobiotics from diverse chemical classes and physicochemical properties (1,2,3-trichlorobenzene, imidacloprid, 4,6-dinitro-o-cresol, ethylacrylate, malathion, chlorpyrifos, aldicarb, carbofuran, carbaryl, 2,4-dichlorophenol, 2,4,5-trichlorophenol, pentachlorophenol, 4-nitrobenzyl-chloride, 2,4-dichloroaniline, and sea-nine (4,5-dichloro-2-octyl-3-isothiazolone)). We detected and identified metabolites using HPLC with UV and radio-detection as well as high resolution mass spectrometry (LTQ-Orbitrap). Kinetics of uptake, biotransformation, and elimination of parent compounds and metabolites were modeled with a first-order one-compartment model. Bioaccumulation factors were calculated for parent compounds and metabolite enrichment factors for metabolites. Out of 19 detected metabolites, we identified seven by standards or accurate mass measurements and two via pathway analysis and analogies to other compounds. 1,2,3-Trichlorobenzene, imidacloprid, and 4,6-dinitro-o-cresol were not biotransformed. Dietary uptake contributed little to overall uptake. Differentiation between parent and metabolites increased accuracy of bioaccumulation parameters compared to total 14C measurements. Biotransformation dominated toxicokinetics and strongly affected internal concentrations of parent compounds and metabolites. Many metabolites reached higher internal concentrations than their parents, characterized by large metabolite enrichment factors. PMID:22321051

  18. Feeding ecology of long-tailed ducks Clangula hyemalis wintering on the Nantucket Shoals

    USGS Publications Warehouse

    White, Timothy P.; Veit, Richard R.; Perry, Matthew C.

    2009-01-01

    A substantial proportion, perhaps 30%, of the North American breeding population of Long-tailed Ducks (Clangula hyemalis) winter in the vicinity of Nantucket Island, Massachusetts. These birds spend the night on Nantucket Sound and commute during daylight hours to the Nantucket Shoals, which extend about 65 km offshore from the southeastern corner of Nantucket. Strip transects done from a single-engine plane in 1997 and 1998 indicated that Long-tailed Ducks foraged over the shallower (<= 20 m depth) portions of the Nantucket Shoals, up to 70 km offshore. Diet analyses of ten birds collected in February 1999 and five in December 2006 showed that they fed principally (106.6 +/- 42.0 individuals per crop) on Gammarus annulatus, a pelagic amphipod that often forms large aggregations, and is consumed by several species of fish and marine mammals. Our findings emphasize the importance of conservation of the Nantucket Shoals and the prevention of oil spills or other potentially harmful accidents.

  19. Hexachlorobenzene uptake by fathead minnows and macroinvertebrates in recirculating sediment/water systems

    SciTech Connect

    Schuytema, G.S.; Krawczyk, D.F.; Griffis, W.L.; Nebeker, A.V.; Robideaux, M.L.

    1990-01-01

    Fathead minnow (Pimephales promelas), the worm, Lumbriculus variegatus, and the amphipods Hyalella azteca and Gammarus lacustris were exposed to hexachlorobenzene (HCB) in water with and without a bed of HCB-spiked sediment. Water HCB concentrations were maintained by recirculation through HCB-packed columns. Recirculating HCB-bound particulates and possibly eroded HCB particulates were an added source of HCB in addition to the sediment bed. Significant bioaccumulation of HCB in animal tissues was observed in water-only and water-sediment exposures. The presence of the HCB-spiked sediment did not result in a significant increase in the uptake of HCB by the organisms, but there was a substantial increase in sediment HCB levels over time. Higher tissue HCB levels in aquaria without sediment suggest that the sediment was a more efficient sink for HCB than the organisms.

  20. Arctic sea-ice ridges—Safe heavens for sea-ice fauna during periods of extreme ice melt?

    NASA Astrophysics Data System (ADS)

    Gradinger, Rolf; Bluhm, Bodil; Iken, Katrin

    2010-01-01

    The abundances and distribution of metazoan within-ice meiofauna (13 stations) and under-ice fauna (12 stations) were investigated in level sea ice and sea-ice ridges in the Chukchi/Beaufort Seas and Canada Basin in June/July 2005 using a combination of ice coring and SCUBA diving. Ice meiofauna abundance was estimated based on live counts in the bottom 30 cm of level sea ice based on triplicate ice core sampling at each location, and in individual ice chunks from ridges at four locations. Under-ice amphipods were counted in situ in replicate ( N=24-65 per station) 0.25 m 2 quadrats using SCUBA to a maximum water depth of 12 m. In level sea ice, the most abundant ice meiofauna groups were Turbellaria (46%), Nematoda (35%), and Harpacticoida (19%), with overall low abundances per station that ranged from 0.0 to 10.9 ind l -1 (median 0.8 ind l -1). In level ice, low ice algal pigment concentrations (<0.1-15.8 μg Chl a l -1), low brine salinities (1.8-21.7) and flushing from the melting sea ice likely explain the low ice meiofauna concentrations. Higher abundances of Turbellaria, Nematoda and Harpacticoida also were observed in pressure ridges (0-200 ind l -1, median 40 ind l -1), although values were highly variable and only medians of Turbellaria were significantly higher in ridge ice than in level ice. Median abundances of under-ice amphipods at all ice types (level ice, various ice ridge structures) ranged from 8 to 114 ind m -2 per station and mainly consisted of Apherusa glacialis (87%), Onisimus spp. (7%) and Gammarus wilkitzkii (6%). Highest amphipod abundances were observed in pressure ridges at depths >3 m where abundances were up to 42-fold higher compared with level ice. We propose that the summer ice melt impacted meiofauna and under-ice amphipod abundance and distribution through (a) flushing, and (b) enhanced salinity stress at thinner level sea ice (less than 3 m thickness). We further suggest that pressure ridges, which extend into deeper, high

  1. Diets of Lesser Scaup during spring migration throughout the upper-Midwest are consistent with the spring condition hypothesis

    USGS Publications Warehouse

    Anteau, M.J.; Afton, A.D.

    2008-01-01

    The spring condition hypothesis (SCH) states that the current decline of the North American scaup population (Lesser [Aythya affinis] and Greater Scaup [A. marila] combined) is due to a decline in quality or availability of scaup foods on wintering, spring migration, or breeding areas that has caused a reduction in female body condition and subsequent reproductive success. Our previous research indicated that forage quality in diets of Lesser Scaup (hereafter scaup) at two sites in Northwestern Minnesota was lower in springs 2000-2001 than that reported for springs 1986-1988, consistent with the SCH. Accordingly, we further tested the SCH at a landscape scale, by comparing amounts of amphipods in diets (index of forage quality) of scaup (N = 263) collected in springs 2003-2005 from seven eco-physiographic regions in Iowa, Minnesota, and North Dakota in relation to data from Northwestern Minnesota during springs 2000-2001. We found that aggregate percentages of Gammarus lacustris and Hyalella azteca (amphipods) in scaup diets during springs 2000-2001 in Northwest Minnesota were similar to those in the Iowa Prairie Pothole, Minnesota Morainal, Minnesota Glaciated Plains, Red River Valley, and Northwestern Minnesota in springs 2003-2005; however, scaup consumed relatively higher aggregate percentages of Gammarus lacustris and Hyalella azteca in North Dakota Missouri Coteau and North Dakota Glaciated Plains. Females in Iowa were over three times less likely to have consumed food than those in North Dakota, despite previous research indicating similar foraging rates among these regions. Mean mass of scaup diet samples throughout the upper-Midwest were 77 mg (49%) and 87 mg (52%) lower than those of historical studies in Minnesota and Manitoba, respectively. We conclude that there has been a decrease in forage quality for scaup in Iowa and Minnesota and a decrease in the amount of forage consumed throughout the upper-Midwest, consistent with the SCH.

  2. Multidimensionality in host manipulation mimicked by serotonin injection.

    PubMed

    Perrot-Minnot, Marie-Jeanne; Sanchez-Thirion, Kevin; Cézilly, Frank

    2014-12-01

    Manipulative parasites often alter the phenotype of their hosts along multiple dimensions. 'Multidimensionality' in host manipulation could consist in the simultaneous alteration of several physiological pathways independently of one another, or proceed from the disruption of some key physiological parameter, followed by a cascade of effects. We compared multidimensionality in 'host manipulation' between two closely related amphipods, Gammarus fossarum and Gammarus pulex, naturally and experimentally infected with Pomphorhynchus laevis (Acanthocephala), respectively. To that end, we calculated in each host-parasite association the effect size of the difference between infected and uninfected individuals for six different traits (activity, phototaxis, geotaxis, attraction to conspecifics, refuge use and metabolic rate). The effects sizes were highly correlated between host-parasite associations, providing evidence for a relatively constant 'infection syndrome'. Using the same methodology, we compared the extent of phenotypic alterations induced by an experimental injection of serotonin (5-HT) in uninfected G. pulex to that induced by experimental or natural infection with P. laevis. We observed a significant correlation between effect sizes across the six traits, indicating that injection with 5-HT can faithfully mimic the 'infection syndrome'. This is, to our knowledge, the first experimental evidence that multidimensionality in host manipulation can proceed, at least partly, from the disruption of some major physiological mechanism.

  3. Multidimensionality in host manipulation mimicked by serotonin injection.

    PubMed

    Perrot-Minnot, Marie-Jeanne; Sanchez-Thirion, Kevin; Cézilly, Frank

    2014-12-01

    Manipulative parasites often alter the phenotype of their hosts along multiple dimensions. 'Multidimensionality' in host manipulation could consist in the simultaneous alteration of several physiological pathways independently of one another, or proceed from the disruption of some key physiological parameter, followed by a cascade of effects. We compared multidimensionality in 'host manipulation' between two closely related amphipods, Gammarus fossarum and Gammarus pulex, naturally and experimentally infected with Pomphorhynchus laevis (Acanthocephala), respectively. To that end, we calculated in each host-parasite association the effect size of the difference between infected and uninfected individuals for six different traits (activity, phototaxis, geotaxis, attraction to conspecifics, refuge use and metabolic rate). The effects sizes were highly correlated between host-parasite associations, providing evidence for a relatively constant 'infection syndrome'. Using the same methodology, we compared the extent of phenotypic alterations induced by an experimental injection of serotonin (5-HT) in uninfected G. pulex to that induced by experimental or natural infection with P. laevis. We observed a significant correlation between effect sizes across the six traits, indicating that injection with 5-HT can faithfully mimic the 'infection syndrome'. This is, to our knowledge, the first experimental evidence that multidimensionality in host manipulation can proceed, at least partly, from the disruption of some major physiological mechanism. PMID:25339729

  4. Multidimensionality in host manipulation mimicked by serotonin injection

    PubMed Central

    Perrot-Minnot, Marie-Jeanne; Sanchez-Thirion, Kevin; Cézilly, Frank

    2014-01-01

    Manipulative parasites often alter the phenotype of their hosts along multiple dimensions. ‘Multidimensionality’ in host manipulation could consist in the simultaneous alteration of several physiological pathways independently of one another, or proceed from the disruption of some key physiological parameter, followed by a cascade of effects. We compared multidimensionality in ‘host manipulation’ between two closely related amphipods, Gammarus fossarum and Gammarus pulex, naturally and experimentally infected with Pomphorhynchus laevis (Acanthocephala), respectively. To that end, we calculated in each host–parasite association the effect size of the difference between infected and uninfected individuals for six different traits (activity, phototaxis, geotaxis, attraction to conspecifics, refuge use and metabolic rate). The effects sizes were highly correlated between host–parasite associations, providing evidence for a relatively constant ‘infection syndrome’. Using the same methodology, we compared the extent of phenotypic alterations induced by an experimental injection of serotonin (5-HT) in uninfected G. pulex to that induced by experimental or natural infection with P. laevis. We observed a significant correlation between effect sizes across the six traits, indicating that injection with 5-HT can faithfully mimic the ‘infection syndrome’. This is, to our knowledge, the first experimental evidence that multidimensionality in host manipulation can proceed, at least partly, from the disruption of some major physiological mechanism. PMID:25339729

  5. Development of Reduced Sediment Volume Test Procedures for the Estuarine Amphipod Leptocheirus plumulosus

    EPA Science Inventory

    The sediment volume requirements of toxicity and bioaccumulation bioassays affect the cost of the assessment related to field collection, transportation, storage, disposal, and labor associated with organism recovery at bioassay termination. Our objective was to assess four redu...

  6. Redescription of the rare amphipod crustacean Pseudaeginella montoucheti (Quitete, 1971) from Brazil

    PubMed Central

    Lacerda, Mariana Baptista; Takeuchi, Ichiro; Masunari, Setuko

    2011-01-01

    Abstract Pseudaeginella montoucheti (Quitete, 1971) is redescribed based on newly collected specimens from red and brown algae and tubiculous polychaete colony that were obtained from shallow waters at Tamboretes Archipelago, Balneário Barra do Sul and Sepultura Beach, Bombinhas, Santa Catarina State, Brazil. Of 10 species of Pseudaeginella so far reported, Pseudaeginella montoucheti is closest to Pseudaeginella sanctipauli Laubitz, 1995, but differs from the latter by having more numerous body spines including ventro-lateral ones over gills on pereonites 3 and 4, and the antenna 1 length measuring half body length. An identification key for Pseudaeginella species and a checklist of Caprellidea occurring along the Brazilian coasts are also presented. PMID:22207787

  7. Retention of ice-associated amphipods: possible consequences for an ice-free Arctic Ocean.

    PubMed

    Berge, J; Varpe, O; Moline, M A; Wold, A; Renaud, P E; Daase, M; Falk-Petersen, S

    2012-12-23

    Recent studies predict that the Arctic Ocean will have ice-free summers within the next 30 years. This poses a significant challenge for the marine organisms associated with the Arctic sea ice, such as marine mammals and, not least, the ice-associated crustaceans generally considered to spend their entire life on the underside of the Arctic sea ice. Based upon unique samples collected within the Arctic Ocean during the polar night, we provide a new conceptual understanding of an intimate connection between these under-ice crustaceans and the deep Arctic Ocean currents. We suggest that downwards vertical migrations, followed by polewards transport in deep ocean currents, are an adaptive trait of ice fauna that both increases survival during ice-free periods of the year and enables re-colonization of sea ice when they ascend within the Arctic Ocean. From an evolutionary perspective, this may have been an adaptation allowing success in a seasonally ice-covered Arctic. Our findings may ultimately change the perception of ice fauna as a biota imminently threatened by the predicted disappearance of perennial sea ice.

  8. The magnetic orientation of the Antarctic amphipod Gondogeneia antarctica is cancelled by very weak radiofrequency fields.

    PubMed

    Tomanova, K; Vacha, M

    2016-06-01

    Studies on weak man-made radiofrequency (RF) electromagnetic fields affecting animal magnetoreception aim for a better understanding of the reception mechanism and also point to a new phenomenon having possible consequences in ecology and environmental protection. RF impacts on magnetic compasses have recently been demonstrated in migratory birds and other vertebrates. We set out to investigate the effect of RF on the magnetic orientation of the Antarctic krill species Gondogeneia antarctica, a small marine crustacean widespread along the Antarctic littoral line. Here, we show that upon release, G. antarctica (held under laboratory conditions) escaped in the magnetically seaward direction along the magnetic sea-land axis (y-axis) of the home beach. However, the animals were disoriented after being exposed to RF. Orientation was lost not only in an RF field with a magnetic flux density of 20 nT, as expected according to the literature, but even under the 2 nT originally intended as a control. Our results extend recent findings of the extraordinary sensitivity of animal magnetoreception to weak RF fields in marine invertebrates.

  9. Evaluation of reduced sediment volume procedures for acute toxicity tests using the estuarine amphipod Leptocheirus plumulosus.

    PubMed

    Stanley, Jacob K; Kennedy, Alan J; Farrar, J Daniel; Mount, David R; Steevens, Jeffery A

    2010-12-01

    The volume of sediment required to perform a sediment toxicity bioassay is a major driver of the overall cost associated with that bioassay. Sediment volume affects bioassay cost because of sediment collection, transportation, storage, and disposal costs as well as labor costs associated with organism recovery at the conclusion of the exposure. The objective of the current study was to evaluate reduced sediment volume versions of the standard U.S. Environmental Protection Agency (U.S. EPA) 10-d acute Leptocheirus plumulosus method that uses a beaker size of 1,000 ml and 20 organisms. The test design used evaluated the effects of beaker size (250 and 100 ml) and associated sediment volume (75 and 30 ml, respectively) as well as organism loading density (10 and 20 organisms) on test endpoint responsiveness relative to the standard 10-d test method. These comparisons were completed with three different types of contaminated sediments: a field-collected polycyclic aromatic hydrocarbon (PAH)-contaminated sediment, a lead-spiked control sediment, and a control sediment spiked with mineral oil. Assessment criteria included test endpoint sensitivity, endpoint consistency, statistical power, water quality, and logistical assessments. Results indicate that the current U.S. EPA method is preferable to the reduced sediment volume methods we assessed, but that a 250-ml beaker/10 organism experimental design is of comparable utility and may be advantageous when reduced sediment volumes are desirable because of high contaminant (spiking studies) or sediment disposal costs. In addition, the results of the current study provide toxicity reference values for PAHs, lead, and an oil surrogate for petroleum hydrocarbons. PMID:20890914

  10. Islands beneath islands: phylogeography of a groundwater amphipod crustacean in the Balearic archipelago

    PubMed Central

    2011-01-01

    Background Metacrangonyctidae (Amphipoda, Crustacea) is an enigmatic continental subterranean water family of marine origin (thalassoid). One of the species in the genus, Metacrangonyx longipes, is endemic to the Balearic islands of Mallorca and Menorca (W Mediterranean). It has been suggested that the origin and distribution of thalassoid crustaceans could be explained by one of two alternative hypotheses: (1) active colonization of inland freshwater aquifers by a marine ancestor, followed by an adaptative shift; or (2) passive colonization by stranding of ancestral marine populations in coastal aquifers during marine regressions. A comparison of phylogenies, phylogeographic patterns and age estimations of clades should discriminate in favour of one of these two proposals. Results Phylogenetic relationships within M. longipes based on three mitochondrial DNA (mtDNA) and one nuclear marker revealed five genetically divergent and geographically structured clades. Analyses of cytochrome oxidase subunit 1 (cox1) mtDNA data showed the occurrence of a high geographic population subdivision in both islands, with current gene flow occurring exclusively between sites located in close proximity. Molecular-clock estimations dated the origin of M. longipes previous to about 6 Ma, whereas major cladogenetic events within the species took place between 4.2 and 2.0 Ma. Conclusions M. longipes displayed a surprisingly old and highly fragmented population structure, with major episodes of cladogenesis within the species roughly correlating with some of the major marine transgression-regression episodes that affected the region during the last 6 Ma. Eustatic changes (vicariant events) -not active range expansion of marine littoral ancestors colonizing desalinated habitats-explain the phylogeographic pattern observed in M. longipes. PMID:21791038

  11. Evaluation of Reduced Sediment Volume Procedures for Acute Toxicity Tests Using the Estuarine Amphipod Leptocheirus plumulosus

    EPA Science Inventory

    The volume of sediment required to perform a sediment toxicity bioassay is a major driver of the overall cost associated with that bioassay. Sediment volume affects bioassay cost due to sediment collection, transportation, storage, and disposal costs as well as labor costs assoc...

  12. Status of the amphipod Diporeia ssp. in coastal waters of the Laurentian Great Lakes

    EPA Science Inventory

    Diporeia has historically been the dominant benthic macroinvertebrate in deeper waters of the Laurentian Great Lakes, and its abundance has been proposed as an indicator of ecological condition. In 2010, the USEPA incorporated the Great Lakes into the National Coastal Condition A...

  13. BENTHIC MACROALGAE, DISSOLVED SULFIDES, AND AMPHIPODS IN SURFICIAL SEDIMENTS OF YAQUINA BAY ESTUARY, OREGON, USA

    EPA Science Inventory

    Surveys of benthic green macroalgae at two sites in Yaquina Bay Estuary, Oregon, in 1999 showed that percent cover and biomass values in June were much higher at one site, Idaho Point, than at the other site, Coquille Point. The frequency of detectable hydrogen sulfide odor late...

  14. Potential for parasite-induced biases in aquatic invertebrate population studies

    USGS Publications Warehouse

    Fisher, Justin D.L.; Mushet, David M.; Stockwell, Craig A.

    2014-01-01

    Recent studies highlight the need to include estimates of detection/capture probability in population studies. This need is particularly important in studies where detection and/or capture probability is influenced by parasite-induced behavioral alterations. We assessed potential biases associated with sampling a population of the amphipod Gammarus lacustris in the presence of Polymorphus spp. acanthocephalan parasites shown to increase positive phototaxis in their amphipod hosts. We trapped G. lacustris at two water depths (benthic and surface) and compared number of captures and number of parasitized individuals at each depth. While we captured the greatest number of G. lacustris individuals in benthic traps, parasitized individuals were captured most often in surface traps. These results reflect the phototaxic movement of infected individuals from benthic locations to sunlit surface waters. We then explored the influence of varying infection rates on a simulated population held at a constant level of abundance. Simulations resulted in increasingly biased abundance estimates as infection rates increased. Our results highlight the need to consider parasite-induced biases when quantifying detection and/or capture probability in studies of aquatic invertebrate populations.

  15. Endangered cave crustacean could be water quality indicator in Illinois Karst Region

    NASA Astrophysics Data System (ADS)

    Showstrack, Randy

    Some of the rolling, rural countryside of southwestern Illinois has become just a 20-minute commute from the sprawling city of St. Louis, Missouri, across the Mississippi River, now that newly built roads have opened up the landscape. But as more houses rise in rapidly developing bedroom communities, increasing levels of coliform bacteria—probably originating from septic systems and livestock—are being found in the groundwater. Trace amounts of pesticides, including atrazine, also are present.These contaminants, in large enough quantities, can pollute groundwater and cause public health problems. They also appear to be responsible for the decreased habitat and population of a little-known cave-dwelling crustacean, the Illinois Cave Amphipod (Gammarus acherondytes), a tailless shrimp that can grow up to 20 mm in length and that swims in underground streams in cave dark zones. Decreased dissolved oxygen content in the streams, resulting from land development activities that can cause faster surface runoff, also may affect the amphipod.

  16. Pronounced and prevalent intersexuality does not impede the ‘Demon Shrimp’ invasion

    PubMed Central

    Green Etxabe, Amaia; Short, Stephen; Flood, Tim; Johns, Tim

    2015-01-01

    Crustacean intersexuality is widespread and often linked to infection by sex-distorting parasites. However, unlike vertebrate intersexuality, its association with sexual dysfunction is unclear and remains a matter of debate. The ‘Demon Shrimp,’ Dikerogammarus haemobaphes, an amphipod that has invaded continental waterways, has recently become widespread in Britain. Intersexuality has been noted in D. haemobaphes but not investigated further. We hypothesise that a successful invasive population should not display a high prevalence of intersexuality if this condition represents a truly dysfunctional phenotype. In addition, experiments have indicated that particular parasite burdens in amphipods may facilitate invasions. The rapid and ongoing invasion of British waterways represents an opportunity to determine whether these hypotheses are consistent with field observations. This study investigates the parasites and sexual phenotypes of D. haemobaphes in British waterways, characterising parasite burdens using molecular screening, and makes comparisons with the threatened Gammarus pulex natives. We reveal that invasive and native populations have distinct parasitic profiles, suggesting the loss of G. pulex may have parasite-mediated eco-system impacts. Furthermore, the parasite burdens are consistent with those previously proposed to facilitate biological invasions. Our study also indicates that while no intersexuality occurs in the native G. pulex, approximately 50% of D. haemobaphes males present pronounced intersexuality associated with infection by the microsporidian Dictyocoela berillonum. This unambiguously successful invasive population presents, to our knowledge, the highest reported prevalence of male intersexuality. This is the clearest evidence to date that such intersexuality does not represent a form of debilitating sexual dysfunction that negatively impacts amphipod populations. PMID:25699206

  17. Bioaccumulation of Toxoplasma and Cryptosporidium by the crustacean Gammarus fossarum: involvement in biomonitoring survey and trophic transfer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The protozoans Toxoplasma gondii and Cryptosporidium parvum are public health priorities and their oocysts can persist in environment for long time. They are present in various watercourses as recreational, surface, drinking, river, and seawater and could interact with organisms. To evaluate the cap...

  18. 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.

  19. Combined effects of drought and the fungicide tebuconazole on aquatic leaf litter decomposition.

    PubMed

    Pesce, Stéphane; Zoghlami, Olfa; Margoum, Christelle; Artigas, Joan; Chaumot, Arnaud; Foulquier, Arnaud

    2016-04-01

    Loss of biodiversity and altered ecosystem functioning are driven by the cumulative effects of multiple natural and anthropogenic stressors affecting both quantity and quality of water resources. Here we performed a 40-day laboratory microcosm experiment to assess the individual and combined effects of drought and the model fungicide tebuconazole (TBZ) on leaf litter decomposition (LLD), a fundamental biogeochemical process in freshwater ecosystems. Starting out from a worst-case scenario perspective, leaf-associated microbial communities were exposed to severe drought conditions (four 5-day drought periods alternated with 4-day immersion periods) and/or a chronic exposure to TBZ (nominal concentration of 20μgL(-1)). We assessed the direct effects of drought and fungicide on the structure (biomass, diversity) and activity (extracellular enzymatic potential) of fungal and bacterial assemblages colonizing leaves. We also investigated indirect effects on the feeding rates of the amphipod Gammarus fossarum on leaves previously exposed to drought and/or TBZ contamination. Results indicate a stronger effect of drought stress than fungicide contamination under the experimental conditions applied. Indeed, the drought stress strongly impacted microbial community structure and activities, inhibiting the LLD process and leading to cascading effects on macroinvertebrate feeding. However, despite the lack of significant effect of TBZ applied alone, the effects of drought on microbial functions (i.e., decrease in LLD and in enzymatic activities) and on Gammarus feeding rates were more pronounced when drought and TBZ stresses were applied together. In a perspective of ecological risk assessment and ecosystem management for sustainability, these findings stress the need for deeper insight into how multiple stressors can affect the functioning of aquatic ecosystems and associated services. PMID:26859779

  20. To bite, or not to bite? A quantitative comparison of foraging strategies among three brackish crustaceans feeding on leaf litters

    NASA Astrophysics Data System (ADS)

    Mancinelli, Giorgio

    2012-09-01

    A computerized image analysis technique was implemented to evaluate the damage done to leaf litters by macrophagous crustaceans characterized by different feeding strategies. In addition, a foraging strategy index (FSI) was tested to provide a quantitative estimation of both inter- and intra-specific, density-dependent changes in feeding strategies. Laboratory trials were run with the isopods Idotea baltica and Lekanesphaera hookeri and the amphipod Gammarus aequicauda. The effect of their feeding activities was tested on decaying leaves of Cymodocea nodosa and Phragmites australis. In addition, tests were run using three different abundances of each species to assess the occurrence of density-dependent shifts in feeding strategies. Independently from the leaf litter type, opposite foraging strategies characterized the isopods. Idotea baltica shredded the leaf blade heavily, whereas L. hookeri scraped the leaf surface removing the epidermis. Qualitative observations corresponded to consistent variations in FSI values, with Idotea showing the lowest and Lekanesphaera the highest FSI values. Leaves consumed by G. aequicauda, conversely, were characterized by both shredding and scraping damages, corresponding to intermediate FSI values compared to those measured for the isopods. Furthermore, negligible density-dependent changes in FSI values occurred for both isopods; Gammarus, in contrast, showed a significant shift in trophic strategies, with FSI values close to that observed for Lekanesphaera at high densities and to Idotea at low densities of conspecifics, respectively. The methodology and the FSI index herein presented provided an effective, quantitative assessment of species-specific differences in the feeding strategy of three ubiquitous components of Mediterranean detritivorous epifauna, for which only qualitative, phenomenological descriptions have been to date provided.

  1. Combined effects of drought and the fungicide tebuconazole on aquatic leaf litter decomposition.

    PubMed

    Pesce, Stéphane; Zoghlami, Olfa; Margoum, Christelle; Artigas, Joan; Chaumot, Arnaud; Foulquier, Arnaud

    2016-04-01

    Loss of biodiversity and altered ecosystem functioning are driven by the cumulative effects of multiple natural and anthropogenic stressors affecting both quantity and quality of water resources. Here we performed a 40-day laboratory microcosm experiment to assess the individual and combined effects of drought and the model fungicide tebuconazole (TBZ) on leaf litter decomposition (LLD), a fundamental biogeochemical process in freshwater ecosystems. Starting out from a worst-case scenario perspective, leaf-associated microbial communities were exposed to severe drought conditions (four 5-day drought periods alternated with 4-day immersion periods) and/or a chronic exposure to TBZ (nominal concentration of 20μgL(-1)). We assessed the direct effects of drought and fungicide on the structure (biomass, diversity) and activity (extracellular enzymatic potential) of fungal and bacterial assemblages colonizing leaves. We also investigated indirect effects on the feeding rates of the amphipod Gammarus fossarum on leaves previously exposed to drought and/or TBZ contamination. Results indicate a stronger effect of drought stress than fungicide contamination under the experimental conditions applied. Indeed, the drought stress strongly impacted microbial community structure and activities, inhibiting the LLD process and leading to cascading effects on macroinvertebrate feeding. However, despite the lack of significant effect of TBZ applied alone, the effects of drought on microbial functions (i.e., decrease in LLD and in enzymatic activities) and on Gammarus feeding rates were more pronounced when drought and TBZ stresses were applied together. In a perspective of ecological risk assessment and ecosystem management for sustainability, these findings stress the need for deeper insight into how multiple stressors can affect the functioning of aquatic ecosystems and associated services.

  2. The Influence of Allochthonous Leaf Detritus on the Occurrence of Crustacean Detritivores in the Soft-bottom Macrobenthos of the Po River Delta Area (northwestern Adriatic Sea)

    NASA Astrophysics Data System (ADS)

    Mancinelli, G.; Rossi, L.

    2002-05-01

    Core samples were examined quarterly at two coastal sites (S1 and S2) and at an offshore station (S3) located in the Po River delta area (northwestern Adriatic Sea). Analyses focused on (i) occurrence of coarse detritus of allochthonous origin in the sedimentary matrix and (ii) the relative influence of macrodetritus enrichment and other environmental factors on the vagile macrofauna. Plant debris occurred in site S1 sediments only in summer and autumn; in contrast, fragments of the phanerogams Cymodocea nodosa and Zostera spp. were found in site S2 sediment throughout the sampling period. Sediments from the offshore site S3 were characterized by negligible plant material, even though in summer and autumn samples debris of continental origin was observed. Even though leaf detritus occurrence at site S2 was ∼5-fold higher compared to the other coastal site S1, it did not influence the total organic matter and its distribution among grain-size classes. Conversely, the specific organic content of dimensional fractions provided an effective assessment of detritus enrichment processes occurring at the two coastal sites. A group of brackish-originated crustaceans (i.e. the amphipods Gammarus insensibilis and G. aequicauda and the isopod Idotea baltica) was the main determinant of among-site multivariate differences in the vagile macrofauna; depositivorous ophiuroids accounted for the residual differences observed during the study period. The analysis of taxa abundance and individual body size indicated that in both site S1 and S3 macrodetritus advection to the benthic system corresponded with passive dispersal of brackish crustaceans, that provided a negligible contribution to the macrobenthic production. In contrast, in site S2 allochthonous inputs from marginal environments could have represented the key factor for the persistence of an authochthonous population of Gammarus insensibilis. The amphipod provided a considerable (19·4%) contribution to the total

  3. Parhyale darvishi, a new widely distributed amphipod species, in the Persian Gulf and the Gulf of Oman (Crustacea, Amphipoda, Hyalidae).

    PubMed

    Momtazi, Farzaneh; Maghsoudlou, Abdolvahab

    2016-01-01

    Parhyale darvishi sp. nov., is described. The new species is characterized by a naked posterior margin on the propodus of pereopods 5-7, a special arrangement of robust setae on the first male gnathopod and a lack of dense fine setae on the second antennae. Parhyale darvishi sp. nov. is distributed from the western coasts of the Persian Gulf to the eastern coasts of Gulf of Oman. PMID:27395677

  4. [Lipids in the amphipod Talorchestia margaritae (Amphipoda: Talitridae) and its relationship with the ecology of the species].

    PubMed

    López, Sandra; Díaz, Yusbelly; Noris, Karem; Cabrera, Aivle

    2010-09-01

    T. margaritae, an endemic species inhabiting Venezuelan coasts, plays an important ecological role in plant and animal decomposition. To understand this issue in some animal groups, especially small ones, lipid composition analysis has been an interesting tool to describe their trophic relationships and food preferences. In order to assess this and visualize the components of their diet, we determined the lipid composition differences between males and females and among age classes in this species. Two sandy beaches were selected: Mangle Quemao and Las Mercedes de Paparo, from which sand samples of known volume were collected at the supralittoral area in 2007. Organisms were separated by age and sex classes, and their size, weight, density, biomass, total lipids (TL), lipid classes and fatty acid markers present in their tissues were determined. The sizes were similar for all age classes between the two locations, while the weights were higher for Mangle Quemao. The TL and lipid classes showed similar proportions between sexes, age classes and locations (TL: 3-5%; Phospholipids: 20-30%; Glycolipids: <1%; sterols: 4%). On the other hand, Triglycerides (TAG) were higher in Mangle Quemao, which may be related to the difference between the weights of two locations. The most abundant fatty acid biomarkers in the two studied sites were 16:0 and 18:1(n-9); this last one is characteristic of a carnivorous diet. The other nine markers were identified with changes in their distribution in organisms at Mangle Quemao and between males and females of both populations. Based on observed fatty acids markers we can assume T. margaritae as a generalist carnivore. Those populations were influenced by available food; inducing differences in weight, TAG proportion and markers diversity. PMID:20737842

  5. WHAT IS CAUSING THE ACUTE AMPHIPOD TOXICITY OBSERVED IN FELD COLLECTED SAMPLES: AN INVESTIGATION USING EQUILIBRIUM PARTITIONING

    EPA Science Inventory

    Equilibrium partitioning (EqP) provides an independent method of deriving chemical concentrations in sediments that should be causally related to sediment toxicity. In this study, EqP was applied using a toxic unit model to determine whether concentrations of chemicals commonly m...

  6. CRITICAL BODY RESIDUES FOR FRESHWATER AND SALTWATER AMPHIPODS EXPOSED TO SEDIMENT CONTAINING A MIXTURE OF HIGH KOW PAHS

    EPA Science Inventory

    Sediments were spiked with a mixture of 13 high log Kow (5.4-6.8) PAH compounds to determine critical body residues (CBR) in Hyalella azteca and Leptocheirus plumulosus. Hyalella were exposed for 28 d in a intermittent flow test and for 10 d in a static test to compare PAH uptake...

  7. Avoidance of contaminated sediments by an amphipod (Melita plumulosa), A harpacticoid copepod (Nitocra spinipes), and a snail (Phallomedusa solida).

    PubMed

    Ward, Daniel J; Simpson, Stuart L; Jolley, Dianne F

    2013-03-01

    The distribution of contaminants is seldom homogeneous in aquatic systems. In the present study, the avoidance response of Melita plumulosa, Nitocra spinipes, and Phallomedusa solida when exposed to contaminated sediments was investigated. Test vessels were designed to allow the congruent placement of two sediments and assessment of the movement of organisms between the sediments. When exposed to reference sediment, each species dispersed evenly between test chambers regardless of differences in sediment particle size. In the presence of contaminated sediment, the magnitude and rate of avoidance varied. Avoidance assays showed that test species avoided contaminated sediment as early as 6, 6, and 24 h following exposure for N. spinipes, P. solida, and M. plumulosa, respectively. The 48-h avoidance response of M. plumulosa for nine contaminated sediments of varying toxicity showed that avoidance was generally greater for sediments which elicited greater 10-d lethality to this species. The study demonstrated that each of these species has the ability to respond to chemical cues in the environment to inhabit sediment that provides the best opportunity for survival. The avoidance response for each species indicates the potential for developing rapid screening methods to assess sediment quality. Evidence suggests that avoidance was related to sediment toxicity and that static 10-d toxicity methods are likely to overestimate toxicity for species, which would avoid contamination in heterogeneous field settings.

  8. Community structure and diversity of scavenging amphipods from bathyal to hadal depths in three South Pacific Trenches

    NASA Astrophysics Data System (ADS)

    Lacey, Nichola C.; Rowden, Ashley A.; Clark, Malcolm R.; Kilgallen, Niamh M.; Linley, Thomas; Mayor, Dan J.; Jamieson, Alan J.

    2016-05-01

    There are few biological datasets that span large bathymetric ranges with sufficient resolution to identify trends across the abyssal and hadal transition zone, particularly over multiple trenches. Here, scavenging Amphipoda were collected from three trenches in the South Pacific Ocean at bathyal to hadal depths. Diversity and community structure were examined from stations within the Kermadec Trench (1490-9908 m) and New Hebrides Trench (2000-6948 m) and additional data were included from the South Fiji Basin (4000 m) and Peru-Chile Trench (4602-8074 m). The hadal community structure of the Kermadec and New Hebrides trenches were distinct from the surrounding abyssal and bathyal depths and correlated to hydrostatic pressure and POC flux. Low POC flux in the New Hebrides Trench and South Fiji Basin best explained the dissimilarity in abyssal community structure from those of the disparate Kermadec and Peru-Chile trenches. POC flux also best explained patterns in hadal community structure with the Kermadec and New Hebrides Trench communities showing greater similarity to each other than to the eutrophic Peru-Chile Trench. Hydrostatic pressure was the strongest driver of intra-trench assemblage composition in all trench environments. A unimodal pattern of species diversity, peaking between 4000 and 5000 m, was best explained by hydrostatic pressure and temperature.

  9. SPATIAL VARIATION IN DENSITY, MEAN SIZE, AND PHYSIOLOGICAL CONDITION OF THE HOLARCTIC AMPHIPOD DIPOREIA SPP. IN LAKE MICHIGAN

    EPA Science Inventory

    We examined spatial patterns in population characteristics and physiological condition in Lake Michigan by collecting samples at up to 85 sites in late summer 1994 and 1995. Variables were examined relative to water depth and three lake regions: south, central and north. Most maj...

  10. Improving sediment-quality guidelines for nickel: development and application of predictive bioavailability models to assess chronic toxicity of nickel in freshwater sediments.

    PubMed

    Vangheluwe, Marnix L U; Verdonck, Frederik A M; Besser, John M; Brumbaugh, William G; Ingersoll, Christopher G; Schlekat, Christan E; Garman, Emily Rogevich

    2013-11-01

    Within the framework of European Union chemical legislations an extensive data set on the chronic toxicity of sediment nickel has been generated. In the initial phase of testing, tests were conducted with 8 taxa of benthic invertebrates in 2 nickel-spiked sediments, including 1 reasonable worst-case sediment with low concentrations of acid-volatile sulfide (AVS) and total organic carbon. The following species were tested: amphipods (Hyalella azteca, Gammarus pseudolimnaeus), mayflies (Hexagenia sp.), oligochaetes (Tubifex tubifex, Lumbriculus variegatus), mussels (Lampsilis siliquoidea), and midges (Chironomus dilutus, Chironomus riparius). In the second phase, tests were conducted with the most sensitive species in 6 additional spiked sediments, thus generating chronic toxicity data for a total of 8 nickel-spiked sediments. A species sensitivity distribution was elaborated based on 10% effective concentrations yielding a threshold value of 94 mg Ni/kg dry weight under reasonable worst-case conditions. Data from all sediments were used to model predictive bioavailability relationships between chronic toxicity thresholds (20% effective concentrations) and AVS and Fe, and these models were used to derive site-specific sediment-quality criteria. Normalization of toxicity values reduced the intersediment variability in toxicity values significantly for the amphipod species Hyalella azteca and G. pseudolimnaeus, but these relationships were less clearly defined for the mayfly Hexagenia sp. Application of the models to prevailing local conditions resulted in threshold values ranging from 126 mg to 281 mg Ni/kg dry weight, based on the AVS model, and 143 mg to 265 mg Ni/kg dry weight, based on the Fe model. PMID:23983116

  11. Improving sediment-quality guidelines for nickel: development and application of predictive bioavailability models to assess chronic toxicity of nickel in freshwater sediments

    USGS Publications Warehouse

    Vangheluwe, Marnix L. U.; Verdonck, Frederik A. M.; Besser, John M.; Brumbaugh, William G.; Ingersoll, Christopher G.; Schlekat, Christan E.; Rogevich Garman, Emily

    2013-01-01

    Within the framework of European Union chemical legislations an extensive data set on the chronic toxicity of sediment nickel has been generated. In the initial phase of testing, tests were conducted with 8 taxa of benthic invertebrates in 2 nickel-spiked sediments, including 1 reasonable worst-case sediment with low concentrations of acid-volatile sulfide (AVS) and total organic carbon. The following species were tested: amphipods (Hyalella azteca, Gammarus pseudolimnaeus), mayflies (Hexagenia sp.), oligochaetes (Tubifex tubifex, Lumbriculus variegatus), mussels (Lampsilis siliquoidea), and midges (Chironomus dilutus, Chironomus riparius). In the second phase, tests were conducted with the most sensitive species in 6 additional spiked sediments, thus generating chronic toxicity data for a total of 8 nickel-spiked sediments. A species sensitivity distribution was elaborated based on 10% effective concentrations yielding a threshold value of 94 mg Ni/kg dry weight under reasonable worst-case conditions. Data from all sediments were used to model predictive bioavailability relationships between chronic toxicity thresholds (20% effective concentrations) and AVS and Fe, and these models were used to derive site-specific sediment-quality criteria. Normalization of toxicity values reduced the intersediment variability in toxicity values significantly for the amphipod species Hyalella azteca and G. pseudolimnaeus, but these relationships were less clearly defined for the mayfly Hexagenia sp. Application of the models to prevailing local conditions resulted in threshold values ranging from 126 mg to 281 mg Ni/kg dry weight, based on the AVS model, and 143 mg to 265 mg Ni/kg dry weight, based on the Fe model

  12. The Role of Seagrass Traits in Mediating Zostera noltei Vulnerability to Mesograzers.

    PubMed

    Martínez-Crego, Begoña; Arteaga, Pedro; Tomas, Fiona; Santos, Rui

    2016-01-01

    Understanding how intra-specific differences in plant traits mediate vulnerability to herbivores of relevant habitat-forming plants is vital to attain a better knowledge on the drivers of the structure and functioning of ecosystems. Such studies, however, are rare in seagrass-mesograzer systems despite the increasingly recognized relevance of mesograzers as seagrass consumers. We investigated the role and potential trade-offs of multiple leaf traits in mediating the vulnerability of the seagrass Zostera noltei to different mesograzer species, the amphipod Gammarus insensibilis and the isopod Idotea chelipes. We worked with plants from two different meadows for which contrasting chemical and structural traits were expected based on previous information. We found that plants with high vulnerability to mesograzers (i.e. those preferred and subjected to higher rates of leaf area loss) had not only higher nitrogen content and lower C:N, fibre, and phenolics, but also tender and thinner leaves. No trade-offs between chemical and structural traits of the seagrass were detected, as they were positively correlated. When leaf physical structure was removed using agar-reconstituted food, amphipod preference towards high-susceptibility plants disappeared; thus indicating that structural rather than chemical traits mediated the feeding preference. Removal of plant structure reduced the size of isopod preference to less than half, indicating a stronger contribution of structural traits (> 50%) but combined with chemical/nutritional traits in mediating the preference. We then hypothesized that the high environmental nutrient levels recorded in the meadow exhibiting high susceptibility modulate the differences observed between meadows in seagrass traits. To test this hypothesis, we exposed low-vulnerability shoots to eutrophic nutrient levels in a 6-week enrichment experiment. Nutrient enrichment increased Z. noltei nitrogen content and lowered C:N, fibre, and phenolics, but had

  13. The Role of Seagrass Traits in Mediating Zostera noltei Vulnerability to Mesograzers.

    PubMed

    Martínez-Crego, Begoña; Arteaga, Pedro; Tomas, Fiona; Santos, Rui

    2016-01-01

    Understanding how intra-specific differences in plant traits mediate vulnerability to herbivores of relevant habitat-forming plants is vital to attain a better knowledge on the drivers of the structure and functioning of ecosystems. Such studies, however, are rare in seagrass-mesograzer systems despite the increasingly recognized relevance of mesograzers as seagrass consumers. We investigated the role and potential trade-offs of multiple leaf traits in mediating the vulnerability of the seagrass Zostera noltei to different mesograzer species, the amphipod Gammarus insensibilis and the isopod Idotea chelipes. We worked with plants from two different meadows for which contrasting chemical and structural traits were expected based on previous information. We found that plants with high vulnerability to mesograzers (i.e. those preferred and subjected to higher rates of leaf area loss) had not only higher nitrogen content and lower C:N, fibre, and phenolics, but also tender and thinner leaves. No trade-offs between chemical and structural traits of the seagrass were detected, as they were positively correlated. When leaf physical structure was removed using agar-reconstituted food, amphipod preference towards high-susceptibility plants disappeared; thus indicating that structural rather than chemical traits mediated the feeding preference. Removal of plant structure reduced the size of isopod preference to less than half, indicating a stronger contribution of structural traits (> 50%) but combined with chemical/nutritional traits in mediating the preference. We then hypothesized that the high environmental nutrient levels recorded in the meadow exhibiting high susceptibility modulate the differences observed between meadows in seagrass traits. To test this hypothesis, we exposed low-vulnerability shoots to eutrophic nutrient levels in a 6-week enrichment experiment. Nutrient enrichment increased Z. noltei nitrogen content and lowered C:N, fibre, and phenolics, but had

  14. The Role of Seagrass Traits in Mediating Zostera noltei Vulnerability to Mesograzers

    PubMed Central

    Martínez-Crego, Begoña; Arteaga, Pedro; Tomas, Fiona; Santos, Rui

    2016-01-01

    Understanding how intra-specific differences in plant traits mediate vulnerability to herbivores of relevant habitat-forming plants is vital to attain a better knowledge on the drivers of the structure and functioning of ecosystems. Such studies, however, are rare in seagrass-mesograzer systems despite the increasingly recognized relevance of mesograzers as seagrass consumers. We investigated the role and potential trade-offs of multiple leaf traits in mediating the vulnerability of the seagrass Zostera noltei to different mesograzer species, the amphipod Gammarus insensibilis and the isopod Idotea chelipes. We worked with plants from two different meadows for which contrasting chemical and structural traits were expected based on previous information. We found that plants with high vulnerability to mesograzers (i.e. those preferred and subjected to higher rates of leaf area loss) had not only higher nitrogen content and lower C:N, fibre, and phenolics, but also tender and thinner leaves. No trade-offs between chemical and structural traits of the seagrass were detected, as they were positively correlated. When leaf physical structure was removed using agar-reconstituted food, amphipod preference towards high-susceptibility plants disappeared; thus indicating that structural rather than chemical traits mediated the feeding preference. Removal of plant structure reduced the size of isopod preference to less than half, indicating a stronger contribution of structural traits (> 50%) but combined with chemical/nutritional traits in mediating the preference. We then hypothesized that the high environmental nutrient levels recorded in the meadow exhibiting high susceptibility modulate the differences observed between meadows in seagrass traits. To test this hypothesis, we exposed low-vulnerability shoots to eutrophic nutrient levels in a 6-week enrichment experiment. Nutrient enrichment increased Z. noltei nitrogen content and lowered C:N, fibre, and phenolics, but had

  15. Improving sediment-quality guidelines for nickel: development and application of predictive bioavailability models to assess chronic toxicity of nickel in freshwater sediments.

    PubMed

    Vangheluwe, Marnix L U; Verdonck, Frederik A M; Besser, John M; Brumbaugh, William G; Ingersoll, Christopher G; Schlekat, Christan E; Garman, Emily Rogevich

    2013-11-01

    Within the framework of European Union chemical legislations an extensive data set on the chronic toxicity of sediment nickel has been generated. In the initial phase of testing, tests were conducted with 8 taxa of benthic invertebrates in 2 nickel-spiked sediments, including 1 reasonable worst-case sediment with low concentrations of acid-volatile sulfide (AVS) and total organic carbon. The following species were tested: amphipods (Hyalella azteca, Gammarus pseudolimnaeus), mayflies (Hexagenia sp.), oligochaetes (Tubifex tubifex, Lumbriculus variegatus), mussels (Lampsilis siliquoidea), and midges (Chironomus dilutus, Chironomus riparius). In the second phase, tests were conducted with the most sensitive species in 6 additional spiked sediments, thus generating chronic toxicity data for a total of 8 nickel-spiked sediments. A species sensitivity distribution was elaborated based on 10% effective concentrations yielding a threshold value of 94 mg Ni/kg dry weight under reasonable worst-case conditions. Data from all sediments were used to model predictive bioavailability relationships between chronic toxicity thresholds (20% effective concentrations) and AVS and Fe, and these models were used to derive site-specific sediment-quality criteria. Normalization of toxicity values reduced the intersediment variability in toxicity values significantly for the amphipod species Hyalella azteca and G. pseudolimnaeus, but these relationships were less clearly defined for the mayfly Hexagenia sp. Application of the models to prevailing local conditions resulted in threshold values ranging from 126 mg to 281 mg Ni/kg dry weight, based on the AVS model, and 143 mg to 265 mg Ni/kg dry weight, based on the Fe model.

  16. Effect of submersed aquatic macrophytes on resource partitioning in yearling rock bass (Ambloplites rupestris) and pumpkinseeds (Lepomis gibbosus) in Lake St. Clair

    USGS Publications Warehouse

    French, John R. P., III

    1988-01-01

    Yearling rock bass (Ambloplites rupestris), pumpkinseeds (Lepomis gibbosus), macroinvertebrates, and submersed aquatic plants were sampled at 2- or 3-week intervals from June to October 1979 in a shallow, heavily vegetated embayment in Lake St. Clair to determine whether seasonal changes in plant canopy and plant taxonomic composition affected resource partitioning in these two fish species. In both species, numbers of prey and gut volumes increased with increasing plant canopy until the plant canopy reached a seasonal maximum in mid-summer. Rock bass consumed fewer, larger prey than pumpkinseeds while large Caenidae-Trichoptera-Coenagrionidae, the prey group most preferred by rock bass, was available. Pumpkinseeds ate smaller amphipods, gastropods, and chironomid-lepidopterans that were more abundant numerically than Caenidae-Trichoptera-Coenagrionidae. After mid-summer, the plant canopy declined slowly to one-half of the maximum value, but built-up densities ofHyalella azteca, gastropods, and chironomid-lepidopterans kept availability of prey high throughout late summer. Rock bass shifted to Gammarus, gastropods, and chironomid-lepidopterans as large Caenidae-Trichoptera-Coenagrionidae became scarce. Pumpkinseeds ate more prey in the late season and displayed no prey preference. Their gut volumes peaked in September. Apparently, increasing combined canopy of bushy plants and Heteranthera dubia hindered the foraging of rock bass more than that of pumpkinseeds and caused resource partitioning in the two species.

  17. Effects of the Veterinary Pharmaceutical Ivermectin in Indoor Aquatic Microcosms

    PubMed Central

    Boonstra, Harry; Reichman, Erik P.

    2010-01-01

    The effects of the parasiticide ivermectin were assessed in plankton-dominated indoor microcosms. Ivermectin was applied once at concentrations of 30, 100, 300, 1000, 3000, and 10,000 ng/l. The half-life (dissipation time 50%; DT50) of ivermectin in the water phase ranged from 1.1 to 8.3 days. The lowest NOECcommunity that could be derived on an isolated sampling from the microcosm study by means of multivariate techniques was 100 ng/l. The most sensitive species in the microcosm study were the cladocerans Ceriodaphnia sp. (no observed effect concentration, NOEC = 30 ng/l) and Chydorus sphaericus (NOEC = 100 ng/l). The amphipod Gammarus pulex was less sensitive to ivermectin, showing consistent statistically significant reductions at the 1000-ng/l treatment level. Copepoda taxa decreased directly after application of ivermectin in the highest treatment but had already recovered at day 20 posttreatment. Indirect effects (e.g., increase of rotifers, increased primary production) were observed at the highest treatment level starting only on day 13 of the exposure phase. Cladocera showed the highest sensitivity to ivermectin in both standard laboratory toxicity tests as well as in the microcosm study. This study demonstrates that simple plankton-dominated test systems for assessing the effects of ivermectin can produce results similar to those obtained with large complex outdoor systems. PMID:20422169

  18. Eaten alive: cannibalism is enhanced by parasites.

    PubMed

    Bunke, Mandy; Alexander, Mhairi E; Dick, Jaimie T A; Hatcher, Melanie J; Paterson, Rachel; Dunn, Alison M

    2015-03-01

    Cannibalism is ubiquitous in nature and especially pervasive in consumers with stage-specific resource utilization in resource-limited environments. Cannibalism is thus influential in the structure and functioning of biological communities. Parasites are also pervasive in nature and, we hypothesize, might affect cannibalism since infection can alter host foraging behaviour. We investigated the effects of a common parasite, the microsporidian Pleistophora mulleri, on the cannibalism rate of its host, the freshwater amphipod Gammarus duebeni celticus. Parasitic infection increased the rate of cannibalism by adults towards uninfected juvenile conspecifics, as measured by adult functional responses, that is, the rate of resource uptake as a function of resource density. This may reflect the increased metabolic requirements of the host as driven by the parasite. Furthermore, when presented with a choice, uninfected adults preferred to cannibalize uninfected rather than infected juvenile conspecifics, probably reflecting selection pressure to avoid the risk of parasite acquisition. By contrast, infected adults were indiscriminate with respect to infection status of their victims, probably owing to metabolic costs of infection and the lack of risk as the cannibals were already infected. Thus parasitism, by enhancing cannibalism rates, may have previously unrecognized effects on stage structure and population dynamics for cannibalistic species and may also act as a selective pressure leading to changes in resource use. PMID:26064614

  19. The relative importance of diet-related and waterborne effects of copper for a leaf-shredding invertebrate.

    PubMed

    Zubrod, J P; Englert, D; Rosenfeldt, R R; Wolfram, J; Lüderwald, S; Wallace, D; Schnetzer, N; Schulz, R; Bundschuh, M

    2015-10-01

    Copper (Cu) exposure can increase leaf-associated fungal biomass, an important food component for leaf-shredding macroinvertebrates. To test if this positive nutritional effect supports the physiological fitness of these animals and to assess its importance compared to waterborne toxicity, we performed a 24-day-bioassay in combination with a 2×2 factorial design using the amphipod shredder Gammarus fossarum and a field-relevant Cu concentration of 25 μg/L (n = 65). Waterborne toxicity was negligible, while gammarids fed leaves exposed to Cu during microbial colonization exhibited a near-significant impairment in growth (∼30%) and a significantly reduced lipid content (∼20%). These effects appear to be governed by dietary uptake of Cu, which accumulated in leaves as well as gammarids and likely overrode the positive nutritional effect of the increased fungal biomass. Our results suggest that for adsorptive freshwater contaminants dietary uptake should be evaluated already during the registration process to safeguard the integrity of detritus-based ecosystems.

  20. Ecological effects of rubble-mound breakwater construction and channel dredging at West Harbor, Ohio (western Lake Erie)

    USGS Publications Warehouse

    Manny, Bruce A.; Schloesser, Donald W.; Brown, Charles L.; French, John R. P.

    1985-01-01

    The investigation reported herein indicated that breakwater construction and associated channel dredging activities by the US Army Corps of Engineers in western Lake Erie at the entrance to West Harbor (Ohio) had no detectable adverse impacts on the distributions or abundances of macrozoobenthos and fishes. Rather, increases were noted in the number of fish eggs and larvae and in the density and biomass of periphyton and macrozoobenthos on and near the breakwaters. The area also served as a nursery ground for 20 species of fishes both during and after construction and dredging activities. Colonization of the breakwaters by periphyton, primarily a green alga (Cladophora glomerata), diatoms (Gomphonema parvulum), and a bluegreen alga (Oscillatoria tenuis), and by macrozoobenthos, primarily worms (Oligochaeta), amphipods (Gammarus spp.), and midge larvae (Chironomidae), was rapid and extensive, indicating that the breakwaters provided new, favorable habitat for primary and secondary producer organisms. Marked adverse changes in water quality, especially reduced dissolved oxygen concentrations (25 mg/l), occurred around the entrance to West Harbor in 1983 following cessation of construction and dredging activities. These water quality changes, however, could not be ascribed with certainty to construction and dredging activities at West Harbor. Construction of additional breakwaters in the study area at that time by the State of Ohio served to confound determination of the responsible causal factors.

  1. Effects of Fucus vesiculosus covering intertidal mussel beds in the Wadden Sea

    NASA Astrophysics Data System (ADS)

    Albrecht, A.; Reise, K.

    1994-06-01

    The brown alga Fucus vesiculosus forma mytili (Nienburg) Nienhuis covered about 70% of mussel bed ( Mytilus edulis) surface area in the lower intertidal zone of Königshafen, a sheltered sandy bay near the island of Sylt in the North Sea. Mean biomass in dense patches was 584 g ash-free dry weight m-2 in summer. On experimental mussel beds, fucoid cover enhanced mud accumulation and decreased mussel density. The position of mussels underneath algal canopy was mainly endobenthic (87% of mussels with >1/3 of shell sunk into mud). In the absence of fucoids, mussels generated epibenthic garlands (81% of mussels with <1/3 of shell buried in mud). Mussel density underneath fucoid cover was 40 to 73% of mussel density without algae. On natural beds, barnacles (Balanidae), periwinkles ( Littorina littorea) and crabs (particularly juveniles of Carcinus maenas) were significantly less abundant in the presence of fucoids, presumably because most of the mussels were covered with sediment, whereas in the absence of fucoids, epibenthic mussel clumps provided substratum as well as interstitial hiding places. The endobenthic macrofauna showed little difference between covered and uncovered mussel beds. On the other hand, grazing herbivores — the flat periwinkle Littorina mariae, the isopod Jaera albifrons and the amphipods Gammarus spp. — were more abundant at equivalent sites with fucoid cover. The patchy growth of Fucus vesiculosus on mussel beds in the intertidal Wadden Sea affects mussels and their epibionts negatively, but supports various herbivores and increases overall benthic diversity.

  2. Eaten alive: cannibalism is enhanced by parasites

    PubMed Central

    Bunke, Mandy; Alexander, Mhairi E.; Dick, Jaimie T. A.; Hatcher, Melanie J.; Paterson, Rachel; Dunn, Alison M.

    2015-01-01

    Cannibalism is ubiquitous in nature and especially pervasive in consumers with stage-specific resource utilization in resource-limited environments. Cannibalism is thus influential in the structure and functioning of biological communities. Parasites are also pervasive in nature and, we hypothesize, might affect cannibalism since infection can alter host foraging behaviour. We investigated the effects of a common parasite, the microsporidian Pleistophora mulleri, on the cannibalism rate of its host, the freshwater amphipod Gammarus duebeni celticus. Parasitic infection increased the rate of cannibalism by adults towards uninfected juvenile conspecifics, as measured by adult functional responses, that is, the rate of resource uptake as a function of resource density. This may reflect the increased metabolic requirements of the host as driven by the parasite. Furthermore, when presented with a choice, uninfected adults preferred to cannibalize uninfected rather than infected juvenile conspecifics, probably reflecting selection pressure to avoid the risk of parasite acquisition. By contrast, infected adults were indiscriminate with respect to infection status of their victims, probably owing to metabolic costs of infection and the lack of risk as the cannibals were already infected. Thus parasitism, by enhancing cannibalism rates, may have previously unrecognized effects on stage structure and population dynamics for cannibalistic species and may also act as a selective pressure leading to changes in resource use. PMID:26064614

  3. Trophic transfer of pyrene metabolites between aquatic invertebrates.

    PubMed

    Carrasco Navarro, V; Leppänen, M T; Kukkonen, J V K; Godoy Olmos, S

    2013-02-01

    The trophic transfer of pyrene metabolites was studied using Gammarus setosus as a predator and the invertebrates Lumbriculus variegatus and Chironomus riparius as prey. The results obtained by liquid scintillation counting confirmed that the pyrene metabolites produced by the aquatic invertebrates L. variegatus and C. riparius were transferred to G. setosus through the diet. More detailed analyses by liquid chromatography discovered that two of the metabolites produced by C. riparius appeared in the chromatograms of G. setosus tissue extracts, proving their trophic transfer. These metabolites were not present in chromatograms of G. setosus exclusively exposed to pyrene. The present study supports the trophic transfer of PAH metabolites between benthic macroinvertebrates and common species of an arctic amphipod. As some PAH metabolites are more toxic than the parent compounds, the present study raises concerns about the consequences of their trophic transfer and the fate and effects of PAHs in natural environments. PMID:23202283

  4. Comparison of the variable loop regions of myosin heavy chain genes from Antarctic and temperate isopods.

    PubMed

    Holmes, J M; Whiteley, N M; Magnay, J L; El Haj, A J

    2002-03-01

    The evolutionary adaptations of functional genes to life at low temperatures are not well characterised in marine and fresh water invertebrates. Temperature has been shown to affect the functional characteristics of fish muscles, with changes in the velocity of shortening and ATPase activity being associated with myosin heavy chain (MyHC) isoform composition and the structure of the surface loop regions. Two PCR products spanning loops 1 and 2 of a MyHC gene from an Antarctic isopod (Glyptonotus antarcticus) were sequenced and compared with those of a temperate isopod (Idotea resecata), slow and fast fibres from lobster (Homarus gammarus) and a cold water amphipod (Eulimnogammarus verrucosus), revealing specific differences between the species, possibly related to fibre type and habitat temperature. The loop 2 region from G. antarcticus myosin was cloned and used for Northern analysis of total RNA from the other species. The cloned myosin cDNA hybridised specifically to a 6.6-kb transcript, in G. antarcticus muscle. In contrast, cDNA probes for lobster slow myosin and actin hybridised to muscle RNA from all species, demonstrating that a distinct MyHC isoform is expressed in the Antarctic isopod, as opposed to the temperate species. The inter- and intra-specific sequence differences in loop 2 region suggest that this may be a site for muscle adaptation to enable function at the low temperatures found in the Southern Ocean. PMID:11959017

  5. Altered host behaviour and brain serotonergic activity caused by acanthocephalans: evidence for specificity

    PubMed Central

    Tain, Luke; Perrot-Minnot, Marie-Jeanne; Cézilly, Frank

    2006-01-01

    Manipulative parasites can alter the phenotype of intermediate hosts in various ways. However, it is unclear whether such changes are just by-products of infection or adaptive and enhance transmission to the final host. Here, we show that the alteration of serotonergic activity is functionally linked to the alteration of specific behaviour in the amphipod Gammarus pulex infected with acanthocephalan parasites. Pomphorhynchus laevis and, to a lesser extent, Pomphorhynchus tereticollis altered phototactism, but not geotactism, in G. pulex, whereas the reverse was true for Polymorphus minutus. Serotonin (5-hydroxytryptamine, 5-HT) injected to uninfected G. pulex mimicked the altered phototactism, but had no effect on geotactism. Photophilic G. pulex infected with P. laevis or P. tereticollis showed a 40% increase in brain 5-HT immunoreactivity compared to photophobic, uninfected individuals. In contrast, brain 5-HT immunoreactivity did not differ between P. minutus-infected and uninfected G. pulex. Finally, brain 5-HT immunoreactivity differed significantly among P. tereticollis-infected individuals in accordance with their degree of manipulation. Our results demonstrate that altered 5-HT activity is not the mere consequence of infection by acanthocephalans but is specifically linked to the disruption of host photophobic behaviour, whereas the alteration of other behaviours such as geotactism may rely on distinct physiological routes. PMID:17015346

  6. Effects of stream acidification on fungal biomass in decaying beech leaves and leaf palatability.

    PubMed

    Dangles, O; Chauvet, E

    2003-02-01

    We examined the effect of surface water acidification on rates of decomposition, ergosterol concentrations (as a measure of fungal biomass), and palatability to shredders of common beech leaves (Fagus sylvatica L.) in five mountain streams (pH 4.7-7.1). Leaf decomposition was significantly faster in the circumneutral streams (pH 6.4-7.1; k > or = 0.00175 d(-1)), when compared to acidic streams (pH 4.7-4.9; k < or = 0.00100 d(-1)). Fungal biomass showed no particular trend along the acidification gradient except that it peaked earlier in the stream closest to neutrality. Leaf palatability, measured as the feeding activity of the leaf-shredding amphipod Gammarus fossarum Koch, varied with the exposure time in the streams. Except for the higher palatability of leaves exposed during 6 weeks at the highest pH, patterns among streams were mostly similar. These results suggest that reduced processing rates in the most acidic streams were not related to differences in fungal biomass associated with decomposing leaves and that microbial conditioning was only slightly delayed by acidification. Possible effects of low pH and related variables (Ca, Al) on microbial decomposition and detritivorous macroinvertebrates are discussed to clarify the inhibition of beech leaf decomposition in the studied systems.

  7. Effect of sulfate concentration on acute toxicity of selenite and selenate to invertebrates and fish. Final report

    SciTech Connect

    McIntyre, D.O.; McCauley, D.J.; McCool, P.; Winkler, N.; DeGraeve, M.

    1998-12-01

    The effect of sulfate concentration on the acute toxicity of selenite (Se IV) and selenate (Se VI) to freshwater organisms was evaluated using toxicity test data generated from this study and toxicity data obtained from the open literature. The acute toxicity of Se IV and Se VI to fathead minnows and two amphipod species, Gammarus pseudolimnaeus and Hyalella azteca, were determined in four different sulfate concentrations. The newly generated toxicity data combined with the data obtained from the literature were evaluated using analysis of covariance to determine if there was a significant relationship between acute toxicity and sulfate concentration. The analysis of the Se IV data indicated that there was not a significant relationship between the acute toxicity of Se IV and sulfate concentration. A significant relationship was found between the acute toxicity of Se VI to freshwater organisms and sulfate concentration. Statistically significant slopes describing the relationship between Se VI toxicity and sulfate concentration were determined for individual species and for the combined data. A sulfate-based equation was constructed using the pooled slope to modify the criterion maximum concentration (CMC) for selenate: CMC = e{sup [0.4259(ln[sulfate]) + 4.6305]}.

  8. Effects of the ``Amoco Cadiz '' oil spill on an eelgrass community at roscoff (france) with special reference to the mobile benthic fauna

    NASA Astrophysics Data System (ADS)

    den Hartog, C.; Jacobs, R. P. W. M.

    1980-03-01

    In October 1977 an investigation was initiated of the qualitative and quantitative composition of the fauna of the eelgrass ( Zostera marina) beds at Roscoff. Samples were taken in 2 seagrass beds at different tidal levels in order to follow numerical changes in the course of the year. In March 1978 the area of study was struck by the oil slick of the tanker “Amoco Cadiz ”. For this reason sampling has been continued at the same frequency. The tabulated results show clearly that the oil slick had a profound but selective influence on the various animal groups; some of them disappeared while others were apparently unaffected. Rapid recovery of some species has taken place, but re-establishment of other species, particularly the filter feeders has not been observed. The very diverse amphipod fauna has disappeared, and has been replaced by a population of Pherusa fucicola and Gammarus locusta; the latter was absent in the year before the oil disaster took place.

  9. Comparative study of lead accumulation in different organs of perch (Perca fluviatilis) and its intestinal parasite Acanthocephalus lucii

    SciTech Connect

    Sures, B.; Taraschewski, H.; Jackwerth, E. )

    1994-02-01

    Lead is known as an important aquatic contaminant with different toxic effects on various organisms. Considerable data are available on lead in aquatic ecosystems including water, sediments, fishes and invertebrates. Until now, no quantitative investigations have been published comparing the heavy metal (Pb, Cd, Hg) content in parasites with that in their final or intermediate hosts, although such parasites are very prevalent in many fish and invertebrate populations. Only Brown and Pascoe (1989) reported that the amphipod Gammarus pulex parasitized with the acanthocephalan Pomphorhynchus laevis was two or three times more sensitive to cadmium at low exposure concentrations (2.1 [mu]g 1[sup [minus]1]) than uninfected conspecifics. The objective of the present study was to combine trace analytical and parasitological methods to investigate lead concentrations in different tissues (muscle, liver and intestine) of perch (Perca fluviatilis) and in the palaeacanthocephalan Acanthocephalus lucii parasitizing the intestine of these fishes. The fish were caught in the river Ruhr which drains the densely populated and industrialized Ruhr-district. 14 refs., 2 tabs.

  10. The distribution of the amphipod Corophium arenarium in the Dutch Wadden Sea: relationships with sediment composition and the presence of cockles and lugworms

    NASA Astrophysics Data System (ADS)

    Flach, E. C.

    On the tidal flats in the Dutch Wadden Sea Corophium volutator is a dominant species of the upper intertidal zone; the closely related Corophium arenarium is usually found in the lower zone, but only in low densities (a few hundreds per m 2). A survey in the Dutch Wadden Sea showed that this zonation pattern was only present when a muddy sediment was found in the upper zone and a sandy in the lower zone. C. arenarium was restricted to sandy sediments, C. volutator to muddy sediments. Where a sandy sediment was found in the upper intertidal zone, C. arenarium locally occurred in relatively high densities (a few thousands per m 2). An aquarium experiment showed that C. arenarium actively avoided muddy sediments. Field experiments were carried out to study the influence of other macrozoobenthic species (known to affect the related C. volutator) on the abundance of C. arenarium. Within large defaunated areas small plots were stocked with different densities of the lugworm Arenicola marina and the cockle Cerastoderma edule. In small plots within a natural benthic community densities of these species were also augmented or (in A. marina) reduced. Strongly negative density-dependent effects of both A. marina and C. edule were found on the abundance of C. arenarium. In the natural situation, its densities showed A. marina to be the most important factor in determining the abundance of C. arenarium. In particular the removal of lugworms caused a strong increase in C. arenarium densities. These results agreed with the distribution of these species along a transect perpendicular to the shore of Schiermonnikoog, where a significant negative correlation was found between the densities of A. marina and C. arenarium. Aquarium experiments showed that the negative effect of cockles and lugworms must be due to migration rather than mortality in C. arenarium.

  11. Leucothoe kawesqari, a new amphipod from Bernardo O'Higgins National Park (Chile), with remarks on the genus in the Magellan Region (Crustacea, Peracarida).

    PubMed

    Esquete, Patricia; Aldea, Cristian

    2015-01-01

    Although the genus Leucothoe has been reported repeatedly in the Magellan Region, the citations in the Channels and Fjords Ecoregion were either unidentified or attributed to the previously considered cosmopolitan Leucothoe spinicarpa. In this work, Leucothoe kawesqari sp. n. is described, which can be distinguished from other species of the genus in the Southern Ocean by having eyes present, epimeral plates with no setae, anterior coxae not acutely produced or excavate, coxa 5 slightly bilobed, accessory flagellum present, mandibular palp article 3 shorter than ½ article 2, pereopods 5-7 basis expanded, ovoid, posterior margin weakly crenulate and telson apex irregularly truncated. The new species was found in hard substrates, both unvegetated and with macroalgae, mainly in kelp forest of Macrocystis pyrifera. PMID:26798246

  12. Effects of contaminated St. Lucie River saltwater sediments on an amphipod (Ampelisca abdita) and a hard-shell clam (Mercenaria mercenaria).

    PubMed

    Hoang, Tham C; Rand, Gary M

    2014-08-01

    The St. Lucie estuary (SLE) ecosystem in South Florida has been shown to be contaminated with metals and pesticides. Our earlier studies also showed that aquatic organisms, especially benthic species in the SLE ecosystem, might be potentially at high risk from copper (Cu) exposure. The objectives of this study were to conduct studies with separate groups of organisms exposed to seven field-collected sediment samples from the St. Lucie River according to standard procedures to evaluate toxicity and tissue concentrations of Cu and zinc (Zn). Short term and longer term whole sediment acute toxicity studies were performed with Ampelisca abdita and Mercenaria mercenaria. Analysis of sediment chemical characteristics showed that Cu and Zn are of most concern because their concentrations in 86 % of the sediments were higher than the threshold effect concentrations for Florida sediment quality criteria and the National Oceanic and Atmospheric Administration Screening Quick Reference Tables (SQuiRTs) sediment values. There was no significant effect on survival of the tested organisms. However, increased Cu and Zn concentrations in the test organisms were found. Dry weight of the tested organisms was also inversely related to Cu and Zn concentrations in sediments and organisms. The effects on organism weight and Cu and Zn uptake raise concerns about the organism population dynamics of the ecosystem because benthic organisms are primary food sources in the SLE system and are continuously exposed to Cu- and Zn-contaminated sediments throughout their life cycle. The results of the present study also indicate that Cu and Zn exposures by way of sediment ingestion are important routes of exposure.

  13. No Small Matter? An Increase of 30 Trillion Amphipods (plus or minus a few) in Lake Superior between 1973 and 2005

    EPA Science Inventory

    We compared a lakewide biological sampling in 2005 with the other lakewide biological sampling of Lake Superior in 1973...Lakewide, there were 40 trillion Diporeia in 2005, an increase of approx. 30 trillion compared with 1973. The open questions: what caused this apparen...

  14. Redescription of two subterranean amphipods Niphargus molnari Méhely, 1927 and Niphargus gebhardti Schellenberg, 1934 (Amphipoda, Niphargidae) and their phylogenetic position

    PubMed Central

    Angyal, Dorottya; Balázs, Gergely; Zakšek, Valerija; Krízsik, Virág; Fišer, Cene

    2015-01-01

    Abstract A detailed redescription of two endemic, cave-dwelling niphargid species of the Hungarian Mecsek Mts., Niphargus molnari Méhely, 1927 and Niphargus gebhardti Schellenberg, 1934 is given based on newly collected material. Morphology was studied under light microscopy and with scanning electon microscopy. Morphological descriptions are complemented with mitochondrial cytochrome c oxidase subunit I (COI) sequences as barcodes for both species and with notes on their ecology. Using three independent molecular markers we showed that Niphargus gebhardti belongs to the clade distributed between Central and Eastern Europe, whereas phylogenetic relationship of Niphargus molnari to the rest of Niphargus species is not clear. The two species from the Mecsek Mts. are phylogenetically not closely related. Both species need to be treated as vulnerable according to IUCN Red List of Threatened Species. PMID:26175603

  15. Leucothoe kawesqari, a new amphipod from Bernardo O'Higgins National Park (Chile), with remarks on the genus in the Magellan Region (Crustacea, Peracarida).

    PubMed

    Esquete, Patricia; Aldea, Cristian

    2015-01-01

    Although the genus Leucothoe has been reported repeatedly in the Magellan Region, the citations in the Channels and Fjords Ecoregion were either unidentified or attributed to the previously considered cosmopolitan Leucothoe spinicarpa. In this work, Leucothoe kawesqari sp. n. is described, which can be distinguished from other species of the genus in the Southern Ocean by having eyes present, epimeral plates with no setae, anterior coxae not acutely produced or excavate, coxa 5 slightly bilobed, accessory flagellum present, mandibular palp article 3 shorter than ½ article 2, pereopods 5-7 basis expanded, ovoid, posterior margin weakly crenulate and telson apex irregularly truncated. The new species was found in hard substrates, both unvegetated and with macroalgae, mainly in kelp forest of Macrocystis pyrifera.

  16. Sediment contamination of residential streams in the metropolitan kansas city area, USA: Part II. whole-sediment toxicity to the amphipod hyalella azteca

    USGS Publications Warehouse

    Tao, J.; Ingersoll, C.G.; Kemble, N.E.; Dias, J.R.; Murowchick, J.B.; Welker, G.; Huggins, D.

    2010-01-01

    This is the second part of a study that evaluates the influence of nonpoint sources on the sediment quality of five adjacent streams within the metropolitan Kansas City area, central United States. Physical, chemical, and toxicity data (Hyalella azteca 28-day whole-sediment toxicity test) for 29 samples collected in 2003 were used for this evaluation, and the potential causes for the toxic effects were explored. The sediments exhibited a low to moderate toxicity, with five samples identified as toxic to H. azteca. Metals did not likely cause the toxicity based on low concentrations of metals in the pore water and elevated concentrations of acid volatile sulfide in the sediments. Although individual polycyclic aromatic hydrocarbons (PAHs) frequently exceeded effect-based sediment quality guidelines [probable effect concentrations (PECs)], only four of the samples had a PEC quotient (PEC-Q) for total PAHs over 1.0 and only one of these four samples was identified as toxic. For the mean PEC-Q for organochlorine compounds (chlordane, dieldrin, sum DDEs), 4 of the 12 samples with a mean PEC-Q above 1.0 were toxic and 4 of the 8 samples with a mean PEC-Q above 3.0 were toxic. Additionally, four of eight samples were toxic, with a mean PEC-Q above 1.0 based on metals, PAHs, polychlorinated biphenyls (PCBs), and organochlorine pesticides. The increase in the incidence of toxicity with the increase in the mean PEC-Q based on organochlorine pesticides or based on metals, PAHs, PCBs, and organochlorine pesticides suggests that organochlorine pesticides might have contributed to the observed toxicity and that the use of a mean PEC-Q, rather than PEC-Qs for individual compounds, might be more informative in predicting toxic effects. Our study shows that stream sediments subject to predominant nonpoint sources contamination can be toxic and that many factors, including analysis of a full suite of PAHs and pesticides of both past and present urban applications and the origins of these organic compounds, are important to identify the causes of toxicity. ?? 2010 Springer Science+Business Media, LLC.

  17. Geographic range and structure of cryptic genetic diversity among Pacific North American populations of the non-nat