The trophic position of the alien crab Rhithropanopeus harrisii (crustacea decapoda panopeidae) in the Taman Bay, Sea of Azov community

NASA Astrophysics Data System (ADS)

Zalota, A. K.; Kolyuchkina, G. A.; Tiunov, A. V.; Biriukova, S. V.; Spiridonov, V. A.

2017-03-01

This work concerns the trophic web positioning of the alien crab Rhithropanopeus harrisii and other common marine invertebrate species and fishes in the benthic ecosystem of the shallows of Taman Bay, Sea of Azov. The base of the trophic web in this system is composed of phytoplankton, macrophytes (algae and marine grasses), and reeds that use atmospheric carbon for photosynthesis. Analysis of the isotopic composition of nitrogen and carbon has shown that although marine grasses are dominating primary producers in the shallows of the bay, primary consumers (such as Cerastoderma glaucum, Porifera gen. sp., Gammarus aequicauda, Deshayesorchestia deshayesii and Idotea balthica) only partially use this organic source; instead, they use a combination of different sources of primary production. It has been shown that the food source of the alien crab is primarily of animal origin. In Taman Bay, R. harrisii is on the same trophic level as other carnivores/scavengers: benthic fishes Syngnathus nigrolineatus, Gobius spp. and native crab Pilumnus hirtellus and shrimp Palaemon adspersus.

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. Copyright © 2015 Elsevier Inc. All rights reserved.

Sexual selection and population divergence II. Divergence in different sexual traits and signal modalities in field crickets (Teleogryllus oceanicus).

PubMed

Pascoal, Sonia; Mendrok, Magdalena; Wilson, Alastair J; Hunt, John; Bailey, Nathan W

2017-06-01

Sexual selection can target many different types of traits. However, the relative influence of different sexually selected traits during evolutionary divergence is poorly understood. We used the field cricket Teleogryllus oceanicus to quantify and compare how five traits from each of three sexual signal modalities and components diverge among allopatric populations: male advertisement song, cuticular hydrocarbon (CHC) profiles and forewing morphology. Population divergence was unexpectedly consistent: we estimated the among-population (genetic) variance-covariance matrix, D, for all 15 traits, and D max explained nearly two-thirds of its variation. CHC and wing traits were most tightly integrated, whereas song varied more independently. We modeled the dependence of among-population trait divergence on genetic distance estimated from neutral markers to test for signatures of selection versus neutral divergence. For all three sexual trait types, phenotypic variation among populations was largely explained by a neutral model of divergence. Our findings illustrate how phenotypic integration across different types of sexual traits might impose constraints on the evolution of mating isolation and divergence via sexual selection. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Responses of the brackish-water amphipod Gammarus duebeni (crustacea) to saline sewage

NASA Astrophysics Data System (ADS)

Jones, M. B.; Johnson, I.

Soon after the openiing of the Looe sewage treatment works (Cornwall, southwest England) in 1973, it became colonized by the brackish-water amphipod Gammarus duebeni Liljeborg. The works is unusual as it operates with saline sewage and has a tidally-based pattern of salinity fluctuation (S=13 to 34). Various responses of this unique amphipod population (sewage amphipods) have been compared with G. duebeni from the adjacent Looe River estuary (estuarine amphipods) in an attempt to identify long-term responses to sewage. Sewage amphipods were significantly smaller than their estuarine equivalents; the sewage population was biased significantly to males, whereas the sex ratio of the estuarine population significantly favours females. Compared with the estuary, the consistently lower oxygen levels in the works were reflected in significant differences in metabolism. Sewage amphipods maintained high levels of activity under hypoxia ( e.g. swimming), and the higher survival and lower rates of lactic acid accumulation under anoxia than estuarine individuals. In addition, sewage amphipods recovered more rapidly from anoxia and had a lower critical oxygen tension (p c) than estuarine amphipods. Sewage amphipods are exposed to higher levels of heavy metals associated with the domestic sewage and zinc concentrations are particularly elevated in the works. Exposure to elevated zinc concentrations resulted in similar patterns of body zinc uptake for sewage and estuarine Gammarus at high (30) and low (10) salinity, with zinc regulation apparently occuring to an external threshold of 200 γmgZn·dm -3. No consistent interpopulational differences in the effect ofzinc on zinc uptake or on osmoregulation have been identified. However, sewage amphipods had higher survival at all zinc/salinity combinations compared with estuarine individuals. These indicate that sewage amphipods are adapted to the unusual combination of conditions prevailing in the treatment works and, if reproductive

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.

Characteristics of fatty acid composition of Gammarus lacustris inhabiting lakes with and without fish.

PubMed

Makhutova, O N; Sharapova, T A; Kalachova, G S; Shulepina, S P; Gladyshev, M I

2016-01-01

The effect of a biotic factor--the presence of predatory fish in water--on the composition and content of fatty acids in crustaceans was studied in the populations of the lake amphipod Gammarus lacustris from two lakes with fish and three lakes without fish. It was found that, at an overall increase in the quantity and quality of food resources (namely, increase in the content of eicosapentaenoic acid and docosahexaenoic acid (DHA) in the biomass), the relative rate of DHA accumulation in gammarids in the lakes without fish is higher than in the lake with fish.

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.

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.

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.

Sexual selection and population divergence I: The influence of socially flexible cuticular hydrocarbon expression in male field crickets (Teleogryllus oceanicus).

PubMed

Pascoal, Sonia; Mendrok, Magdalena; Mitchell, Christopher; Wilson, Alastair J; Hunt, John; Bailey, Nathan W

2016-01-01

Debates about how coevolution of sexual traits and preferences might promote evolutionary diversification have permeated speciation research for over a century. Recent work demonstrates that the expression of such traits can be sensitive to variation in the social environment. Here, we examined social flexibility in a sexually selected male trait-cuticular hydrocarbon (CHC) profiles-in the field cricket Teleogryllus oceanicus and tested whether population genetic divergence predicts the extent or direction of social flexibility in allopatric populations. We manipulated male crickets' social environments during rearing and then characterized CHC profiles. CHC signatures varied considerably across populations and also in response to the social environment, but our prediction that increased social flexibility would be selected in more recently founded populations exposed to fluctuating demographic environments was unsupported. Furthermore, models examining the influence of drift and selection failed to support a role of sexual selection in driving population divergence in CHC profiles. Variation in social environments might alter the dynamics of sexual selection, but our results align with theoretical predictions that the role social flexibility plays in modulating evolutionary divergence depends critically on whether responses to variation in the social environment are homogeneous across populations, or whether gene by social environment interactions occur. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

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. Copyright © 2015 Elsevier Inc. All rights reserved.

Influence of Natural Thermal Gradients on Whole Animal Rates of Protein Synthesis in Marine Gammarid Amphipods

PubMed Central

Rastrick, Samuel P. S.; Whiteley, Nia M.

2013-01-01

Although temperature is known to have an important effect on protein synthesis rates and growth in aquatic ectotherms held in the laboratory, little is known about the effects of thermal gradients on natural populations in the field. To address this issue we determined whole-animal fractional rates of protein synthesis (ks) in four dominant species of gammarid amphipods with different distributions along the coasts of Western Europe from arctic to temperate latitudes. Up to three populations of each species were collected in the summer and ks measured within 48 h. Summer ks values were relatively high in the temperate species, Gammarus locusta, from Portugal (48°N) and Wales (53°N) and were maintained across latitudes by the conservation of translational efficiency. In sharp contrast, summer ks remained remarkably low in the boreal/temperate species G. duebeni from Wales, Scotland (58°N) and Tromsø (70°N), probably as a temporary energy saving strategy to ensure survival in rapidly fluctuating environments of the high intertidal. Values for ks increased in acclimated G. duebeni from Scotland and Tromsø showing a lack of compensation with latitude. In the subarctic/boreal species, G. oceanicus, summer ks remained unchanged in Scotland and Tromsø but fell significantly in Svalbard (79°N) at 5°C, despite a slight increase in RNA content. At 79°N, mean ks was 4.5 times higher in the circumpolar species G. setosus than in G. oceanicus due to a doubling in RNA content. The relationship between whole-animal protein synthesis rates and natural thermal gradients is complex, varies between species and appears to be associated with local temperatures and their variability, as well as changes in other environmental factors. PMID:23544122

Adaptation of Gammarus pulex to agricultural insecticide contamination in streams.

PubMed

Shahid, Naeem; Becker, Jeremias Martin; Krauss, Martin; Brack, Werner; Liess, Matthias

2018-04-15

Exposure to pesticides affects non-target aquatic communities, with substantial consequences on ecosystem services. Adaptation of exposed populations may reduce the effects of pesticides. However, it is not known under which conditions adaptation occurs when only a low toxic pressure from pesticides is present. Here, we show that Gammarus pulex, a dominant macroinvertebrate species in many agricultural streams, acquires increased tolerance to pesticides when recolonization from non-contaminated refuge areas is low. Populations in the field that were exposed to pesticides at concentrations several orders of magnitude below considerable acute effects showed almost 3-fold higher tolerance to the neonicotinoid insecticide clothianidin (mean EC 50 218μgL -1 ) compared with non-exposed populations (mean EC 50 81μgL -1 ). This tolerance of exposed populations increased from 2- to 4-fold with increasing distance to the next refuge area (0 to 10km). We conclude that the development of tolerance for non-target species may occur at very low concentrations, much below those affecting sensitive test organisms and also lower than those predicted to be safe by governmental risk assessment frameworks. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of CO2-related acidification on aspects of the larval development of the European lobster, Homarus gammarus (L.)

NASA Astrophysics Data System (ADS)

Arnold, K. E.; Findlay, H. S.; Spicer, J. I.; Daniels, C. L.; Boothroyd, D.

2009-03-01

Oceanic uptake of anthropogenic CO2 results in a reduction in pH termed "Ocean Acidification" (OA). Comparatively little attention has been given to the effect of OA on the early life history stages of marine animals. Consequently, we investigated the effect of culture in CO2-acidified sea water (approx. 1200 ppm, i.e. average values predicted using IPCC 2007 A1F1 emissions scenarios for year 2100) on early larval stages of an economically important crustacean, the European lobster Homarus gammarus. Culture in CO2-acidified sea water did not significantly affect carapace length or development of H. gammarus. However, there was a reduction in carapace mass during the final stage of larval development in CO2-acidified sea water. This co-occurred with a reduction in exoskeletal mineral (calcium and magnesium) content of the carapace. As the control and high CO2 treatments were not undersaturated with respect to any of the calcium carbonate polymorphs measured, the physiological alterations we record are most likely the result of acidosis or hypercapnia interfering with normal homeostatic function, and not a direct impact on the carbonate supply-side of calcification per se. Thus despite there being no observed effect on survival, carapace length, or zoeal progression, OA related (indirect) disruption of calcification and carapace mass might still adversely affect the competitive fitness and recruitment success of larval lobsters with serious consequences for population dynamics and marine ecosystem function.

Effect of CO2-related acidification on aspects of the larval development of the European lobster, Homarus gammarus (L.)

NASA Astrophysics Data System (ADS)

Arnold, K. E.; Findlay, H. S.; Spicer, J. I.; Daniels, C. L.; Boothroyd, D.

2009-08-01

Oceanic uptake of anthropogenic CO2 results in a reduction in pH termed "Ocean Acidification" (OA). Comparatively little attention has been given to the effect of OA on the early life history stages of marine animals. Consequently, we investigated the effect of culture in CO2-acidified sea water (approx. 1200 ppm, i.e. average values predicted using IPCC 2007 A1F1 emissions scenarios for year 2100) on early larval stages of an economically important crustacean, the European lobster Homarus gammarus. Culture in CO2-acidified sea water did not significantly affect carapace length of H. gammarus. However, there was a reduction in carapace mass during the final stage of larval development in CO2-acidified sea water. This co-occurred with a reduction in exoskeletal mineral (calcium and magnesium) content of the carapace. As the control and high CO2 treatments were not undersaturated with respect to any of the calcium carbonate polymorphs measured, the physiological alterations we record are most likely the result of acidosis or hypercapnia interfering with normal homeostatic function, and not a direct impact on the carbonate supply-side of calcification per se. Thus despite there being no observed effect on survival, carapace length, or zoeal progression, OA related (indirect) disruption of calcification and carapace mass might still adversely affect the competitive fitness and recruitment success of larval lobsters with serious consequences for population dynamics and marine ecosystem function.

[Decline of Gammarus lacustris Sars (Crustacea: Amphipoda) population in the delta of the Selenga River].

PubMed

Matafonov, D V; Bazova, N V

2014-01-01

We determined the amphipod population characteristics from the water bodies of the delta of the Selenga River, where Gammarus lacustris Sars, 1863 was industrially harvested until the 1990s. In 2011, the population density of G. lacustris varied from 80 to 10 200 in Lapkhai Lake and from 80 to 2320 ind./m2 in Krivaya Channel. The low population density (< 40 ind./m2) in Gryaznoe Lake, together with the absence of the species in the waters of the former Zhilishchenskoe Lake, confirms the indications of population density decline in the associated waters of the delta. Population growth of G. lacustris was limited primarily by changes in the hydromorphology of the lakes and waterways due to floods of the early 1990s and the subsequent period of extremely low flow of the Selenga River.

First endemic freshwater Gammarus from Crete and its evolutionary history-an integrative taxonomy approach.

PubMed

Hupało, Kamil; Mamos, Tomasz; Wrzesińska, Weronika; Grabowski, Michał

2018-01-01

The Mediterranean islands are known as natural laboratories of evolution with a high level of endemic biodiversity. However, most biodiversity assessments have focused mainly on terrestrial and marine fauna, leaving the freshwater animals aside. Crete is one of the largest islands in the Mediterranean Basin, with a long history of isolation from the continental mainland. Gammarid amphipods are often dominant in macrozoobenthic communities in European inland waters. They are widely used in biomonitoring and exotoxicological studies. Herein, we describe Gammarus plaitisi sp. nov., endemic to Cretan streams, based on morphological characters and a set of molecular species delimitation methods using mitochondrial cytochrome oxidase subunit I and 16S rRNA genes as well as nuclear 28S rDNA, ITS1 and EF1-alpha genes. The divergence of the new species is strongly connected with the geological history of the island supporting its continental origin.

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. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

Field deployment of a scope for growth assay involving Gammarus pulex, a freshwater benthic invertebrate.

PubMed

Maltby, L; Naylor, C; Calow, P

1990-06-01

Scope for growth (SfG) is a measure of the energy balance of an animal (i.e., the difference between energy intake and metabolic output). The SfG of marine invertebrates, particularly the mussel Mytilus edulis, has been successfully used as the basis of a field bioassay to detect a range of stresses both natural (temperature, food, salinity) and anthropogenic (hydrocarbons, sewage sludge). SfG of the freshwater amphipod Gammarus pulex was found to be a sensitive indicator of stress under laboratory conditions and here we describe the field deployment of this technique and present data from three field trials. In every case, SfG was reduced at the downstream polluted site compared with that at an upstream reference site. This reduction in SfG was the result of a decrease in energy intake (absorption) rather than an increase in energy expenditure (respiration).

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.

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.

Microplastics affect assimilation efficiency in the freshwater amphipod Gammarus fossarum.

PubMed

Blarer, Pascal; Burkhardt-Holm, Patricia

2016-12-01

An important issue in assessing microplastics is whether this newly emerging type of pollution affects freshwater invertebrates. This study was designed to examine the interactions between the amphipod Gammarus fossarum and two types of microplastics. To determine the ingestion and egestion of polyamide (PA) fibres (500 × 20 μm), amphipods were exposed to four concentrations (100, 540, 2680, 13,380 PA fibres cm -2 base area of glass beakers) and four exposure times (0.5, 2, 8, 32 h) as well as four post-exposure times (1, 2, 4, 16 h). We demonstrate a positive correlation between concentration and ingestion of PA fibres. Fibres were found in the gut after 0.5 h of exposure. Egestion was rapid and the digestive tract was empty 16 h after exposure ended. To investigate whether polystyrene (PS) beads (1.6 μm) can be taken up in the epithelial cells of the gut and the midgut glands, four concentrations (500, 2500, 12,500, 60,000 PS beads mL -1 ) were tested. Cryosections exhibited fluorescent PS beads only within the gut lumen. In a 28-day feeding experiment with both, fibres and beads, we studied the amphipod's feeding rate, assimilation efficiency and wet weight change. The exposure to PA fibres (2680 PA fibres cm -2 base area of glass beakers) significantly reduced the assimilation efficiency of the animals. While both tested polymer types are ingested and egested, PA fibres can impair the health and ecological functions of freshwater amphipods under continuous exposure.

Effects of endosulfan, thiamethoxam, and indoxacarb in combination with atrazine on multi-biomarkers in Gammarus kischineffensis.

PubMed

Demirci, Özlem; Güven, Kemal; Asma, Dilek; Öğüt, Serdal; Uğurlu, Pelin

2018-01-01

Studies addressing the toxicity of pesticides towards non-target organisms focus on the median lethal concentration and biochemical response of individual pesticides. However, when determining environmental risks, it is important to test the combined effects of pesticides, such as insecticides and herbicides, which are frequently used together in agricultural areas. Here we aimed to investigate the toxic effects of the combined use of the herbicide atrazine and the insecticides, endosulfan, indoxacarb, and thiamethoxam on Gammarus kischineffensis. To do this, we tested the activities of oxidative stress, detoxification, and neurotoxicity biomarkers. Compared to atrazine alone, we detected higher glutathione-S-transferase, catalase and superoxide dismutase activities (oxidative stress biomarkers) when atrazine was combined with either endosulfan or indoxacarb. However, higher IBR values were determined in organisms where pesticide mixtures were used according to individual use. Based on these results, mixtures of atrazine and other pesticides may cause synergistic effects and may be evidence of increased toxicity and oxidative stress. Copyright © 2017 Elsevier Inc. All rights reserved.

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.

Complex Genotype by Environment interactions and changing genetic architectures across thermal environments in the Australian field cricket, Teleogryllus oceanicus

PubMed Central

2011-01-01

Background Biologists studying adaptation under sexual selection have spent considerable effort assessing the relative importance of two groups of models, which hinge on the idea that females gain indirect benefits via mate discrimination. These are the good genes and genetic compatibility models. Quantitative genetic studies have advanced our understanding of these models by enabling assessment of whether the genetic architectures underlying focal phenotypes are congruent with either model. In this context, good genes models require underlying additive genetic variance, while compatibility models require non-additive variance. Currently, we know very little about how the expression of genotypes comprised of distinct parental haplotypes, or how levels and types of genetic variance underlying key phenotypes, change across environments. Such knowledge is important, however, because genotype-environment interactions can have major implications on the potential for evolutionary responses to selection. Results We used a full diallel breeding design to screen for complex genotype-environment interactions, and genetic architectures underlying key morphological traits, across two thermal environments (the lab standard 27°C, and the cooler 23°C) in the Australian field cricket, Teleogryllus oceanicus. In males, complex three-way interactions between sire and dam parental haplotypes and the rearing environment accounted for up to 23 per cent of the scaled phenotypic variance in the traits we measured (body mass, pronotum width and testes mass), and each trait harboured significant additive genetic variance in the standard temperature (27°C) only. In females, these three-way interactions were less important, with interactions between the paternal haplotype and rearing environment accounting for about ten per cent of the phenotypic variance (in body mass, pronotum width and ovary mass). Of the female traits measured, only ovary mass for crickets reared at the cooler

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.

Transgenerational deleterious effects of ocean acidification on the reproductive success of a keystone crustacean (Gammarus locusta).

PubMed

Borges, Francisco O; Figueiredo, Cátia; Sampaio, Eduardo; Rosa, Rui; Grilo, Tiago F

2018-07-01

Ocean acidification (OA) poses a global threat to marine biodiversity. Notwithstanding, marine organisms may maintain their performance under future OA conditions, either through acclimation or evolutionary adaptation. Surprisingly, the transgenerational effects of high CO 2 exposure in crustaceans are still poorly understood. For the first time, the present study investigated the transgenerational effect of OA, from hatching to maturity, of a key amphipod species (Gammarus locusta). Negative transgenerational effects were observed on survival of the acidified lineage, resulting in significant declines (10-15%) compared to the control groups in each generation. Mate-guarding duration was also significantly reduced under high CO 2 and this effect was not alleviated by transgenerational acclimation, indicating that precopulatory behaviours can be disturbed under a future high CO 2 scenario. Although OA may initially stimulate female investment, transgenerational exposure led to a general decline in egg number and fecundity. Overall, the present findings suggest a potential fitness reduction of natural populations of G. locusta in a future high CO 2 ocean, emphasizing the need of management tools towards species' sustainability. Copyright © 2018 Elsevier Ltd. All rights reserved.

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.

Microphallids in Gammarus insensibilis Stock, 1966 from a Black Sea lagoon: manipulation hypothesis going East?

PubMed

Kostadinova, A; Mavrodieva, R S

2005-09-01

Patterns of parasite site selection, variation in infection parameters and interspecific associations are examined in the light of new field data on larval microphallids in Gammarus insensibilis from a Black Sea lagoon. These patterns are discussed in relation to the predictions for the manipulative effect of Microphallus papillorobustus and its relationships with the other microphallid species based on studies on the French Mediterranean coast. Four species were recovered: Maritrema subdolum, Microphallus hoffmanni, M. papillorobustus and Levinseniella propinqua. The latter two were located in both corporal and cephalic segments, but the selection of brain appeared stronger for L. propinqua. M. subdolum was the first colonizer of amphipod population recruits, and unequivocally the dominant species in the lagoon. There was a significant positive relationship between the parasite load of all 4 species. Concurrent infections were exceedingly frequent, and no departures from random association were detected. We found no evidence that the cerebral metacercariae of M. papillorobustus consistently predict the parasite load of any of the other species in the system and identify sources for heterogeneity that may account for the differences between the Black Sea and the Mediterranean system: habitat heterogeneity, bird diversity and host-parasite systems used to infer relationships between microphallids.

Effects of increased temperatures on Gammarus fossarum under the influence of copper sulphate.

PubMed

Schmidlin, Lara; von Fumetti, Stefanie; Nagel, Peter

2015-03-01

The specialised fauna of freshwater springs will have to cope with a possible temperature rise owing to Global Change. It is affected additionally by contamination of the water with xenobiotics from human activities in the surrounding landscape. We assessed the combined effects of temperature increase and exposure to toxins in laboratory experiments by using copper sulphate as a model substance and Gammarus fossarum Koch, 1835, as the model organism. This amphipod is a common representative of the European spring fauna and copper ions are widespread contaminants, mainly from agricultural practice. The experiments were conducted in boxes placed in flow channels and the water temperatures were varied. The gammarids were fed with conditioned beech leaf discs. The feeding activity of the amphipods was quantified on the level of the organism; and the respiratory electron transport system (ETS) assay was conducted in order to determine changes on the cellular level in the test organisms. The results show that the feeding activity increased slightly with higher water temperature. The sub-lethal copper dose had no significant effect other than a trend towards lower feeding activity. The ETS activity was significantly higher at the higher water temperatures, and the copper ions significantly lowered the ETS activity of the organisms. The combination of the two methods was useful when testing for combined effects of environmental changes and pollutants on a species. From the results one can reasonably infer a higher risk of adverse effects with increase in water temperature and exposure to a particular heavy metal.

Bisphenol A in artificial indoor streams: II. Stress response and gonad histology in Gammarus fossarum (Amphipoda).

PubMed

Schirling, Martin; Jungmann, Dirk; Ladewig, Vanessa; Ludwichowski, Kai-Uwe; Nagel, Roland; Köhler, Heinz-R; Triebskorn, Rita

2006-03-01

The effects of the world wide-distributed chemical bisphenol A (BPA) on the endocrine system of vertebrates have been demonstrated in several studies. Here, we report on the impact of BPA (0, 5, 50 and 500 microg/l nominally, deduced effective concentrations 0, 0.24, 2.4, and 24.1 microg/l, respectively, all at 15 degrees C) on the 70 kD stress protein family (hsp70), the 90 kD stress protein family (hsp90), and gonad histology of the crustacean Gammarus fossarum exposed in artificial indoor streams. The animals were exposed for a maximum of 103 days and samples were taken at the beginning and at days 34, 69 and 103 of the experiment. Exposure to BPA resulted in accelerated maturation of oocytes in females and in a decline in the number and size of early vitellogenic oocytes. The level of hsp90, which plays a pivotal role in vertebrate sex steroid signal transduction, was significantly reduced by BPA. In all five streams, measured parameters did not indicate any captivity stress for a period of 69 days. Beyond this time, the mortality rate and proteotoxic effects, the latter measured by hsp70 expression, were found to be elevated.

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.

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.

Behavioural and physiological effects of the trophically transmitted cestode parasite, Cyathocephalus truncatus, on its intermediate host, Gammarus pulex.

PubMed

Franceschi, N; Rigaud, T; Moret, Y; Hervant, F; Bollache, L

2007-11-01

Some parasites with complex life-cycles are able to manipulate the behaviour of their intermediate hosts in a way that increases their transmission to the next host. Gammarids infected by the tapeworm Cyathocephalus truncatus (Cestoda: Spathebothriidea) are known to be more predated by fish than uninfected ones, but potential behavioural manipulation by the parasite has never been investigated. In this study, we tested the hypothesis that C. truncatus is able to manipulate the behaviour of one of its intermediate hosts, Gammarus pulex (Crustacea: Amphipoda). To assess if any behavioural change was linked to other phenotypic alterations, we also measured the immunity of infected and uninfected individuals and investigated the pathogenic effects of the parasite. Infected gammarids were significantly less photophobic than uninfected ones, but no effect of infection on the level of immune defence was found. The results on survival, swimming activity and oxygen consumption suggest that the parasite also has various pathogenic effects. However, the alteration in host phototaxis was not correlated to some of these pathogenic effects. Therefore, we propose that the modification in host reaction to light is a behavioural manipulation, explaining the previously observed increase of gammarid predation rate.

Carotenoids of two freshwater amphipod species (Gammarus pulex and G. roeseli) and their common acanthocephalan parasite Polymorphus minutus.

PubMed

Gaillard, Maria; Juillet, Cédrik; Cézilly, Frank; Perrot-Minnot, Marie-Jeanne

2004-09-01

Carotenoid compositions of two freshwater Gammarus species (Crustacea: Amphipoda) and of their common acanthocephalan parasite Polymorphus minutus were characterized. The effect of carotenoid uptake by the parasite was addressed by comparing the carotenoid content of uninfected and infected female hosts. Using high-pressure liquid chromatography (HPLC), co-chromatography of reference pigments and electron ionization mass spectrometry of collected HPLC fractions (EI-MS), several xanthophylls and non-polar compounds were identified. Seven kinds of carotenoids, mainly xanthophylls, were identified in gammarids. Astaxanthin was predominant, amounting to 40 wt.% of total carotenoid in both uninfected G. pulex and G. roeseli. By contrast, we found only non-polar compounds with a predominance of esterified forms of astaxanthin in P. minutus larvae. No significant effect of infection on carotenoid content was evidenced in G. pulex and G. roeseli females. Our study highlights the use of a Matrix Solid Phase Dispersion as an efficient extraction method of both xanthophylls and non-polar pigments in small samples, including lipid-rich ones as P. minutus parasite. We discuss on the presumptive pathway leading to the formation of free astaxanthin in gammarids via hydroxy compounds, and on the accumulation of esters of astaxanthin in parasites.

Antibiotic mixture effects on growth of the leaf-shredding stream detritivore Gammarus fossarum.

PubMed

Bundschuh, Mirco; Hahn, Torsten; Gessner, Mark O; Schulz, Ralf

2017-05-01

Pharmaceuticals contribute greatly to human and animal health. Given their specific biological targets, pharmaceuticals pose a significant environmental risk by affecting organisms and ecosystem processes, including leaf-litter decomposition. Although litter decomposition is a central process in forest streams, the consequences of exposure to pharmaceuticals remain poorly known. The present study assessed the impact of antibiotics as an important class of pharmaceuticals on the growth of the leaf-shredding amphipod Gammarus fossarum over 24 days. Exposure scenarios involved an antibiotic mixture (i.e. sulfamethoxazole, trimethoprim, erythromycin-H 2 O, roxithromycin, clarithromycin) at 0, 2 and 200 µg/L to assess impacts resulting from exposure to both water and food. The antibiotics had no effect on either leaf-associated fungal biomass or bacterial abundance. However, modification of leaf quality (e.g. through shifts in leaf-associated microbial communities) may have triggered faster growth of gammarids (assessed in terms of body mass gain) at the low antibiotic concentration relative to the control. At 200 µg/L, however, gammarid growth was not stimulated. This outcome might be due to a modified ability of the gut microflora to assimilate nutrients and carbon. Furthermore, the observed lack of increases in the diameter of the gammarids' peduncles, despite an increase in gammarid mass, suggests antibiotic-induced effects in the moulting cycle. Although the processes responsible for the observed effects have not yet been identified, these results suggest a potential role of food-quality, gammarid gut microflora and alteration in the moulting cycle in mediating impacts of antibiotics on these detritivores and the leaf decomposition process in streams.

Consequences of lower food intake on the digestive enzymes activities, the energy reserves and the reproductive outcome in Gammarus fossarum.

PubMed

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.

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. Copyright © 2014 Elsevier Inc. All rights reserved.

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

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.

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.

Associations Between Egg Capsule Morphology and Predation Among Populations of the Marine Gastropod, Nucella emarginata.

PubMed

Rawlings, T A

1990-12-01

Intraspecific variation in the morphology of egg capsules is ideal for assessing the costs and benefits of encapsulation, yet little is known about the extent of such variation among populations of a single species. In the present study, I compared capsule morphology among three populations of the intertidal gastropod, Nucella emarginata. Significant differences were found both in capsule wall thickness and capsule strength. Mean capsule wall thickness varied as much as 25% among populations, with the dry weight of capsular cases differing accordingly. Capsule strength, measured as resistance to puncturing and squeezing forces, also varied among populations, but did not directly reflect differences in capsule wall thickness. Despite extensive variation in capsule morphology within this species, the number and size of eggs contained within capsules of equal volume did not differ significantly among populations. I also compared the type of capsule-eating predators that were present at each site. Shore crabs, Hemigrapsus spp., were abundant at all three sites; however, the predatory isopods Idotea wosnesenskii were only present at sites containing relatively thick-walled capsules. Although Hemigrapsus and Idotea were able to chew through both thick- and thin-walled capsules, laboratory experiments revealed that Idotea preferentially opened thin-walled capsules. These results suggest that variation in capsule morphology among populations of N. emarginata may, at least in part, reflect selection for the protection of embryos against predation.

Pesticide body burden of the crustacean Gammarus pulex as a measure of toxic pressure in agricultural streams.

PubMed

Shahid, Naeem; Becker, Jeremias Martin; Krauss, Martin; Brack, Werner; Liess, Matthias

2018-06-22

Risk assessments of toxicants in aquatic environments are typically based on the evaluation of concentrations in water or sediment. However, concentrations in water are highly variable, while the body burden may provide a better time-integrated measure of pesticide exposure and potential effects in aquatic organisms. Here, we quantified pesticide body burdens in a dominant invertebrate species from agricultural streams, Gammarus pulex, compared them pesticide concentrations in water samples, and linked the pesticide contamination with observed ecological effects on macroinvertebrate communities. In total, 19 of 61 targeted analytes were found in the organisms, ranging from 0.037 to 93.94 ng g-1 (wet weight). Neonicotinoids caused the highest toxic pressure among the pesticides detected in G. pulex. Using linear solvation energy relationships (LSERs), we derived equivalent pesticide concentrations in stream water based on the body burden. These equivalent concentrations correlated with the concentrations in water samples collected after run-off (65% of variance explained). Pesticide pressure significantly affected the aquatic macroinvertebrate community structure, expressed as SPEARpesticides, and caused, on average, threefold increased insecticide tolerance in G. pulex as a result of adaptation. The toxic pressure derived from body burden and from water samples similarly explained the change in community structure (68% and 64%). However, the increased tolerance of G. pulex to pesticides was better explained by the toxicity derived from body burden (70%) than by the toxicity from water samples (53%). We conclude that the internal body burden of macroinvertebrates is suitable to assess the overall pesticide exposure and effects in agricultural streams.

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. Copyright © 2015 Elsevier B.V. All rights reserved.

Differential tolerance of two Gammarus pulex populations transplanted from different metallogenic regions to a polymetal gradient.

PubMed

Khan, Farhan R; Irving, Jennifer R; Bury, Nicolas R; Hogstrand, Christer

2011-03-01

The River Hayle, Cornwall, UK exhibits pronounced Cu and Zn concentration gradients which were used to compare the metal handling abilities of two populations of Gammarus pulex (Crustacea: Amphipoda). One population was native to the Hayle region (Drym) and presumably has been historically impacted by elevated Cu and Zn levels, whilst naïve gammarids were collected from the River Cray, Kent, UK. Both populations were subject to a 32 day in situ exposure at four R. Hayle sites (Drym, Godolphin, Relubbus and St. Erth). Mortality (LT50), Cu and Zn accumulation and sub-cellular distribution, and oxidative stress (malondialdehyde production) increased with the expected Cu and Zn bioavailabilities at the four sites (i.e. Godolphin>Relubbus>St. Erth>Drym). The naïve population experienced greater metal induced effects in terms of Cu and Zn accumulation, oxidative stress responses and lower LT50s. Analysis of Cu and Zn sub-cellular distribution, however, revealed no significant differences in metal handling. In both populations each metal was localised predominantly to the sub-cellular fraction containing metal bound to metallothionein-like proteins (MTLP) or that holding both metal-rich granules (MRG) and exoskeleton, MTLP and MRG binding being indicative of metal detoxification. However, a greater capacity for detoxified metal storage is not a mechanism implicated in the perceived tolerance of the historically impacted gammarids. Instead our results suggest that the historically impacted population was adapted for lower uptake of Cu and Zn leading to lower bioaccumulation, stress response and ultimately mortality. These results demonstrate not only the usefulness of the in situ methodology, but also that differences in population exposure history can cause significant differences in metal responses during exposure at higher concentrations. Copyright © 2011 Elsevier B.V. All rights reserved.

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

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.

Trophic relationships on a fucoid shore in south-western Iceland as revealed by stable isotope analyses, laboratory experiments, field observations and gut analyses

NASA Astrophysics Data System (ADS)

Steinarsdóttir, M. B.; Ingólfsson, A.; Ólafsson, E.

2009-04-01

Rocky shores in the North Atlantic are known for their zonation patterns of both algae and animals, which can be expected to greatly affect food availability to consumers at different height levels on the shore. We tested the hypothesis that consumers would feed on the most abundant suitable food source in their surroundings. In total 36 species/taxa of common primary producers and consumers were sampled for stable isotope analyses from a sheltered fucoid shore at Hvassahraun in south-western Iceland. A selection of these species was also collected seasonally and from different height levels. Feeding experiments, field observations and gut analyses were also conducted. Our results were in good overall agreement with pre-existing knowledge of trophic relationships in the rocky intertidal. Consumers often appeared to be assimilating carbon and nitrogen from the most common diet in their immediate surroundings. The predator Nucella lapillus was thus feeding on different prey at different height levels in accordance with different densities of prey species. When tested in the laboratory, individuals taken from low on the shore would ignore the gastropod Littorina obtusata, uncommon at that height level, even when starved, while individuals from mid-shore readily ate the gastropod. This indicated that some kind of learned behaviour was involved. There were, however, important exceptions, most noteworthy the relatively small contribution to herbivores, both slow moving (the gastropod L. obtusata) and fast moving (the isopod Idotea granulosa and the amphipod Gammarus obtusatus) of the dominant alga at this site, Ascophyllum nodosum. The recent colonizer Fucus serratus seemed to be favoured. Selective feeding was indicated both by isotope signatures as well as by results of feeding experiments. Seasonal migrations of both slow and fast moving species could partly explain patterns observed.

A rhythmic modulatory gating system in the stomatogastric nervous system of Homarus gammarus. III. Rhythmic control of the pyloric CPG.

PubMed

Cardi, P; Nagy, F

1994-06-01

1. Two modulatory neurons, P and commissural pyloric (CP), known to be involved in the long-term maintenance of pyloric central pattern generator operation in the rock lobster Homarus gammarus, are members of the commissural pyloric oscillator (CPO), a higher-order oscillator influencing the pyloric network. 2. The CP neuron was endogenously oscillating in approximately 30% of the preparations in which its cell body was impaled. Rhythmic inhibitory feedback from the pyloric pacemaker anterior burster (AB) neuron stabilized the CP neuron's endogenous rhythm. 3. The organization of the CPO is described. Follower commissural neurons, the F cells, and the CP neuron receive a common excitatory postsynaptic potential from another commissural neuron, the large exciter (LE). When in oscillatory state, CP in turn excites the LE neuron. This positive feedback may maintain long episodes of CP oscillations. 4. The pyloric pacemaker neurons follow the CPO rhythm with variable coordination modes (i.e., 1:1, 1:2) and switch among these modes when their membrane potential is modified. The CPO inputs strongly constrain the pyloric period, which as a result may adopt only a few discrete values. This effect is based on mechanisms of entrainment between the CPO and the pyloric oscillator. 5. Pyloric constrictor neurons show differential sensitivity from the pyloric pacemaker neurons with respect to the CPO inputs. Consequently, their bursting period can be a shorter harmonic of the bursting period of the pyloric pacemakers neurons. 6. The CPO neurons seem to be the first example of modulatory gating neurons that also give timing cues to a rhythmic pattern generating network.

45 CFR 670.20 - Designation of native birds.

Code of Federal Regulations, 2012 CFR

2012-10-01

... chrysolophus. Rockhopper—Eudyptes crestatus. Petrel Antarctic—Thalassoica antarctica. Black-bellied Storm...—Pterodroma mollis. South-Georgia Diving—Pelecanoides georgicus. White-bellied Storm—Fregetta grallaria. White-chinned—Procellaria aequinoctialis. White-headed—Pterodroma lessoni. Wilson's Storm—Oceanites oceanicus...

45 CFR 670.20 - Designation of native birds.

Code of Federal Regulations, 2014 CFR

2014-10-01

... chrysolophus. Rockhopper—Eudyptes crestatus. Petrel Antarctic—Thalassoica antarctica. Black-bellied Storm...—Pterodroma mollis. South-Georgia Diving—Pelecanoides georgicus. White-bellied Storm—Fregetta grallaria. White-chinned—Procellaria aequinoctialis. White-headed—Pterodroma lessoni. Wilson's Storm—Oceanites oceanicus...

45 CFR 670.20 - Designation of native birds.

Code of Federal Regulations, 2013 CFR

2013-10-01

... chrysolophus. Rockhopper—Eudyptes crestatus. Petrel Antarctic—Thalassoica antarctica. Black-bellied Storm...—Pterodroma mollis. South-Georgia Diving—Pelecanoides georgicus. White-bellied Storm—Fregetta grallaria. White-chinned—Procellaria aequinoctialis. White-headed—Pterodroma lessoni. Wilson's Storm—Oceanites oceanicus...

PET microplastics do not negatively affect the survival, development, metabolism and feeding activity of the freshwater invertebrate Gammarus pulex.

PubMed

Weber, Annkatrin; Scherer, Christian; Brennholt, Nicole; Reifferscheid, Georg; Wagner, Martin

2018-03-01

Over the past decade, microscopic plastic debris, known as microplastics, emerged as a contaminant of concern in marine and freshwater ecosystems. Although regularly detected in aquatic environments, the toxicity of those synthetic particles is not well understood. To address this, we investigated whether the exposure to microplastics adversely affects the amphipod Gammarus pulex, a key freshwater invertebrate. Juvenile (6-9 mm) and adult (12-17 mm) individuals were exposed to irregular, fluorescent polyethylene terephthalate fragments (PET, 10-150 μm; 0.8-4,000 particles mL -1 ) for 24 h. Results show that body burden after 24 h depends on the dose and age of G. pulex with juveniles ingesting more microplastics than adults. After chronic exposure over 48 d, microplastics did not significantly affect survival, development (molting), metabolism (glycogen, lipid storage) and feeding activity of G. pulex. This demonstrates that even high concentrations of PET particles did not negatively interfere with the analyzed endpoints. These results contradict previous research on marine crustaceans. Differences may result from variations in the exposure regimes (e.g., duration, particle concentrations), plastic characteristics (e.g., type, size, shape, additives) as well as the species-specific morphological, physiological and behavioral traits. As a detritivorous shredder G. pulex is adapted to feed on non-digestible materials and might, therefore, be less sensitive towards exposure to synthetic particles. Accordingly, we argue that the autecology needs to be taken into account and that research should focus on identifying traits that render species susceptible to microplastic exposure. Copyright © 2017 Elsevier Ltd. All rights reserved.

A model predicting waterborne cadmium bioaccumulation in Gammarus pulex: the effects of dissolved organic ligands, calcium, and temperature.

PubMed

Pellet, Bastien; Geffard, Olivier; Lacour, Céline; Kermoal, Thomas; Gourlay-francé, Catherine; Tusseau-vuillemin, Marie-hélène

2009-11-01

Metal bioavailability depends on the presence of organic ligands in the water and on the concentrations of competitive cations. The present study aims at testing whether the diffusive gradient in thin films technique (DGT) could be used to take into account Cd speciation and its consequences on bioavailability in a bioaccumulation model and whether the influences of the Ca concentration and temperature also should be considered. Four kinetic experiments were conducted on Gammarus pulex: a calibration of Cd turnover rates and of the DGT lability in mineral water, a study of the influence f ethylenediaminetetraacetic acid (EDTA) and humic acids (HA) on uptake rates, and two experiments testing the influence of the Ca concentrations and temperature on Cd uptake clearance rates (ku). In mineral water, where Cd was considered fully labile, the ku was 0.46 L g⁻¹ d⁻¹, and the depuration rate was 0.032 d⁻¹. The initial Cd influxes were lowered significantly by additions of 10 μg L⁻¹ of EDTA or 10 mg L⁻¹ of HA in the water but not at 5 mg L⁻¹HA, even if DGT measurements proved that Cd formed Cd-HA complexes in that treatment. Increasing Ca concentrations lowered ku values, and a competitive inhibition model between Ca and Cd fitted the data. A 30% enhancement of k, values was observed when the temperature was increased by 8°C, which appeared comparatively as a weak effect. Thus, taking into account the metal speciation and the influence of the Ca concentration should improve Cd bioaccumulation modeling in amphipods. In freshwater, where metal bioavailability is reduced by the presence of dissolved organic matter, forecasting Cd waterborne uptake using the labile concentrations should allow robust comparisons between laboratory and field studies.

Metal release from contaminated leaf litter and leachate toxicity for the freshwater crustacean Gammarus fossarum.

PubMed

Maunoury-Danger, Florence; Felten, Vincent; Bojic, Clément; Fraysse, Fabrice; Cosin Ponce, Mar; Dedourge-Geffard, Odile; Geffard, Alain; Guérold, François; Danger, Michael

2018-04-01

Industrialization has left large surfaces of contaminated soils, which may act as a source of pollution for contiguous ecosystems, either terrestrial or aquatic. When polluted sites are recolonized by plants, dispersion of leaf litter might represent a non-negligible source of contaminants, especially metals. To evaluate the risks associated to contaminated leaf litter dispersion in aquatic ecosystems, we first measured the dynamics of metal loss from leaf litter during a 48-h experimental leaching. We used aspen (Populus tremula L.), a common tree species on these polluted sites, and collected leaf litter on three polluted sites (settling pond of a former steel mill) and three control sites situated in the same geographic area. Then, toxicity tests were carried out on individuals of a key detritivore species widely used in ecotoxicology tests, Gammarus fossarum (Crustacea, Amphipoda), with uncontaminated and contaminated leaf litter leachates, using a battery of biomarkers selected for their sensitivity to metallic stress. Leaf litters collected on polluted sites exhibited not only significantly higher cadmium and zinc concentrations but also lower lignin contents. All leaf litters released high amounts of chemical elements during the leaching process, especially potassium and magnesium, and, in a lesser extent, phosphorus, calcium, and trace metals (copper, cadmium, and zinc but not lead). Toxicity tests revealed that the most important toxic effects measured on G. fossarum were due to leaf litter leachates by themselves, whatever the origin of litter (from polluted or control sites), confirming the toxicity of such substances, probably due to their high content in phenolic compounds. Small additional toxic effects of leachates from contaminated leaf litters were only evidenced on gammarid lipid peroxidation, indicating that contaminated leaf litter leachates might be slightly more toxic than uncontaminated ones, but in a very reduced manner. Further studies will

UV-irradiation and leaching in water reduce the toxicity of imidacloprid-contaminated leaves to the aquatic leaf-shredding amphipod Gammarus fossarum.

PubMed

Englert, Dominic; Zubrod, Jochen P; Neubauer, Christoph; Schulz, Ralf; Bundschuh, Mirco

2018-05-01

Systemic neonicotinoid insecticides such as imidacloprid are increasingly applied against insect pest infestations on forest trees. However, leaves falling from treated trees may reach nearby surface waters and potentially represent a neonicotinoid exposure source for aquatic invertebrates. Given imidacloprid's susceptibility towards photolysis and high water solubility, it was hypothesized that the leaves' toxicity might be modulated by UV-irradiation during decay on the forest floor, or by leaching and re-mobilization of the insecticide from leaves within the aquatic ecosystem. To test these hypotheses, the amphipod shredder Gammarus fossarum was fed (over 7 d; n = 30) with imidacloprid-contaminated black alder (Alnus glutinosa) leaves that had either been pre-treated (i.e., leached) in water for up to 7 d or UV-irradiated for 1 d (at intensities relevant during autumn in Central Europe) followed by a leaching duration of 1 d. Gammarids' feeding rate, serving as sublethal response variable, was reduced by up to 80% when consuming non-pretreated imidacloprid-contaminated leaves compared to imidacloprid-free leaves. Moreover, both leaching of imidacloprid from leaves (for 7 d) as well as UV-irradiation reduced the leaves' imidacloprid load (by 46 and 90%) thereby mitigating the effects on gammarids' feeding rate to levels comparable to the respective imidacloprid-free controls. Therefore, natural processes, such as UV-irradiation and re-mobilization of foliar insecticide residues in water, might be considered when evaluating the risks systemic insecticide applications in forests might pose for aquatic organisms in nearby streams. Copyright © 2018 Elsevier Ltd. All rights reserved.

Biodegradable and Petroleum-Based Microplastics Do Not Differ in Their Ingestion and Excretion but in Their Biological Effects in a Freshwater Invertebrate Gammarus fossarum

PubMed Central

Straub, Sandrine; Hirsch, Philipp E.; Burkhardt-Holm, Patricia

2017-01-01

Research on the uptake and effects of bioplastics by aquatic organisms is still in its infancy. Here, we aim to advance the field by comparing uptake and effects of microplastic particles (MPP) of a biodegradable bioMPP (polyhydroxybutyrate (PHB)) and petroleum-based MPP (polymethylmethacrylate (PMMA)) in the freshwater amphipod Gammarus fossarum. Ingestion of both MPP in different particle sizes (32–250 µm) occurred after 24 h, with highest ingestion of particles in the range 32–63 µm and almost complete egestion after 64 h. A four-week effect-experiment showed a significant decrease of the assimilation efficiency in amphipods exposed to the petroleum-based MPP from week two onwards. The petroleum-based PMMA affected assimilation efficiency significantly in contrast to the biodegradable PHB, but overall differences in direct comparison of MPP types were small. Both MPP types led to a significantly lower wet weight gain relative to the control treatments. After four weeks, differences between both MPP types and silica, used as a natural particle control, were detected. In summary, these results suggest that both MPP types provoke digestive constraints on the amphipods, which go beyond those of natural non-palatable particles. This highlights the need for more detailed research comparing environmental effects of biodegradable and petroleum-based MPP and testing those against naturally occurring particle loads. PMID:28703776

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.

A new method for early assessment of effects of exposing two non-target crustacean species, Asellus aquaticus and Gammarus fossarum, to pesticides, a laboratory study.

PubMed

Lukancic, Simon; Zibrat, Uros; Mezek, Tadej; Jerebic, Andreja; Simcic, Tatjana; Brancelj, Anton

2010-05-01

A reliable method is needed for assessing the condition of aquatic animals and their resistance to toxic pollutants. The physiological responses of two freshwater crustaceans, Asellus aquaticus and Gammarus fossarum, following in vitro exposure to two pesticides (atrazine and imidacloprid), were measured by a combination of electron transport system (ETS) activity and respiration (R). Short-term exposure concentrations were selected according to standard toxicity tests and ranged from 0.01 mg L(-1) to 10 mg L(-1). When pesticide concentration was greater than 1 mg l(- 1) (which is below the LC(50) [48 hours] determined for both species), A. aquaticus and G. fossarum responded to short-term exposure with elevated levels of R and/or lower levels of ETS activity. One hour exposure to concentrations of up to 10 mg L(-1) showed an effect in both test species. Laboratory tests confirmed that G. fossarum is more sensitive to short-term pesticide exposure than A. aquaticus. The combination of these two methods provides a useful and effective tool for assessing the general condition of aquatic animals. It also enables to determine toxic effects on freshwater biota of specific or combined pollutants. ETS/R ratio may be used as a quick predictor of effects on organisms exposed to pesticides and other stress factors such as changes in temperature, light, salinity, oxygen concentration and food.

Biochemical responses of Gammarus pulex to malachite green solutions decolorized by Coriolus versicolor as a biosorbent under batch adsorption conditions optimized with response surface methodology.

PubMed

Yildirim, Nuran Cikcikoglu; Tanyol, Mehtap; Yildirim, Numan; Serdar, Osman; Tatar, Sule

2018-07-30

The current study was aimed to investigate the detoxifying and antioxidant enzyme response of Gammarus pulex exposed to malachite green (MG) after decolorization by Coriolus versicolor. Response surface methodology (RSM) was utilized to optimize the decolorization conditions of MG synthetic solutions by C. versicolor. Glutathione (GSH), malondialdehyde (MDA) levels and glutathione peroxidase (GP X ), catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), cytochrome P450 1A1 (CYP1A1) activities in G. pulex exposed to undecolorized (A1) and decolorized (A2) MG synthetic solution during 24 and 96 h were tested by using ELISA method. SOD and GP X enzyme activity was increased after decolorization (p > 0.05). CAT enzyme activity was increased in A2 group during 24 h (p > 0.05) but decreased during 96 h (p < 0.05). GSH levels were increased in A2 group during 24 and 96 h (p < 0.05). GST, CYP1A1 enzyme activity and MDA levels were decreased after decolorization during 96 h (p < 0.05). In this study, GSH levels, CAT, GST and CYP1A1 activities in G. pulex approved the capability of C. versicolor in MG decolorization, optimized with RSM. Copyright © 2018 Elsevier Inc. All rights reserved.

Additive effect of calcium depletion and low resource quality on Gammarus fossarum (Crustacea, Amphipoda) life history traits.

PubMed

Rollin, Marc; Coulaud, Romain; Danger, Michael; Sohm, Bénédicte; Flayac, Justine; Bec, Alexandre; Chaumot, Arnaud; Geffard, Olivier; Felten, Vincent

2018-04-01

Gammarus fossarum is an often-abundant crustacean detritivore that contributes importantly to leaf litter breakdown in oligotrophic, mainly heterotrophic, headwater streams. This species requires large amounts of Ca to moult, thus allowing growth and reproduction. Because resource quality is tightly coupled to the organism's growth and physiological status, we hypothesised that low Ca concentration [Ca] and low food resource quality (low phosphorus [P] and/or reduced highly unsaturated fatty acid [HUFA] contents) would interactively impair molecular responses (gene expression) and reproduction of G. fossarum. To investigate the effects of food resources quality, we experimentally manipulated the P content of sycamore leaves and also used diatoms because they contain high amounts of HUFAs. Three resource quality treatments were tested: low quality (LQ, unmanipulated leaves: low P content), high quality 1 (HQ1; P-manipulated leaves: high P content), and high quality 2 (unmanipulated leaves supplemented with a pellet containing diatoms: high P and HUFA content). Naturally, demineralised stream water was supplemented with CaSO 4 to obtain three Ca concentrations (2, 3.5, and 10.5 mg Ca L -1 ). For 21 days, pairs of G. fossarum were individually exposed to one of the nine treatments (3 [Ca] × 3 resource qualities). At the individual level, strong and significant delays in moult stage were observed in gammarids exposed to lower [Ca] and to lower resource quality, with additive effects lengthening the duration of the reproductive cycle. Effects at the molecular level were investigated by measuring expression of 12 genes involved in energy production, translation, or Ca or P homeostasis. Expression of ATP synthase beta (higher in HQ2), calcified cuticle protein (higher in HQ1 and HQ2), and tropomyosin (higher in HQ2 compared to HQ1) was significantly affected by resource quality, and significant additive effects on Ca transporting ATPase expression were induced by

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

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

Conflict between co-occurring manipulative parasites? An experimental study of the joint influence of two acanthocephalan parasites on the behaviour of Gammarus pulex.

PubMed

Cezilly, F; Gregoire, A; Bertin, A

2000-06-01

When two parasite species are manipulators and have different definitive hosts, there is a potential for conflict between them. Selection may then exist for either avoiding hosts infected with conflicting parasites, or for hijacking, i.e. competitive processes to gain control of the intermediate host. The evidence for both phenomena depends largely on the study of the relative competitive abilities of parasites within their common intermediate host. We studied the effects of simultaneous infection by a fish acanthocephalan parasite, Pomphorhynchus laevis, and a bird acanthocephalan parasite, Polymorphus minutus, on the behaviour of their common intermediate host, the amphipod Gammarus pulex. We compared the reaction to light and vertical distribution of individuals infected with both parasites to those of individuals harbouring a single parasite species and uninfected ones under controlled conditions. Compared to uninfected gammarids that were photophobic and tended to remain at the bottom of the water column, P. laevis-infected gammarids were attracted to light, whereas P. minutus-infected individuals showed a modified vertical distribution and were swimming closer to the water surface. The effects of both P. laevis and P. minutus appeared to be dependent only on their presence, not on their intensity. Depending on the behavioural trait under study, however, the outcome of the antagonism between P. laevis and P. minutus differed. The vertical distribution of gammarids harbouring both parasites was half-way between those of P. laevis- and P. minutus-infected individuals, whereas P. laevis was able to induce altered reaction to light even in the presence of P. minutus. We discuss our results in relation to the occurrence of active avoidance or hijacking between conflicting manipulative parasites and provide some recommendations for future research.

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.

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. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Isolation drives increased diversification rates in freshwater amphipods.

PubMed

Adams, Nicole E; Inoue, Kentaro; Seidel, Richard A; Lang, Brian K; Berg, David J

2018-06-14

Vicariance and dispersal events affect current biodiversity patterns in desert springs. Whether major diversification events are due to environmental changes leading to radiation or due to isolation resulting in relict species is largely unknown. We seek to understand whether the Gammarus pecos species complex underwent major diversification events due to environmental changes in the area leading either to radiation into novel habitats, or formation of relicts due to isolation. Specifically, we tested the hypothesis that Gammarus in the northern Chihuahuan Desert of New Mexico and Texas, USA are descendants of an ancient marine lineage now containing multiple undescribed species. We sequenced a nuclear (28S) and two mitochondrial (16S, COI) genes from gammarid amphipods representing 16 desert springs in the northern Chihuahuan Desert. We estimated phylogenetic relationships, divergence time, and diversification rates of the Gammarus pecos complex. Our results revealed that the region contained two evolutionarily independent lineages: a younger Freshwater Lineage that shared a most-recent-common-ancestor with an older Saline Lineage ∼66.3 MYA (95.6 - 42.4 MYA). Each spring system generally formed a monophyletic clade based on the concatenated dataset. Freshwater Lineage diversification rates were 2.0 - 9.8 times higher than rates of the Saline Lineage. A series of post-Cretaceous colonizations by ancestral Gammarus taxa was likely followed by isolation. Paleo-geological, hydrological, and climatic events in the Neogene-to-Quaternary periods (23.03 MYA - present) in western North America promoted allopatric speciation of both lineages. We suggest that Saline Lineage populations represent two undescribed Gammarus species, while the Freshwater Lineage shows repetition of fine-scale genetic structure in all major clades suggesting incipient speciation. Such ongoing speciation suggests that this region will continue to be a biodiversity hotspot for amphipods and other

Different natural organic matter isolates cause similar stress response patterns in the freshwater amphipod, Gammarus pulex.

PubMed

Bedulina, Darya S; Timofeyev, Maxim A; Zimmer, Martin; Zwirnmann, Elke; Menzel, Ralph; Steinberg, Christian E W

2010-02-01

Dissolved humic substances (HSs) are exogenous stressors to aquatic plants and animals which activate a variety of transcriptional and biochemical reactions or block photosynthesis. While there are consistent indications which structures may lead to reduced photosynthetic activity, there is much less clear information available on which HS structures or building blocks act as stressors in animals. Consequently, this work was designed to comparatively study the impact of natural organic matter (NOMs) from different sources on major anti-stress mechanisms in one single animal. We utilized major antioxidant responses and relative expression levels of stress proteins (small HSPs and HSP70) and expected that different HSs provoke different response patterns. We tested the freshwater amphipod Gammarus pulex which was collected from several shallow creeks in Northern Germany. All specimens were maintained in aerated 5-L tanks with filtered water from their natural environment at 10 degrees C with prior acclimation. Animals were fed ad libitum with a commercial preparation once every second day. The exposure water was exchanged with the same frequency. NOMs were isolated from three different sources: two from small brown-water lakes in Northern Germany by reverse osmosis and the third one as an aqueous extract from a black layer of a Brazilian sandbar soil (State of Rio de Janeiro). The rationale was to apply NOMs of contrasting quality. Chemical fingerprint features of the NOMs were taken by high-performance size exclusion chromatography. As stress parameters in the animals, the activities of peroxidase and catalase were recorded quantitatively, and stress proteins, HSP70, as well as small alpha-crystalline HSPs were analyzed semiquantitatively. The three NOMs clearly differed in molecular masses, humic substance contents, the moieties of polysaccharides, and low-molecular-weight substances. With the exception of one short-term response, the peroxidase activity increased

Acoustic experience shapes female mate choice in field crickets

PubMed Central

Bailey, Nathan W; Zuk, Marlene

2008-01-01

Female choice can drive the evolution of extravagant male traits. In invertebrates, the influence of prior social experience on female choice has only recently been considered. To better understand the evolutionary implications of experience-mediated plasticity in female choice, we investigated the effect of acoustic experience during rearing on female responsiveness to male song in the field cricket Teleogryllus oceanicus. Acoustic experience has unique biological relevance in this species: a morphological mutation has rendered over 90 per cent of males on the Hawaiian island of Kauai silent in fewer than 20 generations, impeding females' abilities to locate potential mates. Females reared in silent conditions mimicking Kauai were less discriminating of male calling song and more responsive to playbacks, compared with females that experienced song during rearing. Our results to our knowledge, are the first demonstration of long-term effects of acoustic experience in an arthropod, and suggest that female T. oceanicus may be able to compensate for the reduced availability of long-range male sexual signals by increasing their responsiveness to the few remaining signallers. Understanding the adaptive significance of experience-mediated plasticity in female choice provides insight into processes that facilitate rapid evolutionary change and shape sexual selection pressure in natural populations. PMID:18700205

Sex differences in metabolic rates in field crickets and their dipteran parasitoids.

PubMed

Kolluru, G R; Chappell, M A; Zuk, M

2004-11-01

Sex differences in metabolic rate (MR) can result from dimorphism in the performance of energetically demanding activities. Male crickets (Teleogryllus oceanicus) engage in costly calling and aggressive activity not performed by females. Consistent with this difference, we found higher maximal MR, factorial scope, and fat content in males than females. T. oceanicus song is also costly because it attracts the parasitoid fly Ormia ochracea. Parasitized crickets had reduced maximal MR consistent with a metabolic cost to harboring larvae. This cost was greater for females, either because females invest more heavily into reproduction at the expense of metabolic capacity, or because males are under stronger selection to respond to infection. Little is known about O. ochracea outside of its auditory system and parasitic lifestyle. We observed greater resting MR in male flies, possibly reflecting a sex difference in the requirement for metabolic power output, because male flies perform potentially costly mating behavior not seen in females. We found a positive relationship between larval density within a cricket and pupal resting MR, suggesting that crickets in good condition are able to both harbor more larvae and produce larvae with higher resting MR. These results reveal a complex interplay between the metabolism of crickets and their fly parasitoids.

Occupational allergy to aquarium fish food: red midge larva, freshwater shrimp, and earthworm. A clinical and immunological study.

PubMed

Meseguer Arce, J; Villajos, I M Sánchez-Guerrero; Iraola, V; Carnés, J; Fernández Caldas, E

2013-01-01

Chironomids seem to be the main cause of occupational allergy to aquarium fish food. The aim of this study was to investigate the pattern of occupational sensitization to 3 different arthropod species used as components of aquarium fish food. The study sample comprised 8 workers from a fish food packing department. The control group comprised 40 atopic patients (20 of whom were allergic to mites). We performed prick tests with extracts of red midge larva (Chironomus thummi), freshwater shrimp (Gammarus species), earthworm (Tubifex species), and other arthropod species and a battery of common inhalant allergens. We measured peak expiratory flow rate (PEFR) and specific immunoglobulin (Ig) E and performed a methacholine challenge test, nasal challenge test, and immunoblotting. Cross-reactivity analyses were completed using immunoblotting and CAP inhibition. Prick test results were positive to red midge larvae in 7 patients (87.5%), Gammarus in 5 (62.5%), Tubifex in 3 (37.5%), and mites in 6 (75%). In the mite-allergic controls, 30% had positive prick test results to red midge larvae. PEFR decreased > or = 20% during the packing process in all patients, and in 1 patient it indicated a dual asthmatic response. Methacholine challenge test results were positive in all participants. Nasal challenge tests were performed in 4 patients, and the results were positive. Specific IgE to red midge larvae was detected in 62.5%, Gammarus in 50%, and Tubifex in 16%. Bands of approximately 14-15 kDa and 31 kDa were observed in Gammarus and red midge larvae extracts. Cross-reactivity assays demonstrated that Gammarus totally inhibited red midge larvae, while Tubifex did so partially. Dermatophagoides pteronyssinus showed very low inhibitory capacity. Aquarium fish food arthropods are potent allergens with an elevated prevalence of sensitization and variable degree of crossreactivity. This is the first report of occupational allergy to Tubifex. More data are necessary to identify and

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.

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.

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.

Tide-associated biological rhythms of some White Sea littoral invertebrates.

PubMed

Gusev, O A; Golubev, A I

2001-01-01

We report the results from two years of laboratory observations of the tide-associated rhythms of activity of White Sea intertidal invertebrates, Mya arenaria (Bivalvia) and Gammarus finmarchicus (Amphipoda). The tidal associated activity of these invertebrates could not be estimate as a clear circatidal clock. Gammarus activity could be phase shifted by a 0.5 h exposure to turbulent water twice a day for 2-3 days. Mya's rhythm could be changed by a single drainage of aquariums lasting about 15 min. This kind of timing system may be a relatively primitive evolution feature. c2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

Behavioural and biochemical responses to metals tested alone or in mixture (Cd-Cu-Ni-Pb-Zn) in Gammarus fossarum: From a multi-biomarker approach to modelling metal mixture toxicity.

PubMed

Lebrun, Jérémie D; Uher, Emmanuelle; Fechner, Lise C

2017-12-01

Metals are usually present as mixtures at low concentrations in aquatic ecosystems. However, the toxicity and sub-lethal effects of metal mixtures on organisms are still poorly addressed in environmental risk assessment. Here we investigated the biochemical and behavioural responses of Gammarus fossarum to Cu, Cd, Ni, Pb and Zn tested individually or in mixture (M2X) at concentrations twice the levels of environmental quality standards (EQSs) from the European Water Framework Directive. The same metal mixture was also tested with concentrations equivalent to EQSs (M1X), thus in a regulatory context, as EQSs are proposed to protect aquatic biota. For each exposure condition, mortality, locomotion, respiration and enzymatic activities involved in digestive metabolism and moult were monitored over a 120h exposure period. Multi-metric variations were summarized by the integrated biomarker response index (IBR). Mono-metallic exposures shed light on biological alterations occurring at environmental exposure levels in gammarids and depending on the considered metal and gender. As regards mixtures, biomarkers were altered for both M2X and M1X. However, no additive or synergistic effect of metals was observed comparing to mono-metallic exposures. Indeed, bioaccumulation data highlighted competitive interactions between metals in M2X, decreasing subsequently their internalisation and toxicity. IBR values indicated that the health of gammarids was more impacted by M1X than M2X, because of reduced competitions and enhanced uptakes of metals for the mixture at lower, EQS-like concentrations. Models using bioconcentration data obtained from mono-metallic exposures generated successful predictions of global toxicity both for M1X and M2X. We conclude that sub-lethal effects of mixtures identified by the multi-biomarker approach can lead to disturbances in population dynamics of gammarids. Although IBR-based models offer promising lines of enquiry to predict metal mixture toxicity

Vitellogenin-like proteins in the freshwater amphipod Gammarus fossarum (Koch, 1835): functional characterization throughout reproductive process, potential for use as an indicator of oocyte quality and endocrine disruption biomarker in males.

PubMed

Jubeaux, Guillaume; Simon, Romain; Salvador, Arnaud; Quéau, Hervé; Chaumot, Arnaud; Geffard, Olivier

2012-05-15

This work focused on the validation of biological specificity of the quantitative LC-MS/MS assay by checking the natural variability of Vg levels during the reproductive cycle in Gammarus fossarum (i.e., including oogenesis and embryogenesis). Laboratory tests were performed for 21 days under controlled conditions to assess Vg changes in male and female gammarids after exposure to chemical stress. Females were exposed to two crustacean hormones, 20-hydroxyecdysone (0.01, 1 and 100 μg L⁻¹) and methyl-farnesoate (0.01, 1 and 100 μg L⁻¹). No effect was recorded for 20-hydroxyecdysone, whereas in females exposed to methyl-farnesoate a deleterious impact on Vg production was observed. Males were exposed to crustacean hormones 20-hydroxyecdysone (0.01, 1 and 100 μg L⁻¹) and methyl-farnesoate (0.01, 1 and 100 μg L⁻¹), the insecticide methoxyfenozide (0.001, 0.1 and 10 μg L⁻¹), the fungicide propiconazole (0.001, 0.1, 10 and 1000 μg L⁻¹), and the pharmaceutical products benzophenone, carbamazepine, cyproterone, and R-propranolol (0.001, 0.1, 10 and 1000 μg L⁻¹). Induction of Vg synthesis was recorded in males exposed to cyproterone, methoxyfenozide, methyl-farnesoate, and propiconazole. Finally, we validated the function of the ILIPGVGK peptide used to track vitellogenin in G. fossarum across reproductive processes (vitellogenesis and embryogenesis), and results confirmed the energy reserve role of Vg during embryo development. We show that oocyte surface measurement is directly related to Vg levels in the oocyte, constituting a reliable indicator of egg quality in G. fossarum. Consequently, it could be used as a reliable tool for biomonitoring programs. We recorded induction of Vg in male G. fossarum; however, the possible use of this tool as a specific biomarker of exposure to endocrine disruption should be confirmed in further studies. Copyright © 2012 Elsevier B.V. All rights reserved.

[Diversity and faunal analysis of crustaceans in Potatso National Park, Shangri-La, China].

PubMed

Shu, Shu-Sen; Chen, Fei-Zhou; Yang, Jun-Xing; Yang, Xiao-Jun; Chen, Xiao-Yong

2013-06-01

Potatso National Park was the first national park in mainland China, preceded by the earlier Bitahai Nature Reserve. Located in the northwest of Yunnan and on the southeast of Qinghai-Tibet plateau, Potatso is a typical low latitude and high elevation wetland nature reserve, with large areas of coniferous forest around alpine lakes and both wetland and water area ecosystems. In August, 2011, we undertook a survey of crustaceans in the park, sampling lakes, ponds, streams, and rivers throughout Potatso. We found a total of 29 species (including varieties) belonging to 24 genera and 11 families. Notable discoveries include Parartemiopsis sp, Arctodiaptomus parvispinus and Simocephalus congener, which are the first examples of these species to be recorded in China. Likewise, Gammarus bitaensis is a unique crustacean found only in Potatso National Park and Thermocyclops dumonti and Gammarus paucispinus are both endemic species to northwestern Yunnan. The overall faunal characteristics of crustaceans in the park also revealed several things about Potatso: (1) Cosmopolitan and Palaearctic elements reach 48.27% and 37.93%, clearly showing the Palaearctic element as the dominant fauna; (2) most of the crustacean, such as Arctodiaptomus parvispinus and Gammarus, are typical alpine types, confirming that Potatso has feature typical of alpine and plateau fauna; and (3) the proportion of endemic and rare crustacean species in Potatso National Park is approximately 10%, suggesting that the Potatso National Park in particular and the northwest of Yunnan in general have a unique geological and evolutionary history.

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)...

Individual and joint toxicity of the herbicide S-metolachlor and a metabolite, deethylatrazine on aquatic crustaceans: Difference between ecological groups.

PubMed

Maazouzi, C; Coureau, C; Piscart, C; Saplairoles, M; Baran, N; Marmonier, P

2016-12-01

We studied the individual and joint acute toxicity of S-metolachlor (SMOC) and deethylatrazine (DEA - a metabolite of atrazine) on different non-target freshwater crustaceans. We used animals from different ecological groups: two amphipods from surface running water (Gammarus pulex and Gammarus cf. orinos), an isopod from surface stagnant water (Asellus aquaticus) and an amphipod living in groundwater (Niphargus rhenorhodanensis). Organisms were exposed to different levels of SMOC and DEA, alone or in binary mixture. Temperature effect on SMOC toxicity was assessed by exposing G. pulex and N. rhenorhodanensis to SMOC at 11 °C and 15 °C. Studying mortality as the biological endpoint, N. rhenorhodanensis was more resistant than surface water species towards SMOC and DEA. Among surface water species, G. pulex was the most sensitive while Gammarus cf. orinos and A. aquaticus showed similar responses to both compounds. Temperature increase did not change SMOC toxicity but modify the shape and steepness of the dose-response curve. We used a Model Deviation Ratio (MDR) approach to evaluate the predictability of Concentration Addition (CA) and Independent Action (IA) models to mixture toxicity. Results indicated either an additive or an antagonistic or a synergistic interaction depending on the concentrations combination and the test species. Our finding conclusively show the suitability of CA and IA in predicting mixture toxicities but results should be interpreted with caution according to ecological group of exposed species in risk assessment procedures. Copyright © 2016 Elsevier Ltd. All rights reserved.

Changes in the composition of ichthyoplankton assemblage and plastic debris in mangrove creeks relative to moon phases.

PubMed

Lima, A R A; Barletta, M; Costa, M F; Ramos, J A A; Dantas, D V; Melo, P A M C; Justino, A K S; Ferreira, G V B

2016-07-01

Lunar influence on the distribution of fish larvae, zooplankton and plastic debris in mangrove creeks of the Goiana Estuary, Brazil, was studied over a lunar cycle. Cetengraulis edentulus, Anchovia clupeoides and Rhinosardinia bahiensis were the most abundant fish larvae (56·6%), independent of the moon phase. The full moon had a positive influence on the abundance of Gobionellus oceanicus, Cynoscion acoupa and Atherinella brasiliensis, and the new moon on Ulaema lefroyi. The full and new moons also influenced the number of zoeae and megalopae of Ucides cordatus, protozoeae and larvae of caridean shrimps, and the number of hard and soft plastic debris, both <5 and >5 mm. Micro and macroplastics were present in samples from all 12 creeks studied, at densities similar to the third most abundant taxon, R. bahiensis. Cetengraulis edentulus and R. bahiensis showed a strong positive correlation with the last quarter moon, when there was less zooplankton available in the creeks and higher abundance of microplastic threads. Anchovia clupeoides, Diapterus rhombeus, U. lefroyi and hard microplastics were positively associated with different moon phases, when calanoid copepods, Caridean larvae and zoeae of U. cordatus were highly available in the creeks. Cynoscion acoupa, G. oceanicus and A. brasiliensis were strongly associated with the full moon, when protozoeae of caridean shrimps and megalopae of U. cordatus were also highly available, as were hard and soft macroplastics, paint chips (<5 mm) and soft microplastics. The results reinforce the role of mangrove creeks as nursery habitats. The moon phases influenced the distribution of fish larvae species, zooplankton and plastic debris by changing their compositions and abundances in the mangrove creeks of the Goiana Estuary when under the influence of different tidal current regimes. © 2015 The Fisheries Society of the British Isles.

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…

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

Toxicity of Aqueous Filmforming Foams to Marine Organisms: Literature Review and Biological Assessment

DTIC Science & Technology

1985-07-01

mg/l)* Scud (Gammarus fasciatus) 1100 mg/l (840-1300 mg/l)* Algae - FC-203 concentrations 򒮨 mg/I did not prevent the growth of Chlorella ...gairdneri) 1800 mg/l Static Test Marine Organisms 96-Hr. LC 5 0 Mummichog (Fundulus heteroclitus) 1820 mg/l Static Test Grass shrimp (Palaemonetes vulgaris

Stream macroinvertebrate drift response to pulsed exposure of the synthetic pyrethroid lambda-cyhalothrin.

PubMed

Lauridsen, Rasmus B; Friberg, Nikolai

2005-10-01

Outdoor experimental channels were used to study the behavioral changes of stream macroinvertebrates exposed to a pulse of the pyrethroid insecticide lambda-cyhalothrin. The primary end point was the number of macroinvertebrates drifting, but the mobility of macroinvertebrates caught in the drift also was assessed. A specified number of two insect species, Baetis rhodani and Leuctra fusca/digitata, and of the amphipod Gammarus pulex were introduced into small replicated subsections of the experimental channels. Macroinvertebrates were allowed to acclimatize for 26 h prior to a 60-min pulsed exposure to lambda-cyhalothrin. Measurement was initiated 2 h before pesticide application and continued for the following 24 h. Pulse concentrations of lambda-cyhalothrin of 0.001, 0.01, 0.1, and 1.0 microg L(-1) were applied, and each experiment was replicated 8 times. All three species responded to the pesticide pulse with catastrophic drift. The 0.001 microg L(-1) treatment caused a significant increase in the drift of Gammarus, whereas the drift response threshold was 0.01 microg L(-1) for the two insect species. Drift response onset followed the applied pulse concentration, with the highest concentrations resulting in more individuals of all species entering drift at an early stage. The majority of individuals caught in drift samples during low concentrations showed no change in mobility. At the two highest concentrations, however, both Baetis and Leuctra were in the process of being immobilized, with Leuctra the more sensitive of the two. In contrast, only a few of the Gammarus individuals caught showed changes in mobility after the high-concentration treatments. The present study shows that lambda-cyhalothrin is a potential hazard for macroinvertebrate populations in headwater streams. The clear species-specific responses indicate that sublethal doses have the potential to change the macroinvertebrate community structure. (c) 2005 Wiley Periodicals, Inc.

40 CFR 799.3300 - Unsubstituted phenylenediamines.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Acute flow-through studies on the freshwater invertebrate Gammarus shall be conducted with o-, m-, and p... aquatic invertebrates, the ratio of 24 hour/96 hour LC50s is greater than or equal to 2; for gammarids... section. Testing shall be conducted in accordance with § 797.1600 of this chapter. (B) An invertebrate...

An assessment of oceanic seabird abundance and distribution off the southern Brazilian coast using observations obtained during deep-water fishing operations.

PubMed

Branco, J O; Fracasso, H A A; Pérez, J A A; Rodrigues-Filho, J L

2014-08-01

The use of discarded fish over baited hooks used in longline fishery, and fish caught in gillnets, as a food source for gulls, albatrosses and petrels has been intensively studied in northern and southern oceans. This study describes the occurrence and abundance of seabirds observed from 20 foreign vessels which operated during the period between July 2001 and May 2005, off the southeastern and southern Brazilian coast. A total of 353,557 seabirds were observed; comprising eight families and 28 species. The most abundant species was Procellaria conspicillata followed by Daption capense, Puffinus gravis, Thalassarche melanophrys and Oceanites oceanicus. Ten species of seabirds (392 individual birds) were incidentally captured in gillnets; and 122 birds (9 species) by longline hooks, with P. gravis, D. capense and Procellaria aequinoctialis having the largest capture rates.

Fish, Benthic-Macroinvertebrate, and Stream-Habitat Data From Two Estuaries Near Galveston Bay, Texas, 2000-2001

DTIC Science & Technology

2002-01-01

0 0 0 1 0 2 0 0 0 2 5 Amphipoda Hyalellidae Hyalella azteca ( Saussure ) 0 0 16 0 0 0 0 0 0 0 16 Capitellida Capitellidae Mediomastus ambiseta (Hartman...0 0 0 0 0 0 0 0 14 0 14 Amphipoda Gammaridae Gammarus sp. 0 0 0 0 0 0 0 0 28 0 28 Amphipoda Hyalellidae Hyalella azteca ( Saussure ) 47 0 18 0 0 0 0 0

Olfactory projection neuron pathways in two species of marine Isopoda (Peracarida, Malacostraca, Crustacea).

PubMed

Stemme, Torben; Eickhoff, René; Bicker, Gerd

2014-08-01

The neuroanatomy of the olfactory pathway has been intensely studied in many representatives of Malacostraca. Nevertheless, the knowledge about bilateral olfactory integration pathways is mainly based on Decapoda. Here, we investigated the olfactory projection neuron pathway of two marine isopod species, Saduria entomon and Idotea emarginata, by lipophilic dye injections into the olfactory neuropil. We show that both arms of the olfactory globular tract form a chiasm in the center of the brain, as known from several other crustaceans. Furthermore, the olfactory projection neurons innervate both the medulla terminalis and the hemiellipsoid body of the ipsi- and the contralateral hemisphere. Both protocerebral neuropils are innervated to a comparable extent. This is reminiscent of the situation in the basal decapod taxon Dendrobranchiata. Thus, we propose that an innervation by the olfactory globular tract of both the medulla terminalis and the hemiellipsoid body is characteristic of the decapod ground pattern, but also of the ground pattern of Caridoida. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

Release from bats: genetic distance and sensoribehavioural regression in the Pacific field cricket, Teleogryllus oceanicus

NASA Astrophysics Data System (ADS)

Fullard, James H.; Ter Hofstede, Hannah M.; Ratcliffe, John M.; Pollack, Gerald S.; Brigidi, Gian S.; Tinghitella, Robin M.; Zuk, Marlene

2010-01-01

The auditory thresholds of the AN2 interneuron and the behavioural thresholds of the anti-bat flight-steering responses that this cell evokes are less sensitive in female Pacific field crickets that live where bats have never existed (Moorea) compared with individuals subjected to intense levels of bat predation (Australia). In contrast, the sensitivity of the auditory interneuron, ON1 which participates in the processing of both social signals and bat calls, and the thresholds for flight orientation to a model of the calling song of male crickets show few differences between the two populations. Genetic analyses confirm that the two populations are significantly distinct, and we conclude that the absence of bats has caused partial regression in the nervous control of a defensive behaviour in this insect. This study represents the first examination of natural evolutionary regression in the neural basis of a behaviour along a selection gradient within a single species.

Short-term phenotypic plasticity in long-chain cuticular hydrocarbons

PubMed Central

Thomas, Melissa L.; Simmons, Leigh W.

2011-01-01

Cuticular hydrocarbons provide arthropods with the chemical equivalent of the visually extravagant plumage of birds. Their long chain length, together with the number and variety of positions in which methyl branches and double bonds occur, provide cuticular hydrocarbons with an extraordinary level of information content. Here, we demonstrate phenotypic plasticity in an individual's cuticular hydrocarbon profile. Using solid-phase microextraction, a chemical technique that enables multiple sampling of the same individual, we monitor short-term changes in cuticular hydrocarbon profiles of individual crickets, Teleogryllus oceanicus, in response to a social challenge. We experimentally manipulate the dominance status of males and find that dominant males, on losing fights with other dominant males, change their hydrocarbon profile to more closely resemble that of a subordinate. This result demonstrates that cuticular hydrocarbons can be far more responsive to changes in social dominance than previously realized. PMID:21367785

Male crickets adjust ejaculate quality with both risk and intensity of sperm competition.

PubMed

Simmons, Leigh W; Denholm, Amy; Jackson, Chantelle; Levy, Esther; Madon, Ewa

2007-10-22

Sperm competition theory predicts that males should increase their expenditure on the ejaculate with increasing risk of sperm competition, but decrease their expenditure with increasing intensity. There is accumulating evidence for sperm competition theory, based on examinations of testes size and/or the numbers of sperm ejaculated. However, recent studies suggest that ejaculate quality can also be subject to selection by sperm competition. We used experimental manipulations of the risk and intensity of sperm competition in the cricket, Teleogryllus oceanicus. We found that males produced ejaculates with a greater percentage of live sperm when they had encountered a rival male prior to mating. However, when mating with a female that presented a high intensity of sperm competition, males did not respond to risk, but produced ejaculates with a reduced percentage of live sperm. Our data suggest that males exhibit a fine-tuned hierarchy of responses to these cues of sperm competition.

Lotic community responses in the Lees Ferry reach

NASA Astrophysics Data System (ADS)

McKinney, T.; Rogers, R. S.; Ayers, A. D.; Persons, W. R.

Responses of periphyton, aquatic macrophytes, benthic macroinvertebrates, and rainbow trout to the 1996 controlled flood were investigated in the Lees Ferry tailwater reach below Glen Canyon Dam on the Colorado River. Lotic biota differed spatially and temporally in abundance and distribution following recession of flood waters, and there was no evidence that the flood benefitted trout or lower trophic levels. The flood was associated with short-term changes in lower trophic levels, but benthic vegetation and macrofauna with low resistance were resilient. Adverse impacts of the flood on lower trophic levels were greater and more prolonged in depositional areas than on cobble bar habitat, but recovery occurred in both habitat types 4-8 months after the flood. The flood likely resulted in some downstream displacement of smaller fish but had no effects on catch rate or condition indices of trout. Percentage of young-of-the-year trout 8 months after the event indicates that the flood did not prevent successful spawning. The flood had little direct influence on diets of trout, but relative gut volume increased in the week after the event, remained high in summer, and composition changed seasonally. Amphipods (Gammarus lacustris), chironomids, and snails were predominant food items, and Gammarus generally were eaten more often and comprised greater relative volume in the diet than other macroinvertebrate taxa.

Socially cued seminal fluid gene expression mediates responses in ejaculate quality to sperm competition risk.

PubMed

Simmons, Leigh W; Lovegrove, Maxine

2017-08-30

There is considerable evidence that males will increase the number of sperm ejaculated in response to sperm competition risk. However, whether they have the capacity to adjust seminal fluid components of the ejaculate has received less attention. Male crickets ( Teleogryllus oceanicus ) have been shown to adjust the viability of sperm in their ejaculate in response to sperm competition risk. Here we show that socially mediated plasticity in sperm viability is probably due, at least in part, to male adjustments in the protein composition of the seminal fluid. Seven seminal fluid protein genes were found to have an increased expression in males exposed to rival calls. Increased expression of these genes was correlated with increased sperm viability in whole ejaculates, and gene knockdown confirmed that at least one of these proteins promotes sperm viability. Our results lend support for recent theoretical models that predict complex responses in male allocation to seminal fluid composition in response to sperm competition risk. © 2017 The Author(s).

A Dihydropyridine-sensitive Voltage-dependent Calcium Channel in the Sarcolemmal Membrane of Crustacean Muscle

PubMed Central

Erxleben, Christian; Rathmayer, Werner

1997-01-01

Single-channel currents through calcium channels in muscle of a marine crustacean, the isopod Idotea baltica, were investigated in cell-attached patches. Inward barium currents were strongly voltage-dependent, and the channels were closed at the cell's resting membrane potential. The open probability (Po) increased e-fold for an 8.2 mV (±2.4, n = 13) depolarization. Channel openings were mainly brief (<0.3 ms) and evenly distributed throughout 100-ms pulses. Averaged, quasimacroscopic currents showed fast activation and deactivation and did not inactivate during 100-ms test pulses. Similarly, channel activity persisted at steadily depolarized holding potentials. With 200 mM Ba2+ as charge carrier, the average slope conductance from the unitary currents between +30 and +80 mV, was 20 pS (±2.6, n = 12). The proportion of long openings, which were very infrequent under control conditions, was greatly increased by preincubation of the muscle fibers with the calcium channel agonist, the dihydropyridine Bay K8644 (10–100 μM). Properties of these currents resemble those through the L-type calcium channels of mammalian nerve, smooth muscle, and cardiac muscle cells. PMID:9089439

Chronic toxicity of nickel-spiked freshwater sediments: variation in toxicity among eight invertebrate taxa and eight sediments

USGS Publications Warehouse

Besser, John M.; Brumbaugh, William G.; Ingersoll, Christopher G.; Ivey, Chris D.; Kunz, James L.; Kemble, Nile E.; Schlekat, Christian E.; Garman, Emily R.

2013-01-01

This study evaluated the chronic toxicity of Ni-spiked freshwater sediments to benthic invertebrates. A 2-step spiking procedure (spiking and sediment dilution) and a 2-stage equilibration period (10 wk anaerobic and 1 wk aerobic) were used to spike 8 freshwater sediments with wide ranges of acid-volatile sulfide (AVS; 0.94–38 µmol/g) and total organic carbon (TOC; 0.42–10%). Chronic sediment toxicity tests were conducted with 8 invertebrates (Hyalella azteca, Gammarus pseudolimnaeus, Chironomus riparius, Chironomus dilutus, Hexagenia sp., Lumbriculus variegatus, Tubifex tubifex, and Lampsilis siliquoidea) in 2 spiked sediments. Nickel toxicity thresholds estimated from species-sensitivity distributions were 97 µg/g and 752 µg/g (total recoverable Ni; dry wt basis) for sediments with low and high concentrations of AVS and TOC, respectively. Sensitive species were tested with 6 additional sediments. The 20% effect concentrations (EC20s) for Hyalella and Gammarus, but not Hexagenia, were consistent with US Environmental Protection Agency benchmarks based on Ni in porewater and in simultaneously extracted metals (SEM) normalized to AVS and TOC. For Hexagenia, sediment EC20s increased at less than an equimolar basis with increased AVS, and toxicity occurred in several sediments with Ni concentrations in SEM less than AVS. The authors hypothesize that circulation of oxygenated water by Hexagenia led to oxidation of AVS in burrows, creating microenvironments with high Ni exposure. Despite these unexpected results, a strong relationship between Hexagenia EC20s and AVS could provide a basis for conservative site-specific sediment quality guidelines for Ni.

Chronic toxicity of nickel-spiked freshwater sediments: variation in toxicity among eight invertebrate taxa and eight sediments.

PubMed

Besser, John M; Brumbaugh, William G; Ingersoll, Christopher G; Ivey, Chris D; Kunz, James L; Kemble, Nile E; Schlekat, Christian E; Garman, Emily Rogevich

2013-11-01

This study evaluated the chronic toxicity of Ni-spiked freshwater sediments to benthic invertebrates. A 2-step spiking procedure (spiking and sediment dilution) and a 2-stage equilibration period (10 wk anaerobic and 1 wk aerobic) were used to spike 8 freshwater sediments with wide ranges of acid-volatile sulfide (AVS; 0.94-38 µmol/g) and total organic carbon (TOC; 0.42-10%). Chronic sediment toxicity tests were conducted with 8 invertebrates (Hyalella azteca, Gammarus pseudolimnaeus, Chironomus riparius, Chironomus dilutus, Hexagenia sp., Lumbriculus variegatus, Tubifex tubifex, and Lampsilis siliquoidea) in 2 spiked sediments. Nickel toxicity thresholds estimated from species-sensitivity distributions were 97 µg/g and 752 µg/g (total recoverable Ni; dry wt basis) for sediments with low and high concentrations of AVS and TOC, respectively. Sensitive species were tested with 6 additional sediments. The 20% effect concentrations (EC20s) for Hyalella and Gammarus, but not Hexagenia, were consistent with US Environmental Protection Agency benchmarks based on Ni in porewater and in simultaneously extracted metals (SEM) normalized to AVS and TOC. For Hexagenia, sediment EC20s increased at less than an equimolar basis with increased AVS, and toxicity occurred in several sediments with Ni concentrations in SEM less than AVS. The authors hypothesize that circulation of oxygenated water by Hexagenia led to oxidation of AVS in burrows, creating microenvironments with high Ni exposure. Despite these unexpected results, a strong relationship between Hexagenia EC20s and AVS could provide a basis for conservative site-specific sediment quality guidelines for Ni. © 2013 SETAC.

The evolution of polyandry: patterns of genotypic variation in female mating frequency, male fertilization success and a test of the sexy-sperm hypothesis.

PubMed

Simmons, L W

2003-07-01

The sexy-sperm hypothesis predicts that females obtain indirect benefits for their offspring via polyandy, in the form of increased fertilization success for their sons. I use a quantitative genetic approach to test the sexy-sperm hypothesis using the field cricket Teleogryllus oceanicus. Previous studies of this species have shown considerable phenotypic variation in fertilization success when two or more males compete. There were high broad-sense heritabilities for both paternity and polyandry. Patterns of genotypic variance were consistent with X-linked inheritance and/or maternal effects on these traits. The genetic architecture therefore precludes the evolution of polyandry via a sexy-sperm process. Thus the positive genetic correlation between paternity in sons and polyandry in daughters predicted by the sexy-sperm hypothesis was absent. There was significant heritable variation in the investment by females in ovaries and by males in the accessory gland. Surprisingly there was a very strong genetic correlation between these two traits. The significance of this genetic correlation for the coevolution of male seminal products and polyandry is discussed.

Female crickets assess relatedness during mate guarding and bias storage of sperm towards unrelated males.

PubMed

Tuni, C; Beveridge, M; Simmons, L W

2013-06-01

Recent evidence shows that females exert a post-copulatory fertilization bias in favour of unrelated males to avoid the genetic incompatibilities derived from inbreeding. One of the mechanisms suggested for fertilization biases in insects is female control over transport of sperm to the sperm-storage organs. We investigated post-copulatory inbreeding-avoidance mechanisms in females of the cricket Teleogryllus oceanicus. We assessed the relative contribution of related and unrelated males to the sperm stores of double-mated females. To demonstrate unequivocally that biased sperm storage results from female control rather than cryptic male choice, we manipulated the relatedness of mated males and of males performing post-copulatory mate guarding. Our results show that when guarded by a related male, females store less sperm from their actual mate, irrespective of the relatedness of the mating male. Our data support the notion that inhibition of sperm storage by female crickets can act as a form of cryptic female choice to avoid the severe negative effects of inbreeding. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

Male-induced costs of mating for females compensated by offspring viability benefits in an insect.

PubMed

Garcia-Gonzalez, F; Simmons, L W

2010-10-01

Sexual conflict facilitates the evolution of traits that increase the reproductive success of males at the expense of components of female fitness. Theory suggests that indirect benefits are unlikely to offset the direct costs to females from antagonistic male adaptations, but empirical studies examining the net fitness pay-offs of the interaction between the sexes are scarce. Here, we investigate whether matings with males that invest intrinsically more into accessory gland tissue undermine female lifetime reproductive success (LRS) in the cricket Teleogryllus oceanicus. We found that females incur a longevity cost of mating that is proportional to the partner's absolute investment into the production of accessory gland products. However, male accessory gland weight positively influences embryo survival, and harmful ejaculate-induced effects are cancelled out when these are put in the context of female LRS. The direct costs of mating with males that sire offspring with higher viability are thus compensated by direct and possibly indirect genetic benefits in this species. © 2010 The Authors. Journal Compilation © 2010 European Society For Evolutionary Biology.

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. © 2014 The Authors. Journal of Animal Ecology © 2014 British Ecological Society.

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.

[Proboscis worm, Echinorhynchus gadi (Zoega) from a relict cod of Lake Mogil'noye].

PubMed

Kulachkova, V G; Timofeeva, T A

1977-01-01

Data on the extensiveness and intensity of infection of Kildin island cod with Echinorhynchus gadi in various seasons are given. E. gadi was proved to have a one-year life cycle and Gammarus duebeni as an intermediate host in the lake. A change of the parasite generations occurs in late summer--autumn. A high extensiveness (100%) and intensity of Kildin cod infection with E. gadi depends on the feeding habits (monophagy) and narrow distribution range of the host. Infection intensity is directly correlated with the fish age. Selfregulation of the parasite quantity in the host's intenstine is an important factor affecting the existence of E. gadi population in Lake Mogilnoye.

Population-dependent effects of ocean acidification.

PubMed

Wood, Hannah L; Sundell, Kristina; Almroth, Bethanie Carney; Sköld, Helén Nilsson; Eriksson, Susanne P

2016-04-13

Elevated carbon dioxide levels and the resultant ocean acidification (OA) are changing the abiotic conditions of the oceans at a greater rate than ever before and placing pressure on marine species. Understanding the response of marine fauna to this change is critical for understanding the effects of OA. Population-level variation in OA tolerance is highly relevant and important in the determination of ecosystem resilience and persistence, but has received little focus to date. In this study, whether OA has the same biological consequences in high-salinity-acclimated population versus a low-salinity-acclimated population of the same species was investigated in the marine isopod Idotea balthica.The populations were found to have physiologically different responses to OA. While survival rate was similar between the two study populations at a future CO2 level of 1000 ppm, and both populations showed increased oxidative stress, the metabolic rate and osmoregulatory activity differed significantly between the two populations. The results of this study demonstrate that the physiological response to OA of populations from different salinities can vary. Population-level variation and the environment provenance of individuals used in OA experiments should be taken into account for the evaluation and prediction of climate change effects. © 2016 The Author(s).

Population-dependent effects of ocean acidification

PubMed Central

Wood, Hannah L.; Sundell, Kristina; Almroth, Bethanie Carney; Sköld, Helén Nilsson; Eriksson, Susanne P.

2016-01-01

Elevated carbon dioxide levels and the resultant ocean acidification (OA) are changing the abiotic conditions of the oceans at a greater rate than ever before and placing pressure on marine species. Understanding the response of marine fauna to this change is critical for understanding the effects of OA. Population-level variation in OA tolerance is highly relevant and important in the determination of ecosystem resilience and persistence, but has received little focus to date. In this study, whether OA has the same biological consequences in high-salinity-acclimated population versus a low-salinity-acclimated population of the same species was investigated in the marine isopod Idotea balthica. The populations were found to have physiologically different responses to OA. While survival rate was similar between the two study populations at a future CO2 level of 1000 ppm, and both populations showed increased oxidative stress, the metabolic rate and osmoregulatory activity differed significantly between the two populations. The results of this study demonstrate that the physiological response to OA of populations from different salinities can vary. Population-level variation and the environment provenance of individuals used in OA experiments should be taken into account for the evaluation and prediction of climate change effects. PMID:27053741

Muscle precursor cells in the developing limbs of two isopods (Crustacea, Peracarida): an immunohistochemical study using a novel monoclonal antibody against myosin heavy chain

PubMed Central

Kreissl, S.; Uber, A.

2008-01-01

In the hot debate on arthropod relationships, Crustaceans and the morphology of their appendages play a pivotal role. To gain new insights into how arthropod appendages evolved, developmental biologists recently have begun to examine the expression and function of Drosophila appendage genes in Crustaceans. However, cellular aspects of Crustacean limb development such as myogenesis are poorly understood in Crustaceans so that the interpretative context in which to analyse gene functions is still fragmentary. The goal of the present project was to analyse muscle development in Crustacean appendages, and to that end, monoclonal antibodies against arthropod muscle proteins were generated. One of these antibodies recognises certain isoforms of myosin heavy chain and strongly binds to muscle precursor cells in malacostracan Crustacea. We used this antibody to study myogenesis in two isopods, Porcellio scaber and Idotea balthica (Crustacea, Malacostraca, Peracarida), by immunohistochemistry. In these animals, muscles in the limbs originate from single muscle precursor cells, which subsequently grow to form multinucleated muscle precursors. The pattern of primordial muscles in the thoracic limbs was mapped, and results compared to muscle development in other Crustaceans and in insects. Electronic supplementary material The online version of this article (doi:10.1007/s00427-008-0216-1) contains supplementary material, which is available to authorized users. PMID:18443823

The evil within? Systemic fungicide application in trees enhances litter quality for an aquatic decomposer-detritivore system.

PubMed

Newton, Kymberly; Zubrod, Jochen P; Englert, Dominic; Lüderwald, Simon; Schell, Theresa; Baudy, Patrick; Konschak, Marco; Feckler, Alexander; Schulz, Ralf; Bundschuh, Mirco

2018-06-05

Waterborne exposure towards fungicides is known to trigger negative effects in aquatic leaf-associated microbial decomposers and leaf-shredding macroinvertebrates. We expected similar effects when these organisms use leaf material from terrestrial plants that were treated with systemic fungicides as a food source since the fungicides may remain within the leaves when entering aquatic systems. To test this hypothesis, we treated black alder (Alnus glutinosa) trees with a tap water control or a systemic fungicide mixture (azoxystrobin, cyprodinil, quinoxyfen, and tebuconazole) at two worst-case application rates. Leaves of these trees were used in an experiment targeting alterations in two functions provided by leaf-associated microorganisms, namely the decomposition and conditioning of leaf material. The latter was addressed via the food-choice response of the amphipod shredder Gammarus fossarum. During a second experiment, the potential impact of long-term consumption of leaves from trees treated with systemic fungicides on G. fossarum was assessed. Systemic fungicide treatment altered the resource quality of the leaf material resulting in trends of increased fungal spore production and an altered community composition of leaf-associated fungi. These changes in turn caused a significant preference of Gammarus for microbially conditioned leaves that had received the highest fungicide treatment over control leaves. This higher food quality ultimately resulted in a higher gammarid growth (up to 300% increase) during the long-term feeding assay. Although the underlying mechanisms still need to be addressed, the present study demonstrates a positive indirect response in aquatic organisms due to systemic pesticide application in a terrestrial system. As the effects from the introduction of plant material treated with systemic fungicides strongly differ from those mediated via other pathways (e.g., waterborne exposure), our study provides a novel perspective of fungicide

Native and Non-Native Plants Provide Similar Refuge to Invertebrate Prey, but Less than Artificial Plants

PubMed Central

Grutters, Bart M. C.; Pollux, Bart J. A.; Verberk, Wilco C. E. P.; Bakker, Elisabeth S.

2015-01-01

Non-native species introductions are widespread and can affect ecosystem functioning by altering the structure of food webs. Invading plants often modify habitat structure, which may affect the suitability of vegetation as refuge and could thus impact predator-prey dynamics. Yet little is known about how the replacement of native by non-native vegetation affects predator-prey dynamics. We hypothesize that plant refuge provisioning depends on (1) the plant’s native status, (2) plant structural complexity and morphology, (3) predator identity, and (4) prey identity, as well as that (5) structurally similar living and artificial plants provide similar refuge. We used aquatic communities as a model system and compared the refuge provided by plants to macroinvertebrates (Daphnia pulex, Gammarus pulex and damselfly larvae) in three short-term laboratory predation experiments. Plant refuge provisioning differed between plant species, but was generally similar for native (Myriophyllum spicatum, Ceratophyllum demersum, Potamogeton perfoliatus) and non-native plants (Vallisneria spiralis, Myriophyllum heterophyllum, Cabomba caroliniana). However, plant refuge provisioning to macroinvertebrate prey depended primarily on predator (mirror carp: Cyprinus carpio carpio and dragonfly larvae: Anax imperator) and prey identity, while the effects of plant structural complexity were only minor. Contrary to living plants, artificial plant analogues did improve prey survival, particularly with increasing structural complexity and shoot density. As such, plant rigidity, which was high for artificial plants and one of the living plant species evaluated in this study (Ceratophyllum demersum), may interact with structural complexity to play a key role in refuge provisioning to specific prey (Gammarus pulex). Our results demonstrate that replacement of native by structurally similar non-native vegetation is unlikely to greatly affect predator-prey dynamics. We propose that modification of

Synergistic impacts by an invasive amphipod and an invasive fish explain native gammarid extinction.

PubMed

Beggel, S; Brandner, J; Cerwenka, A F; Geist, J

2016-07-14

Worldwide freshwater ecosystems are increasingly affected by invasive alien species. In particular, Ponto-Caspian gobiid fishes and amphipods are suspected to have pronounced effects on aquatic food webs. However, there is a lack of systematic studies mechanistically testing the potential synergistic effects of invasive species on native fauna. In this study we investigated the interrelations between the invasive amphipod Dikerogammarus villosus and the invasive fish species Neogobius melanostomus in their effects on the native amphipod Gammarus pulex. We hypothesized selective predation by the fish as a driver for displacement of native species resulting in potential extinction of G. pulex. The survival of G. pulex in the presence of N. melanostomus in relation to the presence of D. villosus and availability of shelter was analyzed in the context of behavioural differences between the amphipod species. Gammarus pulex had a significantly higher susceptibility to predation by N. melanostomus compared to D. villosus in all experiments, suggesting preferential predation by this fish on native gammarids. Furthermore, the presence of D. villosus significantly increased the vulnerability of G. pulex to fish predation. Habitat structure was an important factor for swimming activity of amphipods and their mortality, resulting in a threefold decrease in amphipods consumed with shelter habitat structures provided. Behavioral differences in swimming activity were additionally responsible for higher predation rates on G. pulex. Intraguild predation could be neglected within short experimental durations. The results of this study provide evidence for synergistic effects of the two invasive Ponto-Caspian species on the native amphipod as an underlying process of species displacements during invasion processes. Prey behaviour and monotonous habitat structures additionally contribute to the decline of the native gammarid fauna in the upper Danube River and elsewhere.

Is there a role for antioxidant carotenoids in limiting self-harming immune response in invertebrates?

PubMed

Cornet, Stéphane; Biard, Clotilde; Moret, Yannick

2007-06-22

Innate immunity relies on effectors, which produce cytotoxic molecules that have not only the advantage of killing pathogens but also the disadvantage of harming host tissues and organs. Although the role of dietary antioxidants in invertebrate immunity is still unknown, it has been shown in vertebrates that carotenoids scavenge cytotoxic radicals generated during the immune response. Carotenoids may consequently decrease the self-harming cost of immunity. A positive relationship between the levels of innate immune defence and circulating carotenoid might therefore be expected. Consistent with this hypothesis, we show that the maintenance and use of the prophenoloxidase system strongly correlate with carotenoid concentration in haemolymph within and among natural populations of the crustacean Gammarus pulex.

Maternal effects, but no good or compatible genes for sperm competitiveness in Australian crickets.

PubMed

Dowling, Damian K; Nystrand, Magdalena; Simmons, Leigh W

2010-05-01

Explanations for the evolution of polyandry often center on the idea that females garner genetic benefits for their offspring by mating multiply. Furthermore, postcopulatory processes are thought to be fundamental to enabling polyandrous females to screen for genetic quality. Much attention has focused on the potential for polyandrous females to accrue such benefits via a sexy- or good-sperm mechanism, whereby additive variation exists among males in sperm competitiveness. Likewise, attention has focused on an alternative model, in which offspring quality (in this context, the sperm competitiveness of sons) hinges on an interaction between parental haplotypes (genetic compatibility). Sperm competitiveness that is contingent on parental compatibility will exhibit nonadditive genetic variation. We tested these models in the Australian cricket, Teleogryllus oceanicus, using a design that allowed us to partition additive, nonadditive genetic, and parental variance for sperm competitiveness. We found an absence of additive and nonadditive genetic variance in this species, challenging the direct relevance of either model to the evolution of sperm competitiveness in particular, and polyandry in general. Instead, we found maternal effects that were possibly sex-linked or cytoplasmically linked. We also found effects of focal male age on sperm competitiveness, with small increments in age conferring more competitive sperm.

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

Effects of microplastics on European flat oysters, Ostrea edulis and their associated benthic communities.

PubMed

Green, Dannielle Senga

2016-09-01

Plastic pollution is recognised as an emerging threat to aquatic ecosystems, with microplastics now the most abundant type of marine debris. Health effects caused by microplastics have been demonstrated at the species level, but impacts on ecological communities remain unknown. In this study, impacts of microplastics on the health and biological functioning of European flat oysters (Ostrea edulis) and on the structure of associated macrofaunal assemblages were assessed in an outdoor mesocosm experiment using intact sediment cores. Biodegradable and conventional microplastics were added at low (0.8 μg L(-1)) and high (80 μg L(-1)) doses in the water column repeatedly for 60 days. Effects on the oysters were minimal, but benthic assemblage structures differed and species richness and the total number of organisms were ∼1.2 and 1.5 times greater in control mesocosms than in those exposed to high doses of microplastics. Notably, abundances of juvenile Littorina sp. (periwinkles) and Idotea balthica (an isopod) were ∼2 and 8 times greater in controls than in mesocosms with the high dose of either type of microplastic. In addition, the biomass of Scrobicularia plana (peppery furrow shell clam) was ∼1.5 times greater in controls than in mesocosms with the high dose of microplastics. This work indicates that repeated exposure to high concentrations of microplastics could alter assemblages in an important marine habitat by reducing the abundance of benthic fauna. Copyright © 2016 Elsevier Ltd. All rights reserved.

Castaways can't be choosers - Homogenization of rafting assemblages on floating seaweeds

NASA Astrophysics Data System (ADS)

Gutow, Lars; Beermann, Jan; Buschbaum, Christian; Rivadeneira, Marcelo M.; Thiel, Martin

2015-01-01

After detachment from benthic habitats, the epibiont assemblages on floating seaweeds undergo substantial changes, but little is known regarding whether succession varies among different seaweed species. Given that floating algae may represent a limiting habitat in many regions, rafting organisms may be unselective and colonize any available seaweed patch at the sea surface. This process may homogenize rafting assemblages on different seaweed species, which our study examined by comparing the assemblages on benthic and floating individuals of the fucoid seaweeds Fucus vesiculosus and Sargassum muticum in the northern Wadden Sea (North Sea). Species richness was about twice as high on S. muticum as on F. vesiculosus, both on benthic and floating individuals. In both seaweed species benthic samples were more diverse than floating samples. However, the species composition differed significantly only between benthic thalli, but not between floating thalli of the two seaweed species. Separate analyses of sessile and mobile epibionts showed that the homogenization of rafting assemblages was mainly caused by mobile species. Among these, grazing isopods from the genus Idotea reached extraordinarily high densities on the floating samples from the northern Wadden Sea, suggesting that the availability of seaweed rafts was indeed limiting. Enhanced break-up of algal rafts associated with intense feeding by abundant herbivores might force rafters to recolonize benthic habitats. These colonization processes may enhance successful dispersal of rafting organisms and thereby contribute to population connectivity between sink populations in the Wadden Sea and source populations from up-current regions.

Complete mitochondrial genomes of three crickets (Orthoptera: Gryllidae) and comparative analyses within Ensifera mitogenomes.

PubMed

Yang, Jing; Ren, Qianli; Huang, Yuan

2016-03-17

The complete mitochondrial genomes (mitogenomes) of Velarifictorus hemelytrus, Loxoblemmus equestris and Teleogryllus emma are 16123 bp, 16314 bp and 15697 bp, in size, respectively. All three mitogenomes possess the same gene order of the inversion of the gene cluster trnE-trnS^(AGN)-trnN compared with the ancestral gene order of Orthoptera. The atypical initiation codon for the cox1 gene in three crickets is TTA. Pronounced A skew and T skew have been found in Grylloidea comparing with Gryllotalpoidea and Tettigonioidea. The T-stretch in the minority strand is interrupted by C to form (T)_n(C)₂(T)_n sequences in five species of Gryllinae (V. hemelytrus, L. equestris, T. emma, T. oceanicus, T. commodus). This T-stretch variant with its neighbouring A-stretch variant (A-stretch is interrupted by G), which were discovered in the A+T-rich regions of all taxa from infraorder Gryllidea, could form a conserved stem-loop structure (including 15 ~ 17 base pairs). This potential stem-loop structure is a favorable candidate that may participate in the replication origin of the minority strand of Gryllidea mitogenome. Phylogenetic analysis indicated that within the Gryllinae, genus Teleogryllus and Velarifictorus are closely related, sister to the genus Loxoblemmus. The relationships among the five superfamilies of Ensifera presented here were ((Grylloidea, Gryllotalpoidea) (Tettigonioidea, (Hagloidea, Rhaphidophoroidea))).

Toxicity of five forest insecticides to cutthroat trout and two species of aquatic invertebrates

USGS Publications Warehouse

Woodward, D.F.; Mauck, W.L.

1980-01-01

The Northern Rocky Mountain region has had scattered infestation of the western spruce budworm Christoneura occidentalis since the early 1900's (U.S. DEPARTMENT OF AGRICULTURE (USDA) 1976b). On the basis of aerial surveys in 1975, TUNNOCK et al. (1976), estimated that budworm defoliation occurred on 2,278,804 acres of six National Forests in Montana. Since the use of DDT was banned in 1972, there has been a need to develop alternative insecticides with the efficacy of DDT but without its environmental risk. These insecticides must be effective in controlling the budworm, but should not persist in the environment or be toxic to other organisms. The organophosphate and carbamate insecticides are relatively nonpersistent and generally present only a moderate hazard to fish when applied according to label recommendations. The USDA Forest Service has been investigating the effectiveness of these two classes of insecticides against the budworm, and the Columbia National Fisheries Research Laboratory of the U.S. Fish and Wildlife Service has been cooperating with the Forest Service conducted pilot control projects in eastern Montana in 1975 and 1976 to determine the efficacy and environmental impact of acephate, carbaryl, and trichlorfon in controlling the western budworm (USDA 1976 b). In 1975, a similar type project was carried out in Maine with aminocarb, fenitrothion, and trichlorfon (USDA 1976 a).Acephate, fenitrothion, and trichlorfon (organophosphate insecticides) and aminocarb and carbaryl (carbamate insecticides) were selected for toxicity tests against cutthroat trout (Salmo clarki), a stonefly (Pteronarcella badia), and a freshwater amphipod (Gammarus pseudolimnaeus) edemic in streams of the northern Rocky Mountains. Populations of cutthroat trout inhabit lakes and streams in the Rocky Mountains which include some of the most pristine habitat and fisheries in North America. Pteronarcella and Gammarus provide forage for cutthroat trout and feed on decaying

Uptake and depuration of pharmaceuticals in aquatic invertebrates.

PubMed

Meredith-Williams, Melanie; Carter, Laura J; Fussell, Richard; Raffaelli, David; Ashauer, Roman; Boxall, Alistair B A

2012-06-01

The uptake and depuration of a range of pharmaceuticals in the freshwater shrimp (Gammarus pulex) and the water boatman (Notonecta glauca) was studied. For one compound, studies were also done using the freshwater snail Planobarius corneus. In G. pulex, bioconcentration factors (BCFs) ranged from 4.6 to 185,900 and increased in the order moclobemide < 5-fluoruracil < carbamazepine < diazepam < carvedilol < fluoxetine. In N. glauca BCFs ranged from 0.1 to 1.6 and increased in the order 5-fluorouracil < carbamazepine < moclobemide < diazepam < fluoxetine < carvedilol. For P. corneus, the BCF for carvedilol was 57.3. The differences in degree of uptake across the three organisms may be due to differences in mode of respiration, behaviour and the pH of the test system. BCFs of the pharmaceuticals for each organism were correlated to the pH-corrected liposome-water partition coefficient of the pharmaceuticals. Copyright © 2011 Elsevier Ltd. All rights reserved.

Comparing the Relative Importance of Water-Borne Cues and Direct Grazing for the Induction of Defenses in the Brown Seaweed Fucus vesiculosus

PubMed Central

Flöthe, Carla R.; John, Uwe; Molis, Markus

2014-01-01

Some seaweed species have been shown to release water-borne cues after herbivore attack, for example, to attract natural enemies of the herbivore. These cues may also be sensed by neighboring seaweeds and used to adjust their defenses in anticipation of a possible herbivore attack. Several studies indicated information transfer between seaweed individuals in the past, including the brown seaweed Fucus vesiculosus. Previous work showed induction of defenses in F. vesiculosus in response to water-borne cues released by isopod-grazed conspecifics. In contrast, another study on induced responses after exposure to cues from isopod-grazed neighbors using the same seaweed species yielded contradictory results. This study reassessed the ability of F. vesiculosus individuals to sense water-borne cues released by isopod-grazed neighbors in a series of experiments that monitored F. vesiculosus palatability in response to direct grazing by Idotea baltica and water-borne cues from isopod-grazed neighbors relative to unmanipulated seaweed pieces. Two-choice feeding assays were conducted with both fresh and reconstituted seaweed pieces. Direct grazing by I. baltica induced a chemical defense in F. vesiculosus, confirming results of previous studies. In contrast, evidence for increased herbivore resistance in seaweed pieces that were located downstream of isopod-grazed F. vesiculosus could not be provided. The lack of defense induction in response to grazing of conspecific neighbors may be explained by the environmental conditions and the scattered distribution of F. vesiculosus individuals in the intertidal zone of Helgoland, which may render resource investment in the emission and/or response to water-borne cues at this site unprofitable. PMID:25279662

Seabird guano fertilizes Baltic Sea littoral food webs.

PubMed

Gagnon, Karine; Rothäusler, Eva; Syrjänen, Anneli; Yli-Renko, Maria; Jormalainen, Veijo

2013-01-01

Nutrient enrichment in coastal marine systems can have profound impacts on trophic networks. In the Baltic Sea, the population of Great Cormorant (Phalacrocorax carbo sinensis) has increased nearly exponentially since the mid-1990 s, and colonies of these seabirds can be important sources of nitrogen enrichment for nearby benthic communities due to guano runoff. In this study we used stable isotope analyses and diet mixing models to determine the extent of nitrogen enrichment from cormorant colonies, as well as to examine any possible changes in herbivore diet preferences due to enrichment. We found significantly higher levels of δ(15)N in samples from colony islands than control islands for producers (the dominant macroalga Fucus vesiculosus, filamentous algae, and periphyton) and herbivores, as well as a positive correlation between enrichment and nest density in colony sites. We also found that enrichment increased over the breeding season of the cormorants, with higher enrichment in late summer than early summer. While the amount of total nitrogen did not differ between colony and control sites, the amount of guano-based nitrogen in algae was >50% in most sites, indicating high nitrogen enrichment from colonies. Herbivores (the isopod Idotea balthica and the gastropod Theodoxus fluviatilis) preferred feeding upon the dominant macroalga Fucus vesiculosus rather than on filamentous algae or periphyton in both control and colony, and there was a significant increase in periphyton consumption near colony sites. Overall, guano from cormorant colonies seems to have effects on both producers and herbivores, as well as the potential to modify algae-herbivore interactions.

Seabird Guano Fertilizes Baltic Sea Littoral Food Webs

PubMed Central

Gagnon, Karine; Rothäusler, Eva; Syrjänen, Anneli; Yli-Renko, Maria; Jormalainen, Veijo

2013-01-01

Nutrient enrichment in coastal marine systems can have profound impacts on trophic networks. In the Baltic Sea, the population of Great Cormorant (Phalacrocorax carbo sinensis) has increased nearly exponentially since the mid-1990s, and colonies of these seabirds can be important sources of nitrogen enrichment for nearby benthic communities due to guano runoff. In this study we used stable isotope analyses and diet mixing models to determine the extent of nitrogen enrichment from cormorant colonies, as well as to examine any possible changes in herbivore diet preferences due to enrichment. We found significantly higher levels of δ15N in samples from colony islands than control islands for producers (the dominant macroalga Fucus vesiculosus, filamentous algae, and periphyton) and herbivores, as well as a positive correlation between enrichment and nest density in colony sites. We also found that enrichment increased over the breeding season of the cormorants, with higher enrichment in late summer than early summer. While the amount of total nitrogen did not differ between colony and control sites, the amount of guano-based nitrogen in algae was >50% in most sites, indicating high nitrogen enrichment from colonies. Herbivores (the isopod Idotea balthica and the gastropod Theodoxus fluviatilis) preferred feeding upon the dominant macroalga Fucus vesiculosus rather than on filamentous algae or periphyton in both control and colony, and there was a significant increase in periphyton consumption near colony sites. Overall, guano from cormorant colonies seems to have effects on both producers and herbivores, as well as the potential to modify algae-herbivore interactions. PMID:23593452

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.

Bioaccumulation of per- and polyfluorinated alkyl substances (PFAS) in selected species from the Barents Sea food web.

PubMed

Haukås, Marianne; Berger, Urs; Hop, Haakon; Gulliksen, Bjørn; Gabrielsen, Geir W

2007-07-01

The present study reports concentrations and biomagnification potential of per- and polyfluorinated alkyl substances (PFAS) in species from the Barents Sea food web. The examined species included sea ice amphipod (Gammarus wilkitzkii), polar cod (Boreogadus saida), black guillemot (Cepphus grylle) and glaucous gull (Larus hyperboreus). These were analyzed for PFAS, polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethanes (DDTs) and polybrominated diphenyl ethers (PBDEs). Perfluorooctane sulfonate (PFOS) was the predominant of the detected PFAS. Trophic levels and food web transfer of PFAS were determined using stable nitrogen isotopes (delta(15)N). No correlation was found between PFOS concentrations and trophic level within species. However, a non-linear relationship was established when the entire food web was analyzed. Biomagnification factors displayed values >1 for perfluorohexane sulfonate (PFHxS), perfluorononanoic acid (PFNA), PFOS and SigmaPFAS(7). Multivariate analyses showed that the degree of trophic transfer of PFAS is similar to that of PCB, DDT and PBDE, despite their accumulation through different pathways.

Comparison in waterborne Cu, Ni and Pb bioaccumulation kinetics between different gammarid species and populations: Natural variability and influence of metal exposure history.

PubMed

Urien, N; Farfarana, A; Uher, E; Fechner, L C; Chaumot, A; Geffard, O; Lebrun, J D

2017-12-01

Kinetic parameters (uptake from solution and elimination rate constants) of Cu, Ni and Pb bioaccumulation were determined from two Gammarus pulex and three Gammarus fossrum wild populations collected from reference sites throughout France in order to assess the inter-species and the natural inter-population variability of metal bioaccumulation kinetics in that sentinel organism. For that, each population was independently exposed for seven days to either 2.5μgL -1 Cu (39.3nM), 40μgL -1 Ni (681nM) or 10μgL -1 Pb (48.3nM) in laboratory controlled conditions, and then placed in unexposed microcosms for a 7-day depuration period. In the same way, the possible influence of metal exposure history on subsequent metal bioaccumulation kinetics was addressed by collecting wild gammarids from three populations inhabiting stations contaminated either by Cd, Pb or both Pb and Ni (named pre-exposed thereafter). In these pre-exposed organisms, assessment of any changes in metal bioaccumulation kinetics was achieved by comparison with the natural variability of kinetic parameters defined from reference populations. Results showed that in all studied populations (reference and pre-exposed) no significant Cu bioaccumulation was observed at the exposure concentration of 2.5μgL -1 . Concerning the reference populations, no significant differences in Ni and Pb bioaccumulation kinetics between the two species (G. pulex and G. fossarum) was observed allowing us to consider all the five reference populations to determine the inter-population natural variability, which was found to be relatively low (kinetic parameters determined for each population remained within a factor of 2 of the minimum and maximum values). Organisms from the population exhibiting a Pb exposure history presented reduced Ni uptake and elimination rate constants, whereas no influence on Ni kinetic parameters was observed in organisms from the population exhibiting an exposure history to both Ni and Pb. Furthermore

The effect of maternal and paternal immune challenge on offspring immunity and reproduction in a cricket.

PubMed

McNamara, K B; van Lieshout, E; Simmons, L W

2014-06-01

Trans-generational immune priming is the transmission of enhanced immunity to offspring following a parental immune challenge. Although within-generation increased investment into immunity demonstrates clear costs on reproductive investment in a number of taxa, the potential for immune priming to impact on offspring reproductive investment has not been thoroughly investigated. We explored the reproductive costs of immune priming in a field cricket, Teleogryllus oceanicus. To assess the relative importance of maternal and paternal immune status, mothers and fathers were immune-challenged with live bacteria or a control solution and assigned to one of four treatments in which one parent, neither or both parents were immune-challenged. Families of offspring were reared to adulthood under a food-restricted diet, and approximately 10 offspring in each family were assayed for two measures of immunocompetence. We additionally quantified offspring reproductive investment using sperm viability for males and ovary mass for females. We demonstrate that parental immune challenge has significant consequences for the immunocompetence and, in turn, reproductive investment of their male offspring. A complex interaction between maternal and paternal immune status increased the antibacterial immune response of male offspring. This increased immune response was associated with a reduction in son's sperm viability, implicating a trans-generational resource trade-off between investment into immunocompetence and reproduction. Our data also show that these costs are sexually dimorphic, as daughters did not demonstrate a similar increase in immunity, despite showing a reduction in ovary mass. © 2014 The Authors. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

Rapid convergent evolution in wild crickets.

PubMed

Pascoal, Sonia; Cezard, Timothee; Eik-Nes, Aasta; Gharbi, Karim; Majewska, Jagoda; Payne, Elizabeth; Ritchie, Michael G; Zuk, Marlene; Bailey, Nathan W

2014-06-16

The earliest stages of convergent evolution are difficult to observe in the wild, limiting our understanding of the incipient genomic architecture underlying convergent phenotypes. To address this, we capitalized on a novel trait, flatwing, that arose and proliferated at the start of the 21st century in a population of field crickets (Teleogryllus oceanicus) on the Hawaiian island of Kauai. Flatwing erases sound-producing structures on male forewings. Mutant males cannot sing to attract females, but they are protected from fatal attack by an acoustically orienting parasitoid fly (Ormia ochracea). Two years later, the silent morph appeared on the neighboring island of Oahu. We tested two hypotheses for the evolutionary origin of flatwings in Hawaii: (1) that the silent morph originated on Kauai and subsequently introgressed into Oahu and (2) that flatwing originated independently on each island. Morphometric analysis of male wings revealed that Kauai flatwings almost completely lack typical derived structures, whereas Oahu flatwings retain noticeably more wild-type wing venation. Using standard genetic crosses, we confirmed that the mutation segregates as a single-locus, sex-linked Mendelian trait on both islands. However, genome-wide scans using RAD-seq recovered almost completely distinct markers linked with flatwing on each island. The patterns of allelic association with flatwing on either island reveal different genomic architectures consistent with the timing of two mutational events on the X chromosome. Divergent wing morphologies linked to different loci thus cause identical behavioral outcomes--silence--illustrating the power of selection to rapidly shape convergent adaptations from distinct genomic starting points. Copyright © 2014 Elsevier Ltd. All rights reserved.

Replicated evolutionary divergence in the cuticular hydrocarbon profile of male crickets associated with the loss of song in the Hawaiian archipelago.

PubMed

Simmons, L W; Thomas, M L; Gray, B; Zuk, M

2014-10-01

Female choice based on male secondary sexual traits is well documented, although the extent to which this selection can drive an evolutionary divergence in male traits among populations is less clear. Male field crickets Teleogryllus oceanicus attract females using a calling song and once contacted switch to courtship song to persuade them to mate. These crickets also secrete onto their cuticle a cocktail of long-chained fatty acids or cuticular hydrocarbons (CHCs). Females choose among potential mates based on the structure of male acoustic signals and on the composition of male CHC profiles. Here, we utilize two naturally occurring mutations that have arisen independently on two Hawaiian islands and render the male silent to ask whether the evolutionary loss of acoustic signalling can drive an evolutionary divergence in the alternative signalling modality, male CHC profiles. QST -FST comparisons revealed strong patterns of CHC divergence among three populations of crickets on the islands of Hawaii, Oahu and Kauai. Contrasts between wild-type and flatwing males on the islands of Oahu and Kauai indicated that variation in male CHC profiles within populations is associated with the loss of acoustic signalling; flatwing males had a relatively low abundance of long-chained CHCs relative to the short-chained CHCs that females find attractive. Given their dual functions in desiccation resistance and sexual signalling, insect CHCs may be particularly important traits for reproductive isolation and ultimately speciation. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

Rapid evolution and gene expression: a rapidly evolving Mendelian trait that silences field crickets has widespread effects on mRNA and protein expression.

PubMed

Pascoal, S; Liu, X; Ly, T; Fang, Y; Rockliffe, N; Paterson, S; Shirran, S L; Botting, C H; Bailey, N W

2016-06-01

A major advance in modern evolutionary biology is the ability to start linking phenotypic evolution in the wild with genomic changes that underlie that evolution. We capitalized on a rapidly evolving Hawaiian population of crickets (Teleogryllus oceanicus) to test hypotheses about the genomic consequences of a recent Mendelian mutation of large effect which disrupts the development of sound-producing structures on male forewings. The resulting silent phenotype, flatwing, persists because of natural selection imposed by an acoustically orienting parasitoid, but it interferes with mate attraction. We examined gene expression differences in developing wing buds of wild-type and flatwing male crickets using RNA-seq and quantitative proteomics. Most differentially expressed (DE) transcripts were down-regulated in flatwing males (625 up vs. 1716 down), whereas up- and down-regulated proteins were equally represented (30 up and 34 down). Differences between morphs were clearly not restricted to a single pathway, and we recovered annotations associated with a broad array of functions that would not be predicted a priori. Using a candidate gene detection test based on homology, we identified 30% of putative Drosophila wing development genes in the cricket transcriptome, but only 10% were DE. In addition to wing-related annotations, endocrine pathways and several biological processes such as reproduction, immunity and locomotion were DE in the mutant crickets at both biological levels. Our results illuminate the breadth of genetic pathways that are potentially affected in the early stages of adaptation. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Infection with an acanthocephalan manipulates an amphipod's reaction to a fish predator's odours.

PubMed

Baldauf, Sebastian A; Thünken, Timo; Frommen, Joachim G; Bakker, Theo C M; Heupel, Oliver; Kullmann, Harald

2007-01-01

Many parasites with complex life cycles increase the chances of reaching a final host by adapting strategies to manipulate their intermediate host's appearance, condition or behaviour. The acanthocephalan parasite Pomphorhynchus laevis uses freshwater amphipods as intermediate hosts before reaching sexual maturity in predatory fish. We performed a series of choice experiments with infected and uninfected Gammarus pulex in order to distinguish between the effects of visual and olfactory predator cues on parasite-induced changes in host behaviour. When both visual and olfactory cues, as well as only olfactory cues were offered, infected and uninfected G. pulex showed significantly different preferences for the predator or the non-predator side. Uninfected individuals significantly avoided predator odours while infected individuals significantly preferred the side with predator odours. When only visual contact with a predator was allowed, infected and uninfected gammarids behaved similarly and had no significant preference. Thus, we believe we show for the first time that P. laevis increases its chance to reach a final host by olfactory-triggered manipulation of the anti-predator behaviour of its intermediate host.

Total Catch of a Red-Listed Marine Species Is an Order of Magnitude Higher than Official Data

PubMed Central

Kleiven, Alf Ring; Olsen, Esben Moland; Vølstad, Jon Helge

2012-01-01

Accurate information on total catch and effort is essential for successful fisheries management. Officially reported landings, however, may be underestimates of total catch in many fisheries. We investigated the fishery for the nationally red-listed European lobster (Homarus gammarus) in south-eastern Norway. Probability-based strip transect surveys were used to count buoys in the study area in combination with catch per unit effort data obtained independently from volunteer catch diaries, phone interviews, and questionnaires. We estimate that recreational catch accounts for 65% of total catch in the study area. Moreover, our results indicate that only a small proportion (24%) of lobsters landed commercially were sold through the legal market and documented. Total estimated lobster catch was nearly 14 times higher than reported officially. Our study highlights the need for adequate catch monitoring and data collection efforts in coastal areas, presents a clear warning to resource managers that illegal, unreported and unregulated (IUU) fisheries in coastal areas should not be ignored, and shows the potential impact of recreational fisheries. PMID:22363583

Tracking living decapod larvae: mass staining of eggs with neutral red prior to hatching.

PubMed

Øresland, V; Horobin, R W

2012-04-01

Mass staining of decapod females carrying eggs, with subsequent identification of hatched larvae in the environment, is a research tool with great potential for field ecologists wishing to track the movements of larvae. For this to be achieved, however, numerous requirements must be met. These include adequate dye solubility, short staining time, dye penetration through different tissues, dye retention within the organism, absence of toxic and behavioral effects, low visibility to predators of stained larvae, no loss of staining owing to preservatives and low cost. The dye, neutral red, appears to meet most of these requirements. This dye was used in aliquots of 0.7 g/770 ml seawater applied to the females of Norway lobster (Nephrops norvegicus) and European lobster (Homarus gammarus) for 10 min. This procedure stained lobster eggs and embryos so that hatched larvae could be distinguished easily by fluorescence microscopy from larvae that hatched from unstained eggs. Stained larvae that were preserved in 4% formaldehyde in seawater were still stained after 1 year. Larvae should not come in contact with ethanol, because it extracts the dye rapidly.

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.

Do insect repellents induce drift behaviour in aquatic non-target organisms?

PubMed

Fink, Patrick; Moelzner, Jana; Berghahn, Ruediger; von Elert, Eric

2017-01-01

Synthetic insect repellents are compounds applied to surfaces to discourage insects, mainly mosquitoes, from landing on those surfaces. As some of these repellents have repeatedly been detected in surface waters at significant concentrations, they may also exert repellent effects on aquatic non-target organisms. In running water systems, aquatic invertebrates actively enter downstream drift in order to avoid unfavourable environmental conditions. We thus tested the hypothesis that the widely used insect repellents DEET (N,N-Diethyl-m-toluamide), EBAAP (3-[N-butyl-N-acetyl]-aminopropionic acid ethyl ester) and Icaridin (1-piperidinecarboxylic acid 2-(2-hydroxyethyl)-1-methylpropyl ester) induce downstream drift behaviour in the aquatic invertebrates Gammarus pulex (Crustacea, Amphipoda) and Cloeon dipterum (Insecta, Ephemeroptera), using a laboratory-scale drift assay. We found no clear increase in the drift behaviour of both invertebrate species across a concentration gradient of eight orders of magnitude and even beyond maximum environmental concentrations for any of the three repellents. We found no evidence for a direct drift-inducing activity of insect repellents on aquatic non-target organisms. Copyright © 2016 Elsevier Ltd. All rights reserved.

Predicting life-history adaptations to pollutants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maltby, L.

1995-12-31

Animals may adapt to pollutant stress so that individuals from polluted environments are less susceptible than those from unpolluted environments. In addition to such direct adaptations, animals may respond to pollutant stress by life-history modifications; so-called indirect adaptations. This paper will demonstrate how, by combining life-history theory and toxicological data, it is possible to predict stress-induced alterations in reproductive output and offspring size. Pollutant-induced alterations in age-specific survival in favor of adults and reductions in juvenile growth, conditions are predicted to select for reduced investment in reproduction and the allocation of this investment into fewer, larger offspring. Field observations onmore » the freshwater crustaceans, Asellus aquaticus and Gammarus pulex, support these predictions. Females from metal-polluted sites had lower investment in reproduction and produced larger offspring than females of the same species from unpolluted sites. Moreover, interpopulation differences in reproductive biology persisted in laboratory cultures indicating that they had a genetic basis and were therefore due to adaptation rather than acclimation. The general applicability of this approach will be considered.« less

The relation between invertebrate drift and two primary controls, discharge and benthic densities, in a large regulated river

USGS Publications Warehouse

Kennedy, Theodore A.; Yackulic, Charles B.; Cross, Wyatt F.; Grams, Paul E.; Yard, Michael D.; Copp, Adam J.

2014-01-01

1. Invertebrate drift is a fundamental process in streams and rivers. Studies from laboratory experiments and small streams have identified numerous extrinsic (e.g. discharge, light intensity, water quality) and intrinsic factors (invertebrate life stage, benthic density, behaviour) that govern invertebrate drift concentrations (# m−3), but the factors that govern invertebrate drift in larger rivers remain poorly understood. For example, while large increases or decreases in discharge can lead to large increases in invertebrate drift, the role of smaller, incremental changes in discharge is poorly described. In addition, while we might expect invertebrate drift concentrations to be proportional to benthic densities (# m−2), the benthic–drift relation has not been rigorously evaluated. 2. Here, we develop a framework for modelling invertebrate drift that is derived from sediment transport studies. We use this framework to guide the analysis of high-resolution data sets of benthic density and drift concentration for four important invertebrate taxa from the Colorado River downstream of Glen Canyon Dam (mean daily discharge 325 m3 s−1) that were collected over 18 months and include multiple observations within days. Ramping of regulated flows on this river segment provides an experimental treatment that is repeated daily and allowed us to describe the functional relations between invertebrate drift and two primary controls, discharge and benthic densities. 3. Twofold daily variation in discharge resulted in a >10-fold increase in drift concentrations of benthic invertebrates associated with pools and detritus (i.e. Gammarus lacustris and Potamopyrgus antipodarum). In contrast, drift concentrations of sessile blackfly larvae (Simuliium arcticum), which are associated with high-velocity cobble microhabitats, decreased by over 80% as discharge doubled. Drift concentrations of Chironomidae increased proportional to discharge. 4. Drift of all four taxa was

Seasonal distribution and interactions between plankton and microplastics in a tropical estuary

NASA Astrophysics Data System (ADS)

Lima, A. R. A.; Barletta, M.; Costa, M. F.

2015-11-01

The seasonal migration of a salt wedge and rainfall were the major factors influencing the spatiotemporal distribution of ichthyoplankton and microplastics along the main channel of the Goiana Estuary, NE Brazil. The most abundant taxa were the clupeids Rhinosardinia bahiensis and Harengula clupeola, followed by the achirid Trinectes maculatus (78.7% of the catch). Estuarine and mangrove larvae (e.g. Anchovia clupeoides, Gobionellus oceanicus), as well as microplastics were ubiquitous. During drier months, the salt wedge reaches the upper estuary and marine larvae (e.g. Cynoscion acoupa) migrated upstream until the zones of coastal waters influence. However, the meeting of waterfronts in the middle estuary forms a barrier that retains the microplastics in the upper and lower estuary most part of the year. During the late dry season, a bloom of zooplankton was followed by a bloom of fish larvae (12.74 ind. 100 m-3) and fish eggs (14.65 ind. 100 m-3) at the lower estuary. During the late rainy season, the high freshwater inflow flushed microplastics, together with the biota, seaward. During this season, a microplastic maximum (14 items 100 m-3) was observed, followed by fish larvae maximum (14.23 ind. 100 m-3) in the lower estuary. In contrast to fish larvae, microplastics presented positive correlation with high rainfall rates, being more strictly associated to flushing out/into the estuary than to seasonal variation in environmental variables. Microplastics represented half of fish larvae density. Comparable densities in the water column increase the chances of interaction between microplastics and fish larvae, including the ingestion of smaller fragments, whose shape and colour are similar to zooplankton prey.

Opposing patterns of intraspecific and interspecific differentiation in sex chromosomes and autosomes.

PubMed

Moran, Peter A; Pascoal, Sonia; Cezard, Timothee; Risse, Judith E; Ritchie, Michael G; Bailey, Nathan W

2018-05-22

Linking intraspecific and interspecific divergence is an important challenge in speciation research. X chromosomes are expected to evolve faster than autosomes and disproportionately contribute to reproductive barriers, and comparing genetic variation on X and autosomal markers within and between species can elucidate evolutionary processes that shape genome variation. We performed RADseq on a 16 population transect of two closely related Australian cricket species, Teleogryllus commodus and T. oceanicus, covering allopatry and sympatry. This classic study system for sexual selection provides a rare exception to Haldane's rule, as hybrid females are sterile. We found no evidence of recent introgression, despite the fact that the species coexist in overlapping habitats in the wild and interbreed in the laboratory. Putative X-linked loci showed greater differentiation between species compared with autosomal loci. However, population differentiation within species was unexpectedly lower on X-linked markers than autosomal markers, and relative X-to-autosomal genetic diversity was inflated above neutral expectations. Populations of both species showed genomic signatures of recent population expansions, but these were not strong enough to account for the inflated X/A diversity. Instead, most of the excess polymorphism on the X could better be explained by sex-biased processes that increase the relative effective population size of the X, such as interspecific variation in the strength of sexual selection among males. Taken together, the opposing patterns of diversity and differentiation at X versus autosomal loci implicate a greater role for sex-linked genes in maintaining species boundaries in this system. © 2018 John Wiley & Sons Ltd.

Bioaccumulation of Toxoplasma and Cryptosporidium by the crustacean Gammarus fossarum: involvement in biomonitoring survey and trophic transfer

USDA-ARS?s Scientific Manuscript database

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...

Biodynamic study of americium-241 accumulation in the cytosol of the hepatopancreas of the lobster Homarus gammarus.

PubMed

Goudard, F; Paquet, F; Durand, J P; Milcent, M C; Germain, P; Pieri, J

1994-08-01

In the lobster, most of the radionuclides ingested with contaminated food are concentrated in the digestive gland. Americium-241 accumulation in the hepatopancreas of the lobster was studied during the digestive cycle. Fractionations of cytosols at different times after ingestion of radioactive preys were performed by gel permeation chromatography to determine the distribution of 241Am in the different macromolecular components. 241Am was associated with ferritin during the whole digestive cycle. This observation suggests a correlation between 241Am distribution pathways and iron metabolism. The distribution of 241Am present in the other cytosolic proteins followed two major steps of accumulation which may be correlated to the evolution of the two main cellular types playing an important role in the digestive cycle (B and R type cells).

Uptake, biotransformation and elimination of selected pharmaceuticals in a freshwater invertebrate measured using liquid chromatography tandem mass spectrometry.

PubMed

Miller, Thomas H; Bury, Nicolas R; Owen, Stewart F; Barron, Leon P

2017-09-01

Methods were developed to assess uptake and elimination kinetics in Gammarus pulex of nine pharmaceuticals (sulfamethazine, carbamazepine, diazepam, temazepam, trimethoprim, warfarin, metoprolol, nifedipine and propranolol) using targeted LC-MS/MS to determine bioconcentration factors (BCFs) using a 96 h toxicokinetic exposure and depuration period. The derived BCFs for these pharmaceuticals did not trigger any regulatory thresholds and ranged from 0 to 73 L kg -1 (sulfamethazine showed no bioconcentration). Metabolism of chemicals can affect accurate BCF determination through parameterisation of the kinetic models. The added selectivity of LC-MS/MS allowed us to develop confirmatory methods to monitor the biotransformation of propranolol, carbamazepine and diazepam in G. pulex. Varying concentrations of the biotransformed products; 4-hydroxypropranolol sulphate, carbamazepine-10,11-epoxide, nordiazepam, oxazepam and temazepam were measured following exposure of the precursor compounds. For diazepam, the biotransformation product nordiazepam was present at higher concentrations than the parent compound at 94 ng g -1 dw. Overall, the results indicate that pharmaceutical accumulation is low in these freshwater amphipods, which can potentially be explained by the rapid biotransformation and excretion. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Cuticles of European and American lobsters harbor diverse bacterial species and differ in disease susceptibility

PubMed Central

Whitten, Miranda M A; Davies, Charlotte E; Kim, Anita; Tlusty, Michael; Wootton, Emma C; Chistoserdov, Andrei; Rowley, Andrew F

2014-01-01

Diseases of lobster shells have a significant impact on fishing industries but the risk of disease transmission between different lobster species has yet to be properly investigated. This study compared bacterial biofilm communities from American (Homarus americanus) and European lobsters (H. gammarus), to assess both healthy cuticle and diseased cuticle during lesion formation. Culture-independent molecular techniques revealed diversity in the bacterial communities of cuticle biofilms both within and between the two lobster species, and identified three bacterial genera associated with shell lesions plus two putative beneficial bacterial species (detected exclusively in healthy cuticle or healing damaged cuticle). In an experimental aquarium shared between American and European lobsters, heterospecific transmission of potentially pathogenic bacteria appeared to be very limited; however, the claws of European lobsters were more likely to develop lesions when reared in the presence of American lobsters. Aquarium biofilms were also examined but revealed no candidate pathogens for environmental transmission. Aquimarina sp. ‘homaria’ (a potential pathogen associated with a severe epizootic form of shell disease) was detected at a much higher prevalence among American than European lobsters, but its presence correlated more with exacerbation of existing lesions rather than with lesion initiation. PMID:24817518

Ecological effects of spring and late summer applications of lambda-cyhalothrin on freshwater microcosms.

PubMed

Van Wijngaarden, R P A; Brock, T C M; van den Brink, P J; Gylstra, R; Maund, S J

2006-02-01

The aim of the study was to compare the effects of the pyrethroid insecticide lambda-cyhalothrin (treated at 10, 25, 50, 100, 250 ng active ingredient a.i./L) on a drainage ditch ecosystem in spring and late summer. Microcosms (water volume approximately 430 L) were established using enclosures in a 50-cm-deep experimental ditch system containing communities typical of macrophyte-dominated freshwater ecosystems. Effects on macroinvertebrates, zooplankton, phytoplankton, macrophytes, and community metabolism were assessed and evaluated using univariate and multivariate statistical techniques. The macroinvertebrate community responded most clearly to treatment and, as anticipated, insects and crustaceans were among the most sensitive organisms. Statistical analysis showed that the underlying community structure was significantly different between the spring and summer experiments. However, the most sensitive species (Chaoborus obscuripes and Gammarus pulex) were abundant in spring as well as in late summer. In spring and late summer, only slight and transient effects were observed at the community level in the 10-ng/L treatment. Overall, the study did not show substantial differences in the responses of sensitive taxa between spring and late summer treatments, and effects thresholds were similar irrespective of season of treatment.

Uptake and effects of americium-241 on a brackishwater amphipod

NASA Astrophysics Data System (ADS)

Hoppenheit, M.; Murray, C. N.; Woodhead, D. S.

1980-03-01

The present paper reports the results of experimental work undertaken using the brackish-water amphipod Gammarus duebeni duebeni and the transuranium nuclide americium-241. Data on the accumulation of this actinide showed that the larger fraction of the total body burden is associated with the exoskeleton. It was found that the body burden remained constant in the range pH 8.0 6.5 even though the water concentrations changed markedly. It would thus appear that the concept of a concentration factor should be re-examined and it is proposed that a factor should be defined in terms of environmental and chemical parameters which represent the bioavailable fraction of the actinide. The effect of americium on survival and moulting was studied at two activity concentrations; the dose rates and absorbed doses under the experimental conditions employed have been estimated. The differences in survival rates between the control and irradiated groups were statistically analyzed and the significant difference at the higher concentration is believed to be due to a synergism between physiological stress and radiotoxicity of americium rather than the chemical toxicity of the element.

Anxiety-like behaviour increases safety from fish predation in an amphipod crustacea

PubMed Central

Banchetry, Loan; Cézilly, Frank

2017-01-01

Anxiety is an emotional state generally expressed as sustained apprehension of the environment and elevated vigilance. It has been widely reported in vertebrates and, more recently, in a few invertebrate species. However, its fitness value remains elusive. We investigated anxiety-like behaviour and its consequences in an amphipod crustacean, using electric shock as aversive stimuli, and pharmacological assays. An anxiety-like state induced by electric shocks in Gammarus fossarum was expressed through increased sheltering behaviour in the absence of predation risk, thereby showing the pervasive nature of such behavioural response. Increasing the number of electric shocks both increased refuge use and delayed behavioural recovery. The behavioural effect of electric shock was mitigated by pre-treatment with LY354740, a metabotropic glutamate receptor group II/III agonist. Importantly, we found that this modulation of decision-making under an anxiety-like state resulted in an increased survival to predation in microcosm experiments. This study confirms the interest in taking an evolutionary view to the study of anxiety and calls for further investigation on the costs counterbalancing the survival benefit of an elevated anxiety level evidenced here. PMID:29308271

Anxiety-like behaviour increases safety from fish predation in an amphipod crustacea.

PubMed

Perrot-Minnot, Marie-Jeanne; Banchetry, Loan; Cézilly, Frank

2017-12-01

Anxiety is an emotional state generally expressed as sustained apprehension of the environment and elevated vigilance. It has been widely reported in vertebrates and, more recently, in a few invertebrate species. However, its fitness value remains elusive. We investigated anxiety-like behaviour and its consequences in an amphipod crustacean, using electric shock as aversive stimuli, and pharmacological assays. An anxiety-like state induced by electric shocks in Gammarus fossarum was expressed through increased sheltering behaviour in the absence of predation risk, thereby showing the pervasive nature of such behavioural response. Increasing the number of electric shocks both increased refuge use and delayed behavioural recovery. The behavioural effect of electric shock was mitigated by pre-treatment with LY354740, a metabotropic glutamate receptor group II/III agonist. Importantly, we found that this modulation of decision-making under an anxiety-like state resulted in an increased survival to predation in microcosm experiments. This study confirms the interest in taking an evolutionary view to the study of anxiety and calls for further investigation on the costs counterbalancing the survival benefit of an elevated anxiety level evidenced here.

TOXICITY OF FLUCYTHRINATE TO GAMMARUS LACUSTRIS (AMPHIPODA), PTERONARCYS DORSATA (PLECOPTERA) AND BRACHYCENTRUS AMERICANUS (TRICHOPTERA): IMPORTANCE OF EXPOSURE DURATION

EPA Science Inventory

The effect of the synthetic pyrethroid flucythrinate on three non-target invertebrates was evaluated using continual and short-time exposure methods. Both methods show toxic action at measured concentrations 0.100 micrograms/litre. The use of both approaches pointed toward the im...

First Record of Paratenic Hosts of the Swimbladder Nematode Anguillicola crassus in North America.

PubMed

Li, WenXiang; Arnott, Stephen A; Jones, Katherine M M; Braicovich, Paola E; de Buron, Isaure; Wang, GuiTang; Marcogliese, David J

2015-10-01

Anguillicola crassus is a non-native parasite of the American eel, Anguilla rostrata. Since being introduced into North America, the nematode has spread rapidly across the range of A. rostrata, but paratenic hosts, which may facilitate parasite dispersion, have yet to be identified in the region. We investigated infection of larval A. crassus in 261 fish specimens belonging to 23 species and 12 orders collected from estuarine habitats in South Carolina (salinities 0-9 ppt) and Nova Scotia (10-18 ppt). A total of 35 fish belonging to 5 species and 3 orders were infected with the third-stage larvae (L3) of A. crassus, providing the first record of paratenic hosts for the parasite in North America. In South Carolina, high prevalence and abundance of the worm were found in spot (Leiostomus xanthurus), silver perch (Bairdiella chrysoura), and highfin goby (Gobionellus oceanicus), and a high prevalence but lower abundance was found in mummichog (Fundulus heteroclitus). In Nova Scotia, 2 nematodes were found in a single specimen of tomcod (Microgadus tomcod). All of the infected species are associated with a benthic lifestyle, and some of them are known to move between estuaries along the coastline. Lower infection rates in Nova Scotia may be associated with lower water temperatures and/or higher salinity of the sampling site. Most of the L3 were found encapsulated in mesenteric tissue around the intestine and stomach. No L4 or pre-adult worms were found. Mean body length of the L3 was smaller than L3 stages found in American eels from Cape Breton. This suggests that development of A. crassus is arrested at the L3 in the 5 fish species reported here, supporting their status as paratenic hosts.

Water-Borne Cues of a Non-Indigenous Seaweed Mediate Grazer-Deterrent Responses in Native Seaweeds, but Not Vice Versa

PubMed Central

Yun, Hee Young; Engelen, Aschwin H.; Santos, Rui O.; Molis, Markus

2012-01-01

Plants optimise their resistance to herbivores by regulating deterrent responses on demand. Induction of anti-herbivory defences can occur directly in grazed plants or from emission of risk cues to the environment, which modifies interactions of adjacent plants with, for instance, their consumers. This study confirmed the induction of anti-herbivory responses by water-borne risk cues between adjoining con-specific seaweeds and firstly examined whether plant-plant signalling also exists among adjacent hetero-specific seaweeds. Furthermore, differential abilities and geographic variation in plant-plant signalling by a non-indigenous seaweed as well as native seaweeds were assessed. Twelve-day induction experiments using the non-indigenous seaweed Sargassum muticum were conducted in the laboratory in Portugal and Germany with one local con-familiar (Portugal: Cystoseira humilis, Germany: Halidrys siliquosa) and hetero-familiar native species (Portugal: Fucus spiralis, Germany: F. vesiculosus). All seaweeds were grazed by a local isopod species (Portugal: Stenosoma nadejda, Germany: Idotea baltica) and were positioned upstream of con- and hetero-specific seaweeds. Grazing-induced modification in seaweed traits were tested in three-day feeding assays between cue-exposed and cue-free ( = control) pieces of both fresh and reconstituted seaweeds. Both Fucus species reduced their palatability when positioned downstream of isopod-grazed con-specifics. Yet, the palatability of non-indigenous S. muticum remained constant in the presence of upstream grazed con-specifics and native hetero-specifics. In contrast, both con-familiar (but neither hetero-familiar) native species reduced palatability when located downstream of grazed S. muticum. Similar patterns of grazer-deterrent responses to water-borne cues were observed on both European shores, and were almost identical between assays using fresh and reconstituted seaweeds. Hence, seaweeds may use plant-plant signalling to

Different Trophic Tracers Give Different Answers for the Same Bugs - Comparing a Stable Isotope and Fatty Acid Based Analysis of Resource Utilization in a Marine Isopod

NASA Astrophysics Data System (ADS)

Galloway, A. W. E.; Eisenlord, M. E.; Brett, M. T.

2016-02-01

Stable isotope (SI) based mixing models are the most common approach used to infer resource pathways in consumers. However, SI based analyses are often underdetermined, and consumer SI fractionation is usually unknown. The use of fatty acid (FA) tracers in mixing models offers an alternative approach that can resolve the underdetermined constraint. A limitation to both methods is the considerable uncertainty about consumer `trophic modification' (TM) of dietary FA or SI, which occurs as consumers transform dietary resources into tissues. We tested the utility of SI and FA approaches for inferring the diets of the marine benthic isopod (Idotea wosnesenskii) fed various marine macroalgae in controlled feeding trials. Our analyses quantified how the accuracy and precision of Bayesian mixing models was influenced by choice of algorithm (SIAR vs MixSIR), fractionation (assumed or known), and whether the model was under or overdetermined (seven sources and two vs 26 tracers) for cases where isopods were fed an exclusive diet of one of the seven different macroalgae. Using the conventional approach (i.e., 2 SI with assumed TM) resulted in average model outputs, i.e., the contribution from the exclusive resource = 0.20 ± 0.23 (0.00-0.79), mean ± SD (95% credible interval), that only differed slightly from the prior assumption. Using the FA based approach with known TM greatly improved model performance, i.e., the contribution from the exclusive resource = 0.91 ± 0.10 (0.58-0.99). The choice of algorithm only made a difference when fractionation was known and the model was overdetermined (FA approach). In this case SIAR and MixSIR had outputs of 0.86 ± 0.11 (0.48-0.96) and 0.96 ± 0.05 (0.79-1.00), respectively. This analysis shows the choice of dietary tracers and the assumption of consumer trophic modification greatly influence the performance of mixing model dietary reconstructions, and ultimately our understanding of what resources actually support aquatic consumers.

Water-borne cues of a non-indigenous seaweed mediate grazer-deterrent responses in native seaweeds, but not vice versa.

PubMed

Yun, Hee Young; Engelen, Aschwin H; Santos, Rui O; Molis, Markus

2012-01-01

Plants optimise their resistance to herbivores by regulating deterrent responses on demand. Induction of anti-herbivory defences can occur directly in grazed plants or from emission of risk cues to the environment, which modifies interactions of adjacent plants with, for instance, their consumers. This study confirmed the induction of anti-herbivory responses by water-borne risk cues between adjoining con-specific seaweeds and firstly examined whether plant-plant signalling also exists among adjacent hetero-specific seaweeds. Furthermore, differential abilities and geographic variation in plant-plant signalling by a non-indigenous seaweed as well as native seaweeds were assessed. Twelve-day induction experiments using the non-indigenous seaweed Sargassum muticum were conducted in the laboratory in Portugal and Germany with one local con-familiar (Portugal: Cystoseira humilis, Germany: Halidrys siliquosa) and hetero-familiar native species (Portugal: Fucus spiralis, Germany: F. vesiculosus). All seaweeds were grazed by a local isopod species (Portugal: Stenosoma nadejda, Germany: Idotea baltica) and were positioned upstream of con- and hetero-specific seaweeds. Grazing-induced modification in seaweed traits were tested in three-day feeding assays between cue-exposed and cue-free ( = control) pieces of both fresh and reconstituted seaweeds. Both Fucus species reduced their palatability when positioned downstream of isopod-grazed con-specifics. Yet, the palatability of non-indigenous S. muticum remained constant in the presence of upstream grazed con-specifics and native hetero-specifics. In contrast, both con-familiar (but neither hetero-familiar) native species reduced palatability when located downstream of grazed S. muticum. Similar patterns of grazer-deterrent responses to water-borne cues were observed on both European shores, and were almost identical between assays using fresh and reconstituted seaweeds. Hence, seaweeds may use plant-plant signalling to

Feeding type and development drive the ingestion of microplastics by freshwater invertebrates.

PubMed

Scherer, Christian; Brennholt, Nicole; Reifferscheid, Georg; Wagner, Martin

2017-12-05

Microscopic plastic items (microplastics) are ubiquitously present in aquatic ecosystems. With decreasing size their availability and potential to accumulate throughout food webs increase. However, little is known on the uptake of microplastics by freshwater invertebrates. To address this, we exposed species with different feeding strategies to 1, 10 and 90 µm fluorescent polystyrene spheres (3-3 000 particles mL -1 ). Additionally, we investigated how developmental stages and a co-exposure to natural particles (e.g., food) modulate microplastic ingestion. All species ingested microplastics in a concentration-dependent manner with Daphnia magna consuming up to 6 180 particles h -1 , followed by Chironomus riparius (226 particles h -1 ), Physella acuta (118 particles h -1 ), Gammarus pulex (10 particles h -1 ) and Lumbriculus variegatus (8 particles h -1 ). D. magna did not ingest 90 µm microplastics whereas the other species preferred larger microplastics over 1 µm in size. In C. riparius and D. magna, size preference depended on the life stage with larger specimens ingesting more and larger microplastics. The presence of natural particles generally reduced the microplastics uptake. Our results demonstrate that freshwater invertebrates have the capacity to ingest microplastics. However, the quantity of uptake depends on their feeding type and morphology as well as on the availability of microplastics.

Manipulative parasites may not alter intermediate host distribution but still enhance their transmission: field evidence for increased vulnerability to definitive hosts and non-host predator avoidance.

PubMed

Lagrue, C; Güvenatam, A; Bollache, L

2013-02-01

Behavioural alterations induced by parasites in their intermediate hosts can spatially structure host populations, possibly resulting in enhanced trophic transmission to definitive hosts. However, such alterations may also increase intermediate host vulnerability to non-host predators. Parasite-induced behavioural alterations may thus vary between parasite species and depend on each parasite definitive host species. We studied the influence of infection with 2 acanthocephalan parasites (Echinorhynchus truttae and Polymorphus minutus) on the distribution of the amphipod Gammarus pulex in the field. Predator presence or absence and predator species, whether suitable definitive host or dead-end predator, had no effect on the micro-distribution of infected or uninfected G. pulex amphipods. Although neither parasite species seem to influence intermediate host distribution, E. truttae infected G. pulex were still significantly more vulnerable to predation by fish (Cottus gobio), the parasite's definitive hosts. In contrast, G. pulex infected with P. minutus, a bird acanthocephalan, did not suffer from increased predation by C. gobio, a predator unsuitable as host for P. minutus. These results suggest that effects of behavioural changes associated with parasite infections might not be detectable until intermediate hosts actually come in contact with predators. However, parasite-induced changes in host spatial distribution may still be adaptive if they drive hosts into areas of high transmission probabilities.

Microplastic Effect Thresholds for Freshwater Benthic Macroinvertebrates

PubMed Central

2018-01-01

Now that microplastics have been detected in lakes, rivers, and estuaries all over the globe, evaluating their effects on biota has become an urgent research priority. This is the first study that aims at determining the effect thresholds for a battery of six freshwater benthic macroinvertebrates with different species traits, using a wide range of microplastic concentrations. Standardized 28 days single species bioassays were performed under environmentally relevant exposure conditions using polystyrene microplastics (20–500 μm) mixed with sediment at concentrations ranging from 0 to 40% sediment dry weight (dw). Microplastics caused no effects on the survival of Gammarus pulex, Hyalella azteca, Asellus aquaticus, Sphaerium corneum, and Tubifex spp. and no effects were found on the reproduction of Lumbriculus variegatus. No significant differences in growth were found for H. azteca, A. aquaticus, S. corneum, L. variegatus, and Tubifex spp. However, G. pulex showed a significant reduction in growth (EC10 = 1.07% sediment dw) and microplastic uptake was proportional with microplastic concentrations in sediment. These results indicate that although the risks of environmentally realistic concentrations of microplastics may be low, they still may affect the biodiversity and the functioning of aquatic communities which after all also depend on the sensitive species. PMID:29337537

The effects of motorway runoff on freshwater ecosystems. 2: Identifying major toxicants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maltby, L.; Boxall, A.B.A.; Forrow, D.M.

1995-06-01

Previous studies have provided prima facie evidence that runoff from the M1 motorway, UK, affects both the quality of the receiving water and the biota living there, in sites short distances from point sources-i.e., possible worst-case situations. Because discharges contain a wide variety of contaminants, both the identification of toxicants and the establishment of causal relationships between observed changes in water/sediment quality and biology are often difficult. In this particular case, the problem was addressed by conducting a series of toxicity tests using the benthic amphipod Gammarus pulex. The abundance of this species was greatly reduced downstream of the pointmore » where motorway runoff entered the stream. Stream water contaminated with motorway runoff was not toxic to G. pulex. However, exposure to contaminated sediments resulted in a slight reduction in survival over 14 d, and sediment manipulation experiments identified hydrocarbons, copper, and zinc as potential toxicants. Spiking experiments confirmed the importance of hydrocarbons, and fractionation studies indicated that most of the observed toxicity was due to the fraction containing polycyclic aromatic hydrocarbons. Animals exposed to contaminated sediments and water spiked with sediment extract accumulated aromatic hydrocarbons in direct proportion to exposure concentrations.« less

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

2016-03-01

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.

Modelling survival: exposure pattern, species sensitivity and uncertainty.

PubMed

Ashauer, Roman; Albert, Carlo; Augustine, Starrlight; Cedergreen, Nina; Charles, Sandrine; Ducrot, Virginie; Focks, Andreas; Gabsi, Faten; Gergs, André; Goussen, Benoit; Jager, Tjalling; Kramer, Nynke I; Nyman, Anna-Maija; Poulsen, Veronique; Reichenberger, Stefan; Schäfer, Ralf B; Van den Brink, Paul J; Veltman, Karin; Vogel, Sören; Zimmer, Elke I; Preuss, Thomas G

2016-07-06

The General Unified Threshold model for Survival (GUTS) integrates previously published toxicokinetic-toxicodynamic models and estimates survival with explicitly defined assumptions. Importantly, GUTS accounts for time-variable exposure to the stressor. We performed three studies to test the ability of GUTS to predict survival of aquatic organisms across different pesticide exposure patterns, time scales and species. Firstly, using synthetic data, we identified experimental data requirements which allow for the estimation of all parameters of the GUTS proper model. Secondly, we assessed how well GUTS, calibrated with short-term survival data of Gammarus pulex exposed to four pesticides, can forecast effects of longer-term pulsed exposures. Thirdly, we tested the ability of GUTS to estimate 14-day median effect concentrations of malathion for a range of species and use these estimates to build species sensitivity distributions for different exposure patterns. We find that GUTS adequately predicts survival across exposure patterns that vary over time. When toxicity is assessed for time-variable concentrations species may differ in their responses depending on the exposure profile. This can result in different species sensitivity rankings and safe levels. The interplay of exposure pattern and species sensitivity deserves systematic investigation in order to better understand how organisms respond to stress, including humans.

Predatory functional response and prey choice identify predation differences between native/invasive and parasitised/unparasitised crayfish.

PubMed

Haddaway, Neal R; Wilcox, Ruth H; Heptonstall, Rachael E A; Griffiths, Hannah M; Mortimer, Robert J G; Christmas, Martin; Dunn, Alison M

2012-01-01

Invasive predators may change the structure of invaded communities through predation and competition with native species. In Europe, the invasive signal crayfish Pacifastacus leniusculus is excluding the native white clawed crayfish Austropotamobius pallipes. This study compared the predatory functional responses and prey choice of native and invasive crayfish and measured impacts of parasitism on the predatory strength of the native species. Invasive crayfish showed a higher (>10%) prey (Gammarus pulex) intake rate than (size matched) natives, reflecting a shorter (16%) prey handling time. The native crayfish also showed greater selection for crustacean prey over molluscs and bloodworm, whereas the invasive species was a more generalist predator. A. pallipes parasitised by the microsporidian parasite Thelohania contejeani showed a 30% reduction in prey intake. We suggest that this results from parasite-induced muscle damage, and this is supported by a reduced (38%) attack rate and increased (30%) prey handling time. Our results indicate that the per capita (i.e., functional response) difference between the species may contribute to success of the invader and extinction of the native species, as well as decreased biodiversity and biomass in invaded rivers. In addition, the reduced predatory strength of parasitized natives may impair their competitive abilities, facilitating exclusion by the invader.

Limiting immunopathology: Interaction between carotenoids and enzymatic antioxidant defences.

PubMed

Babin, A; Saciat, C; Teixeira, M; Troussard, J-P; Motreuil, S; Moreau, J; Moret, Y

2015-04-01

The release of reactive oxygen and nitrogen species (ROS and RNS) during the inflammatory response generates damages to host tissues, referred to as immunopathology, and is an important factor in ecological immunology. The integrated antioxidant system, comprising endogenous antioxidant enzymes (e.g. superoxide dismutase SOD, and catalase CAT) and dietary antioxidants (e.g. carotenoids), helps to cope with immune-mediated oxidative stress. Crustaceans store large amounts of dietary carotenoids for yet unclear reasons. While being immunostimulants and antioxidants, the interaction of these pigments with antioxidant enzymes remains unclear. Here, we tested the interaction between dietary supplementation with carotenoids and immune challenge on immune defences and the activity of the antioxidant enzymes SOD and CAT, in the amphipod crustacean Gammarus pulex. Dietary supplementation increased the concentrations of circulating carotenoids and haemocytes in the haemolymph, while the immune response induced the consumption of circulating carotenoids and a drop of haemocyte density. Interestingly, supplemented gammarids exhibited down-regulated SOD activity but high CAT activity compared to control ones. Our study reveals specific interactions of dietary carotenoids with endogenous antioxidant enzymes, and further underlines the potential importance of carotenoids in the evolution of immunity and/or of antioxidant mechanisms in crustaceans. Copyright © 2014 Elsevier Ltd. All rights reserved.

Role of cellular compartmentalization in the trophic transfer of mercury species in a freshwater plant-crustacean food chain.

PubMed

Beauvais-Flück, Rebecca; Chaumot, Arnaud; Gimbert, Frédéric; Quéau, Hervé; Geffard, Olivier; Slaveykova, Vera I; Cosio, Claudia

2016-12-15

Mercury (Hg) represents an important risk for human health through the food webs contamination. Macrophytes bioaccumulate Hg and play a role in Hg transfer to food webs in shallow aquatic ecosystems. Nevertheless, the compartmentalization of Hg within macrophytes, notably major accumulation in the cell wall and its impact on trophic transfer to primary consumers are overlooked. The present work focusses on the trophic transfer of inorganic Hg (IHg) and monomethyl-Hg (MMHg) from the intracellular and cell wall compartments of the macrophyte Elodea nuttallii - considered a good candidate for phytoremediation - to the crustacean Gammarus fossarum. The results demonstrated that Hg accumulated in both compartments was trophically bioavailable to gammarids. Besides IHg from both compartments were similarly transferred to G. fossarum, while for MMHg, uptake rates were ∼2.5-fold higher in G. fossarum fed with the cell wall vs the intracellular compartment. During the depuration phase, Hg concentrations in G. fossarum varied insignificantly suggesting that both IHg and MMHg were strongly bound to biological ligands in the crustacean. Our data imply that cell walls have to be considered as an important source of Hg to consumers in freshwater food webs when developing procedures for enhancing aquatic environment protection during phytoremediation programs. Copyright © 2016 Elsevier B.V. All rights reserved.

Cuticles of European and American lobsters harbor diverse bacterial species and differ in disease susceptibility.

PubMed

Whitten, Miranda M A; Davies, Charlotte E; Kim, Anita; Tlusty, Michael; Wootton, Emma C; Chistoserdov, Andrei; Rowley, Andrew F

2014-06-01

Diseases of lobster shells have a significant impact on fishing industries but the risk of disease transmission between different lobster species has yet to be properly investigated. This study compared bacterial biofilm communities from American (Homarus americanus) and European lobsters (H. gammarus), to assess both healthy cuticle and diseased cuticle during lesion formation. Culture-independent molecular techniques revealed diversity in the bacterial communities of cuticle biofilms both within and between the two lobster species, and identified three bacterial genera associated with shell lesions plus two putative beneficial bacterial species (detected exclusively in healthy cuticle or healing damaged cuticle). In an experimental aquarium shared between American and European lobsters, heterospecific transmission of potentially pathogenic bacteria appeared to be very limited; however, the claws of European lobsters were more likely to develop lesions when reared in the presence of American lobsters. Aquarium biofilms were also examined but revealed no candidate pathogens for environmental transmission. Aquimarina sp. 'homaria' (a potential pathogen associated with a severe epizootic form of shell disease) was detected at a much higher prevalence among American than European lobsters, but its presence correlated more with exacerbation of existing lesions rather than with lesion initiation. © 2014 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Effects of lambda-cyhalothrin in two ditch microcosm systems of different trophic status.

PubMed

Roessink, Ivo; Arts, Gertie H P; Belgers, J Dick M; Bransen, Fred; Maund, Steve J; Brock, Theo C M

2005-07-01

The fate and effects of the pyrethroid insecticide lambda-cyhalothrin were compared in mesotrophic (macrophyte-dominated) and eutrophic (phytoplankton-dominated) ditch microcosms (approximately 0.5 m3). Lambda-cyhalothrin was applied three times at one-week intervals at concentrations of 10, 25, 50, 100, and 250 ng/L. The rate of dissipation of lambda-cyhalothrin in the water column of the two types of test systems was similar. After 1 d, only 30% of the amount applied remained in the water phase. Initial, direct effects were observed primarily on arthropod taxa. The most sensitive species was the phantom midge (Chaoborus obscuripes). Threshold levels for slight and transient direct toxic effects were similar (10 ng/L) between types of test systems. At treatment levels of 25 ng/L and higher, apparent population and community responses occurred. At treatments of 100 and 250 ng/L, the rate of recovery of the macroinvertebrate community was lower in the macrophyte-dominated systems, primarily because of a prolonged decline of the amphipod Gammarus pulex. This species occurred at high densities only in the macrophyte-dominated enclosures. Indirect effects (e.g., increase of rotifers and microcrustaceans) were more pronounced in the plankton-dominated test systems, particularly at treatment levels of 25 ng/L and higher.

Macroinvertebrate community response to pulse exposure with the insecticide lambda-cyhalothrin using in-stream mesocosms.

PubMed

Heckmann, Lars-Henrik; Friberg, Nikolai

2005-03-01

Pesticides are constantly being applied to agricultural catchments, but little is known about their impact on aquatic biota during natural exposure. In the present study, the impact of the pyrethroid lambda-cyhalothrin was studied in an in-stream mesocosm setup. Twice during the summer of 2002, the natural macroinvertebrate community was exposed in situ to a 30-min pulse of lambda-cyhalothrin. Pyrethroid doses were released through a modified drip set with nominal concentrations of 0.10, 1.00, and 10.0 microg L(-1) during the first exposure and 0.05, 0.50, and 5.00 microg L(-1) in the second exposure. Before, during, and after exposure, drifting macroinvertebrates were caught in nets. Quantitative benthic samples were taken both before and on two occasions after exposure. Macroinvertebrate drift increased immediately after the pulse exposure, with total drift being significantly higher at all concentrations. Gammarus pulex, various Ephemeroptera, Leuctra sp., and Simuliidae were some of the taxa showing the most pronounced drift response. Structural change in the community was found only at 5.00 and 10.0 microg L(-1), and recovery occurred within approximately two weeks. The present study may be valuable in assessing extrapolations based on laboratory results as well as in evaluating pyrethroid impact on natural freshwater environments.

Adaptive Sex Determination and Population Dynamics in a Brackish-water Amphipod

NASA Astrophysics Data System (ADS)

Watt, Penelope J.; Adams, Jonathan

1993-09-01

Gammarus duebeni is a sexually dimorphic amphipod with an unusual and environmentally mediated sex determining system. In seasonal populations, environmental sex determination (ESD) is selectively advantageous and males and females are produced at different times of the year, but it has been predicted that where generations overlap or the breeding season is long, ESD should no longer have a selective advantage over genetic mechanisms of sex determination and males and females should be produced simultaneously. The dynamics of a supposedly bivoltine population at Totton Marsh on the south coast of England were investigated. The field study showed that the breeding season at Totton was not in fact bivoltine but long, extending through most of the year with a short break in early summer. Population sex ratio fluctuated seasonally: this pattern appears to be the product of differences in production of males and females rather than growth or mortality. Thus, contrary to expectations, ESD does occur in this population. Photoperiod is the cue for sex determination in the laboratory, but in the field this alone could not account for the observed pattern of male and female production at Totton Marsh. Another major variable must be involved and it is proposed that it also has an influence on other G. duebeni populations.

Metal accumulation by an epigean and a hypogean freshwater amphipod: Considerations for water quality assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pienet, S.

1999-12-01

To evaluate their potential as biomonitors of surface and underground water quality, the accumulation of essential metals, zinc and copper, by two species of amphipod crustaceans, Gammarus fossarum (an epigean amphipod) and Niphargus rhenorhodanensis (a similar but blind and hypogean form) was investigated. These two species were exposed, under controlled laboratory conditions, to different metal concentrations for 12 days. Several concentrations of each of the two metals separately and one concentration of a mixture of both were tested. Percent mortality revealed that the hypogean species was more resistant than the epigean. During the 12 days of experiment, accumulation patterns differedmore » between species and between metals. G. fossarum, but not N. rhenorhodanensis, accumulated zinc at exposures of up to 12 days and concentrations as great as 1,000 {micro}g/L. Zinc levels in tissue of G. fossarum were greater than in those of N. rhenorhodanensis. Epigean and hypogean amphipods did not clearly accumulate copper in exposures as great at 65 {micro}g/L. Possible reasons for the differences in zinc and copper accumulation between the two species are discussed. Finally, the suitability of the two species as biomonitors for surface and underground water is discussed.« less

Microplastic Effect Thresholds for Freshwater Benthic Macroinvertebrates.

PubMed

Redondo-Hasselerharm, Paula E; Falahudin, Dede; Peeters, Edwin T H M; Koelmans, Albert A

2018-02-20

Now that microplastics have been detected in lakes, rivers, and estuaries all over the globe, evaluating their effects on biota has become an urgent research priority. This is the first study that aims at determining the effect thresholds for a battery of six freshwater benthic macroinvertebrates with different species traits, using a wide range of microplastic concentrations. Standardized 28 days single species bioassays were performed under environmentally relevant exposure conditions using polystyrene microplastics (20-500 μm) mixed with sediment at concentrations ranging from 0 to 40% sediment dry weight (dw). Microplastics caused no effects on the survival of Gammarus pulex, Hyalella azteca, Asellus aquaticus, Sphaerium corneum, and Tubifex spp. and no effects were found on the reproduction of Lumbriculus variegatus. No significant differences in growth were found for H. azteca, A. aquaticus, S. corneum, L. variegatus, and Tubifex spp. However, G. pulex showed a significant reduction in growth (EC 10 = 1.07% sediment dw) and microplastic uptake was proportional with microplastic concentrations in sediment. These results indicate that although the risks of environmentally realistic concentrations of microplastics may be low, they still may affect the biodiversity and the functioning of aquatic communities which after all also depend on the sensitive species.

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.

Temperature rise and parasitic infection interact to increase the impact of an invasive species.

PubMed

Laverty, Ciaran; Brenner, David; McIlwaine, Christopher; Lennon, Jack J; Dick, Jaimie T A; Lucy, Frances E; Christian, Keith A

2017-04-01

Invasive species often detrimentally impact native biota, e.g. through predation, but predicting such impacts is difficult due to multiple and perhaps interacting abiotic and biotic context dependencies. Higher mean and peak temperatures, together with parasites, might influence the impact of predatory invasive host species additively, synergistically or antagonistically. Here, we apply the comparative functional response methodology (relationship between resource consumption rate and resource supply) in one experiment and conduct a second scaled-up mesocosm experiment to assess any differential predatory impacts of the freshwater invasive amphipod Gammarus pulex, when uninfected and infected with the acanthocephalan Echinorhynchus truttae, at three temperatures representative of current and future climate. Individual G. pulex showed Type II predatory functional responses. In both experiments, infection was associated with higher maximum feeding rates, which also increased with increasing temperatures. Additionally, infection interacted with higher temperatures to synergistically elevate functional responses and feeding rates. Parasitic infection also generally increased Q 10 values. We thus suggest that the differential metabolic responses of the host and parasite to increasing temperatures drives the synergy between infection and temperature, elevating feeding rates and thus enhancing the ecological impact of the invader. Copyright © 2017 Australian Society for Parasitology. Published by Elsevier Ltd. All rights reserved.

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

Growth and reproductive performance by different feed types in fresh water angelfish (Pterophyllum scalare Schultze, 1823)

PubMed Central

Kasiri, Milad; Farahi, Amin; Sudagar, Mohammad

2012-01-01

It is well established that reproduction is sensitive to the state of energy reserves, and that there is a balance between energy homeostasis and fertility. In this view, this study examined the effects of different diets on growth and reproductive performance of fresh water angelfish. Twenty four pairs of angelfish (weighing 3.58 ± 0.24 g) were fed with four types of diets including live earth worm (LEW), dried Tubifex (DT), dried Gammarus (DG) and prepared granulated feed (PGF), twice a day for 90 days. Reproductive parameters were measured between days 60 and 90. The significant increase in the gonadosomatic index (GSI), fecundity and hatchability brought about by the LEW were demonstrated by the higher number of spawned eggs and hatched larvae. The best growth observed significantly in PGF, and length of larvae was enhanced in this group, consequently. The numbers of dead and deformed fry were lower in the fish fed with PGF and LEW, but there was no significant difference among experimental groups. This study showed that breeders benefit from inclusion of prepared granulated feed and living earth worm during their growth and reproductive stages, and simultaneous using of them for achieving better results is suggested. PMID:25610565

Modelling survival: exposure pattern, species sensitivity and uncertainty

PubMed Central

Ashauer, Roman; Albert, Carlo; Augustine, Starrlight; Cedergreen, Nina; Charles, Sandrine; Ducrot, Virginie; Focks, Andreas; Gabsi, Faten; Gergs, André; Goussen, Benoit; Jager, Tjalling; Kramer, Nynke I.; Nyman, Anna-Maija; Poulsen, Veronique; Reichenberger, Stefan; Schäfer, Ralf B.; Van den Brink, Paul J.; Veltman, Karin; Vogel, Sören; Zimmer, Elke I.; Preuss, Thomas G.

2016-01-01

The General Unified Threshold model for Survival (GUTS) integrates previously published toxicokinetic-toxicodynamic models and estimates survival with explicitly defined assumptions. Importantly, GUTS accounts for time-variable exposure to the stressor. We performed three studies to test the ability of GUTS to predict survival of aquatic organisms across different pesticide exposure patterns, time scales and species. Firstly, using synthetic data, we identified experimental data requirements which allow for the estimation of all parameters of the GUTS proper model. Secondly, we assessed how well GUTS, calibrated with short-term survival data of Gammarus pulex exposed to four pesticides, can forecast effects of longer-term pulsed exposures. Thirdly, we tested the ability of GUTS to estimate 14-day median effect concentrations of malathion for a range of species and use these estimates to build species sensitivity distributions for different exposure patterns. We find that GUTS adequately predicts survival across exposure patterns that vary over time. When toxicity is assessed for time-variable concentrations species may differ in their responses depending on the exposure profile. This can result in different species sensitivity rankings and safe levels. The interplay of exposure pattern and species sensitivity deserves systematic investigation in order to better understand how organisms respond to stress, including humans. PMID:27381500

Modelling survival: exposure pattern, species sensitivity and uncertainty

NASA Astrophysics Data System (ADS)

Ashauer, Roman; Albert, Carlo; Augustine, Starrlight; Cedergreen, Nina; Charles, Sandrine; Ducrot, Virginie; Focks, Andreas; Gabsi, Faten; Gergs, André; Goussen, Benoit; Jager, Tjalling; Kramer, Nynke I.; Nyman, Anna-Maija; Poulsen, Veronique; Reichenberger, Stefan; Schäfer, Ralf B.; van den Brink, Paul J.; Veltman, Karin; Vogel, Sören; Zimmer, Elke I.; Preuss, Thomas G.

2016-07-01

The General Unified Threshold model for Survival (GUTS) integrates previously published toxicokinetic-toxicodynamic models and estimates survival with explicitly defined assumptions. Importantly, GUTS accounts for time-variable exposure to the stressor. We performed three studies to test the ability of GUTS to predict survival of aquatic organisms across different pesticide exposure patterns, time scales and species. Firstly, using synthetic data, we identified experimental data requirements which allow for the estimation of all parameters of the GUTS proper model. Secondly, we assessed how well GUTS, calibrated with short-term survival data of Gammarus pulex exposed to four pesticides, can forecast effects of longer-term pulsed exposures. Thirdly, we tested the ability of GUTS to estimate 14-day median effect concentrations of malathion for a range of species and use these estimates to build species sensitivity distributions for different exposure patterns. We find that GUTS adequately predicts survival across exposure patterns that vary over time. When toxicity is assessed for time-variable concentrations species may differ in their responses depending on the exposure profile. This can result in different species sensitivity rankings and safe levels. The interplay of exposure pattern and species sensitivity deserves systematic investigation in order to better understand how organisms respond to stress, including humans.

Health effects of metoprolol in epibenthic and endobenthic invertebrates-A basis to validate future in vitro biotests for effect-based biomonitoring.

PubMed

Jungmann, Dirk; Berg, Kristin; Dieterich, Andreas; Frank, Martin; Gräf, Tonya; Scheurer, Marco; Schwarz, Simon; Siewert, Carmen; Oetken, Matthias

2017-02-23

The aim of this study was to determine the effect data for metoprolol as a model substance for beta-blockers in aquatic invertebrates. The results will be used as a basis for the validation of future mode of action-based in vitro test systems targeting this class of pharmaceuticals. Effects of metoprolol were investigated in two autochthonous species with high relevance in stream ecology: the amphipod Gammarus fossarum and the oligochaete Lumbriculus variegatus. Mortality in G. fossarum was not observed in acute toxicity testing (48 h), and a significant increase of mortality at 45 mg/L was found when amphipods were exposed chronically (40 days). The most sensitive population-relevant endpoints were the juvenile-adult ratio and number of egg-bearing females with NOEC/LOEC-values of 5/15 mg/L. No proteotoxic effects were identified in G. fossarum. The sediment toxicity test with L. variegatus according to the OECD Guideline 225 with an exposure time of 28 days resulted in EC 10 -values of 92.5 and 126.1 mg/kg dw for the endpoints reproduction and biomass, respectively. In L. variegatus the response kinetics of Hsp70 showed no significant difference between the treatments. A tendency for rising lipid peroxide concentrations was found between 0.03 and 10 mg/kg dw , which were significant between the treatments, but not to the control.

Does temporal variation of mercury levels in Arctic seabirds reflect changes in global environmental contamination, or a modification of Arctic marine food web functioning?

PubMed

Fort, Jérôme; Grémillet, David; Traisnel, Gwendoline; Amélineau, Françoise; Bustamante, Paco

2016-04-01

Studying long-term trends of contaminants in Arctic biota is essential to better understand impacts of anthropogenic activities and climate change on the exposure of sensitive species and marine ecosystems. We concurrently measured temporal changes (2006-2014) in mercury (Hg) contamination of little auks (Alle alle; the most abundant Arctic seabird) and in their major zooplankton prey species (Calanoid copepods, Themisto libellula, Gammarus spp.). We found an increasing contamination of the food-chain in East Greenland during summer over the last decade. More specifically, bird contamination (determined by body feather analyses) has increased at a rate of 3.4% per year. Conversely, bird exposure to Hg during winter in the northwest Atlantic (determined by head feather analyses) decreased over the study period (at a rate of 1.5% per year), although winter concentrations remained consistently higher than during summer. By combining mercury levels measured in birds and zooplankton to isotopic analyses, our results demonstrate that inter-annual variations of Hg levels in little auks reflect changes in food-chain contamination, rather than a reorganization of the food web and a modification of seabird trophic ecology. They therefore underline the value of little auks, and Arctic seabirds in general, as bio-indicators of long-term changes in environmental contamination. Copyright © 2015 Elsevier Ltd. All rights reserved.

Lobster and cod benefit from small-scale northern marine protected areas: inference from an empirical before–after control-impact study

PubMed Central

Moland, Even; Olsen, Esben Moland; Knutsen, Halvor; Garrigou, Pauline; Espeland, Sigurd Heiberg; Kleiven, Alf Ring; André, Carl; Knutsen, Jan Atle

2013-01-01

Marine protected areas (MPAs) are increasingly implemented as tools to conserve and manage fisheries and target species. Because there are opportunity costs to conservation, there is a need for science-based assessment of MPAs. Here, we present one of the northernmost documentations of MPA effects to date, demonstrated by a replicated before–after control-impact (BACI) approach. In 2006, MPAs were implemented along the Norwegian Skagerrak coast offering complete protection to shellfish and partial protection to fish. By 2010, European lobster (Homarus gammarus) catch-per-unit-effort (CPUE) had increased by 245 per cent in MPAs, whereas CPUE in control areas had increased by 87 per cent. Mean size of lobsters increased by 13 per cent in MPAs, whereas increase in control areas was negligible. Furthermore, MPA-responses and population development in control areas varied significantly among regions. This illustrates the importance of a replicated BACI design for reaching robust conclusions and management decisions. Partial protection of Atlantic cod (Gadus morhua) was followed by an increase in population density and body size compared with control areas. By 2010, MPA cod were on average 5 cm longer than in any of the control areas. MPAs can be useful management tools in rebuilding and conserving portions of depleted lobster populations in northern temperate waters, and even for a mobile temperate fish species such as the Atlantic cod. PMID:23303544

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

Impact of lambda-cyhalothrin on a macroinvertebrate assemblage in outdoor experimental channels: implications for ecosystem functioning.

PubMed

Rasmussen, Jes Jessen; Friberg, Nikolai; Larsen, Soren E

2008-11-21

In this study, the impact of a single pulse of the pyrethroid lambda-cyhalothrin was tested on a macroinvertebrate assemblage consisting of Gammarus pulex, Leuctra nigra, Heptagenia sulphurea and Ancylus fluviatilis in outdoor experimental stream channels. Channels (4m long, 0.1m wide) were groundwater fed and had natural substratum. Macroinvertebrates were exposed to 10.65 or 106.5 ng L(-1) lambda cyhalothrin for 90 min in the laboratory and after 24h introduced to the experimental stream channels with four replicates of each treatment and controls. Drift samples were taken with 24-h interval for 10 days and behaviour of drifted macroinvertebrates was assessed. Microalgae biomass was measured on days 1, 5, 8 and 10 along with leaf litter decomposition using leaf packs of beech (Fagus sylvatica). Numbers of drifting G. pulex and L. nigra with reduced mobility increased significantly with concentration of lambda-cyhalothrin. Increase of algal biomass was significantly greater in stream channels with macroinvertebrates exposed to 106.5 ng L(-1) compared to controls and 10.65 ng L(-1) treatments. Accrual of microalgal biomass was significantly higher in the high concentration treatment and decomposition of leaf litter was significantly greater in control channels compared to channels with exposed macroinvertebrates. This study may apply valuable knowledge to the understanding and assessment of how pyrethroids impact ecosystem functioning in streams.

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.

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

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. © 2013 Elsevier B.V. All rights reserved.

Multiple stress response of lowland stream benthic macroinvertebrates depends on habitat type.

PubMed

Graeber, Daniel; Jensen, Tinna M; Rasmussen, Jes J; Riis, Tenna; Wiberg-Larsen, Peter; Baattrup-Pedersen, Annette

2017-12-01

Worldwide, lowland stream ecosystems are exposed to multiple anthropogenic stress due to the combination of water scarcity, eutrophication, and fine sedimentation. The understanding of the effects of such multiple stress on stream benthic macroinvertebrates has been growing in recent years. However, the interdependence of multiple stress and stream habitat characteristics has received little attention, although single stressor studies indicate that habitat characteristics may be decisive in shaping the macroinvertebrate response. We conducted an experiment in large outdoor flumes to assess the effects of low flow, fine sedimentation, and nutrient enrichment on the structure of the benthic macroinvertebrate community in riffle and run habitats of lowland streams. For most taxa, we found a negative effect of low flow on macroinvertebrate abundance in the riffle habitat, an effect which was mitigated by fine sedimentation for overall community composition and the dominant shredder species (Gammarus pulex) and by nutrient enrichment for the dominant grazer species (Baetis rhodani). In contrast, fine sediment in combination with low flow rapidly affected macroinvertebrate composition in the run habitat, with decreasing abundances of many species. We conclude that the effects of typical multiple stressor scenarios on lowland stream benthic macroinvertebrates are highly dependent on habitat conditions and that high habitat diversity needs to be given priority by stream managers to maximize the resilience of stream macroinvertebrate communities to multiple stress. Copyright © 2017 Elsevier B.V. All rights reserved.

Parasite transfer from crustacean to fish hosts in the Lübeck Bight, SW Baltic Sea

NASA Astrophysics Data System (ADS)

Zander, C. D.; Groenewold, S.; Strohbach, U.

1994-03-01

Four helminth parasites out of 19 species found in the Lübeck Bight, Baltic Sea, were chosen for investigations on the transfer from invertebrate to small-sized fish hosts: larvae of the tapeworms Schistocephalus sp. and Bothriocephalus sp. (Cestoda) living in planktonic copepods as primary hosts; Podocotyle atomon (Digenea) and Hysterothylacium sp. (Nematoda) were found in benthic crustaceans, especially Gammarus spp. These hosts were the prey of 3 gobiid fishes, Gobiusculus flavescens (feeding mainly on plankton), Pomatoschistus minutus (preferring benthos), and P. pictus (feeding more on plankton than benthos). Because the fishes selected smaller sizes of crustaceans, they ingested all stages of the copepods but only the smaller-sized groups of gammarids which were often less infested by parasites. In order to evaluate the probability for a fish to be parasitized by a helminth, an infestation potential index (IP) was calculated. Podocotyle atomon and Hysterothylacium sp. revealed an IP which was far lower in gobies than expected when the prevalences of the previous hosts were taken into consideration. The IP of tapeworm larvae was mainly influenced by the feeding pressure of the gobiid predators, which might change with developmental stage and season. It is concluded that parasite transfer to the next host decreases when sizes of prey and predator differ only moderately. This mechanism can reduce the numbers of parasites transferred to less suitable or wrong hosts.

Interspecific interactions between brown trout and slimy sculpin in stream enclosures

USGS Publications Warehouse

Ruetz, C. R.; Hurford, A.L.; Vondracek, B.

2003-01-01

We conducted a 30-d manipulative experiment in Valley Creek, Minnesota, to examine interspecific interactions between juvenile brown trout Salmo trutta and adult slimy sculpin Cottus cognatus. We measured the instantaneous growth of each species in the presence and absence of the other in 1-m2 enclosures. We tested single-species (three slimy sculpins/m2 or three brown trout/m2) and combined-species (three sculpins/m2 and three trout/m2) combinations in each of six riffles. We placed a clay tile in each enclosure to evaluate the effects of fish combinations on benthic macroinvertebrates. Growth of brown trout was unaffected by the presence of slimy sculpins (P = 0.647, power [to detect 50% increase in growth] = 0.92), whereas slimy sculpin growth was less in the presence of brown trout (P = 0.038). Densities of total benthic macroinvertebrates, Chironomidae, Trichoptera, and Physa did not differ among fish combinations (P > 0.3). However, densities of Gammarus pseudolimnaeus were significantly less in the presence of brown trout irrespective of the presence of slimy sculpins (P = 0.024), which could be a causal factor underlying the interaction between brown trout and slimy sculpins. We found asymmetrical competition between brown trout and slimy sculpins in stream enclosures, with brown trout being the superior competitor. Nevertheless, the size of enclosures may have biased our results, making it more likely to detect an effect of brown trout on slimy sculpins than vice versa.

Parasite-mediated predation between native and invasive amphipods.

PubMed Central

MacNeil, Calum; Dick, Jaimie T A; Hatcher, Melanie J; Terry, Rebecca S; Smith, Judith E; Dunn, Alison M

2003-01-01

Parasites can structure biological communities directly through population regulation and indirectly by processes such as apparent competition. However, the role of parasites in the process of biological invasion is less well understood and mechanisms of parasite mediation of predation among hosts are unclear. Mutual predation between native and invading species is an important factor in determining the outcome of invasions in freshwater amphipod communities. Here, we show that parasites mediate mutual intraguild predation among native and invading species and may thereby facilitate the invasion process. We find that the native amphipod Gammarus duebeni celticus is host to a microsporidian parasite, Pleistophora sp. (new species), with a frequency of infection of 0-90%. However, the parasite does not infect three invading species, G. tigrinus, G. pulex and Crangonyx pseudogracilis. In field and laboratory manipulations, we show that the parasite exhibits cryptic virulence: the parasite does not affect host fitness in single-species populations, but virulence becomes apparent when the native and invading species interact. That is, infection has no direct effect on G. d. celticus survivorship, size or fecundity; however, in mixed-species experiments, parasitized natives show a reduced capacity to prey on the smaller invading species and are more likely to be preyed upon by the largest invading species. Thus, by altering dominance relationships and hierarchies of mutual predation, parasitism strongly influences, and has the potential to change, the outcome of biological invasions. PMID:12816645

The impact of coastal defence structures (tetrapods) on decapod crustaceans in the southern North Sea.

PubMed

Wehkamp, Stephanie; Fischer, Philipp

2013-12-01

Although the use of coastal defence structures is expected to increase, little is known about the ecological impact of such structures on the natural environment. In particular, the temporal and spatial patterns of communities in association with artificial substrate are still poorly understood. This study examined possible effects of experimental tetrapod fields on the decapod crustacean community in a subtidal hard-bottom area in the southern North Sea. We performed in situ studies in the fields and along transects oriented away from the tetrapod fields. Species composition and abundances were assessed before and after the introduction of the artificial material. The study revealed a significant decrease of smaller, less vagile species (Pisidia longicornis, Pilumnus hirtellus, Galathea squamifera) over the entire study area in the years following the tetrapod introduction. For 2 species, Hyas araneus and Homarus gammarus, the tetrapods appeared to be highly attractive as habitat and shelter because their abundance increased over time. No distinct spatial or temporal effects were observed for mobile predatory crabs, such as Cancer pagurus and Liocarcinus spp. The results of the study demonstrate that possible effects of artificial structures on macro-invertebrates in temperate hard-bottom areas are highly species-specific and depend on the size, lifestyle and ecological requirements of the species. This work highlights the importance of long-term studies. Our findings clearly indicate that more time is needed to distinguish between natural and anthropogenic influences on species distributions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of intra- and interspecific competition on the sensitivity of aquatic macroinvertebrates to carbendazim.

PubMed

Del Arco, Ana Isabel; Parra, Gema; Rico, Andreu; Van den Brink, Paul J

2015-10-01

The Ecological Risk Assessment of pesticides and other potentially toxic chemicals is generally based on toxicity data obtained from single-species laboratory experiments. In the field, however, contaminant effects are ubiquitously co-occurring with ecological interactions such as species competition and predation, which might influence the sensitivity of the individuals exposed to toxicants. The present experimental study investigated how intra- and interspecific competition influence the response of sensitive aquatic organisms to a pesticide. For this, the effects of the fungicide carbendazim were assessed on the mortality and growth of the snail Bithynia tentaculata and the crustacean Gammarus pulex under different levels of intraspecific and interspecific competition for a food resource. Interspecific competition was created by adding individuals of Radix peregra and Asellus aquaticus, respectively. The interaction of competition and carbendazim exposure significantly influenced B. tentaculata growth, however, combined effects on survival and immobility were considered transient and were less easily demonstrated. Positive influence of competition on G. pulex survival was observed under low-medium carbendazim concentrations and under medium-high density pressures, being partly related to cannibalistic and predation compensatory mechanisms, enhanced under food limiting conditions. This study shows that intra- and interspecific competition pressure may influence the response of sensitive aquatic organisms in a more complex way (positive, non-significant and negative effects were observed) than just increasing the sensitivity of the studied species, as has generally been hypothesized. Copyright © 2015 Elsevier Inc. All rights reserved.

The complete mitochondrial genome of the common sea slater, Ligia oceanica (Crustacea, Isopoda) bears a novel gene order and unusual control region features

PubMed Central

Kilpert, Fabian; Podsiadlowski, Lars

2006-01-01

Background Sequence data and other characters from mitochondrial genomes (gene translocations, secondary structure of RNA molecules) are useful in phylogenetic studies among metazoan animals from population to phylum level. Moreover, the comparison of complete mitochondrial sequences gives valuable information about the evolution of small genomes, e.g. about different mechanisms of gene translocation, gene duplication and gene loss, or concerning nucleotide frequency biases. The Peracarida (gammarids, isopods, etc.) comprise about 21,000 species of crustaceans, living in many environments from deep sea floor to arid terrestrial habitats. Ligia oceanica is a terrestrial isopod living at rocky seashores of the european North Sea and Atlantic coastlines. Results The study reveals the first complete mitochondrial DNA sequence from a peracarid crustacean. The mitochondrial genome of Ligia oceanica is a circular double-stranded DNA molecule, with a size of 15,289 bp. It shows several changes in mitochondrial gene order compared to other crustacean species. An overview about mitochondrial gene order of all crustacean taxa yet sequenced is also presented. The largest non-coding part (the putative mitochondrial control region) of the mitochondrial genome of Ligia oceanica is unexpectedly not AT-rich compared to the remainder of the genome. It bears two repeat regions (4× 10 bp and 3× 64 bp), and a GC-rich hairpin-like secondary structure. Some of the transfer RNAs show secondary structures which derive from the usual cloverleaf pattern. While some tRNA genes are putative targets for RNA editing, trnR could not be localized at all. Conclusion Gene order is not conserved among Peracarida, not even among isopods. The two isopod species Ligia oceanica and Idotea baltica show a similarly derived gene order, compared to the arthropod ground pattern and to the amphipod Parhyale hawaiiensis, suggesting that most of the translocation events were already present the last common

Long-term effects of fungicides on leaf-associated microorganisms and shredder populations-an artificial stream study.

PubMed

Zubrod, Jochen P; Englert, Dominic; Wolfram, Jakob; Rosenfeldt, Ricki R; Feckler, Alexander; Bundschuh, Rebecca; Seitz, Frank; Konschak, Marco; Baudy, Patrick; Lüderwald, Simon; Fink, Patrick; Lorke, Andreas; Schulz, Ralf; Bundschuh, Mirco

2017-08-01

Leaf litter is a major source of carbon and energy for stream food webs, while both leaf-decomposing microorganisms and macroinvertebrate leaf shredders can be affected by fungicides. Despite the potential for season-long fungicide exposure for these organisms, however, such chronic exposures have not yet been considered. Using an artificial stream facility, effects of a chronic (lasting up to 8 wk) exposure to a mixture of 5 fungicides (sum concentration 20 μg/L) on leaf-associated microorganisms and the key leaf shredder Gammarus fossarum were therefore assessed. While bacterial density and microorganism-mediated leaf decomposition remained unaltered, fungicide exposure reduced fungal biomass (≤71%) on leaves from day 28 onward. Gammarids responded to the combined stress from consumption of fungicide-affected leaves and waterborne exposure with a reduced abundance (≤18%), which triggered reductions in final population biomass (18%) and in the number of precopula pairs (≤22%) but could not fully explain the decreased leaf consumption (19%), lipid content (≤43%; going along with an altered composition of fatty acids), and juvenile production (35%). In contrast, fine particulate organic matter production and stream respiration were unaffected. Our results imply that long-term exposure of leaf-associated fungi and shredders toward fungicides may result in detrimental implications in stream food webs and impairments of detrital material fluxes. These findings render it important to understand decomposer communities' long-term adaptational capabilities to ensure that functional integrity is safeguarded. Environ Toxicol Chem 2017;36:2178-2189. © 2017 SETAC. © 2017 SETAC.

Biotic interactions affect the colonization behavior of aquatic detritivorous macroinvertebrates in a heterogeneous environment

NASA Astrophysics Data System (ADS)

Verschut, Thomas A.; Meineri, Eric; Basset, Alberto

2015-05-01

It has previously been suggested that macroinvertebrates actively search for suitable patches to colonize. However, it is not well understood how the spatial arrangement of patches can affect colonization rates. In this study, we determined the importance of the environmental factors (distance, connectivity and resource availability) for patch colonization in an experimental system using Gammarus aequicauda (Amphipoda), Lekanesphaera hookeri (Isopoda) and Ecrobia ventrosa (Gastropoda). Furthermore, we also assessed how the relative importance of each of these environmental factors differed in interactions between the three species. The single species experiments showed that distance was the most important factor for G. aequicauda and E. ventrosa. However, while E. ventrosa preferred patches close to the release point, G. aequicauda strongly preferred patches further from the release point. High resource availability was a strong determinant for the patch colonization of G. aequicauda and L. hookeri. Connectivity was only of moderate importance in the study system for L. hookeri and E. ventrosa. The effects of the environmental factors were strongly affected by interspecific interactions in the multispecies experiments. For G. aequicauda, the distance preference was lowered in the presence of E. ventrosa. Moreover, while for L. hookeri the effect of resource availability was ruled out by the species interactions, resource availability gained importance for E. ventrosa in the presence of any of the other species. Our results suggest a strong link between environmental factors and biotic interactions in the colonization of habitat patches and indicate that the effect of biotic interactions is especially important for species sharing similar traits.

The Application of DNA Barcodes for the Identification of Marine Crustaceans from the North Sea and Adjacent Regions

PubMed Central

Raupach, Michael J.; Barco, Andrea; Steinke, Dirk; Beermann, Jan; Laakmann, Silke; Mohrbeck, Inga; Neumann, Hermann; Kihara, Terue C.; Pointner, Karin; Radulovici, Adriana; Segelken-Voigt, Alexandra; Wesse, Christina; Knebelsberger, Thomas

2015-01-01

During the last years DNA barcoding has become a popular method of choice for molecular specimen identification. Here we present a comprehensive DNA barcode library of various crustacean taxa found in the North Sea, one of the most extensively studied marine regions of the world. Our data set includes 1,332 barcodes covering 205 species, including taxa of the Amphipoda, Copepoda, Decapoda, Isopoda, Thecostraca, and others. This dataset represents the most extensive DNA barcode library of the Crustacea in terms of species number to date. By using the Barcode of Life Data Systems (BOLD), unique BINs were identified for 198 (96.6%) of the analyzed species. Six species were characterized by two BINs (2.9%), and three BINs were found for the amphipod species Gammarus salinus Spooner, 1947 (0.4%). Intraspecific distances with values higher than 2.2% were revealed for 13 species (6.3%). Exceptionally high distances of up to 14.87% between two distinct but monophyletic clusters were found for the parasitic copepod Caligus elongatus Nordmann, 1832, supporting the results of previous studies that indicated the existence of an overlooked sea louse species. In contrast to these high distances, haplotype-sharing was observed for two decapod spider crab species, Macropodia parva Van Noort & Adema, 1985 and Macropodia rostrata (Linnaeus, 1761), underlining the need for a taxonomic revision of both species. Summarizing the results, our study confirms the application of DNA barcodes as highly effective identification system for the analyzed marine crustaceans of the North Sea and represents an important milestone for modern biodiversity assessment studies using barcode sequences. PMID:26417993

Do differences in sensitivity between native and invasive amphipods explain their coexistence in Lake Constance? A case study with lambda-cyhalothrin.

PubMed

Bundschuh, Mirco; Gergs, René; Schadt, Sebastian; Schulz, Ralf

2013-07-01

Invasive species are considered as one of the major threats for biodiversity worldwide. The Ponto-Caspian species Dikerogammarus villosus, for instance, spread throughout continental Europe and was recorded for the first time also within Lake Constance in 2003. Although D. villosus is a highly competitive species it was not capable of replacing the native Gammarus roeselii completely in this ecosystem, especially in the riparian zones of the highly agriculturally used island "Reichenau". As differences in pesticide sensitivity between both amphipod species may explain their distribution, the present study assessed the implication of the highly toxic pyrethroid lambda-cyhalothrin, which is authorized for application in the Lake Constance region, assuming the invasive species being more sensitive than the native one. However, both the feeding activity bioassays, which measured the leaf consumption over 7d (n=20), as well as the predation bioassay, which measured the predation rate upon Baetis nymphs in concert with the feeding activity on leaf material over 96 h (n=13), revealed an up to 5-fold higher tolerance of D. villosus towards lambda-cyhalothrin. These results suggest the investigated insecticide not being the trigger for the observed distribution pattern of both amphipod species. Hence, other factors like the diversity of habitat structures or the levels of ammonia may have facilitated the coexistence. Nevertheless, the present study uncovered a high leaf-shredding efficacy of the invasive species D. villosus suggesting that its role in the leaf decomposition process may have been underestimated in the past. Copyright © 2013 Elsevier Ltd. All rights reserved.

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. © 2015 John Wiley & Sons Ltd.

Dietary effects on fatty acid composition in muscle tissue of juvenile European eel, Anguilla anguilla (L.)

NASA Astrophysics Data System (ADS)

Prigge, Enno; Malzahn, Arne M.; Zumholz, Karsten; Hanel, Reinhold

2012-03-01

The role of intracontinental migration patterns of European eel ( Anguilla anguilla) receives more and more recognition in both ecological studies of the European eel and possible management measures, but small-scale patterns proved to be challenging to study. We experimentally investigated the suitability of fatty acid trophic markers to elucidate the utilization of feeding habitats. Eight groups of juvenile European eels were fed on eight different diets in a freshwater recirculation system at 20°C for 56 days. Three groups were fed on freshwater diets ( Rutilus rutilus, Chironomidae larvae, and Gammarus pulex) and four groups were reared on diets of a marine origin ( Clupea harengus, Crangon crangon, Mysis spec., and Euphausia superba) and one on commercial pellets used in eel aquaculture. Fatty acid composition (FAC) of diets differed significantly with habitat. FAC of eel muscle tissue seemed to be rather insensitive to fatty acids supplied with diet, but the general pattern of lower n3:n6 and EPA:ARA ratios in freshwater prey organisms could be traced in the respective eels. Multivariate statistics of the fatty acid composition of the eels resulted in two distinct groups representing freshwater and marine treatments. Results further indicate the capability of selectively restraining certain fatty acids in eel, as e.g. the n3:n6 ratio in all treatments was <4, regardless of dietary n3:n6. In future studies on wild eel, these measures can be used to elucidate the utilization of feeding habitats of individual European eel.

Miniature circulatory systems: A new exposure system for ecotoxicological effect assessments in riverine organisms.

PubMed

Feiner, Mona; Beggel, Sebastian; Geist, Juergen

2016-11-01

Long-term effect assessments in ecotoxicological investigations are important, yet there is a lack of suitable exposure systems for these experiments that can be used for riverine species. A cost-efficient miniature circulatory system was developed that was evaluated for its applicability in long-term exposures in 2 stream-dwelling species: brown trout (Salmo trutta) and an amphipod (Gammarus roeseli). In an egg-to-fry exposure of S. trutta, the toxicity of 2 reverse osmosis concentrates was investigated as examples. Control hatching rate of yolk sac fry was 75 ± 7% and thus complies with the Organisation for Economic Co-operation and Development validity criterion (≥66%). The reverse osmosis concentrates did not impair the hatching rate in any tested concentration. In G. roeseli, mortality rates remained below 20% during a 21-d cultivation, fulfilling the common validity criterion in ecotoxicological testing. Mortality was significantly lower when the species was fed with conditioned alder leaves instead of an artificial shrimp food. Finally, a toxicity test on G. roeseli using copper as the test substance revealed median lethal concentration (LC50) values of 156 μg/L after 96 h and 99 μg/L after 264 h, which is in line with literature findings using other accepted exposure units. In conclusion, the miniature circulatory system provides a novel and cost-efficient exposure system for long-term investigations on riverine species that may also be applicable for other species of fishes and macroinvertebrates. Environ Toxicol Chem 2016;35:2827-2833. © 2016 SETAC. © 2016 SETAC.

Response of invertebrates from the hyporheic zone of chalk rivers to eutrophication and land use.

PubMed

Pacioglu, Octavian; Moldovan, Oana Teodora

2016-03-01

Whereas the response of lotic benthic macroinvertebrates to different environmental stressors is a widespread practice nowadays in assessing the water and habitat quality, the use of hyporheic zone invertebrates is still in its infancy. In this study, classification and regression trees analysis were employed in order to assess the ecological requirements and the potential as bioindicators for the hyporheic zone invertebrates inhabiting four lowland chalk rivers (south England) with contrasting eutrophication levels (based on surface nitrate concentrations) and magnitude of land use (based on percentage of fine sediments load and median interstitial space). Samples of fauna, water and sediment were sampled twice, during low (summer) and high (winter) groundwater level, at depths of 20 and 35 cm. Certain groups of invertebrates (Glossosomatidae and Psychomyiidae caddisflies, and riffle beetles) proved to be good indicators of rural catchments, moderately eutrophic and with high fine sediment load. A diverse community dominated by microcrustaceans (copepods and ostracods) were found as good indicators of highly eutrophic urban streams, with moderate-high fine sediment load. However, the use of other taxonomic groups (e.g. chironomids, oligochaetes, nematodes, water mites and the amphipod Gammarus pulex), very widespread in the hyporheic zone of all sampled rivers, is of limited use because of their high tolerance to the analysed stressors. We recommend the use of certain taxonomic groups (comprising both meiofauna and macroinvertebrates) dwelling in the chalk hyporheic zone as indicators of eutrophication and colmation and, along with routine benthic sampling protocols, for a more comprehensive water and habitat quality assessment of chalk rivers.

The Application of DNA Barcodes for the Identification of Marine Crustaceans from the North Sea and Adjacent Regions.

PubMed

Raupach, Michael J; Barco, Andrea; Steinke, Dirk; Beermann, Jan; Laakmann, Silke; Mohrbeck, Inga; Neumann, Hermann; Kihara, Terue C; Pointner, Karin; Radulovici, Adriana; Segelken-Voigt, Alexandra; Wesse, Christina; Knebelsberger, Thomas

2015-01-01

During the last years DNA barcoding has become a popular method of choice for molecular specimen identification. Here we present a comprehensive DNA barcode library of various crustacean taxa found in the North Sea, one of the most extensively studied marine regions of the world. Our data set includes 1,332 barcodes covering 205 species, including taxa of the Amphipoda, Copepoda, Decapoda, Isopoda, Thecostraca, and others. This dataset represents the most extensive DNA barcode library of the Crustacea in terms of species number to date. By using the Barcode of Life Data Systems (BOLD), unique BINs were identified for 198 (96.6%) of the analyzed species. Six species were characterized by two BINs (2.9%), and three BINs were found for the amphipod species Gammarus salinus Spooner, 1947 (0.4%). Intraspecific distances with values higher than 2.2% were revealed for 13 species (6.3%). Exceptionally high distances of up to 14.87% between two distinct but monophyletic clusters were found for the parasitic copepod Caligus elongatus Nordmann, 1832, supporting the results of previous studies that indicated the existence of an overlooked sea louse species. In contrast to these high distances, haplotype-sharing was observed for two decapod spider crab species, Macropodia parva Van Noort & Adema, 1985 and Macropodia rostrata (Linnaeus, 1761), underlining the need for a taxonomic revision of both species. Summarizing the results, our study confirms the application of DNA barcodes as highly effective identification system for the analyzed marine crustaceans of the North Sea and represents an important milestone for modern biodiversity assessment studies using barcode sequences.

Effects of stream enclosures on drifting invertebrates and fish growth

USGS Publications Warehouse

Zimmerman, J.K.H.; Vondracek, B.

2006-01-01

Stream ecologists often use enclosure experiments to investigate predator-prey interactions and competition within and among fish species. The design of enclosures, manipulation of species densities, and method of replication may influence experimental results. We designed an experiment with enclosure cages (1 m2, 6-mm mesh) to examine the relative influence of fish size, density, and prey availability on growth of brown trout (Salmo trutta), brook trout (Salvelinus fontinalis), and slimy sculpin (Cottus cognatus) within enclosures in Valley Creek, Minnesota. In addition, we examined water flow and invertebrate drift entering enclosures and in open riffles to investigate whether enclosures reduced the supply of invertebrate prey. Growth of small (age-0) brook and brown trout was not influenced by fish density, but growth of larger (age-1) trout generally decreased as density increased. Sculpin growth was not related to fish size or density, but increased with mean size of invertebrates in the drift. Enclosures reduced water flow and tended to reduce invertebrate drift rate, although total drift rate (ind./min), total drift density (ind./m3), and mean size of invertebrates were not significantly different inside enclosures compared to adjacent stream riffles. Enclosures had no effect on drift rate or size of Gammarus pseudolimnaeus, the main prey item for trout and sculpin in Valley Creek. Overall, our analyses indicated that reductions of prey availability by enclosures did not influence fish growth. Trout growth may have been limited at larger sizes and densities because of increased activity costs of establishing and defending territories, whereas sculpin growth was related to availability of large prey, a factor not influenced by enclosures. ?? 2006 by The North American Benthological Society.

Responses of trophic structure and zooplankton community to salinity and temperature in Tibetan lakes: Implication for the effect of climate warming.

PubMed

Lin, Qiuqi; Xu, Lei; Hou, Juzhi; Liu, Zhengwen; Jeppesen, Erik; Han, Bo-Ping

2017-11-01

Warming has pronounced effects on lake ecosystems, either directly by increased temperatures or indirectly by a change in salinity. We investigated the current status of zooplankton communities and trophic structure in 45 Tibetan lakes along a 2300 m altitude and a 76 g/l salinity gradient. Freshwater to hyposaline lakes mainly had three trophic levels: phytoplankton, small zooplankton and fish/Gammarus, while mesosaline to hypersaline lakes only had two: phytoplankton and large zooplankton. Zooplankton species richness declined significantly with salinity, but did not relate with temperature. Furthermore, the decline in species richness with salinity in lakes with two trophic levels was much less abrupt than in lakes with three trophic levels. The structural variation of the zooplankton community depended on the length of the food chain, and was significantly explained by salinity as the critical environmental variable. The zooplankton community shifted from dominance of copepods and small cladoceran species in the lakes with low salinity and three trophic levels to large saline filter-feeding phyllopod species in those lakes with high salinity and two trophic levels. The zooplankton to phytoplankton biomass ratio was positively related with temperature in two-trophic-level systems and vice versa in three-trophic-level systems. As the Tibetan Plateau is warming about three times faster than the global average, our results imply that warming could have a considerable impact on the structure and function of Tibetan lake ecosystems, either via indirect effects of salinization/desalinization on species richness, composition and trophic structure or through direct effects of water temperature on trophic interactions. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

The effects of parasite age and intensity on variability in acanthocephalan-induced behavioural manipulation.

PubMed

Franceschi, Nathalie; Bauer, Alexandre; Bollache, Loïc; Rigaud, Thierry

2008-08-01

Numerous parasites with complex life cycles are able to manipulate the behaviour of their intermediate host in a way that increases their trophic transmission to the definitive host. Pomphorhynchus laevis, an acanthocephalan parasite, is known to reverse the phototactic behaviour of its amphipod intermediate host, Gammarus pulex, leading to an increased predation by fish hosts. However, levels of behavioural manipulation exhibited by naturally-infected gammarids are extremely variable, with some individuals being strongly manipulated whilst others are almost not affected by infection. To investigate parasite age and parasite intensity as potential sources of this variation, we carried out controlled experimental infections on gammarids using parasites from two different populations. We first determined that parasite intensity increased with exposure dose, but found no relationship between infection and host mortality. Repeated measures confirmed that the parasite alters host behaviour only when it reaches the cystacanth stage which is infective for the definitive host. They also revealed, we believe for the first time, that the older the cystacanth, the more it manipulates its host. The age of the parasite is therefore a major source of variation in parasite manipulation. The number of parasites within a host was also a source of variation. Manipulation was higher in hosts infected by two parasites than in singly infected ones, but above this intensity, manipulation did not increase. Since the development time of the parasite was also different according to parasite intensity (it was longer in doubly infected hosts than in singly infected ones, but did not increase more in multi-infected hosts), individual parasite fitness could depend on the compromise between development time and manipulation efficiency. Finally, the two parasite populations tested induced slightly different degrees of behavioural manipulation.

Density vs. disease: Crustaceans in a temperate marine protected area

NASA Astrophysics Data System (ADS)

Davies, C. E.; Johnson, A. F.; Wootton, E. C.; Greenwood, S.; Clark, K. F.; Vogan, C. L.; Rowley, A. F.

2016-02-01

Since the move towards an ecosystem-based approach in fisheries management, marine protected areas (MPAs) have become increasingly popular. Implementation, however, is somewhat contentious and as a result of their short history, effects are still widely unknown and understudied. Here, we investigated the health of brown crab Cancer pagurus and European lobster Homarus gammarus populations in the Lundy Island MPA after 7 years of no-take protection. Population parameters (size, sex, abundance), disease (shell disease, Hematodinium spp., gaffkaemia) and injury presence (a known precursor to disease) were assessed over two years in both an un-fished no-take zone (NTZ) and a fished refuge zone (RZ). There was a higher lobster density and larger lobsters in the NTZ compared with the RZ, but an opposite trend for crabs. The probability of shell disease increased notably in lobsters over the minimum landing size (MLS), in those displaying injury, and in males. Injury presence was higher in lobsters in the NTZ compared with the RZ and in those above the MLS. Gaffkaemia was detected in <1% of lobsters. The number of injured crabs increased significantly over the two years surveyed (12%), as did the prevalence of shell disease (15%). The probability of shell disease increased significantly for male crabs and for those missing limbs. Crabs below the MLS had an increased probability of being injured. Overall, the study demonstrates both positive and potentially negative effects of long-term NTZs. Recovering populations in NTZs may be more susceptible to disease as a result of increased injury through density-dependent interaction. This in turn may lead to increased disease infection. The findings highlight the necessity for long-term MPA management to include monitoring of population abundance, as well as secondary community change effects such as disease increase, both before and after implementation.

Comparison of macroinvertebrate-derived stream quality metrics between snag and riffle habitats

USGS Publications Warehouse

Stepenuck, K.F.; Crunkilton, R.L.; Bozek, Michael A.; Wang, L.

2008-01-01

We compared benthic macroinvertebrate assemblage structure at snag and riffle habitats in 43 Wisconsin streams across a range of watershed urbanization using a variety of stream quality metrics. Discriminant analysis indicated that dominant taxa at riffles and snags differed; Hydropsychid caddisflies (Hydropsyche betteni and Cheumatopsyche spp.) and elmid beetles (Optioservus spp. and Stenemlis spp.) typified riffles, whereas isopods (Asellus intermedius) and amphipods (Hyalella azteca and Gammarus pseudolimnaeus) predominated in snags. Analysis of covariance indicated that samples from snag and riffle habitats differed significantly in their response to the urbanization gradient for the Hilsenhoff biotic index (BI), Shannon's diversity index, and percent of filterers, shredders, and pollution intolerant Ephemeroptera, Plecoptera, and Trichoptera (EPT) at each stream site (p ??? 0.10). These differences suggest that although macroinvertebrate assemblages present in either habitat type are sensitive to detecting the effects of urbanization, metrics derived from different habitats should not be intermixed when assessing stream quality through biomonitoring. This can be a limitation to resource managers who wish to compare water quality among streams where the same habitat type is not available at all stream locations, or where a specific habitat type (i.e., a riffle) is required to determine a metric value (i.e., BI). To account for differences in stream quality at sites lacking riffle habitat, snag-derived metric values can be adjusted based on those obtained from riffles that have been exposed to the same level of urbanization. Comparison of nonlinear regression equations that related stream quality metric values from the two habitat types to percent watershed urbanization indicated that snag habitats had on average 30.2 fewer percent EPT individuals, a lower diversity index value than riffles, and a BI value of 0.29 greater than riffles. ?? 2008 American Water

Aquatic risk assessment of a realistic exposure to pesticides used in bulb crops: a microcosm study.

PubMed

van Wijngaarden, René P A; Cuppen, Jan G M; Arts, Gertie H P; Crum, Steven J H; van den Hoorn, Martin W; van den Brink, Paul J; Brock, Theo C M

2004-06-01

The fungicide fluazinam, the insecticide lambda-cyhalothrin, and the herbicides asulam and metamitron were applied to indoor freshwater microcosms (water volume approximately 0.6 m3). The treatment regime was based on a realistic application scenario in tulip cultivation. Concentrations of each pesticide were equal to 0%, 0.2%, 0.5%, 2%, and 5% spray drift emission of label-recommended rates. Contribution of compounds to the toxicity of the pesticide package was established by expressing their concentrations as fractions of toxic units. The fate of the compounds in the water, and responses of phytoplankton, zooplankton, periphyton, macroinvertebrates, macrophytes, decomposition, and water quality were followed for 13 weeks. The half-lives of lambda-cyhalothrin, metamitron, and fluazinam were 1 to 2 d; that of asulam was >30 d. No consistent effects could be demonstrated for the 0.2% treatment regime that was therefore considered the no-observed-effect concentration community (NOEC). The macroinvertebrate populations of Gammarus pulex, Asellus aquaticus, and Proasellus meridianus were the most sensitive end points, followed by species of copepods and cladocerans. Responses mainly were due to lambda-cyhalothrin. The 0.5% treatment regime resulted in short-term effects. Pronounced effects were observed at the 2% and 5% treatment levels. At the end of the experiment, the macrophyte biomass that consisted of Elodea nuttallii, showed a decline at the two highest treatment levels, asulam being the causal factor (NOEC: 0.5% treatment level). Primary production was reduced at the 5% treatment level only. In our experiment, the first-tier risk assessment procedure for individual compounds was adequate for protecting sensitive populations exposed to realistic combinations of pesticides. Spray drift reduction measures seem to be efficient in protecting aquatic ecosystems in agricultural areas.

Fungal composition on leaves explains pollutant-mediated indirect effects on amphipod feeding.

PubMed

Bundschuh, Mirco; Zubrod, Jochen P; Kosol, Sujitra; Maltby, Lorraine; Stang, Christoph; Duester, Lars; Schulz, Ralf

2011-07-01

The energy stored in coarse particulate organic matter, e.g. leaf litter, is released to aquatic ecosystems by breakdown processes involving microorganisms and leaf shredding invertebrates. The palatability of leaves and thus the feeding of shredders on leaf material are highly influenced by microorganisms. However, implications in the colonization of leaves by microorganisms (=conditioning) caused by chemical stressors are rarely studied. Our laboratory experiments, therefore, investigated for the first time effects of a fungicide on the conditioning process of leaf material by means of food-choice experiments using Gammarus fossarum (Crustacea: Amphipoda). Additionally, microbial analyses were conducted to facilitate the mechanistic understanding of the observed behavior. Gammarids significantly preferred control leaf discs over those conditioned in presence of the fungicide tebuconazole at concentrations of 50 and 500 μg/L. Besides the decrease of fungal biomass with increasing fungicide concentration, also the leaf associated fungal community composition showed that species preferred by gammarids, such as Alatospora acumunata, Clavariopsis aquatica, or Flagellospora curvula, were more frequent in the control. Tetracladium marchalianum, however, which is rejected by gammarids, was abundant in all treatments suggesting an increasing importance of this species for the lower leaf palatability--as other more palatable fungal species were almost absent--in the fungicide treatments. Hence, the food-choice behavior of G. fossarum seems to be a suitable indicator for alterations in leaf associated microbial communities, especially fungal species composition, caused by chemical stressors. Finally, this or similar test systems may be a reasonable supplement to the environmental risk assessment of chemicals in order to achieve its protection goals, as on the one hand, indirect effects may occur far below concentrations known to affect gammarids directly, and on the other

Hydrology and water resources in Caspian Sea

NASA Astrophysics Data System (ADS)

Haddadi Moghaddam, Kourosh

2016-10-01

Precipitation is the main driver of the water balance variability of the water over space and time, and changes in precipitation have very important implications for hydrology and water resources. Variations in precipitation over daily, seasonal, annual, and decadal time scales influence hydrological variability over time in a catchment. Flood frequency is affected by changes in the year-to-year variability in precipitation and by changes in short-term rainfall properties. Desiccation of the Caspian Sea is one of the world's most serious ecosystem catastrophes. The Persian Sturgeon (Acipenser persicus) caught under 10 m depth using bottom trawl net by research vessel during winter 2012, summer and winter 2013 and spring 2014 in east, central and west of southern parts of Caspian Sea, then, their diets were investigated. During 136 trawling in the aimed seasons, Persian sturgeon with 1 to 2 years old and 179.67 × 0.2 g (body weight) and 29.97 ± 0.4 cm (Total length) captured. Examination of stomach contents in the sturgeon specimens revealed that the food spectrum was composed of bony fishes (Neogobius sp., Atherina sp. and Clupeonella delicatula), invertebrates belonging to the family Ampharetidae polychaeta worms including (Hypanai sp. and Nereis diversicolor), various crustaceans (Gammarus sp. and Paramysis sp.). Investigation on stomach contents of sturgeon Acipenser persicus caught under 10 m depth in 2012 to 2013 surveys showed that there is significant difference in the consumed food. The most food diversity have been observed in winter 2013, also Polychaeta is the primary consumed food and crustacean is the secondary one (P > 0.05), no new types of food (such as bony fishes or benthics) have been observed on food chain of Acipenser persicus and shows no significant difference (P > 0.05).

Wind effects on prey availability: How northward migrating waders use brackish and hypersaline lagoons in the sivash, Ukraine

NASA Astrophysics Data System (ADS)

Verkuil, Yvonne; Koolhaas, Anita; Van Der Winden, Jan

Large numbers of waders migrating northward in spring use the Sivash, a large system of shallow, brackish and hypersaline lagoons in the Black Sea and Azov Sea region (Ukraine). The bottoms of these lagoons are often uncovered by the wind. Hence, for waders the time and space available for feeding depend on wind conditions. In hypersaline lagoons the benthic and pelagic fauna was very poor, consisting mainly of chironomid larvae (0.19 g AFDM·m -2) and brine shrimps Artemia salina, respectively. Brine shrimp abundance was correlated with salinity, wind force, wind direction and water depth. Dunlin Calidris alpina and curlew sandpiper Calidris ferruginea were the only species feeding on brine shrimp. As brine shrimp densities are higher in deeper water, smaller waders such as broad-billed sandpipers Limicola falcinellus are too short-legged to reach exploitable densities of brine shrimp. In brackish lagoons the benthic and pelagic fauna was rich, consisting of polychaetes, bivalves, gastropods, chironomid larvae, isopods and amphipods (8.9 to 30.5 g AFDM·m -2), but there were no brine shrimps. Prey biomass increased with the distance from the coast, being highest on the site that was most frequently inundated. Dunlin, broad-billed sandpiper and grey plover Pluvialis squatarola were the most abundant birds in the brackish lagoon. Due to the effects of wind-tides only a small area was usually available as a feeding site. Gammarus insensibilis was the alternative prey resource in the water layer, and their density varied with wind direction in the same way as brine shrimp. Curlew sandpipers and dunlins in the hypersaline lagoons and broad-billed sandpipers in the brackish lagoons often changed feeding sites, probably following the variation in prey availability. Only because of the large size and variety of lagoons are waders in the Sivash always able to find good feeding sites.

SIFamide peptides in clawed lobsters and freshwater crayfish (Crustacea, Decapoda, Astacidea): a combined molecular, mass spectrometric and electrophysiological investigation.

PubMed

Dickinson, Patsy S; Stemmler, Elizabeth A; Cashman, Christopher R; Brennan, Henry R; Dennison, Bobbi; Huber, Kristen E; Peguero, Braulio; Rabacal, Whitney; Goiney, Christopher C; Smith, Christine M; Towle, David W; Christie, Andrew E

2008-04-01

Recently, we identified the peptide VYRKPPFNGSIFamide (Val(1)-SIFamide) in the stomatogastric nervous system (STNS) of the American lobster Homarus americanus using matrix-assisted laser desorption/ionization-Fourier transform mass spectrometry (MALDI-FTMS). Given that H. americanus is the only species thus far shown to possess this peptide, and that a second SIFamide isoform, Gly(1)-SIFamide, is broadly conserved in other decapods, including another astacidean, the crayfish Procambarus clarkii, we became interested both in confirming our identification of Val(1)-SIFamide via molecular methods and in determining the extent to which this isoform is conserved within other members of the infraorder Astacidea. Here, we present the identification and characterization of an H. americanus prepro-SIFamide cDNA that encodes the Val(1) isoform. Moreover, we demonstrate via MALDI-FTMS the presence of Val(1)-SIFamide in a second Homarus species, Homarus gammarus. In contrast, only the Gly(1) isoform was detected in the other astacideans investigated, including the lobster Nephrops norvegicus, a member of the same family as Homarus, and the crayfish Cherax quadricarinatus, P. clarkii and Pacifastacus leniusculus, which represent members of each of the extant families of freshwater astacideans. These results suggest that Val(1)-SIFamide may be a genus (Homarus)-specific isoform. Interestingly, both Val(1)- and Gly(1)-SIFamide possess an internal dibasic site, Arg(3)-Lys(4), raising the possibility of the ubiquitously conserved isoform PPFNGSIFamide. However, this octapeptide was not detected via MALDI-FTMS in any of the investigated species, and when applied to the isolated STNS of H. americanus possessed little bioactivity relative to the full-length Val(1) isoform. Thus, it appears that the dodeca-variants Val(1)- and Gly(1)-SIFamide are the sole bioactive isoforms of this peptide family in clawed lobsters and freshwater crayfish.

Design and operation of a low-cost and compact autonomous buoy system for use in coastal aquaculture and water quality monitoring.

PubMed

Schmidt, Wiebke; Raymond, David; Parish, David; Ashton, Ian G C; Miller, Peter I; Campos, Carlos J A; Shutler, Jamie D

2018-01-01

The need to ensure future food security and issues of varying estuarine water quality is driving the expansion of aquaculture into near-shore coastal waters. It is prudent to fully evaluate new or proposed aquaculture sites, prior to any substantial financial investment in infrastructure and staffing. Measurements of water temperature, salinity and dissolved oxygen can be used to gain insight into the physical, chemical and biological water quality conditions within a farm site, towards identifying its suitability for farming, both for the stock species of interest and for assessing the potential risk from harmful or toxic algae. The latter can cause closure of shellfish harvesting. Unfortunately, commercial scientific monitoring systems can be cost prohibitive for small organisations and companies to purchase and operate. Here we describe the design, construction and deployment of a low cost (<£ 5000) monitoring buoy suitable for use within a near-shore aquaculture farm or bathing waters. The mooring includes a suite of sensors designed for supporting and understanding variations in near-shore physical, chemical and biological water quality. The system has been designed so that it can be operated and maintained by non-scientific staff, whilst still providing good quality scientific data. Data collected from two deployments totalling 14 months, one in a coastal bay location, another in an estuary, have illustrated the robust design and provided insight into the suitability of these sites for aquaculture and the potential occurrence of a toxin causing algae ( Dinophysis spp.). The instruments maintained good accuracy during the deployments when compared to independent in situ measurements (e.g. RMSE 0.13-0.16 °C, bias 0.03-0.08 °C) enabling stratification and biological features to be identified, along with confirming that the waters were suitable for mussel ( Mytilus spp.) and lobster ( Homarus gammarus ) aquaculture, whilst sites showed conditions agreeable

Effects of repeated insecticide pulses on macroinvertebrate drift in indoor stream mesocosms.

PubMed

Berghahn, Rüdiger; Mohr, Silvia; Hübner, Verena; Schmiediche, Ronny; Schmiedling, Ina; Svetich-Will, Erkki; Schmidt, Ralf

2012-10-15

Pesticide contaminations via run-off or spray drift have been reported to result in the mass drift of macroinvertebrates as well as causing structural and functional changes of the corresponding stream sections. However, pesticide pulses in the field are associated with sudden increases in flow velocity, water turbidity, and changes in water temperature, which can also induce drift. Only through replicated community testing under highly controlled conditions can these effects be disentangled. In a stream mesocosm study, 12-h pulses of 12 μg/L imidacloprid were set three times at weekly intervals and are considered a "pulse series". Two pulse series of this neonicotinoid insecticide were run in both spring and summer with 4 treatment and 4 control stream mesocosms used in each pulse series. Prior to the start of the mesocosm experiment, both pulse concentration and duration had been screened for drift responses in larval Baetidae, Chironomidae and adult Gammarus roeseli in laboratory experiments. In the subsequent mesocosm study, each pulse caused a pronounced increase in the drift of insect larvae and gammarids. The drift response was taxon-specific, which was related to preferred habitat and exposure to other stressors like current velocity, in addition to imidacloprid sensitivity. Activity measurements employing a Multispecies Freshwater Biomonitor(®) revealed that in Baetis sp. the diurnal activity pattern became more pronounced even 12h after the pulse though with slightly decreased mean physical activity. Adult G. roeseli showed a drastic pulse by pulse decrease in physical activity which after the 3rd pulse lasted longer than 24h. In conclusion, drift is a sensitive, ecologically relevant endpoint and should be regarded when a specific risk assessment for lotic surface waters is done, e.g. in the context of a spatially explicit risk assessment. Copyright © 2012 Elsevier B.V. All rights reserved.

Behavioural changes in three species of freshwater macroinvertebrates exposed to the pyrethroid lambda-cyhalothrin: laboratory and stream microcosm studies.

PubMed

Nørum, Ulrik; Friberg, Nikolai; Jensen, Maria R; Pedersen, Jakob M; Bjerregaard, Poul

2010-07-15

Pesticides are transported from crop fields to adjacent streams via surface run-off, drains, groundwater, wind drift and atmospheric deposition and give rise to transient pulse contamination. Although the concentrations observed, typically <10 microg L(-1), cannot be expected to be acutely lethal, effects in streams at the population and ecosystem level have been reported. One of the most conspicuous phenomena associated with these transient pesticide pulses is drift, where large numbers of freshwater invertebrates are carried along by the current and disappear from the contaminated stretch of the stream. The aim of the present study was to evaluate the feasibility of linking laboratory studies of the sublethal effects of pulse exposure to the pyrethroid lambda-cyhalothrin on the locomotory behaviour of stream invertebrates with effects on drift behaviour under more environmentally realistic conditions in stream microcosms. In the laboratory as well as in the microcosms, the order of sensitivities of the three species tested was (with Leuctra nigra being the most sensitive): L. nigra>Gammarus pulex>Heptagenia sulphurea. The LOECs determined for L. nigra (1 ng L(-1)), G. pulex (10 ng L(-1)) and H. sulphurea (100 ng L(-1)) are all within expected environmental concentrations. For the species of invertebrates investigated, it was possible to extrapolate directly from pyrethroid-induced behavioural changes observed in the laboratory to drift under more realistic conditions in stream microcosms. Consequently, the fast and cost-effective video tracking methodology may be applied for screening for potential effects of a wider range of pesticides and other stressors on the locomotory behaviour of freshwater invertebrates. The results indicate that such behavioural changes may be predictive of effects at the ecosystem level. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Invertebrate predation on egg masses of the European cuttlefish, Sepia officinalis: An experimental approach

NASA Astrophysics Data System (ADS)

Martins, Catarina P. P.; Fernández-Álvarez, Fernando Á.; Villanueva, Roger

2018-01-01

The eggs of the European cuttlefish, Sepia officinalis, develop attached to the seafloor in shallow water habitats and possess a relatively thick black capsule that protects them from the surrounding environment. Since embryological development may take several months, eggs are vulnerable to a variety of threats present in shallow waters, including predation. This study investigates predation of S. officinalis eggs by benthic invertebrates. Twenty-eight invertebrate species from 6 different phyla and with diverse feeding habits were tested as potential predators under laboratory conditions. We also investigated how the feeding traits of these species are related to the mechanical ability to break the egg capsule and prey upon cuttlefish embryos. Species that fed on cuttlefish eggs were the sea snail Bolinus brandaris, the crab Cancer pagurus, the hermit crab Dardanus arrosor, the lobster Homarus gammarus, the invasive blue crab Callinectes sapidus, the shrimp Squilla mantis, the sea urchins Echinus melo, Cidaris sp. and Paracentrotus lividus and the starfish Astropecten aranciacus. It is of note that C. sapidus is a potential predatory crab, which raises the concern that this invasive species may constitute a novel threat for cuttlefish eggs as more populations become established in NE Atlantic waters. Of the biological traits examined, prey capture tools in the tested species best explained the experimental feeding results, suggesting that predation of S. officinalis eggs was determined generally by a mechanical factor and highlighting the importance of the protective egg capsule against predators. However, chemosensory factors are likely to be implicated as well. Thus, this work contributes to the understanding of the ecology of early life stages of cuttlefish and the factors that can affect offspring survival and subsequently impact the recruitment of this species.

(Cryptic) sex in the microsporidian Nosema granulosis--evidence from parasite rDNA and host mitochondrial DNA.

PubMed

Krebes, Lukas; Zeidler, Lisza; Frankowski, Jens; Bastrop, Ralf

2014-01-01

Microsporidia are single-celled, intracellular eukaryotes that parasitise a wide range of animals. The Nosema/Vairimorpha group includes some putative asexual species, and asexuality is proposed to have originated multiple times from sexual ancestors. Here, we studied the variation in the ribosomal DNA (rDNA) of 14 isolates of the presumed apomictic and vertically transmitted Nosema granulosis to evaluate its sexual status. The analysed DNA fragment contained a part of the small-subunit ribosomal gene (SSU) and the entire intergenic spacer (IGS). The mitochondrial cox1 gene of the host Gammarus duebeni (Crustacea) was analysed to temporally calibrate the system and to test the expectation of cophylogeny of host and parasite genealogies. Genetic variability of the SSU gene was very low within and between the isolates. In contrast, intraisolate (within a single host) variability of the IGS felt in two categories, because 12 isolates possess a very high IGS genetic diversity and two isolates were almost invariable in the IGS. This difference suggests variable models of rDNA evolution involving birth-and-death and unexpectedly concerted evolution. An alternative explanation could be a likewise unattended mixed infection of host individuals by more than one parasite strain. Despite considerable genetic divergence between associated host mitochondrial haplotypes, some N. granulosis 'IGS populations' seem not to belong to different gene pools; the relevant tests failed to show significant differences between populations. A set of recombinant IGS sequences made our data incompatible with the model of a solely maternally inherited, asexual species. In line with recent reports, our study supports the hypothesis that some assumed apomictic Microsporidia did not entirely abstain from the evolutionary advantages of sex. In addition, the presented data indicate that horizontal transmission may occur occasionally. This transmission mode could be a survival strategy of N

Multi-residue analysis of emerging pollutants in benthic invertebrates by modified micro-quick-easy-cheap-efficient-rugged-safe extraction and nanoliquid chromatography-nanospray-tandem mass spectrometry analysis.

PubMed

Berlioz-Barbier, Alexandra; Buleté, Audrey; Faburé, Juliette; Garric, Jeanne; Cren-Olivé, Cécile; Vulliet, Emmanuelle

2014-11-07

Aquatic ecosystems are continuously contaminated by agricultural and industrial sources. Although the consequences of this pollution are gradually becoming visible, their potential impacts on aquatic ecosystems are poorly known, particularly regarding the risk of bioaccumulation in different trophic levels. To establish a causality relationship between bioaccumulation and disease, experiments on biotic matrices must be performed. In this context, a multi-residue method for the analysis of 35 emerging pollutants in three benthic invertebrates (Potamopyrgus antipodarum, Gammarus fossarum, and Chironomus riparius) has been developed. Because the variation in response of each individual must be taken into account in ecotoxicological studies, the entire analytical chain was miniaturised, thereby reducing the required sample size to a minimum of one individual and scaling the method accordingly. A new extraction strategy based on a modified, optimised and miniaturised "QuEChERS" approach is reported. The procedure involves salting out liquid-liquid extraction of approximately 10-20mg of matrix followed by nano-liquid chromatography-nano electospray ionisation coupled with tandem mass spectrometry. The validated analytical procedure exhibited recoveries between 40 and 98% for all the target compounds and enabled the determination of pollutants on an individual scale in the ng g(-1) concentration. The method was subsequently applied to determine the levels of target analytes in several encaged organisms which were exposed upstream and downstream of an effluent discharge. The results highlighted a bioaccumulation of certain targeted emerging pollutants in three freshwater invertebrates, as well as inter-species differences. 18 out of 35 compounds were detected and eight were quantified. The highest concentrations were measured for ibuprofen in G. fossarum, reaching up to 105 ng g(-1). Copyright © 2014 Elsevier B.V. All rights reserved.

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.

Studying the movement behavior of benthic macroinvertebrates with automated video tracking.

PubMed

Augusiak, Jacqueline; Van den Brink, Paul J

2015-04-01

Quantifying and understanding movement is critical for a wide range of questions in basic and applied ecology. Movement ecology is also fostered by technological advances that allow automated tracking for a wide range of animal species. However, for aquatic macroinvertebrates, such detailed methods do not yet exist. We developed a video tracking method for two different species of benthic macroinvertebrates, the crawling isopod Asellus aquaticus and the swimming fresh water amphipod Gammarus pulex. We tested the effects of different light sources and marking techniques on their movement behavior to establish the possibilities and limitations of the experimental protocol and to ensure that the basic handling of test specimens would not bias conclusions drawn from movement path analyses. To demonstrate the versatility of our method, we studied the influence of varying population densities on different movement parameters related to resting behavior, directionality, and step lengths. We found that our method allows studying species with different modes of dispersal and under different conditions. For example, we found that gammarids spend more time moving at higher population densities, while asellids rest more under similar conditions. At the same time, in response to higher densities, gammarids mostly decreased average step lengths, whereas asellids did not. Gammarids, however, were also more sensitive to general handling and marking than asellids. Our protocol for marking and video tracking can be easily adopted for other species of aquatic macroinvertebrates or testing conditions, for example, presence or absence of food sources, shelter, or predator cues. Nevertheless, limitations with regard to the marking protocol, material, and a species' physical build need to be considered and tested before a wider application, particularly for swimming species. Data obtained with this approach can deepen the understanding of population dynamics on larger spatial scales and

Studying the movement behavior of benthic macroinvertebrates with automated video tracking

PubMed Central

Augusiak, Jacqueline; Van den Brink, Paul J

2015-01-01

Quantifying and understanding movement is critical for a wide range of questions in basic and applied ecology. Movement ecology is also fostered by technological advances that allow automated tracking for a wide range of animal species. However, for aquatic macroinvertebrates, such detailed methods do not yet exist. We developed a video tracking method for two different species of benthic macroinvertebrates, the crawling isopod Asellus aquaticus and the swimming fresh water amphipod Gammarus pulex. We tested the effects of different light sources and marking techniques on their movement behavior to establish the possibilities and limitations of the experimental protocol and to ensure that the basic handling of test specimens would not bias conclusions drawn from movement path analyses. To demonstrate the versatility of our method, we studied the influence of varying population densities on different movement parameters related to resting behavior, directionality, and step lengths. We found that our method allows studying species with different modes of dispersal and under different conditions. For example, we found that gammarids spend more time moving at higher population densities, while asellids rest more under similar conditions. At the same time, in response to higher densities, gammarids mostly decreased average step lengths, whereas asellids did not. Gammarids, however, were also more sensitive to general handling and marking than asellids. Our protocol for marking and video tracking can be easily adopted for other species of aquatic macroinvertebrates or testing conditions, for example, presence or absence of food sources, shelter, or predator cues. Nevertheless, limitations with regard to the marking protocol, material, and a species’ physical build need to be considered and tested before a wider application, particularly for swimming species. Data obtained with this approach can deepen the understanding of population dynamics on larger spatial scales

Responses of aquatic organisms to metal pollution in a lowland river in Flanders: a comparison of diatoms and macroinvertebrates.

PubMed

De Jonge, Maarten; Van de Vijver, Bart; Blust, Ronny; Bervoets, Lieven

2008-12-15

The role of macroinvertebrates and diatoms as indicator for metal pollution was investigated by assessing both biota along a metal gradient in the Belgian river the Dommel. Macroinvertebrates and diatoms were sampled in summer and winter and physical-chemical characteristics of the water were measured at four different sample periods and related to sediment characteristics. Although metal concentrations, except cadmium, in the water nowhere exceeded water quality standards, high metal concentrations were measured in the sediment, indicating historical contamination of the Dommel. At the sites that were situated downstream of the pollution source, high levels of conductivity and chloride were measured in the water. Redundancy Analysis (RDA) indicated pH, phosphate and zinc as the significant environmental variables explaining each respectively 7.7%, 11.6% and 22.6% of the macroinvertebrate community composition. Two clusters could be separated, with Gammarus pulex, Leptocerus interruptus, Baetis rhodani and Cloeon dipterum associated with low zinc concentrations and Tubificidae, Asellus aquaticus, Erpobdella sp. and Chironomus thummi-plumosus associated with higher zinc concentrations. Ammonium (10.6%), conductivity (16.5%), chloride (11.4%) and zinc (5.9%) turned out to be significant variables explaining the diatom community structure. Based on physical-chemical differences and species composition, three different groups could be separated. With this Tabellaria flocculosa and Fragilaria capucina var. rumpens were associated with low metal concentrations, Gomphonema parvulum and Nitzschia palea with elevated concentrations and Eolimna minima and Sellaphora seminulum with high zinc concentrations. In conclusion, the diatom community best reflected the metal gradient. With regard to water quality indices, those based on macroinvertebrates best followed the metal pollution gradient and were most strongly correlated with physical-chemical variables of water and

Influence of salinity regime on the food-web structure and feeding ecology of fish species from Mediterranean coastal lagoons

NASA Astrophysics Data System (ADS)

Prado, Patricia; Vergara, Carolina; Caiola, Nuno; Ibáñez, Carles

2014-02-01

Dual δ15N and δ13C analyses and estimates of biomass were used to characterize the food webs of valuable fish species in three coastal lagoons of the Ebro Delta subjected to contrasting salinity regimes (polyhaline in the Tancada lagoon, mesohaline in the Encanyissada and oligohaline in the Clot lagoon). The δ13C signatures of the entire food-web including primary producers, sediment organic matter and consumers showed the most enriched values in the Tancada lagoon (from approx. -4.8‰ in sediments to -19.7‰ in fish) and the most depleted ones in the Clot lagoon (from approx. -11.4‰ in sediments to -25.4‰ in fish), consistent with dominant contributions from marine and continental sources, respectively. For δ15N, particularly high values were detected in the submersed vegetation (11.3 ± 0.3‰) together with more enriched sediment values at lower salinities (by approx. 2.5‰), suggesting that historical loadings of agricultural fertilizers are still retained by the systems and transmitted across trophic levels. Negative relationships between δ15N and salinity were also observed for the amphipod Gammarus aequicauda and the isopod Sphaeroma hookeri, suggesting some consumption of accumulated and resuspended detrital material. In contrast, δ15N signatures of fish showed lower values and inconsistent patterns, possibly because most species have a seasonal use of the lagoons. The biomass of fish species did not show a clear effect of the salinity regime (except for the mosquitofish Gambusia holbrookii), but results for mixing models suggest a diet shift from higher contribution of zooplankton size fractions in the Encanyissada (from 57 to 73%) to macrofauna at the other lagoons (from 40 to 67%). We suggest that alterations in salinity might modify the trophic dynamics of the systems from benthic to planktonic pathways, without large-scale differences in δ15N of fish suggestive of similar trophic levels.

Pesticide impacts on predator-prey interactions across two levels of organisation.

PubMed

Rasmussen, Jes Jessen; Nørum, Ulrik; Jerris, Morten Rygaard; Wiberg-Larsen, Peter; Kristensen, Esben Astrup; Friberg, Nikolai

2013-09-15

In this study, we aimed to evaluate the effects of a short pulse exposure of the pyrethroid lambda-cyhalothrin (LC) on the predator and anti-predator behaviour of the same species; Gammarus pulex. Predator behaviour, at the level of the individual, was studied in indoor microcosms using video tracking equipment during simultaneous exposure of the predator (G. pulex) and its prey (Leuctra nigra) during 90 min exposure of 1, 6.6 or 62.1 ngL(-1) LC. During an initial 30 min of exposure, the predator and prey organisms were maintained physically separated, and the actual interaction was studied through the subsequent 60 min of exposure. The anti-predator behaviour of G. pulex (drift suppression in response to the presence of brown trout) was studied in outdoor stream channels during a 90 min pulse exposure to LC (7.4 or 79.5 ngL(-1)) with, or without, brown trout. Based on survival curves for L. nigra we found that the mortality rate for L. nigra significantly decreased during exposure to 6.6 and 62.1 ngL(-1) LC (P<0.05 and P<0.001, respectively). We found no significant effects suggesting that G. pulex was repelled by contaminated prey items (P>0.05). We found that the exposure of G. pulex to 7.4 and 79.5 ngL(-1) LC significantly increased drift (from ∼0% to ∼100% in both treatments; P<0.001) independent of the presence of brown trout (P<0.05). In other words, the natural anti-predator behaviour of G. pulex was overruled by the stress response to LC exposure increasing G. pulex predation risk from drift feeding brown trouts. Our results show that the anti-predator and predator behaviour of G. pulex were significantly changed during exposure to very low and environmentally realistic LC concentrations and exposure duration. The potential implications for the field scenario are discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

Ecosystem ecology meets adaptive management: food web response to a controlled flood on the Colorado River, Glen Canyon

USGS Publications Warehouse

Cross, Wyatt F.; Baxter, Colden V.; Donner, Kevin C.; Rosi-Marshall, Emma J.; Kennedy, Theodore A.; Hall, Robert O.; Wellard Kelly, Holly A.; Rogers, R. Scott

2011-01-01

Large dams have been constructed on rivers to meet human demands for water, electricity, navigation, and recreation. As a consequence, flow and temperature regimes have been altered, strongly affecting river food webs and ecosystem processes. Experimental high-flow dam releases, i.e., controlled floods, have been implemented on the Colorado River, USA, in an effort to reestablish pulsed flood events, redistribute sediments, improve conditions for native fishes, and increase understanding of how dam operations affect physical and biological processes. We quantified secondary production and organic matter flows in the food web below Glen Canyon dam for two years prior and one year after an experimental controlled flood in March 2008. Invertebrate biomass and secondary production declined significantly following the flood (total biomass, 55% decline; total production, 56% decline), with most of the decline driven by reductions in two nonnative invertebrate taxa, Potamopyrgus antipodarum and Gammarus lacustris. Diatoms dominated the trophic basis of invertebrate production before and after the controlled flood, and the largest organic matter flows were from diatoms to the three most productive invertebrate taxa (P. antipodarum, G. lacustris, and Tubificida). In contrast to invertebrates, production of rainbow trout (Oncorhynchus mykiss) increased substantially (194%) following the flood, despite the large decline in total secondary production of the invertebrate assemblage. This counterintuitive result is reconciled by a post-flood increase in production and drift concentrations of select invertebrate prey (i.e., Chironomidae and Simuliidae) that supported a large proportion of trout production but had relatively low secondary production. In addition, interaction strengths, measured as species impact values, were strongest between rainbow trout and these two taxa before and after the flood, demonstrating that the dominant consumer—resource interactions were not

Impaired ecosystem process despite little effects on populations: modeling combined effects of warming and toxicants.

PubMed

Galic, Nika; Grimm, Volker; Forbes, Valery E

2017-08-01

Freshwater ecosystems are exposed to many stressors, including toxic chemicals and global warming, which can impair, separately or in combination, important processes in organisms and hence higher levels of organization. Investigating combined effects of warming and toxicants has been a topic of little research, but neglecting their combined effects may seriously misguide management efforts. To explore how toxic chemicals and warming, alone and in combination, propagate across levels of biological organization, including a key ecosystem process, we developed an individual-based model (IBM) of a freshwater amphipod detritivore, Gammarus pseudolimnaeus, feeding on leaf litter. In this IBM, life history emerges from the individuals' energy budgets. We quantified, in different warming scenarios (+1-+4 °C), the effects of hypothetical toxicants on suborganismal processes, including feeding, somatic and maturity maintenance, growth, and reproduction. Warming reduced mean adult body sizes and population abundance and biomass, but only in the warmest scenarios. Leaf litter processing, a key contributor to ecosystem functioning and service delivery in streams, was consistently enhanced by warming, through strengthened interaction between the detritivorous consumer and its resource. Toxicant effects on feeding and maintenance resulted in initially small adverse effects on consumers, but ultimately led to population extinction and loss of ecosystem process. Warming in combination with toxicants had little effect at the individual and population levels, but ecosystem process was impaired in the warmer scenarios. Our results suggest that exposure to the same amount of toxicants can disproportionately compromise ecosystem processing depending on global warming scenarios; for example, reducing organismal feeding rates by 50% will reduce resource processing by 50% in current temperature conditions, but by up to 200% with warming of 4 °C. Our study has implications for

Assessing Fish and Motile Fauna around Offshore Windfarms Using Stereo Baited Video

PubMed Central

Griffin, Ross A.; Robinson, Gary J.; West, Ashley; Gloyne-Phillips, Ian T.; Unsworth, Richard K. F.

2016-01-01

There remains limited knowledge of how offshore windfarm developments influence fish assemblages, particularly at a local scale around the turbine structures. Considering the existing levels of anthropogenic pressures on coastal fish populations it is becoming increasingly important for developers and environmental regulators to gain a more comprehensive understanding of the factors influencing fish assemblages. Improving our ability to assess such fish populations in close proximity to structures will assist in increasing this knowledge. In the present study we provide the first trial use of Baited Remote Underwater Stereo-Video systems (stereo BRUVs) for the quantification of motile fauna in close proximity to offshore wind turbines. The study was conducted in the Irish Sea and finds the technique to be a viable means of assessing the motile fauna of such environments. The present study found a mixture of species including bottom dwellers, motile crustaceans and large predatory fish. The majority of taxa observed were found to be immature individuals with few adult individuals recorded. The most abundant species were the angular crab (Goneplax rhomboides) and the small-spotted catshark (Scyliorhinus canicula). Of note in this study was the generally low abundance and diversity of taxa recorded across all samples, we hypothesise that this reflects the generally poor state of the local fauna of the Irish Sea. The faunal assemblages sampled in close proximity to turbines were observed to alter with increasing distance from the structure, species more characteristic of hard bottom environments were in abundance at the turbines (e.g. Homarus gammarus, Cancer pagarus, Scyliorhinus spp.) and those further away more characteristic of soft bottoms (e.g. Norwegian Lobster). This study highlights the need for the environmental impacts of offshore renewables on motile fauna to be assessed using targeted and appropriate tools. Stereo BRUVs provide one of those tools, but like

A long-term copper exposure in a freshwater ecosystem using lotic mesocosms: Invertebrate community responses

USGS Publications Warehouse

Joachim, Sandrine; Roussel, Hélène; Bonzom, Jean-Marc; Thybaud, Eric; Mebane, Christopher A.; Brink, Paul Van den; Gauthier, Laury

2017-01-01

A lotic mesocosm study was carried out in 20-m-long channels, under continuous, environmentally realistic concentrations of copper (Cu) in low, medium, and high exposures (nominally 0, 5, 25, and 75 μg L−1; average effective concentrations <0.5, 4, 20, and 57 μg L−1 respectively) for 18 mo. Total abundance, taxa richness, and community structure of zooplankton, macroinvertebrates, and emerging insects were severely affected at Cu treatment levels of 25 and 75 μg L−1. Some taxa were sensitive to Cu, including gastropods such as Lymnaea spp. and Physasp., crustaceans such as Chydorus sphaericus, Gammarus pulex, and Asellus aquaticus, rotifers such as Mytilina sp. and Trichocerca sp., leeches such as Erpobdella sp., and the emergence of dipteran insects such as Chironomini. Other taxa appeared to be tolerant or favored by indirect effects, as in Chironimidae larvae, the emergence of Orthocladiinae, and the zooplankter Vorticella sp., which increased in the 25 and 75 μg L−1 treatments. After approximately 8 mo of Cu exposure, the macroinvertebrate community in the high treatment was decimated to the point that few organisms could be detected, with moderate effects in the medium treatment, and very slight effects in the low-Cu treatment. Subsequently, most taxa in the high-Cu exposure began a gradual and partial recovery. By the end of the study at 18 mo, macroinvertebrate taxa richness was similar to control richness, although overall abundances remained lower than controls. After 18 mo of copper exposure, a no-observed-effect concentration at the community level for consumers was set at 5 μg L−1 (4 μg L−1 as average effective concentration), and a lowest-observed-effect concentration at 25 μg L−1(20 μg L−1 as average effective concentration). 

Allelopathic potential and ecotoxicity evaluation of gallic and nonanoic acids to prevent cyanobacterial growth in lentic systems: A preliminary mesocosm study.

PubMed

Techer, Didier; Fontaine, Pascal; Personne, Aline; Viot, Sandrine; Thomas, Marielle

2016-03-15

The increase in anthropogenic nutrient loading affecting many freshwater ecosystems combined with global warming may lead to cyanobacterial blooms on an increasingly frequent basis. Among the various physicochemical and biological methods which have been proposed to rapidly control blue-green algae growth, the use of plant-derived substances such as allelochemicals has gained great interest as an environment-friendly approach. The primary aim of this work was to evaluate the efficiency of gallic and nonanoic acid application to preemptively inhibit cyanobacterial growth in lentic hydrosystems. In order to address the process feasibility under realistic exposure scenarios, thirteen outdoor freshwater mesocosms (unit volume: 3m(3)) were designed, each containing phytoplankton (including local blue-green algae species) and various non-target organisms from higher trophic levels (Physa, Lymnaea, Gammarus, and Scardinius erythrophthalmus). After an 8-week mesocosm stabilization period, a full factorial design based on the presence/absence of gallic acid (GA) and nonanoic acid (NA) (including a control group) was implemented into the exposure tanks. Regular monitoring of major phytoplankton taxa was conducted during a 28-day experiment using an on-line fluorometer. The main results suggested that gallic acid was more efficient than nonanoic acid at limiting cyanobacterial growth at concentrations as low as 1 mg L(-1). Successive gallic acid applications (at 1, 2 and 4 mg L(-1)) at the early stages of cyanobacterial growth did not allow the complete elimination of blue-green algae from the mesocosms. However, the specificity of the allelopathic effect of gallic acid towards cyanobacteria was compatible with the maintenance of a primary productivity in the treated tanks as indicated by the photoautotrophic growth of other algal taxa. Finally, no biomarker induction signal could be reported in non-target species. Further gallic acid application trials in lentic systems such

Crustacean amphipods from marsh ponds: a nutritious feed resource with potential for application in Integrated Multi-Trophic Aquaculture.

PubMed

Jiménez-Prada, Pablo; Hachero-Cruzado, Ismael; Giráldez, Inmaculada; Fernández-Diaz, Catalina; Vilas, César; Cañavate, José Pedro; Guerra-García, José Manuel

2018-01-01

Coastal protection, nutrient cycling, erosion control, water purification, and carbon sequestration are ecosystem services provided by salt marshes. Additionally, salt ponds offer coastal breeding and a nursery habitat for fishes and they provide abundant invertebrates, such as amphipods, which are potentially useful as a resource in aquaculture. Fishmeal and fish oil are necessary food resources to support aquaculture of carnivorous species due to their omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA). Currently, aquaculture depends on limited fisheries and feed with elevated n-3 LC-PUFA levels, but the development of more sustainable food sources is necessary. Amphipods appear to be a potential high quality alternative feed resource for aquaculture. Hence, a nutritional study was carried out for several main amphipod species- Microdeutopus gryllotalpa , Monocorophium acherusicum , Gammarus insensibilis , Melita palmata and Cymadusa filosa -in terrestrial ponds in the South of Spain. These species showed high protein content (up to 40%), high n-3 PUFA and phospholipid levels, and high levels of phophatidylcholine (PC), phosphatidylethanolamine (PE) and triacylglycerols (TAG), the latter being significantly high for M. acherusicum . M. gryllotalpa and M. acherusicum showed the highest proportion of lipids (19.15% and 18.35%, respectively). Isoleucine, glycine and alanine were the dominant amino acids in all species. In addition, amphipods collected from ponds showed low levels of heavy metals. Furthermore, the biochemical profiles of the five species of amphipods have been compared with other studied alternative prey. Therefore, pond amphipods are good candidates to be used as feed, and are proposed as a new sustainable economic resource to be used in aquaculture. G. insensibilis may be the best for intensive culture as an alternative feed resource because it shows: (1) adequate n-3 PUFA and PL composition; (2) high levels of glycine, alanine, tyrosine

Do predator-prey relationships on the river bed affect fine sediment ingress?

NASA Astrophysics Data System (ADS)

Mathers, Kate; Rice, Stephen; Wood, Paul

2016-04-01

Ecosystem engineers are organisms that alter their physical environment and thereby influence the flow of resources through ecosystems. In rivers, several ecosystem engineers are also important geomorphological agents that modify fluvial sediment dynamics. By altering channel morphology and bed material characteristics, such modifications can affect the availability of habitats for other organisms, with implications for ecosystem health and wider community composition. In this way geomorphological and ecological systems are intimately interconnected. This paper focuses on one element of this intricate abiotic-biotic coupling: the interaction between fine sediment ingress into the river bed and the predator-prey relationships of aquatic organisms living on and in the river bed. Signal crayfish (Pacifastacus leniusculus) have been shown to modify fine sediment fluxes in rivers, but their effect on fine sediment ingress into riverbeds remains unclear. Many macroinvertebrate taxa have adapted avoidance strategies to avoid predation by crayfish, with one example being the freshwater shrimp (Gammarus pulex) which relies on open interstitial spaces within subsurface sediments as a refuge from crayfish predation. Fine sedimentation that fills gravelly frameworks may preclude access to those spaces, therefore leaving freshwater shrimp susceptible to predation. Ex-situ experiments were conducted which sought to examine: i) if freshwater shrimps and signal crayfish, alone and in combination, influenced fine sediment infiltration rates; and ii) whether modifications to substratum composition, specifically the introduction of fine sediment, modified predator-prey interactions. The results demonstrate that crayfish are significant geomorphic agents and that fine sediment ingress rates were significantly enhanced in their presence compared to control conditions or the presence of only freshwater shrimps. The combination of both organisms (i.e. allowing the interaction between

Chronic toxicity of copper to five benthic invertebrates in laboratory-formulated sediment: sensitivity comparison and preliminary risk assessment.

PubMed

Roman, Yblin E; De Schamphelaere, Karel A C; Nguyen, Lien T H; Janssen, Colin R

2007-11-15

Five benthic organisms commonly used for sediment toxicity testing were chronically (28 to 35 days) exposed to copper in standard laboratory-formulated sediment (following Organization for Economic Cooperation and Development guidelines) and lethal and sub-lethal toxicities were evaluated. Sub-lethal endpoints considered were reproduction and biomass production for Lumbriculus variegatus, growth and reproduction for Tubifex tubifex, growth and emergence for Chironomus riparius, and growth for Gammarus pulex and Hyalella azteca. Expressed on whole-sediment basis the observed lethal sensitivity ranking (from most to least sensitive) was: G. pulex>L. variegatus>H. azteca=C. riparius=T. tubifex, with median chronic lethal concentrations (LC50) between 151 and 327 mg/kg dry wt. The sub-lethal sensitivity ranking (from most to least sensitive, with the most sensitive endpoint between parentheses): C. riparius (emergence)>T. tubifex (reproduction)=L. variegatus (reproduction)>G. pulex (growth)>H. azteca (growth), with median effective concentrations (EC50) between 59.2 and 194 mg/kg dry wt. No observed effect concentrations (NOEC) or 10% effective concentrations (EC10) for the five benthic invertebrates were used to perform a preliminary risk assessment for copper in freshwater sediment by means of (a) the "assessment factor approach" or (b) the statistical extrapolation approach (species sensitivity distribution). Depending on the data (NOEC or EC10) and the methodology used, we calculated a Predicted No Effect Concentration (PNEC) for sediment between 3.3 and 47.1 mg Cu/dry wt. This range is similar to the range of natural (geochemical) background concentrations of copper in sediments in Europe, i.e. 90% of sediments have a concentration between 5 and 49 mg Cu/kg dry wt. A detailed analysis of the outcome of this preliminary exercise highlighted that multiple issues need to be explored for achieving a scientifically more sound risk assessment and for the development of

Crustacean amphipods from marsh ponds: a nutritious feed resource with potential for application in Integrated Multi-Trophic Aquaculture

PubMed Central

Hachero-Cruzado, Ismael; Giráldez, Inmaculada; Fernández-Diaz, Catalina; Vilas, César; Cañavate, José Pedro; Guerra-García, José Manuel

2018-01-01

Coastal protection, nutrient cycling, erosion control, water purification, and carbon sequestration are ecosystem services provided by salt marshes. Additionally, salt ponds offer coastal breeding and a nursery habitat for fishes and they provide abundant invertebrates, such as amphipods, which are potentially useful as a resource in aquaculture. Fishmeal and fish oil are necessary food resources to support aquaculture of carnivorous species due to their omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA). Currently, aquaculture depends on limited fisheries and feed with elevated n-3 LC-PUFA levels, but the development of more sustainable food sources is necessary. Amphipods appear to be a potential high quality alternative feed resource for aquaculture. Hence, a nutritional study was carried out for several main amphipod species—Microdeutopus gryllotalpa, Monocorophium acherusicum, Gammarus insensibilis, Melita palmata and Cymadusa filosa—in terrestrial ponds in the South of Spain. These species showed high protein content (up to 40%), high n-3 PUFA and phospholipid levels, and high levels of phophatidylcholine (PC), phosphatidylethanolamine (PE) and triacylglycerols (TAG), the latter being significantly high for M. acherusicum. M. gryllotalpa and M. acherusicum showed the highest proportion of lipids (19.15% and 18.35%, respectively). Isoleucine, glycine and alanine were the dominant amino acids in all species. In addition, amphipods collected from ponds showed low levels of heavy metals. Furthermore, the biochemical profiles of the five species of amphipods have been compared with other studied alternative prey. Therefore, pond amphipods are good candidates to be used as feed, and are proposed as a new sustainable economic resource to be used in aquaculture. G. insensibilis may be the best for intensive culture as an alternative feed resource because it shows: (1) adequate n-3 PUFA and PL composition; (2) high levels of glycine, alanine, tyrosine

Phosphorus availability modulates the toxic effect of silver on aquatic fungi and leaf litter decomposition.

PubMed

Funck, J Arce; Clivot, H; Felten, V; Rousselle, P; Guérold, F; Danger, M

2013-11-15

The functioning of forested headwater streams is intimately linked to the decomposition of leaf litter by decomposers, mainly aquatic hyphomycetes, which enables the transfer of allochthonous carbon to higher trophic levels. Evaluation of this process is being increasingly used as an indicator of ecosystem health and ecological integrity. Yet, even though the individual impacts of contaminants and nutrient availability on decomposition have been well studied, the understanding of their combined effects remains limited. In the current study, we investigated whether the toxic effects of a reemerging contaminant, silver (Ag), on leaf litter decomposition could be partly overcome in situations where microorganisms were benefitting from high phosphorus (P) availability, the latter being a key chemical element that often limits detritus decomposition. We also investigated whether these interactive effects were mediated by changes in the structure of the aquatic hyphomycete community. To verify these hypotheses, leaf litter decomposition by a consortium of ten aquatic hyphomycete species was followed in a microcosm experiment combining five Ag contamination levels and three P concentrations. Indirect effects of Ag and P on the consumption of leaf litter by the detritivorous crustacean, Gammarus fossarum, were also evaluated. Ag significantly reduced decomposition but only at the highest concentration tested, independently of P level. By contrast, P and Ag interactively affected fungal biomass. Both P level and Ag concentrations shaped microbial communities without significantly affecting the overall species richness. Finally, the levels of P and Ag interacted significantly on G. fossarum feeding rates, high [Ag] reducing litter consumption and low P availability tending to intensify the feeding rate. Given the high level of contaminant needed to impair the decomposition process, it is unlikely that a direct effect of Ag on leaf litter decomposition could be observed in

Neogene paleogeography provides context for understanding the origin and spatial distribution of cryptic diversity in a widespread Balkan freshwater amphipod

PubMed Central

Mamos, Tomasz; Bącela-Spychalska, Karolina; Rewicz, Tomasz; Wattier, Remi A.

2017-01-01

Background The Balkans are a major worldwide biodiversity and endemism hotspot. Among the freshwater biota, amphipods are known for their high cryptic diversity. However, little is known about the temporal and paleogeographic aspects of their evolutionary history. We used paleogeography as a framework for understanding the onset of diversification in Gammarus roeselii: (1) we hypothesised that, given the high number of isolated waterbodies in the Balkans, the species is characterised by high level of cryptic diversity, even on a local scale; (2) the long geological history of the region might promote pre-Pleistocene divergence between lineages; (3) given that G. roeselii thrives both in lakes and rivers, its evolutionary history could be linked to the Balkan Neogene paleolake system; (4) we inspected whether the Pleistocene decline of hydrological networks could have any impact on the diversification of G. roeselii. Material and Methods DNA was extracted from 177 individuals collected from 26 sites all over Balkans. All individuals were amplified for ca. 650 bp long fragment of the mtDNA cytochrome oxidase subunit I (COI). After defining molecular operational taxonomic units (MOTU) based on COI, 50 individuals were amplified for ca. 900 bp long fragment of the nuclear 28S rDNA. Molecular diversity, divergence, differentiation and historical demography based on COI sequences were estimated for each MOTU. The relative frequency, geographic distribution and molecular divergence between COI haplotypes were presented as a median-joining network. COI was used also to reconstruct time-calibrated phylogeny with Bayesian inference. Probabilities of ancestors’ occurrence in riverine or lacustrine habitats, as well their possible geographic locations, were estimated with the Bayesian method. A Neighbour Joining tree was constructed to illustrate the phylogenetic relationships between 28S rDNA haplotypes. Results We revealed that G. roeselii includes at least 13 cryptic

Seasonal Variation, Export Dynamics and Consumption of Freshwater Invertebrates in an Estuarine Environment

NASA Astrophysics Data System (ADS)

Williams, D. D.; Williams, N. E.

1998-03-01

In the Aber Estuary, North Wales, significant numbers of freshwater benthic invertebrates occurred in the tidal freshwater area. Distinct seasonal patterns were observed in their longitudinal zonation which appeared to be unrelated to variations in tidal inundation. The December extension downstream of freshwater taxa is hypothesized to be in response to decreasing water temperatures. In April, larvae/nymphs of the Trichoptera (caddisflies), Ephemeroptera (mayflies) and Plecoptera (stoneflies) ranged as far as a site inundated by 80·9% of all high tides, and larval Elmidae and Chironomidae (midges) occurred at the most marine site (inundated twice daily by all high tides). In July, with the exception of the Chironomidae, the range of most aquatic insects had contracted to the upper estuary. Although, in general, densities of aquatic insects decreased towards the lower estuary, significant densities persisted there. For example, maxima of 3514 chironomid larvae and 48 caddisfly larvae m -2were recorded at the 80·9% inundation site. An estimated 31×10 6freshwater invertebrates (weighing 62·6 kg), per annum, passed from fresh water into salt water across any given transect along the estuary. In comparison, the annual influx of invertebrates carried upstream by incoming tides was estimated to be 1·9×10 6(6·2%; weighing 2·5 kg). Predominant in the downstream drift were the larvae/nymphs and/or pupae of chironomids, mayflies, stoneflies and caddisflies. The ' reverse ' drift comprised mainly copepods, ostracods, amphipods and oligochaetes. Mites and the brackishwater amphipod Gammarus zaddachicommonly moved in both directions. Highest drift densities occurred in July, whereas the lowest densities occurred in late autumn and winter. Multiple regression analysis showed no relationship between total drift or ' reverse ' drift densities and any of the measured environmental variables. Many of the freshwater invertebrates appeared not to die upon passing into tidal

Spatial variations in δ13C and δ15N values of primary consumers in a coastal lagoon

NASA Astrophysics Data System (ADS)

Como, S.; Magni, P.; Van Der Velde, G.; Blok, F. S.; Van De Steeg, M. F. M.

2012-12-01

The analysis of the contribution of a food source to a consumer's diet or the trophic position of a consumer is highly sensitive to the variability of the isotopic values used as input data. However, little is known in coastal lagoons about the spatial variations in the isotopic values of primary consumers considered 'end members' in the isotope mixing models for quantifying the diet of secondary consumers or as a baseline for estimating the trophic position of consumers higher up in the food web. We studied the spatial variations in the δ13C and δ15N values of primary consumers and sedimentary organic matter (SOM) within a selected area of the Cabras lagoon (Sardinia, Italy). Our aim was to assess how much of the spatial variation in isotopic values of primary consumers was due to the spatial variability between sites and how much was due to differences in short distances from the shore. Samples were collected at four stations (50-100 m apart) selected randomly at two sites (1.5-2 km apart) chosen randomly at two distances from the shore (i.e. in proximity of the shore -Nearshore - and about 200 m away from the shore -Offshore). The sampling was repeated in March, May and August 2006 using new sites at the two chosen distances from the shore on each date. The isotopic values of size-fractionated seston and macrophytes were also analyzed as a complementary characterization of the study area. While δ15N did not show any spatial variations, the δ13C values of deposit feeders, Alitta (=Neanthes) succinea, Lekanesphaera hookeri, Hydrobia acuta and Gammarus aequicauda, were more depleted Offshore than Nearshore. For these species, there were significant effects of distance or distance × dates in the mean δ13C values, irrespective of the intrinsic variation between sites. SOM showed similar spatial variations in δ13C values, with Nearshore-Offshore differences up to 6‰. This indicates that the spatial isotopic changes are transferred from the food sources to the

Limestone-based technosols: a suitable way for the remediation of sediments contaminated by heavy metals.

NASA Astrophysics Data System (ADS)

Martínez-Sanchez, Maria Jose; Garcia-Lorenzo, Mari Luz; Martínez, Salvadora; Gonzalez, Eva; Molina, Jose; Hernández, Carmen; Pérez-Sirvent, Carmen

2013-04-01

fischeri), embryogenesis assay in sea urchin (Paracentrotus lividus) and survival in estuarine amphipods (Gammarus aequicauda). The obtained results suggest that selected remediation technique reduces significantly the toxicological effect of the percolate to the tested organisms. The ecotoxicological testing may be a useful approach for assessing the toxicity as a complement to chemical analysis. In addition, the use of a battery of bioassays allows diminishing problems related to false positive results. The use of limestone filler constitutes an excellent option in sediments polluted by trace elements, because of risk for human health or ecosystems does not exist after the intervention. in addition, the designed experience allow to optimize stabilizer quantities, and may suppose a big cost-saving project in areas affected by mining activities.

A comparative biodiversity study of the associated fauna of perennial fucoids and filamentous algae

NASA Astrophysics Data System (ADS)

Råberg, Sonja; Kautsky, Lena

2007-06-01

. ANOSIM analyses of faunal composition demonstrated a significant difference between the 2 vegetation types in both areas, largely due to greater abundance of Gammarus spp. and Theodoxus fluviatilis in the fucoid vegetation. Differences observed between the F. radicans and filamentous algal vegetation types were generally more pronounced than those between F. vesiculosus and nearby filamentous algal vegetation. These observations may be due to abiotic factors that differ between the 2 investigated areas, factors such as depth distribution, wave action and eutrophication level. This study has demonstrated that the less-investigated F. radicans may be as important as the larger F. vesiculosus for the associated faunal assemblages. At the same time, the limited extent of F. radicans at shallower depths makes F. radicans vegetation potentially more vulnerable to anthropogenic changes, as declines in fucoid vegetation are usually first manifested in populations at their lower depth limits, whereas shallow populations are less affected.

Biological data on PCBs in animals other than man

USGS Publications Warehouse

Stickel, L.F.

1972-01-01

SUMMARY: Polychlorinated biphenyls have become ubiquitous in the world ecosystem in quantities similar to those of DDE. Experimental studies have shown that PCBs have a toxicity to mallards, pheasants, bobwhite quail, coturnix quail, red-winged blackbirds, starlings, cowbirds, and grackles that is of the same order as the toxicity of DDE to these species. Overt signs of poisoning also are similar to those caused by compounds of the DDT group. Toxic effects of DDE and Aroclor 1254 to coturnix chicks were additive, but not synergistic. PCBs containing higher percentages of chlorine are more toxic to birds than those containing lower percentages. PCBs of foreign manufacture contained contaminants to an extent that greatly increased their toxicity. Residues of PCBs in the brains of birds killed by these compounds measure in the hundreds of parts per million. PCBs may have contributed to mortality of some birds in the field. Toxicity to insects of PCBs of different degrees of chlorination is the reverse of the pattern in birds: the lower chlorinations are more toxic to insects. PCBs enhanced the toxicity of dieldrin and DDT to insects. Shrimp are very sensitive to PCBs and most will die as a result of 20-day exposure to a concentration of 5 ppb. PCBs also inhibit shell growth of oysters. Crabs are less sensitive; all accumulate residues to many times the concentrations in the water, and a test with crabs showed that they lost the residues very slowly. Growth of certain species of marine diatoms was experimentally inhibited by PCBs, but algae were not affected. The small marine crustacean, Gammarus, is sensitive to PCBs in concentrations of thousandths to tenths of a part per billion. Exposure to 5 ppb of Aroclor 1254 caused mortality of two species of fish in 14-45 days. Onset of death was delayed and was accompanied by fungus-like lesions. Rainbow trout were quickly killed by terphenyls at 10 ppb under normal oxygen conditions and at 2 ppb with reduced oxygen

Characterization of the hydrology, water chemistry, and aquatic communities of selected springs in the St. Johns River Water Management District, Florida, 2004

USGS Publications Warehouse

Phelps, G.G.; Walsh, Stephen J.; Gerwig, Robert M.; Tate, William B.

2006-01-01

from the Silver Springs group and in both boils at Gemini Springs. No pesticides were detected in water samples from De Leon Spring and Green Spring. Evidence of denitrification was indicated by the presence of excess nitrogen gas in water samples from most of the springs. Aquatic communities varied among the springs. Large floating mats of cyanobacteria (blue-green algae), identified as Lyngbya wollei, were observed in De Leon Spring during all sampling events in 2004. At Gemini Springs, the dominant periphyton was Rhizoclonium sp. Of the three springs sampled for benthic invertebrates, De Leon Spring had the highest overall species richness and most disturbance intolerant species (Florida Index = 4). Green Spring had the lowest species richness of the springs sampled. Based on qualitative comparisons, overall macroinvertebrate species richness seemed to be negatively related to magnesium, potassium, sodium, and specific conductance. Invertebrate abundance was greatest when dissolved oxygen and nitrate were high but phosphorus and potassium concentrations were low. Dipteran abundance seemed to be positively associated with specific conductance and total organic carbon but negatively associated with nitrate-N. Amphipods were the numerically dominant group collected in most (six of nine) collections. Shifts in amphipod abundance of the two species collected (Gammarus sp. and Hyalella azteca) varied by season among the three springs, but there were no trends evident in the variation. Fish populations were relatively species-rich at the Silver Springs group, De Leon Spring, and Gemini Springs, but not at Green Spring. Nonindigenous fish species were observed at all springs except Green Spring.

Cadmium risks to freshwater life: derivation and validation of low-effect criteria values using laboratory and field studies

USGS Publications Warehouse

Mebane, Christopher A.

2006-01-01

In 2001, the U.S. Environmental Protection Agency (EPA) released updated aquatic life criteria for cadmium. Since then, additional data on the effects of cadmium to aquatic life have become available from studies supported by the EPA, Idaho Department of Environmental Quality (IDEQ), and the U.S. Geological Survey, among other sources. Updated data on the effects of cadmium to aquatic life were compiled and reviewed and low-effect concentrations were estimated. Low-effect values were calculated using EPA's guidelines for deriving numerical national water-quality criteria for the protection of aquatic organisms and their uses. Data on the short-term (acute) effects of cadmium on North American freshwater species that were suitable for criteria derivation were located for 69 species representing 57 genera and 33 families. For longer-term (chronic) effects of cadmium on North American freshwater species, suitable data were located for 28 species representing 21 genera and 17 families. Both the acute and chronic toxicity of cadmium were dependent on the hardness of the test water. Hardness-toxicity regressions were developed for both acute and chronic datasets so that effects data from different tests could be adjusted to a common water hardness. Hardness-adjusted effects values were pooled to obtain species and genus mean acute and chronic values, which then were ranked by their sensitivity to cadmium. The four most sensitive genera to acute exposures were, in order of increasing cadmium resistance, Oncorhynchus (Pacific trout and salmon), Salvelinus ('char' trout), Salmo (Atlantic trout and salmon), and Cottus (sculpin). The four most sensitive genera to chronic exposures were Hyalella (amphipod), Cottus, Gammarus (amphipod), and Salvelinus. Using the updated datasets, hardness dependent criteria equations were calculated for acute and chronic exposures to cadmium. At a hardness of 50 mg/L as calcium carbonate, the criterion maximum concentration (CMC, or 'acute

Short-Term Effects of the 2008 High-Flow Experiment on Macroinvertebrates in Colorado River Below Glen Canyon Dam, Arizona

USGS Publications Warehouse

Rosi-Marshall, Emma J.; Kennedy, Theodore A.; Kincaid, Dustin W.; Cross, Wyatt F.; Kelly, Holly A.W.; Behn, Kathrine A.; White, Tyler; Hall, Robert O.; Baxter, Colden V.

2010-01-01

Zealand mud snails) and Gammarus lacustris (scuds or side-swimmers)-and also biomass reductions of other common taxa (worms in the families Lumbricidae and Tubificidae). Invertebrate drift estimates during the HFE suggest that reductions in biomass of some taxa were because of export from the reach. Reductions in biomass of P. antipodarum and G. lacustris persisted at least 15 months after the HFE, when this study concluded, and coincided with a significant decline in the annual production of these taxa: P. antipodarum production of 11 to 13 g AFDM/m2/yr in two pre-HFE years versus 2 g AFDM/m2/yr in the post-HFE year, and G. lacustris production of 7 to 8 g AFDM/m2/yr in two pre-HFE years versus 3 g AFDM/m2/yr in the post-HFE year. There were not changes in invertebrate feeding habits in response to the HFE, as our 3-year dataset of invertebrate diets indicated no substantial changes. Our long-term analysis of the composition of the drift indicates that because of a reduction in P. antipodarum in the drift relative to digestible taxa, the quality of the drift as a food resource for fishes increased. At downstream sites, total assemblage biomass did not decline, likely because assemblages were dominated by blackflies (Simulium arcticum), which were not affected by the HFE. Similar to RM 0, G. lacustris and Tubificidae had significantly lower biomass after the HFE at RM 62 and RM 225. Chironomids were also significantly lower following the flood at both downstream sites. Our findings demonstrate that the effects of a HFE on invertebrates may persist up to at least 15 months in the clear tailwater below the dam, whereas in downstream reaches impacts were more short lived. If controlling the abundance of P. antipodarum is a goal of managers, our findings indicate that periodic HFEs on the order of every 2 to 3 years may be an effective strategy for meeting that goal. More frequent HFEs may cause a shift in the state of the benthic invertebrate assemblage of the tailwa