Macroplastic litter colonization by stream macroinvertebrates relative to that of plant litter: A meta-analysis.

Environmental pollution by anthropogenic litter is a global concern, but studies specifically addressing the interaction between macroplastics and macroinvertebrates in streams are scarce. However, several studies on plant litter decomposition in streams have also used plastic strips as a methodological approach to assess if macroinvertebrates colonize plant litter mostly as a substrate or a food resource. Looking at these studies from the plastic strips perspective may provide useful information on the interaction between macroplastics and macroinvertebrates in streams. I carried out a meta-analysis of 18 studies that have compared macroinvertebrate colonization of macroplastic litter and plant litter in streams to estimate the overall macroinvertebrate colonization of macroplastic litter relative to plant litter, and identify moderators of this difference. Macroinvertebrate colonization of macroplastic litter was overall lower (by âˆ¼ 40%) compared with plant litter. However, differences in macroinvertebrate colonization between macroplastic litter and plant litter were observed when considering leaf litter but not wood litter, which may be a poorer substrate and food resource for macroinvertebrates. Also, differences in macroinvertebrate colonization between macroplastic litter and leaf litter were observed for shredders, collectors and predators, but not for grazers that may feed on the biofilm developed on macroplastics. Macroplastic litter supported lower macroinvertebrate density, biomass, abundance, and richness, but higher macroinvertebrate diversity than leaf litter. Higher macroinvertebrate diversity on macroplastic litter may have occurred when macroplastics represented more heterogeneous substrates (e.g., mixture of plastic types) than leaf litter (e.g., needles). Differences in macroinvertebrate abundance between macroplastic litter and leaf litter were not significantly affected by plastic type, mesh opening size, plant functional group or plant identity. By testing previously untested hypotheses, this meta-analysis guides future empirical studies. Future studies should also consider the geographical areas most affected by macroplastic pollution and the plastic types most often found in the streams.

Effects of Multiple Environmental Stressors on Zoobenthos Communities in Shallow Lakes: Evidence from a Mesocosm Experiment.

Multiple stressors, including climate change, eutrophication, and pesticide contamination, are significant drivers of the decline in lake zoobenthos. Zoobenthos play a crucial role in aquatic ecosystems, impacting energy dynamics, nutrient cycling, and sediment degradation. However, these stressors have led to a decrease in the abundance and diversity of zoobenthos, resulting in notable changes in species composition and structure. Eutrophication typically increases zoobenthos abundance while reducing taxonomic diversity. Climate change, such as warming and heatwaves, also affects the zoobenthos community structure, with different species exhibiting varying levels of adaptability to temperature changes. Additionally, pesticides like imidacloprid have negative effects on the survival and growth of zoobenthos. However, the interactions between imidacloprid and other stressors remain understudied. Here, we used 48 mesocosms (2500 L) to simulate shallow lakes. We combined nutrient loading, sustained warming, and the imidacloprid pesticide to test how these stressors interactively influence the survival and community of zoobenthos. The experimental results demonstrate that elevated temperatures have a significant impact on aquatic benthic organisms under different treatment conditions. The increase in temperature led to a notable rise in species richness and α-diversity, primarily attributed to the stimulation of metabolic activities in zoobenthos, promoting their growth and reproduction. This finding underscores the potential influence of climate change on aquatic benthic ecosystems, particularly in terms of its promoting effect on α-diversity. However, it is essential to note that elevated temperatures also reduced ß-diversity among different sites, implying a potential trend toward homogenization in zoobenthos communities under warmer conditions. Moreover, this study revealed the interactive effects of multiple stressors on the diversity of aquatic benthic communities. Specifically, the pesticide imidacloprid's impact on zoobenthos is not isolated but demonstrates complex effects within various treatment interactions. In the presence of both temperature elevation and the addition of imidacloprid, the presence of imidacloprid appears to counteract the adverse effects of temperature elevation, resulting in increased species diversity. However, when imidacloprid coincides with nutrient input, it significantly affects α-diversity negatively. These findings highlight the complexity of zoobenthos responses to multiple stressors and how these factors influence both α-diversity and ß-diversity. They provide valuable insights for further research on the conservation and management of ecosystems.

Distribution of 137Cs in the marine environment from King George Island (Southern Shetlands, maritime Antarctica).

The article presents data on the activity of the radionuclide 137Cs in seawater, sediment, macroalgae, and zoobenthos from different locations in Admiralty Bay, King George Island, maritime Antarctica. The activity of 137Cs in the macrophytobenthos remained relatively stable across species, oscillating at the level of 1 Bq kg-1dw. However, a few individuals exhibited higher activity, particularly at stations closer to the glacier front. This result could have been caused by specific conditions resulting from melting glaciers and meltwater inflow and mixing with oceanic water. The activities of 137Cs in zoobenthic were in the range from 0.12 Bq kg-1dw (Asteroidea) to 24.2 Bq kg-1dw (Porifera) and the total doses in marine species were several orders of magnitude lower than reference levels. Stable isotopes of δ13C and δ15N suggest that the main factor influencing 137Cs activity may be the source of carbon (marine vs. terrestrial/glacial), rather than feeding strategy or trophic niches.

Is Glacial Meltwater a Secondary Source of Legacy Contaminants to Arctic Coastal Food Webs?

Climate change-driven increases in air and sea temperatures are rapidly thawing the Arctic cryosphere with potential for remobilization and accumulation of legacy persistent organic pollutants (POPs) in adjacent coastal food webs. Here, we present concentrations of selected POPs in zooplankton (spatially and seasonally), as well as zoobenthos and sculpin (spatially) from Isfjorden, Svalbard. Herbivorous zooplankton contaminant concentrations were highest in May [e.g., ∑polychlorinated biphenyls (8PCB); 4.43, 95% CI: 2.72-6.3 ng/g lipid weight], coinciding with the final stages of the spring phytoplankton bloom, and lowest in August (∑8PCB; 1.6, 95% CI: 1.29-1.92 ng/g lipid weight) when zooplankton lipid content was highest, and the fjord was heavily impacted by sediment-laden terrestrial inputs. Slightly increasing concentrations of α-hexachlorocyclohexane (α-HCH) in zooplankton from June (1.18, 95% CI: 1.06-1.29 ng/g lipid weight) to August (1.57, 95% CI: 1.44-1.71 ng/g lipid weight), alongside a higher percentage of α-HCH enantiomeric fractions closer to racemic ranges, indicate that glacial meltwater is a secondary source of α-HCH to fjord zooplankton in late summer. Except for α-HCH, terrestrial inputs were generally associated with reduced POP concentrations in zooplankton, suggesting that increased glacial melt is not likely to significantly increase exposure of legacy POPs in coastal fauna.

Microplastic Interactions and Possible Combined Biological Effects in Antarctic Marine Ecosystems.

Antarctica and the Southern Ocean are the most remote regions on Earth, and their quite pristine environmental conditions are increasingly threatened by local scientific, tourism and fishing activities and long-range transport of persistent anthropogenic contaminants from lower latitudes. Plastic debris has become one of the most pervasive and ubiquitous synthetic wastes in the global environment, and even at some coastal Antarctic sites it is the most common and enduring evidence of past and recent human activities. Despite the growing scientific interest in the occurrence of microplastics (MPs) in the Antarctic environment, the lack of standardized methodologies for the collection, analysis and assessment of sample contamination in the field and in the lab does not allow us to establish their bioavailability and potential impact. Overall, most of the Southern Ocean appears to be little-affected by plastic contamination, with the exception of some coastal marine ecosystems impacted by wastewater from scientific stations and tourist vessels or by local fishing activities. Microplastics have been detected in sediments, benthic organisms, Antarctic krill and fish, but there is no clear evidence of their transfer to seabirds and marine mammals. Therefore, we suggest directing future research towards standardization of methodologies, focusing attention on nanoplastics (which probably represent the greatest biological risks) and considering the interactions of MPs with macro- and microalgae (especially sea-ice algae) and the formation of epiplastic communities. In coastal ecosystems directly impacted by human activities, the combined exposure to paint chips, metals, persistent organic pollutants (POPs), contaminants of emerging interest (CEI) and pathogenic microorganisms represents a potential danger for marine organisms. Moreover, the Southern Ocean is very sensitive to water acidification and has shown a remarkable decrease in sea-ice formation in recent years. These climate-related stresses could reduce the resilience of Antarctic marine organisms, increasing the impact of anthropogenic contaminants and pathogenic microorganisms.

A comparative study of biota and sediments as monitors of plutonium in the Yenisei River (Siberia, Russia).

MOX-fuel production and spent nuclear fuel reprocessing started recently at the Mining-and-Chemical Combine (MCC, Zheleznogorsk, Russia) have caused an increase in controlled releases of plutonium to the Yenisei River. In this study, we analyzed time-dependent trends of plutonium (239,240Pu and 238Pu) in biota and bottom sediments of the Yenisei during 2008-2019, to estimate comparatively the potential of abundant representatives of biota as bio-monitors of contamination of the Yenisei by plutonium. Gamma-emitting radionuclides (40 K; 60Co; 137Cs; 152Eu; 241Am) were measured in environmental samples of the Yenisei as well. Samples of bottom sediments, water moss (Fontinalis antipyretica), shining pondweed (Potamogeton lucens), caddisfly larvae with casings (Apatania crymophila), and amphipods (Eulimnogammarus viridis and Palaseopsis cancelloides) were collected downstream and upstream of the radioactive discharge site. Environmental samples of the Yenisei collected downstream of the radioactive discharge site differed considerably in activity concentrations of plutonium but were similar in time-dependent trends of plutonium, reflecting the trends of annual discharges of plutonium. In 2018, the year of a sharp increase in controlled discharge of plutonium, the concentration of 239,240Pu in water moss (26 Bq kg-1 d.w.) was higher than in sediments (14 Bq kg-1 d.w.). In other years, the highest activity concentration of 2391,240Pu was observed in bottom sediments. In view of the higher magnitude of increase in plutonium concentration, water moss and shining pondweed can be considered as more sensitive indicators of increased fresh releases of plutonium than bottom sediments. Taking into account the food-related mechanism of plutonium uptake by amphipods, this representative of biota can be regarded as a sensitive monitor of bioavailable plutonium in the Yenisei.

Eutrophication causes invertebrate biodiversity loss and decreases cross-taxon congruence across anthropogenically-disturbed lakes.

Eutrophication is a major problem currently impacting many surface water ecosystems. Impacts of increased nutrient concentrations on biodiversity may differ between different scales, different organism groups, and different trophic states. Surveys at different spatial scales have suggested that biodiversity of different taxa may exhibit significant cross-taxon congruence. In our study, we examined the diversity of zooplankton and zoobenthos across 261 lakes in the Lake Taihu watershed, an area that is undergoing a severe eutrophication process. We tested the cross-taxon congruence in species richness and Shannon-Wiener diversity between zooplankton and zoobenthos along a nutrient gradient across the lakes. Our findings were consistent with the intermediate disturbance hypothesis, considering nutrient input as the disturbance. Also, we found significant cross-taxon congruence between zooplankton and zoobenthos diversities. Our results confirmed that excess nutrient levels resulted in diversity loss and community simplification. Zoobenthos were more sensitive to nutrient increases compared with zooplankton, which decreased cross-taxon congruence because these organism groups did not respond similarly to the anthropogenic disturbance.

All Shades of Shrimp: Preferences of Colour Morphs of a Freshwater Shrimp Neocaridina davidi (Decapoda, Atyidae) for Substrata of Different Colouration.

An ornamental freshwater shrimp, Neocaridina davidi, is popular as an aquarium hobby and, therefore, a potentially invasive species. There is a growing need for proper management of this species to determine not only their optimum breeding conditions, but also their ability to colonise novel environments. We tested habitat preferences of colour morphs (brown, red, white) of N. davidi for substratum colour (black, white, grey shades, red) and fine or coarse chess-board patterns to recognise their suitable captivity conditions and predict their distribution after potential release into nature. We conducted laboratory choice experiments (n = 8) with three individuals of the same morph exposed for two hours to a range of backgrounds. Shrimp preferred dark backgrounds over light ones irrespective of their own colouration and its match with the background colour. Moreover, the brown and red morphs, in contrast to the white morph, preferred the coarse background pattern over the finer pattern. This suggests that the presence of dark, uniform substrata (e.g., rocks, macrophytes) will favour N. davidi. Nevertheless, the polymorphism of the species has little effect on its total niche breadth, and thus its invasive potential.

Diet influence on mercury bioaccumulation as revealed by polyunsaturated fatty acids in zoobenthos from two contrasting environments: Chinese reservoirs and Swedish lakes.

The bioaccumulation of mercury (Hg) and polyunsaturated fatty acids (PUFA) in zoobenthos varies across aquatic food webs. In this field study, contents of total Hg (THg), methylmercury (MeHg) and PUFA were investigated in zoobenthos of Chinese reservoirs and Swedish lakes, with contrasting environmental characteristics and algal diet sources, which can result in difference of Hg and PUFA in zoobenthos from these two habits. Using PUFA as dietary biomarkers of algae in zoobenthos, we evaluated effects of environmental factors and algal diet sources on the accumulation of THg, MeHg, and the highly required PUFA eicosapentaenoic (EPA, 20: 5n-3) and docosahexaenoic acid (DHA, 22:6n-3) in zoobenthos. Average THg and MeHg in zoobenthos were higher in Chinese reservoirs than Swedish lakes (p < 0.05). Average EPA content of zoobenthos was similar in these two habitats (p > 0.05), yet average DHA content of zoobenthos was higher in Chinese reservoirs than Swedish lakes (p < 0.05). Total Hg and MeHg contents of zoobenthos in Swedish lakes were predicted by environmental factors; e.g., negatively with pH and positively with dissolved organic carbon (DOC) concentrations, yet had no significant relationship with the algal dietary. In Chinese reservoirs, however, no environmental factor correlated well with THg contents in zoobenthos, and only DOC concentrations showed positive correlation with MeHg contents in zoobenthos. Besides, the algal dietary was also positively correlated with MeHg contents in zoobenthos. EPA and DHA contents of zoobenthos in Swedish lakes primarily associated with algal diet. By contrast, in Chinese reservoirs, EPA and DHA contents of zoobenthos were affected by both environmental factors and algal diet.

Geological and hydrochemical prerequisites of unexpectedly high biodiversity in spring ecosystems at the landscape level.

This study explores the factors affecting the biodiversity of diatoms, vegetation with focus on bryophytes, and invertebrates with focus on water mites, in a series of 16 spring-habitats. The springs are located primarily from the mountainous part of the Emilia-Romagna Region (Northern Apennines, Italy), and two pool-springs from agricultural and industrial lowland locations. Overall, data indicate that biological diversity (Shannon-Wiener, α-diversity) within individual springs was relatively low, e.g.: Sdiatoms = 0-46, Swater-mites = 0-11. However, when examined at the regional scale, they hosted a very high total number of taxa (γ-diversity; Sdiatoms = 285, Swater-mites = 40), including several new or putatively-new species, and many Red-List taxa. This pattern suggested there is high species turnover among springs, as well as high distinctiveness of individual spring systems. A key goal was to assess the hydrogeological and hydrochemical conditions associated with this high regional-pool species richness, and to provide a guide to future conservation strategies. There was a striking variety of geological conditions (geodiversity, captured mainly with lithotype and aquifer structure) across the study region, which led to wide variation in the hydrosphere, especially in conductivity and pH. Agriculture and industrial activities (anthroposphere) in the lowlands resulted in nutrient enrichment and other forms of pollution. Across all 16 spring-systems, several hydrogeological conditions most strongly influenced the presence or absence of particular biota and were determinants of species importance: spring-head morphology, hydroperiod, discharge, current velocity, and elemental concentration. These findings have important practical consequences for conservation strategies. Our data show that it is imperative to protect entire regional groups of springs, including representatives of the different ecomorphological spring types, lithologies, and degrees of human influence. These findings suggest that springs, when studied from an ecohydrogeological perspective, are excellent systems in which to further investigate and understand geo-biodiversity relationships.

Effects of climate warming and nitrogen deposition on subtropical montane ponds (central China) over the last two centuries: Evidence from subfossil chironomids.

Many remote montane ecosystems are experiencing biogeochemical changes driven by warming climate and atmospheric pollution. Compared with circumpolar and temperate lakes, the responses of subtropical montane lakes to these external stressors have been less investigated. Here we present sedimentary multi-proxies records (i.e. chironomids, elements and stable isotope of carbon and nitrogen) in 210Pb-dated cores from two montane ponds (central China). Before the 1900s, low biomass and the dominance of opportunistic species (e.g. Chironomus anthracinus-type) in both ponds might be in response to cold and harsh condition. Thereafter, chironomid communities in both ponds experienced pronounced shifts. Nutrient-tolerant/warm-adapted species (e.g. Chironomus sp., Polypedilum nubeculosum-type and Endochironomus impar-type) proliferated and biomass increased synchronously after the 1900s, suggestive of favorable condition for chironomid growth. Redundancy analyses revealed that changes in chironomid communities in both ponds were significantly correlated with rising temperature and δ15N depletion. Prolonged growing season and nitrogen subsidy would increase primary productivity, and hence enhancing food availability for chironomids. Catchment-mediated indirect effects of warming and nitrogen deposition, such as hydrological changes and terrestrial organic matter inputs, would impose further influences on chironomid communities. Taken together, the combined effects of climate warming and nitrogen deposition have caused significant shifts in primary consumers of these montane ponds, and imposed cascading effects on structure and function of subtropical montane aquatic ecosystems.

Spatiotemporal distribution dynamics of heavy metals in water, sediment, and zoobenthos in mainstream sections of the middle and lower Changjiang River.

Water, sediment, and zoobenthos are crucial carriers and storage media for heavy metal migration and transformation. The distribution characteristics of heavy metals in water, sediment, and zoobenthos can reflect their pollution status and potential influences on the health of aquatic ecosystems. On the basis of monitoring data related to Cu, Zn, Pb, Cd, Ni, Mn, Hg, and As in mainstream water, surface sediment, and zoobenthos at eight sections-from Wuhan to Shanghai-of the Changjiang River (also known as the Yangtze River) and historical monitoring data on heavy metal distributions in different environmental media of the Changjiang River since the 1980s, this study undertook systematically analyzed the spatiotemporal distribution dynamics, pollution levels, and corresponding environmental risks related to heavy metals in water, sediment, and biota, and examined the effects of pollution source variations and water and sediment regimes on heavy metal distribution. Heavy metal concentrations in the waters were much lower than the water quality threshold of Grade III of the Chinese Surface Water Environmental Quality Standard (GB3838-2002); the concentrations of different heavy metals were irregularly distributed and varied significantly along the river mainstream; Cu, Cd, Zn, and Pb concentrations in sediment all exceeded their respective critical effect concentrations and exposed the ecosystem to pollution risks; the pollution levels of and ecosystem health risks posed by Zn and Cu in zoobenthos were high, with pollution concentrations ranked as shrimp > snails > crabs. In general, heavy metal concentrations in the three environmental mediums were ranked as sediment > zoobenthos > water. Finally, comparison with historical monitoring data revealed increasing Cd and Hg concentrations, with the average heavy metal concentration in sediment reaching its maximum value in the 2000s in the middle and lower reaches of the Changjiang River, which are subjected to the combined effect of pollutant emissions and changing water and sediment regimes.

Climate-driven changes in macrobenthic communities in the Mediterranean Sea: A 10-year study in the Bay of Banyuls-sur-Mer.

Marine ecosystems worldwide are affected by both natural variation and human activities; to disentangle and understand their individual role in influencing the macrobenthic community composition is challenging. The relationship between interannual variability in atmospheric circulation, dictated by the climatic oscillation indices, and the benthic macrofauna composition was assessed at four sampling sites located in the Bay of Banyuls-sur-Mer (NW Mediterranean Sea). Between 2004 and 2013, these sites were sampled annually during autumn/winter and analyzed for sediment grain-size and benthic macrofauna composition (species richness, abundance, and biomass). Temporal changes in these descriptors were correlated with two climatic indices (NAO and WeMO indices) and a set of environmental parameters integrated over three different time periods (i.e., whole year, springtime, and wintertime). Our results confirm the occurrence of major temporal changes in the composition of macrobenthic communities within the Gulf of Lions. More specifically, the results indicate that (a) the WeMO appears to be more closely related to benthic macrofauna composition in the Bay of Banyuls-sur-Mer than the NAO, (b) winter is a better integration period than spring or the whole year as a proxy for community composition changes, and (c) Rhône River water flow is likely involved in the control of benthic macrofauna composition in the whole Gulf of Lions. The present study highlights the importance of WeMO as a regional proxy, which can be used to evaluate changes in benthic macrofauna linked to climatic variability.

Impact of Water Pollution on Trophic Transfer of Fatty Acids in Fish, Microalgae, and Zoobenthos in the Food Web of a Freshwater Ecosystem.

This research work was carried out to determine the effects of water contamination on the fatty acid (FA) profile of periphyton, zoobenthos, two Chinese carps and a common carp (Hypophthalmichthys molitrix, Ctenopharygodon idella and Cyprinus carpio), captured from highly polluted (HP), less polluted (LP), and non-polluted (NP) sites of the Indus river. We found that the concentration of heavy metals in the river water from the polluted locations exceeded the permissible limits suggested by the World Health Organization (WHO) and the US Environmental Protection Agency (EPA). Fatty acid profiles in periphyton, zoobenthos, H. molitrix, C. idella, and C. carpio in the food web of river ecosystems with different pollution levels were assessed. Lauric acid and arachidic acids were not detected in the biomass of periphyton and zoobenthos from HP and LP sites compared to NP sites. Alpha-linolenic acid (ALA), eicosadienoic acid and docosapentaenoic acid were not recorded in the biomass samples of periphyton and zoobenthos in both HP and LP sites. Caprylic acid, lauric acid, and arachidic acid were not found in H. molitrix, C. idella, and C. carpio captured from HP. In this study, 6 and 9 omega series FAs were identified in the muscle samples of H. molitrix, C. idella and C. carpio captured from HP and LP sites compared to NP sites, respectively. Less polyunsaturated fatty acids were observed in the muscle samples of H. molitrix, C. idella, and C. carpio collected from HP than from LP. The heavy metals showed significant negative correlations with the total FAs in periphyton, zoobenthos, and fish samples.

Impact assessment of an effluent discharge on benthic macroinvertebrates in a subtropical river using indexes

Benthic macroinvertebrates are used as environmental bioindicators in the assessment of water quality in rivers and lakes, due to the sensitivity of some taxa to pollution. The objective of this research was to evaluate the consequences of industrial effluent discharge on the structure of the benthic community present in a river in the subtropical region of Brazil. The organisms were collected at three points of the Coutinho River, in 2013 (September and November) and 2014 (January and March). To characterize the community were calculated density, Shannon diversity index (H ́), Pielou equitability (J), taxa richness, Biotic Indices (Biological Monitoring Working Party - BMWP, Average Score Per Taxon - BMWP-ASPT, Family Biotic Index – FBI) and Canonical Correspondence Analysis (CCA) between sampling points and biotic and abiotic variables. Fifteen taxa were identified and among the collected organisms, the family Chironomidae was the most representative, followed by Oligochaeta, Hirudinea, Bivalvia, Gastropoda. According to the results of the biological indices, point 1 indicated moderate pollution and the following points (2 and 3) showed severe pollution. These indices showed poor waters with a high degree of pollution. The results were efficient in detecting the environmental impacts suffered by the river and suggest the necessity of a continuous monitoring of the same.

Four decades of functional community change reveals gradual trends and low interlinkage across trophic groups in a large marine ecosystem.

The rate at which biological diversity is altered on both land and in the sea, makes temporal community development a critical and fundamental part of understanding global change. With advancements in trait-based approaches, the focus on the impact of temporal change has shifted towards its potential effects on the functioning of the ecosystems. Our mechanistic understanding of and ability to predict community change is still impeded by the lack of knowledge in long-term functional dynamics that span several trophic levels. To address this, we assessed species richness and multiple dimensions of functional diversity and dynamics of two interacting key organism groups in the marine food web: fish and zoobenthos. We utilized unique time series-data spanning four decades, from three environmentally distinct coastal areas in the Baltic Sea, and assembled trait information on six traits per organism group covering aspects of feeding, living habit, reproduction and life history. We identified gradual long-term trends, rather than abrupt changes in functional diversity (trait richness, evenness, dispersion) trait turnover, and overall multi-trait community composition. The linkage between fish and zoobenthic functional community change, in terms of correlation in long-term trends, was weak, with timing of changes being area and trophic group specific. Developments of fish and zoobenthos traits, particularly size (increase in small size for both groups) and feeding habits (e.g. increase in generalist feeding for fish and scavenging or predation for zoobenthos), suggest changes in trophic pathways. We summarize our findings by highlighting three key aspects for understanding functional change across trophic groups: (a) decoupling of species from trait richness, (b) decoupling of richness from density and (c) determining of turnover and multi-trait dynamics. We therefore argue for quantifying change in multiple functional measures to help assessments of biodiversity change move beyond taxonomy and single trophic groups.

Trait-based predation suitability offers insight into effects of changing prey communities.

Increasing environmental pressures and human impacts are reshaping community structures and species interactions throughout all trophic levels. The morphological and behavioural characteristics of species communities contain key ecological information on why prey species appear attractive to predators but are rarely applied when exploring predator-prey (PP) relationships. Expanding our knowledge on how changing prey communities can alter the food resource suitability (RS) for predators is vital for understanding PP dynamics in changing ecosystems. Detailed predator diet data are commonly restricted to commercially important species and often not available over long temporal scales. To find out whether structural changes of prey communities impact the food RS for predator communities over space and time, we apply a novel framework to describe and interpret changes in predator diet-suitability based on predation-relevant traits of prey. We use information on described feeding links from the literature to compile the prey spectrum for each predator and subsequently translate the prey-species into a prey-trait spectrum. For each predator, we then calculate a frequency-based prey-trait affinity score and relate it to the available food resource pool, the community weighted means of prey traits, resulting in a prey-suitability measure. We aim to reveal whether a described multi-decadal change in the community structure of zoobenthos had an impact on the food suitability for the benthic-feeding fish in a coastal system of the Baltic Sea. We assess the direction of change in resource quality from the perspective of benthic-feeding fish and describe predator-specific responses to examine which species are likely to profit or be disadvantaged by changes in their prey spectrum. Furthermore, we test the relationship between functional diversity of prey communities and food suitability for predators, and whether predation linkage-structures are affected through prey community-changes. Our results show that changes in zoobenthic communities had a positive effect on the food suitability for most benthic-feeding fish, implying more suitable food resources. Species-specific responses of predators suggest varying plasticity to cope with prey assemblages of different trait compositions. Additionally, the functional diversity of zoobenthos had a positive effect on the food suitability for predator fish. The changing trait compositions of prey influenced the PP linkage-structure, indicating varying specialisation of benthic feeding fish towards available food resources. Our findings suggest that changing morphological characteristics of prey can impact food RS features for its predators. This approach enables long-term evaluation of prey quality characteristics where no detailed diet data is available and allows for cross-system comparison as it is not relying on taxonomic identities per se.

Effects of food availability and habitat features on the Ephemeroptera species composition at seasonal and spatial scales from neotropical floodplain rivers / Efeitos da disponibilidade de alimento e características do habitat sobre a composição de espécies de Ephemeroptera nas escalas sazonal e espacial de rios de planície neotropicais

Abstract Brazilian floodplains have suffered great changes in their natural characteristics in recent decades, mainly in the flood pulse. The Upper Paraná River floodplain is one of the few places where are found remained areas in which such peculiar characteristics keep reflecting on its high biodiversity. Ephemeroptera nymphs are one of the higher density groups among benthic community, occurring in many water bodies like large rivers and secondary channels. We sought to understand which factors are needed for the species establishment and how much important is the species colonization, especially in environments with anthropogenic changes. The marginal areas, which are more structured with presence of macrophytes, showed the highest density and richness even in the Paraná River that has great human impact. We verified dominance of Americabaetis alphus, Tricorythopsis araponga, Tricorythopsis artigas on the Parana River, correlated with transparency, depth and electric conductivity, while the dominance of Traverella sp. was correlated with water temperature, especially in marginal areas. Consequently, the increasing transparency and electric conductivity due to the Porto Primavera dam in Parana River can be favoring those Ephemeroptera species. We demonstrated the importance of preserving the wetlands of Ivinhema River State Park mainly for Guajirolus sp., which was only registered in this region. Therefore, our study provides support for understanding gaps from previously studies using artificial substrates in three large rivers which are of great importance to the upper Paraná River floodplain.

Resumo Muitas planícies de inundação brasileiras vêm sofrendo enormes alterações em suas características naturais nas últimas décadas, principalmente no pulso de inundação. A planície de inundação do alto rio Paraná é um dos poucos lugares onde ainda há áreas nas quais essas características peculiares se mantêm, o que reflete em sua alta biodiversidade. Dentre a comunidade zoobentônica, Ephemeroptera é um dos grupos com maior densidade, ocorrendo em diversos corpos aquáticos como rios de grande porte e canais secundários. Nós buscamos compreender quais fatores são necessários para o estabelecimento das espécies e o quão importante é a colonização dessas espécies, principalmente em ambientes com modificações antrópicas. As áreas marginais mais estruturadas com presença de macrófitas apresentaram altas densidade e riqueza mesmo no rio Paraná que apresenta grande impacto antrópico. Verificamos que as dominâncias de Americabaetis alphus, Tricorythopsis araponga e Tricorythopsis artigas no rio Paraná foram correlacionadas com maiores valores de transparência, profundidade e condutividade, enquanto que a dominância de Traverella sp. foi correlacionada com temperatura, principalmente em áreas marginais. Consequentemente, o aumento da transparência e da condutividade devido à barragem de Porto Primavera no rio Paraná pode estar favorecendo essas espécies de Ephemeroptera. Nossos resultados demonstram a importância da preservação do Parque nacional das várzeas do rio Ivinhema, principalmente para o gênero Guajirolus sp., o qual apenas foi registrado nessa região. Portanto, nosso estudo vem trazer subsídios para compreensão de lacunas verificadas em estudos anteriores utilizando substratos artificiais em três rios de enorme influência na planície de inundação do alto rio Paraná.

Natural variability of biochemical biomarkers in the macro-zoobenthos: Dependence on life stage and environmental factors.

Biomarkers are widely used in ecotoxicology as indicators of exposure to toxicants. However, their ability to provide ecologically relevant information remains controversial. One of the major problems is understanding whether the measured responses are determined by stress factors or lie within the natural variability range. In a previous work, the natural variability of enzymatic levels in invertebrates sampled in pristine rivers was proven to be relevant across both space and time. In the present study, the experimental design was improved by considering different life stages of the selected taxa and by measuring more environmental parameters. The experimental design considered sampling sites in 2 different rivers, 8 sampling dates covering the whole seasonal cycle, 4 species from 3 different taxonomic groups (Plecoptera, Perla grandis; Ephemeroptera, Baetis alpinus and Epeorus alpicula; Tricoptera, Hydropsyche pellucidula), different life stages for each species, and 4 enzymes (acetylcholinesterase, glutathione S-transferase, alkaline phosphatase, and catalase). Biomarker levels were related to environmental (physicochemical) parameters to verify any kind of dependence. Data were statistically elaborated using hierarchical multilevel Bayesian models. Natural variability was found to be relevant across both space and time. The results of the present study proved that care should be paid when interpreting biomarker results. Further research is needed to better understand the dependence of the natural variability on environmental parameters. Environ Toxicol Chem 2017;36:3158-3167. © 2017 SETAC.

Arsenic Speciation in Organisms from two Large Shallow Freshwater Lakes in China.

This study measured the elemental and species concentrations of arsenic (As) in the water, sediments and food webs of two shallow Chinese freshwater lakes. Organic As species were widely detected in various organisms from the two lakes (60%-100% of the total). Among these organisms, dimethylarsinic acid (DMA) was predominant in most of the samples. The average concentrations and corresponding proportions were 0.59 mg/kg, 81% in fish; 3.24 mg/kg, 70.63% in zoobenthos; and 1.34 mg/kg, 79% in plants. The average concentrations and corresponding proportions of monomethylarsonic acid (MMA) and inorganic As were much lower, ranging from n.d. (not detected) to 1.94 mg/kg and from n.d. to 1.54 mg/kg, with an average proportion of 14 and 7.4%, respectively. In Lake Taihu, the mean As concentrations in different fish tissues were generally low and in the following order: eggs (0.47) < skin (0.62) < muscles (0.91) < gills (1.65) < livers (5.47) mg/kg. DMA occupied 75%-100% of the total As species, while MMA and inorganic As were much less prevalent.