New Publications

Are interactive effects of harmful algal blooms and copper pollution a concern for water quality management?

water researchCyanobacteria, commonly known as harmful algae due to their adverse effects on aquatic organisms, are a major concern to water quality. While it is well-known that cyanobacteria reduce the fitness of Daphnia sp., their combined effects with chemicals have hardly been documented. In our recent paper, we investigate how cyanobacteria act together with copper, commonly used in algaecides and fungicides, to impact the model organism Daphnia. The results show that cyanobacteria and copper together can considerably impair daphnid reproduction but that their combined effects are overall close to expectations based on their individual toxicities and hence of limited concern for water quality management.

Environmental effects on fished lobsters and crabs

reviewsinfish

In times of climate change, when the sea temperatures are increasing in the world oceans, and ocean acidification is becoming and increasing concern, information of environmental effects on key life history stages of important species is important and needs to be readily available. Lobsters and crabs are key commercial species, and due to their complex life cycle different environmental variable may have dissimilar effects on their abundance, depending on the life stage considered. This review will be very valuable for managers, fishermen as well as scientists alike.

 

The ChimERA project: coupling mechanistic exposure and effect models into an integrated platform for ecological risk assessment

EnvSciPol

Typically, environmental exposure and the expected ecological effects are assessed separately. Yet for the last 25 years, the environmental realism, the ecological relevance, and the methodological accuracy of these official procedures have been questioned. Bearing in mind the ecological and environmental complexity inherent to natural ecosystems, risk assessors increasingly realise that ecological risk cannot be adequately assessed while disregarding most, if not all, of this complexity. Exposure to chemicals is not constant in time nor is it homogeneously distributed in space. This may allow for recovery-inducing processes at the individual, population, and community level. In addition, real ecosystems may be faced with the combined effects of multiple stressors. Moreover, this approach neglects that functional redundancy may compensate species loss and sustain functions in stressed ecosystems. Experimentally examining the effects of multiple stressors at higher levels of biological organisation from multiple exposure scenarios in various geographical areas is an informative exercise but cannot be considered as a standard approach for ERA. Instead, new models are needed which can be extrapolated to many different alternative scenarios. In this paper, we outline the methodology and objectives of a new project which will answer this need.

Toxicity data for modeling impacts of oil components in an Arctic ecosystem

10646Today, modeling has become an invaluable tool to extrapolate impacts of toxicants from an individual to the population level. As such, it is essential for ecosystem-based approaches to impact assessment. For modelling purposes, this study synthesized available literature on the effects of petroleum related discharges on selected cold-water marine species (plankton and fish). The resulting dataset is to be used by ecotoxicology algorithms included in an ecosystem-based modeling system that combines both ecological and toxicological knowledge into a single modeling framework. We believe this study is of general value to the ecotoxicology community in two ways: first, the assembled data are of use to others engaged in the development and/or application of ecotoxicology models. Second, the results indicate where further ecotoxicology research will be of greatest value for both increasing general knowledge on cold-water ecotoxicology and for designing new ecotoxicology studies for modeling applications.

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

10646Alien invasive species (AIS) are, next to global change, considered to be one of the major threats to global biodiversity. Globalisation and habitat deterioration positively contribute to the establishment success of AIS. Besides appropriate vectors of introduction and favourable environmental conditions their success can be attributed to species specific traits such as a high reproduction rate, an omnivorous diet and the ability to easily cope with changing environmental conditions. In this study, we hypothesized that AIS are more tolerant to metal pollution compared to native species. We tested this hypothesis based on a comparison between native and alien freshwater shrimps that were exposed to different concentrations of cadmium. We found significant differences in sensitivity to metal pollution between different species which should be taken into consideration in environmental risk assessment and water quality standard setting. There was no clear trend in Cd sensitivity between native and alien shrimps, indicating that alien species do not have an advantage over native ones in cadmium contaminated waters.  

Latest study on gene-expression respones in the waterflea to combined stressors featured on ChemicalWatch.com

ESnT

Genetic responses to environmental chemicals do not always correlate with higher-level effects, such as growth and reproduction in aquatic test species, according to our latest study recently published in the journal Environmental Science & Technology. This finding potentially has important implications for risk assessment in relation to the Adverse Outcome Pathways (AOP) framework. AOPs try to predict responses at higher biological levels, which are more relevant for risk assessment, starting from genetic responses. ChemicalWatch.com, an online repository which provides businesses with the information they need to manage the risks of chemicals responsibly, has recognized the important value of these findings and featured the study on their website. More information can be found on ChemicalWatch.com. The website allows a free 14-day trial which gives access to the full text.

Relating taxonomy-based traits of macroinvertebrates with river sediment quality based on Basic and Zero-Inflated Poisson models

ecological informationsDue to growing anthropogenic stress on aquatic ecosystems it is important to have accurate and fast methods for environmental risk assessment. Ecological assessment of freshwaters is traditionally based on the diversity approach where diversity decreases with increasing environmental disturbance. In this paper, we propose a novel approach where modelled changes in trait composition of macroinvertebrates are used to assess the river sediment quality. We hypothesized that the trait composition, in this case the body length of the organisms, would change as metal concentrations increase. We found that the abundance of macroinvertebrate taxa decreased at almost all body lengths with a decreasing quality of the metal contaminated river sediment. It was also found that the number of different body lengths decreased with increasing metal pollution, indicating a decrease in diversity of the macroinvertebrate community. Smaller organisms seemed to be more resistant to metal pollution. This research showed that trait-based ecological risk assessment has high potential, but that possibly other traits besides body length should be included to strengthen our conclusions.

Ecotoxicity of binary mixtures of Microcystis aeruginosa and insecticides to Daphnia pulex

env pollutHarmful bluegreen algae such as cyanobacteria can have large impacts on aquatic ecosystems and ponds. Often, these cyanobacteria are not the only form of toxic stress present. In our recent paper, we study how cyanobacteria together with insecticides  used in crop protection can impact the model organism Daphnia. The results show that cyanobacteria and insecticides together can have significant effects on the reproduction of the daphnid. Depending on the type of insecticide used, these effects are  larger, smaller or equal to our expectations.

Hard X-ray nanoprobe investigations of the subtissue metal distributions within Daphnia magna

AnalBioChemTo improve our capacity to evaluate the impact of metals on aquatic organisms, the fundamental processes of uptake, elimination and detoxification need to be fully understood. To this end, the freshwater crustacean Daphnia magna has long served as a model organism for studying whole body bio-accumulation. In order to fully comprehend the active regulation of internal concentrations within aquatic biota, the toxicological research needs to move from the microscopic tissue scale towards a (sub)cellular field of view. We developped a novel sample preparation technique which, when coupled to advanced elemental imaging, reveals the distributions of Ca, Fe and Zn within D. magna at the subtissue level. The presented technique was found to be well suited for trace-level bio-imaging which may ultimately aid in the discovery of new insights in the detoxification processes within aquatic model organisms.

Additive modelling reveals spatiotemporal PCBs trends in marine sediments 

marinepollutionbulletinThe environmental fate and toxicity of persistent organic pollutants (POPs) are of global concern. Spatiotemporal trend analyses of such hazardous substances are identified as a key priority by the OSPAR commission. In this paper we analyse one of the largest, longest and most complete data sets of PCBs using a regression-based technique in order to compare the levels and time trends of marine and estuarine PCB sediment concentrations between and within the Belgian Coastal Zone (BCZ) and the Western Scheldt estuary. The time trends unraveled a two to three-fold decrease in PCB concentrations in the BCZ during the past 20 years (1991-2010). However, in the Western Scheldt estuary, time trends were spatially heterogeneous and did not exhibit a significant decrease. These results demonstrate that international efforts to reduce PCB emissions have effectively reduced concentrations in open water ecosystems like the BCZ but have not affected urbanized and industrialized areas of the Scheldt estuary. The ten PCB congeners we considered followed the same trend, suggesting that no point sources are present in our study area for these congeners.

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