New Publications

 

Sea spray aerosols (SSAs) have profound effects on our climate and ecosystems. They also contain microbiota and biogenic molecules which could affect human health. Yet the exposure and effects of SSAs on human health remain poorly studied. Here, we exposed human lung cancer cells to extracts of a natural sea spray aerosol collected at the seashore in Belgium, a laboratory-generated SSA, the marine algal toxin homoyessotoxin and a chemical inhibitor of the mammalian target of rapamycin (mTOR) pathway. 

In this study we developed a novel, mechanistic model where we predict effects of Cu on aquatic invertebrate populations (Lymnaea stagnalis – the great pond snail). Lymnaea stagnalis is particularly sensitive species to various metals 
and the precise mechanism for metal toxicity for this species are not fully understood. In this research, we extrapolated Cu toxicity effects from various studies and food sources to the population level. To improve inter-study comparability, we used a biotic ligand model to correct for the water chemistry. At the population level, the range in EC10 decreased significantly compared at the individual level. This model is the first developed at Arche Consulting and the University of Ghent where we promote the use of ecological models for the risk assessment of chemicals.

Over the past decades, the world's oceans and seas have been influenced by several human induced impacts, including climate change. Understanding the impacts of this changing environmental condition in zooplankton communities is crucial, as alterations in the zooplankton communities can affect entire marine ecosystems. Here, we focus on the potential effects of an increase in temperature on the calanoid copepod species, Temora longicornis, the dominant zooplankton species of the southern part of the North Sea. We sequenced the transcriptome (using RNA-seq technology) in T. longicornis, after being exposed to thermal stress, to investigate gene expression differences as a response to temperature fluctuations. 

Polyunsaturated fatty acids (PUFAs) have key biological roles in fish cells. We recently showed that the phospholipid composition of rainbow trout liver cells (RTL-W1 cell line) modulates their tolerance to an acute cadmium (Cd) challenge. Here, we investigated (i) the extent to which PUFAs and Cd impact fatty acid homeostasis and metabolism in these cells and (ii) possible mechanisms by which specific PUFAs may confer cytoprotection against Cd. 
We performed an environmental risk assessment for microplastics (<5 mm) in the marine environment by estimating the order of magnitude of the past, present and future concentrations based on global plastic production data. In 2100, from 9.6 to 48.8 particles m−3 are predicted to float around in the ocean, which is a 50-fold increase compared to the present-day concentrations. From a meta-analysis with effect data available in literature, we derived a safe concentration of 6650 buoyant particles m−3 below which adverse effects are not likely to occur.
The hardness values of a substantial proportion of Australian freshwaters fall below the application boundary of the existing European nickel biotic ligand models (Ni BLMs) of 2 mg Ca/L. Modifications were made to the Ni BLM by increasing the binding constants for Ca and Mg at the biotic ligand to account for softer waters encountered in Australia and the more important competitive effect of Ca and Mg on Ni toxicity.
Under natural conditions, organisms can experience a variety of abiotic (e.g., temperature, pH) and biotic (e.g., species interactions) factors, which can interact with toxicant effects. By ignoring species interactions conventional ecotoxicological studies (i.e., single‐species tests) oversimplify the actual field situation. We investigated whether temperature and interspecific competition affected the effects of zinc (Zn) on a Daphnia longispina population.
Human activities increasingly impact the functioning of marine food webs, but anthropogenic stressors are seldom included in ecological study designs. Diet quality, as distinct from just diet quantity, has moreover rarely been highlighted in food web studies in a stress context. We measured the effects of metal and pesticide stress (copper and atrazine) on the contribution of a benthic intertidal diatom community to two processes that are key to the functioning of intertidal systems: biomass (diet quantity) and lipid (diet quality) production. 

Toxicity of nickel to aquatic organisms is known to be affected by factors such as dissolved organic carbon (DOC) concentration and water hardness. Bioavailability models have been developed more than a decade ago that have been validated for European surface waters. Australian surface waters, however, are quite different in composition. This collaborative research with Australian, UK, and USA researchers resulted in slightly modified bioavailability models for a range of indigenous organisms that are shown to predict nickel toxicity in local waters relatively accurately. These models can be used in Australian water quality guideline derivations.

Environmental risk assessment of chemicals is mostly based on ecotoxicity studies under standard and not always realistic conditions of temperature and nutrient levels. In this collaborative study with universities of Wageningen, Leuven, and Namur, we performed an aquatic model ecosystem experiment, which showed that temperature and phosphorus loading to freshwater systems can modify the effects of chemical pollution on the structure (e.g. species composition) and functioning of aquatic ecosystems. We argue that factors like temperature and nutrient levels should be taken into account when evaluating the risks of chemicals in the environment.

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