Does pre-exposure to polluted sediment affect sub-cellular to population-level responses to contaminant exposure in a sentinel species?

Understanding how key-species respond to anthropogenic stress such as chemical pollution is critical for predicting ecosystem changes. Little is however known about the intra-specific variability in the physiological and biochemical traits involved in contaminant exposure responses. Here, we explored this idea by exposing the Baltic amphipod Monoporeia affinis from two sites, one moderately polluted and one more pristine, to a sediment spiked with PAHs and PCBs.

High capacity for a dietary specialist consumer population to cope with increasing cyanobacterial blooms.

We present a common-garden experiment to examine the amphipod Monoporeia affinis, a key deposit-feeder in the Baltic Sea, a low diversity system offering a good model for studying local adaptations. In the northern part of this system, the seasonal development of phytoplankton is characterized by a single diatom bloom (high nutritional quality), whereas in the south, the diatom bloom is followed by a cyanobacteria bloom (low nutritional quality) during summer. Therefore, the nutrient input to the benthic system differs between the sea basins.

Nitrogen isotope composition of amino acids reveals trophic partitioning in two sympatric amphipods.

According to ecological theory, two species cannot occupy the same niche. Using nitrogen isotope analyses (δN) of amino acids, we tested the extent to which two sympatric deposit-feeding amphipods, and , partition their trophic resources. We found that trophic position (TP) and resynthesis index (∑V; a proxy for degradation status of ingested material prior to assimilation by the consumer) differ between species.