Ecological importance of parasitic infections for the functioning of coastal soft-bottom environments in more acid and warmer waters – PICAWAWA

Benthic ecosystem engineer species play a key role in the structure and functioning of coastal ecosystems that are currently threatened by global change. Rising ocean temperature (ocean warming) and decreasing pH (ocean acidification) can have a substantial impact on those species with cascading effects on their engineering role. Higher temperature could also promote parasitism pressure on these influential organisms. Parasites are ubiquitous components of coastal systems but their functional importance has largely been overlooked because they are small and inconspicuous. In particular, studies assessing the sub-lethal effects of parasites on marine engineer species and how these reverberate on ecosystem function and structure are extremely scarce, and none has been conducted in a global change context. Predicting the importance of parasites for marine ecosystem functioning in warmer and more acid waters is thus still a major scientific challenge. It requires consideration of (1) direct individual effects of ocean acidification and warming on host-parasite associations, (2) their interactive effects, and (3) how changes in host-parasite relationships resound at higher functional levels of organization (population, community). The project PICAWAWA will use both field surveys and ex-situ experimental work to conduct research at the intersection of marine parasitology, functional ecology and global change ecology, providing new insights onto the non-lethal effects of parasitism and global change on a benthic ecosystem engineer and knock-on effects on coastal ecosystem functioning using a multi-scale approach. PICAWAWA will (1) build for a holistic understanding of the functioning of coastal soft-bottom ecosystems and, (2) reveal how increasing parasitic pressure and global change will alter emergent properties of coastal systems through component responses.