Global change effects on plankton from Atlantic Patagonian coastal waters: the role of interacting drivers

VILLAFAÑE, VIRGINIA; CABRERIZO, MARCO; CARRILLO, PRESENTACIÓN; HERNANDO, MARCELO; MEDINA-SÁNCHEZ, JUAN; NARVARTE, MAITE ANDREA; SAAD, JUAN F.; VALIÑAS, MACARENA; HELBLING, WALTER

Global Change in Atlantic Coastal Patagonian Ecosystems: A Journey Through Time

Springer Cham

Año: 2022; p. 117 - 150

The coastal Atlantic area of Patagonia is a highly productive ecosystem, which sustains important commercial fisheries and constitutes a breeding ground of several flagship and charismatic species. It exhibits marked variability in physico-chemical and biological properties because it extends over a range of latitudes i.e., from temperate to subpolarenvironments; thus, it is a particularly interesting region to evaluate the effects of global change. Patagonia is already being affected by global change, as evidenced in historical patterns of diverse environmental drivers (e.g., temperature) as well as with important anthropogenic direct influences (i.e., sewage, industrial and agricultural wastes) in somesites. In this chapter we will focus on the effects of global change on plankton, but mostlyon phytoplankton, which constitute the base of this highly productive trophic web. The short-term impacts of global change on these organisms range from an inhibition of primary productivity, with solar ultraviolet radiation (UVR) being the dominant driver of this effect, to an enhancement mainly caused by increased inputs of nutrients. Indeed, most of the studies performed have evaluated the individual responses to solar UVR in bacterio-, phyto- and meroplankton, while a few others have assessed the spatial distribution of zooplankton in relation to anthropogenic influence. It is already known that when drivers of global change interact, they generally do so in an antagonistic or synergistic manner thus reducing orenhancing the individual effects. Some long-term effects of different combinations of global change drivers include taxonomic changes of the communities towards those dominated by potential mixo-/heterotrophic nanoflagellates, which may alter the atmosphere-sea exchangeand the potential sequestration of CO2 through the biological pump. The interaction of phytoplankton with heterotrophs (i.e., bacterio-, micro/mesozoo-, meroplankton) can affect the overall response to global change of plankton food webs mainly by cascading effects, butsurprisingly, very few experimental studies have considered trophic interactions between different biological organizational levels. Overall, the biased availability of data towards primary producers, and the lack of compelling data integrating different trophic levels complicate our understanding of plankton responses as a whole and thus, experiments that include multi-trophic levels are needed to improve our models and predictions on the impact of global change on coastal ecosystems of Patagonia.