Biodiversity alteration of planktonic calcifiers

Marine biodiversity changes of animals, plants, and microbes are clearly one of the greatest threats today to the world’s largest ecosystem, the surface ocean, in terms of the great variety of ecosystem services that it provides to humankind. This is due to unprecedentedly fast rates of climate change under anthropogenic pressure that are warming the oceans, reducing stratification, causing deoxygenation and ocean acidification, and more, with largely unknown consequences from plankton to fisheries, despite the strong dependence both traditional and modern society have on the oceans, for basic protein food supply, and so much more. Fish overharvesting alone is implicated in reduced ecosystem complexity, changes in size spectrums of plankton that determine trophic organization, metabolic activities, organic matter export, and more. Most knowledge on marine biodiversity loss however comes from larger nekton and macro-species, with far less known from micro-organisms at the base of many marine food webs, such as planktonic calcifying organisms of coccolithophores, foraminifera, and pteropods, as both phyto- and zoo-plankton forms that routinely become fossilized in the sedimentary record due to their CaCO3 test mineral structure.

BIOCAL focuses on these 3 planktonic calcifier groups exclusively, with modern assessments of climate change impacts to water column counts and biodiversity patterns across major globally relevant working areas as the N. Pacific, Southern Ocean, and Mediterranean Sea, as well as a new oceanographic expedition in the N. Atlantic, each characterized by strong gradients in biogeochemical properties across oceanic frontal systems. We will also calculate the carbonate contribution based on these assessments, to better constrain the marine carbon cycle. Further, we will calculate biodiversity change rates from the sedimentary records of the same groups over key past timeframes, involving the pre- versus post-Industrial era, and the last deglaciation, to better frame the biodiversity change rates of modern times against important context.

The BIOCAL findings are expected to provide critical new knowledge on marine biodiversity change rates from the perspective of the 3 main planktonic calcifying groups, with major implications for surface ocean ecology, food webs, fisheries, and more. Furthermore, BIOCAL will incorporate 2 PhD students that will engage actively throughout the project, collaborating with outstanding experts internationally across Europe as part of the excellent team. BIOCAL will ultimately yield high-impact findings publishable in the highest-ranking scientific journals and literature outlets. BIOCAL will promote public outreach efforts and thereby foment broader public interest and engagement. We further expect the BIOCAL project to affect policy changes at international and regional levels with a set of best practice guidelines developed on the basis of the results as well.