Evolutionary processes in calcifying organisms under future warming and biogeochemical implications

ended

Future global warming will impact diverse marine ecosystems. Marine calcifiers play important roles as ecosystem engineers and in the carbon cycle. Two major groups of calcifying organisms are coccolithophores and Large Benthic Foraminifera (LBF). Coccolithophores are considered to be the most prominent carbonate producer in the ocean and also contribute about 50% of global primary production. LBF are major calcifiers in reef and other shallow marine environments. This group is usually characterised by algal symbiosis, making them contributors to primary production in tropical to subtropical areas. Understanding the response of these organisms is imperative as their ability to calcify and photosynthesis have major biogeochemical implications. An important mechanism that allows organisms to cope with rapid climate or local environmental changes is physiological plasticity both within ontogenetic development and across generations. Transgenerational plasticity is specifically relevant when trying to understand the possible impacts of climate change since these anthropogenic changes will persist across generations. Hence, one of the main challenges of studying future effects on organisms is evaluating their adaptation potential through short laboratory experiments. To overcome this challenge, we will conduct multigenerational laboratory experiments simulating adaptation under future warming scenarios and estimate predicted changes in calcification and photosynthesis. Then, we will investigate carbonate shells from warm intervals in the geological record as a field experiment of extreme warmth under natural conditions. This will validate or highlight the gaps between experimental results and adaptation under natural conditions. Our results will indicate how adaptation will mitigate the response of coccolithophores and LBF to ocean warming and provide a realistic prediction of the biological effect of the organic pump versus the carbonate counter pump on oceanic pCO2.