Light, iron and carbon dioxide availability as potential modulators of phytoplankton community dynamics in Ryder Bay, Western Antarctic Peninsula

Climate models indicate that the Southern Ocean is particularly prone to climate change, with important implications for Southern Ocean phytoplankton ecology. Next to the ongoing OA, CO2 as a green house gas has already caused global average temperatures to increase by 0.6 °C over the past 100 years. The Western Antarctic Peninsula has been reported to be one among the most rapidly warming regions of the Southern Ocean, with a 2 °C increase in the annual mean temperatures since 1950. The strong warming and freshening of Antarctic surface waters will enhance vertical stratification and reduce mixed-layer depth, which in turn will elevate mean irradiances phytoplankton cells encounter. Increased stratification is expected to also reduce vertical nutrient and trace element fluxes. These physico-chemical changes will not occur independently from each other and their interactive effects will inevitably affect coastal phytoplankton communities. To better understand the impact of light, iron and carbon dioxide availability as potential modulators of phytoplankton community dynamics in Ryder Bay (Rothera research station), we conducted incubation experiments with the in-situ phytoplankton assemblage in February 2015. This project was conducted in cooperation with Dr. Elizabeth Jones, Mairi Fenton and Prof. Hein de Baar from the NIOZ.