The role of physical controls on phytoplankton community composition and carbon export in the Southern Ocean

Speaker: Meredith Meyer, University of East Anglia
Series: Quantitative Climate and Environmental Science Seminars

Due to its enhanced gas solubilisation and large, seasonal phytoplankton blooms, the Southern Ocean is a critical carbon sink, accounting for a substantial amount of total global carbon sequestration. However, due to anthropogenic climate change, it is also one of the fastest changing regions on the planet. Understanding how the Southern Ocean is evolving requires an understanding of how physical, chemical, and biological processes all interact and how individual changes will have cascading impacts through these complex systems. Of particular interest is how physical changes in sea ice cover, meltwater input, and mixed layer depth will impact bloom phenology and the concentration of key phytoplankton groups, such as diatoms, Phaeocystis antarctica, and cryptophytes, on the Antarctic continental shelf. Recent studies have shown that these physical controls impact phytoplankton type and distribution and have exhibited long-term changes over the last couple of decades. Furthermore, the balance between these three key, phytoplankton types has been shown to have a predictive relationship with the magnitude of carbon flux. Here, I will discuss what we know about physically-driven impacts on phytoplankton types and carbon export across different sectors of the Antarctic continental shelf, now and in the future.