The Productivity of Polar Marine Systems and Their Response to Global Change
2014 GC Seed Grant
High latitude oceans are major contributors to global primary production with the Southern Ocean alone accounting for around 20% of annual global phytoplankton production. A large proportion of this production is confined to continental shelf regions such as the Western Antarctic Peninsula (WAP), where intense phytoplankton blooms common in the spring produces proportionally greater phytoplankton biomass compared to lower latitudes. This provides the basis for short but substantive food webs and results in a high degree of CO2 sequestration.
There is a need to better understand the mechanisms responsible for phytoplankton bloom in high latitude oceans and how the resulting productivity will be affected by global change. The dynamic, seasonal variation in phytoplankton productivity at these latitudes is currently a major limitation in Earth System Models. Furthermore, high latitude oceans, and specifically the WAP, are experiencing some of the most extreme warming on the planet and the low buffering capacity of high latitude seawater will result in a particularly large response to rising anthropogenic CO2. Research to date has focused on determining the effects of rising temperature on the magnitude of the spring bloom, but there is limited understanding on the mechanisms that control the rates of carbon fixation and consumption in high latitude marine ecosystems.
Through this project, Morel and his team plan to address three main questions: What mechanisms allow low respiration rates in phytoplankton at low temperatures? How does the balance of photosynthesis, respiration and cellular composition vary over diurnal cycles? How does the balance of photosynthesis, respiration and cellular composition change with temperature?
Many of the experiments will be conducted with participation of undergraduate students. For example, undergraduates in Morel’s laboratory have successfully grown and carried out experiments with model phytoplankton species, including measurements of carbon fixation and respiration rates, as well as quantification of proteins and their turnover rates. The team is focused on involving as many students as space allows in the lab to conduct research and to providing a high-quality research experience.
Over the past four years, Morel and his team focused on integrating integrate research, teaching and mentoring activities according to the original vision of the Grand Challenge initiative of PEI. One element has consisted of introducing their current research topics into coursework with the objective of providing a sense of “live science” in their undergraduate teaching. The proposed work on polar marine systems and global change provides excellent examples of applications of topics covered in their undergraduate courses and this work will also be introduced in: