Insights into eukaryotic phytoplankton and CO2 uptake in the marine biosphere

Abstract:

Approximately half of global photosynthetic fixation of CO₂ occurs in the marine biosphere. Development of more predictive mechanistic carbon cycle models is currently limited by the lack of understanding of physiological growth controls and quantitative information on the forces of mortality that act on the phytoplankton responsible for this CO₂ uptake. A complication for research in this area is the fact that phytoplankton are exceptionally diverse. Primary productivity is not only partitioned between cyanobacterial and eukaryotic phytoplankton, but groups within the latter also have very different evolutionary histories and only some are represented in culture. Here, we will explore the advances and challenges in studying eukaryotic phytoplankton and factors that limit their growth in nature. Specifically, we will discuss ecosystems biology approaches that involve iteration between the lab and field and are proving most successful for gaining insight to environmental parameters that structure phytoplankton communities and growth.