Dr. Christian Lindemann Department of Biological Sciences (BIO), University of Bergen, Norway
Phytoplankton is central to our understanding of nutrient cycling, carbon export and in the marine ecosystem as a whole. During winter in the North Atlantic overturn of deep convection has been suggested to play a critical role in phytoplankton survival, with both, biological and physical controls, being important. Turbulent flow velocities influence phytoplankton growth and biomass aggregation and can sustain cell within the water column. The cells ability to modify respiratory and sinking rates in response to changes in the external environment mediates phytoplankton dynamics and can help to explain the observed phytoplankton biomass.
Similarly, such adaptive capacities can control nutrient uptake, thus modulating nutrient cycling. However the commonly used empirical application of the Michaelis-Menten equation ignores the multiple underlying feedbacks between physiology and nutrient uptake, thus leading to fundamental shortcomings in the interpretation of relationships describing nutrient uptake in microbes. By combining the effects of growth, cell size, elemental stoichiometry and cell motion with the theory of diffusion, these limitation can be addressed.
Understanding these adaptive qualities has important implications for the accurate representation and predictive capabilities of model applications, in particular in a changing environment