Physical Processes with Biology

Living marine organisms have spent most of their evolutionary time history as single cells, at scales dominated by viscous force. As life evolved toward a larger and more mobile multicelled organism, inertial forces also became important. Hence, microscale organisms in the ocean have experienced small-scale fluid motions throughout their entire existence on Earth. In this chapter we consider how microscale organisms interact with small-scale physics in the ocean, based on current knowledge. We focus our attention on how the behavior of planktonic organisms might be affected by the immediate flow field; hence, we target the behavior of individual motile plankton. The dynamics of the upper ocean are complex, not the least because of air–sea interaction processes. Winds cause various physical processes, which are not mutually independent: waves, currents, turbulence, and coherent flow structures such as