Modeled inherent scattering properties of small light-limited phytoplankton: Implications for deep phytoplankton size class distributions

Small phytoplankton (<2μm), ubiquitous throughout the world's oceans, numerically dominate many open ocean ecosystems with increasing importance towards the base of the euphotic zone. As an example, light-limited deep secondary chlorophyll maxima are usually dominated by small phytoplankton species. Theoretical models describing light-particle interactions predict that small particles scatter light less efficiently than their larger counterparts. To investigate a possible relationship between the dominance of small phytoplankton in light-limited situations and efficiency predictions, a light scattering efficiency model based on Mie theory as approximated by Van de Hulst is used to determine scattering efficiency as a function of size. This scattering efficiency model, which approximates light-phytoplankton interactions by considering phytoplankton as homogeneous spheres, is driven by the spectral light field from an observed deep (∼135m) phytoplankton population dominated by small phytoplankton. This deep secondary chlorophyll maximum is discussed as an example of a highly efficient small phytoplankton population at the threshold of the euphotic zone which could benefit as a result of its size distribution. ©2005 Copyright SPIE - The International Society for Optical Engineering.

Duke Scholars

Author Zackary Johnson Marine Science and Conservation