Physical and biological controls on the spatial distribution of phytoplankton in a large lake

Phytoplankton spatial heterogeneity, a ubiquitous feature in both oceans and lakes, has been studied for decades as the patterns observed often gives insights into the underlying controlling mechanisms. Constraints in the advancement of this research subject, due to the lack of spatial coverage using conventional in-situ point sampling methods, have been overcome in recent years with the development of remote sensing technology. The theme of this thesis is to investigate the physical and biological processes responsible for the spatial patterns of phytoplankton through the application of remote sensing information, in-situ measurements, numerical and analytical modelling, and geo-statistical approaches, for Lake Kinneret (Israel). The first part of this research examined the role of physical processes, more specifically, internal waves and wind, on the phytoplankton horizontal distribution during a dinoflagellate blooming season using a set of satellite images of chlorophyll a. It was found that phytoplankton concentration emerged as narrow bands in the northern region of the lake typically remained adjacent to the shoreline at the start of the bloom, but progressively propagated away from the shoreline towards the centre of the lake as the bloom proceeded. The application of a three-dimensional (3D) hydrodynamic numerical model and an analytical model for flatbottomed elliptical basins together attributed the observed phenomenon to the change in structure of internal waves as well as wind.