Author(s): B. Shteinman
Linked Author(s): Boris Shteinman
Keywords: Theoretical limnology; Hydrodynamics; Phytoplankton; Bloom; Modeling
Abstract: In spite of large amounts of theoretical and experimental work, a number of important aspects of the relationships between turbulence and patchiness have yet to be clarified. The aim of this contribution is to review some aspects of the relationships between water turbulence structure and patchiness formation, using Lake Kinneret as an example. The study was carried out via synchronous measurements of the turbulent fluctuations of the velocity and the fluctuations in chlorophyll a in vivo fluorescence (IVF). The relevant theoretical consideration for our purposes is Kolmogorov's theory of locally isotropic turbulence. The observed patterns of IVF act as water mass markers and, over certain scales, display the same eddy cascade structure as the water itself. Statistical processing of the raw data has shown that the cross-correlation function of turbulent fluctuations of the velocity and IVF fluctuations contains several peaks. The peak, corresponding to12 h is probably, produced by the phytoplanktons vertical migration generated by light availability and the accumulation of photoassimilates in the cells. The peak that appears at 5 h is linked with wind activity, and the peak at a time scale< 1 h is apparently due to turbulence. The linear dimensions of the patch also depend on the wind velocity, and on its direction.
Year: 2001