The Impact of Nitrogen and Phosphorus Dynamics on the Kinneret Phytoplankton: II: Chlorophyta, Cyanophyta, Diatoms and Peridinium

Abstract

Lake Kinneret long-term data of the epilimnetic concentrations (ppm) and loads (tones) of the total Nitrogen (TN), total Phosphorus (TP), total inorganic Nitrogen (TIN), total Dissolved Phosphorus (TDP), Phytoplankton groups' biomass, water level (WL) and Jordan River Discharge were analyzed. Previously collected data compiled aimed at an insight into the causative background for the modification of Phytoplankton community change. The study was carried out by searching for relations between algal groups' densities and nutrient conditions in the Epilimnion by the use of statistical methods (Simple and Fractional Polynomial Regressions). The study is aimed at analyzing the relations between algal biomass and nutrient contents. It was found that Nitrogen decline and slight increase of phosphorus were followed by Peridinium (Photo 1) decline and biomass increase of non-peridinium algae. It is suggested that nitrogen supply for algal growth is mostly from external sources, and the reduction of nitrogen in the epilimnion was caused by external removal. Contrary to nitrogen, phosphorus sourcing is only partly external (dust deposition, drainage basin) and mostly internal through double channels: Microbial mineralization of bottom sediments and Peridinium cysts mediation. The resulted complexity of the Kinneret ecosystem structure is nitrogen limitation, and enhancement of Non-peridinium algal growth, mostly Cyanobacteria.

Climate Change-Enhanced Cyanobacteria Domination in Lake Kinneret: A Retrospective Overview

“…This paper is a tentative confirmation of the impact of climate change on nutrient dynamics and consequent modification of Phytoplankton composition. Likely, climate changes of temperature increase and decline in rainfall and water discharges caused the decline of Peridinium and Cyanobacteria enhancement [25][26][27][28][29]. It is suggested that rainfall and river discharge decline caused the reduction of nitrogen supply [29].…”

Seasonal Water Level Fluctuation and Concomitant Change of Nutrients Shift Microeukaryotic Communities in a Shallow Lake

“…DOC, nitrogen, and phosphorus were important nutrient factors which could promote the growth of Ochrophyta [42]. In the wet season, module B, C, and E were dominated by Chlorophyta (Figures 3 and 8), which could be strongly driven by high temperature, high light, and high organic matter [43,92]. Like the overall microeukaryotic communities, most major modules in the dry season were closely correlated with nutrients, for example, high concentration of available nitrogen and SRP driven the growth of Cryptomonas and Ciliophora [33,93,94].…”