Influence of nutrients, submerged macrophytes and zooplankton grazing on phytoplankton biomass and diversity along a latitudinal gradient in Europe

Abstract

In order to evaluate latitudinal differences in the relationship of phytoplankton biomass and diversity with environmental conditions in shallow lakes, we sampled 98 shallow lakes from three European regions: Denmark (DK), Belgium/The Netherlands (BNL) and southern Spain (SP). Phytoplankton biomass increased with total phosphorus (TP) concentrations and decreased with submerged macrophyte cover across the three regions. Generic richness was significantly negatively related to submerged macrophyte cover and related environmental variables. Zooplankton:phytoplankton biomass ratios were positively related to submerged macrophyte cover and negatively to phytoplankton generic richness in DK and BNL, suggesting that the low generic richness in lakes with submerged macrophytes was due to a higher zooplankton grazing pressure in these regions. In SP, phytoplankton generic richness was not influenced by zooplankton grazing pressure but related to conductivity. We observed no relationship between phytoplankton generic richness and TP concentration in any of the three regions. The three regions differed significantly with respect to mean local and regional generic richness, with BNL being more diverse than the other two regions. Our observations suggest that phytoplankton diversity in European shallow lakes is influenced by submerged macrophyte cover indirectly by modulating zooplankton grazing. This influence of submerged macrophytes and zooplankton grazing on phytoplankton diversity decreases from north to south.

A Preliminary Study on Phytoplankton in Fresh Water-Lake of Gogi, Yadgir District, Karnataka

“…Similar observations were made by Kanagasabapathi and Rajan [1]. There are several studies that discuss the effects of environmental, physico-chemical factors on phytoplankton [6,7,17]; an osmotic stress also causes a decline in phytoplankton diversity in the lake ecosystem [26]. However the effects of various factors on the seasonal appearance and disappearance of phytoplankton differ significantly across the Lake ecosystem [19].…”

Long-Term Trends and Temporal Synchrony in Plankton Richness, Diversity and Biomass Driven by Re-Oligotrophication and Climate across 17 Danish Lakes

“…This was probably indicative of water quality improvements, which might have promoted submerged macrophyte growth. The potential recovery of submerged macrophytes may also contributed to the increase in planktonic diversity [82][83][84][85].…”

Effect of removal of free-floating macrophytes on zooplankton habitat in shallow wetland

“…Zooplankton (mainly rotifers and cladocerans) utilize macrophytes efficiently. Complexly structured macrophytes, such as submerged macrophytes, enhance the opportunities that zooplankton have for avoiding predators, and the surfaces of their stems and leaves are important attachment sites for epiphytic zooplankton (Stansfield et al, 1997;Muylaert et al, 2010), creating a complex habitat that makes a large contribution to zooplankton assemblages (Meerhoff et al, 2007). However, some reports have claimed that submerged macrophytes were mainly used by pelagic zooplankton, such as daphnids, as their daytime refuge (Lauridsen and Lodge, 1996;Burk et al, 2002), and that a large number of zooplankton species often inhabit floating-leaved or free-floating macrophytes.…”