Genome size affects phytoplankton response to environmental factors: A preliminary exploration in 26 lakes in the region east of the Hu Huanyong Line

Given their varied physiological and ecological attributes, phytoplankton frequently exhibit disparate responses to changes in environmental conditions. Therefore, when studying modifications in the structure of a phytoplankton community, it is necessary to consider such differences and investigate the underlying mechanisms. Through a field sampling study of 26 lakes, we found that the differing responses of phytoplankton to changes in environmental factors were partly related to their genome size. The Cyanobacteria and Chrysophyta, which possess smaller genomes, exhibited a relatively low degree of sensitivity to alterations in nutrient concentrations. However, they demonstrated a stronger dependence on the metabolic processes of environmental microorganisms compared to other phytoplankton with larger genomes. Furthermore, the Cyanobacteria and Chrysophyta were more closely associated with environmental nutrients and water chemistry and were more actively involved in interspecific interactions among phytoplankton. By randomly deleting sample points, we verified the generality of the above conclusions. However, more refined grouping analyses indicate that diatoms exhibited different ecological characteristics due to their physiological and morphology. The present study offers new insights into the mechanisms underlying the ecological adaptations of phytoplankton and may provide new guidance for the management of Cyanobacterial blooms. Further studies could take a more refined approach to investigate the effect of phytoplankton “effective genome size” on their adaptive capacity.