Factors maintaining the identity of mesoplankton communities: cool evidence from the Drake Passage

摘要

The Southern Ocean is a crucial component of the global climate system and plankton communities inhabiting the Ocean are important in the global carbon cycle. Our paper is aimed to reveal possible factors, which keep identity and explain changes of the community structure at the mesoscale. We tested the absolute values of environmental variables (e.g., temperature, salinity, chlorophyll) as well as the position of the oceanic frontal zones and water masses as these possible factors. We chose the epipelagic zone of the Drake Passage as a unique environment, where gradients of abiotic variables are the most sharp and the boundaries between water masses are not always coincident with the position of fronts: we recorded six water masses and two hydrological fronts. No strict connection between the position of hydrological fronts and absolute values of hydrological variables from one side, and community variables from another, was found. Instead, boundaries between communities coincided with the boundaries between water masses thus indicating greater importance of water mass origin and history and lesser importance of the current hydrological variables.