Methane migration, sea ice melting and spatial distribution of chlorophyll-a in the Barents Sea

The paper considers the theoretical and practical aspects of the relationship between the processes of sea ice melting and methane migration, and their influence on the distribution of chlorophyll-a concentration as an indicator of productivity and the level of quantitative development of the phytoplankton community at the spring stage of the succession cycle. In the spring of 2018 and 2019 the thermohaline characteristics of waters and the content of chlorophyll-a in the Barents Sea were studied. The area of work covered both areas with the most probable release of methane from near-bottom gas hydrates, as well as background areas, where the presence of methane hydrates is unlikely. In 2018, the phytoplankton community of the study area was in the spring flowering stage. In the area of the most probable influence of methane, the average concentrations of chlorophyll-a were approximately 2 times higher than in the background area. High concentrations of the pigment were associated with the thawed layer, which may indicate the release of methane from the ice. In 2019, low concentrations of chlorophyll-a in the edge zone excluded the stage of spring flowering of the phytoplankton community, which did not allow us to trace the possible effect of the release of methane hydrates on the concentration of chlorophyll-a.