Distribution of methane in the water column of the Tropical seamount area (Atlantic Ocean)

Abstract

Studies of the temperature, salinity and methane concentration distribution by depth were carried out at a hydrological station in the area of a Tropical seamount (eastern part of the subtropical zone of the Atlantic Ocean) in the expedition “Complex studies of the Antarctic marine ecosys- tem in the nodal areas of the transport and interaction of water masses in the Atlantic sector of Antarctica, the Scotia Sea and the Drake Strait” onboard R/V “Akademik Mstislav Keldysh”, December 7, 2021 – April 5, 2022 (cruise 87).
When considering the temperature and salinity indicators, the main layers of the water column of this area were identified, and the values of methane dissolved in seawater were compared with the main hydrological indicators (temperature and salinity). It is shown that methane dissolved in seawater is concentrated under the pycnocline layer, and is also trans- ported in the barocline layer from a potential source in the Gulf of Guinea area to the north. In the area of a Tropical seamount, the methane concentration values correlate with the salinity values of seawater, which makes it possible to use the methane concentration indicator as an additional marker of various water masses in the ocean column, as well as to trace its source. In connection with the discussion of cooperation on oceanographic and coastal research in the Atlantic Ocean, the results of the article are important for the formation of a joint scientific agenda with the National Committee of Cape Verde within the framework of the United Na- tions Decade of Ocean Science, and are also part of the international obligations of the Russian Federation as a party to the Antarctic Treaty and the Convention on the Conservation of Marine Living Resources.
Research is becoming particularly relevant in accordance with the expected priorities of the GEOMIR project (ID 164, the head is R.B. Shakirov) United Nations Decade of Ocean Science for Sustainable Development (2021–2030).