Bioluminescence and Plankton Communities in the Atlantic Sector of the Southern Ocean

Vertical bathyphotometric casts of the bioluminescent potential by the Salpa MA+ probe was carried out from January through February 2022 at 37 stations in the photic layer in the Bransfield Strait, the Antarctic Strait and the northwestern part of the Weddell Sea during the 87th Antarctic Expedition of the research vessel “Academician Mstislav Keldysh”. Vertical casts were accompanied by measurements of temperature, electrical conductivity, photosynthetically active radiation and collection of plankton samples with their subsequent processing. 7 bioluminescent plankton species have been identified, namely: Pelagobia longicirrata Greeff, 1879, Protoperidinium depressum (J.W. Bailey) Balech, 1974, Protoperidinium antharcticum, Metridia gerlachei Giesbrecht, 1902, Oithona similis Claus, 1866, Euphausia superba Dana, 1850 and Salpa thompsoni Foxton, 1961. Comprehensive studies have shown that the spatial structure of the bioluminescent potential field (its vertical and horizontal components) is formed by two main factors: the taxonomic structure of the plankton community and the thermohaline structure of the biotope. The species and taxonomic groups dominating the formation of bioluminescent potential differed significantly in all three research areas. The characteristics of the thermohaline structure in them were significantly different as well.