Female krill gather at hydrothermal vents
A surprising discovery is changing our understanding of the life of Antarctic krill. Researchers have found sexually active females at hydrothermal vents at depths of more than 1,000 metres. There, the animals appear to be utilising an unusual food source.
Antarctic krill (Euphausia superba) is one of the most important species in the Southern Ocean. Whales, penguins, seals and numerous fish depend on these small crustaceans. Until now, research has focused primarily on the upper water layers.
An international research team led by Kim Bernard of Oregon State University has now discovered krill at a depth of around 1,100 metres on the Hook Ridge in the Bransfield Strait, between the Antarctic Peninsula and the South Shetland Islands. Using the ROV SuBastian, four krill were recovered, all of which were sexually mature, already mated females.
Underwater imagery from the Quest Caldera in the Scotia Arc also revealed large concentrations of krill around hydrothermal vents. Analyses of the gut microbiome, isotopes and trace elements suggest that the krill feed on chemosynthetic microorganisms there. These derive their energy from chemical compounds in the deep-sea vents and do not require sunlight.
It is still unclear why reproductive-age females in particular seek out these habitats. The researchers suspect that the hydrothermal vents provide a reliable food source and possibly important trace elements for reproduction.
The discovery could also be significant for the conservation of Antarctic krill. If hydrothermal vents are regularly used by females during reproduction, these deep-sea areas – which have received little attention to date – would represent important habitats.
The findings were published by the team led by Kim S. Bernard of Oregon State University on 15 September 2026 in the journal Communications Biology under the title ‘Deep Sea hydrothermal vent habitats support gravid Antarctic krill’.
Heiner Kubny, PolarJournal
