The Southern Ocean is one of the most productive marine ecosystems in the world and is serving as feeding grounds for a multitude of seabirds and marine mammals. Especially the humpback whale and the southern right whale depend on the region to feed on krill before embarking on long fasting periods while calving at lower latitudes.
The toxic diatom genus Pseudo-nitzschia is among the most frequently encountered and dominant diatom genera in Antarctic waters, e.g. contributing 13-70% of diatom densities in the Weddell Sea. Pseudo-nitzschia is a known producer of theneurotoxin domoic acid (DA) in temperate and tropical waters, causing amnesic shellfish poisoning in humans. DA accumulates in a wide range of pelagic and benthic organisms across the marine food web, like krill, copepods, fish, and bivalves. Marine mammals that feed on DA-contaminated prey are at the risk of suffering acute and chronic poisoning with effects like reduced reproduction, seizures, and death.