ABSTRACT
Although the Challenger expedition documented reduced oxygen in what are now recognised as OMZs (Ditmar 1884), detailed exploration of OMZ biology is relatively new. The Meteor Expedition reported collecting bottom samples with high sulphur content from the shelf near Walvis Bay and attributed these to decomposing wastes of whale processing (Spiess 1928). The discovery of depleted faunas in the Arabian Sea OMZ occurred aboard the RV MABAHISS during the Murray Expedition of 1933-4, but these results were not published and a full understanding of the oxygen minimum layer in this region did not occur until the International Indian Ocean Expedition of 1959-65 (Gage et al. 2000). This was the same period in which Wyrtki published details of anoxia in the world ocean (Wyrtki 1962) and in the eastern Pacific (Wyrtki 1966). Serious deep-water biological studies of OMZ effects on benthic communities began with Sanders’ (1969) landmark transect off Walvis Bay. The first benthic studies within the eastern Pacific OMZ took place in the 1960s off northern Chile (Gallardo 1963) and Peru (Frankenberg & Menzies 1968, Rowe 1971).
