Abstract

During the first national study of the oxygen minimum zone (OMZ) and the animal macrobenthos off northern Chile (1962), a benthic community mainly composed of giant filamentous multicellular bacteria was discovered in the highly reduced shelf bottoms between 50-182 m depth. Totally unexpected were the great abundance of massive and visible filamentous bacteria and the pronounced scarcity of macrobenthic animals. More recently (2004) a new assemblage of smaller filamentous multicellular bacteria was again discovered interspersed within the more reduced subsurface sediment of the same bacterial mat. Today we recognize that this prokaryote-dominated ecosystem constitutes a major distinct benthic marine feature and thus it is here named "Humboldt Sulfuretum" (HS) for his distribution under the OMZ between central Peru and central Chile. During a period of intense scientific research which took off after 1977, strongly based on international collaboration, a large body of information fundamental to the understanding of the Humboldt Current Large Marine Ecosystem has accumulated on the first assemblage and its environment while the research on the second assemblage is just beginning. The present work is an effort to put together most of the pertinent literature with the intention of stimulating local researchers to face the much urgent, major scientific effort along the many lines offered by the biota and the environment of the Humboldt Sulfuretum.