High rates of microbial carbon turnover in sediments in the deepest oceanic trench on Earth

Source: Nature Geoscience

Authors: Ronnie N. Glud, Frank Wenzhöfer, Mathias Middelboe, Kazumasa Oguri, Robert Turnewitsch,Donald E. Canfiel, Hiroshi Kitazato

Microbes control the decomposition of organic matter inmarine sediments. Decomposition, in turn, contributes to oceanic nutrient regeneration and influences the preservation of organic carbon¹.

Generally, rates of benthic decomposition decline with increasing water depth, although given the vast extent of the abyss, deep-sea sediments are quantitatively important for the global carbon cycle^{2, 3}. However, the deepest regions of the ocean have remained virtually unexplored⁴.

Here, we present observations of microbial activity in sediments at Challenger Deep in the Mariana Trench in the central west Pacific, which at almost 11,000 m depth represents the deepest oceanic site on Earth.

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