We analyzed the potential activity of β-glucosidase , leucine-aminopeptidase , alkaline phosphatase and chitinase EEA, together with prokaryotic abundance and 3H-leucine incorporation in the water column (from surface to 4,000 m) in 10 Longhurst biogeographical provinces of the Atlantic, Pacific and Indian Oceans during the Malaspina 2010 Circumnavigation Expedition. In the global ocean the prokaryotic abundance and leucine incorporation decreased 2 and 3 orders respectively from surface to deep waters, while EEA only decreased 50 %, and hence EEA on a cell basis significantly increased with depth. In most of the provinces there was a close relationship between the level of EEA in surface and deep waters. These results suggest that a significant fraction of the enzymes released at the surface of the ocean may be transported to the deep layers, where they can remain stable and active. Moreover, in most of the Longhurst provinces, EEA (mainly leucine-aminopeptidase) and leucine incorporation were linked processes in surface but not in deeper waters, which suggest that the hydrolysis of high molecular weight substrates is a rate-limiting step of prokaryotic growth only at surface

Aquatic Sciences Meeting, Aquatic Sciences: Global And Regional Perspectives - North Meets South, 22-27 February 2015, Granada, Spain

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