Sciences marines : recherche et développement

Abstrait

A Study on the Bio-Limiting Nutrient Circulation in the Ocean’s Oxygen Minimum Zones

Grace A Abarike, Sibo Wang, Zhiguang Song

The ocean’s Oxygen Minimum Zone (OMZ) is known to be biogeochemical complex in terms of nutrient massbalance and major element cycles. The recent reports suggesting that the ocean’s OMZ facilitate about 25%-50% loss of nitrogen in the ocean predominantly by anammox coupled with the recent identification of the major contribution of DNRA to oceans NH₄⁺ flux, further complicates our understanding of the oceans nitrogen circulation and budget. Also, studies have shown that OMZ promotes the occurrence of sulfidic plumes. Moreover, the redox sensitivity of the ocean’s OMZ such as their active sulfate reduction and sulfide oxidation potential makes them important regions for the cycling of phosphorus. However, as have been predicted that future expansion and intensification of OMZ driven by climatic change, still the understanding of this biological system remains a challenge with regards to its role in the overall chemical budget of the ocean.

In this regard, we aim to provide a comprehensive summary of the overall circulation patterns of some essential but biologically limiting nutrients such as nitrogen, sulfur and phosphorus in this OMZ of the ocean. This will benefit future researches on predicting global budgets of these nutrients and their cycles related to the marine environment as it will help bring out a good understanding of the inextricable link among each of these limiting nutrients, as have been researched and reported in varied ways.