Manganese Cycling in the Subtoxic Zone in the Black Sea

OCE-0221500在黑海亚氧区的元素剖面表明，向上的硫化物通量可能是由锰氧化物而不是氧气氧化的，氨与硝酸盐反应生成氮气。此外，剖面图表明，Mn(II)氧化发生在厌氧条件下，可能与反硝化作用相耦合。然而，提议的反应的发生仍然存在争议。斯克里普斯海洋研究所的一名科学家与来自华盛顿大学、特拉华大学、蒙特利湾水族馆研究所、俄罗斯和乌克兰的科学家合作，计划在黑海亚氧区进行实地工作，并进行实验室培养实验，以检验锰物种是硫化物和氨的氧化以及硝酸盐和亚硝酸盐还原的催化剂这一假设。PI还将评估氧化锰(II)和还原锰(III、IV)的微生物和非生物反应速率，并评估氧气如何影响这些过程。在实验室中，还将确定细菌的分布和参与黑海垂直和水平横断面的锰(II)氧化的基因。最后，PI将确定横向投入与现场过程在控制黑海次氧区方面的重要性。

OCE-0221500Elemental profiles in the suboxic zone of the Black Sea suggest that the upward flux of sulfide may be oxidized by manganese oxides rather than oxygen and that ammonia reacts with nitrate to produce N2. In addition, the profiles suggest that Mn(II) oxidation occurs anaerobically, possibly coupled to denitrification. However, the occurrence of the proposed reactions remains controversial. A scientist from Scripps Institute of Oceanography, in collaboration with scientists from the University of Washington, the University of Delaware, Monterey Bay Aquarium Research Institute, Russia and Ukraine, plans to carry out field work in the suboxic zone of the Black Sea, as well as laboratory culture experiments to test the hypothesis that Mn species act as a catalyst for oxidation of sulfide and ammonia and reduction of nitrate and nitrite. The PI also will assess the microbial and abiogenic reaction rates of the oxidation of Mn (II) and reduction of Mn (III, IV) and assess how oxygen affects these processes. In the laboratory, the distribution of bacteria and the genes involved in Mn(II) oxidation throughout the vertical and horizontal transects of the Black Sea also will be determined. Lastly, the PI will ascertain the importance of lateral inputs versus in-situ processes in controlling the suboxic zone of the Black Sea.