Reactive Trace Chemicals in Ocean Surface Waters: Hydrogen Peroxide, Manganese and Gallium

铁等活性痕量物种对表层海洋化学和生物生产力有重要影响。然而，其他可能影响初级生产、影响其他元素的化学分布或可用作示踪剂的痕量物种受到的关注较少。为此，南密西西比大学的两名PI将参加第四次国际奥委会巡航西北太平洋，以测定地表水、垂直剖面、雨样、尘埃溶解实验和/或孵化实验中的锰、过氧化氢和镓。对过氧化氢的测定将用于以下方面：(1)将测量添加到一个不断增长的数据集，目的是检查地表水中粉尘的光化学溶解；(2)确定它是否有助于表层海洋中颗粒铁的溶解；以及(3)评估光产生和暗衰变的速度。锰的值将与铝和镓进行比较，以区分粉尘和货架输入的粉尘。此外，鉴于锰在表层海洋中的停留时间较长，PI将尝试使用这种金属来为上层海洋的铁输入提供新的见解。将锰与H_2O_2进行比较，可使PI测定锰氧化物在海水中的还原溶解。最后，将把镓的浓度与铝的浓度进行比较，以评估前者是否可能不是向表层海洋输入尘埃的更好的替代物，确定是否有任何组分是人为的，以及是否有任何镓与有机物络合，产生可能的镓-铁竞争相互作用。

ABSTRACTOCE-0137359Reactive trace species such as Fe have an important effect on surface ocean chemistry and biological productivity. However, other trace species that can influence primary production, affect the chemical distribution of other elements or can be used as tracers have received less attention. For this reason, two PIs from the University of Southern Mississippi will participate in the 4th IOC cruise to the Northwest Pacific to determine Mn, H2O2 and Ga in surface waters, vertical profiles, rain samples, dust dissolution experiments and/or incubation experiments. Determinations of H2O2 will be used for the following: (1) add measurements to a growing dataset aimed at examining photochemical dissolution of dust in surface waters; (2) determine whether it aids in the solubilization of particulate Fe in the surface ocean; and (3) assess rates of photo-production and dark decay. Values for Mn will be compared with Al and Ga to differentiate dust from shelf inputs. In addition, given the longer residence time for Mn in the surface ocean, the PI will attempt to use this metal to provide new insights into Fe inputs to the upper ocean. Comparison of Mn with H2O2 will allow the PIs to determine reductive dissolution of manganese oxides in seawater. Lastly, Ga concentrations will be compared with Al to assess if the former may not be a better proxy for dust inputs to the surface ocean, determine if any fraction is anthropogenic and whether any of the Ga is complexed with organics creating possible Ga-Fe competitive interactions.