Collaborative Research: Photochemical and Optical Properties of Antarctic Waters in Response to Changing UV-B Fluxes

【摘要】南极水域对UV-B通量变化的光化学和光学性质响应南极上空平流层臭氧的减少导致了高光区UV-B通量的增加。这种增加导致水生生物的细胞损伤，如光抑制和生产力下降所证明的那样。细胞损伤既可以发生在细胞内，也可以发生在细胞表面的外部生物分子反应，这些反应是由外部产生的反应瞬态引起的。这种细胞外损伤的程度取决于细胞周围海水的光化学性质。直到最近，人们对南极水域中瞬时光化学过程的类型、速率和稳定状态浓度一无所知。建议进行实地实验，以建立表面水和深度的光化学生产速率预测模型。这些研究将包括进一步的量子产率测量，开发一个敏感的水下光度计系统，以及使用一个新的水下多通道光度计。该模型将允许预测不同水平的UV-B对上层水柱中几种关键反应瞬态物种的光合作用和稳态浓度的影响。除了这项工作之外，还将进行实验，研究溶解有机物的光降解，并确定光化学形成的生物可利用的底物是否能提高南极水域的次生生产力。

ABSTRACT K. Mopper & D. Kieber OPP 9527255 & OPP 9527314 PHOTOCHEMICAL AND OPTICAL PROPERTIES OF ANTARCTIC WATERS IN RESPONSE TO CHANGING UV-B FLUXES The decrease in stratospheric ozone over the Antarctic results in an increase in the UV-B flux in the euphotic zone. The increase leads to cellular damage to aquatic organisms, as documented by photo-inhibition and decreased productivity. Cellular damage can occur either intracellularly, or externally at the cell surface from biomolecular reactions with externally-generated reactive transients. The extent of this extracellular damage will depend on the photochemistry of the seawater surrounding the cell. Until recently, nothing was known about the type of photochemical processes, rates, and steady state concentrations of transients in Antarctic waters. It is proposed that field experiments be performed which will allow the construction of predictive models of photochemical production rates in surface waters and with depth. These studies will involve further quantum yield measurementts, development of a sensitive underwater actinometer system, and use of a new underwater multichannel photometer. The model will allow the prediction of the impact of varying levels of UV-B on the photoproduction and steady state concentration of several key reactive transient species in the upper water column. In addition to this effort, experiments will also be performed to study the photodegradation of dissolved organic matter and to determine whether biologically utilizable substrates that are formed photochemically can enhance secondary productivity in Antarctic waters.