Effects of ultraviolet radiation on Production and degradation of dissolved organic matter in the sea

对天然海水和人工海水进行了评价，研究了有色可溶性有机物（CDOM）作为溶解性有机物（DOM）的指标。还比较了过滤器类型，以获得无颗粒的过滤海水。养殖浮游植物在过滤后的天然海水中生长较好。Anodisc过滤器消除了海水中的大部分颗粒。几个浮游植物群进行了检查，硅藻生长以及细菌和CDOM增加，即使在过滤后的海水。在黑暗条件下，硅藻和细菌都不生长。但Anodisc过滤海水中没有细菌生长，因此没有产生CDOM。这一系列的实验结果表明，浮游植物产生CDOM，细菌利用这些CDOM。在紫外线辐射（UVR）和PAR的共同作用下，硅藻的生长速率比单独PAR的抑制。然而，每个细胞的CDOM的量与UVR高于一个没有UVR。综上所述，CDOM可以有效地应用于DOM动态研究，现有的培养方法可以用于评价DOM在海洋中的生态作用。

Natural and artificial seawater were evaluated to study on Chromophotic Dissolved Organic Matter (CDOM) as an index of Dissolved Organic Matter (DOM). Filter types were also compared to obtain particle-free filtered seawater. Cultural phytoplankton grew better in the filtered natural seawater. Anodisc filters eliminated most particles from seawater. Several phytoplankton group were examined and diatoms grew as well as bacteria and CDOM increased even in the filtered seawater. Under a dark condition, both diatoms and bacteria did not grow. But not bacteria grew in the Anodisc filter seawater and consequently no production of CDOM occurred. Those series of experiment may suggest that phytoplankton produce CDOM and bacteria utilize those CDOM. Under Ultraviolet Radiation (UVR) in addition to PAR, the growth rate of diatoms was depressed compared to PAR only. However the amounts of CDOM per cell were higher with UVR than one without UVR. In summary CDOM can be effectively employed to study dynamics of DOM, the present incubation methods can be applied to evaluate the ecological role of DOM in the ocean.