Rates of organic matter transformation within the production-destruction cycle of the White Sea

Rates of organic matter (OM) transformation within the production-destruction cycle of the White Sea were estimated on the basis of measured activity values of redox enzymes of the electron transport system and of hydrolytic enzymes (phosphatase and protease). It was found that OM oxidation processes were the most intensive in the Kandalaksha Bay, while minimum oxidation rates were characteristic of central parts of the Dvina and Onega bays. It was revealed that the highest rates of phosphate mineralization were characteristic of the central part of the sea and near-mouth areas of the Onega and Kandalaksha bays, with the lowest rates in the Dvina Bay. During the period of intense primary production when resources of inorganic phosphorus were practically depleted, high rates of phosphate regeneration were observed. It was shown that populations of micro- and zooplankton in the White Sea were characterized by low activation energies of the principal metabolism reactions (3-6 kcal/mol), which allowed these populations to provide exchange intensity comparable to that of inhabitants of warm waters during all the seasons.基于电子传递系统（electron transport system）的氧化还原酶（redox enzymes）与水解酶（hydrolytic enzymes，包含磷酸酶phosphatase和蛋白酶protease）的活性测定结果，本研究估算了白海有机质（organic matter, OM）生产-降解循环中的转化速率。研究发现，有机质氧化过程在坎达拉克沙湾（Kandalaksha Bay）最为强烈，而德维纳湾与奥涅加湾的中部区域则呈现最低氧化速率。研究显示，磷酸盐矿化的最高速率出现在白海中部以及奥涅加湾与坎达拉克沙湾的河口附近区域，德维纳湾的矿化速率最低。在初级生产旺盛、无机磷资源几近耗尽的时期，观测到较高的磷酸盐再生速率。研究表明，白海的微型浮游动物与浮游动物种群的主要代谢反应具有较低的活化能（3~6 kcal/mol），这使得这些种群在全年各季节均可达到与温水水域生物相当的物质交换强度。