The phase transition of ecosystem structure in the upper ocean

(1)测定了亚北极太平洋地区细菌丰度、产量、外酶活性（氨基肽酶和β -葡萄糖苷酶）以及氨基酸浓度的垂直和水平分布。这些微生物参数呈现出明显的东西梯度，总体上西高东低。研究结果表明，研究区生态系统结构发生了大规模的变化，这可能与浮游生物群落结构和生物地球化学变化有关。(2)为探讨海洋环境中有机物-细菌系统的调节机制，采用放射性示踪技术测定了高分子碳水化合物的分解速率。结果表明，有机质络合作用对海洋系统中有机质的保存起着重要作用。(3)利用海洋生物地球化学数据库参数模拟了海洋环境中有机质-微生物动力学。分析表明，由于海洋生态系统内有机物的密集循环，网络虚拟放大在海洋生态系统中很常见。

(1) Vertical and horizontal distributions of bacterial abundance, production and ectoenzyme activities (amino peptidase and beta-glucosidase), as well as amino acid concentrations were determined in the subarctic Pacific. These microbial parameters exhibited notable east-west gradient, with generally high values in the west and low values in the east. The data suggest a large-scale regime shift of ecosystem structure in the investigated region, which appeared to be related to plankton community structure and biogeochemical variations.(2) In order to examine regulation mechanisms of organic matter - bacteria systems in marine environments, decomposition rates of polymeric carbohydrate was determined by using radio tracer techniques. Results suggest that organic matter complexation plays an important role in preservation of organic matter in marine systems.(3) Organic matter-microbial dyanamics in oceanic environments was modeled by using parameters derived from a oceanic biogeochemical data base. The analysis revealed that network virtual amplification is common in oceanic ecosystems because of intensive recylcing of organic matter withing the system.