长江口邻近海域不同来源营养盐对初级生产的作用

The sea areas adjacent to the Yangtze River Estuary have a complex habitat, and biological disasters such as red tides occur frequently, which are closely related to the supply of nutrients. Rivers and the ocean bring a large amount of nutrients to the sea areas adjacent to the Yangtze River Estuary. However, there are still many uncertainties about the relative importance of nutrients from different sources for primary production in this sea area. In this paper, a Physical-Biological Coupling Module combined with a Nutrient Tracking Module was used to evaluate the impacts of river inputs (the Yangtze River and the Qiantang River), atmospheric deposition, Kuroshio intrusion, and water transport from the Taiwan Strait on the inventory of dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) in the sea areas adjacent to the Yangtze River Estuary, as well as their contributions to primary production. The results show that the contributions of river inputs, atmospheric deposition, Kuroshio intrusion, and water transport from the Taiwan Strait to the annual average inventory of DIN in the sea areas adjacent to the Yangtze River Estuary are 40%, 17%, 26%, and 17%, respectively. Among them, the DIN input by rivers supports about 37% of the primary production. The contributions of Kuroshio intrusion and water transport from the Taiwan Strait to the annual average inventory of DIP in the sea areas adjacent to the Yangtze River Estuary are 50% and 40%, respectively, and their contributions to primary production are 32% and 49%, respectively. After being utilized by phytoplankton, the new nutrients of the Kuroshio are transformed into regenerated nutrients. Both of them support the primary production in the waters adjacent to the Yangtze River Estuary. Among them, the inventory of regenerated nutrients of the Kuroshio is less than that of new nutrients, but it supports more primary production. Further analysis shows that river inputs and Kuroshio intrusion dominate the nutrient budgets and primary production in the areas shallower and deeper than the 50 m isobath, respectively. The results of this study provide scientific support for marine environmental protection and fishery resource management.