The source and significance of two nutrients, nitrogen and phosphorous, were investigated by a modified dilution method performed on seawater samples from the Jiaozhou Bay, in autumn 2004. This modified dilution metho...The source and significance of two nutrients, nitrogen and phosphorous, were investigated by a modified dilution method performed on seawater samples from the Jiaozhou Bay, in autumn 2004. This modified dilution method accounted for the phytoplankton growth rate, microzooplankton grazing mortality rate, the internal and external nutrient pools, as well as nutrient supplied through remineralization by microzooplankton. The results indicated that the phytoplankton net growth rate increased in turn from inside the bay, to outside the bay, to in the Xiaogang Harbor. The phytoplankton maximum growth rates and microzooplankton grazing mortality rates were 1.14 and 0.92 d^-1 outside the bay, 0.42 and 0.32 d^ -1 inside the bay and 0.98 and 0.62 d^-1 in the harbor respectively. Outside the bay, the remineralized nitrogen （Kt = 24.49） had heavy influence on the growth of the phytoplankton. Inside the bay, the remineralized phosphorus（Kt = 3.49） strongly affected the phytoplankton growth. In the harbor, the remineralized phosphorus （Kt = 3.73） was in larger demand by phytoplankton growth. The results demonstrated that the dif- ferent nutrients pools supplied for phytoplankton growth were greatly in accordance with the phytoplankton community structure, microzooplankton grazing mortality rates and environmental conditions. It is revealed that nutrient remineralization is much more important for the phytoplankton growth in the Jiaozhou Bay than previously believed.展开更多
基金This study was supported by the Funds of the Chinese Academy of Sciences for Key Topics in Innovation Engineering under contract No.KZCX2-YW-213the National Natural Science Foundation of China under contract Nos 40306025 and 40676089.
文摘The source and significance of two nutrients, nitrogen and phosphorous, were investigated by a modified dilution method performed on seawater samples from the Jiaozhou Bay, in autumn 2004. This modified dilution method accounted for the phytoplankton growth rate, microzooplankton grazing mortality rate, the internal and external nutrient pools, as well as nutrient supplied through remineralization by microzooplankton. The results indicated that the phytoplankton net growth rate increased in turn from inside the bay, to outside the bay, to in the Xiaogang Harbor. The phytoplankton maximum growth rates and microzooplankton grazing mortality rates were 1.14 and 0.92 d^-1 outside the bay, 0.42 and 0.32 d^ -1 inside the bay and 0.98 and 0.62 d^-1 in the harbor respectively. Outside the bay, the remineralized nitrogen （Kt = 24.49） had heavy influence on the growth of the phytoplankton. Inside the bay, the remineralized phosphorus（Kt = 3.49） strongly affected the phytoplankton growth. In the harbor, the remineralized phosphorus （Kt = 3.73） was in larger demand by phytoplankton growth. The results demonstrated that the dif- ferent nutrients pools supplied for phytoplankton growth were greatly in accordance with the phytoplankton community structure, microzooplankton grazing mortality rates and environmental conditions. It is revealed that nutrient remineralization is much more important for the phytoplankton growth in the Jiaozhou Bay than previously believed.
