The long-term freshening and nutrient increases in summer surface water in the northern East China Sea in relation to Changjiang discharge variation
The long-term freshening and nutrient increases in summer surface water in the northern East China Sea in relation to Changjiang discharge variation
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DOI：
10.1029/2008jc004812
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发表时间：
2008-10
影响因子：
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通讯作者：
E. Siswanto;H. Nakata;Yuji Matsuoka;Katsuhisa Tanaka;Y. Kiyomoto;Kazumaro Okamura;Jianrong Zhu;J. Ishizaka
中科院分区：
文献类型：
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作者：
E. Siswanto;H. Nakata;Yuji Matsuoka;Katsuhisa Tanaka;Y. Kiyomoto;Kazumaro Okamura;Jianrong Zhu;J. Ishizaka
利用历史现场资料，研究了东海北部夏季表层盐度和溶解无机氮浓度（DIN）的长期变化。1950 - 2002年，海表盐度呈现年际变化和年代际变化，长期呈下降趋势。随着长江流量的增加，风场和地面环流对盐度的年际变化有一定的影响。虽然我们将地表盐度的长期下降归因于长江流量的长期增加，但1978 - 1988年的高盐度似乎与黑潮输送的增加有关。1971 - 2001年DIN的增加可能是长江流量变化和中国氮肥使用量增加的共同作用。DIN的长期增加改变了营养成分，这意味着ECS北部的生物生产从限制DIN转变为限制磷。未来几十年，由于持续的人为扰动和气候变化，长江流量及其物理、化学性质可能会发生巨大变化，因此需要关注长江北部生态系统的变化。
[1] Using historical in situ data sets, we investigated long-term variations in summer surface salinity and dissolved inorganic nitrogen concentration (DIN) in the northern East China Sea (ECS). From 1950 to 2002, there were interannual and decadal variations in sea surface salinity, as well as a long-term decrease. Along with the Changjiang discharge, wind fields and surface circulations appeared to play roles in determining the interannual salinity variation. Although we attributed the long-term decrease in surface salinity to a long-term increase in the Changjiang discharge, the high salinity between 1978 and 1988 appeared to be associated with an increase in the Kuroshio Current transport. The increase in DIN from 1971 to 2001 appeared to be caused by a combination of changes in Changjiang discharge and an increase in nitrogen fertilizer use in China. The long-term increase in DIN modified the nutrient composition, implying that biological production in the northern ECS changed from a DIN-limiting to a phosphorous-limiting. We should pay attention to changes in the northern ECS ecosystem in future decades because the volume of the Changjiang discharge, as well as its physical and chemical properties, may change dramatically because of the continuous anthropogenic perturbations and climate change.