Kuparinen J, Tuominen L
Department of Biological Oceanography, Finnish Institute of Marine Research, P.O. Box 33, FIN-00931 Helsinki, Finland.
Ambio. 2001 Aug;30(4-5):190-4.
During the 1990s nitrogen reserves have shown rising trends in the northern Baltic Sea. Changes in denitrification explain some of the fluctuations observed in nitrogen reserves. Although denitrification is an anaerobic process, the most efficient removal of nitrogen by denitrification occurs where the sediment is moderately well oxidized. A dramatic decrease in the ratio of SiO4 to DIN (DIN = NO3 + NH4) in the northern Baltic proper during the period 1973-1999 was recorded. If dissolved silica limits phytoplankton spring bloom, diatom blooms fade and become replaced by flagellates leading to changes in summer phosphate reserves and sedimentation. Seven years have elapsed from the previous strong saltwater inflow and anoxia has spread over large areas. Deep bottom phosphorus levels have started to increase and denitrification capacity is weakening. Thus, all efforts to minimize N- and P-loading will, in the long run, help the Baltic Sea to recover from the unacceptable status of eutrophication.
在20世纪90年代，波罗的海北部的氮储量呈上升趋势。反硝化作用的变化解释了氮储量中观察到的一些波动。虽然反硝化作用是一个厌氧过程，但通过反硝化作用最有效地去除氮发生在沉积物被适度氧化的地方。在1973年至1999年期间，波罗的海北部适当区域的SiO4与DIN（DIN = NO3 + NH4）的比例记录到急剧下降。如果溶解硅限制了浮游植物的春季水华，硅藻水华就会消退并被鞭毛虫取代，从而导致夏季磷酸盐储量和沉积的变化。自上次强烈的海水流入以来已经过去了七年，缺氧已经蔓延到大片区域。深层底部的磷含量开始增加，反硝化能力正在减弱。因此，从长远来看，所有尽量减少氮和磷负荷的努力将有助于波罗地海从不可接受的富营养化状态中恢复过来。
