Cyanobacteria blooms in the Gulf of Finland triggered by saltwater inflow into the Baltic Sea
Cyanobacteria blooms in the Gulf of Finland triggered by saltwater inflow into the Baltic Sea
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DOI：
10.3354/meps207013
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发表时间：
2000-01-01
影响因子：
2.5
通讯作者：
Savchuk, OP
中科院分区：
文献类型：
--
作者：
Kahru, M;Leppänen, JM;Savchuk, OP
在1995年前的20世纪80年代和90年代，波罗的海发生了大量的重氮型蓝藻海藻水华，但从未延伸到芬兰湾中部和东部。在高氮磷比的波罗的海部分地区(如芬兰湾)没有固氮蓝藻水华的原因是它们在磷限制的条件下竞争优势降低。卫星传感器和现场监测都发现，从1995年夏天开始，芬兰海湾中部和东部出现了大量的海绵微藻水华。我们认为，海藻水华的东扩是由1993年咸水流入波罗的海引发的。随着1995年芬兰湾咸水和缺氧水域的到来，底层的分层增加，氧气浓度下降，从沉积物中释放出的磷酸盐数量增加。随后N：P比的降低可能是导致N，spumigena水华再次出现的原因。
In the 1980s and 1990s prior to 1995, massive blooms of the diazotrophic cyanobacterium Nodularia spumigena occurred in the Baltic Sea Proper but never extended into the central and eastern Gulf of Finland. The absence of nitrogen-fixing cyanobacteria blooms in parts of the Baltic Sea with a high N:P ratio (e.g. Gulf of Finland) has been explained by their reduced competitive advantage in conditions of P limitation. Starting with the summer of 1995, massive blooms of N. spumigena occurred in the central and eastern Gulf of Finland, as detected by both satellite sensors and in situ monitoring. We propose that the eastward expansion of N. spumigena blooms was triggered by the 1993 saltwater inflow into the Baltic. With the arrival of the saline and oxygen-depleted waters in the Gulf of Finland in 1995, stratification in the bottom layers increased, oxygen concentrations decreased, and increased amounts of phosphate were released from the sediments. The subsequent decrease in the N:P ratio may have caused the reoccurring N, spumigena blooms.