Eberlein K
Universitäts-Krankenhaus Eppendorf, Hamburg.
Zentralbl Hyg Umweltmed. 1994 Dec;196(4):285-311.
The situation of inorganic nutrients (nitrate, ammonia, phosphate, and silicate) in the German Bight was studied during several cruises and found to be very different in early summer of different years. Because of the many permanently changing processes which govern nutrient concentrations, an exact interpretation of the results is difficult. Impact on nutrient situation is given mainly by input from land runoff and rivers, by import from other sea regions, by atmospheric input, by horizontal and vertical mixing of imported substances, by incorporation into living organisms, as well as by the release from biological material. In spite of the most complex nutrient situation the presented data demonstrate the anthropogenic burden on the German Bight in a high degree. In early summer nearly all nitrate and phosphate would be used up by phytoplankton under natural conditions. But nutrients are supplied continuously by river input. On their way into the German Bight they are distributed within the area of the plume of riverine water coming from the rivers Elbe and Weser. Here they are taken up by phytoplankton as long as phosphate is available. This results in water bodies with a high surplus of nitrogen and little growth of phytoplankton, since phosphate is missing then. In many parts of the German Bight phosphate concentrations are below the detection limit in early summer, in spite of the high anthropogenic input. In the area of the fresh water plume the ratio of nitrogen containing nutrients to phosphate can reach a maximum of 3000:1 instead of 15:1, which would be found under natural conditions. The drastic shifting of nutrient ratios is man made and supposed to result in an increase of toxic algal blooms and in a change of the natural phytoplankton species composition of the German Bight. In consequence significant changes of the existing ecosystem are to be suspected. At areas where water bodies rich in nitrate and poor in phosphate get mixed with phosphate containing water bodies, rapid growth of algal blooms is possible. Onset and localities of such events are not predictable, as long as the meteorological and hydrographic conditions as well as the chemical situation are not known exactly. But this would require permanent and high activities of several research vessels in summer half-year. Nevertheless it would hardly be predictable which of the many different phytoplankton species would bloom. Onset, localities and intensities of consequential damages on exceptional algal blooms as accumulation of foam on beaches are not predictable, too.(ABSTRACT TRUNCATED AT 400 WORDS)
在多次巡航期间，对德国湾无机营养物质（硝酸盐、氨、磷酸盐和硅酸盐）的情况进行了研究，发现不同年份的初夏情况差异很大。由于许多持续变化的过程控制着营养物质的浓度，因此很难对结果进行准确解读。对营养状况的影响主要来自陆地径流和河流的输入、其他海域的输入、大气输入、输入物质的水平和垂直混合、纳入生物体以及生物物质的释放。尽管营养状况极为复杂，但所呈现的数据高度显示了德国湾的人为负担。在初夏的自然条件下，几乎所有的硝酸盐和磷酸盐都会被浮游植物耗尽。但河流输入持续供应营养物质。在它们进入德国湾的途中，这些营养物质分布在来自易北河和威悉河的河水羽流区域内。只要有磷酸盐，浮游植物就会在这里吸收它们。这导致水体中氮大量过剩，浮游植物生长很少，因为那时缺少磷酸盐。尽管人为输入量很大，但在初夏德国湾的许多地方，磷酸盐浓度低于检测限。在淡水羽流区域，含氮营养物质与磷酸盐的比例可达3000:1，而不是自然条件下会出现的15:1。营养比例的急剧变化是人为造成的，预计会导致有毒藻华增加以及德国湾自然浮游植物物种组成发生变化。因此，现有生态系统可能会发生重大变化。在富含硝酸盐而贫磷酸盐的水体与含磷酸盐的水体混合的区域，藻华有可能迅速生长。只要气象、水文条件以及化学状况不完全清楚，此类事件的发生时间和地点就无法预测。但这需要在夏季半年有几艘研究船持续进行高强度作业。然而，很难预测众多不同的浮游植物物种中哪一种会形成藻华。异常藻华造成的后果性损害，如海滩上泡沫堆积的发生时间、地点和强度也无法预测。
