An ecosystem-based management of a large sea can give heterogeneous nutrient load targets for different parts of the sea. Cost effective solutions to heterogeneous nutrient reductions targets based on ecological conditions are compared with the same overall nutrient reductions to the Baltic Sea. To this end, a numerical programming model is used, which includes eight different nutrient abatement measures (fertilizer and livestock reduction, cultivation of catch crops, reduced airborne nitrogen emissions, improved cleaning at sewage treatment plants, construction of wetlands and buffer strips, and mussel farming) in 21 catchments of the Baltic Sea. The results indicate that the cost for the international agreement on maximum load targets to different marine basins amounts to 5.3 billion euro. This is more than twice as large as the cost for the same total nutrient load targets to the Baltic Sea without specific targets for the marine basins. However, the resulting nutrient loads to the different marine basins deviate from the basin targets where the loads are lower for some basins but can exceed that for one basin, Baltic Proper, by approximately 22 per cent. Whether or not the ecological costs and benefits from deviations in basin targets under the Baltic Sea targets exceed the excess abatement cost of 2.9 billion euro for achieving the marine basin targets remains to be verified.

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基于生态系统的营养目标的成本效益——波罗的海数值模型的发现

基于生态系统的大型海洋管理可以为海洋的不同部分提供不同的营养负荷目标。将基于生态条件的异构养分减少目标的成本效益解决方案与波罗的海相同的总体养分减少进行比较。为此，使用了一个数值编程模型，其中包括八种不同的养分减少措施（减少肥料和牲畜、种植捕获作物、减少空气中的氮排放、改善污水处理厂的清洁、湿地和缓冲带的建设以及贻贝农业）在波罗的海的 21 个集水区。结果表明，针对不同海洋盆地的最大负荷目标国际协议的成本达 53 亿欧元。这比没有特定海洋盆地目标的波罗的海的相同总养分负荷目标的成本高出两倍多。然而，由此产生的不同海洋盆地的养分负荷偏离了盆地目标，其中一些盆地的负荷较低，但可能超过波罗的海盆地的负荷约 22%。波罗的海目标下流域目标偏差的生态成本和收益是否超过实现海洋流域目标的 29 亿欧元超额减排成本仍有待验证。由此产生的不同海洋盆地的养分负荷偏离了盆地目标，其中一些盆地的负荷较低，但可能超过波罗的海盆地一个盆地的负荷约 22%。波罗的海目标下流域目标偏差的生态成本和收益是否超过实现海洋流域目标的 29 亿欧元超额减排成本仍有待验证。由此产生的不同海洋盆地的养分负荷偏离了盆地目标，其中一些盆地的负荷较低，但可能超过波罗的海盆地一个盆地的负荷约 22%。波罗的海目标下流域目标偏差的生态成本和收益是否超过实现海洋流域目标的 29 亿欧元超额减排成本仍有待验证。