Dept. Biogeochemistry, Institute for Geology, Hamburg University, Hamburg, Germany.
Institute for Meteorology, Hamburg University, Hamburg, Germany.
Environ Monit Assess. 2021 Sep 29;193(10):677. doi: 10.1007/s10661-021-09189-6.
International harmonisation of management goals for eutrophication processes in coastal waters, requiring reduction of discharges and depositions of nutrients and organic matter, needs coordinated assessments and measures. This is especially necessary in open areas, connected by currents and mixing processes with trans-boundary exchanges. Management goals, defined nationally as local thresholds for nutrients and chlorophyll-a, had been applied recently (2006-2014) within international eutrophication assessments in the North Sea (OSPAR) and Baltic Sea (HELCOM). Consistency of thresholds for nitrogen nutrients and chlorophyll-a concentrations is tested by mixing diagrams and correlations between nitrogen nutrients (total and inorganic nitrogen) and chlorophyll-a. Results indicate mean consistent relations, but single deviations as in the continental coastal water of the North Sea surpassed means by a factor up to 5 for chlorophyll-a in relation to inorganic nitrogen. Thresholds differed across national borders significantly. Correlations of thresholds and assed data reflect the degree of regional deviations by comparison. Consistency of regionally applied thresholds can be achieved stepwise, by application of regionally correlated means, by adaptation to mixing and parameter relations, and finally by relations of thresholds to natural background concentrations. By this, consistency of international assessments can be improved generally, allowing coordinated management of open coastal waters.
国际上协调管理沿海富营养化过程的目标，需要减少营养物质和有机物的排放和沉积，需要协调的评估和措施。在与跨界交换相关的水流和混合过程相连的开阔区域，这一点尤为必要。管理目标在国家层面上被定义为营养物质和叶绿素-a 的本地阈值，最近（2006-2014 年）在北海（OSPAR）和波罗的海（HELCOM）的国际富营养化评估中得到了应用。通过混合图和氮营养物质（总氮和无机氮）与叶绿素-a 之间的相关性来测试氮营养物质和叶绿素-a 浓度的阈值的一致性。结果表明存在平均一致的关系，但在北海的大陆沿海地区存在单个偏差，其叶绿素-a 与无机氮的关系超过平均值的 5 倍。国家间的阈值差异显著。阈值和评估数据的相关性反映了区域偏差的程度。通过应用区域相关的平均值、通过混合和参数关系的适应性以及最后通过阈值与自然背景浓度的关系，可以逐步实现区域应用阈值的一致性。通过这种方式，可以普遍提高国际评估的一致性，从而协调开放沿海水域的管理。
