Painting S J, Devlin M J, Malcolm S J, Parker E R, Mills D K, Mills C, Tett P, Wither A, Burt J, Jones R, Winpenny K
The Centre for Environment, Fisheries and Aquaculture Science, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK.
Mar Pollut Bull. 2007;55(1-6):74-90. doi: 10.1016/j.marpolbul.2006.08.020. Epub 2006 Oct 9.
The main aim of this study was to develop a generic tool for assessing risks and impacts of nutrient enrichment in estuaries. A simple model was developed to predict the magnitude of primary production by phytoplankton in different estuaries from nutrient input (total available nitrogen and/or phosphorus) and to determine likely trophic status. In the model, primary production is strongly influenced by water residence times and relative light regimes. The model indicates that estuaries with low and moderate light levels are the least likely to show a biological response to nutrient inputs. Estuaries with a good light regime are likely to be sensitive to nutrient enrichment, and to show similar responses, mediated only by site-specific geomorphological features. Nixon's scale was used to describe the relative trophic status of estuaries, and to set nutrient and chlorophyll thresholds for assessing trophic status. Estuaries identified as being eutrophic may not show any signs of eutrophication. Additional attributes need to be considered to assess negative impacts. Here, likely detriment to the oxygen regime was considered, but is most applicable to areas of restricted exchange. Factors which limit phytoplankton growth under high nutrient conditions (water residence times and/or light availability) may favour the growth of other primary producers, such as macrophytes, which may have a negative impact on other biological communities. The assessment tool was developed for estuaries in England and Wales, based on a simple 3-category typology determined by geomorphology and relative light levels. Nixon's scale needs to be validated for estuaries in England and Wales, once more data are available on light levels and primary production.
本研究的主要目的是开发一种通用工具，用于评估河口营养物质富集的风险和影响。开发了一个简单模型，以根据营养物质输入（总有效氮和/或磷）预测不同河口浮游植物的初级生产规模，并确定可能的营养状态。在该模型中，初级生产受到水体停留时间和相对光照条件的强烈影响。该模型表明，光照水平低和中等的河口对营养物质输入最不可能表现出生物响应。光照条件良好的河口可能对营养物质富集敏感，并表现出相似的响应，仅由特定地点的地貌特征介导。使用尼克松量表来描述河口的相对营养状态，并设定评估营养状态的营养物质和叶绿素阈值。被确定为富营养化的河口可能不会表现出任何富营养化迹象。评估负面影响时需要考虑其他属性。在此，考虑了对氧状况可能的损害，但这最适用于交换受限的区域。在高营养条件下限制浮游植物生长的因素（水体停留时间和/或光照可用性）可能有利于其他初级生产者的生长，如大型植物，这可能对其他生物群落产生负面影响。该评估工具是基于由地貌和相对光照水平确定的简单三分类类型学为英格兰和威尔士的河口开发的。一旦有更多关于光照水平和初级生产的数据，尼克松量表需要在英格兰和威尔士的河口进行验证。
