Estuaries and Coasts ( IF 2.7 ) Pub Date : 2021-07-16 , DOI: 10.1007/s12237-021-00983-6 Rachel Henderson 1 , Paul A. Bukaveckas 1
Upper estuarine segments are characterized by mixing of diverse source waters with a variety of constituents that may influence water clarity (e.g., algae, inorganic particulates, dissolved color). We measured turbidity, total suspended solids (TSS), chlorophyll-a (CHLa), dissolved organic carbon (DOC), and chromophoric dissolved organic matter (CDOM) in upper segments of the James and York Estuaries to better understand their role in light attenuation. Turbidity and TSS were found to be the best predictors of inter-site and intra-site variations in light attenuation. CHLa was not found to be a strong predictor of light attenuation, indicating that suspended particulate matter was largely non-algal. CDOM played a greater role in light attenuation in the Pamunkey and Mattaponi sub-estuaries, which derive a greater proportion of their inflow from lowland (Coastal Plain) sources where extensive wetlands and floodplain forest likely serve as a source of CDOM. Although dissolved and particulate components of light attenuation were derived from external (watershed) sources, variation in external inputs (river discharge) was not a strong predictor of estuarine light attenuation. Analysis of long-term (25-year) data indicate trends of decreasing turbidity and increasing water clarity at some sites, coinciding with decreases in river sediment inputs. In the James Estuary, underwater light conditions remain below targets for successful SAV colonization and favor phytoplankton-dominated primary production. Management actions that reduce sediment loads are likely to be the most effective means for improving water clarity in upper estuarine segments.
中文翻译:
詹姆斯河口和约克河口上段光衰减的控制因素及其对初级生产者的影响
河口上游段的特点是多种源水与可能影响水透明度的各种成分(例如,藻类、无机颗粒、溶解颜色)混合。我们测量了詹姆斯河口和约克河口上段的浊度、总悬浮固体 (TSS)、叶绿素 a (CHLa)、溶解有机碳 (DOC) 和发色溶解有机物 (CDOM),以更好地了解它们在光衰减中的作用. 浊度和 TSS 被发现是光衰减的站点间和站点内变化的最佳预测指标。没有发现 CHLa 是光衰减的强预测因子,表明悬浮颗粒物主要是非藻类。CDOM 在 Pamunkey 和 Mattaponi 子河口的光衰减方面发挥了更大的作用,它们从低地(沿海平原)来源获得更大比例的流入,其中广阔的湿地和漫滩森林可能是 CDOM 的来源。尽管光衰减的溶解和颗粒成分来自外部(流域)源,但外部输入(河流流量)的变化并不是河口光衰减的强预测因子。对长期(25 年)数据的分析表明,某些地点的浊度降低和水清澈度增加的趋势与河流沉积物输入的减少相吻合。在詹姆斯河口,水下光照条件仍然低于 SAV 成功定殖的目标,有利于浮游植物主导的初级生产。