LINKING WATER QUALITY TO LIVING RESOURCES IN A MID-ATLANTIC LAGOON SYSTEM, USA
LINKING WATER QUALITY TO LIVING RESOURCES IN A MID-ATLANTIC LAGOON SYSTEM, USA
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将美国大西洋中部泻湖系统的水质与生物资源联系起来
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
R. Orth
中科院分区：
文献类型：
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作者：
Catherine E. Wazniak;M. R. Hall;T. Carruthers;Brian Sturgis;W. Dennison;R. Orth
大西洋中部沿岸海湾是浅海沿岸泻湖，由屏障沙岛与大西洋隔开，海洋交换仅限于狭窄的入口。这些泻湖系统的冲水量相对较差，使它们容易受到人为营养物负荷造成的富营养化的影响。一项密集的水质和海草监测计划被启动，以跟踪马里兰州和弗吉尼亚州沿海海湾的生态变化。本研究的目的是分析现有的监测数据，以确定富营养化的状况和趋势，并确定水质与生物资源之间的任何联系。对监测项目数据的分析揭示了以下几个趋势：(1)养分和叶绿素浓度的年代际下降，随后呈近期上升趋势；(2)海草盖度的年代际增加，随后在最近一段时间内没有变化；(3)大藻和褐潮微藻大量繁殖；(4)在马里兰州沿海海湾的许多地区，水质阈值超标：叶绿素a （15 lg/L）、总氮（0.65 mg/L或46 lmol/L）、总磷（0.037 mg/L或1.2 lmol/L）和溶解氧（5 mg/L）。水质阈值以生物资源（海草和鱼类）的生境要求为基础，用于计算水质指数，并用于比较海湾段。水体质量的强梯度与海草盖度的段间变化有关。这些因素表明，这些沿海海湾正处于过渡状态，一系列指标表明情况正在恶化。将需要继续监测和加强管理，以避免已观察到的富营养化趋势恶化。由于人类压力的增加，世界各地的沿海泻湖正经历着类似的退化趋势，评估与生物学相关的阈值有关的状况和趋势可以帮助确定监测和管理的优先事项和目标。
The mid-Atlantic coastal bays are shallow coastal lagoons, separated from the Atlantic Ocean by barrier sand islands with oceanic exchanges restricted to narrow inlets. The relatively poor flushing of these lagoon systems makes them susceptible to eutrophication resulting from anthropogenic nutrient loadings. An intensive water quality and seagrass monitoring program was initiated to track ecological changes in the Maryland and Virginia coastal bays. The purpose of this study was to analyze existing monitoring data to determine status and trends in eutrophication and to determine any associations between water quality and living resources. Analysis of monitoring program data revealed several trends: (1) decadal decreases in nutrient and chlorophyll concentrations, followed by recently increasing trends; (2) decadal increases in seagrass coverage, followed by a recent period of no change; (3) blooms of macroalgae and brown tide microalgae; and (4) exceedance of water quality thresholds: chlorophyll a (15 lg/L), total nitrogen (0.65 mg/L or 46 lmol/L), total phosphorus (0.037 mg/L or 1.2 lmol/L), and dissolved oxygen (5 mg/L) in many areas within the Maryland coastal bays. The water quality thresholds were based on habitat requirements for living resources (seagrass and fish) and used to calculate a water quality index, which was used to compare the bay segments. Strong gradients in water quality were correlated to changes in seagrass coverage between segments. These factors indicate that these coastal bays are in a state of transition, with a suite of metrics indicating degrading conditions. Continued monitoring and intensified management will be required to avert exacerbation of the observed eutrophication trends. Coastal lagoons worldwide are experiencing similar degrading trends due to increasing human pressures, and assessing status and trends relative to biologically relevant thresholds can assist in determining monitoring and management priorities and goals.