Variability in Dissolved Oxygen and Other Water-Quality Variables Within the National Estuarine Research Reserve System
Variability in Dissolved Oxygen and Other Water-Quality Variables Within the National Estuarine Research Reserve System
复制标题
国家河口研究储备系统内溶解氧和其他水质变量的变化
DOI：
10.2112/si45-017.1
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发表时间：
2004
影响因子：
2.7
通讯作者：
Y. Chen
中科院分区：
文献类型：
--
作者：
E. Wenner;D. Sanger;M. Arendt;A. F. Holland;Y. Chen
摘要浅水河口生境的特点通常是广泛的年际和年内波动的水质变量，包括溶解氧，然而，短期的变化很少测量和表征的水质变量。利用1995 ~ 2000年连续采集的22个国家河口研究保护区（NERR）55个站位的水质数据，分析了河口系统和区域间的时空变化特征和比较条件。三因素方差分析（ANOVA）模型揭示了几个显着的年际和季节性差异的水质变量为许多网站内的一个储备采样，但是，相对于储备或区域的年际趋势并不明显。盐度和缺氧事件（溶解氧[DO] < 28%饱和度[sat]）通常在夏季或秋季最大。蒸发蒸腾和降水量的影响，季节性的盐度模式在保护区网站。在热带系统通过期间，记录了与降水事件相关的盐度的短期急剧下降和持续的长期下降。在风暴通过之前，水温突然下降，随着风暴强度的增加，冷却效果也随之增加。虽然缺氧发生在广泛的地理范围内，但主要发生在持续温暖的水条件下。低氧受纬度和气候的影响很大。大多数储备的缺氧持续时间持续不到12小时。在许多位置，增加的部署持续时间显示出增加缺氧条件（DO <28%sat）的时间百分比和减少过饱和（DO > 120%sat）的时间百分比。溶解氧的大波动，发生在短时间内在河口表明需要长期连续测量，以估计暴露于低DO的频率和持续时间。如果没有持续的监测，许多低溶解氧事件将被错过，从而低估了这种类型的水质变化的潜在影响。NERR站点的水质数据的综合表明，保护区没有遇到许多问题，在其他人口较多的地方。
Abstract Shallow estuarine habitats are normally characterized by wide interannual and intraannual fluctuations in water-quality variables, including dissolved oxygen; however, the short-term variability in water-quality variables is seldom measured and characterized. Water-quality data collected semicontinuously by automated data sondes from 1995 to 2000 at 55 sites among 22 National Estuarine Research Reserves (NERR) were analyzed to characterize temporal variability and compare conditions among estuarine systems and regions. Three-way analysis of variance (ANOVA) models revealed several significant interannual and seasonal differences for water-quality variables for many sites sampled within a reserve; however, interannual trends with respect to reserve or region were not readily apparent. Salinity and hypoxic events (dissolved oxygen [DO] < 28% saturation [sat]) were generally greatest in summer or fall. Evapotranspiration and precipitation appeared to influence seasonal salinity patterns at reserve sites. Abrupt short-term decreases and sustained long-term decreases in salinity associated with precipitation events were documented during the passage of tropical systems. An abrupt decrease in water temperature prior to storm passage was noted, with increasing cooling effects related to increasing storm intensity. Although hypoxia occurred over a broad geographic range, it was primarily experienced at sites with sustained warm water conditions. Hypoxia was strongly influenced by latitude and climate. Duration of hypoxia at most reserves persisted less than 12 hours. Increased deployment duration was shown to increase the percentage of time with hypoxic conditions (DO < 28% sat) and decrease the percentage of time with supersaturation (DO > 120% sat) at many sites. The large fluctuations in dissolved oxygen that occur over short time periods in estuaries demonstrate the need for long-term continuous measurements to estimate the frequency and duration of exposure to low DO. Without continuous monitoring, many low-DO events would have been missed, thus underestimating the potential impacts from this type of water-quality variability. The synthesis of water-quality data from the NERR sites indicates that reserves have not experienced many of the problems found in other more populated locales.