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首页> 外文期刊>Aquatic Sciences >Short-term variation in thermal stratification complicates estimation of lake metabolism
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Short-term variation in thermal stratification complicates estimation of lake metabolism

机译：热分层的短期变化使湖泊新陈代谢的估计复杂化

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摘要

Previous studies have used sondes to measure diel changes in dissolved oxygen and thereby estimate gross primary production (GPP), ecosystem respiration (R), and net ecosystem production (NEP). Most of these studies estimate rates for the surface layer and require knowing the depth of the mixed layer (Z_(mix)), which is usually determined from discrete daily or weekly temperature profiles. However, Z_(mix) is dynamic, as the thermal structure of lakes may change at scales of minutes rather than days or weeks. We studied two thermally stratified lakes that exhibited intermittent microstratification in the mixed layer. We combined sonde-based estimates of metabolism with high-frequency measurements of stratification using thermistor chains to determine how the short-term dynamics of stratification affect metabolic rates. We calculated estimates of metabolism using time series of Z_(mix) measured at seasonal, weekly, daily, and 5-min intervals. Areal rates of GPP and R were up to 24 and 29% less, respectively, using the 5-min measurements of Z_(mix) rather than weekly Z_(mix), while NEP was not significantly different. These reduced areal rates are mostly the consequence of the reduction in the depth of the mixed layer. Microstratification occurred frequently in both lakes and affected volumetric rates in one lake where R was significantly lower, NEP was significantly higher, and GPP was marginally lower compared to days without microstratification. Hence, microstratification not only affects the depth of the mixed layer, but also alters the processes that influence photosynthesis and respiration. Future studies should consider microstratification and possibly employ multiple sondes with thermistor chains that enable integrating metabolic rates to a specific depth, rather than assuming a stable upper mixed layer as the basis for calculations.
机译：先前的研究使用探测仪测量溶解氧中diel的变化，从而估算初级总产值（GPP），生态系统呼吸（R）和净生态系统产量（NEP）。这些研究大多数估计表面层的速率，并且需要知道混合层的深度（Z_（mix）），该深度通常由离散的每日或每周温度曲线确定。但是，Z_（mix）是动态的，因为湖泊的热结构可能会在几分钟而不是几天或几周的时间内发生变化。我们研究了在混合层中表现出间歇性微分层的两个热分层湖泊。我们将基于探空仪的新陈代谢估计值与使用热敏电阻链的高频分层测量结果结合起来，以确定分层的短期动态如何影响新陈代谢率。我们使用Z_（mix）的时间序列（按季节，每周，每天和5分钟间隔测量）来计算代谢估计值。使用Z_（mix）而不是每周的Z_（mix）的5分钟测量，GPP和R的实际比率分别降低了24％和29％，而NEP没有显着差异。这些减小的面积率主要是混合层深度减小的结果。与没有微分层的天数相比，这两个湖泊都经常发生微分层现象，并且在一个湖泊中发生了微分层，其中R显着降低，NEP显着更高，GPP略微降低。因此，微分层不仅影响混合层的深度，而且改变了影响光合作用和呼吸作用的过程。未来的研究应考虑微分层，并可能使用带有热敏电阻链的多个探头，这些探头能够将代谢速率整合到特定深度，而不是以稳定的上层混合层为计算基础。

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  • 来源
    《Aquatic Sciences》 |2011年第2期|p.305-315|共11页
  • 作者

    James J. Coloso; Jonathan J. Cole; Michael L. Pace;

  • 作者单位

    Department of Environmental Sciences, University of Virginia,291 McCormick Rd, Charlottesville, VA 22904, USA,Cary Institute of Ecosystem Studies, P.O. Box AB, Millbrook,NY 12545, USA;

    Cary Institute of Ecosystem Studies, P.O. Box AB, Millbrook,NY 12545, USA;

    Department of Environmental Sciences, University of Virginia,291 McCormick Rd, Charlottesville, VA 22904, USA;

  • 收录信息 美国《科学引文索引》(SCI);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    lake metabolism; gross primary production; respiration; net ecosystem production; stratification;

    机译：湖泊新陈代谢;总初级生产;呼吸作用;净生态系统产量;分层;

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