The estimation of gross oxygen production and community respiration from autonomous time-series measurements in the oligotrophic ocean
The estimation of gross oxygen production and community respiration from autonomous time-series measurements in the oligotrophic ocean
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DOI：
10.1002/lom3.10340
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发表时间：
2019-11-20
影响因子：
2.7
通讯作者：
Karl, David
中科院分区：
文献类型：
--
作者：
Barone, Benedetto;Nicholson, David;Karl, David
氧浓度的昼夜变化已被广泛用于估算生产性淡水和海洋生态系统的光合作用和呼吸作用速率。光学氧传感器的最新改进现在使我们能够使用相同的方法来估计覆盖全球大部分海洋的贫营养沃茨的代谢率，并用于自动水下航行器收集的测量数据。通过建立在以前的方法，我们提出了一个程序来估计光合作用和呼吸作用的垂直分辨昼夜氧浓度的测量。该过程涉及将由于生物过程引起的氧变化与由于物理过程引起的变化分离，并使用线性最小二乘分析从生物氧变化计算代谢率。我们在北太平洋副热带环流表层的水下滑翔机观测上测试了我们的方法，在那里我们估计了总氧产生率和群落呼吸率，平均值均为1.0 mmol O-2 m（-3）d（-1），与以前对相同环境的估计一致。方法不确定度计算为拟合参数的标准差，平均值分别为0.6和0.5 mmol O-2 m（-3）d（-1），用于氧产生和呼吸。代谢率的变异性大于这种不确定性，我们能够辨别出生物生产和消耗氧气的协变。所提出的方法在约1周的时间尺度上解决了变异性。这种分辨率可以通过几种方式来提高，包括测量湍流混合，增加海洋表面的测量次数，以及在数据收集过程中采用拉格朗日方法。
Diel variations in oxygen concentration have been extensively used to estimate rates of photosynthesis and respiration in productive freshwater and marine ecosystems. Recent improvements in optical oxygen sensors now enable us to use the same approach to estimate metabolic rates in the oligotrophic waters that cover most of the global ocean and for measurements collected by autonomous underwater vehicles. By building on previous methods, we propose a procedure to estimate photosynthesis and respiration from vertically resolved diel measurements of oxygen concentration. This procedure involves isolating the oxygen variation due to biological processes from the variation due to physical processes, and calculating metabolic rates from biogenic oxygen changes using linear least squares analysis. We tested our method on underwater glider observations from the surface layer of the North Pacific Subtropical Gyre where we estimated rates of gross oxygen production and community respiration both averaging 1.0 mmol O-2 m(-3) d(-1), consistent with previous estimates from the same environment. Method uncertainty was computed as the standard deviation of the fitted parameters and averaged 0.6 and 0.5 mmol O-2 m(-3) d(-1) for oxygen production and respiration, respectively. The variability of metabolic rates was larger than this uncertainty and we were able to discern covariation in the biological production and consumption of oxygen. The proposed method resolved variability on time scales of approximately 1 week. This resolution can be improved in several ways including by measuring turbulent mixing, increasing the number of measurements in the surface ocean, and adopting a Lagrangian approach during data collection.