Seasonal responses in estuarine metabolism (primary production, respiration, and net metabolism) were examined using two complementary approaches. Total ecosystem metabolism rates were calculated from dissolved oxygen time series using Odum’s open water method. Water column rates were calculated from oxygen-based bottle experiments. The study was conducted over a spring-summer season in the Pensacola Bay estuary at a shallow seagrass-dominated site and a deeper bare-bottomed site. Water column integrated gross production rates more than doubled (58.7 to 130.9 mmol O₂ m⁻² day⁻¹) from spring to summer, coinciding with a sharp increase in water column chlorophyll-a, and a decrease in surface salinity. As expected, ecosystem gross production rates were consistently higher than water column rates but showed a different spring-summer pattern, decreasing at the shoal site from 197 to 168 mmol O₂ m⁻² day⁻¹ and sharply increasing at the channel site from 93.4 to 197.4 mmol O₂ m⁻² day⁻¹. The consistency among approaches was evaluated by calculating residual metabolism rates (ecosystem − water column). At the shoal site, residual gross production rates decreased from spring to summer from 176.8 to 99.1 mmol O₂ m⁻² day⁻¹ but were generally consistent with expectations for seagrass environments, indicating that the open water method captured both water column and benthic processes. However, at the channel site, where benthic production was strongly light-limited, residual gross production varied from 15.7 mmol O₂ m⁻² day⁻¹ in spring to 86.7 mmol O₂ m⁻² day⁻¹ in summer. The summer rates were much higher than could be realistically attributed to benthic processes and likely reflected a violation of the open water method due to water column stratification. While the use of sensors for estimating complex ecosystem processes holds promise for coastal monitoring programs, careful attention to the sampling design, and to the underlying assumptions of the methods, is critical for correctly interpreting the results. This study demonstrated how using a combination of approaches yielded a fuller understanding of the ecosystem response to hydrologic and seasonal variability.

中文翻译：

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温带河口的季节性氧气动力学：水文变异性对初级生产，呼吸和净代谢的测量的影响。

使用两种补充方法检查了河口新陈代谢的季节性响应（主要产生，呼吸和净代谢）。使用Odum的开阔水域方法，根据溶解氧时间序列计算了生态系统总代谢率。从基于氧气的瓶实验中计算出水柱速率。这项研究是在春季和夏季在彭萨科拉湾河口的一个浅海草为主的地方和一个更深的裸底地方进行的。水柱综合总生产率翻了一番以上（58.7至130.9 mmol O ₂ m ^-2 天^-1）从春季到夏季，这与水柱叶绿素a的急剧增加和表面盐度的降低相吻合。正如预期的那样，生态系统总生产率始终高于水柱速率，但呈现出不同的春夏季模式，在浅滩位置从197降至168 mmol O ₂ m ^-2 天^-1，在河道位置从93.4急剧增加至197.4 mmol O ₂ m ^-2 天^-1。通过计算残留代谢率（生态系统-水柱）评估方法之间的一致性。在浅滩处，春季至夏季的剩余总生产率从176.8降至99.1 mmol O ₂ m ^-2 第^-1天，但通常与对海草环境的预期一致，表明开放水法同时捕获了水柱和底栖生物。但是，在底栖生产受光强限制的航道处，残留总生产量从春季的15.7 mmol O ₂ m ^-2 天^-1到86.7 mmol O ₂ m ^-2 天^-1有所不同。在夏天。夏季的比率要比实际归因于底栖过程的比率高得多，并且很可能反映出由于水柱分层而违反了开放水法。尽管使用传感器来估计复杂的生态系统过程为沿海监测计划带来了希望，但对采样设计以及方法的基本假设的仔细关注对于正确地解释结果至关重要。这项研究表明，如何结合使用多种方法可以更全面地了解生态系统对水文和季节变化的响应。