Temporal variability and driving factors of the carbonate system in the Aransas Ship Channel, TX, USA: a time series study
Temporal variability and driving factors of the carbonate system in the Aransas Ship Channel, TX, USA: a time series study
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DOI：
10.5194/bg-18-4571-2021
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发表时间：
2021-08
期刊：
影响因子：
4.9
通讯作者：
Melissa R. McCutcheon;H. Yao;Cory J. Staryk;Xinping Hu
中科院分区：
文献类型：
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作者：
Melissa R. McCutcheon;H. Yao;Cory J. Staryk;Xinping Hu
抽象。沿海海洋受到一系列同时发生的生物地球化学和人为过程的影响，导致水化学的巨大异质性，包括碳酸盐化学参数，如pH值和二氧化碳分压（pCO 2）。为了更好地了解海岸和河口酸化和海气CO2通量，重要的是研究碳酸盐化学的基线变异性和驱动因素。使用离散瓶样本采集（2014-2020）和每小时传感器测量（2016-2017），我们探索了位于墨西哥湾西北部的阿兰萨斯船舶通道碳酸盐系统（特别是pH值和pCO 2）从昼夜到年际尺度的时间变化。使用其他协同定位的环境传感器，我们还探索了这种变化的驱动因素。这两种采样方法都表现出显着的季节性变化的位置，最高的pH值（最低pCO 2）在冬季和最低的pH值（最高pCO 2）在夏季。从传感器数据中也可以明显看出显著的昼夜变化，但在整个监测期间，pCO 2升高和pH值降低的时间并不一致，有时与生物信号的预期相反。虽然季节性和昼夜波动比以前研究的许多其他领域小，碳酸盐化学参数是区分一天中的时间和季节之间的最重要的环境参数。很明显，温度，生物活动，淡水流入量和潮汐水位（尽管潮差很小）都是对系统的重要控制，不同的控制在不同的时间尺度上占主导地位。结果表明，碳酸盐系统的控制因素可能不会施加同样的pH值和pCO 2的昼夜时间尺度，造成分离的昼夜或潮汐关系在某些季节。尽管在较短的时间尺度上已知的时间变异性，离散采样一般代表平均碳酸盐系统和平均气-海CO2通量的季节和年度的基础上相比，传感器数据。
Abstract. The coastal ocean is affected by an array of co-occurring biogeochemical and anthropogenic processes, resulting in substantial heterogeneity in water chemistry, including carbonate chemistry parameters such as pH and partial pressure of CO2 (pCO2). To better understand coastal and estuarine acidification and air-sea CO2 fluxes, it is important to study baseline variability and driving factors of carbonate chemistry. Using both discrete bottle sample collection (2014–2020) and hourly sensor measurements (2016–2017), we explored temporal variability, from diel to interannual scales, in the carbonate system (specifically pH and pCO2) at the Aransas Ship Channel located in the northwestern Gulf of Mexico. Using other co-located environmental sensors, we also explored the driving factors of that variability. Both sampling methods demonstrated significant seasonal variability at the location, with highest pH (lowest pCO2) in the winter and lowest pH (highest pCO2) in the summer. Significant diel variability was also evident from sensor data, but the time of day with elevated pCO2 and depressed pH was not consistent across the entire monitoring period, sometimes reversing from what would be expected from a biological signal. Though seasonal and diel fluctuations were smaller than many other areas previously studied, carbonate chemistry parameters were among the most important environmental parameters for distinguishing between time of day and between seasons. It is evident that temperature, biological activity, freshwater inflow, and tide level (despite the small tidal range) are all important controls on the system, with different controls dominating at different timescales. The results suggest that the controlling factors of the carbonate system may not be exerted equally on both pH and pCO2 on diel timescales, causing separation of their diel or tidal relationships during certain seasons. Despite known temporal variability on shorter timescales, discrete sampling was generally representative of the average carbonate system and average air-sea CO2 flux on a seasonal and annual basis when compared with sensor data.