Drivers of pCO2 variability in two contrasting coral reef lagoons: The influence of submarine groundwater discharge
Drivers of pCO2 variability in two contrasting coral reef lagoons: The influence of submarine groundwater discharge
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DOI：
10.1002/2013gb004598
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发表时间：
2014-04-01
影响因子：
5.2
通讯作者：
Eyre, Bradley D.
中科院分区：
文献类型：
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作者：
Cyronak, Tyler;Santos, Isaac R.;Eyre, Bradley D.
在两个具有不同海底地下水排放(SGD)驱动因素的珊瑚礁泻湖中，评估了地下水对PCO(2)变异性的影响。PCO(2)在两个生态系统中的Diel变异性可由生物驱动因素和SGD输入相结合来解释。在南太平洋火山岛拉罗通加，Rn-222衍生的SGD主要受陡峭的陆地水力梯度驱动，水柱受到淡水高PCO(2)(5501亩ATM)的影响。在大堡礁珊瑚礁Heron Island，SGD主要受海水通过沉积物再循环(即潮汐抽水)的影响，而PCO(2)主要受生物过程的刺激。拉罗通加水柱的平均PCO(2)(549亩ATM)高于苍鹭岛(471亩ATM)。然而，PCO(2)在苍鹭岛(778亩ATM)比在拉罗通加(507亩ATM)表现出更大的日变化范围。Rarotonga水柱从SGD获得29.08.2 mmol自由CO2 m(-2)d(-1)，苍鹭岛水柱从SGD获得12.14.2 mmol自由CO2 m(-2)d(-1)。在这项研究过程中，这两个系统都是大气中二氧化碳的来源，来自SGD的游离二氧化碳很可能对海-气之间的二氧化碳通量做出了很大贡献。衡量珊瑚礁碳化学(如新陈代谢和钙化率)的研究可能需要考虑地下水输入对水柱碳酸盐化学的影响。珊瑚礁碳酸盐化学的局部驱动因素，如SGD，可能提供更易接近的管理解决方案，以减轻海洋酸化对珊瑚礁的影响。关键点地下水可能会影响珊瑚礁中PCO(2)珊瑚礁中地下水的变异性可能会增强局部海洋酸化净群落钙化的测量可能会受到地下水的影响
The impact of groundwater on pCO(2) variability was assessed in two coral reef lagoons with distinct drivers of submarine groundwater discharge (SGD). Diel variability of pCO(2) in the two ecosystems was explained by a combination of biological drivers and SGD inputs. In Rarotonga, a South Pacific volcanic island, Rn-222-derived SGD was driven primarily by a steep terrestrial hydraulic gradient, and the water column was influenced by the high pCO(2) (5501 mu atm) of the fresh groundwater. In Heron Island, a Great Barrier Reef coral cay, SGD was dominated by seawater recirculation through the sediments (i.e., tidal pumping), and pCO(2) was mainly impacted through the stimulation of biological processes. The Rarotonga water column had a higher average pCO(2) (549 mu atm) than Heron Island (471 mu atm). However, pCO(2) exhibited a greater diel range in Heron Island (778 mu atm) than in Rarotonga (507 mu atm). The Rarotonga water column received 29.08.2 mmol free-CO2 m(-2) d(-1) from SGD, while the Heron Island water column received 12.14.2 mmol free-CO2 m(-2) d(-1). Over the course of this study, both systems were sources of CO2 to the atmosphere with SGD-derived free-CO2 most likely contributing a large portion to the air-sea CO2 flux. Studies measuring the carbon chemistry of coral reefs (e.g., metabolism and calcification rates) may need to consider the effects of groundwater inputs on water column carbonate chemistry. Local drivers of coral reef carbonate chemistry such as SGD may offer more approachable management solutions to mitigating the effects of ocean acidification on coral reefs.Key Points Groundwater can influence pCO(2) variability in coral reefs Submarine groundwater discharge may enhance local ocean acidification Measurements of net community calcification can be influenced by groundwater