Diurnal carbon dynamics in a mangrove-dominated tropical estuary (Sundarbans, India)
Diurnal carbon dynamics in a mangrove-dominated tropical estuary (Sundarbans, India)
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DOI：
10.1016/j.ecss.2019.106426
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发表时间：
2019-11
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通讯作者：
M. K. Dutta;Sanjeev Kumar;Rupa Mukherjee;N. Sharma;Avanti Acharya;P. Sanyal;Ravi Bhusan;S. Mukhopadhyay
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作者：
M. K. Dutta;Sanjeev Kumar;Rupa Mukherjee;N. Sharma;Avanti Acharya;P. Sanyal;Ravi Bhusan;S. Mukhopadhyay
基于 24 小时的时间序列研究，我们报告了潮汐循环对位于印度东部以红树林为主的热带河口（孙德尔本斯）碳生物地球化学的影响。盐度、溶解氧和pH值显示出明显的潮汐变化，高潮时的值比低潮时的值相对较高。溶解无机碳（DIC）浓度变化范围较窄（1.92-2.19mM），退潮时数值相对较高；然而，δ13CDIC 却出现了相反的趋势，具有显着的变异性（– 4.28 至 – 2.21‰）。退潮期间，随着河口混合，生物地球化学（如有机碳矿化、硫酸盐还原和反硝化）和水文过程（孔隙水交换）对DIC动力学影响的初步证据被发现。 δ13CDIC-DIC 关系表明海洋浮游生物的呼吸是 DIC 的可能来源之一。溶解的有机碳在高潮期间显示出潮汐影响，在低潮期间显示出孔隙水介导的添加信号。颗粒有机碳和颗粒氮浓度在低潮期间达到最大值，稳定同位素组成主要显示海洋特征以及河口内生物地球化学改变的可能性。海水的贡献加上有机碳矿化和可能的孔隙水流入，导致低潮期间的 pCO2 比高潮高约 214μatm，FCO2 高 1.13 倍。每天，河口每平方米表面积向区域大气释放约 1348 毫克二氧化碳。
Based on a 24h of time-series study, we report the effects of a tidal cycle on carbon biogeochemistry of a mangrove dominated tropical estuary (the Sundarbans) located in the eastern part of India. Salinity, dissolved oxygen, and pH showed clear tidal variability with relatively higher values during high tide than low tide. Dissolved inorganic carbon (DIC) concentrations varied over a narrow range (1.92–2.19 mM) with relatively higher values during low tide; reverse trend, however, was noticed for δ13CDICwith significant variability (– 4.28 to – 2.21‰). During low tide, along with estuarine mixing, preliminary evidences for influences of biogeochemical (such as organic carbon mineralization, sulfate reduction, and denitrification) and hydrological processes (porewater exchange) were found on DIC dynamics. The δ13CDIC- DIC relationship suggested respiration of marine plankton to be one of the possible sources for DIC. Dissolved organic carbon showed tidal influence during high tide with a signal of porewater mediated addition during low tide. Both particulate organic carbon and particulate nitrogen concentrations reached the maximum during low tide with stable isotopic compositions showing predominantly marine signature along with the possibility of biogeochemical modifications within the estuary. Marine water contribution together with organic carbon mineralization and possible porewater influx resulted in ~214 μatm higherpCO2and 1.13 times higherFCO2during low tide than high tide. On diurnal basis, the estuary released ~1348 mg CO2per m2of surface area to the regional atmosphere.