High CO2 evasion during floods in an Australian subtropical estuary downstream from a modified acidic floodplain wetland
High CO2 evasion during floods in an Australian subtropical estuary downstream from a modified acidic floodplain wetland
复制标题
DOI：
10.1002/lno.10004
复制
发表时间：
2015-01
影响因子：
4.5
通讯作者：
S. Ruíz‐Halpern;D. Maher;I. Santos;B. Eyre
中科院分区：
文献类型：
--
作者：
S. Ruíz‐Halpern;D. Maher;I. Santos;B. Eyre
研究了里士满河下游河口和一条排放酸性湿地的支流中与洪涝和洪灾后恢复有关的溶解CO2动态。暴雨(高达133 mm d−1)导致大流量(高达250×106m~3 d−1)在不到一天的时间内冲刷河口。二氧化碳分压(PCO2,2006pa或19,801μatm)的最大值出现在洪水后的恢复期。高的二氧化碳分压与洪泛区代谢产物通过地表径流和地下水的运输有关，也与滨海酸性硫酸盐土壤改良湿地的低pH(4.22)有关。仅有好氧呼吸作用不能解释河口二氧化碳浓度高的原因，在盐度0-20范围内形成了一个低缓冲区域。二氧化碳分压与里士满河主河道的淡水流量相关(R2=0.82；p0.05；n=7)。大气-水二氧化碳通量处于水生系统的高端(最大1413mmolCm−2d−1，平均252mmolCm−2d−1)。这项研究强调了二氧化碳的巨大时空变异性、阶段性洪灾事件的重要性、邻近的改良酸性湿地的作用，以及地下水排放作为二氧化碳来源进入河口的作用。由于缺乏高分辨率数据来捕捉热带和亚热带地区的短期事件(如洪水)，全球对河口二氧化碳气水通量的估计可能被低估。
Dissolved CO2 dynamics associated with flooding and postflood recovery were investigated in the lower estuary of the Richmond River and a tributary draining an acidic wetland. Heavy rains (up to 133 mm d−1) resulted in large discharge volumes (up to 250 × 106 m3 d−1) flushing the estuary in less than a day. Maximum values of the partial pressure of CO2 ( PCO2 , 2006 Pa or 19,801 μatm) occurred during the postflood recovery period. High PCO2 values were related to the transport of floodplain metabolic products via surface runoff and groundwater as well as the low pH (4.22) of waters draining a modified wetland with coastal acid sulphate soils. Aerobic respiration alone could not explain the high concentrations of CO2 in the estuary and an area of low buffering developed in the 0–20 salinity range. PCO2 was correlated with freshwater discharge in the Richmond River main channel (R2 = 0.82; p 0.05; n = 7). Air‐water fluxes of CO2 were at the high end of the range for aquatic systems (maximum 1413 mmol C m−2 d−1, mean 252 mmol C m−2 d−1). This study highlights the large spatiotemporal variability of PCO2 , the importance of episodic flooding events, the role of adjacent modified acidic wetlands, and the role of groundwater discharge as a source of CO2 to estuaries. Global estimates of CO2 air‐water fluxes in estuaries may be under estimated due to the lack of high‐resolution data to capture short‐term episodic events (e.g., flooding), in tropical and subtropical areas.