Export of photolabile and photoprimable dissolved organic carbon from the Connecticut River
Export of photolabile and photoprimable dissolved organic carbon from the Connecticut River
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DOI：
10.1007/s00027-021-00778-8
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发表时间：
2021-02
期刊：
影响因子：
2.4
通讯作者：
B. Yoon;J. Hosen;E. D. Kyzivat;J. Fair;L. Weber;K. Aho;R. Lowenthal;S. Matt;W. V. Sobczak;J. Shanley;Jonathan Morrison;J. Saiers;Aron Stubbins;P. Raymond
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作者：
B. Yoon;J. Hosen;E. D. Kyzivat;J. Fair;L. Weber;K. Aho;R. Lowenthal;S. Matt;W. V. Sobczak;J. Shanley;Jonathan Morrison;J. Saiers;Aron Stubbins;P. Raymond
溶解有机碳（DOC）影响水质，碳循环和水生系统的生态。因此，了解是什么控制DOC是至关重要的，以改善大型模型和最佳管理实践的水生生态系统。DOC转化和去除的两个主要过程，即光化学和微生物DOC降解，协同作用以改变和消除天然沃茨中的DOC。在这里，我们研究了照片和微生物的DOC（光和生物性），和间接的光转化DOC到生物不稳定DOC（biolabile biolability）的样本，捕获的时空和水文梯度的康涅狄格河流域。从这个温带流域输出的DOC的大部分是光不稳定的和光不稳定DOC的浓度与在254 nm处的UV吸光度（r2= 0.86）。DOC的光转化也增加了生物性，总的光不稳定DOC（光不稳定和生物不稳定DOC的总和）显示出较强的相关性，在254 nm处的紫外吸光度（r2= 0.92）。我们估计，高达49%（SD = 3.3%）和10%（SD = 1.1%）的年度DOC出口从康涅狄格河直接光不稳定和可降解，分别。因此，每年有2.82 Gg C year−1（SD = 0.67 Gg C year−1）或1.13 Mg C km− 2 year −1（SD = 0.27 km− 2 year −1）的总光不稳定DOC在河流网络内逃脱光化学降解，从康涅狄格河输出。
Dissolved organic carbon (DOC) impacts water quality, the carbon cycle, and the ecology of aquatic systems. Understanding what controls DOC is therefore critical for improving large-scale models and best management practices for aquatic ecosystems. The two main processes of DOC transformation and removal, photochemical and microbial DOC degradation, work in tandem to modify and remineralize DOC within natural waters. Here, we examined both the photo- and microbial remineralization of DOC (photolability and biolability), and the indirect phototransformation of DOC into biolabile DOC (photoprimed biolability) for samples that capture the spatiotemporal and hydrological gradients of the Connecticut River watershed. The majority of DOC exported from this temperate watershed was photolabile and the concentration of photolabile DOC correlated with UV absorbance at 254 nm (r2= 0.86). Phototransformation of DOC also increased biolability, and the total photolabile DOC (sum of photolabile and photoprimed biolabile DOC) showed a stronger correlation with UV absorbance at 254 nm (r2= 0.92). We estimate that as much as 49% (SD = 3.3%) and 10% (SD = 1.1%) of annual DOC export from the Connecticut River is directly photolabile and photoprimable, respectively. Thus, 2.82 Gg C year−1(SD = 0.67 Gg C year−1) or 1.13 Mg C km−2year−1(SD = 0.27 km−2year−1) of total photolabile DOC escapes photochemical degradation within the river network to be exported from the Connecticut River each year.