Research article - Peer-reviewed, 2021
Synchronous evaporation and aquatic primary production in tropical river networksZhong, Jun; Wallin, Marcus B.; Wang, Wanfa; Li, Si-Liang; Guo, Laodong; Dong, Kejun; Ellam, Rob M.; Liu, Cong-Qiang; Xu, Sheng
AbstractRivers play an important role in global water and carbon cycling, but there are still large uncertainties concerning evaporation and aquatic photosynthesis. Here we combined measurements of water chemistry, isotopic compositions (i.e., delta D-w, delta O-18(W), delta C-13(DIC) and Delta C-14(DIC)) and geographic characteristics (i.e., river width) to elucidate in-stream hydrological and biogeochemical processes across rivers in Hainan Island, China. The results showed that dissolved inorganic carbon (DIC) in river waters was largely of modern origin, with about 95% from contemporary biogenic sources based on an isotopic mass balance of Delta C-14(DIC). Significant evaporation and aquatic primary production co-occurred in these tropical rivers with large amounts of water and DIC being rapidly turned over in the water column, altering the water cycle and the carbon balance. High rates of evaporation and aquatic primary production were observed in the headwater segments, with narrow river width but broad available reactive surface area at the airwater interface. The asymmetric aquatic photosynthesis at different river segments caused the spatial heterogeneities of dissolved solutes. The results suggest that the available reactive area at the water-air interface is responsible for synchronous water loss and dissolved carbon evolution in flat tropical rivers. This study provides evidence that intense evaporation and aquatic photosynthesis mainly occurred in headwater segments, which has implications for understanding global carbon cycling. (C) 2021 Elsevier Ltd. All rights reserved.
KeywordsCarbon cycling; Aquatic photosynthesis; Evaporation; Tropical Rivers; Headwaters
Published inWater Research
2021, volume: 200, article number: 117272
Publisher: PERGAMON-ELSEVIER SCIENCE LTD
Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment
University of Wisconsin Milwaukee
Ellam, Rob M.
University of Glasgow
UKÄ Subject classification
Oceanography, Hydrology, Water Resources
URI (permanent link to this page)