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Isotope Constraints on the Sources of Particulate Organic Carbon in a Subtropical Deep Reservoir
Author(s) -
Zheng LiWei,
Li Dawei,
Ding Xiaodong,
Lee TsungYu,
Zheng Zhenzhen,
Shiah FuhKwo,
Zheng Xufeng,
Hsu TingChang,
Huang JrChuan,
Kao ShuhJi
Publication year - 2020
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1029/2019jg005240
Subject(s) - carbon cycle , total organic carbon , isotopes of carbon , environmental science , sink (geography) , subtropics , stable isotope ratio , flux (metallurgy) , carbon sink , environmental chemistry , particulates , carbon dioxide , deposition (geology) , carbon flux , carbon fibers , geology , oceanography , chemistry , sediment , ecology , climate change , paleontology , ecosystem , materials science , geography , composite number , composite material , biology , quantum mechanics , physics , cartography , organic chemistry
Reservoirs are active sites in the terrestrial environment in terms of carbon transformation and storage. Continuous reservoir construction reinforces the importance of such artificial storage; however, knowledge pertaining to the sources, cycling, and preservation of autochthonous/allochthonous particulate organic carbon (POC) in reservoirs remains incomplete. We monitored the flux and carbon isotope composition of sinking particles in a subtropical deep reservoir, and the results were compared with the isotopic signatures of potential POC sources (soil) and the sedimentary sink. We found that the typhoon‐induced POC flux was transported laterally at intermediate water depths within the reservoir and that it contributed more than 70% of the annual deposition. An isotope ternary mixing model showed that over 87% of the POC preserved in sediments was allochthonous. Although the autochthonous POC from primary production was preferentially degraded, the preserved autochthonous POC (42 ± 14 gC m −2 yr −1 ) was comparable to the observed carbon dioxide uptake (35 gC m −2 yr −1 ) by the reservoir, suggesting a high efficiency of carbon preservation in subtropical deep reservoirs.