Wang, HongjieHu, XinpingWetz, Michael S.Hayes, Kenneth C.Lu, Kaijun2021-05-192021-05-192020-01-28Wang, H., X. Hu, M.S. Wetz, K.C. Hayes, and K. Lu. 2020. Photomineralization of organic carbon in a eutrophic, semiarid estuary. Limnology and Oceanography Letters 5: 246-253https://hdl.handle.net/1969.6/89590The effect of photomineralization on the carbon cycle in a eutrophic, semiarid estuary (Baffin Bay, Texas) was investigated using closed-system incubations. Photochemical production rate of dissolved inorganic carbon ranged from 0.16 to 0.68 μM hr−1, with a daily removal of 0.3∼1.5% of the standing stock of dissolved organic carbon (DOC). The photomineralization rate was negatively correlated with chlorophyll a concentration, suggesting that plankton-derived DOC was less photoreactive to solar radiation. The stable carbon isotope composition (δ13C∼ −18.6‰) of degraded DOC, as calculated using the DIC “Keeling” plot, further indicated high photochemical lability of 13C-enriched DOC in this semiarid environment. Our finding showed that photomineralization of 13C-enriched DOC is an important component of carbon cycle in this system, and this process does not necessarily remove 13C-depleted organic carbon as observed in other coastal systems.Articlehttps://doi.org/10.1002/lol2.10146