Open AccessPhotomineralization of organic carbon in a eutrophic, semiarid estuary
Author(s) -
Wang Hongjie,
Hu Xinping,
Wetz Michael S.,
Hayes Kenneth C.,
Lu Kaijun
Publication year - 2020
Publication title -
limnology and oceanography letters
Language(s) - English
Resource type - Journals
ISSN - 2378-2242
DOI - 10.1002/lol2.10146
Subject(s) - dissolved organic carbon , carbon cycle , estuary , environmental chemistry , phytoplankton , bay , eutrophication , total organic carbon , carbon fibers , chemistry , chlorophyll a , environmental science , lability , total inorganic carbon , plankton , oceanography , carbon dioxide , ecology , ecosystem , nutrient , biology , geology , biochemistry , materials science , organic chemistry , composite number , composite material
The 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 μ M 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 (δ 13 C∼ −18.6‰) of degraded DOC, as calculated using the DIC “Keeling” plot, further indicated high photochemical lability of 13 C‐enriched DOC in this semiarid environment. Our finding showed that photomineralization of 13 C‐enriched DOC is an important component of carbon cycle in this system, and this process does not necessarily remove 13 C‐depleted organic carbon as observed in other coastal systems.