Photomineralization of organic carbon in a eutrophic, semiarid estuary

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 μM hr−1, with a daily removal of 0.3∼1.5% of the standing...

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Bibliographic Details
Published in:Limnology and oceanography letters 2020-06, Vol.5 (3), p.246-253
Main Authors: Wang, Hongjie, Hu, Xinping, Wetz, Michael S., Hayes, Kenneth C., Lu, Kaijun
Format: Article
Language:English
Subjects:
Carbon
Carbon cycle
Carbon isotopes
Chlorophyll
Coasts
Dissolved inorganic carbon
Dissolved organic carbon
Estuaries
Eutrophication
Experiments
Hypotheses
Lignin
Oceanography
Phenols
Photochemicals
Plankton
Pore size
Rivers
Semiarid environments
Solar radiation
Water temperature
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Summary: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 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.
ISSN:2378-2242
2378-2242
DOI:10.1002/lol2.10146