Accumulation of recalcitrant dissolved organic matter in aerobic aquatic systems
Abstract An oxygenated atmosphere changed life on Earth but it also provided a negative feedback to organic matter accumulation by increasing decomposition rates. Nonetheless, dissolved organic carbon (DOC) is a huge carbon pool (> 750 Pg) and it can accumulate to high concentrations (20–100 mg C...
| Published in: | Limnology and Oceanography Letters |
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| Main Authors: | , , |
| Other Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Wiley
2022
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1002/lol2.10265 https://onlinelibrary.wiley.com/doi/pdf/10.1002/lol2.10265 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/lol2.10265 https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.1002/lol2.10265 |
| Summary: | Abstract An oxygenated atmosphere changed life on Earth but it also provided a negative feedback to organic matter accumulation by increasing decomposition rates. Nonetheless, dissolved organic carbon (DOC) is a huge carbon pool (> 750 Pg) and it can accumulate to high concentrations (20–100 mg C L −1 ) in some freshwater aquatic systems, yet it is not clear why. Here, we examine DOC in several Greenland lakes with varying DOC concentrations and identify processes that could alter its composition to make it increasingly recalcitrant. Δ 14 C aging of DOC corresponded with increased DOC concentrations, slower degradation rates, changes in isotope ratios and optical properties, all suggesting that photochemical and microbial degradation processes contributed to recalcitrance. Young DOC degradation was stimulated by phosphorus, but older DOC was not, suggesting an important role for nutrients early in degradation. Photochemical processing coupled with decreased habitat diversity in hydrologically isolated systems may enable recalcitrant DOC to accumulate with important implications for Earth's carbon and oxygen cycles. |
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