Carbon sequestration effects of particulate organic carbon released during macroalgae growth.Credit: Li Hongmei
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Carbon sequestration effects of particulate organic carbon released during macroalgae growth.Credit: Li Hongmei
Macroalgae are the most productive plants in coastal ecosystems. These have attracted worldwide interest due to their ability to sequester carbon. Macroalgal growth can generate large amounts of particulate organic carbon (POC), but it is unclear how these POC are metabolized and how they affect carbon sequestration.
Researchers from the Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, revealed the fate of POC released by macroalgae and its influence on carbon sequestration.
Their results are published in environmental science and technology.
A study on macroalgae blooms of Ulva in the Southern Yellow Sea, China, revealed that POC concentrations in surface seawater increased significantly during blooms.
Subsequently, laboratory simulation experiments revealed that 77.6% of POC was biolabile, and the remaining 22.4% was biorefractory. Microorganisms were observed to convert 23.9% of biolabile POC to dissolved organic carbon (DOC), and a portion of DOC was further converted to biorefractory DOC.
Approximately 39.6% of biorefractory substances remained, including biorefractory POC and biorefractory DOC. Biorefractory POC was more sensitive to photodegradation than biorefractory DOC. The photolytic removal rate of bioresistant POC (14.1%) was more than 10 times that of biorefractory DOC (1.2%).
Finally, 36.3% of the POC released by macroalgae growth could undergo long-term carbon sequestration. This is a neglected carbon sink.
This study provides new insights into the significant carbon sequestration potential of POC released by growing macroalgae, and the proportion of this carbon is considered in the overall carbon sequestration effect provided by macroalgae. It should be.
For more information:
Honmei Li et al. “Particulate organic carbon released during macroalgae growth has important carbon sequestration potential in the ocean” environmental science and technology (2023). DOI: 10.1021/acs.est.3c04959