Journal of East China Normal University(Natural Science) ›› 2024, Vol. 2024 ›› Issue (1): 104-112.doi: 10.3969/j.issn.1000-5641.2024.01.011

• Ecological Security of Estuarine and Coastal • Previous Articles     Next Articles

Temperature adaptability of dark carbon fixation in seawater fromthe Yangtze River Estuary

Jiaming CHEN, Shiming WANG, Rongrong YANG, Ziyan CHEN, Xia LIANG*(), Lijun HOU   

  1. State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
  • Received:2023-02-16 Accepted:2023-04-06 Online:2024-01-25 Published:2024-01-23
  • Contact: Xia LIANG E-mail:xliang@sklec.ecnu.edu.cn

Abstract:

To clarify the effects of global warming on dark carbon fixation (DCF) in eutrophic estuaries, the rates of total DCF and DCF driven by ammonia-oxidizing microorganisms (DCFAOB) were studied under various water temperatures and nitrogen concentrations using 14C labeling (NaH14CO3) and the allylthiourea (ATU) inhibitor method. The Yangtze River Estuary was used as a study area and sampling locations were set up in the estuary and offshore locations. The DCF rates in the Yangtze River Estuary ranged from 0.23 to 0.33 μmolC·L–1·d–1 and that DCFAOB rates accounted for 4.13% to 43.61% of the DCF. Although DCF rates increase significantly under optimum temperatures, the increase was more obvious with changes in ambient temperature under low salinity. The optimum temperatures for DCF in areas of low and high salinity were found to be 30℃ and 25℃, respectively, with the addition of ammonia-nitrogen at these conditions significantly increasing the DCF rates. The results of this study reveal how dark carbon fixation in estuarine water can change when subjected to environmental temperature changes, thereby providing theoretical support and data references to aid in the comprehensive understanding and scientific assessment of carbon fixation and carbon sink flux in estuarine ecosystems.

Key words: dark carbon fixation, the Yangtze River Estuary, ammonia-oxidizing microorganisms, salinity

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