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Cite this paper: |
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LI Xuegang, SONG Jinming, YUAN Huamao, LI Ning, DUAN Liqin, QU Baoxiao. CO2 flux and seasonal variability in the turbidity maximum zone and surrounding area in the Changjiang River estuary[J]. Journal of Oceanology and Limnology, 2015, 33(1): 222-232 |
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CO2 flux and seasonal variability in the turbidity maximum zone and surrounding area in the Changjiang River estuary |
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| LI Xuegang, SONG Jinming, YUAN Huamao, LI Ning, DUAN Liqin, QU Baoxiao |
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| Institute of Oceanography, Chinese Academy of Sciences, Qingdao 266071, China |
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| Abstract: |
| The turbidity maximum zone (TMZ) is one of the most important regions in an estuary. However, the high concentration of suspended material makes it difficult to measure the partial pressure of CO2 (p CO 2) in these regions. Therefore, very little data is available on the p CO2 levels in TMZs. To relatively accurately evaluate the CO2 flux in an example estuary, we studied the TMZ and surrounding area in the Changjiang (Yangtze) River estuary. From seasonal cruises during February, August, November 2010, and May 2012, the p CO2 in the TMZ and surrounding area was calculated from pH and total alkalinity (TA) measured in situ, from which the CO2 flux was calculated. Overall, the TMZ and surrounding area acted as a source of atmosphere CO2 in February and November, and as a sink in May and August. The average FCO2 was -9, -16, 5, and 5 mmol/(m2 ·d) in May, August, November, and February, respectively. The TMZ's role as a source or sink of atmosphere CO2 was quite different to the outer estuary. In the TMZ and surrounding area, suspended matter, phytoplankton, and pH were the main factors controlling the FCO2, but here the influence of temperature, salinity, and total alkalinity on the FCO2 was weak. Organic carbon decomposition in suspended matter was the main reason for the region acting as a CO2 source in winter, and phytoplankton production was the main reason the region was a CO2 sink in summer. |
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| Key words:
CO2 flux|seasonal variability|turbidity maximum zone|Changjiang River estuary
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| Received: 2013-11-11 Revised: 2014-03-04 |
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