Friday, November 29, 2013

New paper finds the South China Sea is a net source of CO2 to the atmosphere

A paper published today in Biogeosciences finds the South China Sea is a net annual source of CO2 to the atmosphere. The findings oppose the commonly held assumption that oceans serve as a net sink for CO2, and add to several other recent peer-reviewed papers finding the oceans can act as net annual sources of CO2, and which demonstrate many prior assumptions of the global carbon cycle may be highly erroneous. 

Based upon 14 field surveys conducted between 2003-2008, the authors find "The estimate of annual sea–air CO2 fluxes showed that most areas of the South China Sea proper served as weak to moderate sources of the atmospheric CO2." " Overall the four [regions of the South China Sea] contributed (18 ± 10) × 1012 g C yr−1 to the atmospheric CO2."

Biogeosciences, 10, 7775-7791, 2013

Author(s): W.-D. Zhai, M.-H. Dai, B.-S. Chen, X.-H. Guo, Q. Li, S.-L. Shang, C.-Y. Zhang, W.-J. Cai, and D.-X. Wang

Based upon 14 field surveys conducted between 2003 and 2008, we showed that the seasonal pattern of sea surface partial pressure of CO2 (pCO2) and sea–air CO2 fluxes differed among four different physical–biogeochemical domains in the South China Sea (SCS) proper. The four domains were located between 7 and 23° N and 110 and 121° E, covering a surface area of 1344 × 103 km2 and accounting for ~ 54% of the SCS proper. In the area off the Pearl River estuary, relatively low pCO2 values of 320 to 390 μatm were observed in all four seasons and both the biological productivity and CO2 uptake were enhanced in summer in the Pearl River plume waters. In the northern SCS slope/basin area, a typical seasonal cycle of relatively high pCO2 in the warm seasons and relatively low pCO2 in the cold seasons was revealed. In the central/southern SCS area, moderately high sea surface pCO2 values of 360 to 425 μatm were observed throughout the year. In the area west of the Luzon Strait, a major exchange pathway between the SCS and the Pacific Ocean, pCO2 was particularly dynamic in winter, when northeast monsoon induced upwelling events and strong outgassing of CO2. These episodic events might have dominated the annual sea–air CO2 flux in this particular area. The estimate of annual sea–air CO2 fluxes showed that most areas of the SCS proper served as weak to moderate sources of the atmospheric CO2, with sea–air CO2 flux values of 0.46 ± 0.43 mol m−2 yr−1 in the northern SCS slope/basin, 1.37 ± 0.55 mol m−2 yr−1 in the central/southern SCS, and 1.21 ± 1.48 mol m−2 yr−1 in the area west of the Luzon Strait. However, the annual sea–air CO2exchange was nearly in equilibrium (−0.44 ± 0.65 mol m−2 yr−1) in the area off the Pearl River estuary. Overall the four domains contributed (18 ± 10) × 1012 g C yr−1 to the atmospheric CO2.

Related: Another paper published today also finding erroneous assumptions of the global carbon cycle; ocean outgassing of CO2 greater than previously believed

Related posts demonstrating significant erroneous assumptions about the global carbon cycle:

New paper finds another huge error in carbon cycle assumptions equivalent to 30 years of man-made emissions

New paper finds the oceans are a net source of CO2 to the atmosphere

New paper finds ocean along N. California coast is a net source of CO2 to the atmosphere

New paper finds ocean along Baja California coast is a net source of CO2 to the atmosphere

New paper finds the oceans are a net source of CO2

New paper finds global carbon cycle datasets may be biased

New paper finds grasslands are a net source of CO2 to the atmosphere

New paper finds rice crops are a net source of CO2 to the atmosphere

New paper finds hay, oats, canola crops are net sources of CO2 to the atmosphere

New paper finds sugarcane plantation is a net source of CO2 to the atmosphere

New paper finds Mediterranean cover crops are a net source of CO2 to the atmosphere

Paper finds rice paddy fields are a net source of CO2 to the atmosphere

New paper finds another problem with global carbon-cycle models: plant respiration is 'as different as night and day'

2 comments:

  1. Humlum et al have shown that the source of recent increases in atmospheric CO2 are the southern tropical oceans. Apparently the tropical oceans in the northern hemisphere also add to atmospherical CO2. The colder oceans at higher latitudes should serve as a CO2 sink. the temperature dependence of the CO2 solubility in sea water should be the driving force,

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  2. Time for a reminder:

    http://www.newclimatemodel.com/evidence-that-oceans-not-man-control-co2-emissions/

    which shows all the primary sources as sun warmed ocean surfaces including the South China Sea.

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