Coupled micrometeorological and biological processes on atmospheric CO 2 concentrations at the land–ocean boundary, NE coast of India

• Published in: Atmospheric environment (1994) Vol. 45; no. 23; pp. 3903 - 3910
• Main Authors: Ganguly, D., Dey, M., Chowdhury, C., Pattnaik, A.A., Sahu, B.K., Jana, T.K.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2011
• Subjects: Atmospheric CO 2; Coastal water; Heterotrophy; Micrometeorological forcing; Heterotrophy; Micrometeorological forcing; Coastal water; Atmospheric CO 2
• ISSN: 1352-2310; 1873-2844
• DOI: 10.1016/j.atmosenv.2010.08.047

This study reveals that land–sea breezes, atmospheric stability and influence of net ecosystem metabolism for the conversion of organic carbon to atmospheric CO 2 are the major driving forces behind the variation of atmospheric CO 2 at the land–ocean boundary, northeast coast of India. The seasonal variation of partial pressure of CO 2 (pCO 2) and its efflux from the coastal water were several fold higher in the pre-monsoon (1807.9 ± 757.03 μ atm; 579.03 ± 172.9 μM m −2 h −1) than in the monsoon (1070.5 ± 328.5 μ atm; 258.96 ± 185.65 μM m −2 h −1) and the post-monsoon (615.7 ± 121.6 μ atm; 53.27 ± 19.24 μM m −2 h −1). The mean photic zone productivity to column respiration ratio was 0.12 ± 0.08, revealing predominance of heterotrophic processes. Community respiration was at minimum during monsoon (38.82 ± 8.63 mM C m −2 d −1) but was at maximum (173.8 ± 111.8 mM C m −2 d −1) during pre-monsoon and intermittent (125.07 ± 11.97 mM C m −2 d −1) during post-monsoon. Diurnal variations of atmospheric CO 2 concentration were determined by local air circulations and atmospheric stability. Seasonal variations of atmospheric CO 2 bear a significant signature of biological processes occurring in the coastal water by means of air–sea exchange, markedly affected by the net ecosystem metabolism. Important predictors of coastal atmospheric CO 2 in decreasing order of explained variability are wind direction, stability, CO 2 efflux and wind velocity.