Carbon and water cycle coupling at the Kaziranga forest
The carbon flux study carried out at the Kaziranga forest in Assam reveals that the ecosystem releases soil CO2 significantly higher than the other forest ecosystems in India. This characteristic feature probably makes this ecosystem a net carbon source in the atmosphere. Further, a combined analysis of precipitation isotopes and eddy-covariance data reveals that higher plant transpiration rates and productivity are strongly linked during the pre-monsoon season (March to May) but weak in other seasons.
Under the global warming scenario, the study may have concerning implications. Analysis of the rainfall data shows that rainfall in this region has decreased for several decades, especially during the pre-monsoon season. The amount of rain derived from the locally generated moisture, through transpiration, is also experiencing a reducing trend this season. This is especially significant for March-April because this is the time an enhanced hydrological cycle triggers the primary productivity. A reducing trend in rainfall may affect both the ecosystem productivity and the transpiration process. If the plant productivity weakens, it may further affect the carbon sequestration capacity of this fragile ecosystem of northeast India. So over a long-term period, the forest may emit more CO2 into the atmosphere. These studies are published as shown below:
Sarma, D, Deb Burman, P.K., Chakraborty, S., Gogoi, N., Bora, A., Metya, A., Datye, A., Murkute, C., Karipot, K. 2022 Quantifying the net ecosystem exchange at a semi-deciduous forest in northeast India from intra-seasonal to seasonal time scale. Agricul. Forest Meteor. 314 (2022) 108786. https://doi.org/10.1016/j.agrformet.2021.108786
Chakraborty, S., Burman, P.K.D., Sarma, D. et al. 2022 Linkage between precipitation isotopes and biosphere-atmosphere interaction observed in northeast India. npj Clim Atmos Sci 5, 10. https://doi.org/10.1038/s41612-022-00231-z; https://rdcu.be/cH2VG