Heavy Metal Pollution in the Ganga River Enhances Carbon Storage Relative to Flux
This study evaluated the relationships between metal pollution and carbon production at six sites along a 285 km length of the Ganga River. Metal contaminated sites did show a significant reduction in microbial biomass, substrate induced respiration, fluorescein diacetate hydrolytic assay (FDAase) and β-d-glucosidase. Concordantly, despite a high concentration of total organic carbon at these sites, CO2 emission at the land–water interface remained low. We found a strong positive correlation between CO2 emission and TOC (r = 0.92; p < 0.001). However, this relationship weakens when the sum of total heavy metal (∑THM) exceed 400 µg g−1. Also, CO2 emission did show a positive correlation (r = 0.85; p < 0.001) with FDAase. The study shows that metal accumulation in riverbed sediment could potentially lead to better carbon sequestration on account of reduced microbial/enzyme activities. This carries significance for riverine carbon budget and modeling.
KeywordsCO2 emission FDAase Ganga River Heavy metal Land–water interface
This research was funded by National Academy of Science (India) (NAS/2012/2/2015-16) as a fellowship to KV and Council of Scientific and Industrial Research, New Delhi (09/013(0611)/2015-EMR-I) as a Fellowship to ES. The authors thank Co-ordinators CAS and DST-FIST, Banaras Hindu University for facilities.
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