EGU24-846, updated on 08 Mar 2024
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Data deficient saltmarsh species has climate relevant carbon stocks from the east coast of India

Sandip Kumar Mohakud, Amrit Kumar Mishra, and Syed Hilal Farooq
Sandip Kumar Mohakud et al.
  • Indian Institute of Technology Bhubaneswar, Indian Institute of Technology Bhubaneswar, School of Earth, Ocean and Climate Sciences, Bhubaneswar, India (

The saltmarsh ecosystems of India are least studied,  despite being considered as nature-based solutions (NbS) towards climate change mitigation. This study quantifies the seasonal variation in carbon stocks of mono-specific saltmarsh specie (Porteresia coarctata) and its potential to play an important role in India’s climate change mitigation plans. Seasonal (pre-and post-monsoon) sampling of P. coarctata surface water, biomass and 30 cm sediment core was collected across four estuarine locations on the east coast of India to quantify the sediment dry bulk density (DBD), organic matter (OM%), organic carbon (Corg%), Corg stocks of sediment and biomass, total carbon (C%) and nitrogen (N%) and stable isotope ratios of Carbon (δ13C) and Nitrogen (δ15N).  In general, the sediment DBD, OM and Corg of P. coarctata meadows was higher in post-monsoon and was influenced by salinity and pH changes. Carbon isotope ratio (δ13C) of sediment C sources suggested, particulate organic matter (POM) contribution was highest (0.04-0.79%) followed by P. coarctata (0.01–052%) and other macrophytes across our study locations.  The seasonal variation of δ13C showed increased contribution of marine derived particulate and dissolved organic matter into P. coarctata meadows in post-monsoon season.  Higher δ15N values observed in post-monsoon season suggest an anthropogenic input, that was utilized by P. coarctata to increase its above and below-ground biomass and shoot density. The combined ecosystem (30 cm sediment + biomass) Corg stocks of P. coarctata was 1.7-fold higher in post-monsoon (4021.20± 917 Mg C) compared to pre-monsoon (2297.36 ±647 Mg C) season among the four locations with a sediment Corg contribution >70%. Based on the International Panel for Climate Change Tier II assessment the P. coarctata meadows (443 ha) can help in avoiding the pre-and post-monsoon emissions of 8431.34 and 14757.84 Mg CO2, respectively. The combined price of the total CO2 equivalent stored in P. coarctata meadows in pre- and post-monsoon is calculated to be US$ 14.50 and US$ 25.38 million, respectively. Further studies quantifying the NbS potential of mono-specific and mixed P. coarctata meadows along the coast of India is important, along with the integration of saltmarsh ecosystems into India’s National Action Plan on Climate Change.

Keywords: Saltmarsh, Carbon stocks, Porterasia coarctata, Nature-based solution, Stable isotopes

How to cite: Mohakud, S. K., Mishra, A. K., and Farooq, S. H.: Data deficient saltmarsh species has climate relevant carbon stocks from the east coast of India, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-846,, 2024.