Salt Marsh: Ecologically Important, Yet Least Studied Blue Carbon Ecosystems in India

Abstract

Salt marshes are intertidal halophytic vegetations, distributed in mid to lower latitudes. They provide important ecosystem services, including transportation and remineralization of nutrients, habitat for coastal biota, coastal bioshield, biofilters and recreation and cultural benefits. In India, 15 salt marsh species so far have been reported, spread over 1600 km 2 . Salt marshes are known to adapt themselves to the changing environmental conditions fairly quickly by maintaining a balance between the existing pressures and the prevailing state. Thus, they tend to retain a long-term ecosystem sustainability under changing environmental conditions. Recent studies have recognized them for their extraordinary capacity of carbon sequestration, which gives them edge amongst the coastal ecosystems, but the carbon stock is comparatively low due to their alarming decline in global areal extent.In the Indian context, salt marshes occupy a significant share of the coastline along with the other blue carbon ecosystems like mangroves and seagrasses. This provides India with a very promising alternative for achieving its Intended Nationally Determined Contribution towards climate change mitigation through enhancing additional carbon sinks (INDC goal # 5). But, despite its rich salt marsh diversity and distribution along the entire coastline, Indian salt marshes are one of the most overlooked coastal ecosystems. The documented studies on the Indian marshes are relatively scarce and studies addressing their carbon storage and climate change mitigation potential are totally non-existent. There is an urgent need for targeted scientific studies to be taken up on the Indian salt marsh ecosystems to develop a holistic and updated database, which can support resource management, decisionmaking and facilitate to estimate Blue carbon economy of India.

Aquatic and edaphic determinants influencing carbon storage in a salt marsh grass, Porteresia coarctata, of the Bhitarkanika wildlife sanctuary and the Mahanadi estuary

“…Higher bulk density at Mahanadi may be the possible reason for insignificant relationship of sand, silt, and clay at Mahanadi, whereas in case of Bhitarkanika, there is a significant positive relationship with silt and clay (P < 0.01) and a significant negative relationship with sand (P < 0.05). The results of our study are consistent with the previous studies that suggest a significant role of various aquatic and edaphic factors in governing the growth, biomass and carbon storage capability of the species (Banerjee et al, 2017;Crain et al, 2004;Jana et al, 2013;Odum, 1988;Watson & Byren, 2009).…”

“…This variation of sustenance of P. coarctata in the Bhitarkanika and Mahanadi mangrove ecosystems with a soil EC ranging from 2.15 ± 0.22 mScm −1 to 17.21 ± 2.92 mScm −1 has also been proved by Banerjee et al. (2017) and Jana et al. (2013).…”

“…In case of the Mahanadi mangrove ecosystem, the highest value is recorded at Stn.1, which is also a moderately saline environment more or less similar to the water salinity value at Stn.3 in Bhitarkanika (Exhibit 3b). This variation of sustenance of P. coarctata in the Bhitarkanika and Mahanadi mangrove ecosystems with a soil EC ranging from 2.15 ± 0.22 mScm −1 to 17.21 ± 2.92 mScm −1 has also been proved by Banerjee et al (2017) and Jana et al (2013). Seasonal increase of AGB (Mg ha −1 ) plotted for P. coarctata showed higher values for the Bhitarkanika mangrove ecosystem in comparison with the Mahanadi mangrove ecosystem (Exhibit 4).…”

Soil degradation and mitigation in agricultural lands in the Indian Anthropocene

“…Mangroves, salt marshes, seagrass meadows, and coral reefs occupy the major coastal habitats in India (Ragavan et al, 2020). Of these, mangrove and coral reefs have been much studied for their ecology and biodiversity (Banerjee et al, 2017). The Sundarbans mangroves belong floristically to the Indo‐Andaman mangrove province within the species‐rich Indo‐West Pacific group.…”

Movement of Microphytobenthos and Sediment Between Mudflats and Salt Marsh During Spring Tides

“…Salt marshes provide a range of ecosystem functions, such as denitrification and nutrient biogeochemistry (Seitzinger, 1973;Ogilvie et al, 1997;Underwood, 1997;Cibic et al, 2007), primary production and carbon storage (Macreadie et al, 2013;Mueller et al, 2019), wave attenuation and coastal protection (Shepard et al, 2011;Yang et al, 2012), food provisioning (Grothues and Able, 2003;Banerjee et al, 2017), and cultural benefits that are important ecosystem services for human society. There has been significant research into how to protect, enhance, and restore salt marshes to preserve these functions in the face of changing environmental pressures on coasts (Reed et al, 2018).…”