Tropical seagrass under range extension provides similar ecosystem services compared to natural meadows

How range extended meadows of seagrasses compare in ecosystem services with existing meadows is less understood. This study reports for the first time the range extension of three tropical seagrass species, i.e., Halophila ovalis , Halodule uninervis and Ruppia maritima from the Asia’s largest brackish water Chilika lagoon into nearby inland areas along the coast of Odisha. Surface water samples, sediment and seagrass biomass of the three species were collected and standard protocols were followed to measure seagrass morphometrics and quantify the sediment carbon (C) and nitrogen (N) stocks. Results indicate high saline conditions favored the establishment of new seagrass meadows. In addition to high salinity, significantly higher sediment N content supported increased growth and morphometrics for the seagrasses except for H. uninervis whose growth was limited due to excessive algal growth. Longer leaves were observed in R. maritima followed by H. uninervis and H. ovalis . The mean sediment C stocks in R. maritima (6.93 ± 2.28 Mg C ha ^− 1 ) was the highest followed by the sediment C stocks of H. ovalis (1.73 ± 0.97 Mg C ha ^− 1 ) and H. uninervis (1.48 ± 0.26 Mg C ha ^− 1 ). The combined CO ₂ storage and climate change mitigation potential of these newly discovered meadows is 111.73-ton CO ₂ per ha with an economic value of US$ 0.009 million. The total N stocks of the three-seagrass meadow was 67.59 ± 4.33 Mg N ha ^− 1 , providing additional co-benefits of nutrient retention. Our study highlights better management and monitoring for seagrass meadows from the coast of Odisha.