Tracing Alterations in Carbon Sink Estimates
The Project
Blue carbon ecosystems provide an essential support system for climate change adaptation along the coastline globally by sequestering significant amounts of carbon from the atmosphere and ocean. The study was envisaged as a step forward towards understanding the sources of carbon through various state-of art advanced analytical instruments and field measurements. Sediment transport modelling was carried out to estimate the partitioning of organic carbon between the mangrove ecosystem and the coast. Model predictions provided scenarios of sediment accumulation/ erosion and corresponding C gain/loss along the coast. Field measurements were corroborated with remote sensing methods to determine ecosystem-wise carbon sequestration rates and C-stocks. Improved sensor resolution and the availability of additional spectral bands with images of satellite sensors provided opportunities to characterize mangrove ecosystems to the level of communities/species that provided a baseline data on the spatial extent of mangrove zonation its sustainable management.
Carbon apportionment in different segments of a mangrove ecosystem
Realtime monitoring of GHG fluxes established at
Bhitarkanika National Park, Odisha
Aim
Determine the role of coastal vegetative ecosystems in carbon sequestration through biogeochemical measurements, geo-spatial assessments and modelling predictions.
Rationale
Considering the increased recognition coastal vegetative ecosystem as prominent C sinks, the study intended to depict their role in climate change mitigation to achieve India’s Intended Nationally Determined Contribution #5 (INDC goals), as India has already committed to create an additional sink of 2.5-3 billion tonnes of CO2 equivalent.
Objectives
Key Findings
Carbon apportionment in the biomass of seagrass ecosystem
Higher dry root biomass and the difference in the shoot/root ratio indicates the efficient transfer of photosynthetically fixed carbon in the below ground biomass (BGB). This biomass fraction of the seagrass ecosystem can remain buried for centuries to millennia, making them a potential CO2 sink..
Mitigation scenarios: Significance of conservation and restoration of coastal vegetative ecosystem
| Carbon sequestration in coastal ecosystems | Mangrove | Seagrass |
|---|---|---|
| Net C accrual per hectare per year | 1.69 Mg | 1.66 Mg |
| Additional CO2 sink by increasing 20% area cover per year | ~669 Gg | ~84.4 Gg |
| Restoration of 100 ha of stressed/ degraded ecosystem will reduce CO2 emissions per year by | 144 Gg | 52.2 Gg |
One of the key targets as mandated in India’s INDC, is to create an additional carbon sink of 2.5 to 3 billion tonnes of CO2 equivalent through additional forest and tree cover by 2030. In this context, the conservation and restoration of coastal vegetative ecosystem plays a vital role with respect to their high carbon sequestration rates.
Example of sediment transport and apportionment between mangrove and the coast from Godavari Estuary
The load of the sediment has moved from the Godavari estuary to coastal waters due to the strong riverine currents, and also capable to carry in the open ocean. Riverine currents are carrying the large portion of high turbidity and sediment rich water to the offshore regions The model predicted high sediment load at the Bhairavapalem mouth, close to the mangrove areas..
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