Contribution of seagrass blue carbon toward carbon neutral policies in a touristic and environmentally-friendly island

Estimates of organic carbon (Corg) storage by seagrass meadows which consider inter-habitat variability are essential to understand their potential to sequester carbon dioxide (CO2) and derive robust global and regional estimates of blue carbon storage. In this study, we provide baseline estimates of seagrass extent, and soil Corg stocks and accumulation rates from different seagrass habitats at Rottnest Island (in Amphibolis spp., Posidonia spp., Halophila ovalis, and mixed Posidonia/Amphibolis spp. meadows). The Corg stocks in 0.5 m thick seagrass soil deposits, derived from 24 cores, were 5.1 ± 0.7 kg Corg m–2 (mean ± SE, ranging from 0.05 to 12.9 kg Corg m–2), accumulating at 23.2 ± 3.2 g Corg m–2 year–1 (ranging from 0.22 to 58.9 g Corg m–2 year–1) over the last decades. There were significant differences in Corg content (%) and stocks (mg Corg cm–3), stable carbon isotope composition of the soil organic matter (δ13C), and soil grain size among the seagrass meadows studied, highlighting that biotic and abiotic factors influence seagrass soil Corg storage. Mixed meadows of Posidonia/Amphibolis spp. and monospecific meadows of Posidonia spp. and Amphibolis spp. had the highest Corg stocks (ranging from 6.2 to 6.4 kg Corg m–2), while Halophila spp. meadows had the lowest Corg stocks (1.2 ± 0.6 kg Corg m–2). We estimated a total soil Corg stock of 48.1 ± 8.5 Gg Corg beneath the 755 ha of Rottnest Island’s seagrasses, and a Corg sequestration capacity of 0.81 ± 0.06 Gg Corg year–1, which is equivalent to the sequestration of ∼22% of the island’s current annual CO2 emissions. Our results contribute to the existing global dataset on seagrass soil Corg storage and show a significant potential of seagrass to sequester CO2, which are particularly relevant in the context of achieving carbon neutrality through conservation actions in environmentally-marketed, tourist destinations such as Rottnest Island

Australian vegetated coastal ecosystems as global hotspots for climate change mitigation

Unidad de excelencia María de Maeztu MdM-2015-0552Policies aiming to preserve vegetated coastal ecosystems (VCE; tidal marshes, mangroves and seagrasses) to mitigate greenhouse gas emissions require national assessments of blue carbon resources. Here, we present organic carbon (C) storage in VCE across Australian climate regions and estimate potential annual CO emission benefits of VCE conservation and restoration. Australia contributes 5-11% of the C stored in VCE globally (70-185 Tg C in aboveground biomass, and 1,055-1,540 Tg C in the upper 1 m of soils). Potential CO emissions from current VCE losses are estimated at 2.1-3.1 Tg CO-e yr, increasing annual CO emissions from land use change in Australia by 12-21%. This assessment, the most comprehensive for any nation to-date, demonstrates the potential of conservation and restoration of VCE to underpin national policy development for reducing greenhouse gas emissions

Australian vegetated coastal ecosystems as global hotspots for climate change mitigation

© 2019, The Author(s). Policies aiming to preserve vegetated coastal ecosystems (VCE; tidal marshes, mangroves and seagrasses) to mitigate greenhouse gas emissions require national assessments of blue carbon resources. Here, we present organic carbon (C) storage in VCE across Australian climate regions and estimate potential annual CO2 emission benefits of VCE conservation and restoration. Australia contributes 5–11% of the C stored in VCE globally (70–185 Tg C in aboveground biomass, and 1,055–1,540 Tg C in the upper 1 m of soils). Potential CO2 emissions from current VCE losses are estimated at 2.1–3.1 Tg CO2-e yr-1, increasing annual CO2 emissions from land use change in Australia by 12–21%. This assessment, the most comprehensive for any nation to-date, demonstrates the potential of conservation and restoration of VCE to underpin national policy development for reducing greenhouse gas emissions

Australian vegetated coastal ecosystems as global hotspots for climate change mitigation

Policies aiming to preserve vegetated coastal ecosystems (VCE; tidal marshes, mangroves and seagrasses) to mitigate greenhouse gas emissions require national assessments of blue carbon resources. Here, we present organic carbon (C) storage in VCE across Australian climate regions and estimate potential annual CO2 emission benefits of VCE conservation and restoration. Australia contributes 5-11% of the C stored in VCE globally (70-185 Tg C in aboveground biomass, and 1,055-1,540 Tg C in the upper 1 m of soils). Potential CO2 emissions from current VCE losses are estimated at 2.1-3.1 Tg CO2-e yr-1, increasing annual CO2 emissions from land use change in Australia by 12-21%. This assessment, the most comprehensive for any nation to-date, demonstrates the potential of conservation and restoration of VCE to underpin national policy development for reducing greenhouse gas emissions

Australian vegetated coastal ecosystems as global hotspots for climate change mitigation

Policies aiming to preserve vegetated coastal ecosystems (VCE; tidal marshes, mangroves and seagrasses) to mitigate greenhouse gas emissions require national assessments of blue carbon resources. Here, we present organic carbon (C) storage in VCE across Australian climate regions and estimate potential annual CO emission benefits of VCE conservation and restoration. Australia contributes 5-11% of the C stored in VCE globally (70-185 Tg C in aboveground biomass, and 1,055-1,540 Tg C in the upper 1 m of soils). Potential CO emissions from current VCE losses are estimated at 2.1-3.1 Tg CO-e yr, increasing annual CO emissions from land use change in Australia by 12-21%. This assessment, the most comprehensive for any nation to-date, demonstrates the potential of conservation and restoration of VCE to underpin national policy development for reducing greenhouse gas emissions

Australian vegetated coastal ecosystems as global hotspots for climate change mitigation

Unidad de excelencia María de Maeztu MdM-2015-0552Policies aiming to preserve vegetated coastal ecosystems (VCE; tidal marshes, mangroves and seagrasses) to mitigate greenhouse gas emissions require national assessments of blue carbon resources. Here, we present organic carbon (C) storage in VCE across Australian climate regions and estimate potential annual CO emission benefits of VCE conservation and restoration. Australia contributes 5-11% of the C stored in VCE globally (70-185 Tg C in aboveground biomass, and 1,055-1,540 Tg C in the upper 1 m of soils). Potential CO emissions from current VCE losses are estimated at 2.1-3.1 Tg CO-e yr, increasing annual CO emissions from land use change in Australia by 12-21%. This assessment, the most comprehensive for any nation to-date, demonstrates the potential of conservation and restoration of VCE to underpin national policy development for reducing greenhouse gas emissions