Blue Carbon & Sequestration

The great barrier reef: A source of CO2 to the atmosphere

Lønborg C, Calleja MLl, Fabricius KE, Smith JN, Achterberg EP. The great barrier reef: A source of CO2 to the atmosphere. Marine Chemistry [Internet]. In Press . Available from: https://www.sciencedirect.com/science/article/pii/S0304420318300471
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $35.95
Type: Journal Article

The Great Barrier Reef (GBR) is the largest contiguous coral reef system in the world. Carbonate chemistry studies and flux quantification within the GBR have largely focused on reef calcification and dissolution, with relatively little work on shelf-scale CO2 dynamics. In this manuscript, we describe the shelf-scale seasonal variability in inorganic carbon and air-sea CO2 fluxes over the main seasons (wet summer, early dry and late dry seasons) in the GBR.

Our large-scale dataset reveals that despite spatial-temporal variations, the GBR as a whole is a net source of CO2 to the atmosphere, with calculated air–sea fluxes varying between −6.19 and 12.17 mmol m−2 d−1 (average ± standard error: 1.44 ± 0.15 mmol m−2 d−1), with the strongest release of CO2occurring during the wet season. The release of CO2 to the atmosphere is likely controlled by mixing of Coral Sea surface water, typically oversaturated in CO2, with the warm shelf waters of the GBR. This leads to oversaturation of the GBR system relative to the atmosphere and a consequent net CO2 release.

Gulf of Mexico estuarine blue carbon stock, extent and flux: Mangroves, marshes, and seagrasses: A North American hotspot

Thorhaug AL, Poulos HM, López-Portillo J, Barr J, Lara-Domínguez ALaura, Ku TC, Berlyn GP. Gulf of Mexico estuarine blue carbon stock, extent and flux: Mangroves, marshes, and seagrasses: A North American hotspot. Science of The Total Environment [Internet]. 2019 ;653:1253 - 1261. Available from: https://www.sciencedirect.com/science/article/pii/S0048969718338816
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $41.95
Type: Journal Article

The Gulf of Mexico blue carbon habitats (mangroves, seagrass, and salt marshes) form an important North American blue carbon hot spot. These habitats cover 2,161,446 ha and grow profusely in estuaries that occupy 38,000 km2 to store substantial sedimentary organic carbon of 480.48 Tg C. New investigations around GoM for Mexican mangroves, Louisiana salt marshes and seagrasses motivated our integration of buried organic carbon to elucidate a new estimate of GoM blue carbon stocks. Factors creating this include: large GoM watersheds enriching carbon slowly flowing through shallow estuarine habitats with long residence times; fewer SE Mexican hurricanes allowing enhanced carbon storage; mangrove carbon productivity enhanced by warm southern basin winter temperatures; large Preservation reserves amongst high anthropogenic development. The dominant total GoM mangrove blue carbon stock 196.88 Tg from total mangrove extent 650,482 ha is highlighted from new Mexican data. Mexican mangrove organic carbon stock is 112.74 Tg (1st sediment meter) plus USA 84.14 Tg. Mexican mangroves vary greatly in storage, total carbon depositional depths and in sediment age (to 3500 y). We report Mexican mangrove's conservative storage fraction for the normally-compared top meter, whereas the full storage depth estimates ranging above 366.78 Tg (high productivity in very deep sediment along the central Veracruz/Tabasco coast) are not reflected in our reported estimates. Seagrasses stock of 184.1 Tg C organic is derived from 972,327 ha areal extent (in 1st meter). The Louisiana marshes form the heart of GoM salt marsh carbon storage 99.5 Tg (in 1st meter), followed by lesser stocks in Florida, Texas, finally Mexico derived from salt marsh extent totaling 650,482 ha. Constraints on the partial estuarine fluxes given for this new data are discussed as well as widespread anthropogenic destruction of the GoM blue carbon. A new North American comparison of our GoM blue carbon stocks versus Atlantic coastal blue carbon stock estimates is presented.

Assessing the carbon and climate benefit of restoring degraded agricultural peat soils to managed wetlands

Hemes KS, Chamberlain SD, Eichelmann E, Anthony T, Valach A, Kasak K, Szutu D, Verfaillie J, Silver WL, Baldocchi DD. Assessing the carbon and climate benefit of restoring degraded agricultural peat soils to managed wetlands. Agricultural and Forest Meteorology [Internet]. 2019 ;268:202 - 214. Available from: https://www.sciencedirect.com/science/article/pii/S0168192319300176
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $19.95
Type: Journal Article

Restoring degraded peat soils presents an attractive, but largely untested, climate change mitigation approach. Drained peat soils used for agriculture can be large greenhouse gas sources. By restoring subsided peat soils to managed, impounded wetlands, significant agricultural emissions are avoided, and soil carbon can be sequestered and protected. Here, we synthesize 36 site-years of continuous carbon dioxide and methane flux data from a mesonetwork of eddy covariance towers in the Sacramento-San Joaquin Delta in California, USA to compute carbon and greenhouse gas budgets for drained agricultural land uses and compare these to restored deltaic wetlands. We found that restored wetlands effectively sequestered carbon and halted soil carbon loss associated with drained agricultural land uses. Depending on the age and disturbance regime of the restored wetland, many land use conversions from agriculture to restored wetland resulted in emission reductions over a 100-year timescale. With a simple model of radiative forcing and atmospheric lifetimes, we showed that restored wetlands do not begin to accrue greenhouse gas benefits until nearly a half century, and become net sinks from the atmosphere after a century. Due to substantial interannual variability and uncertainty about the multi-decadal successional trajectory of managed, restored wetlands, ongoing ecosystem flux measurements are critical for understanding the long-term impacts of wetland restoration for climate change mitigation.

An analysis of the potential positive and negative livelihood impacts of coastal carbon offset projects

Herr D, Blum J, Himes-Cornell A, Sutton-Grier A. An analysis of the potential positive and negative livelihood impacts of coastal carbon offset projects. Journal of Environmental Management [Internet]. 2019 ;235:463 - 479. Available from: https://www.sciencedirect.com/science/article/pii/S0301479719300775
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $41.95
Type: Journal Article

Carbon offset credits, and associated projects, are acclaimed to address economic, environmental and social issues simultaneously. However, critics argue that carbon offset mechanisms are ill equipped to assist developing countries in achieving sustainable development. Social standards now exist to provide robust methods for assessing the social and biodiversity performance of carbon offset projects and credible impact assessments to help ensure positive outcomes for local people and biodiversity. Following such a standard, and simultaneously applying the Sustainable Livelihoods Approach, we develop the Coastal Carbon Impacts Framework (CCIF) as a conceptual framework to document the potential positive and negative impacts of coastal carbon offset projects on local livelihoods. We apply the CCIF to four case studies and derive its main livelihood outcomes as well as describe potential long-term impacts. By using the capitals approach, the CCIF is able to dismantle the different impact areas into smaller entities. This allows a more detailed analysis on the positive and negative impacts a project has on communities – across the natural, financial, social, human, physical, cultural and political capital. While the case studies analysed show mainly positive outcomes, certainly no project is without risk of negatively impacting the community. The CCIF is however able to demonstrate potential social risk areas. If applied to additional coastal carbon offset projects, best practice documents, community engagement and the monitoring and evaluation process of such projects can be improved.

Constraints and opportunities for market-based finance for the restoration and protection of blue carbon ecosystems

Vanderklift MA, Marcos-Martinez R, Butler JRA, Coleman M, Lawrence A, Prislan H, Steven ADL, Thomas S. Constraints and opportunities for market-based finance for the restoration and protection of blue carbon ecosystems. Marine Policy [Internet]. In Press . Available from: https://www.sciencedirect.com/science/article/pii/S0308597X18304846
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $35.95
Type: Journal Article

The restoration and protection of “blue carbon” ecosystems – mangroves, seagrasses, and tidal marshes – has potential to offset greenhouse gas emissions and improve coastal livelihoods. However, realisation of this potential relies on global investment in restoration and protection, which in turn relies on appropriate funding mechanisms that are currently impeded by multiple constraints. Constraints include commercial considerations by private investors (including reliable estimates of financial returns, risk quantification and management, and supply chain impacts), regulatory and legal uncertainty (such as the complexity of property rights in coastal areas, policy coordination across jurisdictions, and stable policy consistent with the duration of blue carbon projects). There are, however, opportunities to improve on current practices, including better stakeholder engagement (including social license to operate, and knowledge transfer to promote best practices), and targeted use of public and philanthropic funding (to subsidise demonstration projects, reduce financial risk through collaterals, and promote low-profit but high co-benefit projects). In this paper, a strategy for the realisation of potential benefits through commercially viable and scientifically robust blue carbon initiatives is presented alongside insights and guidance for the policy, research, civil society, and private sectors to achieve these important long-term outcomes.

Analysis of forty years long changes in coastal land use and land cover of the Yellow Sea: The gains or losses in ecosystem services

Yim J, Kwon B-O, Nam J, Hwang JHwan, Choi K, Khim JSeong. Analysis of forty years long changes in coastal land use and land cover of the Yellow Sea: The gains or losses in ecosystem services. Environmental Pollution [Internet]. 2018 ;241:74 - 84. Available from: https://www.sciencedirect.com/science/article/pii/S0269749118313848
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $35.95
Type: Journal Article

The drastic land cover change and its impacts in the Yellow Sea have long been significant issues in terms of coastal vulnerabilities, but holistic data analysis is limited. The present study first reports 40 years long geographical changes of the Yellow Sea coasts including all three neighboring countries of China, North Korea, and South Korea. We delineated tidal flats by analysis of Landsat series satellite imageries (662 scenes) between 1981 and 2016. A total area of the Yellow Sea tidal flats has been considerably reducing for the past 36 years, from ∼10,500 km2 (1980s) to ∼6700 km2(2010s), say ∼1% annual loss. A majority loss of tidal flats was mainly due to the grand reclamations that conducted in almost entire coast of the Yellow Sea, particularly concentrated in the 1990s-2000s. Coastal reclaimed area during the past four decades reached ∼9700 km2, including ongoing and planned projects, which corresponds to over half the area of precedent natural tidal flats of the Yellow Sea. The potential carbon stocks in the eight representative regions with large scale reclamation indicated significant loss in carbon sink capacity in the South Korea's coast (∼99%), while evidenced a lesser loss from the China's coast (∼31%). It was noteworthy that the progradation of tidal flats after the reclamation in China's coast significantly reduced the loss of carbon sequestration. According to the ecosystem services valuation for the Yellow Sea, a total loss was estimated as ∼8 billion USD yr−1 with relatively high proportional loss (up to 25%) of climate regulating services (viz., carbon sequestration). Overall, huge losses in ecosystem services being provided by the Yellow Sea natural tidal flats need immediate action to prevent or at least alleviate accelerating ecological deteriorations. Finally, future conservative policy direction on coastal wetlands management has been proposed towards enhancement of marine ecosystem services.

Grazers extend blue carbon transfer by slowing sinking speeds of kelp detritus

Wernberg T, Filbee-Dexter K. Grazers extend blue carbon transfer by slowing sinking speeds of kelp detritus. Scientific Reports [Internet]. 2018 ;8(1). Available from: https://www.nature.com/articles/s41598-018-34721-z
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Marine plant communities such as kelp forests produce significant amounts of detritus, most of which is exported to areas where it can constitute an important trophic subsidy or potentially be sequestered in marine sediments. Knowing the vertical transport speed of detrital particles is critical to understanding the potential magnitude and spatial extent of these linkages. We measured sinking speeds for Laminaria hyperborea detritus ranging from whole plants to small fragments and sea urchin faecal pellets, capturing the entire range of particulate organic matter produced by kelp forests. Under typical current conditions, we determined that this organic material can be transported 10 s of m to 10 s of km. We show how the conversion of kelp fragments to sea urchin faeces, one of the most pervasive processes in kelp forests globally, increases the dispersal potential of detritus by 1 to 2 orders of magnitude. Kelp detritus sinking speeds were also faster than equivalent phytoplankton, highlighting its potential for rapid delivery of carbon to deep areas. Our findings support arguments for a significant contribution from kelp forests to subsidizing deep sea communities and the global carbon sink.

Coastal Wetlands: Conservation of Blue Carbon Ecosystems for Climate Change Mitigation and Adaptation

Serrano O, Kelleway JJ, Lovelock C, Lavery PS. Coastal Wetlands: Conservation of Blue Carbon Ecosystems for Climate Change Mitigation and Adaptation. In: Elsevier; 2019. pp. 965 - 996. Available from: https://www.sciencedirect.com/science/article/pii/B9780444638939000289
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $31.50
Type: Book Chapter

Emission of greenhouse gases, including carbon dioxide (CO2), has been the main cause of climate change and global warming since the mid-20th century. Blue carbon (BC) ecosystems, which include tidal marshes, mangroves, and seagrass meadows, play a key role in climate change mitigation and adaptation. Despite occupying only 0.2% of the ocean surface, they contribute 50% of carbon burial in marine sediments, equivalent to the sequestration of 1%–2% of current global CO2 emissions from fossil fuel combustion. Conversely, damage to these ecosystems risks the release of that carbon back to the atmosphere. Conserving and restoring BC ecosystems not only maintains COsequestration capacity but also services essential for climate change adaptation along coasts, including prevention of shoreline erosion. However, BC ecosystems rank among the most threatened ecosystems on earth. Urgent action is needed to prevent further degradation, to avoid additional greenhouse emissions, as well as restoring degraded habitats to recover their climate change mitigation potential.

Coastal morphology explains global blue carbon distributions

Twilley RR, Rovai AS, Riul P. Coastal morphology explains global blue carbon distributions. Frontiers in Ecology and the Environment [Internet]. 2018 . Available from: https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/fee.1937
Freely available?: 
Yes
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $38.00
Type: Journal Article

Because mangroves store greater amounts of carbon (C) per area than any other terrestrial ecosystem, conservation of mangrove forests on a global scale represents a potentially meaningful strategy for mitigating atmospheric greenhouse‐gas (GHG) emissions. However, analyses of how coastal ecosystems influence the global C cycle also require the mapping of ecosystem area across the Earth's surface to estimate C storage and flux (movement) in order to compare how different ecosystem types may mitigate GHG enrichment in the atmosphere. In this paper, we propose a new framework based on diverse coastal morphology (that is, different coastal environmental settings resulting from how rivers, tides, waves, and climate have shaped coastal landforms) to explain global variations in mangrove C storage, using soil organic carbon (SOC) as a model to more accurately determine mangrove contributions to global C dynamics. We present, to the best of our knowledge, the first global mangrove area estimate occupying distinct coastal environmental settings, comparing the role of terrigenous and carbonate settings as global “blue carbon” hotspots. C storage in deltaic settings has been overestimated, while SOC stocks in carbonate settings have been underestimated by up to 50%. We encourage the scientific community, which has largely focused on blue carbon estimates, to incorporate coastal environmental settings into their evaluations of C stocks, to obtain more robust estimates of global C stocks.

Seagrasses of Australia - Estimating Seagrass Blue Carbon and Policy Implications: The Australian Perspective

Ralph PJ, Crosswell JR, Cannard T, Steven ADL. Seagrasses of Australia - Estimating Seagrass Blue Carbon and Policy Implications: The Australian Perspective. In: Larkum AWD, Kendrick GA, Ralph PJ Cham: Springer International Publishing; 2018. pp. 743 - 758. Available from: https://link.springer.com/chapter/10.1007/978-3-319-71354-0_22
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $29.95
Type: Book Chapter

Blue carbon policy supports carbon sequestration whilst also conserving our remaining seagrass meadows. The complex biogeochemical processes within the sediment of seagrass meadows are responsible for the longevity of the stored carbon. Carbon stock and accumulation rates are controlled by the interaction of hydrodynamic, geochemical and biotic processes unique to each meadow. Carbon content (stock and flux) of a meadow must be quantified for inclusion in carbon accounting, whether for market trading or national greenhouse gas accounting. Management of seagrass blue carbon also requires estimates of additionality, leakage, permanence, conversion and emission factors.

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