Search

Blue carbon, a concept that emerged in the last decade, has received increasing attention in recent years. The development of blue carbon as a nature-based solution is crucial to global climate governance, biodiversity conservation, and restoration of fishery resources. This study utilized CiteSpace visualization software to conduct bibliometric and systematic analyses of 3474 papers retrieved from the Web of Science Core Collection in 2003–2022, depicting a comprehensive framework of international research on blue carbon, exploring hotspots and trends, and proposing future directions and implications for ocean and coastal management. Overall, blue carbon research has experienced the early exploration period (2003–2007) based on scientific concepts, the development period (2008–2015) of research on carbon sequestration mechanisms and functions of different organisms and ecosystems, and the outbreak period (2016–2022) of carbon sink system quantification and management based on model prediction. Co-authorship analysis indicated that blue carbon research collaborates well across intuitions and countries, while collaboration among authors needs to be strengthened. Thematic evolution and hotspot analysis based on cited references and keywords revealed that coastal wetlands, especially mangroves, are a popular research theme, and the functional protection and development of management strategies for coastal ecosystems are major current research hotspots. In addition, it emphasized the need to focus on the protection, restoration and creation of blue carbon ecosystems (BCEs), develop sustainable marine ranching to promote blue carbon trading, explore more potential emerging blue carbon, and strengthen the management of blue carbon from the social level in the future. This paper combines traditional bibliometric review with modern visual analysis software to carry out network metrics, clustering and visualization of the blue carbon thematic literature from multiple perspectives, which reflects its novelty. It provides the latest, in-depth and comprehensive insights into blue carbon research that will serve as valuable reference for relevant scholars, managers and governments. [Display omitted] • Blue carbon field has experienced exploration, development and outbreak periods. • Blue carbon research is well-collaborated across institutions and countries. • Coastal wetlands, especially mangroves, have been a popular central research area. • Protection and management of coastal ecosystems are new hotspots in research. • Propose ocean and coastal management implications for realizing the potential of blue carbon. [ABSTRACT FROM AUTHOR]

The saltmarsh carbon storage potential is a key topic in blue carbon research and climate policy. Ecosystem service valuations provide valuable information to policymakers for habitat management and climate change mitigation policies. Yet, only few saltmarsh valuation studies have included the carbon storage service in the UK context. This paper investigates how the public values saltmarsh ecosystem services, focussing on the carbon storage service. We used a choice experiment to elicit the willingness to pay (WTP) of a representative sample of the Scottish public to support interventions that would maintain or improve the provision of these services. Furthermore, we tested the effect of information on individuals' preferences and WTP with a split sample approach where one group received a treatment in the form of additional information. We found that (i) all attributes had a significant influence on individuals' choices; (ii) both groups had, on average, a positive marginal WTP for all presented ecosystem services; (iii) the treated sample had, on average, no significantly different marginal WTP for carbon storage than the control group. This paper adds to the limited literature on the saltmarsh carbon storage ecosystem service and demonstrates a developed nation's public's openness to nature-based climate change mitigation solutions. [Display omitted] • The Scottish public on average prefers saltmarsh management over the status quo. • Providing additional information reduced heterogeneity in WTP for carbon storage. • Most respondents preferred an improvement of all saltmarsh ecosystem services. • Therefore management should focus on both climate change mitigation and adaptation. [ABSTRACT FROM AUTHOR]

Mangroves, tidal marshes, and seagrasses have been recognized as blue carbon coastal ecosystems as they accommodate large carbon stocks, enable long-term carbon storage, have the capacity to control greenhouse gas emissions and possess the potential to reduce the rise in atmospheric CO 2 levels. In the tropical and subtropical intertidal zones, mangroves show significant productivity and rapid deposition rates. Mangroves play an important role in capturing, transforming, and storing CO 2 in the atmosphere into coastal sediments for a long time, displacing organic carbon from the coastal zone to the offshores and the ocean. Mangroves also help in preventing storms, hurricanes, coastal erosion, and tidal waves. Recently, mangroves have been threatened by natural and anthropogenic activities such as urbanization, pollution, aquaculture and tourism. They are expected to hamper their essential services, such as coastal defense, breeding grounds for aquatic organisms' seafood supply, etc. Despite the importance of mangrove forests in carbon sequestration and the numerous goods and services they offer humans, wood and non-wood forest products, food, fisheries, medicines, eco-tourism, and recreation. These mangrove ecosystems are deteriorating at alarming rates, necessitating immediate intervention. Thus, the protection, restoration and conservation of this ecosystem are gaining considerable attention from researchers across the globe. This paper provides information on different mangrove adaptations, their mechanisms, roles in the ecosystem, carbon estimation, influencing factors, threats, and conservation strategies for carbon sequestration in this invaluable coastal habitat. • Carbon sequestration is the most crucial ecosystem function among the ecosystem services offered by coastal ecosystems. • Mangroves play an important role in capturing, transforming, and storing carbon. • Blue carbon ecosystems play a critical role in regulating our climate. • Various factors that impact carbon sequestration and conservation strategies were discussed. • Economic incentives via ecotourism in mangrove ecosystems were discussed. [ABSTRACT FROM AUTHOR]

Blue carbon (BC) research has progressed over the years and is continuously evolving. Several existing review papers are available and scrutinized BC research, yet, knowledge gaps and overlaps in science and practice remain a challenge. Thus, we conducted a literature review on 1179 BC-related documents including peer-reviewed articles, technical reports/policy briefs, books/book chapters, conference presentation abstracts, dissertations/theses, and news articles. The work undertaken was guided by three research objectives – (1) to identify the knowledge gaps, trends, and updates in BC literature, (2) to determine the geographic distribution of BC research, and (3) to review the timeline of BC research and elucidate critical issues that potentially drag BC advancement. Key results showed, that, firstly, BC literature favors academic research papers over gray literature (e.g., guidelines, policy briefs). This is critical since research papers are hard to access and process by non-technical persons and practitioners worldwide, thus, promoting gray publications particularly those dedicated to policymakers and coastal managers such as policy briefs and technical manuals are highly encouraged. Secondly, there is an uneven geographic distribution of BC documents, roughly reflecting weak international collaborations among scholars from developing and developed countries. Additionally, this can be attributed to scholar's limited capabilities and international networks. Lastly, BC research remained in favor of natural/physical/applied sciences in comparison to social and policy-oriented papers. Despite this, we noted that the number of social-driven publications in the last two years is increasing, which can change trends in the future. The findings of this review, covering the last 12 years of BC research, can be instrumental to coastal managers and/or practitioners in terms of developing state of the art BC management strategies that are science-based. Moreover, the results can support scholars by complementing their future research agendas to avoid unnecessary overlaps and/or redundancies that can potentially drag the advancement of BC science. [ABSTRACT FROM AUTHOR]

Mangrove wetlands are important sites of carbon burial amounting to 15% of the global total for coastal environments even though they comprise only 0.5% of the coastal area. Carbon fixation and burial in mangrove wetlands are sensitive to environmental changes but difficult to quantify. In this paper, records of mangrove-derived organic carbon (OC) burial were analyzed for two mangrove wetlands, Bamen Bay estuary (BMB) and Danzhou Bay estuary (DZB), in Hainan Province, China, over timescales of the last few decades. The mangrove-specific biomarker taraxerol and the more established proxies of C/N ratio and δ13C of bulk OC were used to investigate OC sources and burial history. A mixing model based on C/N ratios, bulk OC δ13C values and taraxerol concentrations indicates that mangrove-derived OC accounts for 25 ± 14% (mean ± SD) of sedimentary OC burial in (BMB and 16 ± 7% in DZB since 1960 CE. The estimated top 100 cm organic carbon storage was 242 Mg/ha in BMB and 89 Mg/ha in DZB. The carbon sequestration rate in BMB increased from 0.29 Mg/ha/yr to 6.54 Mg/ha/yr after 2012 CE, likely as a response to local mangrove protection since 1981 CE. Compared to the less-protected DZB, mangroves in BMB contributed 31% more to the sedimentary OC pool after mangrove protection, suggesting that mangrove protection has the potential to increase ecosystem health and to increase carbon burial in coastal wetlands. • Taraxerol was used to quantify mangrove OC contribution in sediments. • Mangrove OC contribution increased by 31% due to local protection. • Mangrove OC accounted for up to 25% of sedimentary OC burial. [ABSTRACT FROM AUTHOR]

The development of marine carbon sink fisheries is both an important support to achieve the goal of net zero emissions as well as a hot topic concerning the livelihood of fishermen. Although it has been shown that there is great potential for carbon sinks in terms of environmental benefits, the lack of economic benefits in the short term is a hindrance that prevents marine carbon sink fisheries from being accepted by practitioners, especially fishermen groups. There is need to stimulate fishermen's enthusiasm for cooperative development of marine carbon sink fisheries and to promote marine carbon sink fisheries in order to achieve high efficiency and effectiveness. This paper adopts a complex network evolutionary game, based on the assumptions of WS small-world model on social network relationships, focuses on fishermen groups, and explores the dynamic evolutionary law of cooperative behavior diffusion in development of marine carbon sink fisheries. The results of the study show that (1) the government can accelerate the diffusion of cooperative behavior in the pre-development stage of marine carbon sink fisheries through subsidies, supplemented by certain punishments to curb the betrayal behavior, with the strength of the rewards and punishments dynamically adjusted according to the changes in the risks of implementation of marine carbon sink fisheries. (2) In the long term, higher value of marine carbon sink fisheries and their derived products is the essential demand of fishermen, which can effectively improve the depth of diffusion of fishermen's cooperation in developing marine carbon sink fisheries. (3) To avoid the spread of betrayal in the later stages of marine carbon sink fisheries development, the government can gradually reduce production subsidies and convert them into environmental subsidies in the sale process. • Directly measuring the amount of fishery resources is difficult, which makes fishermen's betrayal more likely to occur. • In the later stage, the spread of betrayal can be curbed by increasing subsidies for carbon sink fishery sales. • It is necessary to grasp the combination of policies in a timely manner under dynamic risks. [ABSTRACT FROM AUTHOR]

The European Marine Board recently published a position paper on linking oceans and human health as a strategic research priority for Europe. With this position paper as a reference, the March 2014 Cornwall Oceans and Human Health Workshop brought together key scientists, policy makers, funders, business, and non governmental organisations from Europe and the US to review the recent interdisciplinary and cutting edge research in oceans and human health specifically the growing evidence of the impacts of oceans and seas on human health and wellbeing (and the effects of humans on the oceans). These impacts are a complex mixture of negative influences (e.g. from climate change and extreme weather to harmful algal blooms and chemical pollution) and beneficial factors (e.g. from natural products including seafood to marine renewable energy and wellbeing from interactions with coastal environments). Integrated approaches across disciplines, institutions, and nations in science and policy are needed to protect both the oceans and human health and wellbeing now and in the future. [ABSTRACT FROM AUTHOR]

Abstract This paper presents the first aquatic CO 2 and CH 4 flux estimates from a macro-tidal mangrove creek located in the 0–5° latitude band, where ∼30% of the world's mangroves occur. High resolution dissolved CO 2 , CH 4 and 222Rn (a natural pore-water tracer) concentrations were measured over a spring-neap tidal cycle from a mangrove tidal creek located in North Brazil (∼0.8°S). Surface water p CO 2 , CH 4 and 222Rn ranged from 592 to 15,361 μatm, 58 to 1469 nM, and 585 to 16,583 dpm m−3 with considerable temporal variability observed semi diurnally (i.e. hourly) and over the spring-neap cycle (i.e. weekly). Tidally-driven pore-water exchange (tidal pumping) drove surface water p CO 2 and CH 4 , leading to high concentrations at low-tide (semi-diurnal variability). Higher p CO 2 and CH 4 were also observed after the inundation of the upper inter-tidal flat, with peak values coinciding with the "first flush" of aged pore-waters. We hypothesise that additional pore-water exchanges occur during forest inundation in macro-tidal mangrove systems, controlling mangrove creek water p CO 2 and CH 4 over spring-neap cycles. Estimated CO 2 and CH 4 water-atmosphere fluxes were 174 ± 129 mmol m−2 d−1 and 855 ± 406 μmol m−2 d−1, respectively. These emissions are amongst the highest reported for mangrove systems worldwide and suggests that the most recent global estimates based mostly on data from higher latitudes may have underestimated the role of mangroves in greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

Abstract Carbon capturing coastal and marine habitats around the world are decreasing in extent every year, habitats found in abundance in Small Island Developing States' territories. However, these habitats are under threat by increased levels of economic activities and extreme weather events. Consequently, as those ecosystems become scarce their value is expected to increase. In this paper the "value of information", the increase in knowledge that renders a system or a function more valuable, from marine habitat mapping is presented through the (monetary) valuation of one regulating service provided by the newly mapped habitats. Mapping a section of a channel with a multibeam echosounder revealed more seagrass resources than in previous studies. Using values for both the Social Cost of Carbon and Abatement Cost methods, from the literature we estimate the value of the carbon sequestration and storage service these seagrass meadows provide. The impacts of hurricanes in the newly mapped seagrasses were also investigated. Despite the costs of mapping, monitoring and of projected losses of ecosystem services provision due to hurricanes, net benefits over a time period of 50 years were considerably larger. The new information provided highlights carbon capturing habitats as more important, enabling the "value of information" to inform policymaking. Graphical abstract Unlabelled Image Highlights • An 800% increase in known seagrass resource was found in a 36 km2 area. • Newly mapped seagrasses appear to be resilient in the event of hurricanes occurring. • Carbon sequestration benefits are valued through avoided cost methods Net Present Values for the 50-year period are 3% of the country' GDP. • Net Present Values for the 50-year period are 3% of the country' GDP. • Costs of mapping and monitoring of seagrasses decrease NPVs only marginally. [ABSTRACT FROM AUTHOR]

Highlights • A model of mangrove restoration through local community engagement. • Incorporates risk of future loss to mangroves from cyclones in the Sundarbans. • Local communities may over-invest in mangrove restoration in presence of risks. • Socially optimal level of mangrove restoration in hazardous regions is lower. • Due to stability of the stored carbon, high restoration becomes desirable at low risks. Abstract Restoration of mangrove forests through community involvement offers the promise of reaping multiple environmental dividends while simultaneously helping local communities augment their livelihoods through generating payments from ecosystem services. However, there exist several challenges to the success of such restoration projects. In this paper, one such key challenge, that of the risk of extreme climatic events, is considered. Optimal rate of mangrove restoration on public coastal lands is derived in the presence of a future risk of extreme cyclones decimating the mangrove forests. Using the context of the Sundarbans region of India, which has the largest mangrove forests on the planet, we develop a model of community led restoration efforts where local inhabitants receive credit for carbon sequestered in the process. Results indicate that when communities do not receive outside support through wages or reimbursement of plantation costs, restoration efforts get spread over a longer time horizon. Presence of a risk of future cyclone events that could destroy the restored forests prompts speedier restoration, which may not be an optimal outcome from the perspective of global carbon mitigation efforts. An optimal plan that is primarily concerned with deriving sequestration benefits from newly restored mangroves leads to lower restoration levels in the presence of higher cyclone risks. However, irrespective of the institutional setting under which restoration is incentivized, given the relatively stable nature of underground carbon stored in mangroves, it is optimal to undertake higher restoration efforts when climatic risks are low. [ABSTRACT FROM AUTHOR]

Blue carbon trading provides not only an extra impetus to the diversification of the carbon trading system, but also substantial support for achieving the net-zero greenhouse gas emission target. Being aware of its importance, this study strives to lay a theoretical foundation for it and help blue carbon fully realize its value. While staying realistic and considering the complex relationship among the relevant participants in blue carbon trading, as well as their objective needs, this paper develops an evolutionary game model consisting of a demander, a supplier, the government, and a third-party institution to make a simulation analysis based on certain key parameters in order to determine how to maximize efficiency of blue carbon trading. The results show: (1) an extraordinarily high or low price will simply benefit one party to a transaction, but at considerable cost to the interests of the other party, which hence is unfavorable to blue carbon trading in the long run; (2) the government may increase, directly or indirectly, the willingness of the other three parties to participate in the trading through appropriate regulations, especially through adjustments to the emission quotas, which has the most significant impacts on overall blue carbon trading; (3) although the final choices of the demander, supplier, and third-party institution on whether to participate in a transaction are generally consistent, nonetheless, high derivative values of blue carbon products may drive the supplier to continue to engage in the related industry even when the demander has no purchase intent. In this case, the supplier does objectively provide a continuous supply of blue carbon, though it does not subjectively intend to do so. • Generally, the willingness of some participants is consistent. • Quota adjustments and price changes have notable impacts on participants. • Higher derivative value enables the supply of blue carbon to be maintained. • Government can set higher offset limits for blue carbon based on its nature. [ABSTRACT FROM AUTHOR]

Anthropogenic CO 2 emissions are one of the principal driving forces of climate change. Climate change leads to systematic changes of ecosystems that cause significant impacts on species interactions, ecosystem processes, and result in profound socio-economic consequences. While carbon offsetting of terrestrial forests and their monetary value are well accepted, the carbon offsetting potential and value of coastal and marine ecosystems (Blue Carbon, BC) remains excluded from the international carbon accounting framework. In this study, we estimated the carbon offsetting value of kelp forests (Ecklonia radiata) against urchin barrens (dominated by crustose coralline algae) using the standing stock biomass as a metric. We propose that standing stock biomass is a crucial next step in introducing BC to the general carbon offsetting framework. Our approach is informed by long-term ecological research conducted in a marine reserve, which highlights the potential of utilizing trophic cascades to limit the dominance of urchin barrens in shallow coastal habitats. We found that the value of carbon standing stock in current kelp forests with reforestation in the Hauraki Gulf Marine Park (HGMP) is worth up to $NZ 7.9 million, based on 2021 carbon market pricing in New Zealand. This simple step towards realizing the value of marine conservation and its multiple benefits to society highlights the missed opportunities when policy and plans do not align with ecology and economics. Including the ocean's contributions to carbon storage is a critical step in using monetization techniques to overcome climate change challenges. Monetizing the carbon offsetting value of kelp forests contributes to establishing funding mechanisms to attract diverse investments in marine ecosystem restoration while providing ecological benefits in ocean governance. • This paper draws attention to the missed opportunity of including kelp forest in the current carbon offsetting framework. • The CO 2 stored in kelp standing stock biomass could be worth up to NZD 7.9 million (2021, with reforestration) in the Hauraki Gulf Marine Park. • Monetizing the carbon storage value of kelp contributes to the establishment of funding mechanisms to attract investments as a nature-based solution to climate change. [ABSTRACT FROM AUTHOR]

[Display omitted] • Landscape of blue carbon research from the perspective of bibliometrics. • Blue carbon ecosystem was the main research area, but macroalgae deserve attention. • Artificial intervention and methods are potential hotspots in the future research. • Statistics, co-occurrence analysis and thematic evolution are main used methods. Blue carbon sequestration is a nature-based solution to environmental problems caused by climate change and has a significant positive impact on the planet and human well-being. This paper bibliometrically and systematically analyzed 2,613 studies found in the Web of Science Core Collection (WoSCC) from 2003 to 2021 to explore the hotspots and trends of blue carbon research using the Bibliometrix package in R studio and VOSviewer software. The results based on network co-occurrence analysis indicated that mangroves, seagrasses, and salt marshes were the major blue carbon ecosystems (BCEs), and mangrove carbon sinks were the most popular central research area. Furthermore, phytoplankton and microalgae have essential roles in the marine carbon cycle and bioenergy utilization, as revealed by the high proportion of published literature, while the carbon transport mechanisms of seagrass and macroalgae was understudied. Thematic evolution analysis revealed that remote sensing was the most commonly used technology as an emerging research field for ecological monitoring and ecological investigation in blue carbon research in recent years. In addition, increasing carbon sinks by artificial approaches, fishery carbon sinks, and carbon sequestration by macroalgae have been potential hotspots for blue carbon research development. The findings from this study shed light on the trends of blue carbon in the past eighteen years, current research points in the field, and areas that need more research investment going forward. [ABSTRACT FROM AUTHOR]

Payments for carbon services (C-PFES) is a mechanism used to meet national emission reduction targets via either forest protection or reforestation. However, while carbon is a unique environmental service traded in national and international markets, there are challenges in implementing C-PFES schemes at the local level. Simply put, the views of local participants who will undertake the abatement activities have not been considered. By analysing at the local level the views of potential sellers, potential buyers and intermediaries, this paper investigated the feasibility of applying C-PFES for mangroves in Ca Mau province, Vietnam. While local stakeholders had a strong understanding of the likely impacts of climate change on their production and were aware of the environmental roles of mangroves, the carbon sequestration capacity of mangroves was rarely mentioned, and this will be a challenge in implementing a C-PFES scheme. While potential sellers and intermediaries showed strong support for C-PFES, potential buyers were less likely to join the scheme. As the carbon sequestration capacity of mangroves can also be purchased by international entities, it is recommended that the scope of the current Vietnamese C-PFES scheme be broadened to allow participation of entities from outside Ca Mau province, including private companies, government agencies and international investors. We also identified the need for education training programs to enhance stakeholders' perspectives prior to the implementation of C-PFES at the local level. This study provides insights for countries with mangrove ecosystems seeking to implement a C-PFES. [ABSTRACT FROM AUTHOR]

Carbon sequestration of blue carbon ecosystems worldwide is as high as 237.6 Tg C/a. China is one of the countries with the most resources of blue carbon, with carbon sequestration of 0.835 Tg C/a. To develop blue economy and facilitate the fulfillment of carbon neutrality, it is of great significance for China to build the blue carbon trading market (BCTM). This paper aimed to improve the participation probability of stakeholders to construct an effective BCTM through evolutionary game theory. First, we constructed a tripartite evolutionary game model including the governments, the suppliers of blue carbon (SBC) and the demanders of blue carbon (DBC), based on the corresponding cost and benefit in BCTM. To further reveal the factors affecting the cooperation of above parties, we analyzed the sensitivity of the stakeholders through five parameters, i.e., proportion of subsidies, unit carbon tax, blue carbon credits, unit price of blue carbon credits, and the cost of carbon emission reduction unit. To verify the game model, a case study of blue carbon credits of mangrove trading was performed. The main conclusions are as follows. In the initial stage of BCTM, the governments need to play a leading role in regulating and incentivizing motivation of the SBC and DBC. Subsidies and carbon taxes are conducive to promoting BCTM to develop into the middle stage. In the middle stage, price and quota of BC credits are two primary parameters to affect the evolutionary results of above three groups. Thus, it's necessary for the governments to adjust these parameters in time. When the trading scale and operation mode of BCTM approaching stable, the market will enter into the mature stage. Then, the governments can reduce subsidies to save fiscal expenditure and lessen the intervention, so as to gradually withdraw from the market. The above conclusions can provide a theoretical basis and reference for the construction of efficient BCTM and promote the integration of blue carbon into the carbon market in China. [Display omitted] [ABSTRACT FROM AUTHOR]

Ocean and marine ecosystems provide a range of valuable services to humans, including benefits such as carbon sequestration, whose economic value are as yet poorly understood. This paper presents a novel contribution to the valuation of carbon sequestration services in marine ecosystems with an application to the Mediterranean Sea. We combine a state-of-the-art biogeochemical model with various estimates of the social cost of carbon emissions to provide a spatially explicit characterization of the current flow of values that are attributable to the various sequestration processes, including the biological component. Using conservative estimates of the social cost of carbon, we evaluate the carbon sequestration value flows over the entire basin to range between 127 and 1722 million €/year. Values per unit area range from −135 to 1000 €/km 2 year, with the exclusive economic zone of some countries acting as net carbon sources. Whereas the contribution of physical processes can be either positive or negative, also depending on the properties of incoming Atlantic water, the contribution of biological processes to the marine “blue carbon” sequestration is always positive, and found to range between 100 to 1500 million €/year for the whole basin. [ABSTRACT FROM AUTHOR]

Plastic bags are among the most discarded waste items as they are generally only used once and are often improperly eliminated and transported by rivers and estuaries to the ocean. We developed an experimental design to mimic the effect of plastic bag deposition in a tropical estuary and investigated its short-term impact on benthic community structure. We observed a significant influence of the presence of plastic bags on the abundance, richness and diversity of benthic fauna after an eight-week exposure period. Plastic bags acted as a barrier and interfered in processes that occur at the water-sediment interface, such as organic matter and silt-clay deposition. Our results indicate that plastic bags, in addition to directly affecting benthic fauna, may alter processes such as carbon burying, known as "blue carbon", thus making its storage in the sediment more difficult. [Display omitted] • This study experimentally investigated the effects of plastic bag deposition on the benthic fauna of an estuarine ecosystem • After an eight-week exposure period, the structure of benthic communities under plastic bags was significantly altered • Plastic exposure affected both macrofaunal diversity and density, as well as organic matter deposition and silt-clay contents • Our results suggest that plastic bag cover interferes with "blue carbon" storage in estuarine environments [ABSTRACT FROM AUTHOR]

Seagrasses are distributed all along the coast of the Mediterranean Sea being Posidonia oceanica and Cymodocea nodosa the most common species. They promote sedimentation, leading to the formation of well-structured soils. Over the last decade, a growing attention has been paid to their role as CO 2 sinks in the form of organic carbon (C org) and to their use as environmental archives. However, most of the knowledge about pedogenetic processes in these soils refer to the rhizosphere. This study aims to understand seagrass soils biogeochemistry in the rhizosphere and below, which in turn can help to understand their long term formation processes. Fifteen cores were strategically sampled along a 350 km stretch of the Southeast Iberian coast, and analyzed for elemental composition (XRF core-scanning), magnetic susceptibility, C org content and gran size distribution. The cores were dated by 210Pb and 14C-AMS techniques to estimate soil accretion. Principal component analysis was used to explore the main geochemical processes linked to soil formation. The results showed that terrestrial runoff plays a key role in meadow soil composition. Furthermore, C org accumulation did not follow any general depth trend in our soil records, suggesting that temporal variation in C org inputs is an important factor in determining carbon depth distribution within the soil. We obtained evidence that the establishment of well-developed, stable C. nodosa meadows in the Mediterranean Sea may be promoted by adverse environmental conditions to P. oceanica settlement. Metal's behavior within the meadow deposit and their interaction with organic matter and carbonates is unclear. The results presented in this paper highlight the importance of the influence of land-based inputs in the characteristics of seagrass meadow deposits, highly determining their C org content, as well as the need for further studies on metal behavior, to understand their full potential as environmental records. Unlabelled Image • There is a growing interest in seagrass soil formation processes. • Fifteen cores of the two main Mediterranean seagrass species were sampled. • Principal component analysis was used to summarize diverse geochemical proxies. • Terrestrial influence explained 55% of the variance in soil texture and composition. • The temporal variability in organic matter inputs affected C org accumulation. [ABSTRACT FROM AUTHOR]

Blue Carbon (BC) strategy refers to the approaches that mitigate and adapt to climate change through the conservation and restoration of seagrass, saltmarsh and mangrove ecosystems and, in some BC programs, also through the expansion of seaweed aquaculture. The major losses of coastal habitats in combination with the commitments of China under the Paris Agreement provide unique opportunity and necessity to develop a strong Chinese BC program. Here, we (1) characterize China's BC habitats, examine their changes since 1950 along with the drivers of changes; (2) consider the expansion of seaweed aquaculture and how this may be managed to become an emerging BC resource in China, along with the engineering solutions required to enhance its potential; and (3) provide the rationale and elements for BC program in China. We find China currently has 1326–2149 km2 wild and 2–15 km2 created mangrove, saltmarsh and seagrass habitats, while 9236–10059 km2 (77–87%) has been lost since 1950, mainly due to land reclamation. The current area of farmed seaweed habitat is 1252–1265 km2, which is close to the area of wild mangrove, saltmarsh and seagrass habitats. We conclude that BC strategies have potentials yet to be fully developed in China, particularly through climate change adaptation benefits such as coastal protection and eco-environmental co-benefits of seaweed farming such as habitat creation for fish and other biota, alleviation of eutrophication, hypoxia and acidification, and the generation of direct and value added products with lower environmental impact relative to land-based production. On this basis, we provide a roadmap for BC strategies adjusted to the unique characteristics and capacities of China. Blue Carbon (BC) plays important roles in climate change mitigation/adaptation. In this paper, we 1) characterize China's BC habitats and examine their changes since 1950 along with the drivers of changes; 2) consider the expansion of seaweed aquaculture and how this may be managed to become an emerging BC resource in China, along with the engineering solutions required to enhance its potential; 3) provide the rationale and elements for BC program in China; and 4) draw a roadmap for BC strategies adjusted to the unique characteristics and capacities of China.Porphyra farm in Dongtou, Wenzhou city, Zhejiang province, China. Image 1 • China's Blue Carbon (BC) habitats, changes and the drivers of changes since 1950. • Potential BC resources, seaweed aquaculture expansion with engineering solutions. • BC Benefits for climate adaptation and co-benefits for environment and economy. • Great potential of China's BC strategies through climate change adaptation benefits. • A roadmap for BC strategies adjusted to the China's characteristics and capacities. [ABSTRACT FROM AUTHOR]

Coastal Blue Carbon is the carbon stored in mangroves, tidal marshes and seagrass meadows. There is an urgent need to protect the coastal ecosystem by developing Blue Carbon economy. In this paper, we investigate the feasibility and mechanism of the Blue Carbon cooperation in the South China Sea Region (SCSR) from an economic angle. We utilize the paradigm of Cobb-Douglas production to stimulate Blue Carbon development and mathematically prove the feasibility of such a cooperation strategy. The Shapley value in game theory is further applied, which not only confirms the reality of this cooperation but also provides an allocation mechanism of the cooperation benefits. The results suggest that there exists a profitable opportunity for the Blue Carbon cooperation in the SCSR. Further discussion and suggestions are provided in promotion of research focus on the Blue Carbon cooperation. [ABSTRACT FROM AUTHOR]

• The carbon market is growing. • Four carbon offset methodologies have been approved for wetland restoration. • Very few wetland restoration carbon offsets transected to date. • Simplification of existing methodologies may facilitate adoption of blue C offsets. Coastal wetlands have been valued for a variety of ecosystem services including carbon sequestration and long term storage. The carbon sequestered and stored in coastal habitat including mangroves, salt marshes, and seagrass beds is termed as blue carbon. However, these systems are threatened mainly due to sea level rise, limited sediment supply, edge erosion, and anthropogenic influences. These habitats require restoration and conservation to continue providing ecosystem services. The incentive for emission reductions, referred to as carbon offsets, is well established for other ecosystems like forestry and agriculture. Some blue carbon offset methodologies or protocols have been certified by various voluntary carbon markets; however to date, a few wetland restoration carbon offset in the US has been transacted. Thus, the goal of this paper is to discuss the existing carbon market and carbon market methodologies applicable to coastal wetland restoration and conservation in the US. Currently, four wetland carbon offset methodologies have been approved in the carbon market. These methodologies are site and/or project-specific depending on the type of the wetlands, vulnerability to loss, and restoration need. The appropriate carbon stock and Green House Gas (GHG) emission assessment is the basis of determining carbon offsets. Simplification of the existing methodologies and development of new site and project-specific methodologies could potentially help to realize blue carbon offsets in practice. The slowly growing demand for carbon offsets in the carbon market could potentially be fulfilled from the blue carbon pool. While this carbon offset is in the early stages, this review may help the inclusion of carbon offset component in the coastal restoration and conservation projects in United States and potentially across the globe. [ABSTRACT FROM AUTHOR]