Coastal sediments are hotspots of biogeochemical processes that are impacting subsurface and overlying water conditions. Fluid composition in sediments is altered through the mineralization of organic matter which, under oxic conditions, further lowers both pH and the carbonate saturation state. As a potential mitigation strategy for this sediment acidification, we explored the effects of mineral additions to coastal sediments. We experimentally quantified carbonate mineral dissolution kinetics of carbonate shells suitable for field application and then integrated these data into a reactive transport model that represents early diagenetic cycling of C, O, N, S, and Fe and traces total alkalinity, pH, and saturation state of CaCO3. Model simulations were carried out to delineate the impact of mineral type and amount added, porewater mixing, and organic matter mineralization rates on sediment alkalinity and its flux to the overlying water. Model results showed that the added minerals undergo initial rapid dissolution and generate saturated conditions demonstrating the potential of alkalinity enhancement in mitigating surface sediment acidification. Aragonite dissolution led to higher total alkalinity concentrations than calcite. Simulations of carbonate mineral additions to sediment environments with low rates of organic matter mineralization exhibited a substantial increase in mineral saturation state compared to sediments with high CO2 production rates, highlighting the environment-specific extent of the effect of mineral addition. Our work indicates that carbonate additions have the potential to effectively buffer surficial sediments over multiple years, yielding biogeochemical conditions that counteract the detrimental effect of low-pH sediment conditions on larval recruitment and potentially increase benthic alkalinity fluxes to support marine carbon dioxide removal (mCDR) in the overlying water.
Continue reading ‘The effect of carbonate mineral additions on biogeochemical conditions in surface sediments and benthic–pelagic exchange fluxes (update)’Posts Tagged 'mitigation'
The effect of carbonate mineral additions on biogeochemical conditions in surface sediments and benthic–pelagic exchange fluxes (update)
Published 11 February 2025 Science ClosedTags: biogeochemistry, chemistry, dissolution, mitigation, modeling, regionalmodeling, sediment
The combined effects of ocean acidification and hypoxia, part 1
Published 5 February 2025 Presentations , Resources ClosedTags: chemistry, mitigation, multiple factors, oxygen
Dr. Richard Feely (NOAA/PMEL) presents on “The Combined Effects of Ocean Acidification and Hypoxia” (Part 1) with Dr. Nina Bednarsek (Oregon State University) at our December 5th, 2024 Partnerships for Tribal Carbon Solutions workshop: Can Rocks Fix the Climate and Heal the Sea? Richard Feely from NOAA’s Pacific Marine Environmental Laboratory discusses ocean acidification in the Pacific Northwest, one of the most vulnerable regions globally. He explains how rising atmospheric CO₂ leads to ocean acidification through chemical reactions that increase hydrogen ion concentration, lowering pH and reducing carbonate availability, which threatens calcifying marine organisms. He highlights how coastal upwelling and biological respiration amplify acidification, making subsurface waters particularly susceptible. Using models and observational data, he demonstrates that acidification is progressing rapidly, with pH declines exceeding EPA water quality criteria in some areas. He emphasizes that adding ocean alkalinity could counteract these changes, offering a potential strategy to mitigate acidification’s impacts.
Global Ocean Health, 29 January 2025. Video.
The hatcheries that are helping oysters pass the acid test
Published 5 February 2025 Media coverage ClosedTags: biological response, fisheries, mitigation, mollusks
Turning oyster bags at low tide at one of Hog Island Oysters’ sites © Remy Hale
Enjoyed at raw bars across the world with a squeeze of lemon, nearly every farmed oyster starts its journey the same way: in a hatchery.
“When hatcheries make baby oysters they start with the moms and pops and they end up with billions of tiny, microscopic oyster larvae that hang out in suspension for a couple of weeks in the seawater, feeding on phytoplankton,” explains Gary Fleener, a scientist-turned-director at Hog Island Oyster Co. Based in California, Hog Island is one of the largest oyster businesses in the US – operating five restaurants, selling wholesale and shipping its oysters directly to homes across the country via their website.
This method of spawning oysters in tanks that are aerated with a mix of fresh seawater and oxygen is similar across the world and is why farmed oysters have a 71 percent higher survival rate than their wild counterparts: hatcheries work.
But in 2007, west coast hatcheries in the United States were shaken. From Washington State to California, entire generations of larvae were dying. And hatchery technicians couldn’t figure out why it was happening. That year, most west coast oyster farmers were left without any seed for their upcoming season.
Describing it as “series of fairly catastrophic die-offs of larvae,” Fleener says that “the complete die off… was a little bit baffling.” At first, hatcheries thought that it was a bacterial outbreak but it turned out to be a product of increased ocean acidity or declining ocean pH. Upwellings of deep ocean water with a pH of 7.8 were too acidic for the oyster larvae. Surface ocean pH is typically above 8.0. Although it was a small difference in alkalinity, for larvae working to create shells, it was too great.
“It ended up serving as a foreshadowing of… [what] the future might do to the shellfish industry,” says Fleener. “The waters that were upwelling at the time that killed all those larvae are what they model for 50 years down the road.”
“Ocean acidification impacts the ability of organisms like oysters, mussels and clams to build shells,” explains Dr Tessa Hill, author of At Every Depth: Our Growing Knowledge of the Changing Oceans and professor at University of California Davis. Dr Hill studies the increasing threat of ocean acidification to see if eelgrass or seaweed can help mitigate the changes and conducts some of her field work near one of Hog Island‘s oyster farms.
“The changes in ocean chemistry associative with rising human-caused carbon dioxide emissions actually change the building blocks that organisms use to make their shells. We’ve seen evidence of smaller, weaker shells in animals such as oysters and mussels,” she explains.
After the die-off, Hog Island invested in building their own hatchery and created a vertically integrated business, a move that they say has helped them become one of the country’s most successful oyster businesses. By 2012, they had acquired a seawater pumping permit from the California Coastal Commission and now mix their intake ocean water with ash, to make it more alkaline and ensure that the larvae oysters are not damaged by declining ocean pH.
Although hatcheries and farmers figured out a workaround, the event sparked many questions for marine scientists and ocean observers. If farmed larvae were struggling under these new conditions, what did it mean for wild species?
Continue reading ‘The hatcheries that are helping oysters pass the acid test’Seagrass influence on mitigating ocean acidification and warming impacts on tropical calcifying macroalgae
Published 28 January 2025 Science ClosedTags: algae, biological response, BRcommunity, laboratory, mesocosms, mitigation, multiple factors, phanerogams, temperature
Highlights
- OA and warming reduce calcium carbonate for marine calcifiers.
- Seagrass can capture excess carbon, possibly mitigating OA effects.
- 12-week study tested algae with/without seagrass under increasing stress.
- M. rosea was affected by OA and warming; H. opuntia by temperature alone.
- Mesophyllum sp. was resilient, and seagrass did not reduce OA impacts.
- Light, flow, combining OA and warming, likely to impact coralline algae
Abstract
Ocean acidification (OA) and warming pose significant threats to marine ecosystems, particularly by reducing calcium carbonate availability for marine calcifiers. Given that seagrasses can capture and store excess carbon, this study aimed to investigate whether seagrasses can mitigate the impacts of OA and elevated temperatures on three calcifying macroalgae: Mastophora rosea, Halimeda opuntia, and Mesophyllum sp. A 12-week mesocosm experiment was conducted, where the algae were cultured with and without seagrass under gradually increasing stress conditions: ambient conditions, OA alone for four weeks, OA combined with elevated (but non-stressful) temperatures (28°C) for four weeks, and OA plus a stress-inducing temperature (31°C) for two weeks. Results indicated that OA and warming negatively affected M. rosea, while H. opuntia was more strongly impacted by temperature alone. Mesophyllum sp. exhibited resilience to both OA and elevated temperatures. Contrary to expectations, the presence of seagrass did not mitigate the negative effects of OA and warming on these calcifying macroalgae species.
Continue reading ‘Seagrass influence on mitigating ocean acidification and warming impacts on tropical calcifying macroalgae’Chapter 8 – Responding to ocean acidification by strengthening marine ecosystem health and resilience
Published 31 December 2024 Science ClosedTags: mitigation, policy, review
Ocean acidification (OA) is a major challenge for marine environmental governance, and one that has given rise to increasing concern as scientific knowledge of the problem and its impacts continues to grow. This chapter thus explores governance arrangements for strengthening marine ecosystem health and resilience and the extent to which they incorporate responses to OA. There is a complex suite of existing governance arrangements for strengthening marine ecosystem resilience that can be harnessed to help vulnerable aquatic systems as the oceans acidify. However, this chapter also demonstrates that management for OA is, at best, a marginal consideration in existing marine biodiversity conservation regimes, despite the significant threat that OA poses to vulnerable aquatic systems. The chapter therefore highlights a significant potential role for marine ecosystem governance arrangements in promoting meaningful steps towards integrated OA and marine conservation management across multiple governance scales. The chapter briefly summarizes OA science and the socio-ecological impacts of acidification in the oceans, before highlighting the role of strengthening marine ecosystem health and resilience in helping vulnerable aquatic systems cope with OA. The chapter also explores relevant governance arrangements and how they address OA at multilateral, regional and in a limited number of domestic jurisdictions, and underlines key governance opportunities and gaps in existing governance frameworks.
Continue reading ‘Chapter 8 – Responding to ocean acidification by strengthening marine ecosystem health and resilience’Local effects of Sargassum beds on the seawater carbonate system and plankton community
Published 30 December 2024 Science ClosedTags: biological response, BRcommunity, chemistry, crustaceans, field, mitigation, North Pacific, phanerogams, phytoplankton, zooplankton
Highlights
- The ecological effect of the sargassum beds depends on seaweed biomass.
- The biomass of the sargassum beds in Weizhou Island reached its peak in spring.
- Sargassum beds significantly influenced the carbonate system and DOC pool in spring.
- Sargassum beds is more likely to alter phytoplankton communities than zooplankton.
Abstract
Sargassum beds are recognized as important habitats for fostering species diversity and capturing blue carbon, exerting significant influence on seawater chemistry and planktonic communities. However, there is still much to uncover about the interactions between these biogenic habitats and seawater chemistry, as well as their impact on plankton communities in the water column. To address this gap, we conducted a study on the functions of natural Sargassum beds in various seasons around the northern part of Weizhou Island in the South China Sea. Our research involved quantifying carbonate chemistry, carbon stock potential, and seawater plankton communities in two distinct areas: the core area in the interior regions of the seaweed beds and the non-core areas at its periphery or external. Our findings revealed an estimated 3.7 km2 of benthic Sargassum, with an overall biomass of 21.2 Gg km−2, reaching its peak productivity in spring, equivalent to 1.14 Pg C km−2. Notably, during spring, the seaweed beds significantly influenced the exchange of CO2 at the air-sea interface, leading to reduced pCO2 (41 μatm) in the core area compared to the non-core area (p < 0.05), thus enhancing the local carbon sequestration capacity. Additionally, we observed significant regional differences in the concentration of dissolved organic carbon (DOC) only during the spring season, indicating the capacity of Sargassum to alter the DOC pool around its habitat. We anticipate that seaweed deposition will become a more frequent occurrence towards the end of the growth period, with increasing fragments facilitating a transition towards phytoplankton-dominated marine ecosystems. Furthermore, the fixation of extra CO2 by seaweed may lead to a pH increase, providing a refuge for copepods from ocean acidification. In summary, our observations suggest that the Sargassum beds plays a substantial role in nearshore carbon cycling and ecological impact, surpassing previous documentation.
Continue reading ‘Local effects of Sargassum beds on the seawater carbonate system and plankton community’Navigating ocean acidification in shellfish aquaculture: stakeholder perspectives of developing strategies in the U.S. Pacific region
Published 12 December 2024 Science ClosedTags: fisheries, mitigation, North Pacific, socio-economy
The marine shellfish aquaculture industry across the U.S. Pacific region faces escalating ocean acidification and its associated challenges. This study examines industry participant perceptions and experiences regarding ocean acidification, additional threats, and future research needs, finding a notable decrease in perceived concern regarding ocean acidification over the past decade. Through structured interviews, broad industry perspectives are explored regarding current practices and two specific ocean acidification adaptation strategies under development: parental priming and native species portfolio expansion. While parental priming garnered cautious support contingent on scientific validation, perceptions of native species expansion were polarized, driven by skepticism about regulatory barriers, economic viability, and scalability. Enhanced environmental monitoring emerged as the most widely supported adaptation measure, underscoring its importance in addressing multiple stressors in addition to ocean acidification. By considering industry and operation characteristics while examining potential decision-making biases, this study provides unique insights for co-producing relevant adaptation strategies. Additionally, the critical role of collaboration between stakeholders, researchers, and policymakers in fostering resilience is emphasized.
Continue reading ‘Navigating ocean acidification in shellfish aquaculture: stakeholder perspectives of developing strategies in the U.S. Pacific region’Addressing the impact of ocean acidification on coral reefs and marine life: a risk assessment for SDG 14 (life below water)
Published 10 December 2024 Science ClosedTags: biological response, corals, Indian, mitigation, review
One of the main issues emerging from environmental change with significant ramifications for marine life is Ocean acidification. It alludes to the cycle by which the sea turns out to be more acidic because of expansion in the concentration of carbon dioxide in the environment. As carbon dioxide levels ascend in climate a critical part is consumed by the sea which prompts a progression of redox responses that decline the pH of ocean water. This peculiarity has broad ramifications for marine life, especially for coral reefs, which are among the most miscellaneous and monetarily significant biological ecosystems in the world. The purpose of this review is to address and assess the impact of ocean acidification on coral reefs and marine life in order to conserve and sustain marine life below water thus fulfilling Sustainable Development Goal 14 (Life below water).
Continue reading ‘Addressing the impact of ocean acidification on coral reefs and marine life: a risk assessment for SDG 14 (life below water)’Marine water acidification and coral bleaching
Published 10 December 2024 Science ClosedTags: biological response, BRcommunity, corals, mitigation, protists, review
Coral reefs are vital marine ecosystems that harbor a significant proportion of the ocean’s biodiversity. However, these ecosystems are increasingly threatened by anthropogenic activities, particularly the emission of greenhouse gases leading to climate change and ocean acidification. Ocean acidification refers to the reduction in pH of marine waters due to the absorption of CO₂ from the atmosphere, forming carbonic acid (H₂CO₃), which dissociates into bicarbonate (HCO₃−) and hydrogen ions (H+), thus lowering pH. This sequence of reactions leads to an increase in hydrogen ion concentration, causing a decrease in pH. The reduction in carbonate ions (CO₃2−) is particularly detrimental to marine calcifiers, including corals, which rely on carbonate for the formation of their calcium carbonate (CaCO₃) skeletons. Coral reefs are constructed by the deposition of CaCO₃ by coral polyps. Zooxanthellae, symbiotic algae living within coral tissues, provide essential nutrients through photosynthesis, facilitating calcification. Acidification disrupts this symbiotic relationship by impairing photosynthetic efficiency and reducing the availability of carbonate ions necessary for skeletal growth. As ocean acidification progresses, the concentration of carbonate ions diminishes, making it energetically more challenging for corals to secrete their skeletons, thereby slowing growth rates and compromising structural integrity. Coral bleaching occurs when corals, under stress, expel their zooxanthellae, leading to a loss of pigmentation and a decline in energy reserves. Stressors include elevated sea temperatures, pollution, and acidification. The loss of zooxanthellae not only deprives corals of their primary food source but also disrupts calcification processes. Thermal stress is a predominant factor in coral bleaching. Elevated sea temperatures can destabilize the photosynthetic machinery of zooxanthellae, producing reactive oxygen species (ROS) that damage both the algae and coral tissues. Prolonged exposure to high temperatures exacerbates acidification effects, intensifying bleaching events. The decline in coral health due to bleaching and acidification has profound ecological impacts, including the loss of habitat for numerous marine species, reduced biodiversity, and compromised fisheries. Socioeconomically, coral reef degradation affects tourism, coastal protection, and the livelihoods of communities dependent on reef resources. Reduction of CO₂ emissions through global policy agreements and renewable energy adoption. Local conservation efforts, such as marine protected areas (MPAs) have the potentials to enhance reef resilience. Conservation efforts may be complemented by research into coral species and strains with higher tolerance to acidification and thermal stress, potentially involving selective breeding and genetic modification. Marine water acidification and coral bleaching are intricately linked phenomena driven by anthropogenic climate change. The decline of coral reefs signals a broader environmental crisis that necessitates urgent scientific, policy, and community responses to mitigate adverse effects and foster adaptive resilience in marine ecosystems.
Continue reading ‘Marine water acidification and coral bleaching’eCoral: how electrolysis could restore seawater conditions ideal for coral reefs
Published 9 December 2024 Science ClosedTags: chemistry, mitigation
Coral reefs suffer from climate change, including long-term ocean acidification (OA) and warming and short-term bleaching, tropical storms, and pollution events, all of which are increasing in frequency and severity. It is urgent yet unclear how to intervene to save coral reefs. Reversal of the ocean pH to preindustrial levels could restore coral reefs to their preindustrial growth rates; however, strategies to reverse OA on environmentally relevant scales have not been established. Anecdotally, electrolysis seems to help coral reefs recover from acidification and short-term events, but few uncontrolled studies support such claims. Here, using two independent continuum simulation approaches (COMSOL and CrunchFlow), we show the effect of electrolysis on seawater chemistry relevant to coral reef survival and growth. We conclude that near the negative electrodes, the cathodes, seawater pH, supersaturation, and carbonate concentration all increase significantly. Electrolysis of seawater, therefore, can be used to restore preindustrial ocean conditions locally to save coral reefs, an approach termed eCoral here. We anticipate these simulation results to be the starting point for controlled experiments to test whether seawater electrolysis promotes coral reef growth and restoration, as these simulations predict.
Continue reading ‘eCoral: how electrolysis could restore seawater conditions ideal for coral reefs’Climate resilience and profitability thresholds in chesapeake bay oyster aquaculture
Published 5 December 2024 Science ClosedTags: fisheries, mitigation, mollusks, North Atlantic, socio-economy
Highlights
- Climate change brings offsetting factors for oyster aquaculture.
- By 2068 we project slight profit declines for most locations.
- Optimized profits were driven more by site-to-site differences than future changes.
- Industry growth will be supported by making high quality areas available for leasing.
- Targeted mitigation strategies can boost profits even at high costs.
Abstract
Shellfish aquaculture producers in coastal systems are facing uncertain future growing conditions as climate change alters weather patterns and raises sea level. We examined expected mid-century (2059–2068) changes in aquaculture profitability from recent conditions by integrating models of climate change, estuarine hydrodynamics and biogeochemistry, oyster growth, oyster mortality, and economics, using the Chesapeake Bay, USA as a case study. We developed an economic stochastic dynamic programming (SDP) approach that generates optimal grower behavior to maximize profits under uncertainty by dynamically choosing planting density, replanting and mitigation use, in response to changing oyster stock status and water quality conditions. Separate models were developed for bottom culture largely serving the cannery market, and container culture largely serving the half-shell market, to reflect different production costs, market prices, and oyster growth and survival. The coupled hydrodynamic-biogeochemical and oyster ecology models projected high spatial variability in oyster growth and mortality with the most favorable growing conditions in the lower north and upper mid bay, where mortality is lowest, and the upper south bay, where growth is highest. Climate change by late mid-century generated modest water quality changes and virtually no mortality rate changes. Nonetheless, our modeling revealed that even if growers made optimal management choices under uncertainty, the majority of modeled sites would see a decline in profitability under climate change, primarily due to potential reductions in food availability. Bottom culture was more resilient to the future climate at most sites, being less sensitive to small changes in growth than container culture. Information on how aquaculture conditions currently vary in space was more important for profitability than future climate forecasts. Our stochastic dynamic programming approach tailored grower behavior to each site and unfolding annual conditions, including highly targeted and cost-effective mitigation adjustments to boost oyster survival or growth.
Continue reading ‘Climate resilience and profitability thresholds in chesapeake bay oyster aquaculture’The role of rolling corals and free-living calcifying coralline algae in the management of greenhouse gas CO2 in the Colombian Caribbean
Published 25 November 2024 Science ClosedTags: algae, biological response, BRcommunity, calcification, corals, dissolution, field, laboratory, mitigation, North Atlantic, photosynthesis, primary production, respiration
The ongoing increase in anthropogenic CO₂ emissions since the industrial revolution has accelerated ocean acidification (OA) by introducing CO₂ into seawater, forming carbonic acid and reducing pH levels. This acidification threatens marine calcifiers by weakening their capacity to build calcium carbonate structures and promoting the dissolution of existing skeletons. Nonetheless, calcifying organisms may contribute to mitigating OA effects. This study explores the roles of corals (rolling Siderastrea radians, a seagrass dweller) and free-living calcifying coralline algae (back reef) in CO₂ mitigation in seawater. Field experiments were conducted on Isla Grande (Corales del Rosario and San Bernardo National Natural Park, Colombian Caribbean), to observe the diel variations in photosynthesis and calcification of these uncommon reef builders across different times of the day. Results demonstrate diel shifts influenced by photosynthesis/respiration and calcification/dissolution, with free-living coralline algae exhibiting higher productivity and calcification rates than corals during the day. Notably, free-living coralline algae displayed pronounced hysteresis, reflecting high sensitivity to light. These findings underscore the significant role of free-living coralline algae in marine carbon cycling, suggesting a more substantial impact on CO₂ mitigation than previously recognized. Conserving free-living coralline algae and their habitats is thus critical for supporting marine ecosystem health and resilience amidst global change, warranting further research into their metabolic responses to inform conservation strategies.
Continue reading ‘The role of rolling corals and free-living calcifying coralline algae in the management of greenhouse gas CO2 in the Colombian Caribbean’Challenges and opportunities towards meeting the United Nations’ Sustainable Development Goals from coral and seaweed ecosystems in an era of climate change
Published 22 November 2024 Science ClosedTags: algae, biological response, corals, mitigation, policy, review, socio-economy
Global climate change scenarios due to anthropogenic responses jeopardize ecosystem sustainability and hinder progress toward achieving the United nations (UN-SDGs). Achieving “natural carbon solutions” from terrestrial ecosystems is challenging due to decreasing arable land and increasing marginal land. Marine ecosystems representing a wider “natural carbon solutions” have also been severely impacted by climate change. Among marine ecosystems, coral reefs and seaweed communities are the key ecosystem engineers that support a wide range of marine life, facilitate nutrient cycling, and provide essential ecosystem services with a pivotal role in sustaining coastal economies and livelihoods. Notably, these communities compete for space within the reef ecosystem and suffer from loss of diversity and richness due to climate change. Therefore, assessing the climate change resilience of both the corals and seaweeds is essential to evaluate and design long-term adaptation strategies, ecological innovations, and science-informed policies to conserve, restore, and sustainably manage economic services. This review article aims to highlight (1) the physiological response and resilience of corals and seaweeds to environmental changes, (2) the impact of climate change on their ecosystems and economic services, (3) their potential contributions towards the United Nations’ sustainable goals, (4) progressive efforts applied for their restoration, and (5) the potential complementary value of large-scale seaweed aquaculture as a carbon sink.
Continue reading ‘Challenges and opportunities towards meeting the United Nations’ Sustainable Development Goals from coral and seaweed ecosystems in an era of climate change’Experimental coral reef communities transform yet persist under mitigated future ocean warming and acidification
Published 31 October 2024 Science ClosedTags: biological response, BRcommunity, calcification, community composition, corals, laboratory, mesocosms, mitigation, molecular biology, mortality, multiple factors, otherprocess, temperature
Significance
Coral reefs are exceptional ecosystems and support hundreds of millions of people around the world, yet they are under severe threat due to ocean warming and acidification. Reefs are predicted to collapse over the next few decades under these climate change stressors, with grave consequences for society. Contrary to predictions of near total destruction, this study shows that with effective climate change mitigation, coral reefs will continue to change, but global reef collapse may still be avoidable.
Abstract
Coral reefs are among the most sensitive ecosystems affected by ocean warming and acidification, and are predicted to collapse over the next few decades. Reefs are predicted to shift from net accreting calcifier-dominated systems with exceptionally high biodiversity to net eroding algal-dominated systems with dramatically reduced biodiversity. Here, we present a two-year experimental study examining the responses of entire mesocosm coral reef communities to warming (+2 °C), acidification (−0.2 pH units), and combined future ocean (+2 °C, −0.2 pH) treatments. Contrary to modeled projections, we show that under future ocean conditions, these communities shift structure and composition yet persist as novel calcifying ecosystems with high biodiversity. Our results suggest that if climate change is limited to Paris Climate Agreement targets, coral reefs could persist in an altered state rather than collapse.
Continue reading ‘Experimental coral reef communities transform yet persist under mitigated future ocean warming and acidification’Sustainable Development Goal (SDG) 14.3.1 Indicator Quick Guide
Published 16 October 2024 Science ClosedTags: education, methods, mitigation, policy
Submitting data to assess OA globally
Background
In 2015, the United Nations adopted the 2030 Agenda and a set of Sustainable Development Goals (SDG), including a goal dedicated to the ocean, SDG 14, which calls to “conserve and sustainably use the oceans, seas, and marine resources for sustainable development”. Under this SDG 14, there are 10 Targets addressing a range of ocean issues and 10 Indicators, which are the measurable components of the Target. The Intergovernmental Oceanographic Commission (IOC) of UNESCO was identified as the custodian agency for the SDG Target 14.3: “Minimize and address the impacts of ocean acidification, including through enhanced scientific cooperation at all levels”, and the associated SDG Indicator 14.3.1 (“Average marine acidity (pH) measured at agreed suite of representative sampling stations”).
The SDG 14.3.1 Indicator Methodology provides the necessary guidance on how to conduct ocean acidification observation. The Methodology contains guidance on sampling strategy, measurement methods and calculation, methodology and instrumentation, links to community agreed Best Practices and Standard Operating Procedures, data quality categories and data quality control mechanism as well as recommendations for the calculation of the seawater carbonate system, including how to account for the uncertainty of measurements. It further offers support on how to and what kind of data sets to submit to IOC, to ensure the production of quality-controlled global and possibly regional products of surface ocean acidification.
The full text of the Methodology as well as the data template, the metadata template and the metadata instructions files can be downloaded from the SDG 14.3.1 Data Portal website (https://oa.iode.org/). The SDG 14.3.1 Data Portal is a tool for the submission, collection, validation, storage, and sharing of ocean acidification data and metadata submitted towards the SDG 14.3.1 Indicator.
This present document is an introduction to the SDG 14.3.1 Methodology, providing an introduction to some aspects of the guidance provided within the Methodology. This document should therefore not replace the Methodology; please make sure to read and apply the SDG 14.3.1 Methodology elaborated here.
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Assessing the potential of macroalgae-based carbon sequestration in Indonesia
Published 11 October 2024 Science ClosedTags: algae, biological response, Indian, laboratory, mitigation
Macroalgae are being intensively explored as a nature-based solution to address climate change. Although there are still some uncertainties about recognizing macroalgae in climate mitigation, the research trend on macroalgae carbon potential continues to increase. We collected secondary data, literature reviews, and expert opinions through focus group discussions to estimate the carbon sequestration potential of macroalgae and examine its feasibility in Indonesian climate mitigation. Our analysis shows that the carbon sequestration potential of macroalgae in Indonesia is significant, estimated to range from 351.246-2.526.332 Mg C yr−1, placing macroalgae as the third largest marine carbon store after mangroves and seagrass. In addition, macroalgae have higher CO2 sequestration rates than other blue carbon habitats. Our assessment of the viability of macroalgae in the blue carbon shows that macroalgae meet the critical elements of blue carbon criteria, including carbon sequestration scale, long-term storage, anthropogenic impact, and social or environmental interventions. However, aligning it with other climate mitigation policies is essential for macroalgae to be fully recognized in blue carbon. This preliminary study suggests that macroalgae could be necessary for Indonesia’s climate mitigation action.
Continue reading ‘Assessing the potential of macroalgae-based carbon sequestration in Indonesia’Linking cumulative carbon emissions to observable climate impacts
Published 10 October 2024 Science ClosedTags: globalmodeling, mitigation, modeling, policy, regionalmodeling, review
Anthropogenic CO2 emissions are causing climate change, and impacts of climate change are already affecting every region on Earth. The purpose of this review is to investigate climate impacts that can be linked quantitatively to cumulative CO2 emissions (CE), with a focus on impacts scaling linearly with CE. The reviewed studies indicate a proportionality between CE and various observable climate impacts such as regional warming, extreme daily temperatures, heavy precipitation events, seasonal changes in temperature and precipitation, global mean precipitation increase over ocean, sea ice decline in September across the Arctic Ocean, surface ocean acidification, global mean sea level rise, different marine heatwave characteristics, changes in habitat viability for non-human primates, as well as labour productivity loss due to extreme heat exposure. From the reviewed literature, we report estimates of these climate impacts resulting from one trillion tonne of CE (1 Tt C). These estimates are highly relevant for climate policy as they provide a way for assessing climate impacts associated with every amount of CO2 emitted by human activities. With the goal of expanding the number of climate impacts that could be linked quantitatively to CE, we propose a framework for estimating additional climate impacts resulting from CE. This framework builds on the transient climate response to cumulative emissions (TCRE), and it is applicable to climate impacts that scale linearly with global warming. We illustrate how the framework can be applied to quantify physical, biological, and societal climate impacts resulting from CE. With this review, we highlight that each tonne of CO2 emissions matters in terms of resulting impacts on natural and human systems.
Continue reading ‘Linking cumulative carbon emissions to observable climate impacts’A study on the governance pathways of the Law of the Sea in response to climate change
Published 3 October 2024 Science ClosedTags: mitigation, policy
The legal systems for ocean governance and climate change governance are based on the United Nations Convention on the Law of the Sea and the United Nations Framework Convention on Climate Change, respectively. However, due to differences in their negotiation backgrounds, legal scope, goals, and tasks, there is a lack of interaction between the two at the legal system level. The ocean plays a crucial role in regulating the Earth’s climate system, yet its value is often underestimated in the United Nations Framework Convention on Climate Change. The aim of this study is to analyze the effectiveness of the United Nations Convention on the Law of the Sea in addressing climate change. Specifically, we will examine the Convention’s ability to mitigate and adapt to climate change, and identify areas where it falls short, such as inadequate regulation of sea level rise, ocean acidification, and ocean fertilization. Based on this, proposals for governance paths from the perspective of the United Nations Convention on the Law of the Sea include developing the Agreement relating to the climate change and ocean governance and reinterpreting the United Nations Convention on the Law of the Sea in accordance with the Paris Agreement. The content should be adapted more flexibly to current climate change challenges, and provisions related to sea level rise and maritime boundaries should be reinterpreted to fill legal gaps. In addition, it is important to establish coordinated regulatory rules and framework agreements to address the issues of ocean fertilization and ocean acidification. Finally, to remedy the shortcomings in proving causation, scientific theories and due diligence obligations should be attributed. Through these measures, effective ocean law governance paths that address climate change can be explored.
Continue reading ‘A study on the governance pathways of the Law of the Sea in response to climate change’Experimental studies on CO2 sequestration via enhanced rock weathering in seawater: insights for climate change mitigation strategies in coastal and open ocean environments
Published 30 September 2024 Science ClosedTags: biogeochemistry, mitigation
Enhanced weathering (EW) of ultramafic rocks from the Muslim Bagh Ophiolite, Pakistan, has been studied in laboratory experiments to explore carbon sequestration as a climate change mitigation strategy for coastal and open sea environments. The research focused on a cost-effective ex situ experiment to examine the effects of EW reaction pathways arising from the interactions among rock powder, seawater and CO2. The experimental filtrates from different milled peridotite samples exhibit a decrease in the Mg/Ca ratio as the specific surface area increases, which accelerates reaction rates. This suggests that the leached Mg from the original rock may have been consumed in the formation of brucite, serpentine and carbonates during EW. Similar reaction pathways are also responsible for the chemical alterations observed in amphibolite, albeit to varying degrees. On the other hand, the experimental residues showed an increase in loss on ignition compared to the original rock, indicating that EW has facilitated the incorporation of H2O and CO2 into secondary mineral structures through various reaction pathways, leading to the formation of brucite, serpentine and carbonates. Thermal gravimetric analysis of the experimental residues confirms the presence of these minerals based on their decomposition temperatures. Additionally, XRD analysis identified a range of carbonates in the residues of both peridotite and amphibolite samples, validating the occurrence of carbonation reactions. SEM images reveal textural changes in both samples, supporting the formation of secondary minerals through EW, consistent with observations from the petrographic study of untreated samples. Control experiments on CO2 absorption in seawater showed a decrease in pH, highlighting ocean acidification from increased CO2 emissions. However, when rock powder was added to the seawater-CO2 mixture, the pH increased. This suggests that the EW of ultramafic rock powders can sequester CO2 while raising seawater pH through the formation of secondary minerals. This research could serve as an analog for EW applications, considering the worldwide abundance of ultramafic rocks and the availability of coastal and open ocean environments. However, further research is required to understand the behavior of other elements and their impacts on ocean chemistry in EW processes before applying CO2 sequestration strategies.
Continue reading ‘Experimental studies on CO2 sequestration via enhanced rock weathering in seawater: insights for climate change mitigation strategies in coastal and open ocean environments’Handbook of climate change mitigation and adaptation
Published 24 September 2024 Science ClosedTags: education, mitigation, policy, socio-economy
Overview
- Features new chapters on emerging technologies for climate change mitigation, including non-CO2-GHGs
- Comprehensively covers the impact of climate change
- Provides clear scientific rationale for the reality of climate change
About this book
Now in its 4th, extended edition, this completely revised and significantly expanded handbook addresses important new research findings and the global need for action related to climate change in its two most relevant aspects: mitigation and adaptation.
There is a growing consensus that anthropogenic activities have been driving global climate change, and the consequence will be catastrophic for civilization. Reducing the 37.1 billion metric tons of CO2 produced annually (2017 global emissions) along with other greenhouse gases, particularly methane, has become a leading grand challenge and the pursuit of sustainable energy, environments, and economies is a complex issue affecting the daily life of every citizen.
In this 4th edition, readers will find new chapters covering the causes and impacts of global warming, the climate change impacts on health, biodiversity, and the economy, and emerging technologies for climate change mitigation. Particular attention is given to topics such as wildfire threats, ocean acidification, coral bleaching, sea level rise, and permafrost thaw. The latest research on sustainable aviation fuels, carbon mineralization, and smart cities is also covered in this new edition, as well as topics like sustainable building design, climate-resistant building materials, and sustainable agriculture.
The Handbook of Climate Change Mitigation and Adaptation collates information in this multi-disciplinary area, providing readers with a comprehensive overview of the scientific background and current and emerging technologies. Intended for an interdisciplinary, global audience of researchers and decision-makers at universities and in industry, it covers climate change models; established, mature, and promising future technologies and ideas; the impact of climate change; strategies for dealing with global warming; the related political frameworks; and climate education.
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