Review and syntheses: Ocean alkalinity enhancement and carbon dioxide removal through marine enhanced rock weathering using olivine

Biogeosciences, Journal Year: 2025, Volume and Issue: 22(2), P. 355 - 384

Published: Jan. 21, 2025

Abstract. Marine enhanced rock weathering (mERW) is increasingly receiving attention as a marine-based carbon dioxide removal (CDR) technology. The method aims to achieve ocean alkalinity enhancement (OAE) by introducing fast-weathering rocks into coastal systems. latter envisioned act large natural biogeochemical reactor, where ambient physical and biological processes can stimulate dissolution, thus generating concomitant release increasing the seawater's capacity sequester CO2. Olivine has been put forward prime candidate mineral for mERW, but at present, no peer-reviewed results are available from larger-scale field studies in areas, so information about olivine dissolution marine systems largely derived laboratory experiments. As result, key uncertainties remain concerning efficiency, CO2 sequestration potential, impact of olivine-based mERW under relevant conditions. In this review, we summarize recent research advancements bridge gap between existing real-world environment which intended take place. To end, identify parameters that govern kinetics sediments associated enable us number still with respect implementation upscaling ERW, well monitoring, reporting, verification (MRV). From our analysis, conclude current knowledge base not sufficient predict outcome situ applications. Particularly, pore-water saturation on rate question additionality generation critical unknowns. more confidently assess potential dedicated pilot conditions needed, should be conducted sufficiently spatial scale monitored long enough time temporal resolution. Additionally, analysis indicates specific sediment type application site (e.g., cohesive versus permeable) will factor applications, it significantly influencing pH, dynamics, generation. Therefore, future also target different types.

Language: Английский

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Climate targets, carbon dioxide removal, and the potential role of ocean alkalinity enhancement

State of the Planet, Journal Year: 2023, Volume and Issue: 2-oae2023, P. 1 - 9

Published: Nov. 27, 2023

Abstract. The Paris Agreement to limit global warming well below 2 ∘C requires the ambitious reduction in greenhouse gas emissions and balancing of remaining through carbon sinks (i.e., deployment dioxide removal or CDR). While climate mitigation scenarios until now primarily consider land-based CDR methods, there is growing concern about their potential deliver sufficient CDR, marine options are receiving more interest. Based on idealized theoretical studies, ocean alkalinity enhancement (OAE) appears as a promising method. However, knowledge base insufficient for robust assessment its practical feasibility, side effects, social governance aspects, monitoring verification issues. A number research efforts aims improve this timely manner. We provide an overview current situation developing OAE method describe history that has led creation best practices guide.

Language: Английский

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The additionality problem of ocean alkalinity enhancement

Biogeosciences, Journal Year: 2024, Volume and Issue: 21(1), P. 261 - 277

Published: Jan. 16, 2024

Abstract. Ocean alkalinity enhancement (OAE) is an emerging approach for atmospheric carbon dioxide removal (CDR). The net climatic benefit of OAE depends on how much it can increase CO2 sequestration relative to a baseline state without OAE. This so-called “additionality” be calculated as follows: Additionality=COAE-ΔCbaseline. So far, feasibility studies have mainly focussed enhancing in the oceans stimulate (COAE); however, primary focus has not been such anthropogenic would modify natural cycle and associated (ΔCbaseline). Here, I present incubation experiments which materials considered (sodium hydroxide, steel slag, olivine) are exposed beach sand investigate influence sources sinks. show that strongly reduce generation alkalinity, thereby reducing additionality. because increases calcium carbonate saturation state, reduces dissolution from sand, source. argue this “additionality problem” potentially widespread applies many marine systems where implementation – far beyond scenario investigated study. However, problem mitigated by dilute dosing into ocean environment avoidance cycling hotspots, sediments. Understanding potential slowdown through introduction will crucial assessment

Language: Английский

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Growth response of Emiliania huxleyi to ocean alkalinity enhancement

Biogeosciences, Journal Year: 2025, Volume and Issue: 22(2), P. 405 - 415

Published: Jan. 22, 2025

Abstract. The urgent necessity of reducing greenhouse gas emissions is coupled with a pressing need for widespread implementation carbon dioxide removal (CDR) techniques to limit the increase in mean global temperature levels below 2 °C compared pre-industrial times. One proposed CDR method, ocean alkalinity enhancement (OAE), mimics natural rock weathering processes by introducing suitable minerals into ocean, thereby increasing and promoting CO2 chemical absorption. While theoretical studies hold promise OAE as climate mitigation strategy, careful consideration its ecological implications essential. Indeed, impact enhanced on marine organisms remains subject investigation, it may lead changes species composition. implicates favorable conditions calcifying enhancing saturation state calcium carbonate decreasing energetic costs calcification. This affect primary production improving phytoplankton, among which coccolithophores play leading role. They contribute < 10 % but are responsible large proportion calcite deposition. previous research has extensively studied effects acidification coccolithophores, fewer have explored impacts elevated pH alkalinity. In this context, we sensitivity Emiliania huxleyi, most coccolithophore species, culture experiment. We monitored species' growth calcification response progressively total (TA). Above change (ΔTA) ∼ 600 µmol kg−1, concentrations decreased, E. huxleyi rate diminished, suggesting threshold concentration 100 µatm necessary optimal growth. cellular organic ratio (PIC : POC) remained stable over range. Due enhancement, formation was lower. rapidly advancing already reached field-testing stage. Hence, our study contributes critical part investigations required comprehend potential biological before large-scale adopted.

Language: Английский

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A systematic analysis of operating parameters for CO2 capture from seawater by Bipolar Membrane Electrodialysis (BPMED)

Separation and Purification Technology, Journal Year: 2024, Volume and Issue: 339, P. 126679 - 126679

Published: Feb. 4, 2024

Language: Английский

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Investigating the effect of silicate- and calcium-based ocean alkalinity enhancement on diatom silicification

Biogeosciences, Journal Year: 2024, Volume and Issue: 21(11), P. 2777 - 2794

Published: June 12, 2024

Abstract. Gigatonne-scale atmospheric carbon dioxide removal (CDR) will almost certainly be needed to supplement the emission reductions required keep global warming between 1.5–2 °C. Ocean alkalinity enhancement (OAE) is an emerging marine CDR method with addition of pulverised minerals surface ocean being one widely considered approach. A concern this approach potential for dissolution products released from impact phytoplankton communities. We conducted experiment 10 pelagic mesocosms (M1–M10) in Raunefjorden, Bergen, Norway, assess implications simulated silicate- and calcium-based mineral OAE on a coastal plankton community. Five (M1, M3, M5, M7, M9) were enriched silicate (∼ 75 µmol L−1 Na2SiO3), along gradient 0 ∼ 600 kg−1, magnesium proportion additions. The other five (M2, M4, M6, M8, M10) same calcium explored many components community, microbes fish larvae, here we report influence based diatom silicification. Macronutrients (nitrate phosphate) limited silicification at onset until nutrient additions day 26. Silicification was significantly greater silicate-based treatment, all genera except Cylindrotheca displaying increase as result increased concentration dissolved silicate. In contrast effect differences concentrations two treatments, increases only influenced genera, Pseudo-nitzschia Nitzschia. four (Arcocellulus, Cylindrotheca, Skeletonema, Thalassiosira) investigated displayed no significant changes kg−1 above natural levels. summary, our findings illustrate that via methods has genus-specific impacts diatoms. This research underscores importance understanding full breadth different approaches, their risks, co-benefits, interactive effects.

Language: Английский

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Pathways for marine carbon dioxide removal using electrochemical acid-base generation

Frontiers in Climate, Journal Year: 2024, Volume and Issue: 6

Published: April 12, 2024

Research over the past decade has resulted in various methods for removing CO 2 from atmosphere using seawater and electrochemically generated acids bases. This Perspective aims to present a unified framework comparing these approaches. Specifically, can all be seen as falling into one of two categories: those that result net increase ocean alkalinity use “ocean sponge” atmospheric (ocean enhancement, or OAE) cycle pump” cycling, OAC). In this Perspective, approaches marine carbon dioxide removal (mCDR) electrochemistry are compared framework, similarities differences categories explored.

Language: Английский

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Assessing the impact of CO₂-equilibrated ocean alkalinity enhancement on microbial metabolic rates in an oligotrophic system

Biogeosciences, Journal Year: 2024, Volume and Issue: 21(11), P. 2859 - 2876

Published: June 13, 2024

Abstract. Ocean alkalinity enhancement (OAE) is a negative emissions technology (NET) that shows significant potential for climate change mitigation. By increasing the bicarbonate ion concentration in ocean water, OAE could enhance long-term carbon storage and mitigate acidification. However, side effects and/or co-benefits of on natural planktonic communities remain poorly understood. To address this knowledge gap, mesocosm experiment was conducted oligotrophic waters Gran Canaria. A CO2-equilibrated total (TA) gradient employed increments 300 µmol L−1, ranging from ∼ 2400 to 4800 L−1. This study represents first attempt evaluate impacts under conditions. The results show net community production (NCP), gross (GP), respiration (CR) rates, metabolic balance (GP:CR) did not exhibit linear response whole gradient. Instead, polynomial regression models were observed all rates up ΔTA 1800 relation dissolved inorganic (DIC) concentrations. Notably, 1500 L−1 treatments showed peaks NCP shifting heterotrophic an autotrophic state, with values 4 8 O2 kg−1 d−1, respectively. These optimum curve also reflected nanoplankton abundance, size-fractionated chlorophyll a, 14C uptake data. Furthermore, abiotic precipitation occurred highest treatment after day 21, but no impact measured parameters detected. Overall, damaging effect range applied here phytoplankton primary production, metabolism, composition be inferred. In fact, co-benefit form positive curvilinear DIC treatment. Further experimental research at scale key gain better understanding short- communities.

Language: Английский

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Seafloor alkalinity enhancement as a carbon dioxide removal strategy in the Baltic Sea

Communications Earth & Environment, Journal Year: 2024, Volume and Issue: 5(1)

Published: Aug. 21, 2024

Abstract Carbon dioxide removal from the atmosphere and storage over long times scales in terrestrial marine reservoirs is urgently needed to limit global warming for sustainable management of carbon cycle. Ocean alkalinity enhancement by artificial addition carbonate minerals seafloor has been proposed as a method sequester atmospheric CO 2 store it ocean dissolved bicarbonate. Here, reaction-transport model used scrutinize efficacy calcite dissolution at well-studied site southwestern Baltic Sea – brackish coastal water body northern Europe. We find that most simply buried without under moderate rates. Applying other sites suggests rates efficiencies are higher areas with low salinity undersaturated bottom waters. A simple box predicts tentative net uptake rate 3.2 megatonnes per year wider after continually adding muddy sediments 10 years. More robust estimates now require validation field studies.

Language: Английский

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Potential Environmental Impacts and Management Strategies for Metal Release during Ocean Alkalinity Enhancement Using Olivine

Environmental Science & Technology, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 8, 2025

Ocean alkalinity enhancement (OAE) based on enhanced weathering of olivine (EWO) is a promising marine carbon dioxide removal (mCDR) technique. Previous research primarily focuses the toxicological effects potentially toxic metals (PTMs) released from olivine. In this Perspective, we explore overlooked impacts EWO environmental media in two scenarios: applied to beaches/shallow continental shelves and offshore dispersion by vessels. We analyze potential migration pathways iron PTMs (e.g., nickel chromium) after their release, interactions with manganese oxides sediments, causing secondary contamination. Additionally, propose mitigation strategies prevent PTM concentrations exceeding local quality standards, including use alkalization equipment control levels. This Perspective underscores need for thorough assessments prior large-scale implementation ensure sustainability efficacy mCDR efforts.

Language: Английский

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