The microbial carbon pump and climate change

Nature Reviews Microbiology, Journal Year: 2024, Volume and Issue: 22(7), P. 408 - 419

Published: March 15, 2024

Language: Английский

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Monitoring, reporting, and verification for ocean alkalinity enhancement

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

Published: Nov. 27, 2023

Abstract. Monitoring, reporting, and verification (MRV) refers to the multistep process of monitoring amount greenhouse gas removed by a carbon dioxide removal (CDR) activity reporting results third party. The party then verifies results. While MRV is usually conducted in pursuit certification voluntary or regulated CDR market, this chapter focuses on key recommendations for relevant ocean alkalinity enhancement (OAE) research. Early stage OAE research may become foundation which markets are built. Therefore, such carries special obligation toward comprehensiveness, reproducibility, transparency. Observational approaches during field trials should aim quantify delivery seawater monitor secondary precipitation, biotic calcification, other ecosystem changes that can feed back sources sinks gases where measurably elevated. Observations resultant shifts partial pressure CO₂ (pCO₂) pH help determine efficacy amenable autonomous monitoring. However, because turbulent energetic equilibration between atmosphere take several months longer, added will be diluted perturbation levels undetectable above background variability timescales MRV. comprehensive quantification via impossible through observational methods alone, numerical simulations required. development fit-for-purpose models, carefully validated against data, critical part OAE.

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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Responses of globally important phytoplankton species to olivine dissolution products and implications for carbon dioxide removal via ocean alkalinity enhancement

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2023, Volume and Issue: unknown

Published: April 9, 2023

Abstract Anthropogenic greenhouse gas emissions are leading to global temperature increases, ocean acidification, and significant ecosystem impacts. Given current trajectories, the IPCC reports indicate that rapid abatement of CO 2 development carbon dioxide removal (CDR) strategies needed address legacy difficult abate sources. These CDR methods must efficiently safely sequester gigatons atmospheric . Coastal Enhanced Weathering (CEW) via addition common mineral olivine coastal waters is one promising approach enhance alkalinity for large-scale CDR. As weathers, it releases several biologically active dissolution products, including alkalinity, trace metals, nutrient silicate. Released metals can serve as micronutrients but may also be toxic at high concentrations marine biota phytoplankton lie base food webs. We grew six species representing globally important under elevated products a synthetic leachate (OL) based on elemental composition. monitored their physiological biogeochemical responses, which allowed us determine impacts thresholds concentrations, in individual effects specific constituents. found both positive neutral responses no evident two silicifying diatoms, calcifying coccolithophore, three cyanobacteria. In single competitive co-cultures, silicifiers calcifiers benefited from like iron silicate or enhanced respectively. The non-N -fixing picocyanobacterium could use olivine-derived growth, while N cyanobacteria not. However, other nickel cobalt supported cyanobacterial growth across groups. Growth benefits groups situ will depend species-specific ambient required nutrients. Results suggest appear unlikely cause negative any examined, even support particular taxa some conditions. Future studies shed light long-term eco-evolutionary exposure potential microbes turn have rates regional biogeochemistry.

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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Responses of globally important phytoplankton species to olivine dissolution products and implications for carbon dioxide removal via ocean alkalinity enhancement

Biogeosciences, Journal Year: 2023, Volume and Issue: 20(22), P. 4669 - 4682

Published: Nov. 27, 2023

Abstract. Anthropogenic greenhouse gas emissions are leading to global temperature increases, ocean acidification, and significant ecosystem impacts. Given current trajectories, the IPCC's reports indicate that rapid abatement of CO2 development carbon dioxide removal (CDR) strategies needed address legacy difficult-to-abate sources. These CDR methods must efficiently safely sequester gigatons atmospheric CO2. Coastal enhanced weathering (CEW) via addition common mineral olivine coastal waters is one promising approach enhance alkalinity for large-scale CDR. As weathers, it releases several biologically active dissolution products, including alkalinity, trace metals, nutrient silicate. Released metals can serve as micronutrients but may also be toxic at high concentrations marine biota, phytoplankton, which lie base food webs. We grew six species representing globally important phytoplankton under elevated products a synthetic leachate (OL) based on olivine's elemental composition. monitored their physiological biogeochemical responses, allowed us determine impacts thresholds concentrations, in individual effects specific constituents. found both positive neutral responses no evident two silicifying diatoms, calcifying coccolithophore, three cyanobacteria. In single competitive co-cultures, silicifiers calcifiers benefited from like iron silicate or respectively. The non-N2-fixing picocyanobacterium could use olivine-derived growth, while N2-fixing cyanobacteria not. However, other nickel cobalt supported cyanobacterial growth across groups. Growth benefits groups situ will depend species-specific ambient required nutrients. Results suggest appear unlikely cause negative any examined, even support particular taxa some conditions. Future studies shed light long-term eco-evolutionary exposure potential microbes turn have rates regional biogeochemistry.

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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Particle fluxes by subtropical pelagic communities under ocean alkalinity enhancement

Biogeosciences, Journal Year: 2025, Volume and Issue: 22(1), P. 71 - 86

Published: Jan. 8, 2025

Abstract. Ocean alkalinity enhancement (OAE) has been proposed as a carbon dioxide removal technology (CDR), allowing for long-term storage of in the ocean. By changing carbonate speciation seawater, OAE may potentially alter marine ecosystems with implications biological pump. Using mesocosms subtropical North Atlantic, we provide first empirical insights into impacts carbonate-based on vertical flux and attenuation sinking particles an oligotrophic plankton community. We enhanced total (TA) increments 300 µmol kg−1, reaching up to ΔTA = 2400 kg−1 compared ambient TA. applied pCO2-equilibrated approach; i.e., dissolved inorganic (DIC) was raised simultaneously TA maintain seawater pCO2 equilibrium atmosphere, thereby keeping perturbations chemistry moderate. The major elements, including carbon, nitrogen, phosphorus, silicon, well their stoichiometric ratios (e.g., carbon-to-nitrogen ratios), remained unaffected over 29 d OAE. particle properties controlling attenuation, velocities remineralization rates, also by However, observed abiotic mineral precipitation at high levels (ΔTA 1800 higher) that resulted substantial increase particulate (PIC) formation. associated consumption reduces efficiency CO2 emphasizes importance maintaining within carefully defined operating range. Our findings suggest export communities is insensitive using pre-equilibrated approach. integrity ecosystem services prerequisite large-scale application should be further tested across variety nutrient regimes less idealized approaches.

Language: Английский

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Assessing the impacts of simulated ocean alkalinity enhancement on viability and growth of nearshore species of phytoplankton

Biogeosciences, Journal Year: 2025, Volume and Issue: 22(2), P. 499 - 512

Published: Jan. 28, 2025

Abstract. Over the past 250 years, atmospheric CO2 concentrations have risen steadily from 277 to 405 ppm, driving global climate change. In response, new tools are being developed remove carbon atmosphere using negative emission technologies (NETs), in addition reducing anthropogenic emissions. One proposed NET is ocean alkalinity enhancement (OAE), which artificially raising favours formation of bicarbonate CO2, leading a decrease partial pressure water. Subsequent invasion results net sequestration carbon. The aim this study was investigate impact simulated OAE, through alteration pH, on phytoplankton representative spring and fall blooms nearshore, temperate waters. potential impacts OAE were assessed (1) an analysis prior studies investigating effects elevated pH growth rates (2) experimental assessment short-term (10 min) long-term (8 d) elevation viability subsequent two nearshore species phytoplankton. Viability with modified serial dilution culture–most probable number assay. Chlorophyll fluorescence used test for changes photosynthetic competence apparent rates. There no significant or diatom Thalassiosira pseudonana prymnesiophyte Diacronema lutheri (formerly Pavlova lutheri) exposure pH. However, there Short-term anticipated more closely mirror natural systems land-based will be implemented because system flushing dilution. indicates wide variability response within between taxonomic groups, about 50 % expected not impacted by increase unequilibrated mineral-based OAE. To extent that responses reflect (largely unreported) parallel reductions dissolved inorganic (DIC) availability, susceptibility may reduced ingassing prevented.

Language: Английский

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