Simulated Impact of Ocean Alkalinity Enhancement on Atmospheric CO₂ Removal in the Bering Sea

Earth s Future, Journal Year: 2022, Volume and Issue: 11(1)

Published: Dec. 19, 2022

Abstract Ocean alkalinity enhancement (OAE) has the potential to mitigate ocean acidification (OA) and induce atmospheric carbon dioxide (CO 2 ) removal (CDR). We evaluate CDR OA mitigation impacts of a sustained point‐source OAE 1.67 × 10 mol total (TA) yr −1 (equivalent 667,950 metric tons NaOH in Unimak Pass, Alaska. find elevation initially mitigates by decreasing p CO increasing aragonite saturation state pH. Then, enhanced air‐to‐sea exchange follows with an approximate e ‐folding time scale 5 weeks. Meaningful modeled reductions >10 μatm (or just under 0.02 pH units) extends 100–100,000 km around TA addition site. The efficiency (i.e., experimental seawater dissolved inorganic (DIC) increase divided maximum DIC expected from added TA) after first 3 years is 0.96 ± 0.01, reflecting essentially complete air‐sea adjustment additional TA. This high potentially unique feature Bering Sea related shallow depths mixed layer depths. ratio also (≥0.85) due content Sea. gas requires 3.6 months become (>95%) complete, so signal concentrations will likely be undetectable amid natural variability dilution mixing. therefore argue that modeling, on range scales, need play major role assessing interventions.

Language: Английский

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Status, Change, and Futures of Zooplankton in the Southern Ocean

Frontiers in Ecology and Evolution, Journal Year: 2022, Volume and Issue: 9

Published: June 17, 2022

In the Southern Ocean, several zooplankton taxonomic groups, euphausiids, copepods, salps and pteropods, are notable because of their biomass abundance roles in maintaining food webs ecosystem structure function, including provision globally important services. These groups consumers microbes, primary secondary producers, prey for fishes, cephalopods, seabirds, marine mammals. providing link between production, higher trophic levels these taxa influence energy flows, biological production biomass, biogeochemical cycles, carbon flux web interactions thereby modulating functioning ecosystems. Additionally, Antarctic krill ( Euphausia superba ) various fish species harvested by international fisheries. Global local drivers change expected to affect dynamics key species, which may have potentially profound wide-ranging implications Ocean ecosystems services they provide. Here we assess current understanding dominant metazoan within other euphausiid, copepod, salp pteropod species. We provide a systematic overview observed potential future responses changing functional relationships impact them. To support assessments conservation management strategies, also identify priorities research.

Language: Английский

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Pelagic calcium carbonate production and shallow dissolution in the North Pacific Ocean

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: Feb. 20, 2023

Abstract Planktonic calcifying organisms play a key role in regulating ocean carbonate chemistry and atmospheric CO 2 . Surprisingly, references to the absolute relative contribution of these calcium production are lacking. Here we report quantification pelagic North Pacific, providing new insights on three main planktonic groups. Our results show that coccolithophores dominate living (CaCO 3 ) standing stock, with coccolithophore calcite comprising ~90% total CaCO production, pteropods foraminifera playing secondary role. We is higher than sinking flux at 150 200 m stations ALOHA PAPA, implying large portion remineralised within photic zone; this extensive shallow dissolution explains apparent discrepancy between previous estimates derived from satellite observations/biogeochemical modeling versus sediment traps. suggest future changes cycle its impact will largely depend how poorly-understood processes determine whether zone or exported depth respond anthropogenic warming acidification.

Language: Английский

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Drivers of change in Arctic fjord socio-ecological systems: Examples from the European Arctic

Cambridge Prisms Coastal Futures, Journal Year: 2023, Volume and Issue: 1

Published: Jan. 1, 2023

Abstract Fjord systems are transition zones between land and sea, resulting in complex dynamic environments. They of particular interest the Arctic as they harbour ecosystems inhabited by a rich range species provide many societal benefits. The key drivers change European (i.e., Greenland, Svalbard, Northern Norway) fjord socio-ecological reviewed here, structured into five categories: cryosphere (sea ice, glacier mass balance, glacial riverine discharge), physics (seawater temperature, salinity, light), chemistry (carbonate system, nutrients), biology (primary production, biomass, richness), social (governance, tourism, fisheries). data available for past present state these drivers, well future model projections, analysed companion paper. Changes to two at base most interactions within fjords, seawater temperature will have significant profound consequences on fjords. This is because even though governance may be effective mitigating/adapting local disruptions caused changing climate, there possibly nothing that can done halt melting glaciers, warming waters, all downstream changes have. review provides first transdisciplinary synthesis systems. Knowledge what are, how interact with one another, should more expedient focus research needs adapting Arctic.

Language: Английский

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More Than Marine Heatwaves: A New Regime of Heat, Acidity, and Low Oxygen Compound Extreme Events in the Gulf of Alaska

AGU Advances, Journal Year: 2024, Volume and Issue: 5(1)

Published: Jan. 12, 2024

Abstract Recent marine heatwaves in the Gulf of Alaska have had devastating impacts on species from various trophic levels. Due to climate change, total heat exposure upper ocean has become longer, more intense, frequent, and likely happen at same time as other environmental extremes. The combination multiple extremes can exacerbate response sensitive organisms. Our hindcast simulation provides first indication that than 20% bottom water continental shelf was exposed quadruple heat, positive hydrogen ion concentration [H + ], negative aragonite saturation state (Ω arag ), oxygen [O 2 ] compound extreme events during 2018–2020 wave. Natural intrusion deep acidified combined with wave triggered occurrence these 2019. During 2013–2016 wave, surface waters were already widespread due temperature effect ]. We introduce a new Downwelling Index (GOADI) short‐term predictive skill, which serve indicator past near‐future Ω , near seafloor. results suggest waves may not been sole stressor led observed ecosystem warrant closer look existing situ inorganic carbon data biological observations model output.

Language: Английский

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The Combined Effects of Ocean Acidification and Respiration on Habitat Suitability for Marine Calcifiers Along the West Coast of North America

Journal of Geophysical Research Oceans, Journal Year: 2024, Volume and Issue: 129(4)

Published: April 1, 2024

Abstract The California Current Ecosystem (CCE) is a natural laboratory for studying the chemical and ecological impacts of ocean acidification. Biogeochemical variability in region due primarily to wind‐driven near‐shore upwelling cold waters that are rich re‐mineralized carbon poor oxygen. coastal regions exposed surface with increasing concentrations anthropogenic CO 2 (C anth ) from exchanges atmosphere shoreward transport mixing upwelled water. drives intense cycling organic matter created through photosynthesis degraded biological respiration subsurface habitats. We used an extended multiple linear‐regression approach determine spatial temporal C respired bio CCE based on cruise data 2007, 2011, 2012, 2013, 2016, 2021. Over region, accumulation rate increased 0.8 ± 0.1 μmol kg −1 yr northern latitudes 1.1 further south. rates decreased values about ∼0.3 at depths near 300 m. These correspond total pH decreases averaged 0.002 ‐1 ; whereas, aragonite saturation state ranged 0.006 0.011 . impact uptake was decrease amount oxygen consumption required cross critical thresholds (i.e., calcification, dissolution) marine calcifiers significantly lower recent cruises than pre‐industrial period because addition

Language: Английский

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Assessment framework to predict sensitivity of marine calcifiers to ocean alkalinity enhancement – identification of biological thresholds and importance of precautionary principle

Biogeosciences, Journal Year: 2025, Volume and Issue: 22(2), P. 473 - 498

Published: Jan. 28, 2025

Abstract. Ocean alkalinity enhancement (OAE), one of the marine carbon dioxide removal strategies, is gaining recognition in its ability to mitigate climate change and ocean acidification (OA). OAE based on adding open-ocean coastal systems through a variety different approaches, which raises carbonate chemistry parameters (such as pH, total alkalinity, aragonite saturation state) enhances uptake (CO2) from atmosphere. There are large uncertainties both short- long-term outcomes related potential environmental impacts, would ultimately have an influence social license success strategy. This paper represents synthesis effort, leveraging OA studies published data, observed patterns, generalizable responses. Our assessment framework was developed predict sensitivity calcifiers by using data originating studies. The done raw experimental 68 collected studies, covering 84 unique species capturing responses 11 biological groups (calcifying algae, corals, dinoflagellates, mollusks, gastropods, pteropods, coccolithophores, annelids, crustacean, echinoderms, foraminifera), regression analyses NaOH or Na2CO3 addition their respective thresholds. Predicted were categorized into six categories (linear positive negative, threshold parabolic neutral) delineate per species. results show that 34.4 % predicted be (N=33), 26.0 negative (N=25), 39.2 (N=38) neutral upon addition. For negatively impacted species, thresholds, 50 reduction calcification rate, range 500 µmol kg−1 Thus, we emphasize importance including much lower additions trials realistically evaluate situ However, it important note our do not consider equilibration with atmosphere thus only applicable short-term near-field application. primary goal research provide rates thresholds under / can serve tool for delineating risks. will help guide prioritize future regional monitoring efforts also aid communicating risks stakeholders. given fact at least some current approaches always assure safe space. With 60 being non-neutral, precautionary approach implementation warranted, identifying conditions where ecological could happen, key scaling up avoiding

Language: Английский

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Tracking the Space‐Time Evolution of Ocean Acidification Extremes in the California Current System and Northeast Pacific

Journal of Geophysical Research Oceans, Journal Year: 2022, Volume and Issue: 127(5)

Published: April 20, 2022

Abstract Ocean acidification is punctuated by episodic extremes of low pH and saturation state with regard to aragonite (Ω A ). Here, we use a hindcast simulation from 1984 2019 high‐resolution regional ocean model (ROMS‐BEC) identify track (OAX) in the northeast Pacific California current system (CCS). In first step, all grid‐cells whose Ω are simultaneously below their percentile over analysis period (1984–2019). second aggregate neighboring cells extreme conditions into three‐dimensional time evolving events, permitting us them Lagrangian manner lifetime. We detect more than 22 thousand events that occur at least once upper 100 m during lifetime, broad distributions terms size, duration, volume, intensity, 26% harboring corrosive < 1). By clustering OAXs, find three types CCS. Near coast, intense, shallow, short‐lasting OAXs dominate, caused strong upwelling. type consists large long‐lasting OAX associated westward propagating cyclonic eddies. They account for only 3% extremes, but most severe events. The third small depth arising pycnocline heave. potentially have deleterious effects on marine life. Marine calcifiers, such as pteropods, might be especially impacted conditions.

Language: Английский

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Modulation of ocean acidification by decadal climate variability in the Gulf of Alaska

Communications Earth & Environment, Journal Year: 2021, Volume and Issue: 2(1)

Published: Sept. 15, 2021

Abstract Uptake of anthropogenic carbon dioxide from the atmosphere by surface ocean is leading to global acidification, but regional variations in circulation and mixing can dampen or accelerate apparent acidification rates. Here we use a model simulation for years 1980 2013 observational data investigate how fluctuations impact rates waters Gulf Alaska. We find that large-scale atmospheric forcing influenced local winds upwelling strength, which turn affected rate. Specifically, variability wind stress curl depressed sea height subpolar gyre over decade-long intervals, increased nitrate- dissolved inorganic carbon-rich enhanced define this as Northern Alaska Oscillation suggest it cause extreme events are detrimental ecosystem health fisheries.

Language: Английский

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Dynamically downscaled projections of ocean acidification for the Bering Sea

Deep Sea Research Part II Topical Studies in Oceanography, Journal Year: 2022, Volume and Issue: 198, P. 105055 - 105055

Published: March 13, 2022

A regional ocean biogeochemical model for the Bering Sea is used to dynamically downscale three Earth System Models from CMIP5 archive under RCP 8.5 and 4.5 scenarios. These continuous runs, completed in conjunction with Alaska Climate Integrated Modeling Project (ACLIM), span 2006–2100 timeframe project continued warming, freshening, acidification (OA) shelf region over 21st Century, larger magnitude changes scenario. The downscaled projections suggest that annual average surface seawater aragonite saturation state (Ωarag) will decrease by 0.63–0.86 0.18–0.43 2100. Surface pH values 0.31–0.35 0.07–0.13 4.5. Seasonally, Ωarag < 1 conditions start emerge ∼2 months per year during winter between 2015 2030 both climate change Under 8.5, duration of these undersaturated grows ∼5 2100, occurring mid-October through mid-March. 4.5, remain constrained 2–3 In scenarios, summer maintain > due primary productivity, though maximum greatly reduced 8.5. Spatially, regions greatest decline are southeastern outer domain near break. Linear trends carbonate variables our simulations Model (ESM) output comparable indistinguishable compared spread. However, bottom water differ somewhat ESM simulations, latter more consistently resolving different domains. OA information provided can help inform biological sensitivity experiments longterm strategic planning marine fisheries management.

Language: Английский

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