Zooplankton grazing is the largest source of uncertainty for marine carbon cycling in CMIP6 models

Communications Earth & Environment, Journal Year: 2023, Volume and Issue: 4(1)

Published: June 14, 2023

Abstract The current generation of Earth system models used by the United Nations to project future climate scenarios (CMIP6) relies heavily on marine biogeochemical track fate carbon absorbed into oceans. Here we compare 11 CMIP6 and find largest source inter-model uncertainty in their representation cycle is phytoplankton-specific loss rates zooplankton grazing. This over three times larger than that net primary production driven large differences prescribed grazing dynamics. We run a controlled sensitivity experiment global model small changes dynamics (roughly 5% what across models) can increase secondary export 5 2 PgC yr −1 , respectively, even when tuned identical production, likely biasing predictions states food security.

Language: Английский

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Climate change and terrigenous inputs decrease the efficiency of the future Arctic Ocean’s biological carbon pump

Nature Climate Change, Journal Year: 2025, Volume and Issue: 15(2), P. 171 - 179

Published: Jan. 6, 2025

Abstract The Arctic experiences climate changes that are among the fastest in world and affect all Earth system components. Despite expected increase terrigenous inputs to Ocean, their impacts on biogeochemical cycles currently largely neglected IPCC-like models. Here we used a state-of-the-art high-resolution ocean biogeochemistry model includes carbon nutrient from rivers coastal erosion produce twenty-first-century pan-Arctic projections. Surprisingly, even with an anticipated rise primary production across wide range of emission scenarios, our findings indicate change will lead counterintuitive 40% reduction efficiency Arctic’s biological pump by 2100, which contribute 10%. Terrigenous also drive intense CO 2 outgassing, reducing Ocean’s sink at least 10% (33 TgC yr −1 ). These unexpected reinforced feedback, mostly due accelerated remineralization rates, lower capacity for sequestering carbon.

Language: Английский

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Severe 21st-century ocean acidification in Antarctic Marine Protected Areas

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Jan. 4, 2024

Antarctic coastal waters are home to several established or proposed Marine Protected Areas (MPAs) supporting exceptional biodiversity. Despite being threatened by anthropogenic climate change, uncertainties remain surrounding the future ocean acidification (OA) of these waters. Here we present 21st-century projections OA in MPAs under four emission scenarios using a high-resolution ocean-sea ice-biogeochemistry model with realistic ice-shelf geometry. By 2100, project pH declines up 0.36 (total scale) for top 200 m. Vigorous vertical mixing carbon produces severe throughout water column and existing MPAs. Consequently, end-of-century aragonite undersaturation is ubiquitous three highest scenarios. Given cumulative threat marine ecosystems environmental change activities such as fishing, our findings call strong emission-mitigation efforts further management strategies reduce pressures on ecosystems, continuation expansion

Language: Английский

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Twenty‐First‐Century Environmental Change Decreases Habitat Overlap of Antarctic Toothfish (Dissostichus mawsoni) and Its Prey

Global Change Biology, Journal Year: 2025, Volume and Issue: 31(2)

Published: Feb. 1, 2025

ABSTRACT Antarctic toothfish are a commercially exploited upper‐level predator in the Southern Ocean. As many of its prey, ectothermic, water‐breathing is specifically adapted to temperature and oxygen conditions present high‐latitude Additionally, life cycle depends on sea‐ice dynamics transport individuals by currents between regions with different prey. To assess impact 21st‐century climate change potential interactions we here employ extended aerobic growth index (AGI), which quantifies effect ocean levels habitat viability individual species. We quantify changes predator–prey viable overlap as obtained AGI. environmental data, use future projections for four emission scenarios from model FESOM‐REcoM, designed applications near continental shelf. For two highest‐emission scenarios, find that warming deoxygenation response cause subsurface decline up 40% important prey species, such silverfish icefish. Acknowledging regional differences, our results demonstrate alone can significantly perturb Our findings highlight need better quantitative understanding impacts species constrain ecosystem change.

Language: Английский

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Abruptly attenuated carbon sequestration with Weddell Sea dense waters by 2100

Nature Communications, Journal Year: 2022, Volume and Issue: 13(1)

Published: June 14, 2022

Abstract Antarctic Bottom Water formation, such as in the Weddell Sea, is an efficient vector for carbon sequestration on time scales of centuries. Possible changes under changing environmental conditions are unquantified to date, mainly due difficulties simulating relevant processes high-latitude continental shelves. Here, we use a model setup including both ice-shelf cavities and oceanic cycling demonstrate that by 2100, deep-ocean accumulation southern Sea abruptly attenuated only 40% 1990s rate high-emission scenario, while 2050s 2080s still 2.5-fold 4-fold higher, respectively, than 1990s. Assessing budgets water mass transformations, attribute this decline increased presence modified Warm Deep shelf, 16% reduction sea-ice 79% increase basal melt. Altogether, these lower density volume newly formed bottom waters reduce associated transport abyss.

Language: Английский

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Massive circumpolar biomass of Southern Ocean zooplankton: Implications for food web structure, carbon export, and marine spatial planning

Limnology and Oceanography, Journal Year: 2022, Volume and Issue: 67(11), P. 2516 - 2530

Published: Sept. 9, 2022

Abstract With rapid, sector‐specific climatic changes impacting the Southern Ocean, we need circumpolar‐scale biomass data of its plankton taxa to improve food web models, blue carbon budgets and resource management. Here, provide a new dataset on mesozooplankton with 2909 records spanning last 90 yr, describe, in comparable units, their circumpolar distribution alongside those phytoplankton, Antarctic krill, salps. our datasets, estimate total summer biomasses for phytoplankton (36 MT), (67 krill (30 salps (1.7 MT). The value is much higher than previously reported and, added that salps, points an enormous overall zooplankton Ocean. This means pyramids are often inverted, phytoplankton. Such high suggest key roles grazers nutrient cycling export ~ 50 Mt C yr −1 , solely from mortality overwintering typically reside at depth. Deep lipid respiration (the pump), example, would increase this even further. While inverted prevailed mid latitudes (50°–70°S), balance differed regionally: dominance by (highest Pacific sector), (Kerguelen Plateau), (north east Scotia Sea), (Crozet area). In light contrasting climate change impacts between these sectors, will underpin biogeochemical budgets, planning marine protected areas.

Language: Английский

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The Role of Zooplankton Grazing and Nutrient Recycling for Global Ocean Biogeochemistry and Phytoplankton Phenology

Journal of Geophysical Research Biogeosciences, Journal Year: 2022, Volume and Issue: 127(10)

Published: Oct. 1, 2022

Abstract Zooplankton plays a notable role in ocean biogeochemical cycles. However, it is often simulated as one generic group and top closure term models. This study presents the description of three zooplankton functional types (zPFTs, micro‐, meso‐ macrozooplankton) model FESOM‐REcoM. In presented model, microzooplankton fast‐growing herbivore group, mesozooplankton another major consumer phytoplankton, macrozooplankton slow‐growing with low temperature optimum. Meso‐ produce fast‐sinking fecal pellets. With zPFTs, annual mean biomass increases threefold to 210 Tg C. The new food web structure leads 25% increase net primary production 10% decrease export globally. Consequently, ratio decreases from 17% 12% model. zPFTs reduces mismatches observed dissolved inorganic nitrogen chlorophyll concentrations South Pacific Arctic Ocean, respectively. Representation also strongly affects phytoplankton phenology: Fast nutrient recycling by sustains higher summer autumn. Additional grazing delays start bloom 3 weeks controls magnitude peak Southern Ocean. As result, system switches light‐controlled Sverdrup dilution‐controlled Behrenfeld system. Overall, results suggest that representation multiple important capture underlying processes may shape response ecosystems ecosystem services on‐going future environmental change projections.

Language: Английский

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Knowledge Gaps in Quantifying the Climate Change Response of Biological Storage of Carbon in the Ocean

Earth s Future, Journal Year: 2024, Volume and Issue: 12(6)

Published: June 1, 2024

Abstract The ocean is responsible for taking up approximately 25% of anthropogenic CO 2 emissions and stores >50 times more carbon than the atmosphere. Biological processes in play a key role, maintaining atmospheric levels 200 ppm lower they would otherwise be. ocean's ability to take store sensitive climate change, however biological that contribute storage are uncertain, as how those will respond to, feedback on, change. As result, biogeochemical models vary widely their representation relevant processes, driving large uncertainties projections future storage. This review identifies affect may change three thematic areas: contributions alkalinity, net primary production, interior respiration. We undertook existing literature identify with high importance influencing biologically‐mediated ocean, prioritized on basis both an expert assessment community survey. Highly ranked survey were: alkalinity—high level understanding calcium carbonate production; production—resource limitation growth, zooplankton phytoplankton loss processes; respiration—microbial solubilization, particle characteristics type. analysis presented here designed support field or laboratory experiments targeting new process understanding, modeling efforts aimed at undertaking model development.

Language: Английский

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Climate drivers of Southern Ocean phytoplankton community composition and potential impacts on higher trophic levels

Frontiers in Marine Science, Journal Year: 2022, Volume and Issue: 9

Published: Aug. 11, 2022

Southern Ocean phytoplankton production supports rich Antarctic marine ecosystems comprising copepods, krill, fish, seals, penguins, and whales. Anthropogenic climate change, however, is likely to drive rearrangements in community composition with potential ramifications for the whole ecosystem. In general, communities dominated by large phytoplankton, i.e., diatoms, yield shorter, more efficient food chains than supported small phytoplankton. Guided a ensemble of Earth system model simulations run under high emission scenario (RCP8.5), we present hypotheses how anthropogenic change may shifts structure two regions Ocean: Circumpolar Current (ACC) region sea ice zone (SIZ). Though both experience warmer ocean temperatures increased advective iron flux 21st century warming, simulates proliferation diatoms at expense ACC, while opposite patterns are evident SIZ. The primary drivers simulated diatom increases ACC include supply, reduced light from cloudiness. contrast, reductions cover greater penetration SIZ, generating phenological advance bloom accompanied shift that effectively consume available iron; result an overall increase net production, but decreasing proportion diatoms. Changes this nature promote trophic energy transfer via copepods or krill region, ecosystem efficiency SIZ decline as grow dominance, possibly impacting webs sustaining predators. Despite simplistic representation our model, results point relative success contrasting ecological strategies different Ocean, higher levels.

Language: Английский

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Cascading effects augment the direct impact of CO2 on phytoplankton growth in a biogeochemical model

Elementa Science of the Anthropocene, Journal Year: 2022, Volume and Issue: 10(1)

Published: Jan. 1, 2022

Atmospheric and oceanic CO2 concentrations are rising at an unprecedented rate. Laboratory studies indicate a positive effect of on phytoplankton growth until optimum is reached, after which the negative impact accompanying acidification dominates. Here, we implemented carbonate system sensitivities into our global biogeochemical model FESOM-REcoM accounted explicitly for coccolithophores as group most sensitive to CO2. In idealized simulations in solely atmospheric mixing ratio was modified, changes competitive fitness biomass not only caused by direct effects CO2, but also indirect via nutrient light limitation well grazing. These cascading can both amplify or dampen responses changing ocean pCO2 levels. For example, coccolithophore negatively affected directly future indirectly limitation, these compensated weakened resulting from decrease small-phytoplankton biomass. Southern Ocean, decreases hereby preferred prey zooplankton, reduces grazing pressure diatoms allows them proliferate more strongly. that encompass CO2-driven warming acidification, reveals recent observed North Atlantic driven primarily Our results highlight change other environmental drivers growth, may play important role projections net primary production.

Language: Английский

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