Shallow Calcium Carbonate Cycling in the North Pacific Ocean

Global Biogeochemical Cycles, Journal Year: 2022, Volume and Issue: 36(5)

Published: May 1, 2022

Abstract The cycling of biologically produced calcium carbonate (CaCO 3 ) in the ocean is a fundamental component global carbon cycle. Here, we present experimental determinations situ coccolith and foraminiferal calcite dissolution rates. We combine these rates with solid phase fluxes, dissolved tracers, historical data to constrain alkalinity cycle shallow North Pacific Ocean. coccolithophores demonstrate nonlinear dependence on saturation state. Dissolution all three major calcifying groups (coccoliths, foraminifera, aragonitic pteropods) are too slow explain patterns both CaCO sinking flux regeneration Pacific. Using combination solid‐phase document significant signal seawater supersaturated for calcite. Driving ambient state oxygen consumption simultaneously explains profiles across entire N. basin. do not need invoke presence phases higher solubilities. Instead, biomineralization metabolic processes intimately associate acid (CO 2 base same particles, driving coupled remineralization organic . linkage likely occurs through due zooplankton grazing microbial aerobic respiration within degrading particle aggregates. coupling cycles acts as filter export inorganic deep ocean.

Language: Английский

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Aragonite dissolution protects calcite at the seafloor

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

Published: March 1, 2022

Abstract In the open ocean, calcium carbonates are mainly found in two mineral forms. Calcite, least soluble, is widespread at seafloor, while aragonite, more rarely preserved marine sediments. Despite its greater solubility, research has shown that whose contribution to global pelagic calcification could be par with of calcite, able reach deep-ocean. If large quantities aragonite settle and dissolve this represents a source alkalinity buffers deep ocean favours preservation less soluble acting as deep-sea, carbonate version galvanization. Here, we investigate role dissolution on early diagenesis calcite-rich sediments using novel 3D, micrometric-scale reactive-transport model combined X-ray tomography structures natural calcite shells. Results highlight important diffusive transport benthic dissolution, agreement recent work. We show that, locally, fluxes seafloor sufficient suppress top layer seabed, possibly causing recrystallization. As producers particularly vulnerable acidification, proposed galvanizing effect weakened future, sediment-water interface will have cover share CO 2 neutralization.

Language: Английский

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Quantitative and mechanistic understanding of the open ocean carbonate pump - perspectives for remote sensing and autonomous in situ observation

Earth-Science Reviews, Journal Year: 2023, Volume and Issue: 239, P. 104359 - 104359

Published: Feb. 18, 2023

The open ocean carbonate pump represents the production and downward flux of particulate inorganic carbon (PIC) in form calcium synthesized by calcifying plankton. This operates alongside organic pump, which concerns carbon, mostly particles (POC). While draws down atmospheric dioxide, causes an increase surface dioxide (CO2), thereby counteracting pump. However, PIC produced is high-density has been hypothesized to enhance increasing efficiency Here, we review our current quantitative mechanistic understanding contemporary its counter- ballast effects. We first examine relative contributions various plankton groups (coccolithophores, foraminifera, pteropods) based on a global compilation observations. Next, compare spatial patterns calcification rates from remote sensing with observations at depth obtained sediment traps radiochemical tracers. then estimates counter effect partial pressure CO2, pCO2, waters studies rain ratio exported amount CO2 released per precipitated, Ψ. implementations biogeochemical models. Lastly, discuss autonomous BioGeoChemical-Argo (BGC-Argo) profiling floats perspectives for extending

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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The representation of alkalinity and the carbonate pump from CMIP5 to CMIP6 Earth system models and implications for the carbon cycle

Biogeosciences, Journal Year: 2023, Volume and Issue: 20(7), P. 1195 - 1257

Published: April 3, 2023

Abstract. Ocean alkalinity is critical to the uptake of atmospheric carbon in surface waters and provides buffering capacity towards associated acidification. However, unlike dissolved inorganic (DIC), not directly impacted by anthropogenic emissions. Within context projections future ocean potential ecosystem impacts, especially through Coupled Model Intercomparison Projects (CMIPs), representation main driver its distribution interior, calcium carbonate cycle, have often been overlooked. Here we track changes from CMIP5 CMIP6 with respect Earth system model (ESM) pump which depletes biological production releases it at depth export dissolution. We report an improvement ESMs relative those CMIP5, simulating lower concentrations, increased meridional gradient enhanced global vertical gradient. This can be explained part increase (CaCO3) for some ESMs, redistributes strengthens water column. were able constrain a particulate (PIC) estimate 44–55 Tmol yr−1 100 m match observed alkalinity. Reviewing CaCO3 cycle across CMIP5/6, find substantial range parameterizations. While all biogeochemical models currently represent pelagic calcification, they do so implicitly, benthic calcification. In addition, most simulate marine calcite but aragonite. CMIP6, certain groups complexity simulated production, sinking, dissolution sedimentation. this insufficient explain overall representation, therefore likely result biogeochemistry tuning or ad hoc Although modellers aim balance budget order limit drift under pre-industrial conditions, varying assumptions related closure and/or initialization procedure influence uptake. For instance, many models, burial are independent seawater saturation state, when considered, sensitivities substantial. As such, impact acidification on pump, turn uptake, potentially underestimated current insufficiently constrained.

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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Microfacies shift in the Late Paleocene–Early Eocene Patala Formation in the Upper Indus Basin (Pakistan): Implications for development of the Ceno-Tethys Ocean

Marine and Petroleum Geology, Journal Year: 2024, Volume and Issue: 161, P. 106693 - 106693

Published: Jan. 11, 2024

Language: Английский

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Calcium carbonate cycling in the Southern Ocean: insights from dissolved calcium and potential alkalinity tracers

Limnology and Oceanography Letters, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 10, 2025

Abstract The cycling of calcium carbonate (CaCO 3 ) plays a significant role in deep‐water carbon sequestration and affects the buffer capacity upper ocean for absorbing atmospheric CO 2 . This study investigates dissolved (Ca) potential alkalinity (PA) as tracers CaCO Southern Ocean. correlation between PA Ca concentrations subantarctic polar waters supports their use effective process dissolution precipitation. Estimates particulate inorganic export flux based on concentration reveals substantial contributions Ocean, with higher values waters. These findings highlight value understanding its buffering

Language: Английский

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Towards CO2 emissions reduction of shipping: Ca(OH)2 based carbon capture system for safeguarding the marine environment

Frontiers in Marine Science, Journal Year: 2025, Volume and Issue: 12

Published: Feb. 7, 2025

Climate change poses a global challenge related to the reduction of pollutant atmospheric emissions and maritime transportation sector is directly involved, due its significant impact on production Greenhouse Gases other substances. While established technologies have effectively targeted like Nitrogen Oxides (NO X ) Sulfur (SO ), persistence Carbon dioxide (CO 2 represents an ongoing concern. Novel targeting CO been lately studied proposed for inland applications, are now being developed applications. With this regard, present study explores potential Capture Systems (CCS) mitigate produced by cargo ships. implementation CCS faces challenges, including space limitations logistical complexities, possible integration onboard marks step in fight against climate change. The authors propose innovative approach using Calcium Hydroxide Ca(OH) based CCS, offering dual benefit resolution ocean acidification through carbonate (CaCO 3 final product resulting from capture process. Additionally, examines feasibility generated reuse industry, promoting circular economy addressing environmental issues. This solution underscores urgent need transformative measures reduce emissions, line with efforts safeguarding marine environment combat

Language: Английский

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Integrated Assessment of Ocean Acidification Risks to Pteropods in the Northern High Latitudes: Regional Comparison of Exposure, Sensitivity and Adaptive Capacity

Frontiers in Marine Science, Journal Year: 2021, Volume and Issue: 8

Published: Sept. 10, 2021

Exposure to the impact of ocean acidification (OA) is increasing in high-latitudinal productive habitats. Pelagic calcifying snails (pteropods), a significant component diet economically important fish, are found high abundance these regions. Pteropods have thin shells that readily dissolve at low aragonite saturation state (Ω ar ), making them susceptible OA. Here, we conducted first integrated risk assessment for pteropods Eastern Pacific subpolar gyre, Gulf Alaska (GoA), Bering Sea, and Amundsen Gulf. We determined pteropod populations by integrating measures OA exposure, biological sensitivity, resilience. was based on physical-chemical hydrographic observations regional biogeochemical model outputs, delineating seasonal decadal changes carbonate chemistry conditions. Biological sensitivity morphometrics shell-building processes, including shell dissolution, density thickness. Resilience adaptive capacity were species diversity spatial connectivity, derived from particle tracking modeling. Extensive dissolution central western part parts identified two distinct morphotypes: L. helicina pacifica , with high-spired flatter shells, respectively. Despite presence different morphotypes, genetic analyses mitochondrial haplotypes single species, without differentiation between morphological forms, coinciding evidence widespread connectivity. morphometric characteristics depends omega ); under Ω decline, build thicker which indicative certain level phenotypic plasticity. An evaluation multiple approaches assumes population persistence intensification latitude eastern North because their known vulnerability, along limited despite connectivity our current lack sufficient knowledge capacity. Such comprehensive understanding would permit improved prediction ecosystem change relevant effective fisheries resource management, as well more robust foundation monitoring health investigating impacts

Language: Английский

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