The Oxalate-Carbonate Pathway: A Reliable Sink for Atmospheric CO2 Through Calcium Carbonate Biomineralization in Ferralitic Tropical Soils

2011 ◽  
pp. 191-199 ◽  
Author(s):  
Michel Aragno ◽  
Eric Verrecchia
Keyword(s):  
Calcium Carbonate ◽  
Tropical Soils ◽  
Atmospheric Co2

scholarly journals Calcium carbonate corrosivity in an Alaskan inland sea

2014 ◽  
Vol 11 (2) ◽  
pp. 365-379 ◽  
Author(s):  
W. Evans ◽  
J. T. Mathis ◽  
J. N. Cross
Keyword(s):  
Calcium Carbonate ◽  
Focal Point ◽  
Point Sources ◽  
Atmospheric Co2 ◽  
Co2 Uptake ◽  
Mode Water ◽  
Tidewater Glaciers ◽  
South Central ◽  
System Data ◽  
Shell Forming

Abstract. Ocean acidification is the hydrogen ion increase caused by the oceanic uptake of anthropogenic CO2, and is a focal point in marine biogeochemistry, in part, because this chemical reaction reduces calcium carbonate (CaCO3) saturation states (Ω) to levels that are corrosive (i.e., Ω ≤ 1) to shell-forming marine organisms. However, other processes can drive CaCO3 corrosivity; specifically, the addition of tidewater glacial melt. Carbonate system data collected in May and September from 2009 through 2012 in Prince William Sound (PWS), a semienclosed inland sea located on the south-central coast of Alaska and ringed with fjords containing tidewater glaciers, reveal the unique impact of glacial melt on CaCO3 corrosivity. Initial limited sampling was expanded in September 2011 to span large portions of the western and central sound, and included two fjords proximal to tidewater glaciers: Icy Bay and Columbia Bay. The observed conditions in these fjords affected CaCO3 corrosivity in the upper water column (< 50 m) in PWS in two ways: (1) as spring-time formation sites of mode water with near-corrosive Ω levels seen below the mixed layer over a portion of the sound, and (2) as point sources for surface plumes of glacial melt with corrosive Ω levels (Ω for aragonite and calcite down to 0.60 and 1.02, respectively) and carbon dioxide partial pressures (pCO2) well below atmospheric levels. CaCO3 corrosivity in glacial melt plumes is poorly reflected by pCO2 or pHT, indicating that either one of these carbonate parameters alone would fail to track Ω in PWS. The unique Ω and pCO2 conditions in the glacial melt plumes enhances atmospheric CO2 uptake, which, if not offset by mixing or primary productivity, would rapidly exacerbate CaCO3 corrosivity in a positive feedback. The cumulative effects of glacial melt and air–sea gas exchange are likely responsible for the seasonal reduction of Ω in PWS, making PWS highly sensitive to increasing atmospheric CO2 and amplified CaCO3 corrosivity.

scholarly journals Marine geochemical data assimilation in an efficient Earth System Model of global biogeochemical cycling

2007 ◽  
Vol 4 (1) ◽  
pp. 87-104 ◽  
Author(s):  
A. Ridgwell ◽  
J. C. Hargreaves ◽  
N. R. Edwards ◽  
J. D. Annan ◽  
T. M. Lenton ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Biogeochemical Cycling ◽  
Earth System Model ◽  
Atmospheric Co2 ◽  
System Model ◽  
Geochemical Data ◽  
Model Parameters ◽  
Earth System ◽  
Export Production ◽  
Ocean Carbon

Abstract. We have extended the 3-D ocean based "Grid ENabled Integrated Earth system model" (GENIE-1) to help understand the role of ocean biogeochemistry and marine sediments in the long-term (~100 to 100 000 year) regulation of atmospheric CO2, and the importance of feedbacks between CO2 and climate. Here we describe the ocean carbon cycle, which in its first incarnation is based around a simple single nutrient (phosphate) control on biological productivity. The addition of calcium carbonate preservation in deep-sea sediments and its role in regulating atmospheric CO2 is presented elsewhere (Ridgwell and Hargreaves, 2007). We have calibrated the model parameters controlling ocean carbon cycling in GENIE-1 by assimilating 3-D observational datasets of phosphate and alkalinity using an ensemble Kalman filter method. The calibrated (mean) model predicts a global export production of particulate organic carbon (POC) of 8.9 PgC yr−1, and reproduces the main features of dissolved oxygen distributions in the ocean. For estimating biogenic calcium carbonate (CaCO3) production, we have devised a parameterization in which the CaCO3:POC export ratio is related directly to ambient saturation state. Calibrated global CaCO3 export production (1.2 PgC yr-1) is close to recent marine carbonate budget estimates. The GENIE-1 Earth system model is capable of simulating a wide variety of dissolved and isotopic species of relevance to the study of modern global biogeochemical cycles as well as past global environmental changes recorded in paleoceanographic proxies. Importantly, even with 12 active biogeochemical tracers in the ocean and including the calculation of feedbacks between atmospheric CO2 and climate, we achieve better than 1000 years per (2.4 GHz) CPU hour on a desktop PC. The GENIE-1 model thus provides a viable alternative to box and zonally-averaged models for studying global biogeochemical cycling over all but the very longest (>1 000 000 year) time-scales.

scholarly journals Burial-nutrient feedbacks amplify the sensitivity of atmospheric carbon dioxide to changes in organic matter remineralisation

2014 ◽  
Vol 5 (2) ◽  
pp. 321-343 ◽  
Author(s):  
R. Roth ◽  
S. P. Ritz ◽  
F. Joos
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Calcium Carbonate ◽  
Atmospheric Carbon Dioxide ◽  
Atmospheric Co2 ◽  
Co2 Sensitivity ◽  
Ocean Sediment ◽  
Marine Productivity ◽  
Sediment Model

Abstract. Changes in the marine remineralisation of particulate organic matter (POM) and calcium carbonate potentially provide a positive feedback with atmospheric CO2 and climate change. The responses to changes in remineralisation length scales are systematically mapped with the Bern3D ocean–sediment model for atmospheric CO2 and tracer fields for which observations and palaeoproxies exist. Results show that the "sediment burial-nutrient feedback" amplifies the response in atmospheric CO2 by a factor of four to seven. A transient imbalance between the weathering flux and the burial of organic matter and calcium carbonate lead to sustained changes in the ocean's phosphate and alkalinity inventory and in turn in surface nutrient availability, marine productivity, and atmospheric CO2. It takes decades to centuries to reorganise tracers and fluxes within the ocean, many millennia to approach equilibrium for burial fluxes, while δ13C signatures are still changing 200 000 years after the perturbation. At 1.7 ppm m−1, atmospheric CO2 sensitivity is about fifty times larger for a unit change in the remineralisation depth of POM than of calcium carbonate. The results highlight the role of organic matter burial in atmospheric CO2 and the substantial impacts of seemingly small changes in POM remineralisation.

scholarly journals Diatoms and their influence on the biologically mediated uptake of atmospheric CO<sub>2</sub> in the Arabian Sea upwelling system

2005 ◽  
Vol 2 (1) ◽  
pp. 103-136 ◽  
Author(s):  
T. Rixen ◽  
C. Goyet ◽  
V. Ittekkot
Keyword(s):  
Calcium Carbonate ◽  
Sediment Trap ◽  
Arabian Sea ◽  
N Uptake ◽  
Atmospheric Co2 ◽  
Global Ocean ◽  
Redfield Ratio ◽  
Model Experiments ◽  
Diatom Blooms ◽  
Made In

Abstract. Model experiments have shown that diatoms can lower the atmospheric CO2-concentration when they grow at the expense of coccolithophorids, since this reduces the precipitation of calcium carbonate, which acts as an oceanic CO2 source. In the Arabian Sea we conducted long-term sediment trap experiments (water depth >1000 m) in order to study processes controlling shifts from diatom to non-diatom dominated systems. One of our major problems was to link sediment trap records to surface ocean processes. Satellite-derived observations on upper ocean parameters were helpful to reduce this problem in the past and gain a new quality by combining it with results obtained during the Joint Global Ocean Flux Study in the Arabian Sea. The new results imply that a deficiency of silicon (Si) in the euphotic zone terminates diatom blooms. Enhanced eolian iron inputs raise the availability of silicon in the surface water by decreasing the Si/N uptake ratios of diatoms. An enhanced abundance of diatoms within the plankton community seems to increase the biologically mediated uptake of atmospheric CO2 by suppressing blooms of calcium carbonate producing organisms and by elevating the carbon to nutrient uptake (Redfield) ratio. These results agree in principle with assumptions made in models but indicate also that enhanced iron concentrations hinder the development of diatom blooms. The latter could be responsible for the amplitude of derived changes in the Redfield ratio and in the ratio between organic carbon and calcium carbonate carbon production which fall below assumptions made in some model experiments.

scholarly journals Calcium carbonate corrosivity in an Alaskan inland sea

2013 ◽  
Vol 10 (9) ◽  
pp. 14887-14922
Author(s):  
W. Evans ◽  
J. T. Mathis ◽  
J. N. Cross
Keyword(s):  
Calcium Carbonate ◽  
Focal Point ◽  
Point Sources ◽  
Atmospheric Co2 ◽  
Co2 Uptake ◽  
Mode Water ◽  
Tidewater Glaciers ◽  
South Central ◽  
System Data ◽  
Shell Forming

Abstract. Ocean acidification is the hydrogen ion increase caused by the oceanic uptake of anthropogenic CO2, and is a focal point in marine biogeochemistry, in part, because this chemical reaction reduces calcium carbonate (CaCO3) saturation states (Ω) to levels that are corrosive (i.e. Ω ≤ 1) to shell-forming marine organisms. However, other processes can drive CaCO3 corrosivity; specifically, the addition of tidewater glacial melt. Carbonate system data collected in May and September from 2009 through 2012 in Prince William Sound (PWS), a semi-enclosed inland sea located on the south-central coast of Alaska that is ringed with fjords containing tidewater glaciers, reveal the unique impact of glacial melt on CaCO3 corrosivity. Initial limited sampling was expanded in September 2011 to span large portions of the western and central sound, and included two fjords proximal to tidewater glaciers: Icy Bay and Columbia Bay. The observed conditions in these fjords affected CaCO3 corrosivity in the upper water column (<50 m) in PWS in two ways: (1) as spring-time formation sites of mode water with near-corrosive Ω levels seen below the mixed layer across the sound, and (2) as point sources for surface plumes of glacial melt with corrosive Ω levels (Ω for aragonite and calcite down to 0.60 and 1.02, respectively) and carbon dioxide partial pressures (pCO2) well below atmospheric levels. CaCO3 corrosivity in glacial melt plumes is poorly reflected by pCO2 or pHT, indicating that either one of these carbonate parameters alone would fail to track Ω in PWS. The unique Ω and pCO2 conditions in the glacial melt plumes enhances atmospheric CO2 uptake, which, if not offset by mixing or primary productivity, would rapidly exacerbate CaCO3 corrosivity in a positive feedback. The cumulative effects of glacial melt and air-sea gas exchange are likely responsible for the seasonal widespread reduction of Ω in PWS; making PWS highly sensitive to increasing atmospheric CO2 and amplified CaCO3 corrosivity.

scholarly journals Glacial-interglacial productivity in the Polar Frontal Zone, southwest Pacific Ocean

2021 ◽  
Author(s):  
◽  
Melanie Anne Liston
Keyword(s):  
Calcium Carbonate ◽  
Southern Ocean ◽  
Biogenic Silica ◽  
Frontal Zone ◽  
Atmospheric Co2 ◽  
Climate Change Research ◽  
Southwest Pacific ◽  
Polar Frontal Zone ◽  
Co2 Concentrations ◽  
Atmospheric Co2 Concentrations

<p>The Southern Ocean has a central role in regulating global climate change. Research has shown evidence of changes in biological productivity are coincident with increased iron deposition and rising atmospheric CO2 concentrations. The current data suggests these processes occur homogenously throughout the Southern Ocean, where research largely focuses on changes in biogenic silica as a proxy for upwelling and enhanced opal production. The role of calcium carbonate productivity, however, is rarely discussed, or is referred to in terms of preservation changes associated with shoaling and deepening of the lysocline. This assumption ignores potentially important effects of carbonate productivity and inter-basin complexities on ocean-atmosphere CO2 exchange. Two gravity cores (TAN1302-96 and TAN1302-97) collected from the southwest Pacific Polar Frontal Zone (PFZ) provide more insight into productivity changes and inter-basin differences across glacial-interglacial timescales. Detailed geochemical analysis, together with δ18O stratigraphy and 14C chronology, were used to reconstruct glacial-interglacial changes in terrigenous input and paleoproductivity in the PFZ. Sedimentological and biological analyses provide additional information to support the geochemical observations. This study highlights two distinct productivity modes (i.e. biogenic silica and calcium carbonate) that vary over glacial-interglacial timescales and with respect to the position of the Polar Front (PF). Key findings include; 1) a systematic series of key biological changes are repeated during glacial Terminations I (TI) and II (TII), the order of which depends on the position relative to the PF; 2) calcium carbonate productivity dominates the early part of the Termination north of the PF, whereas the production of biogenic silica dominates the early Termination south of the PF; 3) following TI and TII, calcium carbonate leads productivity in the early interglacials (i.e. MIS 5e and the Holocene), followed by the production of biogenic silica during the late interglacials, concurrent with declining atmospheric CO2 concentrations.</p>

scholarly journals The fate of pelagic CaCO<sub>3</sub> production in a high CO<sub>2</sub> ocean: a model study

2007 ◽  
Vol 4 (4) ◽  
pp. 505-519 ◽  
Author(s):  
M. Gehlen ◽  
R. Gangstø ◽  
B. Schneider ◽  
L. Bopp ◽  
O. Aumont ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Inorganic Carbon ◽  
Atmospheric Co2 ◽  
Saturation State ◽  
Carbonate Production ◽  
Model Simulations ◽  
Carbon Production ◽  
Model Study ◽  
Time Period ◽  
Organic And Inorganic Carbon

Abstract. This model study addresses the change in pelagic calcium carbonate production (CaCO3, as calcite in the model) and dissolution in response to rising atmospheric CO2. The parameterization of CaCO3 production includes a dependency on the saturation state of seawater with respect to calcite. It was derived from laboratory and mesocosm studies on particulate organic and inorganic carbon production in Emiliania huxleyi as a function of pCO2. The model predicts values of CaCO3 production and dissolution in line with recent estimates. The effect of rising pCO2 on CaCO3 production and dissolution was quantified by means of model simulations forced with atmospheric CO2 increasing at a rate of 1% per year from 286 ppm to 1144 ppm over a 140 year time-period. The simulation predicts a decrease of CaCO3 production by 27%. The combined change in production and dissolution of CaCO3 yields an excess uptake of CO2 from the atmosphere by the ocean of 5.9 GtC over the period of 140 years.

scholarly journals The fate of pelagic CaCO<sub>3</sub> production in a high CO<sub>2</sub> ocean: A model study

2007 ◽  
Vol 4 (1) ◽  
pp. 533-560 ◽  
Author(s):  
M. Gehlen ◽  
R. Gangstø ◽  
B. Schneider ◽  
L. Bopp ◽  
O. Aumont ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Inorganic Carbon ◽  
Emiliania Huxleyi ◽  
Atmospheric Co2 ◽  
Saturation State ◽  
Carbonate Production ◽  
Model Simulations ◽  
Carbon Production ◽  
Model Study ◽  
Organic And Inorganic Carbon

Abstract. This model study addresses the change in pelagic calcium carbonate production (CaCO3, as calcite in the model) and dissolution in response to rising atmospheric CO2. The parameterization of CaCO3 production includes a dependency on the saturation state of seawater with respect to calcite. It was derived from laboratory and mesocosm studies on particulate organic and inorganic carbon production in Emiliania huxleyi as a function of pCO2. The model predicts values of CaCO3 production and dissolution in line with recent estimates. The effect of rising pCO2 on CaCO3 production and dissolution was quantified by means of model simulations forced with atmospheric CO2 increasing at a rate of 1% per year from 286 ppm to 1144 ppm. The simulation predicts a decrease of CaCO3 production by 27%. The combined change in production and dissolution of CaCO3 yields an excess uptake of CO2 from the atmosphere by the ocean of 5.9 GtC.

scholarly journals Ease into Climate Change Instruction through Ocean Acidification

2021 ◽  
Vol 83 (4) ◽  
pp. 247-253
Author(s):  
David C. Owens ◽  
Susanne Rafolt ◽  
Erin M. Arneson
Keyword(s):  
Climate Change ◽  
Calcium Carbonate ◽  
Ocean Acidification ◽  
Food Webs ◽  
Fossil Fuels ◽  
Food Resources ◽  
Atmospheric Co2 ◽  
Anthropogenic Sources ◽  
Oceanic Food Webs ◽  
Sources Of Co2

Although climate change garners the bulk of headlines, ocean acidification is an equally important issue that also results from our increasing consumption of fossil fuels. As atmospheric CO2 dissolves into the ocean, the ocean’s pH decreases, making it increasingly difficult for organisms that build calcium carbonate skeletons to grow and thrive. Given that these marine calcifiers – such as corals, snails, shellfish, crustaceans, and plankton – often form the base of oceanic food webs and are habitat and food resources for larger oceanic plants and animals (including humans), ocean acidification poses a serious threat. In this article, we present a series of investigations that provide evidence that increases in anthropogenic sources of CO2 contribute to the acidification of the ocean, and that an increasingly acidic ocean can negatively impact marine calcifiers.

scholarly journals Glacial-interglacial productivity in the Polar Frontal Zone, southwest Pacific Ocean

2021 ◽  
Author(s):  
◽  
Melanie Anne Liston
Keyword(s):  
Calcium Carbonate ◽  
Southern Ocean ◽  
Biogenic Silica ◽  
Frontal Zone ◽  
Atmospheric Co2 ◽  
Climate Change Research ◽  
Southwest Pacific ◽  
Polar Frontal Zone ◽  
Co2 Concentrations ◽  
Atmospheric Co2 Concentrations

<p>The Southern Ocean has a central role in regulating global climate change. Research has shown evidence of changes in biological productivity are coincident with increased iron deposition and rising atmospheric CO2 concentrations. The current data suggests these processes occur homogenously throughout the Southern Ocean, where research largely focuses on changes in biogenic silica as a proxy for upwelling and enhanced opal production. The role of calcium carbonate productivity, however, is rarely discussed, or is referred to in terms of preservation changes associated with shoaling and deepening of the lysocline. This assumption ignores potentially important effects of carbonate productivity and inter-basin complexities on ocean-atmosphere CO2 exchange. Two gravity cores (TAN1302-96 and TAN1302-97) collected from the southwest Pacific Polar Frontal Zone (PFZ) provide more insight into productivity changes and inter-basin differences across glacial-interglacial timescales. Detailed geochemical analysis, together with δ18O stratigraphy and 14C chronology, were used to reconstruct glacial-interglacial changes in terrigenous input and paleoproductivity in the PFZ. Sedimentological and biological analyses provide additional information to support the geochemical observations. This study highlights two distinct productivity modes (i.e. biogenic silica and calcium carbonate) that vary over glacial-interglacial timescales and with respect to the position of the Polar Front (PF). Key findings include; 1) a systematic series of key biological changes are repeated during glacial Terminations I (TI) and II (TII), the order of which depends on the position relative to the PF; 2) calcium carbonate productivity dominates the early part of the Termination north of the PF, whereas the production of biogenic silica dominates the early Termination south of the PF; 3) following TI and TII, calcium carbonate leads productivity in the early interglacials (i.e. MIS 5e and the Holocene), followed by the production of biogenic silica during the late interglacials, concurrent with declining atmospheric CO2 concentrations.</p>

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