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  • 1
    Publication Date: 2022-11-06
    Description: Author Posting. © American Geophysical Union, 2022. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 36(5), (2022): e2022GB007388, https://doi.org/10.1029/2022gb007388.
    Description: The cycling of biologically produced calcium carbonate (CaCO3) in the ocean is a fundamental component of the global carbon cycle. Here, we present experimental determinations of in situ coccolith and foraminiferal calcite dissolution rates. We combine these rates with solid phase fluxes, dissolved tracers, and historical data to constrain the alkalinity cycle in the shallow North Pacific Ocean. The in situ dissolution rates of coccolithophores demonstrate a nonlinear dependence on saturation state. Dissolution rates of all three major calcifying groups (coccoliths, foraminifera, and aragonitic pteropods) are too slow to explain the patterns of both CaCO3 sinking flux and alkalinity regeneration in the North Pacific. Using a combination of dissolved and solid-phase tracers, we document a significant dissolution signal in seawater supersaturated for calcite. Driving CaCO3 dissolution with a combination of ambient saturation state and oxygen consumption simultaneously explains solid-phase CaCO3 flux profiles and patterns of alkalinity regeneration across the entire N. Pacific basin. We do not need to invoke the presence of carbonate phases with higher solubilities. Instead, biomineralization and metabolic processes intimately associate the acid (CO2) and the base (CaCO3) in the same particles, driving the coupled shallow remineralization of organic carbon and CaCO3. The linkage of these processes likely occurs through a combination of dissolution due to zooplankton grazing and microbial aerobic respiration within degrading particle aggregates. The coupling of these cycles acts as a major filter on the export of both organic and inorganic carbon to the deep ocean.
    Description: This work was funded by NSF OCE-1220301 to W.B., NSF OCE-1220600 to J.F.A., and startup funding for A.V.S.
    Description: 2022-11-06
    Keywords: Calcium carbonate ; Dissolution ; Carbon cycle
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 2
    Publication Date: 2022-05-26
    Description: Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 39 (2012): L07606, doi:10.1029/2012GL051574.
    Description: The carbon system of the western Arctic Ocean is undergoing a rapid transition as sea ice extent and thickness decline. These processes are dynamically forcing the region, with unknown consequences for CO2 fluxes and carbonate mineral saturation states, particularly in the coastal regions where sensitive ecosystems are already under threat from multiple stressors. In October 2011, persistent wind-driven upwelling occurred in open water along the continental shelf of the Beaufort Sea in the western Arctic Ocean. During this time, cold (〈−1.2°C), salty (〉32.4) halocline water—supersaturated with respect to atmospheric CO2 (pCO2 〉 550 μatm) and undersaturated in aragonite (Ωaragonite 〈 1.0) was transported onto the Beaufort shelf. A single 10-day event led to the outgassing of 0.18–0.54 Tg-C and caused aragonite undersaturations throughout the water column over the shelf. If we assume a conservative estimate of four such upwelling events each year, then the annual flux to the atmosphere would be 0.72–2.16 Tg-C, which is approximately the total annual sink of CO2 in the Beaufort Sea from primary production. Although a natural process, these upwelling events have likely been exacerbated in recent years by declining sea ice cover and changing atmospheric conditions in the region, and could have significant impacts on regional carbon budgets. As sea ice retreat continues and storms increase in frequency and intensity, further outgassing events and the expansion of waters that are undersaturated in carbonate minerals over the shelf are probable.
    Description: Funding for this work was provided by the National Science Foundation (ARC1041102 – JTM, OPP0856244-RSP, and ARC1040694- LWJ), the National Oceanic and Atmospheric Administration (CIFAR11021- RHB) and the West Coast & Polar Regions Undersea Research Center (POFP00983 – CLM and JM).
    Description: 2012-10-11
    Keywords: Arctic Ocean ; CO2 fluxes ; Ocean acidification ; Upwelling
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: text/plain
    Format: image/tiff
    Format: application/msword
    Format: application/pdf
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 11 (1982), S. 127-136 
    ISSN: 1572-8927
    Keywords: Lead ; lead bromide ; lead chloride ; mixed ligand ; complexation ; spectroscopic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Experimentally and theoretically derived formation constants of mixed lead halide complexes are compared at 25.0°C and one molar ionic strength. The formation constant of PbBrCl, β11=79±10, is somewhat larger than the theoretical results, β11=55, predicted using the formation constants of PbBr2 and PbCl2. The molar absorptivity of PbBrCl was observed to be intermediate in character between the molar absorptivities of PbBr2 and PbCl2. Determinations of the formation constants of PbBr2Cl− and PbBrCl2 − are in reasonable agreement with the predictions based on the formation constants of PbBr3 − and PbCl3 −. Mixed ligand species dominated the complexation scheme of Pb(II) in our test media.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 16 (1987), S. 555-566 
    ISSN: 1572-8927
    Keywords: Europium ; carbonate complexation ; carbonic acid dissociation ; tributy phosphate extraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The temperature dependencies of europium carbonate stability constants were examined at 15, 25, and 35°C in 0.68 molal Na+(ClO 4 − , HCO 3 − ) using a tributyl phosphate solvent extration technique. Our distribution data can be explained by the equilibria $$\begin{gathered} Eu^{3 + } + H_2 O + CO_2 (g)_ \leftarrow ^ \to EuCO_3^ + + 2H^ + \hfill \\ - log\beta _{12} = 9.607 + 496(t + 273.16)^{ - 1} \hfill \\ Eu^{3 + } + 2H_2 O + 2CO_2 (g)_ \leftarrow ^ \to Eu(CO_3 )_2^ - + 4H^ + \hfill \\ - log\beta _{24} = 21.951 + 670(t + 273.16)^{ - 1} \hfill \\ Eu^{3 + } + H_2 O + CO_2 (g)_ \leftarrow ^ \to EuHCO_3^{2 + } + H^ + \hfill \\ - log\beta _{11} = 1.688 + 1397(t + 273.16)^{ - 1} \hfill \\ \end{gathered}$$
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 22 (1993), S. 751-766 
    ISSN: 1572-8927
    Keywords: Rare earth elements ; fluoride complexation ; stability constant ; solvent exchange ; tributyl phosphate ; sodium perchlorate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Rare earth fluoride stability constants for Ce, Eu, Gd, Tb and Yb at 25°C have been determined by examining the influence of fluoride ions on the distribution of rare earths between tributyl phosphate (TBP) and 0.68M NaClO4. Our results indicate that rare earth mono and difluoro complexation constants show a steady increase as a function of atomic number from La to Tb but remain relatively constant after Dy. This behavior is similar to that which has been observed for dicarboxylic acids. Stepwise stability constant ratios, K2/K1, obtained in our work (where K1=[MF2+][M3+]−1[F−]−1 and K2=[MF 2 + ]−1[MF2+]−1[F−]−1) indicated that, for all rare earths, K2/K1=0.09±0.03.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 10 (1981), S. 51-67 
    ISSN: 1572-8927
    Keywords: Hydrolysis ; ferric chloride ; ferric hydroxide ; UV spectroscopy ; complexes ; ion pairs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The equilibria among the species Fe3+, FeCl2+, FeCl2 +, FeOH2+ and Fe(OH)2 + have been examined by ultraviolet absorption spectroscopy. Our results indicate that previous workers have generally overestimated the stability constant of FeCl2+ and that the association of Fe3+ and Cl− is predominantly inner sphere. The formation constant of FeOH2+ obtained in 0.68 m NaCl is in good agreement with our earlier results obtained in 0.68 m NaClO4. Our results indicate that formation of FeOHCl+ is much less significant than has been previously reported. Molar absorptivities for the species Fe3+, FeCl2+, FeCl2 + and FeOH2+ are reported for wavelengths between 220 and 400 nanometers.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 10 (1981), S. 243-251 
    ISSN: 1572-8927
    Keywords: Lead chloride ; molar absorptivity ; complexation ; medium dependence ; ultraviolet ; spectroscopic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The molar absorptivities of Pb2+, PbCl+, PbCl2, and PbCl 3 − were obtained between 210 and 300 nm. Molar absorptivity data were used to determine lead speciation directly from Pb(II) absorbance characteristics in a variety of media including natural seawater. The absorbance characteristics of lead in a particular chloride medium reveal the lead chloride formation constants appropriate to that medium. Our analyses indicate that lead chloride formation constants are significantly smaller in MgCl2 media than in HCl at constant ionic strength.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 12 (1983), S. 581-596 
    ISSN: 1572-8927
    Keywords: Copper ; molar absorptivity ; complexation ; spectroscopy ; copper and magnesium chloride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Upper and lower bound estimates of the CuCl+ stability constants produced by various investigations have been quantitatively examined. Our analyses, including our own ultraviolet spectroscopic investigations, indicate that the CuCl+ stability constant in 1 molar HClO4 is β1=0.70±0.23. The CuCl+ molar absorptivity at a wavelength of 250 nm was determined as 1860 cm2-mol−1. Our analyses suggest the bound β 1 ′≤0.37 for the formation constant of MgCl+ at one molar ionic strength.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 7 (1978), S. 373-383 
    ISSN: 1572-8927
    Keywords: Ferric ; hydrolysis ; ionic strength ; temperature ; enthalpy ; ferric hydroxide ; ultraviolet ; spectroscopic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Ultraviolet absorbance spectra of ferric ions in 0.68m NaClO4 were studied as a function of pH at 4.0, 14.9, and 25.0°C. The results provided an evaluation of the stability constant for the formation of FeOH2+ which is *β1=[FeOH +][H +]/[Fe 3+]. The enthalpy change for the reaction Fe3++H2O⇌ FeOH2++H+ was calculated as 10.0±0.3 kcal-mole−1. Increasing temperature was also found to promote the reaction Fe3++2H2O⇌ Fe(OH) 2 + +2H+. Our results were combined with the results of other to produce an expression describing the first hydrolysis equilibrium at ionic strengths between 0 and 3m and temperatures between 4.0 and 45.0°C at 1 atm total pressure. At 25°C and 0.68m the ionic strength *β1=1.90×10-3
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 27 (1998), S. 803-815 
    ISSN: 1572-8927
    Keywords: Rare earth ; complexation ; carbonate ; ICP–MS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Carbonate stability constants for yttrium and all rare earth elements have been determined at 25°C and 0.70 molal ionic strength by solvent exchange and inductively coupled plasma–mass spectrometry (ICP–MS). Measured stability constants for the formation of $${\text{MCO}}_3^ +$$ and $${\text{M}}\left( {{\text{CO}}_{\text{3}} } \right)_2^--$$ from M3+ are in good agreement with previous direct measurements, which involved the use of radio-chemical techniques and trivalent ions of Y, Ce, Eu, Gd, Tb, and Yb. Direct ICP–MS measurements of $${\text{MCO}}_3^ +$$ and $${\text{M}}\left( {{\text{CO}}_{\text{3}} } \right)_2^--$$ formation constants are also in general agreement with modeled stability constants for the metals La, Pr, Nd, Sm, Dy, Ho, Er, Tm, and Lu, based on linear-free energy relationship (LFER). The experimental procedures developed in this work can be used for assessing the complexation behavior of other geochemically important ligands such as phosphate, sulfate, and fluoride.
    Type of Medium: Electronic Resource
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