Thermodynamics Of Seawater Research Articles

Response to Comment by Zeebe and Tyrrell on “The Effects of Secular Calcium and Magnesium Concentration Changes on the Thermodynamics of Seawater Acid/Base Chemistry: Implications for the Eocene and Cretaceous Ocean Carbon Chemistry and Buffering”

Key Points Suspect parameters were changed to new reference The main results of original study hold true We demonstrate skill of MyAMI model, which is superior to existing correction factors

Comment on “The Effects of Secular Calcium and Magnesium Concentration Changes on the Thermodynamics of Seawater Acid/Base Chemistry: Implications for Eocene and Cretaceous Ocean Carbon Chemistry and Buffering” by Hain et al. (2015)

Hain et al. (2015, https://doi.org/10.1002/2014GB004986, hereafter H15) calculated effects of changing [Ca2+] and [Mg2+] on the equilibrium constants of the CO2‐CaCO3 system in seawater based on a Pitzer ionic interaction model. We show here that critical results presented in H15 are fundamentally wrong. We therefore do not recommend using H15's stoichiometric equilibrium constants to correct for past changes in major‐ion seawater composition.

The effects of secular calcium and magnesium concentration changes on the thermodynamics of seawater acid/base chemistry: Implications for Eocene and Cretaceous ocean carbon chemistry and buffering

AbstractReconstructed changes in seawater calcium and magnesium concentration ([Ca2+], [Mg2+]) predictably affect the ocean's acid/base and carbon chemistry. Yet inaccurate formulations of chemical equilibrium “constants” are currently in use to account for these changes. Here we develop an efficient implementation of the MIAMI Ionic Interaction Model to predict all chemical equilibrium constants required for carbon chemistry calculations under variable [Ca2+] and [Mg2+]. We investigate the impact of [Ca2+] and [Mg2+] on the relationships among the ocean's pH, CO2, dissolved inorganic carbon (DIC), saturation state of CaCO3 (Ω), and buffer capacity. Increasing [Ca2+] and/or [Mg2+] enhances “ion pairing,” which increases seawater buffering by increasing the concentration ratio of total to “free” (uncomplexed) carbonate ion. An increase in [Ca2+], however, also causes a decline in carbonate ion to maintain a given Ω, thereby overwhelming the ion pairing effect and decreasing seawater buffering. Given the reconstructions of Eocene [Ca2+] and [Mg2+] ([Ca2+]~20 mM; [Mg2+]~30 mM), Eocene seawater would have required essentially the same DIC as today to simultaneously explain a similar‐to‐modern Ω and the estimated Eocene atmospheric CO2 of ~1000 ppm. During the Cretaceous, at ~4 times modern [Ca2+], ocean buffering would have been at a minimum. Overall, during times of high seawater [Ca2+], CaCO3 saturation, pH, and atmospheric CO2 were more susceptible to perturbations of the global carbon cycle. For example, given both Eocene and Cretaceous seawater [Ca2+] and [Mg2+], a doubling of atmospheric CO2 would require less carbon addition to the ocean/atmosphere system than under modern seawater composition. Moreover, increasing seawater buffering since the Cretaceous may have been a driver of evolution by raising energetic demands of biologically controlled calcification and CO2 concentration mechanisms that aid photosynthesis.

Thermodynamics of water, vapor, ice, and seawater

The SCOR/IAPSO Working Group 127 was founded in 2005 and charged with the development of a new, comprehensive, highly accurate, and consistent standard formulation of seawater thermodynamics for oceanography. This task was approached in cooperation with the International Association for the Properties of Water and Steam (IAPWS) for a joint standard with industrial applications. In addition to the available standard for fluid water, IAPWS-95, new formulations for ice, IAPWS-06, and the thermodynamics of seawater, IAPWS-08, have been developed, supplemented by a redefinition of salinity, the Reference-Composition Salinity Scale 2008. In this paper the starting situation is described, the requirements to be met during the development process are studied, and the properties of the final formulations are briefly characterized.

The Bernoulli function and flux of energy in the ocean

This short note explains how the Bernoulli function, the total energy of a fluid, can be calculated from recent work on the thermodynamics of seawater. The Bernoulli function for an incompressible fluid has been used in the past to infer the absolute circulation of the ocean from hydrographic data alone. This is now both undesirable and unnecessary. Constructing the Bernoulli function for a hydrographic section also provides a rigorous procedure for calculating the total energy flux across the section, a quantity dominated by the “heat flux”.

The thermodynamics of sea water, Part I

Variations, as a function of temperature, are reported in the magnitude of values for the partial molal volume, partial molal expansibility, flowing volume and surface pressure for dilute solutions of a series of poly(vinyl alcohol-co-vinyl acetate) copolymers of various vinyl acetate contents and acetate sequence length. The temperature range investigated, from 5° to 30°, showed that, for all the examples examined, a general behaviour pattern was observed, indicating the predominance of hydrophilic interactions at temperatures below approximately 10°, with hydrophobic interactions predominating between 10° and 20°. The variations can be related to the detailed microstructure of the polymer backbone.

The thermodynamics of seawater at one atmosphere; erratum

The thermodynamics of seawater at one atmosphere; erratum

Thermodynamics of Seawater as a Multicomponent Electrolyte Solution (in Two Parts). J. V. Leyendekkers

Previous articleNext article No AccessNew Biological BooksThermodynamics of Seawater as a Multicomponent Electrolyte Solution (in Two Parts). J. V. Leyendekkers Iver W. DuedallIver W. Duedall Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Quarterly Review of Biology Volume 52, Number 4Dec., 1977 Published in association with Stony Brook University Article DOIhttps://doi.org/10.1086/410249 PDF download Crossref reports no articles citing this article.

The thermodynamics of seawater at one atmosphere : MILLERO F. J. and W. H. LEUNG, 1976. Am. J. Sci., 276 (9): 1035–1077

The thermodynamics of seawater at one atmosphere : MILLERO F. J. and W. H. LEUNG, 1976. Am. J. Sci., 276 (9): 1035–1077

The thermodynamics of seawater at one atmosphere

The solution thermodynamic properties of seawater at 1 atm have been examined over the range of 0/sup 0/ to 40/sup 0/C and 0 to 40% salinity. By combining the osmotic coefficients (phi = -(55.51/2m) ln a/sub 1/, where m is the molality and a/sub 1/ is the activity of water) determined from the freezing point measurements of Doherty and Kester (1974), with the heat capacity data of Millero, Perron, and Desnoyers (1973), and the enthalpy data of Millero, Hansen, and Hoff (1973), the osmotic coefficients were determined over the range of 0/sup 0/ to 40/sup 0/C at 1 atm using the extended Debye-Heuckel equation. The results at 25/sup 0/C were found to be in excellent agreement with the results of Robinson (1954). From the osmotic coefficient data, the vapor pressure and osmotic pressure have been determined. The osmotic coefficient data at 0/sup 0/C has been used to calculate the mean activity coefficient and activity of ''sea salt.'' By using the thermodynamic equation delta lna/sub 2//delta T + - anti L/sub 2//RT, activities have been determined at other temperatures (0/sup 0/ to 40/sup 0/C). The relative free energies of seawater, G - G/sup 0/ + 55.51 RT ln a/sub 1/ =more » m RT ln a/sub 2/, have been calculated from the osmotic and activity data.The relative entropy of seawater (S - S/sup 0/) was determined from the relative free energies by using the thermodynamic relationship, S - S/sup 0/ + ((G - G/sup 0/) - (H - H/sup 0/))/T, where H - H/sup 0/ is the relative enthalpy. All the specific thermochemical properties (P) of seawater have been fitted to equations.« less

THE THERMODYNAMICS OF SEA WATER

THE THERMODYNAMICS OF SEA WATER

THE THERMODYNAMICS OF SEA WATER

THE THERMODYNAMICS OF SEA WATER