Upper ocean chemistry

As we come to fuUy appreciate the implications of increasing atmospheric carbon dioxide concentrations on upper ocean chemistry and physical stmcture, it is important that we evaluate these impacts on m or biogeochemical processes. N2 fixation is an obvious ecological function that requires such evaluation. Preliminary assessment of the effect of temperature shifts on the distribution of Trichodesmium populations in the upper ocean have been made (Breitbarth et al., 2006). The physiological effects of increasing CO2 have only recendy been realized (Levitan etal., 2006 Barcelos e Ramos et al., 2007 Hutchins et al., 2007). These studies necessarily need to be extended to other relevant diazotrophs as well as to the effects of pH. 

Alt, J.C. and Honnorez, J. (1984) Alteration of the upper oceanic crust, DSDP site 417 mineralogy and chemistry. Contr. Mineral. Petrol, 87, 149-169. 

Andrew Dickson (Chair) is an Associate Professor-in-Residence at the Scripps Institution of Oceanography. His research focuses on the analytical chemistry of carbon dioxide in sea water, biogeochemical cycles in the upper ocean, marine inorganic chemistry, and the thermodynamics of electrolyte solutions at high temperatures and pressures. His expertise lies in the quality control of oceanic carbon dioxide measurements and in the development of underway instrumentation for the study of upper ocean biogeochemistry. Dr. Dickson served on the NRC Committee on Oceanic Carbon. He is presently a member of the IOC C02 Advisory Panel and of the PICES Working Group 13 on C02 in the North Pacific. 

The concentration of 210Po in seawater is generally close to what would be expected from radiochemical equilibrium with its grandparent, 210Pb. Below 400 m, Po activities are very similar to those of Pb. At shallower depths, the concentrations of Po and Pb are somewhat decoupled. Po is more readily adsorbed by particles than is Pb in the surface ocean (Bernat and Church, 1989) and, due to the short residence times of particles in the upper ocean, the relative concentrations of Po and Pb are controlled, in part, by particle fluxes and differences in polonium and lead solution and surface chemistries. The chemistry of... 

Bruland, K.W., and Coale, K.H. (1986) Surface water 234Th/238U disequilibria spatial and temporal variations of scavenging rates within the Pacific Ocean. In Dynamic Processes in the Chemistry of the Upper Ocean (Burton, J.D., ed), pp. 159-172, Plenum Publications, New York. 

Alt J. C., Honnorez J., Laverne C., and Emmermann R. (1986) Hydrothermal Alteration of a 1 km section through the upper oceanic crust DSDP hole 504B the mineralogy, chemistry and evolution of seawater-basalt interactions. J. Geophys. Res. 91, 10309-10335. 

LaVerne C., Belarouchi A., and Honnorez J. (1996) Alteration mineralogy and chemistry of the upper oceanic crust from hole 896A, Costa Rica rift. In Proceedings of Ocean Drilling Program Scientific Reports (eds. J. C. Alt, H. Kinoshita, L. B. Stokking, and P. J. Michael), vol. 148, pp. 151-170. 

Figure 1. The evolution of chemical oceanography, 1884-1984, Oceanic fronts are characterized by areas of enhanced biological activity—the major process by which the chemistry of the upper ocean varies on a short time...

The studies in this book (by Zuehlke and Kester, Herman, Schink, Traganza, and others) indicate that biological activity is the major process changing the chemistry of the upper ocean on a short time scale. Unravel-... 

Ce undergoes an active redox chemistry in the upper oceans. Experiments have shown that the oxidation of dissolved Ce(III) to particulate Ce(IV) oxides is microbially mediated and related to the redox chemistry of Mn (Moffett 1990, 1994a,b). High surface water concentrations of dissolved Ce (fig. 14d) appear to reflect oxidative removal at depth and reductive solubilization near the surface. Profiles of surface-bound Ce on suspended particles confirm that there is in situ oxidation of dissolved Ce(III) to particulate Ce(IV) in the upper oceans (Sholkovitz et al. 1994). 

Bishop J. K. B., Edmond J. M., Ketten D. R., Bacon M. P., and Silker W. B. (1977) Chemistry, biology, and vertical flux of particulate matter from upper 400 m of Equatorial Atlantic Ocean. Deep-Sea Res. 24(6), 511-548. 

Figure 1). The solute exchanges resulting from reactions in surface sediments can be important for the chemistry of oceanic deep water, and to the overall cycles of several elements in the oceans. In addition, the alteration of particles by these reactions must be taken into account when down-core records of the accumulation of sedimentary components are interpreted in terms of past oceanic and atmospheric chemistry. Understanding early diagenetic reactions in the upper few centimeters of the marine sediment column is important both to the study of geochemical cycles in the contemporary ocean and to the reconstruction of past oceanic conditions. 

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