Marine sulfur cycle

Figure 13-5 is the box model of the remote marine sulfur cycle that results from these assumptions. Many different data sets are displayed (and compared) as follows. Each box shows a measured concentration and an estimated residence time for a particular species. Fluxes adjoining a box are calculated from these two pieces of information using the simple formula, S-M/x. The flux of DMS out of the ocean surface and of nss-SOl back to the ocean surface are also quantities estimated from measurements. These are converted from surface to volume fluxes (i.e., from /ig S/(m h) to ng S/(m h)) by assuming the effective scale height of the atmosphere is 2.5 km (which corresponds to a reasonable thickness of the marine planetary boundary layer, within which most precipitation and sulfur cycling should take place). Finally, other data are used to estimate the factors for partitioning oxidized DMS between the MSA and SO2 boxes, for SO2 between dry deposition and oxidation to sulfate, and for nss-SO4 between wet and dry deposition. 

O Dowd, C. D., M. H. Smith, I. E. Consterdine, and J. A. Lowe, Marine Aerosol Sea-Salt and the Marine Sulfur Cycle-A Short Review, Atmos. Environ., 31, 73-80 (1997). 

Figure 13-5 is the box model of the remote marine sulfur cycle that results from these assumptions. Many different data sets are displayed (and compared) as follows. Each box shows a measured concentration and an estimated residence time for a particular species. Fluxes adjoining a box are calculated from these two pieces of information using the simple formula, S = Mix. The flux of DMS out of the ocean surface and of nss-SOj back to the ocean surface are also quantities estimated from measurements. These are converted from surface to... 

Fig. 13-5 The sulfur cycle in the remote marine boundary layer. Within the 2500 m boundary layer, burden units are ng S/m and flux units are ng S/m h. Fluxes within the atmospheric layer are calculated from the burden and the residence time. Dots indicate that calculations based on independent measurements are being compared. The measured wet deposition of nss-SO " (not shown) is 13 7 //g S/m /h Inputs and outputs roughly balance, suggesting that a consistent model of the remote marine sulfur cycle within the planetary boundary layer can be constructed based on biogenic DMS inputs alone. Data (1) Andreae (1986) (2) Galloway (1985) (3) Saltzman et al. (1983) (4) sulfate aerosol lifetime calculated earlier in this chapter based on marine rainwater pH the same lifetime is applied to MSA aerosol. Modified from Crutzen et al. (1983) with the permission of Kluwer Academic Publishers.

This problem is a first-order attempt to quantify the possible anthropogenic perturbation of the northern hemisphere (NH) marine sulfur cycle. First, assume that present-day anthropogenic sulfur emissions result in 20 Tg S/year being transported from North America to the atmosphere over the NH Atlantic and 10 Tg S/year being transported from Asia to the atmosphere over the NH Pacific. Assume a uniform concentration in the N-S direction, average westerly wind speeds... 

The authors of the first edition have revised and substantially updated and enlarged their chapters. We had to give up the partial chapter on sedimentary magnetism of the first edition. In chapter 6 the authors now concentrate on benthic cycles, and the new co-author Heide N. Schulz especially reports on phosphoms cycles and the microbial parts. Chapter 8 was extended to the complete marine sulfur cycling in connection with anaerobic methane oxidation. Gerhard Bohrmann and Marta E. Torres contribute their completely new chapter 14 on methane hydrates in marine sediments, representing a well-rounded presentation of this exciting discipline, which will be of major interest in the future. 

Jorgensen, B. B. (1990). A thiosulfate shunt in the sulfur cycle of marine sediments. Science 249, 152-154. 

Interest in the possible persistence of aliphatic sulfides has arisen since they are produced in marine anaerobic sediments, and dimethylsulfide may be implicated in climate alteration (Charlson et al. 1987). Dimethylsnlfoniopropionate is produced by marine algae as an osmolyte, and has aronsed attention for several reasons. It can be the source of climatically active dimethylsulfide (Yoch 2002), so the role of specific bacteria has been considered in limiting its flux from the ocean and deflecting the prodncts of its transformation into the microbial sulfur cycle (Howard et al. 2006). 

Thamdrup B, Fossing H, Jeorgensen BB (1994) Manganese, iron and sulfur cycling in a coastal marine sediment, Aarhus Bay, Denmark. Geochim Cosmochim Acta 58 5115-5129... 

Godfrey JD (1962) The deuterium content of hydrous minerals from the East Central Sierra Nevada and Yosemite National Park. Geochim Cosmochim Acta 26 1215-1245 Goericke R, Fry B (1994) Variations of marine plankton 6 C with latitude, temperature and dissolved CO2 in the world ocean. Global Geochem Cycles 8 85-90 Goldhaber MB, Kaplan IR (1974) The sedimentary sulfur cycle. In Goldberg EB (ed) The sea, vol. 4. WUey, New York... 

Gharacterization of inorganic sulfur speci-ation in marine and freshwater porewaters is critical to our understanding of metal and sulfur cycling in sediments. Since coprecipitation and/or adsorption on FeS(g) and formation of discrete authigenic sulfide minerals can effectively remove trace metals, many metal cycling studies are... 

Jorgensen, B. B. Fencher, T. (1974). The sulfur cycle of a marine sediment model system. Marine Biology, 24, 189-201. 

Zhuang, G., Yi, Z., Duce, RA. and Brown, PR. (1992) Link between iron and sulfur cycles suggested by detection of Fe11 in remote marine aerosols. Nature, 355, 537-539. 

Cano RJ, Borucki MK (1995) Revival and identification of bacterial spores in 25- to 40-million-year-old Dominican amber. Science 268 1060-1064 Carlson RW, Anderson MS, Johnson RE, Smythe WD, Hendrix AR, Barth CA, Soderblom LA, Hansen GB, McCord TB, Dalton JB, Clark RN, Shirley JH, Ocampo AC, Matson DL (1999a) Hydrogen peroxide on the surface of Europa. Science 283 2062-2064 Carlson RW, Johnson RE, Anderson MS (1999b) Sulfuric acid on Europa and the radiolytic sulfuric cycle. Science 26 97-99 Carney RS (1994) Consideration of the oasis analogy for chemosynthetic communities at Gulf of Mexico hydrocarbon vents. Geo-Marine Lett 14 149-159... 

Current research on the atmospheric cycling of sulfur compounds involves the experimental determination of reaction rates and pathways (see Plane review, this volume) and the field measurement of ambient concentrations of oceanic emissions and their oxidation products. Photochemical models of tropospheric chemistry can predict the lifetime of DMS and H2S in marine air however there is considerable uncertainty in both the concentrations and perhaps in the identity of the oxidants involved. The ability of such models to simulate observed variations in ambient concentrations of sulfur gases is thus a valuable test of our assumptions regarding the rates and mechanisms of sulfur cycling through the marine atmosphere. 

Once DMS is emitted into the atmosphere it will eventually be oxidized by OH or NO3 radicals to sulfur dioxide (SO2), methanesulfonic acid (MSA), and, via SO oxidation, to non-sea-salt sulfate (nss-S042 ) as major reaction products (e.g. 10.111. The Southern Ocean represents a relatively unpolluted marine environment. It offers a unique possibility to study the natural sulfur cycle in an atmosphere far remote from man-inhabited continents. 

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