Equatorial Atlantic

Froelich, P. M., Klinkhammer, G. P., Bender, M. L. et al. (1979). Early oxidation of organic matter in pelagic sediments of the eastern equatorial Atlantic suboxic diagenesis, Geochem. Cosmochim. Acta 43, 1075-1090. 

Charette MA, Moran SB (1999) Rates of particle scavenging and particulate oiganic carbon export estimated using as a tracer in the subtropical and equatorial Atlantic Ocean. Deep-Sea Res II 46 885-906... 

Sarin MM, Kim G, Church TM (1999) °Po and °Pb in the South-equatorial Atlantic distribution and disequilibrium in the upper 500 m. Deep-Sea Res II 46 907-917 Schmidt S, Andersen V, Belviso S, Marty JC (2002) Strong seasonahty in particle dynamics of northwestern Mediterranean surface waters as revealed by " Th/ U. Deep-Sea Res 149 1507-1518 Shimmield GB, Ritchie GD, Fileman TW (1995) The impact of marginal ice zone processes on the distribution of °Pb, °Po and " Th and implications for new production in the Bellinghausen Sea, Antarctica. Deep-Sea Res II 42 1313-1335... 

Other applications of °Thxs profiling to assess accumulation rates of sedimentary components include carbonate accumulation in the Western Equatorial Atlantic (Rtihlemann et al. 1996) biogenic and terriginous particle accumulation on the Australian continental margin (Veeh et al. 2000) sedimentation rates in the North East Atlantic (McManus et al. 1998 Thomson et al. 1993 ) (Fig. 5) sedimentation rates during key... 

Francois R, Bacon MP, Suman DO (1990) Thorium 230 profiling in deep-sea sediments high resolntion records of flux and dissolution of carbonate in the equatorial Atlantic during the last 24,000 years. Paleoceanography 5(5) 761-787... 

Spencer DW, Bacon MP, Brewer PG (1981) Models of the distribution of " b in a section across the North Equatorial Atlantic Ocean. J Mar Res 39(1) 119-137 Staubwasser M, Henderson GM, Berkman PA, Hall BL (in press) Ba, Ra, Th and U in marine mollusc shells and the potential of Ra/Ba dating of Holocene marine carbonate shells. Geochim Cosmochim... 

Wakeham SG, Farrington JW, Gagosian RB, Lee C, DeBaar H, Nigrelli GE, Tripp BW, Smith SO, Frew NM (1980) Organic-matter fluxes from sediment traps in the equatorial Atlantic-Ocean. Nature 286 798-800... 

Lee, C., and C. Cronin. 1982. The vertical flux of particulate organic nitrogen in the sea decomposition of amino acids in the Peru upweUing area of the equatorial Atlantic. Journal of Marine Research 40 227-251. 

Representative euphotic zone depth profiles of DIN ( j,MN) in waters where ammonium was present. Shown are concentrations of nitrate, nitrite, and ammonium. The SUPREA cruise was conducted in August-September 1978 in the equatorial Atlantic Ocean off the Ivory Coast. 

Marty JC, Saliot A, Aerosols in equatorial Atlantic air -alkanes as a function of particle size. Nature 298 144—147, 1982. 

Suhre, K., J.-P. Cammas, P. Nedelec, R. Rosset, A. Marenco, and H. G. J. Smit, Ozone-Rich Transients in the Upper Equatorial Atlantic Troposphere, Nature, 388, 661-663 (1997). 

Yuneva, T.V., Shulman, G.E., Shchepkina, A.M. and Melnikov, V.V. (1992). The lipid composition of euphausids from the equatorial Atlantic (In Russian). Gydrobiologicheskii Zhumal 28,61-67. 

A detailed study of the chemistry of pore waters near the sediment-water interface of sediments from the equatorial Atlantic was conducted by Archer et al. (1989) using microelectrodes that were slowly lowered into the sediment. By modeling the resulting data they were able to confirm that calcite was dissolving above the saturation depth as a result of benthic oxidation of organic matter. The estimated in situ rate constant for calcite dissoluton was 1-100% day1. This rate constant is 10 to 100 times slower than the one used in previous models, which was based on experimental data. If the slower rate constant proves to be correct, then dissolution of calcite by benthic metabolic processes will be of major importance. 

Curry W.B. and Lohmann G.P. (1985) Carbon deposition rates and deep water residence time in the equatorial Atlantic Ocean throughout the last 160,000 years. In The Carbon Cycle and Atmospheric CO2 Natural Variations Archean to Present (eds. E.T. Sundquist and W.S. Broecker), pp. 285-301. Amer. Geophys. Union, Washington, D.C. 

Curry W.B. and Lohmann G.P. (1986) Late quaternary carbonate sedimentation at the Sierra Leone Rise (eastern equatorial Atlantic Ocean). Mar. Geol. 70, 223-250. 

Seba, D.B. Prospero, J.M. Pesticides in the lower atmosphere of the northern equatorial Atlantic Ocean. Atmos. Environ., 1971, 5, 1043. 

CoUos, Y., and Slawyk, G. (1983). Ammonium and nitrate in the tropical and equatorial Atlantic Relations with the primary nitrite maximum. Mar. Biol. Lett. 4, 295—308. 

Le BouteUler, A. (1986). Environmental control of nitrate and ammonium uptake by phytoplankton in the Equatorial Atlantic Ocean. Mar. Ecol. Prog. Ser. 30, 167-179. 

In the equatorial Atlantic, surface nitrate concentrations vary seasonally with the rate of upweUing. Measurable nitrate is present in the east during the boreal summer but apparendy absent year-round in the west (Oudot and Morin, 1987). 

Bender, M., Panning, K. A., Proelich, P. M., Heath, G. R., and Maynard, V. (1977). Interstitial nitrate profiles and oxidation of sedimentary organic matter in the eastern equatorial Atlantic. Science 198, 605-609. 

Powell R. T. and Donat J. R. (2001) Organic complexation and speciation of iron in the South and equatorial Atlantic. Deep-Sea Res. II48, 2877-2893. 

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 14 The " C-CaCOs age of the sediment bioturbated layer as a function of water depth on the Ontong-Java Plateau (X) in the western equatorial Pacific (Broecker et al., 1999) and the Sierra Leone Rise (O) in the eastern equatorial Atlantic (DuBois and Prell, 1988). The arrows indicate the depth of the first signs of CaC03 dissolution in the sediments as based on %CaC03 (for the Pacific) and %CaC03 fragments (for the Atlantic).

The first uses of radiocarbon in deep-sea core dating were based on few data points and depended on extrapolation assuming the constant rate of titanium deposition (Arrhenius et al., 1951) or interpolation (Suess, 1956) for determination of rates of accumulation and chronology. The first systematic study of radiocarbon incorporating possible changes in accumulation rates with depth in a core was performed by Broecker et al. (1958). They showed that accumulation rates of both the carbonate fraction and the detrital fraction varied with time in the equatorial Atlantic and those variations were linked to paleoclimatic indicators inferred from paleontologic data (Figure 3). 

Francois R. and Bacon M. P. (1991) Variations in terrigenous input into the deep equatorial Atlantic during the past 24,000 years. Science 251, 1473-1476. 

---