Considering Schmidt (1999) SCHMIDT GA, BIGG GR and you can ROHLING EJ
In oceanic regions with a positive E-P (Evaporation-Precipitation) balance, there is enrichment in the superficial ocean layer due to preferential evaporation of the lighter species ( Meredith MEREDITH MP, GROSE KE, MCDONAGH EL, HEYWOOD KJ, FREW RD and DENNIS PF. 1999. J Geophys Res Oceans (1978–2012) 104(C9): 20949-20962. et al. 1999). On the other hand, river discharges, high precipitation and ice melting are related to regions with depleted values of ? 18 Osw ( Redfield REDFIELD AC and FRIEDMAN I. 1965. Factors affecting the distribution of deuterium in the ocean. In Symposium on Marine Geochemistry. Rhode Island University Narragansett Marine Laboratory Occasional Publication, Vol. 3, p. 149-168. and Friedman 1965). On a geologic time scale, the glacial boundary conditions influence the isotopic composition of the oceans due to the storage of lighter ? 18 O and ?D isotopes in the ice sheets, which is known as global ice volume effect. However, during interglacial periods, this effect was reversed (Holloway et al. 2015).
Because salinity and ? 18 Osw are controlled by the same processes, they show a quasi-linear relationship, and the slope is dependent on the kinetic processes acting in the water mass formation area. 2015. Differences among subtropical surface salinity patterns. Oceanogr 28(1): 32-39. 1965). 1999. Global Seawater Oxygen-18 Database – v1.21. , the global mixing line between ? 18 Osw and salinity can be used as an approximation only in mid to high latitudes, since the scatter for the tropical samples could be up to 0.13‰. Therefore, regional mixing lines become essential pieces in paleoclimatic studies in the equatorial and tropical regions. Holloway et al. (2015) suggested that regions with marked variability in the evaporation-precipitation budget and strong oceanographic dynamics need additional constraints to establish good salinity and ? 18 Osw relationships on spatial and temporal scales. On the other hand, South Atlantic, Indian and Tropical Pacific Oceans have more reliable paleosalinity reconstructions without the need of additional constraints.
Despite the importance of the Southwest Atlantic Ocean for thermohaline circulation and the global climate through in the South Atlantic Meridional Overturning Circulation (SAMOC), only a few studies have been carried out in this area using stable isotopes. For example, GEOSECS was conducted in the South Atlantic focusing on open waters (Kroopnick 1980, Ostlund OSTLUND HG, CRAIG H, BROECKER WS and SPENCER D. 1987. GEOSECS Atlantic, Pacific and Indian ocean expeditions, shorebased data and graphics, Vol. 7. Technical report, I.D.O.E. National Science Foundation, p. 200. et al. 1987) and an independent work of Pierre et al. (1991) focused on a small offshore area of the southwestern Atlantic. None of these papers were focused on paleoclimatic applications. The aim of the present study was to investigate the distribution of the stable isotopes (? 18 Osw and ?Dsw) at the Western Tropical South Atlantic border, from the continental shelf to slope, in order to better understand the main fractionation processes of these isotopes and establish a regional salinity and ? consejos tsdates 18 Osw relationship to improve paleoceanographic knowledge in the study region.
Upcoming, pursuing the drinking water mass basins, the partnership stays stable throughout the water bulk lives (Craig and you can Gordon GORDON AL, GIULIVI CF, BUSECKE J and you will BINGHAM FM
The new eastern Brazilian continental margin is normal for its reduced width and you will shallow depths in comparison to other areas of the Southwest Atlantic margin, due to reduced continental erosion speed plus the short area of marine sedimentation. As well, the constant visibility of your own Brazil Newest flowing toward southwest parallel to the bookshelf while the Northern Brazil Current streaming equatorward moving loving and you will saline Tropical Liquids offers the part an essentially oligotrophic reputation, which decreases the new genesis out of biogenic situation that comprise extremely of the sedimentary bottoms about southeastern Brazilian continental shelf ( Knoppers KNOPPERS B, EKAU W and FIGUEIREDO AG. 1999. This new shore and you may bookshelf regarding eastern and you may northeast Brazil and you can topic transportation. Geo-Marine Lett 19: 171. ainsi que al. 1999). The brand new bifurcation of one’s Southern Equatorial Latest (SEC) takes place at about ten°–14°S around the body as well as the continental bookshelf width varies from 42 kilometres out of Maceio to eight kilometer regarding Salvador, having on average 30 kilometer ( Fig. 1).
