@Article{PiacsekBeGuVeLeBeAl:2021:ChSeSu,
               author = "Piacsek, Patr{\'{\i}}cia and Behling, Hermann and Gu, Fang and 
                         Venancio, Igor Martins and Lessa, Douglas V. O. and Belem, 
                         Andr{\'e} and Albuquerque, Ana Luiza S.",
          affiliation = "{Universidade Federal Fluminense (UFF)} and {University of 
                         Goettingen} and {University of Goettingen} and {Instituto Nacional 
                         de Pesquisas Espaciais (INPE)} and {Universidade Federal 
                         Fluminense (UFF)} and {Universidade Federal Fluminense (UFF)} and 
                         {Universidade Federal Fluminense (UFF)}",
                title = "Changes in sea surface hydrography and productivity in the western 
                         equatorial Atlantic since the last interglacial",
              journal = "Palaeogeography, Palaeoclimatology, Palaeoecology",
                 year = "2021",
               volume = "562",
                pages = "e109952",
                month = "Jan.",
             keywords = "Dinoflagellate, Glacial-Interglacial, Intertropical Convergence 
                         Zone, Heinrich Stadials.",
             abstract = "Scientific projections point to the increase of greenhouse gas 
                         levels in the atmosphere will turn the oceans warmer and, 
                         consequently, the upper layer of the thermohaline circulation will 
                         get thicker, restricting the productivity areas. Oligotrophic 
                         conditions will tend to prevail, and expanding the range of proxy 
                         data in oligotrophic oceans, across different climate scenarios, 
                         has the potential to improve predictions of climate models about 
                         how primary productivity will respond. Still, the variability of 
                         past primary production in the equatorial Atlantic remains 
                         elusive. We used organic-walled dinoflagellate cysts (dinocysts) 
                         assemblages to reconstruct changes in the sea surface hydrography 
                         and productivity in the western equatorial Atlantic over the last 
                         similar to 130 kyr. Four dinocysts assemblages were defined: open 
                         ocean, river outflow, neritic and nutricline assemblages. Multiple 
                         proxies were used to support the environmental changes evidenced 
                         by the observed variations in the dinocyst assemblages, such as 
                         the X-ray fluorescence (XRF) Ti/Ca ratio, and planktonic 
                         foraminifera abundances. We observed glacial-interglacial as well 
                         as the millennial-scale changes in the dinocyst assemblages. A 
                         clear glacial-interglacial pattern was marked by more autotrophs 
                         dinocysts over the interglacials and the prevalence of 
                         heterotrophs dinocysts during the glacial period. We pointed out 
                         the interchange of autotrophs assemblages (nutricline and open 
                         ocean) over the interglacials intervals, denoting divergences in 
                         nutrient availability. During the last glacial period, 
                         precipitation events occurred in northeastern Brazil due to 
                         southward displacements of the Intertropical Convergence Zone 
                         (ITCZ). The increase of precipitation boosted the freshwater input 
                         to the adjacent ocean, and the dinocyst assemblages oscillated in 
                         response to such freshwater/salinity changes. Over the glacial 
                         period, dinocysts with different nutritional requirements 
                         (autotrophs and heterotrophs) varied following the ITCZ 
                         displacements. Thus, in this study, we showed the influence of 
                         ocean-atmospheric processes on the ocean and investigated the 
                         productivity in an oligotrophic region over distinct past climatic 
                         backgrounds.",
                  doi = "10.1016/j.palaeo.2020.109952",
                  url = "http://dx.doi.org/10.1016/j.palaeo.2020.109952",
                 issn = "0031-0182",
             language = "en",
           targetfile = "piacsek_changes.pdf",
        urlaccessdate = "21 maio 2024"
}