@Article{LessaSantVanaAlbu:2017:OfExBr,
author = "Lessa, Douglas V. O. and Santos, Thiago P. and Vanancio, Igor
Martins and Albuquerque, Ana Luiza S.",
affiliation = "{Universidade Federal Fluminense (UFF)} and {Universidade Federal
Fluminense (UFF)} and {Instituto Nacional de Pesquisas Espaciais
(INPE)} and {Universidade Federal Fluminense (UFF)}",
title = "Offshore expansion of the Brazilian coastal upwelling zones during
Marine Isotope Stage 5",
journal = "Global and Planetary Change",
year = "2017",
volume = "158",
pages = "13--20",
month = "Nov.",
keywords = "UpwellingPlanktonic foraminiferaBrazil
CurrentEccentricityPaleoceanography.",
abstract = "Paleoceanographic reconstructions in upwelling regions can provide
relevant information about changes in primary productivity,
oceanatmosphere interactions and the carbon budget. Here, we
assessed new data on planktonic foraminifera from a sediment core
located near to coastal upwelling zones along the Brazilian coast.
Our new data was combined with previous records to reveal the
state of upwelling systems along the western South Atlantic margin
throughout the last two deglacial and interglacial periods sensu
lato. Despite the contemporary oligotrophic scenario of the Santos
Basin, a remarkably high relative abundance of Globigerina
bulloides and low temperatures at a depth of 100 m indicated
upwelling conditions similar to current shelf upwelling zones from
130 to 90 kyr BP. Comparing these results with previous studies,
we argue that Brazilian shelf upwelling zones expanded offshore
between 20 and 28°S. We develop two conceptual scenarios to
characterize the system: (1) during Marine Isotopic Stage (MIS 5),
the system expanded along the continental margin between 20 and
28°S following the eccentricity maximum; and (2) after 20 kyr BP,
the system retracted to current continental shelf zones. We
propose a new mechanism whereby variation of the Earth's
eccentricity, which drives seasonality, is the main factor
controlling expansion or retraction of the Brazilian upwelling
system. Absence of such conditions in more recent periods supports
our model and indicates that current upwelling zones are the
remnants of a larger upwelling system. However, more studies are
required to better define the latitudinal boundaries of the
Brazilian upwelling system in the past and its possible influences
over the regional carbon budget.",
doi = "10.1016/j.gloplacha.2017.09.006",
url = "http://dx.doi.org/10.1016/j.gloplacha.2017.09.006",
issn = "0921-8181",
language = "en",
targetfile = "lessa_offshore.pdf",
urlaccessdate = "27 abr. 2024"
}