@Article{LessaMJVRBAK:2019:DeHiCo,
author = "Lessa, Douglas and Morard, Raphael and Jonkers, Lukas and
Ven{\^a}ncio, Igor Martins and Reuter, Runa and Baumeister,
Adrian and Albuquerque, Ana Luiza and Kucera, Michal",
affiliation = "{University of Bremen} and {University of Bremen} and {University
of Bremen} and {Instituto Nacional de Pesquisas Espaciais (INPE)}
and {University of Bremen} and {University of Bremen} and
{Universidade Federal Fluminense (UFF)} and {University of
Bremen}",
title = "Vertical distribution of planktonic foraminifera in the
Subtropical South Atlantic: depth hierarchy of controlling
factors",
journal = "Biogeosciences Discussions",
year = "2019",
volume = "2019",
number = "355",
abstract = "Temperature appears to be the best predictor of species
composition of planktonic foraminifera communities, making it
possible to use their fossil assemblages to reconstruct sea
surface temperature (SST) variation in the past. However, the role
of other environmental factors potentially modulating the spatial
and vertical distribution of planktonic foraminifera species is
poorly understood. This is especially relevant for environmental
factors affecting the subsurface habitat. If such factors play a
role, changes in the abundance of deeper dwelling species may not
solely reflect SST variation. In order to constrain the effect of
subsurface parameters on species composition, we here characterize
the vertical distribution of living planktonic foraminifera
community across the subtropical South Atlantic Ocean, where SST
variability is small but the subsurface water mass structure
changes dramatically. Four planktonic foraminifera communities
could be identified across the top 700\ m of the EW
transect. Gyre and Agulhas Leakage faunas were predominantly
composed of Globigerinoides ruber, Globigerinoides tenellus,
Trilobatus sacculifer, Globoturborotalita rubescens,
Globigerinella calida, Tenuitella iota and Globigerinita
glutinata, and only differed in terms of relative abundances
(community composition). Upwelling fauna was dominated by
Neogloboquadrina pachyderma, Neogloboquadrina incompta,
Globorotalia crassaformis and Globorotalia inflata. Thermocline
fauna was dominated by Tenuitella fleisheri, Globorotalia
truncatulinoides and Globorotalia scitula in the western side, and
by G. scitula in the eastern side of the basin. The largest part
of the standing stock was consistently found in the surface layer,
but SST was not the main predictor of species composition, neither
for the total fauna at each station nor in analyses considering
each depth layer separately. Instead, we identified a consistent
vertical pattern in parameters controlling species composition at
different depths, in which the parameters appear to reflect
different aspects of the pelagic habitat. Whereas productivity
appears to dominate in the mixed layer (060\ m),
physical-chemical parameters are important at depth immediately
below (60100\ m), followed by parameters related to the
degradation of organic matter (100300\ m), and parameters
describing the dissolved oxygen availability
(>\ 300\ m). These results indicate that the
seemingly straightforward relationship between assemblage
composition and SST in sedimentary assemblages reflects vertically
and seasonally integrated processes that are only indirectly
linked to SST. This also implies that fossil assemblages of
planktonic foraminifera should also contain a signature of
subsurface processes, which could be used for paleoceanographic
reconstructions.",
doi = "10.5194/bg-2019-355",
url = "http://dx.doi.org/10.5194/bg-2019-355",
issn = "1810-6277",
language = "en",
targetfile = "lessa_vertical.pdf",
urlaccessdate = "28 abr. 2024"
}