Τίτλος:
Latitudinal Variation of Planktonic Foraminifera Shell Masses During
Termination I
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
The oceans’ surface layer holds large amounts of dissolved inorganic
carbon that is exchanged rapidly with the atmosphere. Carbon enters the
ocean mainly through the dissolution of atmospheric carbon dioxide
(CO2), and a part of it is converted into carbonate by marine organisms.
Calcifying marine organisms include planktonic foraminifers that
contribute to the marine carbon turnover by generating inorganic carbon
production (CaCO3 shells). Anthropogenic CO2 acidifies the surface
ocean, changes the carbonate chemistry and decreases the saturation
state of carbonate minerals in sea water, thus affecting the biological
precipitation of carbonate shells. Relative changes in average
foraminiferal shell mass can be interpreted as variations in test
thickness and the extent of calcification that subsequently impacts the
global carbonate budgets. The response of calcifying marine organisms to
elevated atmospheric pCO(2) is diverse and complex with studies
reporting from reduced rates of net calcification to neutral receptivity
or even increased calcification intensities. This diverse behavior
implies that the concentration of dissolved inorganic carbon may not be
the dominant factor controlling the amount of carbonate shell masses.
Here we provide further evidence that glacial/interglacial variations of
planktonic foraminifera shell masses are invariant to atmospheric
pCO(2). We identify that differences in shell weights of several
planktonic foraminiferal species from narrow size intervals, over the
most recent deglaciation (Termination I) vary systematically as a
function of latitude. Past intervals of abruptly changing pCO(2) and
temperatures, such as the terminations, can offer a glimpse into the
response of marine calcifying plankton to changes in surface oceans. We
have compiled all the available bibliographic data of planktonic
foraminifera shell weights from restricted sieve fractions of different
species from the Atlantic, Pacific and Indian Oceans and we find that
for the same pCO(2) conditions planktonic foraminifera from equatorial
regions may alter their shell mass only as little as 8.2%, while
towards higher latitudes changes in shell mass reach up to 54% during
the transition from the last glacial to interglacial conditions. We
attribute this low variability in the shell mass of planktonic
foraminifera from the equator to the stability of the physical
oceanographic conditions that characterize the equatorial zone.
Συγγραφείς:
Zarkogiannis, Stergios D.
Kontakiotis, George
Antonarakou,
Assimina
Graham Mortyn, P.
Drinia, Hara
Εκδότης:
IOP Publishing Ltd
Τίτλος συνεδρίου:
WORLD MULTIDISCIPLINARY EARTH SCIENCES SYMPOSIUM (WMESS 2018)
DOI:
10.1088/1755-1315/221/1/012052
