In:
Climate of the Past, Copernicus GmbH, Vol. 18, No. 1 ( 2022-01-20), p. 89-101
Abstract:
Abstract. Individual foraminifera analysis (IFA) holds promise to reconstruct seasonal
to interannual oceanographic variability. Even though planktonic foraminifera
are reliable recorders of environmental conditions on a population level,
whether they also are on the level of individuals is unknown. Yet, one of the
main assumptions underlying IFA is that each specimen records ocean conditions
with negligible noise. Here we test this assumption using stable isotope data
measured on groups of four shells of Neogloboquadrina pachyderma from
a 16–19 d resolution sediment trap time series from the subpolar
North Atlantic. We find a within-sample variability of 0.11 ‰
and 0.10 ‰ for δ18O and δ13C
respectively that shows no seasonal pattern and exceeds water column variability
in spring when conditions are homogeneous down to hundreds of metres. We assess
the possible effect of life cycle characteristics and delay due to settling on
foraminifera δ18O variability with simulations using
temperature and δ18Oseawater as input. These
simulations indicate that the observed δ18O variability can
only partially be explained by environmental variability. Individual
N. pachyderma are thus imperfect recorders of temperature and
δ18Oseawater. Based on these simulations, we
estimate the excess noise on δ18O to be 0.11±0.06 ‰. The origin and nature of the recording imprecision
require further work, but our analyses highlight the need to take such excess
noise into account when interpreting the geochemical variability among
individual foraminifera.
Type of Medium:
Online Resource
ISSN:
1814-9332
DOI:
10.5194/cp-18-89-2022
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2022
detail.hit.zdb_id:
2217985-9
