- This atlas shall be a tool to communicate microfossil ecology
and applications of planktic foraminifera to the students, to
support differentiated interpretations of microfossil assemblages
in professional research, and to show underlying causes of biogeographic
pattern in the relationships of species with the physical environment
and its seasonal variation. The atlas makes use of the extensive
data collected by the CLIMAP project and Levitus (1982). It has
been compiled as a graphical visualisation of the relationships
of relative abundances of modern planktic foraminifera and the
physical environment. This approach seemed necessary because
most large data sets in this field have been reduced through
multivariate statistical methods. The mathematical treatment
allows for fast and easy access of results but it also hides
structure in the data and presents mathematical problems where
the relationships of relative abundances and physical parameters
follow complicated distribution pattern. It is this complicated
pattern, however, that is characteristic for some species. The
graphic approach is demanding. The reader has to extract information
from numerous plots of relative abundance vs. physical parameters.
Through this effort the reader will experience the multivariate
character of ecological relationships in planktic foraminifera.
Their distribution follows a combination of parameters that are
characteristic for the individual niches of species. The graphic
approach allows to access and to discuss these relationships
in a less abstract form than in output from a multivariate statistical
procedure.
Planktic foramnifera belong to the most intensely studied
groups of geologically relevant organisms and, therefore, much
is known about their ecology at least on a qualitative scale.
This concerns mostly biogeographic pattern which has been summarised
and reviewed in numerous papers. This atlas will necessarily
reproduce some of this information but may help to extract more
information from the published maps of biogeographic distributions
and statistical data. The brief descriptions of the plots for
every species shall help to see relevant pattern in the plots.
They are not intended as a comprehensive review of the ecology
of these species and of the literature published on this subject.
Previous studies were mostly focussed on relations of planktic
foraminifera with the properties of surface waters. I included
the conditions at 200 m depth in the analysis. At this depth
the seasonal variation is neglectable and results can give an
insight in effects of contrasts between the mixed layer and the
central waters. The plots show close relationships of relative
abundances of numerous deeper dwelling species with the seasonally
variable stratification in the upper ocean. This observation
may be used in paleoceanographic work and other new applications
of planktic foraminifera. It may also help to interpret isotope
data from some species that have to be seen in the light of preferences
for certain oceanographic conditions and their seasonal variation.
Zürich, August 1996
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