Calcareous Dinoflagellate Cysts as Paleo-Environmental Tools
K.A.F. Zonneveld*, C. Holl, D. Janofske, B. Karwath, B. Kemtopf,
C. Rlihlemann and H. Willems
Universitat Bremen, Fachbereich Geowissenschafien, Postfach 33 0440,
D-28334 Bremen, Germany
*corresponding author (e-mail):zonnev@uni-bremen.de
Abstract: An overview is presented ofthe current state of knowledge on paleo-ecological aspects
of calcareous dinoflagellate resting cysts. Apart from literature-based information, a discussion of
new results is also provided from Equatorial Atlantic surface plankton samples, surface sediment
samples and Late Quaternary sediments from two gravity cores. With the aid of redundancy analysis statistics, variations in the calcareous cyst content of both cores are correlated to variations in
total organic carbon (TOC). On a global scale, the calcareous cyst distribution in bottom sediments
varies with latitude and inshore-offshore gradients. In the Equatorial Atlantic Ocean, enhanced
calcareous cyst production can be observed in regions and time intervals with stratified, oligotrophic
conditions in the upper water masses.
Introduction
During the last decade it has become evident
that variations in (paleo-) ocean circulation and
(paleo-) productivity in the South Atlantic Ocean,
have had a major influence on the world's climate
(e.g. Wefer et al. 1996b). In order to obtain an
estimate of this influence, it is essential to establish detailed paleoceanographic reconstructions of
the South Atlantic. In spite ofthe increasing interest in this particular ocean, the reconstructions presently available are still under debate and sometimes stand in conflict with each other (e.g. van
Langeveldetal. 1978; Schneideretal. 1995; 1996;
Billups and Spero 1996; Boyle and Rosenthal 1996;
WeferetaI.1996a). This conflict might result from
the fact that reconstructions are often based on fossil
organisms. Since every group of organisms has its
own ecological niche, their fossil remains reflectthe
environmental conditions of that particular niche
only. Furthermore, until now, few groups of organisms have been studied in detail. Consequently, only
part of the paleo-environmental information required for such paleoceanographic reconstructions
is presently available.
A group of organisms that has generally been
overlooked in the past is that ofthe calcareous cyst
forming dinoflagellates (Table I). As result oftheir
cyst-size between about 20-60 )lm they appear to
be too small to have been included in foraminiferal
studies and too large for studies of the nannoplankton community. Furthermore, they dissolve in
the course of preparation for studies on palynological
residues. In fossil strata, calcareous dinoflagellate
cysts have been present at least since the Upper
Triassic (e.g. Janofske 1992). In Cretaceous times
they can account for over 80% of the sediment (e.g.
Willems 1988, 1992, 1996). Recent studies on sediment trap material have shown that, even today,
calcareous dinoflagellate cysts form a considerable
flux from surface waters to the deep-sea in the
particle size fraction between 20 and 125 )lm (Dale
and Dale 1992; Dale 1992a). As such, they may
form a significant, and as yet probably
underestimated contribution to the total carbonate
flux down to the ocean floor.
In order to develop the full potential of calcareous dinoflagellate cysts as tools for paleo-oceanoFrom FISCHER G, WEFER G (eds), 1999, Use of Proxies in Paleoceanography: Examplesfrom the South Atlantic. Springer-Verlag
Berlin Heidelberg, pp 145-164
K.A.F. Zonneveld*, C. Holl, D. Janofske, B. Karwath, B. Kemtopf,
C. Rlihlemann and H. Willems
Universitat Bremen, Fachbereich Geowissenschafien, Postfach 33 0440,
D-28334 Bremen, Germany
*corresponding author (e-mail):zonnev@uni-bremen.de
Abstract: An overview is presented ofthe current state of knowledge on paleo-ecological aspects
of calcareous dinoflagellate resting cysts. Apart from literature-based information, a discussion of
new results is also provided from Equatorial Atlantic surface plankton samples, surface sediment
samples and Late Quaternary sediments from two gravity cores. With the aid of redundancy analysis statistics, variations in the calcareous cyst content of both cores are correlated to variations in
total organic carbon (TOC). On a global scale, the calcareous cyst distribution in bottom sediments
varies with latitude and inshore-offshore gradients. In the Equatorial Atlantic Ocean, enhanced
calcareous cyst production can be observed in regions and time intervals with stratified, oligotrophic
conditions in the upper water masses.
Introduction
During the last decade it has become evident
that variations in (paleo-) ocean circulation and
(paleo-) productivity in the South Atlantic Ocean,
have had a major influence on the world's climate
(e.g. Wefer et al. 1996b). In order to obtain an
estimate of this influence, it is essential to establish detailed paleoceanographic reconstructions of
the South Atlantic. In spite ofthe increasing interest in this particular ocean, the reconstructions presently available are still under debate and sometimes stand in conflict with each other (e.g. van
Langeveldetal. 1978; Schneideretal. 1995; 1996;
Billups and Spero 1996; Boyle and Rosenthal 1996;
WeferetaI.1996a). This conflict might result from
the fact that reconstructions are often based on fossil
organisms. Since every group of organisms has its
own ecological niche, their fossil remains reflectthe
environmental conditions of that particular niche
only. Furthermore, until now, few groups of organisms have been studied in detail. Consequently, only
part of the paleo-environmental information required for such paleoceanographic reconstructions
is presently available.
A group of organisms that has generally been
overlooked in the past is that ofthe calcareous cyst
forming dinoflagellates (Table I). As result oftheir
cyst-size between about 20-60 )lm they appear to
be too small to have been included in foraminiferal
studies and too large for studies of the nannoplankton community. Furthermore, they dissolve in
the course of preparation for studies on palynological
residues. In fossil strata, calcareous dinoflagellate
cysts have been present at least since the Upper
Triassic (e.g. Janofske 1992). In Cretaceous times
they can account for over 80% of the sediment (e.g.
Willems 1988, 1992, 1996). Recent studies on sediment trap material have shown that, even today,
calcareous dinoflagellate cysts form a considerable
flux from surface waters to the deep-sea in the
particle size fraction between 20 and 125 )lm (Dale
and Dale 1992; Dale 1992a). As such, they may
form a significant, and as yet probably
underestimated contribution to the total carbonate
flux down to the ocean floor.
In order to develop the full potential of calcareous dinoflagellate cysts as tools for paleo-oceanoFrom FISCHER G, WEFER G (eds), 1999, Use of Proxies in Paleoceanography: Examplesfrom the South Atlantic. Springer-Verlag
Berlin Heidelberg, pp 145-164