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| Titel |
The distribution of organic-walled dinoflagellate cysts in marine surface samples of the eastern Indian Ocean in relation to environmental conditions |
| VerfasserIn |
I. Hessler, M. Young, M. Mohtadi, A. Lückge, H. Behling |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250065639
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| Zusammenfassung |
| The eastern Indian Ocean is characterised by a complex system of surface currents that move
according to the monsoon-dominated wind regime and show a strong seasonality. The
Indonesian Throughflow, which originates in the northwestern and tropical Pacific
and passes through the Indonesian archipelago into the Indian Ocean, is the only
low-latitude oceanic connection between the Pacific and Indian Oceans and represents a
key element in the global thermohaline circulation and hence the global climate
system.
In recent decades it has become increasingly important to understand the atmospheric and
oceanographic processes involved in climate variations. Assemblages of organic-walled
dinoflagellate cysts (dinocysts) from marine surface samples provide insights into the
relationship between the spatial distribution of dinocysts and modern local environmental
conditions (e.g. sea surface temperature, sea surface salinity, productivity). These
information are of great value for the interpretation of past variations in surface water
conditions.
We present an extensive data-set of marine surface samples (n=116) from the Eastern
Indian Ocean. The conducted Principal Component Analysis (PCA) illustrates the
variation of species association between the sites and reveals a geographical affinity of
the samples to the regions of (1) Western Indonesia, (2) Java, (3) the Indonesian
Throughflow and (4) Western Australia including the Timor Sea. The results of the
PCA further indicate the existence of two environmental gradients in the study
area, a nutrient gradient increasing from Western Indonesia towards the Indonesian
Throughflow region and a temperature gradient increasing from Western Australia
towards Western Indonesia. The Redundancy Analysis indicates the presence of
three dominating taxa in the sample set, namely Spiniferites spp., Operculodinium
centrocarpum and Brigantedinium spp., and reveals significant correlations of the
three dominant taxa to specific environmental parameter. While Spiniferites spp.
strongly correlates with the silicate concentrations of the surface water between
April and June, O. centrocarpum, T. vancampoae and Impagidinirum species show
a negative correlation with the annual sea surface temperature. Brigantedinium
spp. as well as nearly all other heterotrophic cyst species and L. machaerophorum
show a positive correlation with the chlorophyll-a concentration between July and
September, hence indicating an affinity of these species with seasonal upwelling. |
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