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| Titel |
Off to new shores: Modeling the potential distribution and future range expansion of larger foraminifera |
| VerfasserIn |
A. E. Weinmann, D. Rödder, S. Lötters, M. R. Langer |
| 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 |
250060492
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| Zusammenfassung |
| The distribution of larger foraminifera is strongly controlled by environmental variables,
especially temperature. Most of today’s taxa of larger foraminifera are restricted to tropical
and subtropical regions (between 30Ë Â N and 30Ë Â S) and their minimum temperature limits
are governed by the 14 to 20Ë C isotherms. However, during times of extensive global
warming (e.g. the Eocene and Miocene), larger foraminifera have been found as far North as
50Ë N (North America and Central Europe) as well as towards 40Ë Â S in New Zealand. It
has been stated that larger foraminifera are more tolerant of rising sea surface temperatures
than reef-building corals. As such they may play a more prominent role as future reef
framework and carbonate producers in a steadily warming ocean. During the last
century, sea surface temperatures have been rising significantly due to higher CO2
concentrations in the atmosphere. This trend is expected to continue and climate change
scenarios for 2100 suggest a further increase by 1 to 6Ë C (IPCC Synthesis Report,
2007).
We applied Species Distribution Models (SDMs) on several taxa of larger foraminifera
in order to evaluate their potential distribution under current climate conditions
and to predict range expansions within the next 40 years. The studied taxa include
Archaias angulatus, which is regionally distributed within the Caribbean region,
Calcarina spp., which occurs in the Indo-Pacific area and the true circumglobal taxon
Amphistegina spp. Under present climate, Amphistegina spp. shows the widest
distribution range due to its greater temperature tolerance. Both Archaias angulatus
and Calcarina spp. display potential distributions that cover currently uninhabitet
regions, suggesting that weak dispersal abilities are major reasons for their limited
distributions. Under future climate, Archaias angulatus and Calcarina spp. show an
increase in habitat suitability within their native occurrence ranges, suggesting
that their tolerance for maximum temperatures has not been fully exploited yet.
Furthermore, all taxa display an expected latitudinal range expansion by 1 to 3
degrees both north- and southward. Our findings suggest an increased role of larger
foraminifera as carbonate producers and reef framework builders as well as the
colonization of biogeographic regions so far unsuitable for larger foraminifera. |
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