 |
| Titel |
Sub-seasonally resolved coral records of northern Red Sea - eastern Mediterranean climate during the Holocene and the last interglacial |
| VerfasserIn |
T. Felis, N. Rimbu, S. Al-Rousan, H. Kuhnert, G. Lohmann, M. Kölling, J. Pätzold |
| Konferenz |
EGU General Assembly 2012
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250062423
|
|
|
|
|
|
| Zusammenfassung |
| The northern Red Sea represents a unique location where ocean currents transport warm
tropical waters northward, enabling coral reef growth at unusually high latitudes of up to 29 Ë
N. Moreover, one of the world’s northernmost complexes of uplifted Pleistocene reef
terraces can be found here at Aqaba (Jordan). We present sub-seasonally resolved
reconstructions of surface ocean conditions in the northern Red Sea derived from
annually banded Porites corals. The Sr/Ca and δ18O variations in the aragonitic
skeletons of our modern and fossil coral colonies provide proxy records of temperature,
salinity and hydrologic balance at the sea surface during the last centuries and during
time windows (40 to 100 years length) of the Holocene and the last interglacial
period. Previous work has shown that seasonality and interannual to decadal climate
variability in the northern Red Sea as documented in our coral records is strongly
coupled to climate variations in the eastern Mediterranean, Middle East and Europe,
reflecting the prominent role of atmospheric teleconnections of the Arctic Oscillation
(AO)/North Atlantic Oscillation (NAO) in controlling regional climate on these
timescales.
New coral Sr/Ca data, in combination with δ18O, reveal an abrupt regime shift toward
fresher surface ocean conditions in northern Red Sea surface waters at the end of the Little
Ice Age. Possible mechanisms include a re-organization of the Northern Hemisphere
atmospheric circulation. Sr/Ca records from a large number of fossil corals indicate a trend of
decreasing temperature seasonality over the last 6000 years toward present-day.
Such a trend is expected in the higher latitudes of the Northern Hemisphere from
insolation changes on orbital timescales. Coral δ18O and Sr/Ca records suggest an
increased seasonality in the hydrologic balance during time intervals around 4400, 4600
and 6000 years ago, which could result from both enhanced winter evaporation or
increased summer precipitation, although the latter is rather unlikely in this arid
region. We currently generate century-long δ18O and Sr/Ca records from large
fossil corals, in order to reconstruct northern Red Sea temperature, salinity and
hydrologic balance at sub-seasonal resolution during time windows (up to 170
years length) of the last 2000 to 3000 years, and during shorter time windows of the
last interglacial. The paleoclimatic potential of recently collected fossil corals of
Holocene and last interglacial age from the northern Gulf of Aqaba will be discussed. |
|
|
|
|
|
|