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| Titel |
Chironomid oxygen isotope record of mid- to late Holocene climate evolution
from southern Spitsbergen |
| VerfasserIn |
Laura Arppe, Eija Kurki, Matthew Wooller, Tomi Luoto, Marek Zajączkowski, Antti Ojala |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250152478
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| Publikation (Nr.) |
 EGU/EGU2017-17319.pdf |
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| Zusammenfassung |
| The oxygen isotope composition of head capsule chitin of chironomid larvae picked from a
sediment core covering the past 5500 years from lake Svartvatnet in southern Spitsbergen
was used to reconstruct the isotopic composition of oxygen in lake water (δ18Olw)
and local precipitation. Consistent with the gradual cooling of climate over the
Neoglacial period, the δ18Olw record displays a gentle decreasing trend over the
study period. The Svartvatnet δ18Olwrecord shows a maximum at ca. 1900-1800
cal BP, consistent with the timing of the Roman Warm Period, and three negative
excursions increasing in intensity towards the present-day at 3400-3200, 1250-1100
and 350-50 cal BP, which are tentatively linked to multidecadal periods of low
solar activity amplified by oceanic and atmospheric feedbacks. The time period of
the Little Ice Age shows a two-step decrease in δ18Olwvalues, with a remarkable,
8-9‰ drop at 350-50 cal BP construed to predominantly represent significantly
decreased winter temperatures during a period of increased seasonal differences and
extended sea ice cover inducing changes in moisture source regions. Similarity of the
trends between the δ18Olwrecord and a July-T reconstruction based on chironomid
assemblages (Luoto et al., in review) from the same core suggests that air temperature
exerts a significant control over the δ18Olwvalues, but the record is most likely
influenced by changes in sea ice extent and possibly the seasonal distribution of
precipitation.
Reference: Luoto TP, Ojala A, Brooks S et al. Synchronized proxy-based temperature
reconstructions reveal mid-to late Holocene climate oscillations in High Arctic Svalbard.
Journal of Quaternary Science, submitted. |
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