Alkenone-based decadal scale temperature reconstruction of the late Holocene from Kongressvatnet, Svalbard
Abstract
As part of a Research Experience for Undergraduates (REU) program held during the Summer of 2009, three cores as well as data from level loggers and temperature loggers were retrieved from a small lake on the island of Spitsbergen, Svalbard. Kongressvatnet is a 48-meter deep 0.82 km2 meromictic lake situated 94 m above sea level. A sharp chemocline is located approximately five meters from the bottom of the lake below which water contains hydrogen sulfide. These conditions preserve annual varves extending back at least 2,000 years. Long-chain alkenones (LCAs) have been isolated from these sediments. These LCAs are only produced by certain members of the algal class Prymnesiophyceae. Thus, C37 alkenones discovered in Kongressvatnet may be employed in the alkenone unsaturation index UK37 as a paleotemperature indicator. This study provides an interesting test to develop an alkenone based paleotemperature record in high latitude lake sediments. Decadally resolved alkenone unsaturation index paleotemperatures are compared with the meteorological record from the airport in Longyearbyen (40 km away). This study takes advantage of one of the longest continuous meteorological records in the High Arctic dating to 1912, to investigate how well LCAs track summer temperature changes as proposed in previous lacustrine studies. Lake sediment chronology is determined using 210Pb dating as well as correlations of unique chemical signatures and distinct lithological characteristics with previous studies. Upon completion of the REU, an alkenone unsaturation index record (UK37) will be produced, documenting proxy derived high-resolution summer temperature fluctuations of Svalbard beyond the meteorological record through the Little Ice Age (LIA), which began during the mid-1300s AD on Svalbard.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFMPP41C1533V
- Keywords:
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- 0473 BIOGEOSCIENCES / Paleoclimatology and paleoceanography;
- 1616 GLOBAL CHANGE / Climate variability;
- 1616 GLOBAL CHANGE / Climate variability;
- 9315 GEOGRAPHIC LOCATION / Arctic region