RELATIONSHIPS BETWEEN TERRESTRIAL AND AQUATIC PRODUCTIVITY THROUGH THE LATE-HOLOCENE AT TWO NORTHWEST ICELAND LAKES

The sensitivity of the Arctic to changes in climate makes the region ideal for paloeclimatological studies. Despite the fact that many studies assessing the paleoproductivity of lakes in the Arctic have been conducted, there still remains a gap in understanding of the relationship between a lake and its surrounding watershed.

This study will assess lake and watershed productivity through the late Holocene and their relationship to one another. Lake and watershed paleoenvironmental change will be interpreted by use of δ ¹³C_org, C/N, TN, TOC and δ ¹⁵N. The use of these parameters will allow for the interpretation of changes in autochthonous productivity, terrestrial input, and watershed species composition through the Holocene.

High-resolution samplings of soil profiles representative of surrounding watershed slopes at Rekavikurvatn will be carried out in summer 2013 to accompany Vatnsdalsvatn soil samples taken in July 2011. Watershed productivity will be interpreted from soil samples collected.

A sediment core from Vatnsdalsvatn provides a ~6000 cal yr BP record of past climatic variability. A sediment core to be taken in summer 2013, will provide an accompanying record of past climate variability at Rekavikurvatn. Preliminary results from Vatnsdalsvatn soils show high TOC in upper soil horizons for all valley locations. Sediments from Vatnsdalsvatn also exhibit relatively high TOC values throughout the sediment core. Sediment cores will provide high-resolution decadal scale records of paleoenvironmental change in northwest Iceland. The assessment of both terrestrial and aquatic productivity at two lake sites in northwest Iceland will contribute to further understanding of regional paleoenvironmental shifts during the Holocene. The relationship between terrestrial and aquatic productivity at the two lake sites will also be assessed.