d18O (LS10ANBL01a): interpretation4_scope: '' has been replaced by 'isotope'

Has 'basis' for isotopeInterpretation3 but no further information

contiguous 0.5permil1.0cm intervals; analyses, samples were washed through a 109mm mesh, and 15 Charastem encrustations were manually selected from the residue except in samples that yielded fewer stems. The encrustations were bleached in 3% NaOCl solution, rinsed four times in doubly distilled water, airdried, and ground to powder.

The dominant role of winter precipitation (Pw) in the waterbalance of Takahula Lake suggests that the lake should be particularly  sensitive to interannual changes in the strength and position  of the AL. A westerly AL corresponds to increased moisture delivery  into interior Alaska, whereas an easterly AL results in storm  systems that cross the Coastal Range and the Alaska Range and cut  off winter moisture supply to interior Alaska

These exceptionally low values suggest that factors other than effective moisture must have contributed to the pronounced variations in the Takahula Lake d18O  record. Increased winter precipitation associated with a westerly Aleutian Low position may account for 1 permil of the d18O decrease. Other factors leading to the 18O-depletion during these periods probably  include decreased temperatures, as well as increased lake-ice cover and associated reductions in evaporation.

A lowering of lake level by 0.5m would turn the lake into a topographically closed basin. Under such conditions, evaporation becomes the main  process of water loss, and lake-water continues to become 18Oenriched  until d18O of the evaporating vapor equals d18O of the input (Gat and Levy, 1978; Leng and Marshall, 2004). In contrast, a more positive water balance than the present is expected to  shorten the lake?s water-residence time, reducing the influence of evaporation on the lake?s isotope composition (Craig, 1961). Thus  the d18OCc record can be used to infer qualitative changes in  effective moisture.