ALBERT

Beschreibung:    High-latitude ecosystems are among the most vulnerable to long-term climate change, yet continuous, multidecadal indicators by which to gauge effects on biology are scarce, especially in freshwater environments. To address this issue, dendrochronology (tree-ring analysis) techniques were applied to growth-increment widths in otoliths from lake trout ( Salvelinus namaycush ) from the Chandler Lake system, Alaska (68.23°N, 152.70°W). All otoliths were collected in 1987 and exhibited highly synchronous patterns in growth-increment width. Increments were dated, the widths were measured, and age-related growth declines were removed using standard dendrochronology techniques. The detrended time series were averaged to generate an annually resolved chronology, which continuously spanned 1964–1984. The chronology positively and linearly correlated with August air temperature over the 22-year interval ( p  〈 0.01), indicating that warmer summers were beneficial for growth, perhaps by increasing fish metabolic rate or lake productivity. Given the broad distribution of lake trout within North America, this study suggests that otolith chronologies could be used to examine responses between freshwater ecosystems and environmental variability across a range of temporal and spatial scales. Content Type Journal Article Category Original Paper Pages 1-7 DOI 10.1007/s00300-012-1245-9 Authors B. A. Black, Marine Science Institute, University of Texas at Austin, 750 Channel View Drive, Port Aransas, TX 78373, USA V. R. von Biela, U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, AK 99508, USA C. E. Zimmerman, U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, AK 99508, USA R. J. Brown, U.S. Fish and Wildlife Service, 101 12th Avenue, Fairbanks, AK 99701, USA Journal Polar Biology Online ISSN 1432-2056 Print ISSN 0722-4060