Pamela J. Woods will give a presentation based on the defense of her dissertation titled Ecological diversity in the polymorphic fish Arctic charr (Salvelinus alpinus) on Feb. 3. at 15:30 in Askja 131.
Pamela was born 1979 in Connecticut, USA, finishes B.A. in Marine Biology at Boston Unversity in 2001 and an M.S. in Aquatic and Fishery Sciences at the University of Washingtonin 2005. She completed a dual degree between the University of Iceland Faculty of Life and Environmental Sciences and University of Washington School of Aquatic and Fishery Sciences in December 2011. This was the first degree granted by the University of Washington as joint with a foreign university (see http://www.hi.is/frettir/fyrsti_doktorsneminn_fra_hi_og_uw ). She successfully defended the dissertation on Nov. 22 2011 in Seattle, WA, USA, with her supervisor from the University of Iceland, Dr. Sigurður S. Snorrason, her supervisor from the University of Washington, Dr. Thomas P. Quinn, and committee members Dr. Skúli Skúlason and Dr. Daniel E. Schindler.
Abstract (English below):
The Arctic charr Salvelinus alpinus is extremely diverse and its differentiation may indicate ecological speciation. This dissertation aims to compare trends in ecological diversity across broad geographical regions and place it within an ecosystem context by comparing study systems in Iceland and Alaska. In the first chapter, gut contents of Arctic charr across ~50 lakes in Iceland were analyzed to form 6 habitat-associated prey categories. Consumption of zooplankton was related to high silicon dioxide and low nutrient concentrations in the lake. Snail, tadpole shrimp, pea clam, and fish consumption were related to lake altitude, depth, and brown trout abundance. In the second chapter, the relationship between morphology and consumption within each prey category is analyzed. In the third chapter, methods are developed to detect polymorphism through the presence of multiple growth curves within populations using mixture models. Random forest models indicated that polymorphism was more likely to occur in lakes with low brown trout abundance, high altitude, and conditions with high zooplankton and fish consumption. The fourth chapter analyzes morphological variation in 4 lakes in southwestern Alaska. Two forms were found to coexist in Lower Tazimina Lake. Finally, food webs are analyzed in the fifth chapter using stable isotope ratios of fish fauna across 11 lakes in Iceland and 4 lakes in Alaska. Limnetic carbon use and piscivory appears dependent on morphological differentiation and the presence of competitors.
