Carolyn A Bergstrom, Ph.D.

How does natural selection maintain phenotypic variation within marine species? What role do ecological interactions like predation and competition play? My research interests are broadly concerned with these questions. More specifically, I investigate (1) how ecological interactions in the ocean orchestrate relationships between form, function, and fitness, (2) the ecofunctional implications of bilateral asymmetries, and (3) the impact glacial melt-water has on estuarine fish communities. I explore these topics with a variety of techniques, including morphometrics and behavioral observations, field experiments, multivariate statistics, stable isotope analyses, and experimental assessment of fitness.

I currently have two main research projects underway. The first of these is the evolution of body asymmetry in flatfish. Flatfish exhibit remarkably derived body morphology. They undergo metamorphosis as pelagic larvae, where one eye migrates over the dorsal midline so that both eyes are on the same side of the head, and they lie on the ocean floor, eyed-side facing up. While the vast majority of the 715 flatfish species contain all left-eyed or all right-eyed individuals, 7 species contain both morphs. To date, we don't have a good understanding of the evolutionary trajectory flatfish took to become asymmetric, or the significance of asymmetry direction. One polymorphic species, the starry flounder, exhibits a cline in the north Pacific in the relative frequency of left- vs. right-eyed individuals, and the two morphs show evidence of ecological segregation. It is one of the first demonstrations of the ecological significance of polymorphism in a marine species, and contributes to our understanding how asymmetry evolved across the flatfish order. 

My second current research project involves how glacial melt water affects fish living in estuaries. Glacial estuaries differ in habitat characteristics from rain-fed estuaries, including temperature, sediment composition, turbidity, and water chemistry. In a collaborative project funded by EPSCoR Alaska and Alaska Sea Grant, we are comparing community structure of fishes found across estuaries that differ in their glacial influence. Differences in these communities will inform predictions of how marine fishes will respond to predicted increases in melting rate of glaciers that flow into our oceans.