What kind of natural trophic variability do we see in the fish community of a large, near-pristine lake?  (When I say “trophic,” I am talking about what organisms eat.)  Scientists often use trophic changes to document other changes in lakes, such as the introduction of species or the effect of anthropogenic nitrogen loading.  But we have a limited understanding of how much background or “natural” trophic variability we might see in a lake without an anthropogenic disturbances.  And “natural” trophic variability can be hard to study because most of the lakes we use as study systems are subject to heavy anthropogenic impacts.

We used carbon and nitrogen stable isotopes to quantify spatial and temporal trophic variability in the fish community in Lake Hövsgöl in northern Mongolia.  Lake Hövsgöl is the nineteenth largest lake in the world by volume, and characterized by a low degree of human impact: it is subject to limited commercial and recreational fishing and minimal development.  We found that pelagic fish in this system demonstrated more carbon isotopic variability than did benthic fish and that spatial variability generally exceeded temporal (interannual) variability.  Interestingly, the isotopic variability we observed in this system was generally larger than that observed in comparable systems.

Publications

Young, T., O. Jensen, B. Weidel, S. Chandra. Natural trophic variability in a large, oligotrophic, near-pristine lake.  Journal of Great Lakes Research 41(2): 463-472. [pdf] [cover photo]

Presentations

American Council for Mongolian Studies, 2014 Annual Meeting, Philadelphia, PA, March 2014, Poster: “Trophic variability in a simple, pristine lake: What are the implications for studying change in other lakes?”  (T. Young, B. Weidel, S. Chandra, O. Jensen)

Ocean Sciences, 2014 Meeting, Honolulu, HI, February 2014, Poster: “Trophic variability in a simple, pristine lake: What are the implications for studying change in other lakes?”  (T. Young, B. Weidel, S. Chandra, O. Jensen)

Society for Conservation Biology, 26^th International Congress, Baltimore, MD, July 2013, Poster “Trophic variability in a simple, pristine lake: What are the implications for studying change in other lakes?”  (T. Young, B. Weidel, S. Chandra, O. Jensen)

American Fisheries Society, 142^nd Annual Meeting, St. Paul, MN, August 2012, Oral presentation: “Interannual trophic variability in a pristine north temperate lake” (T. Young, O. Jensen, B. Weidel, S. Chandra)

Ecological Society of America, 97^th Annual Meeting, Portland, OR, August 2012, Oral presentation: “Interannual trophic variability in a pristine north temperate lake” (T. Young, O. Jensen, B. Weidel, S. Chandra)

Mongolia Ecological Research Symposium, Tuckerton, NJ, February 2012, Oral presentation: “Making connections: Examining trophic relationships in a pristine Mongolian lake with high school students in Philadelphia using stable isotope analysis” (T. Young, M. Brickle, M. Clark, O. Handoko, A. Huynh, A. Nguyen, A. Nguyen, A. Lam, D. Lewis, N. Marsico, M. Muhammad, S. Small, K. Wint)