November 2011 Page 4

Billy Culver

Genetic Responses of a sentinel species (Daphnia) to historic pH changes in Madison Lake, Minnesota

Billy Culver

For those Friends of the University of Oklahoma Biological Station that I did not get to meet at the Friends meeting this past October, I am Billy Culver, a Ph.D. student in Dr. Larry Weider’s lab.  I am currently in my third semester at the University of Oklahoma.  Since I am doing course work on the Norman campus, I split my time between UOBS and OU Norman.  I come to OU with a varied background.  I spent six years in the US Navy as a Nuclear Electrical Technician aboard the USS South Carolina, a nuclear powered cruiser that has since been decommissioned.  While aboard the USS South Carolina, I participated in two Mediterranean Cruises, which involved both the Bosnian and Kosovo conflicts, and two drug interdiction cruises in the Gulf of Mexico.  After my service in the navy, I worked in the commercial nuclear power industry at Indian Point, New York.  While in New York I decided to return to my childhood interest in Biology.  I then enrolled and received my B.S. in Marine Biology while minoring in Oceanography at Old Dominion University (ODU) in Norfolk, Virginia.  While at ODU, I worked at the Center for Quantitative Fisheries Ecology (CQFE).  At the CQFE, I participated in population studies of several Chesapeake Bay fisheries.   After graduation, I came to the University of Oklahoma to pursue my graduate studies in Ecology and Evolutionary Biology.

In addition to working as a Research Assistant in Dr. Weider’s lab, I am pursuing my own research with regards to the genetic responses of organisms to environmental change.  In particular, I use Daphnia as my research organism.  Daphnia is an excellent organism to work with since the genome of Daphnia pulex has been fully sequenced and annotated.  Daphnia, also have the advantage of being well researched, have an asexual and sexual life cycle, have short generation times, are relatively small, and easy to maintain.  I will be studying the response of D. pulicaria to the changing pH conditions in Madison Lake, Minnesota.  Using the fact that Daphnia lay diapausing eggs that settle to the bottom of lakes and become preserved in the sediments, we have taken core samples of the lake to obtain animals that were preserved up to 40+ years ago (i.e. termed “resurrection ecology”.  The sediment will also be dated and analyzed for past pH conditions using diatom reconstruction.

Larry Weier and Billy Culver

Using a number of genetic and genomic methods, I am focusing my research on two gene families that may be involved with regulating an organism response to changing pH conditions: Carbonic Anhydrase and Chitin Synthase.  I will be isolating these genes from the animals recovered from the sediments at different time and pH periods.  Using these data, I will look to see if there is any variation in these genes and determine if they are correlated with pH change.  Experimental manipulations of animals from low and high pH conditions and treatments will be conducted.  This will allow me to determine if variation in these genes, in fact plays a role in tolerance to changing pH conditions.  From an applied perspective, this “environmental genomics” approach coupled with “resurrection ecology” should provide clues as to how aquatic organism adapt to changing environmental conditions over time periods spanning several decades, and how such changing environmental conditions can impact the quality and health of aquatic ecosystems.


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