Notes from one of the largest loggerhead sea turtle nesting beaches in the world
For my master’s research, I’ve spent a lot of time extracting DNA from samples collected from sea turtles in the field, but didn’t fully appreciate the process of how these samples made it to our lab’s freezer from turtle nesting beaches. To learn more, I spent two weeks with researchers at the Loggerhead Marinelife Center, in Juno Beach, Florida, who do amazing work aimed at understanding and improving sea turtle health.
Most days, I spend my time looking at nucleotide sequence data and using these data to answer questions related to sea turtle health and ecology . The huge amount of data that I, and other members of the Komoroske lab, work with is the result of countless hours spent in the laboratory processing DNA or RNA from various samples like blood or tissue. But before we can even get to the lab step, a lot of careful planning and hard work goes into collecting these biological samples. When I started my master’s degree last fall, I began working with RNA sequence data generated from green sea turtle blood samples; these samples and all of the accompanying physiological measurements had been collected by scientists working at the NOAA Southwest Fisheries Science Center. While I knew that these samples collected from an endangered species were valuable, I didn’t fully understand the work that went into obtaining them.
Recently, I spent two weeks in Juno Beach, Florida at the Loggerhead Marinelife Center working with other graduate students and scientists to get a better idea of what goes into the collection of important samples like those that I use in my own research.
Most nights during my trip were spent conducting surveys of nesting loggerhead and green turtles on a ten mile stretch of beach. The protocol for the night varied depending on the project for which we were collecting data. For one study, researchers are looking at injury prevalence in what is considered to be the largest nesting aggregation of loggerhead sea turtles in the world. For this study, we took carapace measurements, took photos of injuries, and tagged nesting females with PIT tags (a subdermal passive integrated transponder tag). For other studies, we took blood samples from the nesting females in addition to measurements and tagging. Perhaps not surprisingly, it’s pretty tricky to get blood samples from a 250 pound turtle, covered in sand, in the dark, with only a dim red light to see with!
The scientists at the Loggerhead Marinelife Center work on a wide range of projects related to sea turtle health. Recent work by both the veterinarians and research team focused on finding clinical measures to assess the status of sea turtles brought into the rehabilitation center with chronic debilitation, a serious health concern in sea turtles. I worked with another graduate student who is quantifying injury prevalence in loggerheads here; this is of particular importance in this area where high numbers of sea turtles and recreational boaters overlap, leading to greater potential for unintended boat strike injuries. These injuries can lead to infection, or result in partial loss of flippers. Not only does this impact the individual turtle, but could also reduce the fitness of the population overall if many females are injured and have difficulty swimming or digging nests to lay their many eggs.
Researchers at this facility are also using the blood samples to look for endocrine disrupting chemicals (like those found in plastics) that may interfere with normal biological function. Blood samples are also used for a metabolomics study, where scientists look at small molecules like hormones in the blood and can use this profile as a snapshot of the physiological functioning of the turtle. Even just getting tags on turtles is important—many turtles in this area have not been tagged previously, and future studies will be able to capitalize on these data to see how many turtles return to the same beach to nest, what breeding intervals are for this population, or how injuries affect survival and breeding in the long term.
It can be easy to make a plan of how to best collect samples while I’m in the lab, but actually collecting these samples and trying to avoid things like sand contamination can be far more difficult in the field. Joining all of the incredible researchers and clinical staff at the Loggerhead Marinelife Center not only provided me with the skills to work with sea turtles in a field setting, but also gave me a much deeper appreciation of the samples that have been generously contributed to my own research projects.
Jamie Adkins-Stoll is an Environmental Conservation Master’s student using genomic tools to answer several questions in Hawaiian green turtles, including quantifying breeding sex ratios, and examining immune gene diversity and gene expression profiles associated with fibropapillomatosis.
All marine turtle images taken in Florida were obtained with the approval of the U.S. Fish and Wildlife Service and the Florida Fish and Wildlife Conservation Commission under conditions not harmful to this or other turtles. Images were acquired while conducting authorized research activities pursuant to FWC MTP 205.