Once numbering in the millions, sea turtle populations have dwindled to the thousands with six of seven extant sea turtle species currently listed as endangered or threatened globally. The decrease in their once abundant populations are primarily attributed to human actions and lifestyles such as fishing practices, illegal poaching, habitat loss, climate change, and pollution. Because humans are the greatest threat to sea turtle populations, sea turtles have become a key species for conservation efforts. Conservation efforts have included monitoring sea turtle nesting beaches to help keep track of populations, introducing legislation to protect nesting females and hatchlings (such as light ordinances), studying the diseases and injuries affecting juvenile and adult populations, and employing satellite tags to track their movement to understand their behaviors.
For over 30 years, NSU has been contracted by Broward County to implement and manage the Broward County Sea Turtle Conservation Program (BCSTCP), which monitors sea turtle nesting activity on over 24 miles of Broward County beaches. More research is constantly being done to gain a better understanding of these imperiled species.
To address the gaps, former NSU marine science student Colleen completed her thesis in 2022, to better understand the microbiome of sea turtles and determine which microbes are negatively affecting healthy individuals and egg hatching success. In 2021, Colleen McMaken, partnered with the Molecular Microbiology and Genomics (MMG) laboratory of supervisor, Joe Lopez, at the Guy Harvey Oceanographic Center (GHOC) and the BCSTCP to create the most comprehensive study of bacterial impacts on sea turtle eggs to date within the continental US. Derek Burkholder and Zan Milligan also provided expertise as support as thesis committee members. This work has now been published in the journal MicrobiologyOpen as “Potential Impacts of Environmental Bacteria on the Microbiota of Loggerhead (Caretta caretta) and Green (Chelonia mydas) Sea Turtle Eggs and Their Hatching Success.” Vol 12:e1363. https://doi.org/10.1002/mbo3.1363
“Having the association between NSU and the BCSTCP provided a unique opportunity where I could be involved with the daily sea turtle monitoring and collect samples from nesting females and nests myself, while also being able to take those samples and sequence the bacterial DNA in house within the MMG,” says McMaken.
The environment is already known for impacting sea turtle nests, most notability temperature which determines the gender of the turtles. However, their research found that the environment, rather than the mother, may be playing a stronger role in influencing the microbiome of sea turtle eggs. Additionally, their research found that the abundance of certain bacteria (Pseudomonas) may influence the hatching success of the eggs themselves. Being able to identify pathogens influencing the success of sea turtle eggs and understand their transmission can help reduce threats to the conservation of these threatened and endangered species. This research is now available through MicrobiologyOpen.
McMaken graduated with her Master’s of Science in Marine Sciences in 2022 and presented this research in a talk entitled, “Microbial impacts on loggerhead (Caretta caretta) & green (Chelonia mydas) sea turtle hatching success” at the Florida Branch of the American Society for Microbiology (FLASM) meeting the same year. The funding for the research, along with her attendance to the FLASM meeting, were generously sponsored by NSU’s President’s Faculty Research and Development Grant (PFRDG). Colleen now works at the Marine Biological Laboratory in Woods Hole.
Lopez Lab @ NSU 