Sea Turtle Bicephaly
Blog Post By: Ashlyn, Sea Turtle Intern
Before you ask—no, I wasn’t scheduled for dawn patrol that morning. And by that morning, I think you know that I am talking about the morning that a hatchling loggerhead sea turtle with two heads was discovered here at Edisto Beach State Park. Ask the rest of the turtle team—Leah, Chase, or Karoline—who were all on patrol that morning, about their firsthand account. All I know is that my alarm clock that early morning was a stream of text messages of pictures of this turtle marvel, rather than my typical ringing sound.
At first glance of those pictures that flooded my message inbox that morning, my mind sparked with curiosity at this turtle anomaly. How often does the presence of two heads in a single individual occur? Is this common among reptile hatchlings?
The head is one of the most complex structures of the body, derived from three primary dermal layers and specialized neural crest cells. The development of the head region of the body during embryogenesis is quite complex, involving hundreds of genes interacting to regulation the proliferation, migration, and differentiation of cells. Within all of these regulatory processes, there is susceptibility to dysregulation, as is to be suspected.
In fact, the highest reported mutations in green, loggerhead and, olive ridley sea turtles are craniofacial malformations. The development of brain, cranium, and facial region are interconnected and complex, as the signaling pathways during development have extremely complex regulators and growth factors.
Among marine reptiles, sea turtles in particular have a history of reported bicephaly, or the presence of two heads in a single individual. Bicephaly is an umbrella term, describing developmental alterations such as the duplication of head structures, incomplete splitting of zygotes (conjoined twins), or terminal bifucation of the notochord while neurulation is taking place. Research suggests that sea turtles with this condition have an extremely short life expectancy, only hours or days. The rarity of observing this phenomenon has limited our scientific understanding of potential causes of the presence of two heads. It is believed, however, that a combination of genetic, environmental, and developmental causes may all play a role.
More research regarding bicephaly in reptiles has been focused on snakes, as the most reported malformation in wild and captive snakes is indeed the presence of two heads. While still a relatively new direction in the field, preliminary research suggests incubation temperatures, inbreeding depression, hybridization, chemical toxins, and environmental pollution all are associated with snake bicephaly.
In short, no—no I did not witness the two headed turtle that has been circulating the news this week firsthand. But yes—yes I did marvel and research and marvel yet again at the wonderful anomaly that crawled on our beach.
We are in our final week of night walks for this season! We were a little wary about our walk portion of the night walk as a thunderstorm was in Beaufort and it appeared it may decide to make its way towards Edisto. We kept an eye on the weather as we started the walk with the hopes of seeing a turtle before any lightning drove us off the beach. We made our way towards the inlet and then turned around without a sighting yet. It did appear a few nests had already had hatchlings emerge prior to our walk.
On the way back to the WIFI room, a turtle was spotted emerging from the ocean. Unfortunately, lightning had become too close to stay out on the beach, so we quietly passed by the turtle and took a detour through the campground.
The following morning our dawn patrol team found three new nests and five nests that had signs of emergence! The turtle we saw was nest 196 on our state park beach. See below for a few more photos.
Night Walk 7/22 - No turtles seen!
We had a wonderful night walk on Saturday, with the hopes of seeing a nest emerge or a turtle come ashore to nest! Unfortunately, we did not get to see any turtle activity during our program. There had been a couple nests that had already emerged prior to us walking. It is always a guessing game as to when they will decide to make their mad dash to the ocean. The following morning there were no new nests or false crawls but the interns and volunteers found that 5 nests emerged!
We had an exciting start to our night walk program on Thursday! One of the nests showed possible signs of emergence, so we brought the night walk group onto the beach as soon as they arrived. We did not have to wait too long and the sand started to "boil" with emerging hatchlings. They successfully made their way across the beach and into the ocean as we cheered them on.
After the hatchlings successfully made it into the water, we went back to the WIFI room for the presentation. Following the presentation, we proceeded to walk the beach in the hopes of seeing a nesting adult sea turtle. Unfortunately no other turtle activity was found but it was a beautiful walk under a bright moon!
The following morning our turtle patrol found that three nests showed signs of emergence and no adult tracks or nests were found!
Night Walk 7/20 - A Turtle Seen
We had an adventurous night walk on Tuesday with a downpour on the walk back to the office and one turtle seen! On our way back from the inlet, Ashlyn came across some campers who witnessed an emerging turtle. The campers did the right thing by keeping a distance and staying still in the dark. Unfortunately this turtle did not find a place to nest and ended up completing a false crawl. The night walk group got to witness her as she went back into the ocean. She had an old injury to her carapace and her rear flipper, so perhaps that was part of her problem in successfully nesting.
The following morning we found 1 new nest and 1 false crawl. We also completed an inventory and found the most unusual find of all, a two-headed hatchling! See below for pictures taken during the patrol.
Blog Post By: Chase, Sea Turtle Intern
Our sea turtles’ threats are mostly easy to spot - raccoons, beach erosion, and artificial lights, just to name a few, can all be simply observed by anyone. One of the most dangerous threats affecting the future of our sea turtles, however, is one that we find a little bit harder to spot on a walk down our beach: Earth’s changing climate.
The Earth’s climate is changing - that’s a fact. Regardless of how it is happening, however, we have to adapt to it, and so do our sea turtles. As much fun as some warm weather sounds for our cold-blooded friends, the coming changes are especially challenging for our marine life.
Rising temperatures pose a threat for our sea turtles before they are even born. As you may know, sea turtles’ sex is determined by their temperature as the eggs reach about ¾ of the way through incubation. Warmer temperatures produce females, and cooler temperatures produce males (“hot chicks and cool dudes,” if you will). Even though we only ever see nesting females, male sea turtles are still very integral to keeping up with sea turtle populations. So, as temperatures rise and nests warm up, more females will be produced than males. In nesting areas like Florida and Australia, scientists are finding that hatchlings are overwhelmingly female, up to 99% of hatchlings on some beaches.
Without males, even further population decline is inevitable.
Almost more alarming is that for some beaches, nests are getting so much hotter that hatchlings just don’t hatch. Although an overly-female population is alarming, the annual decline in hatch rates is an immediate threat. Published estimates have found that populations will continue to decline by about seven percent per year due to rising temperatures. Boca Raton’s nests used to have an average hatch rate of 78-81 percent, until 2015, when temperatures increased further and hatch rate dropped to 54 percent. In 2016, that hatch rate dropped further to 42 percent.
Increases in temperature mean a lot more than just warmer air, though. Carbon dioxide, one of the “greenhouse gases” contributing to climate change, is naturally absorbed from the atmosphere into the oceans. Climate change is the main cause of coral reef destruction all over the world, and the coral bleaching associated with rising CO2 levels in the main cause of death. Coral reefs serve not only as habitats for many species of sea turtles, but also as ecosystems for their food to grow. Reefs serve global coastlines as well by slowing waves and protecting them from erosion, ensuring that sea turtles’ nesting habitats stay in place.
Along with our coral reefs, coastlines are disappearing at faster-than-normal rates. As the oceans rise, good nesting ground for our sea turtles is covered in water. As well as covering the coasts, rising oceans also pull more sand and sediment away, eroding the beachfront faster than before. Climate change has also very likely increased the severity of tropical cyclones in recent years, helping to further wash away our beaches, and taking sea turtles’ nesting zones with them.
No matter how you want to see it, things are changing. Our turtles are in trouble, too, and we are trying to adapt to help them. Turtle teams in Florida are testing shading and water-cooling methods for nests to combat the effects of rising temperatures on sea turtle eggs. Scientists are working on breeding corals that can resist bleaching and heating in order to survive and grow. Many hope to counteract the side effects of climate change while its roots are being addressed, to give nature time to adapt.
A global problem requires a global solution, and everyone’s effort adds together. Our sea turtles need our help, and we’re doing everything we can. Just understanding the problem is a great beginning to solving it.
Night Walk 7/17 - A SUCCESS!
Blog Post By: Karoline, Sea Turtle Intern
While on my way to set up for the night walk on Saturday, I received a call from Leah saying that if we hurried, we could potentially catch a boil on the beach! A boil is when the hatchlings emerge from the nest, something that I had never seen until last night. Haley (an Environmental Learning Center intern and sea turtle volunteer) and I put the pedal to the medal, parked the car, and sprinted to the beach. We were expecting to immediately have the hatchlings emerge, but as we know, turtles work on turtle time, so of course that didn’t happen. We arrived at the scene breathless, only to have to sit and wait for 45 minutes. The good thing about the wait, however, was it gave our night walk participants time to arrive and see the hatchlings! Once the little hatchling at the top who I nicknamed the “scout” hatchling seemed to give the “all clear” to the rest of the nest, they all came up and easily made their way to the water. Our night walk participants did a great job and let the hatchlings do their thing!
All summer I have been waiting and hoping to see a boil. I’ve even come and looked for hatchlings on my night off! Knowing how our turtles are, I’m sure they thought it would be funny to take their time and hatch right at the start of a night walk After an exciting start to the walk, we came back to the Wi-Fi room for the presentation. We finished up with some great questions from the group, and then headed out to the beach. This was my first night going out ahead of the group looking for turtles and hatchlings, and I was very excited. I checked all the nests on my way up the beach, while still looking for adult turtle tracks. Finally, when I got to mile marker 0.8 there was an awesome person walking the beach who showed me that there was a turtle in the dunes! I slowly crept up and found that she was laying! The group approached, and we saw a beautiful big turtle lay nest number 185. After she finished, she made her way down to the water and we said our goodbyes. Then, on the way back to the white office building, I saw another track, and lo and behold there was another turtle laying right by the white building! This nest was number 183. I kept an eye on her as the night walk group left, as it was already becoming a late night. It was an awesome “circle of life” night walk with some fantastic night walk survivors!
Night Walk 7/15 - A SUCCESS!
On our way to the inlet we spotted turtle tracks but unfortunately she had already turned around and left, creating a false crawl. Walking down just a bit further, we got word that the turtle had already come ashore and then left, leaving a new nest behind. On our way back from the inlet, another track was seen but this time it was just one incoming track. Ashlyn spotted the turtle, still creating her body pit. We patiently waited as she dug her egg chamber before getting a closer look. This turtle situated herself underneath the light screen of nest 10! So while she was nesting, we pulled up some of the light screen stakes. Then while she was covering, she was being extra feisty and was breaking the stakes of nest 10! We got to watch her return to the ocean after successfully laying her eggs.
The following morning we found three new nests, 2 false crawls and another nest hatched. The nest we saw during our night walk program is marked as nest 179 on our beach. See below for pictures taken from the morning patrol.
Night Walk 7/13 - No Turtle Seen
The turtles evaded us yet again as we returned from the inlet without a sighting. We still had a fun night walk! We got startled by scurrying ghost crabs, discussed horseshoe crabs, checked out constellations and looked for bioluminescence before a wave soaked all of us!
The following morning they found two new nests and one nest that had emerged! We are now up to 174 nests on the state park beach. See below for pictures taken during the dawn patrol.
Understanding Loggerhead Population Demographics: the “Why” behind Genetic Studies
Blog Post By: Ashlyn, Sea Turtle Intern
Setting the scene: On every beach spanning the Atlantic Coast from North Carolina to Florida, night patrollers would be walking the beach from dusk until dawn, attempting to encounter every nesting loggerhead that emerges from the ocean to nest along the dunes. Tags must be given to each turtle encountered with thorough documentation occurring throughout the night, and fingers must be crossed that no turtles evade the nightly patrol. A logistical catastrophe.
Tagging studies on nesting beaches, the historical common practice to estimate nesting frequencies among other population demographic parameters, cannot obtain the magnitude of samples required for confident determination of sea turtle population demographics. Therefore, Dr. Brain Shamblin and his team at University of Georgia, altered the precedent. Since 2010, the Edisto Beach State Park beach along with beaches all along the Southeastern Coastline have participated in Dr. Shamblin’s genetic study of loggerhead sea turtles, allowing for a deeper understanding of loggerhead nesting population demographics, furthering sea turtle conservation efforts.
Rather than a focus on directly on the mother turtle, focus shifts to the eggs to obtain information about the mother. From each nest discovered on the beach, a single egg is obtained from the clutch within 15 hours of oviposition. In its entirety, the egg contains both the mother’s and father’s genetic material; however, the shell of the egg contains genetic information solely from the mother. For this reason, the yolk contents of the egg are sacrificed, and the shell of the egg is preserved in a 70% ethanol solution to allow for the isolation of DNA from the eggshell of the mother loggerhead sea turtle. Genotypes are derived from a single-locus from the unincubated egg shell, with an accuracy rate of 97.6% to the genotype that would have been derived if taken directly from a skin sample of the mother loggerhead.
The development of this single locus genotype frequenting technique serves as a groundbreaking noninvasive method in furthering our understanding of sea turtle population demographics. This methodology additionally is applicable to other marine turtle populations in which direct interception of the nesting female is logistically not feasible when genetics studies are being conducted.
For more information regarding the nesting patterns of loggerheads on the EBSP beach, visit www.seaturtle.org for maps and data information. For more information regarding the genetic extraction process within the laboratory, visit the website of Dr. Brain Shamblin for links to his published works.
Night Walk 7/10 - No Turtle Seen
We had a walk to the inlet under a starry sky with plenty of shooting stars! Unfortunately our wishes to see a nesting turtle did not come to fruition, as we returned back to the office without seeing a turtle. There were plenty of fun things to check out along the way including bioluminescence, ghost crabs, fossils and a black-tipped shark.
The next morning our dawn patrol team found 4 new nests and 3 false crawls! These turtles must have come ashore to nest within the hours of 12am and 6am as they evaded us on our walk. We are excited to be up to 164 nests now on our beach! Check out the pictures below taken from our patrol team.
The Case of the Exposed Eggs
Blog Post By: Karoline, Sea Turtle Intern
On June 23 around 2 pm, Leah received a call from a worried beach goer about some turtle eggs that were exposed on the scarp at the inlet. After asking for some more information before going to check it out, she received a video of the nest, and sure enough there were exposed eggs! Turtle patrol is always ready for action, so we jumped in the turtle cart and headed to the scene of the crime. But, after a once over of the inlet, there were no eggs to be found…
Feeling confused, we looked again more closely, and this time found some tiny little white ovals exposed on the scarp. We then realized that the perspective on the video had made the eggs look like they could be sea turtle size (which are about ping pong ball size), but in reality the eggs were much too small to be from a sea turtle. After our revelation that these were not sea turtle eggs, we came to the conclusion that they must be eggs laid by a diamondback terrapin! Diamondback terrapin eggs are oval shaped, pinkish-white, leathery, and about 1 inch long. Though the eggs weren’t laid by a sea turtle, Turtle Patrol is always ready to help a turtle nest in need, and these eggs had to be moved out of the sun ASAP! So, we grabbed our relocation bucket and got to work. This was definitely the quickest relocation I have ever been a part of, since female diamondback terrapins are about nine inches long, compared to our female loggerheads that are about three feet long. Diamondback terrapins nest May through early July at night, similar to our sea turtles that nest May-August at night. Sea turtle nests are about 18-24 inches deep, so it was light work for us to dig a new diamondback terrapin nest in a more secure spot in the dunes with a depth of 4-8 inches. A typical diamondback terrapin nest will also have about 4-8 eggs in a clutch, whereas our loggerhead sea turtles have about 120 eggs per nest. Our nest in need of a relocation had 8! After moving the eggs, we cut up a small section of our sea turtle screens and used some sticks as posts to hold the screen. We then put some orange tape around our little nest and bid it farewell!
Typical egg incubation for diamondback terrapins is about 60-85 days, depending on soil temperature and nest depth. Loggerhead incubation is a bit shorter, about 45-60 days. So, in a couple months or so, we will hopefully have some healthy diamondback terrapin hatchlings make their way from their beautiful new nest to some brackish creeks! If there was to be a prolonged cold snap within the next 60-85 days, however, the hatchlings may decide to “overwinter” in the sand and hatch next spring!
Like our loggerheads, females can lay several clutches during one breeding season, so let’s hope this diamondback terrapin’s next nest is in a better location! We loved working on this nest and can’t wait to see the results of our miniature relocation. Thank you to the person who reported it to us!
Night Walk 7/8 - A SUCCESS
We had another successful night walk on Thursday! On our way to the inlet we got to witness a very large turtle head back into the ocean after completing a false crawl. On our way back to the WIFI room, we had another turtle ashore! She crawled to a very high scarp so we were unsure if she would be able to get above it. There was another turtle further down that just finished laying her eggs, so we quietly passed by the one turtle to witness the successful nester cover and return to the ocean.
The one false crawl had suspicious tracks that almost looked parallel, as if a green turtle was the one responsible! I have sent the photos to DNR for confirmation. I believe it is still a loggerhead but it would be neat if it was a green wanting to nest on our beach. Hopefully this turtle will return to nest successfully!
The following morning we found 1 new nest and 2 false crawls. The nest we saw during our night walk is marked as nest 158 on our beach! See below for pictures taken during the morning patrol.
Night Walk 7/6 - A SUCCESS!
We had an eventful night walk on Tuesday! As soon as we started to walk, I noticed a dark form crawling out of the ocean between myself and our night walk group! We had a turtle emerging. We thought this may be the shortest night walk to date but unfortunately she decided it was not the spot for her. We got to watch her once she was crawling back into the ocean.
Further down the beach, tracks were seen but the turtles had already come and gone, also completing false crawls. Continuing our trek towards the ocean, another crawl was seen but this time there was only one incoming track. We waited and waited and waited while this turtle was completing her egg chamber. We wondered why it was taking her so long. Finally once she was laying we were able to see that she was missing part of her rear left flipper! No wonder she had a harder time digging. We watched as she covered her eggs and then returned to the ocean.
The following morning, our patrol team marked this nest as 153! This nest was situated too close to the scarp and below the Spring high tide line so a relocation was needed. They carefully moved her 101 eggs to a safer location. In total, our patrol team found 2 new nests and 7 false crawls.
Night Walk 7/3 - A SUCCESS!
We had a successful program on Saturday night! On our way to the inlet we spotted one turtle and watched her as she crawled into the ocean. Unfortunately this turtle did not nest and was returning after completing a false crawl. On our way back from the inlet, more turtle tracks were spotted near the campground! This time the turtle was ashore and was laying eggs! We got to witness her lay her eggs, cover and then return to the ocean. On our way back there was another emerging turtle! To make sure we did not disturb her, we took a detour through the campground to get back to the WIFI room.
The following morning, our dawn patrol team found 5 new nests and 3 false crawls. The nest we saw during our night walk program is marked as nest 146 on our beach.
I apologize for the later blog post but this past weekend was a busy one at the park! I hope everyone had a great July 4th weekend!
Blog Post By: Chase, Sea Turtle Intern
When I tell people I’m an “environmental geoscientist'', they typically look at me kind of puzzled - what does the rock guy have to do with turtles?
Well, surprisingly enough: a lot.
To start, geoscience is a much broader study than geology. Geoscience is an expansion; it is not just the rocks and erosion of geology, but also climate, habitats, food webs, water resources, and the interactions between Earth’s many systems in order to sustain life.
Geoscience is green. It is the study of the ways things connect and web together. It is also rocks and sediments and oceans, but as a geoscientist, I focus on how those rocks, sediments, and oceans interact together to create an ecosystem.
Most importantly, geoscientists focus on the intersections of what we call Earth’s Four Systems: the hydrosphere (the Earth’s water resources), biosphere (everything that lives), atmosphere (climate, weather, and other air-related processes), and lithosphere (rocks and plates). Geoscience is the study of the Earth, meaning that geoscientists must fully understand the ways that the many systems interact with one another, and the results of those interactions.
For example, loggerhead sea turtles, part of the biosphere, live in the ocean, part of the hydrosphere, then nest on our beach, part of the lithosphere, in the right climate, part of the atmosphere. Whereas a geologist might observe the sand, or a climatologist might observe the temperature of the nests, a geoscientist looks at the way that the sand affects the temperature of the nest, which then affects the hatchlings, who, as a keystone species, affect the quality of Earth’s water systems.
To simplify things, geoscientists study the Earth as a big picture - how one thing affects another, and how the planet relies on those interconnections in order to survive.
For our sea turtles, geoscience plays many roles. Geoscientists can provide insight into the way that the beach erodes and changes, creating and altering sea turtles’ nesting. They observe the turtles’ predators, like ghost crabs and racoons, noting how the effects of the predation not just on sea turtles but also on the predators’ populations. They monitor how storms affect the beachfront and how they inhibit nesting sea turtles.
I research the ways that our planet and its changing face affect our turtles, and vice-versa.
Geoscience, although bearing the same prefix as geology, has a different focus than other branches of study. Geoscience is Earth Science. It is the study of Earth’s fickle connections, and the way that life itself interacts with the planet. It is the branch between biology and geology - the science connecting life to earth.
Night Walk 7/1 - A SUCCESS
We had a long walk and a late night walk but it was filled with turtle encounters! We witnessed the first turtle returning to the ocean after false crawling. Then this same turtle that later got the nickname "shark bite" due to the large chunk missing from her left rear carapace, tried crawling ashore again. We witnessed her from a distance false crawl for the second time. We are not sure why she was completing false crawls as there was no disturbance to her, I guess she was just looking for that right spot!
Then as we walked down the beach a little further, we witnessed a turtle returning to the ocean after successfully completing a nest! This nest had to be relocated in the morning as she nested below the Spring high tide line.
After reaching the inlet, no other turtles were seen nesting but on the way back we got to see a nesting turtle! At this point, it was past midnight and we were all feeling pretty sleepy and tired but we powered through with the excitement of a nesting turtle. We watched as she laid her eggs, covered and then returned to the ocean.
In the morning, we had 4 new nests and 4 false crawls. The nest we saw is marked as nest 140 on our beach. See below for more pictures taken from the dawn patrol team!
Sea Turtle Biologist