A green sea turtle (Chelonia mydas) swimming on the coral reef at Heron Island I set out writing This Blog Is Trash to talk about the fresh and fancy life that is being a marine biologist and what my experience was as one. This was sure to include my summaries of scientific papers I was reading, detailing exploits at sea, and whatever else came to mind. In the last couple years, between juggling jobs and residences and just general chaos of the not-quite-back-to-normal-post-COVID world that we find ourselves in, I lost sight of both my blog and enthusiasm for writing. But here we are at the end of 4 long months in the Southern Hemisphere assisting the second of two friends conducting research for their PhDs and I’m here to bring back some of the classic vibes of TBIT bragging about how cool my life is. As I type this, I’m sitting on a small coral cay (sand island) at the south end of the Great Barrier Reef called Heron Island. In name, I’m here to assist my friend and peer David Adams as he conducts his doctoral research on embryonic sea turtle development. David’s research involves both lab and in-situ experiments on the effects of irrigating sea turtle nests in sand to bring down nest temperatures in the face of climate change. Me and Dave on Heron Island with his experimental plot (Turtle Deterrent Device) Sea turtles, similar to some other reptiles, have temperature determined sex ratios of their hatchlings. Warmer sand temperatures in the nest cause more females to be born, and cooler temperatures cause males to be born. With increased temperatures due to climate change, islands along the Great Barrier Reef have experienced changes in nest success and higher proportions of female sea turtles being born. This effect is exemplified by some places where nests that have hatched have had only female turtles born. So David’s research is both important and exciting because not only does his research set an important precedent for sea turtle nests in Queensland, and all over the world, but it means that as his research assistant, my job is to assist him in collecting the eggs that he needs for his experiment. But as with all field work, what I expected is not quite what I experienced. We spent the first six days on the island building and crafting and waiting out rain and watching the weather radar. I got to lift, haul, and drag lumber from the Heron Island Research Station onto the beach where we constructed David’s hatcheries. We collected sand from the beach and sifted it and baked it in drying ovens to sterilize it for his in-lab study. I got to use a sledge hammer to drive rebar stakes into the beach, feeling a bit like I was on Mythbusters out on the GBR. Experimental Plots/Turtle Deterrent Devices. Dave did a lot of excellent work, and I stood and looked pretty (as is my job) Maybe you’ve heard of a Turtle Excluder Device for fisheries, but we were building what I jokingly called Turtle Deterrent Devices, because nesting green sea turtles make an absolute mess of the beach. They dig a big pit, the likes of which would make any child on the beach proud, and then carefully dig out an egg chamber with their back flippers. The chamber is made just so, with a narrow neck and a larger base, similar in shape to a lightbulb, to lay their eggs in, and then cover with heaps of sand for the two month long incubation. Because Heron Island is the nesting place for thousands of green sea turtles and its beaches aren’t huge, there are many instances where one nesting mother will dig up the nest and/or eggs of other females. While this is a natural process, David’s research needs a constant environment, and having a nesting female bowl through all of his clutches would be pretty catastrophic for his project. And as luck would have it, a couple days after we constructed the hatcheries, a nesting female came through and plowed straight through all the work David and I had put into building the hatchery. She laid her eggs right behind the hatchery and managed to scoot right under our structure and proceeded to throw David’s sensors out from where we buried them as well as the stake we used to denote where the sensors were in the sand. She proceeded to crawl out of the enclosure, breaking our beautifully connected corner without batting a lady turtle eye. Broken Turtle Exclusion Box. "Life finds a way" - Ian Malcom We woke up the next morning and had to contend with this hurdle, and locate our missing sensors. While we were lucky that there were no clutches in that hatchery at the time of disturbance, we learned how better to keep turtles out and made some changes to the design, essentially creating a rebar fence that won’t allow adult female turtles past even if they do get the sand level low enough to pass under the wooden frames. A common thread throughout field science is thinking creatively on your feet when faced with an unexpected problem. If you are interested in reading more about David’s research, you can read the paper he published on critical oxygen requirement for embryonic sea turtle development here. Heron Island
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AuthorBree Gibbs, here. I'm a recent Master's Grad just trying to share what it's like to be a trash scientist (for those who aren't in the know, I'm a marine biologist). Categories
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