National Save the Sea Turtle Scholarships for 2013:
Four More Graduate Students Benefit from Foundation Support
Mike Salmon
Biology Department
Florida Atlantic University
For a second consecutive year, the National Save the Sea Turtle Foundation has generously contributed four $500 scholarships to the Florida Atlantic University Foundation. These scholarships fund projects designed to advance our knowledge of marine turtle biology, conservation and management and in so doing, improve our ability to assist in the recovery of marine turtle populations. That recovery is currently in full swing and this year, green turtle nesting in the State of Florida broke new records. At the same time, both loggerhead and leatherback nesting activity has been increasing as well, though the change has been somewhat less spectacular than the numbers shown by green turtles.

What's important, however, is that nesting in Florida for all three species is definitely on the rise, and so it becomes all the more essential that we maintain those trends by learning more about sea turtle biology. That will only happen if we continue to support the training of the next generation of bright young scientists. The National Save the Sea Turtle Foundation contributes to that cause, which is all the more important because with each passing year it becomes more difficult to find support for graduate student training in biology.

This year's recipients were carefully chosen by our department's Scholarship Committee. They represent our best young scholars. After reading about their projects, I think you'll agree that they are doing interesting and important work. The four 2013 recipients are Courtney Cocilova, Jake Lasala, Karen Pankaew, and Boris Tesak. Here's what they are doing. For a second consecutive year, the National Save the Sea Turtle Foundation has generously contributed four $500 scholarships to the Florida Atlantic University Foundation. These scholarships fund projects designed to advance our knowledge of marine turtle biology, conservation and management and in so doing, improve our ability to assist in the recovery of marine turtle populations. That recovery is currently in full swing and this year, green turtle nesting in the State of Florida broke new records. At the same time, both loggerhead and leatherback nesting activity has been increasing as well, though the change has been somewhat less spectacular than the numbers shown by green turtles.

What's important, however, is that nesting in Florida for all three species is definitely on the rise, and so it becomes all the more essential that we maintain those trends by learning more about sea turtle biology. That will only happen if we continue to support the training of the next generation of bright young scientists. The National Save the Sea Turtle Foundation contributes to that cause, which is all the more important because with each passing year it becomes more difficult to find support for graduate student training in biology.

This year's recipients were carefully chosen by our department's Scholarship Committee. They represent our best young scholars. After reading about their projects, I think you'll agree that they are doing interesting and important work. The four 2013 recipients are Courtney Cocilova, Jake Lasala, Karen Pankaew, and Boris Tesak. Here's what they are doing.

For a second consecutive year, the National Save the Sea Turtle Foundation has generously contributed four $500 scholarships to the Florida Atlantic University Foundation. These scholarships fund projects designed to advance our knowledge of marine turtle biology, conservation and management and in so doing, improve our ability to assist in the recovery of marine turtle populations. That recovery is currently in full swing and this year, green turtle nesting in the State of Florida broke new records. At the same time, both loggerhead and leatherback nesting activity has been increasing as well, though the change has been somewhat less spectacular than the numbers shown by green turtles.

What's important, however, is that nesting in Florida for all three species is definitely on the rise, and so it becomes all the more essential that we maintain those trends by learning more about sea turtle biology. That will only happen if we continue to support the training of the next generation of bright young scientists. The National Save the Sea Turtle Foundation contributes to that cause, which is all the more important because with each passing year it becomes more difficult to find support for graduate student training in biology. This year's recipients were carefully chosen by our department's Scholarship Committee. They represent our best young scholars. After reading about their projects, I think you'll agree that they are doing interesting and important work. The four 2013 recipients are Courtney Cocilova, Jake Lasala, Karen Pankaew, and Boris Tesak. Here's what they are doing.
Courtney Cocilova's study focuses on the impact of red tides on sea turtles and other marine animals. Red tides occur when populations of single-celled organisms known as dinoflagellates, explode in numbers as a consequence of exposure to large concentrations of nutrients. The cells, which in some species are red in color, become so numerous and concentrated that they discolor the water making it “red”. Abnormal numbers of dinoflagellates also release large quantities of a neurotoxic substance (brevetoxin, or PbTx) into their surroundings. High concentrations of this toxin are deadly to fish, turtles, dolphins, manatees, sea birds and many marine invertebrates. A sublethal exposure to PbTx impairs their physiology and behavior through nervous system malfunction; it also suppresses their immune system, making the animals more susceptible to disease. Marine animals exposed to red tides for prolonged periods die.
Karen Pankaew is interested in marine turtle energetics, especially in the hatchlings that emerge from nests with a limited reserve of yolk energy needed for migration away from the nesting beach out to the open ocean. Between the months of July and October, Florida green turtle hatchlings emerge at night from their nests on oceanic beaches. The hatchlings crawl rapidly across the beach from their subterranean nests to the shoreline, and then swim many miles offshore to algal mats where they find food and shelter. They locate the sea from the nest by crawling away from the darker, taller dune vegetation and toward the brighter, lower oceanic horizon. However, increased beach development by humans brings with it artificial lighting, and this illumination interferes with the “seafinding” process that has gone on for millions of years. Hatchlings can be misdirected landward toward strong, localized artificial sources of light (misorientation). Another response, shown to diffuse skyglow generated by many sources of lighting from urban development, can cause hatchlings to wander for hours on the beach without direction (disorientation). Both misorientation and disorientation increase the distances hatchlings crawl, expose the turtles to predators that they would otherwise avoid, and waste valuable stores of energy. Exhausted animals may suffer from reduced survival probabilities even if they do, finally, locate the ocean. Karen is investigating the energy cost to hatchlings incurred by prolongued crawling, and how that activity affects the hatchling's swimming performance. To find out, she collects green sea turtle hatchlings as they emerge from their nests and, in a laboratory setting, places each turtle either in an aquarium or on a treadmill to measure swim and crawl behavior. Karen observes hatchling behavior during these trials noting how often each turtle rests and breathes, and how vigorously it swims or crawls. Simultaneously, she monitors oxygen consumption and collects other energy expenditure measurements. Her results will indicate whether misorientation and disorientation events consume a considerable amount of energy such that rescued turtles released immediately (the current protocol) will have insufficient reserves left to swim offshore. An alternative is to hold them in captivity for a few days and later release them by algal mats offshore. This information will help managers to decide which strategy is best for promoting hatchling survival.
Jake Lasala is interested in the mating systems of marine turtles, defined as how the sexes find and acquire mates. A few years ago, virtually nothing was known about this subject and for good reason. Marine turtles court and mate well out of sight of human observers, often in deep water some distance away from land. That being the case, few humans ever saw how the sexes interacted or had any way of learning how mates were chosen. All of that changed, however, with the invention of sophisticated underwater, battery powered video systems that could be attached to individual turtles (such as “crittercams” placed on male turtles as they pursue females). Another important discovery centered on advances in genetics that allow scientists to analyze the genetic constitution (DNA) of hatchlings, half of which is determined by their mother's and half by their father's genes. That latter approach is central to Jake's study. How do genetic measurements provide us with insights into mating systems? The answer centers around the differences that show up between the genes contributed to the hatchlings by their fathers. If females mate with a single (and one presumes, very attractive and/or very lucky) male, then all of the eggs produce hatchlings that have a limited, and repetitive, subset of a single male's DNA. However, if each female mates with two or more males, then the hatchlings from a single nest will show a varied constitution of DNA that can only come from two (or more) fathers. That situation defines a promiscuous mating system, or one in which each sex mates with several members of the opposite sex. Jake's research focuses on how many male green turtles, loggerheads and leatherbacks contribute their genes to the offspring of each female nesting on our beaches. He can also determine if the males are related and, in addition, determine for a single nesting beach just how many males are out there servicing those females! That is also a major advance since male marine turtles, unlike females that come ashore to nest, can't be easily counted. Yet, knowing their number is essential if we are to learn how marine turtle populations are changing over time. That's especially important now as the earth is warming. In marine turtles, that means more females than males may be produced (see description of Boris Tezak's research project, below). We need to know if enough males are around to service all of those females.
Boris Tezak is interested in developing new methods for accurately determining the sex of marine turtle hatchlings. Present methods require sacrificing the animal and that's obviously not the best way to obtain this information from an endangered species! In marine turtles, sex is determined by nest temperature during a critical period in embryonic development, a phenomenon known as temperature dependent sex determination (TSD). The rule is “hot babes” and “cool guys”, which means that when the eggs incubate at warm temperatures they produce mostly females, at cool temperatures mostly males, and at intermediate temperatures a mixture of males and females. In light of the rapid increase of global temperatures, a number of studies highlight the need for clear assessment of the effects of climate change on sea turtle sex ratios. However, because the mechanisms that trigger male versus female development are incompletely understood, predicting hatchling sex ratios on the basis of nest temperature result in approximations that are often inaccurate. There are more certain ways to determine sex, such as the use of laparoscopy. Laparoscopy involves the insertion of a small camera into the body cavity of the turtle to peer at the juvenile ovary of females or juvenile testes of males. Characteristics such as their size, shape, and color can be used to determine sex in somewhat older (juvenile) turtles. However, this technique has some disadvantages. First, the turtles have to be raised for several weeks to a size where these differences occur. That requires that they be housed and fed (expensive and time consuming!) Second, this procedure is unreliable for some marine turtles whose ovaries and testes develop more slowly than in other species (e.g., the leatherback). Boris' research project attempts to provide an alternative solution through the use of an entirely different approach: immunohistochemistry. This procedure is used to detect specific ovarian and testicular proteins found in a few cells taken from hatchlings. Currently, he is developing a variation of this technique to accurately identify the sex of two marine turtle species - loggerheads and leatherbacks. The development of this new technique has the potential to greatly enhance our ability to identify and investigate the effects of global climate change in sea turtle populations.

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