Okay, we established that turtles are important to conserve in our [last post](/jekyll/update/2015/06/24/Project-Update-0.html). As the gender of a sea turtle egg is determined by the temperature of the sand in which it is laid, known as Temperature-Dependent Sex Determination (TSD); rising global temperatures are producing more females. Some nests birth 90% female turtles, potentially skewing oceanic sea turtle sex ratios and making it possibly difficult for females to find mates as they mature (Sieg et al. 2011). Temperature monitoring is therefore critical to understanding sea turtle population movements, but current temperature sensors are limited in their capability and labor intensive in retrieving readings. Our project associate The Leatherback Trust oversees the three mile long beach of Playa Grande, where it can take a researcher up to four hours to collect a single temperature reading for each nest. As a result, biologists are only able to record temperatures once every other day, providing only a rough image of how temperatures fluctuate over the nesting season. Sensors are additionally prone to breaking, being moved or discarded by tourists, and becoming buried in the sand. Our project is to develop and test a temperature sensor that solves these previous issues while increasing measurement frequency, and then to deploy the sensors along the beach. Sensors will be dropped into the nest while the turtle is laying eggs, take hourly temperature measurements for approximately 65 days, and then be removed from the nest during the excavation biologists perform on all hatched nests. The sensor data will then be uploaded to a computer interface that automatically processes and graphs the results, allowing us to analyze information collected while in the nest and easily share that data around the world. The information will significantly enhance our understanding of the temperature variations across Playa Grande, potentially helping us better the still-unknown mechanisms behind TSD (Standora and Spotila, 1985). Additionally, temperatures we collect on nests can help us identify exceptionally hot or cold microclimates along the beach, which can be used when deciding if a nest is in significant danger of failure and needs human relocation. Improved temperature monitoring will enhance our understanding of how temperature affects general sea turtle populations. Estimates of sea turtle sex ratios at birth will become easier to predict and quantify, leading to enhanced population modeling. As sea turtles can only be sexed by killing the turtle, accurately knowing each nest temperature will allow us to noninvasively estimate the number of male and female hatchlings--saving turtle lives while increasing scientific understanding.