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Bomb Radiocarbon Dating of Hawksbill Sea Turtle Carapaces

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By: Delaney Reynolds, SRC Intern

After the 1941 attack on Pearl Harbor, Hawai’I, the United States declared martial law. In the decades that followed, the island of Kaho‘olawe, Hawai’I, an island considered sacred to Hawai’ian Natives, was used as a training ground and bombing range for the United States’ Army. Decades of bombing have not only created a threat for human health, but also any wildlife that lived in proximity to the sites. By the official end of the bombing in 2004, the army had detonated over 28,600 from the island and along the shoreline (MacDonald). One marine species that is of particular interest is the critically endangered hawksbill sea turtle (Eretmochelys imbricate).

Figure 1: This figure displays a carapace, as well as the correlation between carapace growth and number of growth marks on a scute. Van Houtan, Kyle S, et al. Time in Tortoiseshell: a Bomb Radiocarbon-Validated Chronology in Sea Turtle Scutes. Royal Society Publishing, 27 Nov. 2016.

Sea turtles’ shells are a plate-like structure comprised of “scutes” made of keratin, a component makes up human hair (Van Houtan 2016). Their shells are extremely tough and provide protection from predators. Bomb radiocarbon dating can also be used on shells to estimate growth and maturity and it is data like this that can aid in assessing population status. Hawksbill sea turtles happen to have an extremely reliable chronology when their carapace is carbon dated and can thus tell us their population status before, during, and after the bombing events on Kaho‘olawe to determine how their maturity might have changed or been effected by any radiation.

It has been found that the growth rate of sea turtles varies based on their age. As juveniles, their carapace may grow 4-5 centimeters per year. By age 10, their carapace growth declines to a rate of about 2 centimeters per year. By age 30, the carapace growth then declines to a rate of approximately 1 centimeter per year (Zug).

Figure 2: This figure displays the correlation of the percentage of Carbon-14 in the Porites (coral) cores and hawksbills’ shells to the year of core or shell formation. Van Houtan, Kyle S, et al. Time in Tortoiseshell: a Bomb Radiocarbon-Validated Chronology in Sea Turtle Scutes. Royal Society Publishing, 27 Nov. 2016.

Scientists from the national Oceanic and Atmospheric Administration (NOAA) sampled 36 hawksbills of “all life stages, several Pacific populations and spanning eight decades (Van Houtan 2016).” Growth lines were counted and referenced to Carbon-14 values from ascribed coral (Porites) cores. Annually, hawksbills create eight growth lines and it is the distance between each that can be used to estimate age.

In the 1960s, the bombing in Kaho‘olawe began to pick up and this increase can be seen in hawksbill shells’ percentage of Carbon-14 in Figure 2. At the end of the 1970s, the bombing’s demise began as Native Hawai’ian protesters risked their lives to garner the attention of their government. The bombing came to a complete halt in 1993 when Congress voted to end all military use of Kaho‘olawe and transferred the island from martial law back to the state (MacDonald 1972). This decrease in bombing can also be seen in the hawksbill shells’ percentage of Carbon-14 in Figure 2. This tells us that using the bomb radiocarbon dating of hawksbills’ carapaces is an accurate tool for aging. It was determined that wild hawksbills reach maturity between 17 and 22 years of age and captive hawksbills will reach maturity in approximately 12.3 years (Van Houtan 2016).

These bomb radiocarbon dating values also propose a decline in hawksbill trophic status. The same increase and decrease in Figure 2 appear in the coral cores. This may suggest that coral losses may lead to the degradation of sea turtle populations. It has been observed that hawksbill population size is linked to reef structure, but further study is necessary to know for sure.

Figure 3: Hawksbill Sea Turtle “Hawksbill Sea Turtle.” Wikipedia, Wikimedia Foundation, 6 Oct. 2018, en.wikipedia.org/wiki/Hawksbill_sea_turtle.

Hawksbill sea turtles were distinctively oppressed in the historic global tortoiseshell trade because their carapaces contained an abundant amount of structurally aesthetic keratin. Their shell has historically been used to craft jewelry and illegally sold (National Park Service 2017). They were listed as critically endangered by the IUCN in 1996 and placed under the protection of the Federal Endangered Species Act in 1973. In 1991, the State of Florida also passed the Marine Turtle Protection Act prohibiting the “take, possession, disturbance, mutilation, destruction, selling, transference, molestation, and harassment of marine turtles, nests or eggs (Marine Turtle Protection, Florida Fish and Wildlife Conservation Commission).” According to a 2013 report from the National Marine Fisheries Service and U.S. Fish and Wildlife Service, hawksbill populations in the United States seen both declines and recoveries in the last 20 years, but in many cases population trends were unknown.

In Hawai’i, to aid in recovery, the National Park Service has created the Hawai’i Island Hawksbill Turtle Recovery Project to monitor and protect the hawksbills and their nesting habitats found on all Hawai’ian Islands. Acting as predators to mollusks and prey to shark species, sea turtles help to keep the food web in balance and populations in check. As they are a critically endangered species and become increasingly more vulnerable to plastic pollution, consuming plastic grocery bags that resemble jellyfish for example, it is absolutely crucial for us to protect precious sea turtles and their nesting habitats.

Works Cited:

“Hawksbill Sea Turtle.” Wikipedia, Wikimedia Foundation, 6 Oct. 2018, en.wikipedia.org/wiki/Hawksbill_sea_turtle.

“Honu’ea (Hawaiian Haksbill Turtles).” National Park Service, U.S. Department of the Interior, 6 July 2017, www.nps.gov/havo/learn/nature/turtles.htm.

MacDonald, Peter. “Fixed in Time: A Brief History of Kahoolawe.” CORE, 1972.

“Marine Turtle Protection.” Laws/Regulations/Handbook, Florida Fish and Wildlife Conservation Commission, myfwc.com/wildlifehabitats/managed/sea-turtles/protection/.

National Marine Fisheries Service & U.S. Fish and Wildlife Service (2013). 5-YEAR REVIEW Hawksbill Sea Turtle/Eretmochelys imbricate, https://www.fws.gov/northflorida/seaturtles/Docs/2013_hawksbill_sea_turtle_ESA_5-year_Status_Review_FINAL.pdf

Meylan, Anne B, and Marydele Donnelly. Status Justification for Listing the Hawksbill Turtle (Eretmochelys Imbricata) as Criticallyl Endangered on the 1996 IUCN Red List of Threatened Animals. Chelonian Conservation and Biology, 1999.

Van Houtan, Kyle S, et al. Time in Tortoiseshell: a Bomb Radiocarbon-Validated Chronology in Sea Turtle Scutes. Royal Society Publishing, 27 Nov. 2016.

Zug, George R, et al. Age and Growth of Hawaiian Green Seaturtles (Chelonia Mydas): an Analysis Based on Skeletochronology. NOAA, 20 Aug. 2001.

 

Global Warming is Creating an All-Female Sea Turtle Population

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By: Konnor Payne, SRC Intern

Unbeknownst to the majority of people, sea turtles have an attribute, like many reptiles, in which the sex of the animal is determined by temperature. This characteristic is called “temperature-dependent sex determination”, which means the sex, of a sea turtle, is determined during the second trimester of incubation. Eggs at 27.7°C or below will become male sea turtles and eggs at 31°C or greater will become female sea turtles. Between these two temperatures (27.7°C and 31°C), the sex, of the sea turtle, is random (Yntema and Mrosovsky, 1982). As a consequence of this basic reproductive component, coupled with global warming increasing the temperature of the nest, a bias has formed in the sex ratios of all sea turtles towards the females (Laloë, 2016). All around the world are reports of 100% female clutches found in critical nesting sites in Barbados, Caribbean, Cyprus and the Mediterranean. The feminization of the sea turtle population has resulted in 85.9-93.5% of all sea turtles developing as females (Laloë, 2016). Projections predict that females will make up over 95% of the hawksbill population by 2045 and 2028 for leatherbacks, but green sea turtles passed this percentage in 2009 (Laloë, 2016).

Figure 1. Sea turtle eggs in an underground nest on a beach.

Although the sex is heavily skewed towards females the mating behaviors of sea turtles has prevented population issues from arising currently. Female sea turtles are not monogamous and will mate with multiple partners during a breeding season allowing fewer males necessary to fertilize all clutches (Pearce & Avise, 2001). Females can store sperm in their bodies for extended periods of time to fertilize multiple clutches at the appropriate time, reducing the frequency in which females need to contact males (Lee, 2008). The two sexes have separate breeding seasons in which the males breed more often than the females (Hays et al., 2014). These combined mating behaviors help to alleviate the problems of a biased sex population, but with the newest IPCC report indicating only increasing future global temperatures, the males will become too rare to replenish the population.

Figure 2. Female green sea turtles on a beach in Maui preparing to make a nest to lay their eggs.

Not only is there a sex bias, but global sand temperatures have begun to rise above the optimal temperature range and into the lethal zone above 32.4°C, depleting the already low populations (Moran et al., 1999). All seven species of sea turtles are classified as critically endangered, endangered or vulnerable by the International Union for the Conservation of Nature. The sand surrounding the clutch of eggs is warmed by the Sun and the atmosphere, as well as the metabolic activity of the eggs (Ackerman et al., 1985). At higher temperatures the metabolic activity of the hatchlings increases, such that the oxygen levels in the nest can decline to suffocate the hatchlings (Ackerman et al., 1985). If a hatchling does not suffocate the heat may cause thermal inhibition of muscle movement preventing them from leaving the nest (Moran et al., 1999). In the past hatchling rates were consistently above 90%, but projections show that by 2100 hatching success will gradually drop to 50.95-78.92% (Laloë, 2017). The heat from the global warming will cause causalities of sea turtles that are already struggling, which will emphasize the female dominance even more.

The future appears grim for sea turtles but there are strategies to help balance the sex ratio and lower heat stress on the hatchlings. The common problem of hatchling death and skewed sex ratio is the nest has too high of a temperature so the methods to solve both problems are to reduce the temperature of the surrounding sand. Sprinkling water at night or over a shaded area of sand consistently lowered the temperature of the sand near the nest by about 2.25°C (Jourdan, 2015). However, the source of water has to be underground via pipes or another method as an above ground source is heated in the day and causes even higher fluctuations in sand temperature than without sprinkling. The area has to be shaded by a tarp or natural cover as moist sand uncovered will increase in temperature in the day more than without water added.  The temperature of the sand decreases the deeper the nest is made, as a nest one meter lower than another is about 1°C cooler (Jourdan, 2015). Once nests are identified they can be dug up and moved deeper into the sand as the hatchlings will still be able to climb out of the nest since larger female sea turtles typically dig deeper nests than the average and have similar emergence rates (Jourdan, 2015). Most sea turtles nest during the warmest months of the year and evidence suggests that they can adapt to the warming temperatures to alter their nesting times to cooler months (Hays, 2014). Although humans have accelerated global warming, that now threatens the existence of all sea turtles, there are methods in which they can be saved.

Work Cited:

Ackerman RA, Seagrave RC, Dmi’el R, Ar A (1985) Water and heat exchange between parchment-shelled reptile eggs and their surroundings. Copeia 1985:703–711

Hays, G. C., Mazaris, A. D., & Schofield, G. (2014). Different male vs. female breeding periodicities help mitigate offspring sex ratios skews in sea turtles. Frontiers in Marine. Science, 1, 43.

Jourdan, J., and M. M. P. B. Fuentes. “Effectiveness of strategies at reducing sand temperature to mitigate potential impacts from changes in environmental temperature on sea turtle reproductive output.” Mitigation and adaptation strategies for global change 20.1 (2015): 121-133.

Juskova, Isabella. “Unsplash.com.” Unsplash.com.

Laloë, Jacques-Olivier, et al. “Climate change and temperature-linked hatchling mortality at a globally important sea turtle nesting site.” Global change biology 23.11 (2017): 4922-4931.

Laloë, Jacques-Olivier, et al. “Sand temperatures for nesting sea turtles in the Caribbean: Implications for hatchling sex ratios in the face of climate change.” Journal of Experimental Marine Biology and Ecology 474 (2016): 92-99.

Lee, P. L. M. (2008). Molecular ecology of marine turtles: new approaches and future directions. Journal of Experimental Marine Biol- ogy and Ecology, 356, 25–42.

Moran KL, Bjorndal KA, Bolten AB (1999) Effects of the thermal environment on the temporal pattern of emergence of hatchling loggerhead turtles Caretta caretta. Mar Ecol Prog Ser 189:251– 261

Pearce, D. E. & Avise, J. C. (2001). Turtle mating systems: behavior, sperm storage, and genetic paternity. Jounral of Heredity, 92, 206-211.

Yntema CL, Mrosovsky N (1982) Critical periods and pivotal temperatures for sexual differentiation in loggerhead sea turtles.

Yong, Mohamed. “Sea Turtle Egg.” Wikipedia.org, 7 Sept. 2007.

 

Buoyless Nets Reduce Sea Turtle Bycatch in Coastal Net Fisheries

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By Ryan Keller, SRC Intern

Bycatch of megafauna (larger organisms) is a serious negative side effect that stems from the practice of commercial fishing worldwide. Often fishing practices such as long lines or using nets are effective at catching the target species but also will entrap many other organisms. Often for organisms that breath air this means mortality as they may be stuck underwater for a longer period of time then they able to hold their breath.  Baja California Sur, Mexico has some of the highest recorded megafauna bycatch rates of anywhere in the world due to heavy use of bottom-set nets. Unfortunately this area also happens to be a foraging mecca for endangered loggerhead turtles.

Pictured above: An endangered loggerhead turtle swimming over a reef. Loggerheads when caught in nets cannot get to the surface to breathe leading to death.

Pictured above: An endangered loggerhead turtle swimming over a reef. Loggerheads when caught in nets cannot get to the surface to breathe leading to death. https://commons.wikimedia.org/wiki/File:Loggerhead_turtle.jpg

Between 2007-2009 Stanford University researches worked with local fisherman to compare the megafauna’ bycatch rates between traditional nets (with buoys) and bouyless nets.  Both types of nets were set near each other during the trials and the difference in bycatch recorded. The nets were checked on a regular basis to try and prevent mortality of any turtles caught in the nets. Local fisherman were compensated for setting two of the experimental nets and having a researcher with them on their trips. Later in the experiment partner fisherman were hired to fish exclusively the bouyless nets. All turtles that were caught in the nets were tagged, measured and released.  In all trials the fisherman were allowed to keep their catch and bring it to market.  The difference in the monetary value of catches between types of nets was also calculated.

As seen above: A green sea turtle (Chelonia mydas) stuck in a fishing net. Turtles often get stuck in nets that have broken free and are floating in the currents throughout the ocean, these nets are termed “Ghost nets”.

As seen above: A green sea turtle (Chelonia mydas) stuck in a fishing net. Turtles often get stuck in nets that have broken free and are floating in the currents throughout the ocean, these nets are termed “Ghost nets”. https://commons.wikimedia.org/wiki/File:Sea_turtle_entangled_in_a_ghost_net.jpg

There was found to be a 67% mean reduction in the number of turtles caught in the bouyless nets compared to traditional nets with a minimal impact on the quantity of target species. There was a decreased market value in the catch from the bouyless nets but this is most likely due to higher than average amounts of certain species being caught and brought to market at one time driving the price down. There has been other research done in this area that shows small changes such as illuminating nets at night also reduce the amount of bycatch. It is not practical to just ban the present commercial fishing methods completely. Finding ways to make small changes that have minimal impact on the fisherman and their income while drastically decreasing bycatch is the best way to gain acceptance and support from the industry. If the fisherman are minimally impacted they are much more likely to take up the new practices and not resist or revert back to prior methods.

 

Peckham, S. H., Lucero‐Romero, J., Maldonado‐Díaz, D., Rodríguez‐Sánchez, A., Senko, J., Wojakowski, M., & Gaos, A. (2015). Buoyless Nets Reduce Sea Turtle Bycatch in Coastal Net Fisheries. Conservation Letters.

Implications of climate change for the sex ratios of sea turtle hatchlings

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By Grace Roskar, SRC Intern

Sea turtles have existed on Earth for over 100 million years and presently inhabit warm waters in tropical and subtropical latitudes. The International Union for the Conservation of Nature has classified six of the seven species of sea turtles as critically endangered, endangered or vulnerable (IUCN, 2014 in Laloë et al., 2016). Threats to sea turtles include being taken as bycatch from fishing, poaching of eggs, and destruction of their habitats on land or at sea. Moreover, all sea turtle species come ashore to lay their eggs on sandy beaches, but these critical habitats face changes in air, water, and sand temperatures and rising sea levels (Santos et al., 2015). These climatic impacts occur at varying timescales and in different geographic locations, which makes it more challenging to respond to and mitigate these various threats (Fuentes and Cinner, 2010).

Like many reptiles, sea turtles possess temperature-dependent sex determination (TSD), which means that the incubation temperature of eggs in the nest determines the sex of an individual. Each species has a certain threshold, or pivotal, temperature, where equal numbers of males and females are produced. Temperatures below this pivotal temperature produce males whiles temperatures above produce females (Standora and Spotila, 1985). The determination of sex occurs in the middle third timeframe of the development of the embryo (Tapilatu and Ballamu, 2015). Due to TSD, increasing temperatures are a concern to sea turtles and were recently determined to be one of the largest threats to sea turtle populations (Fuentes and Cinner, 2010). Sex ratios could become skewed, and in more extreme cases, local extinctions could occur (Janzen, 1994 in Laloë et al., 2016). Warmer nest temperatures may lead to a greater majority of female hatchlings (Howard, Bell and Pike, 2015). Determining what ways increasing temperatures can impact populations is a priority for the conservation of sea turtles (Laloë et al., 2016).

In one study, Fuentes and Cinner (2010) used the knowledge of sea turtle experts to estimate how increasing temperatures and other climatic processes will impact sea turtles’ reproductive phases. The turtles of interest were green turtle (Chelonia mydas) populations in the northern Great Barrier Reef of Australia. Twenty-two scientists and managers were surveyed, and both groups agreed that higher sand temperatures could be considered the biggest threat to the reproductive output of these populations. The experts believe that higher sand temperatures will cause “two times more impact to sea turtles’ reproductive output than sea level rise and three times more impacts than altered cyclonic activity” (Fuentes and Cinner, 2010).

However, studies have also showed certain levels of resilience in some sea turtle populations. Howard, Bell, and Pike (2015) studied flatback sea turtles (Natator depressus) that are only native to Australia. Eggs were incubated in a laboratory to examine if the population was vulnerable to higher temperatures while nesting. The eggs were collected from beaches in northeastern Australia, and thus their pivotal temperatures were compared to those of populations from more temperate latitudes in Australia. It was found that the embryos in their study were resilient to incubation at high temperature, able to withstand temperatures almost 4°C above those from more southern populations. Moreover, the pivotal sex-determining temperature was different from past studies. It was previously thought that 29.5°C would produce an equal sex ratio, but for the eggs in this study, 30.4°C was the pivotal temperature. With a higher pivotal temperature, increasing environmental temperatures could drive the sex ratios closer towards equality. Therefore, even under extreme climate change scenarios, this high pivotal temperature adaptation may allow some flatback turtle populations to still produce more equal sex ratios (Howard, Bell, and Pike, 2015).

Not all sea turtle populations have shown such resilience. Fuentes, Hamann, and Limpus (2010) studied sand and air temperatures in the northern Great Barrier Reef. By using models and projections, it was estimated that by 2030, the sex ratios of hatchlings will be greatly skewed towards females. This has also been predicted for other nesting sites such as Cape Canaveral, Florida, and Bald Head Island, North Carolina (Hawkes et al 2007 in Fuentes, Hamann, and Limpus 2010). Laloë et al. (2016) examined historical data for incubation temperatures and sex ratios for green, hawksbill (Eretmochelys imbricata), and leatherback (Dermochelys coriacea) turtles nesting in St. Eustatius in the northeastern Caribbean. Their analysis suggested sex ratios have been skewed towards females for decades, and climate change will only intensify this. It was projected that in St. Eustatius “only 2.4% of green turtle hatchlings will be males by 2030, 1.0% by 2060, and 0.4% by 2090,” (Laloë et al., 2016). Sex ratios dominated by females have already been reported at nesting sites around the world (e.g. Barbados, Cyprus) and at certain sites, some ratios are as high as 100% female (Binckley et al., 1998 in Laloë et al., 2016).

Projections of increasing incubation temperatures at one site in St. Eustatius. Graph A shows projections for 2030, graph B shows 2060, and graph C shows 2090 (Laloë et al., 2016).

Projections of increasing incubation temperatures at one site in St. Eustatius. Graph A shows projections for 2030, graph B shows 2060, and graph C shows 2090 (Laloë et al., 2016).

Sea turtles have existed for millions of years and have previously shown the ability to adapt during periods of sea level rise and temperature changes, such as changing nesting site locations or utilizing new migratory paths (Fuentes, Hamman, and Limpus 2010). However, modern-day changes in climate have been predicted to occur at a much faster timescale than past changes. Therefore, the capabilities of sea turtles adapting to these changes are still fairly unknown (Fuentes, Hamman, and Limpus 2010). There are several management options that have been suggested in order to mitigate the effects of higher temperatures. Some active methods include artificially changing the sand temperature by sprinkling cool water on the sand, covering areas of the beach with vegetation, or creating artificial shade (Naro-Maciel et al., 1999 in Fuentes, Hamman, and Limpus 2010). Other methods include the use of hatcheries and artificial incubation where temperatures can be controlled, but there is still uncertainty about the risks associated with changing natural sex ratios. Management could also be aimed at population-wide measures, including protecting key habitats, reducing bycatch of sea turtles, and preventing illegal harvest (Fuentes and Cinner, 2010).

 

A table outlining possible management measures to reduce climate change impacts on sea turtle reproduction, provided by experts surveyed in the study by Fuentes and Cinner (2010).

A table outlining possible management measures to reduce climate change impacts on sea turtle reproduction, provided by experts surveyed in the study by Fuentes and Cinner (2010).

 

Sea turtles have key roles in the ecological function of marine ecosystems, as they help maintain seagrass beds and are a valuable part of the tourism industry for many nations. It is vital to understand how the changing environment will influence risks for current and future sea turtle populations around the world. Minimizing further anthropogenic impacts, conserving existing populations and habitats, and further investigation of sea turtles’ ability to adapt to increasing temperatures is critical to protecting these marine organisms.

 

References:

Howard, Robert, Ian Bell, and David Pike. “Tropical Flatback Turtle (Natator Depressus) Embryos Are Resilient to the Heat of Climate Change.” Journal of Experimental Biology 218 (2015): 3330-335. Web. 1 Feb. 2016.

Fuentes, M.M.P.B., and J.E. Cinner. “Using Expert Opinion to Prioritize Impacts of Climate Change on Sea Turtle’s Nesting Grounds.” Journal of Environmental Management 91 (2010): 2511-518. Web. 1 Feb. 2016.

Laloë, Jacques-Olivier, Nicole Esteban, Jessica Berkel, and Graeme Hays. “Sand Temperatures for Nesting Sea Turtles in the Caribbean: Implications for Hatchling Sex Ratios in the Face of Climate Change.” Journal of Experimental Marine Biology and Ecology 474 (2016): 92-99. Web. 1 Feb. 2016.

M.M.P.B. Fuentes, M. Hamann, and C.J. Limpus. “Past, Current and Future Thermal Profiles of Green Turtle Nesting Grounds: Implications from Climate Chang.” Journal of Experimental Marine Biology and Ecology 383 (2010): 56-54. Web. 1 Feb. 2016.

Santos, Katherine Comer, Marielle Livesey, Marianne Fish, and Armando Camago Lorences. “Climate Change Implications for the Nest Site Selection Process and Subsequent Hatching Success of a Green Turtle Population.” Original Article Mitigation and Adaptation Strategies for Global Change (2015): n. pag. Web. 1 Feb. 2016.

Standora, Edward A., and James R. Spotila. “Temperature Dependent Sex Determination in Sea Turtles.” Copeia 1985 (1985): 711-22. Web. 1 Feb. 2016.

Tapilatu, Ricardo F., and Ferdiel Ballamu. “Nest Temperatures of the Piai and Sayang Islands Green Turtle (Chelonia Mydas) Rookeries, Raja Ampat Papua, Indonesia: Implications for Hatchling Sex Ratios.” Biodiversitas 1st ser. 16 (2015): 102-07. Web. 1 Feb. 2016.

Fatal Attraction: Debris and Sea Turtles

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by Nick Perni, RJD Intern

 

For decades there has been a steady increase in the production of plastic materials. Due to negligent disposal techniques and the resiliency of the material, plastic accounts for 80% of all Marine debris in some areas. The large abundance of plastic in the world’s oceans and coastal areas has detrimental effects on marine organisms. Sea turtles in particular have been heavily affected; all six species have been recorded to ingest debris nearly 90% of which is made up of plastic. The two main ways that plastic debris affects turtles is by entanglement and ingestion. Entanglement can kill organisms by preventing it from escaping predators or drowning the animal. Ingestion can also be lethal; many animals that ingest plastics can suffer from a punctured or impacted digestive system and are also susceptible to chemicals leeching from the plastic.

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Climate change influences sea turtle nesting

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by Becca Shelton, RJD Intern

In David A Pike’s scientific paper Climate influences the global distribution of sea turtle nesting, Pike takes an in-depth look at which factors contribute to sea turtle nesting sites. There are 7 extant species of marine turtles that inhabit mainly tropical and subtropical waters and globally, are all considered to be endangered or threatened. Nesting site issues, whether they are abiotic or anthropogenic, appear to be a large contributor to sea turtle population decline. While there have been many studies on sea turtle nesting sites and conservation efforts to protect these areas, Pike’s study focuses more on the variables that attribute to the distribution of the ideal beaches for nesting and how future climate changes may affect them.

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