Pictures of turtles entangled in six-pack rings and plastic shopping bags are among the most well-known representations of how pollution has affected our oceans and marine life. There is an undeniable impact in these photos, as the consequences of a worldwide issue become specific and familiar. And for turtles in particular, pollution affects each facet of their lives, from reproduction to migration to feeding, which lends a deeper reason for these photographs beyond their appeal and recognizability. 

A sea turtle’s life begins on the coasts, with nests being made and eggs laid on beaches and estuaries. In populated areas of the world, where shoreline pollution is high, hatchlings may encounter a piece of trash before ever setting foot in the ocean. Palm Beach, Florida, is one of the most famous places to see a new generation of sea turtles hatch and take their first dips. It is also a very popular vacation destination. Where there are people, there is pollution. The Palm Beach Town Council outlawed plastic straws and stirrers within the town in 2019, a move that indicates the severity of the issue in the area. Plastics are not the only pollutant damaging Palm Beach, other beaches in the Gulf of Mexico, and other coastal areas associated with sea turtle nesting. Rising occurrences of harmful algal blooms (HABs) and dead zones, which were covered in our May newsletter, can cut off turtles from the beaches where they nest. This is especially consequential for turtles, who often lay their eggs on the same beaches where they were born. 

Problems continue once turtles reach their habitats in the open seas or reefs. Currents and tides drag garbage out into the ocean. This has resulted in the formation of the Great Pacific Garbage Patch, an “island” of trash and plastics that is now twice the size of Texas. The Patch, located between California and Hawaii, lies in the migratory path taken by Western Pacific Leatherback turtles, who swim from Indonesia to the California coast to feed. The decline of coral reefs is among the most detrimental effects of pollution and climate change, as they support a vast number of organisms that rely on them for shelter and food. Turtles are no exception, as they are a primary habitat for hawksbill and green sea turtles. 

Turtles are uniquely vulnerable to pollution because several facets of their lives touch specific regions of the world where pollution’s repercussions are most evident. However, they are still one of millions of marine animals facing endangerment and being forced to adapt to a changing ocean. 

This spooky season we are presenting a special spotlight species that is easily recognizable as one of the most famous creatures of our oceans, the Leatherback sea turtle! Leatherbacks are unique from their turtle counterparts in a few ways. The first is that they are the largest species of sea turtle on the planet, weighing up to 1,500 pounds and 7 feet long, that’s the size of a Volkswagen Beetle! You also might be wondering how these turtles got their name–Leatherback. It comes from the distinct material of their “shell,” not made of scales like the backs of other sea turtles, but of a thick skin with a rubbery, almost leather-like texture. But why, in an underwater world of quick fins and sharp teeth, might a turtle adapt to have a softer shell? Its “leatherback” is a unique adaptation evolved over thousands of years, allowing these turtles to dive almost 4,000 feet, a depth at which the pressure is 1,800 pounds per square inch. Imagine an elephant standing on your big toe—that’s about the same pressure as 1,800 psi! This is why their shells are flexible rather than rigid, to withstand all that pressure under the sea.

Unfortunately, despite their extensive adaptations, which allow them to reach at least 50 years of age, these creatures are officially considered a critically endangered species according to the IUCN Red List. The primary reason for the decline in Leatherback population numbers comes down to the habitat loss of crucial nesting grounds. There are natural factors, such as sea level rise to blame for disappearing coastal space, but the majority of the factors are human-induced. For example, the building of sea walls impedes turtles from reaching shore, the development of coastal properties reduces nesting space, and even the artificial light on the beach and from nearby buildings can create confusion for turtles, both mothers looking to nest and hatchlings trying to navigate to the ocean. You can help by learning all about these gentle ocean giants and sharing their story with friends and family. The more people know, the more we can protect them! You can also make small changes every day—like turning off lights when you leave a room, walking or biking instead of always driving, and using reusable bottles and bags. Be a hero for the leatherback sea turtle and remember, every little action adds up to a big difference for turtles and their ocean home.

Crush and Squirt, two animated turtles from Disney’s Finding Nemo, encounter two of the main characters - Marlin and Dory - and help them catch the Eastern Australian Current. Although this may seem like a cute, heart-warming fictional scene, it is actually also accurate! 

All seven species of sea turtles demonstrate a migration pattern, or a regular, seasonal movement. Although all sea turtles migrate, the distances and areas they swim through varies based on the turtle species. Off the western coast of the United States, green sea turtles migrate a relatively “short” distance of 1,200 miles across the Hawaiian archipelago (island chain). That’s a little under the distance from the United States northern border with Canada to its southern border with Mexico! The leatherback sea turtles migrate the longest distance - traveling up to 12,000 miles round trip! Leatherback sea turtles swim from the cold Atlantic Ocean off the Canadian coast, down to the warm Caribbean ocean, and back up!

But why do these sea turtles swim such long distances, and how do they know which direction to swim? Turtles migrate primarily to return to breeding habitat and mate, find suitable nesting sites, or to return to foraging habitat. Some turtles exhibit a behavior called “natal homing” or “natal site fidelity”, in which the individuals return to the exact same beach to mate and nest every time. Turtles have several tools to help them navigate during their migration. One example are the ocean currents like the Gulf Stream or Eastern Australian Current, as demonstrated by Crush and Squirt! Scientists have discovered, however, that sea turtles also can utilize geomagnetic navigation, which relies on the Earth’s magnetic field for navigation.

Deep within the center, or “core” of the Earth, is a giant mass of moving, molten, metal at unimaginably hot temperatures. As this core moves, it generates electrical currents, which become and maintain Earth’s magnetic fields. These magnetic fields are different depending on your geographic location - where you are on the Earth’s surface. By studying juvenile sea turtle responses to simulations of magnetic fields at different parts of the globe, scientists discovered that sea turtles can sense and “read” these magnetic fields. Based on the magnetic field they are “reading”, the turtles will correct the direction they are swimming in to stay along their migration route, like having a built-in GPS!