Sea Turtle Species: Pollution's Impact And Influence

Sea turtles are vulnerable to a range of pollutants at every stage of their life. From eggs to adults, sea turtles are affected by toxic metals, PCBs, petroleum products, and agricultural and industrial runoff. These pollutants can cause immediate harm through direct contact or build up in tissues over time, leading to immunosuppression and disease. Marine debris, such as plastic waste, poses a significant threat to sea turtles, who can become entangled in discarded fishing gear or ingest plastic, mistaking it for food. Oil spills and chemical runoff also contribute to water pollution, destroying the feeding habitats of sea turtles and causing tumours and other health issues. Light and noise pollution further impact sea turtles, driving them away from critical foraging and nesting habitats.

Oil spills

Inhaling and Ingesting Oil

When sea turtles surface to breathe, they can inhale oil and its vapours into their lungs. They can also swallow oil while feeding, as they may gulp oil into their mouths and throats. This can irritate the sensitive mucus membranes in their respiratory and digestive tracts and lead to negative health consequences.

Becoming Coated in Oil

Sea turtles may become coated in oil, which can impede their ability to swim and escape predators. The oil can also be absorbed into their bodies, impacting their heart and lung function and making it difficult for them to dive, feed, migrate, and mate.

Loss of Habitat and Food

Impact on Nesting and Hatchlings

Oil in the Food Chain

Impact on Health and Survival

Ingesting oil can cause large oesophageal swelling in sea turtles, displacing their liver and intestines and causing severe swelling and buoyancy problems. It can also lead to immunosuppression, making them more susceptible to diseases and increasing their vulnerability to predation and collisions with boats.

Plastics

Sea turtles often mistake plastic for jellyfish, one of their favourite foods. This mistake leads to intestinal blockages, malnutrition, reduced growth rates, and even death. Plastic bags, six-pack rings, plastic packaging, and discarded fishing gear are just a few examples of the plastic debris that entangle and trap turtles. The accumulation of plastic debris at nesting beaches also affects female nesting activity, embryo development, and hatchling survival.

Microplastics, tiny fragments of plastic less than five millimeters in size, are another concern. These microplastics are consumed by fish and other animals, which are then eaten by turtles, leading to a buildup of plastic in their guts. This can damage their ability to absorb food and nutrients, leading to malnutrition and weakening the turtles over time.

The impact of plastic pollution on sea turtles is not limited to physical entanglement or ingestion. Chemical pollutants from plastics can accumulate in the tissues of sea turtles, leading to immunosuppression and various health issues, including fibropapillomatosis disease, which causes tumors on external soft parts and internal organs.

Research has shown the severity of the plastic problem, with a recent study finding that every sampled sea turtle from the Atlantic, Pacific, and Mediterranean Seas had ingested plastic. Globally, it is estimated that approximately 50% of all sea turtles have eaten plastic, with hundreds of thousands dying each year from plastic ingestion or entanglement.

The plastic crisis in our oceans is a pressing environmental issue, with an estimated 8 million metric tons of plastic entering the ocean each year, adding to the already staggering amount of plastic pollution. If we do not take action, the health and survival of sea turtles will continue to be threatened, and the oceans that they call home will never recover.

Fertilizer runoff

Fertilizers contain minerals such as nitrogen, phosphorus, and potassium. These nutrients provide plants with the nourishment they need to grow and flourish. However, when fertilizers run off into other areas, they can have detrimental effects on the environment.

In aquatic ecosystems, the nitrogen and phosphorus in fertilizers cause algae to grow uncontrollably in what is known as an algal bloom. Algal blooms can have severe consequences, including oxygen depletion in the water, leading to the suffocation of organisms. This process can harm habitats and food resources, reduce water quality, and negatively impact the oxygen levels that fish and other aquatic life need to survive.

The impact of fertilizer runoff on sea turtles is significant. Sea turtles are vulnerable to pollution at all stages of their lives, from eggs to hatchlings to adults. Pollutants from fertilizer runoff can cause immediate harm through direct contact or build up in tissues over time, leading to immunosuppression and disease.

Additionally, sea turtles are affected by pollution through the food they eat. Small marine animals, such as plankton, absorb chemicals from the water as they feed. These chemicals accumulate in their bodies, and when larger animals like sea turtles consume them, the concentration of chemicals and pollutants increases further.

To address the issue of fertilizer runoff, it is essential to follow local codes enforcing fertilizer bans near waterways, use less chemical fertilizer, opt for natural compost, and educate the public about the impact of fertilizer runoff on marine life and the steps they can take to mitigate this issue.

Thermal and light pollution

Sea turtles are vulnerable to various types of pollution, including thermal and light pollution, which can have detrimental effects on their life cycles and habitats.

Thermal Pollution

The rise in global temperatures due to climate change has significantly impacted sea turtles' nesting beaches and habitats. Sea turtles have a unique ability to return to their hatching site decades later to nest, with the memory of the beach imprinted in their minds. However, with melting polar ice caps and rising sea levels, these nesting beaches are disappearing. The loss of ecologically productive wetlands and barrier islands directly affects sea turtles' nesting rituals.

Additionally, an increase in nesting beach temperatures influences the gender of sea turtle hatchlings. Sea turtles' eggs, being reptiles, depend on the temperature of the sand in which they are incubated to determine their gender. Eggs in the cooler parts of the nest become males, while those in the warmer parts become females. With rising nest temperatures, scientists predict an imbalance in the gender ratio, with a significant majority of the hatchlings being female. This gender imbalance poses a severe threat to the genetic diversity of sea turtle populations.

Warmer ocean temperatures also negatively impact food resources for sea turtles. Coral reefs, a crucial food source for sea turtles, are in grave danger due to rising temperatures. The "bleaching" effect caused by elevated temperatures kills parts of the coral reef. Almost half of the coral reef ecosystems in the United States are in poor or fair condition. The loss of coral reefs as a food source will have cascading effects on the sea turtles' survival and overall marine ecosystem health.

Light Pollution

Light pollution is a critical issue affecting sea turtles before they even hatch. Female sea turtles, ready to nest, seek out dark and quiet beaches. However, with increasing light pollution from coastal developments, tourism, and residential areas, nesting turtles often struggle to find suitable nesting sites. Light pollution discourages females from nesting, leading them to perform multiple false crawls. As a result, they may return to the water without nesting or lay their eggs in suboptimal locations, reducing the chances of hatchling survival.

Hatchlings also face significant challenges due to light pollution. After emerging from their nests, they typically follow the moon's reflection on the water to guide them towards the ocean. However, bright city lights disorient them, causing them to wander inland towards streetlights and buildings instead of reaching the safety of the ocean. Many hatchlings fall victim to dehydration, predation, or vehicular accidents during this journey. Millions of baby sea turtles die annually before reaching the ocean due to light pollution, according to the International Dark Sky Association.

To address light pollution, coastal communities have implemented ordinances requiring residents to turn off beachfront lights during the turtle nesting season. Additionally, the use of turtle-safe lighting, such as red lights with limited wavelengths, has proven effective in reducing disorientation among hatchlings without compromising the required site lighting.

Toxic metals

The source of these toxic metals is often anthropogenic activities, such as industrial pollution and the use of pesticides and fertilizers. Additionally, the consumption of sea turtle meat and eggs by humans has been linked to the accumulation of heavy metals in the human body, posing a risk to human health as well.

The impact of toxic metals on sea turtles is a serious conservation concern, and further research is needed to fully understand the effects of these pollutants on sea turtle populations and to develop effective strategies for mitigating their impact.

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