Turtles' Watery Woes: Pollution's Impact

Water pollution poses a significant threat to sea turtles, with human activities such as oil spills, agricultural and industrial runoff, and plastic pollution all contributing to the problem. Sea turtles are affected by various forms of pollution, including sound, thermal, photic, plastics, chemical, and effluent. The impact of these pollutants on sea turtles can vary, but they often disrupt immune systems, cause reproductive issues, and lead to changes in behaviour and difficulty eating. Additionally, plastic debris can cause physical injury and entanglement, often resulting in death. Oil spills can have severe consequences for sea turtles, accumulating in the food chain and affecting sensitive habitats such as seagrass beds, mangroves, and coral reefs. The accumulation of debris at nesting beaches can also impact female nesting activity, embryo development, and hatchling survival. With at least 11 million metric tons of plastic pollution entering the ocean each year, urgent action is needed to protect sea turtles and their habitats from the detrimental effects of water pollution.

Plastic pollution

Research has revealed that over 270 species of sea creatures, including turtles, die from ingesting plastic or becoming entangled in plastic debris every year. It is estimated that more than 1,000 turtles die every year after getting entangled in plastic, and this number is likely an underestimate. In fact, scientists have estimated that more than half of all sea turtles have eaten plastic, and in some populations, more than 90% of individual turtles have ingested microplastics.

Younger turtles and species that feed primarily on the ocean's surface generally ingest the greatest amounts of plastic. Just one piece of plastic can have a one-in-five chance of causing premature death, and turtles who ingest 14 pieces of plastic have a 50% chance of dying. The ingestion of plastic can also cause hormone-disrupting effects that feminize sea turtle populations, leading to infertility.

Plastic waste is everywhere, on the surface of the ocean, underwater, and on beaches. Sea turtles can become entangled in plastic waste, such as discarded fishing gear, while they are migrating, feeding, or nesting. Entanglement can lead to injuries, hinder their ability to swim, surface for air, or feed, and in severe cases, can lead to drowning and death.

To address this issue, individuals can reduce their consumption of single-use plastic goods, switch to reusable containers, and dispose of waste responsibly. Governments can also play a role by introducing laws and legislation banning the production or heavy taxation of single-use products and providing incentives for businesses to switch to more sustainable packaging options.

Oil spills

The potential impacts of oil spills on sea turtles are numerous and varied. One of the main dangers is that sea turtles may inhale or ingest oil, leading to toxic effects. Oil can also cover their bodies, making it difficult for them to swim and exposing them to harsh temperatures, which can cause exhaustion and make them vulnerable to predators. Additionally, oil spills can destroy important sea turtle habitats and contaminate their food sources, leading to indirect exposure to pollutants.

The complex life cycles of sea turtles, which involve migrating over long distances, make it challenging to study the specific effects of oil spills on their populations. However, researchers have estimated that thousands of juvenile and adult sea turtles were killed by the Deepwater Horizon oil spill in 2010, and many nests were also lost due to the spill and subsequent clean-up activities.

To protect sea turtles during oil spills, various response and recovery efforts are undertaken. These include rescue operations by boat, wildlife rehabilitation, monitoring beaches and coastlines for injured turtles, safeguarding nests, and conducting scientific evaluations of the spill's environmental impacts.

It is important to address the issue of oil spills and marine pollution through education, advocacy, and individual actions such as reducing oil consumption and supporting conservation organizations. By working together, we can help mitigate the harmful effects of oil spills on sea turtles and other marine life.

Chemical contamination

The impact of chemical contamination on sea turtles varies depending on the type of chemical, its concentration in the water, and the turtle's physical exposure. Pollutants can disrupt the immune systems of sea turtles, leading to difficulty eating, reproductive issues, and changes in behaviour. If pollutants enter a turtle's tissues and internal organs, they can even cause death.

The two primary sources of chemical contamination in turtle habitats are oil and other petroleum products, and agricultural and industrial runoff. Oil spills are a major problem and can have dire consequences for sea turtles, particularly in areas known as foraging grounds for the animals. Oil spills can cause skin irritation, eye damage, and respiratory problems. They also accumulate along the food chain and therefore affect sensitive habitats that sea turtles depend on, such as sea-grass beds, mangroves, and coral reefs. On a larger scale, oil from offshore spills concentrates along convergence zones, which are important areas for young sea turtle development. They may also accumulate on nesting beaches, impacting nests, nesting females, and hatchlings.

Agricultural and industrial runoff pollutes nearby water and soil habitats that turtles use. This can lead to a buildup of harmful pollutants, which can be especially dangerous for young animals. These pollutants include fertilizers, chemicals, nutrients, and untreated waste.

Heavy metals are another common pollutant that affects sea turtles. They can accumulate in the body and cause organ damage. Heavy metals have also been linked to hormone-disrupting effects that can feminize sea turtle populations and cause infertility.

Pesticides are also a significant source of chemical contamination. They can cause neurological damage and reproductive issues in sea turtles.

Noise pollution

Turtles are extremely sensitive to both light and noise. Noise pollution, therefore, drives turtles away from critical foraging and nesting habitats.

Researchers from the Woods Hole Oceanographic Institution in the US have found that turtles exposed to loud noise exhibit a sensitivity loss that can last anywhere from 20 minutes to over an hour. In some cases, hearing loss persisted for multiple days, indicating that turtles need more time to recover fully from noise exposure.

The impact of noise on turtles' hearing abilities has significant implications for their survival. Hearing is essential for communication and detecting approaching predators. With over half of turtle and tortoise species already facing threats, noise pollution is an additional stressor that needs to be addressed in conservation efforts.

To assess the hearing loss, researchers inserted a minimally invasive electrode just under the skin above a turtle's ear to monitor the electrical voltages created by the turtle's auditory system when it hears sounds. This method allowed them to determine the lower threshold of turtles' underwater hearing and which sound frequencies they heard best before exposing them to loud noise.

Light pollution

Turtles are also affected by light pollution when they are nesting. Female turtles are known to avoid brightly lit beaches, instead seeking out darker beaches with background vegetation, no artificial light, and minimal human activity. Light pollution can cause adult turtles to abandon nesting, nest in the wrong locations, or turn back to the ocean prematurely without laying eggs. It can also increase the risk of predation for adult turtles.

The impact of light pollution on turtles is made worse by the fact that no simple measure of light intensity can determine whether a light source will be a problem for turtles. In fact, the effects of artificial lighting may increase on darker, moonless nights. This means that even low levels of lighting can be detrimental.

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