Sea Turtle Crisis: Impact Of Pollution On Their Lives

Sea turtles are vulnerable to pollution at every stage of their lives. Plastic pollution is a significant threat to sea turtles, as they can easily mistake plastic for food, such as jellyfish, and ingest it. This leads to intestinal blockages, malnutrition, and even death. Additionally, sea turtles can become entangled in plastic debris, such as fishing nets and six-pack rings, causing injuries and drowning. Research suggests that a single piece of ingested plastic can increase a turtle's chance of dying by 22%. Other forms of pollution, such as oil spills and chemical runoff, also have detrimental effects on sea turtles, contaminating their habitats and causing diseases. With all species of sea turtles affected by marine pollution, it is crucial to address this issue through education, waste reduction, and conservation efforts.

Plastic ingestion

Sea turtles ingest plastic in various ways and at different stages of their lives. The primary cause of plastic ingestion is the resemblance of plastic items to the turtles' natural food sources. For example, sea turtles often mistake plastic bags for jellyfish, one of their favourite foods. Similarly, they may confuse plastic debris such as fishing nets for seaweed or other edible plants. The scent of marine plastics, which comes from the organisms that attach themselves to the plastic, also attracts sea turtles, making them more likely to ingest plastic waste.

The ingestion of plastic has severe consequences for sea turtles. It can cause physical damage to their intestines, lead to intestinal blockages, and even pierce the intestinal wall, resulting in internal bleeding. Blockages can be fatal, and even if the turtles survive, the blockage can leave them feeling unnaturally full, causing them to neglect their food intake and eventually starve. Additionally, the ingested plastic can make turtles unnaturally buoyant, hindering their growth and reproduction rates. According to research, a single piece of plastic can be fatal for a turtle, with a 22% chance of causing death.

All species of sea turtles are at risk of ingesting plastic, and it is estimated that more than half of all sea turtles have consumed plastic. The carnivorous loggerhead and the herbivorous green turtle are particularly vulnerable, with studies indicating that they ingest plastic at alarming rates. Loggerhead turtles, for instance, ate plastic in 17% of their encounters, likely mistaking it for jellyfish. This number soared to 62% for green turtles, which are primarily in search of algae.

The impact of plastic ingestion on sea turtles is not limited to physical harm. When baby turtles crawl towards the ocean, they must navigate through plastic debris, increasing the likelihood of ingestion at a very early stage of life. Additionally, plastic waste can accumulate in nesting areas, hindering the movement of adult turtles as they return to the ocean and putting baby turtles at risk of entanglement and ingestion.

The accumulation of plastic waste in the oceans poses a significant threat to sea turtles, and the convergence of plastic and young sea turtles in ocean currents further exacerbates the problem. While efforts are being made to address plastic pollution, it is crucial to continue reducing, reusing, and recycling plastics to protect sea turtles and other marine life.

Oil spills

Sea turtles are highly vulnerable to oil spills at every stage of their life. Oil spills can affect their habitats, their food sources, and their health.

Once inside their systems, oil can impede breathing and heart function, making diving, feeding, migrating, and escaping predators more difficult. Sea turtles coated in oil are at risk of exhaustion and dehydration. In addition, dark oil under a hot sun can heat up turtles to dangerous temperatures, jeopardizing their health and even killing them.

Fertilizer and chemical runoff

Runoff from fertilizers and chemicals can also contaminate the food that sea turtles eat. Small marine animals, such as plankton, absorb these chemicals as they feed, and the chemicals accumulate in their bodies. These small animals are then consumed by larger animals, like sea turtles, which further increases the concentration of chemicals and pollutants in their systems.

In addition, some toxins become more concentrated as they break down and enter the food chain. For example, nitrogen converts to nitrate in water, which can cause health issues for humans and aquatic life. Nitrate in drinking water has been linked to increased health risks for humans, and in the ocean, it hyper-charges the growth of aquatic bacteria and algae, depleting the water's oxygen and making it uninhabitable for many sea creatures.

Another consequence of fertilizer and chemical runoff is biodiversity loss. As time passes, an algal bloom in a lake or stream chokes out other species, and the altered balance of species has significant impacts on the food chain and larger ecosystem. A shortage of fish may drive away mid-chain consumers and even apex predators, as they search for a more reliable food supply.

Finally, fertilizer and chemical runoff can contribute to ocean acidification. While climate change is a significant factor in ocean acidification, eutrophication associated with runoff also plays a role and compounds its harmful effects.

Marine debris entanglement

Hatchlings, in their initial journey towards the ocean, often have to crawl through plastic and other debris, which can entangle and trap them. As they grow and start their migrations, they encounter vast areas of ocean plastic, discarded fishing gear, and even six-pack rings, which pose a significant entanglement risk. The problem is exacerbated by the fact that sea turtles can mistake plastic bags and mylar balloons for their favourite food, jellyfish, leading to ingestion and entanglement issues.

The consequences of entanglement can be dire. Air-breathing sea turtles, such as the green sea turtle, can drown if entangled as they are unable to swim to the surface for air. Smaller turtles may also drown immediately if trapped under heavy or large debris. Even if they manage to survive the initial entanglement, the gear can cut into their flesh, causing physical trauma and infections. Restricted by the gear, they may starve or be unable to avoid vessels, increasing the risk of vessel strikes.

The impact of marine debris entanglement on sea turtles is not limited to a single species. At least 115 marine species worldwide are affected by entanglement, and sea turtles are among the most frequently reported affected species. This issue is not merely an animal welfare concern but also has ecological implications, as it disrupts the natural balance of marine ecosystems.

To address this issue, it is crucial to minimise the amount of marine debris entering the ocean. This can be achieved through community clean-up efforts, proper waste management, and reducing the use of single-use plastics. Additionally, specific measures such as following fertiliser bans near waterways and opting for natural compost can help reduce water pollution and protect sea turtle habitats.

Light and noise pollution

Sea turtles are extremely sensitive to both light and noise. Light and noise pollution, therefore, have a detrimental impact on their nesting and foraging habits. Unfiltered lights on beaches confuse hatchlings, causing them to wander inland, where they are at risk of dehydration, predation, or drowning. Bright city lights also deter adult female turtles from nesting on beaches, causing them to return to the ocean or nest in suboptimal locations, reducing the chances of survival for hatchlings.

To mitigate this, some coastal communities have implemented ordinances requiring residents to turn off beachfront lights during the turtle nesting season. However, these ordinances are not always enforced, and the issue of sky glow near cities remains unaddressed. Additionally, the use of special fixtures, low-pressure sodium-vapor lighting, or turtle-safe red lights can help shield beaches from artificial light. Tinting windows that face the beach and closing opaque curtains or blinds after dark can also reduce light pollution.

Persistent and abrupt low-frequency noise, such as seismic tests for energy exploration, can disturb and potentially damage the hearing of sea turtles. This noise pollution causes stress and forces turtles to move away from their preferred habitats and migratory paths, disrupting their normal behaviours. As human activities that generate ocean noise have increased, understanding how sea turtles perceive and respond to sound is crucial for developing methods to reduce the potential impacts of noise pollution on these protected species.

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