Sea Creatures: Surviving The Pollution Crisis?

Water pollution is a pressing issue that poses a significant threat to the health and survival of sea creatures. From majestic whales to adorable turtles, a diverse array of marine life is adversely affected by human-induced pollution. The oceans, which are home to thousands of species, are inundated with plastic waste, toxic chemicals, and oil spills, endangering the delicate balance of aquatic ecosystems. Marine animals face the dual threats of pollution and overfishing, with plastic ingestion and entanglement in fishing gear being leading causes of injury and death. As pollution harms one type of sea creature, it creates a ripple effect, disrupting the entire ocean ecosystem.

Plastic ingestion

Marine life is severely impacted by the ingestion of plastic waste. The ocean is particularly susceptible to plastic pollution. Once plastic enters the sea, it can be carried by waves and storms to even the most remote areas of the ocean, where it accumulates into large gyres or becomes embedded in shorelines and coastal ecosystems.

Plastic waste in the ocean affects creatures of all sizes, from tiny seahorses to large whales. Sea turtles often mistake plastic bags for their staple diet of jellyfish, and fishing nets for seaweed. When ingested, plastic can cause turtles to feel full, leading to starvation. Research indicates that half of sea turtles worldwide have ingested plastic, and plastic pollution on beaches is also affecting their reproduction rates.

Seabirds are also highly vulnerable to plastic ingestion. They often mistake plastic floating on the ocean's surface for food, such as dead fish, carrion, or insects. When ingested, plastic can cause starvation or suffocation in seabirds. It is estimated that plastic waste kills up to a million seabirds a year.

Dolphins, despite their intelligence, are also susceptible to plastic ingestion, either directly or through contaminated prey. Sharks, as well as facing the threat of pollution, are also at constant risk of entanglement in gill nets or long lines from fishermen.

The impact of plastic ingestion on marine life can be devastating, and it is essential that we take action to address this urgent problem.

Entanglement in plastic

Sea turtles, for example, often mistake plastic bags for their natural prey, jellyfish, leading to health issues and death. Plastic waste can also entangle and harm coral reefs, which are complex and sensitive ecosystems. Dolphins, known for their intelligence, are not exempt from the dangers of plastic pollution and can choke on plastic debris. Sharks, already facing the threat of overfishing, constantly risk entanglement in gill nets or long lines from fishing activities. Seabirds, such as gulls and pelicans, often mistake plastic for food or become entangled, leading to injury or death.

The impact of plastic entanglement is not limited to a specific group of marine animals but affects a diverse range of species, including turtles, penguins, albatrosses, shorebirds, whales, dolphins, seals, manatees, sea otters, fish, and crustaceans. The problem of plastic entanglement is widespread, with debris found in all oceans, from the tropics to the poles, and even in the deepest abyssal environments.

The consequences of entanglement can be dire, leading to drowning, starvation, and debilitating injuries. Plastic debris can act as a "lethal necklace," tightening and strangling the entangled animal as it grows. It can also cause skin lesions, interrupt feeding activities, and impair predator avoidance behaviours. The very properties that make plastic desirable for human use, such as buoyancy and durability, contribute to the plethora of problems it creates in marine environments.

Addressing the issue of plastic entanglement requires a multifaceted approach, including reducing plastic waste, improving waste management practices, and transitioning to biodegradable alternatives with tightly controlled disintegration times. It is crucial to recognize the urgency of tackling this global crisis to protect the rich biodiversity of our oceans and the health of the planet.

Oil spills

Marine Mammals

Bottlenose dolphins, for example, are exposed to oil through breathing it in, eating oiled food, or swimming through it. This can lead to severe health issues. Dolphins are migratory and will often swim to safer waters if they smell or taste oil. However, oil spills can still sicken and kill them, as they can spew toxic fumes from the petroleum chemicals floating on the ocean's surface.

Sea lions, on the other hand, are territorial and less likely to flee their coastal region, even if it gets contaminated with oil. This makes them more vulnerable to oil poisoning, which can occur when they break the water's surface to breathe.

Birds

When birds are covered in oil, their feathers become useless for insulation and warmth. Birds instinctually preen themselves to remove anything on their feathers, which exposes them to ingesting toxic amounts of oil. Oiled birds returning to their nests can also contaminate their eggs and chicks.

Fish and Shellfish

Oil damages the gills of fish, making it harder for them to get enough oxygen. It can also kill fish eggs and impair the growth of young fish. Some thicker oils sink to the ocean bottom, where they are ingested by rockfish, white croakers, and other deep-sea species. While this may not kill them, the toxins accumulate in their organs, making them unfit for human consumption.

Sand Crabs

Sand crabs, also known as mole crabs, are common on many beaches and are a key link in the food chain. They burrow in the sand where surf breaks, making them vulnerable when oil washes ashore. High concentrations of oil can kill adult sand crabs, while lower amounts can harm their offspring and eggs.

Ocean acidification

The rise in ocean acidity has a two-fold impact on marine life. Firstly, it directly harms organisms that build shells and skeletons out of calcium carbonate, such as corals, sea urchins, sea snails, oysters, and clams. The more acidic the ocean becomes, the faster their shells dissolve. These organisms have to expend extra energy to repair or thicken their shells, which can negatively affect their growth and reproduction. Even if they survive, they tend to become smaller, which can have knock-on effects on the food chain.

Secondly, the increased acidity also affects other organisms higher up the food chain that feed on these shell-building organisms. For example, whales and humans are impacted when the populations of their food sources decline. Additionally, harmful algal blooms, which produce toxins, are more prevalent in acidic waters, posing a threat to both marine life and humans who consume contaminated shellfish.

Toxin bioaccumulation

Bioaccumulation of toxins can also directly affect humans, who are at the top of the marine food web. People can get very sick or even die from consuming seafood containing high levels of toxins that have built up through this process. Shellfish, in particular, have been known to cause illnesses in people due to the toxins they retain from phytoplankton.

Mercury, in the form of methylmercury, is one example of a toxic substance that can bioaccumulate in fish and shellfish. Other toxic metals and chemicals caused by pollution can also be incorporated into marine food webs, leading to adverse effects on both marine life and humans.

The accumulation of toxins through bioaccumulation can have far-reaching consequences for the health of marine ecosystems and human populations that depend on seafood as a source of nutrition. It is important to understand and address the issue of toxin bioaccumulation to ensure the safety and sustainability of marine environments and the organisms within them.

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