The Looming Threat: Water Pollution And Sea Animals' Survival

Water pollution is a critical issue that poses a significant threat to marine life and ecosystems. Plastic pollution, in particular, has become rampant, with an estimated 13 million tons of plastic waste entering our oceans each year. This waste breaks down into microplastics, which are ingested by marine animals, leading to entanglement, ingestion, and chemical contamination. The impact of plastic pollution on marine life is devastating, and species such as sea turtles, whales, dolphins, and coral reefs are among the most vulnerable. Climate change further exacerbates the problem, as warming waters can lead to decreased oxygen levels and the expansion of dead zones where water quality is too poor to sustain life. With the delicate balance of marine ecosystems already disrupted by pollution, the combined effects of water pollution and climate change could have far-reaching consequences for sea animals. While it is challenging to predict exactly when water pollution will wipe out sea animals, the current trends suggest a grim future if urgent action is not taken to address this urgent problem.

Plastic pollution is a critical threat to marine life

Marine life has existed in the sea for 6.6 million years, and for 300,000 of those years, modern humans have been around. In the last century, humans have managed to undo the millions of years of evolution the ocean has undergone. One of the most critical threats to marine life is plastic pollution.

Plastic is perhaps the most well-known pollutant, and for good reason. It is made from raw materials like natural gas, plants, and oil, as well as harmful chemical additives that enhance durability and flexibility. When plastic waste enters the ocean, other contaminants are attracted to it, causing a double whammy of harm to marine animals that ingest it. Plastic often looks and smells like food to marine life, and it also attracts things like algae and biological life, making it even more enticing to unsuspecting creatures. As plastic breaks down into micro and nano particles, it proliferates through the food web.

The effects of plastic pollution on marine life are severe and diverse. Marine plastics are contributing to the death of more than 100,000 marine mammals every year. Large items of plastic can entangle marine mammals and fish, leading to starvation, injury, and increased vulnerability to predators. Small plastic fragments can be mistaken for food by seabirds and other marine species, causing suffocation, starvation, and toxic contamination. Microplastics, in particular, are highly susceptible to accumulation in biota through ingestion, with harmful impacts. They can also adsorb toxins, which can then be transferred to the fatty tissues of the organisms that ingest them.

The degree of impact by plastic pollution on marine biodiversity is severe, and it has been identified as one of the top threats to biota. According to Gall and Thompson (2015), over 30,000 individuals belonging to 243 species have encountered issues related to ingestion of plastic, while thousands of others have faced entanglement in plastic debris. Plastic pollution also has socio-economic impacts, as it affects the livelihoods of people who depend on marine ecosystems.

While it is challenging to predict exactly when water pollution will wipe out sea animals, it is clear that plastic pollution is a critical threat to marine life. The weight of ocean plastics is predicted to exceed the combined weight of all the fish in the seas by 2050 unless urgent action is taken.

Climate change and warming waters reduce oxygen levels

While it is challenging to predict exactly when water pollution will wipe out sea animals, climate change and warming waters reducing oxygen levels are significant contributors to this impending ecological disaster.

The Earth's oceans have endured periods of warming and cooling over billions of years, and museum scientists study these past climate changes to forecast the future of ocean animals. Research shows that as temperatures increased in the past, oxygen levels decreased, and vast seafloor areas became uninhabitable. Warm water can hold less oxygen, creating a significant problem for marine life.

Direct measurements reveal that global ocean oxygen levels have decreased by approximately 2% in the last 50 years, with climate change being the primary culprit. This "deoxygenation" affects the amount of oxygen seawater can hold and the circulation patterns that deliver oxygen-rich water to the deeper ocean. As a result, there are now various pockets with low or no oxygen in the global oceans, including parts of the tropical oceans off California, Peru, and Namibia, and the subsurface waters of the Arabian Sea.

Warming waters have multiple detrimental effects on oxygen levels. Firstly, they alter patterns of global ocean circulation, disrupting the mixing of oxygen-rich surface waters with deeper oxygen-poor waters. This reduced mixing further depletes the oxygen available for marine life. Secondly, warmer waters increase the oxygen demand from living organisms, intensifying the strain on already diminishing oxygen supplies.

Additionally, warming-driven deoxygenation can influence the movement of gases between the ocean and the atmosphere. Deoxygenated deeper ocean waters produce greenhouse gases such as nitrous oxide, carbon dioxide, and methane, which may be released into the atmosphere, contributing to further warming and exacerbating the oxygen depletion in the oceans.

The consequences of these changes are severe. As oxygen levels decline, "dead zones"—areas of the ocean with water quality too poor to sustain life—expand. Any animal with gills, including fish, oysters, octopuses, and crabs, will suffer. Even animals that breathe air, like whales and turtles, will not be immune to the impacts, as their food sources diminish or become contaminated.

Pollution and warmer waters are a deadly combination

It is difficult to predict exactly when water pollution will wipe out sea animals, but the combination of pollution and warming waters is undoubtedly deadly.

Thermal Pollution

Thermal pollution is primarily caused by industrial sources, with nuclear power plants being the greatest contributor. These plants withdraw water to cool their generators and machines, and then release it back into water bodies, causing a significant increase in the temperature of freshwater habitats. This has a devastating impact on aquatic life, as the sudden temperature change can kill fish and other organisms adapted to a particular temperature range. The elevated temperature also decreases the level of dissolved oxygen in the water, harming aquatic animals such as fish, amphibians, and other organisms with gills, like oysters and crabs.

Ocean Warming

The warming of the oceans is a slow process, but the rate at which it is occurring is alarming. As the oceans absorb more heat, they contribute to rising sea levels, altered ocean circulation patterns, and the fueling of extreme weather events. Warmer waters also hold more carbon dioxide, leading to ocean acidification, which harms corals, clams, snails, and many other marine organisms by dissolving their calcium carbonate shells and skeletons. Additionally, warmer waters encourage marine heatwaves, increasing the risk of massive bleaching events on sensitive coral ecosystems.

Pollution

Plastic pollution is a significant concern, with an estimated one million seabirds and one hundred thousand marine mammals killed by plastic annually. Animals become entangled in plastic, unable to escape from predators or access food. Chemical pollution is another issue, with toxins building up in the ear canals of whales, for example.

The combination of pollution and warming waters is a deadly threat to marine life. The warming of the oceans exacerbates the effects of pollution, creating a hostile environment that many sea animals cannot survive in. While it is challenging to predict exactly when water pollution will wipe out sea animals, the current trajectory suggests that the situation is urgent and requires immediate action to prevent catastrophic loss.

Chemicals and noise also affect marine life

While plastic pollution is a well-known issue, it is not the only source of pollution in the ocean. Chemicals, light, and noise also affect marine life.

Chemicals are often present as additives in plastics, enhancing their durability and flexibility. These additives are harmful to marine life, which can ingest plastic waste. Furthermore, other contaminants are attracted to plastic waste in the ocean, leading to a higher risk of ingestion by marine animals. This ingestion can cause suffocation, starvation, and drowning. The breakdown of plastics into micro and nano-particles has led to their proliferation through the food web, even finding their way into human bloodstreams.

In addition to chemicals, noise pollution from ships, sonar equipment, seismic air guns, and construction can cause a range of issues for marine life. It can interfere with key life functions, causing temporary or permanent hearing loss, behavioural and physiological changes, masking, injury, and even death. Noise pollution also decreases the communication range of marine mammals, causing them to change their vocal behaviour. For example, bottlenose dolphins have been recorded simplifying their vocal calls when exposed to increased ship noise.

The effects of noise pollution on marine life are species-specific and can vary depending on the life stage of the organism. Studies have shown that noise can cause auditory masking, leading to cochlear damage, changes in behaviour, altered metabolisms, and hampered population recruitment. It can also affect sound-based orientation and communication, particularly in reproductive contexts, and increase the risk of mortality by unbalancing predator-prey interactions.

To mitigate the impacts of noise pollution, policies and quieter technologies are needed to reduce propeller noise from ships and sonar equipment. By addressing these issues, we can improve the ocean soundscape and potentially enable the recovery of some marine life.

The impact of pollution extends beyond the ocean

Marine pollution is a combination of chemicals and trash, most of which comes from human activities along coastlines and far inland. The oceans are the endpoint for much of the pollution we produce on land, however far from the coasts we may be. The impact of pollution extends beyond the ocean, affecting not just marine life but also birds, bears, big cats, and wolves that rely on fish for food. As a result, the damage ricochets up the food chain, ultimately reaching us, too. For example, the consumption of contaminated fish is one reason why microplastics have been found in human bloodstreams.

The majority of the garbage that enters the ocean each year is plastic, which can persist in the environment for hundreds of years, polluting our beaches, entangling marine life, and getting ingested by fish, whales, turtles, and seabirds. Plastic waste is particularly problematic as a pollutant because it is so long-lasting. Plastic items can take hundreds of years to decompose, and in the meantime, they pose dangers to both humans and animals. Fish become tangled and injured in the debris, and some animals mistake items like plastic bags for food and eat them. Small organisms feed on tiny bits of broken-down plastic, called microplastics, and absorb the chemicals from the plastic into their tissues.

Another source of pollution is oil spills, which can do irreversible damage to delicate marine ecosystems. Even the most advanced cleanup efforts only remove a fraction of the oil, and sometimes they use hazardous technologies. Chemical dispersants, for example, are dangerous pollutants themselves. In addition to oil spills, the oil and gas industry's routine operations emit toxic by-products, release high levels of greenhouse gases, and contribute to ocean noise pollution.

Nonpoint source pollution, which occurs as a result of runoff, is another major source of pollution. This can come from many sources, like septic tanks, vehicles, farms, livestock ranches, and timber harvest areas. Fertilizer from farms can lead to the runoff of chemicals into waterways that ultimately flow into the ocean, promoting the growth of algal blooms that can be toxic to wildlife and harmful to humans.

While it is not possible to determine exactly when water pollution will wipe out sea animals, it is clear that the impact of pollution extends far beyond the ocean and that urgent action is needed to address this urgent problem.

Frequently asked questions