Water Pollution's Deadly Impact On Marine Life

Water pollution is a pressing issue that poses a significant threat to marine life. Marine ecosystems are vulnerable to various forms of pollution, such as plastic pollution, chemical pollution, and nutrient pollution, which can have devastating consequences for the organisms that inhabit these environments. The impact of water pollution on marine life is extensive and far-reaching, leading to entanglement, ingestion of toxic substances, habitat damage, and the creation of dead zones. It is essential to recognize the detrimental effects of water pollution on marine life and take collective action to address this critical issue.

Plastic ingestion

Marine life is extremely vulnerable to plastic pollution. The ingestion of plastic is a significant threat to marine life, and it is estimated that plastic pollution kills over 100,000 marine mammals every year.

Plastic debris in the ocean is often mistaken for food by marine animals. Seabirds, for example, have been feeding off the surface of the ocean for millennia, swooping down to scoop up small fish and algae. It is no surprise that they are now mistaking small plastic fragments that float on the water's surface for food. This mistake proves to be fatal, as the ingestion of plastic can lead to starvation, intestinal injuries, and even death. Some seabirds are able to regurgitate pieces of plastic, but many are found dead with their stomachs full of plastic waste. Northern fulmars, for instance, struggle to regurgitate plastic pellets and are now monitored as an indicator of pellet pollution levels in the North Sea.

Similarly, sea turtles often mistake plastic for food. Research indicates that half of the sea turtles worldwide have ingested plastic. Some starve after doing so, as their stomachs are full, leading them to believe they have eaten enough. In addition, plastic pollution on beaches is affecting turtles' reproduction rates by altering the temperatures of the sand where incubation occurs.

Endangered wildlife, such as Hawaiian monk seals, are also at risk. Large amounts of plastic debris have been found in their habitats, including areas that serve as pup nurseries. Even more alarming, dead whales have been found with bellies full of plastic.

Fish are not exempt from this threat. In a study summarising over 100 research papers on plastic ingestion among 500 fish species, over two-thirds had consumed plastic. Molluscs such as mussels and oysters ingest microplastics when they filter seawater to feed. A recent study of mussels sourced from UK waters found that 100% of the samples contained microplastic pieces. Fish in the North Pacific ingest 12,000 to 24,000 tons of plastic each year, which can cause intestinal injury and death, and this plastic is then transferred up the food chain to bigger fish, marine mammals, and eventually, human seafood eaters.

Entanglement in plastic

Water pollution is a pressing issue that poses a significant threat to marine life. Among the various forms of water pollution, plastic pollution stands out as a major concern, with single-use plastic being a new and growing threat to our oceans and marine life. One of the ways plastic pollution harms marine animals is through entanglement.

Some marine animals, such as humpback dolphins, have been observed with marine debris wrapped tightly around their bodies. The plastic constriction not only causes physical harm but also impedes their movement, making it difficult for them to escape predators or capture prey. This loss of mobility can have severe consequences for their survival and the overall health of their populations.

The impact of entanglement in plastic is widespread and affects a diverse range of marine species. Sea turtles, for example, are particularly vulnerable to plastic pollution. It is estimated that half of the sea turtles worldwide have ingested plastic, and entanglement in plastic debris has also been observed. This has led to a decline in their reproduction rates as the plastic pollution alters the temperatures of the sand where incubation occurs.

Efforts to address entanglement in plastic among marine life are ongoing. Organizations like NOAA Fisheries work to prevent entanglements and rescue entangled animals. They collaborate with partners to develop specialized tools and techniques to safely disentangle whales, sea turtles, and other marine creatures. These efforts are crucial in mitigating the immediate threats posed by plastic entanglement and in gathering valuable information to reduce the frequency and impact of entanglements in the future.

Eutrophication

Ocean acidification has significant impacts on marine life. It slows the growth of fish and shellfish and can even prevent shell formation in bivalve mollusks, such as oysters, clams, and scallops. These mollusks are filter feeders, and they play a crucial role in reducing nutrient levels in the water by consuming algae. However, when affected by acidification, their ability to filter-feed is compromised, leading to further imbalances in the ecosystem.

The decomposition of algae and plant matter also depletes the oxygen levels in the water, creating "dead zones" that cannot support most marine life. These dead zones are common in freshwater lakes and marine coastal environments surrounding large, nutrient-rich rivers. The elevated levels of carbon dioxide and reduced oxygen availability can lead to the death of fish and other wildlife that are unable to escape these hypoxic or anoxic zones.

Noise pollution

Sources of Noise Pollution

Over the last few centuries, human activities have increasingly altered the ocean soundscape. The primary sources of noise pollution include:

• Shipping and boating
• Energy exploration and extraction
• Industrial fishing
• Construction
• Oil drilling
• Seismic surveys
• Warfare
• Seabed mining
• Sonar-based navigation

Impact on Marine Life

The impact of noise pollution on marine life is significant and wide-ranging. Many marine animals, such as dolphins, whales, and fish, use vocalizations and echolocation to communicate, find prey, and navigate. Noise pollution can mask these natural sounds, making it difficult for them to hear and find each other, coordinate hunts, and detect predators.

For example, in an experiment, blue whales were observed to stop feeding, increase their swimming speed, and move away from the sound source when exposed to sonar, even at much lower sound levels than military sonar.

Mitigation Strategies

There are several strategies to reduce noise pollution and its impact on marine life:

• Policies to reduce propeller noise from ships and mitigate the sounds of sonar equipment, seismic air guns, pile driving, and construction.
• Developing and implementing quieter technologies, such as wind-powered ships, noise-reducing propellers, floating wind turbines, and "bubble curtains" to muffle construction noise.
• Reducing the speed of global shipping fleets, which has been shown to significantly reduce noise emissions.
• Advocating for the regulation of underwater noise and the protection of marine areas from seismic surveys and oil and gas exploration.

Light pollution

In a study published in Royal Society B, researchers found that baby clownfish near the shore raised under artificial lights had a 44% lower survival rate than those in the open sea under natural light. Light pollution has also been shown to encourage zooplankton, which are foundational to aquatic food chains, to migrate to deeper waters.

To address light pollution, better lighting practices must be implemented, and Dark Sky Reserves created near coral reefs to preserve these essential marine habitats. Protecting natural light cycles is crucial for the health and resilience of coral ecosystems, as well as for the survival of many other marine species.

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