The threat to the ocean: is it all plastic, or something else?
The threat to the ocean: is it all plastic, or something else?
| Author: Patrick Semadeni
Beaches full of plastic garbage. Enormous blankets of plastic in the ocean. We see these pictures on a daily basis. Is plastic the main problem?
Everything that lands in the ocean...
Plastic
Plastic pollution in the world’s ocean’s is a problem, no doubt. Between 5 and 13 million tons of plastic make it into the ocean every year. This pollution is primarily due to a lack of environmental awareness and waste infrastructure in developing and emerging countries in Asia and Africa. 97% of plastic waste in the ocean comes from outside of Europe!1
"The impression is often given that plastic trash is the true scourge of the seas. But that’s a devastating misjudgment."
Nikolaus Gelpke, Marine Biologist3
Fertilizer, chemicals, hormones...
Nutrients (nitrogen-based) make it into the ocean as a result of agriculture. They are beneficial to the growth of algae. The effect is that water is deprived of oxygen, which is essential to other sea dwellers.
Pesticides and other toxins also make it into the water due to both agricultural and industrial use. These substances, such as PCB, DDT, and heavy metals like mercury, are persistent and accumulate in our food chain.4
Professor Dr. Bernhard Wehrli of the ETH Zürich sees a larger threat than plastic pollution in the ocean in this matter: “Hormones and pesticides are up to 100,000 times more harmful. Because these have a biological impact, and in fact were designed for just that. They are soluble and easily absorbed.” He adds: “I do not believe that microplastics are a danger to us.”5
Oil
The use of oil continually causes spills that persist for decades. 46% originate from land-based sources, 32% from the operation of oil tankers, and 13% from offshore oil drilling.4
Mercury
Mercury likewise enters the ocean and is transformed into the highly toxic methylmercury through chemical conversion processes. This accumulates in the food chain. Bigger predators such as tuna are the most strongly affected by this – a fish that quite often ends up on our plates.6
Heavy metals
The heavy metals lead and cadmium have been found in many of the fish we eat. The following species of fish were investigated in a study regarding this in 2017: mackerel, salmon, eel, trout, and sprats. The popular salmon, for example, was found to contain an average of 57.81 micrograms of lead per kilogram.7
These are alarming findings. The German Federal Ministry for the Environment writes on their website: „In April of 2010, the European Food Safety Authority (EFSA) published a report on lead in food. In evaluating academic studies on the toxicity of lead to humans, the EFSA found no effect threshold below which damage to human health could safely be ruled out; this conclusion was affirmed by the UN’s Joint Expert Committee on Food Additives (JECFA) in June of 2010. Both reports indicate that humans, and above all particularly sensitive groups such as small children and pregnant women, respond much more sensitively to lead intake than was previously assumed. The contamination of food by the heavy metal lead is therefore much less acceptable today than it was before in light of the new findings.”8
The ocean is getting more acidic
When fossil energy sources are burned, the exhaust gases don’t just go into the air. Water surfaces absorb about a quarter of the emissions. This alters the pH value in the top layers of the water and make the ocean more acidic. This process is happening faster than in the last 300 million years! 2Since the beginning of industrialization alone, the pH value has increased by 30%. Marine biologist Nikolaus Gelpke describes the consequences: “The sudden and massive change in the pH value is causing these systems to change. Coralline algae such as coccolithophorids – a type of plankton and thus a foundation for life in the ocean and the essential base of the food chain – are losing their calcareous shells; calcification in corals, snails, and mussels is decreasing by 22 to 39 percent; calcifying marine organisms show up to 17 percent less growth. The effects of acidification do not just impact individual organisms, but alter the entire ecosystem.”3
However, acidification is also causing coral reefs to be bleached out. These color stimuli are important to many sea dwellers for orienting themselves and hunting for food.2
The ocean is becoming hotter
The oceans are also heating up in the course of climate change. Marine biologist Nikolaus Gelpke explains: “the coral reefs are one well-known victim of the rising temperatures: Even an increase of one to two degrees can cause what is known as coral bleaching, and is responsible for 20% of irreversibly destroyed reefs and over 30% of those that are heavily damaged. Fish, too, such as the codfish, suffer from the rising temperature: An increase of just three degrees Celsius allows up to 40% of spawn, or embryos, to die, and acidification exacerbates this effect. A similar impact is seen amongst sea bass, mussels, and scallops. The codfish has long since become scarce in the Baltic Sea and wandered into waters further north.”3
The ocean is getting louder
Water conducts sound waves better than air. A number of sea dwellers emit sounds to communicate, with well-known examples being whales and dolphins. Around 60,000 cargo ships and container ships are perpetually on the high seas today. Noise emissions are able to spread easily in the water and disturb the sensors of many sea dwellers. Another problem is special ships that are looking for oil deposits and emit blasts of compressed air every 10-12 seconds to do this, which can be felt from up to 2,500 miles away by a whale’s sensitive sensors.2
The ocean is getting emptier - overfishing
Today, every human eats 19.2 kg of fish per year – this is around twice the average of 50 years ago. Just under 80 million tons of saltwater fish were caught globally in 2012. The global fish population went back up by 50% between 1970 and 2010.9
The numbers for popular food fish such as swordfish, mackerel, and tuna even went back up by 90%! This changes the ocean’s ecosystem. Fishing also leads to too much by-catching: turtles, dolphins, sharks, and sea birds. By-catches are thrown back into the sea, but the animals are often already dead by this point.10
Fishing with “bottom trawlers,” as they are known, is also destructive – nets fish along the sea floor and destroy the corals and marine plants growing there.10
Conclusion: there are many threats to the ocean
Plastic garbage is not the biggest factor in the matter. However, plastic waste does not belong in the ocean, and improved waste management in countries that contribute the most waste (China, southeast Asia) should reduce their pollution levels.
The subject hyped by the media, however, must not distract from the other, more dangerous, threats to the ocean. The media has an environmental responsibility in this matter.
1 European Commission, A European Strategy for Plastics in a Circular Economy, Brüssel, 16.01.2018
2 Ocean Pollution, The Dirty Facts, National Resource Defence Center NRDC, New York, 2018
3 Plastik im Meer ist ein Problem – doch bei weitem nicht das grösste, Nikolaus Gelpke in NZZ, Zürich, 15.08.2018
4 Sources an Effects of Marine Pollution; Global Development Research Center GDRC, Kobe, 2019
5 «Herr Professor, wie gefährlich ist Mikroplastik im Darm?», Prof. Dr. Bernhard Wehrli im Tagesanzeiger, Zürich , 26.10.2018
6 Marine Algensedimente als riesige Quecksilberspeicher, Analytik News, Ober Ramstadt, 2018
7 Cadmium and Lead Content in Chosen Commercial Fishery Products Consumed in Poland and Risk Estimations on Fish Consumption, Winiarska-Mieczan et. al. , Lublin, 2017, publiziert bei NCBI National Center for Biotechnology Information, US National Library of Medicine, Bethesda
8 Bundesministerium für Umwelt, Naturschutz und nukleare Sicherheit BMU, Website, „Blei in Lebensmitteln – Hintergrundinformationen“, Stand 22.07.2015, Berlin
9 Fish Forward Projekt, WWF-EJF, Website, 2019
10 Oceana – Protecting the World’s Oceans, Website, Washington, 2019