Tag Archives: ocean pollution

Forever Dead Products

Yangtze river

In a paper published in 2107 in Science Advances, Roland Geyer of the University of California, Santa Barbara, and his colleagues put the cumulative amount of solid plastic waste produced since the 1950s that has not been burned or recycled at 4.9bn tonnes. It could all have been dumped in a landfill 70 metres deep and 57 square kilometres in area—that is to say, the size of Manhattan

If only it had all remained on land, or even washed up on beaches, where it could be collected. A bigger environmental worry is that much plastic has ended up in the ocean, where, dispersed by currents, the stuff becomes virtually irretrievable, especially once it has fragmented into microplastics. Computer models suggest that seas hold as many as 51trn microplastic particles. Some are the product of larger pieces breaking apart; others, like microbeads added to toothpaste or face scrubs, were designed to be tiny….

Even if the flow of plastic into the sea, totalling perhaps 10m tonnes a year, was instantly stanched, huge quantities would remain. And the flow will not stop. Most of the plastic in the ocean comes not from tidy Europe and America, but from countries in fast-developing East Asia, where waste-collection systems are flawed or non-existent. In October 2017 scientists at the Helmholtz Centre for Environmental Research, in Germany, found that ten rivers—two in Africa and the rest in Asia—discharge 90% of all plastic marine debris. The Yangtze alone carries 1.5m tonnes a year

Trucost, a research arm of Standard & Poor’s, a financial-information provider, has estimated that marine litter costs $13bn a year, mainly through its adverse effect on fisheries, tourism and biodiversity. It puts the overall social and environmental cost of plastic pollution at $139bn a year. Of that half arises from the climate effects of greenhouse-gas emissions linked to producing and transporting plastic. Another third comes from the impact of associated air, water and land pollution on health, crops and the environment, plus the cost of waste disposal.

Exerpts from:  Plastic Pollution: Too Much of a Good Thing, Economist, Mar. 3, 2018, at 51

Production, use, and fate of all plastics ever made (R. Greyer et al., 2017)

The Trash Islands

According to a three-year study published in Scientific Reports on March 23, 2018, the mass known as the Great Pacific Garbage Patch is about 1.6 million square kilometers in size — up to 16 times bigger than previous estimates. That makes it more than double the size of Texas.  Ghost nets, or discarded fishing nets, make up almost half the 80,000 metric tons of garbage floating at sea, and researchers believe that around 20% of the total volume of trash is debris from the 2011 Japanese tsunami.

The study — conducted by an international team of scientists with The Ocean Cleanup Foundation, six universities and an aerial sensor company — utilized two aircraft surveys and 30 vessels to cross the debris field.

Along with nets to survey and collect trash, researchers used two six-meter-wide devices to measure medium to large-sized objects. An aircraft was also fitted with advanced sensors to collect 3D scans of the ocean garbage. They ended up collecting a total of 1.2 million plastic samples and scanned more than 300 square kilometers of ocean surface.  The bulk of the pile is made up of larger objects while only 8% of the mass is microplastics, or pieces smaller than 5 millimeters in size.

The patch is so big that last fall environmentalists called on the United Nations to declare the Great Pacific Garbage Patch a country, called “The Trash Isles,” complete with its own passport and currency, called debris…Research scientist Britta Denise Hardesty, who wasn’t involved in this study, said while discarded nets may make up almost half of the findings, the problem may be more nuanced.  It’s estimated 640,000 tons of fishing gear is lost to the marine environment each year.

Excerpts from A massive garbage patch in the middle of the Pacific Ocean is now three times the size of France, CNN, Mar. 24, 2017

Turning Oceans into Muck

image from http://recon.sccf.org/events

Oxygen is critical to the health of the planet. It affects the cycles of carbon, nitrogen and other key elements, and is a fundamental requirement for marine life from the seashore to the greatest depths of the ocean. Nevertheless, deoxygenation is worsening in the coastal and open ocean. This is mainly the result of human activities that are increasing global temperatures (CO2-induced warming) and increasing loads of nutrients from agriculture, sewage, and industrial waste, including pollution from power generation from fossil fuels and biomass.

Facts: During the past 50 years the area of low oxygen water in the open ocean has increased by 4.5 million km2. The world’ oceans are now losing approximately  1 gigaton of oxygen each year.

The Millennium Ecosystem Assessment released by the UN in 2005 reported that nitrogen containing compounds (e.g. sewage, fertilizers) release into the oceans grew 80 percent from 1860 to 1990.

Increasing temperatures will reduce the capacity of the ocean to hold oxygen in the future;
Oxygen deficiency is predicted to worsen in estuaries, coastal areas and oxygen minimum zones in the open ocean;
The ocean’s capacity to produce oxygen will be reduced in the future.
Habitat loss is expected to worsen, leading to vertical and horizontal migration of species;
Oxygen deficiency will alter biogeochemical cycles and food webs;
Lower oxygen concentrations are projected to result in a decrease in reproductive capacity and biodiversity loss;
There are important local decreases of commercially important species and aquaculture production;
Harmful Algal Blooms will be exacerbated from nutrients released in bottom waters due to hypoxia (e.g. in the Baltic Sea);
Reduced ocean oxygen concentrations will lead to an increase in greenhouse gas emissions, thereby initiating feedbacks on climate change;

Excerpts from UNESCO, Jan. 2018

View Extensive Abstract

Background paper (pdf)

Global Ocean Oxygen Network: Through the participation of high level scientists from across the world, the IOC expert group, the Global Ocean Oxygen Network GO2NE, established in 2016, is committed to providing a global and multidisciplinary view of deoxygenation, with a focus on understanding its multiple aspects and impacts.

Radioactive Beaches: Fukushima at 2017

Kotohiki Beach, Japan. image from wikipedia

Six years after the Fukushima nuclear reactor disaster in Japan, radioactive material is leaching into the Pacific Ocean from an unexpected place. Some of the highest levels of radioactive cesium-137, a major by-product of nuclear power generation, are now found in the somewhat salty groundwater beneath sand beaches tens of kilometers away, a new study shows.

Scientists tested for radioactivity at eight different beaches within 100 kilometers of the plant, which experienced three reactor meltdowns when an earthquake and tsunami on March 11, 2011, knocked out its power. Oceans, rivers and fresh groundwater sources are typically monitored for radioactivity following a nuclear accident, but several years following the disaster, those weren’t the most contaminated water sources. Instead, brackish groundwater underneath the beaches has accumulated the second highest levels of the radioactive element (surpassed only by the groundwater directly beneath the reactor).

In the wake of the 2011 accident, seawater tainted with high levels of cesium-137 probably traveled along the coast and lapped against these beaches, proposes study coauthor Virginie Sanial, who did the work while at Woods Hole Oceanographic Institution in Massachusetts. Some cesium stuck to the sand and, over time, percolated down to the brackish groundwater beneath. Now, the radioactive material is steadily making its way back into the ocean. The groundwater is releasing the cesium into the coastal ocean at a rate that’s on par with the leakage of cesium into the ocean from the reactor site itself, Sanial’s team estimates.

Excerpts from Radioactive material from Fukushima disaster turns up in a surprising place, Science News, Oct. 2, 2017

See also Unexpected source of Fukushima-derived radiocesium to the coastal ocean of Japan

Looking Desperately for the Pristine

Not far off the coast of Guam lies the deepest point on Earth’s surface, the Mariana trench. Its floor is 10,994 metres below sea level. If Mount Everest were flipped upside down into it, there would still be more than 2km of clear water between the mountain’s base and the top of the ocean. Such isolation has led many to assume that it and similar seabed trenches will be among the few remaining pristine places on the planet. However, a study led by Alan Jamieson of Newcastle University, in England, has shown that nothing could be further from the truth. As Dr Jamieson and his colleagues report this week in Nature Ecology and Evolution, trenches are actually loaded with pollutants….

No vents are known to exist below 5,000 metres, though, and no sunlight penetrates a trench. The organisms found in them thus depend entirely on dead organic material raining down upon them from far above.  Since these nutrients, having once flowed into a trench, never make their way out again, Dr Jamieson found the notion that trenches have somehow remained untouched by human activities questionable. He suspected that long-lived pollutants such as polychlorinated biphenyls (which were once used widely in electrical equipment) and polybrominated diphenyl ethers (employed in the past as flame retardants) might have made their way into the bodies of organisms living in trenches.

To test this idea out, he and his colleagues sent an unmanned lander to the bottom of the Mariana trench and also to the bottom of the Kermadec trench, near New Zealand. This lander fell to the seabed and spent between eight and 12 hours there, capturing amphipods (a type of crustacean,) using funnel traps baited with mackerel. At the end of its mission it jettisoned some ballast and floated back to the surface with its prey.
When the team looked for pollutants in the captured amphipods, they found that polybrominated diphenyl ethers were indeed present, but at moderate concentrations. Levels of polychlorinated biphenyls, however, were almost off the scale.

Exceprts Oceanic pollution: Entrenched, Economist, Feb. 18, 2017, at 67


Floating Power Plants: the Cayman Islands

otec floating power plant

A United States company OTEC International is in talks with Caribbean Utilities Company (CUC), Grand Cayman’s electrical provider, to supply renewable energy to the island via Ocean Thermal Energy from a platform at North Side.  According to the company:

“The Cayman Islands has documented its storm history with precision, which made it easier for OTEC International to identify locations where  Floating Power Platforms (FPPs) can be securely sited and appropriately designed to survive strong storm conditions.  The first phase of the Cayman project would be the generation of 6.25-MW renewable electricity* from an FPP that would be permanently moored less than a mile from shore. At this distance from shore, the plant’s visual impact will be minimal because of the platform’s overall low profile. The power generated would be transported to a substation onshore via cable and connected to the island’s CUC grid…..A comprehensive Environmental Impact Assessment (EIA) will be completed before the project can receive all necessary licenses and permits from various governmental authorities.”

*This type of ocean-thermal electricity plant takes advantage of the temperature difference between warm surface water and cold deep seawater.

Excerpts from Company providing floating ocean power platform technology to supply renewable energy to Cayman Islands in talks, Cayman inews, Sept. 21, 2014


The Plastic in the Oceans

Marine debris on Hawaiian coast. Image from wikipedia

The steady build-up of garbage in the world’s oceans is a “tremendous challenge” and a growing threat to the planet’s marine ecosystems with the potential for “significant socio-economic consequences,” the United Nations Environment Programme (UNEP) heard today.  In the final day of the 16th Global Meeting of the Regional Seas Conventions and Action Plans, held in Athens, Greece, scientists, policymakers and delegates gathered amid growing global concern over the accumulation of plastic waste in oceans and seas – a problem that could pose an estimated $13 billion in damage to marine life and habitats, and which demands a comprehensive remedy.

Addressing the meeting, Jacqueline Alder, Coordinator of UNEP’s Freshwater and Marine Ecosystem Branch, applauded the creation of a “visioning roadmap” seeking to chart a way forward for oceans governance in the coming decade, particularly in the areas of extraction, governance, impacts of a changing climate, ocean acidification, and pollution.

The meeting generated broad agreement among experts and policymakers regarding the issue of microplastics – tiny pieces of plastic less than one millimetre in size – which, they said, deserved more attention in order to better grasp their physical and biological impact on the marine ecosystems they pollute.  In addition, they advised a three-tier approach tackling marine litter at the national, regional and municipal levels as municipalities tends to have responsibility for solid-waste management….

The five garbage patches, or gyres, that have amassed in the world’s oceans as plastic waste and other jettisoned materials are carried by the currents. The patches themselves now occupy a total of 15, 915, 933 square kilometres of ocean, threatening the marine environment and the plants and animals living within it.

UN meeting hears call for greater marine protections as plastic waste accrues in oceans, UN Press. Release, Oct. 1, 2014