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Biodiversity And Trawling Bans | Earth Wise

June 7, 2021 By EarthWise Leave a Comment

Trawling is a method of commercial fishing that involves pulling or dragging a fishing net – called a trawl – through the water or across the seabed in hopes of catching fish. Commercial fishing companies favor towing trawl nets because large quantities of fish can be caught in one go.

However, the trouble with trawling is that it’s destructive to the seafloor and indiscriminate in what it catches. When towing these large trawl nets, the largest of which is reportedly big enough to catch thirteen 747 jets, everything that happens to be in the way gets caught. As a result, trawling results in lots of bycatch, a fishing industry term used to describe the deaths of non target species during the process.

In 2012, the Hong Kong government implemented a territory-wide trawling ban in its waters in hopes of rehabilitating the marine benthic habitat. The benthic zone refers to the ecological region at the bottom of the ocean.

Researchers from City University of Hong Kong collected sediment samples from 28 locations six months before the trawl ban and two and a half years after the trawl ban to see whether such interventions can facilitate ecosystem recovery.

According to the study, which was recently published in the journal Communications Biology, the ban on trawling significantly improved marine biodiversity. The researchers observed substantial increases in the richness of species and the abundance of benthic marine organisms following the trawling ban. And since small benthic organisms are the main source of food for large species like fish and crabs, the trawling ban actually helps support fisheries.

More governments should consider a trawl ban to promote sustainable fisheries and marine biodiversity conservation.

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Research confirms trawl ban substantially increases the abundance of marine organisms

Photo, posted December 4, 2018, courtesy of John via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

PPE Pollution | Earth Wise

June 25, 2020 By EarthWise Leave a Comment

While the COVID-19 pandemic and its shutdown of so many human activities has reduced many kinds of pollution, it has also managed to create a new source of pollution: face masks and sanitary gloves.

Divers from a French non-profit organization called Operation Clean Sea are already finding gloves, masks, and hand sanitizer bottles beneath the waves of the Mediterranean, along with the usual litter of disposable cups and aluminum cans. In France, authorities have ordered 2 billion disposable masks. Given that, there may soon be the risk of having more masks in the Mediterranean than jellyfish. In Hong Kong, face masks have been piling up on beaches and nature trails. Even in Hong Kong’s isolated and uninhabited Soko Islands, dozens of masks are showing up on a small stretch of beach.

Disposable masks may feel like soft cotton, but almost all of them are made from non-biodegradable material such as polypropylene. When such masks are discarded into storm drains, they end up in rivers and seas. With a lifespan of hundreds of years, these masks are an ecological timebomb. Land-based activity accounts for 80% of ocean pollution, and half of that is a direct result of single-use plastics. Many of the CDC’s recent recommendations for reopening offices and businesses actually recommend the increased use of them, and for sensible reasons.

The best we can all do is to wear reusable masks and to try to wash our hands more often rather than putting on another pair of latex gloves. Given that there are alternatives, we don’t need to make plastic the solution to protect us from Covid-19.

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COVID-19 Masks Are Polluting Beaches and Oceans

Photo, posted March 28, 2020, courtesy of Michael Swan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Electric Cars In Norway

February 18, 2019 By EarthWise Leave a Comment

Norway has long been a world leader in sales of electric vehicles. The country only has 5.3 million people, so the absolute numbers cannot compete with those of large countries. Despite that, it wasn’t until the first quarter of last year that Germany became the leader in number of electric cars sold in Europe and Germany has 15 times the population of Norway.

In percentage terms, almost one-third of all new cars sold in Norway last year ran on batteries. The country offers generous subsidies for buyers who opt to go electric. The government has set a goal of having all new cars be emission-free by 2025. Last year, three of the top five most popular new car models were electric: the Nissan Leaf, the BMW i3, and the Tesla Model X.

Tesla’s Model 3, which has shattered all records for electric car sales in the United States, has yet to go on sale in Norway. When the car becomes available there in the next few months, it is expected to generate very high sales figures.

The 31% market share for electric cars in Norway far exceeds that of most other countries. In the United States, for example, plug-in cars account for only about 2% of new car sales. Only Hong Kong and Iceland are also currently above 5% electric.

Norway’s role in all of this is rather convoluted. The country has copious hydroelectric power resources that provide virtually all of its electricity. Thus, electric cars in Norway are truly clean, green vehicles. On the other hand, Norway is the 15th largest producer of oil in the world and gets about 17% of its GDP from oil exports. Tackling climate change must ultimately deal with the emissions Norway continues to export.

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Photo, posted October 3, 2018, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A See-Through Heat Shield

January 8, 2019 By EarthWise Leave a Comment

It is estimated that air conditioners use about 6% of all the electricity produced in the United States for an annual cost of $29 billion. With rising temperatures, this expense is only going to get larger.

A significant part of the heat load in buildings arises from heat coming through windows. It turns out that for every square meter of window, about 500 watts of heat energy can be brought in by sunlight, equivalent to 5 old-fashioned light bulbs.

Researchers at MIT and the University of Hong Kong have developed a heat-rejecting film that can applied to a building’s windows that will reflect 70% of the sun’s incoming heat. The film is similar to transparent plastic wrap. It remains highly transparent at temperatures below 89 degrees Fahrenheit. Above that temperature, tiny microparticles embedded in the film shrink and the film becomes more translucent or frosted, still letting in a good amount of light, but rejecting a lot of heat.

There are already so-called smart windows on the market, similar to the electrochromic mirrors in cars that darken to prevent trailing headlights from blinding drivers. But that technology is not very effective in rejecting heat and it requires power to operate, which means you would have to pay to turn windows opaque.

Tests of the new film demonstrated its ability to reject heat and lower temperatures. The researchers estimate that if every exterior-facing window in a building were covered in the heat-rejecting film, the building’s air conditioning and energy costs could drop by 10%. Saving ten percent of tens of billions of dollars is no minor matter.

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See-through film rejects 70 percent of incoming solar heat

Photo courtesy of MIT researchers/MIT.

Earth Wise is a production of WAMC Northeast Public Radio.