Mankind leaves its mark on the ocean in many ways: shipping, fishing, pollution, drilling and other impacts. But how much of the world’s oceans are still pristine? The answer: roughly 13%. Those untouched areas are mostly in the frigid polar seas and the remotest parts of the Pacific Ocean. Although these areas are havens for biodiversity, less than half of these seas are protected waters. Via Science Magazine
Although the tropics cover just 40% of the planet, they are home to more than 75% of all species including almost all shallow-water corals and more than 90% of the world’s bird species. These tropical ecosystems — tropical forests, savannas, lakes and rivers, and coral reefs — are seriously threatened by habitat destruction and endangered by global warming, and a new report claims that time is running out to protect them. Via Science Daily
Sea urchins eat kelp, sea otters eat the urchins, and the kelp forests protect the otters, but it turns out that sea stars have an important effect on preserving the ecosystem, too. Researchers noted that otters prefer to eat large urchins, and the most effective predator of smaller urchins are sunflower sea stars. When sea star wasting disease wiped out nearly the entire sunflower sea star population in 2015, researchers noted a four-fold increase in the number of small urchins and a 30% decline in the amount of kelp. Now we know that for a kelp forest to be healthy, it needs sea stars too. Via Vancouver Sun
The consensus is that humpback whales sing to communicate, mostly to find mates, but there isn’t much evidence of whales changing behaviour as a result of hearing other whales sing. A psychologist has proposed that their complex song is not a form of communication, but a particularly sophisticated multi-frequency sonar system. He admits that most biologists won’t agree with him, but maintains that the hypothesis is worth testing. Via EurekAlert!
Cleaning up beaches takes a toll on wildlife, it turns out. Machines remove an average of 10 tons of garbage from Santa Monica’s public beach each morning (the peak is 40 tons in a day). Most of this is plastic dropped by beachgoers or washed out of the city’s storm drains. But the machines also pick up invertebrates and the seaweed that they feed on, which in turn harms the birds that feed on them. Now the city has fenced off a small area to keep the visitors and grooming machines out, and wildflowers and nesting birds have returned to Santa Monica beach. Via Hakai Magazine
Water Quality and Supply
Fruit and vegetable peels are good at removing pollutants, such as lead and copper, from water through surface adsorption. While it may not work as an industrial process, when boiled (to remove surface impurities) and then dried, lemon seeds and okra peel can remove 100% of lead ions, while lemon peels remove 96%. Via EurekAlert!
Economists have a new tool to price the effect of pollution. By comparing the amount of trash on a beach (or the cleanliness of its water) with the likelihood that people will go somewhere else, they can produce a dollar value for the effect of pollution. This allows communities to make decisions on whether or not to clean it up. This has been used to calculate the cost of littered beaches in California, algal blooms in Lake Erie, and the 2010 Deepwater Horizon spill on Florida’s tourism industry. The latter cost between $0.25 billion and $0.33 billion. Via The Conversation
The Chinese government invested heavily in irrigation projects on the North China Plain, the most populous region in that nation. Irrigation, however, exposes water to evaporation, increasing humidity and making it more difficult for residents to work and sleep. When humidity is close to 100%, even a healthy person may not be able to survive for more than six hours in 35° C temperatures. Under business-as-usual scenarios for greenhouse gas emissions, conditions will cross that threshold several times from 2070 and 2100, with irrigation adding half a degree to the perceived temperature. This threatens both farming and the lives of the 400 million inhabitants in the region, including Shanghai and Beijing. Via Phys.org
Energy and Power
If you live in a city, you might notice how much unused space there is on landfill sites, along the edges of freeways, flood-prone areas and warehouse roofs. If these areas were fitted with solar panels, cities could be self-powering rather than relying on rural solar installations, which consume farmland. These otherwise underused spaces could even generate an economic return. For example, the Fremantle in Western Australia is considering a proposal to use a former landfill site for a large-scale solar farm. Via Phys.org