4 . Noise pollution has a long-term effect on tree populations that may persist even after the sources of noise are removed, according to research published Wednesday.

Man-made noise from industry and the building of infrastructure such as roads and pipelines has increased greatly since the middle of last century. While previous research has documented the short-term effect noise has on tree populations as it scares off pollinators (传粉者) such as insects and animals, few studies have covered the long-term effect.

Researchers in the United States looked at tree populations in New Mexico that had been “hearing”a high level of man-made noise for 15 years. They found 75 percent fewer pinyon pine seedlings (矮松苗) in noisy places than quiet ones.

Then they looked at other places in New Mexico, where sources of noise had recently been added and then removed, and examined how populations recovered. The team assumed that populations of the trees — in this case pinyon seedlings — would recover as the pollinators would return to the places once the noise had disappeared. Instead, they found a long-term drop in seedling numbers as the birds refused to revisit the places.

“The effects of human noise pollution are growing into these woodland communities,” said Clinton Francis, lead researcher from California Polytechnic State University. “What we’re seeing is that removal of the noise doesn’t necessarily immediately result in a recovery of ecological function.”

Jennifer Phillips, co-author of the research, said the findings showed how the effect of noise pollution could put pollinators off even after the noise is removed. “Animals like the birds that are sensitive to noise learn to avoid particular areas.” said Phillips. “It may take time for animals to come back to pollinate trees in these previously noisy areas, and we don’t know how long that might take.”

As governments continue to face growing evidence of the damage to nature caused by urbanization (城市化), Phillips held that the influence of noise pollution should also be factored into planning decisions.

7 . The effects of noise can reach organisms (生物体) without ears. Because of the way living things rely on each other, noise pollution may actually stop some forests from growing, a new study suggests. In a New Mexico woodland of pine trees, researchers found far fewer tree seedlings (小苗) in noisy sites than they did in quiet ones.

The study area is dotted with gas wells, some of which are quiet and some of which have compressors (压缩机) that create a constant noise. This allowed Jennifer Phillips, a behavioral ecologist at Texas A&M University-San Antonio and her colleagues to compare sites that were similar except for noise level. In areas that had been noisy for at least 15 years, the researchers found only about 13 pine seedlings, compared with 55 pine seedlings per hectare (公顷) in quiet areas.

The differences in plant growth were probably caused by changes in animal behavior, said Phillips. For example, noise might drive away certain pollinators (传粉昆虫) such as bees, bats and moths. In the case of pine trees, the problem was likely a lack of animals to disperse seeds. Pines depend on birds to carry their seeds away from the parent tree, and birds are known to avoid noise. The differences between the sites aren’t yet obvious to someone walking through them, said Sarah Termondt, a botanist (植物学家) with the U.S. Fish and Wildlife Service who helped conduct the study. That’s probably because pines are slow-growing, with most of the mature trees in such woodlands being over a century old.

The study raises questions about the future of the area. “If the noise stays there long term, are we going to lose this important ecosystem of the pine which supports so much wildlife?” said Phillips. The study was published today in the journal Proceedings of the Royal Society.

8 . The green movement is catching on in many pockets of the world. This is especially true in the construction industry. Today's buzz words, which include global warming and zero emissions（排放）, are causing everyday people to look for ways to reduce their carbon footprint. Purchasing an environmentally-friendly home is a good investment for those who care about their own health and the well-being of our planet. Based on this trend, entire districts, known as eco-communities, are being designed with the concept of green in mind. One of these communities is Dockside Green in the Canadian province of British Columbia. Its goal is to become the world's first zero-emission neighborhood.

Dockside Green is a mostly self-sufficient community along the harbor front of Victoria, the capital city of British Columbia. The community is home to around 2,500 people and it includes a variety of environmental features, some of which can't be found anywhere else.

The planners and builders of Dockside Green have the environment in mind with every choice they make. They ensure proper ventilation （通风） and guarantee residents clean air indoors. Building materials, such as paints and wood, are natural and green.

Energy efficiency is attached great importance to in eco-communities like Dockside Green. Not only do energy-efficient appliances reduce the environmental impact of heating, cooking and lighting, they also save residents money. Dockside Green claims that home owners use 55% less energy than the average Canadian.

Eco-communities also take the future into account by recycling waste and reducing carbon emissions. At Dockside Green, waste water is treated and reused on-site for flushing toilets, and a gas plant changes waste wood into a renewable form of gas for hot water systems, stoves and gas heaters. The community also reduces carbon emissions by using local suppliers for all their transport and maintenance（维修） needs, and residents are encouraged to join the community's car share program.

9 . Off the coast of Formentera, an island, lives seagrass that stretches 15 km. The seagrass, covering several kilometers, is made up of a single organism. The grasses are also long-lived, for tens or hundreds of thousands of years. Along with two other kinds of coastal ecosystem—mangrove swamps and tidal marshes—seagrass fields are particularly good at taking carbon dioxide from the air.

This role was highlighted in a report published on March 2nd by UNESCO, on “blue carbon” —the carbon stored by Earth’s oceanic and coastal ecosystems. In total around 3,300 million tons of carbon dioxide (about three-quarters of the world’s emissions in 2019) are locked away in the planet’s blue-carbon sinks. Research by Carlos Duarte, the report’s author and an ecologist, has shown that one hectare of seagrass can suck as much carbon dioxide each year as 15 hectares of rainforest.

One reason that blue-carbon ecosystems make such effective sinks is that underwater forests are thicker than the land-based woods. They can also trap floating pieces and organic matter, which settles on the sea floor and can double the amount of carbon stored away. They possess another advantage, too. Climate change is leading to more wildfires around the world. As forests burn, their carbon stocks are sent back into the atmosphere. Unlike forests on land, blue-carbon ecosystems do not burn.

Blue-carbon ecosystems may not be fired, but they remain affected by other sorts of disasters. In May 2020 cyclone Amphan destroyed 1,200 square kilometers of mangrove forests. A marine heatwave in Australian waters in 2010 and 2011 damaged around one third of the world’s largest seagrass field in Shark Bay. Mangrove forests can weaken or control waves and provide natural barriers to storm surges. Protecting and expanding them, then, appears to be a must.