1 . The Atlantic salmon (鲑鱼) of Scotland are hardy and determined animals. Each spring and summer, they return from the North Atlantic Ocean to lay eggs in Scotland’s shallow rivers,leaping up waterfalls and over barriers, pushing themselves upstream in enormous efforts. Some fail, and others succeed, but today they face yet another challenge.

During the mid-1980s, there were between eight and ten million salmon swimming around Scotland’s Atlantic coast; that number has now dropped sharply. There’s evidence of reducing the availability of the salmon’s prey (猎物) as climate change warms and acidifies oceans. New research suggests climate change is also bearing down on rivers, which is bad news for salmon.Adapted to life in cold water, salmon experience slow growth and population changes at high temperatures. Heat influences their health and reduces their resistance to disease.

“Now salmon are struggling to deal with the rising temperatures. There are recent records of 27°C in the upper reaches of the Dee catchment,” says Peter Cairns, director of an environmental charity. In 2018, Scotland recorded the lowest pole catch for salmon since records began. Evidence suggests that the degraded quality of river worsens the impact of our changing climate. “Atlantic salmon evolved using river systems in Scotland that were once way more forested and therefore shaded.” Yet Scotland is today one of the least wooded countries in Europe, with just 3 percent of its native woodland undamaged. Scientists have found that just 35percent of rivers in Scotland have enough tree cover for salmon survival.

A movement to get trees back on riverbanks is gathering pace. “Broad-leaf trees close tothe bank can reduce the light that enters the water,” explains fisheries scientist Anthony Hawkins. A new initiative called Riverwoods — led by the Scottish Wildlife Trust and supported by Scottish Water and several other government and regulatory bodies — aims to create a network of woodlands along Scotland’s riverbanks, and has already received a number of large funds.“Money is not the pressing business. River health is complex, but tree planting is one of the most basic things we can get started with right away,”says Cairns.

3 . Some scientists have traced the increase in earthquakes, especially in areas not known for the presence of fault lines or past seismic (地震的) activity, to human actions. The idea of humans causing earthquakes may seem strange at first. After all, you can run around your backyard and jump up and down as you want, and the ground isn’t going to start shaking. However, scientists have identified a variety of large scale human activities that can result in earthquakes.

Scientists have confirmed over 700 places where human activities have caused earthquakes over the last century. While many human-related earthquakes are mild and don’t cause much damage, some of them can be serious and dangerous. In fact, scientists believe human activity has caused earthquakes with magnitudes as high as 7.9 on the Richter scale.

Scientists believe most human-related earthquakes are the result of mining. As companies drill deeper and deeper below Earth’s surface to get natural resources, holes left behind can cause instability that leads to collapses that cause earthquakes. Another human activity leading to earthquakes is fracking (水力压裂) for oil and gas, including the high pressure waste water processing that usually goes with fracking. In this process, water, sand and chemicals are pressed underground under high pressure to break rocks to release natural resources.

Building large dams can also cause earthquakes. For example, about 80, 000 people died in China in 2008 as a result of a 7.9-magnitude earthquake caused by 320 million tons of water that had been collected in the Zipingpu Reservoir after a large dam was built over a known fault line.

These aren’t the only human activities that can result in earthquakes, though. Scientists point out that earthquakes can also be caused by other human activities, such as construction of skyscrapers and nuclear explosions.

4 . In recent years, lots of American companies have gotten behind a potential climate solution called carbon capture and storage, and the government has backed it with billions of dollars in tax preferences and direct investments. The idea is to trap planet-heating carbon dioxide from the smokestacks of factories and power plants and ship it to sites via thousands of miles of new pipelines. Communities nationwide are pushing back against these pipeline construction and underground sites, arguing they don’t want the pollution running through their land.

Now the U. S. Forest Service is proposing to change a rule to allow storing this carbon dioxide pollution under the country’s national forests and grasslands. “Authorizing carbon capture and storage on National Forest System (NFS) lands would support the Administration’s goal to reduce greenhouse gas emissions by 50 percent below the 2005 levels by 2030,” the proposed rule change says.

Some experts, like June Sekera, a research fellow with Boston University, question the timing of the proposed rule change, given community pushback across the country to pipelines planned on private land. Yet she says the Forest Service proposal to open up national parks for CO2 storage is “an end run around local towns and counties. And it’s a much simpler and way less expensive route.”

In an email, Scott Owen, press officer for the Forest Service, writes that the proposed rule change would allow the Forest Service to consider proposals for carbon capture and storage projects. He writes that any proposals must still pass through a secondary screening, adding, “The Forest Service has been ‘screening’ proposals for use of NFS lands for over 20 years as a means to be increasingly consistent in our processes and also be able to reject those uses that are inconsistent with the management of the public’s land. ” He notes the Forest Service currently does not have any carbon capture project proposals under consideration. The Forest Service has opened public comments on the proposed rule change until Jan. 2, 2024.

7 . A new international organization, ReShark, including partners from 15 countries and 44 aquariums, is challenging the shark statistics. According to National Geographic, ReShark’s goal is to release 500 endangered zebra sharks in Indonesian waters to increase a wild population that is on the edge of extinction. This is the first-ever attempt to reintroduce captive sharks into the wild.

Marine reintroductions present significant challenges due to the complexity and shortage of ocean life, as well as the difficulty in managing threats, according to National Geographic. Team ReShark understands that the reintroduction may go up in smoke. Unlike land animals that have been successfully reintroduced in the past, such as giant pandas in China, young sharks are more likely to suffer from diseases and be killed by other animals, and they struggle to find food on their own.

Sharks have a remarkable history as one of the oldest vertebrate species, surviving five mass extinctions over a period of 420 million years. They play an important role in marine ecosystems by influencing the ocean’s food chains. However, they are now facing the second-highest rate of disappearance. Research shows that more than 37 percent of the shark species are at risk of extinction due to overfishing, both legal and illegal. Sharks are hunted for their meat. Nearly 100 million sharks are killed by human hands each year, according to the organization Sentient Media.

Despite the alarming decline in shark populations globally, top shark scientists are hopeful that ReShark’s efforts will succeed. Given these challenges, Simon Fraser University ecologist Dulvy initially had some doubts about ReShark’s plans. However, after asking some questions, he was surprised by what the initiative could produce. “This initiative is different,” Dulvy explained. Similarly, Rima Jabado, Dulvy’s successor, recognized ReShark as a unique project that could provide a lifeline for endangered shark species. “It may provide an opportunity for species not to go extinct,” she said.

8 . From airplanes to apartments, most spaces are now designed with sound-absorbing materials that help decrease various sounds of everyday life. But most of the sound-absorbing materials that can cancel out human voices, traffic noise and music are made from plastic foams (泡沫) that aren’t easily recycled or degraded. Now, researchers reporting in ACS Sustainable Chemistry & Engineering have created a biodegradable film (薄膜) obtained from seaweed, which effectively absorbs sounds in this range.

Controlling and optimizing the way sound moves throughout a room is the key to creating functional spaces. Foam sound-absorbing panels are a common solution, and they come in a variety of materials and thicknesses tailored to specific sound requirements. Most of these foams, however, are made from a type of plastic material and other chemical substances that are obtained from natural oil or petrol. To avoid petrochemicals, researchers have explored more renewable sources and biodegradable sound-absorbing alternatives. But many current options are made from plant fibers that don’t effectively decrease noises in the most useful range of sound frequencies, or they are too thick or difficult to produce. So, Chindam’s team wanted to develop a biodegradable material from a plant, which would be simple to produce and could absorb a range of sounds.

The team created films of agar (琼脂), a material that comes from seaweed, along with other additives developed from plants and varied the thickness of the films. After running the materials through a battery of tests, the researchers measured how well the films reduced sound across a range of frequencies. To do this, the team created a sound tube in which a speaker is placed at one end, and the test film is fitted over the other end. Microphones in the middle of the tube measured the amount of sound sent by the speaker and the amount of sound reflected off the film. These experiments showed that the films with many small holes made with the highest concentrations of agar had the greatest sound-absorbing qualities and performed similarly to traditional sound-absorbing foams. The researchers plan to explore ways to change the agar films to give them other desirable properties, such as flame resistance, and will explore other biologically obtained film materials.