【推荐1】Being highly connected to a strong social network has its benefits. Now a new study is showing the same goes for trees, thanks to their underground neighbors. The study is the first to show that the growth of adult trees is linked to their participation in fungal (真菌) networks living in the forest soil. Though past research has focused on young trees, these findings give new insight into the importance of fungal networks to older trees — which are more environmentally beneficial for functions like capturing carbon.

“Large trees make up the main part of the forest, so they drive what the forest is doing,” said researcher Joseph Birch, who led the study. When they live in the forest soil, fungal networks act as a sort of highway, allowing water, nutrients and compounds to flow back and forth among the trees. The network also helps nutrients flow to resource-limited trees like family units that support one another in times of stress.

Cores taken from 350 Douglas firs (花旗松) showed that annual tree ring growth was related to the extent of fungal connections a tree had with other trees. They had much higher growth than those that had only a few connections. The research also showed that trees with more connections to many unique fungi had much greater growth than those with only one or two connections. “If you have this network that is helping trees grow faster, that helps capture more carbon year after year. These networks may help trees grow more steadily even as conditions become more stressful, and could even help protect them against death.” said Birch.

Birch hopes his findings lead to further studies in different kinds of forests in other geographical areas, because it’s likely that the connections among trees change from year to year. He said, “Knowing whether fungal networks are operating the same way in other tree species could inform how we reforest areas after harvesting them, and inform how we plant trees to preserve these networks.”

【推荐2】If you do not use your arms or your legs for some time, they become weak; when you start using again, they slowly become strong again. Everybody knows this, and nobody would think of questioning the fact.    1     When someone says that he has a good memory, he really means that he keeps his memory in practice by exercising it regularly, either consciously or unconsciously. When someone else says that his memory is poor, he really means that he does not give it enough opportunity to become   strong.    2    One of them exercises his arms and legs by playing tennis, while the other sits in a chair or a   motor car all day.

If a friend complains that his arms are weak, we know that it is his own fault.     3    , many of us think that his parents are to blame, or that he is just unlucky, and few of us realize that it is just as much his own fault as if it was his arms or legs that were weak. Not all of us can become extremely strong or extremely clever; but all of us can, if we have ordinary bodies and brains, improve our strength and our memory by the same means––practice.

Have you ever noticed that people who cannot read or write usually have better memories than those who can?       4    Of course, because those who cannot read or write have to remember things: they cannot write them down in a little notebook. They have to remember dates, time and prices, names, songs and stories; so their memory is the whole time being exercised.

    5    , learn from the poor: practice remembering.

【推荐3】We certainly look different. The most obvious differences between boys and girls are our bodies, inside and out. For example, can men have babies? Can women grow beards?     1    

In the 1800s, scientists developed a theory called craniology (头骨学), which said that intelligence could be measured by skull size. Men have bigger skulls than women. So men must be smarter, people thought.     2     No one encouraged them to go on in school. Some doctors even said women who went to college would no longer be able to have children! Of course, now we know these beliefs aren’t true.

In the 1950s, psychologists gave girls and boys science tests to see if they could tell who was smarter. On average, the girls did worse than the boys.     3     But is this really true? Instead of measuring natural ability, maybe the tests revealed something about the conditions under which children were being taught. Parents and teachers didn't expect girls to do well in math or science，and so they didn’t encourage them. In class, teachers focused their attention on boys.     4    

As scientists continue to investigate, they have discovered that boys do seem to be better than girls at something called spatial rotation (空间转动）. Girls，on the other hand, do better on some tests of vocabulary and language. Why?     5     They often give girls dolls to play with, while they more frequently give boys blocks. Playing with blocks helps children develop spatial skills. So without meaning to, adults might be helping boys develop better spatial skills. And maybe they talk to girls more, which helps girls with those vocabulary words.

【推荐1】By the end of the century, if not sooner, the world’s oceans will be bluer and greener due to a warming climate, according to a new study.

At the heart of the phenomenon lie tiny marine microorganisms (海洋微生物) called phytoplankton, which create colourful patterns at the ocean surface. Ocean colour varies from green to blue, depending on the type and concentration of phytoplankton. Climate change will fuel the growth of phytoplankton in some areas, while reducing it in other spots, leading to changes in the ocean’s appearance.

Phytoplankton live at the ocean surface, where they pull carbon dioxide into the ocean while giving off oxygen. When these organisms die, they bury carbon in the deep ocean, an important process that helps to regulate the global climate. But phytoplankton are vulnerable to the ocean’s warming trend, which can easily affect phytoplankton growth.

Stephanie Dutkiewicz, a scientist in MIT’s Center for Global Change Science, built a climate model that projects changes to the oceans throughout the century. The model projects that currently blue areas with little phytoplankton could become even bluer. But in some waters, such as those of the Arctic, a warming will make conditions riper for phytoplankton, and these areas will turn greener.

And why does that matter? Phytoplankton are the base of the food web. If certain kinds begin to disappear from the ocean, Dutkiewicz said, “it will change the type of fish that will be able to survive.” Those kinds of changes could affect the food chain.

Whatever colour changes the ocean experiences in the coming decades will probably be too gradual and unnoticeable, but they could mean significant changes. Dutkiewicz said, “The change in the colour of the ocean will be one of the early warning signals that we really have changed our planet.”