1 . Bad news for banana lovers: A fungus (真菌) that’s particularly good at killing the fruit has finally reached Latin America — a major supplier of the world’s bananas.
Recently, officials in Colombia announced a national emergency after confirming the presence of this fatal fungus, known as Fusarium oxysporum Tropical Race 4 (TR4), in the country. This is the first time the fungus has been found in Latin America. However, the fungus isn’t new. Over the past years, it has been destroying banana plantations in Asia, Australia and East Africa.
Although this fungus isn’t harmful to humans, it is a “serious threat” to banana production. The fungus attacks the plants’ roots and blocks their vascular (维管的) system — the network used to transport water and nutrients (营养物) and finally kills the plants. Once the fungus finds its way into soil, it can’t be treated with fungicides, and it’s very difficult to remove.
What’s more, the fungus attacks the most commonly exported banana — the Cavendish banana. “For Western countries, the vast majority of the bananas we eat are from the same Cavendish subgroup,” said Nicolas Roux, a senior scientist.
Sarah Gurr, Exeter University’s chair in food security, continued to explained to Wired, “Cavendish bananas are in effect clones of their parents. So the similarity in their genes makes them easy targets of the disease. Actually, we are likely to lose the Cavendish banana.”
Officials reported that the TR4 fungus was found in a l75-hectare area in the La Guajira region of northern Colombia. The country has separated affected areas and destroyed some of them in an effort to fight the fungus. A number of ideas have come up to help save the Cavendish banana, including genetically engineering plants that will not be affected by TR4.
1. Why did Colombia announce a national emergency?| A．Because the TR4 fungus stops banana trees producing fruits. |
| B．Because there was TR4 fungus in Colombia. |
| C．Because a fearful fungus was spreading quickly. |
| D．Because Colombia had no bananas to transport to Europe. |
| A．It causes the death of banana plants. | B．It is dangerous for human beings. |
| C．It competes with banana trees for water. | D．It exists in the air to attack plants. |
| A．Their importance in global fruit supply. | B．Their poor ability to gain nutrients. |
| C．Their lack of genetic diversity. | D．Their wide planting in Latin America. |
| A．Bananas crisis in Latin America | B．The best bananas in the world |
| C．Fungus harms plants | D．Banana-killing fungus reached Latin America |
2 . Sargassum is a kind of floating seaweed (海草) that has been growing in size every year. It looks pretty in the ocean. However, sargassum can almost completely block out sunlight. Important kinds of seagrass suffer when light is blocked by seaweed. As sargassum piles up on beaches, it makes it hard for mother sea turtles to lay eggs, and nearly impossible for baby turtles to return to the sea.
So much sargassum piles up on beaches, and it breaks down slowly, giving out a bad smell like rotten eggs. “Even when governments clear the seaweed from beaches, they face problems of getting rid of it. Heavy machines can put turtle nests in danger. Some people have thought about using sargassum as a fertilizer (肥料), but it contains harmful heavy metals. So far, removing these harmful metal s costs too much to make it worth doing,” said the scientist Steven Kelley.
Sargassum grows faster in warming oceans, so climate change is definitely part of the problem. But scientists believe the unusual growth of the seawood is also caused by huge quantities of fertilizers washed into the ocean from farmlands.
Scientists and students are working hard to figure out how to deal with sargassum. Some suggest using sargassum as a building material, or possibly a fuel. One unusual solution is to drop it deep in the sea by using robots. Sargassum takes in huge amounts of carbon dioxide (二氧化碳) as it grows. Removing carbon dioxide from the atmosphere is one important part of fighting the climate crisis. Sargassum could deal with this carbon dioxide in the deep ocean. Scientists are still testing this idea to see if it will work.
For now, scientists say the quickest solution is to stop filling the ocean with fertilizers. It is wise for farmers to change the way they farm. Moreover, the seaweed’s growth can have serious effects on islands that depend heavily on tourism and fishing. Island communities play a role in cleaning up the seaweed and promoting responsible tourism. At the same time, officials have to work towards changing policies to solve the issues.
1. What can we know about sargassum according to the first paragraph?| A．It affects the ecosystem negatively. |
| B．It adds to the variety of life in the ocean. |
| C．It causes a shortage of food for sea animals. |
| D．It creates a good living environment for seagrass. |
| A．Reusing metal s from sargassum is a wise choice. |
| B．Fertilizers can help sargarrum break down quickly. |
| C．Dealing with sargassum safely is challenging work. |
| D．Practical ways have been developed to remove sargassum. |
| A．By spreading sargassum widely to increase sunlight. |
| B．By changing sargassum into a renewable energy source. |
| C．By employing sargassum as a cleaner for ocean pollution. |
| D．By making use of sargassum’s ability to absorb carbon dioxide. |
| A．Public attempts to recycle seaside sargassum. |
| B．The change in sargassum’s living environment. |
| C．Challenges and approaches concerning sargassum. |
| D．The influence of sargassum’s growth on climate change. |
