33 Plankton浮游生物. / plж `plжktэn/
Scattered through the seas of the world are billions of tons of small plants and animals called plankton. Most of these plants and animals are too small for the human eye to see. They drift about lazily with the currents, providing a basic food for many larger animals.
Plankton has been described as the equivalent of the grasses that grow on the dry land continents, and the comparison is an appropriate one. In potential food value, however, plankton far outweighs that of the land grasses. One scientist has estimated that while grasses of the world produce about 49 billion tons of valuable carbohydrates each year, the seas plankton generates more than twice as much.
Despite its enormous food potential, little effect was made until recently to farm plankton as we farm grasses on land. Now marine scientists have at last begun to study this possibility, especially as the seas resources loom even more important as a means of feeding an expanding world population.
No one yet has seriously suggested that plankton-burgers may soon become popular around the world. As a possible farmed supplementary food source, however, plankton is gaining considerable interest among marine scientists.
One type of plankton that seems to have great harvest possibilities is a tiny shrimp-like creature called krill. Growing to two or three inches long, krill provides the major food for the great blue whale, the largest animal to ever inhabit the Earth. Realizing that this whale may grow to 100 feet and weigh 150 tons at maturity, it is not surprising that each one devours more than one ton of krill daily.
国际英语资讯:Egypts Sisi urges faster railway development to avoid deadly crashes
体坛英语资讯:Frenchman Bosse crowned mens 800m world champion (updated)
国际英语资讯:ASEAN foreign ministers commend Chinas regional role
体坛英语资讯:Olympic champion Kipruto claims 3000m steeplechase title at worlds
国际英语资讯:Britain denies agreeing to multi-billion under Brexit divorce bill
体坛英语资讯:Gong wins Chinas first gold medal, surprise victories for Warholm and Francis
国际英语资讯:UN chief urges Venezuelans to ease tensions, engage in negotiations
国际英语资讯:Iran adopts economic diplomacy as key foreign policy
国际英语资讯:China continues to see slowdown in luxury goods spending: report
国际英语资讯:Irans parliament takes steps to counter U.S. pressures
国际英语资讯:Chinas mobile apps exceed 4.02 mln
国际英语资讯:Venezuela rejects Trumps threats of violence
国际英语资讯:1 in 4 U.S. voters think Trumps dealings with Russia illegal during campaign: poll
国际英语资讯:Investigation reopens against Brazilian former president Lula
国际英语资讯:U.S. federal court rules in favor of Chinese businesswoman beaten by border agent in 2004
国际英语资讯:Sisi reiterates need for Qatar to respond to Arab quartets concerns
国际英语资讯:Chinas Dalian Wanda Australian operations not for sale: Aussie chief
国际英语资讯:Syria urges UN to dissolve U.S.-led coalition over crimes against civilians
国际英语资讯:France urges DRRK to comply with obligations, prevent further tensions
国际英语资讯:Poverty, illiteracy responsible for security challenges in N Nigeria: governor
国际英语资讯:Singapore launches Southeast Asias largest drone light show at National Day Parade
国际英语资讯:Spotlight: Trump intensifies attacks at McConnell over health care failure
国际英语资讯:Spotlight: Chinese Americans divided on Trumps new immigration bill
国际英语资讯:Time for de-escalation, lowering tensions over Korean Peninsula: UN
国际英语资讯:Syrian army captures last IS stronghold in Homs province
国际英语资讯:German startups expect better business in next six months: Study
国际英语资讯:Economic reforms in Serbia reflected in booming trade with Netherlands: Dutch FM
国际英语资讯:Slovenian presidential election set for Oct. 22
国际英语资讯:Commentary: Britain takes step to protect personal data in digital era
国际英语资讯:Canada to send 20 more police officers to Iraq
| 不限 |
| 英语教案 |
| 英语课件 |
| 英语试题 |
| 不限 |
| 不限 |
| 上册 |
| 下册 |
| 不限 |