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陳蕙雅思教材 - 雅思閱讀精選 (Plankton)瀏覽數:44次
Plankton Scattered through theseas of the world are billions of tons of small plants and animals calledplankton. Most of these plants andanimals are too small for the humaneye to see. They drift about lazily with the currents, providing a basic food for many largeranimals. Plankton has beendescribed as the equivalent of thegrasses that grow on the dryland continents, and the comparisonis an appropriate one. In potential food value,however, plankton far outweighs that of the land grasses. One scientisthas estimated that while grasses of the world produce about 49 billiontons of valuable carbohydrateseach year, the sea's plankton generatesmore than twice as much. Despite its enormous foodpotential, little effect was made until recently to farm plankton as wefarm grasses on land. Now marine scientists have at last begun to study this possibility,especially as the sea's resources loom even more important as a means of feeding anexpanding world population. No one yet has seriouslysuggested that "planktonburgers" 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 shrimplike creaturecalled krill. Growing to two orthree inches long, krill provide the majorfood for the great blue whale, the largest animal ever inhabit the Earth.Realizing that this whale may grow to 100 feet and weigh 150tons at maturity, it is not surprisingthat each one devours more than one tonof krill daily. 浮游生物 數十億噸的被稱為"浮游生物"的小動物、植物散佈在世界的海洋中。 這些小 的動、植物大多太小而難以被人眼看到。 它們隨波逐流，為許多較大的動物提供了基本的 食物。 浮游生物曾被描述為生長在大陸陸地上的各種草類的海洋對應物。 這種比喻是恰當 的。 然而就潛在的食物價值而言，浮游生物遠勝於草類。 一位科學家曾經估計，世界上的 草類每年生產大約 490 億噸有用的碳水化合物，而海洋裡的浮游生物每年生產的碳水化合物 多於此數的兩倍。 儘管浮游生物具備巨大的食物潛能，但直到最近人們還很少象種植草類 那樣付出努力養殖浮游生物。 現在，海洋科學家們至少已開始研究這種可能性。 全球人口 不斷擴張，海洋資源作為食品的重要性日益突出。 現在還沒有人認真說過"浮游生物漢堡"會很快在世界上流行起來。 然而，作為一種可能養殖的補充性食物資源，浮游生物正引起 了海洋科學家們相當大的興趣。 一種似乎具有很大收穫可能性的微小的蝦狀浮游生物被稱 為鱗蝦。 鱗蝦長至 2～3 英寸長時即成為地球上曾居住過的最大動物--藍鯨的主要食物。 成 熟的藍鯨可以達到 100 英尺長，150 噸重，所以每頭鯨每天吞食 1 噸多的鱗蝦一點也不讓人 吃驚。
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