新東方優美背誦短文50篇 Unit33:Plankton浮游生物

33 Plankton浮游生物.

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 sea’s 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 sea’s 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.

浮游生物數十億噸的被稱為"浮游生物"的小動物、植物散布在世界的海洋中。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，浮游生物遠勝于草類。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，而海洋里的浮游生物每年生產的碳水化合物多于此數的兩倍。盡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獲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。