考研英语作文：提取牡蛎 Raising Oysters_英语作文范文
在我们平凡的日常里，大家总少不了接触作文吧，通过作文可以把我们那些零零散散的'思想，聚集在一块。如何写一篇有思想、有文采的作文呢？以下是小编为大家整理的考研英语作文：提取牡蛎 Raising Oysters_英语作文范文，供大家参考借鉴，希望可以帮助到有需要的朋友。
in the oysters were raised in much the same way as dirt farmers raised tomatoes- by transplanting them. first, farmers selected the oyster bed, cleared the bottom of old shells and other debris, then scattered clean shells about. net, they "planted" fertilized oyster eggs, which within two or three weeks hatched into larvae. the larvae drifted until they attached themselves to the clean shells on the bottom. there they remained and in time grew into baby oysters called seed or spat. the spat grew larger by drawing in seawater from which they derived microscopic particles of food. before long, farmers gathered the baby oysters, transplanted them once more into another body of water to fatten them up.
until recently the supply of wild oysters and those crudely farmed were more than enough to satisfy people＇s needs. but today the delectable seafood is no longer available in abundance. the problem has become so serious that some oyster beds have vanished entirely.
fortunately, as far back as the early 1900＇s marine biologists realized that if new measures were not taken, oysters would become etinct or at best a luury food. so they set up well-equipped hatcheries and went to work. but they did not have the proper equipment or the skill to handle the eggs. they did not know when, what, and how to feed the larvae. and they knew little about the predators that attack and eat baby oysters by the millions. they failed, but they doggedly kept at it. finally, in the 1940＇s a significant breakthrough was made.
the marine biologists discovered that by raising the temperature of the water, they could induce oysters to spawn not only in the summer but also in the fall, winter, and spring. later they developed a technique for feeding the larvae and rearing them to spat. going still further, they succeeded in breeding new strains that were resistant to diseases, grew faster and larger, and flourished in water of different salinities and temperatures. in addition, the cultivated oysters tasted better!
【考研英语作文：提取牡蛎 Raising Oysters_英语作文】相关文章：
养宠物的英语作文：Pet Raising08-13
考研英语作文06-15
英语考研作文02-15
考研英语作文06-15
考研英语作文08-24