RC -----Coral Reef

一战740

Can gougou verify this?

"The scale of damage to Jamaican reefs isenormous," Dr. Hughes said in the article, adding that there was "anurgent need" to stop overfishing around Jamaica. Steps to Combat Problem.
Dr.Hughes said that between surveys of the 1970's and the 1990's, overall coralcover in the waters that were examined declined to a mean of 3 percent from 52percent. "The classic zonation patterns of Jamaican reefs no longerexist," he wrote.
Thecatastrophic decline was caused by a chain of events that began with humans,Dr. Hughes wrote. Heavy fishing around Jamaica over the past 30 to 40 years hasremoved virtually all large predatory species, like sharks, snappers andgroupers, and has sharply reduced the size of herbivores, like parrot fish andsurgeon fish.
Asstocks declined, the ranks of a sea urchin known as Diadema antillarumexploded, its fish predators gone. The sea urchin, a bottom feeder with longspines that looks like a pincushion, ate the large colonial algae that grew onand around the reefs. But in 1983 disease virtually wiped out the urchin. Thelarge algae went uneaten, its urchin predators gone and the schools ofherbivorous fish wobbly.
Thecoral reefs might have endured had it not been for Hurricane Allen in 1980 andHurricane Gilbert in 1988. Coral and algae both took a beating. But in eachcase the algae fully recovered in a few weeks, crowding out the possibility ofnew corals.
Rebuilding the reefs will take far longer"than the two to three decades it has taken to destroy them," Dr.Hughes wrote. He warned that prospects for recovery were grim "unlessaction is taken immediately."

ccb

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glorialan0116

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jinchen0812

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lalalyouyou

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lalalyouyou

这篇的逻辑好像和JJ的不一样，但是感觉这篇更靠谱呢

remainyoung

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啊喂我是蚊子

lalalyouyou 发表于 2018-9-2 09:11
这篇的逻辑好像和JJ的不一样，但是感觉这篇更靠谱呢

感觉差不多 就是从文章中看出“海胆是帮助coral reef生存下来”这个点有点难，所以总的来说 algae海藻和coral珊瑚是不共存的，对吗？

goingsherry

啊喂我是蚊子 发表于 2018-9-2 11:20
感觉差不多 就是从文章中看出“海胆是帮助coral reef生存下来”这个点有点难，所以总的来说 algae海藻和c ...

同意！               

seleneli

BG info：
珊瑚礁是脆弱的，气候变化、过度捕捞鱼类、自然灾害等原因都会对其造成破坏。珊瑚礁受到破坏后，便会由珊瑚虫幼虫进行修复，它们会形成新的珊瑚来对礁群进行弥补。珊瑚虫，在幼体时期选择“定居地”时，有着明显的偏向性——它们更喜欢到富有珊瑚礁鱼群的健康礁体上安家落户，而不是选择有过多海藻的地方。这种选择和草食性鱼类有着莫大的联系：完整的鱼类群落有助于平衡海藻数量，帮助礁体恢复，但某些海藻会排斥鱼类和珊瑚幼体，促使珊瑚礁退化。
对珊瑚礁的生长和保持来说，海藻是一种负影响因素，在正常情况下，礁群鱼类和珊瑚虫所代表的正影响因素是能保持优势的，但由于目前过度捕捞鱼群的现象十分严重，对珊瑚虫有害的海藻在缺乏草食性鱼类的情况下大量繁殖，珊瑚虫以及新一代幼鱼因而无法在该区域“定居”。这些现象将导致被破坏的珊瑚礁无法及时被珊瑚虫弥补，最后使整个礁群得到毁灭性打击。