久久亚洲国产成人影院-久久亚洲国产的中文-久久亚洲国产高清-久久亚洲国产精品-亚洲图片偷拍自拍-亚洲图色视频

 
 
 

Sea life color codes food to evade danger

中國日報網 2012-09-11 14:56

 

Get Flash Player

Download

The ocean glows with undersea life which makes its own light.

These animals living on the ocean floor, beyond the reach of sunlight, have evolved this bioluminescence for camouflage, to find mates or to repel or confuse predators.

They also have a sort of color vision which combines sensitivity to blue and ultraviolet light. Their detection of these shorter wavelengths may provide them a way to ensure they grab food, not poison.

Two new studies published this week in Experimental Biology illuminate the scene on the sea floor.

Duke University biologist Sonke Johnsen was among a crew of scientists on a submersible vehicle that explored the ocean bottom at three sites near the Bahamas.

“Our original guess was that actually the whole sea floor might have a dim glow from bacteria," Johnsen says. "There are a number of bacteria that glow continually as they are breaking down dead animals and things of that sort.”

But that wasn’t the case. Using the vehicle’s robotic arm, they gently tapped the coral, crabs and anything else that moved to see which seabed creatures emitted light.

Only 20 percent did, compared to 90 percent of the species that populate the open ocean higher in the water column.

Johnsen, who led the bioluminescence study, says the plankton produced a different color from the animals that ate them.

“It is very, very blue. It’s like a blue LED. It’s just this beautiful, beautiful pure blue. Much of the light from the animals on the sea floor was green, or at least greener, and so you end up with this world where you have little blue flashes of light in the water and then green light whenever anything is touched on the bottom.”

For the second study, researchers collected species and brought them to the surface. Frank placed tiny electrodes on their eyes, and made a curious finding.

“That there are several species of deep sea crab that have both a blue and an ultraviolet visual pigment,” says Nova Southeastern University biologist Tamara Frank, who led the study.

Most creatures in the deep sea have evolved to detect only blue light, not the shorter ultraviolet waves that don’t penetrate to the sea floor.

Johnsen, a co-author of this study, says crab behavior provided a clue about why they could see both.

“And as they touched these plankton and feed on them, those glow blue. But as they touch the coral they are standing on, that glows green.”

“What we hypothesize is that they are picking off the blue stuff, which they like to eat," says Frank, "and when the blue stuff hits the green stuff with that ultraviolet visual pigment, they can tell the difference between the blue and the green and therefore pick off what they like to eat versus what they don’t like to eat.”

Johnsen adds, “And so what our guess is - but we are not certain of this yet - is that they are actually using their color vision. In other words, blue comes from the water, blue is tasty. Green is what I am standing on. I don’t want that. It’s toxic.”

Understanding how deep sea animals see has led to a greater understanding of deep space. An orbiting x-ray telescope was inspired by the wide-angle vision of lobsters.

bioluminescence: 生物體發光,生物熒光

相關閱讀

'Silent Spring' turns fifty(視頻)

Words and their stories: Hold your horses!

Driving with GPS can be difficult to navigate

Teens help revive California nature(視頻)

(來源:VOA 編輯:Julie)

 
中國日報網英語點津版權說明:凡注明來源為“中國日報網英語點津:XXX(署名)”的原創作品,除與中國日報網簽署英語點津內容授權協議的網站外,其他任何網站或單位未經允許不得非法盜鏈、轉載和使用,違者必究。如需使用,請與010-84883561聯系;凡本網注明“來源:XXX(非英語點津)”的作品,均轉載自其它媒體,目的在于傳播更多信息,其他媒體如需轉載,請與稿件來源方聯系,如產生任何問題與本網無關;本網所發布的歌曲、電影片段,版權歸原作者所有,僅供學習與研究,如果侵權,請提供版權證明,以便盡快刪除。

中國日報網雙語新聞

掃描左側二維碼

添加Chinadaily_Mobile
你想看的我們這兒都有!

中國日報雙語手機報

點擊左側圖標查看訂閱方式

中國首份雙語手機報
學英語看資訊一個都不能少!

關注和訂閱

本文相關閱讀
人氣排行
熱搜詞
 
 
精華欄目
 

閱讀

詞匯

視聽

翻譯

口語

合作

 

關于我們 | 聯系方式 | 招聘信息

Copyright by chinadaily.com.cn. All rights reserved. None of this material may be used for any commercial or public use. Reproduction in whole or in part without permission is prohibited. 版權聲明:本網站所刊登的中國日報網英語點津內容,版權屬中國日報網所有,未經協議授權,禁止下載使用。 歡迎愿意與本網站合作的單位或個人與我們聯系。

電話:8610-84883645

傳真:8610-84883500

Email: [email protected]

主站蜘蛛池模板: 99久久精品免费看国产免费 | 精品免费久久久久欧美亚一区 | 国产精品高清视亚洲一区二区 | 亚洲在线偷拍自拍 | 日韩欧国产精品一区综合无码 | 91九色偷拍| 毛片1毛片2毛片3毛片4 | 99精品国产免费久久国语 | 国产成人免费午夜在线观看 | 又黄又免费的网站 | 国产成人18黄网站在线观看网站 | 国产精品久久久久影院色老大 | 亚洲在线影院 | 99视频网站 | 亚洲一区二区三区精品国产 | 日本乱理伦中文三区 | 美女互操| 成人国产第一区在线观看 | 欧美.亚洲.日本一区二区三区 | 成人网18免费软件 | 精品视频一区二区三区四区 | 久久国产精品久久精品国产 | 国产精品久久在线 | 成人久久18免费网站 | 色一情一乱一乱91av | 亚洲伊人久久综合影院2021 | 色视频在线观看免费 | 91精品一区二区三区在线播放 | 亚洲人成网站在线在线 | a级毛片毛片免费观看永久 a级毛片毛片免费很很综合 | 免费一级毛片免费播放 | 欧美 亚洲 中文字幕 | 久久精品国产亚洲a | 9191精品国产观看 | a级毛片在线视频免费观看 a级免费 | 免费真实播放国产乱子伦 | 国内精品99 | 国内自拍小视频 | 69成人做爰视频69 | 一级做a爱片特黄在线观看 一级做a爱片特黄在线观看免费看 | 日本黄色大片在线播放视频免费观看 |