男女羞羞视频在线观看,国产精品黄色免费,麻豆91在线视频,美女被羞羞免费软件下载,国产的一级片,亚洲熟色妇,天天操夜夜摸,一区二区三区在线电影
English 中文網 漫畫網 愛新聞iNews 翻譯論壇
中國網站品牌欄目(頻道)
當前位置: Language Tips > Normal Speed News VOA常速

Sea life color codes food to evade danger

[ 2012-09-11 14:56] 來源:中國日報網     字號 [] [] []  
免費訂閱30天China Daily雙語新聞手機報:移動用戶編輯短信CD至106580009009

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010-84883631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。
 

關注和訂閱

人氣排行

翻譯服務

中國日報網翻譯工作室

我們提供:媒體、文化、財經法律等專業領域的中英互譯服務
電話:010-84883468
郵件:translate@chinadaily.com.cn
 
 
主站蜘蛛池模板: 凤台县| 奈曼旗| 维西| 沅江市| 林芝县| 敦煌市| 绥宁县| 洪江市| 闸北区| 林周县| 喜德县| 余江县| 凉城县| 翼城县| 沅陵县| 扶绥县| 柞水县| 法库县| 建平县| 互助| 紫阳县| 社旗县| 上犹县| 苏尼特左旗| 安岳县| 江北区| 华阴市| 上虞市| 景泰县| 清流县| 巧家县| 称多县| 晋中市| 泰和县| 宁德市| 都昌县| 永吉县| 绵竹市| 汝州市| 安徽省| 塔河县| 桃园市| 泸定县| 惠安县| 托克托县| 玉门市| 额济纳旗| 美姑县| 大洼县| 浮山县| 宁安市| 奉新县| 高唐县| 南充市| 色达县| 佛冈县| 曲松县| 大理市| 睢宁县| 阿克| 勐海县| 宁化县| 称多县| 峡江县| 措勤县| 昭平县| 许昌县| 乡宁县| 舞钢市| 和静县| 高要市| 精河县| 呼和浩特市| 渝北区| 庄河市| 延庆县| 灵武市| 剑川县| 宣城市| 厦门市| 合川市| 盐城市|