火ひ体たい虫むし属ぞく

火ひ体からだ虫ちゅう Pyrosoma
在ざい东帝汶的てき阿おもね陶すえ罗岛发现的てき一个年轻的火体虫群体 （长约1厘りん米まい）。
科學かがく分類ぶんるい

火ひ体からだ虫ちゅう（學名がくめい：Pyrosomes）是これ火ひ体たい虫むし目め火ひ体たい虫むし科か火ひ体たい虫むし科か之これ下か唯一ゆいいつ的てき一いち個こ属ぞく火ひ体たい虫むし属ぞく（Pyrosoma）物種ものだね的てき通稱つうしょう，均ひとし為ため自由じゆう浮动的てき被ひ囊动物ぶつ群落ぐんらく。通常つうじょう栖息せいそく在ざい公海こうかい上うえ层的温暖おんだん海水かいすい中ちゅう，尽つき管かん有ゆう些可能かのう在ざい更さら深ふか处被发现。 火ひ体たい虫むし群ぐん体からだ是ぜ由よし几百到几千个被称为“个虫”（zooid）的てき个体组成的てき圆筒形がた或ある锥形群ぐん体たい，其尺寸しゃくすん范围从小于一厘米到几米长。他た们通常つうじょう被ひ称しょう为“海うみ泡あわ菜さい”。

每まい个个虫ちゅう只ただ有ゆう几毫米まい大小だいしょう，但ただし是ぜ嵌入かんにゅう了りょう一个加入了所有个体的共同的凝胶状的外衣。每まい个个虫むし都と向むこう“管かん”状じょう群ぐん体からだ的てき内部ないぶ和わ外部がいぶ开放，从外部ぶ吸入きゅうにゅう海水かいすい到いた其内部ないぶ的てき过滤网被称しょう为“鳃笼”，用よう于提取と微小びしょう的てき植物しょくぶつ细胞上じょう的てき供きょう给物，然しか后きさき将はた过滤后きさき的てき水みず排はい到いた群ぐん体からだ的てき圆筒内ない。群ぐん体たい在外ざいがい面めん是ぜ凹凸おうとつ不平ふへい的てき，每まい个“凹凸おうとつ”代表だいひょう一いち个单一いち的てき个虫，但ただし整体せいたい上じょう近きん乎光滑すべり，虽然每ごと个个虫ちゅう都と在ざい其内部ぶ穿孔せんこう。

火ひ体たい虫むし群ぐん体からだ是ぜ浮游生物ふゆうせいぶつ，这意味いみ着ぎ它们的てき运动在ざい很大程度ていど上じょう受海流りゅう，潮汐ちょうせき和かず海かい浪なみ的てき控ひかえ制せい。 然しか而，在ざい较小的てき范围内ない，每まい个群体たい都と可か以通过喷射しゃ推进的てき过程缓慢移うつり动，这是由よし所有しょゆう群ぐん体からだ的てき鳃笼中ちゅう的てき纤毛的てき协调跳とべ动产生せい的てき，这也产生了りょう进食流りゅう。

火ひ体たい虫むし是ぜ明あきら亮あきら的てき生物せいぶつ发光体からだ，闪烁着ぎ浅あさ蓝色绿色的てき光ひかり，能のう够看到いた数すう十じゅう米まい外的がいてき区域くいき。其名称めいしょう Pyrosoma来き自じ希まれ腊语(Pyro ="火ひ（fire）"， soma ="主体しゅたい（body）")。火ひ体からだ虫ちゅう与あずか樽たる海鞘ほや有ゆう亲缘关系，有ゆう时被称しょう为"火ひ樽だる海鞘ほや"。水すい手しゅ在ざい海上かいじょう偶尔会かい观察到平静へいせい的てき海面かいめん中ちゅう含有がんゆう很多火ひ体からだ虫ちゅう，所有しょゆう的てき一切都在黑夜里发光。

Bioluminescence

Although many planktonic organisms are bioluminescent, pyrosome 生物せいぶつ发光 is unusual in its brilliance and sustained light emission, and evoked the following comment when seen by scientist 托たく马斯·亨とおる利り·赫胥黎はじむ at sea:

"I have just watched the moon set in all her glory, and looked at those lesser moons, the beautiful Pyrosoma, shining like white-hot cylinders in the water" (T.H. Huxley, 1849).

Section through the wall of a pyrosome (magnified) showing a single layer of ascidiozooids; br) branchial orifice; at) atrial orifice; tp) process of the test; br s) branchial sac

Pyrosomes often exhibit waves of light passing back and forth through the colony, as each individual zooid detects light and then emits light in response. Each zooid contains a pair of light organs located near the outside surface of the tunic, which are packed with luminescent organelles that may be intracellular bioluminescent bacteria. The waves of bioluminescence that move within a colony are apparently not propagated by neurons, but by a 光子こうし process. Flashing zooids not only stimulate other zooids within the colony to bioluminesce, but nearby colonies will also display bioluminescence in response. Colonies will bioluminesce in response to mechanical stimulation (touch), as well as to light.

Species

Pyrosoma atlanticum by a tide pool in California

The following 物もの种 are accepted as valid by the World Register of Marine Species:

• Pyrosoma aherniosum Seeliger, 1895
• Pyrosoma atlanticum Péron, 1804
• Pyrosoma godeauxi van Soest, 1981
• Pyrosoma ovatum Neumann, 1909

Bloom in North Pacific

In 2017, pyrosomes were observed to have spread in unprecedented numbers along the 太平洋たいへいよう coast of 北美きたみ洲しゅう as far north as 阿おもね拉ひしげ斯加州かしゅう. The causes remain unknown, but one hypothesis is that this bloom may have resulted in part from unusually warm water along the coast over several preceding years. Scientists were concerned that should there be a massive die-off of the pyrosomes, it could create a huge dead zone (ecology) as the 分解ぶんかい作用さよう of their bodies consumed much of the 氧 dissolved in the surrounding seawater.。

參考さんこう文獻ぶんけん

• Bone, Q. (编). The Biology of Pelagic Tunicates [浮游ふゆう被ひ囊动物ぶつ生物せいぶつ学がく]. Oxford University Press. 1998: 340 pp. （英えい语）. 

外部がいぶ連結れんけつ

有ゆう關本せきもと分類ぶんるい的てき更さら多た信しん息いき，请参阅「火ひ体たい虫むし属ぞく」。

• Huge pyrosome captured in the North Atlantic - story and images
• Images taken by divers off southern California
• The Bioluminescence Web Page
• Divers with huge southern hemisphere pyrosomes
• Millions of tropical sea creatures invade waters off B.C. coast
• Researchers Investigate Explosion in the Number of Pyrosomes off Alaska
• R R Helm. The 60 foot long jet powered animal you’ve probably never heard of. Deep Sea News. 1 August 2013.