At night along the sea’s edge, the ocean sometimes seems to glow, as if lit from within. This glow is the result of bioluminescence, a phenomenon exhibited by many of the sea’s zooplankton. Bioluminescence is the production of cold light through internal biological processes, as opposed to phosphorescence or fluorescence, both of which are re-emitted light that was initially absorbed from an external source.

Many of the sea’s creatures, including squid, dinoflagellates, bacteria, worms, crustaceans, and fish, are known to produce light. The process that marine creatures use to create light is like that of the common firefly and similar to that which creates the luminous green color seen in plastic glow sticks, often used as children’s toys or for illumination during nighttime events. When a glow stick in bent, two chemicals mix, react, and create a third substance that gives off light. Bioluminescent organisms do essentially the same thing; they have a substance, called luciferin, that reacts with oxygen in the presence of enzyme, luciferase. When the reaction is complete, a new molecule is formed that gives off light—glowing blue—green in the underwater world. This biologically driven chemical reaction occurs within the organism’s special light-producing cells, called photocyptes, or light-producing organs, called photophores. Probably one of the most complex light-producing systems is that of the squid. Some squid have both photophores and chromatophores (organs for changing color) with their skin, thus enabling them to control both the color and intensity of the light produced. Recent research has also revealed that in some squid and fish, bioluminescent light may be produced by bacteria that live in a mutually beneficial partnership inside the animal’s light organs.

How and why bioluminescence occurs is not fully understood; however, in the undersea realm, it appears to be used in a variety of interesting and ingenious ways. The most commonly observed form of bioluminescence in the sea id the pinpoint sparking of light at night that can create cometlike trails behind moving objects. Almost always, this is the result of dinoflagellates reacting to water motion. The relatively short, momentary displays of light may have evolved to startle, distract, or frighten would-be predators. Collection nets brought up from the sea’s depths at night frequently glow green at great distance. Slowly fading green blobs or pulses of light can be seen coming from the organisms within, often from gelatinous creatures. This type of light display may be used to stun disorient, or lure prey. Like a wide-eyed deer caught on a road and dazed by headlights, undersea creatures living within the ocean’s darkness may be momentarily disoriented by short flashes of bioluminescent light. Another of the sea’s light-producing organisms is a small copepod (a type of crustacean) named Sapphirina iris. In the water, Sapphirina creates short flashes of a remarkably rich, azure blue light. But its appearance under a microscope is even more spectacular, the living copepod appears as if constructed of delicately handcrafted, multicolored pieces of stained glass. Within the deep sea, some fish also have a dangling bioluminescent lure or a patch of luminescent skin near the mouth, which may be used to entice unsuspecting prey.

Other sea creatures have both light-sensing and light-producing organs. These creatures are thought to use bioluminescence as a form of communication or as a means of identifying an appropriate mate. In the lantern fish, the pattern of photophores distinguishes one species from another. In other fish, bioluminescence may help to differentiate males from females. The squid uses light as a means of camouflage. By producing light from the photophores on its underside, the squid can match light form above and become nearly invisible to predators looking up from below. Squid, as well as some of the gelatinous zooplankton, have also been known to release luminescent clouds or strands of organic material, possibly as a decoy to facilitate escape. And finally, because what they eat is often bioluminescent, many of the transparent deep-sea creatures have red or black stomachs to hide the potentially flashing contents of ingested bioluminescent creatures. Without such a blacked-out stomach, their digestive organs would flash like a neon sign that says, “Eat me, eat me!”

在夜晚的海面上，海洋有时似乎会发光，好像从内部发光一样。这种光是生物发光的结果，而这是许多海洋浮游动物所表现出来的现象。生物发光是通过内部生物过程所产生的冷光，而不是磷光或荧光，这两种光都是最初从外部源所吸收的重新发出的光。 众所周知，许多海洋生物，包括乌贼，甲藻，细菌，蠕虫，甲壳类动物和鱼类都可以产生光。海洋生物制造光的过程就像普通萤火虫一样，类似于在塑料发光棒中产生明亮的绿色，通常用作儿童玩具或夜间活动时的照明。当荧光棒弯曲时，两种化学物质混合，反应并产生第三种发出光的物质。生物发光物在本质上是一样的；他们有一种叫做荧光素的物质，在酶，萤光素酶的存在下与氧反应。当反应完成后，会形成一种新的分子，在海底发出发光—亮蓝色—绿色的光。这种生物驱动化学反应发生在生物体的特殊的发光细胞中，称为photocyptes，或发光器官，称为发光器。可能是其一个最复杂的光生产系统是乌贼。有些乌贼在皮肤上同时具有发光器和色素细胞（用于改变颜色的器官），从而使它们能够控制光所产生的颜色和强度。最近的研究还显示，在一些乌贼和鱼类中，生物发光的光可能由生活在动物光器官中互相合作的细菌产生的。 生物发光的方式以及原因尚不完全清楚;然而，在海底，它似乎在各种有趣和巧妙的方式中使用。在海洋中最常见的生物发光形式是夜晚光线的闪烁，这些光可以在移动的物体后面形成类似于彗星般的痕迹。几乎总是这样，这是甲藻对水运动的反应。相对短暂的光显示可能演变为惊吓、分散或惊吓潜在的掠食者。夜间从海底深处收集的渔网经常在远处发出绿光。从生物体内可以看到，缓慢消退的绿色斑点或光脉冲，它们通常来自凝胶状的生物。这种类型的光显示器可能会用来眩晕迷惑，或引诱猎物。就像一只大眼睛的鹿，被汽车前灯弄得眩晕，生活在海洋黑暗中的海底生物可能会短暂地被生物发光的光线所误导。而另一种海海洋发光生物是一种叫做Sapphirina iris虹膜的小桡足类（一种甲壳类动物）。在水中，Sapphirina发出了一种非常丰富，天蓝色的光。但它在显微镜下的外观更加壮观，活桡足类看起来好像是由精致的手工制作的彩色玻璃构成。在深海中，有些鱼类在嘴边也有悬挂生物发光诱饵或一片发光的皮肤，可以用来吸引不知情的猎物。 其他海洋生物同时拥有感光和发光器官。这些生物被认为是使用生物发光作为一种交流形式或作为识别合适配偶的一种手段。在灯笼鱼中，发光物的图案将一个物种与另一个物种区分开来。在其他鱼类中，生物发光可能有助于区分雄性和雌性。乌贼用光作为伪装的手段。通过用下面的发光器发光，乌贼可以与上面的光线相匹配，使得掠食者从下往上看几乎看不见。乌贼，以及一些凝胶状的浮游动物释放发光云或有机物质链，可能作为诱饵帮助逃跑。最后，最后，因为他们吃的东西往往是发光的，很多透明的深海生物都有红色或黑色的胃，来隐藏潜在摄入的发光生物。如果没有这样一个黑色的胃，他们的消化器官就会像霓虹灯一样闪烁说：“吃我，吃我！”