Plankton are a floating community of plants and animals. Many are fragile constructions of jelly that would collapse without the support of water. Some are colonial and several feet long. Venus's girdle is two feet across and looks like a transparent moustache with curled up ends. It catches light in the beating hairs that ripple over its body as it moves slowly through the water. The animal plankton are unable to photosynthesise and sweep up the tiny plants and other edible particles in many different ways. One creature extends a forest of long tentacles in which smaller organisms get entangled. Another trails stinging threads and pulls them in whenever they catch anything. Some worms actively pursue their prey. Some are only part of the community when they are young larvae. They then grow up, change shape, and settle down to a more static life. But all are dependent on the tiny microscopic plants around them.