deep sea community

These yellow cells occur also in foraminifera, globigerina and orbitalites, and in corals and other invertebrates, as well as floating independently in the ocean.

In the legion of the radiolaria called Phiodaria, which inhabit the deep sea, the place of the yellow cells in the other radiolaria is apparently taken by the Phiodelae, dark-coloured cells, which may possibly be a lower form of algal life than the yellow cells and capable of evolving oxygen under the influence of the phosphorescence of deep-sea animals.

Blue-green algae, Cyanophyceae, predominate over all other algae in freshwater, but in the sea they are represented by only a few species and genera.

The well-known blossoming, or water bloom, of lakes at certain times of the year is due to the enormous development of certain species of Oscillatoriaceae, and something similar occurs in the ocean.

Phosphorescent light evidently plays an important role in deep-sea life.

Solenterates, like the alcyonarians, have frequently been brought up from great depths in a light-giving condition.

The coloring of deep-sea animals, mostly red and brown monotones without any patches of vivid colors, is doubtless correlated with the faint gleams of phosphorescent light.

It is probable that the animals giving out phosphorescent light are not evenly distributed throughout the deep sea, but are more or less localized, and may be more abundant in some localities than in others, while certain regions may be utterly devoid of light, but this does not account for the great variation in the development of the eyes in deep-sea forms, in some of which the eyes are very large, while in others the eyes are small or altogether wanting.