Page:Popular Science Monthly Volume 73.djvu/90

86 plant life growing in bodies of still water, or even in running water where the bottom will permit the rooting of the plant. But in addition to this evident growth there is an enormous development of life, microscopic or transparent and invisible except when collected and studied by proper methods, which, in rapidity of growth and amount of mass may far outclass the visible portion. Some of this becomes apparent as green scum or as floating masses when its growth exceeds the capacity of the aquatic animals to consume it. Sometimes these minute algae become a great source of annoyance in water supplies if for any reason their multiplication is unchecked, since they give offensive odors and taste to the water.

It has been estimated that the rate of development in some of these organisms is such that the possible progeny of one individual would suffice to fill all the waters of the globe in less than a week.

This is significant to us here simply as showing the enormous possibility of these organisms in utilizing water and air in the formation of vegetable substance, which substance may, with proper utilization, be transformed into fertilizing agents for the production of valuable plant crops or into animals having direct commercial value. To understand this process, let us consider for a moment the relations existing among aquatic organisms. The algæ may be considered among the more simple and these develop with only water and air or the other inorganic contents of water, but they furnish food for an innumerable host of microscopic animals such as amœbæ, rotifers, etc., and these in turn are fed upon by others, such as microscopic Crustacea, which again form an important part in the diet of young fishes. These, when grown, or after furnishing the basis of food for other larger species, may reach our tables as human food. This, however, is but one line of transformation, as we have fishes of very different habits utilizing different kinds of aquatic life as food.

Where the life taken from the water does not balance the production, or where this product is not drained off into the sea, the accumulation of organic debris forms at the bottom a mass of richest organic matter, which by its decomposition may in a large part result in marsh gas, and in this form escape into the air.

Having indicated the possibility of an unworked phase of agriculture, or aquaculture, let us now turn to some of the possible lines of development in this field.

We have in America practically no established system of cropping our water areas. It is true that some progress has been made in the sponge farming of Florida, and oyster farming in Rhode Island, Connecticut, Virginia, North Carolina and Louisiana, but even these need further development to utilize the natural possibilities.

But so far as fresh-water culture goes, there is scarcely a