ABSTRACT

The transition to life on a hard surface, i.e., periphytonic existence (see Section 1.1) is induced and stimulated by certain factors of the surface. Let us classify the types of induction (and stimulation) of settlement, taking the following circumstances into account. In the literature, the surface factors are usually divided into physical and biological. The latter helps to draw attention to the fact that they belong to the biological objects: macroalgae, invertebrate (or vertebrate) animals, or microfouling film. It should be noted that the so-called “biological factors” are such by origin. The concrete nature of their action may be, for instance, chemical or physical. Hereafter, the term “biological factors” will be preferred only for those whose origin is biological and whose mechanism is either unclear or unessential. Such biological factors may be microfouling films, surfaces of adult individuals of some species, etc. Settlement may be induced not only by purely physical and chemical surface factors; for instance, physico-chemical factors may interact or their conjoint influence may differ quantitatively from the simple sum total of the action of these factors. In such cases we shall speak of the combined action of factors. We will hold biological factors with an unidentified mechanism of action to have the same status as combined surface factors.