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P. 5. MEADOWS AND J. I. ClLMPBELL
presumably a first step would be the isolation and description of the
microbial species and of the organic material involved, followed by
culturing and inoculation of sterile sand in an attempt to restore its
attractiveness. An almost identical suggestion has been made by Wilson
(1958), and so it may be many years before we understand what
aspects of this extremely complex micro-habitat are important. Finally,
to add confusion to complexity, sands with an experimentally modified
microbial fauna exhibit changed physical properties (Webb, 1969).
2. The microbial fauna on f i t surfaces
Like sediments, the flat surfaces of rock, stones, and seaweeds as
well as those of man-made structures, such as concrete, ships’ bottoms
and glass slides, collect a recognizable spectrum of micro-organisms in
the sea and in fresh water. On these flat surfaces the micro-organisms
form a film that covers the whole surface; there are no bare surfaces
comparable to those on the surfaces of sand grains. The film formed by
micro-organisms on surfaces has often been called the primary or
microbial film although the concept has had a chequered career. The
following quotations represent the earliest references to it that could
be found : “ The organisms develop upon the slide in a fairly uniform
film ” (Henrici, 1933) ; “ Bacteria and, to a lesser extent, other microorganisms are the primary film formers on submerged glass slides ”
(Zobell and Allen, 1935); “Bacteria and closely related microorganisms, together with varying quantities of adsorbed organic matter
are the primary film formers ” (Zobell, 1938b). Following the formation
of a primary film the larvae of sedentary marine invertebrates that
settle on flat surfaces do so in progressively greater numbers (Zobell
and Allen, 1935; Scheer, 1945; Wood, 1950). Meadows (1964a) citing
earlier references felt that the primary film probably forms by three
processes: the attachment of micro-organisms, the production by these
micro-organisms of extra-cellular metabolites and slimes which then
become adsorbed to the surface, and the adsorption from sea water of
organic materials. This hypothesis could be tested by experiment.
Settling larvae of sedentary marine invertebrates react to the
primary film in a number of ways. The film’s presence either stimulates
(Miller et al., 1948; Cole and Knight-Jones, 1949; Wisely, 1958b; Crisp
and Ryland, 1960; Meadows and Williams, 1963; Straughan 1972) or
inhibits (Harris, 1946; Pyefhch and Downing, 1949 ; Crisp and Ryland,
1960) settlement, has contrary effects when observed by different workers
(Visscher, 1928 and Harris, 1946, on cirripedes), or no effect at all
(Wilson, 1968), depending on the species investigated. There have only
P. 5. MEADOWS AND J. I. ClLMPBELL
presumably a first step would be the isolation and description of the
microbial species and of the organic material involved, followed by
culturing and inoculation of sterile sand in an attempt to restore its
attractiveness. An almost identical suggestion has been made by Wilson
(1958), and so it may be many years before we understand what
aspects of this extremely complex micro-habitat are important. Finally,
to add confusion to complexity, sands with an experimentally modified
microbial fauna exhibit changed physical properties (Webb, 1969).
2. The microbial fauna on f i t surfaces
Like sediments, the flat surfaces of rock, stones, and seaweeds as
well as those of man-made structures, such as concrete, ships’ bottoms
and glass slides, collect a recognizable spectrum of micro-organisms in
the sea and in fresh water. On these flat surfaces the micro-organisms
form a film that covers the whole surface; there are no bare surfaces
comparable to those on the surfaces of sand grains. The film formed by
micro-organisms on surfaces has often been called the primary or
microbial film although the concept has had a chequered career. The
following quotations represent the earliest references to it that could
be found : “ The organisms develop upon the slide in a fairly uniform
film ” (Henrici, 1933) ; “ Bacteria and, to a lesser extent, other microorganisms are the primary film formers on submerged glass slides ”
(Zobell and Allen, 1935); “Bacteria and closely related microorganisms, together with varying quantities of adsorbed organic matter
are the primary film formers ” (Zobell, 1938b). Following the formation
of a primary film the larvae of sedentary marine invertebrates that
settle on flat surfaces do so in progressively greater numbers (Zobell
and Allen, 1935; Scheer, 1945; Wood, 1950). Meadows (1964a) citing
earlier references felt that the primary film probably forms by three
processes: the attachment of micro-organisms, the production by these
micro-organisms of extra-cellular metabolites and slimes which then
become adsorbed to the surface, and the adsorption from sea water of
organic materials. This hypothesis could be tested by experiment.
Settling larvae of sedentary marine invertebrates react to the
primary film in a number of ways. The film’s presence either stimulates
(Miller et al., 1948; Cole and Knight-Jones, 1949; Wisely, 1958b; Crisp
and Ryland, 1960; Meadows and Williams, 1963; Straughan 1972) or
inhibits (Harris, 1946; Pyefhch and Downing, 1949 ; Crisp and Ryland,
1960) settlement, has contrary effects when observed by different workers
(Visscher, 1928 and Harris, 1946, on cirripedes), or no effect at all
(Wilson, 1968), depending on the species investigated. There have only