1063-0740/05/3106- © 2005 Pleiades Publishing, Inc.
Russian Journal of Marine Biology, Vol. 31, No. 6, 2005, pp. 367–372.
Original Russian Text Copyright © 2005 by Biologiya Morya, Dobretsov.
The surface of any substrate immersed into the sea
is ﬁrst, as a rule, colonized by microfouling organisms
(mostly bacteria and microalgae) and then by macrofoul-
ing (invertebrate larvae and macroalgae spores) .
When more developed, biofouling leads to wear on the
surface material, to intensiﬁed corrosion, and to an
increase in ship fuel consumption . The damage by
fouling to ships, wharfs, platforms, and water-working
equipment amounts about $50 billion annually world-
wide . There are, as yet, no universal antifouling
products that are not poisonous to the environment
[27, 29]. Therefore, at present, the most essential task is
to search the atoxic means of defense against fouling.
The larvae and spores of fouling organisms settle on
the surface of both artiﬁcial substrates and marine
organisms . Settlement of the dispersal stages in
fouling organisms (epibionts) on the surface of living
creatures is called epibiosis. Many attached and slow-
moving organisms, such as sponges, ascidia, soft cor-
als, and algae often use chemical substances that kill
and repel epibionts . The phaeophytes
, for instance, prevent
the settlement of the mussel
a repellent into the water [4, 8], and the ﬁlamentous
sp. inhibits larval settlement of
by chemical substances [5, 6]. During laboratory
experiments, the marine sponge
suppressed the growth of diatoms and larval settlement
of polychaetes, while in nature it changed the composi-
tion of the adjacent fouling community .
It has been suggested that the larval settlement
inductors are water-soluble compounds, while the
inhibitors are poorly soluble and low molecular com-
pounds effective at low concentrations [31, 32]. The
furanons excreted by the red algae
prevent fouling very effectively , and amino acids
induce larval settlement of oysters [33, 35] and poly-
Bacteria in the microfouling ﬁlm are known to
attract and to scare invertebrate larvae [23, 25, 36]. It is
likely, therefore, that marine macroalgae and attached
invertebrates may suppress the fouling processing on
their surface both by direct use of chemical substances
and by means of surface-living bacteria. Bacteria iso-
lated from ascidium  and from sponges  sup-
press larval settlement under laboratory conditions. The
bacteria used in our work were isolated from the sur-
face of several organisms: the green algae
, the soft coral
sp., and the sponge
sp. The bacterial effects were analyzed during
the experimental larval settlement of the polychaete
and the bryozoan
which are mass fouling organisms in tropical waters .
The goals of this investigation were the following:
isolation of bacteria from the surface of
sp.; study of bacte-
rial ﬁlm and water extract effects on the larval settle-
; and determination
of the molecular mass and other characteristics of anti-
fouling substances excreted by bacteria.
Suppression of Settlement of Larvae of Fouling Organism
by Water-Soluble Substances from Epibiotic Bacteria
S. V. Dobretsov
Saint Petersburg State University, St. Petersburg, 199034 Russia
Received February 14, 2005
—Twenty-nine bacterial strains were isolated from the surface of the green alga
sp., and the sponge
sp. The bacterial species
sp. 4, an unidentiﬁed
sp. 2, and
were found to suppress the larval settlement of the polychaete
(Haswell, 1883) and the bry-
(Linnaeus, 1758). Aqueous extracts of ﬁve bacteria (all those named above except
sp. 2) prevented larval settlement. Bacteria
sp. 4, and an unidenti-
were ﬁrst discovered to produce high-molecular substances (>100 kDa) preventing lar-
val settlement. Their activity was inhibited by amylase treatment, while trypsin and papain did not inﬂuence
their activity. The data obtained proved that bacteria from the surface of the number of marine organisms
excrete water-soluble sacchariferous compounds preventing larval settlement.
marine biofouling, bacteria, chemical defense, epibiosis, settlement, larvae.