Download Fouling Community Studies in the Indian River

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Mook, D .H. 1.975.
Abstract
Fouling Community Studies in the Indian River
Introduction
The development of fouling communities is not well
understood, but it is known that the spawning periods of
the fouling organisms and local environmental factors
will influence the development and structure of the
fouling community.
Factors such as temperature (Barnes
and Powell, 1953), salinity (Barnes and Barnes, 1974),
depth (DePalma, 1962), light (McDougall, 1943; Berrill,
1950), substrate material (Pomeratand Weiss, 1946)
and position (McDougall, 1953) have been discussed in
the literature.
Paine (1966) and Connell (1961) discussed the effects
of predation and competition in determining the structure
of fouling communities.
Goodbody (1961) has stated that
inhibition of settlement of fouling organisms is also
important in determining species composition of fouling
communities.
Goodbody (1961) states that there is a definite
successional process in the fouling community leading to
a climax community.
Smith et al.
(1950) found no evidence
of succession in fouling communities in Biscayne Bay and
suggested that all changes were a result of some external
perturbation.
Sutherland and Karlson (1973) discuss the
difficulties in discerning the differences between community
succession and seasonal progression.
In a recent study
by Sutherland (1974), the fouling community was found to
have several stable states, each with a species missing.
He further extrapolates that there may be as many of these
stable states or boundlly points as there are species in
the community however many of these points may be "trivial".
Other studies have indicated that there may be several
stable points with all species present. However, they cannot
all be considered climax or globally stable communities
because they are not resistant to all perturbations.
The purpose of this study is to determine if a globally
stable or climax situation exists with the local fouling
community at the site of our laboratory and to suggest what
pathways the community takes to develop into this condition.
This paper
w~ll
report the seasonal settlement of fouling
organisms.
Methods and Materials
Unglazed clay tiles (15 x 15 cm) were suspended about
10 cm below the surface from a barge in the Link Port canal.
Plates were put in the water for a 2 wk. , 1 mo., 3 mo., 6 mo . ,
and 1 yr. time intervals and examined at the end of these
periods.
All sessile organisms were identified, counted
and their percent coverage estimated.
Results
All of the results are contained in Figure 1.
Fig 1. settlement of fouling organisms in Link Port
MONTH
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BALANUS
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Discussion
Barnacles were common settlers throughout the year
except in the summer and midwinter where they were conspiciously absent.
The chief specie
was Balanus eburneus
but Balanus amphitrite was also present.
The decrease in
settlement in June may have been due to lower salinities
which are known to effect barnacle larvae (Barnes and Barnes,
1974) or competition from Branchioma or Schitzoporella.
The dip in the winter may have been due to lower temperatures or competition from Spirorbis.
Moore and Albertson,
(1974) found a similar pattern of barnacle settlement in
Miami and suggested that temperature may play an important
part in the settlement of barnacles and that there may be
some competition between barnacles and tube worms.
Spirorbis settled heavily throughout the winter and its
settlement is just beginning to decrease at the present
time.
Hydroides also settled in the winter months but
not in as great numbers as Spirorbis.
The sabellid worm,
Branchioma bairdi along with the encrusting bryozoan
Schiczoporella unicornis settled in the late spring and
early summer and quickly dominated the plates and covered
up other organisms.
Only some of the colonial tunicates
and some barnacles were able to compete with them.
While
these organisms were present little else was able to
settle.
This may be the reason for the reduced number of
species found at that time.
Bugula stolonifora and Bugula neritina were common
settlers
in the winter months but absent from plates the
rest of the year.
These animals are considered to be winter
organisms in Florida (Moore and Albertson, 1974) so this
pattern would be expected.
Hippoporina verelli, a warm
water encrusting bryozoan was absent from most mid-winter
plates but present the rest of the year except in the late
spring, when it may have been outcompeted by Schitzoporella.
Conopeum is present from early fall to late spring.
Since
Conopeum is generally considered to be a poor competitor
(Dudley, 1973), its absence in the late spring and summer
could be a result of competition rather than absence of
larvae.
Late spring and summer plates were generally
completely covered with organisms while fall and winter
plates were more sparsely settled.
The colonial ascidian Diplbsoma macdonaldi was
common most of the year however the colonies reached greater
size in the spring, often covering large areas of the plates.
Some of the Botryllinae tunicates, Botryllus planus,
Botrylloides nigrum and Symplegma viride were able to colonize
areas on top of the Diplosoma and build rather large colonies
in the spring.
The solitary tunicate Styela plicata
a~d
oysters were
not common on short term plates even though they seemed
COMnon on sea walls and older plates.
This indicates that
these species may have a preference towards older plates.
Long term plates will have to be examined to understand
the settlement of these organisms.
Summary
The differences between short term plates indicate
that there is a great difference between pioneer species
throughout the year.
Because of these differences, the
pathways that the fouling community must take towards
a potential climax condition must vary widely, depending
on what time of year the substrate is immersed in the water.
Data collected from 3 and 6 month plates indicates that
Styela plicata and oysters may be important in at least one
stable state of the fouling community.
These organisms have
been common fo£ several years on pilings and sea walls in the
area but it is not known whether this represents a climax
situation.
More experiments will have to be done with long
term plates to find out what constitutes a climax state of
the fouling community.
Literature Cited
Barnes, H. and M. Barnes. 1974. The responses during
development of the embryos of some common cirripeds
to wide changes in salinity, J. EXp. Mar. BioI. Ecol.
15:197-202.
Barnes, H. and H. Powell.
1953. The growth of Balanus
balanoides and B. crenatus under varying conditions
of submersion. -J. Mar. BioI. Ass. U. K. 32:107-128.
Berrill, N.
1950. The tunicata with an account of the
British species. The Ray Society. London.
354 p.
Connell, J. 1961. Effects of competition by Thias
lapillus and other factors on natural populations
of the barnacle Balanus balanoides. Ecol. Monog.
31:61-104.
DePalma, J.
1962. Marine fouling and boring organisms in
the Tongue of the Ocean, Bahama Exposure 11. Unpublished manuscript.
Dudley, J.
1973. Observations in the reproduction, early
larval development and colony of Astoseny and Canopeui~
t.enu i.ssirnum. Science 14:270-278.
--_._-Goodbody, I.
1961. Inhibition of the development of a
marine ~essile community. Nature 190:282-283.
McDougall, K. 1943.
Beaufort, N. C.
Sessile marine invertebrates of
Ecological Monog. 13:323-374.
Moore, H., H. Albertson and Sigmund Miller. 1974. Long
term changes in the settlement of barnacles in the
Miami area. Bull. Mar. Sci.
24(1):86-100.
Paine, R.
1966. Food web complexity and species diversity.
Am. Nat. 100:65-75.
Pomerat, C. and C. Weiss.
1946. The influence of texture
and composition of surface on the attachment of
sedentary marine organisms.
Smith, F., R. Williams and C. Davis. 1950. An ecological
survey of the subtropical inshore waters adjacent to
Miami. Ecol. 31:ll9-r46.
Sutherland, J. and R. Karlson.
1973. Succession and
seasonal progression in the fouling community at
Beaufort, N.C. Unpublished manuscript.
Sutherland, J.
1974. Mult~ple stable points in natural
communities. Am. Nat. 108:859-873.
Presented to the
39th Annual Meeting
of the Florida Academy of Sciences