328
V. Rossi et al.
homozygotes observed in August 1997 and then
monomorphism; considering that, since this
date, the frequency of the most common allele is
higher than 95%. At the Chioggia station we can
hypothesise a similar but very delayed situation
due to the relatively low chemical pollution and
to absence of thermal pollution. Barnacles are,
indeed, able to uptake and accumulate heavy
metals at a concentration factor of at least 10 3
(Barbaro et al. 1978). At the same time, they present mechanisms for the detoxification of the
stored metals (Rainbow and White 1989). At this
site, mortality never exceeds 20% but significant
excess of homozygotes with respect to the
Hardy-Weinberg equilibrium is observed only
in April 98, after 310 days from panel immersion.
We suggest that, in general, environmental
pollutants act as selective factors on recruitment
of B. amphitrite at the Industrial Channel station.
On the other hand thermal pollution seems
important to account for dominance of B.
amphitrite on experimental panels from the
power plant outflow because its lower sensitivity
to warmer temperature with respect to both B.
eburneus and other congeners described in the
Venice Lagoon (Nevo et al. 1977). Differences in
enzymatic activity between genotypes and
among sites seem to indicate the highest fitness
and plasticity of the homozygote organisms. But,
the relationship between enzymatic activity and
sampling season might mask or twist the affect
of other factors that could affect the population
dynamics and the age-class structure. Moreover,
competitive advantage of B. amphitrite and, in
particular of homozygous individuals at GPI
locus, might decrease in sites away from the
highly thermally polluted site. The reason
behind this situation is not clear but some cost,
or adaptive trade-off. may result from possessing
a more efficient detoxification mechanism eventually coupled with the highest enzymatic activity.
Acknowledgements. We would like to thank Prof. Battaglia, Dr.
R. Cironi and Prof. T. Patarnello for aiding in the initial set up
of the project and the staff of the Stazione Idrobiologica
dell'Universitlt di Padow (Chioggia) and of the Centrale
ENEL di Fusina for use of facilities and assistance with the
sampling work. This research was supported by ENEL (Ente
Nazionale per l'Bnergia Elettrica) contract NO 352122103
20.2.97 and by the research programme "Conservazione della
biodiversita e gestione sostenibile dei biotopi salmastri delle
coste italiane" (MURST 97).
References
Anil AC, Kurian J (1996) Influence offood concentration, temperature and salinity on the larval development of Balanus
amphitrite. Mar Biol127: 115-124
Barbaro A, Francescon A, Polo B, BHio M (l978) Balanus
amphitrite (Cirripedia: Thoracica) - a potential indicator of
fluoride, copper, lead, chromium and mercury in North
Adriatic Lagoons. Mar Bio146: 247-257
Brunetti R. Marin M. Beghi 1, Bressan M (1983) Study of pollution
in the Venetian lagoon's lower basin during the period 19741981. Riv Idrobiol22: 27-58.
Bryan PI. Rittschof D, McClintock JB (1996) Bioactivity of echinoderm ethanolic body-wall extracts- an assessment of
marine bacterial attachment and macro invertebrate larval
settlement. J Exp Mar BioI Ec01196: 79-96
da Silva EP, Sole-Cava AM (1994) Genetic variation and population structure in the tropical marine bivalve Anoma/ocamia
brasiliana (Gmelin) (Veneridae). In: Beaumont AR (ed)
Genetics and evolution of aquatic organisms. Chapman and
Hall, London, pp 159-168
Donazzolo R, Orio AA, Pavoni B, Perin G (1984) Heavy metals in
sediments of the Venice Lagoon. Oceanol Acta 7: 25-31
Fairbrother JE, Beaumont AR (1993) Heterozygote deficiencies in
a cohort of newly settled Mytilus edulis spat. r Mar BioI
Assoc UK 73 647-653
Gosselin LA, Qian PY (1996) Early and post-settlement mortality
of an intertidal barnacle: a critical period for survival. Mar
Ecol Prog Ser 135: 69-75
Harris H, Hopkinson DA (1976) Handbook of enzyme electrophoresis in human genetics. North-Holland Publ Co,
Amsterdam
Hedgecock D (1994) Does variance in reproductive success limit
effective population size of marine organisms? In:
Beaumont AR (ed) Genetics and evolution of aquatic organisms. Chapman and Hall, London, pp 122-134
Holm Er, Bourget E (1994) Balanoides in the Northwest Atlantic
and Gulf of St-Lawrence. Mar Ecol Prog Ser 113: 247-256
Hu YP, Lutz RA. Vdjenhoek RC (1993) Overdominance in earlylife stages of an american oyster strain. J Hered 84: 254-258
Hummel H, Patarnello T (1994) Genetics and pollution. In:
Beaumont AR (ed) Genetics and evolution of aquatic organisms. Chapman and Hall, London, pp 425-434
Judge ML, Quinn JF, Wolin CL (1988) Variation in recruitment of
Balanus glandula (Darwin 1854) along the central California
coast. J Exp Mar BioI Ecol119: 235-251
Montanini E, Antonietti R. Ferrari G, Marchiani C, Rossi V (1998)
The effects of thermal pollution on gastropod populations
in the Po River (Northern Italy). Verh Int Ver Limnol 26:
2103-2106
Montero C, Battaglia B, Stenico M, Campesan G, Patarnello T
(1994) Effects of heavy metals and temperature in the genetic structure and GPI enzyme activity of the barnacle
Balanus amphitrite Darwin (Cirripedia: Thoracica). In:
Beaumont AR (ed) Genetics and evolution of aquatic organisms. Chapman and Hall, London, pp 447-439
Nevo E, Shimony T, Libni M (1977) Thermal selection of allozyme
polymorphisms in barnacles. Nature 267: 699-701
O'Connor NJ, Richardson DL (1998) Attachment of barnacle
(Balanus amphitrite Darwin) larvae: responses to bacterial
films and extracellular materials. J Exp Mar BioI Ecol 226:
115-129
Patarnello T, Guinez R, Battaglia B (1991) Effects of pollution on
heterozygosity in the barnacle Balanus amphitrite
V. Rossi et al.
homozygotes observed in August 1997 and then
monomorphism; considering that, since this
date, the frequency of the most common allele is
higher than 95%. At the Chioggia station we can
hypothesise a similar but very delayed situation
due to the relatively low chemical pollution and
to absence of thermal pollution. Barnacles are,
indeed, able to uptake and accumulate heavy
metals at a concentration factor of at least 10 3
(Barbaro et al. 1978). At the same time, they present mechanisms for the detoxification of the
stored metals (Rainbow and White 1989). At this
site, mortality never exceeds 20% but significant
excess of homozygotes with respect to the
Hardy-Weinberg equilibrium is observed only
in April 98, after 310 days from panel immersion.
We suggest that, in general, environmental
pollutants act as selective factors on recruitment
of B. amphitrite at the Industrial Channel station.
On the other hand thermal pollution seems
important to account for dominance of B.
amphitrite on experimental panels from the
power plant outflow because its lower sensitivity
to warmer temperature with respect to both B.
eburneus and other congeners described in the
Venice Lagoon (Nevo et al. 1977). Differences in
enzymatic activity between genotypes and
among sites seem to indicate the highest fitness
and plasticity of the homozygote organisms. But,
the relationship between enzymatic activity and
sampling season might mask or twist the affect
of other factors that could affect the population
dynamics and the age-class structure. Moreover,
competitive advantage of B. amphitrite and, in
particular of homozygous individuals at GPI
locus, might decrease in sites away from the
highly thermally polluted site. The reason
behind this situation is not clear but some cost,
or adaptive trade-off. may result from possessing
a more efficient detoxification mechanism eventually coupled with the highest enzymatic activity.
Acknowledgements. We would like to thank Prof. Battaglia, Dr.
R. Cironi and Prof. T. Patarnello for aiding in the initial set up
of the project and the staff of the Stazione Idrobiologica
dell'Universitlt di Padow (Chioggia) and of the Centrale
ENEL di Fusina for use of facilities and assistance with the
sampling work. This research was supported by ENEL (Ente
Nazionale per l'Bnergia Elettrica) contract NO 352122103
20.2.97 and by the research programme "Conservazione della
biodiversita e gestione sostenibile dei biotopi salmastri delle
coste italiane" (MURST 97).
References
Anil AC, Kurian J (1996) Influence offood concentration, temperature and salinity on the larval development of Balanus
amphitrite. Mar Biol127: 115-124
Barbaro A, Francescon A, Polo B, BHio M (l978) Balanus
amphitrite (Cirripedia: Thoracica) - a potential indicator of
fluoride, copper, lead, chromium and mercury in North
Adriatic Lagoons. Mar Bio146: 247-257
Brunetti R. Marin M. Beghi 1, Bressan M (1983) Study of pollution
in the Venetian lagoon's lower basin during the period 19741981. Riv Idrobiol22: 27-58.
Bryan PI. Rittschof D, McClintock JB (1996) Bioactivity of echinoderm ethanolic body-wall extracts- an assessment of
marine bacterial attachment and macro invertebrate larval
settlement. J Exp Mar BioI Ec01196: 79-96
da Silva EP, Sole-Cava AM (1994) Genetic variation and population structure in the tropical marine bivalve Anoma/ocamia
brasiliana (Gmelin) (Veneridae). In: Beaumont AR (ed)
Genetics and evolution of aquatic organisms. Chapman and
Hall, London, pp 159-168
Donazzolo R, Orio AA, Pavoni B, Perin G (1984) Heavy metals in
sediments of the Venice Lagoon. Oceanol Acta 7: 25-31
Fairbrother JE, Beaumont AR (1993) Heterozygote deficiencies in
a cohort of newly settled Mytilus edulis spat. r Mar BioI
Assoc UK 73 647-653
Gosselin LA, Qian PY (1996) Early and post-settlement mortality
of an intertidal barnacle: a critical period for survival. Mar
Ecol Prog Ser 135: 69-75
Harris H, Hopkinson DA (1976) Handbook of enzyme electrophoresis in human genetics. North-Holland Publ Co,
Amsterdam
Hedgecock D (1994) Does variance in reproductive success limit
effective population size of marine organisms? In:
Beaumont AR (ed) Genetics and evolution of aquatic organisms. Chapman and Hall, London, pp 122-134
Holm Er, Bourget E (1994) Balanoides in the Northwest Atlantic
and Gulf of St-Lawrence. Mar Ecol Prog Ser 113: 247-256
Hu YP, Lutz RA. Vdjenhoek RC (1993) Overdominance in earlylife stages of an american oyster strain. J Hered 84: 254-258
Hummel H, Patarnello T (1994) Genetics and pollution. In:
Beaumont AR (ed) Genetics and evolution of aquatic organisms. Chapman and Hall, London, pp 425-434
Judge ML, Quinn JF, Wolin CL (1988) Variation in recruitment of
Balanus glandula (Darwin 1854) along the central California
coast. J Exp Mar BioI Ecol119: 235-251
Montanini E, Antonietti R. Ferrari G, Marchiani C, Rossi V (1998)
The effects of thermal pollution on gastropod populations
in the Po River (Northern Italy). Verh Int Ver Limnol 26:
2103-2106
Montero C, Battaglia B, Stenico M, Campesan G, Patarnello T
(1994) Effects of heavy metals and temperature in the genetic structure and GPI enzyme activity of the barnacle
Balanus amphitrite Darwin (Cirripedia: Thoracica). In:
Beaumont AR (ed) Genetics and evolution of aquatic organisms. Chapman and Hall, London, pp 447-439
Nevo E, Shimony T, Libni M (1977) Thermal selection of allozyme
polymorphisms in barnacles. Nature 267: 699-701
O'Connor NJ, Richardson DL (1998) Attachment of barnacle
(Balanus amphitrite Darwin) larvae: responses to bacterial
films and extracellular materials. J Exp Mar BioI Ecol 226:
115-129
Patarnello T, Guinez R, Battaglia B (1991) Effects of pollution on
heterozygosity in the barnacle Balanus amphitrite