World Congress of Malacology Antwerp ... - Unitas Malacologica

Cytogenetic damage in aquatic mollusks as a biomarker of environmental pollution
Baršienė, Janina; Rybakovas, Aleksandras; Andreikėnaitė, Laura
Institute of Ecology of Vilnius University, Akademijos 2, 08412 Vilnius, Lithuania,
Email: janbar@ekoi.lt
The cytogenetic techniques used in this study proved to be a reliable tool for the evaluation of genetic
alterations induced by heavy metals, PAHs, crude oil, flame retardants and other dangerous
environmental agents. Cytogenetic damage – aneuploidy, polyploidy, meiotic injures, chromosomal
aberrations, micronuclei and other nuclear abnormalities were employed as a biomarkers of
environmental pollution and were evaluated in freshwater and marine mollusk species. In freshwater
mollusks, cytogenetic damage was assessed in different species (from Anodonta, Unio, Dreissena,
Viviparus, Melanopsis, Theodoxus, and other genera) inhabiting highly contaminated sites in rise and
orange-tree fields, in mountain and geothermal springs in eastern Spain, in environs of nuclear power
plants (Lithuania, Switzerland, Spain), in different water bodies of Lithuania, Switzerland, and
Poland. The highest level of cytogenetic disturbances was found in mollusks from the vicinities of
Cofrentes NPP, from geothermal spring and canals in orange-tree fields (eastern Spain), Murten Lake
(Switzerland, in nearby two NPPs are located), in rivers below biggest cities. The frequency of
aneugenic and clastogenic effects in mollusks from heavily contaminated sites was 3-10 times higher
than in mollusks from the reference sites.
In marine mollusks, micronuclei and other nuclear abnormalities were applied to assess mutagenicity
in different zones of the Baltic, North Sea and Atlantic Ocean. Relevance of mollusks to monitor
environmental mutagenicity was proved in long-term monitoring of cytogenetic damage in mussels
and fish after the oil spill in the Baltic Sea. Caged and native bivalves were used in studies of
genotoxic effects appeared around different offshore oil platforms in the North and Barents Sea. A
clear relationship between concentrations of crude oil, different alkylphenols, flame retardants and
levels of cytogenetic damage was found in experimental exposures of mussels (IRIS, Norway).
3D microanatomy of Omalogyra atomus (Gastropoda, Omalogyridae)
Bäumler, Natalie; Zernecke, Rebekka; Haszprunar, Gerhard; Ruthensteiner, Bernhard
Zoologische Staatssammlung München, Münchhausenstraße 21, 81247 Munich, Germany,
Email: natalie.baeumler@t-online.de; remz@gmx.de; haszi@zsm.mwn.de;
BRuthensteiner@zsm.mwn.de
The Omalogyridae includes many minute species – shell diameter usually less than one millimetre –
some of which have worldwide distribution. Despite of its small size, soft part anatomy of the very
common European member Omalogyra atomus (Philippi, 1841) has been investigated already in
1948 by Vera Fretter. Although considered as a basal member of Heterobranchia, the exact
systematic affinities of the Omalogyridae are unclear. A reinvestigation of O. atomus shall shed light
on the hypothesis of a possible progenetic origin of the Omalogyridae out of Architectonicidae.
Furthermore, direct comparison of the previous and the present results will enable evaluating the
advantages of the modern methods applied - “semithin” serial sectioning and computer-aided 3D
reconstruction.
The present data confirm most of the results obtained already by FRETTER 1948. In particular the
highly glandular nature of the foot and of the mantle cavity, the complete lack of a gill being
functionally replaced by prominent ciliary tracts, the relative simplicity of the gut and the high
complexity of the hermaphroditic reproductive system adapted for internal fertilization are the most
outstanding features of the snail’s anatomy.
Future comparative data on related species and genera will show, whether these characteristics can be
ascribed to the extreme smallness of the animals or can be considered as an adaptation to the highly
demanding habitat (tide pools) of O. atomus. Alternatively, at least some of the characters may be
caused by the heterobranch affinities of Omalogyridae. We hope to clear up the systematic position
19