The Danubian cryptic invader Theodoxus fluviatilis (Gastropoda: Neritidae) in the River Rhine: a potential indicator for metal pollution?

Rothmeier, Louisa Marie ORCIDiD
Martens, Andreas ORCIDiD
Watermann, Burkard ORCIDiD
Grabow, Karsten
Bartz, Jennifer
Sahm, René ORCIDiD

DOI: https://doi.org/10.1007/s10646-021-02485-4
Persistent URL: http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/11057
Rothmeier, Louisa Marie; Martens, Andreas; Watermann, Burkard; Grabow, Karsten; Bartz, Jennifer; Sahm, René, 2021: The Danubian cryptic invader Theodoxus fluviatilis (Gastropoda: Neritidae) in the River Rhine: a potential indicator for metal pollution?. In: Ecotoxicology, 31, 1, 24-32, DOI: https://doi.org/10.1007/s10646-021-02485-4. 
 
Rothmeier, Louisa Marie; Institute for Biology, University of Education, Karlsruhe, Germany
Martens, Andreas; Institute for Biology, University of Education, Karlsruhe, Germany
Watermann, Burkard; LimnoMar Laboratory for Freshwater and Marine Research, Hamburg, Germany
Grabow, Karsten; Institute for Biology, University of Education, Karlsruhe, Germany
Bartz, Jennifer; German Environment Agency, Berlin, Germany
Sahm, René; German Environment Agency, Berlin, Germany

Abstract

Metal pollution poses a major threat to aquatic systems especially in anthropogenic influenced areas, in as much as metals are persistent in the environment. The freshwater snail Theodoxus fluviatilis has often been used as an indicator species for the ecological status in river monitoring. In the River Rhine, the native Northern-European form of T. fluviatilis is nowadays extinct, whilst the Danubian form is spreading along the river. The aim of our study was to investigate if the cryptic invader is affected by metal exposure present in the River Rhine and to discuss its potential as an indicator for metal pollution. Several environmental abiotic (14 water environmental variables plus five common metal concentrations in water and biofilm) and biotic parameters (biofilm mass) were measured across 23 sites along the River Rhine. Five population and six histopathological parameters were evaluated on snails collected at all 23 sites. Aqueous chromium concentration was positively correlated to the damage of male reproductive organs of T. fluviatilis, and higher ammonium concentration was correlated to a decrease in snail size and an increase in the proportion of juveniles. None of the analysed snail parameters was negatively correlated to concentrations of other metals measured, like copper and zinc. Therefore, based on the parameters evaluated, our results indicate that the Danubian form of T. fluviatilis is only restrictedly suitable as an indicator for metal pollution in the River Rhine system. Further field and laboratory investigations including other stressors are necessary to evaluate the indicator potential of the cryptic invader holistically.