Snails with penises will help assess the Arctic pollution

Adult females of tiny snails of the genus Boreocingula could grow underdeveloped male reproductive organs, scientists from St. Petersburg University have discovered. It can be a reaction to the pollution of the Arctic seas.

Some species of molluscs are hermaphroditic: they have both male and female genitals but sometimes molluscs can change their sex throughout life. As an extremely rare anomaly, however, a mollusc can develop sexual characteristics of another sex.

According to a research paper published in Polar Biology, it happened with sexually mature females of the Boreocingula martyni mollusc: a small rudimentary penis was found in all snails. Specialists collected samples of this species in Rogers Bay on Wrangel Island and in Pevek Bay in Chukotka. These territories are polluted by organotin compounds, harmful substances that were previously used in paints to protect ship hulls against fouling. In 2008, an international convention came into force prohibiting anti-fouling systems with organotin compounds. Studies have shown a correlation between the number of mollusc pseudohermaphrodites and the concentration of organotin compounds in their habitat.

‘This allows us to suggest a hypothesis that the B. martyni micromolluscs can be used for bioindication of marine pollution,’ said Ivan Nekhaev, a scientist from the Laboratory of Macroecology and Biogeography of Invertebrates, St Petersburg University. ‘The fact is that at present it is cheaper to gather a few dozen snails and open them than to analyse water samples. Such work can be carried out, for example, at specially equipped stations near the coast. It will also become necessary to have a stereo microscope and a specially trained person. Moreover, the distribution density of micromolluscs is much higher than that of larger organisms. So, they are easier to be found.’

Photo credit: St. Petersburg State University.