A Tiny Feather Duster Worm in Lake Baikal - Observation of the Week 2019-02-25
Our Observation of the Week is this Manayunkia feather duster worm, seen in Russia by septima15!
Home to over 20% (!) of all the world’s surface freshwater, Russia’s Lake Baikal is Earth’s largest freshwater lake (by volume) and home to thousands of plant and animal species, the vast majority of which are endemic to its waters and surroundings.
Olga Medvezhonkova (septima15) works at a research institute near the lake, where she hydrobiology researcher. What does that entail? “Most of the time I spend on the beaches or the shallow lake area for sampling bottom animals and then studying them under a microscope to determine the taxon and count the number” is how she describes it. “This is part of the science of hydrobiology!”
“I met the polychaetes during the processing of the sample from a depth of 4-5 m,” explains Olga, “and I decided to learn how to identify them to species, and for this I took pictures.” A wealth of biodiversity can be found in these samples, and she says “I [also] constantly find mollusks, oligochaetes, nemtodes, and others in the samples, but most of all I’m passionate about water bears (Tardigrades).” Check out some of her water bear photos here - hopefully she’ll add some more to iNat!
The worm photographed above is in the genus Manayunkia, which is a member of the Sabellidae, or feather duster worm family. These are polychaete worms, and polychaetes are commonly called “bristle worms” due the setae protruding from each segment of their bodies. Many move about freely, like this enormous Alitta brandti, but others like the feather duster worms create a tube in which they reside. Olga says that Manayunkia reach about 5-8 mm in length, and “at the front end there is a corolla of tentacles, with which they breathe. [The] worms live in tubules built from silt or sand particles. Manayunkia live on sandy and silty soils, stones, sponges [and] they feed on detritus. The fauna of polychaete of Baikal today includes only 3 species, conditionally considered to be endemic (http://irkipedia.ru/content/bespozvonochnye_baykala_polihety).” Nearly all polychaetes are marine, so these freshwater species are of definite interest.
Olga joined iNaturalist only recently but says it’s “a very useful idea for collecting information on the global distribution of species. And to me personally, it helps to identify species in the definition of which I’m not an expert...I am very, very glad that the Internet users liked the photo of the Manayunkia so much, and even more so if they became interested in the Baikal Polychaeta itself.”
- by Tony Iwane
- Amazingly, Lake Baikal has its own endemic seal species.
- Like many tiny things, Manayunkia can have a large impact on its environment. For example, Manayunkia speciosa can harbor myxozoans that parasitize salmonid fish.
- Here’s some video of a much larger feather duster worm.
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