Over 20 years of monitoring microscopic diatoms - single-celled, photosynthesising organisms that can move about - in Blackford Pond, to the south of Edinburgh, recently led to some fascinating new discoveries for RBGE scientist Prof David Mann. In a paper published in the latest issue of the journal Phycologia, David and colleagues name and describe five ‘new' species of Sellaphora, one of them memorably dubbed S. auldreekie (right).
The five ‘new' species of diatom named by David were previously thought to be variations of a known Sellaphora, S. pupula. However, by observing the mating habits of populations found in Blackford Pond, David concluded that at least six distinct species are found there. "The classification of diatoms has always been unclear and has relied on observing outer similarities alone. My theory is that one can apply the basic rule of thumb for higher plants and animals- that individuals would only mate with others from the same species - to distinguish diatom species."
David's groundbreaking approach to the classification of diatoms opens the door to potentially hundreds of new species being named in the genus Sellaphora alone. Though they are a crucial part of aquatic ecosystems and account for one fifth of photosynthesis on the planet, diatoms are poorly understood. David's studies of diatom cultures in the RBGE's labs, in collaboration with Ukrainian scientist Victor Chepurnov, have also led to a more detailed knowledge of diatom sex.