Tiny Turkish diatom discovered

24 June 2010

A new diatom smaller than the tip of a pin has been discovered in Turkey , scientists at the University of Plymouth, with the help of those at the Natural History Museum, report this week.

Less than 1/100th of a millimetre in diameter, this tiny alga is not only a new species, but a new genus (the group the species belongs to), too. It is called Clipeoparvus anatolicus and is featured in the Museum’s Species of the day, today.

Diatoms are a group of single-celled algae that have silica cell walls. They photosynthesise and form the basis of the aquatic food chain. All algae help remove carbon dioxide from the Earth’s atmosphere, and this new diatom could reveal clues about environmental change, past and present, too.

The University of Plymouth’s Dr Jessie Woodbridge and Prof Neil Roberts uncovered the new diatom in the volcanic crater lake, Nar Golu, while doing a 3-year study of microscopic algae in Turkey.

‘We don’t yet know much about it,' says Dr Woodbridge, 'but like all algae, it plays a key role in biogeochemical cycles, which remove around a fifth of the world’s carbon dioxide from the atmosphere as part of the carbon cycle.’

Studying the diatoms

‘We brought samples back to Plymouth,' explains Prof Roberts, 'and after some extensive research, and collaboration with Dr Eileen Cox at the Natural History Museum, we realised that it was not just a new species – it was a new genus.’

They compared the new find with other specimens, including those in the Museum collections, as diatom expert Dr Cox explains. ‘Here at the Natural History Museum we have over 100,000 diatom slides, each with hundreds or thousands of specimens, which makes the collection of incredible international importance.

'It’s only by coming here that researchers like Jessie and her colleagues have the opportunity to refer to collections and expertise found nowhere else in the world.’

The team also used microscopes at the Museum, producing scanning electron microscope (SEM) images, such as the one above, to zoom in on the minute detail.

Revealing images

The images revealed Clipeoparvus anatolicus' delicately sculptured silica shell, its tiny size and its short irregular spines, as well as other distinguishing features.

Dr Cox says, ‘This really is a fascinating discovery, because not only is this a new genus, but we’re not even sure exactly where it belongs in relation to other genera.’

Naming and grouping species

Organisms are named and classified into scientific groups (the science of taxonomy) according to species, then genus, which is the first part of the name, in this case, Clipeoparvus. Because this is a new genus, the name was created by the team, where Clipeo means round shield-like shape and parvus means small.

Organisms are also arranged into larger Families, then Orders, Class, Phylum, Kingdom and finally Empire. Scientists don't yet know which Family and Order Clipeoparvus anatolicus belongs to.

Diatom present and past

The new diatom was found living in a crater lake in Turkey and was also preserved in the lake sediments dating back more than 1,500 years. The scientists also found that it had flourished over the last 5 years as the lake water levels dropped by more than 3m.

The team also found that numbers of Clipeoparvus anatolicus had fluctuated in abundance over the last 1,720 years. This means its numbers changed in response to changes in its environment, so it may be an important indicator of environment change, like many other diatoms.

Diatom diversity and abundance

Diatoms are found throughout the world in fresh waters and the oceans, and due to their enormous numbers, they produce more oxygen each year through photosynthesis than the rainforests.

Scientists estimate there may be more than 200,000 species of diatoms, with only about 15,000 named so far. It is unusual to find a new genus and these are more likely to be found in poorly investigated environments or remote locations. But, finding this new diatom shows that, even in accessible places like lakes, there is still biodiversity to discover.

Prof Roberts concludes, 'It is important for science to understand biodiversity and it brings home the delicate balance in managing our environment - changes to which could wipe out species before we realise they exist.'

The new find is published in the latest issue of the journal Diatom Research (2010, 25 (1), 195-212).

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