Published on October 1st, 2020 | by David Marshall


Episode 115: Diatoms

Diatoms are a major group of algae found in waters all around the world. As photosynthetic phytoplankton, they are hugely important ‘primary producers’, integral to nearly every aquatic food chain. They are responsible for a large proportion of the world’s oxygen production, with estimates ranging between 20 and 50%.

Diatoms are unicellular plants that produce their cell walls, termed frustules, out of silica. These intricate frustules are what we find preserved in the fossil record and they can contain an absolute wealth of information.

In this interview, Prof. Anson Mackay, University College London, joins to discuss his work on the diatoms from Lake Baikal, Siberia. We learn why lakes are such special ecosystems and what diatoms can tell us about the world through studies of their palaeoproductivity over thousands of years.

Lake Baikal is located in Siberia, Russia, just north of the border with Mongolia. It gets 4.7 stars out of 5, which is very good as far as lakes go.

Lake Baikal is the world’s largest lake by volume, containing almost a quarter of the world’s fresh water. Image: Shamank Rock.
Prof. Mackay has been studying Lake Baikal for the best part of three decades. Image: Research vessel RV Verschagin in dock on Lake Baikal.
Prof. Mackay coring Lake Baikal with a specially designed box corer to retrieve top 10cm of sediments.
In winter, the coring can be done from the surface of the ice.
Longer cores are capable of collecting sediments spanning 130 thousand years.
Dr Mike Sturm and Dr Lena coring from frozen Lake Baikal.
Dr Ginnie Panizzo holding extracted core.
Once the cores are retrieved, the sediments are then cut and analysed. Image: Dr Sarah Roberts and Dr Ginnie Panizzo core slicing.
Aulacoseira baicalensis is a diatom endemic to Lake Baikal meaning it can be found nowhere else.
Cyclotella baicalensis is another endemic species. This view shows just how intricate their silica ‘frustules’ can be.
Celebrating end of successful fieldwork in March 2013.
Prof. Anson Mackay.

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