Natural History Museum

Lake Myvatn

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Myvatn is a shallow, eutrophic lake in north Iceland. The name means Midge Lake and the area is inundated with them every summer. Luckily, when we visited the midge swarms were of non-biting chironomid species (it’s very handy traveling with an entomologist!).

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Besides being beautiful, formed from volcanic action and full of wildfowl, Lake Myvatn is also famous for balls of algae known as lake balls, marimo (Japanese) or kúluskítur (Icelandic). These are spherical colonies of filamentous algae (Aegagropila linnaei) which are thought to form when algae living on the rocks are torn off and are rolled around in the lake currents. Rolling helps to keep the ball clear of debris and mud so the colony stays velvety green.

 

Tantalising greeness on the lake bed
Tantalizing greenness on the lake bed – could they be algal balls?

Recently, however, lake balls have been vanishing from Lake Myvatn as sediments begin to silt over the the lake floor. They can be seen in aquaria in a few places in Iceland, I hope they will still survive in their famous lake home too.

Lake balls at the Natural History Museum of Kópavogur
Lake balls at the Natural History Museum of Kópavogur
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Seaweeds Online

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The Natural History Museum after dark
The Natural History Museum after dark

Recently I was lucky enough to go to the Natural History Museum in London for the launch of their Seaweed Collections Online. Jane Pottas and Jo Wilbraham have spent the last year collecting images and information from 14 different institutions aiming to make seaweed data from regional herbariums more accessible (see the RBGE write-up here).

Seaweed Collections Online front page
Seaweed Collections Online front page

The team selected aound 150 different species of seaweed from the c.650 species found around the UK. Species were selected for reasons such as their conservation status (rarity), if they provide an ecosystem service (such as an important habitat) or if their distribution is changing (perhaps through environmental change).

Peacocks tail
Padina pavonica
Green sponge ball
Codium bursa

   430 images of specimens of seaweeds which were collected between the 1840s and 1964 were photographed from the Manchester Museum collection for the project and are now available through the online catalogue.

Bonnemaison's Hook Weed
Bonnemaisonia hamifera
Laminaria digitata
Laminaria digitata