Sea tomatoes

In the southwest corner of Greenland, where the tundra is dotted with small lakes, scientists spied something unusual beneath the surface of the ponds: Piles of giant colonies of toxin-producing Nostoc bacteria, each colony a jelly-like, spherical blob, some as big as softballs.

Greenlanders call them sea tomatoes.

“These are really slow growing,” biologist Jessica Trout-Haney of Dartmouth College told me. “Some of the big ones are 25 years old.”

Not much else can survive the harsh conditions of the lakes, Trout-Haney said, where organisms must contend with the annual cycle of freezing and thawing and periods of intense sunlight in summer and equally profound under-ice darkness in winter.

That lack of ecological competitors might explain why sea tomatoes can survive for so long in Greenland’s Arctic lakes, Trout-Haney said.

To read more about Trout-Haney’s research on sea tomatoes and Arctic lakes, check out the article I wrote for Eos.org last week.

Lakes and ponds are scattered across the Arctic landscape near Kangerlussuaq, Greenland, where Trout-Haney and her colleagues spotted sea tomatoes growing on lake bottoms.  (Image by Miss Copenhagen via Flickr; creative commons license)

Lakes and ponds are scattered across the Arctic landscape near Kangerlussuaq, Greenland, where Trout-Haney and her colleagues spotted sea tomatoes growing on lake bottoms. 

(Image by Miss Copenhagen via Flickr; creative commons license)