Can Seaweeds Survive the Frost and Snow?
Yesterday I was crunching on frosty kelp, today the seaweeds are limp and wet again, having defrosted in the sun. It's a lot for seaweeds to cope with, or is it?
In reverence to seaweed, and in celebration of the 'proper' snow we had 2 weeks ago (the first time in 10 years here in west cornwall!), I thought I'd write about seaweeds, snow, frost and freezing temperatures.
Do they like it? Can they survive? And, if they can, what are their secrets?
Frost catches a moment in time, and literally, freezes it, the effect is beautiful, though what is the impact for the weeds?
Firstly, seaweeds exist across the world, in vastly varying temperatures and conditions, from 50 metre long kelps, to microscopic organisms to seaweeds that never emerge above the water's surface, to ones that are exposed to the sun, air and being dried out for more than 6 hours every day.
Each species of seaweed is suited to particular environments. Deep sea seaweeds (these are sub-tidal and never come above the sea's surface) are used to more constant temperatures, while inter-tidal ones (which get exposed twice a day at low tide) are built to sustain almost extreme changes in temperature.
'Most seaweeds would be killed if frozen. However high concentrations of tissues salts and organic solutes in the seaweed's cells lower the freezing points.'
Basically, seaweeds have in-built anti-freeze which protects them from freezing.
In reality, this means that Bladder wrack (top image) can cope with -40° C for months, Egg wrack (above) can go to -20° C and some of the laver species (below) can remain unscathed at temperatures as low as -70°C for 24 hours or so, as well as cope with rather high temperatures in the hot sun.
I feel hot and cold just thinking about it.
My awe of these millions of years old organisms increase with this knowledge. Furthermore, seaweeds also work together to protect each other - they live layered on top of each other, which means just the top layer freezes and the lower seaweeds are kept at a more tolerable temperature.
Similarly, emperor penguins, which survive some of the most harshest conditions on earth huddle together to keep warm. They congregate in groups, sometimes in thousands, and those on the outside of the huddle protect those on the inside, and between them they circulate so no penguin is continuously on the outside. Of course, like seaweeds, penguins body is suited to the environment, yet working together is essential for them to survive extreme temperatures.
Here's to the beauty of the snow, the amazing science of nature, and a thankful heart for having warm wellies to go and forage for those seaweeds in.
Images courtesy of; loriedarlin.tumblr.com, daily mail, Pam Collins and 500px.com