Protective Coating Prevents Dehydration

piles of seaweed are dried out on a beach

Biological Strategy

Sea-wrack

AskNature Team

Image: nz_willowherb / Flickr / CC BY - Creative Commons Attribution alone

Protect From Loss of Liquids

Water is essential to life. Liquids, mostly water, make up 70 to 90% of all living systems, and the loss of even a small percentage can mean the difference between life and death. Living systems must maintain a proper liquid balance, which is especially difficult in dry conditions. To do so, they must control the movement of liquids across their boundaries. Living systems do this using structures or waterproof materials to prevent or slow liquid movement. For example, when humans receive a cut, they must limit blood loss. Scattered throughout the bloodstream are lens-shaped structures that serve to plug the wound.

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Protists

Kingdom Protista (“the very first”): slime molds, giant kelp, red and brown algae

Protists are a numerous, diverse group of organisms that, in the simplest definition, are defined by what they are not. Protists are not plants, animals, fungi, or bacteria. Some protists, like Plasmodium, are harmful parasites that cause malaria. While many are small, obscure, and go unnoticed, others are important foodstuffs. The largest protist in the world, giant kelp (Macrocystis pyrifera), is utilized by humans and marine species for food and shelter.

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Sea-wracks prevent dehydration when exposed to air by coating themselves with a protective mucus.

“Where the coast is not muddy but rocky, trees cannot survive. They would soon be smashed by pounding waves. The only tactic here is to be flexible and ride the thrusts of the waves rather than resist them. And that is what the sea-wracks do. They are algae. Those that live between the tides have to take precautions against being dried out during their twice daily exposure to the air and they do so by covering themselves with a coat of mucus. It is this that makes them so slippery under foot. Some species develop gas-filled bladders in their fronds so that, as the tide sweeps in and out, they rise and fall and remain close to the surface within reach of the all-important light.” (Attenborough 1995:302)

Last Updated August 18, 2016

References

Book

The Private Life of Plants

BBC Books | 21/08/1995 | David Attenborough

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