[neilep (OP)]

Hello There,

I'm Neil !

As a sheepy I of course serve to make a wonderful natural flotation device. I'm there, ready to save any damsel in distress...
..but check this seaweed out.

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Nice eh ?

It's got lots of bubbly things which I presume is there to make it float !

Is that right ?...and why does it need to float ? and what is the gas inside it that makes it float ?

I would ask my neighbour but I think he's still in orbit ! *le sigh*


Hope to hear from ewe soon.


mwah mwah mwah



Neil
Lover Of Chinese Seaweed (Which is in fact cabbage...did ewe know that ?)
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[RD]

The gas in the bubbles has to be gases produced by the plant, i.e. oxygen (photosynthesis) and carbon dioxide (respiration).
 So the gas in the bubbles will not have the high level of nitrogen which air has (78%).

[neilep (OP)]

The gas in the bubbles has to be gases produced by the plant, i.e. oxygen (photosynthesis) and carbon dioxide (respiration).
 So the gas in the bubbles will not have the high level of nitrogen which air has (78%).

Thanks RD

So, there must be a mechanism for the creation and storage of this gas made by the seaweed. Why does it need to float ?...doesn't it need to be planted somewhere ?

[RD]

The oxygen produced in photosynthesis is made in all plants, so a special gas creation mechanism is not required.
A gas-tight membrane would be necessary to store the gas in a bubble, normally plants have microscopic openings called stoma which would let the oxygen (a plant waste product) escape. So special areas with few/no stoma would be required to create the gas-tight bubbles.

If the plant did not float it would sink to the bottom of the sea where it would receive lttle/no sunlight and die.

Some seaweeds are anchored with a root-like holdfast. Others are free floating.

[lyner]

It's a very 'cheap' way to compete with your neighbours, compared with growing a self supporting stem.