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Cactus Alga

Halimeda sp.


The moment I spotted it, I did a double take...Opuntia cactus underwater!!! This flat handfan-shaped green structure looks a lot like the Opuntia cactus. This is a macro-alga (I read it up!!!) According to one report: " These seaweeds can relocate their chlorophyll. At night, chlorophyll might be concentrated in the centre of the segment. As a result, the seaweed may appear white."I spotted it during the day; no wonder it was green.


Growing attached to rocks that were exposed when the tide went out.


Great info plus photo:

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SukanyaDatta 6 years ago

Ha , Ha Leuba! Thanks, .I love teaches me so much in such a fun way.

Leuba Ridgway
Leuba Ridgway 6 years ago

Fantastic spotting and wonderful write-up. Thanks. I thought it was snow in Mexico :) . That is really amazing about the chlorophyll..

SukanyaDatta 6 years ago

Thanks Mark, Of course I had no idea what this I typed in Opuntia sea weed/ cactus alga....and that's how I know what this is. Thanks a lot for your encouragement.

Mark Ridgway
Mark Ridgway 6 years ago

Brilliant find SD !! These look so like a cactus. What an amazing location too. :)

Spotted by

Andaman and Nicobar Islands, India

Spotted on Oct 10, 2014
Submitted on Oct 20, 2014

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