|
Corallinales (Coralline seaweed)
Copyright © 2007 Jan Holmes
This order of red seaweeds is composed of several genera that have a hardened coral-like appearance caused by the calcium carbonate, magnesium carbonate or strontium carbonate taken up within their outer cell walls. During the time of Linnaeus, the Swedish botanist, they were actually identified as corals. The calcified armor gives these seaweeds protection against grazers.
Species display two different morphologies; encrusting (resembling dried spilt Pepto Bismo) or upright branches arising from an encrusting base. In branched species, the stone-like segments are separated by flexible uncalcified joints allowing branches some mobility. Segments can be flattened or cylindrical and range in size from .5 mm. to 15 mm. (0.6 in.) along the widest axis. Branching patterns are diverse among species from chunky and chainlike to feather-like construction.
Encrusting species can be found on rocks, other seaweeds and mollusk shells. Depending on species the crusts are from .5mm. to 5 mm. thick and up to 40 cm. (16 in.) in diameter. Colors of both morphologies range from bright pink to purplish-red. Reproductive structures of corallines are located in cavities (called conceptacles), which often appear as bumps on the surface of segments or crusts. After spore release, areas around the conceptacles may be whitish. The coralline seaweeds are among the longest lived (to ~50 years) and occupy some of the deepest habitats of all photosynthesizing organisms.
This
page was created by Jan Holmes on 1/25/07.
|
