Virtual Field Trip to the Florida Keys

Halimeda Gallery

The thumbnail images below link to larger versions of the images. All but one of the photographs were taken looking down through very shallow water on Middle Torch Key (Location 11). They show living, and recently dead, examples of the calcareous green alga Halimeda, and other algae.

Halimeda is an important carbonate sediment former. It has a segmented form, and on death it breaks down into flat plates with the size and shape of cornflakes (or perhaps Special K!), producing a very distinctive coarse bioclastic sand.

Penicillus, another common tropical green calcareous algae, contains needle shaped crystals of aragonite just a few microns long in its soft tissues. It is an important source of carbonate mud.

Note how the algae are streaming in the direction of the tidal current.

Halimeda Halimeda and fish Halimeda in current Halimeda in current Halimeda
Halimeda Halimeda Halimeda in current Dead Halimeda sample

Penicillus

Penicillus

For further information on Halimeda and other green algae, study the following web sites: