GEL 109L Bahamas Lab
Organisms produce a
large volume of carbonate sediments, so it is important to know what is living
in different carbonate environments. James Bishop has assembled these links to
the organisms he observed in areas where he collected the Bahamian sediments
you look at in this lab. Use these photos to help you interpret the sediments.
Organisms found in modern carbonate environments (e.g., the Bahamas)
· Mollusk (clam) **Scroll to the
bottom of the page. The last four
photos of shells are examples of this type of organism.
is a living (or recently living) coral
with dark spots disease. This coral is colonial, with a coral animal
living inside each little cup-like polyp on the surface. Coral sediment
often appears porous due to these little calcareous cups or polyps.
site has some lovely photos of corals
(the 3rd, 4th, and 5th photos).
are black sea urchins which have calcareous spines that can be
reworked into sand. Diadema themselves also excavate into hard surfaces,
breaking down reefs and hardgrounds into sand.
- Homotrema rubrum
is an encrusting foraminifera. It can be reworked into carbonate sand
grains which are often colored pink. Scroll down to Figure 3. There is
also other useful information on this page about reef-forming organisms.
coralline (or calcareous) red algae
is a calcareous green algae which is rooted into the sediment and
disaggregates into carbonate sand
following 4 photos links are for calcareous green algae which are rooted
into the sediment and disaggregate into carbonate mud.
meadows (here comprised of Thalassia)
can baffle wave energy, allowing for the deposition of muds and creating
environments favored by foraminifera, snails, and clams.
sea fan is a soft coral or Gorgonid
, which has neither a calcareous skeleton, nor photosymbionts.
Gorgonids like to attach to firm substrates with high energy, such as
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Sedimentary Photos Page
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