Hi all! So in place of actual presentations, which we ran out of time for because there are just so many more interesting/informative/educational/exciting/enticing things to do on this island, we are just writing blog posts about our carbonate organisms. Mine is forams, so brace yourself for a wild ride throughout the water column! (Well, mostly on the seafloor.)
Foraminifera, usually called forams, are protists with calcium carbonate shells, also called tests, that encase them. They are found throughout the ocean, but roughly 99% are benthic, meaning that they reside on the seafloor. The 1% (hahaha) are lucky enough to move throughout the water column, which is known as being planktonic. (Don’t worry though, the 99% make up for it by having all the cool shell forms.)
There are about 4,000 species of foraminifera. You can do the math, but 40 of ’em are planktonic and the rest are benthic.
Planktonic forams are generally globular.. they look like globs of translucent stuff stuck together… and, surprise surprise, you will find more and more planktonic forams as you get deeper in the ocean.
Benthic forams are all those who are stuck on the seafloor. Their tests range from agglutinated to calcareous. Agglutinated forms are those whose tests are made of any random piece of calcium carbonate they can find, all cemented together. Calcareous forams’ tests are made of calcite crystals ~1 micrometer big. Calcareous tests range from hyaline, meaning translucent with little perforations, to porcelaneous, meaning white, opaque, and lacking in perforations.
Benthic forams’ tests are indicators of where they reside in the ocean. An agglutinated foram will indicate intertidal marshes and similar habitats, whereas porcelaneous forams are usually found in shallow tropical environments. Hyaline forams are generally found in deeper water.
They’re useful for all kinds of things… they can be dated, so they help determine ages of rock formations, and they will give indications as to past climates. They are great for paleooceanography, which deals with properties of oceans in the past.