Today I will be talking about Diatoms! They are single celled photosynthetic algae. Their cell wall is made of silica, which is the same material that glass is made of. They range from 0.5-2mm in size. They are divided into two orders on the basis of symmetry and shape: the round nonmotile Centrales have radial markings; the elongated Pennales, which move with a gliding motion, have pinnate (featherlike) markings. Both of these can be seen at the bottom right of the photo! They exist floating at the surface of oceans, lakes, and rivers producing 20-40% of the oxygen we breath. There are thousands of different species (much debate on exactly how many) of these eukaryotic organisms, each with their own shape and coloration. Truly the snowflakes of the sea. They outnumber any other phytoplankton group (there are cyanobacteria, dinoflagellates, and coccolithophore... google them because they all look amazing). These organisms are very sensitive to changes in their environment and serve as indicators of pollution, which affect their growth rates and abundance.
Originally posted on 9 December 2018
(not my picture)
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