Marine Diatoms from Ibicui beach, Rio de Janeiro. 
by Roland Mortimer, Brazil

Thanks to the articles produced by Jan Parmentier and the Dutch Club (see footnote) I became interested in studying marine diatoms for the first time in my life. A friend of mine who dives and hunts fish as his hobby, kindly brought me samples from different sea depths in wine and beer bottles. He (Osman) and his wife Célia, apparently barbeque the fish he catches and obviously drink a lot of wine with it, hence the enormous supply of wine bottles. I was amazed at the diversity of species in such a small sample of water simply collected as a 'scooped up' sample.

The sea at this time of the year is at a temp. of about 19ºC, and the sunlight is reasonably constant and bright, excellent for diatom growth. Although most diatoms are fairly cosmopolitan and most species can be found almost anywhere, they have become adapted to their warmer environment and do pretty well in it, even at a depth of seven meters.

Jan suggested I observe the diatoms in a living state first before cleaning them of their protoplasts. He was absolutely right, they are really much more beautiful alive and give much more enjoyment than looking at an empty mounted frustule. Here are just a few of the many photographs I took of the multitude of species from this beautiful area on the Southern coast of Rio. I am very grateful to Jan for his help in identifying these specimens and also for his encouragement.


Editor's footnote: Jan's articles on marine diatoms and other articles on diatoms can be found in the Micscape Library by typing in diatoms in the Search facility. Library link below.

Comments to the author Roland Mortimer welcomed.

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Published in February 1999 Micscape Magazine.

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