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Showing posts with the label Periphyton

Diatom of the month – April 2016: Cocconeis placentula

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by Luca Marazzi* ‘Who’ is it and where does it live? This diatom is monoraphid, that is to say it has a raphe only on one valve, as shown in the figures. Monoraphid species are one of 9 major morphological types of diatoms - the other ones are: centric (like Cyclotella meneghiniana ) , araphid (e.g. Asterionella formosa , which forms star-shaped colonies !), eunotioid (e.g. the beautifully ornamented Eunotia diadema ), symmetrical biraphid (e.g. the slender Navicula lanceolata ), asymmetrical biraphid (e.g. Gomphonema parvulum ), epithemioid (e.g. Rhopalodia gibba , which hosts nitrogen-fixing bacteria as symbionts), nitzschioid (e.g. the organic pollution-loving Nitzschia palea ), and surirelloid (the big Surirella ovalis ) 1 . Like in many other cases, the taxonomy is far from settled though; following recent research, numerous specimens usually named C. placentula should be more accurately named Cocconeis lineata and C. euglypta 2 .             ...

Algae Met a Bear: Algae where you'd least expect them!

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Polar bear! In the EVERGLADES?!?! So how many of you know the poem "Algy"? " Algy met a bear. The bear met Algy. The bear was bulgy. The bulge was Algy ." I think my dad sang "Algy" to me when I was a little tyke, though in my 3-year-old wisdom I must have taken "Algy" as "Algae" and from then on aspired to become a phycologist. Now, some attribute this verse to Ogden Nash, while others chalk it up to Anonymous (that great and varied writer!). And while this verse may be humorous, it's not truly nonsense (though this sentence is). I've seen analysis of Algy and the bear as an allegory for existentialist being (what does it mean "to be"?), while others just say (spoiler alert) that the bear ate Algy. BUT, I think they're all wrong as a result of a translational error where "Algy" should be "Algae" as my 3-year-old self clearly realized. THEREFORE: Looks a little green 'round the edges. ...

The Wonderful World of Diatoms

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I admit that I ended that last post a bit unclear. But diatoms, it should be said, aren’t (or, rather, shouldn't be said since I shouldn't use double negatives. Ah, well.). Not physically, that is; you see, diatom cell walls are made of silica (glass), and that feature is actually incredibly important (not to mention gives rise to beautiful 'micromanipulations' like this one by Klaus Kemp - different colors in part because of different thicknesses of their glass). Diatoms arose between 180 and 225 million years ago – youngsters in the algal world (compare that to the geezer cyanobacteria of 3+ billion – way vintage) – and in so doing utilized an under-used, widely available resource that set them apart. The genealogy (or “systematics”) of diatoms has since expanded to include anywhere from 20,000 to over 1 million species that span almost every aquatic or semi-aquatic habitat imaginable – oceans, lakes, rivers, moss, soil. In those habitats they can be suspended in ...

Exploring the Outer Reaches of the Everglades

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  This post was written by guest blogger Emily Nodine, a PhD candidate in FIU's Periphyton Lab ( http://algae.fiu.edu/research/ ). When people think about today’s Everglades or the “River of Grass,” they generally think of Lake Okeechobee, Everglades National Park, and the canals and water control structures in between.  But the watershed is actually much larger than that.  Lake Okeechobee does serve as the headwaters of the Everglades; prior to human alteration, Lake Okeechobee would slowly overflow southward during very wet periods, forming the shallow, slow-flowing sheet of water that earned it the title “River of Grass.”  Today, the Hoover Dike prevents this and the water flow is strictly controlled, mostly released to the east and west coasts via the St. Lucie and Caloosahatchee Rivers, but also southward to the Everglades through an extensive system of canals and water control structures.  But the water in Lake Okeechobee came from somewhere else, too. Lak...

Three new Everglades diatom species named

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Recently, my colleagues and I named three new Everglades diatom species after much morphological analyses and taxonomic detective work. While the Everglades diatom community may not be as species-rich as lakes in more temperate environments, there are many species waiting to receive a proper name and publication. The reason that so many species continue to be called "species number 17" or "looks like this other species but not quite" is because there just has not been the kind of focused taxonomic research here in subtropical and tropical places in the Western hemisphere. Contrast this to the hundreds of years of research on European diatoms. The Everglades diatom community offers great opportunities for graduate students, like me, to investigate and describe new species! Everglades periphyton with four live cells of  Mastogloia calcarea at 1000x magnification For the FIU News article, click here: http://news.fiu.edu/2013/09/ algae-researcher-names-three- new-specie...