debor042

by Luca Marazzi* ‘Who’ is it and where does it live? This diatom is a symmetric biraphid species, i.e. it has a raphe on either valve allowing it to move sliding on substrata. Mastogloia calcarea was ‘discovered’ / described by Sylvia Lee during her PhD research at Evelyn Gaiser’s lab at FIU; it is similar to M. smithii and M. lacustris , common freshwater species in this predominantly marine genus. This new species typically lives in karstic wetlands of the Caribbean region (Mexico, Jamaica and Belize) and in the Florida Everglades, as compared to the temperate zones where M. smithii and M. lacustris live and are found 1 .                                       Mastogloia calcarea in valve (top) and girdle (bottom) view ( http://westerndiatoms.colorado.edu/ ) 1 ; scalebar = 10  µ m .                           ...

Failing better   Rather than talk about my research directly, I’d like to use this blog post to talk about something much more personal and important: the F-word. I would put forward that to be a PhD student almost inevitably forces a confrontation with an unmistakable, devastating, and utterly confounding acquaintance with Failure.    For everyone it will take a different form, and have its own timing, like the boogie man under a child’s bed. For me Failure loomed large over summer of 2014.  At the point when I became confident that I was ready to start generating publishable graphs – that was when I noticed things starting to get dark. One week’s work culminated in a failed experiment, then another. There were the stupid mistakes. There were the skills that I thought were good enough, and weren’t. And then there were the experiments that had to be written off to trial and error, as I adapted a common experimental approach to my particular samples.  Again and a...

by Luca Marazzi* ‘Who’ is it and where does it live? This centric diatom’s c ells are drum-shaped, the valve diameter and the density of marginal striae are highly variable. Cyclotella meneghiniana   is a rather cosmopolitan species; in tropical freshwaters, it is associated with various water depths and salinity 1 , and, in temperate regions, it is a typical planktonic taxon in the late summer-autumn 2 . In North America, this species can cope with a wide range of conditions, for example from freshwater to saline waters in the Great Plains lakes 3 . a)                                                                         b) Cyclotella meneghiniana , with a) chloroplasts and b) silica frustule after ‘chemical digestion’. Source :  http://fcelter.fiu.edu/data/database/diatom/index.htm ...

by Luca Marazzi* ‘Who’ is it? The genus Gomphonema includes numerous species growing on mucilaginous stalks. These diatoms are a symmetrical biraphid, as the bottom part is usually longer and thinner than the top part and they have two raphes, narrow slits that allow them to move over surfaces . Yes, there are diatoms that perform photosynthesis, move and even eat organic matter ! G. parvulum is on the lower end of the size spectrum for the genus ( length from 15 to over 100 µm and width between 5 and 15 µm ).                                      Gomphonema parvulum , partially    obstructed by Eunotia , in a sample  from the Florida Everglades .          Source : Tobias and Gaiser, 2006 G. parvulum and stalks in a sample from Japan; cell body: 48 µm long, 10 µm wide.  Source : http://protist.i.hosei.ac.jp...

by Luca Marazzi* ‘Who’ is it? Tursiocola ziemanii is one of three new species described by FIU’s Dr. Thomas Frankovich and colleagues in a recent paper in Phytotaxa , a journal dedicated to the publication of discoveries on the taxonomy of plants, algae, mosses, lichens and fungi. The name was chosen to honor Dr. Joseph C. Zieman (1943–), in recognition of his generous support of diatom research in, and contributions to our understanding of, Florida Bay. A manatee in South Florida. Source : http://eyeonmiami.blogspot.com/2014/05/did-i-see-manatee-dying-yesterday-by.html Scalebars: a. 5 µm; b)10 µm; Length Range : 20-61 µm;                           Width Range : 2.4-5.2 µm; Striae in 10 µm : 22-25 Scanning electron microscopy photos of Tursiocola ziemanii in a) valve or face view and b) girdle or lateral view . Source : Frankovich et a...