Wading Through Research

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 .         ...

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.  Ag...

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/...