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Diatom of the month – October 2016: Brachysira brebissonii

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by Charlotte Briddon*  Brachysira brebissonii (formerly known as Anomoeoneis brachysira ) is a freshwater, benthic diatom. It is widespread in lakes and rivers from the Arctic to tropical and temperate regions. In 1981 the Anomoeoneis and Brachysira genera were separated, as two sets of longitudinal ribs were observed in Brachysira specimens, one surrounding the valve (marginally at the junction of valve face and mantle), and another composed of two straight ribs, discontinuous in the central area that border the raphe , which the genus Anomoeoneis lacks.               Brachysira brebissonii   (photo   taken by Paul Hamilton at Egg Harbour Lakes, New Jersey, United States; see  Hamilton, 2010 ) . Case study of Tasik Chini I have chosen this diatom because it has played a meaningful role in aiding our understanding of past and current environmental conditions/water quality at Tasik Chini, (a flood pul...

Diatom of the month – September 2016: Aulacoseira granulata

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by Luca Marazzi* Last week about 800 ecologists from 72 countries, including myself, attended and presented their research at the 10 th INTECOL Wetlands conference in the beautiful city of Changshu (2 hrs west of Shanghai). Before this event that takes place every four years (in 2012 we were in Orlando for INTECOL 9 ), I was honored to give a long seminar on my work on the algal communities of the Okavango Delta and Everglades at the Nanjing Institute of Geography and Limnology (NIGLAS) of the Chinese Academy of Sciences. I was invited to do that by my friend Xuhui Dong (we studied together for our PhD at the UCL Environmental Change Research Center in the UK). Xuhui and his colleagues recently conducted a paleolimnology study of several floodplain lakes along the mighty Yangtze River (Dong et al., 2016), where they found large numbers of Aulacoseira granulata [ (Ehrenberg) Simonsen 1979] , which is therefore our September diatom (a belated post). ...

Diatom of the month – August 2016: Didymosphenia geminata

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by Luca Marazzi* Many algae are able to form blooms, sometimes releasing dangerous toxins for aquatic organisms and people. Cyanobacteria are most infamous for producing blooms such as those ongoing in Florida's coastal waters , but other algae, including diatoms, can create such vast colonies too. The large ( 100,001-1,000,000 µm 3 ) asymmetrical biraphid Didymosphenia geminata , or colloquially ‘didymo’ is one of them; it attaches to stones in rivers by stalks (made of mucopolysaccharides, long chains of sugar molecules)   that can be 1 m long! Didymo is invasive in Argentina, Chile, and New Zealand, where this video was released in 2008 to inform the fishing community that they should clean and dry all their gear to avoid spreading this species to other water bodies. Fig. 1.   (top)  Didymosphenia geminata ( scalebar = 10 µm ; p hoto by Mart Schmidt ); (bottom)   n umerous cells and mucilage stalks from South Boulder Creek (November 2011) - c redit...
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  The Peril of Peat: Sea Level Rise in South Florida: Part 1 Post by: Ben Wilson      Ben Wilson having some fun in the mud I love mud. Seems like I have for a long time now. It’s squishy and smelly, and once you get a little bit on you, you might as well go all out. I’m lucky in that the two most recent places I’ve lived, coastal Alabama and now in Miami, have had ample areas for me to get my mud fix. However, over the past century those areas have been dramatically decreasing, and given current and future climate change, they may disappear at an even greater rate. Over the next two blog posts, I will tell you how human development has altered water flow in the past, further exacerbating the problem of today: sea level rise. In order to save the mud, we must first look at what caused this problem in the first place. Drain, baby, Drain Whole books have been written on why and how the Everglades have been modified and manag...

Diatom of the month – July 2016: Nitzschia amphibia

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by Luca Marazzi* Nitzschia amphibia belongs to the nitzschioid group : its v alves are symmetrical to both apical and transapical axes, and taper to bluntly rounded apices ; the raphe is well developed near the valve margin, and enclosed within a canal 1 . The original description was made by Albert Grunow in 1852, when the US President was Millard Fillmore, the  last one not to be affiliated with either the Democratic   or   Republican party . This is how ‘old’ are some of the species names of algae and other organisms that persist to this day, while new species are continuously described at an increasing rate. Grunow was one of the eight most ‘profilic’ algal taxonomists who described more than 1,000 species during their career, the others being Kützing, Gottfried, Hustedt, Agardh, Harvey, who worked in the 1800s, and Lange-Bertalot (the only one still alive and active ) and Skvortsov in the 1900s 2 . Fig. 1.   a)  Nitzschia amphibia  in valv...