Tag Archives: Nitrogen fixation

Ocean Deserts: it’s a hard life in the tropics, but not if you’re small

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Subtropical gyres are an extreme environment that covers approximately 30 % of the planet’s surface

Think of an extreme environment where life survives in the ocean. What springs to mind? The mind boggling pressures and eerie quiet of the deep-sea perhaps? Maybe the icy environments at the poles? Possibly even an estuary, where organisms are flung from one salinity extreme to the other on a daily basis. There is another extreme environment though, one which few of you probably even considered, one that covers about 30% of the planet and is currently expanding under the influence of climate change: large swirling systems of rotating currents that occur in the centre of oceans known as subtropical gyres.  Continue reading Ocean Deserts: it’s a hard life in the tropics, but not if you’re small


Chalk talk: Coccolithophores


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If you read my previous post on the interesting article about coccolithophore species-specific growth responses to environmental change, you may have been left wanting to know more about coccolithophores in general.  I don’t blame you.  Coccolithophores are pretty awesome. Continue reading Chalk talk: Coccolithophores

Collecting snow in the tropics

R/V Atlantic Explorer at sea

After 2 months of packing, planning, prepping, and fretting, I finally boarded a plane to Bermuda in mid August to take part in a research cruise aboard the R/V Atlantic Explorer. This was set to be the third and final research expedition of my PhD, and I had firm plans to tie up some loose ends from previous sampling and to [hopefully] confirm a few hypotheses I’ve been juggling about for the past year. Like any research expedition, we faced a few hurdles with engine troubles and impending tropical storms, but managed to leave port only 2 days late, and were able tack on an extra day of sampling on the end to make up for lost time. All in all there was no harm done, except maybe to my ever-dwindling research training and support grant, which certainly took a few hard knocks with flight changes. Continue reading Collecting snow in the tropics

Marine nitrogen fixation: the players

This is the second of two articles written by Elizabeth Sargent on the marine nitrogen cycle; the first article covered some of the basics and can be found here

A trichodesmium 'puff'. Oh, and watch out for this image in the April version of Scientific American

There are three main groups of nitrogen fixing organisms in the ocean: filamentous, heterocystous, and unicellular diazotrophs. The unicells are relatively new to the research scene (discovered in 1998), and are difficult to image due to their size, distribution, and our lack of knowledge about their lifestyle. I have some epifluorescent microscope images of unicellular diazotrophs, but you can get a good idea of what that looks like by picturing the night sky; it’s a whole lot of darkness and some tiny yellow dots. Continue reading Marine nitrogen fixation: the players