It's a microbial world

What does life in the Dry Valleys of Antarctica look like?  Well, the food chain is pretty short and is based on bacteria and diatoms.  Bacteria can be found everywhere in the Dry Valleys, but in some areas there is flowing water in the summertime that allows visible growth of microbes.  These pictures show some of the particularly dense areas of a cyanobacteria (photosynthesizing bacteria) called Nostoc (it is the black lumpy one).  This is the organism that originally got us interested in DV research - it fixes nitrogen gas from the air and thus is likely to be providing this important nutrient to the system.  Figuring out the total input of nitrogen from Nostoc has been a major thrust for us over the last few field seasons, but one thing we learned from previous trips is that there are other potential nitrogen fixers that live in the mat with Nostoc.  One of the things we are trying to find out now is what these other potenial nitrogen fixers are doing, where they live and how much they contribute to nitrogen fixing activity.  Some of the other microbes we saw down here are mosses (green in the bottom picture) and Phormidium (the red guy).  Phormidium is another cyanobacteria found in the streams - usually in the center rather than the edges like Nostoc - but it does not fix nitrogen.  One of the things that intrigued us is what might be driving the distribution pattern of Phormidium vs. Nostoc.  For our research, we went out and sampled these mats all over the Taylor Valley and brought those samples back to our tent to process them.  We also set up a shading experiment to simulate what might happen to the mats when summer is beginning or ending (top picture)  More on what we did with all these samples in my next post!

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