Monday, April 23, 2012

Tuesday April 24, 2012: What we are doing here

A lot of what we do here is drive along east-west trending roads stopping periodically to dig shallow holes, collect soil samples, measure the temperature and humidity underground, and turn over rocks.

The western side of the Namib Desert has lots of fog but essentially no rain.  The eastern side has more rain, but less fog.  Here at Gobabeb there is a little of both.

All of us are here to study the bacteria that live in the soil and under rocks, and how they survive such an extreme environment.  Each of us has a different focus:

Professor Don Cowan’s South African team uses a powerful technique called metagenomics which essentially means studying the DNA of whole communities of bacteria probably consisting of hundreds of different species.  You don’t isolate and culture the individual species; you just study the collective DNA of the whole sample.  That way you learn about its genetic diversity; and how its ecology works.

NASA Scientist Chris McKay says “Follow the Water.”  He and his team are interested in whether the microbes are getting their water from fog, rain, or groundwater.  Is the water reaching them by coming down from above, or up from below?  There are chemical and physical techniques you can use to answer these questions.

The University of Edinburgh’s Sophie Nixon wants to know what chemical reactions the bacteria use to live when there is no molecular oxygen (O2) present.  She is especially interested in reactions that use iron.

Like everybody here, I am interested in the cyanobacteria that colonize the undersides of rocks.  How long does it take them to colonize a new surface?  What light levels do they prefer?  Why are some rocks colonized and not others?  That is why I am placing glass and marble tiles in the desert; to see when and if they become colonized by cyanobacteria.

Although we’re here for science none of us are unaffected by the majestic scenery and the presence of herds of big animals running around in the wild.  Yesterday on the road we saw zebras, ostriches, springbok, and warthogs.  I will try to post some good pictures but it isn’t easy.  The animals are very shy of us and they run fast.

No comments:

Post a Comment