Sunday, February 27, 2011

Saturday, February 26, 2011

Saturday February 26: The scientific story emerges, and a camel traffic jam

Saturday was a long day driving around the eastern portion of the Empty Quarter looking for good sabkhas.  We didn’t find much there, but now we know.  We took one car, with just Chris, Jon, myself and Arab Youth Venture Foundation staff member Annie Ortiz in it. 

Half an hour away from our hotel, we realized we had taken with us the key to another car which our colleagues needed.  So, we turned around to return the key.  During the hour that followed, driving over familiar roads, we discussed the scientific story that is emerging here.

Part of our purpose in making this trip was to look for hypoliths, which are stones colonized on their undersides by cyanobacteria.  It turns out that the Emirates aren’t good hypolith territory.  There is too much sand, and not enough of the right kind of stones.  We haven’t seen any, except a few very small ones near Jebel Hafeet.

But the salt-loving bacteria that live in the sabkhas here are excellent and interesting.  We humans can drink water that is only about 1/10th as salty as seawater, but seawater itself still feels “fresh” to some of these bacteria.  They can live in water that is a lot saltier than seawater. 

The sabkhas have groundwater a few feet underneath them that is probably fairly fresh.  It appears that the groundwater wicks upwards and evaporates at the ground surface, leaving behind layers of salt crust and brine.  In the top layers, cyanobacteria and halophilic bacteria thrive, protected from ultraviolet light and from drying out by the top centimeter of salt crust.  The translucent salt crust acts like a greenhouse window. 

The pink halophilic bacteria grow in the uppermost layer, with the green algae and cyanobacteria just below them.  Lower down there is a dark layer of bacteria.

Mars probably has salt flats like this.  Nothing can live on the surface of Mars because of the harsh ultraviolet light.  But, a centimeter of salt crust is all it takes to block the ultraviolet light, while allowing plenty of visible light to be transmitted.  So, this kind of environment is a good place to look for life on Mars.

None of this makes good photographs, so enjoy the photos I am putting here of us (with Annie at the wheel, as always) stuck in a camel herd.

Saturday February 26: Fun with the Sun

Today was long and busy, and I've run out of time to describe or post photos of what we did and what we learned.  Tomorrow I will catch up. 

Meanwhile, enjoy these sunset pictures.

Friday, February 25, 2011

Friday February 25: Camels

Our hotel is next to the Madinat Zayed Camel Racetrack and Training Grounds.  All day long trainers are coming and going, leading strings of camels to and from the track.  They run around the track accompanied by a pace car.   This is the most important racetrack in the Emirates.

We have seen thousands of camels in the rural areas around Liwa, but these are more beautiful because of the tack they wear.  

I could watch them all day.

Friday February 25: We go on TV

Today was press day.  We went back to the big sabhka near Liwa and met a crew from Abu Dhabi Media Incorporated, the national TV station.  We showed them our research and they interviewed Chris, Jon, myself and Hussain. 

I told them that NASA placed a priority on including students in research, and that in addition to helping prepare the artificial hypolith experiment, my students were following our research on this blog.  I also talked about our interactions with yesterday’s students from Abu Dhabi, and how we expected more students to visit us on Sunday. 

We were on the air at 8 and again at 11 tonight, and we were also featured today in a page 3 article in the Gulf News.

Jon cut a big plug out of the salt crust that shows the different layers of bacterial cells; brown, green and pink.  It looked like a big sandwich.  We left Liwa and drove out onto the gravel plains, looking for hypoliths but we did not find any.  There was too much sand, and none of the right kinds of rocks.  For astrobiologists, the sabhkas are the stars of the show here.

I found this skull of a goat, I think.

Thursday, February 24, 2011

Thursday, February 24: Dhafeer Fort

We stopped at Dhafeer Fort on the way home.  There are a lot of little forts like this one in the area of the Liwa Oasis.  Most of the old buildings here are forts. 

People around here mostly lived in tents in the old days, or small homes made out of palm thatch.  Those homes have not survived.

Thursday, February 24: A school field trip to the Empty Quarter

This morning we went to the big sabkha (salt flat) that we found last night along the road to Tel Moreeb.  We were joined by about 30 students and teachers from Cambridge High School in Abu Dhabi, an international school.  The students were from all over:  Germany, New Zealand, Pakistan, the Emirates, etc.  They were very engaged and they helped us collect some methane samples and make some measurements at this very interesting site. 

There was standing water in puddles, colored by pink and orange halophilic bacteria.  More bacteria, mostly green and pink, live in layers just under the salt crusts.  They are using the salt crust like a greenhouse window.  The salt lets some light through, but not too much.  It also protects against desiccation, and limits competition from other organisms.

After collecting our samples and saying goodbye to Cambridge High School, we continued south on this dead-end road into the Rub Al Khali, also known as the Empty Quarter.  This is the world’s largest area of continuous sand dunes, stretching about 600 miles into Saudi Arabia.  Jon Rask and I climbed a dune, and the heat was so intense it was hard to breathe.  It was at least 30 degrees F hotter on the dune than it had been on the sabkha, and it was warm enough on the sabkha.