How to Participate

We appreciate your efforts in helping us, and we want to make sure your time is well spent in finding useful samples. Take a look at this brief guide to get an idea of how to collect rock samples and send them to us. You can find out where you need to go, what to look for, and how to harvest the samples you find. You can also go to the gallery to see other submitted rocks.

Where to Be

We are looking for rocks from extremely dry deserts. If you live near a place such as the Atacama Desert in South America, the Mojave Desert in the southwestern United States, the Gobi Desert in eastern Asia, the Sahara Desert in northern Africa, the Negev Desert or the Arabian Desert in the Middle East, you may be able to help. Take a look at the map to the right to get an approximate idea of where we are interested in finding samples.

What to Bring

When you go into the field to harvest samples, you'll need some basic tools. Make sure to pack all of these:

  • Hammer
  • Permanent marker
  • Zip-loc bags
  • Smartphone (with a GPS app)
  • Water (!)

What to Look For

When you go into the desert, you will see lots of rocks. We are only interested in very particular formations: rocks that have been colonized by microbes. You cannot recognize these from a distance - you will have to break a piece of the rock and take a close look inside to see if it has signs of colonization (see the Rock Reference Library for examples).

Colonization Zone Workshop

What is the colonization zone?

In extremely dry deserts around the world, microorganisms find refuge inside rocks as a survival strategy. The area in the rock where microorganisms are found is called the colonization zone and it is green. Why green? Because some of the microbes in the rock carry out photosynthesis, very much like plants, to make a living. As such, they contain chlorophyll, which as you know, is green. So, looking for the green colonization zone inside a rock is the best way to find out if you rock is inhabited.

What are the types of colonization?

Within rocks, we can define 4 main colonization zones where microbes can be found: (i) the epilithic colonization, where miroorganisms grow on the rock surface and are exposed to the sun, (ii) the endolithic colonization, where microorganisms live inside the rock, underneath the surface, (iii) the hypoendolithic colonization, in which microorganisms are found within the underside of the rock, and (iv) the hypolithic colonization, where microbes are living underneath the rock and are in contact with the soil.

How to Harvest

Depending on what kind of colonization you have, you will want to look at your rock in different ways.

  • Endolithic colonization: microbes are living inside the rock. Start by marking the top of the rock with your marker. Then use a hammer to break off a piece, and check the inside for a green color that might indicate colonization.
  • Hypolithic colonization: microbes are living underneath a rock. Start by marking the top of the rock with your marker, so that we can keep track of how it was oriented in the field. Then pick up the rock and look underneath to check for a green color that might indicate colonization.
In either case, if you find colonization (green layers), take your rock and put it in a Zip-lock bag to prevent contamination. Try not to touch the rock too much - we're studying the microbes that naturally colonize the rock, not the microbes on your skin.

After collecting your rock, you will need to write down the GPS coordinates of the location. If you have an iPhone, open the Compass app, and you will see the coordinates (note: you need to enable Location Services for this to work). If you have an Android device, the easiest way to get the coordinates is to download the app GPS Coordinates. Write down the coordinates in degree-minute-second form (for example, 39°19'51'' N). You should also use your phone to take at least one picture of the rock with its colonization zone showing, and any other pictures you think are relevant. After that, log in to our website and follow the instructions to send us the information.