Our two-person team loaded the car with a GPS, a drone, notebooks, sample bags, a trowel and a flat spatula lovingly called a scoopula. Then we drove 30 minutes in our rented truck from Yuma, Arizona, to the Algodones Dunes, a sandy field bordering California, Arizona and Mexico. The day was sunny, with a strong breeze. Turning off the highway, we carefully headed onto a gravelly path that acted as our road.