Much of our recent research has focused on the sediment surface in stream ecosystems. The stream bottom (or benthos) is where most stream organisms live (e.g., invertebrates, algae) and where those organisms interact with toxic chemicals that might be in the sediments. There are dramatic changes in chemical and biological conditions as you go vertically from the water in a stream into the sediment. For example, stream water is often fully saturated with dissolved oxygen but within a few millimeters into the sediment all of that oxygen is gone. Small changes in the depth to which oxygen penetrates into the sediment can make a big difference in how many elements cycle in the stream. Standard sensors cannot measure at this small scale, but Unisense makes the very tiny sensors that can measure at a µm scale.