david gallo, and david souci, david, the silt that is supposedly underneath here will that interrupt the side sonar scanner? >> i don't think silt will be a problem. we always have to worry a bit about sediment kicking up. it would happen certainly not to the level it would impact the sonar search -- >> and the environment, we talked about this a little during the break. the environment at these kind of depths under the water, it is a whole other world. >> it is a completely different world that nobody has a concept of. 50% of the ocean is above that. >> you see species down there you don't see anywhere else. >> all sorts of life forms, you don't see underwater rivers -- >> what is an underwater river.