Once in a while we send a bathyscaphe or two to the deep to explore the oceans bottom and the lifeforms there. The conditions there are unsuitable for us, and it takes a good deal of effort to make those expeditions. The strange lifeforms in the deep observe the occasional spherical objects that briefly enter their habitat and then mysteriosly disappear. If our science advances enough, we'll establish a research station there, and maybe even a colony if we find something valuable on the bottom.