This shouldn't come as much of a surprise. Since humans absolutely and entirely depend on the oxygen present in the atmosphere, there would be no chance of our survival if it didn't exist. This is not only true of humans, but also of every creature that depends on oxygen. from the tiniest ants to the biggest blue whales.. All would perish. Talking about whales, they would also have one more problem on their hands.. no ocean. The atmosphere blocks tons of harmful rays from the sun and hence shields, the plants from scorching heat. It the absence of the atmosphere, however, oceans would simply evaporate as a result of the extreme heat. You shouldn't expect to find any water, as not having an atmosphere means no oceans, which also mean no water cycle.