Chapter 15 - Oceanography

Modern Oceanography The Challenger expedition investigated ocean currents, water temps, seafloor sediment, topography and marine life This expedition used bottom dredges, nets, and other tools to get the data The German ship the Meteor was the first to use sonar in the 1920’s

Advance Technology The Topex/Poseidon satellite constantly monitors ocean surface temps, currents and wave conditions

Origins of the Oceans There are geologic clues that indicate the oceans have been here since the beginning of geologic time Approximately 4.6 billion years ago

Where did the water come from? Scientists hypothesize the oceans came from 2 sources When comets impact Earth, the impact releases water The other is volcanism

Volcanism During an eruption gases are released that are mainly composed of water vapor and carbon dioxide Shortly after the formation of earth there was an episode of massive, violent volcanism This released a lot of water vapor and carbon dioxide As Earth’s crust cooled the water vapor condensed into the oceans

Comets Comets are composed of ice and rock