<p>Don’t forget marine geology. Below is some information from the Marine Sea Grant website: </p>
<p>Geological oceanographers study the evolution of the ocean bottom and the nature of the minerals found there. Chemical oceanographers study the chemicals and chemical compounds in the oceans. Physical oceanographers study the ocean as mass in motion, from the gentle movements of ocean currents to the dramatic power of tidal waves.
As many interesting geological features as there are on land, nearly as many exist within, under, and at the boundaries of the oceans. Mountains, valleys, volcanoes, islands, plains, canyons – all exist in similar form in the marine realm. In fact, Earth’s largest continuous mountain chain is the Mid-Ocean Ridge, stretching for over 40,000 miles and rising above the surface of the water in a few places, such as Iceland. The Mariana Trench, located in the central Pacific Ocean, is deeper, by about a mile, than the highest point of Mount Everest. Active deep-sea volcanoes, located along mid-ocean ridges, supply rich mineral deposits and new rock formations on the seafloor. Marine geologists locate the underwater volcanoes by using sonar and acoustic techniques that bounce sound waves off rock formations. They also use remote sensing technology to map the ridges and valleys. It has been written that the ocean bottoms are the most active places on Earth, from a geological perspective.</p>
<p>Conditions at many of these sites make it difficult for marine geologists to visit and study. Before the technological advances of only a few decades ago – piloted submersibles, remotely operated vehicles (ROVs), and programmable acoustic instruments attached to ships – oceanographers could only speculate about the very existence of underwater geological features. Such advances have not only proven the existence of underwater features, they have made it possible to develop accurate maps and detailed, 3-D computer models of the seafloor.</p>
<p>Geological oceanographers study the formations, composition, and history of the seafloor. They examine sediments, including physical characteristics such as size, shape, color, and weight; chemical characteristics, such as composition and how sediments interact with the environment; and other factors, including sediment age, origin, distribution, and transport. By combining their knowledge of marine chemistry and physical oceanography, marine geologists help piece together information about how the Earth formed and how the movement of plates and continents results in events such as volcanoes and earthquakes. Also, marine geologists work with biologists and chemical oceanographers to learn more about historical climate records and animal and plant life by examining sediment and rock cores for fossils and analyzing sediment composition using radiocarbon dating and other methods.</p>