From shallow coastal areas to the deepest ocean trenches, from the tropics to the polar seas, oceanography is an interdisciplinary study of the world's oceans. Physical oceanography (the study of waves, currents, tides, and ocean energy); geological oceanography (the study of the sediments, rocks, and structure of the seafloor and coastal margins); chemical oceanography (the study of the composition and properties of seawater and how they are affected by physical mixing processes and interactions with the seafloor, the atmosphere, and ocean life); and biological oceanography (the study of the composition and properties of seawater and how they are affected by physical mixing processes and interactions with the seafloor, the (the study of marine organisms and their interactions with the ocean environment). These sub-disciplines are strongly related to other subjects such as meteorology/atmospheric science, geophysics, and ocean engineering, and are interconnected. Oceanography encompasses more than just these sub-disciplines. Oceanographers research the water with a range of instruments, and many of these studies involve more than one branch. Oceanographers use ships to collect individual water, sediment, and biological samples (Research Vessels). They use autonomous sampling equipment like buoys and gliders to acquire data on time and space scales that a ship cannot. Oceanographers can acquire a worldwide perspective of some parameters via remote sensing from aircraft and satellites.