oceanography

Oceanography is the scientific study of the oceans and their processes. It encompasses the physical, chemical, biological, and geological aspects of the marine environment and the interactions between oceans, atmosphere, land, and cryosphere. Oceanographers seek to understand ocean circulation, waves, tides, climate, marine ecosystems, seafloor geology, and the role of oceans in Earth’s system.

The traditional divisions are physical oceanography, chemical oceanography, biological oceanography, and geological (or marine geology) oceanography, sometimes collectively termed the four major branches. Interdisciplinary research areas include paleoceanography, which studies past oceans, and the chemical or physical processes such as nutrient cycles and carbon chemistry that connect the ocean to the atmosphere and biosphere.

Methods used in oceanography include ship surveys, underwater vehicles, moorings, buoy networks, and satellite remote sensing. In situ measurements of temperature, salinity, currents, dissolved gases, and biological activity are combined with laboratory analyses and numerical models to understand ocean behavior and predict future states. Global observing systems, such as autonomous Argo floats, monitor temperature and salinity throughout the world’s oceans.

Historically, early exploration and 19th-century expeditions laid the foundations for oceanography, which expanded into dedicated research institutions in the 20th century. The field supports weather and climate prediction, maritime operations, fisheries management, and environmental monitoring, and it informs policy decisions on marine resource use and environmental protection.

Oceans play a central role in climate regulation, biogeochemical cycles, and the habitability of marine life. Oceanography addresses challenges such as ocean acidification, sea-level rise, and the response of marine ecosystems to human activity, contributing to scientific knowledge and practical decision-making.