Earth's connected saltwater system
Ocean
The ocean is the vast, continuous body of salt water that regulates climate, supports biodiversity, drives global cycles, and connects ecosystems, economies, and coastal communities around the world.
What the ocean is
The ocean is one connected system that includes five named basins: Pacific, Atlantic, Indian, Southern, and Arctic. Although maps divide them, water, heat, nutrients, and life move across all of them continuously. This connectedness is why ocean change in one region can influence weather, ecosystems, and economies far away.
How the ocean shapes climate
The ocean stores and transports enormous amounts of heat. Currents redistribute energy from equatorial to polar regions, while evaporation and heat exchange influence winds and rainfall. The ocean also absorbs large amounts of carbon dioxide, which helps moderate atmospheric warming but increases acidification stress for marine organisms.
Life and biodiversity
Marine ecosystems range from coastal estuaries and coral reefs to deep-sea plains and hydrothermal vents. Plankton form the base of many food webs and contribute significantly to global oxygen production and carbon cycling. Biodiversity in the ocean supports fisheries, tourism, medicine research, and ecological stability.
Human dependence
People depend on the ocean for food, trade routes, energy, and livelihoods. Major cities and ports are concentrated near coastlines, making ocean health closely linked to economic resilience. Shipping, fishing, offshore industries, and coastal infrastructure all rely on stable marine conditions.
Pressures and change
The ocean faces warming, acidification, deoxygenation, overfishing, plastic pollution, and habitat loss. These pressures can interact, making ecosystems more vulnerable to shocks such as marine heat waves and severe storms. Managing these risks requires local action and international coordination.
Why it matters
Ocean systems influence weather, food security, biodiversity, and long-term climate outcomes. Understanding the ocean is essential for planning coastal adaptation, protecting ecosystems, and sustaining economic systems that rely on marine resources. In practical terms, ocean science is now a core part of climate and development strategy.