In the 200-plus years since the industrial revolution began, the concentration of carbon dioxide (CO2) in the atmosphere has increased due to human actions. During this time, the pH of surface ocean waters has fallen by 0.1 pH units. This might not sound like much, but the pH scale is logarithmic, so this change represents approximately a 30 percent increase in acidity.
Ocean & coasts
While there is only one global ocean, the vast body of water that covers 71% of Earth is geographically divided into distinct regions. The United States recognizes five named ocean basins: Arctic, Atlantic, Indian, Pacific, and Southern.
The ocean and large inland lakes play an integral role in many of the Earth's systems, including climate and weather. More than 50% of all species on Earth are found under the ocean and the ocean helps sustain human life above the water by providing 20% of the animal protein and 5% of the total protein in the human diet. In the United States alone, there are over 95,000 miles of shoreline. More than half of the U.S. population lives within 50 miles of the coast in the narrow area of land known as the "coastal zone."
Ocean water is on the move, affecting your climate, your local ecosystem, and the seafood that you eat. Ocean currents, abiotic features of the environment, are continuous and directed movements of ocean water. These currents are on the ocean’s surface and in its depths, flowing both locally and globally.
Each year, billions of pounds of trash and other pollutants enter the ocean. Where does this pollution come from? Where does it go? Some of the debris ends up on our beaches, washed in with the waves and tides. Some debris sinks, some is eaten by marine animals that mistake it for food, and some accumulates in ocean gyres. Other forms of pollution that impact the health of the ocean come from sources like oil spills or from accumulation of many dispersed sources, such as fertilizer from our yards.
Oil is an ancient fossil fuel that we use to heat our homes, generate electricity, and power large sectors of our economy. But when oil accidentally spills into the ocean, it can cause big problems. Oil spills can harm sea creatures, ruin a day at the beach, and make seafood unsafe to eat. It takes sound science to clean up the oil, measure the impacts of pollution, and help the ocean recover.
Tsunamis are just long waves — really long waves. But what is a wave? Sound waves, radio waves, even “the wave” in a stadium all have something in common with the waves that move across oceans. It takes an external force to start a wave, like dropping a rock into a pond or waves blowing across the sea. In the case of tsunamis, the forces involved are large — and their effects can be correspondingly massive.