Oceanography is the study of the physical, chemical, and biological features of the ocean, including the ocean’s ancient history, its current condition, and its future. In a time when the ocean is threatened by climate change and pollution, coastlines are eroding, and entire species of marine life are at risk of extinction, the role of oceanographers may be more important now than it has ever been.

Indeed, one of the most critical branches of oceanography today is known as biological oceanography. It is the study of the ocean’s plants and animals and their interactions with the marine environment. But oceanography is not just about study and research. It is also about using that information to help leaders make smart choices about policies that affect ocean health. Lessons learned through oceanography affect the ways humans use the sea for transportation, food, energy, water, and much more.

For example, fishermen with the Northwest Atlantic Marine Alliance (NAMA) are working with oceanographers to better understand how pollutants are reducing fish populations and posing health risks to consumers of the fish. Together, NAMA and ocean scientists hope to use their research to show why tighter pollution controls are needed.

Oceanographers from around the world are exploring a range of subjects as wide as the ocean itself. For example, teams of oceanographers are investigating how melting sea ice is changing the feeding and migration patterns of whales that populate the ocean’s coldest regions. National Geographic Explorer Gabrielle Corradino, a North Carolina State University 2017 Global Change Fellow, is also interested in marine ecosystems, though in a much warmer environment. Corradino is studying how the changing ocean is affecting populations of microscopic phytoplankton and the fish that feed off of them. Her field work included five weeks in the Gulf of Mexico filtering seawater to capture phytoplankton and protozoa—the tiniest, but most important, parts of the sea’s food chain.

Of course, oceanography covers more than the living organisms in the sea. A branch of oceanography called geological oceanography focuses on the formation of the seafloor and how it changes over time. Geological oceanographers are starting to use special GPS technology to map the seafloor and other underwater features. This research can provide critical information, such as seismic activity, that could lead to more accurate earthquake and tsunami prediction.

In addition to biological and geological oceanography, there are two other main branches of sea science. One is physical oceanography, the study of the relationships between the seafloor, the coastline, and the atmosphere. The other is chemical oceanography, the study of the chemical composition of seawater and how it is affected by weather, human activities, and other factors.

About 70 percent of Earth’s surface is covered by water. Nearly 97 percent of that water is the saltwater swirling in the world’s ocean. Given the size of the ocean and the rapid advancements in technology, there is seemingly no end to what can and will be uncovered in the science of oceanography.