Oceanography

Oceanography is the study of the biological and physical properties of the world’s largest bodies of water, the oceans.

Oceanography is a branch of Earth science and geography that studies the oceans, including their physical and biological aspects, as well as the interactions between the oceans and the atmosphere, land, and other bodies of water. It involves the study of ocean currents, waves, tides, temperature, salinity, and other physical characteristics, as well as the diverse array of marine life that inhabits the world’s oceans.

Global sea level over the past 540 million years, showing the combined effects of tectonic activity (green), long-term ice changes (red), and both together (dark blue). The light blue shading shows the estimated range of short-term sea level fluctuations caused by changes in Earth’s orbit.

Mapping Short-term Sea Level Changes Over 540 Million Years

Caitlin Dempsey

Study maps 540 million years of sea level change, showing major short-term shifts during ice ages driven by Earth's orbital cycles.

A photo of a wave spray against a cliff by the ocean.

Study Models How the Behavior of Waves Affects Blue Carbon Storage

Caitlin Dempsey

Bubbles created by the movement of waves can influence how much carbon dioxide is absorbed by the ocean.

Colorful tropical fish swim underwater around a reef.

Mapping Coral Reef Health with Sound

Mark Altaweel

Scientists used artificial intelligence and passive acoustic monitoring to assess coral reef health by analyzing the sounds of the ocean.

A polynya that has formed in an embayment where the Venable Ice Shelf meets Farwell Island in Antartica. Photo: John Sonntag/NASA, public domain.

Polynyas: Natural Openings in Polar Ice

Caitlin Dempsey

Explore the geography of polynyas, unique open water areas in polar ice, and learn about their formation, ecological impact, and role in climate dynamics.

A natural shaded relief map of Antarctica showing in a bold line the 60° S extent of the Southern Ocean.

Geography Facts About the Southern Ocean

Caitlin Dempsey

The Southern Ocean is the Earth's windiest, southernmost ocean and plays a vital role in Earth's environmental health.

A couple of small white boats on a hazy day out in the ocean with the coastline in the background.

Marine Spatial Planning Index

Mark Altaweel

The goal of marine spatial planning (MSP) is to balance ocean space use and environmental protection.

A diagram showing the formation of internal waves underneath the surface of the water.

The Role of Internal Waves in Climate Change

Mark Altaweel

Scientists from the UK and US have identified underwater internal waves as crucial in understanding and addressing climate change.

Warming ocean waters stress corals and cause coral bleaching. Colonies of “blade fire coral” that have lost their symbiotic algae, or “bleached,” on a reef off of Islamorada, Florida. Photo: Kelsey Roberts, USGS. Public domain.

Warmer Ocean Temperatures are Bleaching Coral Reefs

Mark Altaweel

Higher ocean temperatures, along with overfishing and pollution, are leading to more coral bleaching events.

A satellite image of Vancouver island showing puffy clouds and swirling green phytoplankton blooms.

Phytoplankton Blooms in the Northeast Pacific Ocean

Caitlin Dempsey

During summer in the Northeast Pacific Ocean, phytoplankton blooms proliferate due to the nutrient-rich upwelling along the continental shelf.

A map of the world showing the global ocean current with warmer waters in red and cold currents in blue.

Potential Collapse of the Atlantic Meridional Overturning Circulation

Mark Altaweel

A new study predicts that the Atlantic meridional overturning circulation (AMOC) could potentially collapse within this century.

A gray shaded relief map with a rainbow categorization showing the densities of sargassum in the Atlantic Ocean.

Sargassum in the Atlantic Ocean Reaches a New Spring High

Caitlin Dempsey

Researchers using remote sensing data from NASA's Aqua and Terra satellites have measured the largest ever March density in the Great Sargassum Belt.

Map showing the Indian Ocean, Oman Sea, and the Red Sea. Map: Epmistes, MediaWiki Commons.

What is the Difference Between a Sea and an Ocean?

Caitlin Dempsey

A look at the geographic definitions of oceans and seas.

A girl with a white sweatshirt and black leggings dances in the shallow water of the beach by the ocean. Her back is to the camera and the sun is shining with a clear blue sky.

Oceans Produce Half of the World’s Oxygen

Caitlin Dempsey

The oceans produce over half of the oxygen in the Earth's atmosphere, making them a vital source of oxygen for life on our planet.

A simple map of the world showing the continents in gray and oceans in blue.

Geography Facts About the Atlantic Ocean

Caitlin Dempsey

The Atlantic Ocean, named after the Greek god Atlas, is the second-largest ocean in the world.

The current US Exclusive Economic Zone is delineated by yellow outlines. As of January 2021, 53 percent of the United States' ocean, coastal, and Great Lakes waterways were unmapped. Map: NOAA Integrated Ocean and Coastal Mapping.

53% of U.S. Ocean, Coastal, and Great Lakes Waters are Unmapped

Caitlin Dempsey

According to a new report by the United States' federal Interagency Working Group on Ocean Coastal Mapping, 53 percent of the country's ocean, coastal, and Great Lakes water is still unmapped.

Map showing the world's ocean gyres. Source: NOAA.

How Ocean Currents Move Pollution Around the World

Katarina Samurović

How does pollution from plastic, trash, and oil spills move around Earth's oceans?

A father and daughter look out at the Pacific Ocean.

How Much Would the Ocean Rise if Everyone Sat in it?

Geo Contributor

If everyone in the world decided to sit in the ocean all at once, how much would the sea level rise?

The Atlantic Ocean in Acadia, Maine. Photo: NPS Photo/Kristi Rugg.

How Many Oceans are There in the World?

Caitlin Dempsey

The world is made up of: one global ocean, three major oceans, four historic oceans, and five world oceans.

Map showing the location of New Guinea. Map: Equal Earth Physical Map, public domain.

What is the Largest Island in the Pacific Ocean?

Caitlin Dempsey

New Guinea is the largest island in the Pacific Ocean.

Drift ice in the Sea of Okhotsk. Image: Landsat 8, NASA.

Lowest Latitude Sea Ice South of the Arctic

Caitlin Dempsey

One of the lowest latitudes in the Northern Hemisphere where sea ice forms in the Northern Hemisphere is the Sea of Okhotsk.

Map of ocean heat content in the upper ocean (from the sea surface to a depth of 700 meters, or 2,300 feet) for 2017 relative to the 1993–2017 baseline. Source: NASA.

Oceans Are Warming 40 Percent Faster Than Previously Estimated

Katarina Samurović

A review of available studies, published in Science in January 2019, has revealed that the rate of ocean warming is as much as 40% faster than that suggested by IPCC.

Geography Facts About the Pacific Ocean

Caitlin Dempsey

Learn some geography facts about the world's largest ocean.

This satellite image shows a phytoplankton bloom stretching along the Malvinas Current for hundreds of miles. Image: MODIS, NASA, 28-December-2017.

Malvinas Current

Caitlin Dempsey

The Malvinas Current is a cold water current that flows northward along Patagonia's Atlantic coast.

How Much Carbon Dioxide are the Oceans Absorbing?

Elizabeth Borneman

New research shows that the world's oceans, which cover 70% of the planet, absorb more carbon dioxide than previously thought.

Gulf of Mexico Remains the Second-largest Low-Oxygen Dead Zone on Earth

Caitlin Dempsey

A newly released forecast by the National Oceanic and Atmospheric Administration (NOAA) has predicted that the Gulf of Mexico will again become the second-largest low-oxygen dead zone on after (after the Baltic Sea).  

Various types and sizes of plastics collected from the Kinnickinnic River, Milwaukee, WI. Photo: S. Mason, State University of New York at Fredonia. Public domain. Source: USGS.

Stokes Drift Is Pushing Microplastics Towards the Arctic

Caitlin Dempsey

A recent publication in JGR Oceans took a look at how the physical processes of oceans affect the distribution of micro plastics around the world.

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