Marine Science and Ecosystems Archives | Oceana

Seagrass Bed

Seagrasses are not true grasses but are flowering plants that carry out their entire lifecycles underwater. Like all plants, seagrasses rely on sunlight to convert carbon dioxide into food/energy (via a process called photosynthesis). Therefore, they only succeed in clear, shallow waters. When the conditions are just right, seagrasses can densely cover the sea floor, … Read more

Rocky Shore

Rocky shores, like beaches (or sandy shores) are characterized by the life that lives in the intertidal zone – the area between the high tide and low tide water levels. Life on rocky shores is tough. It is dominated by the need to deal with very high wave energy, regular exposure to the air/sun, and … Read more

Open Ocean

Many species that live in the open ocean (or pelagic realm) truly live in an ocean universe. More than 70% of the Earth’s surface is covered by ocean, and it is important to remember that more than 50% of the Earth’s surface is covered by ocean that is at least two miles (3.2 km) deep. … Read more

Mangrove Forest

Mangroves are trees that live along tropical coastlines, rooted in salty sediments, often underwater. Like seagrasses, mangroves are flowering plants, but unlike seagrasses, most of the plant lives above water. The upper trunk and all of the branches and leaves of a mangrove tree live completely above the water line, while the lower trunk and … Read more

Kelp Forest

Kelp forests are underwater ecosystems formed in shallow water by the dense growth of several different species known as kelp. Though they look very much like plants, kelps are actually extremely large brown algae. Some species can reach heights (underwater) of 150 feet (45 m), and under ideal physical conditions, kelp can grow 18 inches … Read more

Ice Edge

Sea ice at both the North and South Poles forms a variety of dynamic ecosystems that change with the season. Several iconic species rely on sea ice formation and movement for some or all of their life history stages. As the poles continue to warm, in the face of ongoing climate change, sea ice ecosystems … Read more


Fjords are long, narrow, deep bodies of water along the coasts of formerly glaciated areas. As glaciers historically flowed to the coast, they eroded deep, sharp canyons. Fjords were created once the glaciers melted and the canyons were flooded by rising sea levels. These marine ecosystems are typically surrounded by tall mountains with steep sides … Read more

Deep Hydrothermal Vent

Deep hydrothermal vents are like hot springs on the sea floor where mineral-rich, hot water flows into the otherwise cold, deep sea. Complete ecosystems sprout up around these vents, and numerous organisms are supported by the energy given off at these rare sites. Deep hydrothermal vents are located in areas with high tectonic activity, including … Read more

Coral Reef

Often nicknamed the “rainforests of the sea,” coral reefs are some of the most diverse ecosystems on Earth. Scientists believe that more than a million species around the world live on coral reefs. At any one reef, thousands of species can be collected or observed living there. It is therefore not surprising that coral reef … Read more


Most people are very familiar with beaches. Beaches are fun places where people enjoy the intersection of very different terrestrial and marine environments, and millions of tourists visit beaches every year. Even people who have never visited a beach have likely seen a photograph or video of one, making beaches one of the most recognizable … Read more