Marine Science and Ecosystems Archives - Oceana

Kelp Forest

Kelp thrives in cold, nutrient-rich waters. Because kelp attaches to the seafloor and eventually grows to the water’s surface and relies on sunlight to generate food and energy, kelp forests are always coastal and require shallow, relatively clear water. Generally speaking, kelps live further from the tropics than coral reefs, mangrove forests, and warm-water seagrass beds, so … Read more

Ice Edge

In order to understand sea ice ecosystems, it is important to understand the ice itself. Not all sea ice is the same. Scientists classify this ice based on its ability to drift and its age. Ice that is attached to the shore or to the seafloor is called ‘fast ice’ because it is ‘fastened.’ Ice that is adrift is … Read more


As a result of these steep sides, fjords can reach extreme depths only a few meters from shore; the deepest fjords are up to 6300 feet (nearly 2000 m) deep. The long, narrow nature of fjords means that they may extend far inland from the coast; the longest fjords extend hundreds of kilometers inland. Most fjords … Read more

Deep Hydrothermal Vent

Deep hydrothermal vents are located in areas with high tectonic activity, including the edges of tectonic plates, undersea mountain ranges and seamounts, and mid-ocean ridges. The water escaping from deep hydrothermal vents may be clear-ish and have low concentrations of minerals or it may be white or black and be characterized by high concentrations of minerals. These … Read more

Coral Reef

Coral reefs are made of the calcium carbonate skeletons of corals – small immobile animals closely related to jellyfish. Though individual corals can be quite small, they live with millions of other individuals, and over the course of hundreds of thousands of years, they build reefs that are absolutely enormous. The largest coral reef in the world, … Read more


Beaches occur in areas where fairly strong wave action deposits sand, and a lack of strong currents prevents it from being carried away. Sand can either be geological or biological in origin. Geological sand is a result of the weathering of rocks. Biological sand comes from the breakdown of coral skeletons, shells, and other hard body parts from … Read more

Seagrass Bed

Several different species of plants, representing at least four distinct families, are collectively known as the seagrasses, so the term does not accurately describe an individual group of plants. The diversity of species involved in forming seagrass beds leads to the wide geographic distribution of this ecosystem; seagrass beds can be found from the tropics nearly … Read more

Rocky Shore

The rocky shore is one of the best-studied marine ecosystems, and many of the earliest discoveries about marine ecology were made by scientists who study the complex marine communities that live in this system. Early on, some of these researchers discovered vertical zonation in rocky shore communities. Species closer to the high tide mark are often the … Read more

Open Ocean

Many open ocean organisms live out their existence without ever coming into contact with the shore, the seafloor, or the water’s surface. They spend their entire lives surrounded by water on all sides and do not know that anything else even exists. In the case of the deep open ocean, organisms never even see sunlight. … Read more

Mangrove Forest

This structure creates an intricate network of habitat for numerous amphibious and marine animals. Mangroves are some of the only coastal plants that can live in saltwater, and when conditions are favorable, they cover the coastline in dense patches known as mangrove forests or swamps. As the primary species involved in forming mangrove forests prefer very warm, … Read more