Journal of Ecology and Conservation

Marine Ecosystems

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Marine ecosystems include oceans, seas, and coastlines, on which a wide range of life forms exist. Marine ecosystems play key services, including climate regulation, support for fisheries, and biodiversity maintenance. Marine ecosystems are threatened by overfishing, pollution, and climate change. Conservation of marine ecosystems entails sustainable fishing, plastic pollution reduction, and setting up marine protected areas to preserve species and habitats. Healthy marine ecosystems are essential to sustaining global ecological balance and supporting human livelihoods.

Over 70% of the Earth's surface is made up of marine waters, which also provide more than 97% of the planet's water supply and 90% of its livable space. The average salinity of seawater is 35 parts per thousand of water. Different marine environments have varying actual salinities.

Depending on coastline features and water depth, marine habitats can be classified into a variety of zones. The large open area of the ocean where creatures like whales, sharks, and tuna reside is known as the oceanic zone. Substrates below water make up the benthic zone, which is home to a variety of invertebrates.

The physical environment and the biological population of creatures with which they are related define marine ecosystems. Sharks, cephalopods, echinoderms, corals, brown algae, and dinoflagellates are among the groups of organisms that inhabit marine environments.

For large segments of the world's population, marine habitats provide vital ecological services, food, and employment. The stability of marine ecosystems is seriously threatened by pollution and human activities of these environments. Unsustainable use of marine resources is one of the environmental issues affecting marine ecosystems.

Marine coastal ecosystems

Coral reefs

Coral reefs are one of the most well-known marine ecosystems in the world, with the largest being the Great Barrier Reef. These reefs are composed of large coral colonies of a variety of species living together. The corals form multiple symbiotic relationships with the organisms around them.

Mangroves

In tropical or subtropical latitudes, mangroves are plants or bushes that thrive in low-oxygen soil close to coasts.  These ecosystems, which link the land and the water, are incredibly complex and productive.  The species that make up mangroves are not always related to one another; instead, they are frequently classified together based on shared traits rather than genetic resemblance.  All of them have evolved adaptations to survive in salty, oxygen-depleted water due to their closeness to the coast, including salt excretion and root aeration.

Seagrass meadows

Seagrasses provide one of the world's most prolific ecosystems: thick underwater meadows. Like coral reefs, they offer food and habitat to a variety of aquatic creatures. This includes birds, marine mammals, and invertebrates such as shrimp, crabs, cod, and flatfish. They provide as havens for threatened species like dugongs, seahorses, and turtles.

It also includes Kelp forests, Estuaries, Lagoons, Salt marsh, Intertidal zones.

Ocean surface ecosystem

Keystone creatures like the golden seaweed Sargassum, which forms the Sargasso Sea, floating barnacles, marine snails, nudibranchs, and cnidarians are examples of animals known as neustons that live freely at the surface. Numerous fish species that are significant to the environment and the economy either dwell in or depend on neuston. The distribution of species at the ocean's surface is not uniform; distinct neustonic categories and ecoregions are found exclusively in particular ocean basins and at specific latitudes.