"Corallines, corals, goldies, reef and surface at Halahi Reef, Red
Sea"
by
Derek Keats
is licensed under
CC BY 2.0
Marine ecosystems are the largest of Earth's aquatic ecosystems and
exist in waters that have a high salt content. These systems contrast
with freshwater ecosystems, which have a lower salt content. Marine
waters cover more than 70% of the surface of the Earth and account for
more than 97% of Earth's water supply and 90% of habitable space on
Earth. Seawater has an average salinity of 35 parts per thousand of
water. Actual salinity varies among different marine ecosystems.
Marine ecosystems can be divided into many zones depending upon water
depth and shoreline features. The oceanic zone is the vast open part
of the ocean where animals such as whales, sharks, and tuna live. The
benthic zone consists of substrates below water where many
invertebrates live. The intertidal zone is the area between high and
low tides. Other near-shore (neritic) zones can include mudflats,
seagrass meadows, mangroves, rocky intertidal systems, salt marshes,
coral reefs, lagoons. In the deep water, hydrothermal vents may occur
where chemosynthetic sulfur bacteria form the base of the food web.
Marine ecosystems are characterized by the biological community of
organisms that they are associated with and their physical
environment. Classes of organisms found in marine ecosystems include
brown algae, dinoflagellates, corals, cephalopods, echinoderms, and
sharks (Wikipedia).
Coral Reefs
Ritiks, CC BY-SA 3.0
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 from multiple symbiotic relationships with the organisms around them.
Mangroves
Anagounagi, CC BY-SA 4.0
Mangroves are trees or shrubs that grow in low-oxygen soil near coastlines in tropical or subtropical latitudes.They are an extremely productive and complex ecosystem that connects the land and sea. Mangroves consist of species that are not necessarily related to each other and are often grouped for the characteristics they share rather than genetic similarity.[10] Because of their proximity to the coast, they have all developed adaptions such as salt excretion and root aeration to live in salty, oxygen-depleted water. Mangroves can often be recognized by their dense tangle of roots that act to protect the coast by reducing erosion from storm surges, currents, wave, and tides. The mangrove ecosystem is also an important source of food for many species as well as excellent at sequestering carbon dioxide from the atmosphere with global mangrove carbon storage is estimated at 34 million metric tons per year.