2. Marine Ecosystem
◦ Marine ecosystems are the largest of Earth's aquatic ecosystems and are distinguished by 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. Marine ecosystems include
nearshore systems, such as the salt marshes, mudflats, seagrass meadows, mangroves, rocky
intertidal systems and coral reefs. They also extend outwards from the coast to include offshore
systems, such as the surface ocean, pelagic ocean waters, the deep sea, oceanic hydrothermal vents,
and the sea floor. Marine ecosystems are characterized by the biological community of organisms
that they are associated with and their physical environment.Marine ecosystems are important
sources of ecosystem services and food and jobs for significant portions of the global population.
Human uses of marine ecosystems and pollution in marine ecosystems are significantly threats to
the stability of these ecosystems. Moreover, much of the carbon dioxide causing global warming and
heat captured by global warming are absorbed by the ocean, ocean chemistry is changing through
processes like ocean acidification which in turn threatens marine ecosystems. Because of these
opportunities in marine ecosystems for humans and the threats created by humans, the international
community has prioritized "Life below water" as Sustainable Development Goal 14 to "Conserve and
sustainably use the oceans, seas and marine resources for sustainable development".
3. Marine animals
Whales
Whales are a widely distributed and diverse group of fully aquatic placental marine
mammals. They are an informal grouping within the infraorder Cetacea, usually
excluding dolphins and porpoises. Whales, dolphins and porpoises belong to the order
Cetartiodactyla, which consists of even-toed ungulates.
4. Marine Animals
◦Dolphins
◦ Dolphin is a common name of aquatic mammals within the infraorder Cetacea. The
term dolphin usually refers to the extant families Delphinidae, Platanistidae, Iniidae,
and Pontoporiidae, and the extinct Lipotidae. There are 40 extant species named as
dolphins.
5. Marine animals
◦Sea Lions
◦ Sea lions are pinnipeds characterized by external ear flaps, long foreflippers, the ability to walk
on all fours, short, thick hair, and a big chest and belly. Together with the fur seals, they
comprise the family Otariidae, eared seals, which contains six extant and one extinct species in
five genera.
6. Marine Animals
◦ Octopus
◦ Octopus relates to approximately 300 species of soft-bodied, eight-
limbed molluscs of the order Octopoda. The order is grouped within the
class Cephalopoda with squids, cuttlefish, and nautiloids. An octopus
blood color is blue and he have three hearts and nine brains.
7. Marine animals
◦ Starfish
◦ Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea.
Common usage frequently finds these names being also applied to ophiuroids, which
are correctly referred to as brittle stars or basket stars. Starfish are also known as
Asteroids due to being in the class Asteroidea.
This Photo by Unknown Author is licensed under CC BY-SA
8. Corals
◦A coral reef is an underwater ecosystem
characterized by reef-building corals. Reefs are
formed of colonies of coral polyps held together by
calcium carbonate. Most coral reefs are built from
stony corals, whose polyps cluster in groups.
9. SeaGrasses
◦ Seagrasses have been called “the lungs of the sea” because they release oxygen into the water
through the process of photosynthesis. There are 26 species of seagrasses in North American
coastal waters. They prefer to grow in shallow, sheltered, soft-bottomed coastal waters—both
tropical and temperate. Seagrasses are the only flowering plants which grow in marine
environments. There are about 60 species of fully marine seagrasses which belong to four
families, all in the order Alismatales. Seagrasses evolved from terrestrial plants which
recolonised the ocean 70 to 100 million years ago.
This Photo by Unknown Author is licensed under CC BY-SA
10. Types of SeaGrasses
◦ Kelps
◦ Kelps are large brown algae seaweeds that make up the order Laminariales. There
are about 30 different genera. Despite its appearance, kelp is not a plant; it is a
heterokont. Kelp grows in "underwater forests" (kelp forests) in shallow oceans, and
is thought to have appeared in the Miocene, 5 to 23 million years ago.
This Photo by Unknown Author is licensed under CC BY-SA-NC
11. Types of SeaGrasses
◦Red Algae
◦ Red algae, or Rhodophyta, are one of the oldest groups of eukaryotic algae. The
Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000
currently recognized species with taxonomic revisions ongoing.
12. Types of SeaGrasses
◦Saragassum
◦ Sargassum is a genus of brown macroalgae in the order Fucales. Numerous species
are distributed throughout the temperate and tropical oceans of the world, where they
generally inhabit shallow water and coral reefs, and the genus is widely known for its
planktonic species.
13. Salt Marsh
◦ Salt marshes are coastal wetlands that are flooded and
drained by salt water brought in by the tides. They are
marshy because the soil may be composed of deep mud and
peat. Peat is made of decomposing plant matter that is often
several feet thick. Peat is waterlogged, root-filled, and very
spongy. A salt marsh or saltmarsh, also known as a coastal
salt marsh or a tidal marsh, is a coastal ecosystem in the
upper coastal intertidal zone between land and open
saltwater or brackish water that is regularly flooded by the
tides.
14. Fisheries and Seafood
◦Seafood plays an essential role in feeding the world’s
growing population. Healthy fish populations lead to
healthy oceans and it’s our responsibility to be a part
of the solution. The resilience of our marine
ecosystem and coastal communities depend on
sustainable fisheries.
15. Marine Food Chain
◦ Level one: Photoautotrophs
◦ The foundation of the sea's food chain is largely invisible.
Countless billions of one-celled organisms, called
phytoplankton, saturate sunlit upper-ocean waters
worldwide. These tiny plants and bacteria capture the sun's
energy and, through photosynthesis, convert nutrients and
carbon dioxide into organic compounds. On the coast,
seaweed and seagrasses do the same thing.
16. Marine Food Chain
◦ Level two: Herbivores
◦ The next level of the marine food chain is made up of animals
that feast on the sea's abundant plant life. On the ocean's
surface waters, microscopic animals—zooplankton, which
include jellyfish and the larval stages of some fish, barnacles,
and mollusks—drift across the sea, grazing opportunistically.
Larger herbivores include surgeonfish, parrotfish, green
turtles, and manatees.
17. Marine Food Chain
◦ Level three: Carnivores
◦ The zooplankton of level two sustain a large and diverse group of small
carnivores, such as sardines, herring, and menhaden. This level of the
food chain also includes larger animals, such as octopuses (which feed
on crabs and lobsters) and many fish (which feed on small invertebrates
that live near shore). Though these animals are very successful hunters,
they often fall prey to a simple fact of ocean life: big fish eat smaller fish.
◦
18. Marine Food Chain
◦ Level four: Top Predators
◦ The large predators that sit atop the marine food chain are a
diverse group that includes finned (sharks, tuna, dolphins),
feathered (pelicans, penguins), and flippered (seals,
walruses) animals. These apex predators tend to be large,
fast, and very good at catching prey. They are also long-lived
and usually reproduce slowly.
19. Alternative Food Chain
The primary marine food web, which is based on plant productivity,
includes many of the sea’s species—but not all of them. There are other
deep-ocean ecosystems that are entirely independent of the sunlight
energy that kick-starts the main marine ecosystem. At their roots, these
unique ecosystems are fuelled by chemical energy, which enters the
ocean from sources like seafloor hydrothermal vents.
20. Did You Know?
◦Do you know that the Ice cream we
eat is made out of kelp
