1. N A M E – S A M A D R I T A B A N I K
S T . G E O R G E C O L L E G E
M . S C M I C R O B I O L O G Y
2 N D S E M
FRESH AND MARINE
ECOSYSTEM
2. INTRODUCTION
Freshwater ecosystems are a subset of Earth's aquatic
ecosystems. They include lakes and ponds, rivers,
streams, springs, bogs, and wetlands. They can be
contrasted with marine ecosystems, which have a
larger salt content.
3. FRESH WATER AND MARINE ECOSYSTEM
Freshwater and marine ecosystems cover more than
three-quarters of the Earth’s surface, providing an
array of critical ecosystem services, from participating
in various biogeochemical cycles and nutrient
exchange, to providing natural protection and habitat,
to degrading and dispersing many environmental
pollutants.
4. 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.
5. TYPES OF MARINE ECOSYSTEM
Salt marsh
Salt marshes are a transition from the ocean to the
land, where fresh and salt water mix.The soil in these
marshes is often made up of mud and a layer of
organic material called peat. Peat is characterized as
waterlogged and root-filled decomposing plant matter
that often causes low oxygen levels.
6. Mangrove
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 together
for the characteristics they share rather than genetic
similarity.
7. Intertidal zone
Intertidal zones are the areas that are visible and
exposed to air during low tide and covered up by
saltwater during high tide.There are four physical
divisions of the intertidal zone with each one having
its own distinct characteristics and wildlife. These
divisions are the Spray zone, High intertidal zone,
Middle Intertidal zone and Low intertidal zone.
8. Estuaries
Estuaries occur where there is a noticeable change in
salinity between saltwater and freshwater sources.
This is typically found where rivers meet the ocean or
sea. The wildlife found within estuaries is quite
unique as the water in these areas is brackish - a mix
of freshwater flowing to the ocean and salty
seawater.
9. Lagoons are areas that are separated from larger water
by natural barriers such as coral reefs or sandbars.
There are two types of lagoons, coastal and
oceanic/atoll lagoons.
Lagoons
10. Coral reef
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.
11. Deep sea community
The deep sea contains up to 95% of the space
occupied by living organisms. Combined with the sea
floor , these two areas have yet to be fully explored
and have their organisms documented.
12. THREATS
Human exploitation and development
Coastal marine ecosystems experience growing
population pressures with nearly 40% of people in the
world living within 100 km of the coast.Humans often
aggregate near coastal habitats to take advantage of
ecosystem services.
16. CONCLUSION
Marine ecosystems are an important part of the world,
because the marine ecosystems give marine life such
as: tiny plankton, fish, crustaceans, invertebrates,
reptiles, marine mammals, sharks, and rays a place to
live and survive. It also gives those marine animals a
place to hunt. Many marine life have an important role
in the world such as the tiny plankton because without
them the world would build up with carbon dioxide,
the plankton absorbs the carbon dioxide in the air and
releases oxygen back into the air.
