SALTWATER 
SALTWATER 
SALTWATER 
FRESHWATER 
FRESHWATER 
FRESHWATER 
FRESHWATER
There are two types of aquatic ecosystems: 
•Freshwater or inland ecosystems. 
•Saltwater or marine ecosystems.
Inland or freshwater ecosystems have important 
factors such as: light, dissolved gases and 
temperature.
freshwater ecosystems
freshwater ecosystems 
Ecosystems of static water. They can be very 
small like Cuicocha in Ecuador, or very big like 
the Titicaca in Bolivia. Water plants and algae 
grow on the surface.
freshwater ecosystems
freshwater ecosystems 
They begin in the mountains and contain a lot of 
oxygen. Plants grow on the rocks and fish are 
abundant.
freshwater ecosystems
freshwater ecosystems 
They are frequently flooded by fresh or 
seawater. Lots of insects, birds and reptiles live 
there.
Marine ecosystems provide human beings with great 
quantities of food and other resources. Abiotic factors 
that regulate these ecosystems are: light, dissolved salt, 
temperature and ocean currents. These ecosystems are:
Marine ecosystems
Marine ecosystems 
Large algae and microscopic plants produce the greatest 
amount of oxygen on the planet by photosynthesis. It is 
the home of invertebrates like jellyfish, anemones, 
starfish, coral and octopuses (octopi), and vertebrates 
like fish and marine mammals.
Marine ecosystems
Marine ecosystems
Marine ecosystems
Marine ecosystems 
Microscopic plants 
(Phytoplankton)
Marine ecosystems
Marine ecosystems
Marine ecosystems
Marine ecosystems
Marine ecosystems
Marine ecosystems 
Salinity in this ecosystem is less than that of the 
ocean.
Marine ecosystems
Marine ecosystems 
An estuary is a partially enclosed body of water along the coast 
where freshwater from rivers and streams meets and mixes with 
salt water from the ocean. 
A very large biological productivity and 
biodiversity is found in this ecosystem.
Marine ecosystems
Marine ecosystems 
They are formations produced from the remains 
of living things in tropical water that gather in 
colonies of corals. There are fish, crabs, starfish, 
urchins and others.
An ecosystem should have living things that 
interact among themselves and with the non-living 
factors such as the sunlight, water, air and 
soil. 
MARINE ECOSYSTEM INLAND ECOSYSTEM
Do you think that a swimming pool is an 
ecosystem?
Block 3   Water in the Ecosystems

Block 3 Water in the Ecosystems