Types of Ecosystems
{AQUATIC ECOSYSTEM}
 What is an Aquatic Ecosystem?
Ecosystem that exists in water bodies and includes interaction between living (biotic) and non living
(abiotic)components.
Includes plants, animals, and microorganisms living in water(support diverse life).
Organisms interact with water, sunlight, and nutrients.
Cover about 71%of Earth’s surface.
Biotic Components
Abiotic Components
• Producers(Algae , Phytoplankton)
• Consumers(Fish, Zooplankton)
• Decomposers(Bacteria, Fungi)
• Light , Temperature, Dissolved
oxygen , Salinity , Nutrients
Aquatic Ecosystem(on the basis of salinity,
depth, water flow)
Freshwater
ecosystem
Lentic
Lotic
Marine
Ecosystem
Wetlands
Coastal
(Brackish
water)
Coral reefs,
Oceans
(Saline water)
Estuarine
Ecosystem
(transitional)
Estuaries
 Types of Freshwater Ecosystem And Types/Zones of Marine
Ecosystem
Freshwater
Ecosystem
Lentic
Ecosystem(Still
water)
Lotic
Ecosystem(Flowing
water)
Water flows
continuously
Water does not flow
Has dissolved
oxygen
Has zones (littoral,
limnetic, profundal)
• MARINE ECOSYSTEM ZONE
Rich biodiversity {ponds
,lakes)
• Intertidal zone → area between high and low
tide
• Neritic zone → shallow coastal waters (rich in
life).
• Oceanic zone → deep sea (less light, fewer
organisms)
• Benthic zone → sea floor
Examples {rivers,
streams}
Feature
Freshwater Ecosystem
Marine Ecosystem
Definition
Low salt water (<1%)
High salt water (~3.5%)
Location
Inland
Oceans and seas
Types
Lentic , Lotic
Intertidal ,Neritic etc.
Light
Reaches bottom
Decreases with depth
Biodiversity
Moderate
High
Examples
Rivers , Lakes
Oceans , Coral reefs
 FRESHWATER ECOSYSTEM (PONDS)
• Pond ecosystem is a freshwater aquatic ecosystem.
• It is small, shallow (sunlight reaches bottom) , and still water
body.
• Supports a variety of plants, animals, and microorganisms.
• Easy to study due to its simple structure.
• Seasonal changes visible.
• Food Chain in Pond
Phytoplankton → Zooplankton → Small fish → Large fish → Birds {Shows
energy flow in ecosystem}
• Nutrients circulate between biotic and abiotic components
• Decomposers break down dead matter and release nutrients.
• Nutrients reused by plants.
• Importance of Pond Ecosystem includes supports biodiversity,
Provides water for animals, helps in groundwater recharge ,
Maintains ecological balance, Important for environment and
biodiversity and is a self-sustaining system
 FRESHWATER ECOSYSTEM(LAKES)
• A lake ecosystem is a large freshwater aquatic ecosystem
with standing (still) water divided into zones.
• Usually deeper than ponds and shows clear stratification
(layering).
 Thermal stratification:
Formation of layers : Epilimnion{Warm upper layer}
Thermocline{Temperature transition layer}, Hypolimnion{Cold
bottom layer})based on temperature.
 Oxygen Stratification: High oxygen at surface, low at deeper
•Littoral Zone: Shallow, near shore, rich in plants
levels.
•Limnetic Zone: Open surface water, sunlight present
 Productivity Types: Can be oligotrophic(Low nutrients,
•Profundal Zone: Deep, dark region, low light
clear water), mesotrophic(Moderate nutrients), or
•Benthic Zone: Bottom, rich in decomposers(Organic
eutrophic(High nutrients, high productivity).
matter settles at bottom )
 Examples of Lakes : Dal lake, Sambhar lake, Naini lake etc.
 FRESHWATER ECOSYSTEM(STREAMS AND RIVERS)
RIVER ECOSYSTEM
•Flowing freshwater ecosystem (lotic system)
•Continuous water movement from higher to lower
altitude.
•High oxygen content due to constant mixing.
•Low nutrient retention (nutrients carried away by
flow).
•No clear stratification like lakes.
•Organisms show adaptations to current
(streamlined body, attachment)
•Temperature varies with season and altitude
•Substrate includes rocks, gravel, sand.
• Animals in Streams includes fish like Trout, salmon
(strong swimmers);Insects like Mayfly larvae, stonefly,
caddisfly; Amphibians: Frogs, salamanders and Birds
like Kingfishers.
•Flowing freshwater ecosystem (lotic system)
•Water flows from source (mountains) to mouth
(sea/ocean)
•Divided into upper, middle, and lower course
•High dissolved oxygen in upper course, decreases
downstream
•Nutrient content increases downstream
•No stratification like lakes
•Organisms show adaptation to current (streamlined
bodies, strong swimming)
•Substrate varies: rocks (upper) → sand/silt (lower)
 FRESHWATER ECOSYSTEM (RIVERS)
1. Source:
The origin of the river, usually from mountains, glaciers, or springs.
2. Tributary:
Smaller streams that join the main river.
3. Confluence:
The point where two or more rivers meet.
4. River Channel:
The path/route through which river water flows.
5. Meander:
Curves or bends formed due to erosion and deposition.
6. Oxbow Lake:
A U-shaped lake formed when a meander is cut off.
7. Levee:
Natural raised banks formed by sediment deposition along river sides.
8. Estuary:
Area where river meets the sea,( mix of fresh and saltwater).
9. Delta:
Triangular landform formed by deposition of sediments at river
mouth.
10. Mouth:
The place where river ends and enters sea/ocean.
 MARINE ECOSYSTEM(OCEANS)
Largest
Includes
aquatic
oceans,
ecosystem
seas, coral
covering
reefs,
~70% of
estuaries.
Earth’s
surface
Water is salty
Light
(high salinity).
decreases with
High biodiversity,
depth →
especially in coral
affects
reefs
photosynthesis
Shows
zonation:
Intertidal,
Neritic,
Oceanic
zones
Regulates
climate &
oxygen
production
Animals:
Fish,
dolphins,
whales,
octopus,
crabs,
starfish.
•Carbon Sink
•Oceans absorb large amounts of
carbon dioxide (CO₂)
•Helps reduce global warming
•Adaptations of Organisms
•Streamlined bodies for swimming,
•Bioluminescence in deep sea animals,
•Salt regulation mechanisms.
Examples of Oceans / Marine
Ecosystem:
Pacific Ocean
Atlantic Ocean, Bay of Bengal
The ocean have two major life zones:
1. Coastal zone or neritic zone:
it is relatively warm, nutrient rich shallow water.
2. Open sea:
Deeper part of the ocean, away from the continental
shelf. It is vertically divided into three regions:
i. Euphotic zone: receive abundant light and shows
high photosynthetic activity
ii. Bathyal zone: receive dim light and is usually
geologically active
iii. Abyssal zone: is a dark zone and It has no primary
source of energy i.e. solar energy.
 MARINE ECOSYSTEM (ESTUARIES)
•Animals:
•Fish, crabs, prawns, oysters, migratory
birds
•Importance:
•Supports high biodiversity.
•Protects coast from erosion.
•Important for fisheries.
•Examples:
• Area where river meets the sea
• Mixture of freshwater and saltwater (brackish
water)
• Highly nutrient-rich and productive ecosystem.
Feature
• Water salinity varies with tides.
Definition
• Characteristics:
• Influenced by tides (high & low tide)
• Sediment deposition is common
Water type
•Coastal bays (Can be estuaries if freshwater from
rivers mixes with seawater) ,
•Tidal marshes
Bay
Estuary
Part of sea enclosed by land
Salty
River mouth where it meets
the sea
Brackish
River
presence
Not required
Always present
Formation
Coastal land shape
River and tidal action
Productivity
Moderate
Very high
Example
Bay of Bengal
Sundarbans Estuary
 BIBLIOGRAPHY