Aquatic ecosystems

Aquatic Ecosystems

Marine eco systemsOpen sea

CoastalEstuary and salt marshes

Coral reefs and mangroves

An ecosystem located in water bodies

Open sea

Estuary and salt marshes

Coral reefs and mangroves

rivers, streams and springs

ponds

lakes

Fresh water ecosystems

Flowing water (rivers, streams and springs)

Static / slow moving water (ponds, lakes, pools / swamps)

Fresh Water Ecosystems

• Fresh water covers 0.8% of the Earth's surface and contain 0.009% of its total water.

• Freshwater ecosystems contain 41% of the world's known fish species.

• Two types of freshwater ecosystems:– Lotic : Flowing water (rivers, streams and springs)– Lentic: Static / slow moving water (ponds, lakes, pools)

Lotic EcosystemsSpecies adapted to live in conditions of constant flow

Variation in lotic ecosystems (even within a river or a stream) is considerable and is determined by Shape of stream / river bed (can form microhabitats) Stream / river bed's gradient Quantity of water Velocity of the current

Faster moving water has higher concentrations of dissolved oxygen, and therefore supports greater biodiversity

Light Temperature

most lotic species are poikilotherms, whose internal temperature varies with the surrounding temperature

Water chemistry (which changes in large rivers)

Lotic Ecosystems

riparianSunlightnutrients

decomposersPrimary producers

Macroinvertebrates

FishFrog

amphibians

reptiles

Mammals (dolphins, otters)

Reptiles (turtles, crocodiles, snakes)

Amphibians (salamander)

Fish

Macro invertebratesInsectsMolluscs (snails, clams, mussels) Crustaceans (crabs)

Bacteria

Primary producers Algae, Mosses, Liverwort,

Duckweed, Water hyacinth

Lentic EcosystemsLakes are heterogenous and not a uniform mass of water

Biodiversity within a lake is also variable and depends on

Physical characteristics LightTemperatureWater currents

Chemical characteristicsNutrientsContaminants

Lake zones

Terrestrial plantsLittoral zone

Emerged plants

Floating plants

Limnetic zone (open water)

Submerged plants

Euphotic zone

Benthic zone

Lake organismsCreatures that go where ever they choose to go

Creatures that go where ever the water takes them

Creatures that live on the lake bottom

fish

amphibians

Larger zooplanktons

Living creatures – planktonsAnimals: zooplanktons Algae : phytoplanktonBacteria : bacterioplankton

Dead creatures –DetritiusInternal: produced within lakeExternal: washed in from wash shed

AnimalsAquatic insects, clams, snailsworms, cray fish

Plantsmacrophytesperiphyton

Bacteria and fungiSewage sludge

NUTRIENTS

EAT

USE

RECYCLE

EAT

EAT

PISCIVOROUSFISH

PLANKTIVOROUSFISH

ZOOPLANKTON

ALGAE

BENTHIC ORGANISMS

The food chain in a lake

Food and energy web in a lake

DECOMPOSERS

LOSSTHROUGH

OUTLET

LOST TO SEDIMENTS

RECYCLED NUTRIENTS TERITIARY CONSUMERS

SECONDARY CONSUMERS

PRIMARY CONSUMERS

PRIMARY PRODUCERS

OUTSIDE NUTRIENTSSOLAR ENERGY

RECYCLED NUTRIENTS

Ocean zones

6,000m

10,000m

2000 to 1,000m

200m

700 to 1,000m

4 degree C

10 degree C

Marine ecosystems

Spread over 71% of the Earth’s surface

Open sea

Coastal

Estuary and salt marshes

Coral reefs and mangroves

Each is a complex ecosystem

Producers, consumers and decomposers as

in other ecosystems

http://www.earthhistory.org.uk/

http://www.nu.ac.za

http://www.learnnc.org/

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