Aquatic ecosystems - Estuaries

ESTUARY

Places where fresh water streams or rivers connect with salt water from the sea or oceans is called an estuary. Mixing of freshwater from rivers and salt water in oceans creates a unique ecosystem

• Estuaries contain high amount of nutrients
• Microflora (algae) and macroflora (seaweeds,marshgrass and mangrove trees) are found in estuaries
• Estuaries support diverse fauna like oysters, crabs and waterfowl
• Net Primary Productivity of estuaries is very high (200 - 300 g/m2)
• High productivity of estuaries is because of the large amounts of nutrients that enter the basin from rivers flowing into it

Characteristics of estuaries:

• Water is moderately salty in this region
• Estuaries contain rich sediments that are carried by river water and form SHOALS and MUD FLATS that nurture a multitude of aquatic life
• Estuaries are not affected by ocean action. They experience tidal waves and flows which cause rise and fall in river water level at some distance from the river mouth
• The productivity of estuarine ecosystem is high
• Species diversity is high
• Delta regions are biologically rich because of steady flow of nutrients into estuaries  ESTUARINE ECOSYSTEM
• Estuaries are transition zones that are strongly affected by tides of the sea.
• Water characteristics change periodically
• Living organisms in estuarine ecosystems have wide tolerance.
• Salinity in estuarine water is high during summer and lest during winter
  

An estuary is a partially enclosed coastal area at the mouth of a river where sea water mixes  with fresh water. It is strongly affected by tidal action. Estuaries are usually nutrients in abundance. Estuaries are useful to human beings due to their high food potential. Hence, estuaries must be protected from pollution.

STRUCTURE AND FUNCTION

Abiotic components
Temperature, pH, sodium and potassium salts and various nutrients.
Biotic components

1. Producers: Ex - Marsh grass, sea-weeds, sea-grass and phytoplankton
2. Consumers: Ex - Oysters, Crabs, Seabirds and small fish
3. Decomposers: Ex - Bacteria, Fungi  and actinomycetes