Difference between ecosystems

Fresh water, Brackish water, and Salt water

Fresh Water

  • Generally almost devoid of salt
  • less than .05% salinity
  • Density of 1 g/ml
  • It makes up less than 1% of the worlds water
  • Animals that live here would not be able to survive in water that is salty
  • Lakes, ponds, rivers, streams, wetlands


Examples of organisms that live here:

Brackish Water

  • Mixture of salt and freshwater
  • A salinity of about .05% - .3%
  • Usually happens when rivers meet the sea or lakes are fed by saltwater estuaries
  • Can be dangerous to the environment because they can kill native species
  • Certain lakes, estuaries, and mangroves


Organisms that live there are specially adapted to the salinity of the water:



Salt Water

  • On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, or 599 mM). This means that every kilogram (roughly one litre by volume) of seawater has approximately 35 grams (1.2 oz) of dissolved salts.
  • Salt water has an average density of 1.025 g/ml, but the density increases as you go deeper.
  • Salt water is unsuitable for human consumption
  • Salt water in the oceans is home to millions of species of life.
  • Salt water is denser than fresh water
  • Seas, and Oceans


Here are just some of the animals and plants that live there: