Different Water Ecosystems

Freshwater - Brackish Water - Saltwater

By Grace Ko

Freshwater Ecosystems

  • Salt content: less than 1 percent or less than 500 ppm (parts per million)
  • Types or examples of freshwater ecosystems are ponds, rivers, lakes, streams, and wetlands
  • Ponds are often seasonal, where as lakes can exist for years
  • Freshwater ecosystems are vulnerable to climate change; living organisms in the ecosystem cannot survive extreme changes in their habitats
  • Cover 0.8% of the Earth's surface

Brackish Water Ecosystems

  • Salt Content: .05% - 3% or 5,000 to 30,000 mg/L
  • Salinity is more than freshwater, but less than seawater
  • Types or examples of Brackish Water Ecosystems are estuaries, brackish seas, and brackish water lakes
  • Commonly result from the mixture of fresh to sea water (where rivers meet seas)
  • Cannot be used as drinking water because the many contaminated organisms that thrive in the water carry harmful diseases

Salt Water Ecosystems

  • Salt Content: 3% - 5% or 1,000 - 3,000 ppm (parts per million)
  • Types or examples of Salt Water Ecosystems are open oceans, wetlands, or coral reefs
  • The 'open ocean' is the largest marine ecosystem
  • Range from hot to extremly cold temperatures
  • Have come under stress after the increase in population over the decades
  • Cover over 71% of the Earth's surface

Extra Information

  • All aquatic ecosystems are effected by temperature, sunlight, oxygen, nutrients. climate, and location
  • Some animals are able to survive in two or more different kinds of aquatic ecosystems (i.e., Salmon are born in freshwater, but they will migrate to the ocean waters (saltier waters) as they age, once they are ready to reproduce they return to the freshwater to lay their eggs)