The Difference Between a Freshwater & Saline Water Ecosystem

An ecosystem is the aggregate of all biological, physical and chemical properties typical to the abiotic and biotic components of an ecosystem. Biotic components are the living parts of the ecosystem while abiotic components are the non-living parts of the ecosystem. Differences between saline and freshwater ecosystems include size, salinity and species.

Salt Content

• The marine, saline or salt-based ecosystem is an aquatic ecosystem. It is called a saline ecosystem because of the water's high levels of salt content. According to the Environmental Protection Agency, the average marine water has a salinity level of 35 parts of salt to one kilogram of water. This is one of the major differences between the saline and freshwater ecosystems. Freshwater ecosystems have very little salt content and are the main sources of drinking water.

Types of Saline Ecosystems

• Saline and freshwater ecosystems comprise different types of bodies of water. The saline ecosystem is divided into estuaries, coral reefs and oceans. Coral reefs -- like the Great Barrier Reef off Australia -- form barriers along continents. Estuaries are the point of convergence between marine and freshwater ecosystems while oceans are large bodies of water in different parts of the world.

Types of Freshwater Ecosystems

• Freshwater ecosystems include ponds, lakes, streams and rivers. Ponds may be natural or man-made. Some natural ponds, like sessile pools, are seasonal and only last for a few months, unlike saline ecosystems, which are permanent. Streams and rivers are bodies of water flowing toward one direction. They start from headwaters -- which could be lakes, springs or melted snow -- and flow all the way to their mouths, which may be an ocean.

Size

• Another major difference between marine and freshwater ecosystems is their size. Marine ecosystems are huge and they make up about three-fourths of the Earth's surface. Freshwater ecosystems are small in comparison to their marine counterparts. Oceans -- the largest bodies of water -- are separated into four zones. The intertidal zone is the junction for the ocean and land. The pelagic zone is the open ocean. The benthic zone is the area directly underneath the pelagic zone and the abyssal zone is the ocean's deepest regions.

Species

• The species of organisms found in marine and freshwater ecosystems vary. All of the species of organisms in the marine ecosystem have adapted to survive this ecosystem's high salinity. For example, most fish in this region have special gills that help them regulate their salt intake by filtering out excess salts. On the other hand, organisms in the freshwater ecosystem do not have this physiological adaptation because it is not necessary.