What is the main difference in the water that is in freshwater ecosystems, estuaries, and marine ecosystems?

1 Answer
Aug 22, 2016

Salt

Explanation:

Freshwater, although not found in pure form (100% H2O), contains less salt. Estuarine water contains some salt but not as much as sea water. Of course, location to location sea water salt content is different. For example, Baltic Sea has 8 per thousand salt but Black Sea has 30 per thousand salt.

According to Stumm and Morgan (1996), river and seawater ions are:

Sodium 0.00023 M (river) 0.47 M (seawater)
Magnesium 0.00015 M (river) 0.053 M (seawater)
Calcium 0.00033 M (river) 0.010 M (seawater)
Potassium 0.00003 M (river) 0.010 M (seawater)
Chloride 0.00016 M (river) 0.55 M (seawater)
Sulfate 0.00007 M (river) 0.028 M (seawater)
Bicarbonate 0.00086 M (river) 0.0024 M (seawater)

Reference: Stumm, W. and Morgan, J.J. (1996). Aquatic Chemistry: Chemical equilibria and rates in natural waters (3rd edition). Wiley, New York, NY, USA.