FNR 45400 Lecture 11: Environmental variables

• School: Purdue University
• Department: Forestry and Natural Resources
• Course: FNR 45400
• Professor: Goforth

Document Summary

There are many important environmental variables that influence estuaries, such as salinity, seasonal variability, sediment, do, and temperature. Salinity isn"t the most important factor in estuaries, but it does influence the survival and distribution of estuarine organisms. The range is often the greatest mid-estuary region. Organisms are classified by their salinity tolerances as either stenohaline or euryhaline. Salinity is subject to both spatiotemporal and longitudinal variability. Spatiotemporal variables could be seasonal characteristics, while longitudinal variability refers to the differences in salinities in different parts of the estuary. At the river"s end, a salinity of 0 is common, while at the estuary"s mouth a salinity value of 34 is common. The changing salinity also is influenced by the tides with higher salinities ending up near the bottom of the river and lower salinities gliding over top of them. This is beneficial for infauna species because they can sustain the variability in salinities by burrowing down into the sediment.