Author Question: The intertidal zone represents one of the most stressful environments in terms of changing ... (Read 118 times)

rachel9 · **on:** Aug 22, 2018

The intertidal zone represents one of the most stressful environments in terms of changing environmental conditions. Explain this comment using specific examples of stresses and how organisms are able to survive in the intertidal zone.

Question 2

Explain why salt marshes and estuaries are among the most productive of marine habitats.

CourtneyCNorton · **Reply #1 on:** Aug 22, 2018

Answer to Question 1

First, organisms must deal with changing water levels between low and high tide. They must also withstand the force of crashing waves. Freshwater runoff and rainfall can cause osmotic shock to organisms adapted to saltwater. In sand or cobble beaches, movement of the sand grains and cobbles creates even more problems. Rolling sand is abrasive to small organisms, and capillary forces can trap small organisms between the grains. The motion of cobbles battered by waves and trap and crush organisms between them.

Answer to Question 2

As the water is very shallow, there is plenty of light for photosynthesis (including vascular plants), and river flow brings a constant supply of nutrients. The gradient of salinity-from the fresh river water to the seawater-helps create a large number of niches.