Final answer:
The tidal movements in estuaries rapidly change the salinity, affecting organisms that adapt by temporarily ceasing feeding and switching between anaerobic and aerobic respiration, and estuarine plants that are specially adapted to these salty conditions.
Step-by-step explanation:
The daily movement of a salt wedge due to tidal rhythms significantly affects the organisms living in an estuary. During high tides, the influx of salt water increases the salinity of the estuary, causing many resident organisms, such as mussels and clams, to cease feeding and close their shells to switch to anaerobic respiration, which is energy-intensive but essential for survival in low oxygen conditions.
The low tides reverse this, decreasing salinity, and allowing these organisms to open their shells and resume aerobic respiration and feeding once conditions are favorable.
Additionally, estuarine plants (halophytes) are adapted to tolerate these changes by employing salt filters in their roots or pumping oxygen into their roots to cope with the fluctuating salty conditions.