3. Salt Wedge-Description
• Low density FW overrides high density SW
• Can extend far upstream
• Impacted by tides
– Flood (incoming) – wedge is further upstream
– Ebb (outgoing) – wedge is less far upstream
– Because of it, organisms here must deal with
major salinity fluctuations
4. Substrate (bottom sediments)
• Rivers:
– Current is too fast to let sediment drop out
– Lots of suspended (floating) material
• Estuaries:
– Wider sides, area where water flows opens up (gets
wider) so water is slowed down
– Once flow slows suspended sediments drop out
– Result: estuaries are usually muddy
• Closer to Oceans:
– Currents are stronger
– Smaller particles are washed away leaving larger
sediments behind
