Estuaries

Estuaries are partially enclosed coastal bodies of water Examples of estuaries include: –River mouths –Bays –Inlets –Gulfs –Sounds Formed by a rise in sea level after the last Ice Age

Southern California Watersheds

Classifying estuaries by origin Coastal plain Fjord Bar-built Tectonic

Examples of estuaries Pu‘uloa

Examples of estuaries Fjord estuary (Norway) Tectonic estuary (San Francisco, CA)

Coastal wetlands Coastal wetlands are saturated areas that border coastal environments Brackish water conditions Two most important types of coastal wetlands: 1.Salt marshes (mid-latitudes) 2.Mangrove swamps (low latitudes)

Coastal wetlands: Salt marshes and mangrove swamps

Salt Marshes are dominated by dense stands of halophytic (salt-tolerant) plants such as herbs, grasses, or low shrubs.

These plants are terrestrial in origin and are essential to the stability of the salt marsh in trapping and binding sediments.

Infauna: live within the sediment, mostly soft bottom; mostly clams and worms (polychaetes) burrow tubes for food scavenging and oxygen supply Primary producers: algae, mostly benthic diatoms and dinoflagellates cyanobacteria mats on mudflats mud more productive than sand macro- and meiobenthos, often detrivores, living of deposits from seagrasses and marshes birds important grazers

32,000 polychaetes in sand/m2 vs earth worms in soil/m2 Ecological Role: clean sediments aerate soil

Found from the Arctic to Southern Australia Salt marshes grow in muds and sands that are sheltered by barrier islands. Flood and ebb currents transport saltwater, nutrients, plankton and sediments in and out of the marsh.

Salt marshes play a large role in the aquatic food web and the exporting of nutrients to coastal waters.

They also provide support to terrestrial animals such as migrating birds as well as providing coastal protection