5/8/2018. Estuaries are classified by: > Mode of formation e.g. glaciers, deposition, sea level rise. > Patterns of water circulation

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1 Prepared by Diana Wheat-LBCC Compare and contrast the various types of estuaries, including their origin, size, shape, and general location on earth. Distinguish and describe the different types of habitats found in a typical estuary. Evaluate the different types of osmotic capabilities of estuarine species. Discuss threats to estuaries. Summarize uses by humans. Where the Fresh water (rivers & streams) meets the Ocean. Also known as bays if ship traffic occurs there. Salinity and currents fluctuates with the tides. Often an area rich in nutrients. Ecotone of possibly high biodiversity. Also called: Fjords Sound Tide/mud flats Inlets Salt Marshes Estuaries are classified by: > Mode of formation e.g. glaciers, deposition, sea level rise > Patterns of water circulation 1

2 I. Coastal plain Broad and shallow embayments Continuously modified by wave erosion II. Bar-built Formed by a barrier island trapping water near the coast that enters from a river or stream Courtesy of NASA/Johnson Space Center Courtesy of NASA/Johnson Space Center III. Coastal lagoon Large embayment with little freshwater input IV. Delta Estuary with a broad, poorly defined fan-shaped mouth The Mississippi River Delta, showing the sediment plumes from the Mississippi and Atchafalaya Rivers,

3 V. Tectonic Created when the underlying land sank because of crustal movements of the Earth e.g. San Francisco Bay VI. Fjord Estuary that is deeply entrenched into a landform carved out by a glacier Seen in: Norway Alaska Canada Chile Iceland New Zealand Courtesy of NASA/Johnson Space Center Salt marshes Very wet grasslands Include many halophytes Pickleweed, marshgrass, cordgrass A true plant not a seaweed. Contributes to GPP. Habitat for many fish/invertz. Reduce erosion from tides/storms Food for many animals including sea turtles, & marsh herbivores. An area the size of a football field is lost every day on a world wide average. These are areas of refugeand protection including to human interests. 3

4 Mudflats Made of rich, thick mud exposed to air at low tide Include many diatoms, seaweeds, and seagrasses Courtesy of James Sumich Oyster plots on the mudflat in Netarts Bay. OSU research Photo credit: Tiffany Woods, Oregon Sea Grant Channels Always filled with water Include many planktonic, nektonic, and benthic organisms (c) ollirg/shutterstock Crabs, fish, oysters, zooplankton, phytoplankton Estuaries have frequent salinity changes. Animals and plants living in estuaries must have special adaptations. Osmoconformers -body fluids fluctuate with changing salinity e.g. soft bodied epifauna. Osmoregulators animals that regulate to some degree their body fluid composition e.g. crabs 4

5 " There has long been a belief that the sea, at least, was inviolate, beyondman's ability to change and to despoil. But this belief, unfortunately, has proved to be naive." Rachel Carson I.Stenohaline Tolerance to limited salinity ranges - most FW fish, can t tolerate higher salinity and Haddock, can t tolerate lower salinity. steno means narrow. II. Euryhaline Tolerance to a wide range of salinity. e.g. sharks often rely on shallow inshore areas for nurseries including wetlands. Migratory species like Salmon, Herring Withdrawing water at unsustainable rates - Surface and groundwater are being depleted - One-third of the world s people are affected by shortages. Most water (FW) is used in agriculture People also engineer waterways - Dams, levees, diversion canals - For supplies, transportation, and flood control Dredging: Clearing waterways for commerce. Pollution: including plastics, toxins, antibiotics, thermal, organic matter e.g. sewage, oil spills, dioxins Coastal development loss of mangroves, eel grass beds, salt marshes etc. Overfishing 5

6 Shellfish & crab harvesting Fishing especially dredging Mariculture oysters/shrimp Boating sports e.g. kayaking, paddleboarding Cruises for tourists Commerce shipping/bays Bird watching Vacation spots e.g. tropical lagoons NOAA education portal al_estuaries/welcome.html Ocean Blue Project 6