1. Estuaries & Salt Marshes1 Estuaries and Salt Marshes Essential Nursery Habitat

2. Estuaries & Salt Marshes2 Estuaries Dynamic habitat where two aquatic systems meet

3. Estuaries & Salt Marshes3 Types of Estuaries Estuary classification can be based on basin topography or salinity gradients. Topography Drowned river valleys or coastal plain

4. Estuaries & Salt Marshes4 Bar-built Estuary Sand bars Barrier islands NC

5. Estuaries & Salt Marshes5 Tectonic Estuaries Subsidence San Francisco Bay

6. Estuaries & Salt Marshes6 Fjords Retreating glaciers Sill

7. Estuaries & Salt Marshes7 Salt Wedge Positive Estuary (high tide)

8. Estuaries & Salt Marshes8 Salt Wedge Positive Estuary (low tide)

9. Estuaries & Salt Marshes9 Negative Estuary Inverse estuary High salinities > 50‰ 100‰ or more during dry spells

10. Estuaries & Salt Marshes10 Abiotic Factors of the Estuary Varying Salinity Substrate Varying Temperature Currents Turbidity Low Oxygen Levels

11. Estuaries & Salt Marshes11 Abiotic Factors Salinity Tides Topography Wind Evaporation Precipitation

12. Estuaries & Salt Marshes12 Physical Factors Substrate Rivers carry large amounts of sediment How is sediment particle size determined by current velocity? How is sediment oxygen concentration governed by sediment size?

13. Estuaries & Salt Marshes13 Living in the Mud

14. Estuaries & Salt Marshes14 Temperature & Currents Temperature Varies more due to smaller volume of water and fresh water input Water temperature also varies vertically Wave action and currents Waves are minimal due to protection Currents are caused by the tides and river flow

15. Estuaries & Salt Marshes15 Turbidity & Light Penetration Turbidity The amount of solid particles suspended in the water column Increase turbidity can decrease the amount of light which effectively penetrates

16. Estuaries & Salt Marshes16 Oxygen Where fresh and salt water mix there is ample oxygen in the water column Oxygen solubility does vary with the temperature (seasonal) of the water

17. Estuaries & Salt Marshes17 Salinity Tolerances

18. Estuaries & Salt Marshes18

19. Estuaries & Salt Marshes19 Flora Composition Macroflora is limited due to unsuitable substrate and increased turbidity The dominant vegetation is emergent plants Occur in the upper intertidal

20. Estuaries & Salt Marshes20 Types of Estuarine Communities Open water

21. Estuaries & Salt Marshes21 Mud flats Most animals are infauna and are usually feeding on detritus Deposit feeders also oxygenate the sediment with their burrows

22. Estuaries & Salt Marshes22 Salt Marshes Found bordering temperate, subpolar estuaries and marine embayments These are communities of emergent grasses, or low shrubs rooted in soils that are alternately inundated and drained by tidal action Halophytes

23. Estuaries & Salt Marshes23 Salt Marsh Flora & Fauna Dominant plants Spartina, Juncus, Salicornia Dominant animals Crabs (Uca), mussels, oysters, smaller crustaceans, amphipods, juvenile fish

24. Estuaries & Salt Marshes24 Salt Marsh Productivity Most productivity is carried out by the marsh plants and microalgae Productivity is very high due to the emergent plants (Spartina) Very few herbivores, most of this productivity is not directly consumed

25. Estuaries & Salt Marshes25 Mangrove Forests Mangals Tropical equivalents of salt marshes Emergent Intertidal

26. Estuaries & Salt Marshes26