INTERN ESTUARY TRAINING June, 2012 Oregon State University Hatfield Marine Science Center

1. INTERN ESTUARY TRAININGJune,2012Oregon State UniversityHatfield Marine Science Center

2. WHAT IS AN ESTUARY? • River meets the sea • Mixing of fresh and salt water • Protected from wave shock • Subjected to tidal influence

4. US Outer Coast Estuaries Cape Flattery – Cape Mendocino 24 - Washington 49 – Oregon 15 – N. California ________________ 89 - total Most are small (< 10 km2) Lee et al. 2006

5. WHY ARE ESTUARIES IMPORTANT? • Juvenile fish traveling from the river to the ocean can adapt to salt water • Eel grass beds provide refuge or nurseries for many fish and invertebrates • Invertebrate and their larva provide food for many species of fish (including salmon) • Provide a stop over for migratory birds • Provides a buffer against floods and tsunamis for the surrounding land

6. PARTS OF AN ESTUARY(based on the proportion of time under water) • Channel under water all the time • Eelgrass beds under water most of the time • Mud flat exposed mid to low tide • Salt marsh covered only at high tide • Uplands always out of the water

7. ESTUARY CLASSIFICATION HOW THEY WERE FORMED 1. Drowned river valleys 2. Fjord 3. Sand bar (or bar built) 4. Delta (Nile river) WATER MIXING 1. Salt wedge 2. Partially mixed 3. Well mixed

8. DROWNED RIVER VALLEYS Less then 10,000 years in age Branching structure of old river systems Contain large areas of mud flats and salt & marshes (wetlands) Great deal of biomass and biodiversity

9. SAND BAR ESTUARY At river mouths where sand or shingle accumulates off shore to form islands or spits May be interlinked islands & estuary systems Generally shallow Siletz bay is and example of a sand bar estuary

11. FJORDS Formed as sea bed rose above glaciated valleys after the last ice age Narrower and straighter then drowned river valleys Less biomass & biodiversity Greater Tsunami hazard May be anoxic at depths

13. SALT WEDGE ESTUARY(highly stratified estuary) Large consistent river flow (Colombia or Mississippi Rivers) Key point: salt water is denser (heavier) then the fresh water which floats in the salt water. The wedge moves up or down the estuary as the tide rises or falls.

14. YAQUINA SALT WEDGE Summer Winter Tidal flow Tidal flow • River flow • River flow

15. PARTIALLY MIXED ESTUARIES More tidal influence and less river flow More turbidity and more ocean/river water mixing Fine sediment settles out and is not washed out to sea as in estuaries with massive river flow, but is deposited in the estuary (estuary surface rises slowly=accretion)

16. WELL MIXED ESTUARIES Tidal flow is sufficient to remove virtually all the vertical salinity differences Tides dominate over the river flow

17. DIFFERENCES BETWEEN EAST & WEST COAST ESTUARIES EAST WEST Rain in winter No snow Fresh water in winter Marine climate Narrow continental shelf Narrower temperature swings Larger salinity changes • Rain in summer • Snow • Fresh water in summer • Continental climate • Wide continental shelf • Large temperature swings • Smaller salinity changes

18. DIFFERENCES BETWEEN EAST & WEST COAST ESTUARIES EAST WEST Most 5- 10,000 years old Smell the ocean (because of the winds) Less diversity & more density with a greater proportion of introduced species • Estuaries below Cape Cod very old (millions of years) • Generally don’t smell the oceans • Greater estuarine diversity with a lower proportion introduced species

19. Winds and current structure • off coastal Oregon: • Winter: • Winds from the South • Downwelling – shore-ward transport of surface water • Poleward-flowing Davidson Current • Uniform cross-shelf hydrography • Spring Transition – sea level drops suddenly • April 4 ± 25 days • Summer: • Strong winds from the North • Coastal upwelling – off-shore transport • Equatorward alongshore transport (California current) • Strong cross-shelf physical gradients • Slide modified from William Peterson WA Winter: 4 6 ° N OR 4 5 ° N Newport 4 4 ° N 4 3 ° N 4 2 ° N WA Summer: 4 6 ° N OR 4 5 ° N Newport 4 4 ° N 4 3 ° N 4 2 ° N

20. YAQUINA BAY & ESTUARY FACTS Area = about 5 sq. miles (relatively small) Watershed = 256 sq. miles (relatively small), 95% of watershed is forest. Two rivers, Yaquina and Elk, contribute to the river flow equally. 70% of estuary water exchanged with each tidal cycle This is a WELL MIXED estuary in summer and a PARTIALLY MIXED estuary in the winter. Yaquina bay is closely coupled to the near shore ocean

21. NUTRIENTS IN YAQUINA BAY • WINTER nutrients primarily from rivers • SUMMER nutrients primarily from ocean • North winds • Upwelling • Nitrates, nitrites & phosphates @ 2 days • Chlorophyll A @ 6 days Summer algae blooms are not pollution or eutrophication but a result of upwelling of ocean nutrients

22. HOW TO TELL WHEN UPWELLING HAS OCCURRED? Sea foam will be on the beach. Water temperature in the bay will drop (this is measured by the LOBO exhibit) Water temperature in the touch tanks may drop Water temperature is a surrogate for measuring Nitrates and Phosphate nutrients!

23. LIFE IN THE ESTUARY • Rocky shore is “2D” • Estuary (or soft bottom) is “3D” • After: Little, C. The Biology of Soft shores & Estuaries

24. ORGANISMS ADAPTATION TO THEIR ENVIRONMENT Rocky “2D” Tide pool Soft “3D” Estuary Lightly armored Live in burrows Good diggers Adapted for low oxygen conditions (anoxia) • Armored • Firmly attached

25. PHYSICAL DIFFERENCES BETWEEN BEACH & ESTUARY Beach Estuary Mud (<63 microns) Water movement by tidal flow (less energy) Salinity 40 = to 0 Sediment deposition coarser mud more near channel • Sand (>63 microns) • Water movement by wave energy (high energy) • Salinity 35 • Sediment deposition coarser sand higher on shore

26. Mud includes both silt and clayAfter: Little, C. The Biology of Soft Shores & Estuaries From Little, C. The Biology of Soft Shores & Estuaries

27. HYPOXIA • The #1 problem for estuary infauna!!! Surface Oxygenated mud Hypoxic mud This line moves up in summer and down in The winter. WHY?

28. BLACK MUD 1. Sulfates Desulphovibrio Hydrogen sulfide (H2S) (present in hypoxic mud) (sulfate-reducing bacteria) (clear & colorless, but foul smelling) • H2S + Iron oxides Iron sulfide (black) (present in the mud) 3. Iron sulfides Beggiatoa sp.Elemental sulfur (from equation 2 ) (oxidizes) (white or yellow patches on the surface of the mud flat)

29. DEALING WITH LOW OXYGEN Hypoxia is a bigger problem in the mud than the sand. Why? Hypoxia is worsened by accumulated organic material. Why? Animals (and plants) in the estuary must be able to cope with low oxygen. How?

30. COPING MECHANISMS They can move (fish, shrimp, crabs, etc.) They can form a water current in their burrows (ghost shrimp, mud shrimp). They can trap oxygenated water from high tide in their shells (clams). They can reduce their respiratory rate (cockles). Some can absorb oxygen from the air if the mud dries out (some cockles). Some (Callianassa/Neotrypaea sp.) oxidize sulfides into thiosulfates (a much less toxic compound)

31. SALINITY GRADIENT From Little, C. The Biology of Soft Shores & Estuaries

32. TYPICAL YAQUINA HIGH TIDE SALINITY AFTER; Yamada, Sylvia (Nov. 8, 1997)