1. Marine Biology
Lecture 7: Estuaries

2. What is an estuary? Definition Biological perspective
“Partially enclosed embayment where fresh and salt water meet.”
Biological perspective
One of the most biologically productive types of ecosystems in the world

3. Types of estuaries in Oregon
Drowned river mouth
River dominated
Bar built
Blind

4. Bar-built estuary
Cape Hatteras, North Carolina

5. Stony Brook Harbor, Long Beach
Bar Built Estuary
Stony Brook Harbor, Long Beach

6. Parts of an estuarine system

7. Salinity profiles
Positive “salt wedge” estuary

8. Salinity classifications (cont.)
Negative (“evaporate”) estuary

9. Effects of tides on salinity

10. Other physical characteristics
Substrate
General description
Relationship to salinity

11. Other physical characteristics (cont.)
Temperature
Wave action and currents
Turbidity
Oxygen

12. Salinity tolerance of organisms

13. Osmoconformers vs. osmoregulators

14. Estuarine food webs Sources of energy Primary consumers Key predators
Organic matter
Phytoplankton
Algal mats
Plants
Primary consumers
Planktovores
Detritovores
Key predators

15. Estuarine food webs

16. Focus: Niche partitioning in birds

17. Prey location tactics

18. Common estuarine animals in Oregon
Worms (a variety)
Clams (a variety)
Snails (in some)
Ghost shrimp (Calianassa californiensis)
Sand shrimp (Crangon spp.)
A variety of crabs
Cancer magister can be found in estuaries, although they are stenohaline and found near the bottom
Predatory fish
Birds

19. Common estuarine organisms in Oregon
Worms: a variety
Abarenicola sp.

20. Common estuarine organisms in Oregon
Saxadoma nutalli: butternut clam
Macoma nasuta: bent-nosed clam
Photos: Melissa Phipps
Protothaca staminia: littleneck
Mya arenaria: soft-shelled clam

21. Common estuarine organisms in Oregon
Snails
Cerithidea sp.: California horn snail

22. Common estuarine organisms in Oregon
Callianassa californiensis: the ghost shrimp

23. Common estuarine organisms in Oregon
Crangon sp.: the sand shrimp

24. Salt Marshes
Mangroves

25. Mangrove prop roots