Tuesday, June 19, 2012

Yaquina Estuary

I had the opportunity to spend about 5 hours learning about the Yaquina Estuary today, including getting REALLY muddy on the mud flats at low tide at 6:30 in the morning, and me without rubber boots.
Our guide's feet sinking in the mud

It was awesome!  (Yes, mud and all.)  We also got to take the "estuary walk" tour given by a Hatfield Marine Science Center visitor center master docent, and also watch a power point about estuaries.  Grand total: 14 pages of notes.  Don't worry, I won't transcribe them all here.  You're welcome.

Estuary overview
What are the characteristics of an estuary?
  • Place where the river meets the sea
  • Mix of fresh and salt water
  • Protected from wave shock
  • Subject to tidal influence
Why are estuaries important?
  • Juvenile fish travel from the river to the ocean and can adapt to the salt water
  • Eel grass beds provide refuge or nurseries for many fish and invertebrates
  • Invertebrates and larvae are food for many other organisms
  • Provides food and stopover for migratory birds
  • Provides a buffer against a tsunami
 Yaquina Estuary specifically:
  • 5 square miles
  • watershed of 256 square miles (which is relatively small)
  • 95% of watershed is forest
  • 70% of water is exchanged during each tidal cycle
  • Well mixed estuary in summer - most of the water is coming from the ocean
  • Partially mixed estuary in winter - most of the water is coming from the river (wet season)

Here are some cool things we found on our mud flat adventure:
Polychaete (segmented worm) - Phylum Annelida

Mud shrimp (we found these all over the place, and collected a few)

This is a molt which I collected and am hoping will dry well so I can keep it

Our guide, Dr. John Chapman, expert in invasive species

This is the mud flat a few hours later after the tide came in
This picture above is a waxy kind of salt plant called coyote bush.  It's similar to many plants in the dessert.  Plants that live in the salt marsh have to have special adaptations to survive the salinity.  This plant does it by preventing evaporation, just as it would if it were in the dessert.  But here, instead of the evaporation being caused by heat, it would be caused by salt.

Bill showing us the groove on a snail which indicates it as a predator

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