Intertidal Zonation

Intertidal Zonation:
In Puget Sound the tidal heights from lowest low to highest high vary approximately 16 feet maximum in Seattle, 22 feet at Olympia.  The farther south into Puget Sound the greater the tidal range due to the restricted water area of South Sound.  This is a moderate exchange compared worldwide.  The greatest exchance takes place in Canada's long Bay of Fundy (52 ft.), while some in Alaska are over 30 ft. as are the tides at the northern end of the Sea of Cortez in Baja, Mexico.  Hawaii sees only tidal exchanges of a few feet.  (for readers outside the U.S.A. please excuse our inability to switch to the metric system) :).
Animals, seaweeds and sea grasses are affected by the constant rise and lowering of the tide.  While some intertidal organisms are adapted to withstand wide ranges in salinity, heat, light, and drying others are less adapted.  Some species a restricted to tidal areas where predators or competitors are not too great a threat.
In short, two factors determine which organisms live where in the intertidal:   Biological and Physical.
Animals well protected from drying, UV radiation, cold, and excessive heat can thrive in the highest intertidal levels...being able to take long naps doesn't hurt either.  Highest living barnacles may be able to feed only a few hours per month, napping the remaining time away...the ultimate couch potatoes.  Most intertidal sea stars have heavy complete hard skeletons to protect from excessive water loss during low tide exposure.
Intertidal crabs are almost exclusively flat in shape to allow easy access to damp spaces under rocks where they spend the low tide protected from drying and predators above....you know, the gulls.
So if you should happen to turn over small rocks, make sure you turn them gently back to their original position to protect the critters living under and attached to the bottom of the rock and living on the top of the rock....better yet turn over few or no rocks.
For additional information a slide show presentation can be accessed under ZONATION in the BUZZ LINKS section.

EELGRASS

                                                 EELGRASS, THE RICH MEADOW

Eelgrass habitat is highly important to many species in Puget Sound.
There is a new link  in the BUZZ LINKS section to Eelgrass which will take you to a slide presentation on the subject.

Oil Pipeline Goldmine

Did you know that the frequency of occurrence, in the gut of the Penpoint Gunnel, of Gammaridea is 51.14% while the frequency of Harpacticoida is only 13.64%?  You didn't?  Shame on you.  :)

                                                        Oil's Golden Result
In the 1970's there was building pressure to build an oil terminal in Northern Puget Sound to handle oil from Alaska, and there was push back.  At the time there was almost a complete lack of economic and environmental information about the North Puget Sound Region.  In 1974 Washington State initiated the North Puget Sound baseline study through the Department of Ecology which was designed to evaluate the oceanographic, biological, and economic resources of the region.  One result was the publication EPA-600/7-79-259.  Food Web Relationships of Northern Puget Sound and the Strait of Juan de Fuca.

The opening question can be answered by checking out the contents of the above publication....and the great thing is you can download it for free at :  http://www.epa.gov/nscep/index.html
This website is a real gold mine of publications on marine life, of Puget Sound and other areas...as well as all kinds of other EPA publications.

Food Web Relationships of Northern Puget Sound and the Strait of Juan de Fuca.
This publication above all is the one I recommend if you want to know who eats whom....and all about food webs.  It covers; invertebrates, fish, birds, mammals.....the whole caboodle.  Download it and you will have one of the best references available on Puget Sound marine life.

Eggs of the Intertidal

Eggs found in the intertidal are often the most difficult items to indentify.  Seattle Aquarium Beach Naturalists have been equipped with ID sheets to make the life easier but for others perhaps this group of images will be of some use.  New image:  illustration added at bottom of Pile Worm eggs...these egg masses are often found floating in the drift in summer and have been a mystery for some time.  This ends up as a clump of dirty tan eggs about the size of a jumbo chicken eggs....individual eggs are not visible without a microscope.  Will try to add image of actual egg mass next time I see one.

Things to Remember:

Arthropod females hold eggs and release hatched larvae (crabs, barnacles, shrimp).

Echinoderms broadcast spawn and do not attach eggs (a few Sea Stars retain eggs till they hatch)

Most worms broadcast spawn some lay attached eggs.

Some Mollusks broadcast spawn....(chitons, limpets, some snails).

Fish often attach eggs (Scuplins, Herring, Lingcod, Smelt) others broadcast spawn (Cod, Flounder) or have live births (Dogfish Sharks, Perch, Rockfish)

Cnidarians mostly broadcast spawn or divide asexually or retain eggs and release tiny adults                    

 BEACH EGGS

Frilled Whelks laying eggs

Dungeness Crab with eggs

Gravid Tidepool Sculpin

Unidentified Polychete worm eating Bubble Shell Eggs

Gravid Tidepool Sculpin

Northern Kelp Crab with eggs

                             

Spinyhead Sculpin male with eggs

Sea Lemon laying eggs

Barnacle Eating Nudibranch with eggs



Big Skate eggs in egg case

Black-clawed Crab with eggs

Bubble Snail with eggs

Bubble Snail with eggs

Burrowing Sea Cucumber with eggs

Gumboot Chiton laying eggs

N. Clingfish with eggs

Crescent Gunnel with eggs


 


Ghost Shrimp with eggs

Green Annelid worm eggs

Green Annelid worm that laid eggs above

Graceful Cancer Crab with eggs

Lacuna snail eggs on eelgrass

Plainfin Midshipman eggs

Plainfin Shipman male with eggs

Moon Snail with egg case (sand collar)

Hairy Triton with eggs

Red Octopus with eggs

Giant Pacific Octopus with eggs

Sculpin eggs

Shaggy Mouse sea slug with eggs

Sea Star female spawning

Sitka Shrimp with eggs

Taylor's Sea Hare eggs

Frilled Dogwinkle with eggs

Sea Lemon sea slug eggs

Opalescent Sea Slug with eggs

Opalescent Sea Slug eggs on Moon Snail sand collar

Frilled Whelk egg capsules

Frilled Whelks mating

Rockweed Isopods mating

Aggregate Anemone dividing

Emarginated Whelk egg capsules

Flatworm and egg masses

Rockweed Isopod with young at pouch

Rockweed Isopod with young at pouch

Plainfin Midshipman eggs

Porcelain Crab with eggs

Lacuna Snail with eggs

Hairy Shore Crab with eggs

Noble Sea Lemon eggs

Lacuna Snail eggs

Lacuna snail with egg mass on shell

Pile Worm eggs