Week 3

Date: 19 and 20 April
Weather: rainy and cold; then cloudy and cool
Location: Olympic Peninsula, specifically Lake Crescent and Salt Creek

Over the weekend we went up to the Olympic Peninsula to visit Lake Crescent and the surrounding forest as well as the Salt Creek tide pools.

Thumbnail sketch of Lake Crescent

To the left is my thumbnail sketch of the landscape at Lake Crescent. Although the fog made it a little difficult to see the hills in the distance, the valley is U-shaped, which is typical of glacially carved valleys (this particular area was shaped by the Fraser Lobe of the Cordilleran icesheet). V-shaped valleys are usually carved by rivers. Since glacial movement went from north to south, any geologic formations in this area run north-south.

The section of the lake I was observing had vegetation (coniferous trees) down to the waterline, which indicates that the water level at that point has stayed pretty constant. Lack of vegetation near the edge of the water would have indicated previous flooding that would have killed off vegetation close to the waterline. The water was pretty clear, still, and very deep, up to 1000 feet deep in some places. Because the lake contains so much water, it has too few nutrients to support very much life. However, there is one species of fish endemic to it that is also landlocked into it-- the beardslee trout. The trees in the foreground of my drawing are red alders.

Young forest, characterized by little development of the understory.

We also went into the forests and observed the different types of flora and fauna (black-tailed deer, pacific wren, varied thrush, townsend warbler, to name a few) there. The area we were in was almost technically a rainforest but not quite(only 10 inches under the definition's threshold). We saw a clearly distinct line in the forest where trees were not mossy, and then where they did become mossy, indicating a change in forest vegetation and thus structure and processes. I thought this was pretty cool and interesting that the divide would be so pronounced, rather than gradual. Various tree species we saw included western red cedar, douglas-fir, grand fir, big leaf maple, and western hemlock. In general, the phenology of the plants here was behind that of the ones in Ravenna because of lower temperatures in the National Park than in the city. We were also able to see the difference between young and old forests, where old forests are characterized by B.U.N.S., or big trees, understory development, nurse logs, and snags.

Western red cedar with cool moss/lichen, not sure what type it is
(this is not the tree that went through the fire disturbance). This tree species
is well adapted to fire and has high changes of surviving fire disturbances.
It also is decay-resistant.

One particular western red cedar we saw near the trail had survived a fire disturbance. Its trunk was hollowed out and blackened but the overall tree was still living. While its support structure is less stable, it can still cycle nutrients through its length and thus remain living. Fire disturbances like this cause drastic effects not just to individual trees (Douglas-firs that have gone through fires will often have charcoal fire-scars on their trunks) but to the overall forest structure as well. Sometimes fire will go through the forest in a mosaic pattern, leaving behind biological legacies like nurse logs, which provide habitat. Immediately after a fire disturbance, early successional species like red alders, shrubs, and opportunistic species will begin to grow. While old-growth habitats are key to the survival of many types of organisms, early seral conditions are also important as they provide diverse habitats to important species. Middle successional species may include douglas-firs, which are not shade-tolerant, and thus take advantage of the sunlight they can access in this stage of forest development. In late seral conditions, douglas-firs may die off perhaps because of butt rot or wind disturbance. After this happens, western hemlocks, which are shade-tolerant, take advantage of their new access to sunlight and begin to take over the stand. Douglas-firs cannot grow back after this point, unless another disturbance fells the western hemlocks.

Limpets (oval-shaped shells; organism is
inside) and barnacles on rock.

The second day we went to the Salt Creek tidepools where I saw some pretty cool organisms. For instance, I saw fingered limpets-I don't think these are common in Maine- so it was interesting seeing them everywhere. They are pretty much wherever dall's acorn barnacles are, although the two species do compete with each other for space. Bob Paine mentioned that limpets will bulldoze barnacles out of their way and that sometimes you can see the trail they leave behind. This was interesting to me because I have always thought of barnacles as non-mobile, stubborn creatures, and because limpets look like they wouldn't necessarily need/want to move around either.

Dall's Acorn Barnacles; the bigger ones
in here were about 3/4 of an inch long

The barnacles here are up to two inches in length--this size is not common in the places I frequent in Maine, so it was cool to see such large ones. Their shells have adapted to become sharp for protection against large predators. Some snails can drill through their shells however. They also close up so that during low tides when they are not in the water, they can preserve their moisture.

Pacific rockweed algae

Green ribbon algae

Though I didn't see any oyster-catchers, I learned that you can tell where their territory is by where algae grows. Oyster-catchers eat barnacles, and barnacles eat algae. So if a barnacle population on a rock is eaten by oyster-catchers, there are no more algae predators, and the algae can grow more. This is an example of a ripple-effect in this ecosystem.

Unsure of this algae too,
but it has a cool texture that reminds me of
tire tracks, or textured plastic

Sea lettuce in foreground, unsure of algae in background,
perhaps deflated Pacific rockweed algae?

Unsure of what algae this is

Further out on the beach there was a huge pile of broken and empty mussel shells which was evidence of predation. Sea birds that eat mussels will often fly above rocks and drop mussels onto the ground to break the shells to access the meat inside. This seems to have been a prime location for such activity.

Other organisms we saw included mossy chiton, emarginate dogwinkle, pacific littleneck clam, edible mussels, california mussels, red crabs, pacific blood star, ochre sea star, and tidepool sculpin.

Finally, I think I may have also seen a false sea lemon, but at the time I didn't know such a creature existed, and I thought it was just an actual lemon under a rock- this would be common in the nature that I experienced as a child, where people threw away their food scraps on the beach for the seagulls to eat. Consequently, I didn't think about it too much and didn't bother to investigate- it was partially under a rock too- but flipping through my Audubon book later made me wish I had!