Crater Lake

This month is six years since my visit to fabulous Crater Lake National Park in Oregon. America's deepest lake at nearly 2000 feet in depth, it sits inside the collapsed caldera of an ancient volcano. Wizard Island near the west side of the lake is a volcano within a volcano. The lake is fed entirely by rain and snow. The amount falling in each year is nearly equal to what evaporates of leaks out the bottom. Crater Lake is what I can only describe as being impossibly blue. Pictures don't do it justice.

Crater Lake seen from West Rim Drive

In addition to the lake, the park also features forests, wildflower meadows, waterfalls, pumice deserts, cinder cones, and formations called pinnacles. The pumice deserts were formed by volcanic eruptions depositing pumice. Like sand, it drains very well so there is little moisture retained in the ground. Like in a true desert, only the hardiest plants can scratch out a living. 

Pumice desert

The pinnacles were originally volcanic steam vents. As gas and steam were released, moisture mixed with the surrounding ash and formed a thick cement. Mount Mazama, the ancient volcano that formed Crater Lake, had its last major eruption 7700 years ago. Following a massive eruption of ash and pumice, a huge explosion caused the mountain to collapse into itself. 

Wizard Island, a caldera within a caldera

Red Cinder Cone, a shadow of the volcanic past

While visiting Crater Lake, I got to do a bit of exploring. I started a sunset hike up The Watchman, one of the peaks along the crater's rim. I got turned around by an incoming thunderstorm. On another hike across the pumice prairie and through a burned forest, I turned around when I lost sight of the horizon with more storms in the forecast. I went down into a canyon along a mountain stream and back up, saw the pinnacles, a waterfall, and small meadow with varying degrees of wetness. Different wildflowers were growing in different areas due to elevation, soil, and moisture levels- a great example of zonation.

Some of the wildlife in the park includes Clark's nutcracker, golden mantled ground squirrels, mule deer, black bears, foxes, bobcats, and pika. I was lucky enough to see the ground squirrel, deer, gray jays, and a tiny frog.

After leaving Crater Lake, I headed to the coast and stayed at the Oregon Dunes. There was no activity at the Sea Lion Caves nearby. The next stop before going home was a quick visit to Mount Hood. I stank after a week in the woods without showers, but the adventure was worth it. This week's information comes from USGS and NPS. All photos are my own. I'll be taking a break for vacation and will return in September with a look at some hard workers, just in time for Labor Day.

Glossary of Terms

Here at Nature minute, we use a lot of big words, or even just smaller words you've probably never heard before. It's a fine line between going over your head with technical terms and dumbing it down too much. In the interest of walking that line, here are some of the words you might hear thrown around the office or in the field.

Alluvium- eroded sediments, deposited on land by water. Areas are sometimes referred to as "alluvial plains"; these are where the soil is made up of mostly alluvium.
Benthic- the bottom of a body of water. A river bed and the sea floor are benthic zones, or benthos. Benthic also refers to the organisms living in the benthos.

These insect larvae are benthic creatures

Brumation- a state of lowered metabolic activity in cold-blooded animals; it is similar to hibernation.
Crepuscular- active around dawn and dusk. Deer are crepuscular mammals.

Deer being crepuscular in my back yard, circa 2015

Epiphyte- plants which grow on other plants, but are not parasitic. In the Pacific Northwest, ferns often grown in trees.

Epiphytic ferns

Ephemeral- seasonal. During the spring melt, ephemeral streams and waterfalls form in the mountains.

Ephemeral waterfall cascading down a hillside

Fossorial- digging species which live mainly underground. Moles and badgers are fossorial mammals.
Hadal- the deepest oceanic zone. Deep sea trenches are the hadal zone.
Littoral- the nearshore zone of a body of water, from the high tide line to the shoreline.

This horseshoe crab is in the littoral zone

Torpor- a state of lowered metabolic activity and body temperature in warm-blooded animals. Like brumation, it is similar to hibernation.
Transpiration- water exhalation by a plant. Water is lost as vapor through pores in the leaves.
Ungulate- mammals with a hoof. They come in 2 orders: Artiodactyla, which have an even number of toes, and Perissodactyla, which have an odd number of toes. Those crepuscular deer are ungulates.

Getaway Islands

Summer is here and for many people it's the perfect time to relax at the beach. If you're at an East Coast beach, odds are you're on a barrier island. The Atlantic barrier islands extend from Canada to Florida, then up Florida's Gulf Coast and all the way around to Mexico. Prior to development, many of these islands came and went at the whims of the tides and storms. Now that we've built homes and resorts on them, there is a vested interest to make them more permanent by using jetties to block the outflow of sand and beach replenishment to restore what's been lost. Let's take a look at the natural history of where you built that sand castle.

Grassy dune in New Jersey

Barrier islands, if left to nature, live and die by the tides. Ocean currents carry sand away from the islands. The sand either moves out to the sea floor, where it can be brought back to the island by currents, or it is carried to another part of the island or to a different island. Strong storms can accelerate the process, wiping islands off the map or opening up a new inlet to the back bay.

Hurricane Irene cut these inlets across Hatteras Island (NOAA) 

Barrier islands can move toward the mainland as wind blows sand over the dunes to the bay side. The marshes fill in with sand and build up new dunes, while ocean moves to where the dunes originally were and new marshes form in the bay on the edge of the old marshes.

Salt marsh at Assateague Island (NPS)

The islands are important because they are barriers protecting the mainland from such storms. A few weeks ago we looked at hurricanes on this blog. Barrier islands absorb the brunt of the storm surge that comes in ahead of the hurricane. Developed barrier islands still absorb the storm surge, but not as well as undeveloped islands from times past. Impermeable surfaces like roads and parking are terrible at absorbing water, while sand drains quickly. If the dunes have been removed from an island, the storm surge rushes right over top with nothing but buildings to slow it down.
Barrier islands are also important as habitat for critters other than summer vacationers. On an undeveloped island, different plants and animals that can tolerate different amounts of salt water and exposure to the air make their homes in different zones. Clams live beneath the sandy shore, while birds that prey on them scurry above. Grasses hold the dunes in place, and at the highest points of the island you can find trees and shrubs where songbirds and mammals live. Brackish marshes on the other side of the dunes host crabs and serve as a nursery where fish can eat and grow before venturing into the open sea. Wading shorebirds take advantage of this bounty. Beyond the marsh is the back bay and the mainland.

Ghost crab (NPS)

Sandpiper feeding frenzy

The US has more barrier islands than any other country in the world. Best known are New York's Fire Island, Texas's South Padre Island, the Outer Banks of North Carolina, and the Jersey Shore. If you spend a summer weekend at the beach, be sure to check out the wild side of things.
This week's information comes from Science News for Students.

In the zone

Nature loves order. A place for everything, and everything in its place. This week we take a look at zones, nature’s sorting bins.

Every species has its habitat, which is where it lives and what it consumes. It also has a range, which is the geographical limits of where it and its habitat exist. On a more local scale, the habitat and range occur in a zone of an ecosystem.

Even though it’s bitter cold outside (at least where I sit), let’s revisit the beach we explored at Labor Day. We examined the sea creatures one several different rocks. There were many species there: mussels, starfish, anemones, and barnacles just to name a few. They all share the same habitat (beach) and while they may have different ranges (British Columbia to northern California vs Alaska to Baja for instance), at this location their ranges overlap.

Soft-bodies sea life at the lowest exposed rocks at low tide

Hard-shelled sea life in the highest exposed rocks at low tide

But notice that the species on one rock are totally different from those on another, even though they are separated by a distance of just a few dozen feet. The rocks are in different zones. Starfish and anemones are on rocks that are farther away from the high tide line, and those species are more sensitive to the drastic changes in tide. Closer to the high tide line you’ll see the mussels, snails, and barnacles. They are hardier and can withstand exposure to dry conditions much better. Also, notice that those three all have a hard outer shell, while the starfish and anemones don’t. Think there might be a connection between zones and defensive adaptations?

Not all zones are at the beach. Take a drive up to Mount Rainier with me this summer and I’ll show you how the forest changes as we go up in elevation. The dense western red cedar, Douglas fir, and western hemlock give way to mountain hemlock, pines, and Pacific silver fir right on up to subalpine fir scattered throughout mountain meadows. The taller trees are at lower elevations, while higher up the trees are stunted and warped by the short growing season and heavy snow cover. Even the air smells different in the different zones. Marine and aquatic environments also have different zones according to depth and the amount of light that reaches them.

Western red cedar, western hemlocks, and Douglas fir at about 3500 ft above sea level

Subalpine fir at about 5500 feet above sea level

Ocean zones from Marine Biodiversity wiki
http://www.marbef.org/wiki/open_oceans

Zones can change by elevation, depth, and latitude, or a combination. Douglas fir can be found at higher elevations in the southern Cascades than in the northern Cascades. Zones can also change over time, not just space. Forest zones change as trees grow and die, or in the case of disturbances such as fire. Next time you are out and about, look around for changing zones around you!