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The Sierra snowpack is California's largest single reservoir of fresh water, accounting for 1/3 of the state's water supply1. A state with a mediterranean climate, such as California, receives precipitation only during the short rain/snow season. During years of drought, when the average Californian frets about how little rain is falling, state water managers are keeping a worried eye on the amount of snow falling in the Sierra. Snow surveyors use remote sensing and field measurements to estimate the water content of the snowpack. The snow water equivalent on 1 April is used to compare snowpack water content across years.

The 2016-2017 snow year was a productive one, dumping near-record amounts of 'Sierra cement' on the mountains. (Skiers accustomed to the powder snows of Utah and Colorado often disparage the heavy snow in the Sierra, but Sierra cement carries a lot more water than powder so is much more beneficial to the state's water supply). Most of that snow eventually melts, births streams and rivers, and flows from the mountains to lower elevations. After a good snow year, though, snow fields remain at high altitudes even during high summer. That definitely is the case around Lake Tahoe.

A few days ago my husband and I hiked from Carson Pass to Big Meadow, a through hike about 8 miles long. The hike goes through some gorgeous alpine meadow, with an absolutely stunning display of wildflowers. Even in late July we had to cross several streams and saw lots of snow.

Round Top Mountain, viewed from meadow above Carson Pass
25 July 2017
© Allison J. Gong
Snow field in the high Sierra
25 July 2017
© Allison J. Gong

If you look closely at the bottom photo, you may notice some faint pink streaks on the face of the snow field. This pink snow is called 'watermelon snow' because of the color. It is a phenomenon that occurs only at high altitudes or polar regions in the summer. Here's a closer look, taken with a 70-200 mm lens that I rented for the week.

Watermelon snow
25 July 2017
© Allison J. Gong

Given the color of those streaks, you'd think the organism producing it would be a red alga of some sort, wouldn't you? I did, too, until I did some research and learned that it is a green alga! Chlamydomonas is a genus of unicellular green algae, most of which are indeed green in color because the only photosynthetic pigments they contain are chlorophylls. However, Chlamydomonas nivalis also contains reddish carotenoid pigments that serve to shield the cell's photosynthetic pigments from excess radiation, which is intense at the high altitudes where the algae live. The pigments absorb heat, which increases the melting of snow in the immediate vicinity and provides liquid water that the algae require. Watermelon snow is found in alpine regions across the globe, although it isn't known whether or not the same species of alga is responsible in all cases.

Cross-country skiers and snowshoers pass through these areas in the winter, and never report seeing watermelon snow. What happens to the cells in the winter? Do they die?

It turns out that the alga persists year-round, although in different life history stages. Given the inhospitality of their habitat, most of the life cycle involves waiting in a dormant stage, with a short burst of activity in the spring. The red form that we see in the summer is a dormant resting stage, having lost the pair of flagella possessed by swimming unicellular green algae. These spores, former zygotes resulting from fertilization, are non-motile and cannot escape to deeper snow to avoid UV radiation, so they use carotenoids to serve as sunscreens. They are not dead, though, and continue to photosynthesize all summer. They rest through the winter and germinate in the spring, stimulated into activity by increased light and nutrients, and flowing water. Germination involves the release of biflagellated cells that swim to the surface of the snow, where at least some of them function as gametes. Fertilization occurs, with the resulting zygotes soon after forming the resting spores that result in watermelon snow.

It may seem strange that this organism spends most of its time in a dormant stage, but this is not at all uncommon for things that live in hostile habitats. When conditions for life are difficult, the best strategy can be to hang out and wait until things get better. Chlamydomonas nivalis does this on a yearly basis, as do many of the marine unicellular algae. And some animals, namely tardigrades, can dry out and live for decades or perhaps even centuries in a state of suspended animation, returning to life when returned to water. As with many natural phenomena, this kind of lifestyle seems bizarre to us because it is so unlike how we do things. But if C. nivalis could observe and think about how we live, it would no doubt consider us inconceivably wasteful, expending enormous amounts of energy to remain active at times when, clearly, it would much more sensible (from C. nivalis's point of view) to sleep until better conditions return.

 


1 California Department of Water Resources

1

I am fortunate to live in a place of great natural beauty. While the Pacific Ocean dominates much of the landscape, we are also partially surrounded by mountains. I grew up in the flatness of the San Joaquin Valley, a couple hours' drive from both the sea and the Sierra Nevada but not near enough for either to have any appreciable effect on daily life. When I first moved here from the Sacramento area to start graduate school, I felt claustrophobic because I had been used to looking out in any direction and being able to see for miles around. I've long since grown accustomed to the fact that the only miles-long vistas we get are over the ocean and have come to appreciate the proximity of the mountains.

Here we are ideally situated so that ocean and mountain forest are close enough that both can be explored in a single day. And in fact, I did just that the other day, on Boxing Day. The elephant seal (Mirounga angustirostris) breeding season has started, and I wanted to go up to Año Nuevo State Park to see them. Alas, this idea didn't occur to me soon enough to purchase tickets for the docent-led tour to the elephant seal reserve area, so we didn't get close to the seals. But it was a gorgeously clear day and the scenery was every bit as spectacular as you'd expect from this part of the coast.

Año Nuevo Island lies a short distance to the southwest off Año Nuevo Point and is reachable only by kayak. The island is a marine wildlife refuge closed to the public, uninhabited by any humans except scientists. Elephant seals, northern fur seals (a type of otariid, or eared seal), rhinoceros auklets, western gulls, and Brandt's cormorants all breed on the island. California sea lions don't breed on the island, but several thousand use it as a haul-out site throughout the year. During the elephant seal pupping season white sharks come to the waters around the island to feed on pups as they learn how to swim.

Año Nuevo Island, viewed from Cove Beach at Año Nuevo State Park.
26 December 2016
© Allison J. Gong

It is not common for the air to be so clear. Usually there is fog or haze that obscures the buildings. There used to be a lighthouse on the island; the dilapidated tower was pulled down in the early 2000s to safeguard the wildlife. Some of the other buildings--a 19th century residence and foghorn station--are currently used as research facilities.

View to the west from Cove Beach.
26 December 2016
© Allison J. Gong

Even without a ticket for docent-led tour of the elephant seal reserve area, you can hike to the staging area from where the tours depart. The trail passes a freshwater pond that is home to two endangered California herps: The red-legged frog (Rana draytonii) and the San Francisco garter snake (Thamnophis sirtalis tetrataenia). Years ago I had a colleague in graduate school who studied the elephant seals up at Año Nuevo. I went in the field with him one day and got to wear the special blue research windbreaker. He told me that before being allowed to drive into the reserve area all of the researchers have to take a driving test that involves not running over plastic snakes that are placed in the road. This is to make sure that the endangered snakes won't be inadvertently killed.

Freshwater pond at Año Nuevo State Park.
26 December 2016
© Allison J. Gong

We ate lunch at a lookout point of the tour staging area. Because the air was so clear we could see quite a way down the coast. Highway 1 as it passes under the cliffs immediately north of the Waddell Beach is visible at the far right edge of the photograph.

View towards Waddell Beach from Año Nuevo.
26 December 2016
© Allison J. Gong

After lunch we headed away from the coast and drove up Gazos Creek Road a few miles into the forest. It took all of about 15 minutes to go from beach to redwood forest. How cool is that? Two completely different ecosystems to explore easily within a day. Even the weather was different: sunny and warm at the beach, much cooler and damper among the trees.

Although we were up in the redwoods, this day I was fascinated by all of the moss growing on the trees. We've had a decent amount of rain so far, and the forests are satisfyingly wet and squishy. The creek we followed had washed out a bit of the road in a couple of places, and was closed to all traffic about 5 miles from the highway.

Moss-covered tree along Gazos Creek.
26 December 2016
© Allison J. Gong

We didn't have a lot of time to poke around in the forest, but since we were in the area we stopped at Rancho del Oso on our way home to visit my favorite tree. Rancho del Oso is at the bottom of Big Basin Redwoods State Park. I take my ecology students there for the first field trip of the semester, because there I can introduce them to two of the ecosystems that define the natural history of Santa Cruz.

My favorite tree is a coast live oak (Quercus agrifolia) that lives just off the trail at Rancho del Oso. I love its gnarled branches that grow horizontally at ground level. It is an old, wise tree. Looking through its branches you see into the redwood forest of Big Basin. I normally photograph this tree at a different angle, looking into the forest away from the trail. This day I decided to shoot it from an angle parallel to the trail. I don't think it's quite as dramatic from this angle but there's no denying the magnificence of the tree.

Coast live oak (Quercus agrifolia) at Rancho del Oso.
26 December 2016
© Allison J. Gong

Rancho del Oso is also the downhill terminus of the Skyline-to-the-Sea trail. The entire trail is about 30 miles, and most hikers take two or three days to hike the whole thing. I'm not much of a backpacker but one of the things I'd like to do this spring is the day hike from Big Basin down to Rancho del Oso. Doesn't that sound like great fun?

In recent years the day after Thanksgiving has become known as Black Friday, a day when retailers across the nation offer fantastic sales in order to separate Americans from their hard-earned cash. I hate shopping even under the best of circumstances, and you couldn't pay me enough to step foot in a shopping mall on Black Friday. Fortunately, a trio of organizations have put together about the most awesome alternative to Black Friday that I could imagine. They call it Green Friday.

The idea behind Green Friday, as I understand it, is to get people to spend the day after Thanksgiving outdoors enjoying nature instead of fighting over $5 t-shirts at some big department store. The three organizations--Save the Redwoods League; the California State Parks Foundation; and the California State Parks--sponsored some number of free parking passes at the state parks. I have a Golden Poppy pass, which gets me into state parks in northern California and we didn't need one of the free passes, but I've been wanting to go hiking up in Big Basin so I rounded up my husband and a few friends and off we went.

Big Basin Redwoods State Park is the oldest state park in California, established in 1902. It has long been my favorite of the state parks I've visited.

Big Basin sign

I have to say, the Green Friday thing seemed to be working. The park was very crowded, with lots of families. We chose to hike the Sequoia Trail, a 4-mile loop that begins at the park headquarters and goes past Sempervirens falls, a monument to the founders of the park, and a treacherous passage called Slippery Rock. The oldest and tallest redwood trees in the park are seen from the Redwood Loop trail, which we didn't hike this time. But it is impossible to see any redwood forest, and not feel awed.

Redwood forest in Big Basin Redwoods State Park. 25 November 2016 © Allison J. Gong
Redwood forest in Big Basin Redwoods State Park.
25 November 2016
© Allison J. Gong
Looking up at redwood trees (Sequoia sempervirens) in Big Basin Redwoods State Park. 25 November 2016 © Allison J. Gong
Looking up at redwood trees (Sequoia sempervirens) in Big Basin Redwoods State Park.
25 November 2016
© Allison J. Gong

The oldest of these trees have outlived multiple human civilizations. It's humbling to be surrounded by such ancient beings.

The forest floor is shaded by the canopy of the redwood and other tall trees. At this time of year, and especially after a rain, the understory is spectacular with greenery and life. It's all about the mushrooms. California had four dry winters before last year's El Niño rains, and so far this autumn has been fairly wet. Well, October was wet; we didn't have rain in November until last weekend. The fungi have been biding their time, waiting for enough water to fall from the sky before sending up their fruiting bodies. Now, I freely admit that mushroom identification is a major weak spot of mine, so take these names with a grain of salt. But I'm learning! The duff on the ground in the area we hiked was a mixture of redwood needles and leaves from tan oak (Notholithocarpus densiflorus) and California bay laurel (Umbellularia californica). Many mushrooms were growing directly through the duff, while others were growing on living or dead trees.

Ramaria sp. in the redwood forest in Big Basin Redwood State Park. 25 November 2016 © Allison J. Gong
Ramaria formosa(?) in the redwood forest in Big Basin Redwood State Park.
25 November 2016
© Allison J. Gong

This so-called coral mushroom is, I think, Ramaria formosa. We saw a few clumps of it right at the beginning of the hike, in this pale orange color. The branching at the tips appears to be more or less dichotomous, and the overall shape and size of the body reminded me of the intertidal rockweed Pelvetiopsis limitata.

These really pretty bracket fungi may be turkey tails (Trametes versicolor). We found lots of them on both dead and living trees. The ones that are brilliant orange and brown I do recognize as turkey tails, but when they're pale and creamy like these I'm not sure whether or not they're the same thing.

Bracket fungus (Trametes sp.) growing on a dead log.
25 November 2016
© Allison J. Gong

And there were spectacular displays like this:

25 November 2016 © Allison J. Gong
25 November 2016
© Allison J. Gong

and this:

25 November 2016 © Allison J. Gong
25 November 2016
© Allison J. Gong

and this:

25 November 2016 © Allison J. Gong
25 November 2016
© Allison J. Gong

and strange things like this:

25 November 2016 © Allison J. Gong
25 November 2016
© Allison J. Gong
Clavaria fragilis, or fairy fingers 25 November 2016 © Allison J. Gong
Clavaria fragilis, or fairy fingers
25 November 2016
© Allison J. Gong

I was able to identify those strange white things as Clavaria fragilis, or fairy fingers. The mycelium of this fungus lives underground in grasslands and wooded areas; it is described as common in this area, especially during the wetter months. The arrangement of these fruiting bodies in a more or less straight line is interesting and makes me wonder if the mycelium is living in a log buried under the duff. I don't know what else would cause the mycelium to grow in such a linear fashion.

My favorite mushroom photo of the day was of these LBMs (little brown mushrooms) that were growing out of a downed redwood. The mushrooms themselves are extremely cute, but what I really like about this picture is the bokeh. I've become intrigued by the practice of composing and exposing photographs so that the the non-subject matter is deliberately blurred and becomes part of the overall aesthetic quality of the image. I think I've noticed it before, but never really thought about how to achieve it. Practicing it is a whole lot of fun, and I think there will be many more photos like this in my future.

LBMs (little brown mushrooms) growing on a redwood log 25 November 2016 © Allison J. Gong
LBMs (little brown mushrooms) growing on a redwood log.
25 November 2016
© Allison J. Gong

Where there are mushrooms there are mushroom predators such as banana slugs. I think we counted about 10 of the bright yellow gastropods on our hike. Alas, none of them were copulating. But one of them was eating a mushroom!

Banana slug (Ariolimax sp.) eating a mushroom. 25 November 2016 © Allison J. Gong
Banana slug (Ariolimax sp.) eating a mushroom.
25 November 2016
© Allison J. Gong

What a great afternoon it was! Given how crowded the park was I'd say that Green Friday was a success. I'd so much rather see people hiking or at least spending time outdoors than shopping for material things. I hope that Green Friday is here to stay!

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