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SF Carbon Cycles, Humans & the Climate
Guest Speaker: John Wick
7:30pm, Thursday, Feb 19th, 2015
FREE at the Randall Museum, 199 Museum Way, San Francisco, CA 

John Wick, Co-founder of the Marin Carbon Project, is making great strides in organizing around soil carbon sequestration with everyone from the ranch house to the White House.Come hear what you can do, what the city is doing now, and how the Randall Museum will be part of a demonstration project on carbon cycling.

We’ll discuss the whole carbon cycle with an eye to making informed changes in our management of carbon: human nutrition, organic waste streams, soil health, water, wealth & economics, and carbon credit protocols.

Darwin, whilst voyaging in Patagonia, was one of the first to observe the impact of invasives, but it wasn’t until 1958 with Charles Elton’s the publication of “Ecology of Invasions by Animals and Plants” before much thought was given it. And only in the 80’s — during a conference on mediterranean climates, where speaker after speaker talked about invasives — that the study of invasions became a field of study.

Nowadays it occupies the attention, resources, and budgets of many organizations, where invasive organisms threaten to displace natives. Lew Stringer (on January 15th, 2015) talked to us about what is involved in trying to make the Presidio and other places free of 3 weeds in particular: iceplant, mattress weed, and english ivy.

A view of Lobos creek. The area most covered in mattress weed was off to the left of the frame.

Ice plant, Carpobrotus edulis, known in it’s native South Africa as sour fig, or hottentote-fig (it’s fruit is edible) has been in California for 150 years. It arrived in California with the intercontinental railroad, where the rail builders were using it to stabilize railroad levees, and in the 40s and 50s, CalTrans decided to use it for the highways now crisscrossing the state. People thought it was pretty, and soon it was being planted everywhere, and now can be found in pretty much every Mediterranean region.

For years now, up & down coast, people have been working on removing it. The Presidio has little left, mostly removed by hand over the years. It’s a labor intensive project, but easy to keep out. Point Reyes, has done it through various methods, but is soon to embark on a 3 year project using herbicides.

Mattress Wire Weed, Muehlenbeckia complexa, or mattress vine (and a host of other vines) is from New Zealand where it grows in little clumps on dunes. Here, much like Kudzu, it blankets trees and shrubs, and vaults up trees and smothers them. It was first observed in 1971 on the North Coast. No one is sure how it came, but likely through gardening — it makes for great shrubs and topiaries.

In the Presidio, it ended up blanketing a couple creeks (one which was only rediscovered in the 90s): Lobos and Dragonfly. Under the Mattress Wire Weed at Lobos Creek, they found tunnels under the canopy it was so dense. Both of the creeks have been largely restored to native habitats, but you can still find big piles of the weed at Sutro Baths.

English Ivy is the big fight that remains in the Presidio — with an attempt to remove it in the historic forest, and replace it with other understory. The ivy was brought over from the Canary Islands in 1875 by a horticulturalist who was very excited by ivys. But it what we refer to as English Ivy is likely a swarm of species and it is likely a hybrid species. Hybrids are some times especially successful and the term hybrid vigor refers to this. It has become a problem in the Sierras, in redwood forests, and grows in a abundance under the eucalyptus on Mt Sutro.

It is particularly hard to remove. It only produces seed when it leaves the ground. Weeders will cut the ivy at the base of the tree, so it is no longer reproductive. From there it is hard work. Although having a herd of goats can help — it takes vigilance to keep it from coming back.

All this work to keep back invasives is both time and budget intensive. And it is becoming more controversial — especially where the removal of trees comes into play — and some people beginning to question whether it is worth it, looking at the novel ecosystems that form. Hawaii has seen a huge loss of species to invasives, but its overall diversity has not changed much. Not that that is always the case, take Sutro forest, for instance, which has low biodiversity because of the dominance of eucalyptus and english ivy.

It is clear that invasions will keep happening, including more insidious ones like sudden oak death and other plant pathogens, some organizations are working on early detection networks and rapid response before things get out of control. We can look forward to continued discussion around the value of native plants, planted forests, and resistance to unwelcome plants. In the meantime, we can enjoy some of the wonderful landscapes in the Presidio that Lew has helped uncover.

Joe Jordan led us on a glorious tangent filled romp through the sky — chasing rainbows and other phenomena with photos, chalkboard drawings, and props.

Joe, former physicist NASA, current director of the Sky Power Institute (http://www.sky-power.org) talked to us at the Randall on November 20th, 2014 about all manner of sky phenomena and the physics behind them: the complexities of rainbows, sun dogs, sun pillars, moonbows, haloes, glories, contrails, green flashes, castles in the air, the directionality of meteor showers, and more!

A lot of what we see looking up, or what we see downwards looking out of a plane is the result of ice crystals in the air, their orientation to the sun, and the observers particular perspective.

Sun pillars for instance — where a column appears to rise from the setting sun — is sunlight reflecting off the undersides of ice crystals. It is the same effect as the sun reflecting off the waves toward you, just in the sky. Other effects depend on the angle that light is hitting the crystal, and where that crystal is in relation to the light and you.

A more complicated phenomena, but one of my favorites, are glories. Sitting on the shadow side of the aircraft — as you are coming into land and passing over clouds, you might see a glory in the clouds, a circular rainbow. At the center of that you might be able to make out the shadow of the aircraft.
(If you are a SCIAM subscriber you can read more at http://www.scientificamerican.com/article/the-science-of-the-glory/)

Joe talked a fair amount about the appearance of sun rays fanning out. Sun beams are essentially parallel given the distance the travel from the sun. The fanning out is an optical illusion akin to how train tracks look when we look down them.

We spent the longest time with the intricacies of rainbows, the bending of light through raindrops and how that gets to our eyes. Multiple bounces leads to double and triple and more rainbows (in the lab, this has been done up to the 15th order, but in nature you’d be lucky to see a 5th order rainbow).

My favorite factoid of the night is that although what we see a rainbow as a static thing up in the sky, what that rainbow actually is is an animated mosaic projected onto our eyes — millions of rain drops bending light in our direction, changing colors until they fall “out of the picture.” followed and replaced by the raindrops above.

Double Rainbow!

The Most Extreme Storms Yet
Guest Speaker: Joel Pomerantz
7:30pm, Thursday, Mar 19th, 2015
FREE at the Randall Museum, 199 Museum Way, San Francisco, CA 

Joel will share his research on the weather disaster that determined so much of what’s around you today. In early 1862 the sky dumped upwards of ten feet of rain in the mountains (about four feet in San Francisco). In the middle of that, there was a hard freeze for a week down to sea level. Thousands died. No previous research has done so much to connect the dots. Come learn about the widespread disaster that spanned more than four states (before all were states), changed the course of rivers, destroyed the California economy and brought in invasive grasses, among other stunning details.

(notes by Joel) Geologist and plate tectonics animator Tanya Atwater spoke to us October 16, 2014. She gave us her presentation called Living in the Plate Boundary and Through the Ice Ages.

The presentation was largely based on diagrammatic animation videos which these notes cannot describe. But you can see them yourself on Atwater’s website  (or you can Google Atwater animations). I apologize that I wasn’t as able to take notes as usual since my eyes were up on the video screen a lot.

The surface of the earth is made of plates floating on (and diving down thousands of miles into) the earth’s molten mantle, which is always flowing.

When you look at the animation of the continents coming into their present formation, India seems to move faster than the rest. This is partly due to the size. Smaller means it can move faster. Of course the speeds are all pretty slow, taking many millions of years. (Speeds are similar to how quickly a fingernail grows, according to Julian’s talk back in July.)

The Himalayas are uplift (crumpling and wrinkling of the plate that pushes the surface up). This is due to the direct-hit crunching of the Indian plate against the plate to its north.

The Pacific Plate is the largest plate, taking up almost 1/3 of the surface of the earth. It’s being dragged past the North American Plate to the NW, scraping against it and at the same time leaving bits behind along the edge.

The area west of North America has been for a long time (until recently) made up of three ocean plates. Ocean plates are formed by spreading mid ocean rifts where mantle magma wells up in the gap. (Continental plates are formed by uplift, by volcanos, by wind and glacial deposits, etc.) The two plates on the east side of the rift zone have flowed under the Americas now (a process called subduction). There’s a tiny bit left of one (Juan de Fuca Plate) in Oregon and North California Coastal waters and a little (of the Farallones Plate) near Central America.

As the rift spreads, the Pacific Plate gets bigger on its east side faster than it moves northwest. That means it grows and seems to come closer while in fact it is moving away. The direction of movement is not directly away, but scraping NW along our coast, pulling our coast out and stretching the North American continent. That’s why the high areas that used to be Utah and Nevada had room to collapse and fall over becoming the basin and range provinces with lots of gaps between high ridges. It’s also why the Gulf of California has opened up.

The San Andreas

Tanya’s graduate thesis was to try and figure out the San Andreas Fault, which turns out to be a unique fault over the whole earth.

If a slipping fault is a perfect line in the direction of slip, it has no gaps or places that push against each other (forming wrinkles, i.e. hills). But in reality, all places have some kinks, so there are hills and gaps formed.

Pinnacles Park in California has a very different kind of volcanic rock. Rocks the same have been found hundreds of kilometers away so we know that one side of the slipping fault moved that far since the eruption.

Bodega Head has granite that has moved up from Southern California, 500 km, as do a few other spots on the Northern California coast.

About 25% of the motion of the fault’s energy is spread into the Tahoe region in smaller stresses. In 10 million years, there will be an ocean alongside Las Vegas, because the Pacific Plate will have dragged what is now California away, probably.

Subduction

Before the San Andreas, we had a subduction zone as the ocean rift pushed plates under us. The mid ocean ridge where the spreading areas were is now mostly under us. A subduction pretty much has to be along a straight line. When the subduction hits the melting point (not from friction but from the internal heat of the earth) it bubbles up through the plate above it. That is why there are volcanos in the Cascade Mountain Range. It’s the Juan De Fuca Plate coming back up. Some is trapped under and that becomes granite. Some makes it to the surface and is lava. That lava flowed to the coast and was crumbled and tossed into a mixer of rocks, seawater, etc, some of which was dragged back down by the subduction to enter the whole cycle again and again. Meanwhile, some of the rubble of this cycle is left on the edge of the North American Plate. This is the accretionary wedge.

Other geographical features

The Great Valley (a.k.a Central Valley, San Joaquin Valley, etc.) is the collected debris of the volcanos and cycles of subduction at the edge of the continent. The land west of it (the coast range) is the uplifted part of that debris (cause by bends in the slipping fault pushing mountains up) mixed with melange of things dragged along from elsewhere. The melange is blue schist and chert and all sorts of stuff.

The Transverse Ranges (Tehachapies) that curl toward the coast are granite like the Sierra Range, but the farther south you go the more deeply eroded it is, so the farther under the formation you are looking. The granite in places like Joshua Tree Park are not smoothed into canyons like the Sierra’s because there were no glaciers to scrapes and smooth them. They formed rounded boulders instead.

The L.A. basin is deep and filled with mud.

Between Santa Barbara and San Diego there was a break and a gap opened. The land that was there got pulled and rotated. It is now the block of material that the Channel Islands and Santa Barbara sit on. It tumbled and was rotated to its current position by the two plates grinding past one another within a gap where the coast was pulled out allowing for rotation. Geologists can tell this is so, even though it is unlikely, because the rocks formed with their magnetism lining up with the poles. Now it points east in all those areas, so they know by paleomagnetism studies that the whole section pulled apart and rotated.

Ice Age

The present sea level is about as it has been since the last ice age ended 6,000 years ago. It’s melt from the ice age glaciers. The maximum of the ice age was about 17,000 years ago after tens of thousands of years of ice age. We are now in an interglacial period. The previous one was about 100,000 years ago, and they happened in the past about every 100,000 years. Ice ages always come on slowly and end quickly.

As the glaciers melt quickly, the sea level rises a lot. (For the most recent, between 300 and 400 feet all around the world at once.) Each place where a sea level remained a while, the wave action cuts a terrace on the edge of the continent. By the time the sea level goes gradually down and then quickly back up the next time, the continent has risen some distance, so the next wave terrace is below the old ones. This eventually forms a stair-step coast line. The older steps are more eroded but they are highly visible even to the untrained eye.

If there is a lot of sand in the waves, it takes up the wave energy, but if not, the energy cuts new terraces.

There was so much more she said!

Sky Phenomena
Guest Speaker: Joe Jordan
7:30pm, Thursday, Nov 20th, 2014
FREE at the Randall Museum, 199 Museum Way, San Francisco, CA 

Rainbow above the golden gate

Joe Jordan will come back with new material after having really wowed and inspired our audience with his slides on this topic in 1997.

Joe will show pictures of all kinds of atmospheric phenomena, including rainbows, haloes, glories, aurorae, coronae, mirages,
and the legendary (but real) “green flash”.   He’ll bring along some hands-on 3-D models (to go along with his descriptions
and explanations) that might help us understand what causes some of these things, and where and when to watch for them.

As an added treat, Joe will regale us with information and stories on a recent focus of his — the science, technology and politics, behind clean energy (“sky power to the people” — see his TED talk on it – shown below!) — including the scientific basis for a big public-art sculpture idea.

Ice Plants, Mattress Wireweed & Other Onslaughts
Guest Speaker: Lew Stringer
7:30pm, Thursday, Jan 15th, 2015
FREE at the Randall Museum, 199 Museum Way, San Francisco, CA 

Have you seen how much of our coastal parkland is now covered in succulent ground cover, hardy New Zealand vines, and just too many highly invasive species? Come hear Lew give us the low down on ground cover invasive plants. He’s been working with the Presidio Trust, and before that the Golden Gate National Recreation Area, to develop strategies to manage the various species that would take everything over if they managed themselves.

Ice plant (Carpobrotus edulis) in Muriwai sand dunes

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