First Blog
The first two weeks at the Community Farm have gone by. On the second day, Mrs. Saltzmann gave us a lesson on plate tectonics.
“Subduction occurs when a continental…
“There are several types of plate…
“The strike-slip or transform…
“Blah, blah…
Mrs. Saltzmann’s lecture was not like the typical lesson just described. After a short introduction to plate tectonics, she gave us four colored world maps, which displayed age of the seafloor, topography, volcanic activity, and seismic activity, and a blank world map to record observations and inferences on the locations of plate boundaries.
Looking at the topographical map, we noticed the divergent mid-ocean ridges formed thin mountain ranges down the center of the Atlantic Ocean and in other oceans. These ranges had crevices running down the center. Large trenches along Japan and the west coast of South America indicated subduction zones. The tall Himalayas were scrunched up between two colliding plates. I never expected Antarctica to have such high elevation.
Next, we looked at volcanic activity. We noticed a difference between the locations of lower silica and higher silica content volcanoes, although the pattern was not clear. I know the silica content depends on the type of rock, but I need to investigate that further.
The seismic activity represented earthquakes as circles – large earthquakes had larger radius and deeper earthquakes were redder. At the subduction trenches we noticed earlier, earthquakes were common. Interestingly, each trench had a rainbow of earthquakes, with deeper red quakes farther away from the trench, and shallower blue quakes nearer to it. As one plate moves deeper and deeper below another, the quakes that occur at the interface between the plates also move deeper.
Finally, the age of the seafloor maps confirmed the locations of the divergent boundaries, because young rock is formed at the boundary. We observed that the north end of the Pacific divergent boundary was completely subducted underneath North America.
Looking for these patterns is how scientists can discover plate boundaries and other phenomena. Understanding science requires recognizing patterns more than memorizing facts.
The best scientists not only can recognize patterns, but can also use their work to solve society’s problems. Corey Radis, a civil engineering graduate student who is helping at the garden, is part of Stanford Earth Box. This organization is working to build and sell planter boxes filled with sediment from the Searsville Dam. Corey’s job is to test the sediment for nutrients and minerals and to prepare mixtures of the sediment with horse manure, chicken manure, and compost. We will grow basil plants in these various mixtures and compare the plant growth and leaf chemical composition. To do this, Corey will use sophisticated machinery that dissolves and analyzes the sediment and plant samples.
Corey’s experiment reminds me of a science fair experiment, but with better equipment and a useful application. I wonder if the work of other scientists is like that as well. The practical aspect of Corey’s work is much like Roland and Molina’s study of the ozone hole and their efforts to bring awareness to that crisis. Both Corey and the ozone scientists use science to solve environmental issues. In Corey’s case, the issues are urban food deserts and a lack of environmental education in schools.
Scientists must be multitalented and alert people. They need to recognize patterns in a hodge-podge of information, be able to communicate those patterns to others, and draw conclusions from the patterns. But to be a truly effective scientist, a person must be able to see the positive and negative social implications of their work. Einstein, for example, recognized that his theories on matter and energy would lead to weapons of mass destruction. Other scientists go beyond seeing the consequences to applying their work, as Corey and the ozone scientists have done. Science is important, but only if scientists can figure out how to turn dusty old research papers into a difference in everyday life.
Second Blog
Dear Blog,
We walked through dry grass, gnarled coyote brush, and pink clarkias towards the top of Windy Hill Open Space in the Santa Cruz Mountains. This was our geology field trip on July 9th. At the top of the hill, we had a sweeping view of the South Bay. Using compasses, we sighted to various landmarks such as the Dumbarton Bridge and Mount Diablo to determine our location on a map. The compass had a mirror that allowed to accurately pinpoint landmarks. Looking at the Landsat images also showed us the locations of fault lines, including the San Andreas and Hayward Faults, which formed noticeable linear valleys that were often filled with sag ponds.
Our docent also noticed that while the surrounding hills were covered in redwoods, Windy Hill’s vegetation was merely dry grasses and coyote brush. She suspected it could be due to the rock type, which could affect the tree roots, nutrient levels, and moisture content. I also noticed a similar phenomenon in other areas, and I suspected the direction of the slope and amount of fog was affecting the trees. The Santa Cruz Mountains we were standing block fog and cool ocean breezes from reaching Stanford. The range was formed about one million years ago during the Pleistocene as pieces of the crust were pushed upward through fault action.
We piled back into the cars and drove down the other side of the mountains to San Gregorio State Beach to eat lunch. The San Gregorio Fault was just across the highway. We made sketches of the sedimentary rock along the eroded cliff faces. Our docent explained that the mysterious swirling pattern of the rocks, called flame structures, was due to soft sediment deformation. The darker, less dense sediment was first deposited underwater. Then, due to a volcanic eruption, the finer grained whiter ash was deposited above that. Since water saturated both sediments, they acted like liquids, allowing the dark sediment to flow upward. We sat beneath the 2 million year old formation and sketched the rocks. Walking further down the beach, we noticed another interesting interface between two rock layers. Instead of a straight dividing line, pieces of the upper layer had moved into the lower layer. This was due to bivalves that had burrowed into the sediment!
We then traveled south to the Pigeon Point Lighthouse to observe a completely different sedimentary rock – conglomerates. These were formed by a high energy underwater landslide that sent large pebbles down the slope. We examined the pebbles with hand lenses. Geologists can compare chunks found on either side of a fault to determine the amount of offset created by the fault. Adjacent to the conglomerate was a layered formation of red-orange rock and grey, fragmented rock. This was formed by alternating periods of slow deposition for the lighter grey rock and more violent landslides for the red, coarser rock.
Our last stop was Ano Nuevo State Park, a home for sea lions, dolphins, and kelp. While walking along the steep white cliffs, we saw dolphins playing in the ocean. Within the rocks were fossils of shellfish that formed circles and spirals. Ano Nuevo is a mystical place.
Thank you docents, Jenny, and Stanford Earth for the geology trip.
Third Blog
On the past two Tuesdays (7/29 and 8/5), we, the Farm Interns, gave tours to our fellow students. Our first tour stop was the water valve that supplies the Farm. The incredibly clean water comes from Hetch Hetchy, a beautiful valley that John Muir failed to protect from being dammed. Muir stated that we might “as well dam for water-tanks the people's cathedrals and churches, for no holier temple has ever been consecrated by the heart of man”. As a result, using the Hetch Hetchy water for farming is a waste. Luckily, the new Education Farm that is being built nearby will use non-potable water.
As we entered the Farm, we passed by the tool shed and compost pile. The compost is a combination of green vegetation, which contains nitrogen, brown vegetation, which contains carbon, and water. Bacteria, fungi, ants, worms, and insects decompose the plant material and generate heat. To kill weed seeds and harmful bacteria, the temperature of the pile should reach 130 degrees Fahrenheit.
We walked through the outdoor kitchen, passed by the greenhouse and looked at the okra before finally arriving at the chicken coop, where the chickens lay their eggs. Adjacent to the coop is a fenced off area where the chickens eat food scraps, drink water and eat scratch (a seed mixture, or chicken candy). We gave everyone a handful of scratch so they could feed the chickens.
Next was the scavenger hunt. Everyone split up into groups of three or four, and took pictures of okra, peppers, squash, melons, basil, and golf balls. Completion was their ticket to eating pizza!
For the History of Life interns, Erin talked about sustainable agriculture, showed samples of various vegetable seeds, and distributed seed catalogs while the oven heated up. The General interns rotated among several tasks, including cleaning the chicken coop, turning the compost, harvesting basil, and painting golf balls.
At last, our fellow interns had earned their pizza. We showed them how to knead dough, spread tomato sauce, and place fresh toppings on their pizzas. We sat around the table eating, talking, and enjoying the fresh air.
When everyone was full, we completed our last task – soil texture testing on the Searsville sediment. Soil texture is the ratio of sand to silt to clay. To determine clay content, we wetted a ball of sediment and molded it into a pencil shape. The clay content can be revealed by the sediment’s ability to stick together when one picks it up by the center. To find the sand content, we used a pea-sized ball of sediment. Using water, we washed out the lighter and smaller particles, until only sand was left. This allowed us to estimate the percentage of sand. Using a soil texture triangle, we determined that our soil texture was sandy loam.
Showing off the Farm and hosting a pizza party was a satisfying end to the internship. I will miss the Farm and everyone who worked there. Thank you Erin, Corey, Johnny, Elise and Patrick. I will miss you, Ulices, Nisha, Julia and Darren!