ED41A-0076
Geologic Investigations of the Marin Headlands, California
The Marin Headlands has a unique geology formed by a convergent plate boundary, where the Farallon plate subducted beneath the North American plate. This process formed igneous, sedimentary, and metamorphic rocks. We can see these rocks today because the San Andreas fault, which formed when the North American and Pacific plates collided, pushed up the rocks. We examined the Headlands to learn more about the rocks and their structure. We hiked around many trails, including the Kirby Cove trail. While on the trails we observed the rocks we found and identified four units. The four units that we observed were (1) chert, which is sedimentary, layered, and very-fine grained; (2) greywacke, which is also sedimentary, light brown colored, with a medium to coarse grain size; (3) basalt and (4) diabase which are both meta-igneous, green, and have crystals (the difference being that basalt is extrusive with smaller crystals and diabase is intrusive with larger crystals). While gathering information on the types of rocks, we made a geologic map including the strike and dip of the rocks. We interpret the rocks at the Marin Headlands to represent ancient oceanic crust upon which chert was deposited. The greywacke was deposited later, as the oceanic crust got close to the continental margin. All of these rocks were extensively folded and fractured as they were added to the continent as part of the material in a subduction zone. In conclusion, the Marin Headlands is a very special place to study a part of the diverse geology of California. http://sf-rocks.sfsu.edu
ED41A-0077
Three Dimensional (U-Th)/He Constraints on the Exhumation History of the Shawave- Nightingale Horst Block, Northwestern Nevada
We present data from the northwestern Basin and Range Province that provide constraints on the along-strike variation in slip distribution on the Granite Springs Valley fault as well as three-dimensional constraints on the exhumation history of the Shawave-Nightingale horst block. Through the application of coupled apatite-fission track (AFT) and apatite (U-Th)/He (AHe) thermo-chronometry we have determined that an episode of rapid slip (6- 8km) on the fault and exhumation of the granitic block occurred between ~13-8Ma. Combined with data from a more southerly transect and through morphometric observations of the general topographic expression of the range, we are able to delimit that the greatest amount of slip on the fault is coincident with the Juniper Peak transect in the central Shawave Range. The overall distribution on the fault is highest near this central part of the range and is distributed asymmetrically along strike with less relief in the southern termination of the fault and the least exhumation at the very northern termination of the fault. Recent paleo-seismic investigations of the Granite Springs Valley fault document a minimum of two Holocene slip events of ~2-3m along the entire (~60km) length of the range front fault that occurred simultaneously along fault strike. These data are exciting because this is the first three-dimensional application of thermo-chronology to the problem of Basin and Range fault propagation and slip history. Our geologic data support an asymmetric slip history that is in contrast to well-documented simultaneous Quaternay rupture and implies that the fault grew asymmetrically as typically modeled for the normal fault growth but at some point in time, or at some critical fault length, the entire system of range front faults was connected and now currently slips at a constant rate along the length of the range. This holds strong implications for considering geologic vs. geodetic strain rates and for delineating seismic hazard in the region. Data presented here are, in part, a product of the diligent efforts of students, Briana Hall and Arian Weinert through their participation in the Stanford School of Earth Sciences High School Internship Program, Summer 2007 mentored by Caroline S. Whitehill. http://pangea.stanford.edu/outreach/
ED41A-0078
Sustainable Seas Intertidal Monitoring Project at Duxbury Reef
The Sustainable Seas Student Monitoring Project at the Branson School in Ross, CA has monitored Duxbury Reef in Bolinas, CA since 1999, in cooperation with the Farallones Marine Sanctuary Association and the Gulf of Farallones National Marine Sanctuary. Goals of the project include: 1) To monitor the rocky intertidal habitat and develop a baseline database of invertebrates and algal density and abundance; 2) To contribute to the conservation of the rocky intertidal habitat through education of students and visitors about intertidal species and requirements for maintaining a healthy, diverse intertidal ecosystem; 3) To increase stewardship in the Gulf of the Farallones National Marine Sanctuary; and 4) To contribute abundance and population data on key algae and invertebrate species to the national database, LiMPETS (Long Term Monitoring Program & Experiential Training for Students). Student volunteers complete an intensive training course on the natural history of intertidal invertebrates and algae, identification of key species, rocky intertidal ecology, interpretation and monitoring techniques, and history of the sanctuary. Students conduct two baseline-monitoring surveys three times per year (fall, winter, and late spring) to identify and count key invertebrate and algae species. Seasonal abundance of the algae species Mastocarpus and Fucus revealed lower populations in the spring monitoring events. Turban snails, Tegula funebralis, also showed dramatic population variation with respect to tidal zone. One of our project goals is to monitor this area long enough to obtain trends and to begin to connect these patterns to contributing factors (specific weather events, anthropogenic impacts, etc). Replicate counts of all species are regularly performed. Replicate counts for invertebrate and algae species within the same quadrat along the permanent transects revealed a very small amount of variability, giving us confidence that our monitoring program is providing reliable data. The Branson School 39 Fernhill Rd. Ross, CA 94957 (415) 454-3612 x 323 Farallones Marine Sanctuary Association, PO Box 29386 San Francisco, CA 94129, 415-561-6625 x 303
ED41A-0079
An Environmental Health Assessment: Fecal Coliform Contamination in San Francisco Waterbodies
Fecal coliform is a group of bacteria that exists in the digestive system and excrement of warm-blooded animals. It enters aquatic environments through fecal contamination of water. In the urban environment, contamination can occur not only by direct input from warm-blooded animals but also from storm water run-off and municipal sewer overflow. Fecal coliform itself does not cause disease but it is an indicator of the presence of pathogens that exist in the wastes of humans and animals that are a hazard to human health. We examined 12 locations in San Francisco for fecal coliform and recorded the types of human contact with water at each location. We found low levels of coliform in areas open to the San Francisco Bay and Pacific Ocean and high levels of coliform in inland lakes and ponds. Using Environmental Protection Agency guidelines for fecal coliform concentrations, we found all sites at acceptable levels for the recreational and human activities we observed. http://sf-rocks.sfsu.edu
ED41A-0080
Environmental Analysis Focusing on Nitrate and Phosphate of Lake Merced, San Francisco, California
Lake Merced is located in the southwest region of San Francisco. The lake is used for recreation by many San Francisco residents, is home to many animals and plants and is an emergency water source for the City of San Francisco. We analyzed the lake for nitrate and phosphate concentrations to determine the ecological health of the lake. High levels of these chemicals increase the risk of eutrophication. Our study finds that the amount of each chemical is below maximum contaminant levels (MCLs). We tested for arsenic, chromium, copper, lead and zinc and found that only arsenic and lead were above the MCL. Additionally, we identified the soils and sands, tested the soil for nitrate and phosphate levels at two sites near large amount of wildlife. We also identified the native and invasive plants around the lake and found that the lake contains a majority of invasive plants. Our overall results show that the lake is healthy but could be improved. http://sf-rocks.sfsu.edu
ED41A-0081
A Water Quality Study: Heron's Head Park, San Francisco, California
Heron's Head Park, formerly known as Pier 98, is a 24-acre restored wetland, owned and operated by the Port of San Francisco and situated at the base of the Hunter's Point Power Plant. Heron's Head is a unique environment that is built on landfill and is now a thriving marsh maintained primarily by youth and community volunteers. Adjacent to the park stands a PG&E power plant (closed May 2006), a county waste transfer station, and a combined sewer overflow (CSO) pipe. The park is bordered by San Francisco Bay on the north, east and south sides of the park. We examined the levels of ammonia, nitrite, nitrate, phosphate and fecal coliform at nine sites around the park. Utilizing historical data from other San Francisco Bay sites and other similar estuarine settings in California, we assessed the health of the Bay waters surrounding the park. We found the levels of ammonia, nitrate, nitrite and phosphates to be within the parameters of historical San Francisco Bay data and similar to settings such as Elkhorn Slough, Tomales Bay and Tijuana Estuary. In our study we did find a potential hazard to human health. Fecal coliform concentrations in waters that border the park range from 340 MPN/100 mL – 24,000 MPN/100 mL. This level significantly exceeds Environmental Protection Agency recommendations of 300 MPN/100 mL for human contact with water. http://sf-rocks.sfsu.edu
ED41A-0082
Evaluation of Nonpoint Source Pollution in Stormwater Run-Off in Neighborhoods in San Francisco, California
This is the San Francisco Bay watershed encompasses 40% of California. When precipitation occurs, nonpoint source pollutants such as fertilizers, heavy metals, pesticides, gas and oil, enter the San Francisco Bay through this watershed. These pollutants contain dangerous chemicals that can potentially impact people and local ecology. The goal of Project Watershed is for high school students to design a study that investigates nonpoint source pollution in their own neighborhood and correlate these findings to the human activity in the neighborhood. Fifteen high school students participating in this study designed a stormwater collection devise that was installed in the public storm drain near each students home. Stormwater samples where collected from each device during the period of December 2006 to April 2007. Students assessed the samples for nitrates, heavy metals, oil and grease, total petroleum hydrocarbons, toluene and methyl tert-butyl ether (MTBE). This study outlines the methods students used to design the study and a summary of results found. http://sf-rocks.sfsu.edu
ED41A-0083
Air Quality Indicators at Lake Merritt, Oakland, California
Lake Merritt is significant in its role as both a recreational center for humans, as well as a refuge for migratory wild birds. It is, however, closely surrounded by streets and highways, and even sees a large amount of water traffic by motor-driven boats and pontoons. These two factors contribute to what we suspect is a generally high level of emissions in the atmosphere surrounding the lake. While the harmful components of these emissions can be measured directly using specialized and generally expensive tools, the goal of our research is to explore the use of tree leaves as indicators of air quality. Properties of atmospheric air directly affect the quality of leaves because of plants' reliance on photosynthesis. In brief, photosynthesis requires the input of sunlight, water, and carbon dioxide to produce oxygen and glucose. The gateways through which many of these inputs and outputs pass are essential to every leaf's survival and are called stomata. However, water is an exception; since its entry into the plant's vascular system is through the roots, water generally diffuses outward at stomatal openings rather than inward. Therefore, plants must strike a balance between gaining carbon dioxide and losing water, as well as risk exposure to toxic compounds in the air itself. Primarily, guard cells fulfill this purpose by closing over stomatal openings to conserve water. However, we also believe that over generations of leaves, the absolute number of stomata itself can change to reflect the surrounding environment. That is, increases in carbon dioxide must coincide with higher levels of toxic compounds, which force the number of stomata to decrease over time. Our research examined the relationship between quantitative presence of stomata for several species of trees and the levels of carbon dioxide, oxygen, and wind-speed for ten sites around Lake Merritt. Wind-speed is one of our primary measures because increasing wind velocity leads to water diffusing out of the leaves at a higher rate. Stomata were counted by plating a 0.5 cm2 square of the lower epidermal layer of leaves collected at each of the sites, then examining it through a microscope at 400X. Preliminary data suggests an unexpected direct relationship between carbon dioxide and stomata, although the correlation is not strong – itself suggesting that yet another factor exists. We suspect that wind-speed may be that very factor, though further analysis of our current body of data is required. Overall, the stomata count does indeed seem to reflect properties of the environment.
ED41A-0084
Noise Pollution and How it Can Indirectly Affect the Amounts of Particulate Matter in the Environment
Human and animal activity that occurs on gravel and dirt roads tends to contribute to high levels of particulate matter in the atmosphere. Birds molt their feathers, automobiles emit unused residues, and humans and animals stir up debris on the ground. Not only do these activities generate particulate matter, but they also generate noise. The aim of our study was to determine if a direct correlation exists between the amount of particulate matter and the noise levels in select areas within the Lake Merritt Park region of downtown Oakland, California. In addition, our research was aimed at determining if the level of noise at various locations conforms to City of Oakland regulations. Over a four-week period we measured noise levels and particulate matter concentrations at 27 different sites within the Park region. Preliminary results indicate that at a construction site and a residential area near the lake a direct correlation between our two variables existed; high noise level accompanied high particulate matter while low noise level accompanied low particulate matter, respectively. However, at the majority of the areas around the lake either indirect or no correlation was observed. Based on our results thus far, we conclude that noise levels are not indicative of particulate matter levels and that noise levels around Lake Merritt do conform to the city's regulations.
ED41A-0085
The Effects of Ozone, Particulate Matter, and Oxygen on the Air Quality at Oakland Technical High School, Oakland, California
Oakland has a reputation for being one of the most polluted cities in Northern California. Several causes for this include the presence of the Port of Oakland, the large amounts of industry associated with the Port, and the many freeways that weave their way through the city. There are many factors that influence the quality of air that students breathe at Oakland Technical High School (Oakland Tech). In conducting our study, we sought to determine the degree to which several key factors influence the air quality. This was accomplished by measuring the concentration of fine and course particulate matter, O2, and Ozone in air. This data was then used to create an air quality index based on U.S. EPA standards. Using this index we generated contour maps that were then used to determine the relative air quality in different areas of the school. Oakland Tech is located in North Oakland, and while North Oakland is not known as a severely polluted area, any air pollution that does exist would affect the student population on a daily basis. The likely sources of pollutants in air breathed by students are a freeway located nearby and the Port of Oakland, located approximately 5 kilometers south of the school. To help identify the sources of detected pollutants, we made wind direction measurements. As very little pollution is generated within the school or the surrounding residential areas, the majority is likely to be transported by wind. Preliminary results derived from these measurements suggest that air rarely moves the in northerly direction (from of the port toward Oakland Tech.), and never with enough speed to transport industrial pollution to the school. Based on these results, we believe that the most likely source of pollution encountered at Oakland Tech is the nearby freeway. This suggests that the predominant source of pollution is car exhaust.
ED41A-0086
Particulate Concentration Levels in Chinatown, Oakland, California
Chinatown is located near the center of the busy business district of downtown Oakland, California. It is one of the most inhabited and congested areas in the City of Oakland, averaging 4,000 vehicles and 3,000 pedestrians per hour at a key intersection in the center of the neighborhood. Particles produced by automobiles and construction can settle into the bronchi of lungs and induce asthma attacks, irritate cardiovascular tissue, and possibly lead to lung cancer and death. Particulate pollution is a serious problem that is estimated to cause between 20,000 and 50,000 deaths per year in the US alone. Hence, evaluation of the air quality of the Chinatown neighborhood is important, because it helps to address issues that are of great concern to residents of the area. The primary goal of our project was to measure particulate concentration levels at various intersections in Oakland's Chinatown to determine if the air quality met U.S. EPA standards, and to take note of any trends that may occur over a period of months. We were primarily concerned with particles that are 2.5 micrometers diameter and smaller, as smaller particles are easily inhaled and directly affect the respiratory system. We were interested in identifying any intersections that may have had significantly higher levels than other intersections. Using a map of Chinatown, we chose 12 intersections and made measurements at these points over the course of six months, beginning in February and ending in July of 2007. Particulate matter measurements were made using a FLUKE 893 Particle Counter. Measurements recorded on the first day of our study, February 4, 2007, which was the day of an annual street festival, yielded the highest values for particulate matter concentration in our dataset. This was followed by a significant drop in concentration the following week, and then a gradual increase of concentration as the months progressed. No one location yielded values significantly higher than any other, and, except for the first and last day (where there was experimental error), recorded values seem to meet EPA standards. We conclude that the high particulate matter levels we observed were due to heavy crowding and traffic jams near street corners during the time of the festival. We also conclude that particulate pollution levels in the Chinatown neighborhood are generally acceptable, except during festivities that generate heavy congestion. We intend conduct further investigations, particularly at next year's street festival, to confirm observations made thus far.