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2013

Analyzing the Madden-Julian Oscillation with next-generation atmospheric simulation technology

Student: Andrew Vande Guchte
Faculty Advisor: Mike Pritchard

The Madden-Julian Oscillation (MJO) is a poorly understood, poorly simulated, but very important planetary pattern of rainfall affecting billions of people in the tropics. Understanding the MJO has proved especially hard because it is difficult to simulate in most climate and weather prediction models. As a result the future climate sensitivity of the MJO is virtually unknown, which is a massive problem for tropical residents facing climate change adaptation. Fortunately as national supercomputer grids expand to unprecedented scales, prototype next generation atmospheric simulation technologies are coming online. This is enabling numerical investigation of explicit interactions supporting MJO physics for the first time. This project aims to apply the Superparameterized Community Atmosphere Model (SPCAM) – one of the only global models in the world that captures a realistic MJO signal – to address unsolved atmospheric physics mysteries such as “how do convection and large-scale winds couple to produce the Madden Julian Oscillation in the tropics?” and “why do most climate models struggle to capture the MJO?” Such work is in turn needed to help bring down the error bars on the broader question “how will tropical rainfall change in our future climate?” Depending on experience and ability, the work will range from MatLAB analysis of existing model output, to designing and managing new model simulations in a UNIX environment on national supercomputer grids.

Project Time Allocation: Computer Lab 100%

 

Biosphere-atmosphere trace gas exchange and aerosol emissions from Alaska

Students: Ashley Braunthal, Nicolas Cuozzo
Faculty Advisor: Claudia Czimczik, Jim Randerson

As perennial sea ice cover continues to decline, boreal and arctic ecosystems are simultaneously being exposed to the most rapid rise in surface air temperatures, increases in both the frequency and intensity of precipitation, permafrost degradation, increasing growing season length, and changes in fire regime.  The consequences of these changes on the carbon balance of northern ecosystems are not known with confidence, since fundamental elements of the complex biological-climatologic-hydrologic system are poorly quantified.  As part of the larger science initiative "Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE)“, we will quantify trace gas exchange and aerosol emissions from ecosystems in Alaska.

2 students will be admitted for this project

Successful applicants will:

Measure trace gas concentrations (e.g. CO2 and CH4) in background air and emissions from vegetation fires using a state-of-the-art cavity-ring down laser spectrometer,

Learn to analyze high-frequency trace gas datasets and create time-series and, or maps,

Collect particulate matter using high-volume samplers that will be used to quantify and characterize particulate emissions from AK ecosystems and vegetation fires,

Produce and present a poster summarizing their activities and results at UC Irvine.

This project involves about 6 weeks of fieldwork in Alaska as part of a small group. We will be camping or staying at simple lodges. Encounters with wildlife (e.g. mosquitos, moose, bears) are very likely.  We are looking for students that enjoy the outdoors and, or have backcountry experience.  Students need to be reliable team players, physically fit and hold a valid driving license and ID for air travel.  Experience with data analysis software (e.g. excel, matlab) is not required, but advantageous.

 

Global atmospheric composition and chemistry - model simulations for the IPCC 2013 Assessment

Student: Nicole DeLuca
Faculty Advisor: Michael Prather

Analyze climate model simulations from the IPCC Archive (CIMP5) and the UCI chemistry-transport model to identify and characterize the change in extreme pollution episodes over the 21st century.

Student will work with Matlab and Fortran to read adn analyze the data set.

Project time allocation: Computer lab = 100%

 

 

 

 

 

Greenhouse gas measurements in the LA Basin

Student: Valerie Carranza
Faculty Advisor: Jim Randerson

Regulation of anthropogenic greenhouse gases requires new measurements to verify reported emissions.  For example, recent measurements of methane concentrations in the Los Angeles basin suggest that emissions are up to 40% greater than what is currently accounted for by the California Air Resource Board inventory. Much of the reported emissions occur in urban areas, yet detailed greenhouse gas concentration profiles in the vicinity of these sources are not well known.  We seek to improve understanding of the spatial and temporal patterns of emissions by using a mobile laboratory to measure the distribution of greenhouse gases with known urban sources (CO2, CH4)  in the Los Angeles basin.

We are looking for a student to assist with these measurements, and to develop a project based on the data collected by the mobile laboratory. For example, the student may chose to focus on a specific emission sector, such as landfills, and will combine new measurements and available data to improve basic understanding of the emission source, with the goal of application of this knowledge to future monitoring or mitigation efforts.

This work involves time spent in the field (driving around emissions sources and various landscapes in the LA basin), and analysis time spent at a computer.  The student will learn to collect data with a mobile laboratory equipped with cavity-ring down spectrometers measuring concentrations of CO2, CH4, CO, H2O, O3; analyze high-frequency, spatially-resolved datasets; and to communicate his/her findings though a poster summarizing the results of the research. Experience with ArcGIS and/or data analysis software (such as Matlab) and a valid driver's license are preferred but not required.

 

Quantifying Diurnal and Seasonal Wind Power at Crystal Cove

Student: Andrew Miller
Faculty Advisor: Charlie Zender

Wind power is a largely untapped renewable energy resource which can alleviate both baseline and peak energy demand in California. Most demand comes from coastal population centers therefore quantifying availability of coastal and near-offshore wind power availability is crucial to informing future zoning and power-grid decisions. Coastal wind power potential in Orange County is weak to moderate, yet the contribution of the diurnal sea-breezes to this power has not been quantified. UCI operates a meteorology station at nearby Crystal Cove State Park (CCSP) which has recorded years of coastal weather. This project will analyze those observations to characterize the seasonal and diurnal components of CCSP weather and wind power. Project outcomes will 1) help place OC coastal resources in the context of the broader regional and state-wide renewable resources; 2) document the microclimate of this undeveloped slice of the Southern California coast; and 3) improve educational resources at CCSP.

Project Time Allocation: Computer lab = 90%, On-site observations = 10%

 

 

 

Soil microbial responses to climate change in ecosystems around the globe


Student: Melissa Curran
Faculty Advisor: Steve Allison

Micro-organisms such as bacteria and fungi play a critical role in global cycles of carbon and nutrients. Warming and other changes in climate are likely to affect these cycles through impacts on microbial communities. Despite this relevance for climate feedbacks, the response of microbial processes to climate change is still poorly quantified. Therefore, the goal of this project is to determine how microbes respond to changes in temperature, and whether they can adapt to a warming climate. Students will learn how to conduct biochemical assays of microbial enzyme activities, determine microbial carbon use efficiency, and measure microbial biomass and respiration. These parameters will be assessed in soils from six sites around the world with climate warming manipulations. By examining the response of microbial communities to temperature change, we aim to predict how microbial function and ecosystem processes will differ in a warmer climate. The data collected will be used to develop better coupled models of the carbon-climate system. 

Project time allocation: Laboratory: 70%, Computer analysis: 20%, Fieldwork: 10%

 

 

 

Trace gases in polar ice cores

Student: Isis Frausto-Vicencio
Faculty Advisor: Eric Saltzman

The gases trapped in polar ice cores are a remarkable archive for investigating the chemical changes in our atmosphere. Most of the research to date has been on greenhouse gases (CO2, CH4, N2O), but there are a wide range of other gases present in the atmosphere including hydrocarbons, halocarbons, sulfur gases, and nitrogen gases which have not been studied. These ice archive of these trace gases may contain a wealth of information about biogeochemical cycles, atmospheric chemistry, and the impact of man's activities on the atmosphere.

This project will involve making measurements of trace gases in Antarctic ice cores to assess whether the ice archive does accurately record the composition of the ancient atmosphere, and to examine variations over the past few thousand years. The research experience will involve learning how to extract gases from air bubbles in ice, and how to analyze the chemical composition of the extracted air using a gas chromatograph/mass spectrometer.

Project Time Allocation: Computer Lab: 20%, Chemistry Lab: 80%

 

2012

Global atmospheric composition and chemistry - model simulations for the IPCC 2012 Assessment

Student: Ayush Jangam
Faculty Advisor: Michael Prather

Analyze climate model simu.ations from the IPCC Archive (CIMP5) and the UCI chemistry-transport model to identify and characterize the change in extreme pollution episodes over the 21st century.

Student will work with Matlab and Fortran to read adn analyze the data set.

Project time allocation: Computer lab = 100%

 

 

 

 

 

How do seasonal resolution geochemical variations preserved in speleothems from Laos reflect past Asian monsoon variability?
Student: Julianna McDonnell

Faculty Advisor: Kathleen Johnson

In order to most accurately identify the causes and mechanisms of climatic change, it is necessary for us to develop high-resolution paleoclimate records which tell us about past climate changes on seasonal, annual, and decadal timescales.  Calcite speleothems are well suited for paleoclimate reconstruction because they are normally pure calcite, are well-preserved, can be precisely dated using Uranium-series methods, and contain multiple types of paleoclimate proxy data in their highly resolvable growth bands.  In particular, measurements of δ18O along speleothem growth axes are often used to reconstruct past rainfall δ18O, which is related to temperature and/or rainfall amount.  Additional information can be gained from other geochemical proxies, such as δ13C and trace element composition, and from physical proxies, such as annual layer thickness and crystal morphology.   

This project will involve seasonal resolution measurements of oxygen and carbon isotope and trace element composition in samples micromilled along the growth axis of a speleothem from Laos to investigate past seasonality of the Asian monsoon system.  Analysis of modern rainfall δ18O data from the Global Network for Isotopes in Precipitation in conjunction with instrumental climate data will be utilized to help interpret the speleothem record in terms of past rainfall and/or temperature.  In addition, digital image analysis of speleothem growth bands will allow investigation of the timing of visible laminations and will be used to generate an age model, in combination with radiometric U-Th dates.  The research experience will include the use of a computer controlled micromilling system, microscopes and digital image analysis software, microbalances, a stable isotope mass spectrometer, and an ICP-MS. 

Project Time Allocation: 

Sample Prep./Microscope Lab:  50%
Chemistry Lab = 50%

 


Quantifying Diurnal and Seasonal Wind Power at Crystal Cove

Student: Michelle Serino
Faculty Advisor: Charlie Zender

Wind power is a largely untapped renewable energy resource which can alleviate both baseline and peak energy demand in California. Most demand comes from coastal population centers therefore quantifying availability of coastal and near-offshore wind power availability is crucial to informing future zoning and power-grid decisions. Coastal wind power potential in Orange County is weak to moderate, yet the contribution of the diurnal sea-breezes to this power has not been quantified. UCI operates a meteorology station at nearby Crystal Cove State Park which has recorded about 1 year of coastal weather. This project will analyze the observations to quantify the seasonal and diurnal components of OC coastal wind power resources. The results will be used to evaluate and calibrate the accuracy of mesoscale weather models in OC. Project outcomes will 1) help place OC coastal resources in the context of the broader regional and state-wide renewable resources; 2) document the microclimate of CCSP to complement other ongoing marine and ecological characterizations of this undeveloped slice of the Southern California coast.

Project Time Allocation

Computer lab = 90%
On-site instrument calibration = 10%

 

Reconnaissance-level projection of ice sheet outlets

Student: Katherine Shover
Faculty Advisor: Todd Dupont

The potential for ice-sheet volume change to lead to significant sea-level change is of considerable scientific and societal interest. Unfortunately there is also considerable uncertainty on this issue, with respect to both measurements of the present-day and recent contributions, and modeled near-term projections.

This project is aimed at addressing this uncertainty through regional ice-sheet modeling under the umbrella of a larger project referred to as seaRISE (see http://websrv.cs.umt.edu/isis/index.php/SeaRISE_White_Paper). By using reduced dimensional numerical models of ice flow and mass balance we will provide estimates for the near-term trajectory of various important outlets such as Jakobshavn, Upernavik, Pine Island, and Thwaites. Prospective students should be familiar with calculus and have some familiarity with one or more programming languages.

Project Time Allocations: Computer Lab/White Board: 100%

 

 

Remote sensing of groundwater depletion using GRACE

Student: Amabella Lambinicio
Faculty Advisor: Jay Famiglietti

Groundwater depletion occurs when withdrawals, for example for drinking water and for irrigation, exceed replenishment, for example, from rainfall. Many of the world's major aquifer systems, in particular, those that do not receive much precipitation, are being rapidly depleted (for example, California's Central Valley, and the High Plains aquifer of the midwest) but at rates that are difficult to quantify using traditional methods. Our group has pioneered the use of a new satellite gravity mission, called GRACE (Gravity Recovery and Climate Experiment) to monitor groundwater storage changes, in many cases, that could not otherwise be quantified. We are seeking an REU student to work with our team to focus on a specific aquifer (to be selected from the Southeastern U.S., Southern Europe, China, Northern Africa, or the Tibetan Plateau) and to characterize current rates of groundwater depletion in that region. Work will involve assembling existing available datasets and performing analyses on these data.  The selected student will have strong support from our research group in all aspects of the work. The research conducted will complement our current and existing work on groundwater depletion the U.S., the Middle East, India, and Australia, and is already having important implications for national and international water resources management.

 

Soil microbial responses to climate change in ecosystems around the globe

Student:  Stephanie Beasley
Faculty Advisor: Steve Allison

Micro-organisms such as bacteria and fungi play a critical role in global cycles of carbon and nutrients. Warming and other changes in climate are likely to affect these cycles through impacts on microbial communities. Despite this relevance for climate feedbacks, the response of microbial processes to climate change is still poorly quantified. Therefore, the goal of this project is to determine how microbes respond to changes in temperature, and whether they can adapt to a warming climate. Students will learn how to conduct biochemical assays of microbial enzyme activities, determine microbial carbon use efficiency, and measure microbial biomass and respiration. These parameters will be assessed in soils from six sites around the world with climate warming manipulations. By examining the response of microbial communities to temperature change, we aim to predict how microbial function and ecosystem processes will differ in a warmer climate. The data collected will be used to develop better coupled models of the carbon-climate system. 

Project time allocation:

Laboratory: 70%
Computer analysis: 20%
Fieldwork: 10%

 

Trace gases in polar ice cores

Student: Melinda Nicewonger
Faculty Advisor: Eric Saltzman

The gases trapped in polar ice cores are a remarkable archive for investigating the chemical changes in our atmosphere. Most of the research to date has been on greenhouse gases (CO2, CH4, N2O), but there are a wide range of other gases present in the atmosphere including hydrocarbons, halocarbons, sulfur gases, and nitrogen gases which have not been studied. These ice archive of these trace gases may contain a wealth of information about biogeochemical cycles, atmospheric chemistry, and the impact of man's activities on the atmosphere.

This project will involve making measurements of trace gases in Antarctic ice cores to assess whether the ice archive does accurately record the composition of the ancient atmosphere, and to examine variations over the past few thousand years. The research experience will involve learning how to extract gases from air bubbles in ice, and how to analyze the chemical composition of the extracted air using a gas chromatograph/mass spectrometer.

Project Time Allocation:

Computer Lab: 20%
Chemistry Lab: 80%

 

Understanding the sources of air pollution in the Los Angeles basin using 14C measurements

Student: John Kearney
Faculty Advisor: Claudia Czimczik, Jim Randerson, G.M. Santos

Aerosols in the Earth’s atmosphere influence the global climate and adversely impact human health. Aerosols contain a range of inorganic compounds that are mostly well attributed to their sources, e.g. Cu & Zn are emitted during industrial processes, while Mg and Si originate from soil erosion. In contrast, the sources of carbonaceous (carbon containing) aerosols are still poorly understood because they consist of a wide variety of compounds, which are extremely difficult to individually attribute to their sources. Therefore, carbonaceous aerosols are subdivided into two main groups: organic carbon (OC; light-weight organic molecules) and black carbon (BC; mostly soot), which are fundamentally different in many physical and chemical aspects.

To assess sources of both OC and BC, radiocarbon analysis is the method of choice. Usually applied in dating archeological artifacts, radiocarbon measurements can also be used to determine the origin of carbon in aerosols. In particular, we can distinguish carbonaceous aerosols produced in various combustion processes: traces of radiocarbon are found in all living things including plants. When those plants are burned (e.g. in forest fires) the carbon atoms in the produced aerosols will comprise a natural amount of 14C (half-life: 5,730 years). In contrast, traffic emissions stem from fossil fuels, which were formed millions of years ago and thus no longer contain radiocarbon due to complete radioactive decay. At UC Irvine, radiocarbon measurements are carried out with a technique called accelerator mass spectrometry (AMS). The goal of this project is to analyze a set of aerosol samples from the Los Angeles basin for their OC:BC-ratio and the radiocarbon content of each aerosol group. Results will allow us to calculate the influence of plant-derived versus traffic/industry aerosol emissions. The successful applicant will acquire and apply their knowledge on:

OC/BC separations with the widely used Sunset aerosol analyzer
Working with cryotraps and flame sealing
Clean working, handling of microgram level samples
Preparation of samples for AMS measurements
AMS instrument, measurement and data analysis
Comparison of observations with atmospheric model estimates of aerosols
Data interpretation and scientific writing
Project Time Allocation:

Lab: 70%
Computer Lab: 30%

 

2011

Can trace element ratios in Olivella biplicata shells from California be used to reconstruct paleoclimate?

Student: Jonathan Nye
Faculty Advisor: Kathleen Johnson

Seasonality is a fundamental aspect of climate at mid-to-high latitudes but finding records of past climate with seasonal-resolution is difficult outside of the tropics. This limits our understanding of the role of seasonality in controlling mean climate and our ability to model this aspect of climate. Recently marine mollusk shells have shown great potential to act as archives of seasonal-resolution climate. By analyzing the stable isotope and trace element composition of successive samples along the cross-section of a shell then the history of seawater temperatures and salinity experienced by the mollusk over its lifetime can be reconstructed.

Olivella biplicata shells are very commonly found (likely over 1 million in total) in archaeological sites around the western US as they were used as a form of currency. The oxygen isotope composition of these shells has been shown to faithfully record the seasonal sea surface temperature (SST) range (Eerkens et al 2005, 2007, 2010). However there have been no high-resolution studies to investigate whether trace element ratios such as Mg/Ca or Sr/Ca within the shells also record environmental information or are more strongly influenced by biological factors such as growth rates. This project aims to investigate the relationships between instrumental oceanographic records, such as seawater temperature and salinity, and the trace element profiles of modern Olivella biplicata shells. If clear relationships can be determined then this would be a great step forward in developing archaeological marine mollusk shells as archives of paleoclimate information in California and further north. The data generated by this study may also be of assistance to archaeologists investigating former trade routes of American Indian communities in the region.   

The project will involve micromilling of modern and archaeological marine mollusk shells and stable isotope and trace element analysis. Students would gain experience in micromilling, microbalances, and stable isotope and trace element mass spectrometry.

Project Time Allocation: Sample Prep./Microscope Lab = 50%, Chemistry Lab = 50%

 

Carbon cycling in soils at the top of the world

Student: Jordan Samuel Thomas
Faculty Advisor: Claudia Czimczik

Arctic tundra soils store vast amounts of organic carbon. Understanding how rapidly this pool can be mineralized as a consequence of warming air temperatures and changes in the timing and magnitude of precipitation events is a major uncertainty in predicting future levels of carbon dioxide in the atmosphere.

Winter snow depth has recently been identified as a major control of growing season length, permafrost, soil nitrogen mineralization rates, and winter CO2 emissions – all in turn effecting annual ecosystem carbon budgets and plant cover and community composition. Currently, our understanding of carbon cycling in the Arctic is based primarily on studies in the low Arctic of Alaska and Scandinavia.

The goal of this project is to investigate the timing and magnitude of carbon dioxide emissions from high arctic soils as a function of snow depth. After some initial training at UC Irvine, students will join our research team in northwest Greenland for about one month, followed by data assimilation at UC Irvine.

In Greenland, measurements will be made from soil surface chambers and wells at different depth in the soil using a portable infrared gas analyzer at two experiments where snow depth has been manipulated above ambient levels. In addition, students will learn about the monitoring of other greenhouse gases (methane, nitrous oxide) and dissolved organic carbon in rivers - as we expect active participation in all ongoing research efforts of our field team.

At UC Irvine, students will be introduced to the analysis of carbon isotopes with accelerator mass spectrometry as a measure to study the cycling of carbon in terrestrial ecosystems.

Note. Since the fieldwork component of this project is in a remote location, students need to be physically fit, hold a valid passport, and participation is subject to a background security check.

 

Global atmospheric composition and chemistry - model simulations for the IPCC 2012 Assessment

Student: Kristina LaBoy
Faculty Advisor: Michael Prather

For the 2001 IPCC, a number of international research groups using global atmospheric chemistry models worked together to turn the projected emissions scenarios for the 21st century into an agreed-upon best answer for the projected atmospheric composition. In addition to forcing the climate, future atmospheric composition influences air quality globally as well as agricultural and natural ecosystems (e.g., Prather et al., Fresh air in the 21st century?, Geophys. Res. Lett. 30:1100, 2003, see figure). For the 2012 IPCC 5th Assessment Report, a new set of emissions scenarios called Representative Concentration Pathways (RCPs) have been developed and a similar effort to assess future atmospheric composition is needed. At UC Irvine we will be running these 21st century simulations with our chemistry-transport model. The first work will use current meteorology and later we will need to run with meteorology for a future climate. This project will involve analyzing the calculations of future composition and chemistry and working with the chemistry-transport model to examine sensitivities to key uncertainties and hence place error bars on the modeled projections.

Project time allocation: Computer lab = 100%

 

Microbial response to environmental change in the southern California coastal ocean

Student: Nick Kelley
Faculty Advisor: Adam Martiny

Human activities in coastal regions are linked to harmful algae blooms (HABs), pathogenic bacteria, hypoxia and declining fisheries. Ocean microbial communities both control and respond to these ecosystem changes because microbes grow rapidly and dominate marine primary production, respiration and nutrient cycling. The main goal of this project is to link water quality with microbial function and community dynamics. The research includes sampling seawater several times a week from Newport Pier and analyzing nutrient concentrations and microbial community composition using genetics tools (e.g. PCR). You will be working in a team with other students. Some lab experience is necessary for this project.

Project Time Allocation: Lab = 50%, Fieldwork = 50%

 

 

Reconnaissance-level projection of ice sheet outlets

Student: Madeleine Campbell
Faculty Advisor: Todd Dupont

The potential for ice-sheet volume change to lead to significant sea-level change is of considerable scientific and societal interest. Unfortunately there is also considerable uncertainty on this issue, with respect to both measurements of the present-day and recent contributions, and modeled near-term projections.

This project is aimed at addressing this uncertainty through regional ice-sheet modeling under the umbrella of a larger project referred to as seaRISE (see http://websrv.cs.umt.edu/isis/index.php/SeaRISE_White_Paper). By using
reduced dimensional numerical models of ice flow and mass balance we will
provide estimates for the near-term trajectory of various important outlets such as Jakobshavn, Upernavik, Pine Island, and Thwaites. Prospective students should be familiar with calculus and have some familiarity with one or more programming languages.

Project Time Allocations: Computer Lab/White Board: 100%

 

Remote sensing, ocean biogeochemistry, and marine primary productivity

Student: Matthew Ware
Faculty Advisor: Keith Moore

Observational datasets relevant for studying marine phytoplankton productivity and biogeochemical cycling in the oceans have expanded greatly in the past decade. New global syntheses of ship-based observations at the global scale provide information on nutrient distributions, carbon chemistry, and phytoplankton community structure. Simultaneously the number of satellite remote sensing observations has also greatly expanded with improved accuracy. Remote sensing observations provide estimates of surface chlorophyll concentrations (phytoplankton biomass), phytoplankton carbon concentrations, and primary production. Satellites also provide a number of observations of physical oceanographic variables such as sea surface temperature, surface salinity, and wind speed and direction over the oceans. In this project the student will analyze some of these datasets to study the controls on primary production, phytoplankton community composition, and the biogeochemical cycling of key elements (i.e. carbon, nitrogen, phosphorus). A better understanding of these factors will allow us to better predict how the oceans will respond to the ongoing climate change.

Response and adaptation of microbial processes to climate change

Student: Charlotte Alster
Faculty Advisor: Steve Allison

Micro-organisms such as bacteria and fungi play a critical role in global cycles of carbon and nutrients. Warming and other changes in climate are likely to affect these cycles through impacts on microbial communities. Despite this relevance for climate feedbacks, the response of microbial processes to climate change is still poorly quantified. Therefore, the goal of this project is to determine how microbes respond to changes in temperature, and whether they can adapt to a warming climate. Students will learn how to conduct biochemical assays of microbial enzyme activities, determine microbial carbon use efficiency, and measure microbial biomass and respiration. These parameters will be assessed in soil and/or seawater samples from different temperature regimes, such as latitudinal gradients and warming manipulations. By examining the response of microbial communities to temperature change, we aim to predict how microbial function and ecosystem processes will differ in a warmer climate.

Project time allocation: 70% laboratory, 20% computer analysis, 10% fieldwork.

 

 

 

Response of ocean bacteria to global climate change

Student: Allison Moreno
Faculty Advisor: Adam Martiny

The temperature of ocean surface waters may increase due to climate change. This may trigger a cascade of events that leads to deplete nutrient supplies in large parts of the ocean. As a result, small phytoplankton like marine cyanobacteria Prochlorococcus and Synechococcus may thrive and outcompete larger cells due to a larger cell-surface to -volume ratio. This may reduce the amount of carbon sinking towards the seafloor and thereby have a significant impact on the global carbon cycle.

In this project, the student will first identify a quantitative relationship between existing environmental variation (e.g. temperature and nutrients) and the distribution of ocean microbial phytoplankton. This will involve analyzing a recently compiled comprehensive database containing all known observations of these bacteria and remote sensing data. The student can then use this empirical model to predict future distributions of phytoplankton under various climate change scenarios. Some data analysis or programming experience is necessary for this project.

Project Time Allocation: Computer Lab = 100%

 

 

 

Trace gases in polar ice cores

Student: Elizabeth Fosse
Faculty Advisor: Eric Saltzman

The gases trapped in polar ice cores are a remarkable archive for investigating the chemical changes in our atmosphere. Most of the research to date has been on greenhouse gases (CO2, CH4, N2O), but there are a wide range of other gases present in the atmosphere including hydrocarbons, halocarbons, sulfur gases, and nitrogen gases which have not been studied. These ice archive of these trace gases may contain a wealth of information about biogeochemical cycles, atmospheric chemistry, and the impact of man's activities on the atmosphere.

This project will involve making measurements of trace gases in Antarctic ice cores to assess whether the ice archive does accurately record the composition of the ancient atmosphere, and to examine variations over the past few thousand years. The research experience will involve learning how to extract gases from air bubbles in ice, and how to analyze the chemical composition of the extracted air using a gas chromatograph/mass spectrometer.

Project Time Allocation: Computer Lab = 20%, Chemistry Lab = 80%

 

2009

A record of methyl chloride from five Antarctic ice cores

Student:  Kaitlin Schrote
Faculty Advisor: Eric Saltzman

The gases trapped in polar ice cores are a remarkable archive for investigating the chemical changes in our atmosphere. Most of the research to date has been on greenhouse gases (CO2, CH4, N2O), but there are a wide range of other gases present in the atmosphere including hydrocarbons, halocarbons, sulfur gases, and nitrogen gases which have not been studied. These ice archive of these trace gases may contain a wealth of information about biogeochemical cycles, atmospheric chemistry, and the impact of man's activities on the atmosphere. 

This project will involve making measurements of trace gases in Antarctic ice cores to assess whether the ice archive does accurately record the composition of the ancient atmosphere, and to examine variations over the past few thousand years. The research experience will involve learning how to extract gases from air bubbles in ice, and how to analyze the chemical composition of the extracted air using a gas chromatograph/mass spectrometer. (Project Time Allocations: Computer Lab = 20%, Chemistry Lab = 80%, Fieldwork = 0%)

 

Carbon degrading enzymes: Basic kinetics and responses to temperature

Student: Madeleine Stone
Faculty Advisor: Steve Allison

Microorganisms are incredibly diverse and play important roles in the global cycling of carbon and nutrients. In particular, microbes determine how much carbon is sequestered in soils and sediments versus mineralized back to carbon dioxide. Since carbon and nutrients are usually present in complex chemical structures, we know that certain microbes must produce extracellular enzymes to cycle these elements. However, we still know very little about the particular microbes that regulate carbon balance, or the factors that control their activity. 

The goal of this project is to examine the frequencies of enzyme-producing microbes versus competitor microbes in soils and marine environments. The prediction is that enzyme producers should be relatively more common in low diffusion environments, such as soils and sediments. In high diffusion environments, such as ocean water, enzyme producers should lose out in competition with microbes that acquire carbon and nutrients directly. The research will involve collecting and culturing microbes from different environments and analyzing their identity and function. Students will learn how to set up microbial cultures, extract and sequence DNA, and conduct assays of extracellular enzyme activity. Project time allocation: 70% laboratory, 20% computer analysis, 10% fieldwork

 

Developing a global groundwater scarcity index

Student: Kate Voss
Faculty Advisor: Jay Famiglietti

The combined influences of global change and population growth are applying significant stress to available water resources in many parts of the United States and the world. Climate change is already resulting in redistribution of precipitation, as well as changes in the timing, intensity and frequency of storms. Many parts of the world are also currently experiencing increasing drought frequency (in the mid-latitudes for example) while others (the tropics and high latitudes) are experiencing increases in precipitation. These changes in rainfall patterns must be coupled with the demographics of population growth and migration for a full assessment of the stresses on available water resources in the future. 

The goal of this project will be to conduct a new assessment of future stresses to water availability driven by these two factors. In particular, a new index of expected water stress will be developed that accounts for a) surface and groundwater resources; b) remote sensing data and global climate model results that shows how these have been changing; and c) global population growth. The resulting index can be used to produce a global map of regions that may have limited water availability due to population growth, climate change or both.

 

Enzyme activity in coastal marine waters: response to temperature and metal ion availability

Student: Jane Wiedenbeck
Faculty Advisor: Adam Martiny

The temperature of ocean surface waters may increase due to climate change. This may trigger a cascade of events that leads to deplete nutrient supplies in large parts of the ocean. As a result, small phytoplankton like marine cyanobacteria Prochlorococcus and Synechococcus may thrive and outcompete larger cells due to a larger cell-surface to -volume ratio. This may reduce the amount of carbon sinking towards the seafloor and thereby have a significant impact on the global carbon cycle. 

In this project, the student will first identify a quantitative relationship between existing environmental variation (e.g. temperature and nutrients) and the distribution of ocean microbial phytoplankton. This will involve analyzing a recently compiled comprehensive database containing all known observations of these bacteria and remote sensing data. The student can then use this empirical model to predict future distributions of phytoplankton under various climate change scenarios. Some data analysis or programming experience is necessary for this project. (Project Time Allocations: Computer Lab = 100%, Lab = 0%, Fieldwork = 0%)

 

Examining total water storage in the Central Valley river basins

Student: James Bethune
Faculty Advisor: Jay Famiglietti

 

Relationship between fracture mechanics and heat transfer in Moulin formation
Student: Nathaniel Chaney

The flow and distribution of subglacial water is critical to lubricating the flow of ice above it, and thereby influences ice dynamics more generally. Interest in the dynamics of ice sheets derives in part from their potential to contribute to large, and possibly rapid, variations in sea-level rise. Observations over the last decade have provided strong evidence for highly dynamic subglacial hydrology under some of the largest outlets of the major ice sheet. This includes the inferred movement of subglacial water pockets over large horizontal distances under large thicknesses of ice. At the same time it has become clear that there a vast array of at least quasi-stable water pockets, or lakes, under these ice sheets. 

What leads to stable versus transient water pockets? What might cause an initially stable water pocket to move? What are the important feedbacks between subglacial water flow and ice flow? These are some of the fundamental questions we will address as part of an ongoing research effort using analytic and numerical model experiments. Prospective students should be familiar with calculus and have some experience with programming. (Project Time Allocations: Computer Lab/White Board: 100%, Chemistry Lab 0%, Field Work 0%)

 

Seasonal Resolution Paleoclimate Records from Modern Mollusk Shells

Student: Laura Meyer
Faculty Advisor: Kathleen Johnson 

Seasonal-resolution paleoclimate records would allow the investigation of the role of seasonality in controlling mean climate and of the natural variability in climate patterns such as El Nino. Seasonal resolution climate archives are scarce, however, especially outside the range of tropical surface corals. Recently marine mollusk shells have been shown to preserve seasonal-resolution climate variations within their growth bands. The isotopic and chemical composition of a marine mollusk shell is related to the seawater temperature and salinity at the time it forms. Therefore, by analysing the stable isotope and trace element composition of successive samples along the cross-section of a shell, seawater temperatures and salinity experienced by the mollusk over its lifetime can be reconstructed. This can be demonstrated in modern mollusc shells from the California coastline by comparing the results with instrumental records. Fossil shells can then be analysed to provide some of the first seasonal-resolution paleoclimate records from California. Due to sea-level changes, however, fossil intertidal shells can be difficult to find in the field. Fortunately, though, over the last 10,000 years or more, humans have collected mollusks for food and there are many shells available from archaeological sites along the California coastline and on the Channel Islands. 

This project will involve microsampling of modern and archaeological marine mollusk shells and stable isotope and trace element analysis by mass spectrometry techniques to produce seasonal-resolution sea surface temperature and/or salinity records for California. The shells will also need to be radiocarbon dated to provide an accurate age. Students would gain experience in computer controlled micromilling, microbalances, stable isotope mass spectrometry, analytical chemistry, ICP-MS, and radiocarbon sample preparation. (Project Time Allocations: Sample Prep./Microscope Lab = 50%, Chemistry/Mass Spectrometry Lab = 50%).

 

The Effect of river plume nutrient input on ocean chlorophyll levels

Student: Gina Graziano
Faculty Advisor: Keith Moore

The flux of nutrients from the continents to the oceans is rapidly increasing due to anthropogenic nutrient loading to rivers from industrial and agricultural sources. These nutrient inputs can lead to large phytoplankton blooms and oxygen depletion in coastal waters, and perhaps to increased blooms of toxic algae that can resulting fish death and harm to humans as well. The riverine source is also key for the marine biogeochemical cycles of carbon, nitrogen and phosphorus and influences ocean productivity and climate over long timescales. 

In this project the student will help develop the framework for a global-scale modeling effort integrating the nutrient flux from rivers to an existing ocean ecosystem and biogeochemical model. The student will help develop parameterizations for nutrient loss within estuaries and coastal regions, between the river mouth and open ocean, and study the impact of riverine nutrients on marine ecology and biogeochemistry. A prior computer programming class is preferable, but not required for this project. (Project time allocations: Computer lab = 100%, Chemistry lab = 0%, Fieldwork = 0%).

 

2008

Project Faculty Advisor(s) Student
Microbial Enzyme Activities Vary Between Stream Microenvironments in Southern California Streams Steve Allison Rosemary Records
Inverting for Ice Stream Basal Friction Using Control Methods Todd Dupont Katie Davis
Short-term variation in marine microbial communities Adam Martiny Jackie Cannata
Phytoplankton Bloom Dynamics in the Region of South Georgia Island, Southern Ocean Keith Moore Jack Porter
Using Satellite Observations of Nitrous Oxide to Constrain the rate of Stratospheric Turnover and Mixing Michael Prather / Jessica Neu Josh Cossuth
Variations in atmospheric hydrocarbons in Greenland air Eric Saltzman Catherine Cassou
Carbon storage and net global warming potential of turfgrass Susan Trumbore Melissa Benitez
Nitrous oxide fluxes from urban turfgrass Susan Trumbore / Diane Pataki Matthew Ampleman

 

 

 

 

 

 

 

 

2007

Project Faculty Advisor(s) Student
Understanding Water Storage Changes in the Sacramento, San Joaquin, and Colorado River Basins Jay Famiglietti Karli Anderson
Global distribution of the marine cyanobacteria Prochlorococcus and Synechococcus Adam Martiny Melissa Chrisman
Phytoplankton Bloom Dynamics near the Kerguelen Plateau, Southern Ocean Keith Moore Vrinda Manglik
Water use of native and non-native plants in southern California urban landscapes Diane Pataki Justine Law
Scales of Horizontal Variability in Temperature, Water Vapor and  Ozone in the Upper Troposphere Michael Prather Katherine Marshall
Maximum-Entropy Method for Estimating Ocean Mixing Francois Primeau Jack Scheff
Methyl chloride in a deep Antarctic ice core Eric Saltzman Kristal Verhulst

 

 

 

 

 

 

 

 

2006

Project Faculty Advisor(s) Student
Water Storage Variability using the GRACE Satellite Mission Data Jay Famiglietti Lindsey McKenna
Dissolved iron distributions in the world ocean Keith Moore Olivia Braucher
Chlorophyll Distributions in the Arctic Ocean Keith Moore Johnathan Finley
A maximum entropy approach to water mass analysis Francois Primeau Scott Kibler
Methyl bromide in firn air Eric Saltzman Megan Bradley
Competition Between Soil Fungi and Bacteria: Does It Pay to Cheat? Kathleen Treseder Joseph Hoover
Effect of nitrogen addition on organic matter turnover in litter and soil from the San Bernardino Mountains, California Susan Trumbore Gloria Jiminez
El Niño-Monsoon Interactions Jin-Yi Yu Matthew Janiga