About Mike Devirian:
Michael Devirian’s career in the space program is the quintessential picture of a success. Since graduating from UC Riverside in 1966 with a degree in physics, Mike worked for the majority of his career at the Jet Propulsion Laboratory in Pasadena, California, where he served in various positions in space flight operations, including Director of Flight Operations on the Voyager Project; science data networking, science payloads on the International Space Station; the Hubble repair mission; and as program manager for space science instrument projects built and managed at JPL. From 2005-2012, he was the manager of NASA's Exoplanet Exploration Program, and its predecessor Navigator Program. He is a recipient of NASA’s Medal for Outstanding Leadership, and NASA’s Medal for Exceptional Service. Today he works as a consultant and is interested, among other things, in the environment, science, and technology. UCR’s EDGE Institute couldn’t be happier that Michael supports a scholarship fund for graduate students researching various aspects of global change.
Devirian Graduate Student Research Award:
On behalf of Mike Devirian, the UC Riverside EDGE Institute (Environmental Dynamics & Geo- Ecology) will support graduate students studying in areas related to global climate and environmental change and the associated changes to ecosystems. We will be awarded three $800 scholarships in 2017 and 2018. The scholarships can support any aspect of the student’s research, including fieldwork, conference attendance, or laboratory/computational expenses. Eligible applicants must be enrolled as full time graduate students at UC Riverside studying in the fields of biological, chemical, or physical sciences.
2018 Award Recipients
Valerie Carranza, Ph.D. Candidate in Environmental Sciences:
Remote sensing, mobile, and isotopic measurements of methane emissions and nitrous oxide from dairy manure management in the Central Valley of California
Dairy farming accounts for a substantial amount of methane (CH4) and nitrous oxide (N2O) emissions in the state of California1. Specifically, the Central Valley is home to the nation’s leading dairy industry, with over 80% of dairy farms and about 90% of dairy . cows of the state2. Previous measurements have shown that the Central Valley contributes to substantially elevated levels of CH43. This warrants attention given that CH4 is a powerful radiative forcer and ozone precursor, with a global warming potential (GWP) 25 times greater than carbon dioxide (CO2) over 100 years4. Dairy operations produce CH4 via enteric fermentation and manure management, which is thought to account for 27% and 25% of statewide CH4 emissions, respectively1. As such, California has set forth ambitious legislation to reduce greenhouse gas (GHG) emissions by 40% below 1990 levels by 2030 (Senate Bill 32 of 2016, Governor’s Executive Order B-30-15) and targets short-lived climate pollutants such as CH4 (i.e., Senate Bill 1383 of 2016). The CH4 budget, however, remains uncertain, with studies showing that CH4 enhancements in California are likely about 1.2 - 1.8 times larger than reported5. In particular, there is growing evidence that CH4 emissions from manure lagoons are underestimated. Although N2O is not yet targeted by the state, it is also a strong climate forcer with a GWP close to 300 times higher than CO2 in a 100-year time horizon4. Like CH4, N2O emissions from dairies also arise from manure management systems, and are generated from some of the same sources of dairy CH4 emissions. Field data is still variable, but previous studies attributed the majority of N2O emissions to barns, unlike dairy CH4 emissions, which are mostly expected from manure lagoons and slurry systems6.
The next largest emitter of N2O from dairy manure management is estimated to come from corrals and solid manure piles6. Interestingly, previous observations from manure lagoons and slurry stores also show a relatively large N2O flux6–11. Crop fields fertilized by manure and other synthetic fertilizers near dairies can also emit N2O12. However, it remains challenging to measure and determine the isotopic signature of N2O from different sources and microbial production pathways given that there are twelve possible molecules of N2O derived from two isotopes of N and three isotopes of O13. Consequently, the global N2O budget remains uncertain in part because very little is known about the isotopic signature of distinct N2O sources, and because there is large variation between isotope measurements of sources14. The primary goal of my research will be to study CH4 emissions from wet manure management in the Central Valley. Specifically, I will investigate the magnitude and spatial distribution of CH4 emissions from manure lagoons and examine their primary physical drivers. I also propose to study N2O isotopic molecules, in conjunction with CH4 emissions, across the landscape of a large dairy operation in California.
Erika Bucior, Ph.D. Candidate in Evolution, Ecology & Organismal Biology:
Understanding Climate Driven Drought Mortality Across Biomes
As the earth's climate continues to change, forests within a diverse set of biomes are experiencing increasingly frequent, severe, and longer periods of drought stress. The continued rise of global temperatures could radically alter the composition, structure, and biogeography of forests in many regions (Van Mantgem, 2007). Recent reviews of climate-induced mortality events include cases of large scale die-offs that span broad gradients of woody ecosystems, from monsoonal savannas with mean precipitation <400 mm/year, to tropical rainforests with mean precipitation >3000 mm/year (Allen, 2010). The diversity of ecosystems, from coastal tide pools to redwood forests and inland deserts, located within the UC reserve system, have been similarly recently impacted by a wide variety of drought frequencies and intensities. As local and global climate continues to change and drought recurrence increases, understanding subsequent changes within and between these systems is crucial in evaluating how ecosystem services and dynamics will be altered. Aside from the economic value associated with such stands of forest, the loss of biomass has ramifications that are closely tied to major climate and hydrological feedbacks, through loss of stored carbon and altered water cycling. Studying plant hydraulics bridges physiological regulation of transpiration to the environmental drivers of climate. However, the current parameters used to model plant drought responses are unresolved (Sperry, 2015). After a thorough review of the literature and preliminary evaluation, we believe that using sapwood capacitance as the primary functional trait in drought risk analysis will provide a more accurate prediction of mortality risk across species and plant functional types. By further understanding how climate drives mechanistic processes involved in hydraulic regulation, we can better predict changes in species composition and potentially mitigate loss of ecosystem function. Previous studies have parameterized tree mortality associated with drought, using the value of water potential where 50% of water transport capacity is lost (P50). However, observations of tree mortality in the field, in combination with direct measurements of P50 are weakly correlated, revealing a critical inconsistency in what physiologists believe to be the main mechanism in plant-water regulation under stress (Breshears, 2009). Based on accumulating evidence that functional tradeoffs play a significant role in hydraulic performance, we hypothesize that water movement in sapwood, described in terms of sapwood capacitance, is a better predictor of mortality and will provide a new axis to measure drought resistance.
Bridget Kelly, Ph.D. Candidate in Earth Sciences:
Stable Isotope Sclerochronology of the Late Miocene Oyster Pycnodonte heermanni from the Salton through region, California
In the Miocene, southern California experienced extension on a long and relatively straight rift basin parallel to the pre-existing continental margin. This extension and the subsequent detachment of Baja California from North America formed the Gulf of California. By the Late Miocene, approximately 6.5 Ma, marine waters of the proto-Gulf (the present-day Salton Trough region) had extended north to the San Gorgonio Pass (Winker and Kidwell 1996). The sediments found in the Salton Trough represent the first marine faunal deposits from when Baja separated from the mainland. Studying the marine fauna of the Salton Trough region will provide insight into the paleoecology and environment of the proto-Gulf of California in this region during the Miocene. Oysters secrete the building material CaCO3 in incremental bands. Using sclerochronology, the marine equivalent of dendrochronology, I can examine these growth bands on the hinge of the oyster. Because shells incorporate ions from the surrounding water into their shells, oyster shells contain a biogeochemical record of the environmental and climatic conditions experienced throughout their lifetimes (Jones 1985, Jones and Quitmyer 1996). Previous work on fossil oysters of the genus Crassostrea has yielded robust isotopic results (Kirby 2000, Surge et al. 2008, Durham et al. 2017) suggesting that fossil oysters are suitable for isotopic research. Although some other organisms do not precipitate their shells in equilibrium with seawater (Brenchley and Harper 1998), the vital effects (physiologic effects) among mollusks are minimal (Jones 1985). The aim of this study is to conduct a growth rate analysis of the Miocene oyster Pycnodonte heermanni. I will test the hypotheses that: (1) the large shell size of the P. heermanni was the result of rapid ontogenic growth and not due to increase longevity; and (2) the pycnodontids ceased growth during the warmest season of the year.
2017 Award Recipients
Lorena Villanueva-Almanza, Ph.D. Candidate in Botany & Plant Sciences:
Botanical history and taxonomic revision of the genus Washingtonia
Washingtonia (Arecaceae) is an American genus of palms composed of two species, W. filifera and W. robusta. The first one occurs naturally in Arizona, southern California, and north Baja California, while W. robusta is present in the Peninsula of Baja California, from latitude 30" to the Cape Region at 23", and in Sonora, mainland Mexico, where it has a very narrow distribution. Both palms have been an important element for the survival of native people even before the arrival of Jesuit missionaries to Baja California in the seventeenth century and continue to be today. Both species have been widely cultivated in California since 1874, and W. robusta is currently one of the most widely cultivated palms of the world. During the early years of cultivation, seeds of both W. filifera and W. robusta were being grown without knowledge neither of their taxonomic identity nor their geographic origin, due in part, to great morphological variation in both species. Poor understanding of its morphology led either to the description of numerous new species (now mostly reduced to synonyms) or to an oversimplification of the genus resulting in the traditional 2-species circumscription. Accurate knowledge on the distribution of the genus is missing because of lack of fieldwork in its natural range, which is reflected in fragmentary herbaria collections. Washingtonia, in a way, has been the elephant of a safari: extensively photographed, but rarely collected. Variable taxonomic circumscription and imprecise species distribution has done little to clarify the identity of the palms brought into cultivation in the nineteenth century. This research is the first comprehensive review of the earliest horticultural records, letters, and nursery catalogs concerning Washingtonia in an attempt to clarify the taxonomic identity and distribution range of both species, since none of them have useful type specimens. The aims of my research are 1) to evidence the poor reliability of the most recent taxonomic treatment of the genus Washingtonia (Bailey, 1936), 2) challenge the long held idea that the genus is composed of two species, and 3) identify the origin of the seeds brought into cultivation using historical records.
Jonathan Nye, Ph.D. Candidate in Environmental Science:
Paleoecology and the Anthropocene at the end of the world: Marine food web and population dynamics in Tierra del Fuego
At the intersection between the Atlantic, Pacific and Southern oceans, Tierra del Fuego and the Beagle Channel are physical and biological nexus points that are poised to be highly influenced by climate change. Such changes can alter the function and significance of species within an ecosystem. One way to identify effects of climate and human activity on an ecosystem is by comparing Holocene and historic food webs, by measuring changes in food chain length and fluctuation in species’ niche and population. Graduate student Jonathan Nye aims to address three primary questions: (1) How has the marine ecosystem near Tierra del Fuego changed over time, (2) How have humans influenced and been influenced by changes in this ecosystem and (3) What are the characteristics and changes in population of Southern Fur seals in the Holocene?
Elizabeth Deyett, Ph.D. Candidate in Genetics, Genomics and Bioinformatics:
The Grape Expectations: Discovering Alternative Strategies for Pest Management
Global climate change and rise in population pose a great threat to both our agricultural system and food security. As regions grow warmer, insect populations increase and begin to migrate and invade new production areas, affecting agricultural productivity, and viability. To keep up with humanity's food consumption, agriculture has turned to the use of copious amounts of pesticides to avoid pathogens and increase crop yield. These pesticides have been linked to a number of environmental and ecosystem changes ranging from amphibian population declines to groundwater contamination. Pesticide residues also build up in food, becoming a potential hazard to the consumer. It’s estimated that pesticides have been linked to $15 billion dollars in medical bills in 2005, as well as incalculable environmental costs just within the US. Additionally, resistance to pesticides continues to grow, causing farmers to increase their usage. The need for novel innovative and alternative methods to implement for sustainable agricultural management, both for food security and environmental health, is accelerating as this issues become more prominent. In the last decade, numerous microbiome studies have shown the beneficial impact microbes have on both plant and animal health. This suggests that microbes can be used as an alternative or in addition to crop management strategy, reducing harmful pesticide build-up.
To better understand the highly dynamic microbial ecosystems in agriculture, my work focuses on grapevines and the common bacterial pathogen Xylella fastidiosa. Xylella fastidiosa (Xf) is a cosmopolitan pathogen affecting major economic crops including grape, citrus, almond and olive. This xylem dwelling bacterium is spread by sharpshooters insects and is capable of developing into Pierce’s disease (PD), where the pathogen obstructs the xylem, leading to the death of the plant. A class of sharpshooters have recently been introduced in southern California and global warming has expanded their geographical range to northern California. This brings the insect close to the heart of winegrape production, in Napa and Sonoma valleys. These sharpshooters are more efficient vectors of the disease and, if they become established, would have a devastating effect on the wine industry. The only management strategy currently for PD is controlling the vector through pesticides. In grapevines, Xf is responsible for $92 million a year in lost revenue. My project sets out to understand the pathogen-microbiome-plant interactions using PD and grapevine as a model and establishing ways to manipulate this natural interaction to provide optimal benefit to the host.