Digital Commons Network^™

Soil Carbon Cycling Proxies: Understanding Their Critical Role In Predicting Climate Change Feedbacks, Vanessa L. Bailey, Ben Bond-Lamberty, Kristen M. Deangelis, A. Stuart Grandy, Christine V. Hawkes, Kate Heckman, Kate Lajtha, Richard P. Phillips, Benjamin N. Sulman, Katherine E. O. Todd-Brown, Matthew D. Wallenstein

Faculty Publications

The complexity of processes and interactions that drive soil C dynamics necessitate the use of proxy variables to represent soil characteristics that cannot be directly measured (correlative proxies), or that aggregate information about multiple soil characteristics into one variable (integrative proxies). These proxies have proven useful for understanding the soil C cycle, which is highly variable in both space and time, and are now being used to make predictions of the fate and persistence of C under future climate scenarios. However, the C pools and processes that proxies represent must be thoughtfully considered in order to minimize uncertainties in empirical …

Insights Into Land Plant Evolution Garnered From The Marchantia Polymorpha Genome, John L. Bowman, Takayuki Kohchi, Katsuyuki T. Yamato, Jerry Jenkins, Shengqiang Shu, Kimitsune Ishizaki, Shohei Yamaoka, Ryuichi Nishihama, Yasukazu Nakamura, Frédéric Berger, Catherine Adam, Shiori Sugamata Aki, Felix Althoff, Takashi Araki, Mario A. Arteaga-Vazquez, Sureshkumar Balasubrmanian, Kerrie Barry, Diane Bauer, Christian R. Boehm, Liam Briginshaw, Juan Caballero-Perez, Bruno Catarino, Feng Chen, Shota Chiyoda, Mansi Chovatia, Kevin M. Davies, Mihails Delmans, Taku Demura, Tom Dierschke, Liam Dolan, Tomokazu Kawashima

Plant and Soil Sciences Faculty Publications

The evolution of land flora transformed the terrestrial environment. Land plants evolved from an ancestral charophycean alga from which they inherited developmental, biochemical, and cell biological attributes. Additional biochemical and physiological adaptations to land, and a life cycle with an alternation between multicellular haploid and diploid generations that facilitated efficient dispersal of desiccation tolerant spores, evolved in the ancestral land plant. We analyzed the genome of the liverwort Marchantia polymorpha, a member of a basal land plant lineage. Relative to charophycean algae, land plant genomes are characterized by genes encoding novel biochemical pathways, new phytohormone signaling pathways (notably auxin), …

Nitrate Leaching From Sand And Pumice Geomedia Amended With Pyrogenic Carbon Materials, James Jihoon Kang, Marissa Davila, Sergio Mireles, Jungseok Ho

School of Earth, Environmental, & Marine Sciences Faculty Publications

There is increasing interest in using pyrogenic carbon as an adsorbent for aqueous contaminants in stormwater. The objective of this study was to investigate pyrogenic carbon materials as an amendment to geomedia to reduce nitrate leaching. Batch adsorption and column experiments were conducted to evaluate the performance of a commercial activated carbon and two biochars incorporated (5% by weight) into sand and pumice columns. The batch adsorption with 50 mg L−1 of nitrate solution showed that only activated carbon resulted in a substantial adsorption for nitrate up to 41%. Tested biochars were not effective in removing aqueous nitrate and even …

The Role Of Young Environmental Activists In Iceland And Furthering Youth Engagement With Environmental Issues, Story Schwantes

Independent Study Project (ISP) Collection

This paper looks at the role of youth environmental activism in Iceland and how these actors view their work in a country which has long held a reputation as one of the greenest in the world. Much of the credit for that distinction goes not to careful choices, sacrifice, or excellent stewardship but rather to its ideal geography providing massive geothermal energy which Iceland turns into electricity, a clean renewable source. So are there young environmental activists in Iceland, and if so what do they do? Short answer: yes, and they study and talk. The long answer is more complex. …

Geology Of The Middle Member Of The Bakken Formation In Divide County, North Dakota, Mandy Brewer

Graduate Theses & Non-Theses

The Upper Devonian-Lower Mississippian Bakken Formation of Williston Basin is a large unconventional oil and gas play consisting of a lower shale member, a middle member, and an upper shale member. The middle member is a production target because it contains porosity and petroleum expelled from the shale members around it. Variable production and sweet spots of the Bakken in the study area of Divide County, ND and 15 miles around Divide County in the USA prompted a closer look at middle member Bakken sediments. For this study, 606 wells were correlated and thin sections from two wells located 10.17 …

Agricultural Responses To Climate Change: A Study Of Adaptive Farming Methods In Kizanda Village, Bailey Smith-Helman

Independent Study Project (ISP) Collection

Agriculture is vital to the economic and social systems in Tanzania, composing 30% of the country’s GDP as well as 80% of employment (FAO, 2014). Despite agriculture’s important role, it remains one of the most vulnerable sectors to climate change. Current trends project global average temperature to increase by 0.8-2.6 degrees Celsius, leaving farmers to face changes in rainfall, soil quality, and new pests and diseases (IPCC, 2007). Farmers will be forced to adapt to the changing climate if they are to sustain their livelihoods and the Tanzanian economy. For these reasons, it is important to understand the types of …

A Near-Global Atmospheric Distribution Of N2o Isotopologues, Peter F. Bernath, Mahdi Yousefi, Eric Buzan, Chris D. Boone

Chemistry & Biochemistry Faculty Publications

The distributions of the four most abundant isotopologues and isotopomers (N₂O, ¹⁵NNO, N¹⁵NO, and NN¹⁸O of nitrous oxide have been measured in the Earth's stratosphere by infrared remote sensing with the Atmospheric Chemistry Experiment (ACE) Fourier transform spectrometer. These satellite observations have provided a near-global picture of N₂O isotopic fractionation. The relative abundances of the heavier species increase with altitude and with latitude in the stratosphere as the air becomes older. The heavy isotopologues are enriched by 20-30% in the upper stratosphere and even more over the poles. These observations are …

Selenium Distribution And Cycling In The Eastern Equatorial Pacific Ocean, Zoe Wambaugh

OES Theses and Dissertations

Oxygen minimum zones in oceanic waters have become increasingly important to the marine environment and society. Low oxygen waters affect not only the distribution and abundance of marine organisms, but also impact the solubility and transport of trace elements that are of biological importance, with the chemical speciation and solubility depending on the actual redox poise of the waters. One redox sensitive trace element of interest is selenium, which can be both toxic and essential for organisms, depending on its chemical speciation. In 2013, the US GEOTRACES program completed the GP16 transect from Peru to Tahiti, going through the oxygen …

A Novel Diffuse Fraction-Based Two-Leaf Light Use Efficiency Model: An Application Quantifying Photosynthetic Seasonality Across 20 Ameriflux Flux Tower Sites, Hao Yan, Shao-Qiang Wang, Kai-Liang Yu, Bin Wang, Qin Yu, Gil Bohrer, Dave Billesbach, Rosvel Bracho, Abdullah F. Rahman, Herman H. Shugart

School of Earth, Environmental, & Marine Sciences Faculty Publications

Diffuse radiation can increase canopy light use efficiency (LUE). This creates the need to differentiate the effects of direct and diffuse radiation when simulating terrestrial gross primary production (GPP). Here, we present a novel GPP model, the diffuse-fraction-based two-leaf model (DTEC), which includes the leaf response to direct and diffuse radiation, and treats maximum LUE for shaded leaves (ɛmsh defined as a power function of the diffuse fraction (Df)) and sunlit leaves (ɛmsu defined as a constant) separately. An Amazonian rainforest site (KM67) was used to calibrate the model by simulating the linear relationship …

Linear And Nonlinear Effects Of Temperature And Precipitation On Ecosystem Properties In Tidal Saline Wetlands, Laura C. Feher, Michael J. Osland, Kereen T. Griffith, James B. Grace, Rebecca J. Howard, Camille L. Stagg, Nicholas M. Enwright, Ken W. Krauss, Christopher A. Gabler, Richard H. Day, Kerrylee Rogers

School of Earth, Environmental, & Marine Sciences Faculty Publications

Climate greatly influences the structure and functioning of tidal saline wetland ecosystems. However, there is a need to better quantify the effects of climatic drivers on ecosystem properties, particularly near climate-sensitive ecological transition zones. Here, we used climate- and literature-derived ecological data from tidal saline wetlands to test hypotheses regarding the influence of climatic drivers (i.e., temperature and precipitation regimes) on the following six ecosystem properties: canopy height, biomass, productivity, decomposition, soil carbon density, and soil carbon accumulation. Our analyses quantify and elucidate linear and nonlinear effects of climatic drivers. We quantified positive linear relationships between temperature and above-ground productivity …

Potential For Natural Evaporation As A Reliable Renewable Energy Resource, Ahmet-Hamdi Cavusoglu, Xi Chen, Pierre Gentine, Ozgur Sahin

Advanced Science Research Center

About 50% of the solar energy absorbed at the Earth’s surface drives evaporation, fueling the water cycle that affects various renewable energy resources, such as wind and hydropower. Recent advances demonstrate our nascent ability to convert evaporation energy into work, yet there is little understanding about the potential of this resource. Here we study the energy available from natural evaporation to predict the potential of this ubiquitous resource. We find that natural evaporation from open water surfaces could provide power densities comparable to current wind and solar technologies while cutting evaporative water losses by nearly half. We estimate up to …

Fungal Community Homogenization, Shift In Dominant Trophic Guild, And Appearance Of Novel Taxa With Biotic Invasion, Mark A. Anthony, Serita D. Frey, Kristina A. Stinson

Faculty Publications

Invasion by non-native plants may fundamentally restructure the soil fungal community. The invasive plant, Alliaria petiolata, produces secondary compounds suppressive to mycorrhizal fungi and may therefore be expected to have generally negative effects on other components of the fungal community. Here, we compared fungal biomass, diversity, community composition, and the relative abundance of fungal trophic guilds, along with edaphic properties of soils collected from uninvaded and invaded plots across six temperate forests. Invaded plots were differentiated from uninvaded plots by lower variation in fungal community composition (beta diversity) and soil properties, higher fungal richness and community evenness (alpha diversity), and …

Factors Associated With Bat Mortality At Wind Energy Facilities In The United States, Maureen Thompson, Julie A. Beston, Matthew Etterson, Jay E. Diffendorfer, Scott R. Loss

United States Environmental Protection Agency: Publications

Hundreds of thousands of bats are killed annually by colliding with wind turbines in the U.S., yet little is known about factors causing variation in mortality across wind energy facilities. We conducted a quantitative synthesis of bat collision mortality with wind turbines by reviewing 218 North American studies representing 100 wind energy facilities. This data set, the largest compiled for bats to date, provides further evidence that collision mortality is greatest for migratory tree-roosting species (Hoary Bat [Lasiurus cinereus], Eastern Red Bat [Lasiurus borealis], Silver-haired Bat [Lasionycteris noctivagans]) and from July to October. Based …

Climate Controls Over The Net Carbon Uptake Period And Amplitude Of Net Ecosystem Production In Temperate And Boreal Ecosystems, Zheng Fu, Paul C. Stoy, Yiqi Luo, Jiquan Chen, Jian Sun, Leonardo Montagnani, Georg Wohlfahrt, Abdullah F. Rahman, Serge Rambal, Christian Bernhofer

School of Earth, Environmental, & Marine Sciences Faculty Publications

Highlights

• The start of net C uptake was determined by spring temperature in DBF and EF.

• Summer precipitation determined NEPmax anomalies in DBF and GRA.

• Climate controls annual NEP variability by regulating CUP and NEPmax.

Abstract

The seasonal and interannual variability of the terrestrial carbon cycle is regulated by the interactions of climate and ecosystem function. However, the key factors and processes determining the interannual variability of net ecosystem productivity (NEP) in different biomes are far from clear. Here, we quantified yearly anomalies of seasonal and annual NEP, net carbon uptake period (CUP), and the maximum daily NEP (NEPmax) …

N2o Emissions From California Farmlands: A Review, Elizabeth Verhoeven, Engil Isadora Pujol Pereira, Charlotte Decock, Gina Garland, Taryn Kennedy, Emma Suddick, William Horwath, Johan Six

School of Earth, Environmental, & Marine Sciences Faculty Publications

Of the greenhouse gases emitted from cropland, nitrous oxide (N2O) has the highest global warming potential. The state of California acknowledges that agriculture both contributes to and is affected by climate change, and in 2016 it adopted legislation to help growers reduce emissions of greenhouse gases, explicitly including N2O. Nitrous oxide emissions can vary widely due to environmental and agronomic factors with most emission estimates coming from temperate grain systems. There is, however, a dearth of emission estimates from perennial and vegetable cropping systems commonly found in California's Mediterranean climate. Therefore, emission factors (EFs) specific to California conditions are needed …

Climate, Wildfire, And Erosion Ensemble Foretells More Sediment In Western Usa Watersheds, John B. Sankey, Jason Kreitler, Todd J. Hawbaker, Jason L. Mcvay, Mary Ellen Miller, Erich R. Mueller, Nicole M. Vaillant, Scott E. Lowe, Temuulen T. Sankey

Michigan Tech Research Institute Publications

The area burned annually by wildfires is expected to increase worldwide due to climate change. Burned areas increase soil erosion rates within watersheds, which can increase sedimentation in downstream rivers and reservoirs. However, which watersheds will be impacted by future wildfires is largely unknown. Using an ensemble of climate, fire, and erosion models, we show that postfire sedimentation is projected to increase for nearly nine tenths of watersheds by >10% and for more than one third of watersheds by >100% by the 2041 to 2050 decade in the western USA. The projected increases are statistically significant for more than eight …

The Soybean Rfg1 Gene Restricts Nodulation By Sinorhizobium Fredii Usda193, Yinglun Fan, Jinge Liu, Shanhua Lyu, Qi Wang, Shengming Yang, Hongyan Zhu

Plant and Soil Sciences Faculty Publications

Sinorhizobium fredii is a fast-growing rhizobial species that can establish a nitrogen-fixing symbiosis with a wide range of legume species including soybeans (Glycine max). In soybeans, this interaction shows a high level of specificity such that particular S. fredii strains nodulate only a limited set of plant genotypes. Here we report the identification of a dominant gene in soybeans that restricts nodulation with S. fredii USDA193. Genetic mapping in an F2 population revealed co-segregation of the underlying locus with the previously cloned Rfg1 gene. The Rfg1 allele encodes a member of the Toll-interleukin receptor/nucleotide-binding site/leucine-rich repeat class of …

Desert Pool {If Every Desert Was Once A Sea}, Karen Miranda Abel

The Goose

Desert Pool {If every desert was once a sea} is a site-specific art project by Canadian artist Karen Miranda Abel completed in 2016 while artist-in-residence at Joya: arte + ecología, an arts-led research centre situated in an alpine desert within a national park in southern Spain. The elemental installation represents an envisioning of the ancient sea that occupied the Sierra de María-Los Vélez Natural Park millions of years before the current desert ecology, a time when its highest mountain peaks may have been islands.

Lidar Aboveground Vegetation Biomass Estimates In Shrublands: Prediction, Uncertainties And Application To Coarser Scales, Aihua Li, Shital Dhakal, Nancy F. Glenn, Lucas P. Spaete

Geosciences Faculty Publications and Presentations

Our study objectives were to model the aboveground biomass in a xeric shrub-steppe landscape with airborne light detection and ranging (Lidar) and explore the uncertainty associated with the models we created. We incorporated vegetation vertical structure information obtained from Lidar with ground-measured biomass data, allowing us to scale shrub biomass from small field sites (1 m subplots and 1 ha plots) to a larger landscape. A series of airborne Lidar-derived vegetation metrics were trained and linked with the field-measured biomass in Random Forests (RF) regression models. A Stepwise Multiple Regression (SMR) model was also explored as a comparison. Our results …

East African Weathering Dynamics Controlled By Vegetation-Climate Feedbacks, Sarah J. Ivory, Michael M. Mcglue, Geoffrey S. Ellis, Adam Boehlke, Anne-Marie Lézine, Annie Vincens, Andrew S. Cohen

Earth and Environmental Sciences Faculty Publications

Tropical weathering has important linkages to global biogeochemistry and landscape evolution in the East African rift. We disentangle the influences of climate and terrestrial vegetation on chemical weathering intensity and erosion at Lake Malawi using a long sediment record. Fossil pollen, microcharcoal, particle size, and mineralogy data affirm that the detrital clays accumulating in deep water within the lake are controlled by feedbacks between climate and hinterland forest composition. Particle-size patterns are also best explained by vegetation, through feedbacks with lake levels, wildfires, and erosion. We develop a new source-to-sink framework that links lacustrine sedimentation to hinterland vegetation in tropical …

Managing Nitrous Oxide Emissions In Agricultural Fields, Mark S. Coyne, Wei Ren

Plant and Soil Sciences Research Report

Agriculture is a major contributor to atmospheric nitrous oxide (N₂O) (Smith et al., 2014; Tian et al., 2015). Unfortunately, nitrous oxide destroys stratospheric ozone (O₃) which protects us from ultraviolet radiation (Cicerone, 1989) and it increases ground level O_3, whichis an air pollutant threatening human health and food production. Nitrous oxide is also 298 times more potent than an equivalent amount of carbon dioxide (CO₂) in terms of trapping and absorbing reflected solar radiation (Forster et al., 2007). Basic chemistry and physics assure us that increased levels of N₂O in the …

Catchment-Scale Alder Cover Controls Nitrogen Fixation In Boreal Headwater Streams, Daniel L. Hiatt, Caleb J. Robbins, Jeffrey A. Back, Pamela K. Kostka, Robert D. Doyle, Coowe M. Walker, Mark C. Rains, Dennis F. Whigham, Ryan S. King

School of Geosciences Faculty and Staff Publications

Alder (Alnus spp.) is a woody plant with bacterial symbionts that fix atmospheric N2into bioavailable N. We studied 12 North American boreal headwater streams spanning a steep gradient of catchment alder cover (0–27%) to test the hypothesis that increasing inputs of inorganic N associated with increasing alder cover would reduce or eliminate in-stream benthic N2 fixation. We measured N2 fixation rates, chlorophyll a, and ash-free dry mass (AFDM) of periphyton in early (May) and late (August) summer 2011. Dissolved inorganic N (DIN) concentrations, composed almost entirely of NO3/NO2-N, ranged from below detection limits to nearly 2 mg/L and …

Conduction Plus Convection Heat Flow Modeling For The Linga Complex, Peruvian Coastal Batholith, Luciano Uriel González Olivares

Loma Linda University Electronic Theses, Dissertations & Projects

Factors affecting the thermal evolution of the Linga magmatic intrusion in the Ica-Pisco area of the Peruvian Coastal Batholith were studied using field work, petrography, geochemistry data, and computer modeling. Field work and petrography involved collecting samples for geochemical analysis and documenting widespread propylitic and potassic hydrothermal alteration. Major element geochemistry was used to estimate rock density, viscosity, liquidus temperature, and water content. The δ18O values of seven fresh samples showed a slightly increasing west-east and old-young trend of approximately 7-8‰, indicating an increasing crustal component. The δ18O and δD values for eleven altered samples indicated that alteration came mostly …

Anthropogenic Infilling Of A Bermudian Sinkhole And Its Impact On Sedimentation And Benthic Foraminifera In The Adjacent Anchialine Cave Environment, Jacquelyn N. Cresswell, Peter J. Van Hengstum, Thomas M. Iliffe, Bruce E. Williams, Gil Nolan

International Journal of Speleology

In the mid-20^th century, an inland brackish pond from Bermuda, known as Eve’s Pond, was filled with marine sediment from an adjacent coastal lagoon. At this time, an eyewitness reported “…sediment billowing out of the Green Bay Cave for days…”, which is a marine-dominated anchialine cave located proximal to the former location of Eve’s Pond (~200 m). The purpose of this study was to evaluate the potential impact of this infilling event on cave sedimentation and benthic meiofaunal communities, as proxied by the unicellular protists foraminifera that remain preserved in the sediment record. Eight sediment cores were collected from …

Controls On Erosion In The Western Tarin Basin: Implications For The Uplift Of Northwest Tibet And The Parmir, Peter D. Clift, Hongbo Zheng, Andrew Carter, Philipp Böning, Tara N. Jonell, Hannah Schorr, Xin Shan, Katharina Pahnke, Xiaochun Wei, Tammy M. Rittenour

Geosciences Faculty Publications

We present here bulk sediment major element chemistry, Nd and Sr isotope ratios, and detrital apatite fission-track (AFT) and U-Pb zircon ages to characterize the provenance of the southwestern Taklimakan Desert (northwest China) and the three major rivers draining this region. We establish the spatial and temporal controls on erosion and sediment transport in the modern Tibetan rain shadow. The Hotan River drains the North Kunlun block and is characterized by zircon populations at 160–230 Ma and 370–520 Ma. The Yarkand River shares these grains with the Hotan, but also has a very prominent zircon population at 40–160 Ma, which …

Differential Preservation Of Vertebrates In Southeast Asian Caves, Julien Louys, Shimona Kealy, Sue O'Connor, Gilbert J. Price, Stuart Hawkins, Ken Aplin, Yan Rizal, Jahdi Zaim, Mahirta, Daud A. Tanudirjo, Wahyu Dwijo Santoso, Ati Rati Hidayah, Agus Trihascaryo, Rachel Wood, Joseph Bevitt, Tara Clark

International Journal of Speleology

Caves have been an important source of vertebrate fossils for much of Southeast Asia, particularly for the Quaternary. Despite this importance, the mechanisms by which vertebrate remains accumulate and preserve in Southeast Asian caves has never been systematically reviewed or examined. Here, we present the results of three years of cave surveys in Indonesia and Timor-Leste, describing cave systems and their attendant vertebrate accumulations in diverse geological, biogeographical, and environmental settings. While each cave system is unique, we find that the accumulation and preservation of vertebrate remains are highly dependent on local geology and environment. These factors notwithstanding, we find …

Model Application Niche Analysis: Assessing The Transferability And Generalizability Of Ecological Models, Jessica B. Moon, Theodore H. Dewitt, Melissa N. Errend, Randall J. F. Bruins, Mary E. Kentula, Sarah J. Chamberlain, M. Siobhan Fennessy, Kusum J. Naithani

United States Environmental Protection Agency: Publications

The use of models by ecologists and environmental managers, to inform environmental management and decision-making, has grown exponentially in the past 50 yr. Due to logistical, economical, and theoretical benefits, model users frequently transfer preexisting models to new sites where data are scarce. Modelers have made significant progress in understanding how to improve model generalizability during model development. However, models are always imperfect representations of systems and are constrained by the contextual frameworks used during their development. Thus, model users need better ways to evaluate the possibility of unintentional misapplication when transferring models to new sites. We propose a method …

Effects Of Cultivar And Maternal Environment On Seed Quality In Vicia Sativa, Rong Li, Lijun Chen, Yanpei Wu, Rui Zhang, Carol C. Baskin, Jerry M. Baskin, Xiaowen Hu

Biology Faculty Publications

Production of high quality seeds is of fundamental importance for successful crop production. However, knowledge of the effects of increased temperature resulting from global warming on seed quality of alpine species is limited. We investigated the effect of maternal environment on seed quality of three cultivars of the leguminous forage species Vicia sativa, giving particular attention to temperature. Plants of each cultivar were grown at 1700 and 3000 m a.s.l., and mass, germination, electrical conductivity (EC) of leakage and longevity were determined for mature seeds. Seeds of all three cultivars produced at the low elevation had a significantly lower …

Nitrogen And Carbon Isotopic Dynamics Of Subarctic Soils And Plants In Southern Yukon Territory And Its Implications For Paleoecological And Paleodietary Studies, Farnoush Tahmesabi, Fred J. Longstaffe, Grant Zazula, Bruce Bennett

Earth Sciences Publications

We examine here the carbon and nitrogen isotopic compositions of bulk soils (8 topsoil and 7 subsoils, including two soil profiles) and five different plant parts of 79 C₃ plants from two main functional groups: herbs and shrubs/subshrubs, from 18 different locations in grasslands of southern Yukon Territory, Canada (eastern shoreline of Kluane Lake and Whitehorse area). The Kluane Lake region in particular has been identified previously as an analogue for Late Pleistocene eastern Beringia. All topsoils have higher average total nitrogen δ¹⁵N and organic carbon δ¹³C than plants from the same sites with a …

Genetic And Biological Studies On Solanum Plants: Insights Into The Leaf Wax Alkane Paleoclimate Proxy, Amanda Lorraine Dorothy Bender

Arts & Sciences Graduate Student Theses and Dissertations

The hydrogen isotopic composition (δ2H) of precipitation records fluxes of water in the hydrological cycle, and can reflect climatic variables such as temperature and humidity. Leaf wax n-alkanes can record δ2H of precipitation; consequently, n-alkanes extracted from sedimentary archives are commonly used as proxies for paleoenvironmental reconstruction. However, the utility of the leaf wax paleoclimate proxy is modulated by uncertainty about how physiological processes affect hydrogen isotopic compositions during alkane biosynthesis. This work aims to improve our understanding of the leaf wax paleoclimate proxy by examining biological and environmental sources of variability on cuticular leaf waxes. We used Solanum (tomato) …