Life Sciences Commons^™

The Emerging Contribution Of Social Wasps To Grape Rot Disease Ecology, Anne A. Madden, Sean D. Boyden, Jonathan-Andrew N. Soriano, Tyler B. Corey, Jonathan W. Leff, Noah Fierer, Philip T. Starks

School of Biological Sciences: Faculty Publications

Grape sour (bunch) rot is a polymicrobial disease of vineyards that causes millions of dollars in lost revenue per year due to decreased quality of grapes and resultant wine. The disease is associated with damaged berries infected with a community of acetic acid bacteria, yeasts, and filamentous fungi that results in rotting berries with high amounts of undesirable volatile acidity. Many insect species cause the initial grape berry damage that can lead to this disease, but most studies have focused on the role of fruit flies in facilitating symptoms and vectoring the microorganisms of this disease complex. Like fruit flies, …

First-Year And Non-First-Year Student Expectations Regarding In-Class And Out-Of-Class Learning Activities In Introductory Biology, Tanya L. Brown, Brian A. Couch

School of Biological Sciences: Faculty Publications

National calls for teaching transformation build on a constructivist learning theory and propose that students learn by actively engaging in course activities and interacting with other students. While interactive pedagogies can improve learning, they also have the potential to challenge traditional norms regarding class participation and learning strategies. To better understand the potential openness of students to interactive teaching practices, we administered a survey during the first week of two sections of an introductory biology course to characterize how students envisioned spending time during class as well as what activities they expected to complete outside of class during non-exam weeks …

Rewiring Metabolism Under Oxygen Deprivation: Naked Mole-Rats Evolved A Means To Cope With Anoxia, Jay F. Storz, Grant B. Mcclelland

Jay F. Storz Publications

When faced with a reduced availability of oxygen in the environment (hypoxia), vertebrates can make a variety of respiratory, cardiovascular, and hematological adjustments to ensure an uninterrupted supply of oxygen to the cells of metabolizing tissues (1, 2). These are adaptive solutions for “aerobic organisms in an aerobic world” (3). Coping with the complete absence of oxygen (anoxia) requires more fundamental alterations of cellular metabolism that are typically nothing more than emergency stopgap measures to buy time until the oxygen supply is (hopefully) reestablished (4). On page 307 of this issue [Science 356 (6335)], Park et al. (5) identify a …

Metabolic Investigations Of The Molecular Mechanisms Associated With Parkinson’S Disease, Robert Powers, Shulei Lei, Annadurai Anandhan, Darrell D. Marshall, Bradley Worley, Ronald Cerny, Eric D. Dodds, Yuting Huang, Mihalis I. Panayiotidis, Aglaia Pappa, Rodrigo Franco

Robert Powers Publications

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by fibrillar cytoplasmic aggregates of α-synuclein (i.e., Lewy bodies) and the associated loss of dopaminergic cells in the substantia nigra. Mutations in genes such as α -synuclein (SNCA) account for only 10% of PD occurrences. Exposure to environmental toxicants including pesticides and metals (e.g., paraquat (PQ) and manganese (Mn)) is also recognized as an important PD risk factor. Thus, aging, genetic alterations, and environmental factors all contribute to the etiology of PD. In fact, both genetic and environmental factors are thought to interact in the promotion of idiopathic PD, but the mechanisms …

Isolation And Genetic Identification Of Spore-Forming Bacteria Associated With Concentrated-Milk Processing In Nebraska, Bismarck Antonio Martinez, Jayne E. Stratton, Andreia Bianchini

Department of Food Science and Technology: Faculty Publications

Spore-forming bacteria are heat-resistant microorganisms capable of surviving and germinating in milk after pasteurization. They have been reported to affect the quality of dairy products by the production of enzymes (lipolytic and proteolytic) under low-temperature conditions in fluid milk, and have become a limiting factor for milk powder in reaching some selective markets. The objective of this research was to isolate and identify the population of spore-forming bacteria (psychrotrophic and thermophilic strains) associated with concentrated milk processing in Nebraska. During 2 seasons, in-process milk samples from a commercial plant (raw, pasteurized, and concentrated) were collected and heat-treated (80°C/12 min) to …

Peanut Allergen Threshold Study (Pats): Novel Single-Dose Oral Food Challenge Study To Validate Eliciting Doses In Children With Peanut Allergy, Jonathan O'B. Hourihane, Katrina J. Allen, Wayne G. Shreffler, Gillian Dunngalvin, Julie A. Nordlee, Giovanni A. Zurzolo, Audrey Dunngalvin, Lyle C. Gurrin, Joseph L. Baumert, Steve L. Taylor

Department of Food Science and Technology: Faculty Publications

Background: Eliciting doses (EDs) of allergenic foods can be defined by the distribution of threshold doses for subjects within a specific population. The ED₀₅ is the dose that elicits a reaction in 5% of allergic subjects. The predicted ED₀₅ for peanut is 1.5 mg of peanut protein (6 mg of whole peanut).

Objective: We sought to validate the predicted peanut ED05 (1.5 mg) with a novel single-dose challenge.

Methods: Consecutive eligible children with peanut allergy in 3 centers were prospectively invited to participate, irrespective of previous reaction severity. Predetermined criteria for objective reactions were used …

Evolutionary History Of Chemosensory-Related Gene Families Across The Arthropoda, Seong-Il Eyun, Ho Young Soh, Marijan Posavi, James B. Munro, Daniel S.T. Hughes, Shwetha C. Murali, Jiaxin Qu, Shannon Dugan, Sandra L. Lee, Hsu Chao, Huyen Dinh, Yi Han, Harshavardhan Doddapaneni, Kim C. Worley, Donna M. Muzny, Eun-Ok Park, Joana C. Silva, Richard A. Gibbs, Stephen Richards, Carol Eunmi Lee

Nebraska Center for Biotechnology: Faculty and Staff Publications

Chemosensory-related gene (CRG) families have been studied extensively in insects, but their evolutionary history across the Arthropoda had remained relatively unexplored. Here, we address current hypotheses and prior conclusions on CRG family evolution using a more comprehensive data set. In particular, odorant receptors were hypothesized to have proliferated during terrestrial colonization by insects (hexapods), but their association with other pancrustacean clades and with independent terrestrial colonizations in other arthropod subphyla have been unclear. We also examine hypotheses on which arthropod CRG family is most ancient. Thus, we reconstructed phylogenies of CRGs, including those from new arthropod genomes and transcriptomes, and …

Biotic Interchange Has Structured Western Hemisphere Mammal Communities, Danielle Fraser, S. Kathleen Lyons

School of Biological Sciences: Faculty Publications

Aim.— Many hypotheses posit that species-rich tropical communities are dominated by speciesspecies interactions, apparent as competitive exclusion or character displacement, whereas species-poor temperate communities are dominated by species-environment interactions. Recent studies demonstrate a strong influence of macroevolutionary and biogeographic factors. We simultaneously test for the effects of species interactions, climate, and biotic interchange on Western Hemisphere mammal communities using a phylogenetic and functional diversity approach.

Location.— Western Hemisphere.

Time period.— Modern

Major taxa studied.— Mammalia

Methods.— Using Western Hemisphere mammal distributional and body mass data, we calculate body mass dispersion, phylogenetic diversity (Net Relatedness Index), and assemblage-averaged rates of co-occurrence …

Palynological Investigation Of Mummified Human Remains, Karl Reinhard, Marina Milanello Do Amaral, Nicole Wall

Karl Reinhard Publications

Pollen analysis was applied to a mummified homicide victim in Nebraska, U.S.A., to determine the location of death. A control sample showed the normal ambient pollen in the garage crime scene. Ambient windborne types, common in the air of the region, dominated the control. Internal samples were analyzed from the sacrum, intestine, and diaphragm. Microfossils were recovered from the rehydrated intestine lumen. The intestinal sample was dominated by Brassica (broccoli). The sacrum sample was high in dietary types but with a showing of ambient types. The pollen from the diaphragm was dominated by ambient pollen similar to the control samples. …

Distinct Fitness Costs Associated With The Knockdown Of Rnai Pathway Genes In Western Corn Rootworm Adults, Ke Wu, Carolina Camargo, Elane Fishilevich, Kenneth E. Narva, Xiuping Chen, Caitlin E. Taylor, Blair D. Siegfried

Department of Entomology: Faculty Publications

RNA interference (RNAi) based approaches can potentially be used to control insect pests. These approaches may depend on the usage of microRNA (miRNA) or double stranded RNA (dsRNA) mediated gene knockdown, which likely involves proteins that regulate these pathways, such as Argonaute 1 (Ago1), Argonaute 2 (Ago2), Dicer 1 (Dcr1), Dicer 2 (Dcr2), and Drosha in insects. We previously performed functional characterization of Ago2 and Dcr2 of western corn rootworm (WCR), Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae) and observed that knockdown of Ago2 and Dcr2 ameliorated the lethal effect induced by the dsRNA-mediated knockdown of an essential gene in WCR, thereby …

“Hummingbird” Floral Traits Interact Synergistically To Discourage Visitation By Bumble Bee Foragers, Robert J. Gegear, Rebecca Burns, Katharine A. Swoboda-Bhattarai

Department of Entomology: Faculty Publications

Pollination syndromes are suites of floral traits presumed to reflect adaptations to attract and utilize a “primary” type of animal pollinator. However, syndrome traits may also function to deter “secondary” flower visitors that reduce plant fitness through their foraging activities. Here we use the hummingbird-pollinated plant species Mimulus cardinalis as a model to investigate the potential deterrent effects of classic bird syndrome traits on bumble bee foragers. To establish that M. cardinalis flowers elicit an avoidance response in bees, we assessed the choice behavior of individual foragers on a mixed experimental array of M. cardinalis and its bee-pollinated sister species …

Native And Agricultural Forests At Risk To A Changing Climate In The Northern Plains, Linda A. Joyce, Gary Bentrup, Antony S. Cheng, Peter Kolb, Michele Schoeneberger, Justin Derner

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Native and agricultural forests in the Northern Plains provide ecosystem services that benefit human society—diversified agricultural systems, forest-based products, and rural vitality. The impacts of recent trends in temperature and disturbances are impairing the delivery of these services. Climate change projections identify future stressors of greater impact, placing at risk crops, soils, livestock, biodiversity, and agricultural and forest-based livelihoods. While these native and agricultural forests are also a viable option for providing mitigation and adaptation services to the Northern Plains, they themselves must be managed in terms of climate change risks. Because agricultural forests are planted systems, the primary approaches …

Nonprofit Pay In A Competitive Market: Wage Penalty Or Premium?, Christian King, Gregory B. Lewis

Department of Nutrition and Health Sciences: Faculty Publications

Two competing theories argue that the nonprofit sector pays differently: Nonprofit employees may accept lower pay to be able to do meaningful work for a good cause, or they may earn higher pay due to nonprofit organizations’ tax exemptions and weaker incentives to hold down wages. To test these opposing expectations, we use the 2005-2013 American Community Surveys to examine pay differences among registered nurses working for nonprofit, for-profit, and public hospitals. We also test hypotheses that public and nonprofit hospitals have smaller pay disparities by gender, race, and relationship status. We find that pay is highest in nonprofit hospitals, …

Role Of Oxygen Free Radicals, Nitric Oxide And Mitochondria In Mediating Cardiac Alterations During Liver Cirrhosis Induced By Thioacetamide, G. Jayakumar Amirtharaj, Sathish Kumar Natarajan, Anna Pulimood, K. A. Balasubramanian, Aparna Venkatraman, Anup Ramachandran

Department of Nutrition and Health Sciences: Faculty Publications

Thioacetamide (TAA) administration is widely used for induction of liver cirrhosis in rats, where reactive oxygen radicals (ROS) and nitric oxide (NO) participate in development of liver damage. Cardiac dysfunction is an important complication of liver cirrhosis, but the role of ROS or NO in cardiac abnormalities during liver cirrhosis is not well understood. This was investigated in animals after TAA-induced liver cirrhosis and temporal changes in oxidative stress, NO and mitochondrial function in the heart evaluated. TAA induced elevation in cardiac levels of nitrate before development of frank liver cirrhosis, without gross histological alterations. This was accompanied by an …

Movement Of Hypophthalmichthys Dna In The Illinois River Watershed By The Double-Crested Cormorant (Phalacrocorax Auritus), Michael P. Guilfoyle, Heather L. Farrington, Richard F. Lance, Katie C. Hanson-Dorr, Brian S. Dorr, Richard A. Fischer

United States Department of Agriculture Wildlife Services: Staff Publications

Paired throat and cloacal swabs, along with feather samples, from nesting Double-crested Cormorants (Phalacrocorax auritus) at two sites in Illinois, USA, were tested for presence of invasive bigheaded carp (Hypophthalmichthys spp.) DNA. We also used DNA from the feather calamus to determine cormorant sex. Throat and cloacal swabs from cormorants at both locations tested positive for DNA from silver carp (H. molitrix), but none tested positive for bighead carp (H. nobilis). Hypophthalmichthys DNA was not detected on feathers. There were no significant differences among positive Hypophthalmichthys DNA detection frequencies between cormorant sexes. To …

Estimating Population Density For Disease Risk Assessment: The Importance Of Understanding The Area Of Influence Of Traps Using Wild Pigs As An Example, Amy J. Davis, Bruce Leland, Michael J. Bodenchuk, Kurt C. Vercauteren, Kim M. Pepin

United States Department of Agriculture Wildlife Services: Staff Publications

Population density is a key driver of disease dynamics in wildlife populations. Accurate disease risk assessment and determination of management impacts on wildlife populations requires an ability to estimate population density alongside management actions. A common management technique for controlling wildlife populations to monitor and mitigate disease transmission risk is trapping (e.g., box traps, corral traps, drop nets). Although abundance can be estimated from trapping actions using a variety of analytical approaches, inference is limited by the spatial extent to which a trap attracts animals on the landscape. If the “area of influence” were known, abundance estimates could be converted …

Wetland Bird Abundance And Safety Implications For Military Aircraft Operations, Kent Andersson, Craig A. Davis, Bradley F. Blackwell, Jason R. Heinen

United States Department of Agriculture Wildlife Services: Staff Publications

Wetlands with associated avifauna can pose a substantial hazard to aviation safety, potentially increasing bird–aircraft collision (strike) risk when located near air operations areas.We modeled year-round use by wetland avifauna of Drummond Flats Wildlife Management Area (Drummond Flats), a wetland complex located within 10 km of Vance Air Force Base (AFB), Enid, Oklahoma, USA. Our objectives were to 1) quantify seasonal avifauna abundances at Drummond Flats; 2) test a priori models reflecting use by bird species recognized as hazardous to aviation safety relative to environmental factors including flooded wetland habitat and vegetation cover; 3) use these models to predict maximal …

The Roles Of Habitat And Intraguild Predation By Coyotes On The Spatial Dynamics Of Kit Foxes, Robert C. C. Lonsinger, Eric M. Gese, Larissa L. Bailey, Lisette P. Waits

United States Department of Agriculture Wildlife Services: Staff Publications

Intraguild predation (IGP) by a dominant predator can drive the spatial dynamics of a subordinate predator and may explain space-use patterns that deviate from theoretical predictions that species will use areas that maximize the availability of limited resources (resource availability hypothesis). Intraguild predation may suppress the distribution and abundance of mesopredators, but spatial resource partitioning may facilitate coexistence, with the subordinate carnivore utilizing suboptimal habitats. In arid systems, free-standing water was historically scarce, limiting the distribution of larger-bodied predators and offering large areas of refugia for smaller, arid-adapted species, such as the kit fox (Vulpes macrotis). In these …

Adaptation Of The Aesop’S Fable Paradigm For Use With Raccoons (Procyon Lotor): Considerations For Future Application In Non‑Avian And Non‑Primate Species, Lauren Stanton, Emily Davis, Shylo Johnson, Amy T. Gilbert, Sarah Benson-Amram

United States Department of Agriculture Wildlife Services: Staff Publications

To gain a better understanding of the evolution of animal cognition, it is necessary to test and compare the cognitive abilities of a broad array of taxa. Meaningful interspecies comparisons are best achieved by employing universal paradigms that standardize testing among species. Many cognitive paradigms, however, have been tested in only a few taxa, mostly birds and primates. One such example, known as the Aesop’s Fable paradigm, is designed to assess causal understanding in animals using water displacement. To evaluate the universal effectiveness of the Aesop’s Fable paradigm, we applied this paradigm to a previously untested taxon, the raccoon ( …

Tick Haller's Organ, A New Paradigm For Arthropod Olfaction: How Ticks Differ From Insects, Ann L. Carr, Robert D. Michell Iii, Anirudh Dhammi, Brooke W. Bissinger, Daniel E. Sonenshine, R. Michael Roe

Biological Sciences Faculty Publications

Ticks are the vector of many human and animal diseases; and host detection is critical to this process. Ticks have a unique sensory structure located exclusively on the 1st pairs of legs; the fore-tarsal Haller's organ, not found in any other animals, presumed to function like the insect antennae in chemosensation but morphologically very different. The mechanism of tick chemoreception is unknown. Utilizing next-generation sequencing and comparative transcriptomics between the 1st and 4th legs (the latter without the Haller's organ), we characterized 1st leg specific and putative Haller's organ specific transcripts from adult American dog ticks, Dermacentor variabilis. The …

Impact Of Disease On The Survival Of Three Commercially Fished Species, John M. Hoenig, Maya L. Groner, Matthew W. Smith, Wolfgang K. Vogelbein, David M. Taylor, Donald F. Landers Jr., John T. Swenarton, David T. Gauthier

Biological Sciences Faculty Publications

Recent increases in emergent infectious diseases have raised concerns about the sustainability of some marine species. The complexity and expense of studying diseases in marine systems often dictate that conservation and management decisions are made without quantitative data on population-level impacts of disease. Mark-recapture is a powerful, underutilized, tool for calculating impacts of disease on population size and structure, even in the absence of etiological information. We applied logistic regression models to mark-recapture data to obtain estimates of disease-associated mortality rates in three commercially important marine species: snow crab (Chionoecetes opilio) in Newfoundland, Canada, that experience sporadic epizootics …

The Conservation Status Of Marine Bony Shorefishes Of The Greater Caribbean, Kent E. Carptenter, Christi Linardich, Gina Ralph, N. Cox, D. R. Robertson, H. Harwell, A. Acero P., W. Anderson Jr., F. Barthelat, J. -L. Bouchereau, J. J. Brown, J. Buchanan, D. Buddo, B. Collette, M. Comeros-Raynal, M. Craig, M. Curtis, T. Defex, J. Dooley, W. Driggers Iii, C. Elfes Livsey, T. Fraser, R. Gilmore Jr., L. Grijalba Bendeck, A. Hines, R. Kishore, K. Lindeman, J. -P. Maréchal, J. Mceachran, R. Mcmanus, J. Moore, T. Munroe, H. Oxenford, F. Pezold, F. Pina Amargós, A. Polanco Fernandez, B. Polidoro, C. Pollock, R. Robins, B. Russell, C. Sayer, S. Williams

Biological Sciences Faculty Publications

The greater Caribbean biogeographic region covered in this report (representing 38 countries and territories) encompasses an outstanding marine bony shorefish richness of approximately 1,360 species, with many (53%) being endemic. This report provides an overview of the conservation status of greater Caribbean shorefishes, with detailed information available through the IUCN Red List, and gives recommendations.

Reproductive Competency And Mitochondrial Variation In Aged Syrian Hamster Oocytes, Fang Li, Frank J. Castora, Wentia Ford, Khalid Alarid, Howard W. Jones Jr., R. James Swanson

Biological Sciences Faculty Publications

The hamster is a useful model of human reproductive biology because its oocytes are similar to those in humans in terms of size and structural stability. In the present study we evaluated fecundity rate, ovarian follicular numbers, ova production, mitochondrial number, structure and function, and cytoplasmic lamellae (CL) in young (2–4 months) and old (12–18 months) Syrian hamsters (Mesocricetus auratus). Young hamsters had higher fertilisation rates and larger litters than old hamsters (100 vs 50% and 9.3 +/- 0.6 vs 5.5 +/- 0.6, respectively). Ovarian tissue from superovulated animals showed a 46% decrease in preantral follicles in old …

Acanthurus Albimento, A New Species Of Surgeonfish (Acanthuriformes: Acanthuridae) From Northeastern Luzon, Philippines, With Comments On Zoogeography, Kent E. Carpenter, Jeffrey T. Williams, Mudjekeewis D. Santos

Biological Sciences Faculty Publications

Acanthurus albimento is described as a new surgeonfish from northeastern Luzon from six specimens collected during extensive fish-market surveys in the Philippines. The new species is characterized by a distinctive white band below the lower jaw; many irregular, wavy, thin, blue lines on the head; a brown-orange pectoral fin with a bluish tinge on the outer membrane of the rays and a dark band on the posterior margin; a narrow rust-orange stripe along the base of the dorsal fin; and a large blackish caudal spine and sheath with the socket broadly edged in black. An analysis using the mitochondrial cytochrome …

Verbal Behaviors During Employment Interviews Of College Students With And Without Asd, Dennis James Bublitz, Katherine Fitzgerald, Maria Alarcon, Joanne D'Onofrio, Kristen Gillespie-Lynch

Publications and Research

BACKGROUND: Even well-educated people with ASD struggle with obtaining employment, partially due to social difficulties during interviews. Although increasing numbers of individuals with ASD are entering college, little research focuses on this population. Particularly little is known about how to help college students with ASD obtain jobs.

OBJECTIVE: This study attempts to identify challenges with verbal communication during employment interviews that are specific to college students with ASD.

METHODS: We administered mock employment interviews to 16 college students with ASD and 14 college students without disabilities. Responses to interview questions were coded for content and timing.

RESULTS: Students with ASD …

Air- Sea Interactions And Ocean Dynamics In The Southwest Tropical Indian Ocean, Jessica Maureen Burns

Theses and Dissertations

The Southwest Tropical Indian Ocean (SWTIO) features a unique, seasonal upward lift of the thermocline, which is known as the Seychelles-Chagos Thermocline Ridge (SCTR; 55°E-65°E, 5°S-12°S). It is known that a high correlation exists between the depth of the thermocline and sea surface temperature (SST; a key ingredient for tropical cyclogenesis). With a particular focus on 2012/2013, this study reveals the dynamic properties of the SCTR that play an important role in the modulation of tropical cyclones in the SWTIO. Phenomena including Indian Ocean Dipole (IOD) and El Niño Southern Oscillation (ENSO) are also well correlated to cyclogenesis through changes …

Mismatch Tolerance During Homologous Recombination In Mammalian Cells, Shen Li

Theses and Dissertations

Homologous recombination (HR) serves critical roles in DNA repair to maintain genome stability, and the malfunction of HR contributes to carcinogenesis and cancer development. Current research focuses on the regulation against deleterious recombination between imperfectly matching sequences, which has been documented in certain myeloid leukemias, hereditary nonpolyposis colorectal cancers and other genetic diseases. Homology dependency of recombination was examined in cultured thymidine kinase-deficient mouse fibroblasts. Cells have chromosomal integration of DNA constructs harboring a herpes tk gene (the “recipient”) and a closely linked truncated “donor” tk sequence. The recipient was rendered non-functional by insertion of the recognition site for endonuclease …

The Influence Of Phytoplankton Size And Community Composition On Carbon Cycling And Planktonic Food Webs In The Sargasso Sea, Bridget Elise Cotti-Rausch

Theses and Dissertations

The Sargasso Sea is a dynamic physical environment located in the western North Atlantic where strong seasonal variability combines with forcing by mesoscale (~100 km) eddies. These drivers determine nutrient, light, and temperature regimes, and ultimate the size, composition and productivity of the phytoplankton community. My general objective was to determine how the structure and function of planktonic communities affected carbon export from the surface ocean in the Sargasso Sea. On four cruises (2011 and 2012; one eddy per cruise), I investigated links between water column structure, plankton community composition, size, and primary production (PP). I then combined PP data …

The Nutrition Assistance Landscape In Afterschool Programs: Understanding The Gap Between Research, Policy, And Practice, Falon Elizabet Tilley

Theses and Dissertations

The Child and Adult Care Food Program (CACFP) aims to increase children’s access to healthful foods in out-of-home care. Approximately half of the 10.2 million children enrolled in afterschool programs (ASPs) are eligible for nutrition assistance through programs like CACFP. Despite awareness of its potential impact on the nutritional status of millions of children, CACFP is underutilized among ASPs and notably understudied in comparison to other federal nutrition assistance programs.

This dissertation addresses key gaps in CACFP research and provides a deeper understanding of the nutrition assistance landscape in afterschool programs by (1) assessing the type of afterschool snacks served …

Molecular Exploration Of Bioavailable Dissolved Organic Matter Across Aquatic Ecosystems, Yuan Shen

Theses and Dissertations

Dissolved organic matter (DOM) in aquatic ecosystems is a large reservoir of reduced carbon that is mostly resistant to degradation. A small fraction of DOM cycles relatively quickly and is biologically utilized on timescales of days to months. This bioavailable DOM (BDOM) supports aquatic food webs, drives major elemental cycles, and is coupled to atmospheric CO2. Despite wide-ranging importance, bioavailability of DOM and its linkages to ecosystem properties (e.g., primary production, nutrients) are poorly characterized, particularly at the ecosystem level. Bioassay experiments are commonly used to determine BDOM, but this approach alters conditions and has limited spatial and temporal coverage. …