Biology Commons^™

Synchronization Of Reproduction In Deertoe Mussel (Truncilla Truncata), Kendell R. Loyd

Graduate Theses/Dissertations

Freshwater mussels, Order Unionoida, are diverse and widespread in North America but have suffered general decline and many extinctions in recent decades. The reproductive biology of Unionoida is complex and may be vulnerable to human impacts. Male mussels release aggregates of sperm called spermatozeugmata that drift downstream. Females obtain spermatozeugmata from the water and brood the fertilized eggs internally during development. Many aspects of general reproductive biology are poorly understood, including the mechanisms that coordinate spawning and the route by which sperm meet eggs in the female. The present study focuses on reproduction in the Deertoe (Truncilla truncata), …

Evaluating The Relationship Of Temperature And Growth Of A Larval Colorado River Catostomid, C. Latipinnis, Through Otolith Aging And Stable Isotopes (Δ18o), Adam Lawrence Barkalow

Biology ETDs

Knowledge of early life history strategies and ecological dynamics of larval fish growth and development is invaluable for effectively managing and conserving common and endangered fish species. Isotopic analysis of otoliths (bony structures of the inner ear) from larval Flannelmouth Suckers Catostomus latipinnis obtained from the Colorado River in Grand Canyon could greatly facilitate understanding of thermally-regulated growth rates, thermal preferences, and ontogenetic habitat use by these fishes. Colorado River water temperatures in the Grand Canyon are highly modified from projected historic water temperatures present before closure Glen Canyon Dam. Cold water as result of Glen Canyon dam and hypolimnetic …

Multiple Opening Closing Net Environmental Sensing System (Mocness) Instrument Data For Cruise Dp05 R/V Point Sur In-Situ Deep Seawater And Associated Fauna, May 1-11, 2017, Viosca Knoll Gom, Gray Lawson, Travis Richards

DEEPEND Datasets

The Multiple Opening Closing Net and Environmental Sensing System(s) (MOCNESS) deployed during the DEEPEND field program collects data (e.g., pressure, temperature, conductivity, volume filtered, horizontal and vertical velocity, latitude, and longitude) from several sensors while the instrument is in use. These data help characterize the environment and assess the orientation and speed of the MOCNESS. The flow and net angle can be used to calculate the volume of water filtered for each net. The biological data and ship data collected during this cruise are available in GRIIDC datasets R4.x257.226:0005 and R4.x257.226:0014 respectively.

Interacting Stressors And The Potential For Adaptation In A Changing World: Responses Of Populations And Individuals, Gareth R. Hopkins, Susannah S. French, Edmund D. Brodie Jr.

Biology Faculty Publications

To accurately predict the impact of environmental change, it is necessary to assay effects of key interacting stressors on vulnerable organisms, and the potential resiliency of their populations. Yet, for the most part, these critical data are missing. We examined the effects of two common abiotic stressors predicted to interact with climate change, salinity and temperature, on the embryonic survival and development of a model freshwater vertebrate, the rough-skinned newt (Taricha granulosa) from different populations. We found that salinity and temperature significantly interacted to affect newt embryonic survival and development, with the negative effects of salinity most pronounced …

Reduced Mitochondrial Efficiency Explains Mismatched Growth And Metabolic Rate At Supraoptimal Temperatures., Eloy Martinez, Michael A. Menze, Salvatore J. Agosta

Faculty and Staff Scholarship

The relationship between whole-organism growth and metabolism is generally assumed to be positive and causative; higher metabolic rates support higher growth rates. In Manduca sexta, existing data demonstrate a deviation from this simple prediction: at supraoptimal temperatures for larval growth, metabolic rate keeps increasing while growth rate is decreasing. This mismatch presumably reflects the rising “cost of maintenance” with temperature. Precisely what constitutes this cost is not clear, but we suspect the efficiency with which mitochondria harness oxygen and organic substrates into cellular energy (ATP) is key. We tested this by integrating existing data on M. sexta growth and …

The Effect Of Cold On The Physiology Of Drosophila Larva Heart And On Synaptic Transmission At Crayfish Neuromuscular Junctions, Yuechen Zhu

Theses and Dissertations--Biology

Ectothermic animals are susceptible to temperature changes such as cold shock with seasons. To survive through a cold shock, ectotherms have developed unique strategies. My interest is focusing on the physiological function of during cold shock and prolonged cold exposure in the fruit fly (Drosophila melanogaster) and crayfish (Procambarus clarkii). I used Drosophila melanogaster as a model system to investigate cardiac function in response to modulators (serotonin, acetylcholine, octopamine, dopamine and a cocktail of modulators) in acute cold shock and chronic cold shock conditions as possible mechanism to regulate heart rate in the cold. To examine if the dampened heart …

The Biological Stress Response In Bluegill Sunfish (Lepomis Macrochirus) To Variations In Environmental Temperature And Dissolved Oxygen Content., Monique Kellman

Honors College Theses

With the predicted increase in global water temperature and acute hypoxic episodes, knowledge of the effects these stressors can have on local aquatic life is extremely valuable. This study thereby quantified the change in metabolic rate in Bluegill sunfish, in response to increased temperature and low dissolved oxygen concentration, by utilizing intermittent flow respirometry. Both maximum metabolic rate (MMR) and resting metabolic rate (RMR) were determined in response to variations in dissolved oxygen content, specifically > 95% O₂ and 40% O₂. Additionally, three temperature treatment groups were established, with temperatures of 20, 25 and 30°C in order to …

Examining The Combined Effects Of Dissolved Oxygen, Temperature, And Body Size On The Physiological Responses Of A Model Macrobenthic Polychaete Species, Capitella Teleta, Kelsey Burns Gillam

Dissertations

While the scientific community is in consensus that coastal systems are threatened by climate change, few climate change studies test the effects of more than one variable directly related to climate change. The dissolved oxygen (DO) levels of the ocean are currently subject to both global warming and eutrophication; 94% of all hypoxia zones are expected to experience >2°C increase by 2035. This dissertation aims to examine how a model organism responds to simultaneous thermal and DO stress involving four levels of DO (100%, 70%, 50%, and 20%) saturation and three temperatures (15°C, 20°C, and 25°C).

The polychaete, Capitella teleta …

Phytochrome B Integrates Light And Temperature Signals In Arabidopsis, Martina Legris, Cornelia Klose, E Sethe Burgie, Cecilia Costigliolo Rojas Rojas, Maximiliano Neme, Andreas Hiltbrunner, Philip A. Wigge, Eberhard Schäfer, Richard D. Vierstra, Jorge J. Casal

Biology Faculty Research

Ambient temperature regulates many aspects of plant growth and development, but its sensors are unknown. Here, we demonstrate that the phytochrome B (phyB) photoreceptor participates in temperature perception through its temperature-dependent reversion from the active Pfr state to the inactive Pr state. Increased rates of thermal reversion upon exposing Arabidopsis seedlings to warm environments reduce both the abundance of the biologically active Pfr-Pfr dimer pool of phyB and the size of the associated nuclear bodies, even in daylight. Mathematical analysis of stem growth for seedlings expressing wild-type phyB or thermally stable variants under various combinations of light and temperature revealed …

Commentary: The Spinal Cord Has An Intrinsic System For The Control Of Ph, Joseph M. Santin, Tobias Wang, Saihari S. Dukkipati, Lynn K. Hartzler

Biological Sciences Faculty Publications

Most physiological processes are sensitive to pH (i.e., hydrogen ion activity) and regulation of pH within tissues and body fluids represents a fundamental homeostatic process in living organisms. At the organismal level, acid-base balance is achieved by fast respiratory modulations of the partial pressure of CO2 in combination with slower transepithelial ion movements to accommodate excretion and retention of bicarbonate and protons in response to acid-base disturbances. At the cellular and subcellular levels, acid-base balance is achieved by ion exchange.

The Variation Of Productivity And Its Allocation Along A Tropical Elevation Gradient: A Whole Carbon Budget Perspective, Yadvinder Malhi, Cécile A. J. Girardin, Gregory R. Goldsmith, Christopher E. Doughty, Norma Salinas, Daniel B. Metcalfe, Walter Huaraca Huasco, Javier E. Silva-Espejo, Jhon Del Aguilla-Pasquell, Filio Farfán Amézquita, Luiz E.O.C. Aragão, Rossella Guerrieri, Françoise Yoko Ishida, Nur Bahar, William Farfan-Rios, Oliver L. Phillips, Patrick Meir, Miles Silman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

• Why do forest productivity and biomass decline with elevation? To address this question, research to date generally has focused on correlative approaches describing changes in woody growth and biomass with elevation.
  
  
• We present a novel, mechanistic approach to this question by quantifying the autotrophic carbon budget in 16 forest plots along a 3300 m elevation transect in Peru.
  
  
• Low growth rates at high elevations appear primarily driven by low gross primary productivity (GPP), with little shift in either carbon use efficiency (CUE) or allocation of net primary productivity (NPP) between wood, fine roots and canopy. The lack of trend in …

Paradoxical Acclimation Responses In The Thermal Performance Of Insect Immunity., Laura V Ferguson, David E Heinrichs, Brent J Sinclair

Biology Publications

Winter is accompanied by multiple stressors, and the interactions between cold and pathogen stress potentially determine the overwintering success of insects. Thus, it is necessary to explore the thermal performance of the insect immune system. We cold-acclimated spring field crickets, Gryllus veletis, to 6 °C for 7 days and measured the thermal performance of potential (lysozyme and phenoloxidase activity) and realised (bacterial clearance and melanisation) immune responses. Cold acclimation decreased the critical thermal minimum from -0.5 ± 0.25 to -2.1 ± 0.18 °C, and chill coma recovery time after 72 h at -2 °C from 16.8 ± 4.9 to 5.2 …

Depression In Thermal Performance Of Age-Structured Spirodela Polyrhiza Due To The Presence Of Rhopalosiphum Nymphaeae, Mitchell Matis, Chad Brassil, Colby J. Tanner

UCARE: Research Products

Thermal performance curves are keys components of population ecology. We performed this study to determine the effects of aphids on duckweed age-structured models across temperature. Results show a depression in birth rates and maturation of rates of duckweed in the presence of aphids. Regression analysis shows that this depression in maturation and birth is directly proportional to aphid growth rates across temperatures. This hints of the idea of modeling duckweed and aphid growth via nested thermal performance curves.

Damsels In Distress: A Study Of The Effect Of Temperature On Damselfly Competitive Interactions, Madison Pitts

Biological Sciences Undergraduate Honors Theses

Temperature has a fundamental role in shaping numerous physiological aspects of organisms, such as growth rate, that determine an organism's performance. Due to global climate change, temperature is projected to keep increasing. As temperature increases, so does an organism’s growth rate. Also, as competition increases organisms’ growth rate decreases. While studies have examined these factors individually, no experiments have assessed the combined impact of temperature and competition on organism’s growth rates. The experiment we conducted manipulated temperature and density in order to project what will happen as a result of rising temperatures.

Dynamics And Thermal Sensitivity Of Ballistic And Non-Ballistic Feeding In Salamanders, Stephen M, Deban, Jeffrey A. Scales

Integrative Biology Faculty and Staff Publications

Low temperature reduces the performance of muscle-powered movements, but in movements powered by elastic recoil mechanisms, this effect can be mitigated and performance can be increased. To better understand the morphological basis of high performance and thermal robustness of elastically powered movements, we compared feeding dynamics at a range of temperatures (5-25°C) in two species of terrestrial plethodontid salamanders, Plethodon metcalfi and Ensatina eschscholtzii, which differ in tongue muscle architecture and the mechanism of tongue projection. We found that Ensatina is capable of ballistic projection with a mean muscle mass-specific power of 2100 W kg(-1), revealing an elastic mechanism. Plethodon, …

Optogenetic Stimulation Of Drosophila Heart Rate At Different Temperatures And Ca2+ Concentrations, Yuechen Zhu, Henry Uradu, Zana R. Majeed, Robin L. Cooper

Biology Faculty Publications

Optogenetics is a revolutionary technique that enables noninvasive activation of electrically excitable cells. In mammals, heart rate has traditionally been modulated with pharmacological agents or direct stimulation of cardiac tissue with electrodes. However, implanted wires have been known to cause physical damage and damage from electrical currents. Here, we describe a proof of concept to optically drive cardiac function in a model organism, Drosophila melanogaster. We expressed the light sensitive channelrhodopsin protein ChR2.XXL in larval Drosophila hearts and examined light‐induced activation of cardiac tissue. After demonstrating optical stimulation of larval heart rate, the approach was tested at low temperature …

Similar Metabolic Rate-Temperature Relationships After Acclimation At Constant And Fluctuating Temperatures In Caterpillars Of A Sub-Antarctic Moth., Steven L Chown, Tanya M Haupt, Brent J Sinclair

Biology Publications

Temperature compensation in whole-animal metabolic rate is one of the responses thought, controversially, to characterize insects from low temperature environments. Temperature compensation may either involve a change in absolute values of metabolic rates or a change in the slope of the metabolic rate - temperature relationship. Moreover, assessments of compensation may be complicated by animal responses to fluctuating temperatures. Here we examined whole animal metabolic rates, at 0 °C, 5 °C, 10 °C and 15 °C, in caterpillars of the sub-Antarctic moth, Pringleophaga marioni Viette (Tineidae), following one week acclimations to 5 °C, 10 °C and 15 °C, and fluctuating …

Human Gut Bacteria Are Sensitive To Melatonin And Express Endogenous Circadian Rhythmicity, Jiffin K. Paulose, John M. Wright, Akruti G. Patel, Vincent M. Cassone

Biology Faculty Publications

Circadian rhythms are fundamental properties of most eukaryotes, but evidence of biological clocks that drive these rhythms in prokaryotes has been restricted to Cyanobacteria. In vertebrates, the gastrointestinal system expresses circadian patterns of gene expression, motility and secretion in vivo and in vitro, and recent studies suggest that the enteric microbiome is regulated by the host’s circadian clock. However, it is not clear how the host’s clock regulates the microbiome. Here, we demonstrate at least one species of commensal bacterium from the human gastrointestinal system, Enterobacter aerogenes, is sensitive to the neurohormone melatonin, which is secreted into the …

Abiotic And Biotic Factors Influence Refuge Use At The Community And Organismal Level, George Todd

College of Graduate Studies: Theses & Dissertations

Animal behavior is influence by a wide range of factors. One factor that can heavily influence behavior is the presence or absence of refuge (i.e., refuge provides a direct benefit to animals’ fitness). Many animals seek refuge to avoid predation despite clear costs to other life processes. The decision to use refuge is complex and anthropogenic activities may alter the abundance of refuge. Artificial refuge structures can be successful in conservation efforts and are an effective means to measure biodiversity. Thus, I used cover boards to examine how habitat structure and season influence vertebrate abundance and diversity in the southeastern …

Seed Germination Ecology Of The Cold Desert Annual Isatis Violascens (Brassicaceae): Two Levels Of Physiological Dormancy And Role Of The Pericarp, Yuan M. Zhou, Juan J. Lu, Dun Y. Tan, Carol C. Baskin, Jerry M. Baskin

Biology Faculty Publications

The occurrence of various species of Brassicaceae with indehiscent fruits in the cold deserts of NW China suggests that there are adaptive advantages of this trait. We hypothesized that the pericarp of the single-seeded silicles of Isatis violascens restricts embryo expansion and thus prevents germination for 1 or more years. Thus, our aim was to investigate the role of the pericarp in seed dormancy and germination of this species. The effects of afterripening, treatment with gibberellic acid (GA₃) and cold stratification on seed dormancy-break were tested using intact silicles and isolated seeds, and germination phenology was monitored in …

Tradeoffs Of Warm Adaptation In Aquatic Ectotherms: Live Fast, Die Young?, A. P. Porreca, E. Martinez, R. E. Colombo, Michael A. Menze

Faculty Research & Creative Activity

In the face of a changing climate, questions regarding sub-lethal effects of elevated habitat temperature on the physiology of ectotherms remain unanswered. In particular, long-term responses of ectotherms to the warming trend in tropical regions are unknown and significantly understudied due primarily to the difficulties in specimen and community traceability. In freshwater lakes employed as cooling reservoirs for power plants, increased physiological stress from high water temperature can lead to an increase in mortality, reduce growth, and potentially alter the community structure of fishes. Throughout this study, we employ this highly tractable system to assess how elevated thermal regimes can …

Tradeoffs Of Warm Adaptation In Aquatic Ectotherms : Live Fast, Die Young?, A. Porreca, E. Martinez, R. Colombo, Michael Menze

Faculty and Staff Scholarship

In the face of a changing climate, questions regarding sub-lethal effects of elevated habitat temperature on the physiology of ectotherms remain unanswered. In particular, long-term responses of ectotherms to the warming trend in tropical regions are unknown and significantly understudied due primarily to the difficulties in specimen and community traceability. In freshwater lakes employed as cooling reservoirs for power plants, increased physiological stress from high water temperature can lead to an increase in mortality, reduce growth, and potentially alter the community structure of fishes. Throughout this study, we employ this highly tractable system to assess how elevated thermal regimes can …

Physiological Performance Of Warm-Adapted Marine Ectotherms : Thermal Limits Of Mitochondrial Energy Transduction Efficiency., Eloy Martinez, Eric Hendricks, Michael Menze, Joseph Torres

Faculty and Staff Scholarship

Thermal regimes in aquatic systems have profound implications for the physiology of ectotherms. In particular, the effect of elevated temperatures on mitochondrial energy transduction (i.e. energy from carbon substrates to ATP) in tropical and subtropical teleosts may have profound consequences on organismal performance and population viability. Upper and lower whole-organism critical temperatures for teleosts suggest that subtropical and tropical species are not susceptible to the warming trends associated with climate change, but sub-lethal effects on energy transduction efficiency and population dynamics remain unclear. The goal of the present study was to compare the thermal sensitivity of processes associated with mitochondrial …

Morphometry And Average Temperature Affect Lake Stratification Responses To Climate Change, Benjamin Kraemer, Orlane Anneville, Sudeep Chandra, Margaret Dix, Esko Kuusisto, David M. Livingstone, Alon Rimmer, S. Geoffrey Schladow, Eugene Silow, Lewis M. Sitoki, Rashid Tamatamah, Yvonne Vadeboncoeur, Peter B. Mcintyre

Biological Sciences Faculty Publications

Climate change is affecting lake stratification with consequences for water quality and the benefits that lakes provide to society. Here we use long-term temperature data (1970–2010) from 26 lakes around the world to show that climate change has altered lake stratification globally and that the magnitudes of lake stratification changes are primarily controlled by lake morphometry (mean depth, surface area, and volume) and mean lake temperature. Deep lakes and lakes with high average temperatures have experienced the largest changes in lake stratification even though their surface temperatures tend to be warming more slowly. These results confirm that the nonlinear relationship …

Mathematical Model: Comparative Study Of Thermal Effects Of Laser In Corneal Refractive Surgeries, Gokul Kc, Dil B. Gurung, Pushpa R. Adhikary

Applications and Applied Mathematics: An International Journal (AAM)

Lasers have been widely used in ophthalmology. Refractive errors are some of the most common ophthalmic abnormalities worldwide. Laser refractive surgery was developed to correct refractive errors myopia, hyperopia and astigmatism. Two types of laser surgical techniques: lamellar and thermal are available to reshape the corneal curvature. Ultraviolet (UV) emitting argon fluoride (ArF) excimer laser is used to sculpt cornea in lamellar procedures, whereas, infrared (IR) emitting holmium yttrium aluminum garnet (Ho: YAG) laser is used to shrink cornea in thermal procedure. Tissue heating is common in all types of laser surgical techniques. Hence, in this paper, a finite element …

Allelic Polymorphism Of Gigantea Is Responsible For Naturally Occurring Variation In Circadian Period In Brassica Rapa, Qiguang Xie, Ping Lou, Victor Hermand, Rashid Aman

Dartmouth Scholarship

GIGANTEA (GI) was originally identified by a late-flowering mutant in Arabidopsis, but subsequently has been shown to act in circadian period determination, light inhibition of hypocotyl elongation, and responses to multiple abiotic stresses, including tolerance to high salt and cold (freezing) temperature. Genetic mapping and analysis of families of heterogeneous inbred lines showed that natural variation in GI is responsible for a major quantitative trait locus in circadian period in Brassica rapa. We confirmed this conclusion by transgenic rescue of an Arabidopsis gi-201 loss of function mutant. The two B. rapa GI alleles each fully rescued the …

Insects In Fluctuating Thermal Environments., Hervé Colinet, Brent J Sinclair, Philippe Vernon, David Renault

Biology Publications

All climate change scenarios predict an increase in both global temperature means and the magnitude of seasonal and diel temperature variation. The nonlinear relationship between temperature and biological processes means that fluctuating temperatures lead to physiological, life history, and ecological consequences for ectothermic insects that diverge from those predicted from constant temperatures. Fluctuating temperatures that remain within permissive temperature ranges generally improve performance. By contrast, those which extend to stressful temperatures may have either positive impacts, allowing repair of damage accrued during exposure to thermal extremes, or negative impacts from cumulative damage during successive exposures. We discuss the mechanisms underlying …

Climate Change Enhances The Negative Effects Of Predation Risk On An Intermediate Consumer, Luke P. Miller, Catherine M. Matassa, Geoffrey C. Trussell

Faculty Publications, Biological Sciences

Predators are a major source of stress in natural systems because their prey must balance the benefits of feeding with the risk of being eaten. Although this 'fear' of being eaten often drives the organization and dynamics of many natural systems, we know little about how such risk effects will be altered by climate change. Here, we examined the interactive consequences of predator avoidance and projected climate warming in a three-level rocky intertidal food chain. We found that both predation risk and increased air and sea temperatures suppressed the foraging of prey in the middle trophic level, suggesting that warming …

Salinity And Temperature Distribution Of Jellyfish In The San Francisco Estuary, Trisha Huynh, Brooke Bemowski, Lindsay Sullivan, Wim Kimmerer

STAR Program Research Presentations

Jellyfish are generally characterized by their jelly-like bodies and internal lining (two tissue layers). They found both in the phylum Ctenophora and the phylum Cnidaria. Ctenophores differ from cnidarians primarily due to the rows of “combs”, or cilia, which are used for transportation. Additionally, ctenophores possess sticky cells while cindarians possess stinging cells. Jellyfish depend on zooplankton (small floating aquatic animals) as a food source; as a result, they are potential competitors and predators to plankton-eating fish and may negatively impact fish populations.

As recently as 1950, jellyfish have entered the San Francisco Bay from the Mediterranean Sea (probably …

Temperature Alters Food Web Body-Size Structure, Jean P. Gibert, John P. Delong

School of Biological Sciences: Faculty Publications

The increased temperature associated with climate change may have important effects on body size and predator– prey interactions. The consequences of these effects for food web structure are unclear because the relationships between temperature and aspects of food web structure such as predator–prey body-size relationships are unknown. Here, we use the largest reported dataset for marine predator–prey interactions to assess how temperature affects predator–prey body-size relationships among different habitats ranging from the tropics to the poles. We found that prey size selection depends on predator body size, temperature and the interaction between the two. Our results indicate that (i) predator–prey …