Accessibility & Glossary

EnviroDay 2025 Glossary

Session 1

Will Loner

• Defoliation: The physical degradation and consumption of leaf material by herbivores. Scale can vary from unnoticeable to the loss of entire canopies.

• Insect Outbreak: The phenomenon in which the population of certain species of insect significantly increases in density. This population “boom” can occur gradually in response to changing environmental conditions (gradient outbreak) or occur rapidly and spread from local epicenters to cover much larger areas (eruptive outbreaks). Outbreaks can occur irregularly, cyclically, or continuously.

• Landsat: A NASA program responsible for the acquisition of multispectral reflectance data from Earth’s surface between the wavelengths 435 nm and 12,5100 nm (11 bands). The instrument is sun-synchronous and achieves global coverage in 16 days, providing imagery at 15-60m resolution. Three Landsat instruments are currently active: Landsat 7 (1999-), Landsat 8 (2013-), and Landsat 9 (2021-).

• Moderate Resolution Imaging Spectroradiometer (MODIS): One of two satellite sensors (on the instruments Terra, 1999- and Aqua, 2002-) responsible for acquiring multispectral reflectance data from Earth’s surface between the wavelengths of 405 nm and 14,395 nm (36 bands). The instrument is sun-synchronous and achieves global coverage in 1-2 days, providing imagery at 250-1000m resolution.

• Nearest-Neighbor Imputation Approach: A method used to estimate missing or incomplete data based on existing, known data. In the case of USFS Tree Density Imputation Maps, forest inventory plots provide detailed, ground-level information on the presence and density of tree species at specific locations. Gridded satellite data offers broad spatial coverage of landscape features such as land cover type, elevation, and temperature. To assign a value to an unknown pixel, the nearest-neighbor imputation algorithm identifies nearby forest plots (with known species composition and densities) that are most similar to the environmental conditions of the unknown pixel. The unknown pixel is then assumed to have a similar species community and species density to those nearby plots, based on its environmental similarity.

• The Normalized Difference Vegetation Index (NDVI): A method of measuring greenness in a pixel. Calculated as the ratio of reflectance of near infrared light minus reflectance of red light to the total reflectance of near infrared and red light. Values range from -1 to 1, where the lowest (negative) values indicate clouds or water, positive values near 0 indicate bare ground, and the highest positive values indicate dense green vegetation.

• Piecewise Structural Equation Model (pSEM): A specific form of path analysis that simultaneously models relationships between multiple variables in a single causal network. pSEM is grounded in prior knowledge of the system, which informs hypotheses about the interactions among the constituent variables. This approach allows a variable to function as both a predictor and a response, enabling the examination of both direct and indirect effects within the system. Relationships are visually represented using path diagrams with arrows indicating the direction and type of assumed causal influence. These paths are then converted into a series of linear equations, which are evaluated individually. This process allows the model to handle non-normal data distributions, random effects, and autocorrelation.

• Polyphagy: The practice of being able to feed on more than one type of host. (adj. polyphagous).

• Random Forest Model: A machine learning algorithm that constructs a large number of decision trees during training, where each tree is trained on a random subset of the data using bootstrapping with replacement. Each tree makes its own prediction for an unknown pixel, and the final prediction for that pixel is derived by majority vote after aggregating the predictions of all trees. It is often employed in classification efforts.

• The Standardized Precipitation Evapotranspiration Index (SPEI): A method of measuring drought that incorporates both precipitation and temperature, the latter of which significantly influences evapotranspiration. This differential index determines whether the climate is wetter or drier than the historical average for a given location. Positive SPEI values indicate wetter-than-average conditions, while negative values indicate drier-than-average conditions. SPEI values below -0.5 indicate drought, and values below -2 generally signify severe drought. SPEI values are standardized to account for varying climatic conditions, allowing for meaningful comparisons between different regions and ecosystems.

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  Kelsey O’Donnell

• Drag: The amount of resistance to the flow an object imparts.

• Interstitial: The spaces between objects (e.g., spaces between mussels within a bed).

• Reynolds Stress: A measure of the strength of turbulent fluctuations.

• Shear Velocity: A measure of fluid movement due to shear forces (e.g., drag).

• Turbulence: Random fluctuations of fluid movement that cause mixing.

• Turbulent Kinetic Energy (TKE): A measure of the strength of turbulent forces, similar to Reynolds stress.

Session 2

Kylor Kerns

• Cumulative Heating: The total amount of heat stress the water experiences over time, relative to the heat threshold defined for seagrass. Above 28.6°C, seagrass stops capturing sunlight to make nutrients (photosynthesize), and the plant begins to stress, which can lead to die-off.

• Direct Contact: The disease spreads when infected leaves touch healthy ones.

• Leaf Morphology: The size and shape of seagrass leaves can affect how easily they get infected. If they are longer or larger, it could increase direct contact with other leaves.

• Marine Heatwave: A long period of hotter-than-normal ocean temperatures that can harm seagrass. Five or more days above the 90th percentile mean temperature for an area. Not specific to seagrass.

• Necrotic Lesions: Dark or dead spots on seagrass leaves caused by the disease.

• qPCR (Quantitative Polymerase Chain Reaction): A lab test that helps scientists measure how many diseased cells are in a seagrass sample.

• Seascape Connectivity: How different ocean areas (like seagrass meadows, marshes, and oyster reefs) are connected, which can affect the movement of water and nutrients. In this case, it could affect the movement of the disease.

• Severity: The area of diseased lesions divided by the area of the total leaf. A percentage.

• Standardized Coefficients: A way scientists compare different factors (like temperature or leaf size) to see which one affects the modeled relationship most.

• Temperature Anomalies: Unusually warm water temperatures that can stress seagrass. This includes Marine Heatwaves and Cumulative Heating.

• Wasting Disease / Labyrinthula zosterae (L. zosterae): A sickness that infects seagrass, especially Zostera marina, caused by tiny microbes (marine protist), which eat away at the leaves and make them weak.

• Water Residence Time: How long a parcel of water stays in one place before moving away, which affects how fast the disease spreads. If you think about tides, how quickly new water flushes in, stays, and then flushes out. Spots farther away from inlets or river mouths will have longer/higher residence times.

• Waterborne Transmission: The disease spreads through the water, moving from one plant to another.

Sophia Gibby

Using Blue Light Intensity to Uncover Climate-Growth Relationships in the Tree Ring Record of
Boreal Alaska
Advisors: Dr. Howard Epstein, Elise Heffernan

• Blue [Light] Intensity (BI): A method of measuring and quantifying the absorption of blue light by tracheids in each annual growth ring; blue intensity is correlated with UV light absorption in lignin, thus it is used to measure a tree’s response to temperature during the growing season.

• Boreal Forest: A largely coniferous forest growing in a high-latitude environment, characterized by freezing temperatures 6-8 months out of the year.

• Dendrochronology: The science of dating events, environmental change, and archaeological artifacts by using the patterns recorded in trees’ annual growth rings (“dendro” meaning tree, “chronology” meaning time).

• Detrend or Standardize: The method of fitting a curve to a raw ring-width distribution in order to remove long-term variations and isolate yearly to decadal growth trends (e.g., mean, two-thirds spline, negative exponential).

• Earlywood: The large xylem cells of annual growth rings produced in the early-to-mid growing season (light-colored, primary function: water transport).

• Latewood: The smaller xylem cells of annual growth rings produced later in the growing season, before annual dormancy (dark-colored, primary function: structural support).

• Latewood BI: The absorption of blue light by tracheids in latewood, specifically.

• Ring Width Index (RWI): An index for tree-ring width standardized to remove age-related growth trends (ring width for each year divided by its respective fitted growth curve value).

• Tracheids: The long, narrow cells that comprise annual growth rings in gymnosperms, also known as softwood trees or conifers.

• Tree-ring Chronology: The standardized collection of mean tree-ring series across one site (allows us to compare growth patterns between trees and sites independently of tree age and absolute growth rate).

• Tree-ring Series: The pattern of annual tree-ring widths within an individual tree.

Caroline Speidel

• iButtons: Small, button-shaped sensors used to track the temperature of a given location over time.

• RFID tags: Stands for Radio-Frequency IDentification tags. The tags are affixed to the backs of bumble bees and indicate when they enter or exit a colony using a scanner inserted at the entrance

Session 3

Hanne Borstlap

Surging Seas and Saline Soils: a Novel Approach to Modeling the Drivers and
Effects of Saltwater Intrusion

• ADCIRC: A large-scale computer model that simulates ocean movement and predicts how high storm surges will be during storms. The results are compared with tide gauge data to make sure they are accurate.

• Agricultural Ditches: Man-made channels in farm fields that help drain excess water and prevent crops from becoming waterlogged.

• RHESSys: An ecohydrologic model that tracks how water moves through the landscape, factoring in land use, soil type, and elevation. Here, it’s used to map soil moisture before a storm and to trace where saltwater goes after it infiltrates.

• Saltwater Infiltration: When storm surges push seawater onto land, the water can soak into the ground, given that there is space in the soil and it is not already fully saturated. This can harm crops and plants and make drinking water too salty for consumption.

Owen Shaffer

The Outsized Role of Vulnerable Wetlands in Nitrogen Cycling Across the
US in the Context of Changing Clean Water Act Protections

• 2015 CWR: In reference to the Clean Water Act, introduces the “significant nexus” test, which provides protection to wetlands with significant chemical or biological impact on a stream or river body.

• 2020 NWPR: Gets rid of the “significant nexus” test, limits wetland protection to wetlands with a surface connection to protected stream/river body, “navigable waters.”

• Hydrochemistry: A subdivision of hydrology that deals with the chemical characteristics of the water on and beneath the surface of the earth.

• Nitrogen Footprint: The amount of reactive nitrogen released to the environment as a result of an entity's resource consumption.

• Nitrogen Removal: Nitrogen (in the form of nitrate, etc.) removed from wetland systems through the process of denitrification and sedimentation. In effect, purifies downstream water bodies.

• Nitrogen Species: The different chemical compounds in which nitrogen can be assembled.

• TDN (Total Dissolved Nitrogen): The sum of dissolved inorganic nitrogen (NO₃⁻, NH₄⁺, etc.) and dissolved organic nitrogen

Emily Huber

• Fuzzy string matching: programming technique to find text that matches a patternapproximately

• SIMAP: SIMAP® (Sustainability Indicator Management & Analysis Platform) is a carbon and nitrogen-accounting platform that offers campuses a simple, comprehensive, and affordable online tool to track, analyze, and improve campus-wide sustainability.

• IEFT: Integrated Environmental Footprint Tool allows users to see how the carbon (C), nitrogen (N), phosphorus (P), and water (W) footprints at UVA change when campus consumption behaviors are changed.

• BAU: business as usual

Madeline Morphis

• Carbon Sequestration: How much carbon a tree or forest will take in and store annually, calculated for one year.

• Carbon Storage: How much carbon a tree or forest currently contains, for the lifetime of the tree or forest.

• Forest Succession: The process in which vegetation establishes and progresses over time, forming or transforming a forest.

• Hardwood Forest: A forest composed primarily of broadleaf species such as Oaks, Tulip Poplars, and Beech, not conifer trees like Pines.

• Hydrochemical Analysis: Analyzing the chemical composition of water to determine nitrogen concentrations, as well as other ions.

• Nitrogen Footprint: The amount of reactive nitrogen released to the environment as a result of an entity's resource consumption.

• Transect: A straight line on which observations are made.

Session 4

Paola Granados

• Flux: The rate at which mass moves through an environment; in this presentation, it is the rate at which concentration of a mass moves through a creek 
• Outwelling: Process where coastal ecosystems (e.g. salt marshes, mangroves) have such high productivity rates that they can export large amounts of organic matter/nutrients to a secondary ecosystem (e.g. coastal waters), contributing to the secondary ecosystem's productivity

Ethan Kadiyala

• Abundance: The total amount of a species in a given location (measured in density, total number, etc.).

• Period: The time it takes for a complete cycle, e.g., Earth's period around the sun is 365 days.

• Recruitment: Offspring joining a population and surviving to adulthood.

• Spatial Synchrony: Coincident changes in abundance across distant locations.

• Timescale: The period of a signal detected by our statistical tools.

Elaine Liu

• Alluvial fan: Depositional landforms that commonly occur at transitions from high-to-low slope, where there is a reduction in sediment transport capacity over a short distance.

• Apparent Oxygen Utilization (AOU): Measure of maximum possible dissolved oxygen at a given salinity and temperature minus the observed dissolved oxygen, where positive values indicate high respiration and consumption and negative values indicate high productivity.

• BAC (Bacterial Enumeration): A method to count or estimate the number of bacteria in a sample.

• Basin: Large low-lying area. In this case, a low-lying area that water flows into.

• BAU: Stands for business as usual. Represents UVA’s future nitrogen footprint assuming normal university growth and no additional operations changes.

• Benthic Microalgae: Photosynthetic microorganisms residing in sediment.

• Climate Feedback: A response of the climate system to warming that either intensifies (positive feedback) or dampens (negative feedback) warming. Main examples include water vapor, lapse rate, albedo, and cloud feedbacks.

• Cloud Optical Depth: A measure of the degree to which a cloud modifies light passing through it. This is dependent on cloud thickness, liquid and ice water content, and size distribution of ice crystals and water droplets. Different clouds are characterized by their optical depths and resulting differences in the ways they attenuate light.

• CMIP: Coupled Model Intercomparison Project. This is the framework through which climate modeling groups around the world collaborate and share climate model data. Common experiments and conventions allow for the comparison of results across models. Model ensembles are periodically updated, for example from CMIP5 to CMIP6, and coincide with the release of IPCC (Intergovernmental Panel on Climate Change) assessment reports.

• Coefficient of variance: A standardized measure of dispersion, the ratio of the standard deviation to the mean.

• Collinearity: Correlation between predictor variables.

• Cordilleran Ice Sheet (CIS): A now extinct ice sheet that covered the northwestern part of North America during the Last Glacial Maximum (20,000-14,000 years ago).

• CTX: Context Camera that provides high-resolution images created by NASA to gather planetary data.

• Emergent Constraint: [definition 1] A method used to constrain the variability of climate models’ predictions of warming using observations. This requires three components: 1) a statistical relationship between the intermodel variability in some climate variable and intermodel variability of climate sensitivity; 2) a plausible physical mechanism explaining the relationship between the climate variable and climate sensitivity; 3) observations of the climate variable that can be used to constrain variability of the variable in models and therefore the prediction of warming. [definition 2] Physically explainable empirical relationships between characteristics of the current climate and long-term climate prediction that emerge in collections of climate model simulations.

• Equilibrium Climate Sensitivity (ECS): The long-term increase of globally averaged surface temperature change a climate model predicts under a scenario of doubled CO2.

• Fluorescence: A two-step process in which a pigment first absorbs light of a relatively short wavelength and then emits light of a relatively long wavelength.

• Fluorescence yield: Ratio between fluorescence energy emitted by chlorophyll and light energy absorbed by chlorophyll.

• Gross primary productivity (GPP): The gross rate of CO2 uptake by plants.

• Grounded-ice margin: Where a glacier or ice sheet is last in contact with the ground beneath it. The position of this line is especially important for ice bodies that terminate into water.

• Harmonic Analysis: Method of studying periodic variations in time series using sine and cosine functions, where the harmonic increases indicate changes in frequencies.

• Hyperspectral imaging: A type of imaging that allows you to obtain the electromagnetic reflectance spectrum for each pixel of an image.

• ICP: Inductively coupled plasma mass spectrometry. The machine used to assess the levels of silver and copper in the water samples.

• Imaging spectroscopy: A synonym of hyperspectral imaging; a type of imaging that allows you to obtain the electromagnetic reflectance spectrum for each pixel of an image.

• ISCCP: International Satellite Cloud Climatology Project. Observations from this project output cloud coverage in cloud top pressure – optical depth space. An ISCCP simulator can also be deployed in climate models to produce analogous cloud fraction output that can be compared to ISCCP observational data.

• Last Glacial Maximum (LGM): The global period in which ice sheets were last at their maximum extent (around 20,000 years ago).

• Light use efficiency: The ratio between GPP and light energy absorbed by plants.

• Marine-terminating ice sheet: A large, persistent body of ice overlying an entire body of land that directly contributes to and is in contact with the ocean.

• Morphometry: Measuring the external shape and dimensions of landforms.

• Nitrogen Footprint: The amount of reactive nitrogen released to the environment as a result of an entity’s resource consumption.

• Paleoclimate: Climate during a particular time in the geological past.

• Percent cover: The percent of the canopy that is made up by each species present in the area; can add up to more than 100% when adding all the species due to overlap and multiple canopy layers.

• Permafrost: Ground that remains continuously frozen for longer than two years.

• Phenology: The study of the timing of cyclic, often seasonally recurring, natural phenomenon, such as the shedding of leaves by deciduous trees in autumn.

• POC (Particulate Organic Carbon): A measure of carbon in particulate organic matter.

• PON (Particulate Organic Nitrogen): A measure of nitrogen in particulate organic matter.

• POP (Particulate Organic Phosphorous): A measure of phosphorous in particulate organic matter.

• Point-of-use water filters: Rather than serving as a filtration system for an entire water supply, point-of-use water filters directly purify water as it is about to be used in smaller quantities. This form of water treatment is more feasible in a rural, developing context.

• Radiative Kernels: A method for calculating and decomposing the top-of-atmosphere radiative flux changes that result from feedbacks in a warming atmosphere. Kernels are typically multiplied by the change of the variable of interest, such as change in cloud fraction from a control state to a warmed state, to yield a change in radiative flux resulting from the feedback in question.

• Red edge: A region in the electromagnetic spectrum between red and the near-infrared wavelengths, which is typically associated with a steep increase in reflectance in healthy vegetation.

• Remote Sensing: [definition 1] The process of monitoring or determining the physical characteristics of materials by measuring its reflected or emitted radiation from a distance. [definition 2] Acquisition of information about an object or phenomenon without making physical contact with the object, in contrast to in situ or on-site observation.

• Rossby wave: A large, slow-moving, planetary-scale wave generated in the troposphere by ocean-land temperature contrasts and topographic forcing (winds flowing over mountains), and affected by the Coriolis effect due to the earth’s rotation.

• Seed bank: Repository of seeds within the soil; seeds can remain there for many years before germinating, which is often triggered by environmental conditions.

• Solar-Induced Fluorescence (SIF): [definition 1] Light emitted by chlorophyll in the red to near-infrared wavelengths following light absorption. Commonly abbreviated as SIF. [definition 2] Faint light emitted by chlorophyll when it absorbs sunlight.

• Spatial resolution: The spatial sensitivity of a sensor; typically described as the size of a single pixel.

• Spectral bands: The recorded wavelengths by a sensor.

• Spectral resolution: The spectral sensitivity of a sensor; in hyperspectral imaging, the sensor is not sensitive to all wavelengths of the electromagnetic spectrum but rather records information every few wavelengths.

• Spectral signature: Variation of reflectance or emittance of a material with respect to wavelengths.

• Subtropical jet: A belt of strong upper-level winds lying above regions of subtropical high pressure.

• TOC (Total Organic Carbon): A measure of all carbon in organic compounds in a sample.

• TON (Total Organic Nitrogen): A measure of all nitrogen in organic compounds in a sample.

• TOP (Total Organic Phosphorous): A measure of all phosphorous in organic compounds in a sample.

• Topography: The changes in elevation over a particular area.

• Walker Circulation: Longitudinal (east-west) circulation across the equatorial Pacific.

Posters

Wayne Dawson

• Anthropogenic Climate Change: Shifts in regional patterns of temperature, precipitation, and other weather-related processes resulting from human-driven emissions of greenhouse gases, generally manifesting as a warming and drying effect in the arctic.

• Chlorophyll Fluorescence: The emission of light energy absorbed by chlorophyll as light. This process competes with photosynthesis and heat dissipation for absorbed light energy and thus can be monitored to understand photosynthetic physiology. Referred to as solar-induced fluorescence (SIF) when the absorbed energy originates from sunlight.

• Growing Degree Days (GDD): A metric used to capture how the temperature experienced by a plant accumulates over the year, usually to relate seasonal temperature patterns to phenological events such as the timing of when deciduous plants grow new leaves. Calculated as: GDD = Tday - Tbase, where Tday is the daily average temperature and Tbase is an arbitrarily chosen base temperature. Positive values from each successive day in the year are summed together to capture how temperatures have accumulated over the year.

• Heat Dissipation or Heat Loss: The release of light energy absorbed by chlorophyll as heat. This process competes with photosynthesis and fluorescence for absorbed light energy and functions like sunscreen, protecting the plant from excessively high light levels by safely releasing it as heat. Also known as non-photochemical quenching (NPQ).

• Phenology: The timing of a natural process or event. Often used in the context of seasonally-repeating processes like plant flowering or animal migrations.

• Photosynthesis: The usage of light energy absorbed by chlorophyll to fix carbon dioxide (CO2) into sugars. This process competes with heat dissipation and fluorescence for absorbed light energy.

Physiology: The functioning of an organism, organ, or process.

Preston Thompson

• CTmax (Critical Thermal Maximum): The highest temperature at which an organism can survive.
• 2. Brood: The offspring or young bumble bees, including larvae and pupae.
• 3. Fanning: A behavior in which bumble bees use their wings to create airflow and cool
• their nest and brood.
• 4. Active Thermoregulation: This involves behaviors and physiological processes that an organism actively engages in to control its body temperature. For bumble bees, active thermoregulation includes behaviors like fanning their wings to cool the nest or shivering to generate heat.
• 5. Passive Thermoregulation: This refers to the natural, non-behavioral methods by which an organism maintains its body temperature. For bumble bees, passive thermoregulation might include choosing nesting sites that naturally provide insulation from temperature extremes, such as underground burrows or shaded areas.

Misc.

Ecological Terms

• Abundance: The total number of individuals within a species in a given area.

• Aquatic macroinvertebrate: Small animals that live for most or all of their lives in the water.

• Benthic: Relating to the bottom of a body of water.

• Epifauna: Animals living on the surface of the seabed or riverbed.

• Infauna: Animals living in the sediment of a sea floor, river bed, etc.

• Species richness: The number of different species in a given area.

• Taxa: The hierarchical divisions of a species from kingdom to subspecies (the different ways to categorize an organism).