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OpenStem
@openstem · Joined Jul 2026
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Flashcards8 cards
What is a species distribution model (SDM), and what does it output?1 / 8
An SDM statistically relates a species' known occurrence records to a set of environmental predictor layers (temperature, precipitation, elevation, land cover) to estimate the species' environmental suitability across a landscape. Its output is typically a continuous suitability surface (0 to 1) that can be thresholded into a binary predicted presence/absence map, used for conservation planning, invasive-species risk mapping, or climate-change range forecasting.
Environmental · L5 · Species Distribution Modeling & Niche Theory
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Environmental · L5 · Species Distribution Modeling & Niche TheoryFlashcards8 cards
What is a chemical transport model (CTM), and what three physical processes does it couple within each grid cell?1 / 8
A CTM is a numerical model that simulates how air pollutant concentrations evolve in space and time by solving the atmospheric species continuity equation on a 3D grid. It couples: (1) advection/transport by resolved winds, (2) turbulent mixing (vertical diffusion, often within a boundary-layer scheme), and (3) chemical transformation (gas-phase and sometimes aerosol reactions) — each grid cell's concentration changes from all three simultaneously.
Environmental · L5 · Atmospheric Chemistry & Chemical Transport Modeling
@openstem
Environmental · L5 · Atmospheric Chemistry & Chemical Transport ModelingFlashcards8 cards
Write the general advection-diffusion equation for a dissolved/dispersed contaminant concentration C in a moving fluid.1 / 8
The concentration's rate of change plus advective transport by the mean velocity field u equals turbulent/molecular diffusion (Fickian, with diffusivity D) plus any source term S. Environmental fluid mechanics applies this same governing equation to pollutant plumes in air, dye in a river, or a contaminant in groundwater — only the geometry, velocity field, and diffusivity differ.
Environmental · L5 · Environmental Fluid Mechanics: Turbulent Dispersion & Plume Modeling
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Environmental · L5 · Environmental Fluid Mechanics: Turbulent Dispersion & Plume ModelingFlashcards8 cards
What is a community (Jacobian) matrix in food web analysis, and what does each entry represent?1 / 8
The community matrix A linearizes a multi-species interaction system around an equilibrium: entry a_ij is the effect of a small change in species j's abundance on species i's per-capita growth rate, evaluated at equilibrium (essentially ∂(dN_i/dt)/∂N_j). Its sign pattern encodes the interaction type between each species pair — negative/positive for predator-prey, negative/negative for competition, positive/positive for mutualism — and its eigenvalues determine whether the equilibrium is locally stable.
Environmental · L5 · Ecological Network Analysis & Food Web Stability
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Environmental · L5 · Ecological Network Analysis & Food Web StabilityFlashcards8 cards
Contrast a cohort study with a case-control study, and state the key design trade-off between them for studying an environmental exposure.1 / 8
A cohort study follows a group defined by exposure status forward in time to compare disease incidence between exposed and unexposed groups — it can estimate incidence and relative risk directly, and exposure is measured before disease onset (reducing recall bias), but it's slow and expensive, especially for rare outcomes. A case-control study instead starts with cases (people who already have the disease) and matched controls, then looks BACKWARD at exposure history — much faster and cheaper for rare diseases, but exposure is reconstructed retrospectively, which is especially vulnerable to recall bias and reverse-causation concerns for environmental exposures that are hard to measure historically.
Environmental · L5 · Environmental Epidemiology: Study Design & Causal Inference
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Environmental · L5 · Environmental Epidemiology: Study Design & Causal InferenceFlashcards8 cards
State Darcy's law for groundwater flow, and explain what hydraulic conductivity K represents.1 / 8
Darcy's law says the specific discharge (Darcy flux) q through a porous medium is proportional to the negative hydraulic head gradient dh/dl — water flows from high head to low head. K, hydraulic conductivity, is an empirical property of both the medium (grain size, porosity, pore connectivity) AND the fluid (viscosity, density) that sets how readily water moves through it — gravel might have K many orders of magnitude larger than clay.
Environmental · L5 · Groundwater Flow & Contaminant Transport Modeling
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Environmental · L5 · Groundwater Flow & Contaminant Transport ModelingFlashcards8 cards
Name the three major sources of uncertainty in a climate projection, and briefly distinguish them.1 / 8
1) Scenario uncertainty — we don't know future greenhouse gas emissions/socioeconomic pathways, so projections are conditional on assumed scenarios (e.g. SSP2-4.5, SSP5-8.5), not unconditional forecasts. 2) Model (structural/response) uncertainty — different climate models, even under the identical scenario, disagree because they encode different physical parameterizations (clouds, ocean mixing). 3) Internal variability — the climate system's own chaotic, unforced fluctuations (like ENSO) mean even a single model run under a fixed scenario would differ from another run with slightly different initial conditions. All three add uncertainty, but their RELATIVE importance shifts with projection horizon.
Environmental · L5 · Climate Model Uncertainty Quantification & Bayesian Calibration
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Environmental · L5 · Climate Model Uncertainty Quantification & Bayesian CalibrationQuiz2 questions
Where does rain come from?
AFrom rivers flying upwardBFrom water drops in cloudsCFrom the ocean directlyDFrom the ground
Environmental · L1 · Weather and Rocks
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Environmental · L1 · Weather and RocksQuiz4 questions
What is magma?
AFrozen water found in glaciersBMelted rock found beneath Earth's surfaceCA type of soil rich in mineralsDGas in the atmosphere
Environmental · L1 · Volcanoes, Soil, and Fresh Water
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Environmental · L1 · Volcanoes, Soil, and Fresh WaterQuiz5 questions
What does 'recycling' mean?
AThrowing rubbish in the oceanBTurning old materials into new productsCBurning rubbish for fuelDBurying rubbish underground
Environmental · L1 · Recycling & the Three R's Quiz
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Environmental · L1 · Recycling & the Three R's QuizQuiz4 questions
What makes an energy source 'renewable'?
AIt is expensiveBIt never runs outCIt is found undergroundDIt makes smoke
Environmental · L1 · Renewable & Clean Energy Quiz
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Environmental · L1 · Renewable & Clean Energy QuizQuiz4 questions
What is a habitat?
AA type of foodBThe natural home of a plant or animalCA type of weatherDA kind of rock
Environmental · L1 · Habitats & Food Chains Quiz
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Environmental · L1 · Habitats & Food Chains QuizQuiz4 questions
What does it mean when an animal is 'endangered'?
AIt is very commonBIt has so few left that the species could disappearCIt only lives in zoosDIt is a new species
Environmental · L1 · Endangered Animals & Conservation Quiz
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Environmental · L1 · Endangered Animals & Conservation QuizQuiz4 questions
What gas do trees release that people and animals need to breathe?
ACarbon dioxideBOxygenCNitrogenDSmoke
Environmental · L1 · Forests & Deforestation Quiz
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Environmental · L1 · Forests & Deforestation QuizQuiz4 questions
How does plastic litter usually reach the ocean?
AIt falls from the sky as rainBIt washes off land through drains and riversCFish bring it from the deep seaDIt only comes from ships
Environmental · L1 · Ocean Life & Plastic Pollution Quiz
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Environmental · L1 · Ocean Life & Plastic Pollution QuizQuiz4 questions
What is air pollution?
AClean, fresh airBSmoke, gases, or particles that make air dirtyCA type of weatherDWater vapour in clouds
Environmental · L1 · Air Pollution & Clean Air Quiz
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Environmental · L1 · Air Pollution & Clean Air QuizQuiz4 questions
What mainly causes an earthquake?
AHeavy rainBTectonic plates suddenly slippingCStrong windDThe Moon's gravity
Environmental · L1 · Earthquakes Quiz
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Environmental · L1 · Earthquakes QuizQuiz5 questions
What is a 'crop'?
AAn animal raised on a farmBA plant grown on purpose for foodCA type of farm toolDA place where food is sold
Environmental · L1 · Farming & Growing Our Food Quiz
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Environmental · L1 · Farming & Growing Our Food QuizQuiz5 questions
What is the main reason land is turned into a national park?
ATo build more houses on itBTo protect its wildlife, plants, and sceneryCTo use it for farming onlyDTo sell it to visitors
Environmental · L1 · National Parks & Protected Places Quiz
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Environmental · L1 · National Parks & Protected Places QuizQuiz5 questions
What is a landfill?
AA place where recycling is sortedBA large area of land where rubbish is buriedCA bin for food scrapsDA factory that makes new plastic
Environmental · L1 · Litter, Landfills & Composting Quiz
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Environmental · L1 · Litter, Landfills & Composting QuizQuiz5 questions
What is a glacier?
AA fast-flowing river of rainwaterBA huge, slow-moving mass of packed iceCA cloud made of ice crystalsDAn underground lake
Environmental · L1 · Glaciers & Ice Caps Quiz
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Environmental · L1 · Glaciers & Ice Caps QuizQuiz5 questions
How do fold mountains form?
AWind slowly wears rock into peaksBTwo tectonic plates push together, squeezing rock upwardCRain washes soil into pilesDIce carves rock into shape
Environmental · L1 · Mountains: How They Form Quiz
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Environmental · L1 · Mountains: How They Form QuizQuiz5 questions
What actually defines a desert?
AVery hot temperaturesBVery little rain or snowCLots of sandDNo animals living there
Environmental · L1 · Deserts Quiz
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Environmental · L1 · Deserts QuizQuiz5 questions
What is a wetland?
AA dry desert with sand dunesBLand covered by shallow water for part or all of the yearCThe deepest part of the oceanDA frozen glacier
Environmental · L1 · Wetlands & Swamps Quiz
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Environmental · L1 · Wetlands & Swamps QuizQuiz5 questions
What is coral?
AA type of rockBA tiny animal that builds a hard skeletonCA kind of seaweedDA fish
Environmental · L1 · Coral Reefs Quiz
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Environmental · L1 · Coral Reefs QuizQuiz5 questions
Why does the sunlight zone have the most ocean life?
AIt is the coldest zoneBSunlight lets plants and algae grow, feeding the rest of the food webCIt has the least water pressure of all zonesDFish prefer darkness
Environmental · L1 · Ocean Zones Quiz
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Environmental · L1 · Ocean Zones QuizQuiz5 questions
What is animal migration?
AAn animal staying in exactly one place foreverBA regular, often long, seasonal journey between placesCAn animal hibernating in winterDA type of animal habitat
Environmental · L1 · Animal Migration Quiz
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Environmental · L1 · Animal Migration QuizQuiz5 questions
What is a decomposer?
AA living thing that breaks down dead material into nutrientsBA plant that only grows in waterCA machine that shreds leavesDAn animal that only eats other living animals
Environmental · L1 · Worms & Decomposers Quiz
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Environmental · L1 · Worms & Decomposers QuizQuiz5 questions
Why should you turn off a light when you leave a room?
AIt has no real effectBIt stops electricity being wasted on an empty roomCIt makes the room colderDIt is required by law everywhere
Environmental · L1 · Saving Energy at Home Quiz
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Environmental · L1 · Saving Energy at Home QuizQuiz5 questions
Why should you turn off the tap while brushing your teeth?
AA running tap wastes water you are not actually usingBIt makes your teeth cleanerCIt has no real effect on water useDIt saves electricity, not water
Environmental · L1 · Saving Water at Home Quiz
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Environmental · L1 · Saving Water at Home Quiz