Global Change Ecology: Air, Fire, Nutrient Cycles, and Plastic Pollution

Comprehensive vocabulary flashcards covering the ecological impacts and mechanisms of plastic pollution, nitrogen and phosphorus biogeochemical cycling, wildfire adaptations and drought metrics, stratospheric ozone depletion, and global climate change solutions.

Microplastics

Synthetic plastic particles measuring less than $5\,\text{mm}$ in length, resulting from the fragmentation of larger macroplastics, shedding from synthetic textiles, or industrial manufacturing.

Plastic Rain

The atmospheric transport and wet or dry deposition of microplastics onto remote, undeveloped regions, such as pristine mountain catchments in the French Pyrenees at an average rate of $365\,\text{particles}\,\text{m}^{-2}\,\text{d}^{-1}$.

Leo Baekeland

The chemist who created Bakelite in New York in 1907 by reacting phenol (derived from coal tar) with formaldehyde, producing the world's first fully synthetic plastic.

Plastic Resin Identification Codes

A standardized numbering system (1 through 7) established to classify plastic polymer types (PETE, HDPE, PVC, LDPE, PP, PS, and OTHER) to facilitate sorting and recycling.

Harmful Algal Blooms (HABs)

Rapid proliferations of algae or cyanobacteria in freshwater or marine environments triggered by excess nutrient runoff (nitrogen and phosphorus), often producing potent biotoxins and deoxygenating waters.

Microcystins

A group of potent hepatotoxins produced by cyanobacterial genera such as Microcystis, Anabaena, and Planktothrix that cause liver damage, illness, and mortality in wildlife, livestock, and humans.

Anatoxin-a

A potent cyanobacterial neurotoxin known as the "Very Fast Death Factor" (VFDF) that induces rapid muscular paralysis and respiratory arrest within minutes of ingestion.

Riparian Buffer

A vegetated strip of trees, shrubs, and perennial plants maintained along streams and rivers to intercept and filter sediment, nitrogen, and phosphorus from agricultural surface runoff.

Low-Impact Development (LID)

A land planning and stormwater engineering framework (also known as WSUD or SUDS) that uses green infrastructure such as bioswales, rain gardens, and constructed wetlands to slow and filter urban runoff.

Dead Zone (Hypoxia)

An aquatic or marine zone exhibiting severely depleted dissolved oxygen levels ($\text{hypoxia}$), driven by microbial decomposition of extensive algal blooms fueled by upstream fertilizer and wastewater inputs.

Coupling of N and P Cycles

The ecological interaction wherein the retention and denitrification of nitrogen in aquatic ecosystems depends on sufficient phosphorus availability to support algal biomass growth and organic burial.

AOT40

An accumulated exposure index for plant ozone injury, calculated as the sum of daylight hourly tropospheric $\text{O}_3$ concentrations exceeding $40\,\text{ppb}$ during the primary growing season (April 1 to September 30 in the Northern Hemisphere).

Liebig's Law of the Minimum

The ecological principle stating that biological growth and primary productivity are controlled not by total resources available, but by the scarcest essential resource (the limiting factor).

Reactive Nitrogen ($\text{N}_r$)

All biologically active, chemically reactive, and radiatively active nitrogen compounds—including $\text{NH}_4^+$, $\text{NO}_3^-$, $\text{NO}_x$, and $\text{N}_2\text{O}$—in contrast to unreactive atmospheric dinitrogen ($\text{N}_2$).

Biological Nitrogen Fixation (BNF)

The enzymatic conversion of atmospheric dinitrogen ($\text{N}_2$) into ammonium ($\text{NH}_4^+$) by specialized prokaryotes, such as symbiotic rhizobia in legume root nodules and free-living or colonial cyanobacteria.

Haber-Bosch Process

An industrial chemical synthesis that combines atmospheric nitrogen gas with hydrogen gas under high heat and pressure ($\text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3$) to produce ammonia for synthetic agricultural fertilizers.

Nitrification

A biological two-step aerobic process carried out by soil microorganisms that oxidizes ammonium ($\text{NH}_4^+$) first to nitrite ($\text{NO}_2^-$) and subsequently to highly mobile nitrate ($\text{NO}_3^-$).

Denitrification

The anaerobic microbial respiratory pathway converting aqueous nitrate ($\text{NO}_3^-$) sequentially through nitrite, nitric oxide ($\text{NO}$), and nitrous oxide ($\text{N}_2\text{O}$) back into inert atmospheric dinitrogen gas ($\text{N}_2$).

Phosphine ($\text{PH}_3$)

A volatile, flammable phosphorus gas released from decaying organic matter in anaerobic wetlands, the spontaneous combustion of which creates natural atmospheric luminescence known as will-o'-the-wisp.

Photodissociation

The cleavage of a chemical bond by solar electromagnetic radiation, such as ultraviolet light splitting molecular oxygen ($\text{O}_2 \rightarrow 2\text{O}$) or releasing reactive halogen free radicals from halocarbons.

Polar Stratospheric Clouds (PSCs)

High-altitude clouds of ice crystals and nitric acid trihydrate that form below $-78\,^\circ\text{C}$ in polar winter vortices, providing catalytic solid surfaces for halogen activation that drives stratospheric ozone depletion.

Dobson Unit (DU)

A standard unit of measurement for total column atmospheric trace gas abundance, representing the physical thickness of the gas layer if compressed to standard temperature and pressure ($1\,\text{DU} = 0.01\,\text{mm}$ pure gas layer).

Montreal Protocol

The 1987 international treaty entered into force in 1989 that instituted binding global phase-out schedules for chlorofluorocarbons (CFCs), halons, and other halogenated ozone-depleting substances.

Antarctic Ozone Hole

A seasonal, severe thinning of stratospheric ozone occurring over Antarctica each austral spring due to the combined effects of halogen activation on polar stratospheric clouds and strong polar vortex isolation.

Plant Fire Adaptations

Evolutionary traits enabling plants to survive or regenerate after wildfires, including underground woody lignotubers, epicormic bud sprouting beneath thick bark, post-fire heat-triggered flowering, and serotinous cones.

Lignotuber

A swollen, woody subterranean swelling at the base of the stem or root crown containing latent buds and stored starch reserves that facilitates vigorous vegetative basal resprouting following fire destruction of top growth.

Epicormic Resprouting

Vegetative regeneration occurring from dormant vegetative meristems situated beneath insulating bark along the trunk and major branches of woody plants after fire defoliates the canopy.

Serotiny

An ecological reproductive adaptation where mature seed cones or woody capsules remain closed on the plant, opening to disperse viable seeds only upon exposure to elevated heat from wildfires.

Standardized Precipitation Evapotranspiration Index (SPEI)

A multiscalar drought metric that incorporates both precipitation and temperature-driven potential evapotranspiration to model regional landscape climatic water balance anomalies and drought severity.

Event Attribution Science

A climate science methodology that quantifies whether and to what degree anthropogenic climate change altered the probability, magnitude, or frequency of a specific extreme meteorological disturbance.

Nitrogen Oxides ($\text{NO}_x$)

The collective term for nitric oxide ($\text{NO}$) and nitrogen dioxide ($\text{NO}_2$), produced predominantly during high-temperature combustion in motor vehicles and fossil fuel power plants, acting as precursors to tropospheric ozone and nitric acid rain.

Tropospheric Ozone Photolysis

The chemical formation of ground-level ozone through the absorption of solar ultraviolet radiation by nitrogen dioxide ($\text{NO}_2 \xrightarrow{h\nu} \text{NO} + \text{O}$), followed by reaction of atomic oxygen with oxygen gas ($\text{O} + \text{O}_2 \rightarrow \text{O}_3$).

Ozone Depletion Potential (ODP)

A relative index quantifying the total amount of stratospheric ozone destroyed by a chemical substance over its lifetime, defined relative to the benchmark value of $1.0$ for trichlorofluoromethane ($\text{CFC-11}$).

Fugitive Emissions

Unintended or non-routine leaks of greenhouse gases, primarily methane ($\text{CH}_4$), escaping from pressurized natural gas infrastructure, well drilling heads, transport pipelines, and industrial valves.

Global Warming Potential (GWP)

A relative measure of the quantity of heat a greenhouse gas traps in the atmosphere over a defined time horizon (typically 100 years) compared to the same mass of carbon dioxide ($\text{CO}_2$).

Natural Climate Solutions (NCS)

Conservation, ecological restoration, and land management interventions—such as reforestation, avoided deforestation, and wetland conservation—that sequester atmospheric carbon or prevent greenhouse gas releases.

Project Drawdown

A global research framework evaluating and ranking climate solutions to determine the future point in time when greenhouse gas concentrations in the atmosphere stop rising and begin a steady downward decline.

Direct Air Carbon Capture and Storage (DACCS)

An engineered negative-emissions technology that extracts carbon dioxide directly from ambient air using chemical absorbents and permanently stores it underground, such as mineralizing into calcite within basalt formations.

$$\text{PM}_{2.5}$$

Fine inhalable atmospheric particulate matter with aerodynamic diameters measuring equal to or less than $2.5\,\mu\text{m}$, capable of penetrating deeply into human alveoli and the cardiovascular bloodstream.

Flue-Gas Scrubbers

Air pollution control systems installed in the exhaust smokestacks of industrial facilities and coal-fired electric utilities to neutralize and remove sulfur dioxide ($\text{SO}_2$) prior to atmospheric release.