Ecology, Biogeochemical Cycles, and Ecosystem Dynamics Flashcards

Comprehensive vocabulary flashcards generated from lecture transcript notes covering ecological processes, biogeochemical cycles, primary productivity, freshwater and marine biomes, and species interactions.

Evaporation

The process in the water cycle where liquid water changes into water vapor, caused by energy from the Sun.

Transpiration

The process in which plants release water vapor into the atmosphere.

Precipitation

Water falling from the atmosphere to Earth's surface as rain, snow, sleet, or hail.

Infiltration

The process by which water enters and moves through the soil.

Runoff

Water that flows across the land surface into rivers, lakes, and oceans.

Groundwater

Water stored underground within soil and rock formations.

Watershed

An area of land where all rain and snowmelt drain into a common body of water, with boundaries determined by elevation.

Primary Productivity

The rate at which producers convert solar energy into glucose via photosynthesis, measured in units like $\text{Kcal/m}^2/\text{year}$.

Gross Primary Production ($GPP$)

The total energy stored from photosynthesis by producers before any energy is used for respiration.

Respiration ($R$)

The cellular energy used by producers to live and grow.

Net Primary Production ($NPP$)

The energy stored as biomass that can be passed on to consumers, calculated using the formula $NPP = GPP - R$.

Aerobic Respiration

Cellular respiration that uses oxygen to break down glucose for energy, producing carbon dioxide and water ($Glucose + O_2 \rightarrow CO_2 + H_2O + \text{energy}$).

Anaerobic Respiration

Cellular respiration that occurs without oxygen.

Combustion

The process of burning biomass or fossil fuels, which releases carbon into the atmosphere as $CO_2$ and energy.

Methane ($CH_4$)

A common greenhouse gas in the atmosphere containing carbon that is less abundant than $CO_2$ but contributes to global warming.

Carbon Sink

An ecosystem component, such as oceans, forests, soil, and plant life, that stores more carbon than it releases.

Carbon Source

An ecosystem reservoir, such as the atmosphere, that releases carbon.

Nitrogen Fixation

The first step of the nitrogen cycle where nitrogen-fixing bacteria in soil or plant roots convert atmospheric nitrogen ($N_2$) into ammonium ($NH_3$ / $NH_4$) that organisms can use.

Nitrification

The step in the nitrogen cycle where soil bacteria convert ammonium into nitrites ($NO_2$) and then nitrates ($NO_3$).

Assimilation (Nitrogen Cycle)

The process by which plants absorb nitrate ($NO_3$) through their roots to produce proteins and nucleic acids, which animals then obtain by eating plants.

Ammonification

The process where decomposers break down dead organisms and waste, restoring usable nitrogen ($NH_3$ / $NH_4$) into the soil.

Denitrification

The final step of the nitrogen cycle where bacteria convert nitrate ($NO_3$) back into atmospheric nitrogen gas ($N_2$).

Eutrophication

A process where a body of water becomes overly enriched with nutrients, causing excessive algal blooms that severely damage aquatic ecosystems.

Phosphorus Cycle

A slow biogeochemical cycle involving weathering of rocks, soil uptake, consumption, decomposition, and sedimentation, characterized by having little to no atmospheric phase.

Point Source Pollution

Pollution originating from a single, identifiable location, such as a pipe releasing effluent into a body of water.

Nonpoint Source Pollution

Pollution originating from scattered, diffuse sources, such as agricultural fertilizer runoff.

Lotic Systems

Flowing freshwater ecosystems such as rivers and streams, where turbulence increases dissolved oxygen levels.

Lentic Systems

Standing freshwater ecosystems such as ponds and lakes.

Littoral Zone

The shallow freshwater lake zone near the shore characterized by high light availability and high Net Primary Productivity ($NPP$).

Limnetic Zone

The open surface water zone of a lake where light penetrates.

Benthic Zone

The bottom zone of a body of water receiving little to low light.

Oligotrophic Lake

A deep, clear lake characterized by low nutrient levels and low primary productivity.

Eutrophic Lake

A shallow, often less clear lake characterized by high nutrient levels and high primary productivity.

Estuary

A coastal aquatic biome where freshwater meets saltwater, creating brackish water with high nutrients, productivity, and biodiversity.

Photic Zone

The upper layer of ocean water where sufficient sunlight penetrates to allow photosynthesis.

Aphotic Zone

Deeper ocean water where no sunlight reaches, preventing photosynthesis.

Coastal Upwelling

An ocean process where wind pushes surface water away, causing cold, nutrient-rich deep water to rise to the photic zone, increasing $NPP$ and biodiversity.

Biotic Factors

Living components of an ecosystem, such as plants, animals, and bacteria.

Abiotic Factors

Nonliving components of an ecosystem, such as rocks, temperature, precipitation, sunlight, humidity, and wind.

Limiting Factor

An environmental resource whose demand exceeds supply, causing competition and restricting population growth.

Intraspecific Competition

Competition for resources occurring between individuals of the same species.

Interspecific Competition

Competition for resources occurring between individuals of different species.

Competitive Exclusion Principle

The ecological concept stating that two species competing for the exact same limited resources cannot coexist in the same niche indefinitely.

Resource Partitioning

An evolutionary adaptation where different species utilize distinct resources to reduce direct competition.

Keystone Species

A species, often a predator, that exerts a disproportionately large impact on the structure and balance of its ecosystem.

Indicator Species

A species sensitive to environmental shifts that provides early warnings of changes in ecosystem health.

Ecosystem Engineers

Species that physically modify their environment, creating conditions that other organisms rely on for survival.

Trophic Cascade

A chain reaction in an ecosystem where changes in the population of one species cause dramatic, widespread biotic and abiotic changes throughout the food web.

Chemosynthesis

A process used by certain aquatic organisms in dark environments where light is absent to produce organic matter without sunlight.

Light Attenuation in Water

The absorption of solar light wavelengths in aquatic biomes, where red light is absorbed in the top $1\text{ meter}$ and blue light penetrates deepest to approximately $100\text{ meters}$.