Untitled Flashcard Set

Primary productivity & energy flow
Primary productivity – Rate at which producers convert solar energy into organic compounds over time (photosynthesis rate per area).
Gross primary productivity (GPP) – Total solar energy captured by producers and fixed as chemical energy (glucose).
Respiration loss (RL) – Energy producers use for cellular respiration and maintenance that is not stored as biomass.
Net primary productivity (NPP) – Energy/biomass available to consumers; NPP = GPP − RL.
Ecological efficiency (producer level) – Small fraction of incoming sunlight captured; ~1% becomes GPP and ~0.4% becomes NPP.
10% rule (energy) – About 10% of energy transfers to the next trophic level; ~90% is used or lost as heat.
10% rule (biomass) – Only ~10% of biomass at one trophic level can be supported at the next level.
Trophic level – Position in a food chain (producer, primary consumer, secondary consumer, tertiary consumer).
Primary consumer – Herbivore that eats producers.
Secondary consumer – Carnivore/omnivore that eats herbivores.
Tertiary consumer – Predator feeding on secondary consumers (often apex).
First law of thermodynamics – Energy is conserved; it changes form but is neither created nor destroyed.
Second law of thermodynamics – Every energy transfer loses usable energy as heat; less usable energy at higher trophic levels.
Factors increasing NPP – High water availability, warm temperatures, and nutrient availability.
Trophic cascade – Top-down effect where predators indirectly benefit lower trophic levels by controlling herbivores.

Ecosystem & interactions
Ecosystem – All living and nonliving components interacting in an area.
Community – All living organisms in an area.
Population – Individuals of the same species in an area.
Biome – Regional community of plants/animals defined by long-term temperature and precipitation.
Weather – Short-term atmospheric conditions.
Climate – Long-term average weather in a location.
Mutualism – Symbiosis where both species benefit (e.g., coral and algae).
Commensalism – One species benefits, the other is unaffected.
Parasitism – One species benefits at the other’s expense without immediate killing (parasites).
Parasitoid – Lays eggs in/on host; larvae consume and usually kill host.
Predation – One organism consumes another for energy.
Competition – Organisms vie for limited resources, reducing population sizes.
Resource partitioning – Species reduce competition by using the same resource in different ways/times/places.
Temporal partitioning – Using resources at different times (e.g., day vs. night).
Spatial partitioning – Using different areas or depths of a habitat.
Morphological partitioning – Using resources differently due to body differences.
Shifting biomes – Biomes shift geographically as climate changes (e.g., boreal forest moves poleward).

Terrestrial biomes (core traits)
Tropical rainforest – Warm, very wet, dense vegetation; nutrient-poor soils due to rapid uptake/competition.
Temperate rainforest – Cool to mild with high rainfall, rich foliage; can have rich soils and conifer/broadleaf mix.
Temperate seasonal forest (deciduous) – Seasonal temperature, moderate precipitation; nutrient-rich loamy soils from leaf litter.
Shrubland (chaparral) – Open, woody shrubs/short trees; low nutrients due to heat and dryness.
Temperate grassland (prairie/steppe) – Semiarid, few trees, very fertile deep soils from grass root turnover.
Savanna – Warm with distinct wet/dry seasons; grasses with scattered trees; low soil nutrients, high competition.
Desert – Driest biome, sparse drought-adapted vegetation; nutrient-poor soils from low organic matter/weathering.
Tundra – Coldest biome, low precipitation, permafrost, short growing season, limited nutrients.
Taiga (boreal forest) – Cold, conifer-dominated, nutrient-poor soils from low decomposition rates.
Latitude–biome pattern – Tundra/boreal at high latitudes, temperate at mid-latitudes, tropical near the equator.

Aquatic fundamentals
Depth (light penetration) – Controls photosynthesis below surface; defines photic vs. aphotic zones.
Temperature (aquatic) – Warmer water holds less dissolved oxygen, supporting fewer organisms.
Salinity – Salt concentration determines species tolerance and water use (fresh vs. estuary vs. ocean).
Flow – Water movement shapes habitat, oxygenation, and species survival.
Dissolved oxygen (DO) – Oxygen in water; generally higher in fast-flowing rivers due to mixing.

Freshwater systems
River – Flowing freshwater with high DO and sediment transport; forms fertile deltas/floodplains.
Lake – Standing freshwater; key drinking source with distinct light/plant zones.
Littoral zone – Shallow, near-shore area with rooted emergent plants.
Limnetic zone – Open-water, well-lit zone where phytoplankton photosynthesize; few rooted plants.
Profundal zone – Deep, dark lake zone with no photosynthesis.
Benthic zone – Bottom sediments; nutrient-rich, supports invertebrates.
Wetland – Ground is submerged/saturated part of the year; supports emergent plants and provides flood control, groundwater recharge, and pollutant filtration.
Swamp – Forested wetland (woody plants).
Marsh – Non-woody wetland dominated by reeds/cattails.
Bog – Wetland with highly acidic soils, often sphagnum-rich.

Estuaries & marine
Estuary – Where rivers meet the ocean; brackish water, high productivity from nutrient-rich sediments.
Salt marsh – Temperate estuary habitat, crucial nursery for fish/shellfish.
Mangrove swamp – Tropical estuary habitat with stilt-rooted trees that stabilize shorelines and offer nursery habitat.
Coral reef – Warm, shallow, most diverse marine biome; coral–algae mutualism and calcium carbonate reef building.
Intertidal zone – Shoreline between high/low tide; organisms adapt to wave action and desiccation.
Open ocean – Low productivity per area; photic zone allows photosynthesis, aphotic is too deep for light; ocean biota act as a major CO₂ sink.

Carbon cycle (C)
Carbon sink – Reservoir taking in more carbon than it releases (ocean, plants, soils).
Carbon source – Reservoir releasing more carbon than it absorbs (FF combustion, deforestation, animal agriculture CH₄).
Photosynthesis – CO₂ + H₂O → C₆H₁₂O₆ + O₂; pulls CO₂ from air/water into biomass.
Cellular respiration – C₆H₁₂O₆ + O₂ → CO₂ + H₂O + energy; returns CO₂ to atmosphere.
Direct exchange (air–sea) – Rapid two-way CO₂ exchange between atmosphere and ocean surface waters.
Ocean acidification – Rising oceanic CO₂ lowers pH.
Marine calcification – Coral and shell-formers use dissolved C to build CaCO₃ skeletons/shells.
Sedimentation – Carbonate and organic particles settle to the seafloor, forming sediments.
Burial – Long-term geological storage of carbon in sedimentary rocks and fossil fuels.
Extraction and combustion – Mining/drilling fossil fuels and burning them; adds CO₂ to atmosphere.

Nitrogen cycle (N)
Main reservoir – Atmosphere (N₂ gas), biologically unavailable without conversion.
Nitrogen fixation (biotic) – Soil or symbiotic bacteria convert N₂ to NH₃/NH₄⁺; legumes host rhizobacteria in root nodules.
Nitrogen fixation (abiotic/synthetic) – Human processes (e.g., fertilizer production; FF combustion producing reactive N) yield NH₃/NOₓ for ecosystems.
Nitrification – Soil bacteria convert NH₄⁺ → NO₂⁻ → NO₃⁻.
Assimilation (N) – Plants take up NH₃/NH₄⁺/NO₃⁻; animals obtain N by eating.
Ammonification – Decomposers convert organic N in waste/dead biomass to NH₃/NH₄⁺.
Denitrification – Anaerobic bacteria convert NO₃⁻ to gaseous forms (N₂O, N₂), returning N to atmosphere.
Leaching (nitrate) – NO₃⁻ is water-soluble and can be carried from soils into groundwater/surface waters.
Ammonia volatilization – Excess NH₃ from fertilizers enters the atmosphere.
Nitrous oxide (N₂O) – Greenhouse gas produced during denitrification; warms climate.

Phosphorus cycle (P)
Main reservoirs – Rocks and sediments containing phosphate minerals; no significant atmospheric gas phase.
Weathering – Wind/rain break down rocks, releasing phosphate (PO₄³⁻) to soils and waters.
Limiting nutrient (P) – Slow cycling and low solubility make P limiting for plant growth in many ecosystems.
Assimilation (P) – Plants absorb phosphate; animals obtain P by feeding.
Excretion/decomposition (P) – Returns phosphate to soils; low solubility leads to sedimentation.
Sedimentation (P) – Insoluble phosphates settle as sediments, forming long-term reservoirs.
Geological uplift – Tectonics raise sedimentary rocks, exposing P to weathering again.
Anthropogenic P sources – Mining phosphates for fertilizers/detergents adds P to waters via runoff and wastewater.
Eutrophication – Excess N and P fuel algal blooms that block light; decomposition consumes dissolved oxygen, causing fish kills and a positive feedback of further O₂ loss.

Hydrologic (water) cycle
Largest water reservoir – The ocean.
Freshwater reservoirs – Ice caps/glaciers and groundwater aquifers (key usable freshwater).
Evaporation – Liquid water becomes vapor due to solar energy.
Transpiration – Plants pull water from roots to leaves; water exits stomata as vapor.
Evapotranspiration – Combined water vapor flux from evaporation and transpiration.
Runoff – Precipitation flowing over land into surface waters.
Infiltration – Water percolating into soil to recharge groundwater; depends on soil permeability.
Aquifer – Underground water-bearing rock/sediment storing groundwater.

Policy & human impacts
Clean Water Act (CWA) – U.S. law (1972) to restore/maintain water integrity by regulating pollutant discharges, setting water-quality standards, funding treatment facilities, covering waters with continuous surface connection to navigable waters, and enforcing via EPA/states