414 defs

Lakes formed when permafrost thaws and ground collapses.

Lakes forming in volcano craters or collapsed volcanic cones.

Lakes formed along tectonic faulting, creating deep, steep-walled basins.

Shallow nearshore region where light reaches the bottom, allowing growth of rooted macrophytes.

Open-water region away from shore, extending down to the compensation depth.

Deep, aphotic bottom region below the compensation depth; inhabited by benthic organisms.

Organisms living on or in lake sediments (worms, insect larvae, mollusks).

Drifting organisms with limited ability to swim (phytoplankton + zooplankton).

Upper layer where photosynthesis > respiration. Extends from surface to compensation depth.

Depth at which photosynthetic oxygen production exactly equals respiration.

Measure of the tendency of the environment to accept or donate electrons.

Conversion of organic N to NH4+ by microbes.

Conversion of NH4+ → NO2- → NO3- under aerobic conditions.

Anaerobic reduction of NO3- to N2 gas.

Conversion of N2 gas to NH4+ by cyanobacteria using nitrogenase.

Organic N compounds dissolved in water, including urea and amino acids.

Organic P compounds in the water column.

Algae store excess P when available and use it later during deficiency.

Total photosynthesis unchecked by respiration.

GPP minus phytoplankton respiration.

Total amount of living organisms in a specific area at one time.

Production-to-biomass ratio; indicates turnover rate.

Measures primary production via changes in dissolved oxygen in light and dark bottles.

F = D A C / z (mass transfer rate) describing diffusion-driven exchange.

Lakes dammed by glacial moraines (debris left by glaciers).

Gas transfer velocity describing how quickly gases exchange across the surface film.

Land area draining water into a lake or river.

Portion of streamflow supplied by slow groundwater discharge.

Runoff entering streams during and shortly after rainfall events.

Amount of water produced by a landscape (typically measured as runoff).

Drainage basin that does not drain to the ocean; promotes saline lakes.

Drainage basin where rivers ultimately reach the ocean.

Energy-controlled maximum evaporation possible from landscape surfaces.

Formed when soluble rock (e.g., limestone) dissolves, creating depressions.

U-shaped lake formed when a meandering river bend is cut off.

Small lakes formed on floodplains due to meandering river migration.

Lake formed by erosional scouring beneath waterfalls.

Basins carved by glaciers, forming various lake types.

Formed by valley glaciers gouging bedrock.

Formed at the head of glacial valleys in amphitheater-like hollows.

Glacial valleys flooded by seawater and later uplifted.

A substance that provides food, allowing organisms to grow and survive.

The layer of water that extends from the photic zone to the bottom of the lake.

The difference between gross primary production and cellular respiration; a measure of how much nutrients, especially carbon, are in the system.

Matter that is produced from within the ecosystem.

Lakes that are permanently stratified with a monimolimnion layer (a low-oxygen layer, usually near the bottom).

An independent community of organisms able to move independently by swimming.

Lakes formed from melting blocks of ice trapped within a ground moraine.

Breakage of a material, generally due to compressive stress; ductile materials shift, brittle materials form fault zones.

Thick-walled cells in algae that create low-oxygen zones for nitrogen fixation; lack photosystem II and have adaptations to limit O2.

Organisms that are passively moved around by water currents (microscopic organisms and some invertebrates).

Rate at which light intensity decreases with depth due to absorption and scattering.

Fraction of incoming light reflected off the water surface.

Balance of incoming and outgoing shortwave and longwave radiation at the lake surface.

Heat exchange between lake and atmosphere due to temperature differences.

Heat used for evaporation from the lake surface.

Model describing gas exchange across the thin, stagnant layer at the air-water interface.

Radiolabelling technique used to measure photosynthesis (measures carbon assimilation using radioactive carbonate).

Solubility of a gas is proportional to its partial pressure.

Mixing generated by turbulent eddies, especially strong horizontally.

Distance wind blows over water; controls wave formation.

Rotating water at lake surface; wind-driven spiral cells creating surface streaks of foam and alternating upwelling/downwelling zones.

Standing wave caused by wind piling water on one side of the lake.

Oscillating wave of the thermocline in stratified lakes.

Water moves in smooth, parallel layers with little mixing; occurs at low Reynolds number.

Chaotic, eddy-filled motion with strong mixing; occurs at high Reynolds number.

Predicts laminar vs turbulent flow: Re = U d / ν.

Predicts whether stratification suppresses mixing.

Bulk horizontal transport of water and its contents.

Warm, well-mixed upper layer.

Cold, dense, largely isolated deep layer.

Layer of rapid temperature change separating epilimnion and hypolimnion.

Lake that mixes completely at least once a year.

Never mixes (usually permanently ice-covered in polar regions).

Mixes twice per year (spring and fall).

Mixes once per year.

Mixes many times per year (shallow tropical lakes).

Mixes irregularly or rarely due to warmth in tropical settings.

Feeding on zooplankton.

Feeding on periphyton or filamentous algae.

Feeding on organic detritus.

Predator exerting disproportionately large control on community structure.

Top-down effects where predator abundance affects herbivores and primary producers.

Having multiple generations per year (rotifers, cladocerans).

Only one brood generation per year (some copepods).

Capturing suspended food particles using appendages; influenced by Reynolds constraints.

Seasonal morphological changes in zooplankton (e.g., helmets, spines).

Daily movement up at night and down during the day to balance feeding vs predation risk.

High UV exposure near surface constrains vertical distribution of plankton.

Pathway where DOC → bacteria → protozoa → zooplankton, recycling energy and nutrients.

DOC that absorbs UV/visible light, affecting light penetration and photochemistry.

UV-driven reactions converting CDOM into more labile carbon for bacteria.

Diatoms that remain suspended; they bloom in spring.

Diatoms with a benthic resting phase; resuspended during fall/winter mixing.

Depth where integrated photosynthesis equals integrated respiration.

Level of turbulence needed to keep cells in the euphotic zone.

Describes growth vs nutrient concentration: μ = μmax S / (Ks + S); Ks is the half-saturation constant.

Nutrient concentration at which growth is half maximal.

Enzyme that breaks down organic P to inorganic phosphate; produced under P limitation to liberate PO4³⁻ from organic compounds.

Release of P from anoxic sediments back into the water column.