53 articles
Acid neutralizing capacity
Acid neutralizing capacity (ANC) is a measure of the ability of water or soil to neutralize added acids, serving as the standard indicator of surface water sensitivity to acidification.
Alternative stable states
Alternative stable states are distinct self-maintaining ecosystem configurations possible under identical environmental conditions, an idea from the 1960s with shallow lakes as the classic example.
Anammox
Anammox, short for anaerobic ammonium oxidation, is a microbial process in which bacteria convert ammonium and nitrite into nitrogen gas, discovered in 1995 and now used to treat wastewater.
Anatoxin-a
Anatoxin-a (ATX-a) is a potent neurotoxic bicyclic amine alkaloid produced by freshwater cyanobacteria, which acts on the nicotinic acetylcholine receptor and can cause neurological disorders and death.
Benthic boundary layer
The benthic boundary layer is the region of water directly above a lake, river, or ocean sediment, where flow and solute transport are shaped by the sediment surface.
Bottom-up control (ecology)
Bottom-up control is the regulation of a food web from its base, where resources like nutrients determine higher trophic levels, contrasting with top-down control by predators.
Brownification
Brownification, also called browning, is the increase in the yellow-brown color of inland waters, driven mainly by rising dissolved organic matter of terrestrial origin across the Northern Hemisphere.
Bubble plume
A bubble plume is a vertical, buoyancy-driven flow formed when gas is released through a diffuser at the bottom of a stratified lake, mixing water layers as it rises.
Ceriodaphnia
Ceriodaphnia is a genus of small freshwater water fleas in the family Daphniidae, whose species Ceriodaphnia dubia is a standard organism in regulatory aquatic toxicity testing.
Chlorophyll maximum
A chlorophyll maximum, also called the deep chlorophyll maximum (DCM) or subsurface chlorophyll maximum, is a layer in stratified lakes and oceans where chlorophyll-a peaks below the surface, often accounting for much of primary production.
Coastal boundary layer
The coastal boundary layer (CBL) is the inshore region of a large lake or coastal ocean where the shore shapes currents, mixing, and transport, also called the inner shelf.
Convective mixing
Convective mixing is the vertical mixing of a fluid driven by buoyancy, and in lakes it is often the dominant driver of mixing and stratification.
Critical load
A critical load is the estimated deposition of a pollutant, most often acidifying sulfur and nitrogen compounds, below which significant harmful effects on a sensitive ecosystem do not occur.
Cultural eutrophication
Cultural eutrophication is the human-caused acceleration of eutrophication, the over-enrichment of waters with nitrogen and phosphorus from sewage, fertilizers, and detergents, driving algal blooms and oxygen depletion.
Cylindrospermopsin
Cylindrospermopsin is an alkaloid toxin produced by freshwater cyanobacteria that inhibits protein synthesis, damaging the liver and kidneys. First isolated in 1992, it was the likely cause of a 1979 mass poisoning on Palm Island, Australia.
Daphnia pulex
Daphnia pulex, commonly called the water flea, is a widespread freshwater crustacean that grazes algae in lakes and ponds and was the first crustacean to have its genome sequenced.
Dead Sea (ים המלח)
The Dead Sea (ים המלח) is a hypersaline terminal lake in the Jordan Rift Valley between Jordan and Israel, about ten times saltier than the ocean.
Destratification
Destratification is the artificial mixing of a thermally stratified lake or reservoir, usually by injecting compressed air, to make temperature and dissolved oxygen roughly uniform throughout.
Dissolved organic carbon
Dissolved organic carbon (DOC) is the organic carbon in water that passes a 0.45-micrometer filter, making up about 90% of total organic carbon in most waters.
Dissolved oxygen
Dissolved oxygen (DO) is the amount of oxygen gas dissolved in water and available to aquatic organisms, usually reported in mg/L, and a core measure of water quality.
Double-diffusive convection
Double-diffusive convection, first called thermohaline convection, arises when a fluid's density depends on two components, like heat and salt, that diffuse at very different rates.
Epilimnion
The epilimnion is the warm, well-mixed upper layer of a stratified lake, holding the warmest water and mixed by wind, typically 10 to 40 feet thick.
Experimental Lakes Area
The Experimental Lakes Area is a research region of 58 small lakes in northwestern Ontario, Canada, set aside in 1968, where scientists manipulate entire lake ecosystems to study pollution.
Fetch (oceanography)
Fetch, in oceanography, is the area of open water over which wind blows in a roughly constant direction and generates waves, determining wave size alongside wind speed and duration.
Floating island
A floating island is a buoyant mass of vegetation, peat, or other material resting on a lake's surface, occurring naturally in wetlands and built deliberately for water treatment.
Haematococcus pluvialis
Haematococcus pluvialis is a freshwater unicellular green microalga that accumulates astaxanthin in thick-walled resting cells under stress, making it the primary natural source for supplements.
Hydraulic control
Hydraulic control is the condition in stratified or open-channel flow where long waves cannot travel upstream, typically at a sill crest, governing exchange through straits and fjords.
Hypolimnion
The hypolimnion is the cold, dense bottom layer of a stratified lake, lying beneath the thermocline and cut off from atmospheric oxygen during summer stratification.
Ice cover dynamics
Ice cover dynamics is the study of the seasonal cycle of freezing, thickening, and thawing on lakes, summarized by ice phenology and used to track climate change.
Internal phosphorus loading
Internal phosphorus loading is the release of phosphorus from a lake's own sediments into the water, distinct from external loading, and often the main summer phosphorus load in eutrophic lakes.