Freshwater ecosystem

Freshwater angelfish

Freshwater ecosystems are a subset of Earth's aquatic ecosystems. They include lakes and ponds, rivers, streams, springs, and wetlands. They can be contrasted with marine ecosystems, which have a larger salt content. Freshwater habitats can be classified by different factors, including temperature, light penetration, and vegetation.

Freshwater ecosystems can be divided into lentic ecosystems (still water) and lotic ecosystems (flowing water).

Limnology (and its branch freshwater biology) is a study about freshwater ecosystems. It is a part of hydrobiology.

Original efforts to understand and monitor freshwater ecosystems were spurred on by threats to human health (ex. Cholera outbreaks due to sewage contamination). Early monitoring focussed on chemical indicators, then bacteria, and finally algae, fungi and protozoa. A new type of monitoring involves differing groups of organisms (macroinvertebrates, macrophytes and fish) and the stream conditions associated with them.

Current biomonitoring techniques focus mainly on community structure or biochemical oxygen demand. Responses are measured by behavioural changes, altered rates of growth, reproduction or mortality. Macroinvertebrates are most often used in these models because of well known taxonomy, ease of collection, sensitivity to a range of stressors, and their overall value to the ecosystem. Most of these measurements are difficult to extrapolate on a large scale, however.

The use of reference sites is common when assessing what a healthy freshwater ecosystem should “look like”. Reference sites are easier to reconstruct in standing water than moving water. Preserved indicators such as diatom valves, macrophyte pollen, insect chitin and fish scales can be used to establish a reference ecosystem representative of a time before large scale human disturbance.

Common chemical stresses on freshwater ecosystem health include acidification, eutrophication and copper and pesticide contamination.

Extinction of freshwater fauna

Over 123 freshwater fauna species have gone extinct in North America since 1900. Of North American freshwater species, an estimated 48.5% of mussels, 22.8% of gastropods, 32.7% of crayfishes, 25.9% of amphibians, and 21.3% of fishes are either endangered or threatened. Extinction rates of many species may increase severely into the next century because of invasive species, loss of keystone species, and species which are already functionally extinct. Projected extinction rates for freshwater animals are around five times greater than for land animals, and are comparable to the rates for rainforest communities. Recent extinction trends can be attributed largely to sedimentation, stream fragmentation, chemical and organic pollutants, dams, and invasive species.

References

Bibliography

Leathwick J.R.; Collier K.; Chadderton L. (2007) "Identifying freshwater ecosystems with nationally important natural heritage values: development of a biogeographic framework". Science for Conservation 274. p. 30. Department of Conservation (New Zealand).
Friberg, N, Bonada, N., Bradley, D.C., Dunbar, M.J., Edwards, F.K., Grey, J., Hayes, R.B., Hildrew, A.G., Lamouroux, N., Trimmer, M., Woodward G., (2011). Biomonitoring of Human Impacts in Freshwater Ecosystems: The Good, the Bad and the Ugly. Advances in Ecological Research, 1-68.
Ricciardi, A., & Rasmussen, J. B. (1999). Extinction Rates of North American Freshwater Fauna. Conservation Biology, 13 (5), 1220-1222.
XU, F.L., Tao, S., Dawson, R. W., Pen-gang, L., & Jun, C. (2001). Lake Ecosystem Health Assessment: Indicators and Methods. Water Research, 3157-3167.

External links

Wikimedia Commons has media related to Freshwater ecosystems.

Freshwater Biology Journal homepage

Aquatic ecosystems – general and freshwater components

General	Acoustic ecology Adaptation Agent-based models Algal bloom Anoxic waters Aquatic animals (Insects Mammals) Aquatic plants Aquatic science Benthos Biodiversity research Bioluminescence Biomass Biomonitoring Cascade effect Colored dissolved organic matter Camouflage & Mimicry Dead zone Ecohydrology Ecosystems Eutrophication Fisheries science Food chain Food web GIS and aquatic science Hydrobiology Hypoxia Isotope analysis Microbial ecology Microbial food web Microbial loop Nekton Neuston Particle Pelagic zone Photic zone Phytoplankton Plankton Pleuston Predation Productivity Ramsar Convention Respiration Schooling Sediment trap Siltation Spawning Substrate Thermal pollution Toxicology Trophic level Water column Zooplankton More...

Freshwater	Biology Biomes Ecosystems freshwater lake river Fish Hyporheic zone Limnology Lake stratification Macrophyte Pond fish pond Rheotaxis Stream bed Stream pool Trophic state index Upland and lowland Water garden Wetland brackish marsh freshwater marsh swamp bog fen Environmental quality More...

Ecoregions	Freshwater (List) Marine (List) The Everglades Maharashtra The North Pacific Subtropical Gyre The San Francisco Estuary

Aquatic ecosystems – marine components

Marine	Marine biology Marine chemistry Deep scattering layer Diel vertical migration Ecosystems large marine marine) f-ratio Iron fertilization Marine snow Ocean nourishment Oceanic physical-biological process Ocean turbidity Photophore Thorson's rule Upwelling Whale fall More...

Marine life forms	Bacteriophages Census Fish coastal coral reef deep sea demersal pelagic Deep sea communities Deep sea creature Deep-water coral Invertebrates Larvae Mammals Paradox of the plankton Reptiles Seabirds Seashore wildlife Vertebrates Wild fisheries

Marine habitats	Bay mud Black smokers Coastal biogeomorphology Cold seeps Coral reefs Davidson Seamount Estuaries Intertidal ecology Intertidal wetlands Kelp forests Hydrothermal vents Lagoons Mangroves Marine biomes Marine habitats Mudflats Rocky shores Salt marshes Salt pannes and pools Seagrass meadows Sponge reefs Tide pools

Issues	Ecological values of mangrove Fisheries and climate change HERMIONE Marine conservation Marine conservation activism Marine pollution Marine Protected Area

Groups of organisms in aquatic ecosystems

Benthos Macrobenthos Meiobenthos Herpon Nekton Neuston Pechton / Pecton / Pekton Plankton Pleuston Plocon Seston Tripton

Modelling ecosystems – trophic components

General	Abiotic component Abiotic stress Behaviour Biogeochemical cycle Biomass Biotic component Biotic stress Carrying capacity Competition Ecosystem Ecosystem ecology Ecosystem model Keystone species List of feeding behaviours Metabolic theory of ecology Productivity Resource

Producers	Autotrophs Chemosynthesis Chemotrophs Foundation species Mixotrophs Myco-heterotrophy Mycotroph Organotrophs Photoheterotrophs Photosynthesis Photosynthetic efficiency Phototrophs Primary nutritional groups Primary production

Consumers	Apex predator Bacterivore Carnivores Chemoorganotroph Foraging Generalist and specialist species Intraguild predation Herbivores Heterotroph Heterotrophic nutrition Insectivore Mesopredator release hypothesis Omnivores Optimal foraging theory Predation Prey switching

Decomposers	Chemoorganoheterotrophy Decomposition Detritivores Detritus

Microorganisms	Archaea Bacteriophage Environmental microbiology Lithoautotroph Lithotrophy Microbial cooperation Microbial ecology Microbial food web Microbial intelligence Microbial loop Microbial mat Microbial metabolism Phage ecology

Food webs	Biomagnification Ecological efficiency Ecological pyramid Energy flow Food chain Trophic level

Example webs	Cold seeps Hydrothermal vents Intertidal Kelp forests Lakes North Pacific Subtropical Gyre Rivers San Francisco Estuary Soil Tide pool

Processes	Ascendency Bioaccumulation Cascade effect Climax community Competitive exclusion principle Consumer-resource systems Copiotrophs Dominance Ecological network Ecological succession Energy quality Energy Systems Language f-ratio Feed conversion ratio Feeding frenzy Mesotrophic soil Nutrient cycle Oligotroph Paradox of the plankton Trophic cascade Trophic mutualism Trophic state index

Defense/counter	Animal coloration Antipredator adaptations Camouflage Deimatic behaviour Herbivore adaptations to plant defense Mimicry Plant defense against herbivory Predator avoidance in schooling fish

Modelling ecosystems – other components

Population ecology	Abundance Allee effect Depensation Ecological yield Effective population size Intraspecific competition Logistic function Malthusian growth model Maximum sustainable yield Overpopulation in wild animals Overexploitation Population cycle Population dynamics Population modeling Population size Predator–prey (Lotka–Volterra) equations Recruitment Resilience Small population size Stability

Species	Biodiversity Density-dependent inhibition Ecological effects of biodiversity Ecological extinction Endemic species Flagship species Gradient analysis Indicator species Introduced species Invasive species Latitudinal gradients in species diversity Minimum viable population Neutral theory Occupancy-abundance relationship Population viability analysis Priority effect Rapoport's rule Relative abundance distribution Relative species abundance Species diversity Species homogeneity Species richness Species distribution Species-area curve Umbrella species

Species interaction	Antibiosis Biological interaction Commensalism Community ecology Ecological facilitation Interspecific competition Mutualism Storage effect

Spatial ecology	Biogeography Cross-boundary subsidy Ecocline Ecotone Ecotype Disturbance Edge effects Foster's rule Habitat fragmentation Ideal free distribution Intermediate Disturbance Hypothesis Island biogeography Landscape ecology Landscape epidemiology Landscape limnology Metapopulation Patch dynamics r/K selection theory Source–sink dynamics

Niche	Ecological niche Ecological trap Ecosystem engineer Environmental niche modelling Guild Habitat Marine habitats Limiting similarity Niche apportionment models Niche construction Niche differentiation

Other networks	Assembly rules Bateman's principle Bioluminescence Ecological collapse Ecological debt Ecological deficit Ecological energetics Ecological indicator Ecological threshold Ecosystem diversity Emergence Extinction debt Kleiber's law Liebig's law of the minimum Marginal value theorem Thorson's rule Xerosere

Other	Allometry Alternative stable state Balance of nature Biological data visualization Constructal theory Ecocline Ecological economics Ecological footprint Ecological forecasting Ecological humanities Ecological stoichiometry Ecopath Ecosystem based fisheries Endolith Evolutionary ecology Functional ecology Industrial ecology Macroecology Microecosystem Natural environment Regime shift Systems ecology Theoretical ecology

List of ecology topics

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Freshwater ecosystem

Extinction of freshwater fauna

See also

References

Bibliography

External links