Естуар — разлика између измена

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Естуар (лат. aestuarium = залив, ниска обала, aestus = плима, струја) је левкасти залив на ушћу реке широко отворен према мору.^[1] Карактеристичан је за ниске обале на којим је колебање плиме врло велико (од 10 до 20 m). Плимски талас продире ушћем дубоко у реку (на Темзи је око 113 km) и при повлачењу, за време и осеке, носи са собом велику количину трошног материјала. На тај начин се речно корито продубљује и чисти од наноса, а бродовима се отвара пут дубоко у копно. Ако река наталожи на ушћу велику количину седимената (као нпр. Жиронда у Француској), пред естуаром се стварају пешчани спрудови кроз које се при сваком новом наступу плиме отварају пролази. Улаз у такав естуар отежан је због сталне промене положаја пролаза, па је потребна пилотажа. На обалама и на унутрашњем крају естуарског ушћа развили су се велики лучки центри: Лондон (Темза), Хамбург (Лаба), Бордо (Жиронда), Лисабон (Тежо), Буенос Ајрес и Монтевидео (Ла Плата).

Estuaries form a transition zone between river environments and maritime environments and are an example of an ecotone. Estuaries are subject both to marine influences such as tides, waves, and the influx of saline water, and to fluvial influences such as flows of freshwater and sediment. The mixing of seawater and freshwater provides high levels of nutrients both in the water column and in sediment, making estuaries among the most productive natural habitats in the world.^[2] Most existing estuaries formed during the Holocene epoch with the flooding of river-eroded or glacially scoured valleys when the sea level began to rise about 10,000–12,000 years ago.^[3] Estuaries are typically classified according to their geomorphological features or to water-circulation patterns. They can have many different names, such as bays, harbors, lagoons, inlets, or sounds, although some of these water bodies do not strictly meet the above definition of an estuary and could be fully saline.

Many estuaries suffer degeneration from a variety of factors including soil erosion, deforestation, overgrazing, overfishing and the filling of wetlands. Eutrophication may lead to excessive nutrients from sewage and animal wastes; pollutants including heavy metals, polychlorinated biphenyls, radionuclides and hydrocarbons from sewage inputs; and diking or damming for flood control or water diversion.^[3]^[4]

Импликације еутрофикације на ушћа

Effects of eutrophication on biogeochemical cycles

Nitrogen is often the lead cause of eutrophication in estuaries in temperate zones.^[5] During a eutrophication event, biogeochemical feedback decreases the amount of available silica.^[6] These feedbacks also increase the supply of nitrogen and phosphorus, creating conditions where harmful algal blooms can persist. Given the now off-balance nitrogen cycle, estuaries can be driven to phosphorus limitation instead of nitrogen limitation. Estuaries can be severely impacted by an unbalanced phosphorus cycle, as phosphorus interacts with nitrogen and silica availability.

With an abundance of nutrients in the ecosystem, plants and algae overgrow and eventually decompose, which produce a significant amount of carbon dioxide.^[7] While releasing CO2 into the water and atmosphere, these organisms are also intaking all or nearly all of the available oxygen creating a hypoxic environment and unbalanced oxygen cycle.^[8] The excess carbon in the form of CO2 can lead to low pH levels and ocean acidification, which is more harmful for vulnerable coastal regions like estuaries.

Effects of eutrophication on estuarine plants

Eutrophication has been seen to negatively impact many plant communities in estuarine ecosystems.^[9] Salt marshes are a type of ecosystem in some estuaries that have been negatively impacted by eutrophication.^[9] Cordgrass vegetation dominates the salt marsh landscape.^[10] Excess nutrients allow the plants to grow at greater rates in above ground biomass, however less energy is allocated to the roots since nutrients is abundant.^[9]^[11] This leads to a lower biomass in the vegetation below ground which destabilizes the banks of the marsh causing increased rates of erosion.^[9] A similar phenomenon occurs in mangrove swamps, which are another potential ecosystem in estuaries.^[11]^[12] An increase in nitrogen causes an increase in shoot growth and a decrease in root growth.^[11] Weaker root systems cause a mangrove tree to be less resilient in seasons of drought, which can lead to the death of the mangrove.^[11] This shift in above ground and below ground biomass caused by eutrophication could hindered plant success in these ecosystems^[9]^[11].

Effects of eutrophication on estuarine animals

Across all biomes, eutrophication often results in plant death but the impacts do not end there. Plant death alters the entire food web structure which can result in the death of animals within the afflicted biome. Estuaries are hotspots for biodiversity, containing a majority of commercial fish catch, making the impacts of eutrophication that much greater within estuaries.^[13] Some specific estuarine animals feel the effects of eutrophication more strongly than others. One example is the whitefish species from the European Alps.^[14] Eutrophication reduced the oxygen levels in their habitats so greatly that whitefish eggs could not survive, causing local extinctions.^[14] However, some animals, such as carnivorous fish, tend to do well in nutrient poor environments and can benefit from eutrophication.^[15] This can be seen in populations of bass or pikes ^[15].

Effects of eutrophication on human activities

Eutrophication can affect many marine habitats which can lead to economic consequences. The commercial fishing industry relies upon estuaries for approximately 68 percent of their catch by value because of the great biodiversity of this ecosystem.^[16] During an algal bloom, fishermen have noticed a significant increase in the quantity of fish.^[17] A sudden increase in primary productivity causes spikes in fish populations which leads to more oxygen being utilized.^[17] It is the continued deoxygenation of the water that then causes a decline in fish populations. These effects can begin in estuaries and have a wide effect on the surrounding water bodies. In turn, this can decrease fishing industry sales in one area and across the country.^[18] Production in 2016 from recreational and commercial fishing contributes billions of dollars to the United States’ gross domestic product (GDP).^[16] A decrease in production within this industry can affect any of the 1.7 million people the fishing industry employs yearly across the United States.

=Implications for marine life

Estuaries are incredibly dynamic systems, where temperature, salinity, turbidity, depth and flow all change daily in response to the tides. This dynamism makes estuaries highly productive habitats, but also make it difficult for many species to survive year-round. As a result, estuaries large and small experience strong seasonal variation in their fish communities.^[19] In winter, the fish community is dominated by hardy marine residents, and in summer a variety of marine and anadromous fishes move into and out of estuaries, capitalizing on their high productivity.^[20] Estuaries provide a critical habitat to a variety of species that rely on estuaries for life-cycle completion. Pacific Herring (Clupea pallasii) are known to lay their eggs in estuaries and bays, surfperch give birth in estuaries, juvenile flatfish and rockfish migrate to estuaries to rear, and anadromous salmonids and lampreys use estuaries as migration corridors.^[21] Also, migratory bird populations, such as the black-tailed godwit,^[22] rely on estuaries.

Референце

^ Pritchard, D. W. (1967). „What is an estuary: physical viewpoint”. Ур.: Lauf, G. H. Estuaries. A.A.A.S. Publ. 83. Washington, DC. стр. 3—5. hdl:1969.3/24383.
^ McLusky, D. S.; Elliott, M. (2004). The Estuarine Ecosystem: Ecology, Threats and Management. New York: Oxford University Press. ISBN 978-0-19-852508-0.
^ ^а ^б Wolanski, E. (2007). Estuarine Ecohydrology. Amsterdam: Elsevier. ISBN 978-0-444-53066-0.
^ Silva, Sergio; Lowry, Maran; Macaya-Solis, Consuelo; Byatt, Barry; Lucas, Martyn C. (2017). „Can navigation locks be used to help migratory fishes with poor swimming performance pass tidal barrages? A test with lampreys”. Ecological Engineering. 102: 291—302. doi:10.1016/j.ecoleng.2017.02.027 .
^ Howarth, Robert W.; Marino, Roxanne (2006). „Nitrogen as the limiting nutrient for eutrophication in coastal marine ecosystems: Evolving views over three decades”. Limnology and Oceanography (на језику: енглески). 51 (1part2): 364—376. Bibcode:2006LimOc..51..364H. ISSN 0024-3590. S2CID 18144068. doi:10.4319/lo.2006.51.1_part_2.0364.
^ Howarth, Robert; Chan, Francis; Conley, Daniel J; Garnier, Josette; Doney, Scott C; Marino, Roxanne; Billen, Gilles (2011). „Coupled biogeochemical cycles: eutrophication and hypoxia in temperate estuaries and coastal marine ecosystems”. Frontiers in Ecology and the Environment (на језику: енглески). 9 (1): 18—26. ISSN 1540-9295. doi:10.1890/100008.
^ Morales-Williams, Ana M.; Wanamaker, Alan D.; Williams, Clayton J.; Downing, John A. (2021). „Eutrophication Drives Extreme Seasonal CO2 Flux in Lake Ecosystems”. Ecosystems (на језику: енглески). 24 (2): 434—450. ISSN 1432-9840. S2CID 220856626. doi:10.1007/s10021-020-00527-2.
^ Selman, Mindy; Sugg, Zachary; Greenhalgh, Suzie (2008). Eutrophication and Hypoxia in Coastal Areas (на језику: енглески). ISBN 978-1-56973-681-4.
^ ^а ^б ^в ^г ^д Deegan, Linda A.; Johnson, David Samuel; Warren, R. Scott; Peterson, Bruce J.; Fleeger, John W.; Fagherazzi, Sergio; Wollheim, Wilfred M. (2012). „Coastal eutrophication as a driver of salt marsh loss”. Nature. 490 (7420): 388—392. Bibcode:2012Natur.490..388D. ISSN 0028-0836. PMID 23075989. S2CID 4414196. doi:10.1038/nature11533.
^ Donnelly, Jeffrey P.; Bertness, Mark D. (2001). „Rapid shoreward encroachment of salt marsh cordgrass in response to accelerated sea-level rise”. Proceedings of the National Academy of Sciences. 98 (25): 14218—14223. Bibcode:2001PNAS...9814218D. ISSN 0027-8424. PMC 64662 . PMID 11724926. doi:10.1073/pnas.251209298 .
^ ^а ^б ^в ^г ^д Lovelock, Catherine E.; Ball, Marilyn C.; Martin, Katherine C.; C. Feller, Ilka (2009). „Nutrient Enrichment Increases Mortality of Mangroves”. PLOS ONE. 4 (5): e5600. Bibcode:2009PLoSO...4.5600L. ISSN 1932-6203. PMC 2679148 . PMID 19440554. doi:10.1371/journal.pone.0005600 .
^ Guest, Michaela A.; Connolly, Rod M. (2005). „Fine-scale movement and assimilation of carbon in saltmarsh and mangrove habitat by resident animals”. Aquatic Ecology. 38 (4): 599—609. ISSN 1386-2588. S2CID 20771999. doi:10.1007/s10452-005-0442-9.
^ Waltham, Nathan J.; McCann, Jack; Power, Trent; Moore, Matt; Buelow, Christina (2020). „Patterns of fish use in urban estuaries: Engineering maintenance schedules to protect broader seascape habitat”. Estuarine, Coastal and Shelf Science. 238: 106729. Bibcode:2020ECSS..23806729W. ISSN 0272-7714. S2CID 216460098. doi:10.1016/j.ecss.2020.106729.
^ ^а ^б Vonlanthen, P., Bittner, D., Hudson A.G., et al. (2012). Eutrophication causes speciation reversal in whitefish adaptive radiations. Nature. 482, 337-362. DOI: 10.1038/nature0824.
^ ^а ^б Jeppesen, Erik; Peder Jensen, Jens; Søndergaard, Martin; Lauridsen, Torben; Junge Pedersen, Leif; Jensen, Lars (1997), „Top-down control in freshwater lakes: the role of nutrient state, submerged macrophytes and water depth”, Shallow Lakes ’95, Dordrecht: Springer Netherlands, стр. 151—164, ISBN 978-94-010-6382-1, doi:10.1007/978-94-011-5648-6_17, Приступљено 2022-04-20
^ ^а ^б Lellis-Dibble, K.A. (2008). „Estuarine Fish and Shellfish Species in US commercial and Recreational Fisheries: Economic Value as an Incentive to Protect and Restore Estuarine Habitat”. National Oceanic and Atmospheric Administration.
^ ^а ^б Gao, Yang; Lee, Jeong-Yeol (2012-12-30). „Compensatory Responses of Nile Tilapia Oreochromis niloticus under Different Feed-Deprivation Regimes”. Fisheries and Aquatic Sciences. 15 (4): 305—311. ISSN 2234-1749. doi:10.5657/fas.2012.0305.
^ Fay, Gavin; DePiper, Geret; Steinback, Scott; Gamble, Robert J.; Link, Jason S. (2019). „Economic and Ecosystem Effects of Fishing on the Northeast US Shelf”. Frontiers in Marine Science. 6. ISSN 2296-7745. doi:10.3389/fmars.2019.00133 .
^ Osborn, Katherine (децембар 2017). Seasonal fish and invertebrate communities in three northern California estuaries (Теза). Humboldt State University.
^ Allen, Larry G. (1982). „Seasonal abundance, composition and productivity of the littoral fish assemblage in Upper Newport Bay, California” (PDF). Fishery Bulletin. 80 (4): 769—790.
^ Gillanders, BM; Able, KW; Brown, JA; Eggleston, DB; Sheridan, PF (2003). „Evidence of connectivity between juvenile and adult habitats for mobile marine fauna: An important component of nurseries”. Marine Ecology Progress Series. 247: 281—295. Bibcode:2003MEPS..247..281G. JSTOR 24866466. doi:10.3354/meps247281 .
^ Gill, Jennifer A.; Norris, Ken; Potts, Peter M.; Gunnarsson, Tómas Grétar; Atkinson, Philip W.; Sutherland, William J. (2001). „The buffer effect and large-scale population regulation in migratory birds”. Nature. 412 (6845): 436—438. Bibcode:2001Natur.412..436G. PMID 11473317. S2CID 4308197. doi:10.1038/35086568.

Литература

Анђелић М. 1990. Геоморфологија. Београд: Војногеографски институт
Марковић М., Павловић Р., Чупковић Т. 2003. Геоморфологија. Београд: Завод за уџбенике и наставна средства
Пешић Л. 2001. Општа геологија - Егзодинамика. Београд: Рударско-геолошки факултет

Спољашње везе

Animated documentary on Chesapeake Bay NOAA.
„Habitats: Estuaries – Characteristics”. www.onr.navy.mil. Архивирано из оригинала 2009-05-17. г. Приступљено 2009-11-17.
The Estuary Guide (Based on experience and R&D within the UK)

[james-1] Pritchard, D. W. (1967). „What is an estuary: physical viewpoint”. Ур.: Lauf, G. H. Estuaries. A.A.A.S. Publ. 83. Washington, DC. стр. 3—5. hdl:1969.3/24383.

[McLusky-2] McLusky, D. S.; Elliott, M. (2004). The Estuarine Ecosystem: Ecology, Threats and Management. New York: Oxford University Press. ISBN 978-0-19-852508-0.

[Wolanski-3] а ^б Wolanski, E. (2007). Estuarine Ecohydrology. Amsterdam: Elsevier. ISBN 978-0-444-53066-0.

[4] Silva, Sergio; Lowry, Maran; Macaya-Solis, Consuelo; Byatt, Barry; Lucas, Martyn C. (2017). „Can navigation locks be used to help migratory fishes with poor swimming performance pass tidal barrages? A test with lampreys”. Ecological Engineering. 102: 291—302. doi:10.1016/j.ecoleng.2017.02.027 .

[5] Howarth, Robert W.; Marino, Roxanne (2006). „Nitrogen as the limiting nutrient for eutrophication in coastal marine ecosystems: Evolving views over three decades”. Limnology and Oceanography (на језику: енглески). 51 (1part2): 364—376. Bibcode:2006LimOc..51..364H. ISSN 0024-3590. S2CID 18144068. doi:10.4319/lo.2006.51.1_part_2.0364.

[6] Howarth, Robert; Chan, Francis; Conley, Daniel J; Garnier, Josette; Doney, Scott C; Marino, Roxanne; Billen, Gilles (2011). „Coupled biogeochemical cycles: eutrophication and hypoxia in temperate estuaries and coastal marine ecosystems”. Frontiers in Ecology and the Environment (на језику: енглески). 9 (1): 18—26. ISSN 1540-9295. doi:10.1890/100008.

[7] Morales-Williams, Ana M.; Wanamaker, Alan D.; Williams, Clayton J.; Downing, John A. (2021). „Eutrophication Drives Extreme Seasonal CO2 Flux in Lake Ecosystems”. Ecosystems (на језику: енглески). 24 (2): 434—450. ISSN 1432-9840. S2CID 220856626. doi:10.1007/s10021-020-00527-2.

[8] Selman, Mindy; Sugg, Zachary; Greenhalgh, Suzie (2008). Eutrophication and Hypoxia in Coastal Areas (на језику: енглески). ISBN 978-1-56973-681-4.

[:5-9] а ^б ^в ^г ^д Deegan, Linda A.; Johnson, David Samuel; Warren, R. Scott; Peterson, Bruce J.; Fleeger, John W.; Fagherazzi, Sergio; Wollheim, Wilfred M. (2012). „Coastal eutrophication as a driver of salt marsh loss”. Nature. 490 (7420): 388—392. Bibcode:2012Natur.490..388D. ISSN 0028-0836. PMID 23075989. S2CID 4414196. doi:10.1038/nature11533.

[10] Donnelly, Jeffrey P.; Bertness, Mark D. (2001). „Rapid shoreward encroachment of salt marsh cordgrass in response to accelerated sea-level rise”. Proceedings of the National Academy of Sciences. 98 (25): 14218—14223. Bibcode:2001PNAS...9814218D. ISSN 0027-8424. PMC 64662 . PMID 11724926. doi:10.1073/pnas.251209298 .

[:0-11] а ^б ^в ^г ^д Lovelock, Catherine E.; Ball, Marilyn C.; Martin, Katherine C.; C. Feller, Ilka (2009). „Nutrient Enrichment Increases Mortality of Mangroves”. PLOS ONE. 4 (5): e5600. Bibcode:2009PLoSO...4.5600L. ISSN 1932-6203. PMC 2679148 . PMID 19440554. doi:10.1371/journal.pone.0005600 .

[12] Guest, Michaela A.; Connolly, Rod M. (2005). „Fine-scale movement and assimilation of carbon in saltmarsh and mangrove habitat by resident animals”. Aquatic Ecology. 38 (4): 599—609. ISSN 1386-2588. S2CID 20771999. doi:10.1007/s10452-005-0442-9.

[13] Waltham, Nathan J.; McCann, Jack; Power, Trent; Moore, Matt; Buelow, Christina (2020). „Patterns of fish use in urban estuaries: Engineering maintenance schedules to protect broader seascape habitat”. Estuarine, Coastal and Shelf Science. 238: 106729. Bibcode:2020ECSS..23806729W. ISSN 0272-7714. S2CID 216460098. doi:10.1016/j.ecss.2020.106729.

[:1-14] а ^б Vonlanthen, P., Bittner, D., Hudson A.G., et al. (2012). Eutrophication causes speciation reversal in whitefish adaptive radiations. Nature. 482, 337-362. DOI: 10.1038/nature0824.

[:2-15] а ^б Jeppesen, Erik; Peder Jensen, Jens; Søndergaard, Martin; Lauridsen, Torben; Junge Pedersen, Leif; Jensen, Lars (1997), „Top-down control in freshwater lakes: the role of nutrient state, submerged macrophytes and water depth”, Shallow Lakes ’95, Dordrecht: Springer Netherlands, стр. 151—164, ISBN 978-94-010-6382-1, doi:10.1007/978-94-011-5648-6_17, Приступљено 2022-04-20

[:4-16] а ^б Lellis-Dibble, K.A. (2008). „Estuarine Fish and Shellfish Species in US commercial and Recreational Fisheries: Economic Value as an Incentive to Protect and Restore Estuarine Habitat”. National Oceanic and Atmospheric Administration.

[:3-17] а ^б Gao, Yang; Lee, Jeong-Yeol (2012-12-30). „Compensatory Responses of Nile Tilapia Oreochromis niloticus under Different Feed-Deprivation Regimes”. Fisheries and Aquatic Sciences. 15 (4): 305—311. ISSN 2234-1749. doi:10.5657/fas.2012.0305.

[18] Fay, Gavin; DePiper, Geret; Steinback, Scott; Gamble, Robert J.; Link, Jason S. (2019). „Economic and Ecosystem Effects of Fishing on the Northeast US Shelf”. Frontiers in Marine Science. 6. ISSN 2296-7745. doi:10.3389/fmars.2019.00133 .

[19] Osborn, Katherine (децембар 2017). Seasonal fish and invertebrate communities in three northern California estuaries (Теза). Humboldt State University.

[20] Allen, Larry G. (1982). „Seasonal abundance, composition and productivity of the littoral fish assemblage in Upper Newport Bay, California” (PDF). Fishery Bulletin. 80 (4): 769—790.

[21] Gillanders, BM; Able, KW; Brown, JA; Eggleston, DB; Sheridan, PF (2003). „Evidence of connectivity between juvenile and adult habitats for mobile marine fauna: An important component of nurseries”. Marine Ecology Progress Series. 247: 281—295. Bibcode:2003MEPS..247..281G. JSTOR 24866466. doi:10.3354/meps247281 .

[22] Gill, Jennifer A.; Norris, Ken; Potts, Peter M.; Gunnarsson, Tómas Grétar; Atkinson, Philip W.; Sutherland, William J. (2001). „The buffer effect and large-scale population regulation in migratory birds”. Nature. 412 (6845): 436—438. Bibcode:2001Natur.412..436G. PMID 11473317. S2CID 4308197. doi:10.1038/35086568.

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@@ Ред 1: / Ред 1: @@
+{{Short description|Делимично затворено приобално тело бочате воде}}{{рут}}
 {{Теме океанских станишта}}
-[[Датотека:Estuary-mouth.jpg|мини|десно|250п|Естуар]]
-[[Датотека:France-Gironde-bec d'ambès.jpg|мини|десно|250п|Естуар Жиронде на југу Француске]]
-'''Естуар''' ({{јез-лат|aestuarium}} = залив, ниска обала, ''-{aestus}-'' = плима, струја) је левкасти [[залив]] на [[ушће|ушћу]] реке широко отворен према мору. Карактеристичан је за ниске обале на којим је колебање плиме врло велико (од 10 до 20 -{m}-).
-[[Плима|Плимски]] талас продире ушћем дубоко у реку (на [[Темза|Темзи]] је око 113 -{km}-) и при повлачењу, за време  и [[осека|осеке]], носи са собом велику количину трошног материјала. На тај начин се речно корито продубљује и чисти од наноса, а [[брод]]овима се отвара пут дубоко у копно.
+'''Естуар''' ({{јез-лат|aestuarium}} = залив, ниска обала, ''-{aestus}-'' = плима, струја) је левкасти [[залив]] на [[ушће|ушћу]] реке широко отворен према мору.<ref name="james">{{cite book |last=Pritchard |first=D. W. |year=1967 |chapter= What is an estuary: physical viewpoint |pages=3–5 |editor-first=G. H. |editor-last=Lauf |title= Estuaries |series=A.A.A.S. Publ. |volume=83 |location=Washington, DC |hdl=1969.3/24383 }}</ref> Карактеристичан је за ниске обале на којим је колебање плиме врло велико (од 10 до 20 -{m}-). [[Плима|Плимски]] талас продире ушћем дубоко у реку (на [[Темза|Темзи]] је око 113 -{km}-) и при повлачењу, за време  и [[осека|осеке]], носи са собом велику количину трошног материјала. На тај начин се речно корито продубљује и чисти од наноса, а [[брод]]овима се отвара пут дубоко у копно. Ако река наталожи на ушћу велику количину седимената (као нпр. [[Жиронда]] у [[Француска|Француској]]), пред естуаром се стварају пешчани [[спруд]]ови кроз које се при сваком новом наступу [[плима|плиме]] отварају пролази. Улаз у такав естуар отежан је због сталне промене положаја пролаза, па је потребна пилотажа. На обалама и на унутрашњем крају естуарског ушћа развили су се велики [[лука|лучки]] центри: [[Лондон]] ([[Темза]]), [[Хамбург]] ([[Лаба (река)|Лаба]]), [[Бордо]] (Жиронда), [[Лисабон]] ([[Тахо (река)|Тежо]]), [[Буенос Ајрес]] и [[Монтевидео]] ([[Рио де ла Плата (естуар)|Ла Плата]]).
+[[Датотека:Estuary-mouth.jpg|мини|лево|250п|Естуар]]
-Ако река наталожи на ушћу велику количину седимената (као нпр. [[Жиронда]] у [[Француска|Француској]]), пред естуаром се стварају пешчани [[спруд]]ови кроз које се при сваком новом наступу [[плима|плиме]] отварају пролази. Улаз у такав естуар отежан је због сталне промене положаја пролаза, па је потребна пилотажа.
+[[Датотека:France-Gironde-bec d'ambès.jpg|мини|лево|250п|Естуар Жиронде на југу Француске]]
+Estuaries form a transition zone between river environments and maritime environments and are an example of an [[ecotone]]. Estuaries are subject both to marine influences such as [[tides]], waves, and the influx of saline water, and to fluvial influences such as flows of freshwater and sediment. The mixing of seawater and freshwater provides high levels of nutrients both in the water column and in [[sediment]], making estuaries among the most productive natural habitats in the world.<ref name="McLusky">{{cite book |last1=McLusky |first1=D. S. |last2=Elliott |first2=M. |year=2004 |title=The Estuarine Ecosystem: Ecology, Threats and Management |location=New York |publisher=Oxford University Press |isbn=978-0-19-852508-0 }}</ref> Most existing estuaries formed during the [[Holocene]] epoch with the flooding of river-eroded or glacially scoured valleys when the sea level began to rise about 10,000–12,000 years ago.<ref name="Wolanski">{{cite book |last=Wolanski |first=E. |year=2007 |title=Estuarine Ecohydrology |location=Amsterdam |publisher=Elsevier |isbn=978-0-444-53066-0 }}</ref> Estuaries are typically classified according to their [[geomorphology|geomorphological]] features or to water-circulation patterns. They can have many different names, such as [[bay]]s, [[harbor]]s, [[lagoon]]s, [[inlet]]s, or [[Sound (geography)|sound]]s, although some of these water bodies do not strictly meet the above definition of an estuary and could be fully saline.
+Many estuaries suffer [[Habitat destruction|degeneration]] from a variety of factors including [[soil erosion]], [[deforestation]], [[overgrazing]], [[overfishing]] and the filling of wetlands. [[Eutrophication]] may lead to excessive nutrients from sewage and animal wastes; pollutants including [[heavy metals]], [[polychlorinated biphenyl]]s, [[radionuclide]]s and [[hydrocarbon]]s from sewage inputs; and diking or damming for [[flood control]] or water diversion.<ref name="Wolanski"/><ref>{{cite journal |doi=10.1016/j.ecoleng.2017.02.027 |title=Can navigation locks be used to help migratory fishes with poor swimming performance pass tidal barrages? A test with lampreys |journal=Ecological Engineering |volume=102 |pages=291–302 |year=2017 |last1=Silva |first1=Sergio |last2=Lowry |first2=Maran |last3=Macaya-Solis |first3=Consuelo |last4=Byatt |first4=Barry |last5=Lucas |first5=Martyn C. |doi-access=free }}</ref>
-На обалама и на унутрашњем крају естуарског ушћа развили су се велики [[лука|лучки]] центри: [[Лондон]] ([[Темза]]), [[Хамбург]] ([[Лаба (река)|Лаба]]), [[Бордо]] (Жиронда), [[Лисабон]] ([[Тахо (река)|Тежо]]), [[Буенос Ајрес]] и [[Монтевидео]] ([[Рио де ла Плата (естуар)|Ла Плата]]).
+== Импликације еутрофикације на ушћа ==
+=== Effects of eutrophication on biogeochemical cycles ===
+Nitrogen is often the lead cause of [[eutrophication]] in estuaries in temperate zones.<ref>{{Cite journal |last1=Howarth |first1=Robert W. |last2=Marino |first2=Roxanne |date=2006 |title=Nitrogen as the limiting nutrient for eutrophication in coastal marine ecosystems: Evolving views over three decades |url=https://onlinelibrary.wiley.com/doi/abs/10.4319/lo.2006.51.1_part_2.0364 |journal=Limnology and Oceanography |language=en |volume=51 |issue=1part2 |pages=364–376 |doi=10.4319/lo.2006.51.1_part_2.0364 |bibcode=2006LimOc..51..364H |s2cid=18144068 |issn=0024-3590}}</ref> During a eutrophication event, biogeochemical feedback decreases the amount of available [[Silica cycle|silica]].<ref>{{Cite journal |last1=Howarth |first1=Robert |last2=Chan |first2=Francis |last3=Conley |first3=Daniel J |last4=Garnier |first4=Josette |last5=Doney |first5=Scott C |last6=Marino |first6=Roxanne |last7=Billen |first7=Gilles |date=2011 |title=Coupled biogeochemical cycles: eutrophication and hypoxia in temperate estuaries and coastal marine ecosystems |url=https://onlinelibrary.wiley.com/doi/abs/10.1890/100008 |journal=Frontiers in Ecology and the Environment |language=en |volume=9 |issue=1 |pages=18–26 |doi=10.1890/100008 |issn=1540-9295}}</ref> These feedbacks also increase the supply of [[Nitrogen cycle|nitrogen]] and phosphorus, creating conditions where harmful algal blooms can persist. Given the now off-balance [[nitrogen cycle]], estuaries can be driven to [[Phosphorus cycle|phosphorus]] limitation instead of nitrogen limitation. Estuaries can be severely impacted by an unbalanced phosphorus cycle, as phosphorus interacts with nitrogen and silica availability.
+With an abundance of nutrients in the ecosystem, plants and algae overgrow and eventually decompose, which produce a significant amount of carbon dioxide.<ref>{{Cite journal |last1=Morales-Williams |first1=Ana M. |last2=Wanamaker |first2=Alan D. |last3=Williams |first3=Clayton J. |last4=Downing |first4=John A. |date=2021 |title=Eutrophication Drives Extreme Seasonal CO2 Flux in Lake Ecosystems |url=https://link.springer.com/10.1007/s10021-020-00527-2 |journal=Ecosystems |language=en |volume=24 |issue=2 |pages=434–450 |doi=10.1007/s10021-020-00527-2 |s2cid=220856626 |issn=1432-9840}}</ref> While releasing CO2 into the water and atmosphere, these organisms are also intaking all or nearly all of the available oxygen creating a [[Dead zone (ecology)|hypoxic]] environment and unbalanced [[oxygen cycle]].<ref>{{Cite book |last1=Selman |first1=Mindy |url=https://www.wri.org/research/eutrophication-and-hypoxia-coastal-areas |title=Eutrophication and Hypoxia in Coastal Areas |last2=Sugg |first2=Zachary |last3=Greenhalgh |first3=Suzie |date=2008 |isbn=978-1-56973-681-4 |language=en}}</ref> The excess carbon in the form of CO2 can lead to low pH levels and [[ocean acidification]], which is more harmful for vulnerable coastal regions like estuaries.
+=== Effects of eutrophication on estuarine plants ===
+[[File:Wood_storks_wading_in_a_marsh.jpg|thumb|250п|A salt marsh with wood storks wading.]]
+[[Eutrophication]] has been seen to negatively impact many plant communities in estuarine [[Ecosystem|ecosystems]].<ref name=":5">{{Cite journal |last1=Deegan |first1=Linda A. |last2=Johnson |first2=David Samuel |last3=Warren |first3=R. Scott |last4=Peterson |first4=Bruce J. |last5=Fleeger |first5=John W. |last6=Fagherazzi |first6=Sergio |last7=Wollheim |first7=Wilfred M. |date=2012 |title=Coastal eutrophication as a driver of salt marsh loss |url=http://dx.doi.org/10.1038/nature11533 |journal=Nature |volume=490 |issue=7420 |pages=388–392 |doi=10.1038/nature11533 |pmid=23075989 |bibcode=2012Natur.490..388D |s2cid=4414196 |issn=0028-0836}}</ref> [[Salt marsh|Salt marshes]] are a type of ecosystem in some estuaries that have been negatively impacted by eutrophication.<ref name=":5" /> [[Spartina|Cordgrass]] vegetation dominates the salt marsh landscape.<ref>{{Cite journal |last1=Donnelly |first1=Jeffrey P. |last2=Bertness |first2=Mark D. |date=2001 |title=Rapid shoreward encroachment of salt marsh cordgrass in response to accelerated sea-level rise |journal=Proceedings of the National Academy of Sciences |volume=98 |issue=25 |pages=14218–14223 |doi=10.1073/pnas.251209298 |pmid=11724926 |pmc=64662 |bibcode=2001PNAS...9814218D |issn=0027-8424|doi-access=free }}</ref> Excess nutrients allow the plants to grow at greater rates in above ground biomass, however less energy is allocated to the roots since nutrients is abundant.<ref name=":5" /><ref name=":0">{{Cite journal |last1=Lovelock |first1=Catherine E. |last2=Ball |first2=Marilyn C. |last3=Martin |first3=Katherine C. |last4=C. Feller |first4=Ilka |date=2009 |title=Nutrient Enrichment Increases Mortality of Mangroves |journal=PLOS ONE |volume=4 |issue=5 |pages=e5600 |doi=10.1371/journal.pone.0005600 |pmid=19440554 |pmc=2679148 |bibcode=2009PLoSO...4.5600L |issn=1932-6203|doi-access=free }}</ref> This leads to a lower [[Biomass (ecology)|biomass]] in the vegetation below ground which destabilizes the banks of the marsh causing increased rates of [[erosion]].<ref name=":5" /> A similar phenomenon occurs in [[Mangrove forest|mangrove swamps]], which are another potential ecosystem in estuaries.<ref name=":0" /><ref>{{Cite journal |last1=Guest |first1=Michaela A. |last2=Connolly |first2=Rod M. |date=2005 |title=Fine-scale movement and assimilation of carbon in saltmarsh and mangrove habitat by resident animals |url=http://dx.doi.org/10.1007/s10452-005-0442-9 |journal=Aquatic Ecology |volume=38 |issue=4 |pages=599–609 |doi=10.1007/s10452-005-0442-9 |s2cid=20771999 |issn=1386-2588}}</ref> An increase in nitrogen causes an increase in shoot growth and a decrease in root growth.<ref name=":0" /> Weaker root systems cause a mangrove tree to be less resilient in seasons of drought, which can lead to the death of the mangrove.<ref name=":0" /> This shift in above ground and below ground biomass caused by eutrophication could hindered plant success in these ecosystems<ref name=":5" /><ref name=":0" />.
+=== Effects of eutrophication on estuarine animals ===
+[[File:Whitefish, from the Fish from American Waters series (N8) for Allen & Ginter Cigarettes Brands MET DP830737.jpg|thumb|лево|250п|Example of a whitefish]]
+Across all biomes, [[eutrophication]] often results in plant death but the impacts do not end there. Plant death alters the entire food web structure which can result in the death of animals within the afflicted [[biome]]. Estuaries are hotspots for [[biodiversity]], containing a majority of commercial fish catch, making the impacts of eutrophication that much greater within estuaries.<ref>{{Cite journal |last1=Waltham |first1=Nathan J. |last2=McCann |first2=Jack |last3=Power |first3=Trent |last4=Moore |first4=Matt |last5=Buelow |first5=Christina |date=2020 |title=Patterns of fish use in urban estuaries: Engineering maintenance schedules to protect broader seascape habitat |url=http://dx.doi.org/10.1016/j.ecss.2020.106729 |journal=[[Estuarine, Coastal and Shelf Science]] |volume=238 |pages=106729 |doi=10.1016/j.ecss.2020.106729 |bibcode=2020ECSS..23806729W |s2cid=216460098 |issn=0272-7714}}</ref> Some specific estuarine animals feel the effects of eutrophication more strongly than others. One example is the whitefish species from the [[Alps|European Alps]].<ref name=":1">[https://ec.europa.eu/environment/integration/research/newsalert/pdf/290na1_en.pdf Vonlanthen, P., Bittner, D., Hudson A.G., et al. (2012). Eutrophication causes speciation reversal in whitefish adaptive radiations. Nature. 482, 337-362. DOI: 10.1038/nature0824.]</ref> Eutrophication reduced the oxygen levels in their habitats so greatly that whitefish eggs could not survive, causing local extinctions.<ref name=":1" /> However, some animals, such as carnivorous fish, tend to do well in nutrient poor environments and can benefit from eutrophication.<ref name=":2">{{Citation |last1=Jeppesen |first1=Erik |title=Top-down control in freshwater lakes: the role of nutrient state, submerged macrophytes and water depth |date=1997 |url=http://dx.doi.org/10.1007/978-94-011-5648-6_17 |work=Shallow Lakes ’95 |pages=151–164 |place=Dordrecht |publisher=Springer Netherlands |isbn=978-94-010-6382-1 |access-date=2022-04-20 |last2=Peder Jensen |first2=Jens |last3=Søndergaard |first3=Martin |last4=Lauridsen |first4=Torben |last5=Junge Pedersen |first5=Leif |last6=Jensen |first6=Lars|doi=10.1007/978-94-011-5648-6_17 }}</ref> This can be seen in populations of bass or pikes <ref name=":2" />.
+=== Effects of eutrophication on human activities ===
+[[File:Fishing_boat_at_Wrangell_Harbor.jpg|thumb|250п|Commercial fishing boat]]
+Eutrophication can affect many marine habitats which can lead to economic consequences. The commercial fishing industry relies upon estuaries for approximately 68 percent of their catch by value because of the great biodiversity of this ecosystem.<ref name=":4">{{Cite journal |last=Lellis-Dibble |first=K.A. |date=2008 |title=Estuarine Fish and Shellfish Species in US commercial and Recreational Fisheries: Economic Value as an Incentive to Protect and Restore Estuarine Habitat |journal=National Oceanic and Atmospheric Administration}}</ref> During an [[algal bloom]], fishermen have noticed a significant increase in the quantity of fish.<ref name=":3">{{Cite journal |last1=Gao |first1=Yang |last2=Lee |first2=Jeong-Yeol |date=2012-12-30 |title=Compensatory Responses of Nile Tilapia Oreochromis niloticus under Different Feed-Deprivation Regimes |url=http://dx.doi.org/10.5657/fas.2012.0305 |journal=Fisheries and Aquatic Sciences |volume=15 |issue=4 |pages=305–311 |doi=10.5657/fas.2012.0305 |issn=2234-1749}}</ref> A sudden increase in primary productivity causes spikes in fish populations which leads to more oxygen being utilized.<ref name=":3" /> It is the continued deoxygenation of the water that then causes a decline in fish populations. These effects can begin in estuaries and have a wide effect on the surrounding water bodies.  In turn, this can decrease fishing industry sales in one area and across the country.<ref>{{Cite journal |last1=Fay |first1=Gavin |last2=DePiper |first2=Geret |last3=Steinback |first3=Scott |last4=Gamble |first4=Robert J. |last5=Link |first5=Jason S. |date=2019 |title=Economic and Ecosystem Effects of Fishing on the Northeast US Shelf |journal=Frontiers in Marine Science |volume=6 |doi=10.3389/fmars.2019.00133 |issn=2296-7745|doi-access=free }}</ref> Production in 2016 from recreational and commercial fishing contributes billions of dollars to the United States’ gross domestic product (GDP).<ref name=":4" /> A decrease in production within this industry can affect any of the 1.7 million people the fishing industry employs yearly across the United States.
+===Implications for marine life==
+Estuaries are incredibly dynamic systems, where temperature, salinity, turbidity, depth and flow all change daily in response to the tides. This dynamism makes estuaries highly productive habitats, but also make it difficult for many species to survive year-round. As a result, estuaries large and small experience strong seasonal variation in their fish communities.<ref>{{cite thesis|last=Osborn|first=Katherine|title=Seasonal fish and invertebrate communities in three northern California estuaries|date=December 2017|degree=M.S.|publisher=Humboldt State University|url=https://digitalcommons.humboldt.edu/etd/101/}}</ref> In winter, the fish community is dominated by hardy marine residents, and in summer a variety of marine and anadromous fishes move into and out of estuaries, capitalizing on their high productivity.<ref>{{Cite journal|last=Allen|first=Larry G.|date=1982|title=Seasonal abundance, composition and productivity of the littoral fish assemblage in Upper Newport Bay, California|url=https://www.st.nmfs.noaa.gov/spo/FishBull/80-4/allen.pdf|journal=Fishery Bulletin|volume=80|issue=4|pages=769–790}}</ref> Estuaries provide a critical habitat to a variety of species that rely on estuaries for life-cycle completion. Pacific Herring (''Clupea pallasii'') are known to lay their eggs in estuaries and bays, surfperch give birth in estuaries, juvenile flatfish and rockfish migrate to estuaries to rear, and [[Fish migration|anadromous]] [[Salmonidae|salmonids]] and [[lamprey]]s use estuaries as migration corridors.<ref>{{cite journal |doi=10.3354/meps247281 |jstor=24866466 |title=Evidence of connectivity between juvenile and adult habitats for mobile marine fauna: An important component of nurseries |journal=Marine Ecology Progress Series |volume=247 |pages=281–295 |year=2003 |last1=Gillanders |first1=BM |last2=Able |first2=KW |last3=Brown |first3=JA |last4=Eggleston |first4=DB |last5=Sheridan |first5=PF |bibcode=2003MEPS..247..281G |doi-access=free }}</ref> Also, [[Bird migration|migratory]] bird populations, such as the [[black-tailed godwit]],<ref>{{cite journal |doi=10.1038/35086568 |pmid=11473317 |title=The buffer effect and large-scale population regulation in migratory birds |journal=Nature |volume=412 |issue=6845 |pages=436–438 |year=2001 |last1=Gill |first1=Jennifer A. |last2=Norris |first2=Ken |last3=Potts |first3=Peter M. |last4=Gunnarsson |first4=Tómas Grétar |last5=Atkinson |first5=Philip W. |last6=Sutherland |first6=William J. |bibcode=2001Natur.412..436G |s2cid=4308197 }}</ref> rely on estuaries.
+== Референце ==
+{{Reflist|}}
 == Литература ==
+{{Refbegin|30em}}
-# Анђелић М. 1990. ''Геоморфологија''. Београд: Војногеографски институт
-# Марковић М., Павловић Р., Чупковић Т. 2003. ''Геоморфологија''. Београд: Завод за уџбенике и наставна средства
+* Анђелић М. 1990. ''Геоморфологија''. Београд: Војногеографски институт
+* Марковић М., Павловић Р., Чупковић Т. 2003. ''Геоморфологија''. Београд: Завод за уџбенике и наставна средства
-# Пешић Л. 2001. ''Општа геологија - Егзодинамика''. Београд: Рударско-геолошки факултет
+* Пешић Л. 2001. ''Општа геологија - Егзодинамика''. Београд: Рударско-геолошки факултет
+{{Refend}}
 == Спољашње везе ==
-{{Commonscat|Estuaries}}
+{{Commons category|Estuaries}}
+{{Wiktionary|estuary}}
+* [https://web.archive.org/web/20101023203928/http://ecopath.org/LifeInTheChesapeakeBay/ Animated documentary on Chesapeake Bay] [[NOAA]].
+* {{cite web
+ |url         = http://www.onr.navy.mil/Focus/ocean/habitats/estuaries1.htm
+ |title       = Habitats: Estuaries – Characteristics
+ |publisher   = www.onr.navy.mil
+ |access-date  = 2009-11-17
+ |url-status     = dead
+ |archive-url  = https://web.archive.org/web/20090517130442/http://www.onr.navy.mil/focus/ocean/habitats/estuaries1.htm
+ |archive-date = 2009-05-17
+}}
+* [http://www.estuary-guide.net The Estuary Guide (Based on experience and R&D within the UK)]
-{{клица-геологија}}
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