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| | Eutrophication | | Eutrophication |
| − | |definition= | + | |definition= (1) An increase in the supply of organic matter.<ref name="NIXON">Nixon, S. W. (1995) Coastal marine eutrophication: a definition, social causes, and future concerns. ''Ophelia'', 41, 199–219.[ISI]</ref> <br> |
| − | The enrichment of water by nutrients, especially nitrogen and/or phosphorus and organic matter, causing an increased growth of algae and higher forms of plant life to produce an unacceptable deviation in structure, function and stability of organisms present in the water and to the quality of water concerned, compared to reference conditions<ref name="And"/> | + | (2) A condition in an aquatic ecosystem where high nutrient concentrations stimulate growth of [[algae]] which leads to imbalanced functioning of the system.<ref> HELCOM webpage, 2006 [http://www.helcom.fi/environment2/eutrophication/en_GB/front/]</ref><br> |
| | + | (3) The enrichment of water by [[nutrient]]s, especially nitrogen and/or phosphorus and organic matter, causing an increased growth of algae and higher forms of plant life to produce an adverse deviation in structure, function and stability of organisms present in the water and to the quality of water concerned, compared to reference conditions.<ref name="And">Andersen, J. H., Schlüter, L. and Ærtebjerg, G. (2006) Coastal eutrophication: recent developments in definitions and implications for monitoring strategies. ''J. Plankton Res''. 28(7): 621-628.</ref> |
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| | + | __NOTOC__ |
| | + | ==Notes== |
| | + | High [[primary production]] boosted by eutrophication usually leads to oxygen depletion caused by decay of organic matter. |
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| − | Eutrophication is an important process involving enrichment of water by excess [[nutrients]]. It can cause serious problems in the coastal zone through disturbance of ecological balances and fisheries, and through interference with recreational activities and quality of life.
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| | + | ==Articles on eutrophication== |
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| − | ==What is eutrophication about?== | + | ===Eutrophication processes=== |
| − | [[image:Baltic.jpg|thumb|right|Fig. 1. Cyanobacteria bloom, Western Baltic, 1997]] | + | * [[Eutrophication in coastal environments]] |
| − | *It’s about '''increased productivity''' (conversion of light and carbon dioxide into living organic matter – a process being limited by ''[[nitrogen]]'' and/or ''[[phosphorus]]'') and unacceptable ecological effects as [[algal blooms]], oxygen depletion, kills of benthic animals and fish | + | * [[What causes eutrophication?]] |
| − | *It’s caused by '''increased inputs''' of nutrients from point sources, activities in the upstream catchment (''e.g.'' losses from agriculture) and atmospheric deposition.
| + | * [[Nutrient conversion in the marine environment]] |
| | + | * [[Which resource limits coastal phytoplankton growth/ abundance: underwater light or nutrients?]] |
| | + | * [[Marine microorganisms]] |
| | + | * [[Marine Plankton]] |
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| | + | ===Eutrophication impacts=== |
| | + | * [[Threats to the coastal zone]] |
| | + | * [[Coastal pollution and impacts]] |
| | + | * [[Possible consequences of eutrophication]] |
| | + | * [[Algal bloom]] |
| | + | * [[Algal bloom dynamics]] |
| | + | * [[Case studies eutrophication]] |
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| | + | ===Eutrophication monitoring=== |
| | + | * [[In situ monitoring of eutrophication]] |
| | + | * [[Plankton remote sensing]] |
| | + | * [[Plankton remote sensing North Sea]] |
| | + | * [[Real-time algae monitoring]] |
| | + | * [[Optical measurements in coastal waters]] |
| | + | * [[Nutrient analysers]] |
| | + | * [[Differentiation of major algal groups by optical absorption signatures]] |
| | + | * [[Sampling tools for the marine environment]] |
| | + | * [[FerryBox - Continuous and automatic water quality observations along transects]] |
| | + | * [[Detecting the unknown - novelty detection of exceptional water reflectance spectra]] |
| | + | * [[The Baltic Algae Watch System - a remote sensing application for monitoring cyanobacterial blooms in the Baltic Sea]] |
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| − | ===What are we really talking about?=== | + | ===Eutrophication modelling=== |
| − | ;Eutrophication : “eu” = “well” or “good”
| + | * [[Coupled hydrodynamic - water quality - ecological modelling]] |
| − | :“trope” = “nourishment”
| + | * [[Nutrient loading of coastal waters]] |
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| | + | ===Eutrophication policy=== |
| | + | * [[OSPAR and eutrophication]] |
| | + | * [[OSPAR eutrophication assessment]] |
| | + | * [[European policy on eutrophication: introduction]] |
| | + | * [[European Context of Nutrient Dynamics]] |
| | + | * [[Eutrophication related monitoring tasks and WFD for coastal waters in Greece]] |
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| − | But is “eutrophication” good?
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| − | *In general: NO … it is actually ”bad” …
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| − | *Too many nutrients in wrong places may cause problems and result in changes in structure, function and stability of the marine ecosystems
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| − | *Eutrophication is ”too much of a good thing”
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| − |
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| − | ==Some definitions:==
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| − | [[image:German Bight.jpg|thumb|right|Fig. 2. Noctiluca milaris bloom, German Bight, 2000]]
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| − | ;Eutrophication : An increase in the supply of organic matter<ref name="NIXON">Nixon, S. W. (1995) Coastal marine eutrophication: a definition, social causes, and future concerns. Ophelia, 41, 199–219.[ISI]</ref>
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| − |
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| − | : A condition in an aquatic ecosystem where high nutrient concentrations stimulate growth of [[algae]] which leads to imbalanced functioning of the system<ref> HELCOM webpage, 2006 [http://www.helcom.fi/environment2/eutrophication/en_GB/front/]</ref>.
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| − | ;Alternative proposal : The enrichment of water by [[nutrients]], especially nitrogen and/or phosphorus and organic matter, causing an increased growth of algae and higher forms of plant life to produce an unacceptable deviation in structure, function and stability of organisms present in the water and to the quality of water concerned, compared to reference conditions<ref name="And">Andersen, J. H., Schlüter, L. and Ærtebjerg, G. (2006) Coastal eutrophication: recent developments in definitions and implications for monitoring strategies. J. Plankton Res. 28(7): 621-628.</ref>
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| − | ==Effects of Eutrophication==
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| − | The different processes and effects of coastal eutrophication are well documented<ref>Cloern, J. (2001) Our evolving conceptual model of the coastal eutrophication problem. Mar. Ecol. Prog. Ser., 210, 223–253.[ISI]</ref> <ref>Conley, D. J., Markager, S., Andersen, J. et al. (2002) Coastal eutrophication and the Danish National Aquatic Monitoring and Assessment Program. Estuaries, 25, 706–719.[Medline]</ref> <ref>Rönnberg, C. and Bonsdorff, E. (2004) Baltic Sea eutrophication: area-specific ecological consequences. Hydrobiologia, 514, 227–241.[CrossRef][ISI]</ref>. and it has been considered as one of the biggest threats to marinne ecosystem health for decades<ref>Ryther and Dunstan, 1971</ref> <ref name="NIXON"/> <ref>Bachmann, R. W., Cloern, J. E., Heckey, R. E. et al. (eds) (2006) Eutrophication of freshwater and marine ecosystems. Limnol. Oceanogr., 51 (1, part 2), 351–800.</ref>.
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| − | [[Image:eutrophicationflow.jpg|600px|thumb|centre|Fig. 3. Eutrophication flow diagram. Source: HELCOM, 2006 <ref name="HELCOM">HELCOM, (2006) Andersen, J (DHI) and Pawlak, J (MEC), Nutrients and Eutrophication in the Baltic Sea – Effects, Causes, Solutions. Baltic Sea Parliamentary Conference.[http://sea.helcom.fi/dps/docs/documents/Monitoring%20and%20Assessment%20Group%20(MONAS)/EUTRO-PRO/EUTRO-PRO%203,%202006/BSPC%20Nutrients%20and%20Eutrophication%20in%20the%20BS.pdf]</ref>
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| − | ]]
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| − | Effects of eutrophication on marine [[ecosystems]] are well known<ref name="HELCOM"/>:
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| − | *algal blooms resulting in green water
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| − | *reduced depth distribution of submerged aquatic vegetation
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| − | *increased growth of nuisance macroalgae
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| − | *increased sedimentation, increased oxygen consumption
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| − | *oxygen depletion in bottom water, and
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| − | *sometimes dead benthic animals and fish.
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| − |
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| − | [[image:koncept.jpg|500px|thumb|centre|Fig. 4. Eutrophication schematic. Source: HELCOM, 2006 <ref name="HELCOM"/>]]
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| − | ===General effects===
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| − | Major effects of eutrophication include structure and function changes in the entire marine ecosystem and a reduction in stability. The following are responses to increased nutrient inputs<ref name="HELCOM"/>:
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| − | #Corresponding increase in nutrient concentrations
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| − | #Change in ratio between dissolved nitrogen and phosphorus in the water: ''DIN:DIP'' ratio. Optimal is 16:1 – called the ''Redfield ratio''. Significantly lower ratio causes potential nitrogen limitation; while a higher ratio leads to phosphorus limitation of phytoplankton primary production.
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| − | ''Primary production'' is usually limited by availability of light and nutrients.
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| − | Nutrient enrichment increase phytoplankton primary production, which increases biomass, which decreases light penetration through water column. Light penetration is measured by Secchi depth - a decreased Secchi depth can reduce colonization depth of macroalgae and [[seagrasses]].
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| − | Responses to nutrient enrichment (pelagic ecosystems) involve a gradual change towards<ref name="HELCOM"/>:
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| − | #Increased [[plankton]]ic [[primary production]] compared to benthic production
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| − | #Dominance of microbial food webs over linear planktonic food chains
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| − | #Dominance of non-siliceous phytoplankton species over diatom species
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| − | #Dominance of gelatinous [[zooplankton]] (jellyfish) over crustacean zooplankton
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| − | Finally, eutrophication issues<ref name="HELCOM"/> are often divided into three groups:
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| − | #Causative factors: inputs, elevated nutrient concentrations, Redfield ratio changes
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| − | #Direct effects: primary producers, namely ''[[phytoplankton]]'' and ''submerged aquatic vegetation''
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| − | #Indirect effects (secondary effects): related to zooplankton, fish and ínvertebrate benthic fauna (animals living on seafloor).
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| − |
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| − | ===Primary and Secondary Effects===
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| − | Some important primary and secondary effects are discussed in the sections below.
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| − | ====Phytoplankton====
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| − | Phytoplankton are at base of pelagic food webs in aquatic systems, have generation times from less that a few days, respond rapidly to nutrient concentration changes, and are often quantified in terms of:
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| − | #Primary production
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| − | #Biomass (chlorophyll-a concentration, or carbon biomass)
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| − | #Bloom frequency
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| − | ====Submerged aquatic vegetation====
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| − | Submerged aquatic venetation are affected by eutrophication through<ref name="HELCOM"/>:
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| − | #Reduced light penetration and shadowing effects from phytoplankton can reduce the depth distribution, biomass, composition and species diversity; and
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| − | #increased growth of filamentous and short lived nuisance macroalgae at cost of long lived species lead to a change in structure of macroalgae community with reduced diversity
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| − | Additionally,
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| − | *Seagrass meadows and perennial macroalgae are important nursery areas for coastal fish populations.
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| − | *Short-lived (annual) nuisance macroalgae are favoured by large nutrient inputs.
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| − | ====Oxygen depletion<ref name="HELCOM"/>====
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| − | Oxygen depletion, or ''[[hypoxia]]'', is a common effect of eutrophication in bottom waters. This effect may be episodic, occuring annually (most common in summer/autumn), persistent, or periodic in the coastal zone.
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| − | *Lethally low oxygen concentrations depend on the species. Fish and crustaceans have higher oxygen requirements; other speices lower.
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| − | *Hypoxic and anoxic (no oxygen) conditions may results in formation and releast of hydrogen sulphide (H<sub>2</sub>S), which is lethal to organisms.
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| − | *Anoxic periods cause release of phophorus from sediments - dissolved inorganic phosphorus (DIP), and ammonium is released under hypoxic conditions. DIP and ammonium in water column can enhance algal blooms.
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| − | *The predicted effect of global warming is to increase hypoxia with increased temperature. A 4 degree temperature increase is projected to results in a doubling of hypoxia in some parts of North Sea.
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| − | *An example of the effect: Eelgrass responds to low oxygen concentrations, and dies off under these conditions (often in combination with high temperatures)
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| − | ====Invertebrate benthic fauna<ref name="HELCOM"/>====
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| − | Invertebrate benthic fauna can cope with oxygen depletion to varying degrees (days – month). If O<sub>2</sub> drops below zero and H<sub>2</sub>S is released all organisms killed immediately. Mobile benthic invertebrates in sediment move to surface when O<sub>2</sub> decreases - there are increased catches of fish and crustaceans during these times. It is difficult to predict when animals will return after eutrophication events. The area affected plays a factor: small areas are recolonised and re-established more quickly
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| − | ===Climate change===
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| − | *Seas are important in element cycling – carbon and nitrogen cycle; phosphorus and silicate cycle
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| − | *Ocean still takes up more carbon than it releases – depositing some in sediments
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| − | ==Solutions==
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| − | Nutrient inputs must be reduced to levels that do not put at risk target values for mitigation of eutrophication. Integrated management strategies should enable characterization of all pressures on water bodies in order to develop a coherent approach to deal with the pressures in a cost effective manner<ref name="HELCOM"/>.
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| − | ==European Coastal Areas==
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| − | The main source of nitrogen to European coastal waters is agricultural runoff discharged into the sea via rivers, identified as originating from sources of ammonia evaporation in animal husbandry and partly from fossil fuel combustion in traffic, industry and households<ref name="ECW">Ærtebjerg, G. et al., Eutrophication in Europe’s Coastal Waters. Topic Report No 7/2001. European Environment Agency. [http://reports.eea.europa.eu/topic_report_2001_7/en]</ref>. For phosphorus the major sources are treated and untreated discharges to the sea from households and industry as well as soil erosion<ref name="ECW"/>.
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| − | ===Baltic Sea in focus===
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| − | Eutrophication seriously affects the Baltic sea marine environment, resulting in algal blooms, reduced water clarity, oxygen reduction and death of bottom animals. The causes behind this are well known<ref name="HELCOM"/>: discharges, losses and emissions of nitrogen and phosphorus to the aquatic environment. Reductions of discharges from municipal wastewater treatment plants and industries have been in focus for many years as have losses and emissions of nitrogen compounds from agriculture and traffic.
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| − | ====Causes in Baltic Sea====
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| − | Human-mediated nutrient enrichment<ref name="HELCOM"/> in the Baltic Sea can be caused by input of nutrients in form of:
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| − | #Direct inputs from point sources (sewage treatment plants, industries)
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| − | #Atmospheric deposition
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| − | #Riverine inputs (from activities in the catchment: eg point sources, agricultural losses, atmospheric deposition, natural background losses (natural erosion and leakage of nutrients from areas without much human activities) and stream, river and lake retention)
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| − | '''Waterborne:''' Agriculture forestry, scattered dwellings, municipanlities, industries, natural background losses.
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| − | '''Airborne:''' Nitrogen compounds emitted to atmosphere:
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| − | *Nitrogen oxides: road transportation, energy combustion, shipping
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| − | *Ammonia emissions: mostly from agriculture.
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| − | *Distant sources
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| − | '''The role of agriculture in nitrogen inputs:'''
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| − | The main source of nitrogen inputs in Baltic Sea is agricultural discharge via rivers, deriving from:
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| − | #Soil cultivation
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| − | #Fertiliser use
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| − | #Use of manure
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| − | #Intensive and uncontrolled agriculture
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| − | ====Aspects of Eutrophication problem in the Baltic sea<ref name="HELCOM"/>====
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| − | *Excessive phytoplankton blooms are major problem – especially of blue-green algae. There are commonly summertime algal blooms in most parts of Gulf of Finland, Gulf of Riga, the Baltic Proper and south-western parts of Baltic Sea
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| − | Problems caused:
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| − | *bathing people can hardly see their feet
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| − | *blue-green algae potentially toxic to humans and animals
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| − | *large mats of drifting algae deposited along shores and decay
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| − | ====Baltic Sea Solutions====
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| − | The following steps are suggested<ref name="HELCOM"/>
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| − | #Establish overall goals and target values
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| − | #Implement relevant measures directly linked to fulfillment of these overall goals and targets
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| − | #Carry out monitoring
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| − | #Conduct assessments
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| − | #Evaluate whether the goals and targets have been fulfilled or not
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| − | '''Main drivers:'''
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| − | *European Directives (see links below)
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| − | *Decisions and recommendations adopted by [http://www.helcom.fi HELCOM]
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| − | *National action plans
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| − | ==EU Directives:==
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| − | :[http://ec.europa.eu/environment/water/water-urbanwaste/directiv.html EC Urban Waster Water Treatment Directive]
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| − | :[http://ec.europa.eu/environment/water/water-nitrates/directiv.html EC Nitrates Directive]
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| − | :[http://ec.europa.eu/environment/water/water-framework/index_en.html EU Water Framework Directive]
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| − | :[http://ec.europa.eu/environment/water/marine.htm Marine Strategy Directive]
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| − | ==See also==
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| − | :[[Theme 4]] - Pollution
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| − | :[[Water quality/pollution]]
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| − | ==External links==
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| − | :[http://www.BSPC.net Baltic Sea Parlimentary Conference ]
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| − | :[http://www.bernet.org/wm125051 BERNET:] Baltic Eutrophication Regional Network
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| − | :[http://www.BONUSportal.org BONUS] for the future of the Baltic Sea
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| − | :[http://www.EEA.europa.eu European Environment Agency ]
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| − | :[http://www.HELCOM.fi HELCOM ]
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| − | :HELCOM Indicator fact sheets:
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| − | ::[http://www.helcom.fi/environment2/ifs/ifs2005/en_GB/inflow water exchange]
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| − | ::[http://www.helcom.fi/environment2/ifs/ifs2005/en_GB/winternutriets winter nutrient concentrations]
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| − | ::[http://www.helcom.fi/environment2/ifs/ifs2005/en_GB/transparency water clarity]
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| − | ::[http://www.helcom.fi/environment2/ifs/ifs2005/en_GB/blooms algal blooms]
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| − | ::[http://www.helcom.fi/environment2/ifs/ifs2005/Chlorophyll-a/en_GB/chlorophyll chlorophyll-a concentrations]
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| − | ::[http://www.helcom.fi/environment2/ifs/ifs2005/en_GB/oxygen_deepbasins hydrography and oxygen in the deep basins]
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| − | :[http://www.MARE.su.se MARE] Research program on Baltic Sea environmental issues
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| − | :[http://www.dmu.dk/International/Water/ National Environment Research Institute (DK) Aquatic page]
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| − | :[http://www2.dmu.dk/1_Viden/2_Miljoe-tilstand/3_vand/4_eutrophication/definition.htm Nutrients and Eutrophication in Danish Marine Waters]
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| − | :[http://www.OSPAR.org OSPAR] For the protection of the marine environment of the north-east Atlantic
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| − | :[http://www.waterforecast.com/defaultUK.asp The Water Forecast]
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| − | :Wikipedia: [http://en.wikipedia.org/wiki/Eutrophication Eutrophication article]
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| − | :[http://www.panda.org/about_wwf/where_we_work/europe/what_we_do/baltics/our_work/index.cfm WWF Baltic Ecoregion Programme]
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| | ==References== | | ==References== |
| − | :[http://sea.helcom.fi/dps/docs/documents/Monitoring%20and%20Assessment%20Group%20(MONAS)/EUTRO-PRO/EUTRO-PRO%203,%202006/BSPC%20Nutrients%20and%20Eutrophication%20in%20the%20BS.pdf Nutrients and Eutrophication in the Baltic Sea - Effects, Causes, Solutions] (HELCOM) - main reference for this article
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| | <references/> | | <references/> |
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| − | [[category:Theme 6]] | + | [[Category:Eutrophication]] |
