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109-565: NOWPAP covers the marine and coastal zone ranging from 33°N to 52°N latitude, and from 121°E to 143°E longitude. Being one of the most densely populated parts of the world, where people are particularly dependent on the sea for their food and livelihood, the region is suffering from enormous pressures and demands on its marine environment. Thus people and ecosystems are under severe threat mainly from land-based activities and sources of pollution. Industrial effluents, untreated municipal sewage and run-off of agricultural pesticides and nutrients entering

218-661: A 90% removal efficiency. Still, some targeted point sources did not show a decrease in runoff despite reduction efforts. Harmful algal bloom A harmful algal bloom ( HAB ), or excessive algae growth , is an algal bloom that causes negative impacts to other organisms by production of natural algae-produced toxins , water deoxygenation , mechanical damage to other organisms, or by other means. HABs are sometimes defined as only those algal blooms that produce toxins, and sometimes as any algal bloom that can result in severely lower oxygen levels in natural waters, killing organisms in marine or fresh waters . Blooms can last from

327-567: A HAB alert for Newman Lake following tests showing potentially harmful toxicity levels for cyanobacteria, while in the same month record-high levels of microcystins were reported leading to an extended 'Do Not Drink' advisory for 280 households at Clear Lake , California's second-largest freshwater lake. Water conditions in Florida, meanwhile, continue to deteriorate under increasing nutrient inflows, causing severe HAB events in both freshwater and marine areas. HABs also cause harm by blocking

436-525: A HAB event may cause asthma attacks or lead to other respiratory ailments. In 2018 agricultural officials in Utah worried that even crops could become contaminated if irrigated with toxic water, although they admit that they can't measure contamination accurately because of so many variables in farming. They issued warnings to residents, however, out of caution. Persons are generally warned not to enter or drink water from algal blooms, or let their pets swim in

545-432: A bloom nearby is not recommended. Potent toxins are accumulated in shellfish that feed on the algae. If the shellfish are consumed, various types of poisoning may result. These include amnesic shellfish poisoning (ASP), diarrhetic shellfish poisoning , neurotoxic shellfish poisoning , and paralytic shellfish poisoning . A 2002 study has shown that algal toxins may be the cause for as many as 60,000 intoxication cases in

654-402: A bloom reduces oxygen saturation during the night by respiration. And when the algae eventually die off, the microbes which decompose the dead algae use up even more oxygen, which in turn causes more fish to die or leave the area. When oxygen continues to be depleted by blooms it can lead to hypoxic dead zones , where neither fish nor plants are able to survive. These dead zones in the case of

763-424: A concentration of 1,000 algae cells/ml, while in dense blooms they can measure over 200,000/ml. Diatoms produce domoic acid , another neurotoxin, which can cause seizures in higher vertebrates and birds as it concentrates up the food chain. Domoic acid readily accumulates in the bodies of shellfish , sardines , and anchovies , which if then eaten by sea lions , otters , cetaceans , birds or people, can affect

872-459: A cyanobacteria-dominated system characterized by seasonal HABs. As more wastewater treatment infrastructure is built, more treated wastewater is returned to the natural water system, leading to a significant increase in these residual nutrients. Residual nutrients combine with nutrients from other sources to increase the sediment nutrient stockpile that is the driving force behind phase shifts to entrenched eutrophic conditions. This contributes to

981-455: A different location. Australia in 2016 also had to cut off water to farmers. Alan Steinman of Grand Valley State University has explained that among the major causes for the algal blooms in general, and Lake Erie specifically, is because blue-green algae thrive with high nutrients, along with warm and calm water. Lake Erie is more prone to blooms because it has a high nutrient level and is shallow, which causes it to warm up more quickly during

1090-547: A factor, since phytoplankton can grow at different rates depending on the relative abundance of these substances (e.g. ammonia , urea , nitrate ion). A variety of other nutrient sources can also play an important role in affecting algal bloom formation, including iron, silica or carbon. Coastal water pollution produced by humans (including iron fertilization) and systematic increase in sea water temperature have also been suggested as possible contributing factors in HABs. Among

1199-527: A few days to many months. After the bloom dies, the microbes that decompose the dead algae use up more of the oxygen, generating a " dead zone " which can cause fish die-offs . When these zones cover a large area for an extended period of time, neither fish nor plants are able to survive. Harmful algal blooms in marine environments are often called "red tides". It is sometimes unclear what causes specific HABs as their occurrence in some locations appears to be entirely natural, while in others they appear to be

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1308-521: A few decades. After a 2014 HAB incident in Monterey Bay , California, health officials warned people not to eat certain parts of anchovy, sardines, or crab caught in the bay. In 2015 most shellfish fisheries in Washington, Oregon and California were shut down because of high concentrations of toxic domoic acid in shellfish. People have been warned that inhaling vapors from waves or wind during

1417-409: A foam, scum, or mat on or just below the surface of water and can take on various colors depending on their pigments. Cyanobacteria blooms in freshwater lakes or rivers may appear bright green, often with surface streaks that look like floating paint. Cyanobacterial blooms are a global problem. Most blooms occur in warm waters with excessive nutrients. The harmful effects from such blooms are due to

1526-400: A food source for zooplankton . Thus a self-sustaining biological process can take place to generate primary food source for the phytoplankton and zooplankton depending on the availability of adequate dissolved oxygen in the water body. Enhanced growth of aquatic vegetation, phytoplankton and algal blooms disrupts normal functioning of the ecosystem, causing a variety of problems such as

1635-550: A healthy norm of living, some of which are as follows: There are multiple different ways to fix cultural eutrophication with raw sewage being a point source of pollution. For example, sewage treatment plants can be upgraded for biological nutrient removal so that they discharge much less nitrogen and phosphorus to the receiving water body. However, even with good secondary treatment , most final effluents from sewage treatment works contain substantial concentrations of nitrogen as nitrate, nitrite or ammonia. Removal of these nutrients

1744-437: A lack of oxygen which is needed for fish and shellfish to survive. The growth of dense algae in surface waters can shade the deeper water and reduce the viability of benthic shelter plants with resultant impacts on the wider ecosystem. Eutrophication also decreases the value of rivers, lakes and aesthetic enjoyment. Health problems can occur where eutrophic conditions interfere with drinking water treatment . Phosphorus

1853-441: A natural process and occurs naturally through the gradual accumulation of sediment and nutrients. Naturally, eutrophication is usually caused by the natural accumulation of nutrients from dissolved phosphate minerals and dead plant matter in water. Natural eutrophication has been well-characterized in lakes. Paleolimnologists now recognise that climate change, geology, and other external influences are also critical in regulating

1962-428: A natural result of the movement of certain ocean currents) while in others they appear to be a result of increased nutrient pollution from human activities. The growth of marine phytoplankton is generally limited by the availability of nitrates and phosphates , which can be abundant in agricultural run-off as well as coastal upwelling zones. Other factors such as iron-rich dust influx from large desert areas such as

2071-463: A normally limiting nutrient . This process causes shifts in the species composition of ecosystems. For instance, an increase in nitrogen might allow new, competitive species to invade and out-compete original inhabitant species. This has been shown to occur in New England salt marshes . In Europe and Asia, the common carp frequently lives in naturally eutrophic or hypereutrophic areas, and

2180-415: A predictable seasonal occurrence resulting from coastal upwelling, a natural result of the movement of certain ocean currents. The growth of marine phytoplankton (both non-toxic and toxic) is generally limited by the availability of nitrates and phosphates, which can be abundant in coastal upwelling zones as well as in agricultural run-off. The type of nitrates and phosphates available in the system are also

2289-655: A result of human activities. In certain locations there are links to particular drivers like nutrients, but HABs have also been occurring since before humans started to affect the environment. HABs are induced by eutrophication , which is an overabundance of nutrients in the water. The two most common nutrients are fixed nitrogen ( nitrates , ammonia , and urea ) and phosphate . The excess nutrients are emitted by agriculture , industrial pollution, excessive fertilizer use in urban/suburban areas, and associated urban runoff . Higher water temperature and low circulation also contribute. HABs can cause significant harm to animals,

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2398-505: A set of tools to minimize causes of eutrophication. Nonpoint sources of pollution are the primary contributors to eutrophication, and their effects can be minimized through common agricultural practices. Reducing the amount of pollutants that reach a watershed can be achieved through the protection of its forest cover, reducing the amount of erosion leeching into a watershed. Also, through the efficient, controlled use of land using sustainable agricultural practices to minimize land degradation ,

2507-498: A simple reversal of inputs since there are sometimes several stable but very different ecological states. Recovery of eutrophicated lakes is slow, often requiring several decades. In environmental remediation , nutrient removal technologies include biofiltration , which uses living material to capture and biologically degrade pollutants. Examples include green belts, riparian areas, natural and constructed wetlands, and treatment ponds. The National Oceanic Atmospheric Admiration in

2616-399: A status report. While no particular cause of HABs has been found, many different factors can contribute to their presence. These factors can include water pollution , which originates from sources such as human sewage and agricultural runoff . The occurrence of HABs in some locations appears to be entirely natural (algal blooms are a seasonal occurrence resulting from coastal upwelling,

2725-421: A threat to humans. An example of algal toxins working their way into humans is the case of shellfish poisoning. Biotoxins created during algal blooms are taken up by shellfish ( mussels , oysters ), leading to these human foods acquiring the toxicity and poisoning humans. Examples include paralytic , neurotoxic, and diarrhoetic shellfish poisoning. Other marine animals can be vectors for such toxins, as in

2834-552: Is a natural phenomenon, but the exact cause or combination of factors that result in a HAB event are not necessarily known. However, three key natural factors are thought to play an important role in a bloom - salinity, temperature, and wind. HABs cause economic harm, so outbreaks are carefully monitored. For example, the Florida Fish and Wildlife Conservation Commission provides an up-to-date status report on HABs in Florida. The Texas Parks and Wildlife Department also provides

2943-420: Is a scarcity. The technology to safely and efficiently reuse wastewater , both from domestic and industrial sources, should be a primary concern for policy regarding eutrophication. There are many ways to help fix cultural eutrophication caused by agriculture. Some recommendations issued by the U.S. Department of Agriculture include: The United Nations framework for Sustainable Development Goals recognizes

3052-491: Is accumulating inside freshwater bodies. In marine ecosystems , nitrogen is the primary limiting nutrient; nitrous oxide (created by the combustion of fossil fuels ) and its deposition in the water from the atmosphere has led to an increase in nitrogen levels, and also the heightened levels of eutrophication in the ocean. Cultural or anthropogenic eutrophication is the process that causes eutrophication because of human activity. The problem became more apparent following

3161-445: Is adapted to living in such conditions. The eutrophication of areas outside its natural range partially explain the fish's success in colonizing these areas after being introduced. Some harmful algal blooms resulting from eutrophication, are toxic to plants and animals. Freshwater algal blooms can pose a threat to livestock. When the algae die or are eaten, neuro - and hepatotoxins are released which can kill animals and may pose

3270-442: Is an expensive and often difficult process. Laws regulating the discharge and treatment of sewage have led to dramatic nutrient reductions to surrounding ecosystems. As a major contributor to the nonpoint source nutrient loading of water bodies is untreated domestic sewage, it is necessary to provide treatment facilities to highly urbanized areas, particularly those in developing countries , in which treatment of domestic waste water

3379-778: Is bioremediation involving cultured plants and animals. Nutrient bioextraction or bioharvesting is the practice of farming and harvesting shellfish and seaweed to remove nitrogen and other nutrients from natural water bodies. It has been suggested that nitrogen removal by oyster reefs could generate net benefits for sources facing nitrogen emission restrictions, similar to other nutrient trading scenarios. Specifically, if oysters maintain nitrogen levels in estuaries below thresholds, then oysters effectively stave off an enforcement response, and compliance costs parties responsible for nitrogen emission would otherwise incur. Several studies have shown that oysters and mussels can dramatically impact nitrogen levels in estuaries. Filter feeding activity

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3488-612: Is caused by excessive concentrations of nutrients, most commonly phosphates and nitrates , although this varies with location. Prior to their being phasing out in the 1970's, phosphate-containing detergents contributed to eutrophication. Since then, sewage and agriculture have emerged as the dominant phosphate sources. The main sources of nitrogen pollution are from agricultural runoff containing fertilizers and animal wastes, from sewage, and from atmospheric deposition of nitrogen originating from combustion or animal waste. The limitation of productivity in any aquatic system varies with

3597-845: Is causing algal blooms to form in places previously considered "impossible" or rare for them to exist, such as under the ice sheets in the Arctic , in Antarctica , the Himalayan Mountains , the Rocky Mountains , and in the Sierra Nevada Mountains . In the U.S., every coastal state has had harmful algal blooms over the last decade and new species have emerged in new locations that were not previously known to have caused problems. Inland, major rivers have seen an increase in their size and frequency. In 2015

3706-439: Is commonly applied in the surface of the water body and it sinks to the bottom of the lake reducing phosphate, such sorbents have been applied worldwide to manage eutrophication and algal bloom (for example under the commercial name Phoslock ). In a large-scale study, 114 lakes were monitored for the effectiveness of alum at phosphorus reduction. Across all lakes, alum effectively reduced the phosphorus for 11 years. While there

3815-452: Is considered beneficial to water quality by controlling phytoplankton density and sequestering nutrients, which can be removed from the system through shellfish harvest, buried in the sediments, or lost through denitrification . Foundational work toward the idea of improving marine water quality through shellfish cultivation was conducted by Odd Lindahl et al., using mussels in Sweden. In

3924-399: Is derived from blooms of any of several species of dinoflagellate , such as Karenia brevis . However, the term is misleading since algal blooms can widely vary in color, and growth of algae is unrelated to the tides . Not all red tides are produced by dinoflagellates. The mixotrophic ciliate Mesodinium rubrum produces non-toxic blooms coloured deep red by chloroplasts it obtains from

4033-629: Is direct injection of compressed air, a technique used in the restoration of the Salford Docks area of the Manchester Ship Canal in England. For smaller-scale waters such as aquaculture ponds, pump aeration is standard. Removing phosphorus can remediate eutrophication. Of the several phosphate sorbents, alum ( aluminium sulfate ) is of practical interest. ) Many materials have been investigated. The phosphate sorbent

4142-474: Is not sufficient to tell the difference between toxic and non-toxic populations. In these cases, tools can be employed to measure the toxin level or to determine if the toxin-production genes are present. In a narrow definition, harmful algal blooms are only those blooms that release toxins that affect other species. On the other hand, any algal bloom can cause dead zones due to low oxygen levels , and could therefore be called "harmful" in that sense. The usage of

4251-619: Is often regarded as the main culprit in cases of eutrophication in lakes subjected to "point source" pollution from sewage pipes. The concentration of algae and the trophic state of lakes correspond well to phosphorus levels in water. Studies conducted in the Experimental Lakes Area in Ontario have shown a relationship between the addition of phosphorus and the rate of eutrophication. Later stages of eutrophication lead to blooms of nitrogen-fixing cyanobacteria limited solely by

4360-481: Is sometimes unclear what causes specific HABs as their occurrence in some locations appears to be entirely natural, while in others they appear to be a result of human activities. Furthermore, there are many different species of algae that can form HABs, each with different environmental requirements for optimal growth. The frequency and severity of HABs in some parts of the world have been linked to increased nutrient loading from human activities. In other areas, HABs are

4469-422: Is that the natural process is very slow, occurring on geological time scales. Eutrophication can have the following ecological effects: increased biomass of phytoplankton , changes in macrophyte species composition and biomass , dissolved oxygen depletion, increased incidences of fish kills , loss of desirable fish species. When an ecosystem experiences an increase in nutrients, primary producers reap

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4578-497: Is the rapid growth of microscopic algae, creating an algal bloom . In freshwater ecosystems , the formation of floating algal blooms are commonly nitrogen-fixing cyanobacteria (blue-green algae). This outcome is favored when soluble nitrogen becomes limiting and phosphorus inputs remain significant. Nutrient pollution is a major cause of algal blooms and excess growth of other aquatic plants leading to overcrowding competition for sunlight, space, and oxygen. Increased competition for

4687-523: The Ohio River had a bloom which stretched an "unprecedented" 650 miles (1,050 km) into adjoining states and tested positive for toxins, which created drinking water and recreation problems. A portion of Utah's Jordan River was closed due to toxic algal bloom in 2016. Off the west coast of South Africa , HABs caused by Alexandrium catanella occur every spring. These blooms of organisms cause severe disruptions in fisheries of these waters as

4796-909: The Republic of Korea and the Russian Federation , of which representatives constitute the NOWPAP Intergovernmental Meeting (IGM), the high-level governing body of NOWPAP, functions as the policy guide and decision-maker. The IGM decisions are executed by the NOWPAP nerve centre, which is called the Regional Coordinating Unit (RCU). Located in Toyama, Japan and Busan , Republic of Korea, the RCU coordinates NOWPAP activities, mostly carried out through

4905-509: The US Environmental Protection Agency in 2008 who stated that HABs include "potentially toxic (auxotrophic, heterotrophic) species and high-biomass producers that can cause hypoxia and anoxia and indiscriminate mortalities of marine life after reaching dense concentrations, whether or not toxins are produced". Harmful algal bloom in coastal areas are also often referred to as "red tides". The term "red tide"

5014-407: The open waters of the continental shelf. Phytoplankton productivity in coastal waters depends on both nutrient and light supply, with the latter an important limiting factor in waters near to shore where sediment resuspension often limits light penetration. Nutrients are supplied to coastal waters from land via river and groundwater and also via the atmosphere. There is also an important source from

5123-441: The 1980s. The is the result of human induced factors such as increased nutrient inputs ( nutrient pollution ) and climate change (in particular the warming of water temperatures). The parameters that affect the formation of HABs are ocean warming , marine heatwaves, oxygen loss , eutrophication and water pollution . HABs contain dense concentrations of organisms and appear as discolored water, often reddish-brown in color. It

5232-545: The Chesapeake Bay, where they are a normal occurrence, are also suspected of being a major source of methane . Scientists have found that HABs were a prominent feature of previous mass extinction events , including the End-Permian Extinction . Tests have shown some toxins near blooms can be in the air and thereby be inhaled, which could affect health. Eating fish or shellfish from lakes with

5341-467: The Gulf of Mexico were witnessed in the early 1500s by explorer Cabeza de Vaca , it is unclear what initiates these blooms and how large a role n anthropogenic and natural factors play in their development. The number of reported harmful algal blooms (cyanobacterial) has been increasing throughout the world. It is unclear whether the apparent increase in frequency and severity of HABs in various parts of

5450-751: The NOWPAP clearinghouse, developing and establishing region-wide data and information system, establishing comprehensive databases, promoting regional information exchange. The Marine Environmental Emergency Preparedness and Response Regional Activity Centre (MERRAC)]: developing cooperative measures for marine pollution preparedness and response including marine litter, implementing the NOWPAP Regional Oil and HNS (Hazardous and Noxious Substances) Spill Contingency Plan. The Pollution Monitoring Regional Activity Centre (POMRAC)]: developing cooperative measures related to atmospheric deposition of contaminants and river and direct inputs of contaminants into

5559-541: The NOWPAP marine environment cause eutrophication and harmful algal blooms ( HAB, also known as red tides ). Other threats are from coastal development, marine transport , land reclamation and intensive mariculture and marine litter . NOWPAP is financed mainly by contributions from the member states to the UNEP Trust Fund for NOWPAP. Current member states are the People’s Republic of China , Japan ,

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5668-607: The Regional Activity Centres (RACs), the implementing arms of NOWPAP. The RACs (under the coordination of the RCU) are responsible for: The Special Monitoring & Coastal Environmental Assessment Regional Activity Centre (CEARAC)]: monitoring and assessment of HAB, developing new monitoring tools using remote sensing, and activities related to the management of marine litter. The Data & Information Network Regional Activity Centre (DINRAC)] : serving as

5777-789: The Sahara Desert are thought to play a major role in causing HAB events. Some algal blooms on the Pacific Coast have also been linked to occurrences of large-scale climatic oscillations such as El Niño events. Other factors such as iron-rich dust influx from large desert areas such as the Sahara are thought to play a role in causing HABs. Some algal blooms on the Pacific coast have also been linked to natural occurrences of large-scale climatic oscillations such as El Niño events. HABs are also linked to heavy rainfall. Although HABs in

5886-590: The United States has created a forecasting tool for regions such as the Great Lakes, the Gulf of Maine, and The Gulf of Mexico. Shorter term predictions can help to show the intensity, location, and trajectory of blooms in order to warn more directly affected communities. Longer term tests in specific regions and bodies help to predict larger scale factors like scale of future blooms and factors that could lead to more adverse effects. Nutrient bioextraction

5995-456: The United States, shellfish restoration projects have been conducted on the East, West and Gulf coasts. Studies have demonstrated seaweed's potential to improve nitrogen levels. Seaweed aquaculture offers an opportunity to mitigate, and adapt to climate change. Seaweed, such as kelp, also absorbs phosphorus and nitrogen and is thus helpful to remove excessive nutrients from polluted parts of

6104-482: The added nutrients can cause potential disruption to entire ecosystems and food webs, as well as a loss of habitat, and biodiversity of species. When overproduced macrophytes and algae die in eutrophic water, their decompose further consumes dissolved oxygen. The depleted oxygen levels in turn may lead to fish kills and a range of other effects reducing biodiversity. Nutrients may become concentrated in an anoxic zone, often in deeper waters cut off by stratification of

6213-532: The algae bloom (such as rapid termination of the HAB as cells convert from the pelagic state to the benthic state). Many of the algal species that undergo this dual-stage life cycle are capable of rapid vertical migration. This migration is required for the movement from the benthic area of bodies of water to the pelagic zone. These species require immense amounts of energy as they pass through the various thermoclines , haloclines , and pycnoclines that are associated with

6322-523: The algae it eats.  As a technical term, it is being replaced in favor of more precise terminology, including the generic term "harmful algal bloom" for harmful species, and " algal bloom " for benign species. There are three main types of phytoplankton which can form into harmful algal blooms: cyanobacteria , dinoflagellates , and diatoms . All three are made up of microscopic floating organisms which, like plants, can create their own food from sunlight by means of photosynthesis . That ability makes

6431-547: The amount of soil runoff and nitrogen-based fertilizers reaching a watershed can be reduced. Waste disposal technology constitutes another factor in eutrophication prevention. Because a body of water can have an effect on a range of people reaching far beyond that of the watershed, cooperation between different organizations is necessary to prevent the intrusion of contaminants that can lead to eutrophication. Agencies ranging from state governments to those of water resource management and non-governmental organizations, going as low as

6540-403: The base of the food web upon which nearly all other marine organisms depend. Of the 5000+ species of marine phytoplankton that exist worldwide, about 2% are known to be harmful or toxic. Blooms of harmful algae can have large and varied impacts on marine ecosystems, depending on the species involved, the environment where they are found, and the mechanism by which they exert negative effects. It

6649-481: The benefits first. In aquatic ecosystems, species such as algae experience a population increase (called an algal bloom ). Algal blooms limit the sunlight available to bottom-dwelling organisms and cause wide swings in the amount of dissolved oxygen in the water. Oxygen is required by all aerobically respiring plants and animals and it is replenished in daylight by photosynthesizing plants and algae. Under eutrophic conditions, dissolved oxygen greatly increases during

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6758-649: The bodies of water in which these cells exist. The other types of algae are diatoms and dinoflagellates , found primarily in marine environments, such as ocean coastlines or bays, where they can also form algal blooms. Coastal HABs are a natural phenomenon, although in many instances, particularly when they form close to coastlines or in estuaries, it has been shown that they are exacerbated by human-induced eutrophication and / or climate change. They can occur when warmer water, salinity, and nutrients reach certain levels, which then stimulates their growth. Most HAB algae are dinoflagellates. They are visible in water at

6867-414: The case of ciguatera , where it is typically a predator fish that accumulates the toxin and then poisons humans. Eutrophication and harmful algal blooms can have economic impacts due to increasing water treatment costs, commercial fishing and shellfish losses, recreational fishing losses (reductions in harvestable fish and shellfish ), and reduced tourism income (decreases in perceived aesthetic value of

6976-431: The catchments. A third key nutrient, dissolved silicon , is derived primarily from sediment weathering to rivers and from offshore and is therefore much less affected by human activity. These increasing nitrogen and phosphorus nutrient inputs exert eutrophication pressures on coastal zones. These pressures vary geographically depending on the catchment activities and associated nutrient load. The geographical setting of

7085-504: The causes of algal blooms are: Nutrients enter freshwater or marine environments as surface runoff from agricultural pollution and urban runoff from fertilized lawns, golf courses and other landscaped properties; and from sewage treatment plants that lack nutrient control systems. Additional nutrients are introduced from atmospheric pollution. Coastal areas worldwide, especially wetlands and estuaries, coral reefs and swamps, are prone to being overloaded with those nutrients. Most of

7194-415: The city of Toledo, Ohio advised its 500,000 residents to not drink tap water as the high toxin level from an algal bloom in western Lake Erie had affected their water treatment plant's ability to treat the water to a safe level. The emergency required using bottled water for all normal uses except showering, which seriously affected public services and commercial businesses. The bloom returned in 2015 and

7303-782: The coastal zone is another important factor as it controls dilution of the nutrient load and oxygen exchange with the atmosphere. The effects of these eutrophication pressures can be seen in several different ways: Surveys showed that 54% of lakes in Asia are eutrophic; in Europe , 53%; in North America , 48%; in South America , 41%; and in Africa , 28%. In South Africa, a study by the CSIR using remote sensing has shown more than 60% of

7412-560: The damaging effects of eutrophication for marine environments. It has established a timeline for creating an Index of Coastal Eutrophication and Floating Plastic Debris Density (ICEP) within Sustainable Development Goal 14 (life below water). SDG 14 specifically has a target to: "by 2025, prevent and significantly reduce marine pollution of all kinds, in particular from land-based activities, including marine debris and nutrient pollution". Policy and regulations are

7521-526: The day, but is greatly reduced after dark by the respiring algae and by microorganisms that feed on the increasing mass of dead algae. When dissolved oxygen levels decline to hypoxic levels, fish and other marine animals suffocate. As a result, creatures such as fish, shrimp, and especially immobile bottom dwellers die off. In extreme cases, anaerobic conditions ensue, promoting growth of bacteria. Zones where this occurs are known as dead zones . Eutrophication may cause competitive release by making abundant

7630-637: The environment and economies. They have been increasing in size and frequency worldwide, a fact that many experts attribute to global climate change . The U.S. National Oceanic and Atmospheric Administration (NOAA) predicts more harmful blooms in the Pacific Ocean . Potential remedies include chemical treatment, additional reservoirs, sensors and monitoring devices, reducing nutrient runoff, research and management as well as monitoring and reporting. Terrestrial runoff, containing fertilizer, sewage and livestock wastes, transports abundant nutrients to

7739-400: The environment. Such nutrient pollution usually causes algal blooms and bacterial growth, resulting in the depletion of dissolved oxygen in water and causing substantial environmental degradation . Approaches for prevention and reversal of eutrophication include minimizing point source pollution from sewage and agriculture as well as other nonpoint pollution sources. Additionally,

7848-450: The great lakes, but are also prone to bodies of salt water as well. Many of the species that form harmful algae blooms will undergo a dual-stage life system. These species will alternate between a benthic resting stage and a pelagic vegetative state. The benthic resting stage corresponds to when these species are resting near the ocean floor. In this stage, the species cells are waiting for optimal conditions so that they can move towards

7957-584: The interface between freshwater and saltwater, can be both phosphorus and nitrogen limited and commonly exhibit symptoms of eutrophication. Eutrophication in estuaries often results in bottom water hypoxia or anoxia, leading to fish kills and habitat degradation. Upwelling in coastal systems also promotes increased productivity by conveying deep, nutrient-rich waters to the surface, where the nutrients can be assimilated by algae . Examples of anthropogenic sources of nitrogen-rich pollution to coastal waters include sea cage fish farming and discharges of ammonia from

8066-798: The introduction of bacteria and algae-inhibiting organisms such as shellfish and seaweed can also help reduce nitrogen pollution, which in turn controls the growth of cyanobacteria , the main source of harmful algae blooms . The term "eutrophication" comes from the Greek eutrophos , meaning "well-nourished". Water bodies with very low nutrient levels are termed oligotrophic and those with moderate nutrient levels are termed mesotrophic . Advanced eutrophication may also be referred to as dystrophic and hypertrophic conditions. Thus, eutrophication has been defined as "degradation of water quality owing to enrichment by nutrients which results in excessive plant (principally algae) growth and decay." Eutrophication

8175-588: The introduction of chemical fertilizers in agriculture (green revolution of the mid-1900s). Phosphorus and nitrogen are the two main nutrients that cause cultural eutrophication as they enrich the water, allowing for some aquatic plants, especially algae to grow rapidly and bloom in high densities. Algal blooms can shade out benthic plants thereby altering the overall plant community. When algae die off, their degradation by bacteria removes oxygen, potentially, generating anoxic conditions. This anoxic environment kills off aerobic organisms (e.g. fish and invertebrates) in

8284-527: The large cities along the Mediterranean Sea , for example, discharge all of their sewage into the sea untreated. The same is true for most coastal developing countries, while in parts of the developing world, as much as 70% of wastewater from large cities may re-enter water systems without being treated. Residual nutrients in treated wastewater can also accumulate in downstream source water areas and fuel eutrophication, which leads progressively to

8393-568: The last decade, and new species have emerged in some locations that were not previously known to cause problems. HAB frequency is also thought to be increasing in freshwater systems. Researchers have reported the growth of HABs in Europe, Africa and Australia. Those have included blooms on some of the African Great Lakes , such as Lake Victoria , the second largest freshwater lake in the world. India has been reporting an increase in

8502-494: The local population, are responsible for preventing eutrophication of water bodies. In the United States, the most well known inter-state effort to prevent eutrophication is the Chesapeake Bay . Reducing nutrient inputs is a crucial precondition for restoration. Still, there are two caveats: Firstly, it can take a long time, mainly because of the storage of nutrients in sediments . Secondly, restoration may need more than

8611-402: The majority of them an essential part of the food web for small fish and other organisms. Harmful algal blooms in freshwater lakes and rivers, or at estuaries , where rivers flow into the ocean, are caused by cyanobacteria, which are commonly referred to as "blue-green algae", but are in fact prokaryotic bacteria, as opposed to algae which are eukaryotes . Some cyanobacteria, including

8720-565: The marine and coastal environment, and the activities on integrated coastal and river basin management (ICARM) . Eutrophication Eutrophication is a general term describing a process in which nutrients accumulate in a body of water, resulting in an increased growth of microorganisms that may deplete the oxygen of water. Eutrophication may occur naturally or as a result of human actions. Manmade, or cultural, eutrophication occurs when sewage , industrial wastewater , fertilizer runoff , and other nutrient sources are released into

8829-426: The most susceptible. In shore lines and shallow lakes, sediments are frequently resuspended by wind and waves which can result in nutrient release from sediments into the overlying water, enhancing eutrophication. The deterioration of water quality caused by cultural eutrophication can therefore negatively impact human uses including potable supply for consumption, industrial uses and recreation. Eutrophication can be

8938-462: The natural productivity of lakes. A few artificial lakes also demonstrate the reverse process ( meiotrophication ), becoming less nutrient rich with time as nutrient poor inputs slowly elute the nutrient richer water mass of the lake. This process may be seen in artificial lakes and reservoirs which tend to be highly eutrophic on first filling but may become more oligotrophic with time. The main difference between natural and anthropogenic eutrophication

9047-513: The nervous system causing serious injury or death. In the summer of 2015, the state governments closed important shellfish fisheries in Washington , Oregon , and California because of high concentrations of domoic acid in shellfish. In the marine environment, single-celled, microscopic, plant-like organisms naturally occur in the well-lit surface layer of any body of water. These organisms, referred to as phytoplankton or microalgae , form

9156-400: The number of blooms each year. In 1977 Hong Kong reported its first coastal HAB. By 1987 they were getting an average of 35 per year. Additionally, there have been reports of harmful algal blooms throughout popular Canadian lakes such as Beaver Lake and Quamichan Lake. These blooms were responsible for the deaths of a few animals and led to swimming advisories. Global warming and pollution

9265-537: The ongoing degradation of dams, lakes, rivers, and reservoirs - source water areas that are starting to become known as ecological infrastructure, placing increasing pressure on wastewater treatment works and water purification plants. Such pressures, in turn, intensify seasonal HABs. Climate change contributes to warmer waters which makes conditions more favorable for algae growth in more regions and farther north. In general, still, warm, shallow water, combined with high-nutrient conditions in lakes or rivers, increases

9374-447: The open ocean, via mixing of relatively nutrient rich deep ocean waters. Nutrient inputs from the ocean are little changed by human activity, although climate change may alter the water flows across the shelf break. By contrast, inputs from land to coastal zones of the nutrients nitrogen and phosphorus have been increased by human activity globally. The extent of increases varies greatly from place to place depending on human activities in

9483-557: The phosphorus concentration. Phosphorus-base eutrophication in fresh water lakes has been addressed in several cases. Eutrophication is a common phenomenon in coastal waters , where nitrogenous sources are the main culprit. In coastal waters, nitrogen is commonly the key limiting nutrient of marine waters (unlike the freshwater systems where phosphorus is often the limiting nutrient). Therefore, nitrogen levels are more important than phosphorus levels for understanding and controlling eutrophication problems in salt water. Estuaries , as

9592-459: The production of coke from coal. In addition to runoff from land, wastes from fish farming and industrial ammonia discharges, atmospheric fixed nitrogen can be an important nutrient source in the open ocean. This could account for around one third of the ocean's external (non-recycled) nitrogen supply, and up to 3% of the annual new marine biological production. Coastal waters embrace a wide range of marine habitats from enclosed estuaries to

9701-504: The rate of supply (from external sources) and removal (flushing out) of nutrients from the body of water. This means that some nutrients are more prevalent in certain areas than others and different ecosystems and environments have different limiting factors. Phosphorus is the limiting factor for plant growth in most freshwater ecosystems, and because phosphate adheres tightly to soil particles and sinks in areas such as wetlands and lakes, due to its prevalence nowadays more and more phosphorus

9810-622: The reservoirs surveyed were eutrophic. The World Resources Institute has identified 375 hypoxic coastal zones in the world, concentrated in coastal areas in Western Europe, the Eastern and Southern coasts of the US, and East Asia , particularly Japan . As a society, there are certain steps we can take to ensure the minimization of eutrophication, thereby reducing its harmful effects on humans and other living organisms in order to sustain

9919-404: The risk of harmful algal blooms. Warming of summer surface temperatures of lakes, which rose by 0.34 °C decade per decade between 1985 and 2009 due to global warming, also will likely increase algal blooming by 20% over the next century. Although the drivers of harmful algal blooms are poorly understood, they do appear to have increased in range expansion and frequency in coastal areas since

10028-425: The sea. Some cultivated seaweeds have very high productivity and could absorb large quantities of N, P, CO 2 , producing large amounts of O 2 having an excellent effect on decreasing eutrophication. It is believed that seaweed cultivation in large scale should be a good solution to the eutrophication problem in coastal waters . Another technique for combatting hypoxia /eutrophication in localized situations

10137-484: The seawater and stimulates bloom events. Natural causes, such as river floods or upwelling of nutrients from the sea floor , often following massive storms, provide nutrients and trigger bloom events as well. Increasing coastal developments and aquaculture also contribute to the occurrence of coastal HABs. Effects of HABs can worsen locally due to wind driven Langmuir circulation and their biological effects . HABs from cyanobacteria (blue-green algae) can appear as

10246-540: The sunlight used by plants and algae to photosynthesise, or by depleting the dissolved oxygen needed by fish and other aquatic animals, which can lead to fish die-offs. When such oxygen-depleted water covers a large area for an extended period of time, it can become hypoxic or even anoxic; these areas are commonly called dead zones . These dead zones can be the result of numerous different factors ranging from natural phenomenon to deliberate human intervention, and are not just limited to large bodies of fresh water as found in

10355-489: The surface. These species will then transition from the benthic resting stage into the pelagic vegetative state - where they are more active and found near the water body surface. In the pelagic vegetative state, these cells are able to grow and multiply. It is within the pelagic vegetative state that a bloom is able to occur - as the cells rapidly reproduce and take over the upper regions of the body of water. The transition between these two life stages can have multiple effects on

10464-403: The term "harmful algal blooms" in the media and scientific literature is varied. In a broader definition, all "organisms and events are considered to be HABs if they negatively impact human health or socioeconomic interests or are detrimental to aquatic systems". A harmful algal bloom is "a societal concept rather than a scientific definition". A similarly broad definition of HABs was adopted by

10573-400: The toxins in the phytoplankton cause filter-feeding shellfish in affected waters to become poisonous for human consumption. As algal blooms grow, they deplete the oxygen in the water and block sunlight from reaching fish and plants. Such blooms can last from a few days to many months. With less light, plants beneath the bloom can die and fish can starve. Furthermore, the dense population of

10682-407: The toxins they produce or from using up oxygen in the water which can lead to fish die-offs. Not all algal blooms produce toxins, however, with some only discoloring water, producing a smelly odor, or adding a bad taste to the water. Unfortunately, it is not possible to tell if a bloom is harmful from just appearances, since sampling and microscopic examination is required. In many cases microscopy

10791-732: The water body). Water treatment costs can be increased due to decreases in water transparency (increased turbidity ). There can also be issues with color and smell during drinking water treatment. Human health effects of eutrophication derive from two main issues excess nitrate in drinking water and exposure to toxic algae. Nitrates in drinking water can cause blue baby syndrome in infants and can react with chemicals used to treat water to create disinfection by-products in drinking water. Getting direct contact with toxic algae through swimming or drinking can cause rashes, stomach or liver illness, and respiratory or neurological problems . One response to added amounts of nutrients in aquatic ecosystems

10900-695: The water body. This also affects terrestrial animals, restricting their access to affected water (e.g. as drinking sources). Selection for algal and aquatic plant species that can thrive in nutrient-rich conditions can cause structural and functional disruption to entire aquatic ecosystems and their food webs, resulting in loss of habitat and species biodiversity. There are several sources of excessive nutrients from human activity including run-off from fertilized fields, lawns, and golf courses, untreated sewage and wastewater and internal combustion of fuels creating nitrogen pollution. Cultural eutrophication can occur in fresh water and salt water bodies, shallow waters being

11009-464: The water column and may only be made available again during autumn turn-over in temperate areas or in conditions of turbulent flow. The dead algae and organic load carried by the water inflows into a lake settle to the bottom and undergo anaerobic digestion releasing greenhouse gases such as methane and CO 2 . Some of the methane gas may be oxidised by anaerobic methane oxidation bacteria such as Methylococcus capsulatus , which in turn may provide

11118-403: The water since many pets have died from algal blooms. In at least one case, people began getting sick before warnings were issued. There is no treatment available for animals, including livestock cattle, if they drink from algal blooms where such toxins are present. Pets are advised to be kept away from algal blooms to avoid contact. In some locations visitors have been warned not to even touch

11227-474: The water. Boaters have been told that toxins in the water can be inhaled from the spray from wind or waves. Ocean beaches, lakes and rivers have been closed due to algal blooms. After a dog died in 2015 from swimming in a bloom in California's Russian River , officials likewise posted warnings for parts of the river. Boiling the water at home before drinking does not remove the toxins. In August 2014

11336-817: The widespread genus Microsystis , can produce hazardous cyanotoxins such as microcystins , which are hepatotoxins that harm the liver of mammals. Other types of cyanobacteria can also produce hepatotoxins, as well as neurotoxins, cytotoxins, and endotoxins. Water purification plants may be unable to remove these toxins, leading to increasingly common localised advisories against drinking tap water, as happened in Toledo, Ohio in August ;2014. In August 2021, there were 47 lakes confirmed to have algal blooms in New York State alone. In September 2021, Spokane County's Environmental Programs issued

11445-480: The world each year. In 1987 a new illness emerged: amnesic shellfish poisoning (ASP). People who had eaten mussels from Prince Edward Island were found to have ASP. The illness was caused by domoic acid , produced by a diatom found in the area where the mussels were cultivated. A 2013 study found that toxic paralytic shellfish poisoning in the Philippines during HABs has caused at least 120 deaths over

11554-481: The world is in fact a real increase or is due to increased observation effort and advances in species identification technology. In 2008, the U.S. government prepared a report on the problem, "Harmful Algal Bloom Management and Response: Assessment and Plan". The report recognized the seriousness of the problem: It is widely believed that the frequency and geographic distribution of HABs have been increasing worldwide. All U.S. coastal states have experienced HABs over

11663-592: Was forecast again for the summer of 2016. In 2004, a bloom in Kisumu Bay, which is the drinking water source for 500,000 people in Kisumu , Kenya , suffered from similar water contamination. In China, water was cut off to residents in 2007 due to an algal bloom in its third largest lake, which forced 2 million people to use bottled water. A smaller water shut-down in China affected 15,000 residents two years later at

11772-580: Was recognized as a water pollution problem in European and North American lakes and reservoirs in the mid-20th century. Breakthrough research carried out at the Experimental Lakes Area (ELA) in Ontario, Canada, in the 1970s provided the evidence that freshwater bodies are phosphorus-limited. ELA uses the whole ecosystem approach and long-term, whole-lake investigations of freshwater focusing on cultural eutrophication. Eutrophication

11881-450: Was variety in longevity (21 years in deep lakes and 5.7 years in shallow lakes), the results express the effectiveness of alum at controlling phosphorus within lakes. Alum treatment is less effective in deep lakes, as well as lakes with substantial external phosphorus loading. Finnish phosphorus removal measures started in the mid-1970s and have targeted rivers and lakes polluted by industrial and municipal discharges. These efforts have had

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