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Mean surface productivity and eutrophic and hypoxic hot spots in the Mediterranean Mean surface productivity and eutrophic and hypoxic hot spots in the Mediterranean
Eutrophic areas are high primary productivity zones due to excessive nutrients and therefore subject to algal blooms resulting in poor water quality. This can also lead to hypoxic conditions. Hypoxia is the condition where oxygen dissolved in water becomes reduced in concentration to a point where is becomes detrimental to aquatic organisms living in the system.
19 Nov 2013 - by GRID-Arendal
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Dissolved Inorganic Nitrogen export by rivers for world regions Dissolved Inorganic Nitrogen export by rivers for world regions
The figure shows the amounts of nitrogen exported by rivers per year and provides a forecast for the future.
16 Oct 2013 - by GRID-Arendal
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Nitrogen sources to watershed exports to the oceans Nitrogen sources to watershed exports to the oceans
Over the last 20 years, significant data and experience in understanding and addressing the sectoral drivers, pressures, sources, impacts and response to reactive nitrogen have been gathered and progress made in trying to address these issues. The key sectors that are involved include the agriculture, waste-water management, and fertilizer production sectors. As shown in the figure for the year 2000, models indicate that globally, roughly equal a...
16 Oct 2013 - by GRID-Arendal
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Unbalancing the cycle Unbalancing the cycle
The figure compares the flow of nitrogen between the the years 1890 and 1990.
16 Oct 2013 - by GRID-Arendal
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Dead zones and fertilizers Dead zones and fertilizers
The production and use of reactive nitrogen based artificial fertilizers has had huge global benefits providing food for billions through the green revolution. The down side of the increased availability of cheap manufactured nitrogen fertilizer products has been global environment problems associated with excess nutrients, specifically the problems of eutrophication, coastal hypoxic zones and nitrate contaminated groundwater. Tracing the format...
16 Oct 2013 - by GRID-Arendal
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Production of nitrogen Production of nitrogen
The rapid increase in the production of reactive nitrogen via the Haber-Bosch process correlates closely with the increase in world population from about 2.6 billion in 1950 to over 6 billion in 2000 (figure page 78). Based on the figures from Dawson and Hilton (2011), over 2 billion tonnes of reactive nitrogen was manufactured in that period. The enormous increase in artificial fertilizer production catalyzed by the Haber-Bosch process has a...
16 Oct 2013 - by GRID-Arendal
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BSR ecosystem area where acidification and eutrophication exceeds critical loads BSR ecosystem area where acidification and eutrophication exceeds critical loads
Graphics from the year 2000 Baltic 21 biannual indicator-based status report on sustainable development in the Baltic Sea Region (Baltic 21 Series No 1/2000). This graphic shows BSR ecosystem area where acidification and eutrophication exceeds critical loads.
10 Mar 2006 - by Philippe Rekacewicz, UNEP/GRID-Arendal
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Population density in the Baltic Sea drainage basin Population density in the Baltic Sea drainage basin
The density of people per square kilometers have been calculated from various statistical sources, and displays the situation at approximately 1990. Population, and specifically cities, act as driving forces in regards to eutrophication on the Baltic Sea, primarily through nutrients (nitrogen, phosphorous) released through sewage plants.
04 Oct 2005 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Arable land in the Baltic Sea region Arable land in the Baltic Sea region
Ratio of arable land out of total land use in the Baltic Sea drainage basin. Agriculture is one of the main contributors to the nutrient (in this case, primarily nitrogen) influx into the Baltic Sea, and thus a main driver for the eutrophication problems in the sea. The displays the situation at approximately 1990.
04 Oct 2005 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Pasture Land - Baltic Sea drainage basin Pasture Land - Baltic Sea drainage basin
Ratio of pasture land total land use in the Baltic Sea drainage basin. Agriculture is one of the main contributors to the nutrient (in this case, primarily nitrogen) influx into the Baltic Sea, and thus a main driver for the eutrophication problems in the sea. The displays the situation at approximately 1990.
04 Oct 2005 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Harmful algal blooms in the West Central Atlantic, 1970-96 Harmful algal blooms in the West Central Atlantic, 1970-96
The graphic shows the trend of the number of harmful algal blooms in the Western Atlantic from 1970 to 1996. The excess growth of algae is often caused by pollution, and can have negative or fatal effects on some species of fish.
28 Sep 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
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Sites with dead zones (oxygen depletion on the sea bottom) Sites with dead zones (oxygen depletion on the sea bottom)
Dead zones (hypoxic i.e. oxygen deficient water) in the coastal zones are increasing, typically surrounding major industrial and agricultural centers. This is commonly occuring due to nutrient pollution, in the form of nitrogen and phosphorous leading to algal blooms and eutrophication
01 Feb 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Ratio of wastewater treatment Ratio of wastewater treatment
Sewage treatment is low or absent in many parts of the World, leading to eutrophication of the coastal zone, (toxic) algae blooms and dramatically reduce the ability of coral to recover from bleaching events dramatically. The data reflects the bodies of the UNEP Regional Seas programme.
01 Nov 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Alkalinity in major rivers Alkalinity in major rivers
This graphic shows the average bicarbonate concentrations, in milligrams per litre, at major river mouths for the time periods 1976 to 1990 and 1991 to 2000. The graphic also shows the changes in average bicarbonate levels between these two time periods. Bicarbonate is an indication of the alkalinity in the rivers which reflects the geology (rock, minerals, sand) and increases the buffering capacity, but can also increase the risk of eutrophicati...
17 May 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
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Nitrate in major rivers Nitrate in major rivers
Considering the data for all the rivers at the continental level, there has been little change in nitrate (NO3-N) concentrations between the two decades under comparison. Changes in the median value were not statistically significant. European rivers showed the highest nitrate loads transported to the marine environment. Comparing data from the two decades, North American and European rivers have remained fairly stable, while major river basins i...
17 May 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
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Land cover - Baltic Sea region (BALANS) Land cover - Baltic Sea region (BALANS)
The Baltic Sea region is covered by primarily forested land and cropland. This land cover map, delineated for the Baltic Sea drainage basin, is using the dataset prepared through the BALANS project, and represents the situation around year 2000.
04 Oct 2005 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Wetlands in the Baltic Sea drainage basin Wetlands in the Baltic Sea drainage basin
Percentage of wetlands out of total land area (by grid cell) for the Baltic Sea drainage basin. Wetlands acts as buffers in cases such as antropogenic nutrient releases (which leads to eutrophication) and acidification. The ratios have been estimated from various sources, and resembles the situation at approximately 1990.
04 Oct 2005 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Discharge of selected pollutants Discharge of selected pollutants
Nitrogen and phosphorous represents nutrients that can be seen as pollutants, as large concentations of those increase eutrophication. Nutrients are present in primarily commercial fertilisers and in sewage. A measure of eutrophication is biochemical oxygen demand (BOD), which measures the activity in the water column. High BOD means that there is low water quality (in terms of eutrophication) and high activity of bacteria in the water. This grap...
29 Nov 2007 - by Philippe Rekacewicz, UNEP/GRID-Arendal
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Nitrate levels: concentrations at river mouths Nitrate levels: concentrations at river mouths
Nutrients are essential to life. In aquatic systems, nitrogen and phosphorus are the two nutrients that most commonly control the growth of aquatic plants, algae and bacteria. Nitrogen and phosphorus are considered to be the primary drivers of eutrophication of aquatic ecosystems, where increased nutrient concentrations lead to increased primary productivity. Some systems are naturally eutrophic, whereas others have become eutrophic as a result o...
26 Jan 2009 - by Philippe Rekacewicz
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Industrial areas and seasonal zones of oxygen depleted waters Industrial areas and seasonal zones of oxygen depleted waters
This graphic illustrates the strong link between areas with high densities of industrial activity and zones of seasonally oxygen-depleted waters. There is a strong link between areas with high densities of industrial activity and zones of seasonal oxygen-depleted waters. In recent years there has been an increasing focus on treating and reducing municipal and industrial waste, and on reducing nitrogen levels in agricultural runoff. However, less...
26 Jan 2009 - by Phillipe Rekacewicz, (Le Monde diplomatique) February 2008
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