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Home >> In Dead Water - Climate Change, Pollution, Over-harvest, and Invasive Species in the World's Fishing Grounds

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In Dead Water - Climate Change, Pollution, Over-harvest, and Invasive Species in the WorldIn Dead Water - Climate Change, Pollution, Over-harvest, and Invasive Species in the World's Fishing Grounds
UNEP rapid response assessment on the state of the world's seas. In this report, the locations of the most productive fishing grounds in the World – from shallow, coastal waters to the deep and high seas- are compared to projected scenarios of climate change, ocean acidification, coral bleaching, intensity of fisheries, land-based pollution, increase of invasive species infestations and growth in coastal development.
Available online at: http://www.grida.no/publications/rr/in-dead-water
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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Deep waters within and beyond areas of national jurisdiction in East Africa Deep waters within and beyond areas of national jurisdiction in East Africa
The figure demonstrates that the overwhelming majority of marine areas under national jurisdiction in East Africa are deeper than 200 metres (dark blue). Areas in red indicate where the geology/geomorphology might justify (subject to further research and interpretation) a submission/claim to be made by coastal states individually or jointly to increase their national seabed and subsoil areas, which, in turn, may be of major economic potential.
01 Feb 2008 - by UNEP-WCMC and UNEP/GRID-Arendal
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Estimated contributions to sea-level rise (1993-2003) Estimated contributions to sea-level rise (1993-2003)
The two main reasons for sea-level rise are thermal expansion of ocean waters as they warm, and increase in the ocean mass, principally from land-based sources of ice (glaciers and ice caps, and the ice sheets of Greenland and Antarctica). Global warming from increasing greenhouse gas concentrations is a significant driver of both contributions to sea-level rise. From 1955 to 1995, ocean thermal expansion is estimated to have contributed about 0....
01 Oct 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Cumulative impacts on the marine environment Cumulative impacts on the marine environment
Climate change may, through effects on ocean currents, elevated sea temperatures, coral bleaching, shifts in marine life, ocean acidification and much more severely exacerbate the combined actions of accelerating coastal development, coastal pollution and dead zones, invasive species, bottom trawling and over-harvest. These impacts will be the strongest in 10-15% of the Worlds oceans. These areas, however, are concurrent with the most productive ...
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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Human impact in the coastal zones Human impact in the coastal zones
Infrastructure development, intensive agricultural expansion, urbanisation and coastal development are increasing the flow of sediments and sewage into the ocean. The situation is most severe around Europe, the East coast of the United States, East of China and in Southeast Asia. These are also primary fishing grounds. Coastal zones are identified as approximately 75 km from the coastline, and this map identifies the most common impact class in t...
01 Nov 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Plankton distribution changes, due to climate changes - North Sea Plankton distribution changes, due to climate changes - North Sea
With melting sea ice and warming of the oceans, marine species change their distributions, affecting entire food chains and ocean productivity. In 2005 the subtropical dinoflagellate Ceratium hexacanthum was found in CPR samples from the North Sea at levels that were 6 standard deviations above previous measurements since 1958. Further evidence of this warning signal is seen in the appearance of a Pacific planktonic plant (a diatom Neodenticula s...
01 Feb 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Coastal regions with observations of dense shelf water flushing Coastal regions with observations of dense shelf water flushing
Knowledge and mapping of these processes is still scarce due to uneven research effort. The map shows sites with known dense shelf water cascading phenomena, which often may involve the 'flushing' effect. It is most likely that this phenomenon is also active off the coast of Alaska, Chile, Argentina and West and southern Africa and in parts of the Indian Ocean. Dense shelf water cascading is highly sensitive to increases in temperature, and hence...
01 Feb 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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World fisheries hotspots, 2004 World fisheries hotspots, 2004
The World’s most productive fishing grounds are confined to major hotspots, less than 10% of the World oceans. The maps shows annual catch (tonnes per km2) for the World’s oceans. Notice the strong geographic concurrence of continental shelves, upwelling and primary productivity and the amount of fish caught by fisheries.
01 Feb 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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depth depth
About depth
29 Nov 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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scenario scenario
About scenario
29 Nov 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Distribution of coldwater and tropical coral reefs Distribution of coldwater and tropical coral reefs
Coral reefs are marine ridges or mounds, which have formed over millennia as a result of the deposition of calcium carbonate by living organisms, predominantly corals, but also a rich diversity of other organisms such as coralline algae and shellfish. The coldwater reefs are highly susceptible to deep-sea trawling and ocean acidification from climate change, which has its greatest impacts at high latitudes, while tropical reefs will become severe...
01 Feb 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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canyondsw canyondsw
About canyondsw
29 Nov 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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stocks stocks
About stocks
29 Nov 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Trends in natural disasters Trends in natural disasters
With growing population and infrastructures the world’s exposure to natural hazards is inevitably increasing. This is particularly true as the strongest population growth is located in coastal areas (with greater exposure to floods, cyclones and tidal waves). To make matters worse any land remaining available for urban growth is generally risk-prone, for instance flood plains or steep slopes subject to landslides. The statistics in this graphic r...
29 Nov 2007 - by Emmanuelle Bournay, UNEP/GRID-Arendal
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Climate change and tropical coral reefs, scenarios for bleaching events Climate change and tropical coral reefs, scenarios for bleaching events
Projected areas of above normal sea temperature where coral bleaching is likely to occur for the SRES A2 scenario (continuing current trends) by two different models, the PCM (1.7°C increase in 100 years) and the HadCM3 (3°C increase in 100 years) by approximately 2035 (left) and by 2055 (right). Both models project severe annual bleaching in more than 80% of the Worlds coral reefs by 2080.
01 Feb 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Acidification due to climate change - impacts for oceans and coral reefs Acidification due to climate change - impacts for oceans and coral reefs
As carbon concentrations in the atmosphere increase from land use changes and emissions from fossil fuels - so do concentrations in the ocean, with resultant acidification as a natural chemical process. The skeletons of coldwater coral reefs may dissolve, perhaps already within a few decades. The impacts will be greatest at high latitudes. This will have an impact on all marine organisms with calcerous shells and body parts, in addition to coral ...
01 Feb 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Atmospheric concentrations of carbon dioxide (CO2) - Mauna Loa or Keeling curve Atmospheric concentrations of carbon dioxide (CO2) - Mauna Loa or Keeling curve
Atmospheric concentration of CO2 is steadily rising, and oceans directly assimilate CO2. As ocean concentration of CO2 increases, the oceans automatically become more acidic. This, in turn, may have severe impacts on coral reefs and other biocalcifying organisms. There is little debate on the effect as this is a straight-forward chemical process, but the implications for marine life, that may be severe due to many very pH-sensitive relationships...
01 Nov 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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shelfwater shelfwater
About shelfwater
29 Nov 2007 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Major pathways and origins of invasive species infestations in the marine environment Major pathways and origins of invasive species infestations in the marine environment
All across the planet, the number and severity of outbreaks and infestations of invasive species (i.e. species purposefully or accidentally introduced in non-native environments) is growing, and invasions of marine habitats are now occurring at an alarming rate. Exotic and invasive species have been identified by scientists and policymakers as a major threat to marine ecosystems, with dramatic effects on biodiversity, biological productivity, hab...
01 Feb 2008 - by Hugo Ahlenius, UNEP/GRID-Arendal
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