 Sediment from the Mississippi River carries fertilizer to the Gulf of Mexico Dead zones are hypoxic (low-oxygen) areas in the world's oceans, the observed incidences of which have been increasing since oceanographers began noting them in the 1970s. The term could as well apply to the identical phenomenon in large lakes. In March 2004, when the recently-established UN Environment Programme published its first Global Environment Outlook Year Book (GEO Year Book 2003) it reported 146 dead zones in the world oceans where marine life could not be supported due to depleted oxygen levels. Some of these were as small as a square kilometer, but the largest dead zone covered 70,000 square kilometers. From http://daac. ...
From http://daac. ...
It has been suggested that Anoxic sea water, Oxygen minimum zone, and Hypoxic zone be merged into this article or section. ...
General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ...
The 1970s decade refers to the years from 1970 to 1979, also called The Seventies. ...
2004 : January - February - March - April - May - June - July - August - September - October - November - December Deaths • 08 Abu Abbas • 20 Queen Juliana • 28 Peter Ustinov • 30 Alistair Cooke More March 2004 deaths Ongoing events EU Enlargement Exploration of Mars: Rovers Haiti Rebellion Israeli-Palestinian conflict Occupation of Iraq Same-sex marriage in...
Klaus Töpfer, UNEP Exec. ...
Klaus Töpfer, UNEP Exec. ...
Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ...
Causes of dead zones
Marine dead zones can be caused by the process of eutrophication. Other natural oceanographic phenomena can cause deoxygenation of parts of the water column. For example, enclosed bodies of water such as fjords or the Black Sea have shallow sills at their entrances causing water to be stagnant there for a long time. The eastern tropical Pacific Ocean and Northern Indian Ocean have lowered oxygen concentrations which are thought to be in regions where there is minimal circulation to replace the oxygen that is consumed (e.g. Pickard & Emery 1982, p 47). See also http://www.nodc.noaa.gov/OC5/WOA01F/oxsearch.html Eutrophication, strictly speaking, means an increase in chemical nutrients -- typically compounds containing nitrogen or phosphorus -- in an ecosystem. ...
Lysefjorden in Norway A fjord (pronounced FEE-ord or fyord, SAMPA: [fi:3:d] or [faI3:d]; sometimes written fiord) is a glacially overdeepened valley, usually narrow and steep-sided, extending below sea level and filled with salt water. ...
For other uses, see Black Sea (disambiguation). ...
Remains of organisms found within sediment layers near the mouth of the Mississippi River indicate four hypoxic events before the advent of artificial fertilizer. In these sediment layers, anoxia-tolerant species are the most prevalent remains found. The periods indicated by the sediment record correspond to historic records of high river flow recorded by instruments at Vicksburg, Mississippi. This article or section cites very few or no references or sources. ...
For the river in Canada, see Mississippi River (Ontario). ...
Asphyxia is a condition of severely deficient supply of oxygen to the body. ...
Vicksburg is a city in Warren County, Mississippi. ...
This article is about the U.S. state. ...
Effects of dead zones
 Underwater video frame of the sea floor in the Western Baltic covered with dead or dying crabs, fish and clams killed by oxygen depletion Low oxygen levels recorded along the Gulf Coast of North America have led to reproductive problems in fish involving decreased size of reproductive organs, low egg counts and lack of spawning. fishkill Baltic - image Uwe Kils GFDL File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...
The Baltic Sea is located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. ...
The Gulf of Mexico is a major body of water bordered and nearly landlocked by North America. ...
North America North America is a continent[1] in the Earths northern hemisphere and (chiefly) western hemisphere. ...
In a study of the Gulf killifish by the Southeastern Louisiana University done in three bays along the Gulf Coast, fish living in bays where the oxygen levels in the water dropped to 1 to 2 parts per million (ppm) for 3 or more hours per day were found to have smaller reproductive organs. The male gonads were 34 to 50% as large as males of similar size in bays where the oxygen levels were normal (6 to 8 ppm). Females were found to have ovaries that were half as large as those in normal oxygen levels. The number of eggs in females living in hypoxic waters were only one-seventh the number of eggs in fish living in normal oxygen levels. (Landry, et al., 2004) A bluefin notho killifish, Nothobranchius rachovii, from East Africa. ...
Southeastern Louisiana University is a state-funded public university that is located in the city of Hammond, Louisiana. ...
A sex organ, or primary sexual characteristic, as narrowly defined, is any of those anatomical parts of the body which are involved in sexual reproduction and constitute the reproductive system in a complex organism; in mammals, these are: Female: Bartholins glands, cervix, clitoris, Fallopian tubes, labia, ovaries, Skenes...
Another study by the University of Texas at Austin Marine Science Institute was done on the Atlantic croaker fish in Pensacola Bay, Florida. The study was of year-old croakers that live in an estuary that has summer-long hypoxic conditions. During the study, none of the fish spawned at the expected time, or later. Examination of sample fish determined that they lacked mature eggs or sperm. (Murphy, et al., 2004) University of Texas redirects here. ...
Genera See text. ...
Nickname: Location in Escambia County and the state of Florida Coordinates: , Country State County Escambia Government - Mayor John Fogg Area - City 39. ...
This article is about the U.S. State of Florida. ...
For other meanings, see Estuary (disambiguation) RÃo de la Plata estuary An estuary is a semi-enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea. ...
Fish raised in laboratory created hypoxic conditions showed extremely low sex-hormone concentrations and increased elevation of activity in two genes triggered by the hypoxia-inductile factor (HIF) protein. Under hypoxic conditions, HIF pairs with another protein, ARNT. The two then bind to DNA in cells, activating genes in those cells. For other uses, see Hormone (disambiguation). ...
For other uses, see Gene (disambiguation). ...
A representation of the 3D structure of myoglobin, showing coloured alpha helices. ...
Under normal oxygen conditions, ARNT combines with estrogen to activate genes. Hypoxic cells in a test tube didn't react to estrogen placed in the tube. HIF appears to render ARNT unavailable to interact with estrogen, providing a mechanism by which hypoxic conditions alter reproduction in fish. (Johanning, et. al, 2004)
It might be expected that fish would flee this potential suffocation, but they are often quickly rendered unconscious and doomed. Slow moving bottom-dwelling creatures like clams, lobsters and oysters are unable to escape. All colonial animals are extinguished. The normal mineralization and recycling that occurs among benthic life-forms is stifled. Seagrass growing off the coast of the Florida Keys. ...
Another cause is the oil spills that wipe out the plankton which is a major food suply for fish
Locations of dead zones In the 1970s, marine dead zones were first noted in areas where intensive economic use stimulated "first-world" scientific scrutiny: in the U.S. East Coast's Chesapeake Bay, in Scandinavia's strait called the Kattegat, which is the mouth of the Baltic Sea and in other important Baltic Sea fishing grounds, in the Black Sea, (which may have been anoxic in its deepest levels for millennia, however) and in the northern Adriatic. The Chesapeake Bay - Landsat photo The Chesapeake Bay where the Susquehanna River empties into it. ...
Over-Simplified diagram A strait is a narrow channel of water that connects two larger bodies of water, and thus lies between two land masses. ...
The Baltic Sea The Kattegat (Danish), or Kattegatt (Swedish), is a bay of the North Sea and a continuation of the Skagerrak, bounded by Denmark and Sweden. ...
The Baltic Sea is located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. ...
For other uses, see Black Sea (disambiguation). ...
The Adriatic Sea is an arm of the Mediterranean Sea separating the Apennine peninsula (Italy) from the Balkan peninsula, and the system of the Apennine Mountains from that of the Dinaric Alps and adjacent ranges. ...
Other marine dead zones have apparently appeared in coastal waters of South America, China, Japan, southeast Australia, and even in the waters of New Zealand, which have a reputation for being some of the planet's most pristine near-coastal marine environments. Nevertheless, in the case of New Zealand, with a population of only 4 million people, set in a region of low to moderate nitrate nitrogen supply at 100 m (http://www.nodc.noaa.gov/OC5/WOA01F/nusearch.html) previous reports of dead zones arise because of misinterpretations of two papers (Taylor et al. 1985; Morrisey et al. 2000) and the most recent UNEP report omits New Zealand from the affected regions (http://www.gpa.unep.org/bin/php/igr/igr2/supporting.php).
Oregon Off the coast of Cape Perpetua, Oregon, there is also a dead zone with a 2006 reported size of 300 square miles.[1] This dead zone is unique in that it only exists during the summer, perhaps due to seasonal wind patterns. Oregon coast at Brookings, Oregon. ...
Gulf of Mexico Currently the most notorious dead zone is a 22,126 square kilometer region in the Gulf of Mexico, where the Mississippi River dumps high-nutrient runoff from its vast drainage basin, which includes the heart of U.S. agribusiness, the Midwest, affecting important shrimp fishing grounds. A dead zone off the coast of Texas near Freeport was discovered in July 2007.[2] Gulf of Mexico in 3D perspective. ...
For the river in Canada, see Mississippi River (Ontario). ...
In agriculture, agribusiness is a generic term that refers to the various businesses involved in the food production chain, including farming, seed, agrichemicals, farm machinery, wholesaling, processing, distribution, and retail sales. ...
Reversal of dead zones Dead zones are not irreversible. The Black Sea dead zone, previously the largest dead zone in the world, largely disappeared between 1991 and 2001 after fertilizers became too costly to use following the collapse of the Soviet Union and the demise of centrally planned economies in Eastern and Central Europe. Fishing has again become a major economic activity in the region.[3] For other uses, see Black Sea (disambiguation). ...
Pre-1989 division between the West (grey) and Eastern Bloc (orange) superimposed on current national boundaries: Russia (dark orange), other countries of the former USSR (medium orange),members of the Warsaw pact (light orange), and other former Communist regimes not aligned with Moscow (lightest orange). ...
Central Europe The Alpine Countries and the Visegrád Group (Political map, 2004) Central Europe is the region lying between the variously and vaguely defined areas of Eastern and Western Europe. ...
While the Black Sea "cleanup" was largely unintentional and involved a drop in hard-to-control fertilizer usage, the U.N. has advocated other cleanups by reducing large industrial emissions.[3] From 1985-2000, the North Sea dead zone had nitrogen reduced by 37% when policy efforts by countries on the Rhine River reduced sewage and industrial emissions of nitrogen into the water. The North Sea is a sea of the Atlantic Ocean, located between the coasts of Norway and Denmark in the east, the coast of the British Isles in the west, and the German, Dutch, Belgian and French coasts in the south. ...
For other uses, see Rhine (disambiguation). ...
The chemical Aluminium sulfate can be used to reduce phosphates in water. Aluminium sulfate is a widely used industrial chemical. ...
Notes - ^ http://news.wired.com/dynamic/stories/D/DEAD_ZONE?SITE=WIRE&SECTION=HOME&TEMPLATE=DEFAULT
- ^ http://www.bloomberg.com/apps/news?pid=20601109&sid=a4Tb2AFv6CRk&refer=home
- ^ a b Mee, Laurence. "Reviving Dead Zones", Scientific American, November 2006. Retrieved on December 9, 2006.
References - Osterman, L.E., et al. 2004. Reconstructing an 180-yr record of natural and anthropogenic induced hypoxia from the sediments of the Louisiana Continental Shelf. Geological Society of America meeting. Nov. 7-10. Denver. http://gsa.confex.com/gsa/2004AM/finalprogram/abstract_75830.htm Abstract.
- Pickard, G.L. and Emery, W.J. 1982. Description Physical Oceanography: An Introduction. Pergamon Press, Oxford, 249 pp.
- Landry, C.A., S. Manning, and A.O. Cheek. 2004. Hypoxia suppresses reproduction in Gulf killifish, Fundulus grandis. e.hormone 2004 conference. Oct. 27-30. New Orleans.
- Murphy, C. . . . P. Thomas, et al. 2004. Modeling the effects of multiple anthropogenic and environmental stressors on Atlantic croaker populations using nested simulation models and laboratory data. Fourth SETAC World Congress, 25th Annual Meeting in North America. Nov. 14-18. Portland, Ore. Abstract.
- Johanning, K., et al. 2004. Assessment of molecular interaction between low oxygen and estrogen in fish cell culture. Fourth SETAC World Congress, 25th Annual Meeting in North America. Nov. 14-18. Portland, Ore. Abstract.
- Taylor, F.J., N.J. Taylor, J.R. Walsby 1985. A bloom of planktonic diatom Ceratulina pelagica off the coastal northeastern New Zealand in 1983, and its contribution to an associated mortality of fish and benthic fauna. Intertional Revue ges. Hydrobiol. 70: 773-795.
- Morrisey, D.J. 2000. Predicting impacts and recovery of marine farm sites in Stewart Island New Zealand, from the Findlay-Watling model. Aquaculture 185: 257-271.
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