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Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
Marine dead zones
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Marine dead zones

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  • The dead zone usually forms in the spring and summer when water and air temperatures begin to rise. At this time the discharge of the Mississippi River also increases. Freshwater from the river overlies saltier, denser water in the Gulf, forming a stratified layer. The layering is intensified by warming from the sun. The freshwater brings nutrients, which are primarily from agricultural runoff. The additional nutrients stimulate high production or blooms of microscopic algae (phytoplankton). When phytoplankton die, they sink to the bottom. Some phytoplankton are consumed by zooplankton. Dead zooplankton and their fecal pellets also sink to the bottom where organic matter accumulates. This organic matter is decomposed by bacteria in the lower reaches of the water column and on the bottom. The decomposition process uses up oxygen there. These low oxygen levels persist throughout the spring and summer until a cold front or tropical storm stirs up the water column and replenishes oxygen.
  • The environment is effected by polluted water from fertilizers carried by the rain.
  • Benthos is the food base for many fishes.Under hypoxic conditions: Bottom dwellers become stressed and will die if oxygen levels remain low for long periods.Shrimp, crabs, snails and starfish emerge from the protection of the sediment and their burrows seeking O2 and become easy prey or eventually die. — Immobile bottom dwellers cannot escape. — Diversity is decreased.These changes and decreases in diversity indicate a degrading environment.
  • Transcript

    • 1. 1
    • 2. 2
    • 3. Outline  What is Marine Dead Zone (MDZ) ?  History of Ocean Dead Zones  Dead zones around the world  How this happens?  What causes hypoxia?  When does the hypoxia occur?  Environmental, Social & Economic effects  What can be done?  HABHRCA  QUIZ TIME  Conclusion  Acknowledgement  ReferencesMarine Dead Zones W.A.D.M.Wijethilake 3 AS2009167
    • 4. What is Marine Dead Zone (MDZ) ?  NOAA  Hypoxia = Reduced level of oxygen in the water  Less oxygen dissolved in the water  Occur naturally OR created or enhanced by human activity.Marine Dead Zones W.A.D.M.Wijethilake 4 AS2009167
    • 5. What is Marine Dead Zone (MDZ)? cnt.  Many physical, chemical, and biological factors combine to create dead zones  Nutrient pollution is the primary cause – Human encroachment  East Coast, the Gulf of Mexico (U.S) & Great lakes  Second largest - Northern Gulf of Mexico  A significant portion of the worlds population - nearly half of which lives within 40 miles of a coast is vulnerable to harmfully over-enriched ecosystems,"Marine Dead Zones W.A.D.M.Wijethilake 5 AS2009167
    • 6.  The technical term for low oxygen = hypoxia.  When oxygen concentration falls below 2mg/l = hypoxic area  The term for no oxygen is = anoxia.  Anoxia = 0 mg/l dissolved oxygenMarine Dead Zones W.A.D.M.Wijethiake 6 AS2009167
    • 7. Outline What is Marine Dead Zone (MDZ) ? History of Ocean Dead Zones Dead zones around the world How this happens? What causes hypoxia? When does the hypoxia occur? Environmental, Social & Economic effects What can be done? HABHRCA QUIZ TIME Conclusion Acknowledgement References Marine Dead Zones W.A.D.M.Wijethilake 7 AS2009167
    • 8.  Dead zones in the coastal oceans have spread exponentially since the 1960s and have serious consequences for ecosystem functioning.  First recorded in the 1970s off the coasts of developed countries.  Dead zones were originally discovered in the,  US,  Chesapeake Bay  Kattegat Strait in Scandinavia  Mouth of the Baltic Sea  Black Sea,  Northern Adriatic Sea.  Currently about 400 ocean DZs worldwide,  Ranging in size from 1 square km to 20,000 square Km.Marine Dead Zones W.A.D.M.Wijethilake 8 AS2009167
    • 9.  Dead zones are reversible.  The Black Sea dead zone, previously the largest in the world, largely disappeared between 1991 and 2001  After fertilizers became too costly  Fishing had again became a major economic activity in the regionMarine Dead Zones W.A.D.M.Wijethilake 9 AS2009167
    • 10. From 1985 to 2000, theNitrogen in North Sea DZ had reduced by 37% BECAUSE,,,  Policy efforts by countries on the Rhine River , they reduced  Sewage and  Industrial emissions of Nitrogen into the water.  Other cleanups have taken place in the US along the  Hudson River and  San Francisco BayMarine Dead Zones W.A.D.M.Wijethilake 10 AS2009167
    • 11. Hood Canal  Fjord forming the western lobe & one of the four main basins in the state of Washington  NATURAL WATER WAYMarine Dead Zones W.A.D.M.Wijethilake 11 AS2009167
    • 12. Outline What is Marine Dead Zone (MDZ) ? History of Ocean Dead Zones Dead zones around the world How this happens? What causes hypoxia? When does the hypoxia occur? Environmental, Social & Economic effects What can be done? HABHRCA QUIZ TIME Conclusion Acknowledgement References Marine Dead Zones W.A.D.M.Wijethilake 12 AS2009167
    • 13.  In 2008, 415 Dead Zones Were Identified  NASA Releases New Map of Aquatic Dead Zones July 23, 2010Marine Dead Zones W.A.D.M.Wijethilake 13 AS2009167
    • 14.  Red circles on this map show the location and size of many of our planet’s dead zones.  Black dots show where dead zones have been observed, but their size is unknown.  It’s no coincidence that dead zones occur downriver of places where human population density is high (darkest brown)  Naturally occurring low-oxygen zones are regular features in some parts of the ocean. (Coastal upwelling areas)  However, these zones may grow larger with the additional nutrient inputs from agricultural runoff.Marine Dead Zones W.A.D.M.Wijethilake 14 AS2009167
    • 15. Two famous hypoxic regions are:  The Gulf of Mexico, fed by the overly-enriched Mississippi River  2. The Black Sea, which is currently recovering - Soviet areaMarine Dead Zones W.A.D.M.Wijethilake 15 AS2009167
    • 16. Outline What is Marine Dead Zone (MDZ) ? History of Ocean Dead Zones Dead zones around the world How this happens? What causes hypoxia? When does the hypoxia occur? Environmental, Social & Economic effects What can be done? HABHRCA QUIZ TIME Conclusion Acknowledgement References Marine Dead Zones W.A.D.M.Wijethilake 16 AS2009167
    • 17. Step 1  Eutrophication starts with farmers spreading fertilizers rich in Nitrates and Phosphates on their fields.  When it rains much of the fertilizers are washed into large bodies of waterMarine Dead Zones W.A.D.M.Wijethilake 17 AS2009167
    • 18. Step 2  The added nutrients then cause an increase in plant and algae growthMarine Dead Zones W.A.D.M.Wijethilake 18 AS2009167
    • 19. Step 3: The algae begins to grows in such large quantities thatsunlight is blocked from the lower levels of ocean.Less light means that species of plants and animals areonly able to live at certain depths in the water due to lackof sunlight.Marine Dead Zones W.A.D.M.Wijethilake 19 AS2009167
    • 20. Step 4  Like all other organisms the algae eventually start to die and the fall to the bottom of the ocean.  There bacteria attempt to breakdown the decomposing matter  But in the process they consume large amounts of oxygen and leave the water uninhabitable for many species such as fish.Marine Dead Zones W.A.D.M.Wijethilake 20 AS2009167
    • 21. Marine Dead Zones W.A.D.M.Wijethilake 21 AS2009167
    • 22. Outline What is Marine Dead Zone (MDZ) ? History of Ocean Dead Zones Dead zones around the world How this happens? What causes hypoxia? When does the hypoxia occur? Environmental, Social & Economic effects What can be done? HABHRCA QUIZ TIME Conclusion Acknowledgement References Marine Dead Zones W.A.D.M.Wijethilake 22 AS2009167
    • 23. Marine Dead Zones W.A.D.M.Wijethilake 23 AS2009167
    • 24. Natural factors Human induced Slow water circulation & mixing Altering the river flows, landscapes Changes in weather Altering the marine life High growth of Algae Adding excess nutrients to the waters that can fuel extra Algae growth Loading of Carbon & Nitrogen Adding extra carbon to the ecosystem Changes in the native marine life Influencing climate change compositionMarine Dead Zones W.A.D.M.Wijethilake 24 AS2009167
    • 25. Marine Dead Zones W.A.D.M.Wijethiake 25 AS2009167
    • 26. Sometimes Eutrophication is human – induced  The culprits are:  Agricultural fertilizer  Domesticated animal manure  Industrial & urban runoff  Sewage  Atmospheric nitrogen  These waste products have caused nitrogen and phosphorus in to coastal areas in the last fifty years ago.  In Europe and the U.S. fertilizer and manure are the main sources, because much of their sewage is treated before entering the waterMarine Dead Zones W.A.D.M.Wijethilake system. AS2009167 26
    • 27. Marine Dead Zones W.A.D.M.Wijethilake 27 AS2009167
    • 28.  There are several causes of ocean pollution including oil pollution, marine debris, toxic materials, and ocean dumping and mining.  Oil pollution is not only caused by large devastating tanker spills, it is also caused through runoff from land and industrial wastes & natural seepage which find their way to the ocean through drains.  Other causes include intensive farming, septic tank, pesticide, animal dung, household waste,waste water, nuclear waste... etcMarine Dead Zones W.A.D.M.Wijethiake 28 AS2009167
    • 29. Outline What is Marine Dead Zone (MDZ) ? History of Ocean Dead Zones Dead zones around the world How this happens? What causes hypoxia? When does the hypoxia occur? Environmental, Social & Economic effects What can be done? HABHRCA QUIZ TIME Conclusion Acknowledgement References Marine Dead Zones W.A.D.M.Wijethilake 29 AS2009167
    • 30.  Hypoxic conditions were disrupted in the fall by tropical storms or cold fronts  Associated with increased wind and wave action, which increases mixing in the entire water column.  This mixing replenishes oxygen concentration from the surface to the bottom of the water column.  The dead zone usually forms in the spring and summer  When water and air temperatures begin to rise.Marine Dead Zones W.A.D.M.Wijethilake 30 AS2009167
    • 31. Outline What is Marine Dead Zone (MDZ) ? History of Ocean Dead Zones Dead zones around the world How this happens? What causes hypoxia? When does the hypoxia occur? Environmental, Social & Economic effects What can be done? HABHRCA QUIZ TIME Conclusion Acknowledgement References Marine Dead Zones W.A.D.M.Wijethilake 31 AS2009167
    • 32. Environmental Social Economic This eventually sparks Humans are exposed to The fish industry takes the eutrophication toxins through the greatest his in terms process. contaminated fish or of economic effects water. caused by eutrophication. Marine life dies or suffers serious health Eutrophication is greatly Dwindling (decline) problems. caused by contaminated fish populations will local water from force fishing companies. Algal blooms create factories, farms, sewage, toxins, such as mercury homes, etc., entering the or PCBs (Polychlorinated ecosystem and disturbing Biphenyls), that get its cycles. absorbed by the sea life.Marine Dead Zones W.A.D.M.Wijethilake 32 AS2009167
    • 33.  As well as marine animals, the problem greatly affects human communities, which rely on the coast and its resources for their livelihoods.  For example, a massive algae bloom in 1998 coast Hong Kong $40 million USD as it wiped out almost the entirety of Hong Kongs fish farms.Marine Dead Zones W.A.D.M.Wijethilake 33 AS2009167
    • 34.  Dead zones can also effect……  Benthos, 1. Stressed or die 2. Decreased diversity 3. Degraded environmentMarine Dead Zones W.A.D.M.Wijethilake 34 AS2009167
    • 35. Outline What is Marine Dead Zone (MDZ) ? History of Ocean Dead Zones Dead zones around the world How this happens? What causes hypoxia? When does the hypoxia occur? Environmental, Social & Economic effects What can be done? HABHRCA QUIZ TIME Conclusion Acknowledgement References Marine Dead Zones W.A.D.M.Wijethilake 35 AS2009167
    • 36.  Programs and initiatives are being implemented by the UN Environment Program and the US Environmental Protection Agency.  The National Resources Defense Council created a bill called OCEANS 21(the Oceans, Conservation, Education, and National Strategy for the 21st Century Act).  In Georiga, GreenLaw works to challenge industry and government actions that have compromised the environment.Marine Dead Zones W.A.D.M.Wijethilake 36 AS2009167
    • 37.  - The Black Sea was once the largest dead zone in the world, but during 1991-2001, fertilizers stopped entering the ecosystem resulting in a reversal. The sea naturally restored its equilibrium.  - Solutions for preventing eutrophication is removing algae growth by means of filtration. This would be effective but costly.  Stop the use of fertilizers !  - There other means of fertilizing crops, e.g. compostMarine Dead Zones W.A.D.M.Wijethilake 37 AS2009167
    • 38.  What Can be Done to Remediate the Problem? Solutions include:  Using fewer fertilizers and adjusting the timing of fertilizer applications  Control of animal wastes  Monitoring of septic systems and sewage treatment facilities to reduce discharge of nutrients to surface water and groundwater  Careful industrial practices such as limiting the discharge of nutrients, organic matter, and chemicals from manufacturing facilities.  Funding efforts to restore wetlands along the coast to naturally filter the water before it enters the ocean.Marine Dead Zones W.A.D.M.Wijethilake 38 AS2009167
    • 39.  These solutions are relatively simple to implement and would significantly reduce the input of nitrogen and phosphorus.  A similar approach has been used successfully in the Great Lakes recovery from eutrophication.Marine Dead Zones W.A.D.M.Wijethilake 39 AS2009167
    • 40. Outline What is Marine Dead Zone (MDZ) ? History of Ocean Dead Zones Dead zones around the world How this happens? What causes hypoxia? When does the hypoxia occur? Environmental, Social & Economic effects What can be done? HABHRCA QUIZ TIME Conclusion Acknowledgement References Marine Dead Zones W.A.D.M.Wijethilake 40 AS2009167
    • 41. Harmful Algal Bloom and Hypoxia Research and Control ActMarine Dead Zones W.A.D.M.Wijethilake 41 AS2009167
    • 42.  In December 2004,  US Congress recognized the severity of these threats  Reauthorized the Harmful Algal Bloom and Hypoxia Research and Control Act of 1998 (HABHRCA 1998) with the Harmful Algal Bloom and Hypoxia Amendments Act of 2004Marine Dead Zones W.A.D.M.Wijethilake 42 AS2009167
    • 43.  Scientific understanding and ability to detect, monitor, assess, and predict HAB and hypoxia events.  It authorized funding for existing and new competitive research programs on HABs and hypoxia, including a new program to research methods of prevention, control, and mitigation of HABs.Marine Dead Zones W.A.D.M.Wijethilake 43 AS2009167
    • 44.  Harmful Algal Bloom Management and Response Assessment and Plan, 2008  Scientific Assessment of Marine Harmful Algal Blooms, 2008  Scientific Assessment of Hypoxia in U.S. Coastal Waters, 2010Marine Dead Zones W.A.D.M.Wijethilake 44 AS2009167
    • 45. Outline What is Marine Dead Zone (MDZ) ? History of Ocean Dead Zones Dead zones around the world How this happens? What causes hypoxia? When does the hypoxia occur? Environmental, Social & Economic effects What can be done? HABHRCA QUIZ TIME Conclusion Acknowledgement References Marine Dead Zones W.A.D.M.Wijethilake 45 AS2009167
    • 46. Conclusion  Marine dead zone is low oxygen area called hypoxic region  Ocean dead zones were occurred till 1960’s  There are about 400 MDZ’s in the world  This is continuous process  Hypoxia can form by both natural & human induced factors  In fall hypoxic regions can disrupt & create in the spring & summer.  There are impacts for Environmental, Social & Economic areas.  There are such plans for avoid MDZ’sMarine Dead Zones W.A.D.M.Wijethilake 46 AS2009167
    • 47.  My heartiest thanks goes to Dr.RRMKP Ranatunga for his vital encouragement.  Persons in Zoology & main library in University of Sri Jayawardenepura.  Mrs.Sunethra Kariyawasam in NARA.  For all are who helped meMarine Dead Zones W.A.D.M.Wijethilake 47 AS2009167
    • 48.  Web sites  Goddard Earth Sciences, Data and Information Services Center, NASA  Bleachpedia  NOAAMarine Dead Zones W.A.D.M.Wijethilake 48 AS2009167

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