24. Dead zones • Dead zones are large areas in the ocean that have low oxygen concentration. • The marine life in these areas mostly suffocates and dies or if they are mobile like the fish then, they leave the area. • Though at many times, dead zones occur naturally, scientists are also of the opinion that they are created due to increased human activity. • The main cause of the zones created by humans is nutrient pollution. Excess nutrients (nitrogen and phosphorus) can result in the overgrowth of algae, which later decomposes in the water consuming excess oxygen, depleting the supply available for the marine life. Dead zones can be found in virtually every oceanic body, the largest encompassing almost the whole bottom of the Baltic Sea. Another large dead zone is located in the Gulf of Mexico. Other dead zones occur off the western coasts of North and South America and off the coast of Namibia and western coast of India. Global warming triggered by climate change is predicted to lead to an expansion of these dead zones. However, it is not certain whether the climate change would lead to the removal of the last traces of oxygen from the bay as well.
  • Earth Rotation and Revolution
  • spherical coordinate system
  • Distribution of Temperature
  • Continental Drift Theory
  • Differences and Similarities Between Plate Tectonics and Continental Drift
  • Mountains & their Formation
  • Types of mountains
  • Formation of Plateaus
  • Plains
  • lakes
  • Types Of Rocks
  • How Rocks Change
  • Drainage Pattern
  • Weathering-Introduction & its types
  • Agents Of Erosion
  • Factors affecting rate of Weathering
  • Structure Of Atmosphere
  • Composition of Atmosphere
  • Insolation & Heat Budget
  • Clean Development Mechanism (CDM)
  • Coral bleaching
  • Red Panda