100 likes | 256 Views
The Oceans. Vanessa Borgia Ecology . Geography. 360 million km, Continuous interconnected mass of water 3 major basins Pacific- 180 million km 2 , deepest~ 4000 m Atlantic- 106 million km 2 , pole to pole Indian- under 75 million km 2 , Southern Hemisphere Undersea mountain stud the floor.
E N D
The Oceans Vanessa Borgia Ecology
Geography • 360 million km, Continuous interconnected mass of water • 3 major basins • Pacific- 180 million km2, deepest~ 4000 m • Atlantic- 106 million km2, pole to pole • Indian- under 75 million km2, Southern Hemisphere • Undersea mountain stud the floor
Structure • Littoral/ intertidal- shallow shorelines under rise and fall of the tides • Neritic zone- from coast to the margin of the continental shelf. • Oceanic zone- beyond continental shelf. • 3 vertical depth zones • Mesopelagic- 200- 1000m • Bathypelagic- 1000-4000m • Abyssal- 4000-6000m • Hadal Zone- deepest part of ocean • Benthic- habitats on bottom of ocean • Pelagic- off the bottom regardless of depth
Physical Conditions • Light • 80% solar energy absorbed in first 10m. Ultraviolet/infrared first few meters. Below 50-60 m it is a blue twilight. • Temperature • Sunlight increased kinetic state or velocity of motion of water molecules, keeps temp up. Thermocline- layer of cold water on bottom and warm on top. Thermal Stratification- layering of water by temp. • Water Movements • Winds drive currents-transport nutrients and O2. Currents moderate climate, fertilize the surface H20 and stimulate photosynthesis. Gynes- currents sweep over oceans to create circulation system. Upwelling- deep H20 moved to the surface.
Chemical Conditions • Salinity • Varies with latitude among sea. 34g of salt per kg of water= about 36.5%. Baltic Sea- surrounded by temp and boral forest biomes receives large inputs of freshwater, local salinities of 7% or lower. Red Sea- deserts over 40% salinities. • Oxygen • Increase near ocean surface and decrease with depth.
Biology • Phytoplankton- microscopic organisms that drift with the currents. • Zooplankton- small animals that drift w/ current. • Deep sea organisms are nourished by organic matter fixed by photosynthesis near the surface. • Ocean shines with blue of pure water and is called a “biological desert.”
Human Influences • Decline of large whale population gave a warning of what we can do to open an ocean system. • Overfishing led to major decline in commercially important fish stocks. • Another threat possibility of dumping nuclear and chemical wastes.