Vanessa Borgia Ecology 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 Oxygen 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.