Ocean Systems

Human Dependence on Ocean Systems Humans depend on ocean systems for the following: 

1. Food - oceans provide fish and shellfish to large populations
2.  Water - oceans indirectly provide terrestrial (land) life with fresh water through the water cycle
3. Transportation-oceans provide an efficient way to transport goods on ships
4. Climate Regulation - ocean currents circulate warmer water from the equator to arctic regions and cooler water from arctic regions to the equator; currents help to moderate temperature extremes
5. Recreation - boating, fishing, diving, and surfing

Negative Human Impact on Ocean Systems Humans negatively impact ocean systems in the following ways: 

1. Overfishing-populations of fish and shellfish are dropping quickly because they are being removed from oceans faster than they are able to reproduce
2. Runoff and Pollution-toxic chemicals from factories runoff into rivers and end up in the ocean; these toxic chemicals can kill fish or make them potentially dangerous for human consumption; fertilizers and pesticides wash off into rivers and are carried into the ocean
3. Habitat Destruction-many wetlands and other habitats have been destroyed by human developments and pollution

Positive Human Impact on Ocean Systems Humans positively impact ocean systems in the following way:

1. Artificial Reefs - humans create artificial reefs by sinking old ships, train cars, and other non-toxic structures; these artificial reefs help to support large fish populations and new food webs; artificial reefs support lite much like naturally occurring coral reefs 

Watershed 

• An area of land where all of the water that is under it or drains off of it goes into the same place 
• Human activities can have a significant impact on Earth's water systems 
• Surface Water - water on the surface of Earth such as a river, stream, lake or ocean 
• Ground Water - water present beneath the Earth's surface
• Runoff has increased due to more roads, houses, and buildings being constructed
• Improper disposal of trash can eventually make its way into the ocean or other water systems
• Fertilizers eventually make their way into ground or surface water
• Excess fertilizers or other forms of pollution can spread to other areas as they travel along the watershed

Ground Water 

• Found within on aquifer 
• Aquifer-a layer of rock or soil that can hold water 

• An aquifer consists of permeable material - water is able to move through the material 
• Impermeable -a layer of material that does not allow water to move through (ex. Bedrock)

• Water held within an aquifer is known as a saturated zone 
• The top of a saturated zone is known as a water table - the water table will change as the level of water in an aquifer changes 

Primary vs Secondary Succession

• Primary succession occurs following an opening of pristine habitat, examples:
  • Oil spills
  • Glaciers melting and retreating
  • Volcanic eruptions

primary succession usually takes a long time, hundreds of years

• Secondary succession is a response to a disturbance, whereby newer communities are created after the event. examples: 
  • After forest fires 
  • tsunamis

secondary succession usually takes a short time, following some natural disaster