Ocean Systems: Human Dependence and Modification

Human Dependenceand Modification

2 Major Systems:

•Ocean currents

•Ocean food webs

Turn and Talk to Your Neighbor

1. How do Ocean Currents effect humans?

2. How do we depend on Ocean Food Webs?

Human DependenceWe depend on the ocean for:

1. Weather• The oceans absorb a lot of

energy from the sun. • The warmer the water the

more evaporation happens. The more evaporation that happens, the more rain there will be.

• The cooler the water the less evaporation happens. The less evaporation the less rain falls.

Human DependenceWe depend on the ocean for:2. Food

• Seafood provides a lot of world’s protein. (Fish, Shrimp, Oysters, Crabs) (1/6 of the worlds population depends on the ocean as their primary source of protein.)

3. Transportation• most of the worlds goods are transported by

ship across oceans.

4. Recreation• Many countries main source of income is

through ocean tourism: (Beach resorts, sport fishing, scuba diving, boating.)

1. Over-fishing

•Disrupts the food web

which may cause organisms to migrate to other areas

Human Modification

Suppose all the TUNA were removed from the food web below: How would this effect the other organisms

in the food web? How would it effect humans?

Human Modification

2. Artificial Reefs• human-made underwater structure, typically

built for the purpose of promoting/preserving

marine lifeTexas Clipper – (9 min)

Human Modification

3. Run Off and Pollution

Excess amounts ofPhosphorus/Nitrogen enter rivers and streams in runoff from farming and factory waste. Phosphorus and nitrogen happen to be the main food source of many types of algae.

Harmful Algal Blooms“Red Tides”

Red Tides Video Clip

HABs (Harmful algal blooms a.k.a. Red Tides) possibly result from this excess phosphorus/nitrogen being dumped into the ocean. Some HABs occur seasonally and naturally, while others appear to be linked to runoff/pollution.

Turn and Talk

What can we do to help prevent HABs from happening?

Is it possible to completely stop them from happening? Why or why not?