9/22: Unit 2 Blog

Our ocean is impacted by the “Big Four”: human, environmental, economic impacts, and governmental legislation. The growth of human population as well as development in technology directly impacts on our oceans today.

Human Impact:

For humans, the ocean equates dumping ground. Sewage, industrial run-off, and chemicals are dumped into the ocean, in addition to oil spills from tanker accidents.  The pollution results in bioaccumulation, in which the toxic chemical levels in organisms increase at each trophic level. Pollution from land affects the ocean too; the excess nutrients from fertilizers used in intensive farming are released into coasts by streams and rivers, a type of pollution called eutrophication. Human activities have also caused a rise in carbon dioxide level, and because the ocean absorbs one-third of the carbon dioxide emissions, it is becoming more acidic, as more carbon dioxide results in decrease in pH.

Environmental Impact:

The human impact ties into environmental impact, like a chain-reaction that further influences the ocean. The negative impact of eutrophication is displayed when blooms result from too much phytoplankton. Then, when the large number of the plankton dies, the sharp increase in decomposition leads to depleted oxygen levels. Eventually, other organisms such as fish die from the lack of oxygen. The environment is complicated, for even an introduction of species can threat the entire ecosystem; visiting ships occasionally introduce new organisms to a habitat. Also, even the slightest change in pH level is a huge issue for the marine ecosystem, as its biodiversity may decrease.

Economic Impact:

Economic impact on the ocean is clearly is seen in fisheries, as advances in fishing equipment and increasing population along the coast are causing full or even overexploiting of fish. As the fish stocks are decreasing, the economic demand calls for unsustainable fishing practices such as dredging and trawling, which damage marine life.

Governmental Legislation

In New Zealand, the government sets limits of commercial fish that can be caught, a quota system, in attempt to manage fish stocks. In the United States, federal agencies have been protecting the marine environment. In 1973, the Endangered Species Act (ESA) was enacted to prevent animal extinction; the legislation lists threatened or endangered species, designates their critical habitats, and restores the populations. The Coral Reef Conservation Act (CRCA) was established in 2000 in order to preserve coral reef ecosystems, establishing several major programs such as the Coral Reef Conservation Fund. Several countries have experienced recent policy changes, which have resulted in the view by some that our ocean cannot be an everlasting dumpster. This hopefully calls for a dramatic change in our usage of the ocean!


Works Cited

"Human Impacts on Marine Environments." Science Learning Hub RSS. The University of 
          Waikato, 8 Oct. 2009. Web. 22 Sept. 2014. 
          <http://www.sciencelearn.org.nz/Contexts/Life-in-the-Sea/Science-Ideas-and-
          Concepts/Human-impacts-on-marine-environments>.
"Laws Protecting the Oceans." Oceana. Oceana, n.d. Web. 22 Sept. 2014. 
          <http://oceana.org/en/policy/laws-protecting-the-oceans>.

9/18: Practice Question #1

a) Shutting down thermohaline circulation would lower the temperature of Western Europe because the salt water in the oceanic region may not be dense in salinity. Thermohaline circulation drives the mixing of surface water and deep water; the supposedly dense, cold, salty water from the poles would sink, allowing warm water from the equator to rise, but if the water from Greenland is not dense enough, then the warm water's rising to Western Europe may not be guaranteed, resulting in a decreased temperature in Western Europe.

b) There would be large populations of fish along the west coasts of most continents because of the upwelling caused by the diverging currents. Upwelling is the rise of ocean water toward its surface, and because deep waters bring nutrients from the bottom, the ecosystem is more productive, allowing large populations of fish to reside.

c) Shutting down thermohaline circulation would affect the transport of nutrients among the oceans of the world because the mixing of surface water and deep water would be prevented, and as a result, the nutrients from the bottom of the ocean would not be transferred to the surface. The diverging currents, then, would not be able to circulate water containing nutrients, which would have been present if the thermohaline circulation were active.

9/16: Unit 2 Checkpoint

Difference between weather and climate?
Weather refers to atmospheric conditions of a region at a certain point of time, whereas climate refers to the average condition of a region over a longer period of time.

Effect of Earth's rotation on atmospheric circulation and ocean currents?
Coriolis Effect. Gyres: Water generally circulates clockwise in Northern hemisphere and counter-clockwise in Southern hemisphere.

Similarities of atmospheric and oceanic circulation patterns? Differences?
Both affected by and influence temperature.
Atmospheric: Air, trade winds/westerlies (consistent temperature - trade winds: warm; westerlies: cold).
Oceanic: Water, thermohalic circulation (more cyclical than trade winds/westerlies).

9/12: Hadley Cell

1. What causes water vapor in the rising air to condense and precipitate?

Answer: Adiabatic cooling.

2. What makes the air rise farther up into the atmosphere after the condensation of water vapor?

Answer: Latent heat release is produced, and air expands.

3. How does the cool air flow back toward the equator after sinking?

Answer: The air reaches Earth's surface as warm, dry air after adiabatic heating.