Chapter 9 Flashcards
(28 cards)
List oceanic ecosystem in order from bottom to top
- Primary producers (oxygen producing, 203 absorbing, phytoplankton, seaweed)
- Herbivorous consumers (zooplankton, cockles)
- 1st level carnivorous consumers (juvenile fish, jellyfish, crustaceans)
- 2nd level carnivorous consumers (larger fish)
- 3rd level carnivorous consumers (squid)
- Top carnivores (shark, dolphin, albatross)
What is thermohaline circulation?
Carbon saturated water moving around the globe like a carbon-salt conveyer belt. Result of different water densities
How does thermohaline work?
High salinity water cools and sinks in North Atlantic
Deep water returns to surface in Indian and pacific oceans through upwelling
(Sheds energy/carbon, moves nutrients, salt, heat)
Where are the most important fishing grounds?
On and along continental shelves less than 200 nautical miles of shore
How much of worlds protein supply do fish supply?
20%
What is happening to the fish?
Declining numbers
Smaller than those caught in the past
What is a shifting baseline?
Using current or recent degraded state as baseline rather than historical data
What is prey switching?
predator shifts target species after theirs gets depleted or not available
Continues to move down the food line
What is serial depletion?
One stock after another becomes depleted as result of prey switching
Point source vs non point source
Point source –> can point to a source of pollution (pulp mill, factory)
Non point source –> total of multiple sources (agriculture)
Why is the ocean so polluted?
If receives all of the water flowing off land as well airborne contaminants
What are the two forms of chemical pollutants?
Toxic
Nutrients
What is endocrine disruption?
Interference of normal bodily proccesses (sex, metabolism, growth) by chemicals in soaps, detergents, that are released into ecosystem. Can cause feminization in some aquatic species.
What effect does nutrient enrichment have on the ocean?
Can cause oxygen depletion leads to large dead areas
Threatening certain species by creating higher number of male fish to female
What is an oxygen deficient area called?
Dead areas are called hypoxic.
How much would surface temperature have to increase to cause global destruction of coral reef ecosytems?
1 degree c
What is the most sensitive indicator of global climate change?
The arctic Ocean
How does heat cause sea levels to rise?
When water warms molecules are moving faster causing water to take up more space. (Thermal expansion effect)
Melting of ice sheets and glaciers
How many zettajoules of energy has the earth absorbed between 1865 and 1997
150 Zettajoules –> equivalent to 2.4 billion atomic bombs (heat, not radiation energy)
Why are BC shellfish struggling to survive?
Oceans becoming more acidic
What year did the United Nations Convention on the Law (UNCLOS) form?
1994
Ratified by Canada in 2003
What was the most important provision enacted by UNCLOS
Exclusive economic zones (EEZs): Special rights regarding exploration and use of marine resources (water and wind energy)
Stretches 200 nautical miles
establishes 45% of seabed as common property
What is the fastest way to create change in fishing methods?
End subsidies that support commercial fisheries
What is a marine protected area?
underwater reserve set aside and protected from human exploitation because of fragility, rarity or valued biodiversity of ecosystem
