THE BIPOLAR SEESAW
The bi-polar seesaw is an oscillating meridional (what does meridional mean???) overturning regime driven by two
deepwater sources - the North Atlantic Deep Water (NADW) in the north, and Antarctic Bottom Water (AABW) in the
south. By analyzing ice core samples, scientists were able to determine that as deepwater formation revs up in the
North Atlantic, it slows down in Antarctica and vice versa. The thermohaline circulation flip-flops may be responsible for
the 1500 year cycles in ice-rafted debris in the northern North Atlantic, leading to the notion that the bipolar seesaw has
an oscillation with a frequency of about 1500 years. Because of deep water variability, there will be a periodic decrease
in the transformation between surface waters and deep waters in the North Atlantic (basically not enough turnover).
This leads to a decrease in the northward flow of warm tropical surface water (basically a slowing down of the conveyor
belt). Thus, more heat remains in the Southern ocean, warming it up, and less heat is transferred to the North Atlantic,
making it cooler.
BETA EFFECT
The beta effect is the term used to describe the situation where the Coriolis effect increases linearly with latitude. In
other words, it changes at a constant rate (NOT constant itself). This leads to the natural tendency of eddies to move
Westward in the Northern Hemisphere (change in Coriolis with latitude). The beta effect is particularly strong in the
Northern Hemisphere and in the Gulf Stream.
Western Intensification from Beta effect
Coriolis
constant
Coriolis
changing
with
latitude
Here is a good picture to describe how a surface current can be deep versus shallow and has different “slopes”:
THE CROMWELL CURRENT
The Cromwell Current (also called Pacific Equatorial Undercurrent or just Equatorial Undercurrent) is an eastwardflowing subsurface current that extends the length of the equator in the Pacific Ocean. It is 250 miles (400 km) wide and
flows to the east. It is hidden 300 feet (100 m) under the surface of the Pacific Ocean at the Equator it is relatively
narrow in depth compared to other ocean currents being only 100 feet deep. It has 1000 times the volume of Mississippi
River and its length is 3500 miles (6000 km).
EL NINO & RESULTING ISSUES
The El Nino phenomenon (mainly in the Pacific) is NOT normally associated with
W.) increased hurricane activity in the Caribbean (in the Atlantic)
X.) heavy rain and flooding in California (next to Pacific)
Y.) drought in Indonesia (in the Pacific)
Z.) colder winters in the northern US (coming from the Pacific)
W is the correct answer
WIDEST CONTINENTIAL SHELF
The widest continental shelf in the world extends 1,210 km (750 miles) off the coast of Siberia, Russia, into the Arctic
Ocean. However, the question was about the Atlantic coast of South America. I think it may have been an “out of the
following” situation. Just remember that Pacific coast of South America and Indian coast of Africa are extremely narrow.
FRESHWATER INTO AN ESTUARY
Freshwater flows into an estuary, leaving more water, so the ebb tide is going to be longer since the freshwater will be
leaving. Typically, estuaries have an asymmetrical tidal range. Look:
SILICEOUS OOZE AND PLACEMENT
Silica shells dissolve rapidly in warm water, so a cold-water environment such as at high latitudes (especially at divergent
currents where there is upwelling of cold waters) is perfect for siliceous ooze. Thus, it is the type of sediment most
commonly found at high latitude beneath divergent currents. Read below to distinguish types of oozes and their main
locations:
SPEED OF “RELATIVE” PLATE MOTION
The key to this question was the “relative” part. The 'absolute plate motion' (the motion of a plate with respect to the
Earth's deep interior) than the 'relative plate motion' (the relative movement that takes place along an individual plate
boundary). Here are two charts, showing the various speeds, both actual (absolute) and relative:
DIFFERENCE BETWEEN ORGANIC AND INORGANIC COMPOUNDS
Organic compounds are extracted from living organism (plants, animals, etc.) and inorganic compounds are extracted
from non-living things (rocks, in laboratory, etc.). These days organic compounds can be artificially created by human
beings, and moreover organic compounds have been found in outer space where there are no living beings. But the
difference which is very basic, in terms of chemistry there are lot of differences between Organic and inorganic
compounds, lets discuss them in detail.
Organic Compounds:Substance whose molecules contain one or more (often many more) carbon atoms covalently bonded with another
element or radical (including hydrogen, nitrogen, oxygen, the halogens as well as phosphorus, silicon and sulfur).
A few exceptions are carbon monoxide, carbon dioxide, carbonates, cyanides, cyanates, carbides, and thyocyanates,
which are considered inorganic. Examples of organic compounds are carbohydrates, lipids, proteins and nucleic acids.
Inorganic Compounds:
Any compound NOT containing carbon atoms. Any compound that contains carbon atoms ionically bound to other
atoms (carbon monoxide, carbon dioxide, carbonates, cyanides, cyanates, carbides, and thyocyanates) is included in this
group. Inorganic compounds have salt forming capacity while organic compounds do not form salts. Organic
compounds have the molecules which contain carbon and hydrogen. Inorganic compound come mainly from mineral
sources of non-biological origin. Examples:- NaCl,H2,H2SO4 etc.
Difference Between Organic and Inorganic Compounds (Organic vs Inorganic Compounds):1. Organic compounds are extracted from living beings while inorganic compounds are created either due to natural
processes or in the laboratory.
2. Inorganic compounds can make salt(as they are ionic), while organic does not due to their covalency.
3. Organic compounds contain carbon, while inorganic compound contain metal and other element.
4. Organic compounds have carbon-hydrogen bonds, while inorganic do not have these bond.
5. Inorganic compounds contain metal atoms, whereas organic compounds do not.
6. Organic compounds are biological and inorganic are mineral in nature.
7. Organic compound are covalent in nature whereas organic compound are both ionic and covalent in nature.
8. Organic compound can form long and complex chain of molecules(hence form polymers) whereas inorganic
compound does not have this capacity.
9. Organic compound are source of energy for human life(as food) whereas inorganic compound act as catalyst.
10. Organic compound are used as main source of energy in modern world(as petroleum oil) whereas inorganic
compound does not.
AGING OF LAKES
Eutrophication means the aging of a lake (to fill in and become land). By adding more nutrients, you will speed the
process. Look at this chart to see the aging process:
CONVERGENT EVOLUTION
Convergent evolution deals with two species from different lineages developing a common characteristic (e.g. bats and
birds developing wings). Mako sharks and Bluefin tuna have no common ancestors, so convergent evolution explains
how the body shape is similar (as it is best for speed).