Unit 7: Ocean and the carbon cycle

Question 1

Physical Pump:

Answer 1

Process that transports carbon from the ocean’s surface to it’s deep layer

Question 2

Two processes that physical process contains:

Answer 2

1) Carbon dioxide is more soluble in cold water.
2) Thermohaline circulation is driven by high density water at high latitudes, which are colder and more saline, therefore sinking and taking carbon to the bottom layer of the ocean.

Question 3

Explanation of physical pump:

Answer 3

Deep water is formed by dense surface waters sinking, so it contains large amounts of dissolved inorganic carbon, as the deep waters would have absorbed more carbon dioxide at the surface due to its density.

These carbon-filled waters can stay trapped in deep ocean currents for thousands of years, until they are brought to coastlines through upwelling.

Question 4

One consequence of upwelling of deep layer water.

Answer 4

In equatorial regions, large amounts of carbon dioxide is released into the atmosphere. This is because the waters that are upwelled contain large amounts of dissolved inorganic carbon. The warm temperatures at the equator cause the density of the waters to decrease, therefore the solubility of the carbon in the water also decreases, which causes the release of carbon dioxide into the atmosphere.

Question 5

Biological Pump:

Answer 5

The ocean’s biologically driven sequestration of carbon from the atmosphere to the deep sea.

Question 6

Phase 1 of biological pump:

Answer 6

The production of fixed carbon by plankton in the euphotic zone. In these surface waters, phytoplankton use carbon dioxide (CO2), Nitrogen(n), and Phosphorus(P) during photosynthesis to make carbohydrates, lipids, and proteins. Some combine Calcium(Ca) and dissolved carbonates(carbonic acid and bicarbonate) to form calcium carbonate(CaCO3) shells.

Question 7

Phase 2 of biological pump:

Answer 7

These phytoplankton then either get eaten by other marine life, or die and begin to sink to the ocean floor. These sinking particles cluster together, increasing the rate at which it sinks, therefore decreasing the chance of predation.

Question 8

Phase 3 of biological pump:

Answer 8

Fixed carbon that is sinking or has sunk to the bottom is re-mineralized by bacteria. These minerals stay in deep waters, until the water rises to the surface through upwelling. Carbon that isn’t re-mineralized is sequestered in the sediment and may stay there for thousands of years, often forming limestone rock.

Question 9

C02 dissolves into sea-water and reacts to form carbonic acid

Answer 9

CO2 + H20 H2CO3 (carbonic acid)

Question 10

After carbonic acid is formed, it splits to form a bicarbonate ion, releasing a hydrogen ion.

Answer 10

H2CO3 HCO3(-) + H(+)

Question 11

Some hydrogen ions react with carbonate ions to form more bicarbonate ions

Answer 11

CO3(2-) + H(+) HCO3(-)

Question 12

Carbonate ions are useful to living organisms as they can be combined with calcium ions to form calcium carbonate

Answer 12

CO3(2-) + Ca(2+) CaCO3

Question 13

How does an increase in acidity affect ocean chemistry

Answer 13

An increase in acidity (due to increased carbon dioxide dissolving) causes an increase in H(+) ions. (H2CO3 HCO3(-) + H(+) ) This means there are more hydrogen ions that will react with carbonate ions to form more bicarbonate ions (CO3(2-) + H(+) HCO3(-) ) This will cause a shortage of CO3(2-) ions for the production of calcium carbonate shells (CO3(2-) + Ca(2+) CaCO3) therefore increasing stress on phytoplankton