POC & POC Flux

Question 1

Flux

Answer 1

The amount of stuff that goes through a particular area.

Question 2

Attenuation

Answer 2

How quickly POC drops off (Amount of reduction)

Question 3

Remineralization

Answer 3

The process of organic carbon turning into CO2.

Question 4

How does POC quality change with depth?

Answer 4

The quality of POC decreases as you get deeper due to grazing and sloppy feeding of organisms near surface levels.

POC goes through remineralization in surface depths. Then POC undergoes attenuation as it sinks with depth.

Question 5

How does POC Flux change with depth?

Answer 5

The amount of POC in the ocean decreases as the depths get greater.

Question 6

Export Flux

Answer 6

The amount of organic carbon that sinks below 100m (Euphotic Zone)
- Remineralization can occur

Question 7

Sequestration Flux

Answer 7

The amount of organic carbon that sinks at about 1000m (Mesopelagic Zone)

Question 8

How does POC relate to the Biological Pump?

Answer 8

The amount of POC sinking represents strength of Biological Pump.

Question 9

Martin Curve Equation/Definition

Answer 9

Flux z = F100 * (z/100)^-b

Flux z = Flux at Depth z
F 100 = Flux at 100m
z = depth
b = attenuation coefficient

The Martin Curve is a power law that describes the export of POC to the ocean floor.

x axis = POC flux ; y axis = depth (m)

Question 10

Why does the shape of the POC flux curve matter?

Answer 10

The POC flux represents the amount of CO2 that gets sequestered in the deep ocean.

The amount of POC sinking out of surface ocean represents the strength of the Biological Pump, which helps regulate atmospheric CO2 concentrations and provides food for organisms of deeper depths.

• Demonstrates efficiency of Biological Pump; the higher attenuation is, the lower the efficiency of Biological Pump is.

Question 11

What are factors that influence shape of POC flux curve?

Answer 11

Particle Size & Density; Reactivity (Labile versus Refractory); Temperature; Microbial Interactions; Biomass Production

Question 12

How is POC/POC Flux Measured?

Answer 12

Sediment Traps ! Amount of carbon is collected into sediment trap and can be measurable as a mass. Area of the trap is also included in calculating flux. (As well as time—how long it took)

Question 13

Particulate Organic Carbon

Answer 13

Any organic carbon that is caught in a 0.7 micrometer filter.

(Phytoplankton, Zooplankton, Large Bacteria)