Final-Primary Production

Question 1

Photosynthesis is a function of what variables?

Answer 1

light quantity and quality

Question 2

What is the Redeld Ratio (conceptually and numerically)?

Answer 2

Atomic ratio of carbon, nitrogen and phosphorus found in phytoplankton and throughout the deep oceans

Question 3

What is

eutrophication and what are its causes and consequences?

Answer 3

• caused by excess nutrients

- consequences: algae blooms causing depths of benthic animals, hypoxia (lack of oxygen from increased consumption)

Question 4

In a relative sense, how productive are different ocean communities (i.e., coral
reefs, kelp beds, shelf plankton, open ocean)?

Answer 4

Most productive to least: Coral reefs, kelp beds, shelf plankton, open ocean

Question 5

What organisms are largely responsible for oceanic primary productivity?

Answer 5

phytoplankton (95 %)

Question 6

How does photosynthesis vary as a function of light intensity? How does light
intensity decay with depth?

Answer 6

photosynthesis vs. Light intensity as light intensity increases, more ATP is created increasing photosythetic rate. At high light intensity, photosynthetic rates level out due to other limiting factors including competition between oxygen and carbon dioxide

light intensity with depth exponentially decays with increasing depth
-most light is absorbed or scattered at surface

Question 7

What is the definition of the photic (or euphotic) zone?

Answer 7

Photic Zone depth where the rate of carbon dioxide uptake = rate of carbon dioxide production

Question 8

What is the difference between net and gross primary production?

Answer 8

Gross Production Total Photosynthesis

Net Production* Total Photosynthesis - Respiration

Question 9

What is the compensation depth? How is primary

production is measured?

Answer 9

Compensation Depth Where the rate of photosynthesis = the rate of respiration

Question 10

What is responsible for the seasonality in

primary production at low, middle, and high latitudes?

Answer 10

the amount of light incident at the surface and the degree of mixing

Question 11

Where is
primary production highest in the ocean, and where is it lowest, and
why?

Answer 11

polar oceans- intense mid summer bloom (abundant nutrients, vertical mixing)

• tropical oceans- constant low productivity throughout year, high intensity sunlight year round, density-stratified water (little mixing of nutrients)
• mid latitude oceans- spring and fall blooms, winter -surface water mixing, high nutrients in winter but limited sunlight, summer-zooplankton use nutrients reducing phytoplankton (second, less intense bloom)