Lecture 5 cards

Question 1

Formula for photosynthesis

Answer 1

6 CO2 + 6 H2O = C6H12O6 + 6 O2

Question 2

How do we measure primary productivity

Answer 2

O2 evolution or C14 uptake

Question 3

Which increases more with temperature, photosynthesis or respiration?

Answer 3

Respiration, resulting in decrease in net productivity and more carbon dioxide, negative feedback loop, decreased biomass in terrestrial systems also

Question 4

Expected effect of 4C increase in temperature

Answer 4

20% increase in net primary production and 43% increase in oxygen consumption

Question 5

Redfield ratio

Answer 5

106 C : 16 N : 1 P

Question 6

Monod relationship

Answer 6

Formula for direct growth on substrate

Question 7

Michaelis-Menten relationship

Answer 7

General enzyme relationship, how rapidly nutrients get into the cells

Question 8

Droop relationship

Answer 8

Growth on internal substrate

Question 9

Variable internal stores model

Answer 9

2 steps, uptake and utilization (view slide 34)

Question 10

DIP

Answer 10

Dissolved inorganic phosphotous, HPO4(2-). This is what algae use.

Question 11

N2

Answer 11

Dissolved nitrogen gas in equilibrium with the air

Question 12

DIN

Answer 12

Dissolved inorganic nitrogen, NH4(+), NO2(-), NO3(-). Algae use these ions.

Question 13

Nitrate assimilation

Answer 13

NO3(-) to NH4(+), requires energy and nitrate reductase

Question 14

Nitrification

Answer 14

NH4(+) to NO3(-), energy source for bacteria

Question 15

Denitrification

Answer 15

NO3(-) to NO2(-) to N2O to N2. Anaerobic, requires energy-rich organics

Question 16

Nitrogen fixation

Answer 16

N2 to NO3(-), anaerobic, reduced to oxidized form, cyanobacteria

Question 17

Ammonification

Answer 17

Organic matter to NH4(+)

Question 18

Amino acid synthesis

Answer 18

NH4(+) to amino acids

Question 19

Trichodesmium thiebautii

Answer 19

Cyanobacterium in the open ocean, requires moderately warm temperature and non-rough seas. Fixes nitrogen, does not have heterocysts, requires a lot of iron to fix.

Question 20

Sources of nitrogen

Answer 20

Uptake into phytoplankton and bacteria, regeneration of N from food web, upwelling from below mixed layer, primary production

Question 21

Old production of nitrogen

Answer 21

Recycling and regeneration

Question 22

New production of nitrogen

Answer 22

Upwelling and N2 fixation

Question 23

Losses of nitrogen to the atmosphere

Answer 23

Volatilization, denitrification, sedimentation

Question 24

Volatization of nitrogen

Answer 24

NH3

Question 25

HNLP areas

Answer 25

High nutrients low production. Eg gulf of alaska, equatorial pacific ocean, antarctic ocean

Question 26

Critical depth

Answer 26

Point at which total gross photosynthesis of the phytoplankton in the water column equals total respiration

Question 27

Compensation depth

Answer 27

Depth at which the rate of photosynthesis equals the rate of respiration

Question 28

PAR

Answer 28

Photosynthetically active radiation

Question 29

Spring bloom

Answer 29

Caused by increases in light, abundant nutrients that have accumulated over winter period, shallower critical depth. Brought to an end by nutrinet limitation and increases in grazing.

Question 30

Summer recycling

Answer 30

Summer period dominated by recycling

Question 31

Fall bloom

Answer 31

May occur because of breakdown of thermocline and deeper mixing bringing nutrients to the euphotic zone

Question 32

Low light

Answer 32

Declining growth because of declining light