L13

Question 1

What is primary production

Answer 1

Primary production is the total amount of carbon (C) in grams that is converted into organic material per square meter of sea surface per year (gC/m2/yr).

Question 2

What factors limit plant growth and reduce primary production

Answer 2

Factors that limit plant growth and reduce primary production include solar radiation and nutrients as major factors and upwelling, turbulence, grazing intensity, and turbidity as secondary factors.

Question 3

How much incoming solar radiation is employed for photosynthesis and stored as energy in organic compounds

Answer 3

0.1-0.2%

Question 4

What is net primary productivity

Answer 4

Net primary productivity is the amount of carbon converted into organic material above that required for the minimal survival of the autotroph. It is the amount of organic material available for growth and reproduction.

Question 5

What is compensation depth and at what depth does it typically occur

Answer 5

Compensation depth is the depth where net primary productivity equals zero. This is usually located where light intensity is about 1 percent of its surface value, which typically occurs at a water depth of ~110 meters in clear water

Question 6

At what temperatures is productivity in the ocean negligible

Answer 6

Productivity is negligible when water temperatures are colder than 0o and warmer than 40o. Between these limits, productivity increases with increasing temperature.

Question 7

what happens to most of the light entering the ocean

Answer 7

d. Most of the light entering the ocean is absorbed and converted into heat.

Question 8

why does productivity increase with latitude

Answer 8

productivity tends to increase with latitude because of the greater availability of nutrients away from the equator.

Question 9

what are macronutrients

Answer 9

Macronutrients are elements or compounds required in large quantities, particularly phosphorus (P), nitrogen (N), and silicon (Si).

Question 10

what macronutrients do phytoplankton require and in what ratio

Answer 10

c. Phytoplankton generally require phosphorus (P), nitrogen (N), and carbon (C) in the ratio of 116C:16N:1P.

Question 11

what are micronutrients

Answer 11

Micronutrients are indispensable elements and compounds used in very small quantities. Because they are needed in small (trace) eg iron copper, manganese, zinc, boron and colbat

Question 12

how to scarcity of macronutrients typically occur

Answer 12

The scarcity of macronutrients typically occurs over a broad region of the ocean and so limits productivity on a regional scale.

Question 13

is carbon abundant in sea water

Answer 13

yes so it is never a limiting factor

Question 14

are nitrogen and phosphorus abundant

Answer 14

they are needed in smaller amounts but due to their demand are less abundant

Question 15

what is usually the limiting factor in productivity

Answer 15

nitrogen

Question 16

what can silicon be a limiting factor to (2) and why

Answer 16

diatoms and silicaflagellates they need silicon to construct their shells

Question 17

how is nutrients from dead organisms released

Answer 17

d. Dead organisms and waste material sink into the deeper water, removing the nutrients they contain from the productive surface zone. Decomposition eventually releases the nutrients into the deep water.
4. Upwelling and turbulence can return nutrients to the surface.

Question 18

what is upwelling

Answer 18

Upwelling is the slow, persistent rising of nutrient-rich water toward the ocean surface

Question 19

give 3 examples of upwelling

Answer 19

-In equatorial waters between the gyres, because Ekman transport causes surface water to diverge, inducing water from below to rise to the surface.
- In coastal waters where persistent wind produces seaward Ekman transport of surface water, thereby promoting upwelling of water.
- Nearshore turbulence generated by storm waves and tidal currents mix nutrient-rich waters upward. This is most pronounced wherever the seafloor is irregular and coastal currents are strong.
.

Question 20

what can the overgrazing of autotrophes lead to

Answer 20

can deplete the population and lead to a decline in productivity

Question 21

how does turbidity restrict productivity

Answer 21

turbidity reduces the depth of light penetration and restricts productivity even if nutrients are abundant.

Question 22

what is productivity like in the tropics and subtropics

Answer 22

1. In the tropics and subtropics, sunlight is abundant, but it generates a strong thermocline that restricts upwelling of nutrients and results in lower productivity. High productivity can occur locally in areas of upwelling between the circulation gyres and at coral reefs.

Question 23

what is productivity like in temperate regions

Answer 23

2. In temperate regions, productivity is distinctly seasonal.

Question 24

what is productivity like in temperate regions winter

Answer 24

In winter, the water column is isothermal and mixes easily, and although nutrients are abundant at the surface, limited sunlight restricts productivity.

Question 25

what is productivity like in temperate region spring

Answer 25

In spring, sunlight becomes more abundant, which triggers a diatom bloom.

Question 26

what is productivity like in temperate region summer

Answer 26

• A thermocline develops and prevents vertical mixing and resupply of nutrients.
• Usage depletes the nutrients in the surface water.
• Grazing by herbivores greatly reduces the population of phytoplankton.

Question 27

what is productivity like in temperate region autumn

Answer 27

In the fall, productivity initially increases as the water becomes isothermal and nutrients again become abundant, but then declines as sunlight diminishes.

Question 28

what range does primary productivity range from:

Answer 28

25 to 1,250 gC/m2/yr

Question 29

what is primary productivity like in the open ocean

Answer 29

In the open ocean, the distribution of productivity resembles a “bull’s-eye” pattern with the lowest productivity located in the center, the highest at the edge of the basin. Water in the open ocean is colored blue because of downwelling, the presence of a permanent strong, deep thermocline, and the near-absence of plankton.

Question 30

what is primary productivity like on the continental shelves

Answer 30

Continental shelves display moderate biological productivity of between 50 and 200 gC/m2/yr, because nutrients wash in from the land and tide- and wave-generated turbulence recycle nutrients from the bottom water.

Question 31

what is primary productivity like in polar areas

Answer 31

Polar areas have high biological productivity because there is no pycnocline to inhibit mixing.

Question 32

what is primary productivity like in equatorial waters

Answer 32

Equatorial waters have high biological productivity in areas of upwelling and low productivity elsewhere because of the presence of a sharp pycnocline

Question 33

what does the word trophic refer to

Answer 33

nutrition

Question 34

what are trophic dynamics

Answer 34

1. Trophic dynamics is the study of the nutritional interconnections among organisms in an ecosystem.

Question 35

what is the formula for photosynthesis

Answer 35

6CO2 + 6H2O + sunlight  C6H12O6 (sugar) + 6O2

Question 36

what is the formula for respiration

Answer 36

C6H12O6 (sugar) + 6O2  6CO2 + 6H2O + energy

Question 37

Basic feeding style: grazers

Answer 37

a. Grazers—consume plant material.

Question 38

Basic feeding style:predators

Answer 38

b. Predators—hunt and kill prey.

Question 39

Basic feeding style:scavengers

Answer 39

c. Scavengers—consume dead organic matter.

Question 40

Basic feeding style:filter feeders

Answer 40

d. Filter feeders—filter the water for suspended food.

Question 41

Basic feeding style: deposit feeders

Answer 41

e. Deposit feeders—selectively or nonselectively consume food that is mixed in the sediments.

Question 42

what type of feeder is bacteria

Answer 42

decomposer

Question 43

what are the two basic types of bacteria

Answer 43

Aerobic bacteria—require free oxygen to respire and decompose dead matter.
Anaerobic bacteria—live in an oxygen-free (anoxic) environment, but obtain oxygen for respiration from other sources, such as SO42– (sulfate ion) and release H2S (hydrogen sulfide gas) as a byproduct of decay

Question 44

what are the two types of autotroph bacteria

Answer 44

Cyanobacteria (blue-green algae) photosynthesize.

b. Chemosynthetic bacteria use chemical energy released in the oxidation of inorganic compounds to produce food.

Question 45

on average how much energy is passed between trophic levels

Answer 45

10-20%