Ecology- Primary Production

Question 1

How much of the earth’s o2 comes from the ocean?

Answer 1

50-80%

Question 2

What is an ecosystem a total of?

Answer 2

• biota (all living organisms)

- abiota (chemical properties and physical properties in a limited area)

Question 3

Autotroph

Answer 3

Primary producers which use inorganic material and/or create energy from sunlight.

Question 4

Heterotroph (2 types)

Answer 4

Consumers which eat other organisms. Herbivores eat plant material, Carnivores eat animals and omnivores eat both.

Decomposers (reducenten) eat dead organic material and convert it into inorganic matieral.

Question 5

Photosynthesis Equation

Answer 5

6CO2 (carbon dioxide) + 6H2O (water) + sunlight → C6H12O6 (glucose –> sugar) + 6O2 (oxygen)

Question 6

What are the primary producers?

Answer 6

• microalgae
• macroalgae
• marine plants (e.g. mangroves and seagrass)
• korals?

Question 7

What is needed for primary producer growth?

Answer 7

• water
• co2
• light
• nutrients

Question 8

Different forms of producers: air contains little water and nutrients

Answer 8

1. bound to soil
2. mutual competition for light
3. Woody structure for firmness

Question 9

Different forms of producers: in water, light is limited

Answer 9

1. nutrients, water and co2 in watercolomn

2. bound to the photic zone (no soil/substrate within reach)

Question 10

Different forms of producers: algae cells are heavier than water

Answer 10

1. high frictional resistance (wrijvingsweerstand) as a result of large surface area: content ratio
2. fat storage in the cell
3. sometimes a little mobility
4. hope for water movement (otherwise they sink!)

Question 11

Respiration Equation

Answer 11

C6H12O6 (glucose –> sugar) + 6O2 (oxygen) = 6CO2 (carbon dioxide) + 6H2O (water) + Energy

Question 12

Net Primairy Production Equation

Answer 12

Photosynthesis - respiration

Question 13

NPP on the coast

Answer 13

high

Question 14

NPP in the middle of the ocean

Answer 14

low

Question 15

NPP in the tropics

Answer 15

low

Question 16

NPP in the polar regions

Answer 16

low

Question 17

Compensation depth

Answer 17

The depth at which primary production equals respiration. This coincides with the depth in the ocean where light is between 0.1-1% of light entering the ocean at the surface. Light decreases rapidly in a water column as a result of absorption and reflection. NPP here is 0.

Question 18

Limiting factors: Is water a limiting factor?

Answer 18

no

Question 19

Limiting factors: Is carbon dioxide a limiting factor?

Answer 19

no

Question 20

Limiting factors: is light a limiting factor?

Answer 20

sometimes

Question 21

Limiting factors: Is N (nitrogen–> stikstof) a limiting factor?

Answer 21

often

Question 22

Limiting factors: Is P (phosphorus) a limiting factor?

Answer 22

sometimes

Question 23

Limiting factors: Is Si (silicon) a limiting factor?

Answer 23

Only with diatoms

Question 24

Limiting factors: Is Fe (iron), K (potassium), etc. limiting factors?

Answer 24

Locally

Question 25

Nutrients in the deep sea/ bottom of the ocean. How do they get there and what does it mean?

Answer 25

Dead organic material sinks below and comes to the deep sea. Animal decomposition then takes place through the decomposers. As a result, deep water is often more nutrient-rich that surface water.

Question 26

How does the deep water return to the surface?

Answer 26

1. Mixing of water layers through waves, tide and currents

2. upwelling

Question 27

Upwelling

Answer 27

the continuous emergence of nutrient-rich(er) water from the deep sea. Two locations:

1. equatorial upwelling
2. coastal upwelling

Question 28

Thermocline

Answer 28

separation of water layers through temperature

Question 29

Permanent thermocline

Answer 29

prevents mixing of water layers. ensures low nutrient availability (but also prevents mixing beyond the photic zone). Exists in tropic zones where the surface water is relatively, strongly warm.

Question 30

Productivity in the tropics

Answer 30

nutrient poor as a result of the thermocline. Low NPP, but locally high NPP through both upwellings.

Question 31

Productivity in temperate (gematigde) areas

Answer 31

variation in nutrient supply. Seasonally bound NPP through light and nutrient availability.

Question 32

Productivity in Polar regions

Answer 32

Nutrient rich. Strongly seasonally bound NPP as a result of light limitations.

Question 33

Tilapia Sterfte Case

Answer 33

In Asia there is a lot of aquaculture of Tilapia. In a certain lake there is high fish mortality. The fish seem to especially die at the end of the night.