8.2 Primary Production (Net Ecosystem Production)

Question 1

What is the definition of Net Ecosystem Production (NEP)?

Answer 1

• a measure of the total biomass (mass of organisms) accumulated during a given period
  Note: how much growth occurred after respiration, like the energy can go towards grown, maintenance, etc.

Question 2

How to calculate NEP?

Answer 2

GPP minus the total respiration of all organisms (producers and consumers) in an ecosystem
- consumers are different from NPP

Question 3

How is NEP estimated by? (2)

Answer 3

• comparing the net flux of CO2 and O2 in an ecosystem, two molecules connected by photosynthesis
• the release of O2 by a system is an indication that is also storing CO2 (O2 is being converted to macros)

Question 4

In aquatic organisms, what controls primary production?

Answer 4

1. Light and nutrients

- note that it is most important in having strong producer trophic level

Question 5

Why does light and nutrients affect primary production in aquatic organisms?

Answer 5

• depth of light penetration of an ocean or lake

- nutrients limits primary production more than light (amount of light is insignificant if not enough nutrients)

Question 6

What must be added for primary production to increase in an area? (2)

Answer 6

• limiting nutrient is the element that must be added

- nitrogen and phosphorus most often limit marine production

Question 7

What limits primary production in terrestrial ecosystems?

Answer 7

Temperature and moisture affect production on a large scale

Question 8

Why does temperature and moisture affect primary production in terrestrial ecosystems?

Answer 8

• primary production increases with moisture. Which is affected by precipitation accumulation, temperature and solar energy