Question 1

If the GPP of a forest ecosystem is 350 units per year and the NPP is 100 units per year, what is the respiration rate of the primary producers?

Accepted Answer

The respiration rate of primary producers is calculated as the difference between Gross Primary Productivity (GPP) and Net Primary Productivity (NPP). Therefore, Respiration = GPP - NPP = 350 - 100 = 250 units per year.

Question 2

Harvest techniques would likely be the least problematic for estimations of _______ in _______.

Accepted Answer

Aboveground NPP in temperate grasslands is easier to estimate using harvest techniques because the vegetation is more accessible and less complex compared to belowground biomass or tropical rainforest ecosystems.

Question 3

Suppose that the NEE of a temperate grassland ecosystem is 200 units per month. The respiration by autotrophs is 195 units per month, and the respiration by heterotrophs is 80 units per month. What is the NPP?

Accepted Answer

Net Primary Production (NPP) is calculated by adding the Net Ecosystem Exchange (NEE) to the total respiration (autotrophs and heterotrophs). NPP = NEE + Respiration by autotrophs + Respiration by heterotrophs = 200 + 195 + 80 = 475 units per month.

Question 4

Plant species from resource-_______ environments often have low growth responses to fertilization because these plants typically have _______ intrinsic growth rates.

Accepted Answer

Plants from resource-poor environments often have low intrinsic growth rates, which means they are adapted to survive in conditions with limited resources and thus show low growth responses to fertilization.

Question 5

In which biome would one most likely find the smallest percentage of NPP devoted to roots?

Accepted Answer

In a tropical forest, the climate is warm and wet, which supports a high above-ground biomass and less need for extensive root systems compared to other biomes where water and nutrients are more limiting.

Question 6

According to Schindler's studies of lakes in Ontario, Canada, NPP lake ecosystems are most limited by the supply of

Accepted Answer

Schindler's studies demonstrated that phosphorus is the primary limiting nutrient in freshwater lake ecosystems, leading to increased productivity when added.

Question 7

According to recent studies by Field, the total NPP from aquatic ecosystems is approximately _______ the total NPP from terrestrial ecosystems.

Accepted Answer

The answer of According to recent studies by Field, the...

Question 8

What is the correct ranking in total global NPP of the following terrestrial biomes, from highest to lowest?

Accepted Answer

Tropical savannas have the highest NPP, followed by temperate forests and then crops.

Question 9

In freshwater ecosystems, the presence of descending Hadley cells tends to _______ NPP, and the presence of upwelling cells tends to _______ NPP.

Accepted Answer

Descending Hadley cells are associated with dry conditions, which can decrease NPP in freshwater ecosystems. Upwelling cells bring nutrient-rich water to the surface, which can increase NPP.

Question 10

Which statement about net secondary production is true?

Accepted Answer

Net secondary production is the energy stored in biomass represented by growth and reproduction of consumers. It is typically a small fraction of net primary production (NPP) because energy is lost at each trophic level due to respiration and other metabolic processes.

Question 11

Suppose that heterotrophs ingested 7,500 kilograms of plant biomass over a month's period. Respiration of these heterotrophs was the equivalent of 5,200 kilograms, and they egested 1,400 kilograms. What was the net secondary production?

Accepted Answer

Net secondary production is calculated by subtracting the amount of biomass lost through respiration and egestion from the total ingested biomass. Here, it is 7,500 kg - 5,200 kg - 1,400 kg = 900 kg.

Question 12

Suppose that the net secondary production in a community is 1,600 kilograms. The respiration of heterotrophs is 3,000 kilograms, and the egestion is 800 kilograms. Plant respiration is 6,500 kilograms. How much plant material did the heterotrophs ingest?

Accepted Answer

The answer of Suppose that the net secondary production in...

Question 13

Chemosynthetic bacteria in ocean vent communities use forms of _______ as electron donors to take up carbon dioxide and convert it to carbohydrates.

Accepted Answer

Chemosynthetic bacteria in ocean vent communities often use hydrogen sulfide, a form of sulfur, as an electron donor to fix carbon dioxide into carbohydrates.

Quiz 20: Production