Week 3 Part 1

Question 1

What are the two variables in all the hypotheses of biodiversity

Answer 1

Degree of overlap in ecological function of species
Variation in strength of ecological functions of species

Question 2

What is the complementarity hypothesis

Answer 2

As species richness increases there will be a linear increase in community function. Each species added has an equal effect

Question 3

What is the redundancy hypothesis

Answer 3

The functional contribution of additional species reaches a threshold. As more species are added there is an overlap in their function or redundancy among species.

Question 4

What is the dirver and apssenger hypothesis

Answer 4

Strength of ecological function varies greatly “Driver” species have a larger effect; “passenger” species have a minimal effects

Question 5

What is the variation on the driver and hypothesis

Answer 5

It assumes there could be overlap between dirver and passenger functions

Question 6

What is primary production

Answer 6

The chemical energy generated by autotrophs during photosynthesis and chemosynthesis

Question 7

What is primary productivity

Answer 7

Rate of primary production

Question 8

What is the currency used to measure primary production

Answer 8

Carbon because energy assimilated by autotrophs is stored as carbon compounds in plat tissues

Question 9

What is GPP

Answer 9

The total amount of carbon fixed by autotrophs

Question 10

What does GPP depend on

Answer 10

Photosynthetic rate

Question 11

What is photosynthetic rate influence by

Answer 11

Climate and leaf area index

Question 12

What is LAI

Answer 12

Leaf area per uint of ground area. Can be greater than one because of overlapping leaves

Question 13

What is leaf area index

Answer 13

The incremental gain in photosynthesis for each added leaf layer decreases because of shading

Question 14

Does the leaf index increase by the same incriments each time

Answer 14

No eventually the respiratory costs associated with adding leafs outweight the photosynthetic benefits leafs also start to overlap so you are getting less and less sunlight

Question 15

How much carbon fixed do they use in photosyntheis for cellular respiration

Answer 15

Half

Question 16

Are all tissues photosyntehtic

Answer 16

NO

Question 17

What does respiration rate increase with

Answer 17

Temperature so tropical forests have higher respiratory losses

Question 18

What is NPP

Answer 18

Net reprsents biomass gained by the plant esseintaly is the energy left for plant growth and for consumption by detritivores and herbivores
NPP= GPP-Respiration

Question 19

What is a good indicator of ecosystem health

Answer 19

NPP

Question 20

In terrestrial ecosystems how do you measure NPP

Answer 20

The increase in plant biomass usually uses harvest techniques measure biomass before and after growing season

Question 21

What corrections need to be made for measuring NPP

Answer 21

Herbivory and mortality

Question 22

Why is measuring below-ground NPP more difficult

Answer 22

Fine root turn over more quickly than shoots- they die and are replaced quickly
Roots may excude carbon into the soil or bacterial symbionts
Harvests must be more frequent and additional correction factors are needed.

Question 23

What else could measure NPP

Answer 23

Chlorophyll concentration can be a proxy GPP and NPP which can be estimated using remote sensing methods that measure reflection of solar radiation

Question 24

What is NDVI

Answer 24

A commonly used estimate of productivity based on reflection
Can esitmate CO2. NPP, Deforestation, desertification and other phenomena

Question 25

What has a high and low NDVI

Answer 25

Vegetation has a high level and water and soil has a low NDVI value

Question 26

What is NEE

Answer 26

The net change in CO2 is GPP minus total respiration

Question 27

What is more refined esitmate of ecosystem of carbon storage

Answer 27

NEE over NPP

Question 28

Equation for NEE

Answer 28

GPP-(AR+HR)

Question 29

What is the variation of NPP correlated with

Answer 29

Climate NPP increases as percipitation increases up to a point but when there is too much percipation too much cloud cover so less light NPP increases with increasing average annual temperature

Question 30

Why is there variation in the temperature graph

Answer 30

Perceptation varries ammount of sun they reccive wind soil factors (abiotic features that are not related to climate)

Question 31

What tends to determine NPP in terrestrial ecosystems

Answer 31

Nitrogen

Question 32

What was the theme with fertilization and plants in different levels resource communities

Answer 32

Plants from resource poor communities tend to have low growth rates and require less nutrients so they respond less to fertilization than plants from resource rich communities (rich get richer)

Question 33

What happens in nutrient-poor communites are fertilized

Answer 33

Often a change in species composition

Question 34

What is NPP limited by in aquatic ecosystems

Answer 34

Phosphorus and nitrogen

Question 35

How is NPP measured in Aquatic systems

Answer 35

Change in chlorophyll concentration or number of phytoplankton cells

Question 36

What happened in the study of the great lakes and adding more nutrients

Answer 36

Results showed that phosphorus was the nutrient in limited phosphorus it resulted in massive increases in cyanobacteria

Question 37

Where did most of the nutrients come from in rivers and streams

Answer 37

NPP is usally low so it comes from terrestrial organic matter the water flow limits phytoplankton growth; most NPP is from macrophytes and attached algae

Question 38

In the ocean what is NPP limited by

Answer 38

Nitrogen but near the equator it appears to be limited by iron

Question 39

What do scientist think iron fertilization could do and would it work

Answer 39

Reduce global warming because CO2 uptake by phytoplankton would increase. However a large-scale fertizaltion of ocean is unlikely to be a solution the CO2 taken up by phytoplnakton is returned to the atmosphere via respiration of zooplankton and bacteria and iron sinks to the bottom

Question 40

Where is average rates of NPP higher

Answer 40

Land surface is higher than the oceans and found in the tropics

Question 41

Why is there variation of NPP in aquatic ecosystems

Answer 41

Variation of nutrient inputs NPP peaks at mid latitudes where ones of upwelling are found which than can bring nutrient rich deep water to the surface