Energy and Ecosystems AQA BIOLOGY P2

How can biomass be measured?

. Mass of carbon per given area.

. Dry mass per given area

What do all biomass contain?

Chemical energy store.

What is the chemical energy store?

When is chemical energy store produced?

It is energy stored in the bonds of chemical compounds and is produced during photosynthesis.

How can we estimate the chemical energy store in dry biomass?

Calorimetry

1. Dry biomass is placed within a chamber + burned in oxygen

2. This causes the bonds to break within the biomass releasing chemical energy as heat energy.

3. This causes the temperature of surrounding the water to increase

What is the formula for calcluating the heat energy released per gram of biomass?

Specific heat capacity of water x water volume x temperature change / mass of dry biomass

What is gross primary production (GPP)?

The chemical energy store in plant biomass in a given area of volume.

What is net primary production (NPP)?

The resulting chemical energy store after respiration.

How is net primary production (NPP) calculated?

NPP = GPP - R

NPP - net primary production

GPP - gross primary production

R - respiration

What is the net secondary production (N)?

The chemical energy stored in the biomass of consumers after energy losses due to respiration and waste.

How can we calculate the net secondary production (N)?

N = I - (F+R)

N - net secondary production

I - energy ingested

F - faeces/ urine

R - respiration

How can we calculate the percentage of effiency of energy transfer from one trophic level to another?

Percentage = ( energy available after transfer/ energy available before transfer) x 100

How can farmers increase the percentage efficiency?

1. simplfy food webs

2. reduce respirtory losses