Primary Productivity 1.8

PP

rate that solar energy is converted into organic compounds via photosyntheisi over a unit of time (kcal, m2, and yr)

• rate of photosynthesis of all plants in an area over a given time period

kcal

energy

m2

area

yr

length of time

High PP

high plant growth = lots of food and shelter for animals (high biodiversity)

Respiration Loss (RL)

Plants use up some energy they generate via photosythesis by cell respiration

Gross PP (GPP)

Total amount of sun energy that plants capture and convert to energy thru photosyn.

Net PP (NPP)

Amount of energy/biomass leftover after plants have used some thru RL

Equation for NPP

GPP - RL = NPP

Ecological Effieciencey

portion of incoming solar energy that is captured by plants and animals into biomass ( Net PP or food avaliable for consumers)

• 1% of captured by producers

• 99% is lost

• 60% of this is lost to RL

• 40% of this GPP supports thru growth and repoduction of producers

0.4% of solar energy becomes NPP

Trend in Productivity

• the more productice a biome, the more biodiversoty

• water avaliablitiy, higher temp., and nutrient avaliablility all play a role (shortage of any leads to low PP)

Ex. desert (low H2O and nutrients)