Productivity in ecosystem

Productivity in ecosystem

• 2.
  PRODUCTIVITY ● The productivityof an ecosystem refers to the rate of production, i.e., the amount of organic matter accumulated in any unit time. ● Ecosystem productivity represents the total amount of energy (the organic matter) fixed or stored by the autotrophs per unit time in ecosystem . ● Measured as such as grams per square metre per day (g m−2 d−1 ) ● It is of two types: 1. PRIMARY PRODUCTIVITY 2. SECONDARY PRODUCTIVITY
• 3.
  PRIMARY PRODUCTIVITY ➔ Itis the rate at which the the solar energy is stored or trapped by the autotrophs, ➔ In other words the amount of biomass or organic food produced by autotrophs per unit are during the process of photosynthesis. ➔ These plants can make food because they are photosynthetic due to presence of the green pigment chlorophyll. ➔ These are further of two types: 1. GROSS PRIMARY PRODUCTIVITY 2. NET PRIMARY PRODUCTIVITY
• 4.
  GROSS PRIMARY PRODUCTIVITY ❖GROSS means TOTAL PHOTOSYNTHESIS ❖ It represents the total organic matter synthesised by the producers by photosynthesis unit area and time. ❖ It includes the organic matter or basically energy used up during process of respiration, metabolism etc. ❖ It depends on the chlorophyll content ❖ estimated in terms of either chlorophyll content as chl/g dry weight/unit area, or photosynthetic number, i.e., amount of CO2 fixed/g chl/hour.
• 5.
  NET PRIMARY PRODUCTIVITY ●Also known as NET ASSIMILATION ● It is defined as the amount of energy or organic matter stored or fixed at the first trophic level after respiration that is available to the higher trophic levels. ● NPP = GPP - RESPIRATION (OR CELLULAR WORK)
• 7.
  RELATION OF SOLARRADIATION AND PRIMARY PRODUCTIVITY
• 8.
  SECONDARY PRODUCTIVITY ➢ Thisrepresents the energy storage at the consumer level. ➢ The energy resulting from the primary production furnishes the energy provided to the rest of the higher trophic levels. ➢ Some of the energy in the form of food is consumed by herbivores or carnivore which are other eaten by the omnivore . ➢ Much of the ingested food is not assimilated , only 10% of the food is ingested and absorbed rest of it is excreted out from the body.