1 / 22

Secondary Production

Secondary Production. Energy Removed From Lower Trophic Level. Energy Not Used. Gross Energy Intake. Egested Energy . Digested Energy . Urinary Waste . Assimilated Energy. Resting Energy. Activity . Growth. Reproduction. ‘Maintenance’ (or respiration). ‘Production’.

coy
Download Presentation

Secondary Production

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Secondary Production

  2. Energy Removed From Lower Trophic Level Energy Not Used Gross Energy Intake Egested Energy Digested Energy Urinary Waste Assimilated Energy Resting Energy Activity Growth Reproduction ‘Maintenance’ (or respiration) ‘Production’

  3. C = (Mr + Ma + SDA) + (F + U) + (Gs + Gr) Metabolism Waste Growth Energy Budget Maintenance Net Production C = rate of energy consumption Mr = standard metabolic rate (resting energy) Ma = metabolic rate increase due to activity (above Mr) SDA = metabolic rate increase due to specific dynamic action (digestion) F + U = waste losses due to egestion (feces) and excretion (urine) rates Gs = somatic growth rate due to protein synthesis and lipid deposition Gr = growth rate due to gonad (reproductive) synthesis

  4. Energy partitioning is not equal among species and can change depending on season.

  5. Herbivorous mammals: Log (FMR) = 0.774 + 0.727(log body mass) Larger animals require more energy Mammals and birds (warm blooded) need more than reptiles (cold blooded)

  6. First Trophic Level Second Trophic Level Third Trophic Level Fourth Trophic Level Producers (plants) Primary consumers (herbivores) Secondary consumers (carnivores) Tertiary consumers (top carnivores) Heat Heat Heat Heat Solar energy Heat Heat Heat Detritvores (decomposers and detritus feeders) Trophic Levels

  7. Measuring Net Production • Production = + • Need to estimate change in biomass, natality (birth rate), and loss due to death (including harvesting) or emigration net change in biomass losses by mortality

  8. Net Productivity of species n Production Efficiency = Assimilation of species n Why the difference?  Homeothermy (it takes a lot of energy to keep warm)

  9. Net Production at trophic level i + 1 Trophic Efficiency = Net production at trophic level i Energy not transferred is lost as respiration or to detritus. For aquatic systems, average ~ 10.

  10. How much primary production is required to support a particular fishery? Tuna are top predators operating at trophic level 4. In 1990 2,975,000 tons of tuna were taken. This is equivalent to 0.1 g carbon per m2 of open ocean per year!!!! How much production is needed to sustain this fishery assuming a 10% transfer efficiency? Need 1.0 g pelagic fish, 10 grams zooplankton, and 100 grams of phytoplankton per m2/year of open ocean to support this fishery – and this is just harvested tuna!!!!! Tuna 0.1 Pelagic Fishes 1.0 Zooplankton 10 Phytoplankton 100

  11. When all of the data for worldwide fisheries are aggregated, on average 8% of global aquatic primary production is being used to produce the global fisheries catch. But, production varies with ecosystem type:

  12. Estimates of Energy Flow in a Temperate Deciduous Forest

  13. Aquatic ecosystem herbivores consume a higher fraction of the primary production than in terrestrial ecosystems (red arrows = average)

  14. Herbivory

  15. Low Ecological Efficiency • Organisms at the base of the food web are much more abundant than those near the top • Eltonian pyramid – a diagram demonstrating the number, biomass, or energy distributions across size classes

  16. Heat Heat Heat Tertiary consumers (human) Decomposers 10 Secondary consumers (perch) Heat 100 Primary consumers (zooplankton) 1,000 Heat Producers (phytoplankton) 10,000 Usable energy Available at Each tropic level (in kilocalories)

  17. Biomass Why does the ocean have such a low biomass of primary producers?

  18. Phytoplankton such as diatoms reproduce by dividing and can divide every few hours. • Because of their fast population growth rate, they are able to support a large number of primary consumers. • Plants are the primary producers in an abandoned field. • Have a much longer lifespan than phytoplankton • Need a much larger biomass of plants to support the primary consumers.

  19. Number of Organisms Why does a temperate forest have so few individual primary producers compared to a grassland?

  20. In a temperate forest, a single tree can support many primary consumers because of its large size. • It takes a lot of individual grasses to = the biomass of a large tree. Number of Organisms

  21. Limits to Secondary Primary Production • Primary production is an obvious limiter • Also include the 2nd law of thermodynamics Above ground PP and herbivore biomass

  22. Carrying Capacity – the number or weight of animals of a single or mixed population that can be supported permanently on a given area • Ecological Carrying Capacity – maximum density of animals that can be sustained without inducing negative effects on vegetation • Economic Carrying Capacity – density of animals that enables maximal sustained harvesting and is always lower than the ecological carrying capacity

More Related