Productivity

2.5.2 Photosynthesis & Respiration

2.5.3 Describe Energy as it moves through Ecosystems

2.5.5 Define Terms of Productivity

2.2.6 & 2.5.7 Calculate Productivity

Photosynthesis - Inputs

carbon dioxide, water, chlorophyll certain visible

wavelengths of light

TO PRODUCE – organic matter oxygen http://www.1ststeps.org/Science/Photosynthesis/

photosynthesis-color.jpg

Photosynthesis – energy transformation

transformation of light energy

into the chemical energy of organic matter

http://www.osovo.com/diagram/phototsynthesis.gif

Respiration - Inputs

organic matter oxygen

TO PRODUCE Carbon dioxide Water

WITHOUT Oxygen carbon dioxide other waste

products are formed http://extension.oregonstate.edu/mg/botany/images/fig24.gif

Respiration - Outputs

Energy is released in a form available for use by living organisms,

but is ultimately lost as heat.

http://ec1.images-amazon.com/images/I/41s3tl36cQL.jpg

Primary Productivity What do “producers” gain?What do “producers” gain? Energy-rich Energy-rich organic compoundsorganic compounds

from from inorganic materialsinorganic materials through through photo- and chemosynthesisphoto- and chemosynthesis

These energy rich compounds can These energy rich compounds can be used in producing more of be used in producing more of themselves either through themselves either through growthgrowth or or reproductionreproduction

ProductionProduction = the incorporation of = the incorporation of energy and materials into the energy and materials into the bodiesbodies of organisms of organisms

http://johnbokma.com/mexit/2005/01/16/nice-group-of-plants.jpg

primary productivity

““the quantity of organic material the quantity of organic material produced, or produced, or solar energy fixedsolar energy fixed, by , by photosynthesisphotosynthesis in green plants per unit in green plants per unit time” (IB definition)time” (IB definition)

Rate at which Rate at which autotrophsautotrophs synthesize synthesize new biomassnew biomass

http://graphics.stanford.edu/courses/cs448c-00-fall/plants.jpghttp://graphics.stanford.edu/courses/cs448c-00-fall/plants.jpg

gross primary productivity (GPP)

Total amountTotal amount of of organic material organic material fixed by autotrophsfixed by autotrophs

Result of Result of photosynthesis (or photosynthesis (or chemosynthesis)chemosynthesis)

COCO22 + H + H220 + light 0 + light

energy energy glucose + glucose + OO22

net primary productivity (NPP)

Rate of production of Rate of production of biomassbiomass potentially potentially available to available to consumersconsumers (herbivores)(herbivores)

Not all of the total Not all of the total productivity (energy) goes productivity (energy) goes into making biomass into making biomass (growth and reproduction)(growth and reproduction)

Some productivity is Some productivity is usedused in the autotroph’s own life in the autotroph’s own life processes (respiration) and processes (respiration) and this energy is ultimately this energy is ultimately lostlost as heatas heat

So, NPP = GPP - RSo, NPP = GPP - R

Productivity Review

Calculating/Measuring Primary Productivity

The FormulaThe Formula NPP = GPP – respiration Gain in energy or biomass per unit

time AFTER respiratory losses GPP less the biomass or energy GPP less the biomass or energy

used by autotrophs in respirationused by autotrophs in respiration Expressed as Expressed as

– Energy Energy per unit area per unit timeper unit area per unit timee.g. J/me.g. J/m22/yr/yr

– BiomassBiomass added per unit area per unit time added per unit area per unit timee.g. g/me.g. g/m22/yr/yr

Light-Dark Bottle Technique Light-Dark Bottle Technique 1.1. Measure OMeasure O22

production inproduction inlight and dark bottleslight and dark bottles

2.2. Light bottleLight bottle: : photosynthesis and photosynthesis and respiration respiration

3.3. Dark bottleDark bottle: : respiration onlyrespiration only

4.4. DetermineDetermine http://krupp.wcc.hawaii.edu/biol200/powerpnt/envrfact/sld013.htm

GPP = Light - Dark GPP = Light - Dark NPP = Light - Initial NPP = Light - Initial Respiration= Initial – DarkRespiration= Initial – Dark

Measuring Primary Productivity

1.1. Harvest methodHarvest method - measure - measure biomass changebiomass change over over time and express as biomass per unit area per time and express as biomass per unit area per unit timeunit timeDestructive!Destructive!

2.2. COCO22 assimilation assimilation - measure - measure COCO22 uptake uptake in in photosynthesis and release by respirationphotosynthesis and release by respiration

– Assume any COAssume any CO22 removed is removed is incorporated incorporated into into organic material by photosynthesisorganic material by photosynthesis

– Use Use dark bottledark bottle to measure respiration in absence of to measure respiration in absence of photosynthesis to get GPPphotosynthesis to get GPP

– COCO2 2 is difficult to measure in aquatic systemsis difficult to measure in aquatic systems

Factors that Affect Primary Productivity

1.1. Solar radiationSolar radiation:: quality (type) of light quality (type) of light quantity of light productivity (to a point when quantity of light productivity (to a point when too much light will inhibit photosynthesis)too much light will inhibit photosynthesis)

2.2. TemperatureTemperature: temp. : temp. productivity (to a point productivity (to a point when high temperatures can denature enzymes)when high temperatures can denature enzymes)

3.3. COCO22: CO: CO22 productivity (since CO productivity (since CO22 is an input) is an input)

4.4. HH22OO: H: H22O productivity (again since HO productivity (again since H22O is an O is an input)input)

More Factors

5.5. NutrientsNutrients: nutrients : nutrients productivity productivity (any food, (any food, chemical element or compound required by an chemical element or compound required by an organism to live, grow and reproduce, e.g. iron, organism to live, grow and reproduce, e.g. iron, magnesium, calcium, nitrate, phosphate, silicate)magnesium, calcium, nitrate, phosphate, silicate)

6.6. HerbivoryHerbivory: grazing of autotrophs by herbivores : grazing of autotrophs by herbivores can can productivity (e.g. sea urchins productivity (e.g. sea urchins ing ing productivity of kelp forest habitat)productivity of kelp forest habitat)

Therefore…

The The leastleast productive productive ecosystems are those with ecosystems are those with limited heat and light limited heat and light energy, limited water and energy, limited water and limited nutrientslimited nutrients

The The mostmost productive productive ecosystems are those with ecosystems are those with high temperatures, lots of high temperatures, lots of water, light and nutrientswater, light and nutrients

secondary productivity

Productivity of consumers The rate of biomass formation or

energy fixation by heterotrophic organisms

http://www.danheller.com/images/LatinAmerica/Ecuador/Galapagos/tortoise-eating-big.jpg

GSP Calculations

Total gain in energy or biomass per unit time

Food eaten – fecal loss

AKA Assimilation

Measuring Secondary Productivity Use an aquarium

– population of invertebrate herbivores (eg brine shrimps)

– or a terrarium population of invertebrate herbivores (eg silkworms)

– feed on a known producer biomass for a period of time.

The remaining food material and feces are collected, dried and weighed.

Net productivity might be measured as the increase in biomass of a consumer population over time.

http://www.drsfostersmith.com/images/Categoryimages/normal/p_27289_36965_aquarium.jpg