Secondary Production

Jimmy NelsonSES Fall 2012

SECONDARY PRODUCTION WHAT IS IT? WHAT INFLUENCES IT? WHAT DETERMINES PATTERNS OF

ENERGY FLOW THROUGH SECONDARY PRODUCERS AND THUS THROUGH ECOSYSTEMS?

HOW IS SECONDARY PRODUCTION MEASURED?

SECONDARY PRODUCTION

Secondary production is the generation of biomass by HETEROTROPHS (anything that is not a plant) over an interval of time.

Secondary production is typically measured in grams of organic matter or units of organic matter (e.g. C,N,S). Also measured in energy (Kcal).

The transfer of primary production to secondary production is a very “leaky” process.

Energy removed from lower trophic level

Energy Consumed (Gross Intake)

Energy not used

Digested Energy

Egested Energy

Assimilated Energy

Urinary waste

Production:Growth and Reproduction

Maintenance: Respiration and activity

Energy Transfer is NOT 100%

Big Fish Eat the Little Fish

THE CONCEPTOF TROPHIC LEVELS

1

TROPHIC LEVEL

2

3

4

LINDEMAN 1942

0

The thinking Was

Organization By Traits

FOOD WEBS

Ocean Grassland1

2

3

4

3

ENERGY FLOW IN CEDAR LAKE BOGLINDEMAN 1942

TROPHIC LEVEL

NET PRODUC

-TION

PRODUCTION CONSUMED BY NEXT LEVELCONSUMERS

PRIMARY PRODUCER

879

148

PRIMARY CONSUMER

104

31

SECONDARY CONSUMERS

13

0

UNITS ARE KCAL/M2/YR

TROPHIC PYRAMID CONCEPT

ENERGY LOSS UP THE FOOD CHAIN

BIG THINGS EAT LITTLER THINGS

+ =

Trophic pyramids

Consequence of: Energy loss as you go up food webLarger animals tend to eat smaller animals

WHITTAKER ECOLOGICAL MONOGRAPHS 31:157 (1961) Experimental ponds

TROPHIC PYRAMIDS

5001

0.01

40,000410

1

1632

1

210

3

Primary producers

Primary consumer - Herbivores

Secondary Consumers Carnivores Detritivores

BIOMASS PYRAMIDS g Carbon per m2

Grassland(Odum 1957)

Forest(Golley 1960)

Terrestrial Aquatic

Ocean(Riley 1956)

Lake(Ravera 1969)

What limits food webs? 1st Law of Thermodynamics

You can’t get out more energy than you put in

Fixed by plants

2nd Law of ThermodynamicsYou can’t breakeven - energy is lost with

every transaction

PROCESSING CONSUMED ENERGY

Egestion

WHAT DOES AN INDIVIDUAL DO WITH ENERGY?

eges

tion

NET PRODUCTION

Community

INDIVIDUAL: ASSIMILATION EFFICIENCYCARNIVORES

DETRITIVORES

VARIES WITH FOOD QUALITY

• C:N RATIO

• PROTIEN & LIPID CONTENT

ASSIMILATION EFFICIENCY (%)

0-20 20-40 40-60 60-80 80 -100

NUMBER

OF

CONSUMER

S

50302010 0

50302010 0

50302010 0

HERBIVORES

FROM VALIELA 1995

Single cells

INDIVIDUAL: NET PRODUCTION EFFICIENCYVARIES WITH

• TROPHIC LEVEL• METABOLISM• LIFE-STYLE• QUALITY OF

FOOD SOURCE

FROM VALIELA 1995

CARNIVORES 20

10

0

HERBIVORES 20

10

0

20

10

0

DETRITIVORES

0-20 20-40 40-60 60-80 80 -100

PRODUCTION EFFICIENCY (%)1

NUMBER OF

CONSUMERS

MAMMALS & BIRDS 1 - 3 %

FISH & REPTILES 10%

ZOOPLANKTON &INSECTS

40%

Single cells

1Based on growth

HOW MUCH OF THE NET PRODUCTION OF ONE LEVEL IS INGESTED (eaten) BY THE NEXT LEVEL

TROPHICLEVEL

NETPRODUC

-TION

PRODUCTIONINGESTED (eaten) BY

NEXTLEVELCONSUMERS

PRIMARYPRODUCER

879 148

PRIMARYCONSUMER

104 31

SECONDARYCONSUMERS

13 0

UNITS ARE KCAL/M2/YR LINDEMAN 1942

(148/879)*100 = 18 %

ENERGY FLOW IN CEDAR LAKE BOG

ECOSYSTEM: EXPLOITATION EFFICIENCY

EXPLOITATION EFFICIENCY

COMMUNITY PRIMARYPRODUCERS

EXPLOITATIONHERBIVORES

(%)

MATUREDECIDOUSFOREST

TREES & SHRUBS

LARGE AMOUNT OFNONPHOTOSYNTHETICSTRUCTURE

LOW TURNOVER RATE

1 - 3

GRASS -LANDS

HERBACEOUS PLANTS

MODERATESTRUCTURALMATERIAL

MEDIUM TURNOVERRATE

10 - 40

AQUATICOcean or lake

PHYTOPLANKTON

LOW STRUCTURE

VERY HIGH TURNOVER

60 - 99

HOW MUCH OF THE NET PRODUCTION AT ONE TROPHIC LEVEL TURNS INTO NET PRODUCTION AT THE NEXT TROPHIC LEVEL

TROPHICLEVEL

NETPRODUC

-TION

PRODUCTIONCONSUMED BY NEXTLEVELCONSUMERS

PRIMARYPRODUCER

879 148

PRIMARYCONSUMER

104 31

SECONDARYCONSUMERS

13 0

UNITS ARE KCAL/M2/YR LINDEMAN 1942

(13/104)*100=

13 %

ENERGY FLOW IN CEDAR LAKE BOG

ECOSYSTEM: ECOLOGICAL EFFICIENCY

ECOLOGICAL EFFICIENCY = TROPHIC LEVEL = FOOD CHAIN EFFICIENCY

Pauley and Christensen Nature 1995

40

30

20

10

0 2 6 10 14 16 20 24ECOLOGICAL EFFICIENCY (%)

for animals that eat other animals (trophic levels 2 - 6)

N

UM

BE

R

~ 10%

RANGES FROM 2 - 50%

Why are large carnivorous animals so rare ?

HERBIVORES

HUNTERS

MCNABB 1973

40% Exploitation Efficiency5% Growth efficiency20

10% Trophic efficiency

2

1000g C m2 year

Grassland

Gazelle

Lion

HOW DO ATTRIBUTES CHANGE AS YOU MOVE UP THE FOOD WEB?

NUMBER OF SPECIES

POPULATION SIZE REPRODUCTIVE

RATES

BODY SIZE HOME RANGE SEARCHING

ABILITY MAINTENANCE

COSTS ASSIMILATION

EFFICIENCY

PRICE 1975

GO DOWN GO UP

Annual Secondary Production

Ecosystem Type

Net Primary Production (109 metric tons C yr-1)

Animal Consumption

(%)

Net Secondary Production (106 metric tons C yr-1)

TERRESTRIAL 49 7 372 Tropical rain forest 15 7 110

Temperate evergreen forest

3 4 12

Temperate deciduous forest

4 5 19

Temperate grassland 2 10 30

AQUATIC 25 37 1376 Lake and stream 1 20 120

Open ocean 19 40 1140

Upwelling zones 0.1 35 5

Estuaries 1 15 25

BIOSPHERE 74 17 1748

IN THEORY, IT IS THE SAME AS FOR PLANTS --JUST FIGURE OUT HOW MUCH BIOMASS THEY

ACCUMULATE IN A CERTAIN AREA OVER A CERTAIN TIME.

HOW TO ESTIMATE SECONDARY PRODUCTION

How many are there?

How much did they grow? X = Net

Production

-100100300500700

WEI

GH

T O

F IN

DIV

IDU

AL

0 2 4 6 8 10YEAR

=g biomassper m2 per Year

Age or Length

NET PRODUCTION = THE BALANCE BETWEEN GAINS AND

LOSSES

FOR THE FOR THE INDIVIDUAL POPULATION

• GAINS GROWTH BIRTHS

• LOSSES EXCRETION DEATHSRESPIRATION MIGRATIONREPRODUCTION

FOR THE ECOSYSTEM

FOR EACH POPULATIONINTEGRATE OVER A POPULATION COMPRISED

OF INDIVIDUALS OF DIFFERENT SIZES AND PRODUCTION RATES.

NEED TO INTEGRATE:1. THE NUMBER OF INDIVIDUALS AT ANY

GIVEN SIZE2. GROWTH AT SIZE3. REPRODUCTION AT SIZE4. MORTALITY RATES

THEN DO IT AGAIN FOR EVERY SPECIES IN THE ECOSYSTEM

THIS CAN BE DIFFICULT BECAUSE ANIMALS HAVE "BEHAVIOR"

THEY HIDE THEY BITE

SCALING WITH BODY SIZE

ATTR

IBU

TE

WEIGHT of INDIVIDUAL (g)

METABOLISM AND INGESTION

NUMERICAL ABUNDANCE

SCALING WITH BODY SIZE

P/BRatio

Wet weight (g) of individual

(1/yr)

P/B = aW b

Log [WEIGHT of INDIVIDUAL (g)]

Log (P/B)

0.0000000001 0.0001 0.01 1 100 10,000From Banse and Moser 1980

100

10

1

0.1

P/B ratio

P:B RATIO

grams

SUMMARY WHAT IS SECONDARY PRODUCTION?

All production that isn’t by a plant. WHAT INFLUENCES IT?

1st Law of Thermo - Initial energy fixed by plants. 2nd Law Thermo - Losses during processing in the food web.

WHAT INFLUENCES PATTERNS OF ENERGY FLOW THROUGH AN ECOSYSTEM? Fundamental differences between aquatic and terrestrial

environments. Quality of food eaten Metabolism and Allocation of assimilated energy by organisms.

HOW IS SECONDARY PRODUCTION MEASURED? Essentials are the same as for plants only techniques are more

varied.

LAB TODAY

If YOU DOTHIS LAB WELL, YOU WILL GET WET, MUDDY and COLD - Bring Polar fleece, hats, towel, extra clothes.

WEAR SWIMSUITS AND BRING SNORKELING AND FISHING GEAR

Later this week . . . Tomorrow for class - calculate your

own isotope estimate

Thurs - calculate the ecological efficiencies for the beginning of lab

NPP= 100,000

Ingestion2050

Units: Kcal/m2/yr

1000 30 2

Egestion

250

50

Energy LossRespiration

RespirationMigration

RespirationMigrationCaring for youngFood search

17.5150800

200 20 20 0.5

Net Production

I NP NP NPI I

EFFICIENCY (%)

EXPLOITATION

ASSIMILATION

NET PRODUCTION

ECOLOGICAL

PRIMARY PRODUCERS

SECONDARY PRODUCERS

1° consumer 2° consumer 3° consumerHerbivores Carnivores

NPP= 100,000

Ingestion2050

Units: Kcal/m2/yr

1000 30 2

Egestion

250

50escapes

Energy LossRespiration

RespirationMigration

RespirationMigrationCaring for youngFood search

17.5150800

200 20 20 0.5

Net Production

I NP NP NPI I

EFFICIENCY (%)

EXPLOITATION

ASSIMILATION

NET PRODUCTION

ECOLOGICAL

PRIMARY PRODUCERS

SECONDARY PRODUCERS

1° consumer 2° consumer 3° consumerHerbivores Carnivores

2050/100,000 = 2.0 200/250 = 80 20/20 = 100

X 100 = %

(800+250)/2050 = 51.2 (150+20)/200 = 85 (17.5+0.5)/20 = 90

250/1050 = 23.0 20/170 = 11.7 0.5/18 = 2.7

250/100,000 = 0.2 20/250 = 8 0.5/20 = 2.5