Secondary Production
Jimmy Nelson
SES 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 Transfer is NOT 100%
Energy removed from lower
trophic level
Energy not used
Egested Energy
Energy Consumed (Gross
Intake)
Digested
Energy
Urinary
waste
Assimilated
Energy
Maintenance:
Production:
Respiration and activity
Growth and Reproduction
Big Fish Eat the Little Fish
THE CONCEPTOF TROPHIC LEVELS
TROPHIC
LEVEL
0
1
LINDEMAN
1942
2
3
4
The thinking Was
Organization By Traits
FOOD WEBS
4
33
2
Ocean
1
Grassland
ENERGY FLOW IN CEDAR LAKE BOG
LINDEMAN 1942
TROPHIC
LEVEL
NET
PRODUC
-TION
PRODUCTION
CONSUMED BY NEXT
LEVELCONSUMERS
879
148
PRIMARY
CONSUMER
104
31
SECONDARY
CONSUMERS
13
0
PRIMARY
PRODUCER
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 web
Larger animals tend to eat smaller animals
TROPHIC PYRAMIDS
WHITTAKER ECOLOGICAL MONOGRAPHS 31:157 (1961) Experimental ponds
BIOMASS PYRAMIDS
g Carbon per m2
Terrestrial
0.01
1
500
Aquatic
1
1
10
4
40,000
3
32
10
16
2
Grassland
Forest
Ocean
Lake
(Odum 1957)
(Golley 1960)
(Riley 1956)
(Ravera 1969)
Primary producers
Primary consumer Herbivores
Secondary Consumers
Carnivores
Detritivores
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 Thermodynamics
 You can’t breakeven - energy is lost with
every transaction
PROCESSING CONSUMED ENERGY
Egestion
WHAT DOES AN INDIVIDUAL DO WITH
ENERGY?
Community
NET PRODUCTION
INDIVIDUAL: ASSIMILATION EFFICIENCY
50
30
20
10
0
NUMBER OF
CONSUMERS
50
30
20
10
0
50
30
20
10
0
CARNIVORES
VARIES WITH
FOOD QUALITY
HERBIVORES
• C:N RATIO
DETRITIVORES
Single
cells
• PROTIEN & LIPID
CONTENT
0-20 20-40 40-60 60-80 80 -100
ASSIMILATION EFFICIENCY
(%)
FROM VALIELA 1995
INDIVIDUAL: NET PRODUCTION EFFICIENCY
VARIES WITH
CARNIVORES
20
• TROPHIC LEVEL
• METABOLISM
• LIFE-STYLE
• QUALITY OF FOOD
SOURCE
10
0
NUMBER OF
CONSUMERS
20
HERBIVORES
10
Single
cells
0
20
DETRITIVORES
10
0
0-20 20-40 40-60
MAMMALS & BIRDS
1-3%
FISH & REPTILES
10%
ZOOPLANKTON &
INSECTS
40%
60-80 80 -100
PRODUCTION EFFICIENCY (%)1
FROM VALIELA 1995
1Based
on growth
ECOSYSTEM: EXPLOITATION EFFICIENCY
HOW MUCH OF THE NET PRODUCTION OF ONE LEVEL
IS INGESTED (eaten) BY THE NEXT LEVEL
ENERGY FLOW IN CEDAR LAKE BOG
TROPHIC
LEVEL
NET
PRODUC
-TION
PRODUCTION
INGESTED (eaten) BY
NEXT
LEVELCONSUMERS
PRIMARY
PRODUCER
879
148
PRIMARY
CONSUMER
104
31
SECONDARY
CONSUMERS
13
0
(148/879)*100 =
18 %
UNITS ARE KCAL/M2/YR LINDEMAN 1942
EXPLOITATION EFFICIENCY
COMMUNITY
MATURE
DECIDOUS
FOREST
PRIMARY
PRODUCERS
EXPLOITATION
HERBIVORES
(%)
TREES & SHRUBS
LARGE A MOUNT OF
NONPHOTOSYNTHETIC
STRUCTURE
1 - 3
LOW TURNOVER RATE
GRASS LANDS
HERBACEOUS PLANTS
MODERATE
STRUCTURAL
MATERIAL
10 - 40
MEDIUM TURNOVER
RATE
AQUATIC
Ocean or lake
PHYTOPLANKTON
LOW STRUCTURE
VERY HIGH TURNOVER
60 - 99
ECOSYSTEM: ECOLOGICAL EFFICIENCY
HOW MUCH OF THE NET PRODUCTION AT ONE
TROPHIC LEVEL TURNS INTO NET PRODUCTION AT
THE NEXT TROPHIC LEVEL
ENERGY FLOW IN CEDAR LAKE BOG
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 LINDEMAN 1942
(13/104)*100=
13 %
ECOLOGICAL EFFICIENCY
= TROPHIC LEVEL = FOOD CHAIN EFFICIENCY
40
NUMBER
30
20
~ 10%
10
2 6 10 14 16 20 24
ECOLOGICAL EFFICIENCY (%)
for animals that eat other
animals (trophic levels 2 - 6)
RANGES FROM 2 - 50%
0
Pauley and Christensen Nature 1995
Why are large carnivorous animals so rare ?
g C m2 year
1000
Grassland
20
40% Exploitation
Efficiency
5% Growth
efficiency
HUNTERS
Gazelle
10%
Trophic
efficiency
HERBIVORES
2
Lion
MCNABB 1973
HOW DO ATTRIBUTES CHANGE AS YOU MOVE UP
THE FOOD WEB?
GO DOWN



NUMBER OF SPECIES
POPULATION SIZE
REPRODUCTIVE
RATES
GO UP





BODY SIZE
HOME RANGE
SEARCHING ABILITY
MAINTENANCE
COSTS
ASSIMILATION
EFFICIENCY
PRICE 1975
Annual Secondary Production
Ecosystem
Type
Net Primary
Production
(109 metric
tons C yr-1)
TERRESTRIAL
49
7
372
Tropical rain forest
15
7
110
Temperate evergreen
forest
Temperate deciduous
forest
Temperate grassland
3
4
12
4
5
19
2
10
30
AQUATIC
25
Animal
Consumption
(%)
37
Net Secondary
Production
(106 metric
tons C yr-1)
1376
Lake and stream
1
20
120
Open ocean
19
40
1140
Upwelling zones
0.1
35
5
1
15
25
Estuaries
BIOSPHERE
74
17
1748
HOW TO ESTIMATE SECONDARY PRODUCTION
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.
X
WEIGHT OF INDIVIDUAL
How many
are there?
How much
did they grow?
700
500
300
100
-100
0
Net
Production
=
=
2
4 6 8 10
YEAR
Age or Length
g biomass
per m2
per Year
NET PRODUCTION =
THE BALANCE BETWEEN GAINS AND
LOSSES
FOR THE
INDIVIDUAL
FOR THE
POPULATION
• GAINS
GROWTH
BIRTHS
• LOSSES
EXCRETION
DEATHS
RESPIRATION MIGRATION
REPRODUCTION
FOR THE ECOSYSTEM
FOR EACH POPULATION
INTEGRATE OVER A POPULATION COMPRISED OF
INDIVIDUALS OF DIFFERENT SIZES AND
PRODUCTION RATES.
NEED TO INTEGRATE:
1. THE NUMBER OF INDIVIDUALS AT ANY
GIVEN SIZE
2. GROWTH AT SIZE
3. REPRODUCTION AT SIZE
4. 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
ATTRIBUTE
NUMERICAL
ABUNDANCE
METABOLISM
AND
INGESTION
WEIGHT of INDIVIDUAL (g)
SCALING WITH BODY SIZE
Log (P/B)
P/B
Ratio
(1/yr)
b
P/B = aW
weight
(g) of (g)]
LogWet
[WEIGHT
of INDIVIDUAL
individual
P:B RATIO
P/B
ratio
100
10
1
0.1
0.0000000001
0.0001
0.01
grams
1
100
10,000
From Banse and Moser 1980
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
PRIMARY
PRODUCERS
SECONDARY PRODUCERS
Herbivores
1° consumer
Carnivores
2° consumer
3° consumer
NPP=
100,000
Respiration
Migration
Caring for young
Food search
Respiration
Migration
Respiration
Energy Loss
800
Ingestion
2050
Net
Production
NP
I
250
Units: Kcal/m2/yr
17.5
I
NP
200
20
I
NP
20
0.5
Egestion
50
1000
EFFICIENCY (%)
EXPLOITATION
ASSIMILATION
NET PRODUCTION
ECOLOGICAL
150
30
2
PRIMARY
PRODUCERS
SECONDARY PRODUCERS
Herbivores
1° consumer
Carnivores
2° consumer
3° consumer
NPP=
100,000
Respiration
Migration
Caring for young
Food search
Respiration
Migration
Respiration
Energy Loss
800
Ingestion
2050
I
Net
Production
NP
I
250
200
NP
20
50
escapes
1000
I
NP
20
0.5
30
2
2.0
200/250 = 80
20/20 = 100
(800+250)/2050 = 51.2
(150+20)/200 = 85
EFFICIENCY (%)
X 100 = %
2050/100,000 =
EXPLOITATION
NET PRODUCTION
ECOLOGICAL
17.5
Egestion
Units: Kcal/m2/yr
ASSIMILATION
150
250/1050 = 23.0
250/100,000 =
0.2
(17.5+0.5)/20 = 90
20/170 = 11.7
0.5/18 =
2.7
20/250 = 8
0.5/20 =
2.5