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 HETEROTROPHS  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 LINDEMAN

The thinking Was

Organization By Traits

FOOD WEBS Ocean Grassland

ENERGY FLOW IN CEDAR LAKE BOG LINDEMAN 1942 UNITS ARE KCAL/M 2 /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

WHITTAKER ECOLOGICAL MONOGRAPHS 31:157 (1961) Experimental ponds TROPHIC PYRAMIDS

, Primary producers Primary consumer - Herbivores Secondary Consumers Carnivores Detritivores BIOMASS PYRAMIDS g Carbon per m 2 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 Thermodynamics You can’t breakeven - energy is lost with every transaction

PROCESSING CONSUMED ENERGY Egestion

WHAT DOES AN INDIVIDUAL DO WITH ENERGY? egestion NET PRODUCTION Community

INDIVIDUAL: ASSIMILATION EFFICIENCY CARNIVORES DETRITIVORES VARIES WITH FOOD QUALITY C:N RATIO PROTIEN & LIPID CONTENT ASSIMILATION EFFICIENCY (%) NUMBER OF CONSUMERS HERBIVORES FROM VALIELA 1995 Single cells

INDIVIDUAL: NET PRODUCTION EFFICIENCY VARIES WITH TROPHIC LEVEL METABOLISM LIFE-STYLE QUALITY OF FOOD SOURCE FROM VALIELA 1995 CARNIVORES HERBIVORES DETRITIVORES PRODUCTION EFFICIENCY (%) 1 NUMBER OF CONSUMERS MAMMALS & BIRDS % FISH & REPTILES 10% ZOOPLANKTON & INSECTS 40% Single cells 1 Based on growth

HOW MUCH OF THE NET PRODUCTION OF ONE LEVEL IS INGESTED ( eaten ) BY THE NEXT LEVEL UNITS ARE KCAL/M 2 /YR LINDEMAN 1942 (148/879)*100 = 18 % ENERGY FLOW IN CEDAR LAKE BOG ECOSYSTEM: EXPLOITATION EFFICIENCY

EXPLOITATION EFFICIENCY

HOW MUCH OF THE NET PRODUCTION AT ONE TROPHIC LEVEL TURNS INTO NET PRODUCTION AT THE NEXT TROPHIC LEVEL UNITS ARE KCAL/M 2 /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 ECOLOGICAL EFFICIENCY (%) for animals that eat other animals (trophic levels 2 - 6) NUMBER ~ 10% RANGES FROM %

Why are large carnivorous animals so rare ? HERBIVORES HUNTERS MCNABB % Exploitation Efficiency 5% Growth efficiency 20 10% Trophic efficiency g 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

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 WEIGHT OF INDIVIDUAL YEAR = g biomass per m2 per Year Age or Length

NET PRODUCTION = THE BALANCE BETWEEN GAINS AND LOSSES FOR THE INDIVIDUALPOPULATION GAINSGROWTHBIRTHS LOSSESEXCRETIONDEATHS RESPIRATIONMIGRATION 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 WEIGHT of INDIVIDUAL (g) METABOLISM AND INGESTION NUMERICAL ABUNDANCE

SCALING WITH BODY SIZE Log [WEIGHT of INDIVIDUAL (g )] Log (P/B)

,000 From Banse and Moser 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 Ingestion 2050 Units: Kcal/m2/yr Egestion Energy Loss Respiration Migration Respiration Migration Caring for young Food search Net Production I NP I I EFFICIENCY (%) EXPLOITATION ASSIMILATION NET PRODUCTION ECOLOGICAL PRIMARY PRODUCERS SECONDARY PRODUCERS 1° consumer2° consumer3° consumer HerbivoresCarnivores

NPP= 100,000 Ingestion 2050 Units: Kcal/m2/yr Egestion escapes Energy Loss Respiration Migration Respiration Migration Caring for young Food search Net Production I NP I I EFFICIENCY (%) EXPLOITATION ASSIMILATION NET PRODUCTION ECOLOGICAL PRIMARY PRODUCERS SECONDARY PRODUCERS 1° consumer2° consumer3° consumer HerbivoresCarnivores 2050/100,000 = /250 = 80 20/20 = 100 X 100 = % ( )/2050 = 51.2(150+20)/200 = 85( )/20 = /1050 = /170 = /18 = /100,000 = 0.220/250 = 80.5/20 = 2.5