Raymond L. Lindeman (1915-1942) Energy and nutrient cycles Lindeman’s theory of energetic ecologic...
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Transcript of Raymond L. Lindeman (1915-1942) Energy and nutrient cycles Lindeman’s theory of energetic ecologic...
Raymond L. Lindeman (1915-1942)
Energy and nutrient cyclesLindeman’s theory of energetic ecologic was th
main trigger to initiate the international biological program (IBP) that run from 1964 to 1974
(European projects ended in the 80s). Heinz Ellenberg (1913-1997)
Marine NPP Terrestrial NPPTropical and subtropical oceans 13Tropical rainforests 17.8Temperate oceans 16.3Broadleaf deciduous forests 1.5Polar oceans 6.4Boreal evergreen forests 3.1Coastal shelfs 10.7Mixed forsts 3.1Coral reefs 1.2Savannahs 18.8
Grasslands 2.4Shrub steppes 1Tundras 0.8Deserts 0.5Plantations 8
Total 48.3Total 56.4
Some definitions:Biomass is the mass of organisms per unit of area. It is the standing crop.Units: J×m-2 or kg×m-2
The primary productivity is the amount of energy produced per unit area by plants.Net primary productivity is the difference between gross primary productivity (GPP) and autothrophic plant respiration (AR). Gross primary productivity (GPP )is the total fixation of energy by photosynthesis per unit of area.NPP=GPP-AR; Units: J×m-2×year-1 or kg C×m-2×year-1
Net primary productivity (unit= 1015 kg×year-1)Modified from Geider et al. 2001, Gl Change Biol, 7 Biome GPP
Tropical rainforests 3-3.5Broadleaf deciduous forests 1.1-1.5Boreal evergreen forests 0.7-1.7Mixed forsts 0.9-1.9
Variability in gross primary productivity (unit= 1012 kg C×year-1)
Modified from Falge et al. 2002, Agr Forest Meteo, 13
Sun radiation
reflected radiation Heat energy
Tidal energy
Geothermal energy
Fossilized energy
Plants AnimalsBacteria Humans
Wind
Atmosperic water
100
34 23
42
1
0.023
0.018
0.002
0.006
0.006
23
Only 0.023% (4 1013 Watt) of the incoming radiation of the sun is converted in organic matter
100% = 1.7 1017 Watt
The earth energy budget
Fungi
Atmosphere
Biosphere
Pedosphere
Litosphere
Ground waterHydrosphereO2
O2
O2O2
O3
O
H2OH2OH
OHO
O2
UV
CO
O2+2CO→2CO2
O2+4FeO→2Fe2O3Bleaching
Vulcanism
Water cycle
The global oxygen cycles
Photo-synthesisRespiration
The major oxygen producers are marine algae and terrestrial green plants.The major processes that reduce atmospheric oxygen are CO and iron oxidation.
Oxydation
Local and global flux of matter in the biosphere
Global cycles of main elements:C, N, O, H
Consumers
Plants
LitterDecom-posers
Soil
Local cycles of P and of trace elements:K, Ca, Mg, Cu, Zn, B, Cl, Mo, Mn, Fe
Consumers
Plants
LitterDecom-posers
Soil
BacteriaAtmos-phere
100%
The energy budget of the biosphere
17%
83%
40%
1-3%
57%
3% 57%
Net production P is calculated from
3.7: average carbon fixation rate of chlorophyllR: relative photosynthesis rate,k: extinction coefficient × m-1 (1 in terrestrial systems)C: amount of chlorophyll × m-3
Amount of radiation that reaches the biosphere
Global average energy budget
On average about 10% of energy is transmitted from one trophic levels to
the next. The marine potential productivity depends on latitude and season.
NPP increases with standing crop Modified from Whittaker, 1975, Ecol. Monogr, 23.
Photosynthetic effeciency differs betwen habitat types Modified from Webb et al., 1983, Ecology, 64.
Photosynthetic effciciency in the Argentine pampas is limited by water and temperature.
Modified from Jobbagy et al. 2002, Ecology, 83
The rate of energy transferred to the next trophic level depends on habitat type and NPP.Modified from Cebrian 1999, Am Nat, 154.
𝐶𝐸=100×𝐼𝑛𝑃𝑛−1
𝐴𝑆=100×𝐴𝑛
𝐼𝑛𝑃𝐸=100×
𝑃𝑛
𝐴𝑛
𝑇𝐸=100×𝑃𝑛
𝑃𝑛−1
Consumption efficiency Transfer efficiency Assimilation efficiency Production efficiency
P: Production at trophic level n I: Consumption at trophic level n P: Assimilation at trophic level n
The global cycle of potentially biologically active carbon
Reactive sediments >6,000Fossil carbon >5,000
Atmosphere 720 × 1012 kg
Ocean surface 700
93 90.2
Deep ocean 1,0002.8
Soil carbon 2,300
Plant and fungal biomass 600
Photosynthesis123
Plant respiration50
Microbial respiration60
Human emissions 7.7Land use 1.5
Deposition 13
Atmospheric increase = Emissions from fossil fuels + Net emissions from
changes in land use - Oceanic uptake -Residual carbon
sink
4.1 ± 0.04 = 7.7 ± 0.4 + 1.5 ± 0.7 - 2.3 ± 0.4 - 2.8 ± 0.9
Average Annual Carbon Fluxes for the period 2000-2008 (Modified from LeQuéré et al., 2009)
Th annual increase of athmospheric carbon from fossil fuel burning
The Nitrogen cycles
RainN2
Nitrogen fixation
Phytoplankton
Marine food web
NH4OH
NH4OH
NitrificationNO3-
NO3-
Denitrification
N2
N recycling
Euphotic zone
Dark zone
Atmosphere
N recycling
The marine nitrogen cycle The soil nitrogen cycle
AtmosphereRain
N2
Soil
symbiontic Rhizobium
Decomposeranerobic Bacteria,
Fungi
NH4OHfree living Azotobacter
NH4OH
NitrificationNitrosomonas
NO2-
NO3-
Denitri-fication
Ammoni-fication Nitro-
bacter
Clostri-dium;Pseudo-monas
N2
Leaching into ocean
water
The succession of nutrient uptake can be traced by radioactive markers
32P uptake in freshwater systems
Nutrient uptake by microorganisms takes a few hours. Plants and algae need up to a day and animals a few days for maximum uptake.
The local flux of energy and matter
An ecosystem is a spatially restricted community of living and organisms (plants, animals, and microbes) that interact with
the abiotic components of their environment
ecosystem = biocoenosis + habitat Arthur George Tansley (1871-1955)
Examples of ecosystems:
Lakes Forests GrasslandsMangroves Tundras ShrublandsCoral reef Geothermal vents Deserts
Habitats that are not ecosystems in a strict sens:
Rivers Oceans Agricultures
A community is a group of species that potentially interactAn assembly is any association of species within a given area
There is still a dispute whether ‚ecosystems’ are ‚systems’ in a strict sense.
Ecosystems are characterized by a flux of energy and a circulation of inorganic matter.
Herbivores
Carnivores
Parasites
Saprovores
Mineralisers
Consumers
Reducers
Plants
Algae
Producers
Dead organic matter
Microvores
Consumers
Herbivores
Minerals
O2, CO2, H20 Light O2, CO2, H20
Mineral sink
A simple scheme of an ecosystem
Regulated or not regulated?
𝑑𝐷𝑑𝑡
=𝑐𝐾−𝑎𝑃𝑑𝐾𝑑𝑡
=𝑏𝑃𝐾 −𝑐𝐾𝑑𝑃𝑑𝑡
=𝑎𝑃−𝑏𝑃𝐾𝑑𝐷𝑑𝑡
+𝑑𝑃𝑑𝑡
+𝑑𝐾𝑑𝑡
=𝑐𝑜𝑛𝑠𝑡
Modelling ecosystem processes
D, P, and K are the amounts of a resource at the levels of reducers (D), producers (P) and consumers (K), respectively. Then it holds
The flux of matter through the ecosystem is predicted
to be a steady state process
Simple ecological models predict ecosystems to be self-regulated entities.
Two types of regulation
Self controlled systemStatistical averaging
Control loop
Early ecological theory saw ecosystems as self regulated entities.Examples: Predator – prey relationshipsDegree of herbivoryEnergy fluxPopulation densitiesProductivityBiodiversity
The variance – mean relationship of most populations follows Taylors power law
The majority of species has 1.5 < z < 2.5
Z = <<2 is required for population regulation
Most populations, in particular invertebrate populations are not regulated!
They are not in equilibrium
𝜎 2(𝑁 )∝𝑁 𝑧
Statistical averaging as a stabilizing force
The Portfolio effect
The average of many random variables has a lower variance than each single variable: statistical averaging
Number of variables
Varia
nce Stability𝝈𝟐∝
𝟏√𝑵
Aggregate ecological variables (biomass, species richness, productivity, populations) become more stable with increasing number of independent variables.
For instance, total biomass and ecosystem productivity are more stable in species rich communities.
The soil system as an example of an ecological system
From Begon, Townsend, Harper, 006. Ecology, Blackwell
Earthworms
Microfauna
Darwin on earthworms
The soil system
Soil organisms: Edaphon
Domain Kingdom Phylum Class/Order Examples Ecological function
Prokaryote Bacteria Proteobacteria Nitrosomonas, Nitrobacter, Rhizobium, Azotobacter N cycle
Prokaryote Bacteria Firmicutes Clostridium N cycle
Eukaryote Fungi Ascomycota Penicillium, Aspergillus, Fusarium, Trichoderma Saprovores
Eukaryote Chromalveolata Diatomea Primary producersEukaryote Chromalveolata Xanthophyceae Primary producersEukaryote Chromalveolata Ciliophora MicrovoreEukaryote Amoebozoa Amoeba MicrovoreEukaryote Plantae Chlorophyta Primary producersEukaryote Animalia Nematoda BacteriovoresEukaryote Animalia Rotifer SaprovoresEukaryote Animalia Tardigrada BacteriovoresEukaryote Animalia Arthropoda Collembola Fungivores
Eukaryote Animalia Arthropoda Arachnida Acarina Saprovores, Carnivores
Eukaryote Animalia Arthropoda Arachnida Pseudoscorpionida CarnivoresEukaryote Animalia Arthropoda Insecta Coleoptera CarnivoresEukaryote Animalia Arthropoda Insecta Diptera SaprovoresEukaryote Animalia Arthropoda Insecta Hymenoptera CarnivoresEukaryote Animalia Arthropoda Chilopoda CarnivoresEukaryote Animalia Arthropoda Diplopoda Carnivores
Eukaryote Animalia Annelida Clitellata Enchytraeidae, Lumbricidae Saprovores
Eukaryote Animalia Mollusca Gasteropoda Herbivores
The animals of each compartment in a German beech forest
Guild Group Main taxa No. of species Individuals x m-2 Biomass (mgDW x m-2)
Microfauna 150 85000000 2000 Microvores Testacea 65 84000000 343 Microvores Nematoda 65 640000 150Mesofauna (saprophagous and microphytophagous) 160 92000 960
Saprovore Enchytraeidae 36 22000 600 Saprovore Cryptostigmata 60 26000 180 Microvores Collembola 50 38000 150Mesofauna (saprophagous and microphytophagous) Gamasina 67 2600 45
Microvores Gamasina 67 2600 45Macrofauna (saprophagous) 300 3500 12000 Saprovores Gastropoda 30 120 400 Saprovores Lumbricidae 11 200 11000 Saprovores Diptera larvae 250 2800 160 Saprovores Isopoda 5 200 40Macrofauna (zoophagous) 250 500 650 Carnivores Araneida 100 170 140 Carnivores Chilopoda 10 190 265 Carnivores Carabidae 24 5 140 Carnivores Staphylinidae 85 100 80Parasitoids 550 400 70 Carnivores Hymenoptera 550 400 70Macrofauna (phytophagous) > 250 1500 200 Herbivores Cecidomyiinae 20 600 80 Herbivores Rhynchota 20 500 20 Herbivores Lepidoptera 150 130 70Vertebrata 30 < 0.01 < 1000 Sum 1700 85000000 16000
The function of the edaphon
Tropical desert
Tropical forest
Grassland Temperate forest
Boreal forest
Tundra Polar desert
Biom
ass
Macrofauna
Mesofauna
Microfauna
Litter breakdown
Soil organic matter accumulation
Decomposers are bacteria and fungi that
reduce organic material
Detritivores are animal or protist
consumers of dead organic matter
Predators feed on soil animals or
protists
Microvores are animal or protist consumers of bacteria and fungi
Decomposers and detritivores
𝑊 𝑡=𝑊 0𝑒−𝑘𝑡
Decomposition of organic matter W is an exponential
process in time t with decomposition constant k
Decomposition rate increases nearly
linearly with nitrogen and phosphorus
content of dead plant material