The flux of energy and matter

Report
Energy and nutrient cycles
Raymond L. Lindeman
(1915-1942)
Marine
Tropical and
subtropical oceans
Temperate oceans
Polar oceans
Coastal shelfs
Coral reefs
Total
Lindeman’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).
NPP Terrestrial
NPP
13 Tropical rainforests
16.3 Broadleaf deciduous forests
6.4 Boreal evergreen forests
10.7 Mixed forsts
1.2 Savannahs
Grasslands
Shrub steppes
Tundras
Deserts
Plantations
48.3 Total
17.8
1.5
3.1
3.1
18.8
2.4
1
0.8
0.5
8
56.4
Net primary productivity (unit= 1015 kg×year-1)
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
Biome
Tropical rainforests
in gross primary productivity Broadleaf deciduous forests
Boreal evergreen forests
(unit= 1012 kg C×year-1) Mixed forsts
Modified from Geider et al. 2001, Gl Change Biol, 7
Variability
Heinz Ellenberg
(1913-1997)
Modified from Falge et al. 2002, Agr Forest Meteo, 13
GPP
3-3.5
1.1-1.5
0.7-1.7
0.9-1.9
The earth energy budget
Sun
100% = 1.7 1017 Watt
radiation
42
reflected
radiation
0.002
100
Heat energy
23
23
34
1
0.018
Atmosperic
water
Plants
Fossilized
energy
Only 0.023% (4 1013 Watt)
of the incoming radiation
of the sun is converted in
organic matter
Wind
0.023
Fungi
0.006
Bacteria
Tidal
energy
Animals
0.006
Humans
Geothermal
energy
The global oxygen cycles
OH
O
O2
Atmosphere
H2O
UV
H2O
O
O2
H
O2
O2
O3
Oxydation
O2+2CO→
2CO2
Photosynthesis
Respiration
Biosphere
Water cycle
Pedosphere
Hydrosphere
O2
Vulcanism
CO
O2+4FeO→
2Fe2O3
Bleaching
Ground water
Litosphere
The major oxygen producers are marine algae and terrestrial green plants.
The major processes that reduce atmospheric oxygen are CO and iron oxidation.
Local and global flux of matter in the biosphere
Global cycles of main
elements:
C, N, O, H
Local cycles of P and of trace elements:
K, Ca, Mg, Cu, Zn, B, Cl, Mo, Mn, Fe
Atmosphere
Bacteria
Plants
Plants
Soil
Consumers
Soil
Consumers
Litter
Decomposers
Litter
Decomposers
Amount of radiation that
reaches the biosphere
83%
The energy budget of the biosphere
100%
40%
3%
57%
17%
Net production P is calculated from
 = 3.7
3.7: average carbon fixation rate of chlorophyll
R: relative photosynthesis rate,
k: extinction coefficient × m-1 (1 in terrestrial
systems)
C: amount of chlorophyll × m-3
1-3%
57%
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.
P: Production at trophic level n
 = 100 ×

−1
Consumption efficiency
I: Consumption at trophic level n
 = 100 ×

−1
Transfer efficiency
 = 100 ×
P: Assimilation at trophic level n


Assimilation efficiency
 = 100 ×


Production efficiency
The global cycle of potentially biologically active carbon
Plant respiration
50
Microbial respiration
60
Atmosphere
720 × 1012 kg
Human emissions 7.7
Land use 1.5
93
Photosynthesis
123
90.2
Plant and fungal
biomass 600
Soil carbon 2,300
Ocean surface
700
Deposition 13
Deep ocean
2.8
1,000
Reactive sediments >6,000
Fossil carbon >5,000
Th annual increase of athmospheric carbon from fossil fuel burning
Atmospheric
Net emissions from
= Emissions from fossil fuels +
increase
changes in land use
4.1 ± 0.04
=
7.7 ± 0.4
+
1.5 ± 0.7
-
Oceanic uptake
-
2.3 ± 0.4
-
Average Annual Carbon Fluxes for the period 2000-2008 (Modified from LeQuéré et al., 2009)
Residual
carbon
sink
2.8 ± 0.9
The Nitrogen cycles
The marine nitrogen cycle
The soil nitrogen cycle
Atmosphere
Rain
N2
Atmosphere
Rain
N2
Euphotic
zone
Phytoplankton
Nitrogen
fixation
Denitrification
Marine food web
N
recycling
N2
NH4OH
NO3-
NH4OH
NH4OH
Nitrification
Dark
zone
Clostridium;
Pseudomonas
Decomposer
N
recycling
NO3-
Denitrification
N2
anerobic Bacteria,
Fungi
NO3-
symbiontic
Rhizobium
Ammonification
NH4OH
free living Azotobacter
Nitrification
Nitrosomonas
Nitrobacter
NO2-
Soil
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
Arthur George Tansley
(1871-1955)
ecosystem = biocoenosis + habitat
A community is a group of species that potentially interact
An assembly is any association of species within a given area
Examples of ecosystems:
Lakes
Mangroves
Coral reef
Forests
Grasslands
Tundras
Shrublands
Geothermal vents Deserts
Habitats that are not ecosystems in a strict sens:
Rivers
Oceans
Agricultures
Ecosystems are
characterized by a flux of
energy and a circulation of
inorganic matter.
There is still a dispute
whether ‚ecosystems’ are
‚systems’ in a strict sense.
O2, CO2, H20
Light
A simple scheme of an ecosystem
O2, CO2, H20
Consumers
Producers
Herbivores
Plants
Carnivores
Algae
Herbivores
Parasites
Dead organic matter
Microvores
Consumers
Reducers
Saprovores
Mineralisers
Minerals
Mineral sink
Regulated or not regulated?
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

=  − 


=  − 


=  − 

Simple ecological models predict ecosystems
to be self-regulated entities.
Two types of regulation
Self controlled system
Statistical averaging
  
+
+
= 
  
The flux of matter through
the ecosystem is predicted
to be a steady state
process
Control loop
Early ecological theory saw ecosystems
as self regulated entities.
Examples:
Predator – prey relationships
Degree of herbivory
Energy flux
Population densities
Productivity
Biodiversity
The variance – mean relationship of most
populations follows Taylors power law
 2 () ∝  
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
Statistical averaging as a stabilizing force
The Portfolio effect
 ∝


Number of variables
Stability
Variance
The average of many random variables has a lower variance than each single variable:
statistical averaging
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
The soil
system
Microfauna
Earthworms
Darwin on
earthworms
From Begon,
Townsend,
Harper, 006.
Ecology,
Blackwell
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
Eukaryote
Eukaryote
Eukaryote
Eukaryote
Eukaryote
Eukaryote
Eukaryote
Eukaryote
Chromalveolata
Chromalveolata
Chromalveolata
Amoebozoa
Plantae
Animalia
Animalia
Animalia
Animalia
Chlorophyta
Nematoda
Rotifer
Tardigrada
Arthropoda
Collembola
Eukaryote
Animalia
Arthropoda
Eukaryote
Eukaryote
Eukaryote
Eukaryote
Eukaryote
Eukaryote
Animalia
Animalia
Animalia
Animalia
Animalia
Animalia
Eukaryote
Eukaryote
Diatomea
Xanthophyceae
Ciliophora
Amoeba
Primary producers
Primary producers
Microvore
Microvore
Primary producers
Bacteriovores
Saprovores
Bacteriovores
Fungivores
Arachnida
Acarina
Saprovores, Carnivores
Arthropoda
Arthropoda
Arthropoda
Arthropoda
Arthropoda
Arthropoda
Arachnida
Insecta
Insecta
Insecta
Chilopoda
Diplopoda
Pseudoscorpionida
Coleoptera
Diptera
Hymenoptera
Carnivores
Carnivores
Saprovores
Carnivores
Carnivores
Carnivores
Animalia
Annelida
Clitellata
Enchytraeidae, Lumbricidae
Saprovores
Animalia
Mollusca
Gasteropoda
Herbivores
The animals of each compartment in a German beech forest
Guild
Group
Main taxa
Microfauna
Microvores Testacea
Microvores Nematoda
Mesofauna (saprophagous and
microphytophagous)
Saprovore Enchytraeidae
Saprovore Cryptostigmata
Microvores Collembola
Mesofauna (saprophagous and
microphytophagous)
Gamasina
Microvores Gamasina
Macrofauna (saprophagous)
Saprovores
Saprovores
Saprovores
Saprovores
Gastropoda
Lumbricidae
Diptera larvae
Isopoda
Carnivores
Carnivores
Carnivores
Carnivores
Araneida
Chilopoda
Carabidae
Staphylinidae
Macrofauna (zoophagous)
Parasitoids
Carnivores Hymenoptera
Macrofauna (phytophagous)
Herbivores Cecidomyiinae
Herbivores Rhynchota
Herbivores Lepidoptera
Vertebrata
Sum
No. of species
Individuals x m-2
Biomass (mgDW x m-2)
150
65
65
85000000
84000000
640000
2000
343
150
160
92000
960
36
60
50
22000
26000
38000
600
180
150
67
2600
45
67
300
30
11
250
5
250
100
10
24
85
550
550
> 250
20
20
150
30
1700
2600
3500
120
200
2800
200
500
170
190
5
100
400
400
1500
600
500
130
< 0.01
85000000
45
12000
400
11000
160
40
650
140
265
140
80
70
70
200
80
20
70
< 1000
16000
The function of the edaphon
Biomass
Macrofauna
Mesofauna
Microfauna
Tropical
desert
Tropical
forest
Grassland
Temperate
forest
Boreal
forest
Tundra
Polar desert
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
Decomposition of organic
matter W is an exponential
process in time t with
decomposition constant k
 = 0  −
Decomposition rate
increases nearly
linearly with nitrogen
and phosphorus
content of dead plant
material

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