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1 Ecosystem Services, Sustainability and thermodynamic Indicators Saltzau Workshop on Ecosystem Services May 08 By Sven Erik Jørgensen Copenhagen University University Park 2, 2100 Copenhagen Ø

2 How to estimate the sum of all services offered by an ecosystem? Proposal: as the total amount of work energy (work capacity), that the e c o s y s t e m o f f e r s. All activities require energy that can do work. Services by ecosystems mean activities offered to the user of Ecosystems and they could therefore be measured by the work capacity.

3 Sustainability is also determined by amount of work energy, because: 1) Sustainability in the Brundtland s sense: we need to maintain the same level of services to the future generation 2) The amount of energy to be used to break down an ecosystem = the work capacity of the ecosystem

4 What is exergy? Exergy is work capacity - energy that can do work. It can therefore be found as the gradient (= difference in potential)x extensive descriptor, dependent on the energy form, for instance Chemical energy= (µ 1 -µ 2 ) N or Pressure energy= (p 1 -p 2 )(-V) Potential energy= (h 1 -h 2 ) m g Electrical energy= (V 1 -V 2 ) Q

5 We may distinguish between technological exergy and ecoexergy: Technological exergy uses the environment as reference state and is useful to find the first class energy (work) that a power plant can produce Eco-exergy uses as reference state the same ecosystem with the same temperature and pressure but at thermodynamic - chemical equilibrium

6 S, U, V, N1, N2, N3... T, p. µc1,µc2,µc3... Toward thermodynamic equilibrium with the environment S, Uo,V,N1,N2,N3... To,po,µoc1,µoc2,µoc3...

7 System at T, p Displace ment work, not useful Work (exergy) Reference environment at T, p

8 How to find the eco-exergy? i=n i=n Ex = (µ 1 -µ 2 ) C i = RT C i ln C i / C i,o i=0 i=0 n A = c i p i = c i / A i=1 n Ex = A RT pi ln pi / pio + A ln A /Ao = ARTK, i=1 where K is Kullbach s measure of information

9 Free Energy and Eco-exergy Eco-exergy seems to be just a difference in free energy, but it is not the case, because 1) The reference state is different from case to case 2) Eco-exergy is not a state function. Notice the difference in eco-exergy between a living and dead organism is the enormous contribution from information. Eco-exergy can therefore not be differentiated. 3) Eco-exergy is the biomass (containing free energy) times the information.

10 Formulation by exergy: Three possibilities: dex/ dt = dexe/dt + dexi/dt >0 dex/ dt = dexe/dt + dexi/dt <0 dex/ dt = dexe/dt + dexi/dt =0 dexi/dt always negative

11 2. Law of thermodynamics has many different formulations: All processes are irreversible Entropy increases by all real processes We loose energy that can do work to energy (named exergy) that cannot do work because the energy is in form of heat at the temperature of the environment It costs exergy to maintain ecological systems far from equilibrium which is delivered by the solar radiation

12 All ecosystems must be open: Creation of order in a system must be associated with a greater flux of entropy out of the system than into the system. This implies that the system must be open or at least nonisolated.

13 Spark electrodes Gas phase Valve Condenser Boiling water

14 How to find the eco-exergy content of living organism? Eco-exergy = ßI*ci, Where ß is a weighting factor = RT ln ci/cio, considering what the probability is to form the organism at thermodynamic equilibrium, ie. How many amino acids in the right sequence is required to make up the organism, i.e how much information does an organism contain?

15 ß-values found from the genome sizes I Organisms Genome Mb Repeat % ß Human Mouse Tiger fish Mosquito Squirt Fruit fly Yeast Amoeba

16 ß-values found from the genome sizes I Organisms Genome Mb Repeat % ß Human Mouse Worm Mustard weed Rice Virus 1.01 Reptiles 833*) Birds 980*) *) found indirectly

17 We have three growth forms 1) Biomass - physical structure 2) The network 3) The information Notice that they summarize the E.P. Odum s attributes

18 Calculation of Sustainability Total global sustainability cannot be calculated but the increase / decrease of the sustainability / work capacity can be determined; see the book Eco-exergy as Sustainability by S. E. Jørgensen, WIT 2006.

19 Growth forms 2 and 3 are different from growth form 1: They are not following the conservation principles An ecological network has more positive than negative relations Information can be copied at almost no cost The two growth forms are far from their limits

20 It has been examined by use of models and ecological knowledge / E.P. Odums, How the exergy, specific exergy = exergy / biomass, exergy destruction (The Extended 2. Law), power,, entropy production, change with the growth forms I, II and III.

21 We have several ecosystem theories based on Maximum Power Maximum Ascendency Maximum Exergy dissipation Minimum entropy dissipation Maximum exergy storage Ratio indirect / direct effect Specific exergy Specific entropy production

22 Table 2: Relationships between growth forms and goal functions Growth Form I II III Exergy storage up up up Power / through flow up up up Ascendency up up up Exergy dissipation up equal equal Retention time equal up up Entropy up equal equal Exergy / Biomass= specific exergy equal up up entropy /biomass= spec. entropy prod. equal down down Ratio indirect /direct effects equal up up

23 Annual services by ecosystems as work energy: Ecosystem MJ /m2 y Beta-value GJ / ha y Desert Open sea Coastal zones Coral reefs, estuaries ,000 Lakes, rivers ,500 Coniferous forests ,200 Deciduous forests mill. Temperate rainforests mill. Tropical rainforests mill. Tundra Croplands ,000 Grassland ,000 Wetlands ,000

24 What does that mean for the value in EURO or $ / (ha*y)? 1 MJ has the value of 1 EUROcent or 1.4 $-cent 1 GJ has therefore the value of 10 EURO or 14 $.

25 Annual value of services by ecosystems: Ecosystem keuro /ha y $ /ha y according Ratio Costanza et al. Desert 20.7?? Open sea Coastal zones Coral reefs, estuaries Lakes, rivers Coniferous forests Deciduous forests Temperate rainforests 1580?? Tropical rainforests Tundra 72.8?? Croplands Grassland Wetlands

26 We utilize the spectrum of the possible services of the ecosystems differently: A. Coastal zones, lakes, rivers: regulation, water supply, waste treatment, recreation, genetic resources, pollination, nutrient cycles, biological control, food production, refugia, transportation, raw materials, cultural; ratio about 10-20

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28 We utilize the spectrum of the possible services of the ecosystems differently: B. Wetlands: regulation, water supply, waste treatment, recreation, raw material, genetic resources, pollination, nutrient cycles, biological control, refugia, cultural; ratio about 30

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30 We utilize the spectrum of the possible services of the ecosystems differently: C. Open sea, estuaries, coral reef: Only climate and gas regulation, very little waste treatment, much less recreation than A and B, raw material, genetic resources, pollination, nutrient cycles, (minor) biological control, (minor) refugia, raw materials, cultural; ratio about 60-90

31 We utilize the spectrum of the possible services of the ecosystems differently: D. Forests, croplands, grasslands and (deserts): Mainly as raw materials, too little the genetic resources, pollination, nutrient cycles, biological control, (minor) refugia, cultural, recreation; ratio about >750 Notice croplands are only utilized to produce raw materials (mainly food); the ratio is therefore high, 4348

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34 CONCLUSIONS I: The total value of all services offered by the ecosystems may be estimated from the work capacity (eco-exergy) of the ecosystems It is also a measure of the sustainability We can divide the ecosystems in four classes according to how much we have been able to utilize the entire spectrum of services

35 CONCLUSIONS II: We can divide the ecosystems in four classes according to how much we have been able to utilize the entire spectrum of services The sequence of our utilization of the ecosystem services is: lakes and rivers, coastal zones, wetlands, estuaries, open sea ecosystems, grasslands, forests and croplands The sequence is understandable and seems easy to explain

36 THANK YOU FOR YOUR ATTENTION