Russian Academy of Sciences A.M. Obukhov Institute of Atmospheric Physics Laboratory of Mathematical Ecology Nikolay N. Zavalishin Reaction of the biotic cycle in southern taiga forest and peatland ecosystems of European part of Russia to the climate change and human perturbations e-mail: nickolos@ifaran.ru Supported by the RFBR project 10-05-00265a and the Program “Physical and chemical processes in atmosphere and cryosphere determining climate and environmental change”
Peatland and forest ecosystems of the southern taiga in European part of Russia Mires and forests of southern taiga take an important part in regulating biogeochemical cycles of carbon, nitrogen, water and mineral elements both at regional and at the global levels. Carrying out an active matter exchange with the environment they can be sources or stocks for green-house gases under the climate change and human economic and resource-mining activities. Due to structural complexity and lack of knowledge on functioning mechanisms, mathematical modelling of main ecosystem biogeochemical cycles is necessary for forecasting reactions and dynamic behavior of those ecosystems to extern al perturbations. by vegetation cover Elements of bog ecosystems classification by nutrient-water regime forest forest-fen fen Oligotrophic Mesotrophic Eutrophic Nutrient-water regime is carried out Formed under high humidity Formed under the mixed type of by underground water or rivers with conditions and a lack of nutrient-water regime by high content of mineral elements. nutrient load that is realized atmospheric precipitation, input Vegetation cover has a high only by atmospheric from adjacent ecosystems, as well as biodiversity, species richness and precipitation. A typical underground water. Vegetation can structural complexity. feature is small number of include both oligotrophic and plant species and a cover of eutrophic species, and has higher sphagnum mosses. level of biodiversity.
Biogeochemical cycles in different types of peatland ecosystems ? Local low-parametric dynamic model of coupled carbon-nitrogen cycles with climatic parameterization and steady Oligotrophic, mesotrophic, eutrophic peatland ecosystems in the states corresponding to the bog southern taiga, European part of Russia (Novgorod region): carbon, nitrogen and mineral element biotic cycles (Bazilevich and Tishkov, ecosystems classification 1982, 1986; Alexandrov et al., 1994) Photos are from (Bazilevich and Titlyanova, 2008)
Biogeochemical cycles in adjacent forest ecosystems ? A steady state for the local low-parametric dynamic model of coupled carbon- nitrogen cycles in bog ecosystems with climatic parameterizations Spruce-bilberry ecosystem in the Main problems (how to…?): southern taiga, European part of 1) Aggregation of a multi-compartment scheme; Russia (Novgorod region): carbon, 2) Low-parametric dynamic model design from some nitrogen and mineral element biotic static balanced or disbalanced diagrams. cycles (Bazilevich et al., 1986)
Aggregation principles and techniques for compartment schemes G D+D’ Ph+Z Carbon flows in ecosystems: photosynthesis, respiration, Pr V+L+{ Slh } Mo+F+ Sph consumption, death, excretion, litterfall fixation in actual growth, Sln input, output, abiotic oxidation R translocation Reservoires : G – green phytomass, Pr – perennial phytomass, R – living roots, D+D’- standing dead phytomass, V+L+{ Slh } – dead roots + litter + organic matter in soil, Ph+Z – phytophages+zoophages, Mo+F+ Sph – microorganisms+fungi+saprophages, Sln – soil reserve of nutrients. Aggregation principles: 1) division of living and dead organic matter; 2) division of above- and underground living organic matter; 3) consumers (Ph+Z) and destructors (Mo+F+ Sph ) are aggregated into separate units independently on where they live.
Aggregated scheme of carbon and nitrogen cycles in ecosystems C = 987.5 q 1 N =0.9 q 1 5 C 1 = 8490 , Reservoires : C 1 , N 1 - carbon and nitrogen N 1 = 26.3 in living organic matter (LOM), C 2 , N 2 – N =0.083 y 1 N =0.41 q 2 C = 598.5 y 1 C =38.49 carbon and nitrogen in consumers and f 12 N = 5.635 f 31 C =0 destructors, C 3 , N 3 – carbon and nitrogen q 2 C 2 = 35.2 , in litter and other dead organic matter N =0.756 f 12 N 2 = 0.1 C = 342.7 f 13 (DOM). N = 6.16 C =296.6 f 13 y 2 C = 621.8 f 32 C q 3 C =363.21 f 23 N =0.7 N =0.13 Intercompartment flows : f 32 f 23 C 3 = 8835 , N 3 = 78.9 , f 12 C , f 12 N – consumption of biomass by C = 114.3 y 3 phytophages, f 13 C , f 13 N – litterfall, f 23 C – N =0.825 q 3 death of consumers and microorganisms, N =1.58 y 3 f 31 N –nitrogen consumption from soil Input and output flows : resource by roots, and translocation, f 32 C – q 1 C – carbon assimilation from atmosphere, destruction of dead organic matter, f 23 N – q 3 C – carbon input from adjacent ecosystems excretion by microorganisms and (abcent in oligotrophic case), q 2 N – fixation of consumers. atmospheric nitrogen by microorganisms, q 3 N – nitrogen input with surface water and precipitation, y 1 C , y 2 C – respiration and Units : storages C - in g/m 2 of dry consumption by phytophages of another weight, flows C in g/m 2 · year of dry ecosystems, y 2 N – denitrification, y 3 C – peat weight; formation, carbon output with streams, abiotic oxidation, y 3 N – peat formation and nitrogen storages N – in gN/m 2 , flows N – in output. gN/m 2 · year.
General problem of a dynamic model design by a given «storage-flow» diagram for a single biogeochemical cycle f k i = 8.5 a set of compartment schemes for time moments t 0 , t 1 ,…, collected from the q k = 0.5 q i = 8 x k =3.5 x i =70 field studies f k i = 15 y i = 3 y k = 0.8 f ik (x i , x k ) ? x 1 = 180 q k ( t ) q i ( t ) x k ( t ) x i ( t ) q 1 = 30 y 1 = 10 f ki ( x k , x i ) y k ( x k ) y i ( x i ) dynamic model for storages in x 1 ( t ) reservoires q 1 ( t ) y 1 ( x 1 ) dx n The main problem: how to make dynamic model i ( ) q y f f = − + − ∑ i i ki ik dt from one flow-balanced diagram? k 1 , k i = ≠ d x q(x) y(x) f(x) = − + Dynamic equations in general form: dt q - vector of input flows from the environment; y - vector of output flows to the environment; f ki - intercompartment flow from i to j
Modified method for a single-cycle dynamic system design Main assumptions (1-5c) for given stationary schemes: 1) q * + f * = y * - at least one of the given diagrams is a dynamic equilibrium; 2) f ki = f ki (x k , x i ); f ik = f ik (x i , x k ) – intercompartment flows depend only on participating storages; 3) q i = const – input flows can have only constant form; 4) y i = m i x i – output flows are linear; 5) intercompartment flow control types : Coefficients of flow functions are ij x a) f ki = donor ; α calculated from the given scheme: i ij x b) f ki = recipient; β y f f f * * * * j x x γ c) f ki = Lotka-Volterra m ki ; ki β ; γ ki ; i ; α ki = ki = ki = i = ij i j * x * x * * * x x x k i i k i 5d) additional control types with saturation : Coefficients of flow functions with K x x saturation are calculated from K x x K x x g ki k i = g ki k i , g ki k i , = = several given schemes or by special ki ( L x )( N x ) ki + + ki L x L x + + ki k ki i calibration procedures ki k ki i ( ), i s ; m − + β − = ∑ α i ik Dynamic compartment model: b i ki i,s = 1 ,…n k i ≠ = s , i s . dx n − ≠ β α n n si is i q i ( g g ) ∑ m x b x x c x = − + + + − ∑ ∑ c is . i i s s i is s γ si − γ i si is = dt is s 1 s 1 = = s 1 = d x / dt B x diag ( ,..., ) C x G ( x ) q x x = + + + 1 n
Modelling a coupled carbon-nitrogen cycle: dynamic mechanisms Carbon and nitrogen interaction is provided by two mechanisms (Logofet, Alexandrov, 1985): 1) N/C decrease in living organic matter results in an increment of total litterfall, due to weakness of plants under nitrogen starvation; 2) N/C increase in dead organic matter results in an increment of the DOM decomposition rate. Mathematical form of coupled N-C flows (Alexandrov, 1994): 1) Litterfall : 2 C N N - carbon flow: , nitrogen flow: f C C C 1 f = α = α 13 13 1 13 13 N 1 2) Decomposition of dead organics: 2 C C C N N - carbon flow: , - nitrogen flow: f N C f 3 C = γ = α 32 32 3 2 31 31 2 N 3 Another intercompartment flow functions : Dynamic equations of the coupled model : C C 1 C 2 ; f 12 dC 3 f 12 C = γ 12 N = γ 12 N N 1 C 2 ; f 23 C = α 23 C C 2 ; i C C ( C C ) q y f f = − + − ∑ i = 1,…,3 i i ki ik dt k 1 , k i = ≠ dN f 23 N = α 23 N N 2 ; f 32 N = γ 32 N N 3 C 2 ; 3 i N N N N ( ) q y f f = − + − ∑ i i ki ik dt Carbon assimilation flux is k 1 , k i = ≠ approximated by a saturation The main purpose : to investigate stability and function: K C bifurcations of steady states as a reaction of the q C 01 1 = 1 L C + carbon cycle to climatic and human 01 1 perturbations.
Recommend
More recommend
