The stability of ecosystems and their resistance to contamination Lecture № 2,3 The stability of ecosystems and their resistance to contamination

The concept of ecosystem resilience The stability of natural biological systems (population, or biocoenosis) should understood as the ability for many generations continuously preserve the natural structure and function in a dynamic equilibrium with the environmental changes and the ability to repair itself after structural disturbance  due to external influences

Ecosystem - an open, self-regulating and self-developing system Provided by: resistant relationships between their components (community of organisms and abiotic components); trophic relationships and energy; variety of organisms that perform the same function, but occupy different ecological niches; permanent self-reproduction of populations, the capacity for evolution of species and microevolution of populations Rapid adaptation to  environmental changes

The biosphere natural unit principles Сirculation of substances Species diversity Biospheric stability The pyramid of energy Stability of populations Adaptability of species

Features of natural and man-made ecosystems Homeostasis - population or ecosystem ability to maintain stability in a changing environment Under natural conditions: variability of ecosystem continuing violation of equilibria fluctuations in population size due to internal and external influences, interactions of different species The stability of ecosystems: individual physical, chemical and biological balance stability of mass and energy exchange process, stability of matter and energy cycles

The stability of ecosystems ability to return to its original state after the system was derived from an equilibrium state Self Regulating Systems Stable mobile equilibrium: old relationships are renewed more rapidly, the duration of the resumption depends on the violations scale and on the specific system properties Unstable equilibrium: series of changes begin to develop rapidly and irreversibly even for small violations of existing relationships in natural systems.

Types of stability resistant stability - the ability to remain in the steady state under the load elastic resistance - the ability to recover quickly Three degrees of ecosystems’ deviation from equilibrium under the  external factors: stress - the composition of biological communities is practically unchanged, the structure is changed significantly, there is a redistribution of species as a function of the dominant degree; resistant state - is sharply reduced species diversity and the changing composition of the community; resistant to the external factor population develop; this condition is characterized by the biomass  stability of the total organisms community; repression - the complete suppression of the organisms’ development

Resistant and resilient ecosystem sustainability ecosystem disturbance range of normal operation overall ecosystem sustainability Ecosystem functioning measure resistance measure of elasticity

Biogeochemical Cycles Circulation of gases in which the atmosphere is the main reservoir of elements and compounds: C, N and H2O. Sedimentary cycle of elements (sedimentary cycle) that is the part of the sedimentary rocks: P, S (elements circulate through erosion, sedimentation, mountain building and volcanic activity, biological transfer) cycling of matter that make up the pollution: Hg, Pb, (90)Sr - analogue Ca, (137)Cs - similar to K, pesticides

Carbon Cycle

The mechanism of carbon transformation under aerobic conditions: all substances of biological origin is completely or partly oxidized (to CO2 and H2O) under anaerobic conditions: natural biopolymers (proteins, nucleic acids, carbohydrates, lipids, waxes, compounds with aromatic structures, vitamins, toxins can be partially transformed into reduced carbon compounds (oil, coal) or degraded to carbon dioxide and methane

Biogeochemical cycle of toxicants destructive processes decomposition and mineralization of biochemical synthesis products, transformation; mineralization of chemical synthesis products

Механизмы биологического окисления Mechanisms of biological oxidation Heterotrophic oxidation (a carbon source - ready organic matter) microorganisms CO2 +H2O + non-oxidizing organic solutes O2 + N + P Microorganisms (biomass) + O2 biologically indestructible part of the cell substance CO2 +H2O +N + P + Autotrophic oxidation (nitrification) (a carbon source - inorganic carbon) 55 NH4+ + 5 CO2 + 76 O2 C5H7NO2 + 54 NO2- + 52 H2O + 109 H+ C5H7NO2 + 400 NO3- +H+ 400 NO2- + 5 CO2 + NH4+ +195 O2 +2 H2O C5H7NO2 - composition of the resulting microbial cells

Mechanism of Wastewater and Sludge Methane Fermentation Basic organic compound - carbohydrates, proteins, fats. а Stage I - Hydrolysis Simple soluble organic compounds Stage II - Acid production а Acetates, butyrates, alcohols, propionates а а b b Stage III - Acetic acid formation Н2, СО2 c СН3СООН d f СН4, СО2 Stage IV – Methane formation Participating groups of bacteria: a - enzymatic acidogenes, b- acetogenes forming H2, c- acetogenes using H2 d- methanogenes, reducing CO2, f - methanogenes using acetate

The Chemistry of Methane Fermentation I Stage (hydrolysis) Stage II (acid production): Stage III (acetogenic): Stage IV (methanogens): The bacteria of the “a" Simple soluble organic matter PROTEINS FATS CARBOHYDRATES СН3-СН2-СН2-СООН; СН3-СН2-СООН butyric acid, propionic acid, alcohols; amino acids Simple soluble organic matter Н2; СО2 CH3 CH2 COOH + 2H2 O  CH3COOH + CO2 + 3H2 CH3 CH2 CH2COOH + 2H2 O  2CH3COOH + 2H2 The bacteria of the "b" 4H2 + 2CO2  CH3 COOH + 2H2 O Bacteria of the “c" CO2 + 4H2  CH4 + 2H2O; CH3OH + H2  CH4 +H2O; HCOOH +3H2  CH4 + H2O 28% of the methane produced. CH3 COOH  CH4 + CO2 72% of the methane produced Bacteria of the “f" Bacteria of the “d"

Nitrogen cycle the nitrogen cycle takes place in the atmosphere, lithosphere and hydrosphere. Majority (in the form of N2) is concentrated in the atmosphere (75.6%)   Part is dissolved in the sea water;   In the form of dissolved ammonium, nitrite and nitrate ions - nitrogen presents in the organic matter and in the soil

Involvement of nitrogen in the natural cycle Abiotic processes for capturing - lightning, damaging of UV rays, burning, (no more than 10-20% of fixed nitrogen); Biological transformation involving inorganic nitrogen metabolism - nitrogen fixation, assimilation, ammonification, nitrification, denitrification - a vicious cycle that has no any effect on the atmosphere

Biological nitrogen cycle

Sulfur cycle composed of various inorganic and organic compounds;   in the form of deposits of sulfide minerals - breakdown products of parent rocks; on the surface as brimstone; in the air as SO2, H2S, sulphate aerosols

Deposition of sulfur sulfur cycle, as well as all the biogeochemical cycles is not closed completely, including reducing and oxidizing processes accumulation of excess weight of sulfur in the hydrosphere, and atmosphere pedosfere doesn’t happen excess of sulfur is removed in the form of iron sulfides (hydrotroilite, pyrite, marcasite), at the bottom of the oceans and seas, as well as soluble calcium sulfate, and magnesium)

Sulfur in transit environments at the top, aerobic water column: biogenic hydrogen sulfide forming due the reduction processes, is oxidized by chemical or biological ways; in the atmosphere: hydrogen sulfide quickly (within 2 days) is oxidized to SO2, further to SO3 (under the influence of oxygen on the dust particles of metal oxides (catalysts) or particles of moisture under the influence of sunlight, with the further formation of sulfuric acid); transit: highly soluble sulfates and acid washed out of the atmosphere and migrate into the aquatic environment; in water under the action of sulfate reducing bacteria pass into the soluble sulfides, which are accumulated in the sediments

Sulfur conversion in soils sulfur undergoes chemical and biochemical changes going from inorganic to the organic form and back; Part of the sulfur is assimilated by plants and microorganisms in the form of sulfates; hydrogen sulfide is formed under sulfate reduction processes and the as the result of decaying and decomposing processes

Microbial sulfur oxidation elementary sulfur, sulfates in nature Aerobic Zone (aerobic chemolithotrophic sulfur bacteria, thione, thermoacidophilic bacteria) Anaerobic Zone (photosynthetic bacteria) Thione bacteria and sulfur bacteria are permanent residents of waste water containing can reduce content of sulfur compounds (mercaptans, dimethyl sulfide, etc.) elementary sulfur, sulfates

Phosphorus Cycle Features Phosphorus Sources: rocks and sediments formed in the distant geological epochs. In the crust: in the form of minerals and chemical compounds – insoluble phosphates (0.1%) Features: not active, slow-moving and difficult to reach for biota. In living organisms: in the form of orthophosphates or metaphosphate

Features of Phosphorus Distribution in Nature The global phosphorus cycle is the most closed, occurs only in the lithosphere and hydrosphere; There is a one-way flow of phosphorus from the land into the water and into the bottom sediments (as a result of weathering of rocks); Phosphate from an aqueous medium is output in the form of insoluble iron phosphate. Negligible moving through the atmosphere in the form of aerosol; There is less phosphorus than nitrogen in almost all the natural biogeochemical systems; it does limit the weight of living matter

Phosphorus Biogeochemical Cycle

Phosphorus Biogeochemical Cycle Insoluble phosphates Acidic medium As a result of microorganisms acidic metabolic products:   nitric acid (nitrifying bacteria), sulfuric acid (thiobacteria) and organic acids (lactic, glycolic, oxalic, citric, 2-ketoglutaric acids) Decomposition  of residues, microorganisms involved in mineralization of organic phosphorus compounds (nucleic acids, inositol phosphates, phospholipids Soluble phosphates in organic compounds

Self-purification of natural environments (water, soil) Abiotic processes: physical, physico-chemical, chemical Biotic processes biological biochemical Biotic processes - due to the activity of organisms of natural habitats through inclusion of a contaminant in the food chain, its oxidation (energy metabolism), or use in a constructive exchange Abiotic processes - transport of pollutants (air, water reservoirs) or their dilution (mixture of dirty water flow with clean air)

Abiotic processes the transfer and incorporation of substances in the water mass in the precipitation and sedimentation of inorganic insoluble organic substances; emission of volatile substances to the atmosphere; equilibrium with the atmosphere of the reaction gases (O2 consumption or loss of CO2, N2, etc.); Photochemical reactions in the troposphere: characteristic of organic molecules, organochlorines (intramolecular reaction in the excited state) Physico-chemical processes in the water and on the surface of suspended particles and precipitation: absorption and adsorption, dissolution and precipitation, emulsification and flotation, etc .; chemical processes in the water column: acid-base, redox, complexation, hydrolysis; chemical precipitation processes: conversion of precipitation in a reduced state of oxidation, and vice versa;

Abiotic (biological) processes - metabolism of pollutants exampls biochemical processes: the inclusion of poliutants into aquatic biota; decomposition of digestible organic and assimilated inorganic compounds by microorganisms ; biological processes: removal of colloids and small zooplankton suspended solids; filtration and sedimentation of impurities by hydrobionts.

Soil’s Microbiocenosis Water conditions (humidity) Inner atmosphere (air in the soil) The content of mineral elements Soil: complex dynamic system Mesofauna: ciliates, flagellates, worms, mollusks, and arthropods Mezoflora: algae, mold, bacteria Soil bacteria

Physiological Functions of Soil Microorganisms putrefactive microorganisms: provide any rotting organic matter and decomposition of urea; nitrifying bacteria: oxidize ammonia to nitrous acid to form nitrites; nitrogen-fixing bacteria: absorb nitrogen from the air, making nitrogen available to plants (providing admission to 100 million tons of nitrogen, while the industry produces about 30 million tons of nitrogen fertilizers); fermentation bacteria: form methane; bacteria involved in the elements cycles: sulfur, iron, phosphorus and other.

Soil Bacteria Escherichia coli  Pseudomonas fluorescens Clostridium

Microbiocenosis functions (Bacterial cenoses) microorganisms-destructors: perform the destruction of the organic substrate into forms of large molecular insoluble compounds (mineralization); hydrolytic microorganisms: transfer large molecular insoluble compounds into soluble low molecular weight compounds and use them for food; Microorganisms of the scattering: use part of the resulting low molecular weight compounds.

Microbiocenosis of water reservoirs in the upper layers of the water: inflow of exogenous organic residues and substances; the synthesis of organic substances by algae and cyanobacteria;  in the lower (colder) reservoir layers: the accumulation of the organic residues; decomposition; fermentation with hydrogen, methane, hydrogen sulfide and carbon dioxide emission. Fermentation Products - substrate for the denitrifying bacteria accompanied with accumulation of nitrites in the water. Cyanobacteria reproduction as a result of human activity: allocation of toxins and eutrophication of water bodies.

Air Microflora Features In the air the microorganisms proliferate poorly due to the lack of moisture and lack of essential nutrients. The source of bacterial contamination of the atmosphere - dust and water droplets of different origin. Atmospheric composition of microflora is determined by: degree of contamination with mineral and organic aerosols, temperature humidity speed of movement of air masses, microorganisms composition in the soil of the region (chromogenic cocci, bacillus, spore-forming bacillus, fungi) - a constant component.

Technologies of environment protection and restoration Elucidation of mechanisms of natural environments’ self-purification and their directional regulation Development of the environmental regulation of pollutants system The development of new treatment technologies Internal or passive remediation - the use of self-purification processes in natural conditions without artificial acceleration of the process Using of organic waste biodegradation technologies