Biogeochemistry and geochemistry

obligatory courses

The lectures emphasize the particularly important role of biological processes in the global cycle of matter in the biosphere, affecting diverse natural fate of individual elements that make up the varied living environment both on land, in the oceans, and in the atmosphere. The enormous power of human economic activity is pointed out, which may affect the rate of the global cycle of many elements and modify simultaneously (often unconsciously) Earth’s climatic conditions or cause hazards by putting into circulation xenobiotics or substances that cause unpredictable and dangerous effects in the natural environment. The origin of the specific cycles on Earth are analyzed in geological terms and compared to other objects in our Solar System.

PROCESSES AND REACTIONS

L 1. INTRODUCTION. Explanation of the scope of biogeochemistry and justification of Earth’s treatment in the science as a system of complex chemical bonding closely related to the functioning of living organisms. Discussion of the temporal and spatial scales, explanation of thermodynamics and stoichiometry principles used biogeochemical analysis and explanation of their importance. Presentation of examples and model assumptions in which these rules are implemented. By treating of such models in an extremely idealized form, we can come to the controversial and provocative concept of GAIA as a self-regulating super-organism that according to this theory is the Earth. Discussion on the GAIA concept.

L 2. BEGINNINGS. The origin of the elements in the Universe and hypotheses leading to their diversified spatial abundance. Origin of the Solar System and formation of the Earth in a solid state with variable geochemical composition in vertical succession. Development of the atmosphere, oceans and life on Earth. Evolution of metabolic pathways in living organisms developed over geologic time. Discussion of photosynthesis (supplying the atmosphere in oxygen), chemoautotrophic and anaerobic respiration processes. Comparison of the planetary history of Earth, Mars and Venus.

L 3. ATMOSPHERE. Vertical zonation and structure of the atmosphere, distribution of gaseous and aerosol components. Geological history of troposphere formation based on nitrogen, oxygen, carbon dioxide, and trace amounts of biogenic gases in natural conditions and in conditions modified by human activities. Factors influencing the composition of natural and anthropogenic precipitation. Chemical reactions in the stratosphere: the ozone layer, the freon threat. Models binding variability in the atmosphere with natural global change including climate change.

L 4. LITHOSPHERE. Weathering processes of rocks and the mineral products of weathering (secondary minerals including clay minerals, oxides, zeolites). Characteristics of these secondary minerals. Overview of the basic physical and chemical properties of soil and discussion on soil forming processes. Dominant soil-forming processes in Poland: podzolization, browning, lessivage, gleization, accumulation of organic matter in hydromorphic areas. Discussion on processes controlling soil organic matter quantity and quality: humification, mineralization, decay, fermentation and putrefaction. Soil-forming processes important in other regions of the world: e.g. lateritization or specific forms of weathering in areas built of limestone (terra rossa).

L 5. BIOSPHERE: TERRESTRIAL ECOSYSTEM PRODUCTIVITY. Overview of photosynthesis and respiration processes in extended forms. Clarification of the term ‘net primary production’ and ‘Eddy Fluxes’ – changes resulting from the phenomenon of turbulent flow of air masses. Fate of net primary production and organic detritus. Remote sensing of primary production and biomass. Net primary production and organic matter of soils in the context of global changes.

L 6. BIOSPHERE: BIOGEOCHEMICAL CYCLES IN TERRESTRIAL ECOSYSTEMS. Circulation of nutrients in plants and terrestrial ecosystems (plant associations and soils) as a process inextricably linked with the activity of biological processes. Principles of the annual cycle of matter circulation (and of its various elements) in land plants and multi-annual cycle in soils. Reflections on the biogeochemical balance of matter (varying elemental composition) at the landscape level. Discussion of factors that may significantly affect this balance (anthropogenic factors, fire, animals). Human impact on terrestrial biogeochemical cycles: erosion, fertilization, acid rain, increased nitrogen deposition, increase in the concentration of carbon dioxide in the atmosphere and the global warming effect.

L 7. WETLAND ECOSYSTEMS. Natural attributes of soil-hydrological and ecological features that justify the use of the term "wetland area" (wetland ecosystem). Productivity of wetland ecosystems and resources of accumulated organic matter. Biogeochemical processes controlling the size of organic deposits in wetland ecosystems (mineralization, humus forming processes, fermentation, denitrification, iron and manganese reduction, sulphate reduction, methanogenesis, methane oxidation under aerobic and anaerobic conditions by microbial consortia). Wetlands and surface water quality. Wetlands and global climate changes

L 8. INLAND WATER. Inland water reservoirs (lakes, rivers and estuaries). Ecological factors determining fertility (trophic level) of lakes. Cycles of vertical mixing of lake water and its impact on water trophy. Budget of water resources in rivers. Mixing and trophic level of river water. Budget of estuarine water resources. Mixing and fertility of estuaries. Impact of human management on water trophy and resources.

L 9. OCEANS. Water circulation in oceans and its regional disturbances of global importance to climate (e.g. the El Niňo effect). Chemical composition of ocean water. Diagenesis of sediments (organic matter, opal silica and biogenic carbonates). Maritime biological pump controlling global carbon circulation. Principles of nutrient distribution in the water column. Nutrients limiting primary production of the ocean. Human impact on the disturbance of natural cycle of elements in the ocean. Biogeochemistry of hydrothermal vents. Cycle of marine sulphur. Record of ocean biogeochemical history in bottom sediments.

GLOBAL CYCLES

L 10. GLOBAL WATER CYCLE. Contemporary global water cycle illustrated by models. Cycle of water in the geological past, including Quaternary climatic fluctuations. Water cycle versus climate change: increase of global sea-water level, fluctuations of ranges of glaciers and sea ice, changes of water balance on land.

L 11. GLOBAL COAL CYCLE. Contemporary global circulation of carbon. Variable carbon cycle on Earth in the geological past and the unique composition of Earth’s atmosphere in the Solar System. Fate and biochemical importance of gaseous forms of carbon in the atmosphere (carbon dioxide, carbon monoxide, methane). Linking of the global fate of carbon and oxygen during the geological history and development of the Earth.

L 12. GLOBAL CYCLE OF NITROGEN AND PHOSPHORUS. Dynamics of the transformation of nitrogen forms in the global cycle. Global nitrogen cycle with additional distinction of the marine environment. Global nitrogen cycle in the geological past. Anthropogenic increase in the concentration of nitrous oxide in the atmosphere. Global phosphorus cycle. Detailed discussion of the fate of soil phosphorus, internal phosphorus supply to water from sediments and due to functioning of a microbial loop in the water. Attempt to link the global cycles of carbon, nitrogen and phosphorus.

L13. GLOBAL CYCLE OF SULPHUR AND MERCURY. Geological history of the global sulphur cycle on Earth. The current model and budget of sulphide carbonyl in the atmosphere. Global mercury cycle, an extremely toxic element that can be easily introduced into the atmosphere and spread out globally.

L14. PERSPECTIVES. Attempt to estimate the rate of flow and accumulation sites of the most important elements in the biogeochemical cycles, and quantitatively estimate the human impact on the modification (accelerated turnover) in these cycles. Search for biological and abiotic markers of processes controlling biogeochemical cycles.

On completion of the course, the student:

- knows the most important biogeochemical processes shaping the face of the Earth, can explain the links between its basic spheres: lithosphere, hydrosphere and atmosphere combined by the biosphere, which is the domain of biogeochemistry,

- has basic understanding of the biological, ecological, chemical, geochemical and geological processes, allowing to recognize the complex abiotic - biotic linkages merging the biogeochemical cycle of elements in a coherent current biosphere and their history that developed in the past,

- are aware against simple solutions to complex problems, which are preferred in everyday life, especially in the media. Most of the concepts presented in the course represent more or less probable scientific hypotheses that should be considered with a certain caution, as they were selected by the lecturer from an infinite number of other hypotheses, often equally probable.

Final written examination.

The condition of passing the exam is mastering the material discussed during the classes.

Resit test according to the criteria as above

none