Biogeochemical Pathways

1. Biogeochemical Pathways Flows, Fluxes, and Cycles The Movement of Energy and Chemicals

2. We are what we eat • Everything is connected to everything else • The balance of nature • There ain’t no such thing as a free lunch • Our ecological footprint

3. Endangered Species • In 1973 Congress enacted The Endangered Species Act in an effort to protect plants and animals and their habitats that were endangered • Currently, 632 species are categorized as endangered (326 are plants) and 190 threatened species (78 are plants) • The statute prohibits any action that results in "taking" a listed species or adversely affects habitat • And importing, exporting, and trading all or parts of listed species

4. Endangered Species • EPA's decision to register a pesticide is based in part on the risk of adverse effects on endangered species as well as environmental fate - how a pesticide will affect habitat • Under Federal Insecticide Fungicide and Rodenticide Act (1988) EPA can suspend the use of certain pesticides or restrict their use if an endangered species will be adversely affected • Under a new program, EPA, FWS, and the USDA are distributing hundreds of county bulletins that include habitat maps, pesticide use eliminations, and other actions required to protect listed species

5. Chemical Basis of Earth • All matter is composed of chemical elements • Some occur naturally – some are manufactured • Organic matter contains about 20 elements particularly • oxygen • carbon • hydrogen • nitrogen • Elements may be grouped into compounds • Matter usually composed of compounds

6. Bases of Life - Chemicals • Organic Matter (living) v Inorganic Matter (non-living) • Oxygen is used to release energy from chemical compounds (nutrients) that drive metabolic activities (respiration) • Carbon dioxide is released as a waste product during metabolic reactions (respiration)

7. Earth’s Geology • Structure (NASA) • Chemical composition (by mass) • 34.6% Iron • 29.5% Oxygen • 15.2% Silicon • 12.7% Magnesium • 2.4% Nickel • 1.9% Sulfur • 0.05% Titanium • Most rocks - igneous, sedimentary, and metamorphic - are composed of minerals • Minerals are naturally occurring inorganic solids with a crystalline structure and a distinct chemical composition - compounds

8. Rocks – Combinations of Chemicals • Over 2000 minerals have been identified • Metallic and non-metallic • Sulfides – metallic elements in combination with the element sulfur • Halides - fluorine, chlorine, iodine, and bromine, soluble in water • Oxides - compounds of one or more metallic elements combined with oxygen, water, or hydroxyl (OH) • Carbonates – contains one or more metallic elements combined with the compound CO3 • Sulfates – contains one or more metallic elements combined with the compound SO4 • Phosphates – contains one or more metallic elements combined with the compound PO4 • Silicates – the largest group of minerals, containing silicon and oxygen • Organic minerals contain hydrocarbons

9. Bases of Life – Solar Radiation

10. Earth’s Atmosphere • Layer of gases surrounding Earth kept in place by the Earth's gravity • Contains • 78% nitrogen • 21% oxygen • 0.93% argon • 0.04% carbon dioxide • trace amounts – methane, neon, helium, ozone, nitrous oxides • 1%-4% water vapor • Commonly known as air • Absorbs ultraviolet solar radiation and reduces temperature extremes – gaseous envelope

11. Solar Radiation

12. Solar Radiation

13. The Greenhouse Effect

14. Basis for Life - Water

15. Hydrosphere • Water is the most abundant compound in living things and makes up two-thirds of the weight of adults • Most metabolic reactions occur in water • Major component of blood therefore important in transporting materials in the body • Carries waste materials and can absorb and transport heat

16. Water • The importance of water • Covers three-fourths of the earth’s surface • Comprises 60-70% wt of the living world • Water can exist as a liquid, gas, or sold • Distributed horizontally and vertically through various process – condensation, precipitation, drainage, evaporation, melting • High specific heat • Dissolves virtually everything • Able to transport – dissolved, suspended • Constantly in motion

17. Water Properties

18. Water Distribution

19. The Hydrological Cycle

20. Chemicals

21. Carbon • An abundant element in the Universe, along with hydrogen, helium, and oxygen (O) • The building block of life – basis of all organic substances • Carbon cycles can be divided into two • geological processes operating over millions of years • biophysical processes operating over shorter time periods • The carbon content established during the earth’s formation as planetesimals (small bodies that formed from the solar nebula) and carbon-containing meteorites that bombarded the planet’s surface • The concentration of carbon in living matter (18%) is almost 100 times greater than its concentration in the earth (0.19%) • Organisms extract carbon from their nonliving environment

23. Carbon exists in the nonliving environment as • carbon dioxide in the atmosphere and dissolved in water • carbonate rocks • deposits of coal, petroleum, and natural gas derived from once-living things • dead organic matter (humus) in soil

24. Carbon enters the biotic world through the action of autotrophs • photoautotrophs, like plants and algae, that use solar energy (sunlight) to convert carbon dioxide to organic matter • chemoautotrophs – bacteria and archaea that use the energy derived from the oxidation of molecules in their substrate • Carbon returns to the atmosphere and water by • respiration, as carbon dioxide • burning • decay (carbon dioxide if oxygen is present, methane if it is not)

25. Carbon and Biological Process • Nearly all forms of life depend on • the production of organic matter by green plants that absorb solar energy and carbon dioxide from the atmosphere and water and chemical elements from a substrate - photosynthesis • the breakdown of this organic matter during respiration to produce the chemical energy necessary for all metabolic activities • Respiration by all living organisms return the biologically-fixed carbon back to the atmosphere • The amount of carbon taken up by photosynthesis and released back to the atmosphere by respiration each year is considerably larger than the amount of carbon that moves through the geological cycle

27. Geological Processes • In weathering, carbonic acid, derived from atmospheric carbon dioxide and water, combines with calcium and magnesium in the Earth’s crust to form insoluble carbonates • Through erosion, the carbonates are washed into the ocean and form sediments • These sediments are drawn into earth’s mantle by subduction at the edges of continental plates • The carbon is then returned to the atmosphere as carbon dioxide during volcanic eruptions • Weathering and erosion, subduction and volcanism controls atmospheric carbon dioxide concentrations over time periods of hundreds of millions of years • The oldest sediments suggest that, before life evolved, the concentration of atmospheric carbon dioxide may have been one-hundred times that of the present • Ice core samples from Antarctica and Greenland suggest that carbon dioxide concentrations during the last ice age (20,000 years ago) were half of today’s values

28. Ocean Sink of Carbon • Marine organisms consume and release huge quantities of carbon dioxide • In contrast to land, carbon cycles between photosynthesis and respiration vary rapidly, so that there is virtually no storage of carbon as there is on land • Photosynthetic microscopic phytoplankton are consumed by respiring zooplankton within a matter of days to weeks • Some of the carbon make shells of calcium carbonate settles to the bottom to form sediments • When photosynthesis exceeded respiration organic matter slowly built up over millions of years to form coal and oil deposits • These biological processes remove carbon dioxide from the atmosphere and store carbon in geologic sediments

30. Mineral “Cycles”

31. Nitrogen Cycle

33. Phosphorus

34. Phosphorus

35. Ecological Energetics

36. Food Chains • Plants produce organic matter using solar energy • Animals, are consumers because they eat plants and/or animals • herbivores • carnivores • phytoplankton → small fishes → seals → killer whales • Animals can be omnivores • Decomposers, bacteria and fungi, consumers that feed on decaying organic matter • These releases chemicals back into the soil soup to be taken up by plants as nutrients

39. Food Chain Rules • Relationship between organisms - plant-herbivore, predator-prey • Most animals are part of more than one food chain and eat more than one kind of food in order to meet their energy requirements • These interconnected food chains form a food web

42. Bioaccumulation • As organic matter is consumed the chemicals may become concentrated • Bioconcentration and Biomagnification (Dave McShaffrey, Marietta College) • Bioaccumulation of Mercury (Purdue Research Foundation) • Bioaccumulation Studies (ak Ridge National Lab)

43. Ecological Energetics • Along the food chain less and less energy remains available • Most food chains have no more than four or five links

45. Ecosystems • The living community • the plants and animals inhabiting an area • Along with the particular set of ecological conditions to which they must adjust • solar radiation, water, chemistry, ….

46. Ecosystems

48. Ecosystem Variety • Wetlands (EPA) • Lakes (Great Lakes Information Network) • Prairie (Northern Prairie Wildlife Research Center) • Minnesota Big Woods (Minnesota DNR) • Minnesota Scientific and Natural Areas (Minnesota DNR) • Ecological Classification of Minnesota (Minnesota DNR) • Biomes (University of California Museum of Paleontology)

49. Wastewater Treatment • Wastewater Treatment Principles and Regulation (Ohio State University Extension) • Wastewater Treatment (Friends Of the Arcata Marsh) • Environmental Services (Metropolitan Council)

50. Environmental Protection Agency • Human Health • Pesticides • Lead in Paint, Dust, and Soil • Mercury • Superfund • Wastes