BIOGEOCHEMICAL-CYCLE - ENVIRNMENTAL SCIENCE

GE 10

1. Biogeochemical Cycle

2. The biogeochemical cycle involves the movement of elements and compounds among the interactions that exist between the atmosphere (air), hydrosphere (water), lithosphere (rock or land), and biosphere ( living organisms) . INTRODUCTION

3. Biogeochemical cycles can be classed as: Carbon-Oxygen Cycle Water Cycle Nitrogen Cycle Sedimentary Cycle Types of Biogeochemical Cycle

4. Carbon-Oxygen Cycle

5. The carbon cycle describes the movement of carbon as it is recycled and reused throughout the biosphere, as well as long-term processes of carbon sequestration (storage) to and release from carbon sinks . C omprises a sequence of events that are key to making Earth capable of sustaining life.

6. Step 1: Photosynthesis P lants obtain carbon dioxide from the air, through photosynthesis incorporate carbon into their tissues.

7. Step 2: Decomposition B reakdown of chemical bonds formed during the construction of plant and animal tissue.

8. Step 3: Marine Plankton Remains C arbon that is not released back into the atmosphere eventually become fossil fuels (coal, oil and natural gas ). Step 4: Combustion (Human & Natural) P rocess of burning may return the carbon in oil, coal, natural gas, and wood to the atmosphere. That organic molecules are rapidly oxidized (combined with oxygen) and converted carbon dioxide and water with an accompanying release of light and heat.

9. Oxygen Cycle Oxygen is found in several parts of the ecosystem, from the air we breathe (Atmosphere), the water bodies on the planet (Hydrosphere), inside all the biological beings (Biosphere) and inside the earth’s crust (Lithosphere ). T he sustainable development of the living components of the ecosystem.

10. Production of Oxygen There are two ways in which Oxygen is formed in nature. They are: Photosynthesis - A complex process used by green plants where the leaves of the green plants with the help of sunlight and chlorophyll convert carbon dioxide and water into Glucose and O xygen.

11. Photodissociation - T he formation of Oxygen molecules when sunlight interacts with the water vapor present in the atmosphere .

12. Hydrologic (Water) Cycle

13. The water cycle consists of five major processes: Evaporation Condensation Precipitation Surface Runoff Transpiration

14. Evaporation T he process of a liquid's surface changing to a gas. In the water cycle, liquid water (in the ocean, lakes, or rivers) evaporates and becomes water vapor.

15. Condensation The process of a gas changing to a liquid. In the water cycle, water vapor in the atmosphere condenses and becomes liquid.

16. D escribes any liquid or solid water that falls to Earth as a result of condensation in the atmosphere. C an occur in the form of rain, snow, and hail. Precipitation

17. Surface Runoff D escribes a variety of ways liquid water moves across land .

18. Transpiration P rocess of water vapor being released from plants and soil. W ater is absorbed by plants (usually through the roots) from water that is in the soil.

19. Nitrogen Cycle

20. A biogeochemical process through which nitrogen is converted into many forms, consecutively passing from the atmosphere to the soil to organism and back into the atmosphere. Nitrogen gas exists in both organic and inorganic forms. Organic nitrogen exists in living organisms, and they get passed through the food chain by the consumption of other living organisms. It involves several processes such as Nitrogen Fixation, Nitrification, Denitrification, Ammonification/Decay.

21. Nitrogen Fixation O ccur either by atmospheric fixation which involves lightening, or industrial fixation by manufacturing ammonia under high temperature and pressure conditions.

22. Types of Nitrogen Fixation Atmospheric fixation - A natural phenomenon where the energy of lightning breaks the nitrogen into nitrogen oxides, which are then used by plants.

23. Industrial nitrogen fixation - It is a man-made alternative that aids in nitrogen fixation by the use of ammonia. Ammonia is produced by the direct combination of nitrogen and hydrogen. Later, it is converted into various fertilizers such as urea. Biological nitrogen fixation: - Bacteria like Rhizobium and blue-green algae transform the unusable form of nitrogen into other compounds that are more readily usable. These nitrogen compounds get fixed in the soil by these microbes.

24. Nitrification T he ammonia is converted into nitrate by the presence of bacteria in the soil. Nitrites are formed by the oxidation of ammonia with the help of Nitrosomonas bacteria species. Later, the produced nitrites are converted into nitrates by Nitrobacterium.

25. Denitrification T he process in which the nitrogen compounds make their way back into the atmosphere by converting nitrate into gaseous nitrogen. Denitrification is carried out by the denitrifying bacterial species Clostridium and Pseudomonas, which will process nitrate to gain oxygen and gives out free nitrogen gas as a by product.

26. Ammonification/Decay The decomposers, namely bacteria or fungi present in the soil, convert the organic matter back into ammonium. This process of decomposition produces ammonia, which is further used for other biological processes.

27. Sedimentary Cycle/Rock Cycle

28. I nclude the leaching of minerals and salts from the Earth’s crust, which the settle as sediment or rock before the cycle repeats . There are three main types of rocks: sedimentary, igneous, and metamorphic. Each of these rocks are formed by physical changes such as melting, cooling, eroding, compacting, or deforming

29. Sedimentary Rocks F ormed from pieces of other existing rock or organic material. There are three different types of sedimentary rocks: clastic, organic (biological), and chemical. Clastic sedimentary rocks, like sandstone, form from clasts, or pieces of other rock.

30. Organic sedimentary rocks, like coal, form from hard, biological materials like plants, shells, and bones that are compressed into rock. Chemical sedimentary rocks, like limestone, and flint, form from chemical precipitation. A chemical precipitate is a chemical compound for instance, calcium carbonate, salt, and silica that forms when the solution it is dissolved in, usually water, evaporates and leaves the compound behind.

31. Metamorphic Rocks R ocks that have been changed from their original form by immense heat or pressure. Metamorphic rocks have two classes: Foliated Nonfoliated Foliation is the aligning of elongated or platy minerals, like hornblende or mica, perpendicular to the direction of pressure that is applied. An example of this transformation can be seen with granite, an igneous rock.

32. Nonfoliated rocks are formed the same way, but they do not contain the minerals that tend to line up under pressure and thus do not have the layered appearance of foliated rocks. Sedimentary rocks like limestone , and sandstone when given enough heat and pressure. Nonfoliated rocks can also form by metamorphism, which happens when magma comes in contact with the surrounding rock.

33. Igneous Rocks A re formed when molten hot material cools and solidifies. When they are formed inside of the earth, they are called intrusive, or plutonic, igneous rocks. If they are formed outside or on top of Earth’s crust, they are called extrusive, or volcanic, igneous rocks. Granite and diorite are examples of common intrusive rocks. They have a coarse texture with large mineral grains, indicating that they spent thousands or millions of years cooling down inside the earth, a time course that allowed large mineral crystals to grow.

34. The most important geological processes that lead to the creation of sedimentary rocks are erosion, weathering, dissolution, precipitation, and lithification. Erosion and weathering include the effects of wind and rain, which slowly break down large rocks into smaller ones. Erosion and weathering transform boulders and even mountains into sediments, such as sand or mud.

35. Dissolution is a form of chemical weathering. With this process, water that is slightly acidic slowly wears away stone. Precipitation and lithification are processes that build new rocks or minerals. Precipitation is the formation of rocks and minerals from chemicals that precipitate from water . Finally, lithification is the process by which clay, sand, and other sediments on the bottom of the ocean or other bodies of water are slowly compacted into rocks from the weight of overlying sediments.

36. Sedimentary rocks can be organized into two categories. The first is detrital rock , which comes from the erosion and accumulation of rock fragments, sediment, or other materials categorized in total as detritus, or debris. The other is chemical rock , produced from the dissolution and precipitation of minerals.