1. CHAPTER 3 -part 2- Biogeochemical Cycles

2. 3-4 What Happens to Matter in an Ecosystem?
Concept 3-4 Matter, in the form of nutrients, cycles within and among ecosystems and the biosphere, and human activities are altering these chemical cycles.

3. Nutrients Cycle in the Biosphere
Biogeochemical cycles, nutrient cycles
Hydrologic
Carbon
Nitrogen
Phosphorus
Sulfur
Nutrients may remain in a reservoir for a period of time

4. Water Cycles through the Biosphere
Natural renewal of water quality: three major processes
Evaporation
Precipitation
Transpiration
Alteration of the hydrologic cycle by humans
Withdrawal of large amounts of freshwater at rates faster than nature can replace it
Clearing vegetation
Increased flooding when wetlands are drained

5. Figure 3.16: Natural capital.
Condensation
Condensation
Ice and snow
Transpiration
from plants
Precipitation to land
Evaporation of
surface water
Evaporation
from ocean
Runoff
Lakes and
reservoirs
Precipitation to ocean
Runoff
Increased runoff on land covered with crops, buildings and pavement
Infiltration and percolation into aquifer
Increased runoff from cutting forests and filling wetlands
Runoff
Figure 3.16: Natural capital.
This diagram is a simplified model of the water cycle, or hydrologic cycle, in which water circulates in various physical forms within the biosphere. Major harmful impacts of human activities are shown by the red arrows and boxes. Question: What are three ways in which your lifestyle directly or indirectly affects the hydrologic cycle?
Groundwater in aquifers
Overpumping of aquifers
Water pollution
Runoff
Ocean
Natural process
Natural reservoir
Human impacts
Natural pathway
Pathway affected by human activities
Fig. 3-16, p. 67

6. Glaciers Store Water
Figure 3.17: Hubbard glacier in the U.S. state of Alaska stores water for a long time as part of the hydrologic cycle. However, mostly because of recent atmospheric warming, many of the world’s glaciers are slowly melting.
Fig. 3-17, p. 68

7. Water Erodes Rock in Antelope Canyon
Figure 3.18: Water flowing over the earth’s surfaces for millions of years played a major role in the formation of the Antelope Canyon in the U.S. state of Arizona.
Fig. 3-18, p. 69

8. Science Focus: Water’s Unique Properties
Properties of water due to hydrogen bonds between water molecules:
Exists as a liquid over a large range of temperature
Changes temperature slowly
High boiling point: 100˚C
Adhesion and cohesion
Expands as it freezes
Solvent
Filters out harmful UV

9. Hydrogen Bonds in Water
Figure 6 Hydrogen bond: The
slightly unequal sharing of electrons
in the water molecule creates a
molecule with a slightly negatively
charged end and a slightly positively
charged end. Because of this electrical
polarity, the hydrogen atoms
of one water molecule are attracted
to the oxygen atoms in other water
molecules. These fairly weak forces
of attraction between molecules
(represented by the dashed lines)
are called hydrogen bonds.
Supplement 4, Fig 6

10. Carbon Cycle Depends on Photosynthesis and Respiration
Link between photosynthesis in producers and respiration in producers, consumers, and decomposers
Additional CO2 added to the atmosphere
Tree clearing
Burning of fossil fuels
Warms the atmosphere

11. Carbon dioxide in atmosphere Respiration
Photosynthesis
Animals (consumers)
Burning fossil fuels
Diffusion
Forest fires
Plants (producers)
Deforestation
Transportation
Respiration
Carbon in plants (producers)
Carbon dioxide dissolved in ocean
Carbon in animals (consumers)
Decomposition
Carbon in fossil fuels
Marine food webs Producers, consumers, decomposers
Figure 3.19: Natural capital.
This simplified model illustrates the circulation of various chemical forms of carbon in the global carbon cycle, with major harmful impacts of human activities shown by the red arrows. Question: What are three ways in which you directly or indirectly affect the carbon cycle?
Carbon in limestone or dolomite sediments
Compaction
Process
Reservoir
Pathway affected by humans
Natural pathway
Fig. 3-19, p. 70

12. Increase in Atmospheric Carbon Dioxide, 1960-2009
Figure 14 This graph shows the atmospheric concentration
of carbon dioxide (cO2) measured at a major
atmospheric research center in Mauna Loa, Hawaii,
1960–2009. The annual fluctuation in CO2 values
occurs because land plants take up varying amounts of
CO2 in different seasons. (Data from Scripps Institute
of Oceanography, 2010, and U.S. Energy Information
Agency, 2010)
Supplement 9, Fig 14

13. Nitrogen Cycles through the Biosphere: Bacteria in Action (1)
Nitrogen fixed by lightning
Nitrogen fixed by bacteria and cyanobacteria
Combine gaseous nitrogen with hydrogen to make ammonia (NH3) and ammonium ions (NH4+)
Nitrification
Soil bacteria change ammonia and ammonium ions to nitrate ions (NO3-)
Denitrification
Nitrate ions back to nitrogen gas

14. Nitrogen Cycles through the Biosphere: Bacteria in Action (2)
Human intervention in the nitrogen cycle
Additional NO and N2O in atmosphere from burning fossil fuels; also causes acid rain
N2O to atmosphere from bacteria acting on fertilizers and manure
Destruction of forest, grasslands, and wetlands
Add excess nitrates to bodies of water
Remove nitrogen from topsoil

15. Nitrates from fertilizer runoff and decomposition
Process
Nitrogen in atmosphere
Denitrification by bacteria
Reservoir
Nitrification by bacteria
Pathway affected by humans
Natural pathway
Nitrogen in animals (consumers)
Electrical storms
Nitrogen oxides from burning fuel and using inorganic fertilizers
Volcanic activity
Nitrogen
in plants (producers)
Decomposition
Nitrates from fertilizer
runoff and decomposition
Uptake by plants
Figure 3.20: Natural capital.
This diagram is a simplified model of the circulation of various chemical forms of nitrogen in the nitrogen cycle in a terrestrial ecosystem, with major harmful human impacts shown by the red arrows. Question: What are three ways in which you directly or indirectly affect the nitrogen cycle?
Nitrate in soil
Nitrogen loss
to deep ocean sediments
Nitrogen
in ocean sediments
Bacteria
Ammonia in soil
Fig. 3-20, p. 71

16. Human Input of Nitrogen into the Environment
Figure 16 Global trends in the annual inputs of nitrogen
into the environment from human activities, with
projections to 2050, are shown in this graph. (Data
from 2005 Millennium Ecosystem Assessmentt)
Supplement 9, Fig 16

17. Phosphorus Cycles through the Biosphere
Cycles through water, the earth’s crust, and living organisms
Limiting factor for plant growth
Impact of human activities
Clearing forests
Removing large amounts of phosphate from the earth to make fertilizers
Erosion leaches phosphates into streams

18. Pathway affected by humans
Process
Reservoir
Pathway affected by humans
Natural pathway
Phosphates in sewage
Phosphates in fertilizer
Plate tectonics
Phosphates in mining waste
Runoff
Runoff
Sea birds
Runoff
Phosphate in rock (fossil bones,
guano)
Erosion
Ocean food webs
Animals (consumers)
Phosphate dissolved
in water
Phosphate in shallow ocean sediments
Phosphate in deep ocean sediments
Figure 3.21: Natural capital.
This is a simplified model of the circulation of various chemical forms of phosphorus (mostly phosphates) in the phosphorus cycle, with major harmful human impacts shown by the red arrows. Question: What are three ways in which you directly or indirectly affect the phosphorus cycle?
Plants (producers)
Bacteria
Fig. 3-21, p. 73

19. Sulfur Cycles through the Biosphere
Sulfur found in organisms, ocean sediments, soil, rocks, and fossil fuels
SO2 in the atmosphere
H2SO4 and SO4-
Human activities affect the sulfur cycle
Burn sulfur-containing coal and oil
Refine sulfur-containing petroleum
Convert sulfur-containing metallic mineral ores

20. Sulfur dioxide in atmosphere
Sulfuric acid and Sulfate deposited
as acid rain
Burning coal
Refining fossil fuels
Smelting
Sulfur in animals (consumers)
Dimethyl sulfide a bacteria byproduct
Sulfur in plants (producers)
Mining and extraction
Uptake
by plants
Sulfur
in ocean sediments
Figure 3.22: Natural capital.
This is a simplified model of the circulation of various chemical forms of sulfur in the sulfur cycle, with major harmful impacts of human activities shown by the red arrows. Question: What are three ways in which your lifestyle directly or indirectly affects the sulfur cycle?
Decay
Decay
Process
Sulfur
in soil, rock
and fossil fuels
Reservoir
Pathway affected by humans
Natural pathway
Fig. 3-22, p. 74