BIOGEOCHEMICAL CYCLES INTRODUCTION THE CYCLING PROCESS TWO CYCLES: CARBON CYCLE NITROGEN CYCLE HUMAN IMPACTS GLOBAL WARMING AQUATIC EUTROPHICATION

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2 BIOGEOCHEMICAL CYCLES INTRODUCTION THE CYCLING PROCESS TWO CYCLES: CARBON CYCLE NITROGEN CYCLE HUMAN IMPACTS GLOBAL WARMING AQUATIC EUTROPHICATION

3 BIOGEOCHEMICAL CYCLES: The RECYCLING of MATERIALS through living organisms and the physical environment. BIOCHEMIST: Scientists who study how LIFE WORKS at a CHEMICAL level. The work of biochemists has led to the understanding that LIVING ORGANISMS are composed of some of the SAME elements that are found in air, water, and soil.

4 Although there are 92 elements known to occur naturally on Earth, fewer than 20 elements are presently known to occur in the tissues of living things. For example, only 6 elements make up 99.2 % of human tissue... And pumpkin tissue!!! Look at the table on the following slide to see a comparison between the elements in the EARTH s CRUST, a HUMAN, and a PUMPKIN!

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6 So....you don t really need to dress up like a pumpkin!!! And when you say you feel like dirt, you kind of are like dirt! Oh yeah, and also... THE FOUR ELEMENTS that make up the MAJORITY of LIVING TISSUES are: OXYGEN CARBON HYDROGEN NITROGEN

7 The 4 elements -- O, C, N, and H are cycled constantly between 2 parts of nature: LIVING ORGANISMS PHYSICAL ENVIRONMENT The cycling of these elements is dependent on two types of processes in order to work: BIOLOGICAL PROCESSES GEOLOGICAL PROCESSES

8 BIOLOGICAL PROCESSES The cycling of these elements requires LIVING ORGANISMS, which make up the BIOSPHERE of Earth. What are some examples of BIOLOGICAL PROCESSES? Respiration Photosynthesis Decomposition Assimilation Excretion

9 GEOLOGICAL PROCESSES The cycling of these elements require the PHYSICAL ENVIRONMENT, which INCLUDES: AIR ATMOSPHERE LAND GEOSPHERE WATER - HYDROSPHERE What are some examples of GEOLOGICAL PROCESSES? FOSSILIZATION EROSION COMBUSTION/BURNING WEATHERING SEDIMENTATION

10 CARBON CYCLE NITROGEN CYCLE

11 DEFINITION The cycling of carbon through the atmosphere, the physical environment, and ecosystems.

12 LINK LINK LINK LINK (JOKE) See also Figure 3, p. 63

13 HOW IMPORTANT IS CARBON for LIFE? Carbon is the ELEMENT that is the BACKBONE for ALL LIFE on Earth. In other words, we are CARBON-BASED life forms. HOW DOES CARBON MOVE THROUGH LIVING ORGANISMS? The two main PROCESSES that help cycle CARBON through the BIOSPHERE are: PHOTOSYNTHESIS CELLULAR RESPIRATION

14 WHERE IS CARBON STORED IN THE NON LIVING PHYSICAL ENVIRONMENT? 2 TYPES OF CARBON STORAGE: ORGANIC RESERVOIRS Carbon that has been stored as the result of decomposition of living organisms. These processes are VERY SPECIFIC and take MILLIONS OF YEARS to complete. When DETRITUS gets TRAPPED UNDER: PEAT, it forms COAL OCEANS, it forms OIL and NATURAL GAS INORGANIC RESERVOIRS 3 MAIN AREAS: AIR 0.03 % of air is carbon OCEANS both dissolved (CO2 gas) and in shells (CaCO3 calcium carbonate) LAND in sedimentary rocks, which can be released during volcanic eruptions

15 DEFINITION: The movement of nitrogen through the atmosphere, physical environment and ecosystems.

16 DEFINITION: The movement of nitrogen through the atmosphere, physical environment and ecosystems.

17 LINK LINK LINK

18 WHAT IS NITROGEN USED FOR IN LIVING ORGANISMS? Nitrogen is used to make DNA and PROTEINS. DNA is the GENETIC MATERIAL found in every living cell. WHERE IS MOST NITROGEN FOUND ON EARTH? Most nitrogen on Earth is found in the air. The air is 79% NITROGEN. This atmospheric nitrogen is in the form N2, a gas. Although nitrogen is plentiful in the air, it is UNUSABLE to most living organisms (we cannot simply breathe in nitrogen).

19 HOW DO LIVING ORGANISMS GET NITROGEN? Plants and animals cannot use N2 gas. We can use nitrogen in TWO FORMS: AMMONIA, NH3 NITRATES, NO3 - WHAT ARE THE KEY NITROGEN CYCLE PROCESSES? NITROGEN FIXATION DENITRIFICATION

20 NITROGEN FIXATION Also known as NITRIFICATION Gaseous nitrogen, N2, is converted to usable forms in TWO WAYS: By LIGHTNING By NITROGEN-FIXING BACTERIA These bacteria are found in the ROOT NODULES of LEGUMES such as ALFALFA and CLOVER. DENITRIFICATION DENITRIFYING BACTERIA convert usable forms of nitrogen back into gaseous nitrogen, N2. These bacteria are found in the soil.

21 CARBON CYCLE GLOBAL WARMING and the GREENHOUSE EFFECT NITROGEN CYCLE AQUATIC EUTROPHICATION OZONE DEPLETION

22 Humans have DISRUPTED the CARBON CYCLE in TWO MAIN WAYS: Burning FOSSIL FUELS Increased CO2 DEFORESTATION Decreased O2 production by plants Increased CO2 These INCREASES in CO2 Levels have led to an ENHANCED GREENHOUSE EFFECT.

23 WHAT ARE GREENHOUSE GASES? Gases that have the ability to HOLD HEAT IN the atmosphere. These gases are important to keep the Earth warm enough to sustain life.

24 CARBON DIOXIDE CO2 Sources: Cellular Respiration Combustion (burning) METHANE CH4 Sources: Fossil fuel production and transportation Decomposition Livestock LINK LINK LINK NITROUS OXIDES NOx Sources: Combustion Agricultural Fertilizers Industrial Emissions

25 Humans have DRAMATICALLY INCREASED the amount of greenhouse gases in the atmosphere, leading to the ENHANCED GREENHOUSE EFFECT, or GLOBAL WARMING.

26 Increased spread of disease Rising sea levels and loss of polar ice caps Figure on right is 1979 versus 2005 Loss of freshwater sources More extreme weather Accelerated species extinction

27 LINK GLOBAL WARMING 101 LINK ATLANTIC WALRUS LINK POLAR BEARS LINK GROLAR BEAR

28 Humans have impacted the nitrogen cycle by releasing 2 substances into AQUATIC ECOSYSTEMS: FERTILIZERS UNTREATED HUMAN SEWAGE WHAT ARE FERTILIZERS? Chemicals used to improve crops in agriculture and to aid in lawn care at individual homes. Fertilizers, and untreated human sewage, contain NITRATES and PHOSPHATES. These chemicals LEACH into water ways through groundwater, road runoff, etc.

29 Lakes that have HIGH LEVELS of phosphates and nitrates can undergo EUTROPHICATION AQUATIC EUTROPHICATION: A transformation from an OLIGOTROPHIC LAKE to a EUTROPHIC LAKE.

30 OLIGOTROPHIC LAKE LOW levels of nitrates and phosphates LOW numbers of microorganisms HIGH diversity and numbers of fish CLEAR, DEEP, COLD HIGH d. O2 Not prone to ALGAL BLOOMS EUTROPHIC LAKE HIGH levels of nitrates and phosphates HIGH numbers of microorganisms LOW diversity and numbers of fish TURBID, SHALLOW, WARM LOW d. O2 HIGH RATES of ALGAL BLOOMS algal bloom

31 Humans have impacted the OXYGEN CYCLE through our contributions to OZONE DEPLETION.

32 OZONE LAYER: Located in the Earth s ATMOSPHERE. Made up of OZONE, a bluish-hued gas that has the chemical formula O3. Serves as a PROTECTIVE LAYER, filtering out damaging UV rays.

33 To understand the ozone layer, it is helpful to know the LAYERS OF THE ATMOSPHERE: TROPOSPHERE: Where we live, where weather occurs STRATOSPHERE: Where ozone is located MESOSPHERE: Middle Layer THERMOSPHERE Also known as IONOSPHERE High energy ions and Northern and Southern Lights EXOSPHERE Boundary to space

34 8O % of the Earth s Ozone has depleted as the result of humans using CFCs (chlorofluorocarbons) and other ozone depleting chemicals. In the past, CFCs were found in a variety of household items, including: Refrigerators Aerosol sprays Fire extinguishers These CFCs would be released into the air, and make their way up to the stratosphere and break down O3. TODAY, CFCs are banned in Canada, as well as in several other countries. LINK

35 The effect of ozone depletion is INCREASED EXPOSURE to highly damaging UV rays. In humans, high UV exposure can lead to increased risks of skin cancer, eye damage, and immunosuppression.

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37 Something to Think About Give Earth a Hand