Objectives  Explain Earth’s hydrologic and biogeochemical cycles.  Outline in detail the following cycles:  Oxygen Cycle  Carbon Cycle  Nitrogen Cycle  Phosphorus Cycle

Energy, Carbon, & Ecosystems  Earth is an open system when in comes to energy  Meaning that sunlight is constantly providing new energy to be entered into the ecosystem by plants  Where matter is concerned (the elements), the Earth is closed system  There is only so much matter on Earth, and we can not add to it  The amount of carbon that is present on Earth now, was present millions of years ago

Hydrologic CycleHydrologic Cycle  Also known as the water cycle  Cycles from the atmosphere, the surface, below ground, and back up  Water is involved in almost all organisms, as we are made primarily of water  Therefore water has a stop over in organisms, which we put back into the Earth either through waste or when we die

Hydrologic CycleHydrologic Cycle 1.Precipitation (rain or snow) falls to the Earth 2.Precipitation seeps into the ground or joins any body of water already existing (ponds, streams, lakes) a)It can also make puddles or temporary pools 3.Groundwater may eventually run into the oceans or other large bodies of water (most of which lead to the ocean eventually) 4.Stored water evaporates from these larger bodies into the atmosphere a)Water is also released into the atmosphere by plants, a process called transpiration 5.The cycle is completed when that evaporated water condenses and forms more precipitation.

Biogeochemical CyclesBiogeochemical Cycles  Most organisms are made up of oxygen, carbon, nitrogen, and hydrogen  With phosphorus and sulfur also being important for life  These elements are finite (closed system), therefore they must cycle through the ecosystem, just as water does  Biogeochemical Cycle is the movement of a particular chemical through an ecosystem  4 Major Cycles:  The Oxygen Cycle  The Carbon Cycle  The Nitrogen Cycle  The Phosphorus Cycle

The Oxygen CycleThe Oxygen Cycle  Organisms need oxygen for cellular respiration (remember?), but other processes are also involved  Plants: release Oxygen as a waste product during photosynthesis  Humans/Animals: breath in Oxygen and release carbon dioxide as waste  Oxygen is also cycled through the ecosystem by attachment to other elements

The Carbon CycleThe Carbon Cycle  Carbon is the building block of life, it flows through the environment into living organisms and back into the environment  Carbon is stored both in the abiotic parts of an ecosystem, as well as the biotic parts of an ecosystem

The Carbon Cycle: AbioticThe Carbon Cycle: Abiotic  Carbon can be found in solid, liquid, and gaseous states  Sources include:  Carbon dioxide (gas)  bicarbonate (liquid)  fossil fuels (liquid)  carbonate rocks (solid)  dead organic matter (solid)

The Carbon Cycle: BioticThe Carbon Cycle: Biotic  Carbon flows between plants and animals  Plants:  Convert carbon dioxide from air into organic material for the plant’s growth  Plants are then eaten by other animals, thus transferring their carbon to that animal  Carbon is then transferred from one animal to another as animals eat each other  Carbon is returned to the atmosphere through respiration(carbon dioxide) or though the decomposition of dead organisms  Burning of fossil fuels or wood, as well as other emissions, adds to the carbon dioxide in the atmosphere  Carbon is also released as methane, which is emitted by wetlands, landfills, and livestock(termites…)

The Carbon Cycle: Carbon Sinks  Not all carbon molecules are going to move freely through the ecosystem  Some areas store carbon for long periods of time, we call these carbon sinks  Examples of Carbon Sinks:  Forests: carbon is stored in cellulose of wood  Can you think of others?  Do you remember where you heard this term before?

The Nitrogen CycleThe Nitrogen Cycle  78% of the Earth’s atmosphere is nitrogen gas  But organisms only use nitrogen in the form of ions  Bacteria can convert gaseous nitrogen into ammonia(an ion), using a process called nitrogen fixation  Nitrogen Fixing Bacteria  Live in small nodules (outgrowths) on the roots of plants  Others live freely in the soil  Nitrogen fixing bacteria release ammonia, which is changed into ammonium by the addition of hydrogen atoms  Some of this ammonium is take up by plants, but most is used by nitrifying bacteria as an energy source

The Nitrogen CycleThe Nitrogen Cycle  Nitrifying Bacteria: change ammonium into nitrate  Nitrates released by the bacteria are taken up by plants, which convert them into organic compounds  Nitrogen is exchanged through the cycle of the ecosystem, until it comes back as dead matter  Decomposers break down the dead organic matter, and the nitrogen returns to the soil as ammonium (this process is called ammonification)

The Nitrogen CycleThe Nitrogen Cycle  Denitrifying bacteria use oxygen as an oxygen source, releasing nitrogen gas back into the atmosphere  Some nitrogen also enters the soil through nitrogen fixation by lightening, which also sends some nitrogen into the atmosphere as gas  Nitrogen can then combine with oxygen in the air, which forms nitrogen oxide,  Nitrogen oxide joins with rainwater to form nitrates, which are absorbed by the soil

The Phosphorus CycleThe Phosphorus Cycle  Does not include an atmospheric component  Cycle begin when phosphate is released by the weathering of rocks  Phosphate is taken up by plants and fungi  Phosphates are transferred from producer to consumer through the food web  When organisms dies they are broken down by decomposers, releasing the phosphorus back into the soil or water

The Phosphorus CycleThe Phosphorus Cycle  Some phosphorus will be trapped at the bottom of a body of water by sediment  When the sediment becomes rock the cycle will begin all over again  Mining and agriculture also add to the overall amount of phosphorus in the environment  Excessive phosphorus in an ecosystem causes significant problems  Limits growth of plants  Algal blooms  All which affect the wildlife and/or indigenous species

Output  Draw a picture illustrating the interdependence of two of the mentioned cycles. Be sure to label and describe the important steps of each cycle.