An Ecological System: The Biogeochemical Cycles The water cycle The Carbon Cycle The Nitrogen Cycle The Phosphorus Cycle The cycling of nutrients through the biosphere for use throughout the system by food chains, webs, and the biosphere. The nutrients: carbon, hydrogen, oxygen, Nitrogen, and Phosphorus

Biosphere:5 miles up and 5 miles down

The Water Cycle: Hydrogen and Oxygen Continuously moves throughout the atmosphere, the land, and waters (oceans, lakes and rivers) Water vapor condenses in the air and falls as precipitation then gets back into the air during evaporation Evaporation from plants is called Transpiration

The Water Cycle transpiration

The Carbon and oxygen Cycles: Carbon and Oxygen The continuous movement of carbon and oxygen from non-living into living organisms CO2 in atmosphere build organic molecules Plants use CO2 to produce O2 This exchange of CO2 for O2 is called Respiration (cellular respiration) Combustion or burning releases carbon Burning trees, fossil fuels: oil and coal

The Carbon Cycle

Nitrogen Cycle: Nitrogen (N) Nitrogen Is needed to make proteins (DNA, RNA, Enzymes) Is a process where nitrogen circulates among the air, soil, water, and organisms Nitrogen Fixation: where bacteria that live in soil or on roots, or lightening change chemical composition of N2 into ammonia – a useable form of nitrogen by living organisms

Nitrogen Cycle: Nitrification: The changing of un-useable nitrogen, nitrite, into useable Nitrate De-nitrification: Changes nitrate into nitrogen gas that returns to atmosphere

Biological Nitrogen Fixers Cyanobacteria – blue-green algae Free living soil bacteria Mycorrhizae: Symbiotic bacteria living in root nodules Chemical Fixators: Lightening There are two general types of nitrogen fixers Cyanobacteria – primary producers, e.g., blue/green algae – fix their own carbohydrates Bacteria that require a source of carbohydrates Get it from dead organic matter in soil Get it directly from plants in a symbiotic relationship - mychorhizae

Root nodules on Cassia fasciculata

Nitrogen is available in three soluble forms in soils   ·      Nitrification is a series of processes associated with decomposition, fixation and transformation of N in the soils Nitrates are the form of nitrogen used by plants But nitrogen also exists in soil solutions as ammonia, and nitrite Nitrogen compounds are extremely volatile, breaking down very quickly

The Nitrogen Cycle

Phosphorus Cycle: Phosphorus An important ingredient in DNA and RNA and all proteins Flows in organism in different chemical forms into the surroundings and back into organisms Doesn’t enter atmosphere In soil and rock. Dissolves and is used by plants Plants are eaten by animals, animals die, cycle begins again

Phosphorous Cycle Phosphate – PO4-3 Phosphorous is an extremely important nutrient as well that is limiting to plant growth   ·       There is lots of phosphorous in mineral form Getting it in phosphate, the form taken up by plants, is the big issue in terms of nutrient cycling Microbes again mobilize Phosphorous, i.e. put it in a form that can be used by plants

The Phosphorus Cycle

Cycles compared to Energy Flow Cycles are recycled through the biospere by food webs, the hydrosphere, the biosphere, the geosphere, atmosphere Energy flows through food webs, is made by plants initially from the sun Is used by living organisms, passed on, and is lost into space

Do you see the energy flow and cycles?

Ecological Succession

Ecological Succession The orderly, natural changes and species replacements that take place in the communities of an ecosystem. Over time biotic and abiotic factors create ecological conditions that are suitable for some organisms and unsuitable for others. Changing the ecosystem along the way.

Primary Succession Succession beginning in an area or surface on which there has never been life before Exposed rock Lichen & mosses Grasses, herbs, scrubs, larger scrubs, tree seedlings Aspen, jack Spruce, pines White spruce, Balsam fur, Paper birch climax community pioneer species TIME

Secondary Succession Occurs in a region in which life has existed before, but the previous community structure has been disrupted climax community Frequently seen in North Georgia where cultivated fields like old cotton or soybean fields are abandoned

Secondary Succession What could cause the previous ecological community to have been disrupted? FIRE FLOOD LANDSLIDE

Climax Community

Biomes A large region characterized by a specific type of climate and certain types of plants and animals