APES Test 2 Videos and Nitrogen Worksheet Flashcards
Ecosystem def
an ecosystem is a community of living organisms in conjunction with the non-living components of their environment, interacting a system
Interspecific competition
competition between diff species, is harmful and species work to avoid it
Resource partitioning
occurs when species use limiting resources in diff ways, places, or at diff times, in an attempt to reduce competition
Intraspecific competition:
occurs when individuals must fight for the same resource that all members of a species need to survive (intraspecific competition makes a species stronger and better adapted to its environment, triggers survival of the fittest and evolution)
Carbon cycle
Photosynthesis and cellular respiration are important processes
For fast carbon cycling, main reservoir is atmosphere
Carbon stays in atmosphere for relatively brief amount of time
Decomposition of organic material, decomposers organisms help:
Return CO2 to the atmosphere through cellular respiration
Return carbon to the soil or water through breakdown of sugars in the bodies they are decomposing
Sedimentation and burial of organic material (organic sediments, calcium carbonate sediments) can result in a MUCH LONGER sequestration of carbon compounds, once carbon is buried, it is essentially removed from fast carbon cycle
Deep ocean sediments and fossil carbon (coal, oil, gas) are largest reservoirs of carbon…and these are result of sedimentation and burial
Long term carbon reservoirs can return to carbon cycles through
Fossil fuel extraction and combustion (quick return to cycling)
Uplift and weathering of limestone (slow return to cycling)
Nitrogen cycle
Fixation
Fixed by lighting (abiotic) or microbes in soil/root nodules (biotic)
Ammonification
Ammonia converted to ammonium by soil bacteria; ammonia can also be added by decay of organic material
Nitrification
Ammonium to nitrites to nitrates
Assimilation
Nitrates uptaken by plants through roots (then to animals)
Denitrification
Ammonium can be converted back into atmospheric nitrogen (N2) by soil bacteria
Plants can take ammonia and ammonium directly, but also assimilate nitrates
Most reservoirs of nitrogen store the element for short periods of time, there are few substantial geologic stores of nitrogen
Phosphorus Cycle
Slow cycle, mainly driven by geologic processes
Has no atmosphere phase
Because of lack of atmospheric phosphorus and length of time it takes to cycle phosphorus is a limiting factor in ecosystems
Producers need phosphorus to grow, makes phosphorus vitally important, fertilizer contains phosphorus
Major reservoir for phosphorus is ocean sediments
Sediments in rock sar e major reservoir of phosphorus, phosphorus in rocks through process of uplift and weathering becomes dissolved in the soil
From the soil phosphorus, it can be dissolved into lakes/streams OR taken up through assimilation into terrestrial food webs through producers and later on consumers
Process of runoff will take some dissolved phosphorus from lakes and streams and some from terrestrial food webs and ecosystems which will runoff into aquatic food webs
Phosphorus can then be taken up by producer organisms there also through assimilation
Phosphorus from runoff can also be dissolved in ocean, and if it’s dissolved it will eventually become sedimented through sedimentation and end up in ocean sediments, then through lithification ocean sediments will become rocks
Volcanic processes can reduce aerosol phosphorus, there is no atmospheric storage, volcano aerosols only hang around for short period of time, major processes are terrestrial and aquatic through geologic process
Water Cycle
Ice caps and groundwater reserves are smaller, but still vital reservoirs (freshwater)
Sun is driver of water cycle
Sublimation
Solid to gaseous without passing through liquid
Evaporation
Movement of water into the atmosphere
Condensation
Once water has moved up into atmosphere, has to come down
Then precipitation, dew, fog drip
Once its back in terrestrial or aquatic ecosystems, collects in ice, snow, glaciers, rivers, as soil moisture, freshwater lakes, saline lakes, wetlands, and ocean,
Surface runoff and snowmelt runoff help to return water to rivers and freshwater lakes
Any time precipitation falls on area that can’t absorb it, end up with runoff, goes into body of water, lakes, rivers, streams, etc.
Water that penetrates into terrestrial ecosystems, enters back into ground through infiltration and seepage, percolates down
Then seeps back up into springs, lakes, feed from bottom if
Can also end up deeper underground in groundwater storage
If in ground water storage, water will eventually end up back in ocean, after short or long period of time
Acidic soils can result in lower bacterial activity in soils. How do you think acidic conditions will affect the amount of available nitrogen in soils?
There will be less available nitrogen in soil because there is less bacteria breaking down ammonia into nitrates.
How do you think nitrogen gets in water (not including nitrogen fixation)?
When it rains, nitrogens run off from the land into water.
What do you think will happen if too much nitrogen ends up in soil or water? Can you think of an area where this may be occurring?
If too much nitrogen ends up in the soil, this can give an advantage to an invasive species or just allow specific species to have a massive advantage over all others because they are better suited to high nitrogen. In the water, high nitrogen causes aquatic plants to grow much more. These plants eventually decompose, which uses a lot of oxygen, meaning that the overall oxygen level in the area decreases significantly. This is called hypoxia, and causes many species to die because there is not enough oxygen to support them. An area where high nitrogen in the soil may be occurring is the Midwest due to the high amount of farming.
Explain the role of detritus in the nitrogen cycle.
When detritus (nonliving organic matter such as dead plant material) breaks down it provides nitrogen that become ammonium
