APES Biogeochemical Cycles
Terms in this set (43)
cycle of matter between biotic and abiotic things in the environment involving biological, geologic and chemical interactions; they are driven by energy and gravity
During photosynthesis, plants remove carbon from the air and store it as chemical compounds such as sugar, the carbon will be released back into the atmosphere through cellular respiration. Sometimes plants or animals with carbon trapped in their body will get buried before fully decaying; over millions of years the heat and pressure will turn them into fossil fuels containing carbon. This carbon is then released back into the atmosphere through combustion.
Consists of five steps: nitrogen fixation, nitrification, assimilaton, ammonification, and denitrification.
First step of nitrogen cycle. The conversion of gaseous nitrogen to ammonia, a form that organisms can use. Nitrogen fixed bacteria (Rhizobium) is found in legumes, then this bacteria converts nitrogen gas to ammonia (NH3) and ammonium (NH4) (NOW USEABLE FORMS); can be done by lightning, combustion, volcanic activity and industrially
Second step of the nitrogen cycle. bacteria change ammonia (animal/plant waste) or ammonium into nitrate; the plants then absorb it First they turn it into nitrite, then oxidize it to form nitrate. (ammonia into poisonous nitrites (by bacteria) and then into nitrates)
3rd step of the nitrogen cycle. Plants absorb nitrate, ammonia, or ammonium and incorporate them into plant proteins. (nitrates into protein) animals eat the plants to make protein. it is used to make DNA, amino acids and proteins
4th step of the nitrogen cycle. conversion of animal wastes to ammonium; decomposer bacteria convert nitrogen containing organic compounds into simpler nitrogen containing inorganic compounds)
Final step of the nitrogen cycle. anaerobic bacteria changes nitrates back into nitrogen gas and returns to the atmosphere
A sedimentary cycle. Water erodes phosphorus-containing minerals and releases phosphorus into soil, where plant roots absorb it and incorporate it into biological molecules. Dead organisms decompose and release phosphorus back into the soil to be reused. Phosphate is often carried by water into the ocean where it remains on the sea floor for millions of years until uplift eventually exposes the sea floor sediments as new land surfaces, where the phosphate will be eroded again.
Most sulfur is underground in sedimentary rocks and minerals, which eventually erode and release sulfur compounds into the ocean. Many natural abiotic occurrences release sulfur into the atmosphere, where it combines with oxygen and hydrogen to form sulfuric acid. Plant roots absorb sulfate from soil and incorporate it into plant proteins. Dead organisms then release it back into the soil.
Water moves from the atmosphere to the land and ocean through precipitation. Water evaporates from the ocean, streams, soil, to form clouds in the atmosphere. Transpiration also adds water to the atmosphere. Plants and animals absorb or consume water, then decompose and release it back into the abiotic environment.
water from plants evaporates into the atmosphere as water vapor
returns water back to the atmosphere; faster when the temperature is hotter
downward movement of water through soil
passage of a liquid through spaces of material (soil)
water that flows on the earth's surface into other bodies of water; opposite of infiltration (lot of runoff.. low infiltration), rate of precipitation exceeds rate of infiltration, or the ground is saturated (pores are full)
gas into liquid; makes clouds; relative humidity must be saturated (100%) which means that air temperature must equal dew point and then condensation occurs when temperature goes below dew point; must stick to something to form which is called condensation nuclei, or dust particles
precipitation that does not infiltrate the ground or return to the atmosphere
water that sinks into the soil and is stored and renewed in underground reserves called aquifers
how do humans alter the hydrologic cycle
withdrawing large amounts of freshwater at rates that are faster than nature can accommodate (unsustainable), clearing vegetation because trees increase the amount of infiltration and transpiration, and increasing flooding when wetlands are drained; releasing pollutants into the water
store water (u shape)
abilities of water
water can shape and erode rocks, valleys are V shaped
properties of water
(due to hydrogen bonds between water molecules)
exists as a liquid over a range of temperatures (high specific heat), changes temperature slowly, has a high boiling point (100 C), melting point (0 C), in between 0 and 100 water is liquid, adhesion (water to other molecules), cohesion (water sticks to water), expands as it freezes, solvent, filter out harmful UV
what is carbon the basic building block of?
carbohydrates, lipids, proteins, and nucleic acids, it makes up organic material
how is carbon absorbed from the atmosphere?
through photosynthesis, plants release CO2.
how is carbon found in the ocean (a sink)
phytoplankton carry photosynthesis; carbon is found as carbonate and bicarbonate
how is carbon present in rock?
present in Limestone (a sedimentary rock)
how is carbon trapped?
can be sequestered in tree wood for 100s of years, an as fossil fuels for millions of years
CO2 + H20 together is carbonic acid and it lowers pH causing the shells of organisms to dissolve, produce H+ ions and release calcium
Sinks of Carbon
oceans (dissolved CO2 and living and nonliving shells), old growth forests (terrestrial biosphere stores most of the above ground soil and carbon), plant matter (photosynthesis), sedimentary deposits (limestone rock and carbon trapped in fossil fuels)
How is carbon released back into the atmosphere
1. cellular respiration (aerobic releases CO2 and anaerobic releases CH4) 2. Decay by decomposers 3. livestock produce CH4 when they digest 4. Burning fossil fuels 5. slash and burn forests 6. weatherization of rocks which breaks down CO2 and H2CO3 7. volcanic erruption 7. combustion 8. release of Co2 by warmer oceans
what does additional CO2 added to the atmosphere do?
tree clearing, burning of fossil fuels, and warms the atmosphere
nitrogen/ nitrogen sink
component of proteins, vitamins and nucleic acids/ atmosphere
how much of atmosphere does nitrogen gas make up
78%, N2 is very stable and unusable to living organisms, must be converted for use
human intervention in the nitrogen cycle
additional NO (nitric oxide) and N2O (nitrious oxide) in atmosphere from burning fossil fuels causes acid rain; N20 to atmosphere from bacteria acting on fertilizers and manure; destruction of forests, grasslands and wetlands; add excess nitrates to bodies of water; remove nitrogen from topsoil
why is phosphorus needed
ATP and nucleic acids
has no gas phase; Cycles through water, the earth's crust, and living organisms very slowly; Phosphate on land and in ocean sediment released by weathering (into ground and water) and is absorbed by plants and transferred to animals; limiting factor for plant growth on land bc soil doesnt have a lot of P and in marines bc it is not water soluble
sediments, terrestrial or bottom of ocean
how do we add phosphate
with phosphate based fertilizers in the soil, too many phosphates leads to an algae boom which will deplete O2
Impact of humans on Phosphorus cycle
1. Clearing forests, 2. Removing large amounts of phosphate from the earth to make fertilizers 3. Erosion leaches phosphates into streams
Sulfur why? where? how returns?
needed for amino acids and protein, found underground in rock (erodes into the ocean and soil and then plants take it in and it travels through the food chain)
human activities affect the sulfur cycle
burn sulfur containing coal leads to acid rain
how is sulfur found in the atmosphere
as a gas (from 1. sea spray (releases hydrogen sulfide and sulfur dioxide) 2. volcanic activity (sulfur dioxide) and conversion from bacteria); decomposers return sulfur to soil and sea