Hydrology & Biogeochemistry Exam 3 Review
Describe the sources of NOx/nitrate to rain and the implications of fixed nitrogen in rain.
****IMPLICATION: ACID RAIN CARS WITHOUT SCRUBBERS AND COAL POWER PLANTS CAUSE THIS*
Explain the difference between the "fast" and "slow" parts of the global phosphorus cycle.
-It is similar to the slow carbon cycle in that On the time scale of millions of years, these sediments are uplifted and returned to the surface, where weathering returns them to the active P cycle ******FAST:PLANTS LIVE & TAKE UP PHOSPHORUS FROM THE SOIL & THEN THEY DIE(WHICH HAPPENS QUICKLY) SLOW:THINGS THAT ARE LIVING IN THE OCEAN DIE & ARE PRESERVED AS MINERALS(APATITE) PEOPLE ARE MESSING WITH THE PHOSPHORUS CYCLE THROUGH MINING, WHICH CAUSES EUTROPHICATION******
Explain why increased N2O concentrations in the atmosphere have two negative impacts on the environment.
-N2O is a very powerful greenhouse gas, and traps heat in the troposphere -It is also one of the biggest ozone destructors, which means if the ozone layer is depleted harmful UV rays can reach the surface of the earth
Explain the Haber-Bosch process and its importance.
During World War I, two German scientists developed a way to make fertilizer from air The reaction consists of N2 + H2 under very high temperatures and pressure This discovery helped start the "Green Revolution", where agricultural yields increased dramatically and large-scale farming produced food for millions of people Energy intensive process Has created a glut of biologically-available N in the environment an industrial process for producing ammonia from nitrogen and hydrogen, using an iron catalyst at high temperature and pressure.
Describe the recent change in atmospheric nitrous oxide concentrations, and explain why this change is occurring.
However, human activities such as agriculture, fossil fuel combustion, wastewater management, and industrial processes are increasing the amount of N2O in the atmosphere. Nitrous oxide (N2O) emissions in the United States have increased by about 8% between 1990 and 2013. This increase in emissions is due in part to annual variation in agricultural soil emissions, and an increase in emissions from the electric power sector.
Describe how humans have altered the global nitrogen cycle and give some implications of these changes
Humans have greatly increased the amount of biologically-available N on the Earth -Fertilizer production is the biggest way people have changed the global N cycle Population growth (a side effect of fertilizer production) creates more human waste, which is very high in nitrogen Eutrophication and toxic algae blooms Nitrous oxide -Fossil fuels have organic N, and combustion leads to a buildup of inorganic N in the atmosphere Acid rain Nitrogen deposition Smog formation -Cultivation of nitrogen-fixing crops ****Haber-Bosch, legume cultivation & fossil-fuel burning*********
Describe the conditions leading to denitrification and where this process occurs.
In general, it occurs where oxygen, a more energetically favourable electron acceptor, is depleted, and bacteria respire nitrate as a substitute terminal electron acceptor. ***occurs when soils become waterlogged or Occurs in anoxic or hypoxic regions of the oceans or saturated terrestrial or lake environments soil organisms take oxygen from NO3-****
Explain the different types of N and P found in the environment.
JUST LOOKING FOR TYPES: NITROGEN: (INORGANIC) NH4, NO2,NO3-,N2O(NITROUS OXIDE),N2,NH2OH ORGANIC WOULD BE AMINO ACIDS PLANTS USE AMMONIUM(INORGANIC) IF NOT TAKEN BY A PLANT, IT WASHES AWAY AS NITRATE(NO3-),WHICH IS THE MOST ABUNDANT IN WATERWAYS NITRIFICATION IS FROM AMMONIUM TO NITRATE DENITRIFICATION IS NO3- TO N2 NITROGEN FIXATION IS NITROGEN TO AMMONIUM *********Atmospheric N2 Inorganic N - not bound to organic C NO3-, NO2-, NH4+ This is what plants use - these are the main components of fertilizers Organic N: Amino acids and proteins***** PHOSPHORUS IS INORGANIC PHOSPHATE;PO4-
Explain what controls the geographical deposition of dissolved nitrate in rain.
LOOK AT THE MAP( IT IS BECAUSE THE AREAS WITH THE HIGHEST AMOUNT OF COAL POWER PLANTS WITHOUT SCRUBBERS HAVE THE HIGHEST AMOUNTS OF DISSOLVED NITRATE IN RAIN) ALSO COMES FROM CARS WITHOUT SCRUBBERS *CARS WITHOUT SCRUBBERS & COAL POWER PLANTS WITHOUT SCRUBBERS, THE MIDWEST HAS THE HIGHEST CONCENTRATION, AND THIS CAUSES ACID RAIN
Draw the global phosphorus cycle, including all of the important reservoirs and fluxes, and an indication of the magnitude of each.
Largest reservoir of P on earth is ocean sediments and rocks,plants & soils dissolved in the ocean waters is the second *****Largest flux is in internal cycling within sediments, rivers******* high phosphorus cycle small flux in dust & sea spray, but doesn't really matter *****Humans have influenced the global P cycle through mining****
Draw the global nitrogen cycle, including all of the important reservoirs & fluxes, and an indication of the magnitude of each.
Major reservoirs of N: Atmosphere (>>> 99% of all N on Earth) Oceans Soils and plants Rocks Major fluxes of N: Nitrogen fixation Denitrification Nitrification Decomposition of organic matter Fossil fuel combustion THE GLOBAL NITROGEN CYCLE IS A BALANCE BETWEEN DENITRIFICATION AND NITROGEN FIXATION
Explain why N and P are needed for life on Earth.
Nitrogen is in proteins, which serve many different biological functions Phosphorus is in ATP; coenzyme used as an energy carrier in the cells of all known organisms; the process in which energy is moved throughout the cell
Explain the similarities and differences between the cycles of N and P and the global carbon and water cycles.
Nitrogen: Similarities to the carbon and water cycles: Nitrogen molecules are cycled around the globe through various reservoirs via a series of fluxes Nitrogen exists in organic and inorganic forms: only plants can use inorganic N, and other living things rely on plants as the ultimate source of N in food (exactly like C) Also like the carbon cycle: humans have greatly altered the nitrogen cycle Finally: like the carbon cycle, it is hard for most living things on Earth to get nitrogen from the atmosphere Phosphorus: On the time scale of millions of years, these sediments are uplifted and returned to the surface, where weathering returns them to the active P cycle This is similar to the C cycle, which also has fast and slow aspects The phosphorus cycle is different compared to the water,carbon, and nitrogen cycle because it can not be found in the gas state. Phosphorus is only found in land, water, and sediment. The phosphorus cycle is a bio-geochemical cycle that describes the movement of phosphorus through the lithosphere, hydrosphere, and biosphere. The other cycles is the process by which it is converted between its various chemical form. Phosphorus has small particles that only sometime go up into the atmosphere and contribute to acid rain but other than that phosphorus stays in and on land, sea, and sediment. ******PLANTS TAKE UP INORGANIC N & P AND CONVERT IT TO ORGANIC, THE BIGGEST DIFFERENCE IS THAT PHOSPHORUS ISN'T PRESENT IN THE ATMOSPHERE, WE CANNOT MAKE IT, WE CAN ONLY GET IT FROM ROCKS THROUGH MINING*****
Explain why phosphorus fertilizers can cause algae blooms in lakes and explain why the spring bloom in Lake Eerie was the largest on record, despite decreases in phosphorus fertilizer used by farmers.
The process by which a body of water acquires a high concentration of nutrients, especially phosphates and nitrates. These typically promote excessive growth of algae. As the algae die and decompose, high levels of organic matter and the decomposing organisms deplete the water of available oxygen, causing the death of other organisms, such as fish. Even though usage of fertilizers has decreased, algae blooms are increasing because of global warming. The increase of storms in the spring & spring coming earlier means that when the farmers use the fertilizer in the spring it runs off into the lake very quickly because of the rain. *MORE INTENSE RAINFALL PUSHED THE FERTILIZER INTO THE RIVER*
Explain the processes of denitrification and nitrogen fixation, and how these processes work.
denitrification: The process by which microbes convert inorganic N to N2. This process can help alleviate some of the effects of eutrophication However, nitrous oxide (N2O) is a byproduct of this reaction. An increase in global denitrification rates is a main source of N2O emissions. Lowers the amount of nitrogen available to an ecosystem and replenishes the atmosphere. nitrogen fixation: a process in which nitrogen (N2) in the atmosphere is converted into ammonia (NH3). Nitrogen fixation, natural and synthetic, is essential for all forms of life because nitrogen is required to biosynthesize basic building blocks of plants, animals and other life forms, e.g., nucleotides for DNA and RNA and amino acids for proteins. Therefore, as part of the nitrogen cycle, it is essential for agriculture and the manufacture of fertilizer.
