Biogeochemical Cycles Flashcards

Question

Give some solar power stats

Answer 1

- 4.9% UK's total energy gen - most widely used alternative energy source worldwide - solar energy extracted using PV cells - used for light and heat e.g. solar water heating

Answer 2

- cells made from silicon material which absorbs light, causing electrons to move - generates a DC - each PV cell = small, so they are mounted into a module which is further grouped with other modules into an array - the power generated is used to charge cells or inverters and then onwards to power common electrical appliances

Answer 3

solar panels used to trap energy then water circulating within the panels is warmed - panels painted black to absorb heat in order to obtain the maximum energy from the sun - using the hot water produced can reduce energy usage and elec bills

Answer 4

biological molecules: - amino acids (protein building blocks) - structure of DNA (nucleic acid base)

Answer 5

a) nitrogen gas (N2) oxides of nitrogen (NOx) b) dissolved nitrates and ammonium ions c) Soil: ammonium compounds, nitrites, nitrates Rocks: minerals containing nitrogen d) Living orgs: DNA, proteins (cell membrane, hormones, enzymes) Dead organic matter: proteins, which release ammonium compounds as they decompose

Answer 6

Fixation Ammonification Nitrification Denitrification Ionisation Decomposition Food chains Leaching Root absorption

Answer 7

most orgs cannot use this form because N has is inert so does not readily undergo chem reactions

Answer 8

must incorporate nitrogen in 'fixed compounds' e.g. nitrate ions, ammonia or ammonium

Answer 9

from digest, absorb and assimilate forms of nitrogen from their food and pass it up the food chain e.g. from plants or other animals that have eaten plants

Answer 10

where processes from ionising phenomena (e.g. lightning and meteor trails) provide the energy to break the N triple bond, allowing it to react and produce oxides of nitrogen

Answer 11

where some microorganisms can chemically reduce nitrogen to compounds such as ammonia - N taken out of atmosphere and stored in the ground e.g. lightning and root nodules of leguminous plants

Answer 12

LEGUMES: have N-fixing bacteria called rhizobium that form a symbiotic relationship with root nodules. They convert N gas into ammonia that undergoes nitrification into nitrites then nitrates that plants use to make proteins e.g. peas, beans, clover

Answer 13

free living in soils - AZOTOBACTER

Answer 14

- contains an enzyme called nitrogenase - converts N and H to ammonia - used to make AA which the legume can then use to make proteins in return for supplying the bacteria with carbohydrates

Answer 15

Where some free living bacteria and fungi break down animal and plant proteins with the nitrogenous waste released into the soil as a form of ammonium

Answer 16

1. proteins made by plants enter and pass through food chain 2. at each trophic level, metabolism produces organic nitrogen compounds that return to the env mainly in excretions 3. the final beneficiaries of these materials are microorganisms of decay which break down the molecules in excretions and dead organisms into ammonia, a form of ammonium basically: root absorption, food chain, excretions, decomposition

Answer 17

oxidation of ammonium ions to nitrites, then nitrates, by nitrifying bacteria in the soil (free living and aerobic)

Answer 18

Nitrosomonas convert ammonium to nitrites Nitrobacter convert nitrites to nitrates BASICALLY: ammonium, bacteria, nitrites, nitrates, roots

Answer 19

the chemical reduction of nitrates in soil into nitrogen and NOx gases, by anaerobic denitrifying bacteria, decreasing soil fertility

Answer 20

denitrifying bacteria in soil or anaerobic aquatic sediments e.g. pseudomonas use nitrates as an alternative to oxygen for the final electron acceptor in their respiration when they convert the nitrate back into nitrogen gas, it then gets released into the atmosphere

Answer 21

where nitrogen passes between organisms as amino acids and proteins in food

Answer 22

soluble ions such as nitrates and ammonium compounds are taken into plant roots

Answer 23

loss of soluble ions such as nitrates from the surface layers of the soil as it is carried away by water - often carried into water bodies, where it acts as nutrients for aquatic plants and algae - EUTROPHICATION

Answer 24

fixation, decomposition, nitrification - remove N from atmos, pass it through ecosystems denitrification - reduces nitrates to N gas, thus replenishing atmos, closing the N cycle

Answer 25

Where amino groups in proteins are released as ammonium ions by the actions of bacteria, fungi and detritivores as they decompose dead organic matter

Answer 26

The Haber process Agriculture Pollution/ff emissions

Answer 27

- making ammonia from N and H using iron catalyst at high temp and pressure - artificial fixation of N to ammonia requires loads of energy - ff=unsustainable - ammonia can then be converted to nitrates - main purpose is for fertilisers - more N out of atmosphere, more N in soil

Answer 28

combines N from air with H derived from mainly natural gas (methane) into ammonia equal volumes of gas contains equal numbers of molecules N2+3H2 = 2NH3 - N2 and H2 are fed in - compressor @ 200 atm - reaction: iron catalyst @ 450 degrees - cooling chamber: NH3 is cooled to liquify the gas and unreacted N2 and H2 are cycled back into the compressor

Answer 29

- nitrate fertiliser use increases leaching and eutrophication problems if applied near a river or before heavy rain - draining fields makes soil conditions aerobic so there are more nitrifying bacteria, so less N in the atmos due to decreased denitrification - ploughing = soil disturbance = increased rate of decomposition of dead organic matter which releases more NOx into the atmos - leguminous plants (peas, beans, clover) may be grown to increase soil nitrogen compound level which other crops can then absorb = less N in atmos

Answer 30

- NOx released into the atmos by combustion, produces acid rain (nitric acids) that affects pH of soils and solubility of N. Some ecosystems need low N content to survive and excess nitrates can lower the species diversity - acid rain increases the quantity of nitrates washed into the soils by rain (plus leaching)

Answer 31

1. MOBILE: can be transported long distances on prevailing winds 2. SMOG: ground level ozone from NOx and Volatile Organic Compounds (VOCs) - damage to lungs, veg, crops 3. ACID RAIN: damages forests, buildings, water sources 4. VISIBILITY: Nitrates and Nitrites block light and reduce visibility (e.g. increased car crashes) 5. GLOBAL WARMING: N2O (nitrous oxide)= 300x more damaging than CO2 6. PARTICLES: NOx reacts to form acid vapour and particles, penetrates lungs = emphysema, bronchitis, respiratory disease

Answer 32

- increased rapid algal growth in water bodies due to increased nutrient levels - biological waste may be washed into water bodies or dumped there - ammonium compounds converted to nitrites and nitrates which cause the algal growth

Answer 33

1. nutrients wash in 2. rapid growth and proliferation of algae and phytoplankton 3. block light so plants cannot photosynthesise (but the algae can be a food source) 4. decompose: produce lots of CO2 leading to acidification, which lowers pH 5. the decomposers decomposing them use lots of O2 so there is a drop in O2 6. plants and animals die of hypoxia (lack of oxygen)

Answer 34

Control of combustion processes Control of NOx releases Management of biological wastes Organic fertilisers Management of soil processes

Answer 35

a) NH3 b) NH4+ c) NO2- d) NO3- e) N2O f) NOx

Answer 36

- 800% increase in nitrogen fertiliser use from 1960-2000 - human activities contribute to twice as much terrestrial N fixation as natural sources and provides about 45% of the total biological useful N produced annually on Earth - 1/4 all global food produced is wasted along the supply chain - excessive use of nitrogen fertilisers for food that's never eaten - as a component of fertiliser, N helps feed around 1/2 world's pop - N fertiliser prices rising, threats to food security - NOx = 300x warming potential of CO2

Answer 37

We need to balance food production with reducing CC. NOx emissions = 300x warming potential of CO2 but we need fertilisers to beat food insecurity

Answer 38

BIOLOGICAL FUNCTIONS: component of bones, DNA, RNA, cell membrane, proteins

Answer 39

most P compounds have low solubility and there is no P gaseous reserve, meaning it is not biologically available

Answer 40

solid (particulate) P in Earth's crust/phosphate rocks (sedimentary rocks) and deep sea sediments

Answer 41

phosphate ions (PO4 3-) aka orthophosphate - inorganic and biologically available to plants

Answer 42

1. phosphate compounds found in sed. rocks 2. rocks weathers - phosphorus slowly leaches into surface water/soils 3. phosphate compounds in soils taken up by plant roots. P conc in soil = low, so plants develop symbiotic relationships with mycorrhizal fungi which extend hyphae into soil to enhance P uptake 4. animals eat plants, get the P 5. When plants/animals excrete/die, P taken up by detritivores (e.g. beetles, earthworms) and returns to the soil 6. P compounds may also be carried in surface runoff to rivers, lakes, oceans. P = not very soluble in water, so binds tightly to molecules in soils and reaches water by travelling in runoff with eroded soil particles 7. P compounds from water bodies/bio wastes of marine orgs sink to sea floor, forming sedimentary layers 8. over long periods of time, P-containing sedimentary rock is uplifted to the land. Process very slow: average phosphate ion has oceanic residence time of 20,000-100,000 years

Answer 43

the amount released by rock is a very small fraction of the amount stored in biomass

Answer 44

phosphorus compounds in marine organisms are locked into the rock when dead organisms/waste sink to the sea floor then compact and cement into rock, then eventually gets uplifted into mountains, weathered, and the cycle starts again

Answer 45

a) apatite, a type of calcium phosphate b) remains of aquatic organisms c) limestone, marble, mudstone

Answer 46

- P compounds have low solubility - no gaseous reserves/cycle - sedimentation and erosion takes longer - amount of P released by rocks is a very small fraction of the amount stored in biomass

Answer 47

a) phosphorus fertilisers (e.g. ammonium phosphate) b) because before apatite was mined, they strip mined guano deposits at the surface e.g. Nauru in Pacific Ocean (one of first sites) but now most large guano deposits have been fully exploited c) because rock takes thousands of years to form so we are exploiting it faster than it replenishes and we will eventually run out

Answer 48

- deforestation e.g. rainforest - fertiliser use and agricultural run off - mining of phosphate rocks

Answer 49

- rainforest ecosystems are supported through recycling of nutrients, with little/no nutrient reserves in soil - as forest cut/burned (mainly for agriculture) nutrients originally stored in plants/rocks are quickly washed away by heavy rain, making the land unproductive, so more and more is chopped. Vicious cycle - no roots means soil erosion, and also no assimilation so less P is available for the cycle - recovery is affected by P availability in soil, if there is rapid rates of soil loss (e.g. wind and water erosion) it may prevent complete ecosystem recovery

Answer 50

- fertilisers mobilises P compounds into the env in more soluble forms, increasing crop production but also run off and eutrophication - crops cannot absorb all fertiliser in soil, which leads to increases phosphate levels in waterways, excessive growth of algae, and eutrophication - algae produce toxic compounds, and when they die, their decomp by decomps uses O2 which causes hypoxia for other aquatic orgs (see eutroph flashcard)

Answer 51

most phosphorus mined as apatite (calcium phosphate) then treated to produce ammonium phosphate which is more soluble, and the full exploitation of guano deposits means more and more rock is mined

Answer 52

- root absorption/assimilation - decomposition - sedimentation - mountain building and weathering

Answer 53

- plant roots absorb the phosphates they will use in metabolic processes - not effective at absorbing phosphates as there is a low P conc in the soils, so forms symbiotic relationship with mycorrhizal fungi - MF have extensive fungal networks of hyphae in the soil with increases SA for absorption

Answer 54

The breakdown of phosphorylated proteins in dead org matter releases phosphates that are often made more soluble by soil microbes so they can be absorbed by plants. Alternatively, they get washed into waterways

Answer 55

- where the P in sediments and particles settle on the seabed - P in orgs that die and become incorporated into sediments may no longer be available to other orgs e.g. plankton dies, sinks to sea floor. This reduces productivity of surface waters of oceans because P availability is often a limiting factor

Answer 56

- where continental drift and uplift forms new mountain ranges and breakdown of rocks in situ (weathering) releases phosphates - processes that mobilise phosphates and make it available to living orgs are often slow, so the P in marine sediments may not become available until the processes above happen

Answer 57

1. Selective breeding/genetic engineering of crops 2. improved farming practises 3. biological fertilisers

Answer 58

- some plants have evolved to adapt to P shortage: by identifying the genes associated with phosphorus efficiency (PE) it informs the development of engineering strategies in improved PE in P limited soils - engineer root symbiosis with mycorrhizal fungi for inorganic phosphate (Pi) acquisition, or enhance Pi uptake per root length (increases efficiency of P absorption by crops)

Answer 59

- Riparian buffers - Subsurface injection - Timing of fertiliser application - Right amount of fertiliser application

Answer 60

- vegetated areas next to waterways that protect water quality, flood control, erosion and wildlife - they trap particulate nutrients and takes up some P, reducing runoff: reduced eutrophication, makes more P organically available, reduces need for more fertiliser

Answer 61

- injecting fertiliser/manure below the surface reduces runoff because it can go straight to the roots

Answer 62

- maximises uptake - reduces runoff - reduces leaching - reduces gaseous losses

Answer 63

- by testing the soil, plants and manure to determine the optimum fertiliser amount, it minimises the excess that will be runoff or get leached and reduces the amount needed to be mined

Answer 64

- it maintains P nutrient availability without needing more to be mined, and more can be recycled quicker and more efficiently

Biogeochemical Cycles Flashcards

(90 cards)