Lectures 13-15 + TBL 4 Flashcards
1
Q
Where change occurs
A
Boundary conditions
2
Q
Equilibrium where species on both sides contribute equally. On either side, one species dominates over others
A
Boundary line
3
Q
limits set by the environment
A
practical limits
4
Q
In acidic, low pe waters, _____ is the predominant species
A
Fe2+
5
Q
In acidic high pe waters, _____ is the predominant species
A
Fe3+
6
Q
In basic, low pe waters, _____ is the predominant species
A
Fe(OH)2
7
Q
In basic, high pe waters, ______ is the predominant species
A
Fe(OH)3
8
Q
Under natural aquatic conditions, the two predominant forms of Fe are
A
Fe2+, Fe(OH)3
9
Q
In anoxic conditions water holds ______ Fe in solution as ______
A
more, Fe2+
10
Q
Fe(s) is only stable at pe = ______, which is not possible in H2O, Fe is thus _____/_____ even in reducing conditions
A
-9.95, oxidized, corroded
11
Q
Generally oxidation / dissolution - destructive alteration of metal through interaction with its surroundings
A
Corrosion
12
Q
_____ can accelerate the corrosion process, or in some cases slow it by forming protective ____ films. ______ environments generally slow the process but do not stop it
A
oxygen, oxide, reducing
13
Q
Most commonly used metals are ______ under typical environmental conditions, as they can form _____, _____, _____, and _____
A
unstable, ions, salts, hydroxides, oxides
14
Q
Unicellular organisms with no nucleus
A
bacteria
15
Q
unicellular organisms with a nucleus
A
protozoa
16
Q
photosynthetic, multicellular organisms that contain chlorophyll
A
algae
17
Q
Organisms that convert inorganic compounds to organic compounds and vis versa, and catalyze many chemical processes in water and sediments
A
micro-organisms
18
Q
organisms that break down the complexity of organic matter into simple compounds and get energy from organic matter
A
reducers (bacteria, fungi)
19
Q
organisms that create organic matter from simple compounds using an independent energy source (such as sunlight or chemical energy source)
A
producers (some bacteria, algae)
20
Q
bacteria that require O2 as an electron acceptor
A
aerobic
21
Q
bacteria the function only in the absence of O2
A
anaerobic
22
Q
Bacteria that can use either O2 or another electron acceptor depending on the environment
A
facultative
23
Q
the phase of bacterial growth in which the population doubles over the regular time interval
A
log phase / generation time
24
Q
The life cycle of bacteria cells ends when a limiting factor such as _____, _____ or _____ is encountered
A
depletion of nutrients/food source, build up of toxins, exhaustion of O2 (or other oxidant)
25
growth rate of bacteria is _____ dependent, and the optimum is different for different bacteria
temperature
26
oxidation of organic matter by oxygen
aerobic respiration
27
oxidation of organic matter by oxygen yields ______kcal of energy, which is used for _____, _____, ____, and _____
29.9, metabolism, reproduction, locomotion, synthesis of new cell material
28
Energy yields, per unit organic matter, decrease in the following order:
O2, NO3, MnO2, FeOOH, SO4, CO2
29
Bacteria can _____ other bacteria by living in their optimal environment based on which _____ give them more energy
outcompete, oxidants
30
The conversion from NO3 to N2
denitrification
31
The conversion from NO3 to NH4+ (usually does not occur until all oxygen is depleted)
nitrate reduction
32
The conversion from MnO2 to Mn2+
manganese reduction
33
the conversion from FeOOH to Fe2+
iron reduction
34
the conversion from SO4 to HS-
sulphate reduction
35
the conversion from CO2 to CH4
methanogenesis
36
Methanogenesis only yields ______ of the energy available using oxygen. _____ is the oxidant, but more of it is ____ than _______, thus it never runs out. The bacteria involved cannot tolerate any ____
20%, CO2, produced, consumed, O2
37
a redox process in which both oxidizing and reducing agents are organic
fermentation reaction
38
When O2 is present, ____ is produced from organic matter, when O2 is exhausted, it is used next, but runs out quickly in most environments. When NO3 is exhausted, _____ and _____ act as oxidants, but are not very abundant in waters due to being ____. However, they are abundant in ______. When these are exhausted, ______ begins oxidizing (seawater), after which _______ begin oxidizing
NO3, MnO2, FeOOH, solids, sediments, SO4, CO2
39
The conversion of organic matter to CH4; used in biological waste treatment to reduce BOD
Anaerobic respiration
40
methane can be ______ (transferred to the atmosphere), in which it ______ further to ______, removing the organic matter
degassed, oxidizes, CO2
41
organic matter contributes to ______. However, production of 1 mole of _____ removes 2 moles of organic matter, preventing 2 moles of ____ being used to break down organic carbon in water, CO2 is then tapped as a _____ ___ in some cases
BOD, CH4, O2, fuel source
42
Water trapped in sediments
pore waters
43
Sediments gradually accumulate on the top, so deeper in the sediments, organic matter has had _____ time to degrade.
more
44
in oxidizing conditions, _____, _____ and _____ are common
oxides, hydroxides, carbonates
45
In reducing conditions _____ and sometimes ____ are common
sulphides, carbonates
46
_____ are much less soluble than ______
sulphides, sulphates
47
In reducing conditions, ______ reduce _____ to ______, causing ________ of metal _____
microorganisms, sulphates, sulphides, precipitation, sulphides
48
In oxidizing conditions, ______ re-oxidizes sulphides to sulphates, and thereby releases _____ to solution
aeration, heavy metals
49
The most common trace metal held in sediments are
Cadmium, copper, iron, mercury, manganese, nickel, lead, zinc, etc.
50
Sulphur is most common in oxic water as ______, which floats freely and does not bind. Its reduced state, _____, is found in organic matter, bound to metals and _____. In reducing environments, _____ and/or ______ is produced by bacteria
SO4 (sulphate), S2-, protons. H2S, HS- (sulphide)
51
_____ is a water hazard (____) and produces _____ upon oxidation, which is a major source of atmospheric ____ and acid _____
H2S, toxic, acid, sulphur, rain
52
harbours are ____ periodically to remove sediment build up. This causes ________ sediments to be exposed to oxidizing conditions, which leads to oxidation of _____ and ____ _____
dredged, reducing, sulphides, metal release
53
The conversion of organic N to NH4+ performed by all organisms (respiration) in all environments, to get energy out of organic matter
ammonification
54
the conversion of NH+ to NO2 to NO3; the process of oxidizing ammonia to nitrate. Occurs in the presence of oxygen; by bacteria that use the resulting chemical potential energy; usually in deep waters
nitrification
55
The conversion of NO3 to NO2 to NH4+ to organic N by plants - phototrophs in sunlit regions for body mass (amino acids, proteins, etc.)
nitrate assimilation
56
The conversion of NH4+ to organic N
ammonia assimilation
57
The conversion of NO3 to NO2 to N2 by bacteria in suboxic or anoxic, using nitrate as an oxidant to break down organic matter (aerobic respiration)
denitrification
58
Conversion of N2 to NH4+ to organic N; by cyanobacteria and other bacteria in surface waters and soils to bring N back into the cycle for uptake by phytoplankton
nitrogen fixation
59
microbial processes by which N in nitrate is reduced to a lower oxidation state (NO3 -> NO2/N2/NH4+/Org-N
nitrate reduction
60
Any organism utilizing NO3 for ____ ___ must first reduce the N to the ____ oxidation state
protein synthesis, -3
61
NO3 is a good ____ in a low O2 environment, but usually runs out fast. _____ requires energy, but is necessary to build _____ and ______.
oxidant, nitrate assimilation, proteins, amino acids
62
In solution, _____ is a stable species in the presence of ______. However, the process of nitrification is _____ even though it is favorable. Thus it is ____ by bacteria. ______ for terrestrial crop plants usually use ______, which microbes transform to _____
NO3, oxygen, slow, catalyzed, fertilizer, NH4+, NO3
63
in sewage sludge, bacteria use ______ produced by _______ as an oxidant and produce _____ (denitrification) which degasses
NO3, nitrification, N2
64
the conversion of ammonia to nitrite
nitrosmonos
65
the conversion of nitrite to nitrate
nitrobacter
66
both nitrobacter and nitrosmonos are ______ and require ___. They also both have a high energy yield of ______
bacteria, oxygen, 10kcal
67
nitrogen fixation does not occur easily due to the ______ in N2 that results in high ___ energy, and a _____ slow reaction. This is why N2 is a ______ gas. This reaction is common in _______ especially associated with the roots of ________ (root nodules), rare in _______ because it requires a lot of ______, and is a complex process
triple bond, activation, kinetically, unreactive, soils, legumes, water, iron
68
At mid pH, levels, ____ is stable at high pe, ____ is stable at mid pe, and _____ is stable at low pe
NO3, NO2, NH4+
69
The process of organisms taking up nitrate, nitrite or ammonium and incorporating N into organic matter
assimilation
70
When sulfide ores are exposed to oxygen in air or oxic waters, S is ______, H+ _______, and [M] _______
oxidized, increases, increases
71
A mix of sulphuric acid and high concentration of metals produced by oxidation of sulfide minerals catalyzed by bacteria
acid rock drainage
72
acid rock drainage releases high concentrations of toxic metals such as
Fe2+, Cu2+, Zn2+, etc
73
First step in acid rock drainage formation
Oxidation of S in pyrite or other metals which produces H2SO4
74
Second step in acid rock drainage formation
oxidation of Fe2+ to Fe3+
75
Third step in acid rock drainage formation
Further dissolution of FeS2 by Fe3+ (more H2SO4 production)
76
Fourth step in acid rock drainage formation
If pH is >3 after mixing out into the environment, Fe(OH)3 precipitate forms (yellowboy deposits)
77
To stop the oxidation of sulphide ores, the exposed areas are covered with _______/______ which suck up various ______ preventing them from reaching the ore and contact with the environment. You can also block the ____ to prevent water flow through the mine interior
soil/peat, oxidants, exits
78
partially decayed vegetation - organic rich material
peat
79
a mixture of Ca(OH)2 and water used to neutralize acid formed in ARD
lime slurry
80
In order to neutralize the acid, you can actively use ______ to absorb the H+ in a controlled treatment facility. Alternatively, you can use ________ rocks (limestone), to absorb H+ (add alkalinity), but ______ may form on the carbonate which slows the dissolution. This method may be more effective in an _____ environment, where Fe stays ______, and has less of a tendency to be ______ up to a higher pH
Ca(OH)2, Calcium carbonate, yellowboy, anoxic, Fe2+, hydroxo
81
In order to remove metals from ARD, you can actively -_______ metals or ______ with other metal _______ such as Fe(OH)3 in an active treatment facility. Other methods include using ______ to complex and _____/______ metals from water leaving the system, creating aerobic _______, where metals precipitate as ______ or absorb to freshly precipitated hydroxides such as Fe(OH)3. You can also create _____ wetlands to re-precipitate metals as ______, which must stay anaerobic. Usually a combination is more effective for passive treatment
precipitate, co-precipitate, hydroxides, peat, immobilize/remove, wetlands, hydroxides, anaerobic, sulphides
82
In the Britannia mine, precipitation into open _____ and underground _____ and shafts, where _____ mineralization occurred formed ______
pits, mines, sulphide, acid mine drainage
83
small 2200 portal
Jane creek -> Britannia Creek, -> Howe sound surface
84
large 4100 portal
Howe sound at depth
85
Howe sound became toxic to fish because of contamination from ______ and ______, ______, _____, and mine tailings
contaminated fill, waste rock, drainage, groundwater
86
To treat Britannia, the 2200 portal was ______, the ARD was treated with a ________, which then precipitated as _______, then a customized _____ was added to increase aggregation of ______. The "clumps" of precipitate were then collected and used as part of the fill for the _____ pit of the mine. _______ _____ _____ were re-routed away from the underground mine workings, and _____ assessments were anticipated for contaminated sediments at certain locations at the site
plugged, lime slurry, iron hydroxide, polymer, colloids, open, uncontaminated surface waters
87
The iron hydroxides are safe to use as fill for the open put because it is already _____, so exposure to air will not cause the metals to _____. It would mobilize if ______
oxidized, mobilize, reduced
88
A mine in BC in which the ARD was collected in a retention pond which breached and drained mine halings into a nearby lake
mount polley
89
Sulfuric acid is directly _____ and can cause excessive ______
toxic, minerals that it contacts
90
Bacteria can oxidize ____ to sulphate when there's oxygen. Because of high concentration of sulphate in ______, formation of this compound causes ____ problems in coastal areas and is a major source of _________ sulfur.
H2S, seawater, pollution, atmospheric
91
____ can form in the presence of sulphide, leading to a black sediment
FeS
92
When elemental sulfur is added excessively to _____ soils, the acidity is increased because of a microorganism mediated reaction, which produces ________
alkaline, sulphuric acid
93
Elemental sulphur may be deposited as _____ in the cells of purple/_______ _______
granules, colorless, bacteria
94
In the presence of oxygen, some bacteria can oxidize ____ to ____
H2S, SO4
95
Bacteria can reduce inorganic ______ to H2S. In doing so, they use it as an electron acceptor in the oxidation of ______. The process requires multiple bacteria
SO4, organic matter
96
Reducing NO3 to ____ yields the most energy (almost the same as O2) however, some organisms specialize in only taking this reaction partway
N2
97
_______ usually happen in the ____ waters. Thus nitrate reduction occurs in mostly ____, ____ , but also ____ environments
nitrate assimilation, surface, suboxic, anoxic, oxic
98
_______ is the most abundant form of N, but is often unavailable. _____ is the most abundant form that is available to organisms
N2, NO3
99
Often terrestrial crop plants cannot take up _____, and need ______ to take up NO3
NH4+, nitrification
100
nitrogen fixation occurring in soils often _____ into streams but are not accessible in _______, where it is more rare due to needing a lot of insoluble ______, ____ and a ____ environment
run-off, oceans, Fe, photoautotrophs, sunny
101
At a high pe, _____ is dominant across all _____, because HNO3 is a strong acid. There is a lot less _______, and some ______.
NO3, pH, NO2, HNO2
102
Including _____, it becomes the dominant form and ______ disappears. In the atmosphere where there is a lot of ______ present, _____ oxidizes to ______. Thus, the atmosphere is often not in ______, due to life and the kinetic ____ of N2
N2, NO2, O2, N2, NO3, equilibrium, stability
