Midterm Flashcards
(216 cards)
0
Q
Distinguish between lotic and lentic fresh water
A
Lotic - running water
Lentic - standing
1
Q
Describe the water composition of the earth
A
Oceans - 97.2%
Ice and glaciers - 2.1% and declining
Surface water <0.02% of that
2
Q
What are the two different rock types that Manitoban lakes are on
A
Limestone
Precambrian shield rock
3
Q
What is the primary difference between limestone lakes and precambrian shield lakes
A
Precambrian shield lakes are super unproductive. The rock is solid so there are very few dissolved and fewer nutrients solids in those lakes. Things like acid rain can seriously fuck up a lake with no buffer system.
Limestone lakes are more productive with a lot of dissolved solids, so they can take more abuse (pollution and pH change)
4
Q
Do dissolved substances increase or decrease the density of water?
A
Increase
5
Q
What are the factors that affect density of water?
A
Temperature, pressure, dissolved solids,
6
Q
The highest density of water is found at ______ degrees Celcius
A
3.4
7
Q
Does freezing point go up or down the more dissolved materials there are?
A
Down
8
Q
The higher the temperature, the _______ the density change from one degree to the next
A
Greater
9
Q
How does density of water effect freshwater fish.
A
Fish are exposed to more moderate temperature differences throughout the year - with ice only floating on top instead of sinking to the bottom
10
Q
The viscosity of water is ____x that of air at the same temperature
A
100x
11
Q
Surface tension ______ with increasing temperature
A
Decreases
12
Q
What external factors affect surface tension and why is that important?
A
Electrolytes raise surface tension and pollutants (like acids) lower it.
This important because many animals use the surface tension of standing water to walk or lay eggs
13
Q
What is the nm range for solar radiation
A
150-3200
14
Q
What is PAR?
A
Photosynthetally active radiation - the radiation that can be used by photosynthetic organisms (400-700nm).
Some organisms can photosynthesize out of this range but have special processes to do so
15
Q
Differentiate between the photic zones of Shoal lake and West Hawk lake
A
Shoal lake - shallow so photic zone extends to bottom
West hawk lake - deep so photic zone is only top few feet
16
Q
Why do aquatic macrophytes have a shorter photoperiod than terrestrial ones?
A
Because when the sun is setting it is as such an extreme angle that almost all light is reflected.
17
Q
Light over ____nm long does not travel far in water
A
900
18
Q
What happens to light when it hits water?
A
Some light absorbed, some refracted, some continues downward. Light attenuation varies throughout the water column because of the presence of floating substances and algae
19
Q
Light attenuation is ______ in DISTILLED water
A
Exponential
20
Q
What types of lakes are the most clear (highest light attenuation)?
A
Alpine and crater lakes
21
Q
Why do deep water algae appear red?
A
Red light disappears from the water column first so there is not point in trying to absorb it - instead it is reflected and causes colour
22
Q
What is K= ln Io - ln Iz/Z
A
Beer-Bouqer law
23
Q
What is the compensation point?
A
Point at which respiration = photosynthesis, life barely possible
24
Why is it better for water to freeze when it is calm?
Because then light can more easily penetrate the ice. If water is flowing when it freezes the ice is "frazzled" and not much light penetrates
25
Brown peat and bog waters are caused by ______ acids
Humonlimnic
26
What colour are limestone lakes?
Turqoise/aquamarine
27
Distinguish between apparent and true colour
Apparent - the way it appears to the eye
| True - measured via spectrophotometry of DISTILLED wate
28
Organisms living in a narrow range of cold temperatures are called _______
Cold stenothermic
29
Organisms that can readily adapt to temperature change are called
Eurythermic
30
_______ organisms can only exist at high temperatures
Polythermic
31
What is a graben lake?
Graben occurs when tectonic shift causes large chunk of earth to fall downwards. This creates a basin. This basin fills with water.
These lakes are very deep with rapidly sloping sides, usually too deep for macrophytes, can be elongated, sometimes have almost perfectly flat bottoms
32
What are volcanic lakes?
Top blows off volcano and water collects
33
What is a coulee lake?
Occurs when Laval flows through water basins and cools to form a dam
34
List the types of glacial lakes (you know this shit)
Moraine-dammed lakes
Kettle lakes
Basins formed by scouring - land depressed so much that ice just collected there (this is how Great Lakes were formed)
35
What is karst topography and where does it occur?
Caves.
| Occur in areas with limestone bedrock
36
Why do Manitoban waters drain into Hudson Bay?
Because the glaciers during the ice age were thicker/heavier over northern Manitoba so Manitoba is sloped
37
Has Manitoba always been full of lakes?
No, there have been many warming periods where Manitoba has experienced drought. Lake Winnipeg has even dried up and been overgrown with trees
38
What are Sub glacial lakes
Permanently covered by ice
39
How do higher acid concentrations affect heavy metals?
Make them more toxic
40
How are lagoon lakes formed?
When current from lake deposits so much sediment that it cuts a small part of a lake off from the rest
41
Where was the first hydro dam in Manitoba?
Point du Bois
42
Cryogenic lakes are located ________
On permafrost
43
How are thermokarst lakes formed?
Melting form houses, dumps, railways
44
What are bog lakes?
Caused by growth of sphagnum moss, which creates acidity and blocks drainage
45
Hydro dams cause a buildup of mercury in lakes - why is this? What's the big deal?
Methyl-mercury is often leeched from hydro flooded soils.
Methyl-mercury is so toxic that a tiny amount can kill someone
46
What are reservoirs?
Man-made lakes
47
How are saline lakes created?
Often present because rivers terminate. The water has nowhere else to flow so the only removal of water is through evaporation - this leaves salt and other deposits in water
48
What is Bathymetry?
The study of underwater depth of ocean floors (like scuba maps)
49
What are the important topographic factors of a lake
Islands, elevation, surface area
50
Which Manitoban lake used to be known for it's floating islands and giant leeches?
Sewell
51
How is the littoral shelf created? Does this exist in precambrian shield lakes? Why or why not?
The littoral shelf is created by waves - which erode the sides of a lake underneath a beach, creating a "littoral shelf" uo on which macrophytes can grow and still be in the photic zone.
No littoral shelf in precambrian shield lakes because the bedrock is too tough to erode
52
Most of the heat of a lake is absorbed in the top ______
1m
53
In winter, the lowest level of a lake has a temperature from ____ to _____ degrees Celcius
4 to 6 degrees
54
How do lakes lose heat?
Radiation to environment, evaporation, conduction
55
______ is the amount of heat put in a lake over a year
Heat budget
56
What occurs to the water bodies flowing into Indian Bay when the City of Winnipeg aqueduct pumps water out?
Indian bay loses water so quickly that new water from Shoal Lake and Lake of the Woods must be taken. The top-most layer of water is taken, disrupting any biological communities and causing a lowering in temperature
57
Above the thermocline is the _______ and below the thermocline is the cooler _______
Epilimnion, hypolimnion
58
In spring and fall, the epilimnion and hypolimnion are ________ temperatures because ______ occurs
The same, overturning
59
______ can drive thermocline deeper, or create more than one thermocline
Storms
60
What is the problem with early fall freezup in a lake?
Animals depend on turnover for oxygen so if the lake freezes over too quickly many fish can die
61
Describe the thermal regimes of lakes and how they vary season to season
During spring water is mixed and there are no distinct layers. In summer the epilimnion is at it's deepest, and a lot of algae grows in this layer. There is no mixing, and as a result the hypolimnion can become anoxic because of the sheer amount of dying algae (which are eaten by bacteria that use O2).
In the fall, as temperatures cool, the epilimnion gets smaller and smaller until there is complete mixing.
In the winter a layer of ice covers the lake, followed by a very cold thin layer between 0 and 4 degrees. The rest of the lake is about four degrees, and there is no mixing
62
Describe a surface seiche
Occurs when very strong winds blow against lake and cause it to slosh back and forth violently - can cause flooding
63
A _____ consists of layers that do not mix. Describe in detail why this is
Meromictic. Often because of amount of dissolved substances and weight of each in different layers. Can be caused by organisms dying and making the bottom water more dense. Can be caused by photosynthetic organisms producing products that fall to the bottom. Can also be caused by mine tailings, less dense incoming water, or water from springs (crenogenic) containing many dissolved solids may join lake.
64
_______ lakes overturn constantly
Holomictic
65
Describe amictic lakes
Do not circulate, permanent ice cover. May be a uniform temperature throughout or may be warmer on bottom due to geothermal heating
66
Differentiate between cold and warm monomictic lakes
Cold monomictic:
Temperature ever over 4 deegres. Covered in ice in winter, never stratifies, spends all summer mixing and melting
Warm monomictic:
Circulate in winter, stratify in summer, never under 4 degrees.
67
______ lakes experience regular spring and fall overturns
Dimictic
68
_____ lakes have irregular circulation. Where are they located
Oligomictic, which are tropical
69
Describe polymictic lakes
Continuous circulation. Mostly tropical or shallow.
70
The heat budget of a lake increases the _____ the lake gets
Larger
71
List the types of arrhythmic water movement
Vertical convection currents
Wind induced currents
Density currents
Turbidity currents
72
Describe vertical convection currents
Top water cools down from evaporation, wind, etc. and warm water upwells to take it's place
73
Describe wind-induced currents
The greater the surface area of the lake, the more significantly wind induced currents are. Water can be piled up on one end of the lake as a seiche. When this happens the undercurrent moves water in the direction of the wind.
74
Describe Langmuir cells
Wind streaks. Helixes rotate parallel to the wind direction underwater and reverse direction from their adjacent helix. Surface convergent zones occur along line where two helixes are downwelling, and surface divergent zones occur along lines where two helixes are upwelling. These convergent and divergent zones create lines of materials floating on the surface.
Distance of each Langmuir cell will be half the distance between two convergent lines
75
Describe density currents
River flowing into a lake will find the strata which it's density requires, and create a current through the lake in that stratum
76
What occurs when water carries silt load which adds to density
Turbidity currents
77
Distinguish between laminal flow and turbulent flow
laminar - uniform, parallel, low velocity, small stream diameter (larger streams need current to hardly move to achieve laminar flow), very uncommon
Turbulent - discombobulated, non-parallel, cause eddy effects
78
Water encounters resistance when it hits water of a different consistency, producing vortices called _______
Eddies
79
What is helpful about eddies?
Keep sediments moving (prevent too much deposition), maintain plankton in photic zone, transfer heat, move sediments from current to water and vicé versa
80
Surface waves are ______ water movements
Rhythmic
81
How are surface waves produced?
When wind hits a water surface, it displaces water which builds up a crest. Water is displaced in an orbital inside the wave crest
82
What conditions must be present to get white crests on waves?
Ratio of height to wavelength exceeds 1:10. The white crests are the waves toppling over
83
If the wavelength (λ) is greater than 2πcm the wave is called ________.
If the wavelength (λ) is less than 2πcm the wave is called ________.
Surf occurs when wave height is ______% of λ
Gravity wave, ripple, 77%
84
What is the fetch of a wave?
Downward distance from shore to cresting wave (AKA distance wind has travelled uninterrupted)
85
What is undertow?
Breaking waves on shore causing water to flow underneath incoming water. Can drag people down underwater
86
How are groins hazardous on Lake Winnipeg
Groins are structures used to trap sediment (sand) moved by the wind so a cottage-goer can have a beach.
Areas between groins erode very rapidly and cottages can collapse as a result
87
What is an internal seiche?
Hypolimnion sloshes back and forth underneath epilimnion, displacing upper water and changing thermocline. The anti node occurs where there is the most vertical displacement and the node is the lower as with least vertical displacement
88
In larger lakes, seiches have a period of several hours. For example, a seiche on Lake Eyrie takes ______ hours
2
89
During a seiche, what does the thermocline do?
Swings up and down along nodes in a periodic manner. This can be caused by extra weight on thermocline, heat differentiation.
90
What are the three types of nodal systems in internal currents? What causes these?
Uniondal (one node), binodal (two nodes), plurinodal (multiple nodes, associated with flooding and drying).
Can be caused by pressure change via rain or atmospheric conditions
91
Currents can also be displaced by _____ and _____
Coriolis affect and lunar tides
92
Describe the concentration of nitrogen, oxygen, and co2 in air
Nitrogen - 78.1%
Oxygen - 20.9%
CO2 - 0.03%
93
Any gas in the atmosphere can build up in a water body, but what gases are found almost exclusively in water bodies?
Methane, nitrates, nitrites, H2S (hydrogen sulfide)
94
If temperature goes up, total dissolved gases goes ______.
If pressure goes up, total dissolved gases goes ______.
If total dissolved solids go up, total dissolved gases goes _____.
Down, up, down
95
There is approximately _______% less dissolved gas for every 100m in altitude
1.4%
96
What affect do dissolved solids have on pressure?
Increase
97
Oxygen is limited in lakes with _____ total dissolved solids
High
98
Describe how the presence of N2 affects a lake
Dissolved N2 is mostly inert and rarely affects a healthy ecosystem.
However, when nitrogen fixing bacteria overtake a lake (eutrophication), usable nitrogen goes up so much that the lake can be affected
99
List factors that affect oxygen solubility
Temperature, total dissolved substances, pressure, waves, moisture content of gas (dryer dissolves more rapidly), eddy currents carry deoxygenated water to surface
100
In order to have a healthy lake, tons of ______ must be present
Oxygen!
101
_______ supplies most of the oxygen in lakes
Photosynthesis
102
Oxygen in a lake is mostly limited to ______, and concentrations are lowest at ______ (time of day)
Photic zone, dawn
103
Why are oxygen concentrations lowest at dawn?
Because oxygen was used up all night without be replenished
104
The warmer the water, the _____ the rate of respiration
Higher
105
Describe orthograde vertical oxygen distribution
Almost unchanged top to bottom, seen in oligotrophic lakes in summer or lakes that are currently circulating
106
Describe clinograde vertical oxygen distribution
O2 goes up in gradient from bottom to top (low amount on bottom, level at thermocline, high as it reaches the top)
Found in eutrophic and meromictic lakes. Lots of productivity but lots of oxygen depletion
107
Describe heterograde vertical oxygen distribution. What specific kinds of organisms can cause this?
Consistent across water column with bump in the middle - either positive or negative bump.
Positive can happen if oxygen producing algae (or macrophytes) are found in a band all growing at the level where the bump is found.
Negative can happen if zooplankton are found in a band or if a stream brings in a layer of sewage.
Phytoplankton are found most at ~3-10m deep, so that an cause positive heterograde.
Stenothermal algae grow well at low temperatures and low light conditions so they may be found even deeper.
108
What happens to O2 concentrations in winter
Become stratified and water on bottom can be anoxic. Fish can die because so much decomposition occurs (using up O2)
109
Define the two types of BOD
BioCHEMICAL oxygen demand - oxygen needed to oxidize all organic and inorganic substances in system
BioLOGICAL oxygen demand - oxygen organisms in system are consuming
110
______ lakes have huge differences in day-night O2 concentrations
Eutrophic
111
If pH of a system is <6, ___ and ____ are dominant forms of CO2
CO2, H2CO3
112
If pH of system is 6-10, dominant form of CO2 is ____
HCO3-
113
If pH of system is >10, dominant CO2 form is ______
CO3-2
114
When CO2 dissolves in water ___% becomes hydrated
1%
115
How does CO2 prevent rapid pH changes
Acts as buffer - forms carbonic acid
116
How does CO2 enter a water system?
Runoff, rain, groundwater, decomposing
117
What is total alkalinity
Ability of water body to neutralize acid, measured in mg/L CaCO3
118
How is acidity buffered in limestone lakes?
Conversion of H2CO3 to CaCO3
119
What does hardness of water mean? What about softness?
Hardness releases to magnesium and calcium ions present
| Softness means it has almost no calcium
120
What is "marl"?
Sparkly white film at bottom of lake consisting of mostly calcium carbonate that has a high pH
121
In clinograde lakes, predominant CO2 forms are _____ and _____.
CO2 and bicarbonate
122
In winter time CO2 _____
Increases
123
The major process that depletes CO2 is ______
Photosynthesis
124
When aquatic plants have little access to CO2 what do they use? What is a byproduct of this?
Bicarbonate ions (Ca(HCO3)2). CaCO3 is released as a precipitate (causes crustiness of plant)
125
When bicarbonate is broken down, what occurs? What does this mean for the system?
Hydroxyl ion is released and pH increases. This means that there must be day-night fluctuations in pH thanks to plants.
126
The higher the day-night pH change, the _____ the primary production
Higher
127
Can CO2 be a limiting factor?
Near the end of summer, CO2 used in photosynthesis exceeds CO2 respirate because CaCO3 drops to bottom as precipitate. This can mean lower CO2 levels and potential limiting.
128
One small plant can precipitate ___% of it's body mass in CaCO3 in 10 hours of sunlight
2%
129
Where does methane come from in lakes? How does it function in a healthy system.
Comes from anaerobic decomposition of organic matter by bacteria. In a healthy system methane-oxidizing bacteria convert methane to CO2 95% of the time.
130
Describe methane levels in winter
When lake is stratified, methane may build up. And in the winter the lake can become super saturated and the methane may bubble to the surface.
This most often happens in shallow, warm waters like bogs
131
What are sulphate levels like in precambrian shield waters
Below detectable levels
132
Why is excess sulfur a problem? Where does it come from?
Sulphates turn to toxic H2S is the water and fall to the bottom. During turnover the H2S moves to the top of the lake and can kill many fish. This is a big problem in precambrian shield lakes because they are not equipped to deal with it.
Excess sulfur can come from hog barns, pulp/paper mills
133
Calcium is the most abundant ion every where in mb but ______
Precambrian shield
134
Having higher dissolved solids ______ conductivity
Increases
135
Soft water lakes have _____ Ca levels. Hard water lakes have _____.
Super low, very high (including precipitate)
136
Bottom sediments in lakes can take in ____ and ____ to bring system back to normal
Sulfur, phosphorous
137
Calciphobes often live in _____
Bogs
138
Talk about magnesium. Discuss it's abundance, uses, and forms it is found in
Second most abundant cation in non precambrian shield lakes. It is needed for photosynthesis (in chlorophyll) and is very common in limestone lakes. Common forms are peso mite and dolomite. Vertically there is not much difference in Mg concentrations
139
Why is more soap needed when using hard water
Calcium and magnesium bind to soap
140
______ are water bodies with high NaCl
Salterns
141
Describe sodium abundance and usage in lakes. What forms is it found in?
Extremely abundant and soluble, evenly distributed through water column. Usually found as NaCl.
Can be found as halite, Na2B4O7 (gives us borax), Na2SO4, NaHCO3 and Na2CO3.
NaHCO3 and Na2CO3 are found in soda lakes with high pH. These lakes are great for Cyanobacteria
142
Lakes with K2CO3 instead of Na2CO3 are called _____
Potash lakes
143
Describe potassium. How abundant is it? What does it do?
Found in abundance. Primary producers (macrophytes and cyanobactefia) like to hoard it. Only extremely productive lakes have major vertical potassium differences
144
______ is the most abundant heavy metal in the earths crust
Iron
145
Distinguish between ferric and ferrous iron. Are they soluble?
Ferric: Fe+++, insoluble
Ferrous: Fe++, soluble when there is no oxygen and no CO2 present.
146
Ferric vs ferrous iron proportion is influenced by _____
pH
147
Huge organic compounds called ______ often combine with iron.
Humates
148
What happens to iron in eutrophic lakes?
Cannot be soluble so it slowly bonds to hypolimnion
149
Manganese gives off a _____ colour, is ____ soluble than iron and is ____ stable around oxygen.
Brown, little bit more, more
150
How many genera of bacteria and Cyanobacteria are nitrogen fixers
28 genera of bacteria, 21 genera of Cyanobacteria
151
More nitrogen = _____ biomass in system, but _____ species diversity
More, less
152
How does N2 gas affect an ecosystem?
It doesn't. Only nitrogen fixing prokaryotes with nitrogenase can use it, and they convert it to usable nitrogen
153
Describe how nitrogen fixers work
Some are chemosynthetic and can operate under no or little light.
Nitrogenase does not work when oxygen is around photosynthetic bacteria need to separate photosynthetic elements of the cell from nitrogenase
154
Describe how ammonia is created in lakes and how it is removed
N2 gas is converted by nitrogen fixers into ammonia, which is converted by nitrifying bacteria into less toxic NO2. Oxygen is required to convert NH3 into NO2, so if a water body is eutrophic this step may not occur. In a healthy system there should be very little ammonia.
Ammonia can also build up from excretion by aquatic mammals and decomposition of organics
155
There are higher concentrations of NH3 in what layer a lake:
Hypolimnion
156
Describe a way (other than nitrification) that NO2 can be introduced into a system
Can be reduced from NO3 by denitrifying bacteria
157
What is the allowable level of nitrate in drinking water
<5μg/L
158
Why is the nitrogen cycle so tricky?
Depending on the compound, it can take years to degrade nitrogen
159
Phosphorous is typically the ______ factor in a system (about ___% of the time)
Limiting factor, 90%
160
What are the forms in which phosphorous is found?
Inorganic in rocks, soluble inorganic (readily available), soluble organic phosphorous, particulate organic phosphorous (in organisms)
161
How does the phosphorous cycle differ from other nutrient cycles? How is extra phosphorous introduced into ecosystems?
Phosphorous goes through a long period where it is locked up in rocks at bottom of lake.
Extra phosphorous comes from decomposition of organisms, runoff, deforestation, industrial operations
162
List the phosphorous and nitrate content of eutrophic lakes
PHOSPHATE (μg/L)
>25
NITRATE (μg/L)
>600
163
Describe the water column phosphorous and nitrogen content in oligotrophic and eutrophic lakes
Oligotrophic - similar phosphorous and nitrogen along water colum
Eutrophic - variable
164
Macrophytes like to store large quantities of phosphorous. How are they able to accomplish this?
Sediments in lakes contain higher quantities of phosphorous than the water does. Macrophytes can take up and hoarse phosphorous from sediments, then release it all back when they die. Leaves/roots take in as much phosphorous as they can and this can lead to shortage of phosphorous for other organisms
165
What is the Redfield ratio?
Per 100 grams macrophytes/algae, 1g P: 7g N: 40gC
166
Distinguish between eukaryotic and blue green algae in terms of health of lake
Eukaryotic algae are mostly good (ex. Can be consumed, don't release toxins), but blue green algae are bad and they snuf out all other organisms. They bloom, die quickly, deplete oxygen during decomposition then add more nitrogen to the system, perpetuating the problem.
167
What causes collapse of photic zone?
In hypertrophic lakes oxygen depletion, algal toxins, and destabilization of aquatic community (drowning out light) all contribute. All are caused by blue green algae
168
What are signs of eutrophication
Increased productivity, algal blooms, decreased light penetration, decreased biodiversity, increased sediment, decreased macrophytes production
169
List the sources of N and P in Manitoban waters
Domestic sewage, agriculture, manufacturing industries, logging and land clearing, solid waste, recreation, mining, deliberate addition to tap water
170
Explain in detail how inadequate sewage treatment affects Manitoban waters
We still don't filter our wastes for nitrogen!
Harmful wastes include: human body wastes, dish soaps, phosphate/ammonia cleaners (though there are regulations, many dishwasher detergents are exempted), household products, garbureters, effluent, tap water treatment, illegal chemical disposal
171
Describe sewage treatment
Sewage treatment occurs in steps. Bacteria eat some portions.
Small communities empty wastes straight from lagoon into creeks or streams.
Rural homes usually don't notice sewage breaks - sewage goes all over field
172
Explain what the city of Winnipeg does to our tap water
City of Winnipeg adds orthophosphate to tap water because otherwise lead in pipes downtown would kill us
173
Why is chlorination of water so problematic?
It causes production of chloroform, which is not a great thing
174
What are the top three contributors of nitrogen in Manitoban
1. Agriculture 2. Sewage 3. Cottages
175
Describe how cottages affect nitrogen and phosphorous levels
Newer cottages have a holding tank for their wastes, but older ones may have a septic field.
Often cottage owners will shoot a hole in their septic tank so the sewage can seep out. They then do not need to have sewage pumped as often
176
Describe how chemical fertilizers affect Manitoban surface waters
Liquid ammonia is extremely volatile and tends to flow off fields (especially since there are no trees to stop it). Crop spraying happens all at once so the soil does not have time to absorb all of it. Agricultural and municipal drainage brings in extra nitrogen.
Certain plants inhibit seed growth and must be burned (stubble burning).
Agricultural chemical storage facilities easily leak.
Agriculture Manitobwnrecommends putting fertilizer on fields in the Dall
177
Describe how manure and farm animals affect Manitoban surface waters
Large farming operations, especially those involving factory hog barns contribute huge amounts of nitrogen to Manitoban waters (MANURE!!). Manure can be stored in temporary, above ground tanks with a tendency to rupture. Some farmers use lagoons to store animal wastes.
Illegal manure dumping occurs when manure is dumped on nearby fields.
Winter spreading is illegal only in larger operations - occurs when farmers spread manure all winter so it runs off with spring melt.
178
Describe how slaughtering plants affect Manitoba surface waters
Dump things like animal insides, wastes, toxic chemicals
179
Which types of landfill waste affect Manitoban surface waters the most
Carcasses, food waste, pet waste, chemical containers, garden/yard clippings, kitchen waste, hospital waste, degradation products of synthetic solids
180
How do livestock mortalities affect Manitoban surface waters
Often livestock die of disease and are illegal dumped in water sources
181
How do cemeteries affect Manitoban surface waters
On banks of streams/rivers. Nutrients from dead bodies get into water supply
182
How does logging affect Manitoban surface water?
Logging and pulping causes lots of nutrient runoff into lakes and rivers
183
How do pulp mills affect Manitoban surface waters?
Release highly concentrated Nitrogen and phosphorous as well as chlorinated by products from bleaching of paper
184
How do forest fires affect Manitoban surface waters
Ash contains concentrated nutrients that get spread all over a great distance
185
How does Mining affect Manitoban surface waters
Cyanide is used in processing gold, and it turns to nitrogen in the water.
Acid is used to dissolve the rock off of minerals and often drains into lakes and rivers.
Main tailings have toxic levels of many substances - arsenic being one of them
186
How does smelting affect Manitoban surface waters? Where are Manitoban smelters located?
Acids from smokestacks kill vegetation and cause soil to wash away. Located in Flin Flon and Thompson, the lakes are full of lead and cadmium. Affects are permanent and cause increased cancer risk for community
187
What is mined in Manitoba?
Copper, nickel, zinc, gold, tantalum, and caesium
188
How do hydro dams affect Manitoban surface water communities?
Can't have a littoral community because water levels fluctuate so much. There is also major copper enrichment as a result. 1/3 of fish die when they hit a dam, and another 1/3 die of their injuries later.
In lake Winnipeg the hydro dam affects shoreline erosion
189
Dams increase residence time of nutrients by _______
3x
190
Why is flooding so harmful to lake Winnipeg
When it floods, every farm, landfill, and lagoon is swept up and it all drains into lake winnipeg
191
Sulphur is found primarily as_______ in water, and is in higher concentrations in ______ waters
Sulphate, saline
192
Which areas have the most sulphur?
Volcanic areas, red river valley (soil is clay so it absorbs sulphur to form gypsum and pyrites).
193
Why is sulphate necessary in aquatic ecosystems? Explain how sulphur is changed by bacteria
SO4 is needed by algae and macrophytes.
H2S enters system and is converted to useful SO4 by bacteria.
Colourless sulphur bacteria then convert SO4 back to H2S, but this process releases acids
194
How is sulphur different from other organics
Degrades more slowly
195
_____% of the earths crust is silicon dioxide
60%
196
Distinguish between silica and silicon
```
Si2 = silica
Si = silicon
```
197
Which organisms require silicon? Can it be a limiting factor?
Diatoms and other crysophytes require silicon. So do some invertebrates (ex. Porifera).
Can be a limiting factor in summer when diatoms die and silicon is held in sediments
198
Why is chloride so important in aquatic ecosystems? How is excess chloride added?
Required by all plants and algae as the "water-splitter" in photosynthesis. It is used in small quantities and can be reused, so adding chloride to a system is unnecessary and harmful.
Excess is added via road salting, sewage, livestock. Usually found in low quantities where there are no roads.
199
What heavy metals are needed as micronutrients for most organisms? Why are heavy metal levels so important to maintain? How is this related to pH?
Manganese, iron, copper (toxic to fish), molybdenum zinc. Some require boron, cobalt, iodine, selenium, sodium, vanadium as well.
Heavy metals are necessary for life, but only in minuscule amounts. They become toxic at higher concentrations. All heavy metals are present in natural ages but not all are essential (ex. Lead).
Heavy metal levels in a lake are a measure of health
If pH is high then more heavy metals can dissolve and the water gets more toxic (this is present on east side of lake winnipeg).
200
What factors affect toxicity of heavy metals in a lake? Why are these a big deal for precambrian shield lakes?
pH, phosphorous content, dissolved organics, and hardness (calcium and magnesium bind to metals, making them less toxic) affect toxicity. Precambrian shield lakes are soft water lakes and therefore cannot protect well against heavy metals pollution
201
What substance is used to kill algal blooms? Why is this problematic?
Copper sulphide (CuSO4). It is toxic and illegal, but not one monitors it. It never degrades. Cottagers use it to kill leeches and weeds in the water, and it is extremely toxic to snails. Copper is also toxic to fish
202
List some extremely toxic heavy metals.
Arsenic, uranium, aluminum (kills mussels), mercury, cadmium
203
Aside from decreasing pH, why is high acid rain a problem?
Increases aluminium concentrations so much that it can kill all fauna in a lake
204
Trace elements influence algal types. What type of algae is found in lakes with high cadmium? What about high manganese?
Cadmium - Cyanobacteria
| Manganese - fewer Cyanobacteria, lots of diatoms
205
What are some of the forms of dissolved organic matter? Wher do they come from?
Alcohols, carbs, fatty acids, amino acids, pigments.
Come from allochthonous (external) or autothonous (internal) sources.
Allochthonous - inflow, runoff, leaf litter, soil leeching
Autothonous - Excretion, death of organisms
206
____%-____% of dissolved organics are carbohydrates.
70-90%
207
What role do dissolved organics play in an ecosystem
Can be absorbed by algae.
| Bind to stuff, either reducing toxicity or lowering nutrient levels
208
How can dissolved organics be measured?
Vaporize water, measure what's left
209
There is always _____ dissolved organic matter than particulate matter
More
210
What do humolimnic acids cause in a water body?
| Distinguish between these and humic acids
Humolimnic acids are organics that cause a yellow colour in lakes. They don't readily compose and can inhibit photosynthesis. They are found in large amounts in Bog lakes.
Humic acids contain a benzene ring in their structure whereas humolimnics do not
211
What are dystrophic waters? Use bog waters as an example
Cannot fall into other trophic categories - make no sense.
Bog waters are deficient in Calcium, nitrogen, and are species poor and acidic. Large amounts of humolimnic acids are present
212
What negative effects do algal blooms have on ecosystems?
Oxygen depletion, shading (block out sun), destabilization add death of aquatic communities, secrete toxins (neurotoxins, hepatotoxins, lipopolysaccharide toxins)
213
What does skunk weed do in an ecosystem?
Skunk weed is an alga called "Chara" and it excludes competitors. It is perennial and lives in alkaline lakes
214
Elodea and myriophyllum produce ______ repellent
Daphnia
215
Myriophyllum produces a snail repellent called ______
Myriophyllin
