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235 Cards in this Set

  • Front
  • Back
What is limnology?
The study of/science of inland waters.

Running water and standing water.
Dissect the word limnology into its greek components.
From the word limne - meaning a pool, marsh, or lake

and logos - meaning the study of
Lentic habitats
Standing waters
(ponds, lakes, wetlands)
Lotic habitats
running waters (rivers, streams)
Is limnology REALLY freshwater biology?
NO.
Purists would say that it is not just freshwater biology because it also includes the study of saline pools and lakes found in arid regions (like the Great Salt Lakes)
Limnology - importance as an ecological science
6 reasons
-distinct borders of lakes have led to their study as units
-limnology has attracted ecologists that are interested in the behavior of whole systems
-contributed a disproportionate number of guiding conecept in ecology
-work on energy flow, material flow and ecosystem modeling.
-Important manipulation studies have been conducted on large enclosures and whole lakes, and on experimental stream channels
-the role of inland aquatic water bodies as a component of an integrated land-water system
How much of the surface area of the earth is covered by water?
>75%
How much of the earth's water is in the oceans?
>99%
How much of the earth's water is freshwater?
< 3%

much is tied up in glaciers
How much water of landmasses is stored in groundwater aquafers?
85-95%
How much of freshwater demand is consumed by agricultural irrigation?
85%
Of the water used for agricultural irrigation, how much is lost to the atmosphere due to wasteful and inefficient application to soils rather than crops?
A whopping 50%.
What is the second most water consuming activity?
Cooling processes in the generation of electricity, with losses again by evaporation.
How much water does manufacturing consume in the U.S.?
20%.
In industrial countries, how much water does the average human consume (all uses)
1500 liters/day
What is the absolute minimum amount of water a human consumes per day to meet physiological needs?
2 liters
In developing countries, how much average water does a person consume every day (all uses)
400-500 liters/day.
What are sources of water degradation?
6 things
Direct discharge of toxic contaminants into surface and ground waters.
Nutrient loadings.
Saline intrusion into ground waters.
Anthropogenic loadings (acid rain, toxic rain).
organic matter (sewage)
sediment loadings.
Responses to water degradation:
Many things
Try and obtain more clean water
move to a cleaner source
locate deeper aquifiers
Apply technology in piecemeal fashion, usually to deal with an acute crissis rather than to prevent problems
Water quality problems

(essay question?)
Develop in a consistent way.
Start with pristine supply.
Slight change in quality with increase of human settlement and agricultural development.
Major impacts follow due to increased industrialization.
Deterioration impacts water uses, primary treatment costs don't work anymore.
Technical and political policies are implemented, with delays/red tape before controls become effective.
Pollution controls are often implemented successfully only in industrialized colonies.
The result is a satisfactory situation, but water is not pristine.
Recovery costs are much greater if pollution had been controlled before dilution into aquatic environment.
What costs of water should include.
(Water quality problems)
The total costs of acquisition.
Transport and distribution.
Treatment after use.
Release of water after use should only be permitted in:
Purified form, with its biological and chemical quality better than or equal to its original source.
Strengths of freshwater systems:
Resilience (especially above ground supplies)
Quick turnover in many systems.
Biota is generally resilient.
Evolutionarily young and generally occupies broad niches.
Systems are highly valued.
Weaknesses of freshwater systems
Freshwater basins lie at bottom of catchments and thus, reflect what is happening in the whole catchment.
As there is a limited supply of freshwater, it is vulnerable to pollution.
There is a natural tendency for basins to collect sediments and fill in.
Morphometry
Methods of measuring and analyzing the physical dimensions of a lake.
What kind of insight can morphometry give?
Insight into lake productivity or potential productivity of phytoplankton, fish, etc. of a lake.
Bathymetric map
An outline of a lake along with its submerged contours drawn to scale.
Five important pieces of information that can be obtained from an aerial photograph of a lake.
1. Maximum length (l)
2. Breadth (b)
3. Surface Area (A)
4. Shoreline length (L)
5. Shoreline development index (Dl)
Maximum length
(l)
The distance between the two most distant points on the shoreline.
Fetch
The distance over which wind-driven waves travel without encountering obstructions.

The longer the fetch, the more powerful the waves.
Breadth
(b) - maximum width of the lake measured perpendicular (90 degrees) to the maximum length line.
Mean breadth (b-bar)
Calculated by dividing the surface area by the maximum length.
Surface area
The area at Z0, or zero depth.
Best measured by digitizer program or planimetry. Can also be measured by grid enumeration analysis (omega lake) or by calibrated weight method (hypo lake).
What three things does the surface area of a lake affect?
Evaporation. (volume also affects this)
Surface deposition (can be important for nitrogen)
Input of solar energy (primary production is often measured per unit area)
Shoreline length.
How can it change?
How is it measured?
(L)
The length around the shoreline.

It can change due to precipitation, evaporation, or drawdown in reservoirs.

It can be measured on a map with string, dividers, a cartometer, Olson's method, rotometer.
Shoreline development index - Dl -
The ratio of the length of the shoreline to the length of the circumference of a circle with the same area as the lake.
What value of shoreline development is a perfect circle?

What are some nearly circular lakes?
1.0

Montezuma's Well.
DL = 1.04

Crater Lake
DL - 1.27

Cayuga Lake, one of the finger lakes
DL - 3.3 (not very circular)
Isobath
Contour on a bathymetric map.
Maximum Depth
Zm
subject to change due to drought or flood and as lakes age they tend to fill in with sediment.
Relative depth
Zr
The ratio of the maximum depth to the mean diameter of the lake surface expressed as a percentage.
Cryptodepression
Zc
If a portion of a lake is below sea level it is referred to.

Ex. Cayuga Lake (Zc = 17, because it's Zm = 133 m. It's surface is 116 meters above sea level.
Volume:
How is it determined.
( V )
Obtained by determining the volume between each of a pair of contour lines, where h is the depth between contour 1 and 2, and then summing all of these pieces to obtain the total volume.

Can be obtained by a hypsographic curve.
Hypsographic curve
A plot of depth versus area at each of the contours.

The line crosses the depth axis at the maximum depth.
Mean Depth
Z bar.
Volume over Area.
Morphoedaphic index
Ratio of dissolved solids to mean depth.
Why is geology important in lake formation?
Processes are almost entirely geologic in nature.
Ontogeny
The history of an organism since it's birth.
The fate of all lakes.
Once lakes are formed, their basins are fated to fill in with sediments.
Succession of Lakes
Does not always follow a smooth process.

Maybe...early -> mature -> senescence -> end as terrestrial.

Sometimes lakes are rejuvenated.
Final stages of succession
marshes, swamps, swampy meadows, forests.
Benthic Zone
The bottom regions of a lake.
Benthos
The animal community of bottom dwelling organisms.
Littoral Zone
The near shore region of lakes where the sediments lie in the photic zone and where the shallow water flora is frequently dominated physically by macrophytes.
Littoral Zone:
1. subject to...
2. type of bottom sediment
3. light and plants
1. temperature fluctuations, erosion of shore materials through wave action, grinding of ice
2. coarse bottom sediment, especially near unprotected shores
3. Well lit. Rooted with plants with associated animal fauna.
Sublittoral zone
1. type of sediment
2. light and plants
3. oxygen content
4. Relative amount of animal species
1. fine grained
2. Dimly lit and lacking a benthic macroflora.
3. Usually well oxygenated.
Shell zone
A zone with shells of gastropoda and Pelycopoda shells.
Within sublittoral zone.
Limnetic or pelagic zone
The open water part of a lake is little influenced by the shoreline or bottom.

Habitat of plankton - phytoplankton and zooplankton
Trophogenic zone
Upper well illuminated layer of limnetic zone. Photosynthesis occurs during daylight, resulting in carbon fixation.
Nekton
The free swimming animals in ponds or lakes (like fish)
Compensation depth
depth at which 1% of surface illumination penetrates.

Marks boundary between trophogeneic zone and the tropholytic zone.
Tropholytic zone
where respiration and decomposition predominate.
Profundal zone.
1. temperature, depth, light, oxygen
2. sediments
Occurs in lakes deep enough to undergo summer stratification (associated with hypolimnion)

1. deep, cold, minimum light, low oxygen
2. fine, mostly produced within the lake
epilimnion
Upper horizontal region of the lake, well mixed by the wind.
metalimnion
middle zone characterized by a rapid change in temperature with a depth called a thermocline.
Hypolimnion
The unmixed bottom.
Oligotrophic lake.
Nutrient-Poor lake.
Tends to be oxygenated throughout the year.
Eutrophic lake
Nutrient-rich.
May be anoxic at depths (in hypolimnion) and near sediments, especially in the summer.
E/H ratio
E is the epilimnion volume and H is the hypolimnion volume.
Low E/H ratio.
Large stores of deep water oxygen. (2ry oligotrophy)
High E/H ratio
Little oxygen is in the hypolimnion so oxygen is rapidly depleted, plus also more sediment-nutrient interactions.
Bog lakes
Northern lakes that are protected from the wind and that are poorly drained.

Often fringed with floating vegetation that grows inwards and encroaches on the open water.
Dystrophy
Shown by bog lakes that are deficient in calcium such as those in the Canadian shield.

Stained waters are acidic, brown in color, and low in electrolytes.

They tend to have reduced transparency caused by colloidal particles and dissolved humic materials.

Tend to have low primary productivities.

Recent work has shown that bacterioplankton are often important component of dystrophic lakes.
An example of dystrophy
Lake Matheson. Rich in dissolved organic carbon.

Organic acids lower the surface tension of the lake's water, contributing to the mirrow like surface and beautiful reflections.
Trophic status
related to primary productivity. The quantity of inorganic carbon fixed by plants and algae.
Primary productivity of:
Oligotrophic lakes.
Mesotrophic lakes.
Eutrophic (natural) lakes
Polluted (enriched)
7-25 g C/m2/yr
25-75 g C/m2/yr
75-250 g C/m2/yr
350-700 g C/m2/yr
Primary productivity of:
Montezuma Well, Arizona
California brine pools
Kenyan Soda Lakes
Ethiopian soda lakes

(all of these lakes are desrt pools and soda (NaCO3) )
798 g C/m2/yr
1420 g C/m2/yr
3900 g C/m2/yr
5000 g C/m2/yr
Natural eutrophication
Some lakes are naturally eutrophic.
Cultural eutrophication
Human activities have resulted in eutrophication in many lake systems by increasing nutrient loadings.
The two main plant nutrients.
Nitrogen and phosphorus.
Sources of nitrogen:
(3 things)
Atmospheric deposition (especially nitrate)

agricultural fertilizer

sewage
Sources of phosphorus:
(4 things)
Some atmospheric, but less than nitrogen.
Agricultural fertilizer
Industrial (especially detergents)
sewage
What is the limiting nutrient in terrestrial ecosystems?

What is the limiting nutrient in aquatic ecosystems?
Nitrogen.

Phosphorus.
(in northen hemisphere)
(in africa, nitrogen is limiting)
The role of phosphorus in metabolism.
Phosphorus has a role in nearly all phases of metabolism.

-Energy transformation of phosphorylation during photosynthesis
-synthesis of nucleotides, phospholipids, sugar phosphates and other phosphorylated intermediate compounds
-phosphorus is bonded as an ester in low molecular weight enzymes and vitamins that are essential to metabolism.
The main source of phosphate in aquatic ecosystems.
Orthophosphate (PO4 3-)
Ratio of main nutrients in plants.
1P:7N:40C per 100 grams dry weight or 500 grams wet weight.
If one of three nutrients in aquatic system is limiting, and X nutrient is available in excess, how many times its weight can X generate?
X=
1. Phosphorus
2. Nitrogen
3. Carbon
1. 500x
2. 71x (500/7)
3. 12x (500/40)
Large scale experiments conducted by David Schindler in the Experimental Lakes Area of Canada (NW Ontario).

What did this show?
Showed that phosphorus (phosphate) has a profound effect on the eutrophication (nutrient enrichment) compared to nitrogen and carbon.

For eight consecutive years, the side receiving phosphorus developed eutrophic algal blooms, while the side receiving only carbon and nitrogen did not.
What is the growth of various types of phytoplankton and algae is dependent on?

What is the critical value of the group of these organisms?
The phosphate concentration and its recycling rate.

20 micro gl-1 PO4-P
What are the main species of planktonic algae in
1. Oligotrophic lakes
2. Mesotrophic lakes
3. Eutrophic lakes
1. Cyclotella comta
2. Fragilaria crotonensis
3. Oscillatoria rubescens
What is the most frequently used secchi disk in limnology?
The 8 inch diameter metal disk painted in alternate black and white quadrants.
Method of using secchi disk.
1. Lowered into lake by unwinding the calibrated rope until observer loses sight of it.
2. The disk is then raised until it reappears.
3. The depth of the water where the disk vanishes and reappears is the Secchi disk reading.
4. The depth level reading on the calibrated rope at the surface level of the lake is recorded.
Which bacteria can fix atmospheric nitrogen?

What is their limiting nutrient?
Cyanobacteria (formerly blue-green algae).
They do this in their heterocysts.

Often phosphate limited.
Can form dense algal blooms in systems with high concentrations of dissolved phosphate.
Three cyanobacterial genera that cause problems for lakes.
Anabaena, Microcystis, Aphanizomenon.

Affectionately known as Annie, Mickey, and Fannie.

Another mischief maker is Oscillatoria rubescens.
Dimictic Lake.
Mixes twice a year, in the spring and fall.
Strongly stratified in the summer, weakly inversely stratified in the winter with an ice cover on top and the warmest densest water at the bottom.
Monomictic lake
Mixes once a year, over the winter period.
Strongly stratified in the summer.
Most lakes and ponds in southeastern alabama are warm monomictic water bodies.
Oxygen concentration dynamics in oligotrophic lakes.
There is little primary productivity in these nutrient poor waters, and oxygen concentrations in the epilimnion decreases with increasing temperature in summer.

Oxygen concentration in hypolimnion is estimated to be higher because oxygen is more soluble in cold water.

Called an orthograde oxygen profile.

Oligotrophic lake - orthograde oxygen profile.
Why does ferric iron precipitate from the solution trapping iron, manganese, and phosphorus in the sediments in oligotrophic lakes?
Because the hypolimnion remains well oxygenated in the summer and the redox potential remains high.

So the phosphorus is not recycled and remains trapped on the sediments, keeping the lake nutrient poor.
Oxidation concentration dynamics in eutrophic lakes.
Oxygen levels in the epilimnion are increased by phytoplankton photosynthesis.
As plankton die, they drop out of the epilimnion into the hypolimnion.
It is there that oxidative processes break down the organic matter, reducing the oxygen concentration.
Anaerobic conditions follow.
Creates a clinograde oxygen profile.
Is the redox potential in the hypolimnion of a eutrophic lake high or low?

What does this do to the phosphorus?
The redox potential is low in the anoxic zone, resulting in increased solubility of manganase, ferrous iron and phosphorus, allowing them to be released from the sediment into the hypolimnion, where they can be resuspended at the fall turnover.
Why does a eutrophic lake remain eutrophic in regard to phosphorus?

How is this a problem?
Phosphorus resuspension caused by a low redox potential in the hypolimnion keeps the nutrients suspended in the system, not trapped in the sediment.

It affects our ability to rehabilitate a lake that has become eutrophic.
Phosphate loading:
1. Prime Source
2. Another Major Source
3. And Another Major Source
1. nutrients in treated sewage.
2. Surface drainage
3. overuse of lawn fertilizers
Phosphate loading in Gull lake
24% of total phosphorus input was from lawn fertilizers.
75% of lawns were already saturated with phosphorous and additions were unnecessary.
50% came from detergents
Eutrophication problems of lake Erie.
Led to severe hypolimnetic oxygen depletion especially in late summer
Led to the die off of larvae of the mayfly Hexagenia.
Mats of green filamentous alga Cladophora washed up on beaches.
Eutrophication treatment
"The Band-Aid Solution."
Initial approach was to kill algae.
Cupric copper (Cu2+) usually as copper sulfate (CuSO2) kills algae without harming other fish.
Used between 1912 and 1958 to reduce blooms near Madison, WI.
Really just a "band-aid" approach.
Thousands of tons of copper, 46 years, futile attempt.
Eutrophication treatment.
Modern chemical precipitation.
Three methods used:
Lime (calcium oxide)
Iron (various forms)
Aluminum (usually as alum - potassium aluminum sulfate).
Eutrophication treatment.
Modern recycling method.
Sewage water is pumped to a storage reservoir and time is allowed for human pathogens to die out, then the black water is used to farm agricultural land.
How much did the population of Seattle grow from 1865 to 1965?
From 300 to 1,200,000
In 1922, what did people do to relieve pollution problems in Lake Washington?
They made a diversion to carry the pollution caused by 30 outfalls of raw sewage to Pudget Sound.

The lake soon recovered to a healthy state.

They also started to treat their sewage.
In 1962, how much pollution discharge was there in Lake Washington?
76 million liters per day.
Mean depth of a lake has been claimed to have a marked influence on productivity. Why?
Mean depth determines how much of a lake's volume is in Euphotic or photosynthetic zones.

Shallow lakes are more productive than deep ones.
Gorham (1958) found that among rock basins there is a distinct drop in the ratio of maximum depth to mean depth from 3.0 in the shallowest to about 2.4 in the deepest. What did he attribute this to?
Changing shape from a V section to a U section.
Give two of the main concerns about using the Secchi disk depth to measure algal biomass in lakes.
Light attenuation are based on particles, not chlorophyll content.

Size and chlorophyll content of cells are not infinitely variable nor independent.
Edmondson notes that on several occasions in Lake Washington deep values recorded for the Secchi Disk have been associated with relatively high chlorophyll values. What was the cause for this?
The population was dominated by large colonies of anabaena and aphanizomenon - the water looked crumbly but clear.
In lake washington, in the mid 50's, the lake was showing sign of eutrophication, in particular...

what were the difference in secchi disk depth due to this?
Algal blooms of Oscillatoria Rubescens.

Secchi disk depths went from 3-4 meters in 1950 to less than 2 meters in 1957.
On lake washington, what did Edmondson observe about phosphate concentration and summer algae and secchi disk depth?
As phosphate concentration decreased, so did the amount of summer algae, while the Secchi disk depth increased.
Another cause of eutrophication in rural lakes in both Europe and North America.

2 ways of eutrophication.
Weekend Cottages.

Have no sewage lines attached, water from dishwashers and washing machines soak into the ground.

Owners used fertilizers for lawns.
The U.S. and Canadian Government ask the IJC to do a report on eutrophication, under the terms of the Boundary Waters Treaty of 1909.

4 recommendations:

Which was the most controversial?
1. That phosphates in detergents be reduced to minimal levels
2. Remaining phosphates in sewage reduced by 80%
3. Programs be developed for reduction of input from agriculture
4. Any new changes in addition of phosphates to waters in the basin be regulated.

The phosphate reduction in detergent was the most controversal.
How much of the phosphate in sewage was from detergents in 1969?
>50%
What was the result of the campaign against phosphate in detergents?
1972 Great Lakes Water Quality Agreement
In Lake Erie, by how much did the amount of phosphate increase from 1948 to 1962?

How much did the amount of nitrogen increase?

What was the resulting nitrogen to phosphorous ratio?
Five fold increase.

30%.

Went from 35:1 to 9.2:1
In lake erie, what was the change in secchi disk depth?
>9 meters to 7-14 centimeters.
In lake erie, problems in the central basin caused the hypolimnion to become anoxic. What did this kill?
The Mayfly Nymph, Hexagenia limbata.
What effect did the physical limnology of Lake Erie play in oxygen levels?
lake erie is a warm shallow lake with a thin hypolimnion. The sediment portion of oxygen depletion is up to 50%
Was low levels of oxygen in Lake Erie a sign of Eutrophication?
It was seen that way at first.

The sediment phosphorus regeneration during low oxygen episodes led to autofertilization. Made it difficult to see improvement.

There was evidence of anoxic events in the central basin in the years prior to eutrophication.
Factor that played a role in the recovery of lake erie eutrophication.
Zebra mussels filtering algae out of the water column.
Autochthonous material
Formed or originating in the place where found.
Material that originated within the lake.
I.E. sediment that originated from phytoplankton from within the lake.
Allochthonous material
Found in a place other than where they and their constituents were formed.
Material that originated from outside the lake.
Four major factors that determine the nature of lake bottoms.
1. Age of the Lake - young lakes more likely to have rocky or sandy bottom, older lakes have softer bottom, more uniform.
2. Size of the Lake - increased surface area allows greater wave action, so more erosion of shoreline.
3. Latitude and Climate - effects growing season, i.e. the accumulation of organic materials. The more rain, the more materials are washed in.
4.Soils and other edaphic factors - underlying geological formations, i.e. how easily eroded.
Sources of bottom deposits:
1. Biotic
2. Abiotic
1. Dead organisms
fecal matter
Shells, bones, etc
2. Wind blown material
Surface runoff
chemical formations, i.e. marl, calcium carbonate
Gyttja
Common sediment in eutrophic lakes.
Mostly originates from plankton.
Copropel
Replaced the Gyttja.
Fecal material of bottom organisms feeding on bottom sediments including the feces of others.
Coprogenesis - the production of copropel
Is dark brown with a neutral pH
Sapropel
Results from anaerobic decomposition
Dark brown to black
Contains ferrous sulfide, high concentration of methane and hydrogen sulfide
Does not support macrobenthos, because it's anaerobic.
Dy
Found in dystrophic lakes
Like copropel, but is more acidic due to organic acids
Yellowish brown
fibrous from plant material
Paleolimnology
Study of sedimentation in lakes
Sediments laid down in bands - varves
One varve/year, sometimes two
Associated with blooms after turnovers
Used to determine age and history of lake.
Sediment cores

How to examine?
Collected from lakes permitting an analysis of changes to the lake over time.

I.e. changes in the diatom communities in the lake associated with changes in trophic status from oligotrophy to eutrophy.

Combustion of 1 gram of sediment at 550 degrees celcius.
Combustion of sediments from Oligotrophic lakes.
Largely oxidized by anaerobic bacteria, resulting in a small loss in weight on combustion.
Combustion of sediment from Eutrophic lakes
Have a much higher loss upon combustion
Pollen analysis
Can reveal changes in the surrounding watershed of a lake.

See layers of pollen from forest, then pollen of grass when area was deforested, then pollen of crops when area was used for agriculture.
The suns energy is the product of...
Emitted into space as...
How much energy reaches the earth?
A HUGE NUCLEAR FUSION REACTION
electromagnetic radiation
Less than a billionth
Amount of solar energy reaching earth's atmosphere.

Amount of solar energy reaching earth's surface.
1.98 langleys per minute.
(solar constant)

1 langley per minute.
1. % of sun's energy reflected back into space
2. % of suns's energy absorbed by atmosphere
(divide it into % that runs water cycle, % that drives winds)
3. % that is captured by photosynthesis
1. 30%
2. 25%, 24% and 1% respectively
3. .02%
Suns energy reaches earth as what type of radiation?

Radiated back as what type of radiation?

How much does greenhouse gases retain of this?
Shortwave radiation
(< 3 microns)

Long wave radiation
(< 3 microns)

88%
12% escapes into space
Why is the sky blue?
The atmosphere scatters shorter wavelengths, or blue wavelengths
If the sky is white or gray, why?

If the sky is yellow or red, why?
Water vapor scatters radiation.

Dust scatters long wavelengths, yellow and red
What happens to infrared radiation from the sun, and what is it's wavelength?
Absorbed as heat, some is reradiated. (4-100 microns)
What is the main energy source of aquatic ecosystems?
Solar radiation.
What does the adsorption of solar energy and its dissipation as heat affect?
(3 things)
Thermal structure
Water stratification
Hydrodynamics of lakes and reservoirs
Adsorption of solar energy and its dissipation has marked EFFECTS on
Chemical cycles, metabolic rates, and population dynamics.
Total radiation reaching Earth's surface consists of:
Two things.
Direct Sunlight
Diffuse Skylight
Wavelengths:
1.Ultraviolet
2.Visible Radiation
3. PAR (photosynthetically active radiation)
4.Infrared radiation
1. 300-380 nm
2. 380-750 nm
3. 400-700 nm
4. 750-3000 nm
Radiant flux
Quantity of electromagnetic energy flow over time. (quanta per second)
Irradiance
Intensity or flux density.
Radiant flux per unit area of a surface.
Expressed micro-mol quanta m2/s
What has a higher energy, a quantum of violet light or a quantum of red light?
A quantum of violet light.
Shorter wavelengths have greater frequencies and thus greater energies.
When radiation reaches the surface of a lake, a small amount is reflected, the rest penetrates water where it is absorbed.

Proportion reflected depends on:
(3 things)
1. Angle of declination of the sun
2. Wavelength
3. Surface wave conditions
When there is strong wave action, how much can reflection increase by? (%)

Ice?

Snow?
30-40 %.

10%

70%
Light penetrating a lake is:
(3 things)
Scattered
Absorbed as Heat
Transformed into other energy sources (like photosynthesis).
Light extinction
The degree of light retention by a layer of water
Light transmission
Light passing through water
Light absorption
Diminution of light energy with depth by transformation to heat
Light attenuation
diminution of radiant energy with depth by both scattering and absorption
Strictly speaking, extinction only applies to...
The decrease of monochromatic light with parallel beams in pure solutions.

Such conditions are not met in lake water: light is polychromatic, suspended particles absorb and scatter light.
Vertical Light attenuation
Reduction of light intensity with depth due to absorption and refraction of light.

There is an exponential decrease of light with depth.
How much of light is converted to heat in the first meter of water?
53%.
Absorption Coefficient vs. Extinction Coefficient
Log10 - extinction coefficient
ln - absorption coefficient

Absorption coefficient is 2.303 X extinction coefficient
Total extinction coefficient has three components.
kt = kw +kp +kc

Total extinction = extinction due to pure water + extinction due to suspended particles + extinction due to dissolved substances.
Which wavelength of light penetrates the furthest?

The least furthest?
Blue

Red
Phytoplankton shifts the absorption maxima to...

Dissolved humic substances shift the maxima to...
Longer green wavelength

shorter yellow wavelengths
What can the secchi disk measure/indicate?
3 things.
Light conditions in a waterbody.
Indication of the trophic status of a lake.
Indication of the depth to which aquatic macrophytes will grow in a lake.
Lake districts
How lakes typically occur due to localized nature of events that form lakes.
The shape of the basin and surrounding watershed affects
4 things.
Drainage, nutrient input, stratification, distribution of dissolved gases and organisms.
What is more productive, a steep lake or shallow lake?
Shallow lake. Has to do with the area of the lake water in contact with the sediment.
How many types of lake origins are there?
These are organized into how many different categories?
76, 11
Category - Tectonic basin
All basins formed by movements of the deeper parts of the Earth's crust.
Fault
A break in the continuity of a rock or of a vein, with dislocation along the plane of fracture
Graben
A double fault. Lakes form in the slippage between two faults.
What is the deepest continental body of water on earth?

How much of the world's freshwater does it contain?
Lake Baikal.

More than a third.
What is the oldest documented lake on Earth?
Lake Baikal.

Began to form at least by the late Oligocene to Early Miocene. 20 t0 25 million years old.
What caused the isolation of the Caspian Sea and the Sea of Aral?
Uplifting and upwarping.
Indirect Basin Formation

Example of a lake.
Another example of a lake.
When upwarping causes the blockage of an outlet.

Great Salt Lake
Lake Victoria
Caldera

example
The result of collapse of the roof of a partially emptied magma chamber.

Crater lake
Maar

Example
Result from explosions beneath the earth's surface producing low rims of fragments

Laguna Atexcac
Why does La Preciosa become a distinctive turquoise color?
This may be an annual occurrence due to precipitation of carbonate particles when the lake waters become warmer
How was lake nicaragua formed?
By lava damming a valley.
Landslide lakes

Example.
The impoundment of stream valleys by rockslides, mudflows or other mass movements.

Usually short lived because the blocked stream will destroy the landflow.

Mountain lake in virginia.
Glacial lakes
The most important agent in the formation of lake basins.
Glacial lakes:
Lakes held by or in ice:
3 kinds
Glacially dammed lakes in lateral valleys - water percolates into frozen lakes from underneath. Not permanent.

Lakes formed between glacier and valley wall or between glaciers.

Lakes dammed by either ice or moraines of retreating glaciers.
Glacial Lakes:
Lakes formed in glacial rock basins.
Ice -scour lakes (i.e. Great Slave Lake)

Cirque lakes - small and shallow, formed at the heads of glaciated valleys.

Lakes can be formed by glacial erosion in non montaine origins.

Kettle lakes - formed when ice blocks deposited in glacial outwash material.
Kettle
depression formed when a block of stranded, buried glacier ice gradually melted out - causing the overlying land surface to collapse downward.
Glacial lakes:
Cryogenic lakes
Formed in permafrost from a periglacial frost thaw basin or from an ice mound called a pingo, often shallow, common in the arctic
Solution lakes
Result from percolating water dissolving soluble material below the ground.

A depression known as a karst develops.

Most result from the solution of limestone
Dolines
deep, circular pits formed from the percolation of water into soluble underground material.

(A type of solution lake)
Solution lakes:
Mound-Spring lakes

Example
based on solution and subsequent precipitation.

Australian mound springs.
Piping
False karst lakes which are formed in depressions in sandstone due to piping, which produces tubular subsurface drainage channels in insoluble clastic rocks.
Solution lakes are common in....

an example of a solution lake...
florida

montezuma's well
Fluviatile lakes
Lakes formed by river activity
Fluviatile lakes:
Lateral lakes
Formed as sediments are deposited at the mouth of stream tributaries
Fluviatile lakes:
Oxbow lakes
As a river meanders across a flood plain, the outer bends are gradually eroded and the water channel deepens as the loops widen, the neck of the loop narrows and finally gives way, allowing water to flow in a more direct route, isolating the old water channel and forming an oxbow lake.
Aeolian Basin
Caused by wind action, primarily in dry, arid regions
Aeolian basin:
Deflation basin
aka blowouts
Blown material piles up as a curved mound along the lee shore of a depression.
Lunette
Deflation basins along the lakeshore of Lake MIchigan
Aeolian basins:
Between dune basins.
The Sandhills of Nebraska.
What is the highest desert in the world?
The Qaidam Depression
Shoreline lakes
Lakes associated with coastlines.

When long shore currents flow by coasts indented by bays, inertia carries the current along the mouth rather than into the bay.

Material is deposited as a spit that can eventually cut off the bay as a coastal lake or lagoon.
Lakes of organic origin
Basins impounded or excavated by organisms, either plants or animals

Hutchinson considered each of these types separately.
Lakes of organic origin:
Vegetation blocks off a portion of a preexisting lake
This is common in low lying, humid, tropical regions.
In addition, this is the origin of lakes in coral atolls.

Lake Okeechobee
Lakes of organic origin:
Lakes produced by higher animals - beavers and man
beaver dams may be very extensive.
Meteoric craters

Ex.
Lakes formed by meteor crashes.

Chubb Lake, Quebec
Relic Lakes
Lakes that are relics of Glacial Lake Agassiz

Hutchinson considered these a type of glacial
How much water do the Great Lakes hold,
In America?
In the World?
20% of the world's water.
80% of water in North America.
What lake has the greatest Area and Volume in the world?
The Caspian Sea.
What did the early jesuit missionaries call the great lakes?

What has it become since?
The sweet water seas.
(They were fresh)

The world's biggest sewer.
How many people drink from the GL?
24 million people.
What species was driven to extinction in the Great Lakes? How?

What other species were endangered? How?
Atlantic Salmon.
Logging caused sedimentation of their spawning habitat and saw mill dams blocked access to spawning grounds.

Whitefish, cisco, and the blue walleye.
Overfishing.
The Great Lakes Water Quality Agreement of 1972
Concentrated on stopping the phosphate pollution, which was more obvious than the chemical pollution arising from the expanding industrial presence.
Which toxic chemicals have caused the most problems in the great lakes?
The halogenated organic chemicals.
DBP
Disinfection by-products.
Made when chlorine interacts with pollution.

Example: Trihalomethanes
What is the only viable treatment of DBP's?
Activated carbon filters on the sinks
Pollution:
1. Point

2. Nonpoint
1. Where the sources can easily be identified on a map

2. All other sources.
Land run off
sediments carry phosphorus, chemicals and pesticides.
What are the worst polluted areas of a lake?
Along the shorelines.
History surrounding the love canal.
Hooker chemicals spilled 19 tons of chemical waste into love canal.

The dump was then sealed over with a clay cap, sold to the board of education.

They built a school on it, and then the cap was damaged by it. Rain caused chemicals to seep out.

New york called for a state of emergency. Area was declared federal disaster area.
Hyde Park History
Hooker used THIS site for a dump after the love canal incident. 72,000 tons of chemical waste.

Dump was sealed. But the dump was on fractured limestone, chemicals are still able to seep into the river.
S-area dump
Built on rubble and fill on and old river bottom. Material that is permeable, allowing seepage into the niagra river.
102nd street
another dump!
It's leadking.
St. Clair River
Problems on this river caused by canadian chemical industry.

Dow discharged mercury.

Mercury converted to methylmercury due to microorganisms.

toxic and accumulates in fish and organisms.
The St. Clair River "BLOB"
Dow chemical claimed it to be a perchloroethylene spill.

Great concern that it pollution welling up from deep injection storage wells in old salt mines.
The largest and cleanest of the great lakes
Lake Superior
Thunder Bay
Polluted with mercury, toxic organics and sewage
What is the second largest and cleanest of the great lakes?
Lake Huron
3rd cleanest lake of great lakes
4th cleanest lake
5th cleanest lake (dirty)
lake michigan
lake erie
lake ontario
AOC
Areas of concern
What the IJC deemed areas of concern around the great lakes.
RAP
remedial action plan.
1. define the extent of the problem
2. identify use impairments
3. describe the causes of the problems.
4. identify remedial actions to resolve the problems with an implementation schedule
5. idenitfy organizations responsible for implementing and regulating the remedial actions.
6. describe the process for evaluating the remedial program implementation and effectiveness.
7. describe monitoring program used to track the effectiveness
RAP
three general stages to them
Remedial action plan
1. problem analysis
2. selection of preferred remedial action plans
3. implementation and monitoring
One of the worst AOCs is
Hamilton Harbor, Lake Ontario, which may be so badly contaminated that there is no safe way of cleaning it up other than waiting for clean sediments to cove
How do RAP help the community?
Give community a sense of environmental stewardship and pride in their progress towards delisting.