Earth 206 Exam 2

progressing and retreating glaciers

"u" shaped valley

reversing the chicago river

- flowed into lake michigan - carried sewage into the lake which was the source of chicago's drinking water - reversed when canal was dug 1900

particulate phosphorus

30% bioavailable

braided pattern

= high slope + high stream power + coarse bed materials

littoral zone

a shallow zone in a freshwater habitat where light reaches the bottom and nurtures plants

60%

about ______ of these nuclear power systems use recirculating cooling; the remainder use once-through cooling

195 m

average depth of lake huron

9.8%

hydroelectric % of U.S. electricity generation

kW/s

power

ordovician (485-443 mya)

separate land masses, mountains (taconic highland), carbonate bottom eperic sea and deep ocean

submergent plants

stonewort, coontail, bladderwort

1 kW x hr = 3.6x10^6 joules

the amount of energy that will keep an electrical heater running for one hour

river formation

"v" shaped valley

chippewa phase

- 10.0 - 5.5 kya - extreme drop in lake levels (retreating glacier uncovered a very low outlet) - much of the lake plain dried up - 2 deepest areas still had water - rebounding slowly raised the level of the north bay outlet and with it the levels of lakes huron and michigan

factors that affect pH

- algal blooms - bacterial activity - water turbulence - chemicals flowing into the water - sewage overflows - pollution

silurian (443-419 mya)

- as the sea regressed, precipitation of evaporites occurred in the appalachian basin, ohio basin, and michigan basin - in the michigan basin alone, ~1500 m of sediments were deposited, nearly half of which are halite and anhydrite (gypsum) - coral reefs tend to grow until they restrict water circulation, beginning a cycle of evaporation

proposal to reduce P levels

- avoid runoff (avoid frozen and snow-covered ground applications, incorporate nutrients into soil - conduct more frequent and more accurate soil tests - make use of cover drop more widespread - hydraulic buffers (install filter areas, restore wetlands, controlled drainage)

building of great lakes

- central park of N America experienced repeated transgressions and regressions of shallow tropical seas during the paleozoic - large areas of tropical coral reefs deposited layers of material that become sedimentary rocks - the most significant structure in the region is the michigan basin, a broad, circular basin surrounded by large barrier reefs

methods to alleviate negative impact

- creation of ecological reserves - limiting dam construction to allow substantial free flowing water - building sluice gates and passes that help prevent fishes getting trapped

present lake michigan

- current level was reached 1500 ya - lake currents move sand to S and deposit it at the southern end of the lake - weather patterns cause lake level to fluctuate seasonally - may rise >1 ft from late winter low level to a summer high and then back down again

effects of sediment deposition

- decreases the fertility downstream as a long term effect - deprivation of sand to beaches in coastal areas - salt water intrusion into the inland from the ocean, as the previous balance between this salt water and upstream fresh water in altered - changes in ecology of the estuary area and lead to decrease in agricultural productivity

nature of hydropower

- generation of electricity using the flow of water as the energy source - sun/gravity as source - considered cleaner, less polluting than fossil fuels

photoautotrophic

- gets energy from sun - created its own carbohydrates from CO2 - most phytoplankton

impact of zebra mussels on algal blooms

- high filtering capacity created positive feedback in cycle of algal blooms - can filter up to 1 L water per day (lowers the N:P ratio, selective grazing on phytoplankton)

eutrophication

- high nitrogen and phosphorus levels - when algae decay, they use up oxygen in the water making it hypoxic - by the 1970s the lake was declared dead

pollution in lake erie

- industrialization began around the lake in the 1820s - deforestation, urbanization, destruction of natural wetlands - industries dumped chemical and wastewater into the lake - untreated sewage and runoff from agriculture

future of great lakes

- lake level will most likely drop again - level of lakes michigan and huron is determined by the level of lake erie into which they flow - depends on the erosion of niagara falls, because as the falls erode away, levels in lake erie will drop and so will lakes michigan and huron

potential causes of increased DRP

- larger farms (changes in type and size of equipment, increase in soil compaction, spreading work load over the year) - "stale seedbeds" - uncertain use of soil testing - changes in soil quality - phosphorus stratification in upper soil

zebra mussels effect on N:P ratio

- low demand for phosphorus due to body composition allows them to excrete more P as feces/pseudofeces and then dissolved into water column as DRP readily available to phytoplankton - leads to changes in N:P --> favors growth of species with a low N:P ratio

retreat of the ice margin

- main lines of evidence for process come from the end moraines left behind - the saginaw lobe was thinner than the lake michigan and erie lobes and therefore melted faster and was the first to begin its retreat - glacial meltwater and precipitation drained southward to the gulf of mexico - sand and gravel, which these meltwater streams could not carry, was laid down as outwash in broad, flat outwash plains

laurentide ice sheet

- moved south from canada - important for great lakes formation - ice cap spread southward to ohio and missouri river valleys (north: 3-6 miles thick, south (ann arbor): 1 mile thick) - temperatures about 15-20C colder than today (avg ~freezing)

phosphates

- naturally occurs in rocks and minerals - plants uptake weathered-out elements and compounds - animals ingest plants - water-soluble

nitrates

- naturally-occurring form of nitrogen found in soil - forms by microbial decomposition of fertilizers, plants, manures or other organic residues - uptake by plants

expected outcome of zebra mussels

- reduced frequency and intensity of algal blooms - alleviation of anoxic zones - improved water quality

water hardness

- reflects dissolved metals such as Ca2+, Mg2+, Fe2+, often from carbonate minerals - high alkalinity = hard water

controversy/problems with hydroelectric energy

- require the development of vast amounts of infrastructures (dams, reservoirs, power plants and power lines) - environmental problems (alteration of the environment, changing the nature of rivers, creating lakes that fill former valleys and canyons, etc.) - dams are frequently located upstream from major population centers

interference with sediment transport

- rivers carry a lot of sediments - creation of a dam results in the deposition of sediments on the bottom of the reservoir - land erosion on the edges of the reservoir due to deforestation also leads to deposition of sediments

turbulent mixing

- the lake surface is exposed to the wind, which mixes the surface water, but the turbulent energy from the wind dissipates with depth, having less impact further down

river water components

- water - suspended material (clay, silt, sand) Si, Al, Fe, Ca, K, Mg, Na, and P - dissolved major species: HCO3-, Ca2+, (SO4)2-, H4SiO4, Cl-, Na+, Mg2+, K+ - dissolved nutrient elements - suspended and dissolved organic matter (major: N,P, minor: Cu, Zn) - bedload transport - trace metals (can be nutrients and/or toxic)

how pH affects aquatic life?

1. decreasing pH (e.g. acid rain) 2. release of Al, metals 3. toxic conditions 4. chronic stress 5. smaller, weaker fish

dissolve oxygen (DO) sequence

1. increase in organic waste 2. increase in algae/plant vegetation 3. decrease in DO available to organisms 4. leads to changes in ecosystem as organisms needing lots of DO are replaced by organisms needing little

dissolved reactive phosphorus (DRP)

100% bioavailable; the portion which is dissolved and can immediately support plant and algae growth

the ice ages

2.5 mya

fission

235U (and 239Pu) + neutron --> fission fragments + 2-3 neutrons + energy!

neutron capture and beta-decay

238U + neutron --> 239U --> 239Np --> 239Pu

4%

U.S. gets about ________ of total energy from this source

scarp

a long steep slope or cliff at the edge of a plateau or ridge

pressurized water reactor

a nuclear reactor in which the fuel is uranium oxide clad in zircaloy and the coolant and moderator is water maintained at high pressure so that it does not boil at the operating temperature of the reactor

boiling water reactor

a nuclear reactor in which water is allowed to boil in the core. the resulting steam is used to drive a turbine generating electric power.

limnetic zone

a zone of open water in lakes and ponds

steam-cooling step; water reuse for generation

accounts for virtually all of the water used in most power plants

alkalinity

acid-neutralizing capacity of solutes in a water sample - buffering capacity - resistance to pH changes - common natural buffer: (CO3)2- - protects aquatic life - commonly linked to water hardness - natural systems: 50-150 mg/L as CaCO3

turbines

advanced, very efficient waterwheels. they are often enclosed to further capture water's energy

4

all nuclear power plants in michigan are located by the great lakes. how many are there?

watershed

an area of land that drains all the streams and rainfall to a common outlet

1 kW

an electric heater (1 kW) or small car engine (60-100 kW)

1970s

annual algal blooms, but decreasing in intensity and number

lake nipissing great lakes

as the ice retreated further into canada and glacial rebound occurred to the north, lakes superior, michigan, and huron united into one huge body of water called the

279 ft; 925 ft

average and deepest depths of lake michigan

500 ft; 1332 ft

average and deepest depths of lake superior

550-300 million years ago

bedrock chemistry of great lakes was determined about

benthic zone

bottom of an aquatic ecosystem; consists of sand and sediment and supports its own community of organisms

cambrian (541-485 mya)

canadian shield (land) and islands surrounded by eperic sea and deep ocean, carbonate bottom

emergent plants

cat tail, bulrush, wild rice

trihalomethanes

chloride levels went from 11.4 to 92 mg/ml because of ___________________ levels that can form through reactions between organic matter in water and chlorine disinfectant added at treatment plants

regions that don't have seasons

could there be places or situations where you don't have this twice-a-year turnover?

disadvantages of water power

dams have multiple problems; reservoirs have impact on ecosystem; reservoirs can cause earthquakes

interlobate/lateral moraine

debris left between the space of two glaciers which closely approached each other

- dams and reservoirs - bank stabilization of rivers - soil conservation practices

decreases of suspended load

hypolimnion

deepest layer of uniformly cold water that does not mix with the upper layers and has low circulation. colder water within this layer is a max temperature of 4C

removing zebra mussel

dredging, biological control, hormonal disruption

HCO3-, (SO4)2-, Cl-, Ca2+, Mg2+, Na+, K+

each lake has an ion balance of the 3 major anions and 4 major cations

environmental considerations of dams

fish/wildlife = fish ladders, deposition of sediment, flooding (dislocation of people)

october 2015

flint emergency was declared in

D. 1 million years

for how long are we supposed to make predictions on the stability of nuclear waste repositories against attack from water/corrosion, earthquakes, land slides, and potential terrorist attacks A. 1 year B. 100 years C. 10,000 years D. 1 million years E. 10 million years

ohio river

formed at southern boundary of ice sheet

ice-marginal (proglacial) lakes

formed where land in front of the ice margin sloped toward the glacier, allowing meltwater to pond there

great lakes and bays that eventually occupies the enlarged depressions after the ice had disappeared

glacial lobes are named according to the

terrawatt (10^12 W)

global energy use; 15 TW = 15,000 nuclear reactors

lake michigan love

grand traverse and green bay appendages

head

height from which water falls; equivalent to voltage; ft

small meanders

high gradient, coarse substrates

high level waste (HLW)

highly radioactive materials produced as a byproduct of the reactions that occur inside nuclear reactors

D. they came along with ships

how did we get zebra mussels into the lakes? A. they escaped from a zoo B. they were intentionally introduced C. they travelled as a parasites with other fish D. they came along with ships

1 kg/2.2 lbs

how much does a liter of water weigh?

p = (efficiency(friction) x discharge x head)/11.8

how much electricity can be generated by a hydroelectric power plant?

1. other 2. china 3. brazil 4. canada 5. u.s. 6. russia

hydropower by country

movement of ice sheet

ice moved as a series of lobes: - each lobe sought out the lowest spots on the landscape - these were mainly ancient river valleys - slowly lobes made their way southward out of the old widened river valleys - during the climax of the last, or wisconsinan stage of glaciation, all the lobes were united south of the great lakes region - southermost limit reached ~20 kya - about 200 miles south of chicago

michigan basin

if the bedrock of michigan could be sectioned, it would appear as a bowl or basin, with the youngest rocks at the center and the oldest at the edges

denitrification, iron reduction, ammonium production

if you have a similar alkalinity curve, but no sulfate reduction, what could product this?

C. was mainly covered by an ocean and surrounded by a coral reef

in the silurian period A. michigan was covered by an ice sheet B. looked similar to today C. was mainly covered by an ocean and surrounded by a coral reef

thermocline; hypolimnion

in unusually transparent lakes, photosynthesis may occur well below the _____________, into the perennially cold:

- deforestation and cultivation - overgrazing - construction

increases of suspended load

11.8

index that converts units of feet and seconds into kW

superior lobe

keweenaw lobe as an offshoot

after: treated flint river water

lack of a corrosion inhibitor, high chloride levels, and other factors cause the passivation layer to dissolve and fall off, leading to increased corrosion in flint's pipes. as the pipes corrode, chlorine disinfectant breaks down; oxidants such as dissolved O2 corrode pipes and leach soluble metal (Fe2+)

173 m

lake erie

lake erie

lake exposed to the greatest effects from urbanization and agriculture

176 m

lake huron

176 m

lake michigan

ottawa - st. lawrence rivers detroit - st. clair rivers illinois-mississippi rivers

lake nipissing great lakes

74 m

lake ontario

183 m

lake superior

lake superior

lake with the largest surface area (of any freshwater lake in the world)

thermal stratification

lakes in temperate regions have vertical layers that very in temperature and density

1990s

large algal blooms of microcystis in 1995 and 1998

nonpoint sources of phosphorus

lawn care fertilizers, storm water, orthophosphate in treated water, dishwasher detergent, agriculture

15 ppb

lead levels deemed safe by EPA

exponentially

light intensity decreases _______________ with depth in a lake

1%

light level of about ____ or less of surface values usually define the depth of the littoral zone

megawatt (10^6 W)

lightning strike or power 1,000 average homes

pitting corrosion

localized accelerated dissolution of metal that occurs as a result of a breakdown of the otherwise protective passive film on metal surface. pH within the pits tends to be lowered significantly

big meanders

low gradient, fine substrates

20

low-head hydropower systems are generally less than ______ feet high

perennial or permanent rivers

maintain water throughout the year

temperature and oxygen

major factors regulating aquatic organisms

oxbow lake

meander that has been cut off from the river

dissolved oxygen (DO)

measurement of oxygen dissolved in water and available for fish and other aquatic life; can range from 0-18 ppm

metalimnion

middle layer characterized by a streep gradient in temperature and demarcated by the regions above and below. barrier that separates mixing and heat exchange between the epilimnion and hypolimnion

5-6

most natural systems require _________ ppm to support a diverse population

A. terminal and lateral moraines of the ice ages

most of the relief that we see in ann arbor is the result of A. terminal and lateral moraines of the ice ages B. anthropogenic activities such as excavations C. tectonic activity D. very old volcanic activity

laminar flow

much less common and occurs only in water that is moving very slowly. it is a smooth flow with all the water molecules moving parallel to each other at the same speed and with no mixing between them

turbulent flow

much more common and arises as the velocity of the water increases. it is characterized by irregular, random motion, which occurs when the water molecules move in different directions and at different velocities from the average of the flow

stream channel

narrow pathway carved into sediment or rock by the movement of surface water

corrosion

natural process, which converts a refined metal to a more stable form, such as its oxide, hydroxide, or sulfide. it is the gradual destruction of materials (usually metals) by chemical reaction with their environment stable Pb(0) to a mobile state (dissolved Pb2+)

1980s

no massive algal blooms, zebra mussels arrive

- light water - heavy water - graphite - other moderators

nuclear chain reactions only work well for further fission if slowed down by

B. 0.61*0.01*0.03 = 0.00018 or 0.018%

of all the water in the earth's near-surface region (top few miles within the earth's surface including the icecaps, groundwater, and the oceans), the fraction of water that is in lakes is A. 4/10 of a percent B. 0.61*0.01*0.03 = 0.00018 or 0.018% C. 4/10*0.01*0.03 = 0.0000012 or 0.00012%

almost 1,800 pounds of coal

one uranium pellet =

uranium enrichment

only 235U can be more easily fissioned than the more common 238U

lake michigan

only great lake entirely in US

plankton and detritus

organisms that go where the water takes them

fish, amphibians, turtles, larger zooplankton and insects

organisms that go where they choose

benthos, plants, bacteria, and fungi

organisms that live on the lake bottom

77%

percentage of water used in michigan for hydrothermal power plants

52%

percentage of water used in u.s. for hydrothermal power plants

before: treated detroit water

phosphate corrosion inhibitor helps maintain a mineral passivation layer on the inside of flint's pipe's, protecting them from corrosion. with little corrosion, chlorine disinfectant levels remain stable

coal, natural gas, oil, nuclear fission, and some renewable energy technologies

plants fueled by ______________________________ boil water to produce steam, which then turns a turbine to generate electricity

- no corrosion control used - lower pH - higher chloride content (as a result of ferric chloride use, chloride to prevent bacterial infection)

reasons for higher corrosion rates in flint?

advantages of water power

renewable; no greenhouse gases, air or water pollution; dams have multiple uses; cheap (4 cents per kWh)

modern great lakes

result of: - erosion and deposition by the glaciers - blockage of drainage by glacial ice - subsidence of the land beneath the glacier's immense weight, following by rebounding of land during and after glaciation - postglacial lowering of the lake outlets by erosion

waterwheel

revolving wheel fitted with blades, buckets, or vanes; convert the kinetic energy of flowing water to mechanical energy

75%

rivers drain nearly ______ of the earth's land surface

episodic rivers

rivers that hardly ever flow because they are in low rainfall (arid) areas and the water table is always below the river bed

periodic rivers

rivers that only flow during the rainy season when the rainy season water table is higher

1960s

seasonal algal blooms caused by cultural eutrophication

turbulent mixing

seasonal pattern of __________________ is also a critical determinant of ecosystem function and community structure

legionnaire's disease

severe, often fatal bacterial disease characterized by pneumonia, dry cough and sometimes gastrointestinal symptoms; probably caused by low levels of chlorine as disinfectant

lake erie (averaging 62 ft)

shallowest great lake

respiration (water column and sediment), decomposition, diffusion

sinks for oxygen in a lake

wind, photosynthesis

sources of oxygen in lakes

huron lobe

subordinate saginaw lobe

lake turnover

summer and winter: stable stratification, not much mixing fall and spring: turnover

C. 6 times the discharge of the huron river

the amount of water needed to cool (and produce the steam) of a classical once-through power plant is equivalent to the discharge of A. 1/6 the discharge of the huron river B. about the same as the discharge of the huron river C. 6 times the discharge of the huron river

34 kWh

the average american uses roughly _______ of electricity daily, 90% from thermoelectric power plants

climate (affects hydrology) and basin geology

the chemical composition of a lake is fundamentally a function of its:

thalweg

the deep part of a channel where most flow occurs

rise

the difference in density per degree of warming increases as temperatures:

B. legionnaire's disease

the flint water crisis brought about which bacterial infection A. cholera B. legionnaire's disease C. influenza D. rubella

B. ice lobes that followed preexisting fluvial valleys

the great lakes were predominantly created by A. tectonic activity B. ice lobes that followed preexisting fluvial valleys C. volcanic craters D. water erosion

density

the layering of lake waters due to ___________ differences is a major factor structuring the ecosystem and creating distinct habitats

C. water gets heated up and causes thermal pollution (causing potentially algae blooms and disabling the water holding enough oxygen)

the major environmental impact on the water that goes through a nuclear power plant is A. that it is radioactively contaminated when it goes back to the river B. that there is a lot of radioactivity in the steam that's coming out of the cooling tower C. water gets heated up and causes thermal pollution (causing potentially algae blooms and disabling the water holding enough oxygen)

B. has the youngest geologic layers in the center of michigan

the michigan basin A. has the oldest geologic layers in the center of michigan B. has the youngest geologic layers in the center of michigan C. was created by a meteoritic impact at thr end of the cretacious D. was created by the last ice age

nuclear fission

the most water intensive method of the principle thermoelectric generation options in terms of the amount of water withdrawn from sources

fluvial transport

the movement of eroded sediments (solid and dissolved materials) by flowing water in streams

sinuosity

the quality of curving in and out; determined by gradient and substrate

flow rate

the quantity of water flowing in a given time; equivalent to electric current; ft^3/s

turbine generator

the shaft of the turbine spins a magnet inside coils of copper wire. it is a fact of nature that moving a magnet near a conductor causes an electric current

epilimnion

the surface layer of water that is constantly mixed by wind and waters and is warmed by the sun, from late-spring to late-fall

estuary

the tidal mouth of a large river, where the tide meets the stream; more erosion; st. lawrence

4 trillion, 90%

the u.s. produced roughly _________________ kWh of electricity annually, ________ from thermoelectric power plants

C. flint river water as a temporary solution until a new pipeline to lake

the water source that needed to be treated before going to flint households was A. the same source (lake huron) as was used by the detroit water supply, they just had to treat it themselved B. a new well in lake huron C. flint river water as a temporary solution until a new pipeline to lake huron was ready to go D. flint river water as a terminal solution

D. they are located right next to a huge water body such that cooling may be less required

there are some nuclear power plants that don't seem to have cooling towers. what is the most likely reason? A. they just forgot to build them B. it's just old style C. those reactors don't get that hot because it's a different type of reactor D. they are located right next to a huge water body such that cooling may be less required

2000s

toxic microcystis common in western basin, trend toward increasing frequency of microcystis blooms

1 watt

typical lightbulb (25-100 W)

gigawatt (10^9 W)

typical nuclear reactor or power a city the size of san francisco uses

37% petroleum 32% natural gas 11% renewable energy 11% coal 8% nuclear electric power

u.s. primary energy consumption

euphotic zone

upper layer of a body of water through which sunlight can penetrate and support photosynthesis; occurs within the epilimnion

run-of-the-river system

uses the river's natural flow and requires little or no impoundment. it may involve a diversion of a portion of the stream through a canal or penstock, or it may involve placement of a turbine right in the stream channel; often low-head

5 kW

usually ratios lesser than _______ per hectare implies that the plant needs more land area than competing renewable resources

atmosphere

volume of lake superior is equal to the volume of water in the:

lake erie

warms rapidly in the spring and summer, and is frequently the only great lake to freeze over in winter

transuranic waste (TRU)

waste that contains manmade elements heavier than uranium on the periodic table

point sources of phosphorus

wastewater treatment plants, combined sewer overflows and bypasses, industrial discharges, home sewage treatment systems

warmer

water holds less gas

0.0001% of the total amount of water in the world

water in rivers

floating plants

water lily, duckweed, pondweed

damming rivers and harnessing water to drive turbines to generate electrical energy

water power is produced by

voltage (J/C) x current (C/s)

watt =

delta

wetlands that form as rivers empty their water and sediment into another body of water; more deposition; mississippi, nile

- which fuel cycle? - nuclear waste disposal - diversion of nuclear material and proliferation of nuclear weapons - environmental impact of normal operation of nuclear fuel cycle - catastrophic accidents

what are the issues with nuclear energy?

oxygen, nitrate, Fe3+, sulfate, CO2

what is being used as energy source/breathing material/electron acceptor as you go down in an anoxic sediment?

B. adding nitrate to the drinking water

what is not an appropriate measure to remediate lead release into flint drinking water supply A. adding phosphate to the drinking water B. adding nitrate to the drinking water C. wherever possible, replace lead pipes by other materials D. reduce the amount of chlorine in the water

#2 by area, #4 by volume

what is the rank of lake superior in terms of size (worldwide)?

lake huron

what lake has the longest shoreline?

lake superior

what lake is the deepest?

yucca mountain, nevada

where do we put spent nuclear fuel?

the sun

where does the energy for hydroelectric power come from?

C. plutonium

which element that is not naturally occurring but generated in a reactor will contribute to the water contaminated in the vicinity of geologic repository? A. radon B. uranium C. plutonium D. arsenic

B. hydro, nuclear, and coal

which energy forms contribute relatively more to the production of electricity than their percentage of primary energy sources A. hydro, nuclear, and oil B. hydro, nuclear, and coal C. oil and gas D. oil and renewables

D. erie

which is the shallowest of the 5 lakes A. superior B. huron C. michigan D. erie E. ontario

B. st. lawrence

which of the following rivers has an estuary at the end? A. mississippi B. st. lawrence C. nile D. amazon

C. contaminants typically travel faster than the actual water

which of the following statements on the response (discharge) of a river system to a rainfall precipitation event is incorrect A. direct channel precipitation is smaller than surface runoff because the surface area of the river is smaller than the surface area of the drainage basin B. channel precipitation is followed by surface runoff and then by interflow and groundwater flow C. contaminants typically travel faster than the actual water D. if a contaminant makes it all the way to the groundwater, it can take years until this contaminant is detected in the river water

C. spent nuclear fuel

which of these nuclear waste types produces the highest amount of radiation? A. uranium mine and mill tailings B. depleted uranium C. spent nuclear fuel D. contaminated water

C. contaminated water

which of these nuclear waste types produces the highest volume of waste material? A. uranium mine and mill tailing B. spent nuclear fuel C. contaminated water

C. hydroelectric

which one of the following is not considered a thermoelectric power plant? A. nuclear B. coal C. hydroelectric

inside moves faster than outside; slower movement = deposition

why do rivers become braided/meandering?

tilted thermocline in lake michigan

wisconsin in slightly colder than michigan; water pushes east

39% coal 20% natural gas 16% nuclear 15% hydro 7% oil 2% renewables

world electricity generation

33% oil 27% coal 21% gas 6% nuclear 2% hydro 11% solar, wind, other

world primary energy consumption

caspain sea and ural river

zebra mussels are native to; brought to lake st. clair via ballast water in transoceanic commercial cargo ship in late 1980s

selective grazing

zebra mussels directly affect population size of phytoplankton and blue-green algae through herbivory; very selective of size of particle ingested, favors growth of certain larger phytoplanktonic species, removed direct competitors

positive feedback of zebra mussels

zebra mussels filter high volume of water > excrete high levels of P & selective grazing of smaller phytoplankton > favored growth of bloom-causing algae and blue-green algae