15. killerlakes04

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Killer Lakes

1) Why are the lakes of Cameroon “killer”?

2) What limnological phenomenon has takenseveral human lives on the Great Lakes?

3) How did poor communication turn a shallowlake in Louisiana into a “Killer Lake”?



www.montageplus.co.uk/commonlink/ findout/cameroon.htm

Cameroon, Africa

www.geology.sdsu.edu/how_volcanoes_work/ Nyos.html

http://www.montageplus.co.uk/commonlink/findout/cameroon.htm

http://www.montageplus.co.uk/commonlink/img/maps/cameroon.gif

http://www.geology.sdsu.edu/how_volcanoes_work/Nyos.html


http://www.montageplus.co.uk/commonlink/findout/cameroon.htm

http://www.montageplus.co.uk/commonlink/img/maps/cameroon.gif



15 August 1984

www.geology.sdsu.edu/how_volcanoes_work/ Nyos.html

37 people died mysteriously

In the vicinity of Lake Monoun

Rumors of terrorism and chemicaland/or biological weapons quickly spread

Cause of death was determined to be asphyxiation





www.school2.ru/~V.Mazin/ Nyos/Nyos1.html

Lake Nyos

Tropical Maar Lake

Probably only a few

hundred years old

About 1100 m wide,1900 m long and208 m deep

www.mala.bc.ca/~earles/ nyos-feb01.htm

http://www.school2.ru/~V.Mazin/Nyos/Nyos1.html

http://www.mala.bc.ca/~earles/nyos-feb01.htm




http://www.school2.ru/~V.Mazin/Nyos/Nyos1.html

http://www.school2.ru/~V.Mazin/Nyos/nyos_big.jpg



21 August 1986

At about 9:30 pm, a series of rumblings were

heard

Hundreds of people suddenly lost consciousness

The few survivors woke 6 to 36 hours later



Areas up to 10 km away from the lake were impacted

1700 people and 3000 cattlewere killed by asphyxiation

No birds, insects or small mammals were seen for48 hours

http://news.bbc.co.uk/1/hi/world/africa/487514.stm

www.disasterrelief.org/Disasters/ 990901lakenyos/

http://www.disasterrelief.org/Disasters/990901lakenyos/

http://www.disasterrelief.org/Disasters/990901lakenyos/



24 August 1986

Swiss missionary helicopters in the area report

the disaster to the “outside world”

www.geology.sdsu.edu/.../Thumblinks/ nyos_page.html

The once clearlake is now red-brown

http://www.geology.sdsu.edu/how_volcanoes_work/Thumblinks/nyos_page.html

http://www.geology.sdsu.edu/how_volcanoes_work/Thumblinks/nyos_page.html



George Kling

In 1985, he went to Lake Nyos to collect sedimentcores

What happened???

In 1986 international team of scientists rushedto the site

http://www.eeb.lsa.umich.edu/eebfacultydetails.asp?ID=74



Hypothesis 1:

A volcanic eruption at the bottom of thelake released toxic gas.

Survivors had felt warmth

Survivors had smelled “rotten eggs”

Evidence:

Some victims had burns and sores



Problems with Hypothesis 1:

No sulfur wasdetected in the lakewater, around thelake or on the deadbodies

No evidence ofcraters at thebottom of the lake

No hot water presentat the bottom of thelake

Kling et al. 1987



Hypothesis 2:

Limnological processes resulted in the disaster

CO2 (which is lethal in high concentrations)built up in the deep water and was somehow

released.

How did the gas build up and why was itreleased?



Tropical Maar Lake

Kling et al. 2001



CO2

CO2

CO2

Soda springs beneaththe lake release CO2 in the monimolimnion

At 200 meters,

water can hold 5 times its own volumein CO2



Prior to the explosion, it is estimated that1 L of water contained 1-5 L of dissolved gas

98-99% of this was CO2

Estimates are that 1.2 km3 of CO2 was released

Lake level droppedby over a meter

http://www.school2.ru/~V.Mazin/Nyos/nyos_big.jpg



What triggered the gas release?

Internal seiche

Seismic shock

Landslide

Heavy rain and/or flood



What about the fact that….

Survivors felt warm and had smelled“rotten eggs”

Some victims had burns and sores



How to keep this from happening again?

Solution— De-gas the lake

Problem— Who will pay for it?

How to de-gas in a controlled way?



The Office of Foreign DisasterAssistance, USAID

The Cameroonian Inter-MinisterialCommittee for the Nyos-Monoun Degassing Program

Degassing began March 2001

The French Embassy in Cameroon



www.mala.bc.ca/~earles/ nyos-feb01.htm

It will take 1 pipe15 years to de-gasNyos

There is alsonow a pipe

degassingManoun







Even bigger problemis Lake Kivu, Rwanda

Two thousand times biggerthan Nyos and two millionpeople live around its shores

svs.gsfc.nasa.gov/vis/a000000/ a002300/a002353/

CO2 and methane

www.ucl.ac.uk/geolsci/research/ sed-basin/introduc.htm

http://svs.gsfc.nasa.gov/vis/a000000/a002300/a002353/



http://www.ucl.ac.uk/geolsci/research/sed-basin/introduc.htm

http://www.ucl.ac.uk/geolsci/research/sed-basin/coresm.gif







Paleoecological evidencesuggests that Lake Kivu has

exploded at least 5 times

In January 2002, a volcano poured molten lava intoLake Kivu

Montrose Harbor Chicago




Lake Michigan 26 June 1954

Montrose Harbor, Chicago

From the Chicago Daily News:

BIG TIDAL WAVE HERE! Many Swept Into Lake; Fear 10 Killed

Three Bodies Already Found Mother of 11 Among Victims

3 Divers, Boats Hunt Others



25-mile-wide tidal wave

Witnesses claimed:

3 to 10 feet high

Many were swept off the

pier, 8 died

Supercharged surface seiche

C it l i t ' d th



Coroner cites algae in teen's deathBy DON BEHM, Sept. 5, 2003

After a yearlong investigation, the DaneCounty coroner has concluded that themysterious death of a Cottage Groveteenager last summer likely was the first inthe nation caused by exposure to a toxin

released by algae.

Another teen also was in the pond withRogers and later became sick, complaining

of severe diarrhea and abdominal pain. Hesurvived. Tests of blood and stool samplesfrom both boys found the common blue-green algae, known as Anabaena flos-aquae ,and its toxin, Anatoxin-a

http://www.whoi.edu/redtide/notedevents/bluegreen/bluegreen_9-5-03.html



Lake Peigneur, New Iberia,Louisiana

www.acadianmuseum.com/ annex.html

Lake has Jefferson Island, which has the“Rip Van Winkle Live Oak Botanical Garden”

5.3 km2 in surface area, but only 1-2 m deep

http://www.acadianmuseum.com/annex.html

http://www.acadianmuseum.com/annex.html



November 1980

Wilson Brothers Co. had

been hired by Texaco todrill for oil. Rig is out inthe middle of the lake

www.long-intl.com/company.htm

At 1,228 ft problems started….

The rig started to tilt



The lake was connected by the Delcambre Canal tothe Gulf of Mexico, twelve miles away

…and went down drain that had beenpunched in the bottom of the lake

The lake turned into a giant whirlpool…

So the water just kept flowing



A fifty foot waterfall (the highest ever to existin the state) formed where the canal wateremptied into the crater.

The ever-emptying lake caused the canal to lowerby 3.5 feet and to start flowing in reverse.

Within 7 hours, the lake was gone



Gone also were…

a second drilling rig

a tugboat

eleven barges from the canal

a barge loading dock

seventy acres of Jefferson Islandand its botanical gardens

the $5 million oil rig

What happened??



The lake was on top of a salt dome

Salt domes tend to be the home of salt mines

What happened??

Diamond Crystal Salt Mine

Texaco knew about the salt mine, they askedthe U. S. Army Corps of Engineers

The Corp contacted Diamond Crystal but….



Freshwater in a salt mine is a big problemwww.paul-deakin.freeserve.co.uk/ salt_mine.htm

the 50 mine workers all escaped

http://www.paul-deakin.freeserve.co.uk/salt_mine.htm






Seven lawsuits were filed, including:

Diamond Crystal sued Texaco for ruining its verylucrative mine (they got $32M in out-of-courtsettlement)

Texaco sued the salt company for not telling themwhere the mine was (they lost)

The drilling company (Wilson Bro) sued Texacofor the loss of their oil rig



Rip Van Winkle Gardens sued both Diamond andTexaco for the loss of buildings and plants, including

30,000 poinsettias ready to bloom for Christmas(got $12.8 M out-of-court settlement)

3 dogs died in the incident

Lake Peigneur is now 1,300 feet deep



Concepts to know

• What limnological processes resulted in

the the Lake Nyos gas disaster?

• How do surface sieches become killer?

15. killerlakes04

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