ICE WATER: RIVERS AND PERMAFROST (MODIFIED FOR ADEED)

ICE WATER: RIVERS AND PERMAFROST(MODIFIED FOR ADEED)

UNITE US ©2010 - 2012 Geophysical Institute, UAF Ice Water: Rivers and Permafrost

Overview:Rivers and streams that run through continuous and discontinuous permafrost areas are affected by changes in permafrost. Changes in water systems impact the surrounding ecology.

Objectives: The student will: • labelamapoftheYukonRiverdrainageidentifyingtributaries,communitiesandpermafrostregions;• useMicrosoftExceltographsalmonsurvivalrate;and• placetheimpactofpermafrostthawandsalmonsurvivalratesinaculturalcontext.

Targeted Alaska Grade Level Expectations: [10] SD1.2 The student demonstrates an understanding of geochemical cycles by describing their

interrelationships(i.e.,watercycle,carboncycle,oxygencycle).[9-11]SD2.1ThestudentdemonstratesanunderstandingoftheforcesthatshapeEarthbyrecognizingthe

dynamic interaction of erosion and deposition including human causes.

Vocabulary:biochemistry – the scientific study of the chemical composition of living matter and of the chemical

processes that go on in living organismscohesion –theactorstateofstickingtogethertightlydegrade – to lose its current physical conditionecosystem –anecologicalcommunitymadeupofplants,animalsandmicroorganismstogetherwiththeir

environmenterosion –thegradualwearingawayoflandsurfacematerials,especiallyrocks,sediments,andsoils,bythe

actionofwater,windorglacierfoothills – a hilly region at the base of a mountain rangegully – a trench originally worn in earth by running water and through which water often runs after rainshydrology –asciencedealingwiththeproperties,distribution,andcirculationofwateronandbelowthe

Earth’s surface and in the atmosphereice wedge –amassive,generallywedge-shapedbodyoficewithitstippointingdownwardlandslide –theusuallyrapiddownwardmovementofamassofrock,earth,orartificialfillonaslopemelt water – water derived from the melting of ice and snowrunoff – the portion of precipitation on land that ultimately reaches streams often with dissolved or

suspended materialsediment –thematterthatsettlestothebottomofaliquidormaterialdepositedbywater,wind,orglacierstalik –aRussiantermthatappliestoalayerofunfrozengroundbelowtheactivelayerandabovepermafrostthaw slump – slope failure resulting from thawing if ice-rich permafrostthermal –relatingto,orcausedbyheatthermo - erosional niche – the space created when ice-bearing permafrost is eroded by the thermal and

mechanical action of moving water.thermokarst –anyprocessofthermaldegradation(reductionintheamountofpermafrostthroughthawing)

or landscape change due to the thawing of permafrost or massive ground icetopography – the art or practice of graphic drawing in detail usually on maps or charts of natural and man-

made features of a place or region especially in a way to show their relative positions and elevationstussock –compacttuftespeciallyofgrassorsedge;alsoanareaofraisedsolidgroundinamarshorbogthatis

bound together by roots of low vegetationwatershed – a region or area bounded peripherally by a divide and draining ultimately to a particular

watercourse or body of water


ICE WATER: RIVERS AND PERMAFROST

Whole Picture:Despitevisionsofsandandsunassociatedwiththeworddesert,lowannualprecipitationcoupledwith

extremetemperaturesandpoordrainagemeansmostoftheArcticqualifiesasdesert.PermanentlyfrozengroundunderliestheArcticdesert.Ifthepermafrostthaws,thebehaviorofthesurfaceabovechanges.Runofffromsnowmeltorrainerodesmoreofthelandandcarriessedimentintoriversand,ultimately,theocean.Moreanddifferent sediment in the rivers and oceans may impact both freshwater and marine life. The biogeochemistry of theriversmaychangeduetotheinfluxoforganicmatterandmineralsbroughtbypermafrostthaw.Terrestrialecosystemswillbeaffectedalongwithaquaticandsub-aquaticsystems.Assurfacewaterhydrolologicalsystemstransitiontogroundwatersystemsduetothawingpermafrost,gulliesmaydevelopaswellaslandslides,thermo-erosional niches and slumps. The drying of the active layer will affect vegetation and wildlife and perhaps an increase in wildfires.

Inadditiontochanginglocalecosystems,thawingpermafrostmayhavebroaderimpact.Scientistsarecarefullyobservingjusthowpermafrostthawmaycontributetoglobalclimate.Becausefrozengrounddoesnotdecompose,therearevastamountsoforganiccarbonfrozeninthesoil.Thawingallowsdecompositiontobeginandreleasesstoredcarbon.CarbondioxideisagreenhousegasthattrapsheatinEarth’satmosphere.Withoutgreenhousegasestheplanetwouldbetoocoldforlife,butwithtoomuch,Earthcouldenteramuchwarmerclimatephase.

Effects of Permafrost Degradation on River Systems and HabitatsFrom “Impacts of permafrost degradation on arctic river biogeochemistry”byFreyandMcClelland.

The biogeochemical changes in river systems brought about by permafrost degradation may have farreachingeffects.Changesinwaterchemistrybroughtaboutbyanincreaseinminerals,organicandinorganic material and even increased flow of freshwater into oceans may alter environments. Scientists arestudyingthebiogeochemicaleffectsofdegradingpermafrostonhydrologysystemsintheArctic.PermafrostcurrentlyunderliessignificantportionsofthesixlargestArcticwatersheds(Ob’,Yenisey,Lena,Kolyma,MackenzieandYukon)inadditiontomanyothersmallerstreamsandriversenteringtheArcticOcean.Assuch,profoundimpactsmayoccurherewithpermafrostdegradation,includingbiogeochemicalcyclingwithinwatershedsandresultingdeliveryoforganicmatter,inorganicnutrients,andmajorionstotheArcticOcean.Atpresent,thereisconsiderableuncertaintyabouthowchangesinpermafrostmayimpactArcticriversandsubsequentlyoceans.Consequencescanbehighlycomplexandundoubtedlywillexhibitchangesspecifictoparticularsites.Factorsthataffectconsequencesofpermafrostdegradationinclude:typeofpermafrostthaw(wholesalethawing,drainingofthermokarstlakes,erosionofbanks)andenvironmentalcharacteristicsofwatershedssuchasvegetation,soiltypeandtopography.Regardlessoftheuncertaintiesinfuturepredictions,however,itisclearthatsignificantimpactsonbiogeochemicalcyclinginriverswilltranspirewithcontinuedwarmingandpermafrostdegradation.Scientistsemphasizethatfurthercollection of data at numerous sites is important to predict changes in river and ocean biogeochemistry.

Materials:• Clear pitcher• Icecubes,enoughtofillthepitcher• Clear plastic cups• Plasticspoon• Accesstowater• AccesstocomputersequippedwithMicrosoftExcelsoftware• Coloredpencils(varietyofcolors)• VISUALAID:“EffectsofRiverErosion”• VISUALAID:“PermafrostDistribution”• STUDENTINFORMATIONSHEET:“IceWater:RiversandPermafrost”• STUDENTWORKSHEET:“InHeartofAlaska:TheYukonRiverBasin• STUDENTLABSHEET:“SurvivalRateofSalmon”• STUDENTWORKSHEET:“BringingitHome”



Activity Preparation:Justpriortothestartofclass,fillaclearpitchercompletelyfulloficecubes.Addverycoldwatertofillthepitcher.Addverywarmwatertoaplasticcup.

Activity Procedure:1. Writetheword“erosion”ontheboard.Drawalineawayfromit,labelingitmechanical.Studentsarelikely

familiarwithmechanicalerosionthatoccursduetowind,water,ice(glaciers)andgravity.Reviewifneededthenwritethetermsunder“mechanical.”Explainstudentswilllearnaboutanothertypeoferosioncalledthermalerosion.Drawalineawayfromtheworderosionandlabelitthermal.Askstudentstodefinethermalanddescribetheprocessofthermalerosion.Wheremightthermalerosionoccur?Explainstudentswillfocustodayonhowthermalenergycontributestotheerosionthatoccursalongthebanksofriversand streams that meander through permafrost.

2. Showstudentsaclearpitcherfulloficewater.ThisrepresentsthewaterthatflowsinAlaska’sriversandstreams,whichisusuallyicecoldwaterfromsnowandglacialmelt.Pourwaterintoanemptycup,butdonotaddice.Usingthespoon,removeanicecubefromthepitcher.Showstudentsboththecupandtheice.Ask,“Whichiscolder?Howdoyouknow?”Thetwomaybeverycloseintemperature,butsincethewaterisliquidyouknowit’swarmer.

3. Scoopenoughicecubesintoaclearcuptoreachthetop.Showittostudents.Askastudentvolunteertopourwarmwaterovertheicecubes.Askstudentstowatchwhathappens.(Theicecubeswillmeltandshrink.)Explain:Thewarmwatercontainskineticenergy;thermalenergyalwaystranfersfromthewarmertothecooler,soheatfromthewateristransferringtotheice,causingittomelt.

4. HandoutSTUDENTINFORMATIONSHEET:“IceWater:RiversandPermafrost.”DisplayVISUALAID:“EffectsofRiverErosion,”pageone.Chooseareadingstrategybestsuitedfortheclassthenreadthroughpageone of the information sheet. Refer to the visual aid as you proceed. Remind students of the earlier demonstration.Theriverwateristransferringenergytothepermafrostcausingittothaw.Oncethawed,mechanical erosion carries away the debris and sediment.

5. DisplayVISUALAID:“EffectsofRiverErosion,”pagetwo.Askstudentstoturntopagetwooftheirinformationsheet.Again,readthroughthematerial,referringtothevisualaid.NOTE:StudentwillstudytheSelawikSlumpingreaterdetailinanotherUNITEUSlesson.

6. DisplayVISUALAID:“EffectsofRiverErosion,”pagethree.Askstudentstoturntopagethreeoftheirinformationsheet.Again,readthroughthematerial,referringtothevisualaid.Discuss,usingthefollowingquestions and prompts as needed:a. Describewhatyouseeinthisillustration.Whatishappeningtotheriverbank?b. Thereisalotofsedimentinthewater.Whydoesn’titwashaway?c. Whatmighthappentothesalmoneggsonthebottomoftheriveriftheygetcovered?d. Whatmighthappentotheplants?e. Thewaterisverymurky.Doyouthinkthesuspendedsedimentmightchangewherefishliketolive?f. Whatotherthingscanyouimaginemightresultfromthethawingofpermafrostalongthebank?

(Rivercouldgetwider,becomeshallower,eventuallychangecourse,etc.)

7. HandoutSTUDENTWORKSHEET:“IntheHeartofAlaska:TheYukonRiverBasin.”DisplayVISUALAID:“PermafrostDistribution.”Askstudentstocompletetheworksheet.(Leavevisualaidondisplayforstudentsastheycompletepageoneofworksheet.)Studentsmayneedassistancecompletingthemathproblemson page two. The problems are percentage equations.

Question4issolved:.001x5,000=5

Question5issolved:3,000÷.001=3,000,000



Answers: STUDENT WORKSHEET: The Heart of Alaska: The Yukon River Basin

1. b. about 33 percent2. continuous,discontinuous3. Answerswillvarybycommunity4. .001x5,000=55. 3,000÷.001=3,000,000

STUDENT LAB SHEET: The Life of a Salmon Egg

Ifstudentsfollowthedirectionstheyshouldendupwithachartthatlookssimilartotheoneshownbelow.

STUDENT WORKSHEET: Bringing it Home

Essayanswerswillvarybutshouldreflectanunderstandingofthelessoncontentandincludeinformationabout permafrost thaw and the potential effects of added sediment in the river.


EFFECTS OF RIVER EROSION

Athermo-erosionalnicheontheColvilleRiverDeltainAlaska.PhotocourtesyofJorgensonandOsterkampfrom Response of Boreal Ecosystems to Varying Modes of Permafrost Degradation.

The landslides in the photo at left occurredalongtheMackenzieRiver in an area that had been previously burned by a forest fire. TheMackenzieRiverDrainageisone of five major drainage systems oftheArctic.PhotocourtesyofGeologicalSurveyofCanada,NaturalResourcesCanada.

The photo at right shows the condition of a thaw slump on the SelawikRiverin2008.TheSelawikRiver is located in northwestern Alaska.PhotocourtesyoftheU.S.FishandWildlifeService.


EFFECTS OF RIVER EROSION


PERMAFROST DISTRIBUTION

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n

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rna

tio

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l P

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le,

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ssa

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s, U

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rvey

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nch

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ge,

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ska

, U

SA

A n

ew p

erm

afro

st m

ap of

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ska,

u

sin

g a

terr

ain-u

nit

ap

pro

ach

fo

r

map

pin

g p

erm

afro

st d

istr

ibu

tion

bas

ed on

cl

imat

e an

d su

rfic

ial

geo

log

y is

p

rese

nte

d

in

conju

nct

ion

w

ith

th

e N

inth

In

tern

atio

nal

C

on

fere

nce

on

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maf

rost

hel

d a

t th

e U

niv

ersi

ty o

f A

lask

a, J

une

29

to J

uly

3,

200

8.

Th

is m

ap

rep

rese

nts

th

e th

ird

ite

rati

on

of

a p

erm

afro

st m

ap f

or

Ala

ska,

foll

ow

ing t

he

circ

um

-arc

tic

per

maf

rost

m

ap

(Bro

wn

et

al

. 1

997

),

wh

ich

m

ade

min

or

mod

ific

atio

ns

to t

he

init

ial

map

by F

erri

ans

(1965

). T

o m

ap p

erm

afro

st,

we

dev

elop

ed a

ru

le-b

ased

mod

el (

see

colo

r-co

ded

tab

le)

that

in

corp

ora

ted m

ean

an

nual

ai

r te

mp

erat

ure

s (M

AA

T)

from

th

e P

RIS

M

clim

ate

map

an

d

the

surf

icia

l geo

log

y m

ap (

see

bac

k),

of

Kar

lstr

om

et

al.

(196

4).

We

use

d t

erra

in-

per

maf

rost

re

lati

on

ship

s d

evel

op

ed

by

Kre

ig

and

R

eger

(1

982

) an

d

ou

r k

now

l ed

ge

of

per

maf

rost

dis

trib

uti

on

to a

ssig

n p

erm

afro

st c

har

acte

rist

ics

to

each

su

rfic

ial

dep

osi

t u

nd

er v

aryin

g t

emp

erat

ure

s. S

urf

icia

l geo

log

y g

reat

ly

affe

cts

per

maf

rost

char

acte

rist

ics

bec

ause

of

dif

fere

nce

s in

top

ogra

ph

y,

soil

te

xtu

re

(wh

ich

af

fect

s m

ois

ture

an

d

ther

mal

p

rop

erti

es)

and

h

yd

rolo

gy

(su

rfac

e-w

ater

an

d g

rou

nd

wat

er).

We

mod

ifie

d t

he

surf

icia

l geo

log

y m

ap t

o

upd

ate

som

e ar

eas

wit

h n

ew in

form

atio

n (e

.g.,

eo

lian

lo

ess

and sa

nd,

and

gla

ciom

arin

e d

eposi

ts).

We

cod

ed t

he

per

maf

rost

map

wit

h s

urf

icia

l geo

log

y,

MA

AT

, p

rim

ary

soil

tex

ture

, p

erm

afro

st e

xte

nt,

gro

und

ice

volu

me,

an

d p

rim

ary t

her

mok

arst

la

nd

form

s. T

he

map

focu

ses

on

th

e to

p 1

0 m

of

per

maf

rost

, w

her

e p

erm

afro

st

can b

e m

ore

rea

dil

y m

app

ed f

rom

su

rfac

e fe

atu

res,

det

erm

ined

by s

imp

le f

ield

mea

sure

men

ts,

and

wh

ere

gro

un

d i

ce u

s ual

ly i

s m

ost

abu

ndan

t. D

istr

ibuti

on o

f p

erm

afro

st s

how

n o

n t

he

map

is

ther

efore

als

o b

ased

on

ou

r k

now

led

ge

abou

t

the

pre

sen

ce o

r ab

sence

of

per

maf

rost

wit

hin

th

e u

pp

er 1

0 m

. A

lth

ou

gh

we

use

d

rece

nt

MA

AT

in

ou

r ru

le-b

ased

m

od

el,

we

note

th

at

per

maf

rost

d

istr

ibuti

on

is

gre

atly

aff

ecte

d b

y p

ast

clim

ates

.

We

reli

ed on

m

any so

urc

es fo

r th

e ef

fort

b

ut

are

not

able

to

ci

te al

l re

fere

nce

s h

ere.

Th

e m

ain m

ap s

how

s p

erm

afro

st t

hic

kn

ess

val

ues

bas

ed o

n

Mac

Car

thy (

19

52

), B

rew

er (

19

58

), F

erri

ans

(1965

), P

éwé

(19

75

), O

ster

kam

p

and

Pay

ne

(19

81

), L

ach

enb

ruch

et

al.

(198

7),

an

d C

oll

ett

et a

l. (

19

89

). D

epth

s w

ere

det

erm

ined

b

y

tem

per

atu

re

loggin

g

or

inte

rpre

tati

on

of

ice-

bea

rin

g

per

maf

rost

fr

om

geo

ph

ysi

cal

dat

a.

Sou

ther

ly

site

s ar

e in

clu

ded

w

hen

th

e

pre

sen

ce of

per

maf

rost

is

ev

iden

t ev

en if

p

erm

afro

st th

i ckn

esse

s w

ere

not

det

erm

ined

.

Th

e fo

llo

win

g c

har

acte

rist

ics

are

show

n o

n s

mal

l th

emat

ic m

aps

on

th

e

rev

erse

sid

e of

the

mai

n m

ap:

Gro

un

d t

emp

erat

ure

s (u

sual

ly m

easu

red

at

dep

ths

20-3

0 m

) w

ere

ob

tain

ed

from

b

ore

hole

s b

y

V.

Rom

anovsk

y,

G.

Clo

w,

K.

Yosh

ikaw

a,

and

T.

Ost

erk

amp

as

par

t of

the

Th

erm

al

Sta

te

of

Per

maf

rost

p

roje

ct

for

the

Inte

rnat

ional

Pola

r Y

ear

(Bro

wn

and

Rom

anovsk

y 2

008

). O

nly

rec

ent

dat

a ar

e

use

d. G

rou

nd

ice

volu

mes

wer

e es

tim

ated

for

the

up

per

5 m

of

per

maf

rost

usi

ng

terr

ain

rel

atio

nsh

ips

esta

bli

shed

by K

reig

an

d R

eger

(1

98

2)

and

ou

r fi

eld

dat

a.

Gro

un

d i

ce v

olu

me

nea

r th

e su

rfac

e is

hig

her

in c

old

er r

egio

ns

du

e to

act

ive

ice-

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.,

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A.

&

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E.S

. 199

7.

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rian

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1965

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., H

op

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& F

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-35

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ale

1:1

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00

.

Kre

ig,

R.A

. &

Reg

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R.D

. 198

2. A

ir-p

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per

ties

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rv.,

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., S

ass,

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., L

aw

yer

, L

.A.,

Bre

wer

, M

.C., a

nd

fiv

e oth

ers.

1987

. T

emp

erat

ure

an

d d

epth

of

per

maf

rost

on

th

e A

lask

an A

rcti

c S

lop

e.

In:

Ala

ska

Nort

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lope

Geo

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lask

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So

c.,

Book

50

, V

ol.

2:

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5-

558

.

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Car

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G.R

. 19

52

. G

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s on

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Tra

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Am

er.

Geo

ph

ys. U

nio

n 3

3(4

): 5

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.

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T.E

. &

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ayn

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19

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836

, 145

pp.

Wal

ker

, D

.A.,

Wal

ker

, M

.D.,

Ever

ett,

K.R

. &

Web

ber

, P

.J.

198

5.

Pin

gos

of

the

Pru

dh

oe

Bay

reg

ion

, A

K. A

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lp. R

es. 17

: 32

1-3

36

.



Ice Water: Rivers and Permafrost

Alaska’sriversarecold.That’snotreallynewstoanyone.Afterall,they’refedbymeltingsnowandicyglaciers.ManyofthemwindthroughArcticlandsunderlainwithfrozenground,rightthroughthefragileArcticecosystem.Sowhathappensifthepermafrostbeginstothaw?Thingsbegintochange.

Erosion and Permafrost

Mostlargeriversdon’thavepermafrostunderthem,eveninthecontinuouspermafrostzone,butpermafrostisprevalentalongthebanksinthecontinuouszoneandoccursinthediscontinuouszoneaswell.Warmingtemperaturescancausepermafrosttothaw,whichcanleadtoincreasederosion.Thermo-erosionalniches,landslidesandthawslumpscanresultwhenafrozenriverbankbeginstothaw.

Thermo-erosional Niche

Athermo-erosionalnicheisformedwhentheriverundercutsthawedportionsofthebankandtheupperparts,whichmaybestillfrozen,causingthebanktocollapseandmelt.Thisleadstomassmovementofthebankdownslope.

Thermal and mechanical erosion

Thermo-erosional Niche

Erosion

Mechanical erosion: the process of weathering.

Windandwatercarrysedimentfromits source and deposit it somewhere else.Rain,snowmelt,glacialmelt,riversandstreamsallcontribute;sodoes gravity. The down-slope creep of soil and other material is under the force of gravity.

Thermal erosion: erosion caused by heat.

Eventhoughriverwateriscold,it’s still warmer than permafrost. Whenthewaterhitsthefrozenbank,itcausesittothaw.Afterthat,mechanicalerosiontakesover.

Athero-erosionalnicheontheColvilleRiverDeltaonAlaska’sNorthSlope.PhotocourtesyofJorgensonandOsterkampfromResponse of Boreal Ecosystems to Varying Modes of Permafrost Degradation.



Landslides

Landslidescanoccurwhenaslopeoffrozenlandmeetsconditionsthat cause it to thaw.

Extremesummertemperatures,drought(whichkillsvegetation),forestfires,erosionoftopsoil,andchangingclimateareamongthecatalysts.Aspermafrostthaws,thewetsoillosescohesionandeasilyslidesdownhill.Whenthisoccursalongariverbank,thedebrisisdepositedintotheriver.InonestudyoftheMackenzieRiverinCanadaresearcherscountedover2,000landslidesalongthe river route.

Thaw Slumps

Oneofthemostdramaticchangesthatcanoccurwhenpermafrostthawsisthedevelopmentofaretrogressivethawslump.Athawslumpoccurswhenslopedground—frozenforhundreds,maybethousands,ofyears—thaws,causingittocollapse.Thisexposesanewwalloffrozenmaterial,whichthenthawstorevealanotherone.Inthiswaythefeatureeatsitswayintoahillside.It’sasifsomeonetookagianticecreamscooptolandscape.Themuddydebristhenheadsdownhill,oftenintostreamsandrivers.

Why is This Important?

Thermo-erosionalniches,landslidesandthaw slumps can all deposit sediment into rivers. That sediment can change theriver,impactingtheecosystem.• Small sediment could fill the spaces

between the gravel on the river bottomwherefertilizedfisheggssettle to over-winter.

• Theinfluxofdebrisandsedimentcouldchangeariver’sbiochemistry,addingminerals,organicandinorganicmaterial,whichcouldaffectthehabitatofallthatrelyonit,includingfish,animals,insectsandplants.

• MostofAlaska’sriversandstreamsultimatelyempty into the ocean. Changes in river chemistry could mean changes in ocean chemistry.

TheillustrationtotherightshowstheYukonRiverdrainagearea.TheYukonRiverandall its tributaries empty into the Bering Sea. TheYukonRiverdrainageisunderlainwithcontinuous and discontinuous permafrost.


NAME: __________________________ THE HEART OF ALASKA: THE YUKON RIVER BASIN

PART 1

Directions: TheAlaskamapbelowhighlightstheYukonRiverdrainage.Useclassroomreferencematerial,theInternet,andotherresourcestofindanswers,thenplacethefollowinginformationonthemap.Whenfinishedcomplete the questions that follow.

• TracetheYukonRiveranditstributarieswith a blue colored pencil.

• LabeltheYukonRiverandfivetributaries.

• LabeltheYukonRiverDrainage.

• LabelatleastthreecommunitiesintheYukonRiverdrainage.Useareddottomarkthelocation.Writethename.

• LabeltheoceanintowhichtheYukonRiverdrains.

• Sketchtheapproximateboundaries of the state’s permafrostzonesthenlabeleachregion.Lightlyshadeifdesired.

1. TheYukonRiverdrainagecovers_______________________________________________percentofAlaska?

A. about50percent C. about10percentB. about33percent D. about80percent

2. Whattype(s)ofpermafrostunderlaytheYukonRiverBasin?Circleallthatapply.

continuous discontinuous sporadic isolated

3. Whatisthenameofyourcommunity?__________________________________________________________

IsitlocatedintheYukonRiverdrainage?___________________


NAME: __________________________ THE HEART OF ALASKA: THE YUKON RIVER BASIN

PART 2

Directions:Readthefollowingbackgroundinformation,thencompletethequestionsthatfollow.

Background: People and the Yukon

TheYukonRiverhasculturalandhistoricalsignificanceextendingbacktensofthousandsofyears.AnthropologistsspeculatetheYukonValley may have been the main immigration route for NorthAmerica’sfirstpeople.

TheYukonRiverhasthelongestsalmonmigrationofanyriverintheworld.Alaska’sIndigenouspeople have depended on the river’s salmon harvestformorethan10,000years.Stilltodaypeople set up fish camps with fish wheels and nets each summer and enjoy the bounty of the river,whichisnotonlyanimportantsourceofsubsistence food but a cultural cornerstone.

Salmon and the Yukon

Changesinthebiochemistryoftherivercouldhaveasignificantimpactontheriver’ssalmonpopulation,whichwould impact the subsistence lifestyle of those who depend on the salmon run. Scientists are concerned that sediment from permafrost thaw could smother salmon eggs deposited in the gravel at the river bottom.

4. Undernormalcircumstances,onlyabout.001percentoftheeggslaidinagravelbedwillreachmaturityatseaandreturntospawninggroundstostartthecycleagain.Of5,000eggs,howmanywillsurvive?

Answer:___________________

5. Remember,onlyabout.001percentofeggsreachmaturity.Ifonefishcampcatchesthendriesorfreezes3,000salmontoprovide12familieswithfishforthewinter,howmanysalmoneggshadtobedepositedtoprovidethe3,000fish?

Answer:___________________

The female salmon uses her tail fin to create a shallow depression in the gravel at the bottom of theriver.Initshelaysupto5,000eggs,whicharethenfertilizedbythemale.Thefemalecoverstheeggs with gravel and moves to another area to lay more eggs. She may do this up to seven times.


NAME: __________________________ SURVIVAL RATE OF SALMON

Directions:Usingthehypotheticaldataprovided,useMicrosoftExceltocreateaspreadsheetthatdescribesthefateofonebedof5,000salmoneggs.Followthestepscarefully.

STEP 1: OpenanewMicrosoftExcelfile.Saveitas<YourName>SalmonStudy.

STEP 2: Usethefilenameasthespreadsheettitle.TypeitincolumnA,row1.

STEP 3: Inrow2,undercolumnA(cellA2),typeEggs at Start.IncolumnB(cellB2),type5,000.

STEP 4: Fillintheremainingdatafromtheinformationbelow.Abbreviatephraseswhenneeded.ThedescriptiongoesincolumnA,thenumberincolumnB.

Outof5,000eggs,500didnotgetfertilizedsotheydied.Ariverboatdroppedanchor,knocking50 eggs free of the gravel. Sediment eroding fromtheriverbankwashedoverthegravelandsuffocated1,000.Uponhatching,300alevinsweretooweaktosurvive.Largerfishintheriverate 500 young fry. Birds snatched 41 fry from the river.Afterbecomingtrappedinashallowpool,260 smolts died from becoming overheated. During the years spent growing in the ocean 1,550ofthesalmonwereeatenbybiggerfish,95weregobbledupbyseals,and196werecaughtbysportfishermen.Oncetheyheadedbackuptheriver,bears,ottersandotherlandmammalsate80salmon.Afishwheelharvested410.Beforereachingthespawningground,10diedfromexhaustionand3werecrushedagainstrockstryingtojumpawaterfall.Oftheoriginal5,000,only5madeitalltheway.

Yourspreadsheetshouldlooksimilartotheone at right.

Hint:Youcanmakethecolumnwider by sliding the boundary line to the right.

Hint:Don’tforgettoclick“Save”often!


NAME: __________________________ SURVIVAL RATE OF SALMON

STEP 5: Nowmakeagraphfromthedata.Highlighttherowsthatbreakdownthefateoftheeggs.ExcludetherowthatsaysEggs to Start,andstartat row 3.

STEP 6: ClickontheChartWizardfunctionlocatedonthetoolbar.Itlookslikethis:

STEP 7: Select Doughnutchart,thenchoose the option that shows the doughnutbrokenoutinsections.

STEP 8: ClickNext >.

STEP 9: ClickNext >againwhenaskedabout data range.

STEP 10: Give your chart atitle.Youcanuse the same titleasinrow1,or use a shorter version.ClickNext > again.

STEP 11: Choose to keepyourchart within the current page of your spreadsheet. MakesuretoclickAs new sheet:thenclickFinish.

Anothertabwillopenthatshowsavisualbreakdownofapossiblesalmonlifescenario.Besuretosaveyourfile!


NAME: __________________________ BRINGING IT HOME

Directions: Basedontheinformationyouhavelearnedfromtheworksheet,TheHeartofAlaska:TheYukonRiverBasinandthelabsheet:SurvivalRateofSalmon,addressthescenario:

Scenario

YourcommunityislocatednearariverintheYukonRiverbasin.Thepeopleinyourcommunitydependonsalmonandotherfishintheriverforsubsistence.Onarecentmotorboattripuptheriveryounoticedseveralsmalllandslidesandthebeginningsofwhatcouldbeathawslump.Youareconcernedandwishtosharewhatyouknowwithcommunityleaders.Whatwouldyoutellthem?Includewhatyouknowaboutpermafrostthaw,thesedimentit could add to the river and the survival rate of salmon.

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

_______________________________________________________________________________________________

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_______________________________________________________________________________________________

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Documents

ICE WATER: RIVERS AND PERMAFROST (MODIFIED FOR ADEED)