scientific ocean drilling: accomplishments and challenges

7/30/2019 Scientific Ocean Drilling: Accomplishments and Challenges

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WHAT IS SCIENTIFIC OCEAN DRILLING?.........................................................................................2

CYCLES OF THE SOLID EARTH.........................................................................................................4

Earths Magnetic Field .........................................................................................................................4

Continental Breakup and Sedimentary Basin Formation ......................................................................5

Structure, Composition, and Formation of the Ocean Crust ................................................................5

Subduction Zone Processes and Seismogenic Zones ........................................................................6

Large Igneous Provinces ....................................................................................................................7

FLUID, FLOW, AND LIFE ON THE SUBSEAFLOOR.............................................................................8

Heat Flow, Fluid Flow, and Geochemistry............................................................................................8

Hydrothermal Vent Processes .............................................................................................................9

The Subseafloor Biosphere ...............................................................................................................10

Gas Hydrates ...................................................................................................................................11

EARTHS CLIMATE HISTORY ..........................................................................................................12

Past Warm Climate Extremes and the Greenhouse World .................................................................12

Cenozoic Ice Sheet Evolution and Global Sea Level Change.............................................................13

Orbital Forcing ..................................................................................................................................17

Abrupt Climate Change ....................................................................................................................18

Co-Evolution of Life and the Planet ...................................................................................................18

ASSESSMENT OF THE 2013-2023 SCIENCE PLAN .......................................................................21


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The U.S.-operated JOIDES

Resolution is a multipurpose

drillship that serves the

international scientic ocean

drilling community. Credit:

William Craword, IntegratedOcean Drilling Program U.S.

Implementing Organization

(IODP-USIO).

A rich

history oEarths past lies

beneath the ocean.The sediments and rock o the ocean foor contain records o active

biological, chemical, and geological processes that have shaped the

Earth over millions o years.

Scentc ocen rn hs spurre remrkbe proress n unerstnn mny ob

processes: conrmn the theory o pte tectoncs, ocumentn the hstory o Erths c-

mte system, nvesttn the roe o fu fow wthn the ocen crust, n scovern n

extensve subsefoor bosphere tht my we nhbt o the wors ocenc sements

n much o the pnets crystne crust.

Ths booket summrzes the nns o the Nton Reserch Counc report, Scientifc

Ocean Drilling: Accomplishments and Challenges. The report ooks t sncnt ccom-

pshments enbe by scentc ocen rn n so ssesses the potent or trnsor-

mtve scoveres bse on the reserch escrbe n Illuminating Earths Past, Present

and Future: The International Ocean Discovery Program Science Plan or 2013-2023,

scence pn or the next ece o scentc ocen rn.


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2

What is Scientic Ocean Drilling?

The ocen foor hos vst recor

o Erths hstory. The bs-

tc rock tht mkes up most

o the sefoor hos eo-

chemc cues bout pro-

cesses wthn Erths nteror.

Sements eposte bove

the rock prove normton

bout contons tht exste when

they were own. Unke sements

on n, whch cn be tere or even com-

petey remove throuh the ctons o

wn, wter, n tectoncs, sefoor sementshve rey been preserve n contnuous,

unsturbe yers.

Scentsts ccess ths recor o Erth

processes throuh scentc ocen r-

n, whch ows them to recover cores

on cynrc smpesrom the

sefoor. The rock n sements re

nyze n reserch borto-

res n rchve n repos-

tores or uture stuy.

Ocen rn so en-

bes reserchers

Scientists prepare a CORK or deployment.

Credit: William Craword, IODP-USIO.

to coect subseoor us n mcrobes,

s we s eophysc n eochemc

t, rom the borehoes et behn when

core s extrcte.

Put a CORK in it!

Every scentc ocen rn hoe proves

scentsts wth opportuntes or scovery.

Trtony, ths hs been throuh nyss o

the core extrcte rom the ocen foor. Some

hoes prove ton opportuntes to mon-

tor contons such s temperture, pressure,

n fu fow n the subsefoor throuh pce-

ment o sensors n the borehoe. The process o

coectn t rom borehoes s compcte

by the ct tht rn cn sturb ntur con-

tons n resut n exchnes between se-

wter n fus wthn the rock or sement.

To ow prmeters such s temperture

Global distribution o drill holes and sampling sites rom scientic ocean drilling

programs between 1968 and 2011. Credit: IODP-USIO.


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The following steps explain how an ocean drilling core iscollected aboard the drillship and prepared for use by

researchers.

1. The drill string is assembled and lowered throughthe moon pool, an opening in the ships hull to the water

below.Aspecicdrillbitischosenbasedontheproperties of the sediment or rock that is being drilled.

2. Once the core is extracted and brought back up to the rig oor,technicians carrythecoretothecatwalk,labelit,and

cut it into 1.5 meter (about 5 feet) sections.

3. Scientists analyze physical properties of the core, such asdensity, porosity, and magnetism.

4. The core is split lengthwise into two halves: the workinghalf, which scientists sample for use on board the drillshipand back in their laboratories; and the archive half, whichis kept unsampled for future comparison. Scientists

document the core in detailincluding its composition,grain size, and colorand take photos of the core forresearch purposes.

5. Scientists identify sections they want to sample on ship orstore for post-cruise research in their own laboratories.

6. Both halves are stored in refrigerated space in the shipshold. At the end of the cruise, the cores are stored in an

onshore repository under controlled conditions forfuture use.

Core on DeCk!

CORKs (Circulation Obviation Retrot Kits) are devices that

seal boreholes o rom seawater, more closely mimicking

the natural subseafoor environment. CORKs can be used

or pressure, seismic, strain, and temperature monitoring;

fuid sampling; and microbiological and perturbation experi-

ments. Credit: Modied rom Fisher et al., 2011.

n pressure to return to norm,

scentsts hve eveope CORKs

(Crcuton Obvton Retrot Kts)

evces tht se borehoes o rom

sewter, more cosey mmckn

the ntur subsefoor envronment.

Recenty, scentsts hve eveope

vnce CORKs tht cn se mu-

tpe seprte zones wthn sne

borehoe, corresponn to strtcton

oun wthn the sefoor.

Top right: Scientists careully split a rozen core section.


Bottom right: A technician helps carry a core rom the drill foor

to the catwalk. Credit: William Craword, IODP-USIO. 3


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4

SCiENTiiC OCEaN dRilliNg hs ven

reserchers better ccess to the Erths nte-

ror to better unerstn so Erth cyces

the processes tht enerte n moyErths crust. Over the st our eces, new

scoveres hve prove mportnt nshts

nto pte tectoncs, the process o contnent

rtn, the Erths mnetc e, the rchtec-

ture o ocen crust, n the processes tht

enerte mjor erthqukes n tsunms.

Earths Magnetic Field

deep wthn the qu outer core, the mo-

ton o moten ron oys enertes Erths

mnetc e. Over on tme sces, Erthsmnetc e swtches recton, cus-

n the mnetc poe to mrte

rom north to south n bck

n. Evence o these re-

verss s recore n ron-

bern mners tht

re bunnt n the

rocks tht mke

up the ocenc

crust. Ocen

rn hs owe reserchers to use the

mnetc propertes o these rocks to trce the

hstory o sefoor ormton over eooc tme.

The Theory o Seafoor Spreading

One o the rst mjor chevements o sc-

entc ocen rn ws the conrmton o

sefoor spren. Ocen rn owe

reserchers to coect sement smpes n

trnsect cross the M-atntc Re nthe South atntc Ocen. By ookn t m-

croscopc ornsms wthn sement recty

bove the ocenc crust, reserchers scov-

ere tht the e o the sements ncrese

wth stnce rom the re crest. Sement

e so correte we wth the pre, -

terntn mnetc sntures (corresponn

to reverss n Erths mnetc e) tht were

recore n the rocks s they spre wy

rom the m-ocen re. Ths ccompsh-

ment prove to be the ynchpn or estbshn

the prm o pte tectoncs,whch toy

serves s the ounton or unerstnnErths processes.

Generating a GeologicalTime Scale

Scentc ocen rn t ws essent

or corretn chnes n mnetc ntensty

Thin section o a basalt with olivine crystals, viewed under cross-polarized light.

Credit: IODP-USIO.

CyCles of the solid earth


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n orentton wth te mrne mcroos-s recors o versty, bunnce, n eo-

chemstry. When combne wth stronomc

cbrton, these sprte es o stuy con-

trbute to the eveopment o precse eo-

oc tme sce extenn 150 mon yers

nto the pst. Contnue renements usn

oby strbute smpes n ncresny

precse tn toos hve me the tme sce

n nspensbe too or etermnn the rtes

o mny o Erths processes, both on n

n n mrne systems.

Continental Breakup and

Sedimentary Basin

Formation

The process by whch contnents brek prt

n ntte sefoor spren hs been key

queston or sever eces. Throuhout

Erths hstory, contnent brekup hs usu-

y been ccompne by the eveopment o

new ocen crust foor between the rte con-

tnents, yet the compex trnston between

contnent n ocenc crust s st poory

unerstoo. in ton, sementry bsns

Petrologists work in the core lab. Credit: William Craword, IODP-USIO.

on the mrns cn ho hyrocrbon re-

sources o economc mportnce.

as ery s the m-1970s, ocen rn es

were exmnn the eometry o nt rment-

ton o crust t erent types o contnent mr-

ns. Scentsts me the scovery tht yers

o vocnc rock on the mm-rch Northest

atntc mrns were erupte on n, rther

thn unerwter s h prevousy been hypoth-

esze. at mm-poor mrns on the cost

o Spn n Newounn, upper mnte rocks

seprte contnent crust rom ocenc crust.

in combnton wth other pproches, scentc

ocen rn contrbute to unerstnn the

processes o contnent brekup, semen-

try bsn n hyrocrbon ormton, n

creton o new sefoor.

Structure,

Composition, andFormation o the

Ocean Crust

drn s the ony rect meth-

o to nvestte the orm-

ton, structure, n compo-

ston o the ocenc crust

n r upper mnte (to-

ether ce the ocenc

thosphere). Ery motvton

or rn the ocen crust

ocuse on unerstn-

n ts yere structure.

A core ready or analysis.

Credit: IODP-USIO.

5


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6

Subduction Zone

Processes andSeismogenic Zones

gret ntur hzrs such s vocnoes,

erthqukes, n tsunms cn be ener-

te t subucton zones, where two tectonc

ptes coe n one escens beneth the

other. Scentc rn expetons hve -

owe reserchers to probe the propertes o

subucton zones, eepenn the scentc

unerstnn o contons tht trer these

eooc hzrs.

Subduction Zone ProcessesThrouh scentc ocen rn, scentsts re

be to coect smpes ner subucton zone

bounres to hep etermne the nture o the

crust, sements, n fus n these reons.

These mters hve stnctve compostons

n cn ct s trcers or processes ento vocnc eruptons. Over tme, stues hve

evove rom smpy entyn these trcers to

constructn comprehensve moes tht hep

to unerstn the bnce o mters fown

nto n out o subucton reons.

Seismogenic Zone Experiment

Recenty, new scentc ocen rn n-

ttve, the Sesmoenc Zone Experment

(SEiZE), hs been ntte. its objectve s to

r throuh subucton zone bounry n

orer to expore the mechncs o re m-

ntue erthqukes (8.0 or reter) usn the

Whe nt eorts were hmpere by the

technc cutes o rn nto rock, whch

pose chenes or methos eveope to

r soter sements, enneern nnovtons

hve mprove hr rock rn cpbtes.

Ocen rn cores hve been use to conrm

the e o the oest ocenc crust, whch ws

orme bout 180 mon yers o. Becuse

t s much youner thn the e o the Erth,

ths scovery urther supporte the concept

tht ocenc crust crete t m-ocen res

s eventuy recyce t subucton zones.

Premnry observtons o r cores suest-

e tht the structure n composton o oce-

nc thosphere re erent, epenn on the

spren rte o the m-ocen re where

t s orme. urthermore, rn t

tectonc wnows (reons where

rocks tht re usuy eep n

the Erth hve been brouht

to the sefoor throuh

tectonc processes) hs

owe scentsts to

stuy both ower

crust n upper

mnte rocks.

A petrologist studies cores o oceanic crust.

Credit: John Beck, IODP-USIO.


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7

Jpnese rser rn vesse Chkyu. int

eorts ocuse on the Nnk Trouh o the

cost o southestern Jpn, n re wth

on hstory o re erthqukes n ev-

sttn tsunms. an upcomn expeton

w ocus on the octon o the ret Tohoku

erthquke o Mrch 2011.

History o Arc Volcanism

Scentsts hve ne new nsht nto the

hstory o vocnc rcs by stuyn yers o

vocnc sh preserve n ocen sements.

Cores extrcte rom the Mrn-izu rc n the

Western Pcc Ocen yee nery com-

pete 45 mon-yer recor o rc vocnsm,

provn nsht nto how the rc evove over

tme. Other sh stues, rom cores obtne on

the Crbben Pte, ocument the epsoc n-

ture o exposve vocnsm n Centr amerc

n ncte tht some vocnc eruptons n ths

reon rv the rest super-eruptons n the

eooc recor.

Large Igneous Provinces

lre neous provnces orm when mssve

outpourns o bstc v occur over eo-

ocy short tme peros (2-3 mon yers),

cretn sncnty thcker thn norm ocen

crust. lre neous provnces n the ocen re

enery rete to mnte pumes or hotspots

n cn cover tens o thousns o squre ko-

meters. Ther ormton nfuences ocen chem-

stry n cmtc contons, n cn even -ect speces extncton n evouton.

Becuse re neous provnces re so thck

n re oten bure beneth mrne se-

ments, smpn them presents sncnt

chene. our submrne re neous prov-

nces hve been re to te, wth cores

rechn tens to hunres o meters nto the

vocnc rock. Peces o woo n sement

bure n the v revee tht the Kerueen

Pteu n the southern inn Ocen wsonce bove se eve, whe rn on the

Pcc Ocens Onton Jv Pteu suest-

e t orme entrey beneth the se surce.

By tn r cores rom the North atntc

Vocnc Provnce, scentsts were be to cor-

rete the tmn o the erupton tht crete

tht re neous provnce wth the Peocene-

Eocene Therm Mxmum (PETM), pero o

rp ob wrmn bout 55 mon yers

o. Ths correton n tme sueste

connecton between mssve vocnc

eruptons n the chnes n cmte, mss

extnctons, n ocen nox events thtoccurre t the PETM.

Global locations o large igneous provinces. Credit: Modied rom Con et al., 2006.


10/28

8

Heat Flow, Fluid Flow, andGeochemistry

The sce n mportnce o fu fow throuh

ocen crust cnnot be unerestmtethe

voume o fu fown throuh the ocenc

crust s o the sme orer o mntue s the

mount o wter entern the ocen rom

the wors rvers. However, unt recenty, tte

ws known bout the pthwys o het n

fu throuh the subsefoor. Scentc rn

proves wnow on the mny chemc, tec-

tonc, booc, n eophysc processes

nfuence by the nterctons between wter

n rock. These ncue the mntue n

strbuton o fu pressures, the enerton o

exposve vocnsm, the ormton o hyrtes

n mner resources, n the strbuton o

mcrob communtes. in ton, scentc

ocen rn hs spurre the eveopment

o new smpn technooes n on-term

mesurements tht hep reserchers montor

rtes n ptterns o fu fow.

Fluid Flow Through BasementRock

in ery experments, scentsts notce tht

sewter ppere to be rwn own nto the

fluids, flow, and life

Beneath the oCean floor

BENEaTH THE SEalOOR, ntur pumb-

n system ows fus to crcute throuh

the ocen crust. These fus remove het rom

Erths nteror, ter the chemstry o the bse-

ment rock, n nfuence the strbuton o m-

crobes n the subsurce bosphere. The bty

to r eep nto the sefoor hs ncrese our

unerstnn o the roe o fu fow wthnocen sements n bsement rock, espe-

cy how hyroeooc systems re con-

necte wthn the ocen crust. Ths hs e to

chevements n unerstnn how rock n

fus nterct, how hyrotherm vent systems

crete sefoor mner eposts, n how s

hyrtes re orme. By provn the ony c-

cess to the subsefoor bome, scentc

ocen rn hs so revoutonze

unerstnn o subsurce m-

crob communtes vn t the

mts o e.

Microbes that colonized chips o

basalt placed in a borehole

are visualized using green and

orange fuorescent dyes.

Credit: Beth Orcutt, BigelowLaboratory or Ocean

Sciences.


11/28

9

upper eves o bst throuh r hoes. Ths

ncte tht ocenc crust ws more perme-

be thn the sement yers bove. anyss

o ocen rn cores conrme ths hypothe-

ss, shown tht show bsement rock s con-

sstenty three to seven tmes more permebe

thn the sement eposte bove. urther

stues o rock cores emonstrte tht bse-

ment rock becomes ess permebe t reter

epths beow the ocen foor. The wespre

nture o re-sce fu crcuton throuh

bsement rock hs mpctons or subsefoor

mcrob communtes n or the exchne o

chemcs n het throuh the ocens.

Hydrothermal Vent

Processes

Sewter enters ocenc crust ner m-

ocen res throuh rctures n the rock.

as t penetrtes more eepy nto the crust,

the sewter rects wth the hot bsement

rock n exchnes chemc eements.

Mnesum, or exmpe, s bsorbe nto

the rock, whe

ron, znc, mn-

nese, n copper

re reese nto the fu.

The cc, mner-rch fu be-

comes buoynt n schres t the sefoor.

Chemcs n the hyrotherm fu prove

enery to support ecosystems teemn wth

exotc vretes o shrmp, cms, tubeworms,

n other cretures.

Unt the vent o ocen rn, the ony wy

to stuy the chemc rectons beneth hy-

rotherm vents ws by coectn the fus

emntn rom vents, exmnn rocks rom

the sefoor surce, or stuyn ophotes

rments o ocen crust tht hve been

thrust onto contnents by cosons between

ocen n contnent ptes. Stuyn cores

obtne throuh scentc ocen rn hs

me crtc contrbutons to unerstnn

the chemstry, eooy, n booy o hyro-

therm vents n ther roe n the composton

o ocen crust n ocen chemstry.

Mineral Deposits

One o the more unexpecte outcomes o

rn t hyrotherm stes hs been the s-

covery o mssve sefoor n subsefoor

mner eposts. drn nto re epost

A thin sliver o pyrite

(iron sulde) rom a

hydrothermal mound on

the Mid-Atlantic Ridge.

Credit: IODP-USIO.

Microbiology samples are collected rom a sediment core.

Credit: John Beck, IODP-USIO.


12/28

10

hve ente mcrobes t ever reter

epths, even nn them n sements co-

ecte t reter thn 1,600 meters beow the

sefoor ner Newounn. Bse on the v-

rety o mcrob e observe so r, scentsts

estmte tht the number o mcrobes vn n

just the top 500 meters o sefoor sement s

equvent to 10 percent o the bomss tht

ves on Erths surce.

Lie Within Earths Crust

Whe most normton on subsurce mcro-

b communtes hs come rom sement

cores, n the te 1990s, scentsts becme

ntereste n mcrob ctvty n the bstc

ocen crust. The ocen crust beneth thesement s potenty the rest hbtt on

Erth, s the voume o ocen crust cpbe

o sustnn e s comprbe n mntue

to the voume o the wor ocen. Ocen r-

n core smpes show tht mcrobes py

n mportnt roe n tern bst rock n

A microbiologist works on core samples in an anaerobic chamber to prevent contamination.


ner the M-atntc Re revee most 3

mon tons o sue. at Me Vey, octe

n the northest Pcc Ocen, scentsts oun

subsurce epost o most 16 percent cop-

per ore. These nns hve enerte nterest

n mnn subsefoor hyrotherm systems,

but there s st much to be erne bout the

ormton n evouton o these eposts.

Thereore, communcton between scentsts

n nustry w be neee to vo potent

envronment me rom ocen foor mnn.

The Subseafoor

BiospherePeope hve on known tht the ocen

hrbors verse rry o speces, but

the mcrob e tht thrves beneth the

sefoor s much more recent scov-

ery. Scentsts rst ente subse-

foor e n 1955, when bcter

were scovere n mrne

sement cores re

7.5 meters beneth

the sefoor. Snce

then, reserchers


13/28

11

exchnn nutrents between sewter n

the crust. Sever recent scentc expetons

hve ocuse on rn nto bst n usn

CORKs s subsefoor mcrob observto-

res to exmne the unque bosphere present

wthn the bsement rock.

Gas Hydrates

at the hh pressure n ow tempertures

o the eep ocen, ses such s meth-

ne n crbon oxe cn combne wth

sewter to orm n ce-ke crystne

substnce ce s hyrte. Methne hy-

rtes re most oten oun t contnent

mrns, where they re sometmes concen-trte enouh to be consere s potent

enery resource (thouh there re presenty

no methos to economcy extrct them).

Hyrtes re so o nterest becuse scen-

tsts thnk tht the ntur reese o meth-

ne, potent reenhouse s, rom hyrtes

What Can Deep -Sea

MiCrobeS tell US

aboUt the liMitS

of life?

Themicrobesthatdwellbeneaththeseaoor

live in some of the harshest conditions on Earth.

Light cant penetrate to these depths, so most

energy comes from chemical compounds

leached from rock. Deeper beneath the ocean

oor,nutrientsbecomemorescarceandtemperature increases. Understanding how

deep-dwelling microbes can survive at

these depths could help scientists learn

more about the limits of microbial life,

the role of marine microbes in essen-

tial biogeochemical cycles, and the

origin and evolution of life

on Earthand perhapsother planets.

cou poten-

ty contrbute

to cmte wrm-

n. Scentc rn

hs pye mjor roe

n mprovn unerstnn

o the strbuton o s hyrtes

n ocen sements, s we s hyrte

behvor n stbty uner erent temperture

n pressure remes.

Developing Technologies to StudyGas Hydrates

at tmospherc pressure, s hyrte s stbe

ony t tempertures beow -80 C. Thereore,

much o the s hyrte n ocen rn

cores s ost s the core s brouht to the sur-

ce. The scentc ocen rn communty

poneere new technooes, such s the pres-

sure core smper, or recovern n nyz-

n s hyrte eposts t ntur, hh pres-

sure contons.

A chunk o gas hydrate recovered about 6 meters below the seafoor along the

Cascadia margin. Credit: IODP-USIO.

Top Let: This scanning electron microscope image shows microbes that colonized

chips o pyrite placed in a borehole on the Juan de Fuca Ridge fank or 4 years

(2004-2008). Credit: Beth Orcutt, Bigelow Laboratory or Ocean Sciences.

Bottom let: Communities o subseafoor microbes grow on polished chips o basalt

and pyrite placed into a CORK. The microbes can then be visualized using scanning

electron microscopy or fuorescent dyes (above and page 8). Credit: Beth Orcutt,

Bigelow Laboratory or Ocean Sciences.


14/28

12

sheet rowth n copse, s we s ob

se eve fuctutons o up to 120 meters, re-

mns one o the most unment scover-

es o scentc ocen rn.

Past Warm Climate

Extremes and the

Greenhouse World

More thn 3 mon yers o, cmtes were

enery wrmer thn toy n the tmo-

sphere contne hher crbon oxe eves.

By stuyn wrm cmte extremes recore

n ocen sements, scentsts cn ern how

the Erth system respone to peros o e-

evte reenhouse s eves n the pst.

Developing a Timeline o PastTemperatures

Ocen rn recors hve mprove estmtes

o Erths cmte senstvty to hher eves o

reenhouse ses n to short-ve perturb-tons n the crbon cyce. They hve so hepe

scentsts etermne the senstvty o ce sheets

to eevte reenhouse s concentrtons.

Se surce tempertures reconstructe rom

r cores emonstrte tht the ery Eocene

earths Climate historyTHE SEalOOR HOldS eooc rchve

o Erths cmte hstory tht extens or tens

o mons o yers, provn crtc nshts

nto the ptterns n processes o pst cmte

chne. Ths normton proves reserch-

ers wth recors o ntur vrbty nst

whch present n uture cmte chne cn

be compre.

as the enth n quty o scentc ocen

rn recors hs mprove, they hve

contrbute to unerstnn rmtc n

contnuous chnes o the Erths cmte

over the pst 100 mon yers, rom co

peros wth mssve contnent ce

sheets to extreme wrm peros

when por reons were

ce-ree. The entcton

o orbt cyces tht

nfuence repete

cyces o por ce

This thin section o limestone contains numerous shell ragments and small pieces

o volcanic glass that can provide inormation about past climate conditions.

Credit: IODP-USIO.


15/28

13

Epoch (rom 55 to 48 mon yers o) h the

wrmest cmtes o the pst 65 mon yers,

n tht the wor ws wrmer by bout 10 to

12 C. Cores recovere rom scentc ocen

rn so show tht hh ttues recte

more strony to ncreses n tmospherc

crbon oxe thn res coser to the equtor.

Observtons o pst peros o extreme

wrmth re mportnt becuse they hep

shrpen the perormnce o cmte moes nresponse to hher eves o tmospherc cr-

bon oxe.

Cenozoic Ice Sheet

Evolution and GlobalSea Level Change

Chnes n se eve refect how ce sheets n

the antrctc n the Northern Hemsphere

hve rown n shrunk over tme. Stues

Scientists sample layers o sediments rom cores extracted o the

Antarctic coast. Analysis o these samples will help scientists understand

changes in ocean temperature, sea ice extent, and primary productivitythroughout the last 12,000 years. Credit: Rob McKay, Victoria University

o Wellington.

proxy reCorDS in

SCientifiC oCean

Drilling

Scientistsusedierentcomponentsofmarine

sediments as climate proxiesindicators of

past climate and ocean conditions. For

example, variations in the types of fossilized

plantandanimalspeciesfoundinseaoor

sediment can indicate past changes in environ-

mentalconditionsataspeciclocation.Fossils

can also indicate the age of the various sediment

layers, helping scientists determine when environ-

mental changes took place. Geochemical

measurements of fossilized shell material can

provide insight into past oceanographic conditions,

such as temperature, salinity, pH, and the concen-

tration of atmospheric carbon dioxide. Combining

physical measurements of past temperatures withchemical measurements indicating atmospheric

carbon dioxide concentrations has been

particularly valuable for understanding how the

climate system responds to changes in atmospheric

carbon dioxide levels.

Photomicrographs o oraminiera, single-celled marine organisms that produce

calcite or aragonite shells. The shells can be used as climate proxies and can provide clues to

past ocean ecology and biogeography. Credit: Mimi Katz, Rensselaer Polytechnic Institute.


16/28

14

o sement cores ccesse throuh ocen

rn hve revoutonze unerstnn o

Erths cmte system urn the CenozocEr (65.5 mon yers o to the present),

n hve mprte new nshts nto the be-

hvor o por ce sheets n ther nfuence

on ob se eve. Becuse the behvor o

ce sheets n the ob cmte system n

wrmn wor s currenty not we uner-

stoo, ocen rn recors cn prove

nos tht hep mt the uncertnty roun

projectons o uture se eve rse.

Understanding Polar Ice Sheets

Scentc ocen rn pye n nter roe

n unerstnn the ntton o antrctc

cton, whch mrke Erths trnston

rom wrmer to coer cmte system.

Cores coecte rom the antrctc contnen-

t she bout 40 yers o prove the rst

evence tht contnent cton extene

bck to the Eocene-Oocene bounry (33mon yers o). Ths sprove the then-

prevn hypothess tht antrctc h

been extensvey cte ony snce the

bennn o the Quternry Er (2.588 mon

yers o).

in 1987, ocen rn on contnent

sheves prove the rst rect evence o

contnent-sce ce sheets cvn t the

paSt CliM ate Change :

the paleo Cene -eoCe ne

therMal MaxiMUM

Extreme changes recorded in the carbon chemistryof oceanic fossil shells indicate that about 55.8 mil-

lion years ago Earth experienced a sudden release

of carbon dioxide into the atmosphere, causing

temperatures to rise by about 4 to 8 C globally in

less than 10,000 years. Because of the timing, which

occurred between the Paleocene and Eocene epochs,

this event is referred to as the Paleocene-Eocene

Thermal Maximum (PETM).

The disruption to the carbon cycle produced

widespreadoceanacidicationandalteredthedeep

oceanecosystem.Bystudyingscienticoceandrilling

cores, scientists found that many species of benthic

foraminifera (single-celled organisms that live in the

deep sea) became extinct during this time. Piston cores

recoveredin2003fromtheSouthAtlanticrstdocu-

mented the size of the PETM carbon release3,000

gigatonsand the subsequent, several hundred

thousand year recovery of ocean chemistry that fol-

lowed the disruption. The PETM is the best analog

of rapid changes in atmospheric carbon dioxide found

to date in the geologic record.

56.055.555.054.554.0

Age (millions of years ago)

3.0a

b

c

2.0

1.0

0

1.0

2.0

13C()

18O()

1.0

1.0

0.5

0

0.5

14

12

10

8Temperature(C)

0

20

40

60

80

100

CaC

O3(%)

1262 (4.8 km)

1263 (2.6 km)

South Atlantic

(water depth)

690

865

525

527

Southern Ocean

Central Pacific

South Atlantic

A rapid increase in carbon isotope ratios in ossilized shells o seafoor organisms collected at

Antarctic, south Atlantic, and Pacic Ocean drill sites indicates a large increase in atmospheric

methane and carbon dioxide during the PETM (top panel). This occurs at the same time as 5 Co global warming (middle panel, presented with oxygen isotope values). Ocean acidication that

ollowed the PETM is indicated by a rapid decrease in the abundance o calcium carbonate (lower

panel). Credit: Zachos et al., 2008.


17/28

15

Changes in global sea level, atmospheric carbon

dioxide concentration, and temperature over the past

55 million years ago, reconstructed rom scientic

ocean drilling data. (A) The global sea level curve

represents changes in sea level in response to

fuctuations in polar ice volume. (B) Dramatic

variability in atmospheric CO2

concentrations (shown

in green) are recorded in shells and other organic

biomarkers preserved in ocean sediments. (C) Changes

in global temperature are shown with oxygen

isotopes derived rom seafoor organisms, representing

global ice volume and deep ocean temperatures.

Credit: Modied rom R. Levy, GNS Science.

A Pleistocene ossil

brittle star ound in a

core sample. Credit:

IODP-USIO.

antrctc costnebrekn o n chunks

s they meet the ocen. urthermore, ce-

rte ebrssements tht becmetrppe n ce n eposte on the ocen

foor when the ce metecoecte n the

Southern Ocen ncte tht the antrctc

ce sheet rew qucky (wthn ew tens o

thousns o yers) n cuse rop n

ob se eve o t est 60 meters.


18/28

16

oxygen iSotopeS

Naturally occurring oxygen (O) exists in nature in the form

ofthreedierentisotopes(16O, 17O, and 18O)atoms with

the same number of protons and electrons but with

dierentnumbersofneutrons.Changesintheratio

between 16O and 18O are related to temperature varia-

tions, changes in evaporation and precipitation, and

the amount of Earths water that is locked in ice

sheets. In the shells of microscopic marine organ-

isms, this ratio acts as a chemical signature that

reveals information about the temperatures

that existed when the organisms were alive.Paleoceanographers use these records to

create a temperature timeline that

extends back millions of years,

providing information about the

extent of glaciations and

Earths ancient climates.

in 1981, scentc ocen rn contrbute to

mjor ncrese n unerstnn these vr-

tons, when n most contnuous sementrecor ws recovere rom the hh-ttue

atntc Ocen. at ths ste, scentsts showe

tht chnes n oxyen sotope rtos (see

box t et.) were correte wth ncreses n

ce-rte ebrs, provn entve evence

tht contnent ce sheets h exste nerby.

Ocen rn estbshe the rst e or the

onset o mjor contnent ctons, bse

on observtons tht ony sm mounts o

ce-rte ebrs were oun n cores beore

ths tme.

Understanding Global Sea LevelChange

Ocen rn on the estern North

amercn contnent mrn hs prove

100 mon-yer recor o ob se eve

chne, own scentsts to enty bure

eroson surces tht correte wth tmeswhen se eve e n nterrupte sement

in contrst to the ery successes n the

antrctc, unerstnn the arctcs c

hstory took r oner. in the m-2000s,

strtey tht combne r shps wth ce-brekers cpbe o rechn remote, ce-cov-

ere res succeee n cpturn 55 mon

yer hstory o cmte chne n the centr

arctc Ocen.

Glacial and Interglacial Cycles

The tme pero between 3 n 2.5 mon yers

o sw ob coon n the expnson o

contnent ce n the Northern Hemsphere.

Ths coon tren ntte seres o c

n nterc cyces controe by on-term

vrtons n Erths orbt.


19/28

17

eposton. Reserchers were be to nk

these nstnces o se eve wth rowth o

the por ce sheets. More thn 30 osctons

n ob se eve urn the Oocene n

Mocene Ers (33 to 6 mon yers o) were

ente.

Recent expetons hve so successuy

re cor rees n crbonte rocks n Tht

n the gret Brrer Ree n austr. TheTht expeton recovere exceent recors

o the st nterc pero (bout 125,000

yers o), when ob se eve ws re-

tvey hh, n o the rp se eve rse snce

the st ce e. These t prove crtc

constrnts on pst se eve hh stns n

hepe qunty the rte o se eve rse.

Orbital Forcing

The stuy o cmte vrbty ue to

chnes n Erths orbt proves one o the

best exmpes o n emern e row-

n exposvey becuse o scentc ocen

rn. in 1979, new corn technooy pro-

uce the rst on, unsturbe recors o

mrne sement, own scentsts to exten

the tme seres o mrne oxyen sotopes

bck 3.5 mon yers. Expetons n the ery

1980s expne the knowee o c-

nterc cyces, the tmn o Northern

Hemsphere ctons, n the chnn n-

ture o the cmte system n response to or-

bt orcn (see box on Mnkovtch cyces,

p.18). Bse on these ery successes, 16-

yer, ob-sce eort to observe n stuy

orbty-orce cmte throuhout tropc n

hh-ttue octons o ocen bsns ws

ntte. These es represente mjor e-

ort, n ts successes re mon the most

sncnt or the ocen rn communty.

The sements coecte throuh scentc

Coral ree and carbonate rocks drilled rom Australias Great Barrier Ree provide insight into the rapid

sea level rise o the last ice age. Credit: European Consortium or Ocean Research Drilling (ECORD)/IODP.

A sediment core rom the eastern Mediterranean Sea demonstrates cyclicity

related to orbital orcing. The alternating layers o dark-colored sediments,

which are rich in organic matter, and light-colored carbonate ooze are due

to changes in the North Arican monsoon pattern. Credit: IODP-USIO.


20/28

18

Abrupt Climate Change

in the m-1980s, scentsts observe tht cecores rom greenn recore seres o

rp n brupt chnes n r temperture

over menn (thousn-yer) tme sces.

Hypotheszn tht nterctons between the

ocen n tmosphere were responsbe or

ths phenomenon, reserchers ocuse on

rp chnes o the North atntc Ocens

re-sce crcuton, whch s rven by -

erences n temperture n snty between

the ocens surce n ts epths. Scentc

ocen rn pye mjor roe n rpy

vncn the knowee o these shorter-

sce temperture swns, rst throuh theuse o exstn cores rom pst rn es n

ter throuh trete smpn opportuntes

cross the obe. These t hve so been

use s nepenent conrmton o the re-

bty o cmte moes.

Co-Evolution o Lie and

the Planet

The presence o e on Erth moes pne-

try processes, ectn the composton n

propertes o the tmosphere, hyrosphere,n the so Erth. The ocen s n ctve

contrbutor to Erth system processes n

so serves s repostory o sements tht

recor chnes n ocenc e. Ocen rn s

the best wy to ccess ths recor n prstne

MilankovitCh

CyCleS

CyclesintheEarthsorbitinuencethe

amountofsunlightthatreachesdierent

partsoftheEarthatdierenttimesofyear.In

the early 20th century, Serbian geophysicist and

civilengineerMilutinMilankoviproposedatheory to explain how these orbital changes could

explain the history of Earths ice ages. His work

explored how the Earths orbital cyclesincluding

the direction (23,000 year period) and tilt (42,000

year period) of the Earths axis, and the shape of its

orbit(100,000yearperiod)hadlong-termeectson

climate, including the timing of glacial and intergla-

cial cycles. Collectively, these cycles are known as

Milankovitchcyclesandtheireectsareknownas

orbital forcing.

ocen rn hve rety vnce the un-

erstnn o orbt cmte vrbty n

ts cuses, n hve prove scentsts wth rmework n tme sce to nterpret the

resuts o stues rom we rne o sc-

pnes, rom the eoscences to rcheooy,

nthropooy, n stronomy. By coectn

n nyzn on, hh resouton recors, re-

serchers hve been be to construct bue-

prnt o mny processes tht ecte Erths

cmte n the stnt pst. Reconton o the

wespre mpct o orbt orcn on cmte

chne hs been mjor outcome o scentc

ocen rn.


21/28

19

orm n wth hh eve o et, n hs en-

hnce stues o e processes on the pnet.

Mny scentc ocen rn projects hve

nvove bostrtrphy, whch s the pro-

cess o corretn n ssnn retve

es o rock or sement usn the osss

contne wthn them. in ton, ocenc

osss cn be use to etermne reon

n ob ecooc or chemc chn-

es. Usn ths recor, scentsts cn n

nsht nto the resons behn chnn

ptterns o e on Erths surce, n hve

been be to eveop new concepts o the

retonshps between evouton, extncton,

n chnes n cmte.

Documenting Asteroid andMeteorite Impacts

in 1980, tem o reserchers oun hh

concentrtons o rum n sement yer

t the 65.5 mon yer o bounry between

the Cretceous n Peoene peros (K-P,

ormery K-T bounry), the sme pero

s mss extncton o nery 75 percent

o the wors speces. irum s n

extremey rre chemc eement n the

Erths crust, but s oun n steros n

Scientic ocean drilling has helped reconstruct past climatic conditions that are relevant or the study o human evolution. (A) shows the timing o hominin evolution, including the rst appearances

o stone tools. In (B) and (C), this is correlated with sediment cores that mark wet and dry cycles related to the North Arican monsoon (a more detailed view can be seen on page 17) and sedimentary

evidence o deep lake conditions in East Arica. (D) and (E) use carbon isotopic analyses o plant biomarkers rom scientic ocean drilling and o soil carbonate nodules to indicate the expansion o

savannah grassland ater 3 million years ago. This is supported by (F), an increase in the relative abundance o Arican mammals that are adapted to graze in the grassland. Credit: DeMenocal, 2011.


22/28

20

comets, en to the hy-

pothess tht n stero h

struck Erth n cuse mss extncton.

Scentsts stue exstn ocen

rn cores to ocument the

ob strbuton o the rum

nomy n ejecte prtces

rom the stero mpct, the

eects on mrne ecosystems,

n the octon o the ster-

o mpct. Smpn o cores

urn ter ocen rn es

prove urther evence or

the rum nomy n mssextncton o mrne ornsms

t the K-T bounry, emon-

strtn the ob strbuton o

these phenomen.

A sediment core across the boundary

between the Cretaceous and Paleogene

periods, known as the K-T boundary. An

asteroid impact is recorded in the dark layer

in the middle o the core record, which is

composed o ejected material. A thin

layer o orange-colored extraterrestrial

material lies above the ejecta. The lighter

layers o sediment above and below the

ejecta contain ossils o ocean micro-

organisms and demonstrate signicant

shits in the type o communities beore

and ater the impact. Credit: IODP-USIO.

Hominin Evolution

Mrne sements ho contnuous n e-

te recors o Cenozoc cmte chne n

speces strbuton. Recovery o these recors

throuh scentc ocen rn hs prove

envronment context or expntons o bo-

oc chnes on the contnentsespecy

the evouton o ery humns n arc. or

exmpe, mrne sement cores re n the

inn n Southern atntc Ocens contn

ust tht swept cross the arcn contnent,

provn evence o fuctutons n arcs

pst cmte. Usn ocen rn recors n

concert wth ke n contnent r cores,

scentsts hve oun tht mjor steps n the

evouton o arcn homnns n other verte-

brtes occurre wth shts to more r, open

contons t specc tmes urn the pst 2.8

mon yers. Ths correton hs strenthene

the nks between humn orns n ther en-

vronment context.


23/28

21

aS THE CURRENT ocen rn prorm

rws to cose n 2013, scentsts, eer

ences, n nternton prtners re -

rey pnnn or the next prorm. Prt o the

pnnn ncue re nternton meet-

n o scentsts, whose thouhts n su-

estons were the bss or rtn scencepn or the propose 2013-2023 scentc

ocen rn prorm. The resut, the Nton

Scence ountons Illuminating Earths Past,

Present, and Future: The International Ocean

Discovery Program Science Plan or 2013-

2023, ws compete n June 2011.

One o the mjor premses o the scence pn

s tht scentc ocen rn hs the poten-

t to contnue enbn essent vnces

n mutpe scentc es, s t hs one n

pst prorms. The scence pn ocuses on

the vue o Erth scence knowee to meetsocet chenes n support better ec-

son mkn.

The scence pn s ve nto our reserch

themes: (1) Cmte n Ocen Chne, (2)

Bosphere ronters, (3) Erth Connectons,

n (4) Erth n Moton. Wthn these themes,

there re 14 specc chenes, or specc

reserch questons. The Nton Reserch

Counc commttee ws ske to ssess the

potent or trnsormtve scentc scovery

rete to the themes n chenes wthn

the scence pn.

assessment of the2013-2023 sCienCe Plan

Illuminating Earths Past, Present, and Future: The International Ocean

Discovery Program Science Plan for 2013-2023, the National Science

Foundations plan or the proposed next phase o scientic ocean drilling,

was published in June 2011. Credit: NSF.


24/28

22

Themes and Challenges rom IlluminatingEarths Past, Present, and Future

The internton Ocen dscovery Prorm

Scence Pn or 2013-2023

Theme 1 - Cmte n Ocen Chne: Ren the Pst, inormn the uture

1. How does Erths Cmte System Respon to Eevte leves o atmospherc CO2?

2. How do ice Sheets n Se leve Respon to Wrmn Cmte?

3. Wht Contros Reon Ptterns o Precptton, such s those assocte wth

Monsoons or E No?

4. How Resent s the Ocen to Chemc Perturbton?

Theme 2 - Bosphere ronters: deep le, Boversty, n Envronment

orcn o Ecosystems

5. Wht re the Orn, Composton, n gob Sncnce o SubsefoorCommuntes?

6. Wht re the lmts o le n the Subsefoor?

7. How Senstve re Ecosystems n Boversty to Envronment Chne?

Theme 3 - Erth Connectons: deep Processes n Ther impct

on Erths Surce Envronment

8. Wht re the Composton, Structure, n dynmcs o Erths Upper Mnte?

9. How re Sefoor Spren n Mnte Metn lnke to Ocen Crust

archtecture?

10. Wht re the Mechnsms, Mntue, n Hstory o Chemc Exchnes Between

the Ocenc Crust n Sewter?

11. How do Subucton Zones intte, Cyce Votes, n generte Contnent Crust?

Theme 4 - Erth n Moton: Processes n Hzrs on Humn Tme Sces

12. Wht Mechnsms Contro the Occurrence o destructve Erthqukes, lnses,

n Tsunm?

13. Wht Propertes n Processes govern the ow n Store o Crbon n

the Sefoor?

14. How o us lnk Subsefoor Tectonc, Therm, n Boeochemc Processes?


25/28

Recommendation: The scientifc ocean drill-

ing community should establish a mechanism to

prioritize the challenges outlined in the scienceplan in a manner that complements the existing

peer-review process.

The commttees nyss o the pst sc-

entc ocen rn prorms oun hs-

tory o mkn exceent use o ecy sm-

pes n t, whch hve hepe to qucky

vnce new res o reserch. The scence

pn s justby ocuse on the mportnce

o uture rn chenes n oes not

expcty ocus on the use o ecy norm-

ton n smpes.

Over, the commttee oun tht the scence

pn presents stron cse or the contnu-

ton o scentc ocen rn, cery en-n ts possbe benets to scence n soc-

ety. in prtcur, stues o the subsefoor

bosphere present opportuntes to enty

mcrobes tht cou be useu to humns,

n contnun stues o pst cmte cou

prove nsht nto the ob n reon c-

mte chne precte or the uture. in -

ton, smpn eeper nto the ocen crust

cou e to better unerstnn o eep

Erth processes, especy technooc

vnces ow more ntct cores to be recov-

ere n expn n stu montorn o ctve

tectonc processes.

Ech o the our themes wthn the scence

pn entes compen chenes wth

potent or trnsormtve scence tht cn

ony be resse by scentc ocen rn.

Some chenes wthn these themes pper

to hve reter potent or trnsormtve sc-

ence thn others.

The commttee etermne tht the

themes n chenes ente n the

scence pn re pertnent n we-jus-

te, thouh there s tte unces to whch o the 14 chenes re

most mportnt. in tmes o thter

scence buets, the scentc

ocen rn communty my wsh

to urther prortze possbe uture

rn objectves.

Cores, packed in tubes, are stored in the

core repository. Credit: IODP-USIO.

23


26/28

24

Technooy hs hepe py vt roe n

chevn mny scentc vnces n prev-

ous scentc ocen rn prorms. Thecommttee oun tht trnsormtve scence

s crtcy epenent on technooc brek-

throuhs, concun tht ny uture scent-

c ocen rn prorm shou contnue to

push the technooc enveope.

Recommendation: Pathways or innovations in

technology should be encouraged. In addition,

setting aside a small portion o scientifc ocean

drilling resources specifcally to promote techno-

logical research and development could greatly

increase the potential or groundbreaking science.

Usn ecy t n smpes to ther mx-

mum cpbtes w contnue to ncrese

the scentc vue o the scentc ocenrn prorms. Expne use o ecy m-

ters cou hep, or exmpe, wth prortz-

ton o rn objectves n the next phse o

ocen rn.

athouh sever ntur ponts o synery

between chenes n themes re we e-

scrbe, the commttee et tht the scence

pn wou hve been strenthene by more

ete exmnton o res o overp

between n mon the scence chen-

es, whch cou hep use resources more

eectvey. or exmpe, ntertn mu-tpe rn objectves n the ery pnnn

stes o expetons wou mxmze

scentc output n reton to costs. There my

be opportuntes or scentc ocen rn

to urther evove exstn pproches to

ntertn mutpe objectves nto sne

expeton.

Recommendation: From the earliest stages o

proposal development and evaluation, pos-

sibilities or increasing program efciency

through integration o multiple objec-

tives into single expeditions should

be considered by proponents and

panels.

Close-up o a drill bit used in scientic

ocean drilling. Credit: Johan Lissenberg,

Cardi University & IODP-USIO.


27/28

This booklet was prepared by the National Research Council based on the report Scientific Ocean

Drilling: Accomplishments and Challenges from the Ocean Studies Board. The project was spon-

sored by the National Science Foundation.

More information about the report is available at www.dels.nas.edu or by

contacting the Ocean Studies Board at (202) 334 2714. To download a free

PDF of the report or purchase a hard copy, please visit the National Acad-

emies Press website at www.nap.edu or contact the National Academies

Press at (800) 624 6242.

FIGURE AND CHART SOURCES:

Page 3, modified from Fisher, A.T., C.G. Wheat, K. Becker, J. Cowen, B. Orcutt, S. Hulme, K.

Inderbitzen, A. Turner, T. Pettigrew, E.E. Davis, H. Jannasch, K. Grigar, R. Adudell, R. Meldrum,

R. Macdonald, and K. Edwards. 2011. Design, deployment, and status of borehole observa-

tory systems used for singlehole and cross-hole experiments, IODP Expedition 327, eastern

flank of the Juan de Fuca Ridge. In Proceedings of the Integrated Ocean Drilling Program 327,

Fisher, A.T., T. Tsuji, and K. Petronotis (Eds.). Integrated Ocean Drilling Program ManagementInternational, Tokyo, Japan.

Page 7, modified from Coffin, M.F., R.A. Duncan, O. Eldholm, J.G. Fitton, F.A. Frey, H.C. Larsen,

J.J. Mahoney, A.D. Saunders, R. Schlich, and P.J. Wallace. 2006. Large igneous provinces and

scientific ocean drilling: Status quo and a look ahead. Oceanography 19(4):150-160.

Page 14, Zachos, J.C., G.R. Dickens, and R.E. Zeebe. 2008. An early Cenozoic perspective on

greenhouse warming and carbon-cycle dynamics. Nature 451:279-283.

Page 19, DeMenocal, P.B. 2011. Climate and human evolution. Science 331(6017): 540-542.

ABOUT THE NATIONAL ACADEMIES

The National Academiesthe National Academy of Sciences, National Academy of

Engineering, Institute of Medicine, and the National Research Councilprovide a public service

by working outside the framework of government to provide independent advice on matters of

science, technology, and medicine. The National Academies enlist committees of the nations top

scientists, engineers, and other experts, who volunteer their time to study specific concerns. The

results of these deliberations are authoritative, peer-reviewed reports that have inspired some of

the nations most significant efforts to improve health, education, and the welfare of the population.


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