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Combining Small-Ve eb a e,
Ma ine and S able-Iso ope Da a o
Recons uc Pas En i onmen s
Juan Ro es1, Na oa Ga cia-Ibaiba iaga2,3, Mikel Agui e4, Blanca Ma ínez-Ga cía2,
Luis O ega5, Ma ía C uz Zuluaga5, Sal ado Bailon6, Ainhoa Alonso-Olazabal5,
Jone Cas años2 & Xabie Mu elaga2
Th ee e y di e en eco ds a e combined he e o econs uc he e olu ion o en i onmen s in
he Can ab ian Region du ing he Uppe Pleis ocene, co e ing ~35.000 yea s. Two o hese eco ds
come om An oliñako Koba (Bizkaia, Spain), an excep ional p ehis o ic deposi comp ising 9
ch ono-cul u al uni s (Au ignacian o Epipaleoli hic). The palaeoecological signal o small- e eb a e
communi ies and ed dee s able-iso ope da a (δ13C and δ15N) om his mainland si e a e con as ed
o ma ine mic o aunal e idence (plank onic and ben hic o amini e s, os acods and δ18O da a)
ga he ed a he sou he n Bay o Biscay. Many adioca bon da es o he An oliña’s sequence, made
i possible o compa e he di e en p oxies among hem and wi h o he well-known No h-A lan ic
eco ds. Cooling and wa ming e en s egionally eco ded, mos ly coincide wi h he clima ic e olu ion
o he Uppe Pleis ocene in he no h hemisphe e.
The econs uc ion o pas en i onmen s has been add essed om many disciplines and pe spec i es in
he pas , being undamen ally conce ned wi h wo hings: a well-de ined and easonably comple e en i-
onmen al eco d and an adequa e ch onological amewo k. A holis ic e o in his sense, is o be ound
a he ecen ly published esul s o he INTIMATE p ojec 1. An ex ensi e compila ion o clima ic and
palaeoen i onmen al econs uc ions o he 60—8 ka pe iod in he No h A lan ic Region is p esen ed
he ein, wi h au ho s using di e se eco ds, as he G eenland ice-co es, ee- ings, pollen, eph och onol-
ogy, speleo hems, and ma ine p oxies, among o he s. Independen ly, o he i s ime, we combine he e
adiome ic da ing wi h h ee e y di e en p oxies, i.e., small e eb a es, s able iso opes o he bi o es,
and ma ine eco d (os acods and o amini e s), commonly used each one o hem sepa a ely2–4, o
econs uc he e olu ion o landscapes and en i onmen s in he Can ab ian Region (Fig.1) du ing he
Uppe Pleis ocene, co e ing a ime span o ~35.000 yea s.
The i s p oxy is based on small e eb a es (Fig.2). Diges ion sub-p oduc s o bi ds o p ey (i.e.,
ejec ion pelle s) and small ca ni o es a e he main sou ces o small- e eb a e deposi ion in a chae-
ological si es5, being ca es and ock shel e s pa icula ly p opi ious places o hose animals o nes
a he en ances, o o build bu ows inside, espec i ely3,6,7. Unlike la ge mammal emains (many o
hem p oduc o human selec ion), small- e eb a e accumula ions easonably well e lec local bioceno-
sis, despi e una oidable il e s due o speci ic p eda o s5. Mo eo e , small e eb a es a e pa icula ly
1A chéozoologie, A chéobo anique : Socié és, p a iques e en i onnemen s (UMR 7209), So bonne Uni e si és,
Muséum na ional d’His oi e na u elle, CNRS, CP56, 55 ue Bu on, 75005 Pa is, F ance. 2UPV-EHU, Facul ad de
Ciencia y Tecnología, Depa amen o de Es a ig a ía y Paleon ología, Apa ado 644, E-48080 Bilbao, Spain. 3UPV-
EHU, Facul ad de Le as, Depa amen o de Geog a ía, P ehis o ia y A queología, c/Tomás y Valien e s/n, 01006
Vi o ia-Gas eiz, Spain. 4UNED, CA Be ga a, San Ma in Agi e Plaza 4, E-20570 Be ga a, Spain. 5UPV-EHU, Facul ad
de Ciencia y Tecnología, Depa amen o de Mine alogía y Pe ología, Apa ado 644, E-48080 Bilbao, Spain. 6UMR
7209-UMR 7194, CNRS Dépa amen Ecologie e Ges ion de la Biodi e si é (EGB), So bonne Uni e si és, Muséum
na ional d’His oi e na u elle, CNRS, CP55, 55 ue Bu on, 75005 Pa is, F ance. Co espondence and eques s o
ma e ials should be add essed o J.R. (email: [email p o ec ed])
Recei ed: 22 Ap il 2015
Accep ed: 13 Augus 2015
Published: 22 Sep embe 2015
OPEN
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sensi i e o clima ic and habi a changes, and hei shi s along ime in e ms o axa and numbe o
specimens can be success ully used o he econs uc ion o pas en i onmen s3,6–11.
Ano he p oxy is gi en by he analysis o he s able-iso ope da a om bone collagen o he bi o es.
Va iabili y in clima e and local en i onmen de e mines ood sou ce a ailabili y, and di e en ood sou ces
ha e pa icula s able ca bon and ni ogen iso ope alues. Since he ood iso opic signal is e lec ed
in bone collagen, his can be used as a p oxy o in e palaeodie a y and palaeoclima ic a ia ions12,13.
The s able ca bon iso ope a io (δ
13C) o he bi o e issue is ela ed o ac o s such as he en i onmen ,
he pho osyn he ic pa hways o consumed plan ma e , humidi y, wa e a ailabili y, salini y, and pa ial
a mosphe ic pCO214,15. Fo ins ance, plan s in woody landscapes appea o lead o δ
13C deple ion com-
pa ed o plan s o open habi a s ( he so-called ‘canopy e ec ’16,17). By con as , ni ogen iso ope a ios
(δ
15N) p ese ed in animal issues a e ela ed o ac o s such as die , clima e, and wa e a ailabili y18–21.
In addi ion, he δ
15N o he bi o es’ bone collagen may e lec p ocesses o soil o ma ion, especially in
en i onmen s wi h in luence o pe ma os 19,20,22. Du ing cold pe iods, he δ
15N in he collagen o he bi-
o es shows lowe alues, and he ea e , om a diach onic s andpoin , an inc ease o δ
15N alues o e
ime may be due o empe a u e ising pa allel o highe o ganic ac i i y in soils19,20,22,23. As plan δ
13C
and δ
15N signals e lec en i onmen al pa ame e s, and iso ope a ia ions occu du ing pe iods o g ea
clima ic change, a ia ions in collagen iso ope alues e lec he e ec s ha he en i onmen may ha e
had on auna19–24.
The ma ine eco d, ep esen ed he e by plank onic and ben hic o amini e s and os acods ga he ed
a he sou he n Bay o Biscay (Fig.3), no so a om An oliñako Koba si e (see Fig.1 and Me hods),
has been ex ensi ely used o palaeoen i onmen al econs uc ions in he Qua e na y pe iod4,25–28. The
plank onic o amini e Neogloquad ina pachyde ma sinis al (sin), in pa icula , is a pola species ha
appea s in pe cen ages o > 90% o he no h o he No h A lan ic Pola F on 29, being i s abundance
a use ul p oxy o iden i y he me idional mig a ion o he Pola F on du ing he Qua e na y. In he
wes e n Ibe ian Ma gin, high quan i ies o his axon a e connec ed o colde episodes o he las glacial
pe iod30. Hence, peaks o his species can be easonably co ela ed wi h cold clima e e en s (i.e., Hein ich
E en s and G eenland S adials). The e m “No he n gues s” is e e ed only o os acod axa cu en ly
li ing ou side he Medi e anean Sea (a no he n la i udes), and which a i e o he Medi e anean du -
ing “cold” Qua e na y clima ic episodes31. Following his c i e ia, he e we conside as “No he n gues s”
such os acod species ha do no li e oday in he Bay o Biscay (ha ing a ci cumpola dis ibu ion,
i.e., “cold-wa e ” p oxies), and which en e in o he Basque shel only du ing some cold clima ic e en s,
namely Acan hocy he eis dunelmensis, Cy he op e on es udo and “T achylebe is” sp.
The s able oxygen iso ope a io (δ
18O) is one o he mos ex ensi ely used ools in palaeoclima ology
and palaeoceanog aphy. In ma ine sedimen s, he δ
18O alues o plank onic and ben hic o amini e
Figu e 1. Geog aphical loca ion. (a) An oliñako Koba si e (Gau egiz-A eaga, Bizkaia, Spain). (b) Ma ine
co es aken a he ou e Basque shel (Sou he n Bay o Biscay). The igu e was designed h ough he
combined use o Mac omedia F eehand MX, Adobe Illus a o CS6 and Adobe Pho oshop Elemen s 12.
Figu es1a and 1b we e modi ied unde pe mission om elsewhe e3,28.
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shells a e used as p oxies o econs uc a ia ions in salini y, empe a u e and iso opic composi ion o
shallow (plank onic) and deep (ben hic) sea wa e , o analyze luc ua ions in global ice olume, o iden i y
changes in oceanic wa e masses, and o cons uc a high esolu ion ime scale du ing he Qua e na y32,33.
Figu e 2. Selec ed specimens o small e eb a es om An oliñako Koba (Gau egiz-A eaga, Bizkaia,
Spain). Ma mo a ma mo a (1) igh D4 in occlusal iew; Apodemus syl a icus (2) igh M2 in occlusal
iew; A. la icollis (3) le M2 in occlusal iew; Eliomys que cinus (4) igh M1 o M2 in occlusal iew;
A icola amphibius (5) igh m1 in occlusal iew; Pliomys lenki (6) igh m1 in occlusal iew; Mic o us
(Alexand omys) oeconomus (7) le m1 in occlusal iew; Chionomys ni alis (8) igh m1 in occlusal iew;
Mic o us (Te icola) lusi anicus (9) igh m1 in occlusal iew; M. (Mic o us) ag es is (10) igh m1 in occlusal
iew; M. (M.) a alis (11) le m1 in occlusal iew; Neomyni inde . (12) le mandibula condyle in pos e io
iew; Neomys sp. (13) igh i1 in la e al iew; So ex c . co ona us (14) incomple e le mandible wi h i1
(b oken), a1 and p4; (15) le M1 in occlusal iew; S. minu us (16) incomple e le mandible in medial iew;
C ocidu a ussula (17) igh m1 in la e al iew; Talpa sp. (18) le hume us in an e io iew; Anguis agilis
(19) incomple e igh maxillae in medial iew; Co onella gi ondica (20) unk e eb ae in en al iew;
Vipe a sp. (21) unk e eb ae in en al iew; Rana g . empo a ia-ibe ica (22) sac al e eb ae in en al
iew. Scale ba = 1 mm o igu es2–11, 13, 16 and 17; 2 mm o igu es1, 12, 14, 15, and 19–22; 4 mm o
igu e 18.
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The δ
18O a io o many plank onic and ben hic o amini e species, such as Globige ina bulloides and
Cibicides spp., has been conside ed o be in equilib ium wi h he δ
18O signal o su ace and bo om
wa e s, o o ha e a cons an o se , wha allows o iden i y changes in wa e masses p ope ies and es ab-
lish a consis en s a ig aphy o ma ine sedimen a y co es o he No h A lan ic Ocean34,35. The e o e,
he e we use he oxygen iso opic signal δ
18O measu ed in Loba ula loba ula (ben hic o amini e ) and G.
bulloides (plank onic o amini e ) o de ec changes on he cha ac e is ics o , espec i ely, bo om and
su ace wa e masses in he Basque shel du ing he la e Qua e na y.
An oliñako Koba (AK) (Gau egiz-A eaga, Bizkaia, Spain: Fig. 1a) is an excep ional
a chaeo-palaeon ological ka s ic deposi wi h a long Uppe Pleis ocene sequence, comp ising nine
ch ono-cul u al uni s: Au ignacian, e ol ed Au ignacian, G a e ian, Uppe Solu ean, la e Lowe
Magdalenian, Uppe Magdalenian, Azilian, and ancien Epipaleoli hic36–38. The e a e also sca ce
p e-Au ignacian e idences o human p esence in an unde lying s ill unda ed laye 36. The ch onology
o AK oughly goes om nea ly 44 o 9 ka cal BP. De ails o he s a ig aphy, li hic indus ies, po able
a , and con ex ualiza ion o he si e in he egional p ehis o y a e o be ound elsewhe e36–40. The good
p ese a ion o he ma e ials om AK allowed us o ob ain bo h he small- e eb a e collec ion and he
ed dee (Ce us elaphus) bone samples, he la e used o s able iso ope analysis (see Me hods). Pollen
co es we e also aken om he en i e sequence. Un o una ely hey e ealed o be s e ile in all cases
(Ma ía José I ia e, pe s. comm.).
Many adioca bon da es ob ained o he AK’s sequence (see Table1 and Fig.4, 1s and 2nd columns),
made i possible o co ela e he land and ma ine eco ds be ween hem, and hen wi h sedimen ological
and palynological episodes o he Can ab ian Region41,42, wi h he a ia ions o he eus a ic sea le el43,44,
and wi h a δ
18O cu e om a deep ice-co e o no h G eenland (NGRIP45). Two main objec i es a e pu -
sued in his s udy: 1) con as he mainland and ma ine eco ds o he same egion, illing he gaps ha
commonly exis along he mainland sequences wi h he usually mo e comple e ma ine eco d; and 2)
ob ain a con inuous palaeoen i onmen al econs uc ion o he 44–9 ka cal BP pe iod a he Can ab ian
Region by co ela ing and c oss-checking se e al p oxies (small e eb a es, ma ine eco d and s able
iso opes o he bi o es), co ela ing hose p oxies in u n wi h well-known No h-A lan ic eco ds.
Resul s
Small e eb a es. The small- e eb a e assemblage om AK comp ises 28 axa: ou so icids
(So ex c . co ona us, S. minu us, Neomys sp., and C ocidu a ussula); one alpid (Talpa sp.); one sciu id
(Ma mo a ma mo a); wo gli ids (Glis glis and Eliomys que cinus); wo mu ids (Apodemus syl a icus and
A. la icollis); se en c ice ids (A icola amphibius, Chionomys ni alis, Pliomys lenki, Mic o us (Te icola)
lusi anicus, M. (Alexand omys) oeconomus, M. (Mic o us) a alis, and M. (M.) ag es is); i e amphibians
(Aly es obs e icans, Bu o bu o, B. calami a, Rana g . empo a ia-ibe ica, and T i u us sp.); and six ep iles
(Anguis agilis, Chalcides s ia us, Co onella gi ondica, c . Na ix, Vipe a sp., and Lace idae inde .).
Figu e4 econs uc s he AK habi a dis ibu ion based on changes in he small-mammal (7 h column)
and amphibian and ep ile (8 h column) communi ies o e ime, espec i ely. The equencies o he di -
e en axa (exp essed in NISP and MNI) and hei habi a a ini ies a e gi en in supplemen a y Tables 1
1
2
3
4
5
6
Figu e 3. Selec ed specimens o o amini e s and os acods om he ou e Basque shel (Sou he n
Bay o Biscay) used in his s udy. (1) Ben hic o amini e species: Loba ula loba ula, spi al iew. (2-3)
Plank onic o amini e species: (2) Globige ina bulloides, o al iew; (3) Neogloboquad ina pachyde ma le
coiling (sin), o al iew. (4–6) “No he n gues ” os acod species (all la e al ex e nal iews): (4) Cy he op e on
es udo, igh al e; (5) Acan hocy he eis dunelmensis, igh al e; (6) “T achylebe is” sp., le al e. Scale ba
= 100 μ m.
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and 2. The species we e o de ed by s a ig aphic le els co e ing he Au ignacian o ancien Epipaleoli hic
pe iods (Sm-P o Lanc), plus some p e-Au ignacian laye s wi hou a speci ic ch ono-cul u al assigna ion
(Sm o B-Am). The e a e ce ain hia uses and e osi e episodes along he sequence shown in Fig.4.
Fi s o be no iced is he p e-eminence o o es s a he bo om o he sequence. Du ing p e-Au ignacian
imes, woodlands we e impo an in he icini y o he ca e acco ding o bo h he amphibian and ep ile
(AR) eco d (Le el Sm) and he small-mammal (SM) eco d (Le el Lsm-P). Fo he i s clea ly de ined
a chaeological le el (Sm-P), and since sligh ly be o e, he SM eco d documen s wo peaks o o es ,
he highes o he sequence, wi h a mode a e p esence o open landscapes as well. The e is a no o ious
peak o ocky habi a s a he op o Sj/P. The le el called lowe Lmbk/Smk, assigned o he e ol ed
Au ignacian, is cha ac e ized by an equilib ium be ween woodland and meadows acco ding o he SM,
and by a peak o open landscapes acco ding o he AR. The e is no con adic ion bu al e na ion in his
case, as shown in Fig.4.
Some deg ee o con adic ion be ween he SM and AR eco ds is p esen in he G a e ian laye s.
While he SM show a nea ly simila ep esen a ion o o es s and meadows, he AR exhibi wo peaks
o meadow and one o woodland, wi h mo e p esence o wa e componen han in he SM. This dis-
c epancy may be a bias due o he lowe NISP o AR espec o SM in hese pa icula le els (compa e
uppe Lmbk/Smbk + Lab/Sab in supplemen a y Tables 1 and 2). A e he second hia us o he sequence,
du ing Uppe Solu ean imes, and acco ding o he SM, he e a e wo peaks o o es a le els Lmc and
Lmb, espec i ely, and a signi ican inc ease o ocky habi a s (in de imen o woodland and meadows)
in Lmb, immedia ely be o e he second peak o o es . The AR eco d suppo s he wo o es peaks o
he SM, being hem conside ably highe in AR.
The la e Lowe Magdalenian (lowe Lgc) shows a p edominance o woodland o e open landscapes,
especially in he SM. This endency con inues a e a long hia us. Du ing Azilian imes (uppe Lgc) he e
a e peaks o meadows in de imen o wa e habi a s bo h in he SM and AR. The o es componen
emains high, bu mo e acco ding o he SM. Finally, owa ds he Ancien Epipaleoli hic ( ep esen ed by
Le el Lanc), we obse e a educ ion o woodland and open e i o y in a o o wa e s a he SM column,
bu an inc ease o meadows in he AR, in de imen o bo h o es and wa e habi a s. The ocky a eas
a e mode a ely ep esen ed since he Azilian o he op o he sequence, bu only a he AR column.
S able ca bon and ni ogen iso opes. The esul s o he ca bon (C) and ni ogen (N) iso ope anal-
ysis o he C. elaphus bone samples o AK a e displayed in columns 9 h and 10 h o Fig.4, espec i ely.
The a ia ion in ed dee collagen δ
13C alues along he sequence is due o consump ion o di e en ypes
o plan s. Ce us elaphus is classi ied as an in e media e eede , wi h a mixed die be ween g azing and
b owsing46,47. Red dee δ
13C alues could be a ibu ed o g aminoid and sh ubbe y eeding, pa icula
o semi-open g asslands18–20. The δ
13C alues o AK specimens show a dec easing end om he Uppe
Solu ean o he Azilian (~23–12 ka cal BP), anging om δ
13C − 20.3 o − 21.0‰ (supplemen a y Table
3 and supplemen a y Fig. 1a). This a ia ion sugges s a p og essi e inc ease in o es co e 16. F om he
Au ignacian o he G a e ian (~36–30 ka cal BP) an opposi e end is eco ded, p obably e lec ing a
dec ease o woodlands along his pe iod.
Cul u al ho izon Le el
Radioca bon age
Lab code Sample
14C y BP Cal y BP 2σMean p ob.
Epipaleoli hic Lanc 8680 ± 60 9850–9490 9642 G A-23811 Cha coal
Azilian E-Lanc 10220 ± 40 12140–11740 11935 Be a-215544 Bone (AK-3)
Azilian Uppe Lgc 10800 ± 40 12800–12680 12712 Be a-215543 Bone (AK-2)
la e Lowe Magdalenian Lowe Lgc 14580 ± 70 – 14680 ± 100 17870–17710/17930–17730 17760–17863 Be a-230281/G N-23784 Bone (AK-10)/Bone
Uppe Solu ean Lmb 17340 ± 100 21090–20530 20918 Be a-251301 Bone (AK-21)
Uppe Solu ean Lmc 19020 ± 120 23250–22570 22897 Be a-230284 Bone (AK-13)
Uppe Solu ean Lmc 19280 ± 120 23450–22850 23225 G N-23785 Bone
G a e ian Lab/Sab 22640 ± 120 28000–26760 26973 Be a-233766 Bone (AK-14)
G a e ian Uppe Lmbk/Smbk 26710 ± 180 31880–31280 30905 Be a-230282 Bone (AK-11)
G a e ian Uppe Lmbk/Smbk 27520 ± 190 32430–31750 31326 Be a-230279 Bone (AK-7)
E ol. Au ignacian Lowe Lmbk/SmK 29990 ± 230 34670–33870 34065 G A-23898 Cha coal
E ol. Au ignacian Lowe Lmbk/SmK 30640 ± 240 35290–34210 34576 Be a-251304 Bone (AK-31)
Table 1. Lis o adioca bon ages om he An oliñako Koba s a ig aphic column. Including cul u al
ho izons, ch ono-s a ig aphic uni s, labo a o y codes and he elemen s om whe e he samples we e aken.
Da es we e calib a ed a 95% con idence in e als (2σ ) using he In Cal13.14c da a se 66. Mean p obabili y
calcula ed wi h he Calib7.0.467.
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Rega ding he ni ogen, we obse e an inc ease in δ
15N alues om he Uppe Solu ean o he
Azilian, mean alues a ying be ween δ
15N 2.8 and 4.4‰ (supplemen a y Table 3 and supplemen a y
Fig. 1b). This inc ease could be he esul o a p og essi e ise in empe a u e19,20,22,23 (see In oduc ion).
F om he Au ignacian o he G a e ian he end is ambiguous. Du ing he G a e ian (uppe Lmbk/
Smbk + Lab/Sab), δ
15N alues exhibi wo se s o isola ed alues: one wi h high alues (δ
15N = 7–8‰)
and o he wi h lowe alues (δ
15N < 5‰). The p esence o hese wo se s in he ed dee o AK could
ep esen popula ions coming om di e en e i o ies. I we in e p e he highe alues as belonging o
non-local indi iduals, and we assume he lowe alues as alid, hen he esul ing endency o a dec ease
in empe a u es would be in ag eemen wi h he end in e ed om he δ
13C (compa e supplemen a y
Figs. 1a and 1b).
Ma ine eco d. The palaeoceanog aphic e olu ion o he Basque shel du ing he la e Qua e na y,
based on mic o aunal (% o N. pachyde ma sin and “No he n gues ” os acod species) and iso opic (δ
18O
on G. bulloides [bull] and L. loba ula [lob]) signals, is shown in columns 11 h and 12 h o Fig.4, e lec ing
he in luence o di e se wa e masses in his a ea.
Du ing MIS 3, he high pe cen age o N. pachyde ma sin, oge he wi h he posi i e alues o δ
18Obull,
indica es he in luence o cold pola su ace wa e s in he Basque shel . Rega ding he ben hic eco d,
Figu e 4. Mul i-p oxy es ima ed palaeoen i onmen al econs uc ion o he Can ab ian Region du ing
he Uppe Pleis ocene. F om le o igh , columns ep esen he 14C BP adioca bon da es (wi h labo a o y
codes); he 14C BP 2σ calib a ed (cal) adioca bon da es using he In Cal13.14c da a se 66; he s a ig aphic
le els o AK; he cul u al ho izons de ined by hei a chaeological con en s; he s a ig aphic sequence o AK;
he loca ion o he samples; he small-mammal axa g ouped by hei habi a equi emen s; he amphibian
and ep ile axa g ouped by hei habi a equi emen s; he δ
13C and δ
15N alues o C. elaphus om AK; he
ela i e abundances o N. pachyde ma sin (plank onic o amini e ) and “No he n gues ” species (ben hic
os acods) o e ime; he δ
18O signals o G. bulloides (plank onic o amini e ) and L. loba ula (ben hic
o amini e ) o e ime; he sedimen ological41 and palynological42 episodes o he Can ab ian Region; he
No h-A lan ic sea-le el cu es43,44; and a δ
18O cu e ob ained om a deep ice co e o No h G eenland
(NGRIP45) displaying some well-known No h-A lan ic clima ic episodes (HE 1 phases52 and limi s be ween
MIS68 we e aken om elsewhe e). AK, An oliñako Koba; ST., s e ile laye ; P ebo ., P ebo eal; MWP, mel
wa e pulse; HCE, Holocene Cooling E en ; YD, Younge D yas; B/A, Bölling/Alle öd; GI, G eenland
In e s adial; HE, Hein ich E en ; LGM, Las Glacial Maximum; MIS, Ma ine Iso ope S ages.
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he iso opic signal (δ
18Olob) ma ks he p esence o cold bo om wa e s in he Basque shel . Howe e , he
sca ci y o “No he n gues ” os acod species shows he absence o inpu s o subpola bo om wa e s4.
The HE 3 (~31.3 ka cal BP) is a ema kable pe iod: he ma ine eco d e lec s he a i al o bo h su ace
and bo om cold subpola wa e s in o he Basque shel
4,28.
A 23.9 ka cal BP, Hein ich E en (HE) 2 is de ec ed by an inc ease in he pe cen age o N. pachyde ma
sin synch onic o a peak o δ
18Obull, e lec ing he a i al o cold pola su ace wa e s4,28. This e en is
ollowed by a dec ease in he iso opic signal (~23.2 ka cal BP) ha co esponds o he wa m e en GI-2.
The dec ease in abundance o N. pachyde ma sin and δ
18Obull alues du ing he Las Glacial Maximum
(LGM) compa ed o HE 2, sugges s an inc ease in empe a u e, a dec ease in salini y o su ace sea
wa e 48, and/o homogenisa ion o he wa e column49. Howe e , he ben hic signal e lec s an inpu o
cold subpola bo om wa e s in o he Basque shel a ~21.3 ka cal BP4. This cold wa e shi a ec ed only
bo om wa e s, and e ea ed du ing he es o he LGM.
A he end o LGM (~20.1 ka cal BP), a new peak o abundance o N. pachyde ma sin shows he
en ance o cold pola su ace wa e s in o he Basque shel . This can be co ela ed wi h he e ea and
mel ing o he Eu opean ice shee s and glacie s occu ed a 20 ka cal BP50, which caused a sea-le el ise
a a ound 19 ka cal BP (19 ky-mel wa e pulse; 19 ky-MWP in Fig.4). F om ~18.6 o ~15 ka cal BP, he
HE 1 is cha ac e ized by he a ia ions in ela i e abundance o N. pachyde ma sin, “No he n gues s”
and δ
18Obull and δ
18Olob signals, e lec ing he inpu o bo h cold su ace and bo om wa e masses in o
he Basque shel , coming om he ci cumpola a ea o he No h A lan ic Ocean4,28. These end can be
co ela ed wi h he age p e iously p oposed o HE 1 in he Bay o Biscay, i.e., ~18 ka cal BP51–53.
The e osional hia uses obse ed i s a he beginning o MIS 2 (27.7–23.9 ka cal BP) and hen a he
beginning o he second phase o HE 1 (HE 1b)52 (17.1–16.5 ka cal BP), seem o be ela ed o he sea
le el ise s a ing a ~17 ka cal BP54 ha cha ac e ized he las Deglacia ion (14.7–11.5 ka cal BP, begin-
ning o MIS 1)4,28. This sea-le el ise shows i s maximum a es om ~14.6 o ~13.8 ka cal BP, du ing
he mel -wa e -pulse 1a e en (mwp-1a in Fig.4)54. A e he end o he Younge D yas (YD, 11.3 ka cal
BP) i comes a pe iod o highe sea-le el a es, called mwp-1b54 (Fig.4), being he sea-le el app oxi-
ma ely − 60 m espec o he cu en le el. On he con inen al shel o he A mo ican ma gin (F ench
ma gin, no he n pa o Capb e on Canyon), simila e osi e p ocesses we e obse ed du ing he las
Deglacia ion, due o he same phenomenon55. In he Basque shel , his ise, which occu ed du ing he
beginning o MIS 1 (las Deglacia ion and ea ly Holocene), is accompanied by a wa ming endency
on bo h su ace and bo om wa e s, as shown by he ma ine p oxies. The inc ease in abundance o
“No he n gues s”4,28 and δ
18Olob signal a ~9.4 ka cal BP implies he inpu o cold subpola bo om wa e s
ha may co espond o he Holocene Cooling E en (HCE) 656.
Discussion
Many p oxies ha e been p e iously used o econs uc pas en i onmen s (e.g., G eenland ice-co es,
ee- ings, pollen, eph och onology, speleo hems, and ma ine eco d), and some comp ehensi e holis ic
e o s ha e been ecen ly accomplished1, bu none o hem ha e di ec ly compa ed small e eb a es,
ma ine eco d and s able iso opes o ed dee o yield a mo e comple e and accu a e pano ama.
Ou s udy shows how use ul i can be o compa e he land and ma ine eco ds, pa icula ly when
he samples come om geog aphically close loca ions (Fig. 1), wha p e en s incompa ibili ies in he
sequences. The en i onmen al cu es ob ained om o amini e s and os acods o he Sou he n Bay o
Biscay a e con empo aneous and complemen a y o hose cons uc ed wi h he small e eb a es (mam-
mals, amphibians and ep iles) om AK. Some e osi e episodes and/o s e ile laye s along he main-
land sequence, p o oking gaps in he eco d, can be success ully ul illed by he ma ine eco d ( ela i e
abundances and iso opic signals o ce ain axa), as i is he case o he pe iods ~41.2–37.4 ka cal BP,
~33.6–32 ka cal BP, ~18.2–20.5 ka cal BP, and ~17.6–14.4 ka cal BP. In spi e ha he ma ine eco d is usu-
ally mo e comple e han he mainland one4,28, he long e osi e hia us in he ma ine co es o he Basque
shel be ween 27.7 and 23.9 ka cal BP is pa ially co e ed by he small- e eb a e sequence.
The di e en eco ds p esen ed in Fig.4 can be ea ed al oge he o independen ly. I aken sepa a ely,
he small- e eb a e eco d can be con as ed o o he palaeoen i onmen al econs uc ions pe o med
o he same egion, as hose o San imamiñe3 ( e y close o AK), Askondo11, El Mi ón6, El Conde10, and
Valda a a-19. The mainland s able-iso ope e idence can be compa ed wi h he ecen con ibu ions made
o Kipu z IX2 and El Mi ón57; and, inally, he econs uc ions done depa ing om oceanic da a (% o
species and s able iso opes o o amini e s) can be con as ed o some o he s ob ained o he sou he n
Bay o Biscay51,53.
I used al oge he , i is in e es ing o ha e a deepe look in o he pe iods o he sequence whe e
i is possible o con as he esul s o he h ee di e en eco ds (small e eb a es, ma ine and s a-
ble iso opes) o he Can ab ian Region, and o compa e hem in u n wi h some o he well-known
No h-A lan ic eco ds (sedimen ological, pollen, eus a ic sea-le el and NGRIP) o ge a wide and mo e
complex iew. Du ing he e ol ed Au ignacian pe iod (~35–33.6 ka cal BP), o ins ance, small e e-
b a es show a combined (i.e., mammals plus amphibians and ep iles) scena io o a ce ain equilib ium
be ween woodland and meadows, which coincides wi h he in e media e alues o he δ
13C and δ
15N
(supplemen a y Table 3 and supplemen a y Fig. 1), meaning mode a ely o es ed landscapes and mild
empe a u es, espec i ely. The pe cen ages o N. pachyde ma sin and he sligh ly posi i e endency o
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δ
18Obull alues indica e mode a e in luence o pola su ace wa e s in he Basque shel , i s e ec s in he
gene al en i onmen being he ea e also mode a e.
The HE 3 (~31.3–29.8 ka cal BP) in he Basque shel is clea ly shown by he inc ease o N. pachyde ma
sin, “No he n gues s” and he alues o δ
18Obull and δ
18Olob, which indica e he a i al o bo h su ace
and bo om subpola wa e s, and i s consequen in luence in he gene al clima e. This co esponds o a
end o de o es a ion in mainland, as shown by he highe alues o δ
13C espec o he Au ignacian, and
a dec ease in empe a u es i we conside he lowe alues o δ
15N as alid (see Resul s). The combined
pano ama e lec ed by he small e eb a es coincides wi h he δ
13C alues in showing a mo e open sce-
na io, especially no o ious in he amphibian and ep ile eco d. The pa ial coincidence wi h he Kessel
pollen phase should no be conside ed, as he ch onology o his wa m episode (likely mo e ela ed o
GI-5) and o he s has been b ough in o ques ion42. A 23.2 ka cal BP he e was a ema kable dec ease
o he G. bulloides iso opic signal. A he same ime, a woodland peak is de ec ed in he small-mammal
eco d, which oughly coincides wi h he GI-2 wa m e en . The peak o ocky habi a s a 21.3 ka cal BP,
du ing he LGM, could be ela ed o he high alues o δ
13C (de o es a ion) and he low alues o δ
15N
( all in empe a u e). In he oceanic on , high a ios o he plank onic and ben hic iso opic signals
e lec inpu s o cold supe icial and bo om wa e s. The e is a peak o “No he n gues s” a he same
ime. In sedimen ological and palynological e ms, he ocky-habi a peak coincides wi h he ansi ion
be ween he Can ab ian phases I (Oldes D yas) and II (Lascaux)41, being he o me especially cold and
humid.
Du ing he occupa ion o AK by Lowe Magdalenian people, a end o p og essi e o es a ion o
landscapes can be in e ed om bo h he small- e eb a e eco d and he δ
13C alues, he δ
15N a io
showing a pa allel, no su p ising, ise in empe a u e espec o p e ious Solu ean imes. The a i al
o bo h bo om and su ace cold wa e masses o he Basque shel con inues o e his pe iod, bu he e
is a d op in quan i ies o N. pachyde ma sin and nega i e ends o δ
18Obull and δ
18Olob a he uppe mos
pa . These cu es nicely i wi h phase V o he Can ab ian Region41, in he sedimen ological on .
The Azilian ch ono-cul u al pe iod oughly coincides wi h he YD. This is a ime o peaks o woodland
in he small- e eb a e eco d, which co espond o o es a ion a e he δ
13C signal, and o ascending
empe a u es a e δ
15N alues. Numbe s o N. pachyde ma sin and δ
18Obull alues diminish acco dingly.
The ben hic signal, howe e , shows inpu s o subpola bo om wa e s owa ds he hal o his pe iod. The
palynological (D yas III) and sedimen ological (Phase IX) da a e lec s mild condi ions41. This end o
p og essi e inc ease in woodland and ise in empe a u es om Magdalenian imes up o he Holocene
is clea ly eco ded also in he sequences o San imamiñe3, El Mi ón6, and Kipu z IX2.
Along HE 3 and HE 2, con a y o he es o he p oxies, he small mammals do no display pa -
icula ly open landscapes. A he op o he Uppe Solu ean, he e a e peaks o o es acco ding o he
small- e eb a e e idence (especially amphibians and ep iles) du ing he LGM, while he s able iso opes
o ed dee and he ma ine signals sugges p io i y o meadows and low empe a u es. Finally, owa ds
Epipaleoli hic imes, he e is a e ea o woodlands a e he small e eb a es, wha is no cohe en wi h
wha is in e ed om he ma ine eco d. I should be s a ed hen ha oge he wi h coincidences, ou
sequence displays also some disc epancies: ei he some p oxies do no e lec speci ic e en s wi h he
same in ensi y as o he s, o hey show opposi e ends in ew cases. These inconsis encies ep esen a
challenge o u u e s udies.
Me hods
Small- e eb a e ma e ials. The assemblage includes nea ly 31400 elemen s, o which 2470 we e
iden i ied ei he o he amily, genus and/o species le el. To ob ain he samples, he sedimen om he
di e en s a ig aphic le els o he ca e was wa e -sc eened using a s ack o sie es o dec easing mesh
size (4 and 0.5 mm). The small e eb a es we e collec ed om esidue coa se han 0.5 mm. Fossils
we e so ed, classi ied, coun ed, and s udied wi h he aid o a binocula mic oscope (Nikon SMZ-U; 7x,
20x, and 40x magni ica ions). Mos o he elemen s a e ee h, isola ed mandibles, skull agmen s, and
pos c anial bones.
Sys ema ic a ibu ion and quan i ica ion. Each small- e eb a e axon was iden i ied based on
c anial and pos -c anial diagnos ic elemen s: isola ed ee h o he Mu inae and Gli idae; i s lowe
mola s o he A icolinae; mandibles, maxillae, isola ed ee h, and pos -c anial skele on o he Talpidae
and So icidae; hume us, ilium, scapula, and sac um o amphibians; skull elemen s, e eb ae and os e-
ode ms o liza ds, and unk e eb ae o snakes. The axonomic classi ica ion ollows well-known
e e ences58,59. In spi e ha in Fig.2 we show wo disce nible second uppe mola s o Apodemus syl a icus
and A. la icollis (Fig.2(2,3), espec i ely), mos elemen s o he sample exhibi ambiguous mo phologies.
The ela i e a ios o ossil species we e es ablished wi h he minimum numbe o indi iduals (MNI),
also used as a quan i a i e measu e o econs uc he palaeoen i onmen . To de e mine he MNI, a
diagnos ic oo h (e.g., i s lowe mola in a icolines) o pos -c anial elemen s we e conside ed, aking
in o accoun la e ali y and sex whene e possible.
Taphonomic ema ks. The ligh o mode a e gas ic diges ion and scan b eakage obse ed in he
small- e eb a e emains, indica es ha he bones we e likely accumula ed by an a ian p eda o o
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ca ego y 15 such as a ba n owl (Ty o alba), which is an oppo unis ic a he han a selec i e hun e .
Howe e , he e a e ce ain ins ances o g ea o ex eme modi ica ion, which means ca ego ies IV o V
on And ews' scale5. In hese cases, he agen s o deposi ion we e mos p obably small-mammalian ca ni-
o es. The pa e n o skele al-elemen equency o he slow wo m, wi h lack o diges ion aces, would
co espond o in si u mo ali y. The e o e, he e a e no signs o al e a ion sugges ing ha he An oliña
assemblage is no ep esen a i e o he ecosys em in he immedia e icini y o he ca e a he ime when
he emains we e deposi ed.
Habi a weigh ings. We dis ibu e each small- e eb a e axon in he habi a (s) whe e i is possi-
ble o ind hem a p esen , especially in he Can ab ian Region8,60,61. Habi a s we e di ided in o ou
ypes3,6,7,9–11, which a e de ailed as ollows (see supplemen a y Tables 1 and 2): Fo es : ma u e woodland,
including woodland ma gins and o es pa ches, wi h mode a e g ound co e ; Meadow: e e g een open
a eas wi h dense pas u es and sui able opsoil; Wa e : s eams, lakes, ponds, and ma shes; Rocky: a eas
wi h sui able ocky o s ony subs a um. The Meadow ype, as de ined he e, is pa icula ly sui able o
he well-known humid condi ions o he Can ab ian Range60,61. Fo he es o Medi e anean Ibe ia, a
G assland o Open-d y ca ego y is equi ed.
S able ca bon and ni ogen iso ope analysis. A o al o 38 samples om AK specimens we e
analyzed, en o which we e no conside ed o in e p e a ions due o low concen a ions o collagen
(supplemen a y Table 3). Only 28 samples had C/N a omic a ios be ween 2.9 and 3.6, which indica es
good collagen p ese a ion62. The s a ig aphic dis ibu ion o he use ul samples is as ollows: e ol ed
Au ignacian (5), G a e ian (12), Uppe Solu ean (3), Lowe Magdalenian (6), and Azilian (5). Bone
collagen (coll) om ed dee (C. elaphus) long bones was ex ac ed ollowing a speci ic p ocedu e63.
Th ee-hund ed mg o bone sample powde was demine alized in 1 M HCl o 20 min a ambien empe -
a u e un il all mine als had dissol ed. Samples we e hen insed wi h dis illed wa e and 0.125 M NaOH
was added o emo e humic acid. They we e hen insed wi h dis illed wa e again and gela inized in a
pH 3 HCl solu ion o 17 h a 90 °C. The il e ed supe na an con aining he soluble collagen was hen
collec ed, ozen, and lyophilized. Collagen (2.5–3.5 mg) was loaded in o a in capsule o con inuous
low combus ion and iso opic analysis. Iso ope analyses we e pe o med o ca bon and ni ogen iso-
opes using a con inuous- low iso ope a io mass spec ome e (EA-IRMS) a Iso-Analy ical (Cheshi e,
UK). The bone collagen amoun is 12.8–0.36 %w . The Ccoll and Ncoll con en s a e abo e 25.6% and 8.2%
w espec i ely, and he C/N a omic a io is 3.2–3.6, which co esponds o well-p ese ed collagen63.
Mul iple samples o he li e s anda d NBS-1577B and ammonium sulpha e IA-R045 wo king s anda d
we e un o con i m ins umen accu acy. Replica e analysis o he NBS-1577B δ
13C s anda d du ing
uns ga e a 13C/12C o –21.65 ± 0.07 (s, n = 12); NBS-1577B δ
15N s anda d du ing uns ga e a 15N/14N
o 7.63 ± 0.14 (s, n = 12), and he IA-R045 wo king s anda d du ing uns ga e a 15N/14N o −4.70 ± 0.05
(s, n = 5).
S able oxygen iso ope analysis. Values o δ
18O we e measu ed on he shells o he plank onic
o amini e species Globige ina bulloides, and o he ben hic o amini e species Loba ula loba ula
(supplemen a y Table 4). Be ween 2 and 18 specimens pe sample we e handpicked o each species.
These indi iduals we e washed in alcohol and placed in an ul asonic cleane o less han 10 seconds
in o de o elimina e any con amina ing esidual adhe ing o he o amini e es . δ
18O da a ob ained
a e epo ed e e ed o he PeeDee belemni e (V-PDB) s anda d. Analyses we e accomplished in he
Leibniz Labo a o y o Radiome ic Da ing and S able Iso ope Resea ch (Kiel Uni e si y, Ge many) using
a “Finnigan DELTAplusXL” mass-spec ome e coupled o a “GasBench II” con inuous low in e ace,
equipped wi h a “CTC Combi PAL Au osample ”. The analy ical e o o analysis was lowe han ± 0.1‰.
Ma ine eco d. I is based on a composi e s ack o he aunis ic ( o amini e s and os acods) and
iso opic (δ
18O) analysis o wo co es om he ou e Basque shel (Sou he n Bay o Biscay): KS04-16
(43°32'66 N la i ude, 2°05'72 W longi ude, 294 m wa e dep h), aken a he eas e n lank o he San
Sebas ian Canyon, and KS05-05 (43°30'597 N la i ude, 2°13'76 W longi ude, 259 mwd.), ob ained a he
wes e n lank (see Fig.1b o loca ion, and supplemen a y Table 4 o aw da a).
The s a ig aphic amewo k o bo h co es has been p oposed elsewhe e4,28. I is based on a combi-
na ion o calib a ed AMS 14C da es and an independen local e en -s a ig aphy cons uc ed uning he
pe cen age o N. pachyde ma le coiling (sin) o he NGRIP ice co e δ
18O eco d om G eenland (wi h
he GICC05 ime-scale)45, and o he MD95-2042 ma ine sedimen a y co e δ
18O eco d om he SW
Ibe ian Peninsula shel 35. The sec ion s udied he e co e s ~35 ka ( om 43.1 ka cal BP o 7.9 ka cal BP),
wi h he loss o 3.8 ka du ing he beginning o MIS 2 (27.7–23.9 ka cal BP), and o 0.6 ka du ing HE 1
(17.1–16.5 ka cal BP) due o wo e osi e hia uses. Sedimen a ion a es ange be ween 2 and 10 cm/ka
esul ing in a ime esolu ion o app oxima ely 1400 yea s o MIS 3 in e al, ~620 yea s o MIS 2, and
~2200 yea s o he beginning o MIS 1.
In o de o s udy he ben hic and plank onic aunas, 11 samples (con inuous in e als o 5 cm) we e
analyzed om co e KS05-05, and 18 samples (in e als be ween 2 cm and 13 cm) om co e KS04-16.
Samples we e wa e -sc eened wi h a 150 μ m mesh sie e. All he os acods p esen in he samples and a
leas 300 indi iduals o plank onic o amini e s pe sample we e picked4. Se e al axonomical e e ences
