organic chemistry of embalming

NATURE | VOL 413 | 25 OCTOBER 2001 | www.nature.com 837

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.................................................................Organic chemistry of embalmingagents in Pharaonic andGraeco-Roman mummiesStephen A. Buckley & Richard P. Evershed

Organic Geochemistry Unit, Biogeochemistry Research Centre, School of

Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK..............................................................................................................................................

Chemical treatments were an essential element of ancient Egyp-tian mummi®cation. Although the inorganic salt natron is recog-nized as having a central role as a desiccant1, without theapplication of organic preservatives the bodies would havedecomposed in the humid environment of the tombs2. Thenature of the organic treatments remains obscure, because theancient Egyptians left no written record of the process. Secondarytextual evidence for mummi®cation is provided by Herodotus3,Diodorus Siculus4, Strabo5 and Pliny6. The most important

account is that of Herodotus3 (about 450 yr BC), although archaeo-logical evidence shows that by this time the process had declinedsigni®cantly and the best results had been achieved centuriesbefore7. His account mentions myrrh, cassia, palm wine, `cedar oil'(still widely disputed8±10) and `gum'; however, it is vague withrespect to the speci®c natural products used. Here we report theresults of chemical investigations of a substantial collection ofsamples of tissues, wrappings and `resinous/bituminous' materi-als from provenanced and dated Egyptian mummies. We focusedon examples of the `classic' mummy-making culture of thePharaonic or dynastic period, from which we can begin to trackthe development of mummi®cation chronologically.

Studies of the organic materials used in mummi®cation werecarried out earlier in the last century (for example, see refs 11±13),but the analytical techniques available limited their ability toidentify aged, complex organic mixtures (that is, the `resins',spices, and so on). To gain a proper understanding of the mummi-®cation process and its development, it is vital to study securelyprovenanced and dated mummies using modern investigativechemical techniques. Only four such studies (which includes oneperformed in our own laboratory) have been carried out in recent

Table 1 Provenance and date of mummies, origin of balm samples and their chemical composition

Mummy¶ Date/age Provenance Sample location and description# Inferred components ofembalming `resin'I

Relativeabundance (%)**

...................................................................................................................................................................................................................................................................................................................................................................

Male adult* (`Khnumnakht')21471

1985±1795 yr BC

(XII dynasty)Rifeh Resin/tissue/bandaging Fat/oile

Proteinaceous material90%10%

Female adult²1909.527

1650±1550 yr BC

(XVII dynasty)Qurna, Thebes Resin/tissue from head of right tibia Fat/oilc

Coniferous pitchBalsam (?)

99%1%

Trace

Child (sex ?)²1909.527

1650±1550 yr BC

(XVII dynasty)Qurna, Thebes Unspeci®ed bone and cartilage Fat/oilb

Coniferous pitchBalsam (?)

82%1%16%

Head (sex ?)³1976.159.267

1550±1069 yr BC

(XVIII±XX dynasties)Thebes Skin/resin from back of cranium Fat/oilg

A sugar/gumConiferous resin

Balsam (?)

95%0.3%2%2%

Male adult§ (`Horemkenesi')Ha 7386

1069±945 yr BC

(XXI dynasty)Deir el Bahri, Thebes Resinous material from left side of

top of spineFat/oill 100%

Female(?) adultkEA74303

1069±664 yr BC

(XXI±XXV dynasties)Thebes? Resin from chest cavity Fat/oilk

Coniferous resin/pitchBalsam (?)Beeswaxn,s

61%6%

1.5%31%

Female adult§ (`Neskhons')H 5062

945±715 yr BC

(XXII dynasty)Thebes Resin-soaked outer wrapping from

left side of neckPlant oild

Coniferous resinTriterpenoid resin ?

Balsam (?)Wax

82%0.5%4%

0.9%11%

Male adult³ (`Pedeamun')1953.72

664±404 yr BC

(XXVI±XXVII dynasties)Thebes Resin from top of cranium Fat/oilm

Coniferous resinBalsam (?)Beeswaxo,t

61%0.2%1.5%38%

Female adult²1956.352

332±30 yr BC

(Ptolemaic)Thebes Resin attached to linen thread on

right ankleFat/oilf

Pistacia resinBalsam (?)Beeswaxp,u

6%6%

0.4%87%

Male adult (1)²1911.2101

30 yr BC to AD 395(Roman)

Hawara Resin-soaked outer wrapping belowright scapula

Fat/oili

Coniferous resinBalsam (?)Beeswaxq,v

78%16%Trace6%

Male adult (2)²1911.2102


Hawara Resin from side/base of left foot Fat/oila

Coniferous resinBalsam (?)Beeswaxr,w

35%37%0.2%27%

Male child (wrapped)²1956.357b


Thebes Resin on outer wrapping from areabetween calves

Fat/oilh

Coniferous resin90%9%

Male child (unwrapped)²1956.357c


Thebes Resin from abdominal cavity (kidneyarea)

Fat/oilj

Coniferous resinBalsam (?)

87%13%0.1%

...................................................................................................................................................................................................................................................................................................................................................................

Several samples were taken from all but one mummy (unwrapped male child). For example, 15 different samples were analysed from various parts of the body of Horemkenesi.* Manchester Museum; ² National Museum of Scotland; ³ Liverpool Museum; § Bristol Museum; k British Museum.¶ Museum number.# The term `resin' denotes physical appearance and does not presuppose any chemical composition or biological origin.I Superscript letters (a±w) refer to the histograms shown in Fig. 1.** Percentage relative abundance based on absolute concentrations, calculated on the basis of internal standards added at the extraction stage. Compositions do not imply that they were the originalformulations of the embalmers, owing to possible chemical changes over time.

© 2001 Macmillan Magazines Ltd

times14±17.This study involves the ®rst systematic chemical investigation of a

collection of provenanced Egyptian mummies dating from the mid-dynastic period (c. 1,900 yr BC) to the late Roman period (AD 395),which encompasses the period at which the mummi®cation processwas at its peak (1,350±1,000 yr BC). We have used diagnostic markercompounds that are present in the original `balms', are resistantto degradation and can be related to speci®c embalming agents.Gas chromatography with mass spectrometry (GC-MS) and ther-mal desorption (TD)- or pyrolysis (Py)-GC-MS facilitate themolecular separation and identi®cation of the marker compounds.

Because of the probable nature, possible processing and burialhistory of embalming materials, both free and polymerized com-ponents are likely to be present. Therefore, this `dual' approachallows the characterization and identi®cation of both the free(solvent-extractable) marker compounds and the recognizablesubunits of polymeric materials not amenable to the more conven-tional GC-MS approach17. Given the understandable sensitivitysurrounding the study of mummies, the amount of sample requiredis an important consideration. Sequential TD-GC-MS and Py-GC-MS require very small sample sizes (, 0.1 mg), facilitating thevirtually non-destructive analysis of valuable museum specimens.

A summary of the results of this study is given in Table 1. Themain products seen in all mummies are degraded acyl lipids, whichare derived from plant oils and animal fats (Fig. 1a±m). Where

samples were taken directly from the bodies, these may well derivefrom endogenous body lipids, such as triacylglycerols from fats orcell-membrane phospholipids. But even after accounting for decay,for the most part these display non-human fatty-acid distributions.In cases where degraded fats or oils are, for example, seen in thebandaging and are not directly in contact with the body, they mustderive from their intentional application as part of the embalmingprocess.

In most cases, the fatty-acid distributions (Fig. 1) are indicative ofplant origins; that is, they have a high abundance of C16:0 comparedwith their abundance of C18:0. But it is not possible to assign aprecise plant origin on the basis of fatty acids alone, owing todegradation of the major unsaturated components; such degrada-tion is evident from the presence of mono- and dihydroxycarboxylicacids, which are indicative of autoxidation. The presence of plantoils (and to a lesser extent animal fats) suggests that they were keyingredients in mummi®cation, and were probably used as a less-costly base with which to mix and apply more exotic embalmingagents to the bodies and/or wrappings.

Their widespread use indicates that the embalmers were aware ofthe special properties of unsaturated oils and fats that allow them to`dry', or rather, to polymerize spontaneously18 (later also appre-ciated by the oil painters of western Europe). This polymerizationwould have produced a highly crosslinked aliphatic network, whichwould have stabilized otherwise fragile tissues and/or textile

letters to nature

838 NATURE | VOL 413 | 25 OCTOBER 2001 | www.nature.com

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Figure 1 Chemical analyses of samples taken from the mummies in this study.

Histograms show the distribution of fatty acids of equal carbon number in acid fractions

(a±m; see Table 1), hydrocarbons of odd carbon number in neutral fractions from

samples containing beeswax (n±r), wax esters of even carbon number in neutral fractions

from samples containing beeswax (s±w).


wrappings against degradation by producing a physico-chemicalbarrier that impedes the activities of microorganisms.

The results from the wide date range of the mummies investigatedreveal notable trends in the evolution of the use of other commod-ities (Fig. 2). For example, beeswax and coniferous resin clearlyincrease in their prominence through time, and are found inmaterial taken both directly from the bodies and from the wrap-

pings. Coniferous resin is identi®ed by the presence of bothfunctionalized and defunctionalized diterpenoid components. Forexample, 7-oxodehydroabietic acid and 15-hydroxy-7-oxodehydro-abietic acid were usually the dominant diterpenoid components,and the normally abundant dehydroabietic acid was virtuallyabsent.

Although coniferous resins were clearly used in the embalmingprocess at least as early as 2,200 yr BC (VI dynasty)16, their usebecomes most apparent in later periods; both the tissues and thewrappings of mummies from the Roman period (30 yr BC to AD 395)contain appreciable quantities (up to 37%) of coniferous diter-penoids. The increasing use of coniferous resin suggests that theembalmers may have become aware of the ability of speci®c naturalproducts to inhibit microbial degradation by means of mechanisms(physico-chemical barriers and antimicrobial action) analogous totheir protective roles in the plants from which they derived.

A signi®cant trend is also seen in the use of beeswax, which ischaracterized chemically by alkanes (C25±C33) (Fig. 1n±r), waxesters (C40±C50) (Fig. 1s±w) and hydroxy wax esters (C42±C54). It®rst appears notably later than coniferous resin, with its positiveidenti®cation in a resinous coating taken from the chest cavity of afemale mummy of the Third Intermediate Period (XXI to XXVdynasty; 1,069±664 yr BC). In a sample taken from `Pedeamun', aXXVI dynasty (664±525 yr BC) mummy, the solvent-soluble extractscomprise 38% beeswax (Fig. 3). But an even greater amount wasfound in a very extensive black `resinous' layer from a femalemummy of Ptolemaic date (332±30 yr BC) (Fig. 4), in which beeswaxmade up 87% of the solvent extractable components; in otherwords, this treatment was essentially beeswax mixed with a smallamount of Pistacia resin (see also below). The choice of beeswax wasclearly motivated by its hydrophobic/sealant and antibacterialproperties, notwithstanding its symbolic signi®cance19.

Other components of the embalming `resin' are triterpenoids andhydroxyaromatic acids, which are diagnostic of plant products. The

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2500yr BC

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500yr BC

500yr AD

02000yr BC

1000yr BC

Date

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mod

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Beeswax

Coniferresin

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resin

Plant oil

Bitumen

Balsamic (?)resin*

1 1 111 1

11,21,41

111 1,21,4

24

1113 1 12

1 14

Figure 2 The use of organic commodities (preservatives/unguents) identi®ed in chemical

investigations of the `balms' of provenanced and dated ancient Egyptian mummies. Grey

scale re¯ects the relative abundance of a particular commodity found in the balm

samples, with darker shades representing a higher relative abundance. Asterisk, tentative

identi®cation of balsamic resins; 1, data from this study; 2, data from ref. 14; 3, data from

ref. 16; 4, data from ref. 15.

25105 15 20

C40

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31

C29

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C30

:0C18

:0

IS

C7 C

8

C10

C9

C6

5 10 15 20

O

CO2H

CO2H

Figure 3 Reconstructed total-ion chromatogram of the trimethylsilylated neutral fraction

(after solvent extraction and fractionation) of `resin' from the top of the cranium of the Late

period male adult `Pedeamun', XXVI to XXVII dynasty (664±404 yr BC). Peak identities

(x indicates carbon chain length): ®lled triangles, Cx :0 indicates saturated fatty acid methyl

esters; ®lled squares, Cx :0 indicates saturated lactones (carbon chain length x is followed

by the position of the lactone ring); ®lled circles, Cx indicates alkanes; open circles, Cx

indicates alkanols; ®lled inverted triangles, Cx indicates wax esters; open inverted

triangles, Cx OH indicates hydroxy wax esters; IS, internal standard (n-tetratriacontane).

Inset displays a reconstructed total-ion chromatogram of the trimethylsilylated acid

fraction (after solvent extraction and fractionation) of this sample. Peak identities: open

triangles, Cx :0 indicates saturated fatty acids; open squares, Cx indicates a,v-dicarboxylic

acids; open diamond, vanillic acid. Also shown are the structures of two diterpenoid

acids identi®ed: dehydroabietic acid and 7-oxodehydroabietic acid. IS, internal standard

(n-heneicosanoic acid).


former include the isomasticadienonic, masticadienonic, moronicand oleanonic acids that are diagnostic of the presence of Pistaciaresin18 and are found in the Ptolemaic female mummy (Fig. 4). ThePistacia content is signi®cant, constituting 6% of the extractablelipids. Triterpenoid acids, including a prevalence of dammaranesthat can occur in highly degraded Pistacia resins20, were present insigni®cant quantities (4%) in the wrappings of the XXII dynasty(945±715 yr BC) mummy `Neskhons'. However, the absence ofmoronic acid (which is used often to characterize Pistacia) leavesits precise botanical origin uncertain.

It is less easy to assign an origin to the hydroxy aromatic acids, butthese are clearly plant derived. Although sawdust was often used topack the cavities of mummies, the derivation of these acids fromlignin is unlikely as there were no detectable lignin building-blockcompounds (methyl, ethyl, n-propyl and vinyl guaiacols) in any ofthe Py-GC-MS analyses. Present in ten of the mummies, theirdistribution is generally dominated by 4-hydroxy-3-methoxyben-zoic acid with smaller amounts of p-hydroxybenzoic acid, which isconsistent with oxidation of either unsaturated C-3 side chains(either carboxyl or hydroxyl substituted) in the aromatic benzoateester of balsamic resins or ferulic acidÐa principal component ofUmbelliferae21.

The absence of the precursor compounds is not unexpected,given the susceptibility of these to the oxidation that is prevalent inmummies. Whereas low abundances of the components mayoriginate from dissolved organic matter in the Nile water used inwashing the bodies, higher concentrations, such as 16% in the XVIIdynasty child mummy, would be consistent with a plant-resintreatment. The choice of these latter natural products by the ancientembalmers again points to their recognition of the antibacterialproperties22 of these substances and hence their vital role in themummi®cation process.

Our results show that a mixture of commodities, with a composi-

tional diversity greater than reported previously, was used. The useof drying oils was clearly widespread, with coniferous resins andbeeswax increasing in importance with time. Notably, despite thefrequent and rather indiscriminate use of the term `bitumen' inconnection with mummi®cation, the idea that its general use inembalming has now been proved ``unequivocally''23 cannot besupported. In repeated searches, the steranes and hopanes char-acteristic of petroleum bitumens14,24 were not detected, which leadsus to the conclusion that natural bitumens were not used in thesemummies.

Furthermore, given that beeswax generally constitutes the greaterproportion of the organic materials rather than the resins, the termembalming `wax' has at least equal validity to so-called `resin'. In thisrespect it is especially interesting to note that the Coptic (directlyderived from the ancient Egyptian language) word for wax is in fact`mum'25. These results clearly show that, despite statements to thecontrary10,23, we do not know all there is to know about Egyptianmummi®cation, and caution needs to be exercised when makingassumptions about the materials that the ancient Egyptian embal-mers might have used. M

Received 30 May; accepted 31 August 2001.

1. Sandison, A. T. The use of natron in mummi®cation in ancient Egypt. J. Near Eastern Studies 22, 259±

267 (1963).

2. Hunter, J., Roberts, C. & Martin, A. in Studies in Crime: An Introduction to Forensic Archaeology 63±78

(Batsford, London, 1996).

3. Herodotus The Histories (trans. De SeÂlincourt, A.) Book II, 160±161 (Penguin, Harmondsworth, 1954).

4. Diodorus Siculus The Library of History (trans. Oldfather, C. H.) (Heinemann, London, 1935).

5. Strabo The Geography (trans. Jones, H. L.) (Heinemann, London, 1932).

6. Pliny (the Elder) Natural History (trans. Rackham, H.) (Heinemann, London, 1968).

7. Smith, G. E. & Dawson, W. R. Egyptian Mummies (Allen & Unwin, London, 1924).

8. Baumann, B. B. The botanical aspects of ancient Egyptian embalming. Econ. Bot. 14, 84±104 (1960).

9. Lucas, A. `̀ Cedar''-tree products employed in mummi®cation. J. Egypt. Archaeol. XVII, 13±21 (1931).

10. Mendelsohn, S. The mortuary crafts of ancient Egypt. CIBA Symposia 1795±1804 (1944).

11. Lucas, A. A preliminary note on some preservative materials used by the ancient Egyptians in

connection with embalming. Cairo Sci. J. II, 133±147 (1908).

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840 NATURE | VOL 413 | 25 OCTOBER 2001 | www.nature.com

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2015 25

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CO2HCO2H

CO2H

CO2HCO2H

HO

Figure 4 Reconstructed total-ion chromatogram of the trimethylsilylated neutral fraction

(after solvent extraction and fractionation) of `resin' attached to linen thread on the right

ankle of a female adult from the Ptolemaic period (332±30 yr BC). Peak identities

(x indicates carbon chain length): ®lled triangles, Cx:o indicates saturated fatty acid methyl

esters; ®lled circles, Cx indicates alkanes; open circles, Cx indicates alkanols; ®lled

inverted triangles, Cx indicates wax esters; open inverted triangles, Cx OH indicates

hydroxy wax esters; IS, internal standard (n-tetratriacontane). Inset displays a

reconstructed total-ion chromatogram of the trimethylsilylated acid fraction (after solvent

extraction and fractionation) of this sample, showing the structures of the Pistacia

triterpenoids identi®ed: moronic acid, oleanonic acid, hydroxyoleanonic acid,

isomasticadienonic acid and masticadienonic acid.


12. Spielmann, P. E. To what extent did the ancient Egyptians employ bitumen for embalmimg? J. Egypt.

Archaeol. XVIII, 177±180 (1932).

13. Zaki, A. & Iskander, Z. Materials and methods used for mummifying the body of Amentefnekht,

Saqqara 1941. Ann. Serv. Antiquites Egypte XLII, 223±255 (1943).

14. RullkoÈtter, J. & Nissenbaum, A. Dead Sea asphalt in Egyptian mummies: molecular evidence.

Naturwissenschaften 75, 618±621 (1988).

15. Colombini, M. P., Modugno, F., Silvano, F. & Onor, M. Characterization of the balm of an Egyptian

mummy from the seventh century B.C. Stud. Conserv. 45, 19±29 (2000).

16. Koller, J., Baumer U., Kaup Y., EtspuÈler, H. & Weser, U. Embalming was used in Old Kingdom. Nature

391, 343±344 (1998).

17. Buckley, S. A., Stott, A. W. & Evershed, R. P. Studies of organic residues from ancient Egyptian

mummies using high temperature-gas chromatography-mass spectrometry and sequential thermal

desorption-gas chromatography-mass spectrometry and pyrolysis-gas chromatography-mass

spectrometry. Analyst 124, 443±452 (1999).

18. Mills, J. S. & White, R. The Organic Chemistry of Museum Objects 2nd edn (Butterworth-Heinemann,

Oxford, 1994).

19. Raven, M. J. Wax in Egyptian magic and symbolism. Oudheidkundige Mededeelingen uit het

Rijksmuseum van Oudheden te Leiden 64, 7±47 (1983).

20. van der Doelen, G. A., van den Berg, K. J. & Boon, J. J. Comparative chromatographic and mass

spectrometric studies of triterpenoid varnishes: fresh material and aged samples from paintings. Stud.

Conserv. 43, 249±264 (1998).

21. Serpico, M. & White, R. in Ancient Egyptian Materials and Technology (eds Nicholson, P. T. & Shaw, I.)

430±474 (Cambridge Univ. Press, Cambridge, 2000).

22. Barber, M. S., McConnell, V. S. & DeCaux, B. S. Antimicrobial intermediates of the general

phenylpropanoid and lignin speci®c pathways. Phytochemistry 54, 53±56 (2000).

23. Bahn, P. G. The making of a mummy. Nature 356, 109 (1992).

24. Connan, J. & Dessort, D. Du bitume dans des baumes de momies eÂgyptiennes (1295 av. J.-C. -300 ap.

J.-C.): deÂtermination de son origine et evaluation de sa quantiteÂ. C. R. Acad. Sci. Paris II 312, 1445±

1452 (1991).

25. Granville, A. B. An essay on Egyptian mummies, with observations on the art of embalming amongst

the ancient Egyptians. Phil. Trans. R. Soc. Lond. 115, 269±316 (1825).

Acknowledgements

We thank S. Giles of Bristol Museum; J. Spencer and J. Taylor of the British Museum;J. Hayward of Liverpool Museum; R. David of Manchester Museum; and K. Eremin of theNational Museum of Scotland for making the samples available to us. We thank J. Fletcherfor advice on aspects of Egyptology; and J. Carter and A. Gledhill for technical assistance.NERC provided ®nancial support for mass spectrometry facilities.

Correspondence and requests for materials should be addressed to R.P.E.

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.................................................................Local interactions predict large-scalepattern in empirically derivedcellular automataJ. Timothy Wootton

Department of Ecology & Evolution, The University of Chicago, Chicago,Illinois 60637, USA

..............................................................................................................................................

An important unanswered question in ecology is whether pro-cesses such as species interactions that occur at a local scale cangenerate large-scale patterns seen in nature1,2. Because of thecomplexity of natural ecosystems, developing an adequate theo-retical framework to scale up local processes has been challenging.Models of complex systems can produce a wide array of outcomes;therefore, model parameter values must be constrained byempirical information to usefully narrow the range of predictedbehaviour. Under some conditions, spatially explicit models oflocally interacting objects (for example, cells, sand grains, cardrivers, or organisms), variously termed cellular automata3,4 orinteracting particle models5, can self-organize to develop complexspatial and temporal patterning at larger scales in the absence ofany externally imposed pattern1,6±8. When these models are basedon transition probabilities of moving between ecological states ata local level, relatively complex versions of these models can belinked readily to empirical information on ecosystem dynamics.Here, I show that an empirically derived cellular automaton

model of a rocky intertidal mussel bed based on local interactionscorrectly predicts large-scale spatial patterns observed in nature.

Mussel beds characterize many temperate, rocky intertidal shoresthroughout the world9, and can exhibit complex patterning. Thispatterning is thought to result from the interplay between inter-actions among sessile species and external disturbance agents,particularly large waves10±15. Along the Paci®c coast of NorthAmerica, California mussels (Mytilus californianus) seem to interactlocally with other organisms in two ways. First, mussels invadebare rock or displace species adjacent to them by overtoppingtheir neighbours as they grow, and by creeping into adjacent areasby means of sequential attachment of new byssal threads inuncolonized areas as old byssal threads in colonized areas breakor become detached12. Second, because mussels attach to each otherwith byssal threads, when waves dislodge a mussel from the rockthat mussel pulls its neighbours along with it, thereby transmittingthe disturbance through the mussel bed in much the same way asforest ®res propagate when sparks from a burning tree igniteneighbouring trees12. Wave disturbance also acts differentially onmussel beds of different ages, with beds of old, multi-layeredmussels being more prone to disturbance, owing to the high ratioof mussel mass per unit attachment area to the rocks, and to thehigh fraction of byssal threads attached to other mussels, rather thanthe rock12,14,15. Other sessile species and their mobile associatescolonize the bare rock created by disturbance events, and exhibita complex set of interactions among themselves and withmussels10,12,13,16±19. Because of its rapid dynamics and macroscopicorganisms of modest size and mobility, the rocky intertidal zone isan unusually tractable model system in ecology for experimentalinvestigations and for readily observing spatial and temporaldynamics in a complex natural ecosystem19. These features makemussel beds particularly suitable for the purpose of developing andtesting different versions of models with empirical parameters, suchas cellular automata.

Data on the dynamics of mussel beds were collected over a six-year period (May 1993 to May 1999) at 1,400 ®xed points in themussel bed of Tatoosh Island in Washington State20. The data weretaken from 14 quadrats (60 ´ 60 cm) positioned with ®xed corner

Figure 1 Photograph of spatial patterning in the mussel bed of Tatoosh Island,

Washington.


organic chemistry of embalming

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