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Vol. 193: 241-249.20OOMARINE ECOLOGY PROGRESS SERIES
Mar Ecol Prog SerPublished February 28
Bio-mineralogy as a structuring factor for marineepibenthic communities
G. Bavestrellol'*, C. N. Bianchi2, B. Calcinai3, R. Cattaneo-Vietti3, C. Cerranos,C. Morri3, S. Puce3, M. Sarà3
rlstituto di Scienze del Mare, Università di Ancona, Via Brecce Bianche, 60131 Ancona, Italy2Marine Environment Research Centre, ENEA Santa Teresa, PO Box 316, 19100 La Spezia, Italy
3Dipartimento per lo studio del Territorio e delle sue Risorse, Università di Genova, Viale Benedetto XV 5,16132 Genova, I ta lv
ABSTRACT: The mineralogical features of the substrate were generally considered a minor factor instructudng marine benthic communities. The aim of this work is to verify whether the presence ofquartz minerals in rock may explicate differences, usually explained in terms of substrate roughness orother factors, in epibenthic communities. Laboratory tests on the hydroid Eudendrium glomeratumshowed that its planulae settle preferentially on carbonatic, rather than quartzitic, substrates. To testthe influence of quartz on established communities, we analysed the species composítion and quanti-tative structure of sublittoral sessile assemblages on different rocks in several localities of the Ligurianand Tyrrhenian seas. The observed differences appeared to be related to the presence of quartz in thesubstrate rock. The interactions between organisms and minerals (bio-mineralogy) might play a signif-icant role on benthic communities, affecting not only the initial colonlsation, but also later assemblages.This potential role has been largely neglected to date and further studies are needed to prove its impor-tance.
KEY WORDS: Substrate colonisation Mineral comoosition Marine benthos distribution . Hardsubstrates . Bio-mineralogy
INTRODUCTION
The spatial distribution and structure of marine ben-
thic communities are due to numerous abiotic and
biotic factors which, in turn, are influenced by thepresence of the organisms, in a mutual exchange ofinputs. Among the abiotic factors, the mineralogical
features of the substrate were generally considered of
scarce importance, but recent studies by Cerrano et al,(1998) have shown that the presence of quartz in the
sand may affect the initial steps of infauna colonisa-
t ion. Cerrano et al. (1998) introduced the term bio-min-
eralogy to explicate the interrelationships between
biological systems at different hierarchies (cell, organ-ism, species, community) and minerals.
Bio-mineralogy could influence hard-bottom assem-
blaqes and explain some 'anomalies' in the structure of
' E-mail: bave@promix.it
@ Inter-Research 2000
Resale of full article not permitted
communities growing on rocks of different nature. A
species assemblage, which may be slightly more
attracted to a particular substrate, could affect succes-
sion by its subsequent interaction with later assem-
blages. A similar effect was evidenced in the colonisa-
tion of artificial substrates, with respect to both species
composition and abundance (Anderson & Underwood
1994, Holm et al, 1997). Less information is avai lable
for natural substrates (McGuiness 1989), but i t is com-
mon knowledge that the softness and asperity of a rock
can favour or hamper biotic colonisation through selec-
tive larval settling, retention of water (in the littoral)
and organic matter, and provision of refuges from pre-
dation or grazing (Den Hartog 7972, Levinlon 1982,
Walters & Wethey 1996).
More is known about the influence of substrate mrn-
eraÌogy on bioboring, which is prevented by high
percentages of quartzitic or pelitic components in
the rock. Sublittoral endolitic communities are charac-
242 Mar Ecol Prog Ser 193:241,-249,2O0O
Fig. 1. Subtittoral rock showing differences in the distribution of borers due to themineral composition of the substrate. The white calcitic vein is widely bored by thesponge Cliona celata which is absent on marl limestone (grey). Herein only the date-
mussel Lithophaga lithophaga is able to penetrate (arrows)
terlsed mainly by clionid sponges and bivalves. Clionidsponges use hatching cel l pseudopodes and the pro-duction of carbonic acid to penetrate limestone (Rùt-zler & Rieger 1973, Pomponi 1979), but Cl iona celataGrant preferentially bores, in the Mediterranean Sea,substrates richer than 60%, in carbonates (unpubl.obs.). Bivalves, such as species oî Lithophaga, borewith the help of sulphuric acid and/or neutral muco-proteins (Russo & Cicogna 1992), and are also able topenetrate marl limestone, which is impenetrable bycl ionids (unpubl. obs., Fig. 1). AII this has importantconsequences on the rock texture and roughness and,ultimately, on the community structure.
To check the influence of substrate mineralogy on thelarval settling, a series of laboratory tests was conductedusing planulae of the hydroid Eudendrium glomeratum(Picard), a very common species of the sublittoral Med-iterranean zoobenthos (Boero et al. 1986). In order toseek a relation between the mineralogy of natural sub-strates and the structure of sessile epibenthic communr-t ies, the specles composit ion and percent cover of as-semblages living on different kinds of rock in thewestern Mediterranean Sea were comoared.
during November 1998 at 20 to25 m depth. The fertilised eggsdevelop in verticils of 5 to 10 fixedto a rudimentary polyp, the blas-tostyle, deprived of mouth andtentacles. Each egg is envelopedby a non-branched spadix. Theverticils of eggs were mechani-cally detached from the mothercolony and placed in 250 ml cupsfilled with filtered natural seawater at a temperature of 15'C.
Cerrano et al. (1997) demon-strated that light exposure is nec-essary to trigger egg hatching andtherefore we reared the eggs inIit conditions for 3 d. New re-leased planulae were divided into4 stocks of 60 specimens and eachstock was placed for 12 d in anexperimental Petri dish in com-plete darkness to avoid problems
related to their very high pho-
totrophy. Petri dishes were pre-pared by sticking a uniform layer
of sand grains with Eukitt; half of the surface was cov-ered by quartz sand, and half by sand derived fromCarrara marble. The 2 sand types have the same gran-ulometric (725 to 250 pm) and morphological features(roundness, 0.35 to 0.7; project ion of spherici ty, 0.8 to
MATERIAL AND METHODS
Laboralory. Planulae of the hydroid Eudendriumglomeratum were obtained from female colonies col-lected on the rocky cliff of the Portofino Promontory
Fig. 2. Geographic layout of theurian and Tyrrhenian seas
field-study sites in the Lig-(NW Mediterranean)
Bavestrello et al.: Structurinq of marine epibenthic communities 243
Table 1. Localities for field studies on sublittoral rocky bottoms
Locality Contrasted mineralogies Depthrange (m)
No. ofstatrons
No. ofspecres
Ligurian Sea
Giglio Island
Northeast Sardinia
Quartzite(Gallinaria Island)
Granite (most ofthe island)
Granite (most of thecoast and small islands)
V S Puddingstone, marllimestone and sandstone
(Portofino region)
Limestone (western partof the island)
Limestone-dolomite(Tavolara Island)
5-7
6 - 1 0
1B-34
l 4 60
r t ) 54
20 44
0.9). Both kinds of sand were previously stored at
100"C for 24 h, which enabled us to obtain an artificial
hard bottom on the entire Petri dish surface, with very
simiÌar physical features but with 2 different mineralo-
gies.
Field. The data matrices were produced using un-
published data sets on subtidal epibenthic communi-
ties of the Ligurian Sea (Gallinaria Island and Portofino
region) and Tyrrhenian Sea (Giglio Island and north-
east Sardinia) (Fig. 2). The data sets were chosen in
order to be able to contrast communities from an equal
number of stations on rocks rich in quartz, such as
quartzite and granites, or deprived of that mineral
(Table 1). All data sets consist of percent cover data of
conspicuous species (Hiscock 1987), derived from
underwater visual inventories by SCUBA divers using
quadrats (Bianchi et al. 1991). Cover data for a total of
96 species (Table 2) were available, but each data set
was analysed separately according to depth zone and
geographical location, so that communities only
showed differences in the mineralogical nature of the
substrate and possibly exposure. To avoid the influ-
ence of sedimentation, which may alter the effects
of mineralogical composition at the rock surface
(Bavestrel lo et al. 1995a), vert ical stat ions (70 to 95"
sÌope) were selected. Matrices of species cover data
were compared by correspondence analysis (Legendre
& Legendre 1998), and species numbers and total
cover by 1-way ANOVA. Prior to analysis, percentage
cover values were arcsine transformed to meet the
assumption of homogeneity of variances (Underwood
1997).Field-study sites. The Ligurian Sea data derive from
surveys carried out in shallow water at Gallinaria
Island in the summer oÎ 1991 and in the region of
Portofino Promontory in the summer of 1993. The
Tyrrhenian Sea data include information taken at
infralittoral depths around Giglio Island in September
of 19BB to 1991 and at circalittoral depths in north-
eastern Sardinia in June 1990 lTable 1ì.
The Ligurian Sea has been the object of much
research in marine biology, and many studies have
taken into account the epibenthic communities on the
rocky bottom (Bianchi et al. 1987, Cattaneo-Vietti et al.
19BB). One of the most studied sites is the region
around Portof ino (Tortonese 1958, 1962, Morri et al.
19BB), but recent research has also been done on the
Island of Gall inaria (Balduzzi et 41. 1994). These stud-
ies underlined that epibenthic communities on sublit-
toral rocks at Portofino are dominated by flourishing
gorgonian populations, whereas at Gallinaria, gor-
gonians are scarce and sponges dominate. From a min-
eralogical point of view, Gallinaria Island is exclusiveÌy
quartzit ic (Orsino 1975), whereas the coast around
Portofino is characterised by puddingstone, marl lime-
stone and sandstone, none of which has a significant
quartz component (Boni et al. 1969).
The Giglio Island is included in the southern group
of the Tuscan Archipelago, at the border between Lig-
urian and Tyrrhenian seas. Its rocky coast is mostly
granite, but a small portion on the western side is com-
posed of limestone (Alvisi et al. 1994). The subtidal
epibenthic communities of Giglio Island were first
described by Balduzzi et al. (1996).
The northeast corner of Sardinia is mostly composed
of granite. A striking exception is the Tavolara Island
made by a gigantic limestone-dolomite slab (Lorenzoni
& Chiesura-Lorenzoni 1973). Together with Molara,
Molarotto and other minor islets and rocks (all granitic),
Tavolara forms a small archipelago, the epibenthic
communities of which have been studied by Navone et
a l . (1992) .
RESULTS
Laboratory
After hatching, th.re Eudendrium glomerafum planulae
crawled on the bottom of culture vessel for 2 to 3 d. Then,
they fixed to the substrate by the anterior pole and meta-
morphosed into a planulary polyp, Data showed that
crawling planulae had a strong selectivity for the sub-
strate, being always about 5 times more abundant on the
244 Mar EcoÌ Prog Ser 1,93:241,-249, 2OO0
Table 2. List of the species in inventories of field studies on sublittoral rocky bottoms. Species codes are those used in Figs. 4,6 &7
Code Species,/familyname Phylum Code Species/familyname Phylum
Aab Acetabularia acetabulum(Linnaeus)
P, C. Silva
Aac Acanthella acufa Schmidt
Acr AmphiroacryptarthrodiaZanardini
Ada Axinella damicornis (Esper)
Ali Arbacia lixula (Linnaeus)
Aor Agelas oroides (Schmidt)
Ari Amphiroa rjErjda Lamouroux
Ave Axinella verrucosa (Esper)
Beu Balanophyll iaeuropaea(Risso)
tspo Bd ldnus per lo ra lus Brugu ière
Cad Codium adhaerens C. Agardh
Cbo Caberea boryr (Audouin et Savigny)
Cbu Codium bursa (Linnaeus) C. Agardh
Ccl Clathrina clathîus (Schmidt)
Cco ClathrinacontoÍta(Bowerbank)
Ccr Crambe c.ambe (Schmidt)
Cde Clavelina dellavallei(Zirpolo)
Cel Corallina elongata Ellis et Solander
Cfi Cellaria fistulosa (Linnaeus)
Cfr Codium fragile (Suringar) Hariot
Cgr Corallina granifera Ellis et Solander
Cin Caryophyll iainornata(Duncan)
Cla Cladophora sp.
Cln Clionidae spp,
Cmu Cutleria multifida (Smith) Greville
Cni Cliona nigricans (Schmidt)
Cnu Chondrilla nucu.la Schmidt
Cpa Chartella papyrea (Pallas)
Cpr Cladophora proltferd (Roth) Kùtzing
Cre Chondrosia renrTormis Nardo
Csp Cladostephusspongiosus(Hudson)
C. Agardh
Czo Cystoseirazosteroides(Turner)
C. Agardh
Ddi Dictyota dichotoma (Hudson) Lamouroux
Dpo Dictyopteris polypodioides (De Candolle)
Lamouroux
Dve Dasycladusvermicularis(Scopoli) Krasser
Dvr Dudresnaia vertici l lata(Withering)
Le Jolis
Hco Hemimycalecolumella(Bowerbank)
Hdi Halopteris drapàana (Heller)
Hfi Halopteris filicina (Grateloup) Kiitzing
Hpa Halocynthia paptllosa (Linnaeus)
Htu Halimeda funa (Ell is et Solander)
Lamouroux
hyd Unidentif iedhydroids
Eca Eunicella cavo.lmiì (Koch) CnidariaEra Eudendrium racemosum lGmelin) CnidariaEsr Eunicella sìngularis (Esper) CnidariaFpe Flabellia petiolata (Turra) Nizamuddin ChÌorophytaFru 'Fa lkenberg ia ru fo lanosa ' (Harvey) Schmi tz Rhodophyta
Gob Galaxaura oblungata (Ell is et Solander) Rhodophyta
Lamouroux
Ior lrcinia oros (Schmidt)
Irc fcrria sp.
Iva Ircinia variabil is (Schmidt)
Jru Jania rubens (Linnaeus) Lamouroux
Lfr Lithophyllum frondosum (Dufour) Furnari,
Cormaci et Alongi
Lin LithophyllumjncrustansPhil ippi
Lob Laurencia obfusa (Hudson) Lamouroux
Lpr LeptopsammiapruyofiLacaze-Duthiers
Lva Leucosoleniavariabil isHaeckel
Mli MesophyÌLum lichenoides (Ellis) Lemoine
Mtr Myriapora fruncafa (Pallas)
Mvu Microcosmus vulgaris Heller
Pax Parazoanthusaxinellae{Schmidt)
Pcl Paramuricea clayata (Risso)
Pco Parerythropodiumcoralloides(Pallas)
Pcr Palmophyllumcrassum(Naccari)
Rabenhorst
Pfa Pentapora fascia.lis (Pallas)
Pfi Petrosia ficiformls (Poiret)
Pft Phorbas fictitius (Bowerbank)
Pfu Pseudochlorodesmisfurcellata
(Zanardini) Borgesen
PIi Paracentrotusliyldus(Lamarck)
Pne Phyllophora neruosa (De Candolle)
Grevil le ex J. Agardh
Ppa Padina pavonica (Linnaeus) Lamouroux
Psq Peyssonneliasquantaria(Gmelin)
Decaisne
Pte Phorbas tenacior (Topsent)
Ptr Pomatocerosfriqueúer(Linnaeus)
Ptu Protula tubularia (Montagu)
Rfu Reniera fulva Topsent
Rhy Rhyncozoon sp.
Rvi Reptadeonellaviolacea(Johnston)
Sar Serpulorbisarenafia(Linnaeus)
5Ìau Schizomavella auriculata(Hassall)
Sce Smittina cervicornjs (Pallas)
Sco Sphaerococcuscoronopifolius
(Goodenough et Woodward) C. Agardh
Scu SpirastrellacuncfafrixSchmidt
Sdy Salmacina dysfed (Huxley)
Se1 Sertularella e.llisli (Deshayes et
Milne-Edwards)
s e r U n r d e n t j f i e d s e r p u l i d s
Sla Savignyella.lafonfìi(AudouinetSavigny)
S1o SchizoporellalongrirosfrisHincks
spi Unidentif iedspirorbids
Ssc Stypocaulon scoparium (Linnaeus) Kùtzing
Sse SertellaseptentrionafisHarmer
Svc Serpu la vermicu ld r is L inndeus
Svu Sargrassurn yuÌgrare C. Agardh
Vst Vermiliopsisstriaticeps(Grube)
Vut Valonia utriculadsl (Roth) C. Agardh
Wpe Wrangelia penicillata C. Agardh
Chlorophyta
Porifera
Rhodophyta
Porifera
Echinodermata
Porifera
Rhodophyta
Porifera
Cnidaria
Arthropoda
Chlorophyta
Bryozoa
Chlorophyta
Porifera
Porifera
Porifera
Chordata
Rhodophyta
Bryozoa
Chlorophyta
Rhodophyta
Cnidaria
Chlorophyta
Porifera
Phaeophyta
Porifera
Porifera
Bryozoa
Chlorophyta
Porifera
Phaeophyta
Phaeophyta
Phaeophyta
Phaeophyta
Chlorophyta
Rhodophyta
Porifera
Porifera
Porifera
Rhodophyta
Rhodophyta
Rhodophyta
Rhodophyta
Cnidaria
Porifera
Rhodophyta
Bryozoa
Chordata
Cnidaria
Cnidaria
Cnidaria
Chlorophyta
Bryozoa
Porifera
Porifera
Chlorophyta
Echinodermata
Rhodophyta
Phaeophyta
Rhodophyta
Porifera
Annelida
Annelida
Porifera
Bryozoa
Bryozoa
Mollusca
Bryozoa
Bryozoa
Rhodophyta
Porifera
Annelida
Cnidaria
Annelida
Bryozoa
Annelida
Phaeophyta
Bryozoa
Annelida
Phaeophyta
Annelida
Chlorophyta
Rhodophyta
Porifera
Cnidaria
Phaeophyta
Chordata
Chlorophyta
Cnidaria
carbonatic sediments (Fig. 3a). During the experimentaìt ime (11 d), about one-third of the planulae metamor-phosed and the number of planulary polyps reflected thenumber of planulae present in the different sections of
the dishes (Fig. 3b). The rat io between metamorphosed(settled) and crawling planulae was not significantlydif ferent in the 2 sections (43.3 r 14.6 and 45.6 + 6./" forquartz and carbonate respectively).
Bavestrello et al.: Structurinq of marine epibenthic communities 245
Aab
ACr
60È* s oo
: 4 0o
8 s o", zog
F 1 0
0
hyd pI cel cro
fru Cru S.,Dd, s n,. lor
w7e cre P ^-s ln
^", cpr cDo
Lob t *, tíi' rr."ir, I l#"t
F* , FP, ,r,
t"f Q
o'
Hlu Cc
"'rî'n ML ,,, 0", t'
iro ,,"jfax
Sco
20
R 1 8: 1 5go, tl
8 1 28 1 0l o a9 e. 9 4= 2
0
Arn | (30 90 %)
Fig. 4. Correspondence analysis on sublittoral rocky bottom
data in the Ligurian Sea (Portofino region and GallinariaIsland). The variance fraction explained by the first 2 axes is
indicated. Station points are identified by bold capital letters
according to the nature of the rock. Q: quartzite; S: sandstone;ML: marl limestone; P: puddingstone, Species points are iden-
tified by codes as in Table 2
Ligurian Sea N Tyrrhenian Sea NE Sardinia
Fig. 5. Mean (+1 standard deviation) number of species (a)
and total substratum cover (b) of the epibenthic assemblagesin the 3 study sites, according to rock mineralogy. For eachsite, quartz-rich rocks (quartzìte or granites) (tr), and rocks
poor in or deprived of quartz (8) are represented
HuC c o ̂.
LCt
An . . ChA0a
Pfi
Cnulrc
Rvi
Cad
Sar
Rhv
sprMtr
l i igwa-s*]
6 8 1 0 ' t 2
Days
Fig. 3. Response oî Eudendrium glomeratum planuÌae to dif-ferences in the mineral composition of the substrate. (a) Num-ber of crawÌing planulae on marble (o) and quartz (r) sands,(b) Number of metamorphosed planulae on the same sub-
strates. Data are the means + SE of 4 replicates
Field
The first 2 axes extracted from the correspondence
analyses on the 3 data sets were significant in all cases
(p < 0.05 according to the tables of Lebart 1975). The
fraction of the total variance represented on the plane
formed by the first 2 axes was 45.73 7o for the Ligurian
Sea data set, 43.84 % for Gigl io Island, and 32.00 % for
northeast Sardinia.
Correspondence analysis on Ligurian Sea infralit-
toral epibenthic communities showed, along the 1st
axis, a clear-cut separation of the stations of Gallinaria
Island from those of the Portofino region, the first site
being mainly characterised by quartzitic rock and the
second by dif ferent rock types (Fig. ) . AÌong the 2nd
axis, the station points of Portofino region tended to
spread around according to the nature of their rocky
bottoms, marl limestone separating at one extreme and
sandstone at the other. This last arrangement might
also reflect an exposure gradient, sandstone stations
being located at more exposed sites that the limestone
ones. However, there were station points of equally
exposed sites of Gallinaria, all on quartzitic rock,
which remained well separated from the correspond-
ing ones of Portof ino. Mean species r ichness on the
quartzitic rocks of Gallinaria was lower than on the
non-quartzit ic rocks of the Portof ino region (Fig. 5a):
!' so+l
? z s
xó 2 0
o
I 1 5
i r oo
ì 5
E s oo
o40
246 Mar Ecol Prog Ser 193:247 249,2O0O
S/aHfi P,,
Mvu
uSau Beu
cspSse
vutYsl G
I Lra
L ftel AabCbu
It
Rví QS/o
Aris | (25.74 %)
Fig. 6. Correspondence analysis on sublittoral rocky bottomdata at Giglio Island (northern Tyrrhenian Sea). The variancefraction explained by the first 2 axes is indicated. Stationpoints are identified by bold capital letters according to thenature of the rock. G: granite; L: Iimestone. Species points are
identified bv codes as in Table 2
this difference is significant (1-way ANOVA, p =
0,024), On the contrary, total substratum cover (Fig. 5b)was not signif icantly dif ferent (p = 0.119).
Results from correspondence analysis on infralit-
toral communities of Giglio Island showed a separa-tion of stationpoints along the 1st axis that was consrs-tent with the mineralogical nature of the rock,opposing l imestone to granite (Fig. 6). On the 2ndaxis, limestone station points were closely grouped,
whereas granite station points were more scattered.Looking at the species points (see Table 2 for decod-ing species names), the 2nd axis opposed encrustinginvertebrates to algae and erect or massive inverte-brates: the first assemblage was considered the resultof excess sea-urchin grazing by BaÌduzzi et al. (1996).
Both the number of species (Fig. 5a) and total cover(Fig. 5b) were severely reduced on granite as com-pared with l imestone ( l-way ANOVA, p < 0.001 in
both cases).Correspondence analysis on circalittoral epibenthic
communities of northeastern Sardinia (Tavolara andMolara Archipelago) showed again the separationbetween carbonate (limestone-dolomite) and granite
station points (Fig. 7). On the contrary, no relationshipwas evident with depth, notwithstanding the compara-tively great range investigated (18 to 34 m). Also in thiscase, the number of species on granite was lower thanon limestone-dolomite (Fig. 5a) and, although small,the difference was significant (1-way ANOVA, p =
0.043). In contrast, no dif ference was found for totalcover (p = 0.717).
Lpl
LDLD
I
îfiL D -
LD
Pco
Pla
Dve A0r G
Pcllor
tu is l (18.57 %)
Fì9. 7. Correspondence analysis on sublittoral rocky bottomdata in northeastern Sardinia (Tavolara and Molara Archipel-ago). The variance fraction explained by the first 2 axes isindicated. Station points are identìfìed by bold capital lettersaccording to the nature of the rock. G: granite; LD: limestone-dolomite. Species points are identified by codes as in Tabìe 2
DISCUSSION
The structure of hard bottom communities has been
traditionally interpreted as mainly the result of com-plex biotic interactions within adult assemblages(Connell 1983, Schoener 1983). Only in the last
decade has the importance of external factors, such asphysical processes and recruitment vagaries, beenful ly recognised (Barry & Dayton 1991, Bingham 7992,
Bianchi 1997, Guichard & Bourget 1998, Smith & Wit-man 1999). However, our knowledge about the role ofthe nature of substratum remains anecdotal. Manygeneral papers on marine ecology report on the influ-
ence of hard substratum surface texture and physico-
chemical properties upon community composition and
structure (Den Hartog 1972, Levinton 1982), but stud-ies providing direct evidence are scarce. Comparing
the epibiotic communities of different types of sub-
stratum, Connell & Glasby (1999) found differences in
the identity of species and the abundance of individ-
ual taxa. The same authors observed that the charac-
teristics of the substratum surface were an importantdeterminant in the structure of assemblages and thatcertain physical or chemical properties (e.9. alkalin-ity) may affect the settlement, growth or survival of
organisms. On the other hand, Caffey (1982) found no
effect of rock types on the settlement or survival of
the intertidal barnacle Tesseropora rosea (Krauss).
Our experiments with the subtidal hydroid Euden-
drium glomeratum suggest that the larvae of benthic
organisms could be selected, other environmental con-
ClnCni
C n t nLD '"
LD HPaMtr LD S/o Ddi
INE Sard in ia ]
Cclt,
* " G
Rhvy udiDdi CcrPtu
Eca tttu ,"" G Ave
Foe Aac G ^ùce _-,,,.' l Ada u^ .r,
,n .L q ^ U a , , ' , C b u^ U u P D a
LD G " ,u, G;l' ?r,pht î^^ 56v Pne
vyo Aab
G
. 4
- . C n i,et
, lL . ì , 1
1 Lfrn,,. Goó" ' "
Pf t IMIi t,.
npaCel
Aor 1VC
Pca4
L
Pfl
AN
L
Ada
I PPa
I utuCgt Atib F p e IPIi L
6 l o r lPax
Goó |oft Pli
lva
He
'Ip la ollarlsa^pg) suipro zupnb a^lossrp pup lrallor ol
alqp sr srurtoluat prsoJpuotD a6uods aurJprrr aq] ssal-ar{uo^aN u^\ou{ lou sr esrlrs alelncrlred Jo soouodsÀq e>1e1dn aql pup uorlnlossrp oql 6ur^,\olle rusru€qJoru
IpJrruar{Jorq aql /alpp o1 salnrrds pue sruolprp paluau-rpas pup slood aq1 Jo ruolloq aql Jo pups cqrzlrenb
aqJ sr oornos ecqrs À1uo oql lplrqpq s1t{l uI 'urpr aarJ-€Jr-1s À1e1e1duroc Àq Àpo pelp; slood re1e.r,t Àrerodruol ur
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248 Mar Ecol Prog Ser 1,93:247-249, 20O0
1995b), probably due to a considerable product ion of
ascorbic acid (Cerrano et a l . 1999).
The results of this study and the above considera-
tions suggest that bio-mineralogy is likely to play a
major role on benthic communities, selecting the biota
and affecting not only the initial colonisation, as seen
in the experiment of Eudendrium settlement, but also
Iater assemblages, as apparent from our field data.
This potentiaÌ role has been largely neglected to date
and further studies are needed to prove its importance.
Acknowledgemenfs. This research was financially supportedby MURST Italian funds. Field activity received support fromENEA. Many thanks are due to all colleagues that helpedduring underwater work.
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Submitted: February 26, 1999; Accepted: September 21, lgggProofs received from author(s): February 14, 2000