L. DONNARUMMA1,3, C. LOMBARDI2, S. COCITO2 and M.C. GAMBI1
1 Stazione Zoologica Anton Dohrn, Laboratorio di Ecologia Funzionale ed Evolutiva, Napoli, Italy
2 ENEA Centro Ricerche Ambiente Marino, La Spezia, Italy
3 present address Dipartimento di Scienze e Tecnologie, Università di Napoli “Parthenope”, Napoli, Italy Corresponding author: gambimc@szn.it
Handling Editor: Argyro Zenetos
Received: 29 October 2013; Accepted: 4 February 2014; Published on line: 28 February 2014
Abstract
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of the Mediterranean seagrass, Posidonia oceanica, have been studied at volcanic CO2YHQWVRII,VFKLD ,WDO\ XVLQJ³PLPLFV´
DVDUWL¿FLDOVXEVWUDWHV7KHH[SHULPHQWVZHUHFRQGXFWHGLQVKDOORZPosidoniaVWDQGV PGHSWK LQWKUHHVWDWLRQVRQWKHQRUWK
DQGWKUHHRQWKHVRXWKVLGHVRIWKHVWXG\DUHDGLVWULEXWHGDORQJDS+JUDGLHQW$WHDFKVWDWLRQUKL]RPHPLPLFVDQGDUWL¿FLDO
OHDYHVZHUHFROOHFWHGHYHU\WKUHHPRQWKV 6HSW 6HSW 7KHHSLELRQWVRQERWKOHDIDQGUKL]RPHPLPLFVVKRZHGFOHDU
FKDQJHVDORQJWKHS+JUDGLHQW FRUDOOLQHDOJDHDQGFDOFDUHRXVLQYHUWHEUDWHV EU\R]RDQVVHUSXOLGSRO\FKDHWHVDQGEDUQDFOHV ZHUH
GRPLQDQW DW FRQWURO VWDWLRQV EXW SURJUHVVLYHO\ GLVDSSHDUHG DW WKH PRVW DFLGL¿HG VWDWLRQV ,Q WKHVH H[WUHPHO\ ORZ S+ VLWHV WKH
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WKHDUWL¿FLDOOHDYHVDQGUKL]RPHPLPLFVRYHUWLPHVKRZHGDFRQVLVWHQWGLVWULEXWLRQSDWWHUQDORQJWKHS+JUDGLHQWDQGKLJKOLJKWHG
the peak of recruitment of the various organisms in different periods according to their life history. Posidonia mimics at the DFLGL¿HGVWDWLRQVKRZHGDSRRUDQGYHU\VLPSOL¿HGDVVHPEODJHZKHUHFDOFLI\LQJHSLELRQWVVHHPHGOHVVFRPSHWLWLYHIRUVSDFH7KLV
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consequently, on the functioning of the system.
.e\words Seagrass, epiphytes, mimics, CO2 vents, colonization pattern, recruitment, biodiversity, Mediterranean Sea.
Research Article Mediterranean Marine Science
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Introduction
The amount of CO2 in the atmosphere has steadily increased since the industrial period. According to es
timates, if greenhouse gas emissions continue to rise at current rates, the atmospheric CO2 concentration levels ZLOOEHSSPE\DQGSSPE\ ,3&&
7KHVXUIDFHRFHDQS+OHYHOPD\WKHUHIRUHIDOOWR
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crease in the ocean pH level, as a result of atmospheric CO2 GLVVROXWLRQ LQ WKH VXUIDFH ZDWHUV RI WKH RFHDQV LV
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RU³WKHRWKHU&22 SUREOHP´ 'RQH\et al.,
In particular, OA is the result of carbonic acid formation +2CO3 ZKLFKGLVVRFLDWHVWRELFDUERQDWH +&23 FDU
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cation of organisms such as corals, molluscs, and many RWKHURUJDQLVPVZLWKVNHOHWRQVDQGVKHOOVFRPSRVHGRI
FDOFLXP FDUERQDWH 5R\DO 6RFLHW\ 'RQH\ et al., 2009; Lombardi et al.,DE ,QDGGLWLRQZKHQWKH
VHDZDWHULVFRPELQHGZLWKRWKHUNLQGVRIQDWXUDODQGRU
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WKLFFRPPXQLW\VWUXFWXUH .URHNHUet al., 5RGROIR
Metalpa et al., LPSDFWLQJPRVWIXQGDPHQWDOELR
ORJLFDODQGJHRFKHPLFDOSURFHVVHV .OH\SDVet al., 2006;
Fabry et al., 0DQ\ODERUDWRU\VWXGLHVKDYHVKRZQ
that the early life stages of several organisms are also QHJDWLYHO\LQÀXHQFHGE\DFLGL¿HGVHDZDWHU .URHNHUet al., DQGWKLVKDVEHHQREVHUYHGDOVRLQin situH[
periments at CO2YHQWV &LJOLDQRet al., 2010; Ricevuto et al., +RZHYHUWKHUHVSRQVHRIPXOWLVSHFLHVDVVHP
EODJHVWR2$DWQDWXUDOO\DFLGL¿HGZDWHULVVWLOOSRRUO\
GRFXPHQWHG HVSHFLDOO\ UHJDUGLQJ KLJKO\ FRPSOH[ V\V
WHPVEXLOWE\VWUXFWXULQJKDELWDWIRUPLQJVSHFLHVVXFK
DVVHDJUDVVPHDGRZV 0DUWLQet al.,
Posidonia oceanica / 'HOLOH LV WKH HQGHPLF DQG
GRPLQDQWVHDJUDVVLQWKH0HGLWHUUDQHDQ6HD,WIRUPVH[
WHQVLYHPHDGRZVIURPWKHVXUIDFHGRZQWRDPD[LPXP
RIDERXWPGHSWK 3URFDFFLQLet al., 6WXGLHVRQ
the fauna associated to P. oceanica revealed high diver
VLW\RIVSHFLHVVHWWOHGERWKRQOHDYHVDQGUKL]RPHV 0D]
Medit. Mar. Sci., 15/3, 2014, 498-509 499 zella et al., 1992; Cocito et al., DQGEHORQJLQJWR
GLIIHUHQWWD[RQRPLFJURXSVZKLFKLQFOXGHVPDQ\FDOFL
I\LQJWD[DVXFKDVFRUDOOLQHDOJDHFUXVWDFHDQVPROOXVFV
VHUSXOLGSRO\FKDHWHVEU\R]RDQV 0D]]HOODet al., 1992;
Buia et al., 2000; Borg et al., 2006; Balata et al.,
Nesti et al.,
:LWKLQWKHPosidoniaFRPSOH[V\VWHPWKHHSLSK\WHV
settled on the leaves and the rhizomes play an important UROH LQ WKH IRRG ZHE DQG IXQFWLRQLQJ RI WKH PHDGRZV
0D]]HOODet al., 7KHHSLSK\WLFDOJDOFRPSRQHQW
UHSUHVHQWV WKH PDLQ LWHP IRU HQHUJ\ WUDQVIHU ZLWKLQ WKH
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producers to higher trophic levels through the consump
tion due to small mesoherbivores, a guild of grazers that not only fed on the system but also found shelter and SHUPDQHQWKDELWDWLQWKHPHDGRZ %UDZOH\ 7KH
animal component of the epiphytes is also consumed by RWKHU VSHFLDOL]HG LQYHUWHEUDWHV *DPEL 0RUUL DQG VKRZV LQWHUHVWLQJ H[DPSOHV RI DGDSWDWLRQ WR WKH
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Electra posidoniae
In addition, the epiphytes represent sensitive indica
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FDWLRQ 0RUUL DQG DUH DEOH WR UHFRUG WKH HQYL
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epiphytic community of P. oceanica, and especially that IRXQGRQWKHOHDYHVPDLQO\FRQVLVWVRIVKRUWOLYHGVSH
FLHVZKLFKVKRZDKLJKO\VHDVRQDOGHYHORSPHQWIROORZ
LQJWKHF\FOHRIOHDIJURZWK 0D]]HOODet al., DV
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1HVWLet al., DQGOLWHUDWXUHKHUHLQ
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phytes in relation to OA is that carried out by Martin et al. DORQJDQ2$JUDGLHQWDWQDWXUDO&22 vents off Ischia. These authors highlighted big differences in the composition and structure of the calcareous epiphytic community of P. oceanicaOHDYHVLQDFLGL¿HGVHDZDWHUV
ZKHUHFRUDOOLQHDOJDHDQGRWKHUFDOFL¿HUVZHUHVWURQJO\
UHGXFHG RU DEVHQW +RZHYHU 0DUWLQ et al. OLP
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the rhizomes.
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careous macroalgae and calcifying benthic invertebrates colonizing the hard rocky reefs, adjacent to the Posidonia VWDQGVLQWKHVDPHVWXG\DUHDZHUHVKRZQE\RWKHUDXWKRUV
+DOO6SHQFHU et al., .URHNHU et al., 2011; Porzio et al., 6RPHRIWKHSDWWHUQVREVHUYHGLQWKHDGXOW
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due to selective pressure on the larval and juvenile stages &LJOLDQRet al., 2010; Ricevuto et al.,
The overall aim of this study is to highlight the ef
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tlement pattern of the Posidonia epibiont community of the leaves and rhizomes along a gradient of pH reduction, and increased pCO2XVLQJDQHZH[SHULPHQWDODSSURDFK
ZLWK³PLPLFV´ VHH0HWKRGV *DPELet al., 2011; Cocito et al., 7KHSODQWPLPLFVZHUHXVHGWRUHGXFHWKH
LPSDFWRIH[SHULPHQWDOVWXGLHVRQWKHQDWXUDOPosidonia PHDGRZZLWKLQWKHVWXG\DUHD0RUHRYHUPLPLFVDUHHV
VHQWLDOIRUKDYLQJDQXQFRORQL]HGVXEVWUDWHWRH[DPLQH
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time interval and to compare possible quantitative and TXDOLWDWLYH GLIIHUHQFHV LQ VSHFLHV EHWZHHQ DUWL¿FLDO DQG
QDWXUDOVXEVWUDWHV LHP. oceanicaWLVVXH ,QGHWDLORXU
JRDOV DUH L WR FKDUDFWHUL]H WKH Posidonia VWDQGV ZKHUH
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SDWWHUQ RQ WKH ¿UVW WKUHH PRQWKV RI H[SRVXUH DORQJ WKH
JUDGLHQWV IRU ERWK WKH OHDYHV DQG UKL]RPH PLPLFV LLL to study the settlement pattern through time of the main HSLELRQWV OLPLWHGWRWKHVRXWKVLGHRQO\
Materials and Methods Study site
The study area is adjacent to Castello Aragonese, D YROFDQLF GRPH DQG LVOHW ORFDWHG DW WKH QRUWKHDVWHUQ
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et al., 2011; Lombardi et al., E 2Q ERWK VLGHV RI
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subjected to CO2HPLVVLRQLVSUHVHQW %XLDet al., 2003;
+DOO6SHQFHUet al., 2QWKHVRXWKVLGHWKHPRVW
intense venting activity include also PosidoniaPHDGRZ
here in some restricted areas Posidonia can reach very VKDOORZGHSWK P DQGIRUPVDVRUWRIUHHI7KLV
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direct gas bubbling is very limited or absent inside the PHDGRZ,QDGGLWLRQLQWKLVDUHDDQHFGRWDOREVHUYDWLRQV
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recent phenomenon on the north side of the Castello. The H[SHULPHQWVDUHFRQGXFWHGLQVKDOORZPosidonia stands
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VLGH 111 DQGWKUHHRQWKHVRXWKVLGH 6&6
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been selected based on previous studies in relation to SUR[LPLW\WR&22 emissions and mean pH values record
HG VHH&LJOLDQRet al., 2010 for a map of the area, Lom
bardi et al., E 7KH 6 DQG 1 VWDWLRQV DFLGL¿HG
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northern and 6.6 at the southern sites, near the rocky reef .URHNHUet al., ,QWKHVHVWDWLRQVWKHP. oceanica PHDGRZLVYHU\GHQVH RYHU VKRRWVP2 %XLDet al.,
ZLWKWKHVKRUWOHDYHVGXHWRWKHIUHTXHQWJUD]LQJE\ DURXQG +DOO6SHQFHUet al., 2008; Lombardi et al.,E EXWLWKDVDOVRDFRQVLGHUDEOHYDULDELOLW\LQ
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ogy, both rhizome and leaves have been developed ad hoc for this study. This methodology, implying the use RI DUWL¿FLDO VXEVWUDWHV LV DQDORJRXV WR WKH XVH RI SDQ
els and volcanic tiles to study the fouling, community UHFRORQL]DWLRQ DQG VXFFHVVLRQ SDWWHUQ LQ KDUG ERWWRP
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physical structure and morphology of a seagrass have DOUHDG\EHHQXVHGE\RWKHUDXWKRUV 3LQNQH\ 0LFKHOL
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propriately designed, they can simulate plant architecture and structure. So they have the merit to reduce variability RISODQWIHDWXUHVUHVSHFWWRWKHQDWXUDOFRQWH[W0LPLFV
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ture and physical structure on the epibiont community
colonization vs the biological and chemical effect. In ad
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grooved surface to reproduce the roughness of the natural rhizomes as best as possible. The length of the cylinders, set according to the rhizome mean height from literature GDWDLVFPZLWKDGLDPHWHURIDSSUR[LPDWHO\FP
*DPELet al., 2011; Cocito et al., 0LPLFVRIPosi-doniaOHDYHVDUHPDGHZLWKQRQWR[LFGDUNJUHHQÀH[
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hammered on the bottom among the Posidonia natural UKL]RPHVSURGXFLQJDPLQLPDOLPSDFWRQWKHPHDGRZ
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tographed. In order to study the pattern of settlement of Fig. 1:$UWL¿FLDOVWUXFWXUHVPLPLFNLQJWKHP. oceanica rhizome and leaves used to study colonization and settlement patterns RI WKH HSLELRQW SRSXODWLRQV$ UKL]RPH PLPLF % WKH PHWDO
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since here the pH gradient is stronger than to the north side .URHNHU HW DO $W HDFK VWDWLRQ Posidonia shoot GHQVLW\ZDVPHDVXUHGLQ6HSWHPEHUDQGVDPSOLQJV
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Results
Shoot density and morphometric analysis of Posidonia along the pH gradient
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