Rivista Italiana di Paleontologia e Stratigrafia ltprile 1997 ENVIRONMENTAL EVOLUTION OF THE LONGARINI AND CUBA LAGOONS (SOUTHEASTERN SICILY) CONCETTO AMORE*, BARBARA COSTA*, GIOVANNI RANDAZZO*'I & ANGIOLA ZANINI* Key-uords: Lagoonal environment, Paleoecology, ltaly, Sout- heastern Sicily. Riassunto. I pantani I-ongarini e Cuba rappresentano le mag- giori superfici umide del sistema retrostante la Costa dell'Ambra nel- la Sicilia sudorientale: la loro evoluzione è stata ricostruita mediante lo studio comparato delle caratteristiche tessiturali, composizionali e faunrstiche dei sedinenti, evidenziando facies lagunari a diverso gra- do di "confinamento". I piani più antichi sono cxatterizzati da un ambiente lagunare con sedimenti prevalentemente peliticr e con asso- ciazioni faunistiche riconducibili alla zonazione biologica proposta per gli ambienti paralici attuali da Guelorget 6c Penhuisot (1983). Nei piani più recenti si ha un'accentuazione delle caratteristiche lagu- nari, legata anche alla maggiore influenza degli apponi solidi prove- nienti dal retrostante bacino idrografico. Abstract. The hngarini and Cuba lagoons are the largest we- tlands in a system of lagoons located inland of the Ambra Coast in southeàstern Sicily. A reconstruction of their evolution through a comparative study of textural, compositional and faunal data, showed facies of a lagoonal system influenced differently and in va- rying degrees by rivers and sea. The oldest layers are made of lagoo- nal pelitic sediments containing faunal assemblages (mixed bioceno- ses) referable to the zonal classification of the paralic envrronment proposed by Guelorget & Perthuisot (1983). In the more recent layers an environmental change is recorded, showing an increase ìn lagoonal characteristics and a decrease in "mìxed" biocenoses, due to a Breater input of solid materials from the adjacent hydrographic basin. Introduction, Research on the Sicilian p^raIic environments has been conducted since 1991 (Amore et al. 1991, L994). The present study focuses on the lagoons of the Ambra coast between the towns of Pachino and Ispica. The coastal lagoons of southeastern Siciiy repre- sent an important element from a social and naturalistic asset. They are located adjacent to a densely populated area rich in tourist facilities and are surrounded by vi- neyards and vegetable gardens. In particular, together with the nearby Vendicari lagoons, they provide a regu- lar stopping-piace for birds migrating from northern Eu- rope to north Africa. Only the Longarini and Cuba lagoons have been studied among the many wetlands ("Pantani') developed along the Ambra coast (Fig. 1). The Longarini lagoon (3 km2 surface aîd 20 cm deep) communicates with the sea through two partially occluded artificial canals. The Cuba lagoon (0.7 km'z surface and 1 m deep) is comple- tely separated from the sea by a 5 m high ridge of du- nes. The tlvo lagoons are locarcd on the southeastern edge of the Hyblean calcareous plateau. The hydrographic basins of the I-ongarini and Cuba lagoons encompass the foliowing Miocene-Quater- nary formations: Middle-Upper Miocene marls of the Tellaro Formation, the Lower Pliocene marls of Trubi, calcarenites, Middle Pliocene calcirudites and marls, I-ower Pleistocene calcarenites and sands, Middle-Upper Pleistocene sands, biocalcarenites and conglomerates, and Flolocene fluvial, marsh and coastal deposits. As a consequence, the soiid input (Fig. 2) consists of: 1) pelitic granulometries due to predominantly mar- ly-muddy deposits of Middle-Upper Miocene (Tellaro Formation), of Lower Pliocene (Trubi) and of Middle Piiocene, and holocenic alluvial sediments, and 2) san- dy-ruditic granulometries due to alternations of Lower- Pleistocene calcarenites-sands and middle to Upper Plei- stocene sands-calcarenites and conglomerates. The solid input occurs prevalently during the au- tumnal-winter rains, following the hot dry mediterra- nean summers. In this area, winds blow from the West and North-East; and the mean air temperatures range from L2oC in January and December to 26"C in July and August. The mean annual precipitation averages 385 mm, ranging from as little as 0 mm per month from June to August to as much as 60 mm per month from October to January (Istat, 1988), with consequent seaso- nal variations of water levels in the lagoons. The hydrological characteristics of the water re- flect the predominant carbonate composition of the '' Istituto Policattedra di Oceanologìa e Paleoecologia, Università degli Studi di Catania, Corso Italia, 55 - 95129 Catania, Italia 'r'f Istituto di Scienze della Terra, Università degli Studi di Messina, Salita Sperone, 11- C.P54 - 98166 S. Agata di Messina. C. Amore, B. Costa, G. Randazzo & A. Zanini 4 Pantano " Arczzi Punta Ciriga rocks exposed and the total and 189oloo in ^^-^,:^- The lagoonal system of sout- heastern Sicily. Superficial samples (111) and cores (52) about 1 m deep were taken in spring 1994. On the basis of both sedimentological and faunal characteristics, and markers containing particular organic componenrs connected with different sedimentary-environmental phases, four layers were identified at the foliowing depths from the surface: -120/-10A, -9A/-8A, -60/-40 and -10lO cm. To establish the evolution of these two lagoons, the lithology of the hydrographic basin, including grain texture and morphoscopy, 'were considered following the models and techniques proposed by Amore &, Randazzo (1996), Amore et al. (1994),Randazzo (1991),Randazzo & Staniey (1,992). In addition, the sandy fraction was analysed for its mineralogicai, faunal and florai composi- tion. Variations of the faunal assemblage were defined in volumetric samples (250 cc) taken from 11 cores reco- vered from the two lagoons. An ecologic horizontal zoîarion of the benthic mollusc assemblages in the different areas was identified (Kinne & Pérès, 1,982).It is controlled by several envi- ronmental factors (nature of the substrate, water mass movement) that depend on sea-water trophic inputs from the pelagic areas. This zonation was compared with the "confinement" theory proposed for paralic en- vironments by Guelorget Er Perthuisot (1983). Pantano Longarini. The study documents the progressive isolation of the lagoons, represented by four easily recognrzable layers (Fig. 3-4). :--J\ (' \ Hanlano Punta Castellazzo 0 500 1000 m i::r__ri-: r: in the hydrographic basins: the pÀ is basic salinity ranges between 7o/oo in December August, strictly related to rainfail and eva- -!l \ \, t- Solid inputs of the hydrographic basin. Longarini and Cuba lagoons Pantano Longarini N ^A LAYER D LAYER LAYER I Pantano Cuba 0 500r: r- 2)1) Layer A is characterized by poorly sorted, fine to very fine sands with finely skewed distributions in the southern sector and by poorly sorted silts in the north- ern sector. Furthermore, in the southern sector a paral- lel or slightly oblique lamination is present, typical of facies originating in lagoonal and back-dune areas. Among the inorganic comPonents, the carbonate grains always represent less than 45olo, while quartz clasts ac- count for more than 50% of the total and are more fre- quent in the eastern sector. This distribution conforms to the eolic nature of the lagoonal edge sediments, as quartz grains are of allocton origin when compared to the rocks of the hydrographic basin (Amore &Randazzo, 1996). Compositional and textural elements present in this layer correspond to the sedimentologic charac- teristics of the lagoonal facies recognized in the Manzala Fig. 3 - Grain-size of sediments and horizontal zonation of faunal assemblages. 1) Grain size di- stributions of sediments: a: substrate; b:well sorted fine and very frne sand: c-poorly sorted very fine sand, with rnud; d:poorly soned silt wirh clry and slndl e:poorly soned clay with silt and sand; 2) Horizontal zonation of f.rrrn.rl .rssemhl.rce: a: subsrra- rei b:Zone III-IV; c:Zone IV; d:Zone IV-V lagoon in Egypt by Randazzo & Stanley (1992) and Randazzo (1992). The sedimentation pattern shows a meteo-marine dominance in the sector most proximal to the sea, indicated by a large amount of well-sorted qlrarrz sands (eolian coastal sands facies). Pooriy sorted silts, rich in carbonates eroded from the hydrographic basin, are prevalent in the most internal sector (silty sands facies of the central lagoon, influenced by rivers). Vithin layer A, the mollusc assemblage is charac- terized by a relative abundance of characteristic species, exclusive to the biocenotic stock of eurythermal and eu- ryhaline lagoons LEE (Pérès, 1967), ranging [rom 77o/o to 83o/o lTables 1-3). The stock of the biocenosis of su- perficial muddy sands in sheltered SVMC areas (Pérès, 1962) constitutes a lower percentage, ranging between 9o/o and 14"/o. The biocoenotic stocks related to the ma- ffi ll 1l ll I ],t1t-tll C. Amore, B. Costa, G. Randazzo G A. Zanini Tab. 1 - Bionomic distributron and abundance of the molluscs species in the volumetnc samples of the Pantano Longarini; biocoenosis nomenclature after Pérès & Picard (1964) and Pérès (1967): LDL:Biocoenosìs of the slowly-drying wracks; LEE:Euryhaline and -"---'L^-*^l L:^;oenosis in brackish waters; SVMC : Biocoenosis of the superficial muddy sands in sheltered areas; SFBC:Bio- coenosis of fine well-soned sands; AP:Biocoenosis of photophilic algae; HP:Biocoenosis of Posidonia meadows; DC:Biocoeno- sis of the muddy detritic bottoms; Lre:species with wide ecological distribution; Sspr.:species without a definite ecological sisnificance. rine environment, such as those of fine well-sorted sands (SFBC), photophilic algae (AP) and Posidonia meadows (HP) are scarce (1olo). It is worth mentioning the presen- ce of a high number of adult specimens of Hydrobia ,uentrosA, a small grazíng gastropod typical of lagoons with vegetation growing on soft bottoms and limited di- rect contact with the sea (Graham, 1988). In contrast, Cerastoderma glaucum is mostly represented by juvenile specimens. This setting, characterized by low diversity and very low equitability is favored by opportunistic species with an r-selected life strategy (Dodd & Stanton, 1981). The presence of marine and stenohaline organisms (sponge spicules, littoral benthic and planktonic forami- nifera, echinoderm fragments and Posidonla leaves) is probably due to occasional storms. Following the model of Guelorget & Perthuisot (1983), this lagoonal assemblage can be related to "confi- nement" zoîe III/IV. -aver A Laver B Laver C Laver D I-IV ITI.TV IV IV SamDles 8A 234 r88 218 238 9B 258 3B 8C 21C 23C 9Cl2sCt3C 18D 21D 23D 9D 25D 3D ,-DL Trun, a t c I I a s ub cy I n d r i ca (Linneo) iiLEE 'ydrob ra ventrosa (Montagu) 4)( 621 3l 529 495 145 l6( 13 35 5 59 126 123 ll l6 '78 59 30 695 159 e r a s Í o d e r ma gl au cum (P oiret) 176 363 469 403 i 355 122 t29 2 126 70 2 35 4 52 '7 23 29 4bra ovata (Philippi) I \4yt i lasf er mar ionl (Locard) ). 4 !MC [,or i p e s I a ct e us (Linneo) 54 t4( '78 138 I 1 4 4 a: er i t h i um v u I go t um ( Bruguièr e) I P ír ene I I a c on i c a (Blainv llle) 2 8 Venerupis aurea (Gmelin) 1 Nas.s ar ius cornrcuias (Olivi) I SFBC enu.s gallina Linneo Donux venustus Poli Ivl icnina umb il rcata lMontasu) ì | y, ymer r v tolor't,st c ns (Lamarck) D ivar r c el I a J rv a r r ru t a (Ltnîeo) 'ellina nitida Poh IP |ornus subcarinatas (Montagu) l{us cu I us c os t ul at us (Rtsso) i i b b ulo t urb ino rcle.r (Deshayes) I P-HP D us tl I na radnla (Philippi) o us il I ina dol ium (Ny st) I ?lsrrru rimrlrs Scacchi 4 ?ìs.roa auriscalpium Linneo I ? tss oa v entr ic osu Desmaf est t l htania lineato Risso iicolía tenuis (Michaud) 'ricolra tpcctosa (von Muhlfeldt) Iu i ub inus str i atus (Linneo) ì mar agd ia v ir i d i s (Linneo) Prtar ruclts (Po\) DC-DE I'imoclea ovqta (Pennant) I Str iarca lactea (Linneo) B itt ium locteum (Philippi) Bìtlium reticulatum (Da Costa) 30 31 48 i0 4 Rhv: o rus u c u m i nalrs (Brusulère) 1lvano cancellalu (Da Costa) unatta sp Totals lro 1 )'t'7 1042 I 009 1042 949 293 t06 ' t88 l5l 155 l'7'7 153 47 156 135 30 7l t8t Fio d Core logs of lithological and faunal characteristics of P. Longarini. T- i LEÉ | l00l I svN,4c | | | .p.mor. | |I cllDr I i ] lrorors lrooj N A fLErTqs!-f lsvMc | 1,8 | | ^ lsp.mor I z,a IlolLDL I I I Ilolols ll00 l trl Longarini and Cuba lagoons f lLEElr.ól lolswc 1 1I 1 sp.mor.l IrltDtll fotoh | 1001 I tLErTtl I D lsvN/c l2,r II I sp.mor | 4,2 l-r ltDL I l [.1"]: Iloql IEE lt;l l- | svMc r,3 I B isp.mo'.1ó,3 i ILDL Ir Jrotors I roo ] I' iiEi---Eól ] SVMC I sp.mdr 1,4 I ILDL i lotols 100 I t. _ I rEE 83,3 | ^ lij*?, ?;î |LDL O,I Ilotols 100 | C. Amore. B. Costa. G. Randazzo & A. Zanini Tab.2 Bionomic distribution and relative abundance (o/o) of the molluscs species found in the volumetric samples of the Pantano Longarini. Layer B is characterized by poorly sorted, fine to very fine sands with fine skewed distributions in the southern and central sectors and by poorly sorted silts in the northern sector. Sedimentary structures are not evident in this layer. Quartz grains, mainly present in the southern sec- tor, reach maximum values higher than 70"/o, whrle car- bonate grains are always less than 30o/o. The more seve- rely skewed distribution of the sands, absence of sedi- mentary structures and dominance of q\Jarfz, together with high percentages of carbonates,suggest a higher de- gree of isolation than underlying layer A. This hypothe- sis is confirmed by the distribution of the faunal assem- blage (Tables 1-3) that shows a further decrease in mo1- lusc abundance in the more southern sector. Marine and "mixed" species (sensu Guelorget 6a Perthuisot, 1983) are much less frequent and the relative abundance of typical LEE species, always more than 82o/o, is increasing. This dominance could be related to zone IV of Guelorget Er Perthuisot (1983). This inter- pretation is fully confirmed by the presence of Ammo- nia beccarii tepida, a typical lagoonal species, and the presence of oogonia of Characeae. It is noteworthy that the marine species are more abundant in the southern than in the northern sector. It is difficult to establish whether the rare speci- mens of the SVMC stock indicate a short episode of colonization or if, more probably, they are the result of p ost-mortem transport. L4Jgr A fll- Iv Layer B Laver C Laver D III-IV IV IV I rv-v IV IV-V SamDles 184 234 t8B I 2tB 238 98 25B 38 lsc 21C 23C 9C 25C 3C l8D 21D 23D 9D 25D 3D LDL 0 ] li lt_ 31.0 293 l9 r 81 3 69 5 ',/2 T run cat e I I a subcy | í nclrì ca (Lineo) LEE 16 6 50 i 43.7 100 96 8 8,1H),)dro b i Lt I e n I ro.\ q (Nlontagu) 588 494 toil m 12.8 4',7 5 '79 r ,,atuJ.nna tlat,, rar lPoiret) Abrd oldta (Philippi) ,19 5 ,10.0 31 A 44.4 41 A 16 8 60.3 6',7 A t1 Ì 9.8 21 12.8 136 52.6 l5 0 85 4.3 01 My I i I a s I e r n a I i o n i (Locar d) 0 0.7 IJ l3 SVNIC 11 s3f rrT 06 0Lo r i pe s I tr c t eus (Limeo) 7.6 q1 t0 l0 8.2 l l.2 1.5 , 7l 06 t: tnthtutn lulldtum ( Bruguière) 1.6 l 0l li) f irenellq conicq (Blainville) 0.2 0 I 0.8 0taarru (Cmelin) 0.t n I 06.Vqlyl,ll ,.,rnl, rrirr lOlivr) II9C Venu,; gullina Litneo 01 0 o a1 0.t a1 a'7 li 53 06Donax renustus Poli t t Ii, nit)a iltnbiIi.,tl.t 1tlonraguI l0 0 0.4 0.3 0 0.1 0t 01 (i I ycym eri.\ t, i o I a c e.rccn.r (Lamarck) 0.t 0.t 0.1 0 ts DiraricelÌLt LII '1'911,,y niiao AP wricata (.Linneo) Poll 0l 'o rnus su h ctt r i n a tu s (Montagu) rlMu s cu / us cos tul ar us (Risso) 0l i i h httl a r u rh i n o i de s (Deshayes) o. 1- AP-HP 21 0o I uttl/ino raJiuta lPhilippil lri l/i nL,L'l iun (\yst) liissoa sirzillr Scacchi Pt.t.raa aurt.t. olf rt,rr I inneo l?i s.t oe I e n I r i ca.\d DesÌnarest q.l a4 0.2 liò'i i004 0l . 0,1 OI I,9t AhttníI lineata Rrsso 0l 0t 9lL r? 0l I t.ù/id ttnui.\ (Michaud) lL 91,! !:: , ,,",, lron \luhfeldr) 1yryllfy: rrrrrtr,.' ll inneo) \ 11 1 1 t, 1.S,li, t r rrl,/ir lLirrneo) DC rinr rutli.i (Poi) 0 0 0t ò' t0 DC-DE finto.l.u ,,t utu (Pennant) re \lrirriu /,ri /eu (Lìnrteo) 0l' rl u.) i: ati 0.1 iil ,.1 lei 07 qri_ r8 òa 0.6 Bí | | ìnn /ac reum (Philippi) 04 Bittinn rctiLul.ttwn (Da Costa) 4.2 5 21 26 [lhyzu n t' u. u, t, i t,a ta. lBrrguier e) \spr. Ah:ania cancellala (Da Costa) 0.1 Luttuttu sD 0l --hrvsolliclq so 0.6 Totals ìOO IOO IOO IOO IOO l0( 100 100 l0o 100 100 l0r ìnn lnl Core logs of lithological and faunal characteristics of P. Cuba. - [rr Tr.lsvMc IB sp,mor,l LDL l Totols ] 100 Longarini and Cuba lagoons o soo -I -- -r - IEE frt]lsvMc I r.7 B lsp,mor.J 5,1 ILDL Ir lTotoh ] 100 I' N A 1000 m níÒ T I LEE 84,ól svMc I i I C sp.morl l I rDL | 15.4 I lrotots lt00l- IEE loot T lwvc lz,z I R sp.mor.J 2ó,2 |-LDLI L lToîols 100 ] IEE l;ta] T lsvMc I I R I sp.mdr 20,5 |- ILDL I Totdts | 100 | 10 C. Amore, B. Costa, G. Randazzo & A. Zanini Tab. 3 - Composition and relative abundance (7") of the molluscs bionomic stocks found in the volumetric samples of the Pantano Longarini layer C is characterized by poorly softed, fine to very fine sands with fine skewed distributions aiong the southern border, by poorly sorted silts in the central sector and by poorly sorted muds with silts and sands in the very northern sector. Rare laminar structures are present. Carbonate grains are uniformiy distributed with percentages of nearly 40olo, while quafiz grains decrease fo 5Oo/o in the southern and fo 30o/o in the northern sec- tors, respectively, demonstrating a trend reversal, swit- ching towards increasing solid input from the basin. The marine mollusc taxa (Tables 1-3) disappear al- most completely and the presence of characteristic ìago- onal species confirms the further reduction of the ex- change of water between the sea and the lagoon. Fora- minifera are more abundant in the central and southern areas and oogonia of Characeae occur everywhere, indi- cating phases of decreased water salinity. In conclusion, this situation is referable to zone fV of Guelorget & Perthuisot (1983) in the southernmost sector and to zones IV-V in the northernmost area. Layer D represents the recent sediments and is characterized, like layer C, by poorly sorted, fine to very fine sands with fine skewed distributions along the southern border, by poorly sorted silts in the central sector and by poorly sorted muds with silts and sands in the very northern sector. Carbonate grains are still present, in percentages decreasing from the northern to the southern sectors. Quartz grains are also present, with increasing percent- ages towards the southern edges. Coastal sediments along the beaches bordering the lagoon on the seaward side are formed by well-sorted fine sands with coarse skewed distributions, completely different from those detected inside the lagoons provi- ding evidence of an exclusively intraparalic lagoonal evo- lution. The frequency ratio between Hydrobia oentrosa and Cerastoderma glaucum shows a direct correlation with the marine inputs: Hydrobia oentrosa is dominant in both the northern and western sectors, while Cerasto- derma glaucum ís dominant in the southernmost area. Consequently, we hypothesize that sporadic communi- cation with the sea occurred in the central-southern sec- tor. This hypothesis is fully confirmed by the presence, in this sector, of sporadic "mixed" species. The central- southern area is referred ro zone IV of the model of Guelorget Ec Perthuisot (1983) and the other sectors are referred to zones IV-V (Tables 1-3). Pantano Cuba. Examination of sediments and fauna revealed three layers lying on a marly substrate cropping out along the banks from bottom to top (Fig. 3-5;Tab. a-6). Layer A is characterized by a marly substraîe crop- ping out along the banks.Thrs indicates that Pantano Cuba likely formed more recently than Pantano Longa- rini. The lagoon sedimentation facies, found in the up- per layers, occurred probably as a result of a periodic flooding by rainfall ol hydrographic network defining the basin. Layer B is characterized by poorly sorted, fine and very fine sands with fine skewed distributions in the central-southern sector, by poorly sorted silts in the central-northern sector and by poorly sorted muds with silts and sands in the very northern sector. Rare iaminar structures are present. Carbonate grains amount to more than 60% in the northern sector with values decreasing to 10-25o/o in the southern sector, while quartz grains present an opposite trend, with per- centages increasing towards the south. The LEE biocenotic stock is dominant. The pre- sence of sporadic specimens of "mixed" and marine spe- Laver A Layer B Laver C Layer D IT IV il.IV IV IV V IV V Samples 184 234 18B 218 238 9B 258 3B 18C 2lc 23C 9C 25C 3C 18D zlD 23D 9D 25D 3D LDL 0.1 LEE 83.5 7',7.4 83.0 92.4 8 i.6 9'7.1 98.6 95.8 96.8 8 5.5 98.8 97.8 100 93.7 85.2 97.0 r00 t00 10t SVMC 9.'7 t4 12.0 1.3 14.3 1.5 1.8 1.0 2.1 '7.3 0.6 2.2 2.1 10.9 1.0 SFBC 0.1 l.J 0.5 0.1 0.'13 0.'7 0.( o. -t 0.6 AP 0.2 0_1 AP-HP 0.6 1,4 0.4 0.3 1.0 t 2.1 0.6 DC I DC-DE 0.t Lre 4.6 5.8 J.J 5.4 îo 0.1 0.'7 1 2.8 0.5 0.6 2.1 L.O Ssor. 0.1 0.2 0.1 0.6 Iotals 100 100 100 100 t00 100 100 100 i00 100 t00 100 100 100 t00 10( 100 100 100 100 Longarini and Cuba lagoons 1,1 Laver B Layer C Layer D III - IV IV-V III-IV fV-V III-IV IV-V Sa 1B 88 I 58 268 288 1C 8C 5C 26C 28C 1D 8D 5D 26D 28D LDL 'runcatella subcylindrica (Linneo) 20 3 Ov ate I la my os o tis (Montagu) EE ventrosa (Montagu) 35 i6 i07 198 55 78 59 344 44 15! tl 65 352 552 C e rast ode rma gl a ucum (Poiret) 51 53 t26 130 104 53 5 t1 10; 102 7 5 10 II 4bra ovaîa (Philippi) SVMC Cerithium 9 li s lacÍeus (Linneo 101 15 aurea (Gmelin conica (Blainvi ) 4 I N as s ar ius c orn i cu lu s (Oliv r) i SF'HN Donax trunculus Linneo SFBC Donax venustus Poli 8 9 Venus gallina (Linneo) 9 12 AP-HP P usill ina r adiata (Philippt) Rissoa similis Scacchi I Ris s oa auriscalpium (Linneo) l Gibbula ardens (von u P seudochama griphyna Linneo DC-C erithiopsis tubercularis ( 1 Lre B ittium re ticulatum (Da Costa) 19: 1 14 Sspr Vitreolina so Iotals l4 130 t12 478 32f 220 13 130 456 548 270 t84 124 453 667 Tab. 4 - Bionomic distrìbution and abundance of the molluscs species in the volumetric samples of the Pantano Cuba; biocoenosis nomencla- ture after Pérès Ec Picard (1964) and Pérès (1967): LDL:Biocoenosis of the slowly-drying wracks; LEE:Euryhaline and eurythermal biocoenosis in brackish waters; SVMC:Biocoenosis of the superficial muddy sands in sheltered areas; SFHN:Biocoenosis of the !:-^ ^--r- i- -'--. shallow waters; SFBC:Biocoenosis of fine well-soned sands; AP:Biocoenosis of photophilic algae; HP:Biocoeno- sis of the Posidonìa meadows; DC:Biocoenosis of the coastal detritic; C:Coralligenous biocoenosis; Lre:species with wide ecoiog. cal distribution; Sspr.:species without a definite ecological significance. cies (zone IIIIIV) may be noted in the whole area, with the exception of the northern sector, which is referred to zones IV-V of Guelorget Ec Perthuisot (1983). There- fore a direct marine interconnection is likely. The occurrence of lagoonal ostracods, benthic fo- raminifera and oogonia of Characeae is rare. The sedimentation facies differs from layer B in Pantano Longarini due to its distance from the sea which favours both the concentration of carbonate grains, and the high relative abundance of brackish wa- ter biocenoses. In conclusion, it is possible to assume that the Cuba lagoon only rarely came into contact with the sea and that flooding, probably only for more or iess limited periods, allowed it to come into contact only with the nearby Longarini lagoon. Layer C is characterized by poorly sorted, fine to very fine sands with fine skewed distributions in the central-southern sector, by poorly sorted silts in the northeastern sector and by poorly sorted muds with silts and sands in the northern belt. Carbonate grains decrease from 60"/o in the northeastern sector to 15o/o in the southwestern sector; quarfz grains have an opposite trend, with increasing values towards the southwestern sector, to a maximum of 650/0. Evidence of an expanding lagoonal environment is provided by the presence of a wider central and northern sector, in which only species characteristic of brackish water euryhaline and eurythermal biocenoses are present. These biocenoses are referabie îo zones IY/Y by Guelorget & Perthuisot (1983), while the fau- na in a small creek in the southern sector is still diversi- fied and referable to zones IIIIN. Layer D represents the recent sediments and is characterízed by poorly sorted, fine to very fine sands vzith fine skewed distributions in the very southern sec- tor and by poorly sorted silts in the remaining part of the lagoon. The northwestern sector is an exception, and is charactenzed by poorly sorted muds with silts and sands. C. Amore, B. Costa, G. Randazzo & A. Zanini Guelorget O. & Perthuisot J.P. (1983) - Le Domaine parali qne. Tiaaaux Labor. Géo\., v. 16, pp. 1-136, Paris. Istat (1988) - Statistiche meteorologiche. Q\, pp. l-244, Roma. Kinne O. & Pérès J.M.(1982) - A Comprehensive, Integrated treatise on Life in Ocean and Coastal Ylater. Marine EcoLogy, v. 5, part t, pp. 642, Ocean management, edi- ted by O. Kinne, John \liley & Sons Ltd, Chichester- New York. Ortolani F. 6c Pagliuca S. (1993) - Climatic variations and cri ses in the anthropized environment in the Mediterra- nean Region. Proc. Geosciences G Arcbeology Seminar, spec. publ. n. 70, pp. llJ-126. Pérès J.M. & Picard I. 0964) - Nouveau Manuel de Bionomie Benthique de la Meditérranée: Rec. Ziav. Stat. Mar. En- doume, v. 31, n. 47, pp. l-137, Marseille. Pérès J.M. (1967) - The Mediterranean benthos: Oceanogr, Mar. Biol. Ann Rezt., v. 5, pp. 449-533, London. Randazzo G. & Stanley D.l. (992) - Sub-recent to modern sediment facies in Matzala lagoon, Nile Delta, F.gypt: natural versus man influenced factors. XXXII Congress and Plenary AssembLy of CIESM, 12-77 Ocrobel Trieste. Randazzo G. (1992) - Evolution of the Nile delta: compari- son between actual and modern sediments of l|/.anzaLa lagoon, vrith Olocenic environments of the deltaic plan (Northern Egypt). Ph. D. Thesis (unpublished), Cata- nia. Received. August 29, 1996; accepted February 27, 1997