ANNALES 13/'98 original scientific paper UD C 582.263(262.3) ULVA SCANDINAVICA SLIDING, (CHLOROPHYTA): A NEW SPECIES FOR THE ADRIATIC SEA Claudio BATTELU A. Sema Secondary School, 51-6320 Portorož, Med vrtovi 8 and Faculty of Education Ljubljana - Department of Koper, Sl-6000 Koper, Cankarjeva 5 lan H. TAN Royal Botanic Garden Edinburgh, Edinburgh LH3 SLR, Scotland, UK, 20A inverleith Row ABSTRACT This article deals with the very first report on the occurrence of UIva scandinavica Biiding, in the Adriatic Sea. A genera! description of this species is given, as well as its basic morphological and anatomical features its manner of reproduction, its geographical distribution and its habitats in the coastal waters of Slovenia. Key words: Ulva scandinavica, genus Ulva, Chlorophyta, occurrence, Adriatic Sea INTRODUCTIO N In September 1998, the green aiga Ulva scandi­navica Biiding was recorded for the very first time in the coastal waters of Slovenia (Gulf of Trieste). The genus Ulva (Linnaeus) Thuret belongs, together with the genera Capsosiphon Gobi and Enteromorpha Link, to the family Ulvaceae Lamour. ex Dumort (Gal­iardo eta!., 1993). Ulva thalli are wide, flat, lobed, of grass green col-our, and composed of two adhered layers of parenchy­mal cells. Ulva is also commonly known as "sea lettuce?' world wide. They occur, attached to the substratum, mainly in the lower midlittoral and in the upper infralit­toral; they may also occur as epiphytes on other algae, or unattached (benthopleustophitically) in the upper in­fraiittoral to a depth of about 3 metres (Rizzt-Longo & Giaccone, 1974; Vukovic, 1980, 1984a, b). In protected areas (particularly bays) and polluted waters {e.g. ports) their thalli can grow up to 1 m in lenght, while in more exposed and cleaner waters they are usually smaller. The most characteristic feature of Ulva species is that their development begins with a single-serial threadlike thallus. The thallus then becomes multi-serial and eventually grows into hollow cylinder (tubelike). The walls of a young (a few millimetres long thallus) grow closely together resulting in a flat 2-layered thick thallus. The cells have only one nucleus and one hood-like pa­rietal chloropiast with one or more pyrenoids. In the rhi­zoidal part of the thallus the cells are multinucleate. Asexually, they reproduce with zoospores; sexually, they reproduce with sexual cells (gametes). Vegetative frag­mentation also occurs and results in freeliving individu­als. Their life cycle is mostly diplohaplontic (digenetic) and isomorphic. Diploid sporophyte is formed from a zygote, and sporangia are developed from vegetative cells. After reductive division, zoospores with four fla­gelia are produced. From these zoospores, haploid gametophytes develop. On the margins of the gameto­phytic thallus, gametes are formed. These gametes are smaller than the zoospores, and they are equipped with two flagella. Male gametes are smaller than females ones. Reproduction can be also parthenogenetic, where the gametes can develop directly into haploid thalli. All the vegetative cells, except the basal ones, can trans­form into reproductive cells. They are attached to the substratum with a small fastening holdfast. This holdfast is perennial and produces a new thallus each spring. Ulva is found ail over the world from arctic to tropical regions, including the Adriatic, Mediterranean and Black Seas, the Atlantic, Indian and Pacific ocean (Biiding, 1968; Van den Hoek etal., 1995). 121 ANNALES 13/'98 Claudio BATTEUÍ, ten H. TAN: ULVA SCANDINAVICA BUDING, (CHLOROPHyTAJ: A NEW 5PECIE5 FOR THE ADRIATIC SEA, 125-124 Fig. 1: Study area with sampling stations. SI. 1: Obravnavano območje z vzorčevalnima posta­jama. COLLECTIO N AN D OBSERVATION Samples were collected from the coastal waters of Slovenia (Semedela and St. Simon Bays) in the lower midlittoral and in the upper infralittoral to a depth of about 3 metres (Fig. 1). Samples were kept as dry as herbarium specimens and chemically treated as wet preparations in 3-5% methanal (formalin) solution in seawater. The alga was identified according to the criteria by Sliding (1968) and Rizzi-Longo & Giaccone (1974). These criteria include 1) the thickness of the different parts of the thailus (particularly the margins in the upper part of the thailus and the basal part immediately above the rhizoid), 2) arrangement of the ceils on the surface, 3) jagged protuberances on the margins, 4) size and shape of the cells, and 5) number of pyrenoids in the chloroplast. The collected samples were further con­firmed as U. scandinavica by comparisons of their DNA sequences (nuclear ribosomal internal transcribed spac­ers) with those of other Ulva spp. from all over the world. DESCRIPTION OF THE SPECIES Ulva scandinavica (Lat. Ulva, sedge; scandinavica, Scandinavian) was first described as a new species in 1968 by Bliding. It had been collected already in 1959 in Sweden and in 1962 in Norway. Its thailus is flat and lobed. Its size normally varies from 10 to 30 cm and is either dark or light green. The upper part of the thailus is about 50 pm thick, its middle part is about 70 pm, and its basal part is about 100 pm. its margin has a number of jagged protuberances which, however, are not branched out as in the related species U. rígida (Fig. 2). The cells are, in most cases, distributed irregularly. It is character­istic for this species that areas with regularly arranged cells alternate with small areas with cells arranged in rows (Fig. 3a). As far as their cell shape is concerned, they are either polygonal or spherical. The cells contain one chloroplast each along the wall. The number of py­renoids per cell normally varies from 3 to 6 (Fig. 3b). There is no metagenesis in this species. The algae re­produce with biflagellated zoospores (Bliding, 1968). DISCUSSION AN D CONCLUSION S According to Gallardo etal. (1993), 10 species of Ul­va occur in the Mediterranean Sea. Of these, 5 occur in the Adriatic, i.e. U. cúrvala (Kützing) De Toni; U. fas­ciata Delile; U. oiivascens Dangeard, 1961; U. rígida C. Agardh, 1822, and U. rotundala Bliding, 1968 (Giac­cone, 1978; Gallardo et a!., 1993; Span & Antolic, 1994; Span etal., 1996). Fig. 2: Toothlike protuberance on the thailus margin (Photo: M. Richter). Si 2: Nazobčan izrastek na robu steljke (Foto: M. Richter). 122 ANNALES 13/*98 Claudio BATTF.LU, lan H. TAN: ULVA SCANDINAVICA BUDIN'G, (CHIOROPHYTAÎ: A NEW SPECIES FOR THE ADRSATIC SEA, 121-124 _ < 3b 20 pm Fig. 3; Celi arrangement (a) and the chloropiast struc­ture with pyrenoids (b). Si 3: Razporeditev celic na površini steljke (a) in struk­tura kloroplastov s pirenoidi (b). As far as the Mediterranean Sea is concerned, U. scandinavica was recorded only on the west and south coast of Italy (Cormaci ef ai., 1985; Giaccone et ai, 1985; Cecere, 1990; Cecere et a!., 1991a, b). Prior to 1998 there have been no data on its occurrence in the Adriatic. Among the Slovene scientists who have dealt with the algal flora of our coastal waters and prepared its checklist are: MatjaSic & Stirn (1975), Vukovic (1980, 1981, 1982, 1984a, b), Bussani & Vukovic (1987) and Munda (1992, 1993). According to them the species U. rigida occurs as the only representative of the genus Vi­va in the Slovenian coastal sea. Faganeii et at. (1986) have on the basis of carbon (§13C) and hydrogen (8D) isotope measurements in Uiva rigida reached a conclu­sion that two groups exist in our sea, i.e Uiva A and Ui­va B. However, there is no mention in their work about which particular species from the genus Uiva constitute these two groups. The Italian algologist Giaccone thinks {pers. comm.) that the occurrence of U. scandinavica in the Adriatic Sea is probably the result of "meridionalisation", i.e. shift of many algal species from the southern part of the Mediterranean Sea towards the north, in this case the Adriatic Sea. ACKNOWLEDGEMENTS Our cordial thanks to Prof. Dr Giuseppe Giaccone of the Catania University (Italy) for his kind help in provid­ing data on the occurrence of U. scandinavica along the Italian coast. We are also indebted to Dr A. Vukovif from the Marine Biological Station Piran for his assis­tance in the collection of suitable literature and for his precious information on the algal flora of the Slovene coastal waters. And finally we wish to express special thanks to Marjan Richter for his photographic material. ULVA SCANDINAVICA B L I DING , (CHLOROPHYTA) : NOV A VRST A V JADRANSKE M MORJ U Claudio BATTELLi Gimnazija A. Sema, SI-G320 Portorož, Med vrtovi 8 in Pedagoška Fakulteta Univerze v Ljubljani, - enota Koper, $1-6000 Koper, Cankarjeva 5 lan Fl TAN Royal Botanic Garde n Edinburgh, Edinburgh EH3 SLR, Scotland, UK, 20A Inverleifh Row POVZETEK V članku obravnavava pojavljanje nove vrste za Jadransko morje iz rodu LJlva (Linnaeus) Thuret, to je Uiva scandinavica Biiding. Vzorce sva nabrala v spodnjem mediolitoralu in v zgornjem infralitoralu v slovenskem obal­nem morju (Semedelski in Simonov zaiiv). Shranjeni so kot mokri preparati v 4-5% metanalu (formalinu) in kot suhi 123 ANNALES 13/'98 Clnjfio BATTHU.I. I.t:t M. I t.-: vm .V< A.xij;\AV:<.A Ki !i>!N;<. (CHLOROPHVTA): A NEVV SPEC1ES FOR THE AORlATtC SEA, 121-124 preparati v lastnem algariju. V delu podajava splošne morfološke, razmnoževalne in ekološke značilnosti rodu Ulva in podroben opis vrste U. scandinavica. Obravnavava predvsem tiste morfološke znake, ki so osnova za določanje. Ti znaki so naslednji: premer bazalnega dela, razporeditev celic na površini steljke, število pirenoidov v kloroplastib ter oblika izrastkov na robu steljke. Opis je obogaten z risbami. Risbe so shematične; njihov namen je predstaviti osnovne posebnosti, s katerimi lažje prepoznamo obravnavano vrsto. Ključne besede: Ulva scandinavica, rod Ulva, Chlorophyta, pojavljanje, jadransko morje REFERENCES Bliding, C. 1968. A critical survey of European taxa in Ulvales II: Ulva, Ulvaria, Monostroma, Kornmannia. Bot. Not., 121: 535-629. Cecere, E. 1990. Economically important seaweeds in Mar Piccolo, Taranto (Southern Italy): a survey. 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