1,721,433 research outputs found
Coexistence of Ulva rigida C. Agardh and Ulva laetevirens Areschoug (Ulvales, Chlorophyta) in Venice Lagoon and other Italian transitional and marine environments.
No full textThere is confusion about the identity of laminar Ulva thalli in Italian and Mediterranean transitional systems and on the open coasts. Although some authors report the presence of both U. rigida and U. laetevirens, systematic revisions for the Adriatic and Mediterranean Seas recognise only the presence of U. laetevirens. This paper uses anatomical and environmental analyses to provide evidence for the presence of both species. The only diagnostic character that distinguishes the two is cell shape in cross section of rhizoidal and basal regions. Therefore, identification of floating thalli in these regions is not possible. The species grow and coexist in the same environments and on the same substrata, but analysis of environmental data suggests that U. rigida occurs preferentially in eutrophic environments, especially lagoon areas rich in phosphate, ammonium and phytoplankton, whereas U. laetevirens is more abundant in areas where nutrient levels are low. © 2010 by Walter de Gruyter Berlin New York
Distribuzione, biomassa e produzione di macroalghe e fanerogame marine in laguna di Venezia (estate 2003)
No full textAtlante fotografico e chiavi tassonomiche delle Chlorophyta multicellulari e delle fanerogame acquatiche; ambienti di transizione italiani e litorali adiacenti.
No full textAttuazione del "Piano per la gestione delle risorse alieutiche Delle lagune della Provincia di Venezia". Analisi ed elaborazione di dati ambientali raccolti nell’ambito di incarichi assegnati dalla Provincia di Venezia al dr. Giuseppe Pessa e loro integrazione con dati raccolti in programmi svolti dal Dipartimento di Scienze Ambientali
No full textRapporto Final
Flora and vertical distribution of macroalgae in the lagoon of Venice: a comparison with previous studies
No full textDuring the years from 1979 to 1984, macroalgal samples were taken every month in 15 stations, representative of the Venice littoral, in order to determine the species and the vertical distribution of phytobenthic associations. A great difference has been found with the results of previous papers (Sciiiffner & Vatova, 1938; Pignatti, 1962), due to the eutrophication increase. Many oligo- trophic species, such as those belonging to the «Cystoseira association» have disappeared, whereas some genera, once very abundant, are presently strongly reduced, for instance Laurencia, Polysiphonia and Dasya. On the contrary many Ulvaceae have colonized all the studied area thanks to their adaptation to pollution. The percentage of Chlorophyceae has increased considerably, ranging from 20 to 3496, whereas Rhodophyceae decreased from 65 to 51%. Phaeophyceae percentage remained pratically unchanged ranging from 13 to 15%. Zostera marina, Zostera noltii and Cymodocea nodosa, once spread in all the lagoon, now only grow far from the urban wastes of Venice and the industrial effluents of Porto Marghera. The limits of the deepest vegetational zones and the vertical distribution of their characteristic populations has also changed and many macroalgal species presently characterize higher level waters
Verifica di qualità ambientale nelle aree a pesca tradizionale e migliorativa; prosecuzione delle proprie attività di controllo dell’evoluzione sedimentologica e chimica dei fondali; documentazione delle conoscenze esistenti sulla biologia di T. philippinarum e sui rapporti tra detta specie e le variazioni biocenotiche dei fondali; definizione delle zone omogenee e delle unità confinate
No full textICRAM, Rapporto Final
Coesistenza di Gracilaria gracilis (Stackhouse) Steentoft et al., Gracilaria longa Gargiulo et al. e Gracilariopsis longissima (S. G. Gmelin) Steentoft et al. in alcuni ambienti di transizione italiani
No full textRuppia maritima L. e Ruppia cirrhosa (Petagna) Grande (Helobiae, Spermatophyta) in laguna di Venezia.
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