1,721,004 research outputs found
A PRELIMINARY PLAN FOR THE STUDY OF THE ZOOPLANKTON IN THE GULF OF VLORE (ALBANIA)
No full textA preliminary survey on the zooplankton composition and distribution has been carried out in the Gulf of Vlore to standardise methods. Micro- and Meso-zooplankton were collected from 7 stations with different mesh sized nets, on 7 June 2003. A total of 94 categories were recognised (34 at the species level). Differences between the 6 Gulf stations were less significant than those resulting from the comparison of each of them with the single station of the Otranto Channel. The presence of fish larvae and eggs was recorded, together with the larval stages of Stomatopoda. This allowed us to affirm the importance of the inlet as nursery areas for fishery important species. The degree of confinement of the area was indicated by the indicator species belonging to the copepod family of Acartiidae (Calanoida), and Oithonidae (Cyclopoida), and by the different size of copepods belonging to different populations of the same species. A plan for future investigation has been proposed to monitor the presence (either in space and time) of economically important larvae and juveniles, to understand life cycle timing of their species in the Gulf of Vlore
ACTIVE AND RESTING STAGES OF ZOOPLANKTON AND ITS SEASONAL EVOLUTION IN A HYPERSALINE TEMPORARY POND OF THE MEDITERRANEAN COAST (THE “VECCHIA SALINA”, TORRE COLIMENA, SE ITALY).
Full text linkThe species composition of the zooplankton and its variability were studied in an integrated water-sediment analysis for a period of two years in a hypersaline temporary pond in the SE Italy. The zooplankton showed the presence of seasonal species (mainly Anostraca), together with not seasonal but opportunistic ones (mainly Rotifera, and Ciliophora) with a shorter life-cycle. Rotifers, and Ciliates attained 99-100 % of total plankton organisms in certain periods. Resting stages were extracted from the upper 6 cm of 14 sediment cores collected during a dry period (August 1998). A total of 24 resting morphotypes (cysts) were listed: more than double the number of active organisms (11) found in the plankton over the two years studied. The seasonal succession of species was different in the two years. This fact, together with the richness of the cyst bank in the sediments, indicates that in each period the water column shows only a portion of the biodiversity which the sediment contains unexpressed as resting stages. The study of cyst distribution (both horizontal and vertical in sediments) provided complementary suggestions to understand the space-time distribution of the plankton organisms. Laboratorary tests showed that hatching of different cysts generally occurred in a wide range of salinity conditions, and it was not synchronous. This allowed us to assume that even the cyst hatching rate could be an adaptation to highly variable extreme environments
THE PLANKTON OF A SHALLOW SUB-MARINE CAVE ("GROTTA DI CIOLO", SALENTO PENINSULA, S-E ITALY)
Full text linkComposition and abundance patterns are described for the plankton assemblages in a shallow submarine cave on the Salento peninsula side of the Otranto Channel (SE Italy). A total of 232 taxa were recognized. The cave plankton appeared more affected by huperbenthos than the outside plankton. Mysidacea represented the most conspicuous component of the cave plankton , with two species typical of Salento caves. Harpacticoida, together with asexual algal propagules, dominated the plankton of the cave numerically, whereas Calanoida and Cyclopoida along with mollusc veligers, characterized the plankton in the outside sector. While the mysid Siriella jaltensis was found outside the cave in nocturnal samples, Hemimysis margalefi appeared to migrate simply along the axis of the cave, never leaving it during night. The community composition changed seasonally over the 1-year period. Therte was a clear horizontal partitioning of the plankton, with significant differences between the two stations inside the cave. Higher water turbulence probably explains the presence of asexual propagules even at the inner station. An explanation of the benthos impoverishment has been proposed as an alternative to the current “trophic depletion” theory
The co-occurrence of Artemia parthenogenetica and Branchinella spinosa (Branchiopoda: Anostraca) in a saline pond of south eastern Italy
No full textNew records of the australasian copepod Boeckella triarticulata (Copepoda, Calanoida, Centropagidae) in Italy.
No full textOccurrence and distribution pattern of Palaemon spp.shrimps in a shallow submarine cave environment: a studycase in South-eastern Italy
No full textThe common shrimps of the genus Palaemon are often reported as living in
Mediterranean submarine caves. The present study quantifies the distribution
pattern of a Palaemon spp. populations throughout 1 year of observations in a
shallow submarine cave in South-eastern Italy, Ionian Sea. The cave was subdivided
into six sectors from the entrance towards the inner portion of the ‘blind
cave’ and 16 dives (four per season, during both day and night) were performed
with SCUBA equipment. The population was estimated in situ using
visual census. Four different species of Palaemon were identified. This study
has shown that Palaemon spp. assemblages live throughout the year in submarine
caves. Moreover, the results suggest submarine caves play an important role
in the biology of Palaemon spp. populations, by providing refuge, juvenile
recruitment and food resources
Egg banks in hypersaline lakes of the South-East Europe
No full textThe cyst banks of 6 coastal hypersaline lakes of South-East Europe have been investigated. The
study concerned the bottom sediments of Khersonesskoe and Koyashskoe lakes in the Crimea
(Ukraine), Nartë saltworks (Albania), Vecchia Salina at Torre Colimena (Apulia, Italy), Pantano
Grande and Pantano Roveto at Vendicari (Sicily, Italy). A total of 19 cyst types were recognised.
The cyst banks of lakes were found to be well separated in the representation derived from a
statistical multivariate data analysis. For all the lakes examined a comparison was possible between
the resting community in sediments (cyst bank) and the active one in the water. The cyst banks
contained more species than those recorded over a multi-year sampling effort in the water column.
The study of cyst hatching, performed on 5 cyst types under lab conditions, demonstrated that
cysts do not hatch under the same conditions. Furthermore, each cyst type shows a wide range of
preferential hatching conditions, which allow us to confirm the ecological generalism of salt lake
species
PLANKTON RESTING STAGES IN THE MARINE SEDIMENTS OF THE BAY OF VLORE (ALBANIA)
No full textIn the frame of the INTERREG III CISM project, sediment cores were collected at 2 stations in the Gulf of Vlor ̈e to study the
plankton resting stage assemblages.Atotal of 87morphotypeswere identified and produced by Dinophyta, Ciliophora, Rotifera, and
Crustacea. In 22 cases, the cyst belonged to a species absent fromthe plankton of the same period.Themost abundant resting stages
were those produced by Scrippsiella species (Dinophyta). Some calcareous cysts were identified as fossil species associated with
Pleistocene to Pliocene sediment, although they were also found in surface sediments and some of them successfully germinated,
thus proving their modern status. Total abundance generally decreased with sediment depth at station 40, while station 45 showed
distinct maxima at 3 and 8 cm below the sediment surface.The depth of peak abundance in the sediment varied with species.This
paper presents the first study of the plankton resting stages in the Bay of Vlor ̈e. The study confirmed the utility of this type of
investigation for a more correct evaluation of species diversity. In addition, the varying distribution with sediment depth suggests that this field could be of some importance in determining the history of species assemblages
LE GROTTE SOMMERSE DELLA PENISOLA DEL KARABURUN (ALBANIA): PRIMI DATI
No full textNegli anni 2003, 2004, e 2005, sono state organizzate 3 spedizioni finalizzate alla esplorazione subacquea degli ambienti costieri dell’Albania Meridionale. Durante la prima spedizione, all’estremità della penisola del Karaburun, sono state rinvenute ed esplorate 4 cavità sommerse il cui rilievo speditivo e la descrizione sommaria dei popolamenti rinvenuti sono stati qui riportati per la prima volta. Nel corso della seconda e della terza spedizione si sono perfezionate le misurazioni e le descrizioni delle caratteristiche biologiche della parte sommersa della grande grotta di Haxhi Ali
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