Further surveys of Pseliodinium vaubanii Sournia (Pirrophyta) in the Adriatic sea

Abstract

The presence, in the North Adriatic sea and in the Chioggia and Marano lagoons, of Pseliodinium vaubanii a rare dinoflagellate species, is reported. Our results showed that Pseliodinium vaubanii is a very frequent and abundant species in these environments.     

Boat-based videographic monitoring of an Adriatic lagoon indicates increase in seagrass cover associated with sediment deposition

Within the scope of a seagrass monitoring program in the Novigrad Sea, Central Croatian Adriatic, we predicted that the annual variability in coverage of seagrasses (Zostera marina, Zostera noltii, and Cymodocea nodosa) can be partially explained by the annual variability in sediment translocation. From 23 fixed DGPS-referenced monitoring video transects followed over three years (June 2007-2009), we calculated annual (i) changes in interior bed seagrass coverage, (ii) gain in seagrass at the lower edge of the bed and seagrass bed expansion, and (iii) accumulation of sediment, its depth dependence, and the associated changes in transect slope. We found that in 2007 to 2008, the year with net sediment accumulation, seagrass coverage increased and the bed expanded. In both years seagrass cover within the seagrass bed increased with increasing sediment accumulation, while seagrass bed expansion was highest under intermediate sedimentation rates. Boat-based videographic monitoring can document both natural sediment movement along the depth gradient, and species-specific responses necessary for informed management of submerged aquatic vegetation in the Adriatic Sea.     

Influence of sugar beet breeding on populations of Beta vulgaris ssp. maritima in Italy

Abstract. It is highly probable that transgenic cultivars of sugar beet may influence wild beets in the seed-production-area of northern Italy. For this reason a survey of the local wild beet populations and their habitat characteristics was conducted in 1994/1995, i.e. before transgenic beets and their off spring could have become established. Wild beets (Beta vulgaris ssp. maritima) were found at 21 locations between Trieste and Cesenatico, as part of the natural littoral vegetation classified as Atriplicetum tatarici (Cakiletea maritimae) and Crithmetum (Crithmo-Staticetea). The analysis of phenotypic attributes leads to a division into three different sub-populations. Greenhouse studies on the morphology and life-cycle attributes demonstrated actual gene flow between conventional seed beet and the examined wild beet population.     

Carbonate facies evolution from the late albian to Middle Cenomanian in Southern Istria (Croatia): influence of synsedimentary tectonics and extensive organic carbonate production

Summary During the Late Albian, Early and Middle Cenomanian in the NW part of the Adriatic Carbonate Platform (presentday Istria) specific depositional systems characterised by frequent lateral and vertical facies variations were established within a formerly homogeneous area, ranging from peritidal and barrier bars to the offshore-transition zone. In southern Istria this period is represented by the following succession: thin-bedded peritidal peloidal and stromatolitic limestones (Upper Albian); well-bedded foreshore to shoreface packstones/grainstones with synsedimentary dliding and slumping (Vraconian-lowermost Cenomanian); shoreface to off-shore storm-generated limestones (Lower Cenomanian); massive off-shore to shoreface carbonate sand bodies (Lower Cenomanian); prograding rudist bioclastic subaqueous dunes (Lower to Middle Cenomanian); rudist biostromes (Lower to Middle Cenomanian), and high-energy rudist and ostreid coquina beds within skeletal wackestones/packstones (Middle Cenomanian). Rapid changes of depositional systems near the Albian/Cenomanian transition in Istria are mainly the result of synsedimentary tectonics and the establishment of extensive rudist colonies producing enormous quantities of bioclastic material rather than the influence of eustatic changes. Tectonism is evidenced by the occurrence of sliding scars, slumps, small-scale synsedimentary faults and conspicuous bathymetric changes in formerly corresponding environments. Consequently, during the Early Cenomanian in the region of southern Istria, a deepening of the sedimentary environments occurred towards the SE, resulting in the establishment of a carbonate ramp system. Deeper parts of the ramp were below fair-weather wave base (FWWB), while the shallower parts were characterised by high-energy environments with extensive rudist colonies, and high organic production leading to the progradation of bioclastic subaqueous dunes. This resulted in numerous shallowing- and coarsening-upwards clinostratified sequences completely infilling formerly deeper environments, and the final re-establishment of the shallow-water environments over the entire area during the Middle Cenomanian.     

Mitochondrial DNA phylogeography reveals the existence of an Evolutionarily Significant Unit of the sand goby Pomatoschistus minutus in the Adriatic (Eastern Mediterranean)

The sand goby Pomatoschistus minutus is a major component of marine shelf and estuarine food webs and an important study organism in behavioural research. Yet, despite the sand goby’s significance, its past and present patterns of migration and gene flow are poorly understood. Here we use the mtDNA control region and parts of the flanking tRNA genes of 63 fish from six localities in the Adriatic (Eastern Mediterranean), Western Mediterranean, Atlantic, and North Sea to investigate the phylogeography of this gobiid. Phylogenetic analyses and population genetics statistics reveal the existence of an Evolutionarily Significant Unit, sensu Moritz (1994), in the Adriatic and another in the Western Mediterranean, Atlantic, and North Sea. A possible biogeographical scenario for the separation of the ancestral population is that sand gobies in the Adriatic and Western Mediterranean split between 10,000 and 5000 years ago when due to the rise in sea temperature they migrated northwards and were bisected by the Italian peninsula. A testable prediction of this scenario is that sand gobies from the Western Mediterranean, Adriatic, and Aegean form three reciprocally monophyletic groups which are the descendants of a three-way diversification event.     

Resources and possibilities for exploitation of North Adriatic seaweeds

Suggestions for a small-scale exploitation of seaweeds in the northern Adriatic are given along with a survey of the fresh weight biomass and chemical composition of individual species. The intertidal is occupied by Fucus virsoides. In polluted sites, it is replaced by seasonal annuals. Cystoseira species are dominant in the upper subtidal and represent the major part of seaweed resources in this area. In polluted sites they are replaced by Halopteris scoparia and Dictyota dichotoma. Peaks in biomass were found in spring in the upper water layers and in early summer lower in the subtidal. The protein content of most species exhibited maxima in spring. Elevated values were found in plants from polluted and estuarine habitats.     

The trophic role of the marine cladoceran Penilia avirostris in the Gulf of Trieste

The herbivory of the marine cladoceran Peniliaavirostris was studied in the Gulf of Trieste(Northern Adriatic) from June 1993 to December1994 using the gut fluorescence method. P. avirostrisoccurred from June to December, butreached its greatest abundance in the summer months.A significant correlation between the gut pigmentcontent and chlorophyll a concentration in thesurface layer was established. Observations with anepifluorescence microscope revealed that the guts werefilled with fluorescing nanoplankton and picoplankton(cyanobacteria). Quantitative estimates indicated thatP. avirostris grazed less than 5% of theavailable chlorophyll a in more than half of allmeasurements, but removed most of the availablechlorophyll a in the surface layer during someperiods in September. It can therefore be concludedthat P. avirostris, together with planktonicprotists, plays an important role within the microbialloop.     

Composition and ecology of the Quercus coccifera L. communities along the eastern Adriatic coast (NE Mediterranean)

The aim of this study is to classify and describe all plant communities with Quercus coccifera covering the entire eastern Adriatic coast and islands from north Croatia to south Albania, and to relate their species composition, chorotypes and life forms to environmental factors using Pignatti ecological indicator values. From total 70 phytosociological relevés, we identified and described four floristically and ecologically distinctive vegetation communities (two new proposed subassociations, one association and stand each) using TWINSPAN and the Braun-Blanquet classification scheme. In Croatia and Montenegro, Q. coccifera is forming macchia within the Fraxino orni–Quercetum cocciferae pistacietosum lentisci. Quercus coccifera occurs only sparsely in south Croatia as a shrubland within Fraxino orni–Quercetum cocciferae nerietosum oleandri subassociation or macchia within the Erico arboreae–Arbutetum unedonis association. Despite the difference in biogeographic position and bioclimates, low shrubby Albanian Q. coccifera stands are more closely related to the Q. coccifera communities from the western Mediterranean. Eastern Adriatic communities appear exclusively within the Querceta ilicis vegetation zone and spread within the meso-Mediterranean belt. They nevertheless are an important part of the region's natural heritage and management plans must ensure that all forms of land are used in a sustainable way.     

Badijella jalzici - a new genus and species of calanoid copepod (Calanoida, Ridgewayiidae) from an anchialine cave on the Croatian Adriatic coast

A new genus and species of calanoid copepod belonging to the family of Ridgewayiidae is described from an anchialine cave on the small island of Badija, Croatia. In the new species Badijella jalzici, body length varies from 720-870 µm in both sexes. The prosome is 6-segmented, the female urosome is 4-segmented and 5-segmented in the male. The antennules are symmetrical and 26-segmented in the female, and 23-segmented on right side in the male, with two areas of geniculation. The caudal rami are symmetrical and longer than wide. The mouthparts and swimming legs 1-4 are identical in both sexes. The female fifth leg is biramous and symmetrical; the male fifth legs are strongly developed, asymmetrical, biramous on both sides, endopods 2-segmented and exopods 2-segmented and complex in structure.