Mljet Island Research Articles

Mesaiokeras hurei n. sp. (Copepoda, Calanoida, Mesaiokeratidae) from the Adriatic Sea

A new species of Mesaiokeras is described from the hyperbenthos of Veliko Jezero, a marine lake on the island of Mljet, Croatia. This is the first species of this genus and family (Mesaiokeratidae) reported from the Adriatic and Mediterranean seas. It is characterized by small body length (an average 361 μm for females and 337 μm for males), the low number of free segments (21) and the armature of the antennules, very long spine (a 2 ) of exopodite I of female right leg 4, the presence of long processes on the ventroposterior area of the female genital double-somite, the form and surface ornamentation of the genital area, the form and ornamentation of male and female leg 5, and the form and armature of caudal rami. This species was found in shallow water with very stable hydrographic conditions and at a population density from I to 26 ind. m -3 .

An improved time scale for the Holocene history of vegetation and environment on the South Dalmatian Island of Mljet

An improved time scale for the Holocene history of vegetation and environment on the South Dalmatian Island of Mljet

Mal de Meleda: Genetic Haplotype Analysis and Clinicopathological Findings in Cases Originating from the Island of Mljet (Meleda), Croatia

Background: Mal de Meleda (keratoderma palmoplantaris transgrediens) is an autosomal recessive disorder, first described on the island of Mljet (Meleda), Croatia. The candidate region for the gene responsible for this disorder was found on the chromosome 8qter, and the responsible mutations have recently been identified in 12 Algerian and 7 Croatian families. Objectives: To fully characterize all 12 living cases originating from the original setting of the disease, the island of Mljet, in the light of new findings and using modern diagnostic technology. Patients and Methods: Twelve patients and 37 family members were identified over the period 1998–1999, interviewed and examined. Results: The reconstruction of 8 genealogies suggests a common ancestry of all cases but one. The clinical presentation and pathologic findings of these cases are described in detail and are consistent with previous reports. Symptoms and signs were found to be milder in non-manual workers who had applied continuous symptomatic treatment. Blood samples were taken from 8 cases and 16 close relatives for genetic studies. These confirmed a shared haplotype in all cases, but in none of 17 unaffected control individuals, near the marker D8S1751 on chromosome 8. Conclusions: This review characterizes mal de Meleda in its original setting and shows that the sporadic cases found in the regions of medieval trade routes of the Republic of Dubrovnik (Middle East and Northern Africa) carry the same mutation as the patients from Mljet Island, Croatia.

Ecological characteristics of the Mljet Islands seawater lakes (South Adriatic Sea) with special reference to their resident populations of medusae

Ecological properties and distribution and abundance of medusae were studied over an 18-month period in the Mljet Island seawater lakes, south-east Croatia. Strong stratification during the summer differentiates these lakes from the oligotrophic South Adriatic ecosystem. The lakes are designated as a moderately eutrophicated ecosystem. Very small numbers of hydromedusae were noted, representing only the Anthomedusae and Leptomedusae. A new species of the genus Tima was found in considerable numbers of individuals. High abundance of the scyphomedusa Aurelia sp. was observed throughout the year. This species differs in terms of genetic divergence from Aurelia aurita found elsewhere in the Mediterranean and could be attributed to the boreal origin.

Benthic Foraminiferal Assemblages in a Restricted Environment - An Example from the Mljet Lakes (Adriatic Sea, Croatia)

Benthic foraminiferal assemblages from a peculiar restricted marine environment, the Mljet Lakes (Mljet Island, Adriatic Sea, Croatia) have been studied. These lakes are drowned karst dolines, which are connected with the Adriatic Sea through a narrow, shallow channel. Occasional stagnant conditions in the marine lakes cause hypoxic and anoxic conditions in the bottom waters. Such stressed conditions are reflected in oligospecific benthic foraminiferal assemblages with a Shannon-Wiener species diversity index (H) ranging from 0.8 to 1.0 and equitability index (E) ranging from 0.18 to 0.26, identified in samples from each marine lake. In the more dysoxic Malo Jezero, Haynesina depressula dominates an assemblage of 12 benthic foraminiferal species. In the less (and less frequently) hypoxic Veliko Jezero, we found an Asterigerinata mamilla a s s e m b l a g e with 18 foraminiferal species. A more diverse assemblage containing 55 different benthic foraminiferal species occupies an adjacent opensea station. Long-term salinity measurements indicate that H. depressula tolerates higher salinity than formerly presumed (up to 38 ‰), and is well adapted to stressed hypoxic conditions.

Seismotectonically Active Zones in the Dinarides

Seismotectonically active zones are formed due to displacements of segments of the Adriatic micro-plate that differ in size and in their rate of movement, and by the resistance of the rock masses of the Dinarides. The spatial position of these zones can be determined through the locations of earthquake foci. The zones of seismotectonic activity are then correlated with the most important faults on the surface. The seismotectonically active zones are relatively steeply inclined in the shallowest 10-20 km, which is caused by the oblique contacts between the Adriatic micro-plate and the Dinarides. The zones are curved at depth in many cases, which reflects the compression of the area. Curved parts of the zones are characterised by the greatest pressures and also by the most frequent earthquakes. Mildly inclined zones reflect the reverse displacements in the area, also probably the activity on contacts between rock masses of different density, or the extension of the Adriatic micro-plate subduction. The southern part of the plate is the most active. The greatest pressures caused by these movements occur in the area between Mljet island and Dubrovnik. Therefore the majority of earthquakes, and notably the strongest ones, occur in the area between Split, Imotski, Hvar island and Dubrovnik, as well as along the Montenegro coast in a SE direction.

THE OCCURRENCE OF PARACTAEA MONODI GUINOT, 1969 (DECAPODA, BRACHYURA, XANTHIDAE) IN THE ADRIATIC SEA

The decapod fauna of the Adriatic Sea is relatively well known (Heller, 1863; Pesta, 1918; Stevcic, 1990, 1993). Still, the regions of the area have not all been uniformly investigated. Most studies have focused on the northern part of the Adriatic Sea (Venice, Triest, Rovinj, Rijeka) whereas the decapod fauna in the other parts, with the exception of areas near Ancona, Split, and Kotor, has been relatively poorly studied. The decapods have only been reported occasionally, especially from nearby the offshore islands of Vis (Lissa), Palagruza (Pelagosa), Mljet (Meleda), and Lastovo (Lagosta). Recently, the interest in the Adriatic decapod fauna of the central and southern regions has been increased and several studies have been undertaken. In particular, detailed investigations have been executed by biology students from the University of Zagreb, gathered in a research group named Thais, that acts under the supervision of experienced marine biologists. In the period of 1995 to 1998, Thais members collected biological material mostly by SCUBA diving, at 57 stations on Mljet (Meleda) Island, ranging from the intertidal zone to about 45 m depth. They also visited the islands of Dugi Otok (Isola Lunga) and Kornati (Isole Coronate) on several occasions and sampled quite remarkable collections of decapod Crustacea. During this comprehensive sampling programme a large number of species was sampled, some of which had previously been only rarely reported, often just once or a few times (Belamaric et al., 1995; Kljajo, in prep.). Two were recorded in the Adriatic Sea for the first time as Paromola cuvieri (Risso, 1816) (cf. Belamaric et al., 1995), and Paractaea monodi Guinot, 1969, subject of the present study. The sampling stations are presented in fig. 1. Abbreviations: cw, carapace width (greatest distance at S lobules); cl, carapace length = distance between median part of front and posterior margin of carapace.

New palynological and tephrostratigraphical investigations of two salt lagoons on the island of Mljet, south Dalmatia, Croatia

In the sediments of both of the investigated lakes, the tephra from the Mercato-Ottaviano eruption (Vesuvius, southern Italy) (ca. 7900 B.P.) could be identified. The palynological investigations show that from ca. 9000-7200 B.P. (8000-6000 cal B.C.) deciduous oak forests predominated, with only a few representatives of Mediterranean vegetation. At the transition to the central European Atlantic Period those forests changed to an open vegetation type, dominated byJuniperus andPhillyrea. At about 5500 B.P. (4400 cal B.C.), theJuniperus-Phillyrea vegetation was replaced byQuercus ilex woodland that still occurs on the island of Mljet today and is considered to be the natural vegetation of the Dalmatian coastland. The associated vegetation of theQ. ilex forests changed several times. At the beginning of theQ. ilex period,Juniperus values were still high, but soon they decreased andErica spread. In more recent times theQ. ilex forests were partially replaced by plantations ofPinus halcpensis. Indicators of human impact are sparse throughout the pollen record. Clear evidence for human influence exists only from ca. 3100 B.P. (1300 cal B.C.) whenJuglans andPinus halepensis were introduced to the area. Later,Olea andSecale cultivation can be suggested and further spreading ofJuniperus indicates use of the land as pasture.

Taxonomic Review of Some Barremian and Aptian Calcareous Algae (Dasycladales) from the Dinaric and Adriatic Karst Regions of Croatia

Selected species of the following dasyclad genera, deriving from Barremian and Aptian deposits of the Adriatic and Dinaric karst, areelaborated: Salpingoporella, Acroporella, Actinoporella, Clypena and Praturlonella. A new genus, Piriferella, is established. Descriptions of the following Salpingoporella species are completed with newly established characteristic features and illustrated with appropriate sections: Salpingoporella muehlbergii, S. melitae, S. hispanica, S. hasi, S. urladanasi and S. dinarica. In addition, the following new species are described: S. verrucosa, S. heraldica and S. polygonalis. Apinella jafrezoi, the type species of the genus Apinella, is consideredto be a younger synonym of Salpingoporella hispanica. Actinoporella podolica and Acroporella radoicicae are commented upon. Praturlonella danilovae is illustrated, Selliporella dalmatica and Likanella pejovicae have been transferred to PRaturlonella. Because the problematic Halicoryne nerae has also been transferred to the genusPraturlonella (with it 's inadequate diagnosis and description), a newdiagnosis and more complete description of this species is given.Clypeina? solkani is illustrated by Barremian specimens and Clypeina gigantea n.sp. from the Lower Barremian of Mljet Island is described.Beside the type-species. Piriferella spinosa, the species hitherto labelled Clypeina somalica, or Similiclypeina somalica, has also been transferred to the new genus Piriferella.

Mesozooplankton Sampling Experiments with the 'Adriatic' Sampler: Differences of Catch Between 250 and 125 μm Mesh Netting Gauze

This paper represents data obtained by 'Adriatic' sampler during mesozooplankton sampling experiments carried out at a station in the seawater inlet 'Veliko Jezero' on the island of Mljet. Data on vertical distribution, population density and sampling error between replicate samples collected by the 125 μm mesh net gauze demonstrate that the sampler tested can be efficiently used in quantitative investigations and microdistribution of mesozooplankton in shallow waters.