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The association and statistical correlation of anthropogenically important trace metals (TM) Cd, Cu, Pb, Zn and degraded marine microplastic (MP) extracted from the bulk debris samples at two locations from two marine systems, estuarine and coastal, in the Croatian Adriatic coastal area were assessed. The abundance of MP particles at both sites were primarily defined by local wave climate, with the open coastal site containing 9- fold more microplastic particles (>4 mm) as compared to the semi-closed estuarine, or twice as much considering bulk plastics. Generally, the higher abundance of adsorbed metal on MP were observed in the more anthropogenically influenced estuary than in the open coastal site and followed the order: polystyrene > polypropylene > low density polyethylene. The amounts of adsorbed zinc were the highest on all types of plastics at both sites, while the affinity of polystyrene for metals followed: Zn > Pb ≈ Cu > Cd.

The Cetina River Basin (CRB) belongs to a Dinaric karst area (Croatia). According to the obtained results on water and sediment quality, the Cetina River reaches the sixth goal of Sustainable Development (source of drinking water). Together with the CRB water quality assessment, it was confirmed that sediments undoubtedly contribute to the purification of watercourses from trace metals as well as organic matter. In 5 years, water samples were collected at 20 sampling sites and sediment samples were collected at 18 sampling sites. The fresh water of the Cetina River belongs to the hydrocarbonate type due to its lithology. The concentrations of the measured elements in the sediments, normalized to Al, are an indicator of possible pressures affecting the ecosystem of the river. According to the Principal Component Analysis (PCA) for elements in sediments, Principal Component 1 (PC1) describes the geogenic origin of the elements, while Principal Component 2 (PC2) describes positive values reflecting anthropogenic pressures (Total Nitrogen, TN; and Total Phosphorus, TP). Depending on element composition, the factor scores related to PC1 and PC2 resulted in four different groups of sites. The first three groups of sediments showed geological impact, while the fourth group was partially anthropogenic in origin. The hierarchical cluster analysis showed four clusters in relation to the content of the elements. Cluster analysis of all elements and the Total Organic Carbon (TOC) in the sediments showed grouping in only two clusters, the first cluster consisting of Ca, and the second of TOC with other elements.

Removal of Posidonia oceanica banquettes from Sakarun beach (Dugi otok Island, Croatia) was a common practice to increase recreational use during the summer tourist season. The sandy part of the beach showed gradual erosion and has partially disappeared. Geological and geomorphological investigations (including bedrock characterization, analysis of sediment grain size and carbonate content, beach profiling, and digital surface modelling) were conducted over nine-month period to investigate the relationship between the banquette removal and sediment loss. The results indicate that the continuous removal of sediment-laden posidonia banquette may cause a deficit in the beach sediment budget, the effects of which may not become apparent until several-year delay.

The aim of the study was to determine the correlation of metals on floating marine litter and weathered microplastic samples from the pristine area. Sampled were collected from the accumulated material on the natural beach in Mala Stupica Cove (Žirje Island, Croatia) in June 2020. In addition to weathered microplastic, the concentrations of dissolved metals in the seawater, at the same location were determined. According to these measurements, the sampling site can be considered pristine, with Cd and Pb concentrations as background values and Zn and Cu as elements that have no toxic effect, based on the classification proposed by Bakke et al., (2010). The metals of interest due to their high toxicity were Zn, Cd, Pb, and Cu.After sampling, the collected material was sieved through a metal sieve with a 4 mesh size, resulting in 4 subsamples (>4 mm; 4-2 mm; 2-1 mm; 1-0.250 mm). The type of plastic particles from subsample >4 mm was determined by FTIR spectroscopy performed on Bruker Tensor 27 in the region from 400-4000 cm-1. On such defined particles and in the seawater sample, trace metal concentrations were determined by the electrochemical method differential pulse anodic stripping voltammetry (DPASV) with standard addition method by Metrohm Autolab modular potentiostat/galvanostat Autolab PGSTAT204. A static mercury drop electrode (SMDE) was used as the working electrode.Plastic particles were isolated from additional two fractions (2-1 mm and 1-0.250 mm) as bulk samples, but without polystyrene, and the metal concentration was also determined using the same method. Due to the particle size, the type of plastic was not determined. Additional analyzes of metal concentrations on a defined and isolated polystyrene particles (PS) from a subsample (4-2 mm) and (2-1 mm) were also performed.By analogy with sediment particles, one would expect smaller microplastic particles to have higher metal concentrations due to their larger specific surface area, but this was not observed in this study. The metal concentration varied with the type of plastic, and from the observed results, plastics could be ranked according to their affinity for the analyzed metals, as follows: polystyrene (PS)>Polypropylene (PP)>Low-density polyethylene (LDPE). According to an average concentration of all analyzed samples defined as LDPE, Zn could be single out as an element with around 7-time higher affinity for LDPE than other elements (Cd, Pb, and Cu). For samples defined as PP, the highest affinity is observed for Pb, even 30 times higher than in LDPE, followed by Zn and Cu, while Cd has similar values as in LDPE. For PS samples affinity of all elements is higher in comparison with the LDPE and PP, as follows: Pb>Cu> Zn>Cd, with a concentration of Pb 2.5 times higher than in PP and even 88 times higher than in LDPE. A general conclusion could be drawn, but the observed wide ranges indicate the need for additional research to determine the relationship between the degree and type of weathering with the associated metals.This work has been fully supported by Croatian Science Foundation under the project lP-2019-04-5832.

The history of metal pollution in the semi-enclosed and human-influenced marine system of the Boka Kotorska Bay (Southern Adriatic) was studied considering geological composition of the surrounding catchment, the sedimentation rate and the mineralogical and early diagenetic processes in the recent sediments. The determination of background concentrations of metals, undertaken for the first time in this environment, proved to be particularly important for Ni and Cr, which are naturally enriched in the sediments of the southern Adriatic. The results showed widespread moderate contamination with Pb and Sn since the 1970s, while the upper layers of sediments near shipyards, marinas and urban areas were more contaminated with Sn, Cu, Pb, Zn, Cd, As, Sb and Mo. The transport of material through the narrow straits separating different parts of Boka Kotorska Bay resulted in a different geochemical composition of the smaller bays and a limited distribution of contaminated sediments from local sources.

Vrgada Island is situated in the central part of the eastern Adriatic coast. Upper Cretaceous limestones crop out on the surface and Pleistocene sediments cover them in some parts of the island. This study focused on a coastal cliff trending N – S on the northern part of the island. Aeolian-alluvial deposits, which are 12.5 m thick were analysed and three different facies in this succession described. The lowermost facies A highlights a strong aeolian influence marked by an increased silt percentage and was deposited during colder climate conditions. Sand and gravel in facies B were deposited by streams of dense, cold water formed by melting snow and ice from the nearby Dinaric mountains. The bioturbated sandy facies C was probably formed during a warmer climate. An unusually high percentage of augite in the lowermost part of facies A can be explained by the input of volcanic dust, most likely from the Roman or Campanian volcanoes in Italy. This, combined with the surface textures on quartz grains detected from SEM photographs indicates a short distance transport for the sediment, no matter which mechanism was dominant. The sediments from Vrgada Island represent a transitional zone between the north Adriatic islands, where aeolian sediments dominate and the South - Eastern Adriatic archipelago, where mixed alluvial and aeolian sediments were observed.

Cliffs formed in soft rocks are rare coastal forms along the Croatian eastern Adriatic and most exposed to natural erosional processes. The rare example of such cliff affected by anthropogenic activities was developed in marl-dominated flysch in the Split urban zone. Due to the panoramic view cliff-top area is being massively occupied since the 1980ies mostly for the tourism industry and urban development. In spite of increased pressure, little attention has been given to the cliff stability. Ongoing cliff erosion seriously endangers both, coastal infrastructure on the cliff-top, as well as at the narrow shore platform used as a recreational beach area, demanding the urgent development of erosion management plan. In order to do so, fundamental knowledge is needed to understand the cliff erosion driving mechanisms.The non-vegetated cliff face was scanned 11 times by terrestrial laser scanner during the 6-year period (2012-2018). Four representative profiles along the study area were compared on precisely georeferenced point clouds. Additionally, a close examination of the cliff-top, cliff face and shore platform was carried out over 15 times during various seasons and weather conditions in order to recognize erosional processes involved. Cliff retreat rates obtained from our monitoring ranged between 3 and 18 cm/y. Extreme erosion rates of 25-34 cm/y occurred during the 2014/2015 and 2017/2018 monitoring period. Both extremes occurred after autumn and spring high precipitation periods. A causal link between intensive rain periods and erosion was further observed after two landslides during spring 2018. Furthermore, many gullies caused by surface runoff were carved after heavy rains. At the same time, increased amount of groundwater caused seepage along structural discontinuities, inducing surface erosion below the seeping line. All observed erosional processes occasionally lead to the occasional formation of marly talus cones at the cliff toe. Their duration depends on wave climate, and are being gradually removed by waves.Obtained results showed that monitored coastal cliff is predominantly subjected to various processes of surface erosion related with high precipitation, while wave abrasion is of subordinate role. Predominant marl lithology is likely to cause further surface mechanical erosion, highlighting the need for erosion management to be developed.

Surface sediment along the carbonate-bordered eastern Adriatic is highly carbonaceous material, composed largely of biogenic skeletal material. Local outcrops of soft-rock material such as Eocene flysch and Pleistocene sandstones may locally change the composition of the surface sediment cover. Highly erosive coastal cliff developed in Pleistocene sediments on the Vrgada Island gave rise to the idea that local seabed surface sediment may reflect the composition of the cliff sediment. Preliminary results of sedimentological analyses showed that sediment samples collected on both sides of the cliff contain material eroded mostly from the eastern side of the cliff. Subsequent longshore drift caused by dominant waves likely sort fallen material, transporting its finer fractions to the northern side and further into the sea.

Seasonal sampling of the seawater column and sediment in Adriatic coastal areas affected by various anthropogenic activities, primarily aquaculture, was conducted during 2017. In total, 32 samples from two sites (central and southern Adriatic) were analysed by 16S rRNA amplicon sequencing. This approach was selected to test the possibilities of using metabarcoding in studying marine cyanobacteria, exploring their ecology and potential as an indicator group in anthropologically stressed coastal environments. Additionally, physicochemical water column parameters, sediment granulometry and composition were assessed. Water column revealed a seasonal variation of amplicon sequencing variants (ASVs) closely related to Cyanobium PCC-6307, Prochlorococcus MIT9313 and Synechococcus CC9902, as well as seasonal grouping of physico-chemical parameters in PCA analysis. Sediment analysis uncovered greater community richness of 13 cyanobacterial genera and two uncultured groups. The most abundant in sandy gravels and gravelly sand type of sediments were ASVs closely related to Pleurocapsa PCC-7319 and Xenococcus PCC-7305. Furthermore, identified cyanobacterial ASVs predominantly displayed similarity to isolates from tropical areas (e.g. Neolyngbya, Chroococcidiopsis, Trichodesmium, etc.), which could indicate the tropicalization process already ongoing in the fish fauna of the Adriatic Sea.

Terrestrial laser scanning (TLS) in combination with Unmanned Aircraft System (UAS) and modern computer based photogrammetry is currently the best approach for the acquisition of high-resolution 3D spatial information. Highly realistic 3D spatial data sets are becoming the basis for detailed geological studies, providing a multidisciplinary approach in the study and research of both underground and above ground sites. To emphasize the variety of possible implementations of these state-of-the-art methodologies, four characteristic and yet quite different case studies are presented where such geodetic techniques are successfully employed. The presented case studies demonstrate that TLS and UAS photogrammetry, as non-contact surveying methods, are able to reduce survey time and total project costs. As added value, they provide high-resolution data that can be analyzed in a virtual environment from a sedimentological or structural aspect. Stored digital documentation also allows future multi-temporal spatial data comparison at any timeframe and scale, thus enhancing any target geological data gathering and analyses at the studied sites.

Vrgada Island is situated in the central part of the eastern Adriatic coast. Upper Cretaceous limestones crop out on the surface and Pleistocene sediments cover them in some parts of the island. In this study we focus on a coastal cliff elongated in the N – S direction, situated in the northern part of the island. Aeolian-alluvial deposits, which are 12.5 m thick have been analysed. Three different facies in this succession are described. Lowermost facies A has a strong aeolian influence marked by increased silt and clay percentage and was deposited during colder climate conditions. Structureless sand in facies B was deposited from dense, cold water formed by melting snow and ice from the nearby Dinaric mountains. Bioturbated sandy facies C was probably formed during warmer climate. Unusually high percentage of augite in the lowermost part of facies A can be explained by volcanic dust input, most likely from the Roman or Campanian volcanoes in Italy. Combination of surface textures on quartz grains detected from SEM photographs indicate a short transport of sediment, no matter which mechanism) was dominant. Age correlation of possible tephra horizon from Vrgada island with confirmed tephra from Susak Island and dated ice/snow melting period from nearby mountains points to Upper Pleistocene age of sediments, most likely MIS 3 and MIS 2. The sediments from the Vrgada Island represent a transitional zone between the north Adriatic islands, where aeolian sediments dominate and the South - Eastern Adriatic archipelago, where mixed alluvial and aeolian sediments were observed.

Particle size distribution (PSD) is among basic parameters in soil and sediment characterization and provides essential information in sedimentological and environmental studies. The problem with the PSD determination is that for any given sample the result depends not only on the method used but also on the sample pre‐treatment, making them seldom comparable. In this study, the PSD of seven non‐treated and pre‐treated soil samples were determined by four granulometric methods (pipette, sedigraph, particle counter and laser diffraction analysis). Samples were subjected to pre‐treatments commonly used in sample preparation for the PSD determination, i.e., addition of dispersant (sodium metaphosphate) and removal of the organic matter (with hydrogen peroxide). The total organic carbon (TOC) analysis was used to estimate the content of organic matter before and after its removal. The effect of different pre‐treatments was evaluated based on the PSD variations and the changes in the specific surface area (SSA) of the samples. The results highlighted differences in the PSD curves of samples depending on the granulometric method and pre‐ treatment applied. The most pronounced difference was the higher amount of clay fraction determined by settling techniques. The role of hydrogen peroxide in disruption of aggregates was evident in the increase in the SSA as well as the share of fine fraction determined by all four techniques, while sodium metaphosphate made no modifications of the SSA but acted in favour of prolonging settling of clay particles and increasing its content obtained by settling techniques.

This paper proposes a coastal erosion monitoring system for beach erosion management, which we demonstrate on natural and artificial pocket gravel beaches in Croatia. The approach uses low-cost Structure-from-Motion (SfM) photogrammetric imaging and multi-view stereo (MVS) to produce high-resolution 3D beach models for detecting morphological changes and erosion occurrence. Coastal state indicators, such as the shoreline position and subaerial beach volume, are derived from the 3D models and used to quantify changes between surveys. The method is illustrated through two case studies and, to our knowledge, these are the first repetitive measurements taken on the Croatian eastern Adriatic Coast (CEAC). In case of the natural Brsec beach, beach rotation was found to be a response to natural forcing from waves of various incident directions. For the artificial Dugi Rat beach, which loses sediment every winter and is subsequently re-nourished every spring, monitoring showed that beach nourishment is of limited durability. Both case studies showed that the SfM-MVS technique is suitable for the rapid and frequent acquisition of 3D survey data, from which quantitative coastal indicators can be derived to inform future coastal management interventions. Significantly, this low-cost data acquisition has a great potential for regular beach management survey. The introduction of beach monitoring in Croatia is timely because emerging Integrated Coastal Zone Management (ICZM) practices will require data-based approaches. Moreover, rare natural pocket beaches and the ever-increasing number of artificial beaches are extremely vulnerable to natural and man-made changes. Adaptive beach management, based on systematic monitoring data, should be included in the ICZM, and we detail how SfM-MVS-based monitoring can be used at different levels of the ICZM. Implementing robust ICZM monitoring will require broad considerations and consultation with all stakeholders, so we propose that SfM-MVS beach surveys should be initially integrated into the existing monitoring practices for CEAC sea water bathing quality. Extension of the existing database with rapidly-gathered low-cost 3D beach survey data, from a number of targeted beaches, could be used to provide a crucial baseline for the ICZM and strategic coastal monitoring of the CEAC.

This paper is conceived as a contribution to understanding the tectonic setting in the Jabuka region in the Central Adriatic Sea, one of the seismically active regions within the Mediterranean. This seismicity is the result of the compressional tectonics within the Adria microplate, accompanied by halokinetic activity. The Jabuka Islet and the Jabuka Shoal appear to be Triassic igneous bodies extruded by diapir tectonics. Sedimentological, mineralogical and micropaleontological analyses of the surface sediments were done to provide insights into the depositional environment around these igneous outcrops. Coarse-grained gravelly sands surrounding the Jabuka Islet and the Jabuka Shoal are composed predominantly of biogenous detritus, containing small amounts of particles derived from igneous rocks. This highly carbonate sediment cover has been formed in the low-energy environment, below wave base and without terrigenous supply from remote areas. A peculiar finding of reworked Lower Miocene foraminiferal assemblage in the recent surface sediment accompanied with re-interpreted seismic profile was used to propose a conceptual geodynamic model for the Jabuka diapir protrusion. It suggested Miocene age for the earliest protrusion of the Jabuka diapir, followed by further Plio-Quaternary growth and shaping. Together with mostly Paleogene fossil calcareous nannoplankton, fossil foraminifera were presumed to have been weathered from the pierced and extruded overburden rocks and admixed to recent, slowly forming carbonate skeletal association, typical for cool-temperate depositional environments.

The adsorption properties in terms of cation exchange capacity and their relation to the soil and sediment constituents (clay minerals, Fe-, Mn-, and Al-oxyhydroxides, organic matter) were investigated in loess, soil-loess transition zone, and soil at four loess-soil sections in North-Western Croatia. Cation exchange capacity of the bulk samples, the samples after oxalate extraction of Fe, Mn and Al, and after removal of organic matter, as well as of the separated clay fraction, was determined using copper ethylenediamine. Cation exchange capacity (pH∼7) of the bulk samples ranges from 5 to 12 cmolc/kg in soil, from 7 to 15 cmolc/kg in the soil-loess transition zone, and from 12 to 20 cmolc/kg in loess. Generally, CEC values increase with depth. Oxalate extraction of Fe, Mn, and Al, and removal of organic matter cause a CEC decrease of 3–38% and 8–55%, respectively, proving a considerable influence of these constituents to the bulk CEC values. In the separated clay fraction (

Coastal zones are one of the most rapidly changing environments on the global scale, mainly caused by anthropogenic activities (industry, urbanization, tourism and food production). Coastal erosion is primarily a natural process, although human-induced coastal changes are becoming more and more present and are significant factors associated with the loss of beach capacity. The Eastern Adriatic coast (EAC) is one of the most rapidly growing touristic markets within the Mediterranean, along which beaches still represent a leading component of the tourism resource. The objective of this paper is to provide an overview of natural geomorphologic features of the EAC as a starting point for further investigation and sustainable management of the coastal zone. The EAC is generally steep and rocky, mostly built up of karstified carbonates, and characterized, thus, by variety of drowned karstic forms. Beaches in carbonates are mostly small, narrow and scattered pocket gravel beaches. Coasts developed in the flysch and associated rocks are characterized by longer sandy and gravel beaches. The total beach length along the EAC presumably does not exceed 5 % and a small proportion of the beach length in relation to the rest of the EAC emphasizes their value in the touristic valorization, indicating the need for protection and sustainable management. Due to their geomorphologic diversities, fragmentation, different orientation, length, sediment composition and budget, each beach should be studied separately and on a small scale. Detailed information on a beach profiles, the nearshore geomorphology, and the beach processes needed to plan a sustainable coastal development are still mostly missing.

Aeolian-alluvial deposits on the northern part of Vrgada Island were investigated in order to interpret deposition mechanisms and environmental conditions. Preliminary results of basic sedimentological analyses of 49 samples allowed distinguishing 3 facies along the cliff.

Summary The current study explores the possibility that multiple fish farms (FFs) containing sea bass (Dicentrarchus labrax) and sea bream (Sparus aurata) can be successfully integrated within a semi-enclosed bay in the Croatian Adriatic. The research focuses on determining principal environmental factors (EFs) that control the integration and attempts to estimate their individual and synergic ability to influence deposition and removal of organic matter (OM) and trace elements (TE) from the system. The complexity of the designated tasks demanded a comprehensive number of various datasets and samples to be used in the analysis. The ADCP data revealed strong wind induced currents forming within the research domain resulting in high system flushing efficiency (3.5–6 days). The sediment samples from all stations contained relatively inert minerals which contributed to overall low OM and TE concentrations and very limited variability found across the entire bathymetric range. The thermal advection effect recorded at two stations was attributed to specific seabed topography and the hydrodynamic response formed during Maestral wind episodes. The results indicate that a successful integration of four FFs has taken place within the research site (semi enclosed bay), and that the key EFs responsible for its success are strong wind induced hydrodynamics, favorable seabed topography and sediment mineral composition. The synergy of the principal EFs that formed within the system was found to have an attenuating effect regarding FFs chemical influence (OM and TE) and an amplifying one regarding spatial footprint which extended to ≈2000 m distance.

Estuaries are among the most important environments of the coastal zone and are altered to a large percentage by human activities. Thus, their sustainable management, in which sediment and sedimentation processes have a leading role, is becoming a necessity. The present study investigates sediment sources and both natural and anthropogenic factors contributing to the sediment composition in a highly stratified karstic estuary of the Zrmanja River (eastern Adriatic coast, Croatia). This is a small semi-enclosed bay, comprising the riverine part and two other small interconnected bays, the Novigrad Sea and the Karin Sea. The results show that sedimentation in the Zrmanja River estuary is governed by its geological setting (karstic catchment with flysch deposits in the lower part of the estuary), prevailing hydrogeological conditions (influence of the karstic Zrmanja River, the small Karisnica River, and ephemeral streams draining flysch deposits, combined with limited circulation of the basin with open sea), biological production and geomorphology of the basin (general isolation of the basin, especially the Karin Sea). Although the sedimentation processes in the studied area are still primarily determined by natural factors, sediment records also indicate an influence of the hydropower plant in the upper part of the Zrmanja River. A simplified end-member mixing model (EMMA) was proposed to explain possible contributors to the sediment composition in the estuary and their relative mixing proportions. The presented model allows prediction of contribution of different material sources, even at contributions of less than 10%, on the basis of basic and easily measurable parameters (Mz, percentages of sand, silt and clay, and percentages of CaCO 3 and TOC).

Beach nourishment is now widely used as a “soft” coastal protection but its performance is still relatively poorly understood. Beach monitoring allows performance analysis over a range of environmental conditions which, in turn, can provide the basis for successful nourishment design and implementation. Remote sensing techniques based on Structure-from-Motion (SfM) have been successfully used in geomorphological studies in a range of environments, including gravel beaches. This paper presents applications of SfM to two nourished beaches in Croatia. The two different beaches were monitored using different “remote sensing platforms”. First, a larger natural gravel embayed beach was surveyed by unmanned aerial vehicle (UAV). Secondly, an artificial gravel pocket beach was surveyed by using a pole-mounted hand-held camera from the ground. These two cases demonstrated that the SfM method has many advantages in comparison with traditional methods by providing high-resolution 3D data, and being easy to implement and affordable. Hence it has a great potential for regular beach surveys in Croatia to deliver the process understanding required to inform implementations of nourishment schemes.

The terrestrial laser scanner was used for the first-time assessment of erosional rates of the Duilovo flysch cliff situated along the predominantly carbonate Croatian coast, and to characterize processes involved. Cliff retreat rates ranged between 3 and 18 cm/y and stronger erosion occurs during the cold season due to the slaking process. Cliff erosion detected is a combination of flysch weathering, gravitational instability of degraded material and wave erosion. Understanding of cliff erosion processes in the urban zone is needed for the management purposes in the future.

The Republic of Croatia monitors water quality on over 900 official sea bathing areas for the last 9 years. Monitoring is regulated by national and EU directives. This regulation sets out standards for microbiological parameters and other characteristics of the sea. Also, the bathing area profile is determined for each monitored site, containing information about its general characteristics, such as physical properties and bathing area facilities. For the purpose of collecting, validating, managing and public presentation of this data, the Institute of Oceanography and Fisheries developed a web application. This paper presents the extension of the monitoring program and web application in form of additional categories related to beach sediment characteristics. These new elements should provide a base for better coastal management and spatial planning in the future.

In order to contribute to the debate on the role of fluvial erosion in the shaping of karst, two nearby areas with different karstic landscapes were compared. Areas A and B are located relatively close to each other on the southern side of the Krk Island (Adriatic Sea, Croatia). Both areas are composed of similar limestone with a very high CaCO 3 content. Area A is a typical doline or polygonal type (“classical”) of karst with numerous dolines (up to 57/km 2 ) covered with terra rossa (red soil) and Mediterranean maquis shrubland. Dolines are located in zones which correspond to the strike of the main geological structures. Dry karstic valleys are visible only on gently inclined coastal slopes bordering the karstic plateau. In contrast, area B is typical of a bare karst landscape with a strong (palaeo)fluvial imprint. The dolines are absent, and the bedrock is only sporadically covered with terra rossa. Palaeogene marls have been observed in a few elongated depressions and in the coastal zone of area B. Along steep coastal slopes, valleys (up to 460 m/km 2 ) are cut into the carbonates. The traces of episodic surface flows are visible in some of these valleys, in contrast to the valleys in area A. Remnants of a disrupted ancient fluvial network are clearly visible on the elevated karstic plateau in area B. Differences in the recent morphology are attributed mainly to varying thicknesses of the Palaeogene impermeable marly cover, and the intensity of tectonics in the two areas.

The aim of this research was to explore the possibility of a successful and balanced integration of fish farming installations into an ecosystem dominated by Posidonia oceanica (L.) Delile species. We selected light, temperature, seabed topography, sediment characteristics, meadow density, bottom coverage, maximum leaf length and lower depth limit as principle components in assessing the influence of the fish farm. All P. oceanica descriptors showed significant correlation with light deprivation effect while sediment organic matter content revealed slightly higher values than normal, increasing with distance from the cages. The results point to a conclusion that in such lightly nutrient enriched ecosystems, the seagrass growth and distribution are principally controlled by the shadow that cages cast on the seabed below, and that when carefully planned, fish farms do not necessarily degrade the health status of the surrounding area, but in fact facilitate a transition into a secondary stable state.

The choice of analytical method and sample pretreatment has significant consequences for the shape of particle-size distribution (PSD) frequency curves, and therefore for the evaluation of soil textural parameters. Here, the comparison of several granulometric methods based on different physical principles is presented: wet sieving (WS), based on gravity and the mechanical force of water, was combined with pipette (PP) sedimentation/settling velocity, Micromeritics SediGraph (MS) sedimentation/x-ray attenuation and Coulter Counter (CC) electroresistance particle counting. The Malvern Mastersizer (MM), an instrument based on laser diffraction, was used without WS. Twelve typical temperate-region soil types were chosen for this study on the basis of their mineral composition, organic matter content, conductivity and magnetic susceptibility. The modalities of PSD frequency curves obtained by different methods were compared. The results showed considerably larger clay-fraction contents determined with the sedimentation techniques, PP and MS, than that obtained by CC or MM. Statistical correlation and regression models were used to compare the fractions of clay, silt and sand obtained with different methods. Linear correlations were found in almost all cases, except those comparing clay fractions obtained by CC with those obtained by MM, PP and MS methods. These correlations were non-linear. The observed difference was attributed to the presence of aggregates and/or magnetic properties of soil particles. However, more data are needed to verify this hypothesis. The implications of sample pre-treatment with dispersant and hydrogen peroxide (H 2 O 2 ) were evaluated by the MS and CC techniques and observed by the scanning electron microscope. H 2 O 2 was found to be an efficient disaggregating agent. The use of dispersant resulted in the increased amount of the clay fraction measured by the MS method.

The recent shape of the coast in the Kvarner area is primarily a consequence of the drowning of karst relief due to sea-level rise during the Holocene. Further sea-level rise and increased storminess in this coastal area is expected in the future. In order to assess coastal vulnerability, two stretches of the mainland coast and the coast of four main islands in Kvarner have been examined. Most of the coast in the Kvarner area has a low risk of wave-induced marine erosion and has low vulnerability to predicted sea-level changes due to its rocky origin. Carbonate rocky coasts make up most of the coasts, whereas coasts formed in siliciclastic (flysch) rocks are less common. The largest proportion of fine grained beaches (over 20%) is found on Rab Island, due to a higher presence of less resistant flysch rocks. In order to develop mitigation and adaptation plans for future coastal changes, an integrated coastal zone management is proposed.

The intercalation of silty units and coarse-grained units represented by conglomerates and breccia characterizes a Lower Miocene terrestrial sedimentary sequence in the North Croatian Basin, a part of the southwestern Pannonian Basin system. These sediments were previously interpreted as alluvial sediments, where the silty units would reflect deposition on a floodplain. However, in this study, we show new results that support a different interpretation of the genesis of the silty units. The units, which vary in thickness between 6 and 180 cm, are mostly composed of structureless loose silt. They are brownish yellow to yellowish brown in color and do not contain fossils. Scanning electron microscopy indicated that quartz grains show fracture faces, conchoidal fractures, V-shaped percussion marks, linear steps, and conchoidal crushing features. Such microtextures together with the macroscopic characteristics of the silt units indicate that they were deposited by wind. Therefore, this study reports the first occurrence of Miocene loess outside of China. Silt-sized particles were probably produced by salt-weathering processes on salina-type lake flats during long arid periods. Alluvial deposition was controlled by a more humid climate, so the intercalation of eolian silty units with alluvial conglomerates and breccias reflects alternation of arid and more humid periods in the early Miocene. This agrees with regional paleoclimate studies that show cyclicity in the climate, with a dry cycle and orbital-scale climate variability controlling paleoenvironmental and sedimentary changes in the area during the early Miocene.

Glavica (natural) and Dugi Rat (artificial) gravel beaches in Croatia were monitored using ground-based photography and structure-from-motion (SfM) photogrammetry, in order to assess morphological changes after storm events. In contrast to stormy waves caused by Bora winds (NE), Sirocco winds (SE) induced waves which initiated morphological changes on both beaches. Beach orientation with respect to the prevailing wind directions is the governing factor determining direction and quantity of sediment transport. We demonstrate that the SfM approach using Agisoft PhotoScan Pro and high accuracy dGPS measurement can give DEMs with error on control points generally

In the context of current global environmental changes, mapping and monitoring seagrass meadows have become highly important for management and preservation of coastal zone ecosystems. The purpose of this research was to determine the numerical precision of various cost-effective benthic habitat mapping techniques and their suitability for mapping and monitoring of Posidonia oceanica meadows in the Croatian Adriatic. We selected ultra-high resolution aerial imagery, single-beam echo sounder (SBES) seabed classification system from Quester Tangent Co. (QTC), and surface based underwater videography as affordable, non-destructive and simple to use systems for data acquisition. The ultra-high resolution digital imagery was capable of detecting P. oceanica meadows up to 4m depth with 94% accuracy, from 4m to 12.5m depth the accuracy dropped to app. 76%, and from 12.5 to 20 m the system was only capable of distinguishing seabed biota from substrata, though with 97% accuracy. The results of the QTC system showed over 90% detection accuracy for Cymodocea nodosa covered seabed, excellent separation capabilities (>92%) of different sediment types (slightly gravelly sand, gravelly muddy sand and slightly gravelly muddy sand) and reasonable accuracy for mapping underwater vegetation regardless of the bathymetric span. The system proved incapable of separating P. oceanica from dense macroalgae on the same type of substratum. Surface-based underwater videography demonstrated great potential for estimating P. oceanica cover in a sampled region using either a single human rater or a computer estimate. The consistency between two human scorers in evaluating P. oceanica bottom coverage was near perfect (>98%) and high between digital and human scorers (80%). The results indicate that although the selected systems are suitable for mapping seagrasses, they all display limitations in either detection accuracy or spatial coverage, which leads to a conclusion that suitable system integration is essential for producing high quality seagrass spatial distribution maps.

Granulometric, mineralogical and morphological investigation of the sea-bottom sediments in the Grgur Channel has revealed fi ve sediment types, the most frequent of which are muds containing some amount of coarse fractions (sand and gravel). The coarsest fractions are predominantly composed of recent shell fragments. Unexpected well rounded carbonate gravel was found SE of Prvić Island in 83 m of water. This gravel was presumably transported, shaped and deposited during a sea-level lowstand, by stream and/or in a beach environment. Fine-grained fractions have a siliciclastic composition and suggest a predominant terrigenous origin. One part of the fi ne-grained fraction originates from the recent subaerial weathering of fl ysch outcrops, and the other from previously active (during a lower sealevel), subaerial erosion of presently submerged fl ysch outcrops. As a result of the rapid Late Pleistocene– Holocene transgression, the investigated sediments are now below the present wave-base. Due to a presumed very low or even negligible rate of recent sedimentation in the study area, older sediments in the Grgur Channel remain uncovered and bioturbated by burrowing organisms. Therefore, analyzed surface sediments from the Grgur Channel are considered as a mixture of recent and subrecent deposits. From this investigation, a new seabed sediments map of the Grgur Channel was produced, as an improvement on the existing sedimentological map of the Kvarner area.

Gljiva Cryphonectria parasitica uzročnik je raka kore pitomog kestena. U ovaj patosustav uključen je i virus (Cryphonectria hypovirus 1, CHV1) čija prisutnost smanjuje virulentnost gljive, fertilitet (smanjuje sporulaciju) i brzinu rasta micelija, stoga se ovaj fenomen naziva hipovirulentnost. U tom slučaju, zaraženo stablo može stvoriti kalus oko lezije, te tako ublažiti progresiju bolesti. Prijenos virusa je moguć spajanjem (anastomozom) hifa gljiva i nespolnim sporama (konidijama). Jedan od ograničavajućih faktora horizontalnog prijenosa CHV1 je sustav vegetativne (ne)kompatibilnosti [1]. Na području Ozlja i Kašta zastupljenost hipovirulentnih rakova se povećala u odnosu na prethodna istraživanja. U Ozlju se vrijednosti kreću od 44, 1 % u 2008., 38, 5 % u 2014. te 47, 2 % u 2019. dok je u Kaštu vrlo slična situacija (33, 3 % u 2014. i 40, 7 % u 2019.). Za razliku od 2008., kada je u Ozlju nađeno samo 5 EU-tipova, 2014. i 2019. nađena je veća raznolikost EU-tipova (14, odnosno 9). U Kaštu je 2014. nađeno 8 a 2019. 11 različitih EU-tipova[2]. Cryphonectria hypovirus 1 se za sada ravnomjerno širi kroz populaciju tj., nalazimo ga u više različitih EU-tipova. Uočena promjena u raznolikosti populacija između Ozlja uzorkovanog 2008. i Kašta uzorkovanog 2019. nam ukazuje da iako je riječ o geografski bliskim populacijama (zračna udaljenost ≈12km) u posljednjih 10-tak godina ipak je došlo do određenih promjena u njihovom sastavu (brojnosti i raznolikosti EU-tipova). U Ozlju se tijekom vremena raznolikost populacije nije značajno promijenila s iznimkom 2014. godine kad je nađen veći broj EU-tipova. Obzirom na raznolikost EU-tipova populacija u Ozlju i Kaštu je vrlo velika (slična zemljama u kojima je ova bolest prisutna od sredine 20. stoljeća). Zastupljenost hipovirulentnih rakova se povećala te je CHV1 pronađen u većini EU- tipova prisutnih u istraživanim populacijama, što znači da se virus uspješno prenosi u populaciji.