Promjene fizikalno-kemijskih karakteristika holocenskih sedimenata iz srednjeg dijela Jadrana (Hrvatska)

Grain size, organic matter and carbonate content were analyzed in 5 Holocene sediment cores from the middle Adriatic. Fine-grained, non-carbonate particles settling prevailed in the investigated area. The differences among the stations were influenced by location and hydrodynamic conditions at the sampling sites, by the weathering of the surrounding areas partly under anthropogenic influ¬ence and the presence of the remains of the organisms with carbonate skeleton. Even though the east Adriatic coast is mostly carbonate, at the stations near the east Adriatic coast, the presence of the Eocene flysch deposits results in the lower carbonate content (40.27-48.88%) in the sedi¬ment with the predomination of silt-sized particles (33.12-56.83%). At the station near Vis Island the sediment is mostly carbonate (67.36-76.5%), with the highest sand content (67.07-70.63%). The source of this sediment are the skeletal remains of the organisms which lived on the seabed, the pre-Holocene sediments and the carbonate rocks from surrounding islands. At the deepest station located closer to the west Adriatic coast clayey particles prevail (52-70%), while carbonate content is low (31.7-40.5%). These clayey particles are the result of the erosion in the Alps and the Apen¬nines. These particles have been supplied to the Adriatic Sea mostly by rivers, and subsequently redistributed by the sea current, which carries them along and off the west coast.Veličina zrna, udio organske tvari i karbonata određeni su u 5 jezgara holocenskih sedimenta iz srednjeg Jadrana. U istraživanom području prevladava taloženje sitnozrnatih i nekarbonatnih čestica. Na razlike između postaja utječe njihov geografski položaj i hidrodinamički uvjeti na njima, mehaničko trošenja okolnog područja djelomično pod antropogenim utjecajem ali i prisutnost ostataka organizama s karbonatnim skeletom u sedimentu. Iako je istočna obala Jadrana uglavnom karbonatna, na postajama u blizini istočne obale, prisutnost eocenskih flišnih naslaga smanjuje udio karbonata (40,27-48,88%) u sedimentu, a prevladavaju čestice veličine mulja (33,12-56,83%). Na postaji u blizini otoka Visa sediment je uglavnom karbonatan (67,36-76,5%), s najvećim sadržajem čestica veličine pijeska (67,07-70,63%). Porijeklo ovog sedimenta su skeletni ostaci organizama koji su živjeli na morskom dnu, pre-holocenski sedimenti i čestice nastale trošenjem karbonatnih stijena okolnih otoka. Na najdubljoj postaji koja se nalazi blizu zapadne obale Jadranskog mora prevladavaju čestice veličine gline (52 - 70%), a udio karbonata je nizak (31,7-40,5%). Ove glinene čestice su nastale erozijom Alpa i Apenina, a u Jadransko more su dospjele rijekama, te su morskim strujama pretaložene duž zapadne obale

Volume, abundance and biomass of sediment bacteria in the eastern mid Adriatic Sea

Bacterial abundance, biomass, cell volume, and morphological diversity were studied in sediment samples collected from the coastal area of the eastern mid Adriatic Sea. Samples from the topmost 10 cm of sediment were taken monthly from January to December 2002. The number of bacteria varied from 3.54 x 109 cells g–1 in July to 8.08 x 109 cells g–1 in September. Biomass was lowest in May (78 µg C g-1) and highest in December (378 µg C g-1). The volume of the bacteria varied markedly with season, fluctuating from 3.87 x 108 µm3 g-1 in May to 3.12 x 109 µm3 g-1 in December. Cells with a volume smaller than 0.1 µm3 accounted for the largest number of bacteria (62%) and cocci comprised 93% of these cells. More than 80% of all rod cells had a volume smaller than 0.5 µm3. The majority of filamentous cells (63%) belonged to the 0.32 µm3 volume class. Rodshaped cells were dominant in terms of volume (45-72%) and biomass (42-72%) and cocci in terms of abundance (52-70%). Cells smaller than 0.5 µm3 made up 88-94% of the bacteria and 68-84% of the biomass in the summer and 6-44% of the bacteria and and 21-81% biomass in the winter

Study of the office chairs comfort regard to subjects characteristics

Dugotrajno sjedenje na neprikladnim stolicama koje nedovoljno pridržavaju tijelo i uzrokuju nelagodu i umor rezultira neudobnošću sjedenja. Istraživanjem konstrukcija uredskih stolica utvrđene su razlike u osjećaju udobnosti sjedenja na različitim vrstama sjedala. Istodobno je istraživan i utjecaj nekih ljudskih osobina i obilježja na osjećaj udobnosti. U radu su prikazani rezultati provjere statističke značajnosti razlika u subjektivnim procjenama udobnosti/neudobnosti s obzirom na spol, dob, visinu i masu ispitanika, zdravstvene tegobe i navike križanja nogu tijekom sjedenja, i to na četiri različite konstrukcije sjedala. Istraživanja su provedena na 36 ispitanika i sa 16 stolica. Ispitanici su nakon dvodnevnog sjedenja na stolici ocjenjivali osjećaje udobnosti/neudobnosti uz pomoć upitnika i odgovarajući na pitanja o postojanju određenih navika sjedenja i zdravstvenih tegoba. Razlike u procjenama među skupinama ispitanika provjerene su pomoću t-testa za neovisne uzorke. Istraživanje je pokazalo da ne postoje statistički značajne razlike testiranih varijabli i osobina ispitanika, ali da postoje neki trendovi.Prolonged use of anthropologically and ergonomically unsuited office task chair can cause discomfort and problems. The study about construction of office task chairs has shown differences of subjects feelings in the sitting comfort provided by various types of seating fillings. At the same time it was researched influence of some human characteristics on comfort feeling. Paper presents statistically significant differences in subjective evaluation of comfort/discomfort on four different seat constructions regarding to gender, age, height and mass of subjects, health problems and crossing legs habits during sitting. The study included 36 subjects and 16 chairs. After two days use of the chairs the subjects assessed their feeling of comfort and discomfort by ticking statements of the questionnaire about subsistence of specific sitting habits and health problems. Differences in evaluation among subject groups are checked with t-test for independent sample. Study showed no significantly differences in tested variables and subjects characteristics, but there are some trends

Prilog poznavanju raznolikosti školjkaša u Malostonskom zaljevu (Jadran)

Although Mali Ston Bay is an important bivalve aquaculture area and one of the most studied areas in the Adriatic Sea, very little is known about its biodiversity. The goal of the present study was to estimate bivalve diversity in Mali Ston Bay according to the spatial distribution of live bivalves and empty shells. Samples were collected with a 0.1-m2 van VEEN grab at twelve sampling stations in the bay during June 2000. Species were determined in the laboratory and the bivalve assemblage was analyzed using the PRIMER software package. Eighty-two bivalve species were identified, indicating that Mali Ston Bay is an area of high bivalve diversity.Iako je Malostonski zaljev važno područje za akvakulturu školjkaša i jedno od naj- istraživanih područja u Jadranskom moru, vrlo malo je poznato o njegovoj biološkoj raznolikosti. Ovo istraživanje je pokrenuto s ciljem procjene raznolikosti školjkaša u Malostonskom zaljevu na osnovi prostorne raspodjele živih školjkaša i praznih ljuštura. Uzorci su prikupljani sa 0.1 m2 van VEEN grabilom na 12 postaja uzorkovanja smještenih u Malostonskom zaljevu tijekom lipnja 2000. Vrste su određene u laboratoriju i sastav zajednice školjkaša je analiziran pomoću PRIMER programa. Ukupno su određene 82 vrste školjkaša što upućuje da je Malostonski zaljev područje sa visokom raznolikošću školjkaša

Utjecaj suspendirane tvari na akumulaciju kadmija u sediment Kaštelanskog zaljeva, Jadransko more, Hrvatska

Seasonal and spatial distributions of cadmium (Cd) and organic matter (OM) in sediment and suspended matter of the semi-enclosed Kaštela Bay (middle Adriatic Sea) were investigated at four stations during a one year period (April 2000 - April 2001). Samples of surface sediment and suspended matter were collected monthly. One sediment core was sampled at every station at the beginning of the sampling period. Cd concentrations in surface sediment and suspended matter were in the range of 0.082-0.904 mg kg-1 and 0.131-1.057 mg kg-1, respectively. The distribution pattern of Cd between sediment and suspended matter clarified Cd transport throughout the bay. The suspended matter acts as a collector and carrier of Cd in the bay. The higher concentrations in suspended matter were associated with lower concentrations in the sediments, which indicated that sediment resuspension has an important role in the distribution of Cd between sediments and suspended matter. The spatial distribution of Cd in the sediment and suspended matter of Kaštela Bay was in accordance with the prevailing circulation in the bay and indicated a partially anthropogenic origin of Cd. The vertical distribution revealed a decrease of Cd concentration with sediment depth, which also indicated an anthropogenic origin. Seasonal differences in the accumulation of Cd were recorded with concentrations being higher during the autumn-winter season, in accordance with a higher degree of sediment resuspension during this period.U poluzatvorenom Kaštelanskom zaljevu istraživane su prostorna i sezonska raspodjela kadmija i ogranske tvari u sedimentu i suspendiranoj tvari tijekom jedne godine (travanj 2000. – travanj 2001.). Uzorci sedimenta i suspendirane tvari sakupljani su mjesečno na četiri postaje koje su 15-30 m udaljene od obale. Na početku istraživanja na svakoj je postaji uzorkovana po jedna sedimentna jezgra. Granulometrijski sastav sedimenta u istočnom onačišćenom području je pjeskoviti silt, dok je u ostalom dijelu zaljeva pjesak. Izmjereni maseni udjeli kadmija u sedimentu bili su od 0,082 do 0,904 mg kg-1, a u suspendiranoj tvari od 0,131 do 1,057 mg kg-1. Raspodjela kadmija između sedimenta i suspendirane tvari utječe na prijenos kadmija kroz zaljev. Suspendirana tvar je „sakupljač“ i „nositelj“ kadmija u zaljevu. Resuspenzija sedimenta je značajan proces koji doprinosi povećavanju masenih udjela kadmija u suspendiranoj tvari i smanjenju u sedimentu. Prostorna raspodjela kadmija određena je cirkulacijom u zaljevu i ukazuje na antropogeno podrijetlo kadmija. Smanjenje masenih udjela kadmija u dubljim slojevima sedimenta također upućuje na antropogeno podrijetlo kadmija u zaljevu. Povećanje masenih udjela kadmija zabilježeno je tijekom jesenske i zimske sezone kada je proces resuspenzije sedimenta značajniji

MARINE SEDIMENTS CHARACTERISTICS IN THE SPLIT AREA

The distributions of granulometric composition, organic matter and carbonate content were determined in the sediment core at three stations and in the samples from surface sediment at eight stations in Split area (eastern Adriatic Sea). According to average values, clay and silt particles prevail in the sediment core and surface sediment. Average values of organic matter content for the three stations were 7.6 ± 0.9%, with range from 4.9 to 9.9%. In the surface sediment, average values were 6.2 ± 1.8%, with range from 3.9 to 8.9%. In the sediment core samples average values of carbonate were 45.1 ± 4.6%, with the range from 36.6 to 71.7%, while average values of carbonate in surface sediment were 52.5 ± 8.2%, with range from 41.1 to 66.5%. According to the Folk classification, the sediment type at Stations 1 and 2 is mud, and at Station 3 slightly gravelly sandy muds. In the surface sediment, at the four stations, prevailing sediment type is mud, following slightly gravelly sandy mud (at three stations), while sandy mud was determined only at one station According to the Shepard classification in sediment core prevailing sediment type is silty clay, while in surface sediment, sediment type vary from silty clay (clayey silt mixture to silt). Very poorly (2.08) to extremely poorly sorted (6.85) sediment indicated different origin of settled particles (terrigenous and biogenous). The relationship between determined parameters in the sediment was established using the regression analysis (Spearman correlation and Cluster analysis). Results of the Cluster Analysis, using all the investigated parameters (granulometric composition, organic matter and carbonate content) confirmed the granulometric composition as a leading differentiation parameter between investigated sediments

Vertikalna raspodjela kemijskih oblika fosfora i željeza u sedimentu postaja otvorenog mora na području srednjeg Jadrana

Sedimentary phosphorus species concentrations were examined in cores (0-10 cm) from 5 locations in the open middle Adriatic in June 2002. Measurements included organic phosphorus (OP) and inorganic P species: P in biogenic apatite (P-FD), P adsorbed onto iron-oxy/hydroxides (P-Fe), P in authigenic apatite (P-AUT) and P in detrital apatite (P-DET). Total iron (Fe-TOT) and iron-oxyhydroxides (Fe(III)OOH) concentrations were also determined as well as granulometric composition, organic matter (OM), organic carbon (C-ORG) and carbonate content (CA). Sediment pore water measurements included redox-potential (EH) and orthophosphate concentration. All relevant data were subjected to correlation, Cluster and Principal Component Analysis (PCA). Cluster analysis indicated that granulometric composition and carbonate content are the leading factors of distinction between the stations. PCA revealed that the fine fraction of sediments has a key role in the vertical distribution of Fe-TOT and P-ORG. Linkage among P-AUT, P-DET and C-ORG results from river input influence, while association between OM, P-Fe, EH and OP arises from complex internal processes in the sedimentary P cycle.U sedimentu sa 5 postaja otvorenog mora srednjeg Jadrana ispitane su koncentracije različitih oblika fosfora (P ) u jezgrama debljine 0-10 cm. Mjerenja su uključivala organski fosfor (OP ) i anorganske vrste P: P u biogenom apatitu, (P-FD ), P adsorbiran na okside i hidrokside željeza (P-Fe), P u autigenom apatitu (P-AUT ), i P u detritusnom apatitu (P-DET ). Koncentracije ukupnog željeza i željeznih oksi-hidroksida (Fe(III)OO H) su također određene kao i granulometrijski sastav, sadržaj organske tvari (OM), organskog ugljika (C-OR G) i karbonata (CA ) u sedimentu. U pornoj vodi sedimenta su izmjereni redoks potencijal (EH) i koncentracija ortofosfata. Svi su podaci bili predmet korelacijske, Cluster i PC analize. Cluster analiza je ukazala na granulometrijski sastav i sadržaj karbonata kao vodeće čimbenike razlikovanja između postaja. PC analiza je pokazala da sitno-zrnata frakcija sedimenta ima ključnu ulogu u vertikalnoj raspodjeli Fe-TOT i P-OR G u sedimentu. Povezanost između P-AUT , P-DET i C-OR G je rezultat utjecaja riječnog donosa, dok veza između OM, P-Fe, EH and OP proizlazi iz kompleksnih procesa ciklusa P u sedimentu

Assessment of the impact of Atlantic bluefin tuna farming on Adriatic benthic habitats by analysing macroinvertebrate assemblage structure at family level

The rapidly expanding Atlantic bluefin tuna fattening industry is characterized by high stock densities and a high input food biomass in the form of whole bait seafood. The environmental impact of this activity must be effectively monitored within a proper sustainable development framework, to address concerns about the potential adverse effects. However, evaluation of monitoring tools for tuna farming has received less attention than other activities. Based on the principles of key taxa (Pocklington & Wells, 1992), we tested the potential use of changes in benthic macroinvertebrate assemblages, polychaetes and amphipods for this purpose. Applying a non-parametric multivariate approach for monitoring the impact of this aquaculture activity on the benthic habitat, we checked for correlations with the physicochemical environmental variables of the sediment. A hierarchical spatial design was followed, using multiple controls. Amphipods and polychaetes showed dissimilarities between impacted and control locations, with significant differences for total assemblage structure at a taxonomic level of families. Total nitrogen (TN) and total sulfur (TS) concentrations were the variables best associated with these changes for amphipods, and d 13C and total phosphorus (TP) were the best for polychaetes. However, total free sulfides (TFS) and TP were the chemical variables that best indicated the effects on sediment. Using this approach, surrogating the whole benthic assemblage to a single taxocene, our data suggest that monitoring tuna farming impact by comparing the changes in amphipod and polychaete assemblages at family level could be an optimal procedure with an excellent cost/benefit ratio.The study was funded by the Postdoctoral program of the Generalitat Valenciana for DFJ (APOSTD/2012/044)