Repository of the Department of Marine Studies at the University of Split
Not a member yet
318 research outputs found
Sort by
MORPHOLOGICAL AND PHYSIOLOGICAL ADAPTATIONS TO LIFE IN EXTREME ENVIRONMENTAL CONDITIONS
No full textU ovom završnom radu su predstavljena i sažeta dosadašnja znanja temeljnih prilagodbi organizama na život u ekstremnim ekološkim uvjetima. U antropološkom pogledu, staništa nepogodna za čovjeka, imenovana su ekstremnima. Neka od njih smatrana su previše ekstremnima da bi podržali mikroorganizme. Međutim, organizmi su evoluirali i uspješno žive u svim takvim staništima, a nazivamo ih ekstremofilima. Ovisno o njihovima optimalnim uvjetima rasta nazivaju se termofili, psihrofili, acidofili, halofili, itd. Prilagodbe tih organizama su raznolike, a neke od njih su sinteza enzima sa specifičnim strukturnim značajkama, mehanizmi popravaka DNA, jedinstvene stanične membrane te regulacija veličine tijela. Prikazani su primjeri eksperimenata provedenih na dobrim modelima za istraživanje morfoloških i fizioloških prilagodbi. Dugoživci su mikroskopske životinje jedinstveno prilagođene velikom rasponu ekoloških ekstrema. Pokazano je da mogu preživjeti ekstreme ulaskom u kriptobiozu, ali i u aktivnom stanju. Mediteranska biljka, bijeli bušin, kolonizira ekstremna geotermalna područja. Proučavanje njezinih listova pokazalo je stresom inducirane prilagodbe koje joj omogućavaju preživljavanje. Multidisciplinarna istraživanja ekstremofila omogućuju razumijevanje pojave i razvoja života na jedinom planetu na kojem je do sada poznat te su ključna za traženje života u svemiru.This thesis presents and summarizes current knowledge on fundamental adaptations of organisms to life in extreme ecological conditions. In an anthropocentric view, environments hostile to man were designated as extreme. Some of them have originally been considered too extreme to support microbial life. However, organisms have evolved and live in such environments and they are called extremophiles. Depending on their optimal growth conditions, they are named thermophiles, psychrophiles, acidophiles, halophiles, etc. Adaptations in mentioned organisms are diverse and some of them are synthesis of enzymes with specific structural features, DNA repair mechanisms, unique cell membranes and regulation of body size. In this paper examples of experiments conducted on useful models to explore morphological and physiological adaptations are shown. Tardigrades are microscopic animals uniquely adapted to a range of environmental extremes. It is shown that they can survive extremes entering cryptobiosis but even in their active states they can be extremely tolerant. The Mediterranean shrub colonizes extreme geothermal fields. The analyses of its leaves showed stress-induced adaptations involved in their surviving. Multidisciplinary research on extremophiles allows understanding how life appeared and evolved on the only planet where it is so far known and it is crucial if we are to look for life in space
DISTRIBUTION OF NUTRIENTS IN THE WATER COLUMN OF ADRIATIC COASTAL SITES
No full textTema završnog rada je raspodjela koncentracija nutrijenata (ortofosfata, ukupnog anorganskog dušika i ortosilikata) u vodenom stupcu priobalnih postaja Jadranskog mora. U radu će se uz osnove biogeokemijskih ciklusa navedenih elemenata pojasniti i metodologija mjerenja koncentracija nutrijenata u morskoj vodi. Iz dostupnih podataka bit će prezentirani rezultati prostorne i vremenske raspodjele nutrijenata za priobalne postaje Jadranskog mora u razdoblju od 1994. godine do 2010. godine.This thesis presents distribution of nutrients (orthophosphates, total dissolved nitrogen and orthosilicates) in the water column of Adriatic coastal sites. The biogeochemical cycles of these elements will be presented, as well as the methods of measuring of nutrients in the seawater. Spatial and temporal distribution of nutrients will be presented from available data collected during 1994 - 2010 period at Adriatic coastal sites
ANTHROPOCENE-ECOLOGICAL IMPACT OF HUMANS ON THE MARINE ENVIRONMENT
No full textAntropogeni utjecaj je sve značajniji na Zemlji te dovodi do različitih promjena na kopnu te posljedično tome i u moru. U radu su opisane geomorfološke aktivnosti u koje je uključen čovjek, te posljedične promjene koje nastaju u morskom okolišu, prvenstveno u obalnom području. U radu su navedeni i neki primjeri devastacije obalnog područja. Zbog ubrzanog razvoja, sve veće prometne povezanosti, velikog razvoja svjetskog turizma, a time posljedično i razvoja turizma na Jadranu, čovjek ne razmišljajući o dugoročnim posljedicama nepovratno devastira obalu. Svrha pisanja ovog rada je ukazivanje na aktualni problem u našoj blizini, za koji je potrebno podizanje svijesti, strateški plan i održivo upravljanje.Anthropogenic impacts are more and more important on the Earth and lead to different changes in the land and consequently in the sea. The paper describes the geomorphological man involved activities, and the consequential changes that occur in the marine environment, primarily in the coastal area. Some examples of devastation of the coastal area are also mentioned. Due to the accelerated development, the increasing traffic connections, the great development of world tourism, and consequently the development of tourism on the Adriatic, one does not think about the long-term consequences of irretrievably devastating the coast. The purpose of writing this paper is to point to the current problem in our neighbourhood, which requires raising awareness, strategic planning and sustainable management
Measurement of wave pressure and wind speed in the Split marine area
Get PDFU radu je dan opis instrumenta „Quattuor 45“ i definiranje mjere pritiska morskog vala te prikaz mjerenja pritiska morskog vala i brzine vjetra na ispitivanom području. Na samom početku rada, opisano je dosadašnje opažanje morskih valova te teorijski opis valova koji se približavaju obali. U radu je imenovan instrument prema načinu dobivanja podataka te je, uz slike bokocrta i nacrta, opisan instrumenta. Isto tako, opisano je sidrište instrumenta, koje je napravljeno od dva betonska bloka, kako bi osigurali horizontalnu stabilnost instrumenta. Uz pomoć plutače na instrumentu osigurano je vertikalno praćenje vrha vala pa s horizontalnom stabilnošću i vertikalnim praćenjem vrha vala dolazimo do reprezentativnog podatka o pritisku morskog vala. Elektronički dio instrumenta se sastoji od glavnog čipa „Arduino“, memorije čipa „Arduino“, četiri mjerne ćelije s odgovarajućim modulima te senzora brzine vjetra. Nakon završenog mjerenja, bazu podataka otvaramo u programu Excel te slijedi detaljna obrada podataka. U radu je detaljno opisana mjera pritiska morskog vala izražena u mjernoj jedinici kN/m2. Mjerenja su prikazana višestrukim linijskim grafikonom gdje je na lijevoj y osi prikazan pritisak morskog vala, a na desnoj y osi je prikazana brzina vjetra u odnosu na vrijeme mjerenja koje je prikazano na x osi.In this paper the description of instrument called "Quattuor 45" and definition of wave pressure measurements are shown. Special attention is given to measurement of wave pressure created by the wind forcing and wind speed in the investigated area. The study begins with theoretical review and numerous up to date investigations related to the waves approaching the coast. Also, it shows the detailed schematic view of the instrument that is enriched with pictures from ground plan and side view. Horizontal stability of the instrument is achieved by anchorage which relies on two concrete blocks. Vertical wave peak monitoring is ensured by two floats inside the instrument and one float above the instrument. The synthesis of horizontal stability and vertical wave peak monitoring allows to create a representative data base for wave pressure measuring. Namely, the electronic part of the instrument consists of the "Arduino", its memory, four load cells with the appropriate modules and the wind speed sensor. The next part of the research is dedicated to data processing. All results from measurements are stored automatically in the data base and after that detailed processing is carried out in the MS Excel. The results of the wave pressure measurement are expressed by the measuring unit kN/m2. This paper also gives a graphical presentation of the results by multi-line graph. The wave pressure is presented on the left vertical axis, while the wind speed is shown on the right vertical axis. The time of measurement is displayed on the horizontal axis
Effects of hypoxia on benthic macrofauna
No full textHipoksija je stanje smanjene koncentracije kisika na nekom području. Poznato je da 21% svih plinova u atmosferi čini kisik, ali koncentracija otopljenog kisika u morskoj vodi znatno je niža i iznosi otprilike 1% te varira lokalno, ovisno o prisutnosti fotosintetskih organizama i relativnoj udaljenosti od površine. Smanjenje kisika je fenomen koji se pojavljuje u vodenim sredinama i dovodi do točke gdje postaje štetno za vodene organizme koji žive u tim područjima. Hipoksija dovodi do smanjene reprodukcije riba te konačno njihove velike smrtnosti. Hipoksija je najčešće posljedica eutrofikacije, unosa dodatnih nutrijenata, te cvjetanja fitoplanktona. Da bi se prethodno oštećeni ekosustav vratio u ravnotežu, prvenstveno treba riješiti problem eutrofikacije i pronaći načine kako smanjiti unos dodatnih nutrijenata.Hypoxia is a condition of reduced oxygen concetration in some area. It is known that 21% of all gases in the atmosphere is oxygen, but the concentration of dissolved oxygen in seawater is considerably lover and is about 1% and varies locally, depending on the presence of photosynthetic organisms and the relative distance from the surface. Oxygen depletion is a phenomenon that occurs in aquatic media and leads to a place where it becomes harmful for aquatic organisms living in those areas. Hypoxia leads to reduced fish reproduction and finally their high mortality. Hypoxia is most likely a result of eutrophication, additional entry of nutrients and phytoplankton blooms. To restore previously damaged ecosystem to equilibrium, the problem of eutrophication must be solved and we must find ways of how to reduce the intake of additional nutrients
Distribution of viruses in the deep Adriatic
No full textU okviru ovog rada analiziran je sastav mikrobnih zajednica mezopelagičkog i batipelagičkog područja srednjeg i južnog Jadranskog mora. Analizirana je brojnost virusa, heterotrofnih bakterija, heterotrofnih nanoflagelata, cijanobakterija roda Synechococcus i Prochlorococcus. Određen je omjer virusa i bakterija i bakterijska produkcija, te su unutar skupine heterotrofnih bakterija prikazani udjeli High Nucleic Acid (HNA) i Low Nucleic Acid (LNA) grupa. Određene su koncentracije otopljenog O2, NO3, PO4, SiO4 te Chl a (klorofil a), te su uz to mjerni i temperatura i salinitet kao najbitniji abiotički čimbenici. Virusna brojnost na istraživanom području bila je u rasponu od 1,83 ± 1,54 x106 VLP mL-1 do 12,19 ± 2,73 x106 VLP mL-1, te je brojnost virusa u prosjeku bila 22,3 puta veća nego brojnost heterotrofnih bakterija na svim postajama. Na brojnost virusa najznačajnije su utjecale brojnosti heterotrofnih bakterija i heterotrofnih nanoflagelata, dok su ostali mjereni parametri imali manji značaj za brojnost virusa.The composition of the microbial communities of the mesopelagic and bathypelagic regions of the central and south Adriatic Sea was analyzed in this thesis. The abundance of viruses, heterotrophic bacteria, heterotrophic nanoflagellates, and cyanobacteria (Synechococcus and Prochlorococcus) were analyzed. The viruses to bacteria ratio, bacterial production, and the share of High Nucleic Acid (HNA) and Low Nucleic Acid (LNA) groups within the heterotrophic bacteria were determined. Concentrations of dissolved O2, NO3, PO4, SiO4 and Chlorophyll a were determined, as well as measurement of temperature and salinity as the most important abiotic factors. Viral abundance in the investigated area ranged from 1.83 ± 1.54 x 106 VLP mL-1 to 12.19 ± 2.73 x 106 VLP mL-1, and the number of viruses on average was 22.3 times higher than the number of heterotrophic bacteria at all stations. The number of viruses was significantly affected by heterotrophic bacteria and heterotrophic nanoflagellates, while the other measured parameters had minor significance for the number of viruses
Morphology and morphometry of Nephrops norvegicus
No full textTijekom istraživanja ukupno je prikupljeno i analizirano 188 jedinki škampa, Nephrops norvegicus na području istočnog Jadrana, raspona ukupne dužine tijela od 9,0 do 14,5 cm (11,46 ± 1,07 cm) i mase od 11,00 do 42,50 g (23,83 ± 6,64 g). Dužinsko – maseni rast škampa je negativno alometrijski (b = 2,544). Jedino se odnosi dužine glavenog oklopa (karapaksa) i ukupne dužine tijela (LC/LT), dužine dactylusa i ukupne dužine tijela (L1Q/LT) i dužine prvog para nogu za plivanje i dužine karapaksa (LPLE/LC) smanjuju s povećanjem ukupne dužine tijela.In the present study, a total of 188 specimens of the Norway lobster, Nephrops norvegicus, ranging from 9.0 to 14.5 cm (11.46 ± 1.07 cm) in total length and from 11.00 to 42.50 g (23.83 ± 6.64 g) in weight were collected and analysed in the eastern Adriatic. The length – weight relationship showed a negative allometric growth (b = 2.544). Only relationships of the carapace length and total length, dactylus length and total length, the first pleopod length and carapace length decreased with increasing total length of the Norway lobster
Viruses in the marine environment
No full textS koncentracijom u rasponu od 107 čestica po mililitru površinske morske vode, virusi su najbrojnija skupina mikroorganizama u morskom okolišu. Virusi inficiraju sva živa bića, od prokariota do velikih sisavaca poput kitova. Virusi značajno utječu na brojnost i sastav bakterija, ali i fitoplanktonskih vrsta uslijed čega mogu utjecati na biogeokemijske cikluse. Lizijom bakterijskih stanica otpuštaju se otopljene organske tvari koje postaju ponovno dostupne ostalim organizmima. Nadalje, virusi sudjeluju u horizontalnom prijenosu gena među bakterijskim populacijama. Morski virusi također predstavljaju najveći spremnik genetičkog materijala u oceanima te značajno pridonose biološkoj raznolikost.Viruses are the most numerous group of microorganisms in the marine environment, with a concentration ranging from 107 particles per millilitre of surface water. Viruses infect all living creatures, from prokaryotes to large mammals such as whales. Viruses significantly affect the abundance and composition of bacteria, but also phytoplankton, which can affect biogeochemical cycles. Through lysis of bacterial cells, the dissolved organic matter is released, and it becomes re-available to other organisms for use. Furthermore, viruses participate in the horizontal transmission of genes among bacterial populations. Marine viruses also represent the largest reservoir of oceanic genetic material and significantly contribute biodiversity
Evolution of viruses
No full textU ovom radu predstavljene su ideje i najnovija otkrića o evoluciji i podrijetlu virusa. Virusi, kao brojni biološki entiteti koji inficiraju sav poznati živi svijet, vrlo su raznoliki, a njihovo djelovanje složeno. Samim time evolucijski procesi virusa su još uvijek nedorečeni , a njihovo podrijetlo je vrlo kompleksno. Trenutno su aktualne tri glavne hipoteze koje opisuju podrijetlo virusa: progresivna, ili hipoteza bijega, regresivna ili hipoteza redukcije i hipoteza „prvo virusi“. Zbog velike raznolikosti među virusima, biolozi su naišli na problem klasifikacije i povezivanja tih bioloških entiteta s konvencionalnim stablom života. Virusni genomi bakterija, arheja i eukariota bitno su različiti. Brojnim filogenetskim analizama različitih klasa virusa, evolucijski procesi ovih elemenata postaju sve jasniji i time pružaju bolji uvid u ovaj jedinstveni i još uvijek poprilično misteriozan svijet.This thesis presents the latest ideas and discoveries on the evolution and origin of the viruses. Viruses, as abundant biological entities that are infecting all forms of life known today, are very complex and diverse. Thus, their evolutionary processes are still unclear and complex, and their origin is very diverse. The three main hypotheses of viral origin are progressive, or escape hypothesis, regressive or hypothesis of reduction and, the virus first hypothesis. Because of their wide variety, biologists have been struggling to classify viruses and associate them within the conventional tree of life. The viral genomes of the three domains of cellular life (bacteria, archaea, and eukaryotes) are significantly different. With numerous phylogenetic analyses of different classes of viruses, the evolutionary processes of these elements are becoming clearer and thus provide a better insight into this unique and still quite mysterious world
Verrucotoxin in stonefish
No full textKamena riba (Synancea verrucosa, Bloch & Schneider, 1801) jedna je od najsmrtonosnijih
riba na svijetu. Verukotoksin je osnovni sastojak otrova kamene ribe. Ubod bodlje leđne
peraje uzrokuje intenzivnu bol, grčenje mišića, paralizu, sniženje krvnog tlaka, respiratorne
smetnje, kardiovaskularni kolaps, a često može imati i smrtonosni ishod. Zabilježeno je da
verukotoksin može modulirati Ca2+ kanale i ATP osjetljive K+ kanale (KATP)u žabljim
atrijskim vlaknima inducirajući hipotenziju, a također ima i hemolitičko djelovanje.
Međutim, stanični i molekularni mehanizmi toksičnosti verukotoksina, a naročito njegove
kardiotoksičnosti prema srcu sisavaca, još nisu u potpunosti istraženi. Rezultati upućuju na to
da verukotoksin djeluje na KATP kanale putem muskarinskih M3 receptora. Ova otkrića
omogućuju bolje razumijevanje toksičnih učinaka verukotoksina iz otrova kamene ribe.Stonefish (Synancea verrucosa, Bloch & Schneider, 1801) is one of the deadliest fish in the
world. Verrucotoxin is the main ingredient of the stonefish venom. A sting of the dorsal spine
causes intensive pain, convulsions, paralysis, hypotension, respiratory distress, collapse of a
cardiovascular system, and often can have a deadly outcome. It has been reported that
verrucotoxin can modulate Ca2+ channels and ATP-sensitive K+(KATP)channels in frog atrial
fibers inducing hypotension, and also it has hemolytic activity. However, the cellular and
molecular mechanisms of verrucotoxin toxicity, especially its cardiotoxicity towards the
mammalian heart, have not yet been fully investigated. The results suggest that verrucotoxin
inhibits KATP channels through the muscarinic M3 receptor pathway. These findings allow us
a better understanding of the toxic effects of verrucotoxin from stonefish