Search

Discharging untreated ballast waters supports the spread of invasive species. One of the most successful ballast-water mediated biological invasions was a transatlantic transport of the ctenophore Mnemiopsis leidyi to many Eurasian seas, where it has significantly impacted local ecosystems. To prevent its spread to new areas, we studied the survival of different M. leidyi life stages exposed to several eradication techniques. We looked closely into the technical applicability of an onboard thermal treatment by calculating its duration and the required energy to perform it. The duration was considered as a sum of the time to heat ballast tanks by using the engine's waste heat for two types of ships and M. leidyi's eradication. The calculated duration of the proposed treatment allowed us to estimate a minimum travel length undertaken by a specific type of ship to eliminate M. leidyi successfully. The travel length determines the appropriate technique and minimal requirements to eliminate M. leidyi successfully and, thus, can serve as a guideline for a management plan. In conclusion, the proposed onboard treatment would be efficient on smaller ships and minimum distances of 200-300 km depending on the season but not on the short routes where other treatment techniques, e.g. exposure to ultrasonic cavitation or microwave radiation, should be considered.

Kroz godinu dana obavljena je studija stanja okoliša u Pješčanoj uvali, naselju u blizini Pule u južnoj Istri. Pješčana uvala ima problem sa otpadnim vodama zbog naglog rasta i razvoja naselja koje je doveo do diskutabilnih zahvata u gradnji poput spajanja odvoda kišnice i kanalizacije u određenim kućama. Tokom jakih kiša je pritom moguće da se prihvatni kapacitet sustava odvodnje prepuni te da dođe do izljeva mješavine otpadnih i oborinskih voda u uvalu. Stoga su istraženi hidrografski i mikrobiološki parametri uvale. Od hidrografskih parametara istraženi su temperatura, salinitet, pH i saturacija vode kisikom. Od mikrobioloških parametara istražene su koncentracije fekalnih indikatora vrste Escherichia coli, fekalnih streptokoka i ukupnih koliforma te morsku autohtonu mikrobiološku zajednicu gdje su izmjerene koncentracije autotrofnih cijanobakterija i heterotrofnih prokariota i nanoflagelata. Istraživanja su pokazala sezonske oscilacije u sanitarnom stanju uvale. Moguće je pretpostaviti da je uzrok neuravnoteženi kišni režim na području i neadekvatna infrastruktura za prihvat i odvod oborinskih voda. Najviše povišene koncentracije fekalnih indikatora su registrirane za jesensko uzorkovanje, kada su oborine u južnoj Istri najobilnije. Osim za jesen također je za zimu i ljeto bila barem jedna postaja sa povišenim koncentracijama. Plaže za kupanje imale su najniže vrijednosti FI što znači da kupači nisu pri opasnosti. Morska mikrobiološka zajednica imala je povećanu heterotrofnu komponentu, koja je imala raspored u uvali poput fekalnih indikatora. Zaključak je da su se heterotrofi hranili organskom tvari koja je ušla u uvalu s fekalnim indikatorima. Međutim, autotrofna komponenta je pak pokazivala snižene koncentracije, vrlo vjerojatno jer autotrofnim organizmima smetaju promjene hidrografskih uvjeta uzrokovane unosom mješavine voda. Over the course of a year, a study of the state of the environment was carried out in Pješčana uvala, a settlement near Pula in southern Istria. Pješčana uvala has a problem with wastewater due to the rapid growth and development of the settlement, which has led to debatable interventions in construction, such as the connection of rainwater drains and sewage in certain houses. During heavy rains, it is possible for the reception capacity of the drainage system to overflow and for a mixture of waste and rainwater to flow into the bay. Therefore, the hydrographic and microbiological parameters of the bay were investigated. Of the hydrographic parameters, temperature, salinity, pH and water saturation with oxygen were investigated. Among the microbiological parameters, the concentrations of fecal indicators of Escherichia coli, fecal streptococci and total coliforms and marine autochthonous microbiological indicators were investigated, where the concentrations of autotrophic cyanobacteria and heterotrophic prokaryotes and nanoflagellates were measured. Research has shown seasonal oscillations in the sanitary condition of the bay. It is possible to assume that the cause is an unbalanced rain regime in the area and inadequate infrastructure for receiving and draining rainwater. The highest concentrations of fecal indicators were registered for autumn sampling, when the precipitation in southern Istria is the most abundant. Except for autumn, there was also at least one station with elevated concentrations for winter and summer. The bathing beaches had the lowest FI values, which means that bathers are not at risk. The marine microbiological community had an increased heterotrophic component, which was distributed in the bay like faecal indicators. It can be concluded that heterotrophs fed on organic matter that entered the value with fecal indicators. However, the autotrophic component showed reduced concentrations, most likely because autotrophic organisms interfere with the changes in hydrographic conditions caused by the intake of the water mixture.

Iako su močvare stoljećima promatrane kao bezvrijedna i nepotrebna područja u zadnjim se desetljećima taj stav postepeno promijenio. Danas su močvarni ekosustavi prepoznati kao vrlo vrijedna staništa zbog izuzetno visoke produktivnosti te zbog bogatstva vrsta od najsitnijih mikroorganizama pa sve do biljaka i životinja. Cilj rada bio je istražiti sezonsku dinamiku autohtone mikrobne zajednice i fekalnih bakterija u posebnim hidrografskim uvjetima voda slane močvare Palud i usporediti je sa morskom mikrobnom zajednicom u neposrednoj blizini močvare. Područje posebnog ornitološkog rezervata Palud – Palù od posebnog je značaja za sve organizme koje žive na tome području, a močvara koja se nalazi u samome središtu rezervata je specifičan ekosustav na području sjevernog Jadrana. Uzorkovanje se je izvodilo na 9 prethodno određenih postaja, na području posebnog ornitološkog rezervata Palud – Palù, a održalo se je 7 puta u periodu od kraja srpnja 2021., do svibnja 2022. Određena je sanitarna kakvoća vode te brojnost autohtone mikrobne zajednice u močvari, moru te u močvarnom kanalu koji povezuje močvaru s morem. Također je napravljena i statistička analiza podataka radi prikaza korelacije između sezonalnosti i mjerenih abiotičkih čimbenika, kao i grupacija postaja ovisno o poziciji uzorkovanja i ovisno o prisutnosti indikatorskih mikroorganizama ili autohtone mikrobne zajednice. Tijekom toplijih mjeseci (ljeto 2021. i proljeće 2022.) koncentracija indikatora fekalnog onečišćenja, ali i brojnost autohtone mikrobne zajednice je bila veća nego tijekom hladnijih mjeseci (jesen 2021. i zima 2022.). Dobiveni rezultati uspoređeni su s prosječnim podacima za sjeverni Jadran dostupnim u literaturi, kao i s dugoročnim prosjecima podataka za postaju RV001 na 1 NM zapadno od Rovinja. Rezultati su pokazali da hidrografski parametri u močvari imaju velike sezonske oscilacije, ali i da morske mijene imaju izuzetno važnu ulogu u funkcioniranju mikrobne zajednice i čitavog ekosustava. Although wetlands have been viewed as worthless and unnecessary areas for centuries, this attitude has gradually changed in recent decades. Today, wetland ecosystems are recognized as very valuable habitats due to their extremely high productivity and the richness of species, from the smallest microorganisms to plants and animals. The aim of this research is to investigate the seasonal dynamics of the indigenous microbial community and fecal bacteria in the special hydrographic conditions of the waters of the Palud salt marsh and compare it with the marine microbial community in the immediate vicinity of the marsh. The area of the special ornithological reserve Palud - Palù is of special importance for all organisms that live in that area, and the marsh located in the very center of the reserve is a specific ecosystem in the area of the northern Adriatic. Sampling was carried out at 9 previously determined stations, in the area of the special ornithological reserve Palud - Palù and took place 7 times in the period from the end of July 2021 to May 2022. The sanitary quality of the water and the abundance were determined autochthonous microbial communities in the marsh, the sea and in the marsh channel that connects the marsh with the sea. A statistical analysis of the data was also made to show the correlation between seasonality and measured abiotic factors, as well as the grouping of stations depending on the sampling position and depending on the presence of indicator microorganisms or autochthonous microbial communities. During the warmer months (summer 2021 and spring 2022), the concentration of fecal pollution indicators, as well as the abundance of the autochthonous microbial community, was expected to be higher than during the colder months (autumn 2021 and winter 2022). The obtained results were compared with average data for the northern Adriatic available in the literature, as well as with long-term data averages for station RV001 at 1 NM west of Rovinj. The results showed that hydrographic parameters in the marsh have large seasonal oscillations, but also that sea changes play an extremely important role in the functioning of the microbial community and the entire ecosystem.

Obalna staništa su zbog svoje produktivnosti, sekvestracije ugljika, raspršivanja energije valova, zaštite obale od erozije i kruženja nutrijenata priznata kao jedna od najvrjednijih ekosustava na Zemlji. Kako bi se utjecalo na smanjenje pritiska velikog stanovništva i turizma, te potaknulo investitore na odgovorno postupanje prema prirodi, doneseni su brojni zakonski i podzakonski akti kako bi se što bolje reguliralo to područje. Cilj ovog istraživanja bilo je procijeniti utjecaj ski-lifta i pripadajuće infrastrukture na stanje priobalnih zajednica tri godine nakon njegove uspostave i usporediti sa staništima koja su utvrđena prije izgradnje ski-lifta. Uvala Valovine otvorena je prema jugozapadu, ukupne površine oko 0,12 km² i dio je Natura 2000 područja nazvanog „Akvatorij zapadne Istre“. Biocenoze koje su utvrđene u infralitoralu su: Biocenoza sitnih površinskih pijesaka, Biocenoza zamuljenih pijesaka zaštićenih obala, Biocenoza infralitoralnih algi i Biocenoza naselja vrste Posidonia oceanica koja je zbog svoje rijetkosti u Sjevernom Jadranu, vrlo važna i značajna za cjelovitost ekosustava pulskog akvatorija. Za potrebe analize stanja pridnenih staništa u ovom radu u dva navrata korištena je metoda vizualnog cenzusa. Za vrijeme ronjenja unutar cjelovitog zahvata ski-lifta korištena je oprema za autonomno ronjenje i podvodni fotoaparat, te podvodni dron. Prikupljene su direktne informacije s terena o prisutnim staništima i vrstama koje su ondje zatečene. Sve vrste koje nije bilo moguće determinirati in situ, determinirane su u prostorima Fakulteta prirodnih znanosti u Puli uz pomoć ključeva za determinaciju vrsta. Rezultati su pokazali dva vrlo pozitivna učinka ski-lifta u uvali Valovine, od kojih je jedan uporaba infrastrukture ski-lifta kao umjetno stanište sesilnim organizmima, a drugi je onemogućeno sidrenje brodica čime je omogućen oporavak biocenoza u uvali Valovine. Negativan učinak ski-lifta je otpad koji je primijećen u većoj količini u užem obuhvatu ski-lifta. Uzevši u obzir sve navedeno, predlaže se nastavak provođenja monitoring oporavka staništa i praćenje biocenoze, flore i faune ovog područja. Coastal habitats are recognized as one of the most valuable ecosystems on Earth due to their productivity, carbon sequestration, wave energy dissipation, coastal erosion protection and nutrient cycling. In order to reduce the pressures large populations and tourism and to encourage investors to act responsibly towards nature, numerous laws and by-laws were adopted to improve the regulation of coastal area. The aim of this research was to assess the impact of the ski-lift and its associated infrastructure on the state of coastal communities three years after its establishment and to compare it with the habitats that were established before the construction of the ski-lift. Valovine Bay is open to the southwest, with a total area of about 0.12 km² and is part of a Natura 2000 area called "Aquatoria of Western Istria". The biocenoses that have been established in the infralittoral are: Biocenose of fine surface sands, Biocenose of silty sands of protected shores, Biocenose of infralittoral algae and Biocenose of Posidonia oceanica, which, due to its rarity in the Northern Adriatic, is very important and significant for the integrity of the ecosystem of the Pula sea area. For the purpose of analyzing the state of habitats in this work, the visual census method was used on two occasions. During the diving within the complete ski-lift infrastructure, equipment for SCUBA diving, an underwater camera and an underwater drone were used. Direct information was collected from the field about the habitats present and the species found there. All species that could not be determined in situ were determined in the premises of the Faculty of Natural Sciences with the help of keys for species determination. The results showed two very positive effects of the ski-lift in Valovina bay, one of which is the use of the ski-lift infrastructure as an artificial habitat for sessile organisms, the second is the inability to anchor boats, thereby enabling the recovery of the biocenosis in Valovina bay. The negative effect of the ski-lift is the increased amount of waste in the narrower scope of the ski-lift. Considering all of the above, it is suggested to continue the monitoring of habitat recovery and monitor the biocenoses, flora and fauna of this area.

Područja estuarija od velikog su ekološkog, estetskog, ekonomskog i kulturološkog značaja te kao takvi spadaju među najproduktivnije i najdinamičnije ekosustave na Zemlji. Zbog specifičnih uvjeta kao što su miješanja vodenih masa različitog saliniteta i obilja hranjivih tvari prisutnih na tom području, estuariji se smatraju vrlo važnim staništima za mnoge vrste kopnenih i vodenih organizama što ih čini staništima s izrazito visokom biološkom raznolikošću. Primjer takvog područja nalazi se na zapadnoj obali Istre, poznato pod nazivom Limski zaljev. Unutrašnje područje Limskog zaljeva pod jakim je utjecajem vrulja što ga čini izrazito biološki produktivnim područjem. U ovom istraživanju pratili su se hidrografski parametri – temperatura, salinitet, pH vrijednost i saturacija kisikom i mikrobiološki pokazatelji poput brojnosti morske mikrobne zajednice, te je provedena sanitarna kontrola mora kroz četiri godišnja doba. Postavljena hipoteza o značajnom utjecaju vrulja na hidrografske parametre i brojnost mikrobne zajednice u površinskom dijelu zaljeva, te hipoteza da obalne vrulje u Limskom zaljevu predstavljaju potencijalni izvor fekalnih bakterija potvrđene su dobivenim rezultatima. Temeljem provedenog istraživanja može se zaključiti da u obalnom dijelu Limskog zaljeva dotok slatkih i hladnih voda putem vrulja dovodi do promjena hidrografskih uvjeta čime nastaju specifični uvjeti ekosustava koji su pogodni heterotrofnoj komponenti mikrobne zajednice. Uz to, povremena prisutnost većih koncentracija fekalnih indikatora u slatkoj vodi iz vrulja negativno utječe na sanitarnu kvalitetu mora u zaljevu. Potrebno je provoditi redovne sanitarne kontrole mora i precizno identificirati i sanirati izvore fekalnog onečišćenja u svrhu očuvanja od antorpogenog onečišćenja ovog posebnog rezervata u moru. Estuary areas are of great ecological, aesthetic, economic and cultural importance and as such are among the most productive and dynamic ecosystems on Earth. Due to specific conditions such as the mixing of water masses of different salinity and the abundance of nutrients present in the area, estuaries are considered very important habitats for many types of terrestrial and aquatic organisms, which makes them habitats with an extremely high biological diversity. An example of such an area is located on the west coast of Istria, known as the Lim Bay. The inner area of the Lim Bay is strongly influenced by underwater freshwater springs, which makes it an extremely biologically productive area. In this research, hydrographic parameters were monitored - temperature, salinity, pH value and oxygen saturation, and microbiological indicators such as the abundance of the marine microbial community, and sanitary control of the sea was carried out through four seasons. The hypothesis about the significant influence of underwater freshwater springs on hydrographic parameters and the abundance of the microbial community in the surface part of the bay, and the hypothesis that coastal underwater freshwater springs in the Lim Bay represent a potential source of fecal bacteria, were confirmed by the obtained results. Based on the conducted research, it can be concluded that in the coastal part of the Lim Bay, the inflow of fresh and cold water through underwater freshwater springs leads to changes in hydrographic conditions, which creates specific ecosystem conditions that are suitable for the heterotrophic component of the microbial community. In addition, the occasional presence of higher concentrations of fecal indicators in fresh water from underwater freshwater springs negatively affects the sanitary quality of the sea in the bay. It is necessary to carry out regular sanitary controls of the sea and precisely identify and remediate the sources of fecal pollution in order to protect this special reserve in the sea from anthropogenic pollution.

Istarski poluotok je zahvaljujući svojem reljefu i klimatskim uvjetima od davnina obilježen močvarnim područjima kao i stalnim i privremenim lokvama koje predstavljaju žarišta bioraznolikosti. Sediment močvara i lokvi predstavlja jedan od temeljnih staništa koji bilježi dugoročne uvijete i promjene u takvim sustavima. Stoga, proučavanje mikrobne zajednice u sedimentima, koja je najbrojnija komponenta bentosa lokvi, može doprinijeti boljoj interpretaciji ukupnog ekološkog stanja spomenutih vodenih tijela a uz kvantifikaciju fekalnih bakterija moguće je prepoznati i kvantificirati razinu određenih potencijalnih antropogenih pritisaka za ekosustave i predlaganje daljnjih mjera za zaštitu ovih područja. Istraživanje je provedeno kroz zimu i ljeto na šest različitih lokacija jugozapadne Istre. Brojnost heterotrofnih prokariota u sedimetima određena je pomoću epifluorescentntnog mikroskopa dok je sanitarna kvaliteta sedimenta odrađena metodom najvjerojatnijeg broja. Na temelju prikupljenih podataka može se zaključiti da je ekološko stanje analiziranih sedimenata umjerene kvalitete, pogotovo kod vodenih tijela u neposrednoj blizini ljudskih naselja. Dakle, potrebno je poduzeti odgovarajuće mjere kako bi se spriječio dodatni unos hranjivih soli, organske tvari ili zagađivala s prometnica, kako bi se stabilnost spomenutih vodenih tijela mogla dugoročno očuvati. Thanks to its landscape and climatic conditions, the Istrian peninsula has long been characterized by wetlands as well as permanent and temporary ponds that represent hotspots of biodiversity. The sediment of swamps and ponds represents one of the fundamental habitats which records long-term conditions and changes in such systems. Therefore, the study of the microbial community in sediments, which is the most numerous component of the benthos of ponds, can contribute to a better interpretation of the overall ecological state of the aforementioned water bodies, and with the quantification of fecal bacteria, it is possible to recognize and quantify the level of certain potential anthropogenic pressures on the ecosystems and propose further measures for the protection of these areas. The research was conducted during winter and summer at six different locations in southwestern Istria. The number of heterotrophic prokaryotes in the sediments was determined using an epifluorescence microscope, while the sanitary quality of the sediment was determined using the most probable number method. Based on the collected data, it can be concluded that the ecological condition of the analyzed sediments is of moderate quality, especially in water bodies in the immediate vicinity of human settlements. Thus, it is necessary to take appropriate measures to prevent the additional intake of nutrient salts, organic matter or pollutants from roads, so that the stability of the mentioned water bodies can be preserved in the long term.

U ovom diplomskom radu analizirani su uzorci sedimenta, morskih cvjetnica i algi, te je određena brojnost mikrobne zajednice tijekom proljeća, ljeta i jeseni 2021. g., i to u uvalama Ribnjak, Funtana i Veštar na zapadnoj obali Istre. Karakteristike sedimenta u uvalama odraz su izloženosti taložnog okoliša i različitog donosa materijala s kopna. Stanje livada cvjetnica i s njime povezana brojnost mikrobne zajednice su pod utjecajem čovjeka i karakteristika sedimenta. Uvala Ribnjak je pod manjim antropogenim utjecajem, a sadrži muljevit sediment i očuvanu livadu cvjetnica. U uvali Veštar livada u karbonatnom pijesku je značajnije devastirana, vjerojatno radi turističkih aktivnosti, a mikrobna zajednica je najmanje zastupljena. Na uglavnom muljevitom dnu uvale Funtana livadu cvjetnica degradira utjecaj invazivne alge, a moguć je i utjecaj turističkih aktivnosti. In this thesis sediment, seagrass, and algae together with microbial abundancy were analysed in Ribnjak, Funtana, and Veštar Bays along the western Istrian coast during spring, summer and, autumn 2021. Sediment characteristics in all bays are the result of sedimentary environment exposure together with various inputs of terrigenous material. Seagrass meadow conditions and related microbial abundancies reflect the anthropogenic influence and sediment nature. Ribnjak Bay with muddy sea bottom and seagrass meadow in good condition is the least affected by human activities. Veštar Bay meadow, developed in carbonate sand, is significantly degraded, probably due to the tourism, while its microbial community is of the lowest abundance. Mostly muddy sea bottom of the Funtana Bay is covered by a partially degraded seagrass meadow, probably due to the competition of invasive algae, while touristic activities is not excluded.

Alohtoni rebraš Mnemiopsis leidyi je želatinozni, invazivni organizam koji se odnedavno redovito pojavljuje u sjevernom Jadranu. U europskim morima se prvi puta pojavio u Crnom moru gdje je unesen balastnim vodama iz Atlantika i gdje je ubrzo stekao reputaciju izrazito nepoželjnog morskog organizma. Naime, uslijed masovnih pojava rebraša istrijebljen je gotovo čitav fond zooplanktona, što je, na tom području u konačnici, dovelo do kolapsa ribarstva. Kako bi se ustanovila prostorno-vremenska dinamika populacije M. leidyi i kakve utjecaje ostvaruju na planktonsku zajednicu i inćune (kao predstavnike planktivorne ribe) u sjevernom Jadranu, analizirani su brojni kemijski, biološki i fizikalni parametri. Rezultati pokazuju da pojave ovog zooplanktonskog organizma uvelike ovise o geostrofičkim strujanjima, dok širenje i opstanak populacije značajno ograničava dostupnost hrane i temperatura mora. Pojave M. leidyi uz istočnu obalu vezuju se uz topliji dio godine i rezultat su sekundarnog širenja iz zimskih utočišta na zapadnom dijelu sjevernog Jadrana, dok su maksimumi brojnosti krajem ljeta povezani s povoljnim morskim strujanjima. Nadalje, M. leidyi istovremeno podržavaju niže i oslabljuju više trofičke razine organizama. Duga razdoblja visoke brojnosti M. leidyi dovode do akumulacije labilne organske tvari koja je pogodna za mikrobnu razgradnju, te ujedno i izvor hranjivih soli. Takav disbalans u sustavu utječe na rast brojnosti pikoplanktona i njihovih predatora, heterotrofnih nanoflagelata, čime se podržava mikrobna petlja, dok visoko-efikasna i neselektivna prehrana ovog rebraša, u sprezi s drugim pritiscima na riblji fond, mijenja prostorne obrasce populacije inćuna za vrijeme mrijesta, ali i zooplanktonsku zajednicu. Kako je u cilju sprječavanja posljedica pojava M. leidyi važno ograničiti širenje populacije rebraša, u posljednjem je dijelu ovog rada predložena prikladna obrada balastnih voda. Alien comb jelly Mnemiopsis leidyi is a gelatinous, invasive organism that is since recently is regularly appearing in the northern Adriatic. Its first appearance in the European seas was in the Black Sea, where it arrived in ballast tanks from the Atlantic and soon gained a reputation as a notorious marine invader. Large M. leidyi swarms depleted the entire zooplankton pool, leading to the collapse of fisheries. To depict the spatiotemporal dynamics of the M. leidyi populations and identify their impacts on the plankton community and anchovies (as representatives of planktivore fish) in the northern Adriatic, different chemical, biological and physical parameters were analysed. The results show that the appearance of this zooplankton organism is largely dependent on the geostrophic flow, while its spread and survival limit food availability and water column temperature. Occurrence along the eastern coast is associated with warmer seasons as a result of secondary dispersion from M. leidyi winter refuges in the northwest and maxima abundances in late summer with favourable sea currents. Moreover, M. leidyi simultaneously supports lower trophic levels while interfering with transport to the higher levels. Especially long high-abundance periods provide a large amount of organic matter, in most part labile and, thus, suitable for microbial digestion that, as follows, the release of nutrients. Furthermore, such an imbalance in the system leads to an increased abundance of picoplankton and their predator heterotrophic nanoflagellate, stimulating the microbial loop. Besides, a highly efficient and non-selective comb jelly diet, combined with other stressors on fish stocks, affects the spatial patterns of anchovy spawning areas and the zooplankton community. It is most important to limit M. leidyi spread to prevent adverse consequences; thus, ballast water treatments are proposed in the last part of this thesis.