1. Spatially explicit individual-based model reveals the mauve stinger jellyfish distribution in the Mediterranean SeaMartin Vodopivec, Alenka Malej, 2025, izvirni znanstveni članek Povzetek: The mauve stinger Pelagia noctiluca is a holoplanktonic oceanic jellyfish known for its painful sting and large outbreaks at irregular intervals. As jellyfish field observations are almost exclusively limited to coastal regions, there are many unknowns about the spatial and temporal dynamics of most species. We approach the problem using a spatially explicit individual-based model for the mauve stinger in the Mediterranean Sea. The newly developed module for the OpenDrift Lagrangian particle tracking tool includes diel vertical migrations, fooddependent growth modeled on Michaelis–Menten kinetics, and custom mortality related to shallow waters and stranding. In the first part of the study, we analyze the resulting parameter space searching for solutions that ensure a stable Pelagia noctilucapopulation in the western Mediterranean Sea. In the second part, we conducted several 21-year simulations. Despite its relative simplicity, the model reveals for the first time the dynamic spatio-temporal distribution of Pelagia noctiluca. We demonstrate how spatially explicit individual-based model can be used to generate a realistic spatio-temporal distribution of marine zooplankton, even with a limited set of observations and loosely constrained parameters. The model code is easy to modify and freely available.
Ključne besede: individual-based model, agent-based model, zooplankton, Lagrangian particle tracking, ocean circulation, jellyfish
Objavljeno v DiRROS: 05.06.2025; Ogledov: 856; Prenosov: 482
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2. Macrojellyfish (Scyphozoa and Ctenophora) in two enclosed marine systems (the sea of Marmara and Adriatic sea) : a reviewMelek Isinibilir, Alenka Malej, Davor Lučić, Martin Vodopivec, 2024, samostojni znanstveni sestavek ali poglavje v monografski publikaciji Povzetek: Although geographically well apart, there are interesting similarities between the ecosystems of the Sea of Marmara and the Adriatic Sea. In this study, following an evaluation of the ecological problems as well as oceanography, productivity, plankton biomass of these seas, macro-jellyfish ecology of the two ecosystems were discussed comparatively. The Sea of Marmara and the Adriatic Sea are among the areas where increases in jellyfish and mucilage events have been observed in recent decades. Environmental problems such as global warming, oxygen depletion, eutrophication, overfishing, intense maritime traffic, and habitat destruction are causing opportunistic and alien species to increase in both abundance and number of species. As biodiversity declines due to habitat destruction, so does the ecosystem’s means and ability to combat the invasion of alien species in both ecosystems. Accordingly, disruption of lower food chains can put pressure on the entire ecosystem and affect socio-ecological prospects. The number of species of Scyphozoa and Ctenophora was found to be higher in the Adraitic Sea compared to the Sea of Marmara. Mass occurrences with a clear seasonal pattern and related to the geographical location were observed for Aurelia aurita, Rhizostoma pulmo, Chrysaora hysoscella and non-native Mnemiopsis leidyi in the Marmara Sea. However, although A. aurita and R. pulmo show widespread blooms according to the seasons and regions in the Adriatic Sea, C. hysoscella and M. leidyi produced blooms limited to a few areas. Negative and positive interactions of macrojelyfishes with human were also considered. Semi-enclosed seas such as the Sea of Marmara and the Adriatic Sea are representative of many temperate coastal waters where climate change and anthropogenic stressors are increasing, and the ecosystem has changed from a fish-dominated to a jellyfish-dominated ecosystem.
Ključne besede: jellyfish, eutrophication, diversity, introduce, fisheries
Objavljeno v DiRROS: 07.05.2025; Ogledov: 725; Prenosov: 451
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3. Feeding habits of the invasive ctenophore Mnemiopsis leidyi in the Gulf of Trieste (Adriatic Sea)Borut Mavrič, Danijel Ivajnšič, Davor Lučić, Alenka Malej, Lovrenc Lipej, 2025, izvirni znanstveni članek Povzetek: The diet of the invasive ctenophore Mnemiopsis leidyi in the Gulf of Trieste was examined during its peak occurrence in the summer and early-autumn months (July to October) from 2017 to 2019, through the analysis of stomach contents. Altogether 506 specimens were individually caught for the analysis. A total of 3215 prey items were isolated and identified. Copepods emerged as the primary prey (relative abundance 66.7%), followed by cladocerans (7.7%), and bivalve larvae (6%). Notably, specimens of M. leidyi constituted a significant portion of the diet (5.4.%), providing further evidence of cannibalism within this species. Copepods were also the most commonly occurring prey items in the diet of M. leidyi. Most of them were represented by calanoid and cyclopoid nauplii (48.2%), followed by a harpacticoid M. norvegica (28.3%), and calanoids (26.8%). Other frequently occurring taxa were bivalve larvae (19.3%), M. leidyi (18.7%), and cladoceran Penilia avirostris (16.1%). The rate of cannibalism peaked in July, coinciding with a period of limited food availability. Additionally, the study revealed that fish eggs and larvae were infrequently found in the stomachs of M. leidyi. However, the presence of massive aggregations of M. leidyi may impact microzooplankton populations in late summer or autumn, potentially leading to competition with small pelagic fish.
Ključne besede: bioinvasion, cannibalism, comb jelly, competition, diet, Mediterranean Sea
Objavljeno v DiRROS: 10.04.2025; Ogledov: 706; Prenosov: 361
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4. Jellyfish modulate bacterial dynamic and community structureTinkara Tinta, Tjaša Kogovšek, Alenka Malej, Valentina Turk, 2012, izvirni znanstveni članek Povzetek: Jellyfish blooms have increased in coastal areas around the world and the outbreaks have become longer and more frequent over the past few decades. The Mediterranean Sea is among the heavily affected regions and the common bloom - forming taxa are scyphozoans Aurelia aurita s.l., Pelagia noctiluca, and Rhizostoma pulmo. Jellyfish have few natural predators, therefore their carcasses at the termination of a bloom represent an organic-rich substrate that supports rapid bacterial growth, and may have a large impact on the surrounding environment. The focus of this study was to explore whether jellyfish substrate have an impact on bacterial community phylotype selection. We conducted in situ jellyfish - enrichment experiment with three different jellyfish species. Bacterial dynamic together with nutrients were monitored to assess decaying jellyfish-bacteria dynamics. Our results show that jellyfish biomass is characterized by protein rich organic matter, which is highly bioavailable to ‘jellyfish - associated’ and ‘free - living’ bacteria, and triggers rapid shifts in bacterial population dynamics and composition. Based on 16S rRNA clone libraries and denaturing gradient gel electrophoresis (DGGE) analysis, we observed a rapid shift in community composition from unculturable Alphaproteobacteria to culturable species of Gammaproteobacteria and Flavobacteria. The results of sequence analyses of bacterial isolates and of total bacterial community determined by culture independent genetic analysis showed the dominance of the Pseudoalteromonadaceae and the Vibrionaceae families. Elevated levels of dissolved proteins, dissolved organic and inorganic nutrient release, bacterial abundance and carbon production as well as ammonium concentrations characterized the degradation process. The biochemical composition of jellyfish species may influence changes in the amount of accumulated dissolved organic and inorganic nutrients. Our results can contribute insights into possible changes in bacterial population dynamics and nutrient pathways following jellyfish blooms which have important implications for ecology of coastal waters.
Ključne besede: sea, medusae, research programmes, DGGE, Pelagia noctiluca, gel electrophoresis, oligotrophic waters, Adriatic Sea, jellyfish, gelatinous zooplankton, bacteria, flavobacteria
Objavljeno v DiRROS: 26.03.2025; Ogledov: 740; Prenosov: 573
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5. State of the art of the marine non-idigenous flora and fauna in SloveniaLovrenc Lipej, Borut Mavrič, Martina Orlando-Bonaca, Alenka Malej, 2012, izvirni znanstveni članek Povzetek: Authors provide the state of knowledge on marine non-indigenous species in waters off Slovenia. According to published records and authors unpublished data at least 15 non-indigenous species were up to date recorded in the Slovenian part of the Adriatic sea. Eleven species were considered as established and four species as casual. The vectors of introduction are various, comprising Lessepsian migration, mariculture and shipping. The majority of non-indigenous taxa were recorded in the mediolittoral belt and coastal lagoons. The low number of non-indigenous species so far recorded in the Slovenian part of the Adriatic sea could be explained by various factors. Among them, the most reasonable are the lack of scientific attention, the small proportion of Slovenian Sea and low winter temperatures, which represents a physiological barrier for the survival of newcomers. The number of recorded species is far from being satisfactory. Therefore, we expect that the list of non-indigenous species will be enlarged in the nearby future.
Ključne besede: biologija, vegetacija, ribe, favna, morje, Jadransko morje, biodiverziteta, Sredozemsko morje, neavtohtone vrste, Gambusia hoolbroki, Sardinella aurita, severni Jadran, obalno morje, morske alge, alohtone vrste, meridionalizacija, bioinvazije, varstvo narave, Tržaški zaliv, biološki kazalci
Objavljeno v DiRROS: 26.03.2025; Ogledov: 543; Prenosov: 352
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6. Is it possible to determine the economic impact of jellyfish outbreaks on fisheries? A Case Study - SloveniaBojan Nastav, Matevž Malej, Alenka Malej, Alenka Malej, 2013, izvirni znanstveni članek Povzetek: The interdependence between the economy and the environment is becoming a fact of increasing importance. Productive coastal areas have been recognised as one of the most valuable ecosystems from an ecological and socio-economic point of view. In this paper we focus on the massive presence of jellyfish in the northern Adriatic and their effect on the Slovenian economy. Our results indicate that high jellyfish abundance in 2004 resulted in a reduction of fish catch, value added, gross income, and employment in the fishing industry. Moreover, the government and the EU have acknowledged the impact of jellyfish on the fishing industry by allocating financial help to the fishermen involved. We attempted to assess other factors influencing the fishing industry but none were statistically significant. The input-output analysis has not revealed a significant impact on the entire Slovenian economy presumably due to the small contribution of the fishing industry to Slovenian GDP. Our work is a first attempt to relate ecological changes such as jellyfish outbreaks in the northern Adriatic to the wider economy and we suggest that such a methodology can be applied to other countries/regions and to other natural phenomena affecting the economy.
Ključne besede: morje, objavljeni prispevki na konferenci, morsko ribištvo, trajnostni razvoj, gospodarski aspekti, meduze, množično pojavljanje, distribucija, numerično modeliranje, klimatske spremembe, hipoteze, Pelagia noctiluca, Jadransko morje, gospodarske politike
Objavljeno v DiRROS: 26.03.2025; Ogledov: 829; Prenosov: 539
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7. Recurrent jellyfish blooms are a consequence of global oscillationsRobert H. Condon, Carlos M. Duarte, Kylie A. Pitt, Kelly L. Robinson, Cathy H. Lucas, Kelly R. Sutherland, Hermes Mianzan, Molly Bogeberg, Jennifer E. Purcell, Mary Beth Decker, Uye Shin-Ichi, Laurence P. Madin, Richard D. Brodeur, Steven Harold David Haddock, Alenka Malej, Gregory D. Parry, Elena Eriksen, Javier Quiñones, E. Marcelo Acha, Michel Harvey, James M. Arthur, William M. Graham, 2013, izvirni znanstveni članek Povzetek: A perceived recent increase in global jellyfish abundance has been portrayed as a symptom of degraded oceans. This perception is based primarily on a few case studies and anecdotal evidence, but a formal analysis of global temporal trends in jellyfish populations has been missing. Here, we analyze all available long-term datasets on changes in jellyfish abundance across multiple coastal stations, using linear and logistic mixed models and effect-size analysis to show that there is no robust evidence for a global increase in jellyfish. Although there has been a small linear increase in jellyfish since the 1970s, this trend was unsubstantiated by effect-size analysis that showed no difference in the proportion of increasing vs. decreasing jellyfish populations over all time periods examined. Rather, the strongest nonrandom trend indicated jellyfish populations undergo larger, worldwide oscillations with an approximate 20-y periodicity, including a rising phase during the 1990s that contributed to the perception of a global increase in jellyfish abundance. Sustained monitoring is required over the next decade to elucidate with statistical confidence whether the weak increasing linear trend in jellyfish after 1970 is an actual shift in the baseline or part of an oscillation. Irrespective of the nature of increase, given the potential damage posed by jellyfish blooms to fisheries, tourism, and other human industries, our findings foretell recurrent phases of rise and fall in jellyfish populations that society should be prepared to face.
Objavljeno v DiRROS: 26.03.2025; Ogledov: 593; Prenosov: 512
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8. Program spremljanja kakovosti morja in vnosov onesnaženja s kopnega v skladu z Barcelonsko konvencijo : letno poročilo 2010Valentina Turk, Oliver Bajt, Patricija Mozetič, Mateja Poje, Andreja Ramšak, Milijan Šiško, Alenka Malej, končno poročilo o rezultatih raziskav Povzetek: Slovenija kot članica programa Združenih narodov za okolje (UNEP) in podpisnica Konvencije o varovanju Sredozemskega morja pred onesnaženjem (Barcelonska konvencija) aktivno sodeluje v programu Sredozemskega akcijskega načrta (MAP-Mediterranean Action Plan). Program Spremljanja stanja okolja (MED POL program) izvajamo s finančno pomočjo Ministrstva za okolje in prostor R Slovenije, Agencije RS za okolje. Poročilo vključuje rezultate mikrobioloških analiz kakovosti kopaliških vod, fizikalno-kemične in biološke analize morske vode za oceno stopnje evtrofikacije, rezultate policikličnih in aromatskih ogljikovodikov, kadmija in živega srebra v sedimentu in morskih organizmih (školjkah), oceno vnosa s kopenskih točkovnih virov onesnaženja v morje in rezultate analiz biomonitoringa za oceno bioloških posledic onesnaženja na morskih organizmih.
Ključne besede: varstvo narave, kakovost morja, kontrola kakovosti, morje, onesnaževanje, ekologija morja, biomonitoring, monitoring, evtrofikacijski monitoring, indeks trofičnosti, evtrofizacija, trofični indeks, Tržaški zaliv, Barcelonska konvencija, Jadransko morje
Objavljeno v DiRROS: 16.09.2024; Ogledov: 1720; Prenosov: 1002
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9. Spremljanje kakovosti morja in vnosov onesnaženja s kopnega v skladu z Barcelonsko konvencijo v letu 2011 : poročilo 2011Valentina Turk, Oliver Bajt, Janja Francé, Mateja Poje, Andreja Ramšak, Milijan Šiško, Alenka Malej, končno poročilo o rezultatih raziskav Povzetek: Slovenija kot članica programa Združenih narodov za okolje (UNEP) in podpisnica Konvencije o varovanju Sredozemskega morja pred onesnaženjem (Barcelonska konvencija) aktivno sodeluje v programu Sredozemskega akcijskega načrta (MAP-Mediterranean Action Plan). Izvajanje projekta Spremljanje kakovosti morja in vnosov s kopnega v skladu z Barcelonsko konvencijo je omogočilo Ministrstva za okolje in prostor R Slovenije, Agencije RS za okolje. Poročilo vključuje rezultate mikrobioloških analiz kakovosti kopaliških voda, fizikalno-kemične in biološke analize morske vode za oceno stopnje evtrofikacije, rezultate policikličnih in aromatskih ogljikovodikov, kadmija in živega srebra v sedimentu in morskih organizmih (školjkah), oceno vnosa s kopenskih točkovnih virov onesnaženja v morje in rezultate analiz biomonitoringa za oceno bioloških posledic onesnaženja na morskih organizmih.
Ključne besede: varstvo narave, kakovost morja, kontrola kakovosti, morje, onesnaževanje, ekologija morja, monitoring, TRIX, indeks trofičnosti, evtrofizacija, trofični indeks, Tržaški zaliv, Barcelonska konvencija, Jadransko morje
Objavljeno v DiRROS: 16.09.2024; Ogledov: 2089; Prenosov: 1173
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10. Določanje dobrega okoljskega stanja. Poročilo za člen 9 Okvirne direktive o morski strategiji : zaključno poročilo 2012Martina Orlando-Bonaca, Lovrenc Lipej, Alenka Malej, Janja Francé, Branko Čermelj, Oliver Bajt, Nives Kovač, Borut Mavrič, Valentina Turk, Patricija Mozetič, Andreja Ramšak, Tjaša Kogovšek, Milijan Šiško, Vesna Flander-Putrle, Mateja Grego, Tinkara Tinta, Boris Petelin, Martin Vodopivec, Maja Jeromel, Urška Martinčič, Vlado Malačič, končno poročilo o rezultatih raziskav Povzetek: Deskriptor 1: Biotska raznovrstnost se ohranja. Kakovost in prisotnost habitatov ter razporeditev in številčnost vrst so v skladu s prevladujočimi fiziografskimi, geografskimi in podnebnimi pogoji.
»Presojo je treba opraviti na več ekoloških ravneh: na ravni ekosistemov, habitatov (vključno z njimi povezanimi združbami na nivoju biotopov) in vrst, ki so upoštevane v strukturi tega dela ob upoštevanju točke 2 dela A. Za nekatere vidike tega deskriptorja je potrebna dodatna znanstvena in tehnična podpora. Pri obravnavi širšega obsega deskriptorja je treba ob upoštevanju Priloge III k Direktivi 2008/56/ES določiti prioritete med elementi biotske raznovrstnosti (vrste, habitati in ekosistemi). To omogoča prepoznavanje tistih elementov in območij, kjer vplivi in grožnje nastajajo, poleg tega pa podpira opredelitev ustreznih kazalcev med izbranimi merili, primernimi za zadevna območja in elemente biotske raznovrstnosti. Obveznost regionalnega sodelovanja iz členov 5 in 6 Direktive 2008/56/ES je neposredno povezana z izbiro elementov biotske raznovrstnosti znotraj regij, podregij in pododdelkov, kjer je mogoče, pa tudi z vzpostavitvijo referenčnih razmer v skladu s Prilogo IV k Direktivi 2008/56/ES. Modeliranje z uporabo platforme geografskega informacijskega sistema je lahko uporabna podlaga za določanje območja razširjenosti elementov biotske raznovrstnosti ter človekovih dejavnosti in pritiskov zaradi teh dejavnosti, ob upoštevanju, da se vse mogoče zajete napake ustrezno ocenijo in opišejo ob uporabi rezultatov. Ti podatki so pogoj za ekosistemsko upravljanje človekovih dejavnosti in za razvoj s tem povezanih prostorskih orodij.«
Ključne besede: morje, obalno morje, onesnaževanje morja, plankton, hranilne snovi, ekološki parametri, onesnažila, onesnaževalci, biocenoze, okvirna direktiva o morski strategiji, poročila, onesnaženost, kvaliteta okolja, morska strategija, deskriptorji
Objavljeno v DiRROS: 16.09.2024; Ogledov: 1607; Prenosov: 1007
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