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Povzetek: Ammonia-oxidizing Archaea (AOA) are ubiquitous throughout the oceanic water column; however, our knowledge on their physiological and ecological diversity in different oceanic regions is rather limited. Here, we report the cultivation and characterization of two novel Nitrosopumilus strains, originating from coastal surface waters of the Northern Adriatic Sea. The combined physiological and genomic information revealed that each strain exhibits different metabolic and functional traits, potentially reflecting contrasting life modes. Strain NF5 contains many chemotaxis-related genes and is able to express archaella, suggesting that it can sense and actively seek favorable microenvironments such as nutrient-rich particles. In contrast, strain D3C is non-motile and shows higher versatility in substrate utilization, being able to use urea as an alternative substrate in addition to ammonia. Furthermore, it encodes a divergent, second copy of the AmoB subunit of the key enzyme ammonia monooxygenase, which might have an additional catalytic function and suggests further metabolic versatility. However, the role of this gene requires further investigation. Our results provide evidence for functional diversity and metabolic versatility among phylogenetically closely related thaumarchaeal strains, and point toward adaptations to free-living versus particle-associated life styles and possible niche differentiation among AOA in marine ecosystems.
Ključne besede: seawater, ammonia oxidation, bacteria, picoplankton, Northern Adriatic Sea, genomic information
Objavljeno v DiRROS: 19.03.2025; Ogledov: 230; Prenosov: 372
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Povzetek: A specially constructed enclosure in the lagoon environment (Lagoon of Strunjan, Gulf of Trieste, northern Adriatic Sea) received sewage daily while another was kept clean and used as a reference. Nutrients and community production changes were monitored approximately bimonthly over a year. Nutrients introduced by the sewage discharges and diluted by tides were immobilized by enhanced community production, in particular benthic macroalgae. The dead organic matter afterwards settled and decomposed producing anoxic conditions and high levels of dissolved and suspended organic nutrients in the water and total nitrogen in the sediments. The daily mean gross community production showed no quantitative differences between the two enclosures during the study. Differences arose in the temporal succession of the studied events. An intensive nutrient recycling emerged from this study.
Ključne besede: carbon, lagoons, nutrients, northern Adriatic, oxygen, production (biology)
Objavljeno v DiRROS: 19.03.2025; Ogledov: 193; Prenosov: 211
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Povzetek: Cryptobenthic fish are small benthic fish species that normally live in various hiding places. Due to their large numbers, they are very important for energy transfer to higher trophic levels. However, due to their small size and hidden lifestyle, knowledge about them and their ecology, including their diet, is still limited. Using a non-destructive method based on faecal pellets, we investigated the diet of three clingfish species, Lepadogaster lepadogaster, L. candolii, and Apletodon incognitus, in the shallow northern Adriatic Sea. To better understand the results, we studied the fauna of potential prey in the habitats of the fish studied and also took fish specimens to observe their behaviour in the laboratory. The three species feed predominantly on crustaceans, particularly amphipods, copepods, and decapods. The proportion of the different taxa in the diet depends on the species of clingfish, the size of the specimens, and the size of the prey. In addition, the behaviour of the fish, the home range of the specimens, and the availability of food played an important role. The presence of certain crustacean groups in the environment also determines the occurrence of clingfish of different species and sizes.
Ključne besede: cryptobenthic fish, clingfish species, diet, diet habits, non-destructive method, faecal pellets, crustaceans, northern Adriatic Sea
Objavljeno v DiRROS: 03.10.2024; Ogledov: 546; Prenosov: 245
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Povzetek: The Canestrini’s goby is a small goby endemic to the Adriatic basin, inhabiting brackish and fresh waters. The species is threatened by habitat destruction and pollution. For this reason, the goby is protected in part of its range, while its conservation status in other areas is not yet established. The detailed biogeography of the species should be known so that appropriate conservation measures can be taken. Despite extensive sampling of fish fauna in coastal wetlands, this species has not yet been detected in Slovenia. In this study, the first record of Ninnigobius canestrinii (Ninni, 1883) in Slovenian waters is reported along with a comprehensive review of documented records of the species.
Ključne besede: Gobiidae, endemic goby, endangered species, habitat endangerment, habitat destruction, biogeography, northern Adriatic basin, Slovenia
Objavljeno v DiRROS: 06.08.2024; Ogledov: 620; Prenosov: 325
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Povzetek: Background. The blackspotted smooth-hound, Mustelus punctulatus Risso, 1826, has been regularly caught in the northern Adriatic Sea, although a decreasing trend in its catches was observed off the coast of Slovenia within the last decade The knowledge of feeding behaviour of elasmobranch fish species, through understanding of the local food web structure, contributes to better and more efficient fish stock assessment and ecosystem modelling. This study is a first step in determining the prey consumption by the blackspotted smooth-hound in the area. Materials and methods. A total of 151 blackspotted smooth-hounds caught by commercial fishermen in the Gulf of Trieste from 4 June 2002 to 4 June 2003 were examined in this study. The stomach contents were removed, sorted and identified to the lowest possible taxon using identification keys. Preys were counted and weighed. Frequency of occurrence (F%), relative abundance (N%), the percentage by weight (W%), the Index of Relative Importance (IRI), and its standardized value (%IRI) were calculated following standard procedures. For comparing the diet between four different size classes we calculate average prey weight, dietary diversity, average meal, and trophic level for each size class. Results. A total 130 fish stomachs contained prey items. Crustaceans were the most important prey items (IRI% = 56.14), whereas cephalopods were the second mostly preyed animals (IRI% = 20.2). Teleost fish and bivalves were also found in the stomachs. The most important prey species was Solecurtus strigillatus. Larger sharks consumed larger preys. Male and female sharks consumed similar food. Juvenile individuals consumed predominantly crustaceans, while cephalopods were more important in the diet of adult individuals. The calculated trophic index (TROPH) of M. punctulatus from northern Adriatic Sea was 3.7, showing that it is a highly carnivorous species. Conclusion. This study is a first step in determining prey consumption by Mustelus punctulatus which is, despite the fact that is still common in the area, a rather poorly known species. For elucidating the role of benthic sharks in the study area the further step would be to study the diet of a closely related common smooth-hound M. mustelus.
Ključne besede: fishes, ichthyology, Adriatic sea, Triakidae, Mustelus punctulatus, trophic level, northern Adriatic, elasmobranchii, diversity, Mustelus, Mediterranean, feeding, Adriatic Sea
Objavljeno v DiRROS: 05.08.2024; Ogledov: 640; Prenosov: 455
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