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Povzetek: Jellyfish are increasingly recognized as a significant contributor to marine organic matter (OM) on a global scale, with implications for ecosystem dynamics. While the role of jellyfish detritus in microbial nutrient cycling has been explored, the contribution of OM released by live jellyfish—primarily as mucus (hereinafter referred to as mucusassociated OM, or MAOM)—remains understudied. This study investigates the release of organic and inorganic nutrients through MAOM from live jellyfish and their effects on ambient microbial communities in the northern Adriatic Sea using a series of leaching and short-term microcosm experiments. Our results show that per gram of MAOM dry weight from the jellyfish Aurelia spp, approximatively 2 µmol of phosphate, 4 µmol of dissolved inorganic nitrogen, 18 µmol dissolved organic nitrogen, 134 µmol of dissolved organic carbon and 15 µmol of dissolved free amino acids can be released in the ambient seawater in 24 h. Almost half of the OM is released as dissolved OM (DOM), of which a substantial part is low molecular weight (<1 kDa) molecules. During the first 20 h, the DOM fraction of MAOM was rapidly consumed by the ambient microbial community without a corresponding increase in biomass, likely due to nitrogen limitation. In the subsequent 22 h, microbial growth accelerated to 0.19 ± 0.03 h−1 until phosphate became limiting, leading to a sharp decline in microbial production. Our metagenomics analysis revealed that the MAOM-degrading microbial community, dominated by Gammaproteobacteria opportunistic copiotrophs, exhibited increased functional capacity for nutrient assimilation and OM degradation, particularly in the transport and metabolism of amino acids (particularly glycine and taurine) and phosphorus. These traits mirror those found in detritus-degrading microbial communities, suggesting that jellyfish blooms promote the emergence of specialized microbial consortia with shared metabolic capabilities. Taken together, our findings highlight that live jellyfish, through the release of OM, play an active and previously underappreciated role in shaping ambient microbial community dynamics and nutrient fluxes in marine systems affected by jellyfish blooms.
Ključne besede: jellyfish, bacteria, biogeochemistry, metagenome
Objavljeno v DiRROS: 02.03.2026; Ogledov: 480; Prenosov: 48
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Ključne besede: research data, software, jellyfish, Mediterranean sea
Objavljeno v DiRROS: 27.10.2025; Ogledov: 441; Prenosov: 359
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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: 827; Prenosov: 524
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Povzetek: The analysis of historical data sets and the results obtained from field studies about the pressures exerted on coastal ecosystems in 18 sites of the Mediterranean and the Black Sea showed that : Inputs form Po and Danube rivers showed a high interannual variability. After an increase of eutrophication over the 70-80s, a decrease of nutrients inputs, especially of phosphate, was recorded since 1990. Positive impacts are seen on phytoplancton communities. In the vicinity of most coastal big cities the policy measures taken in order to reduce polluted water discharges show their effectiveness although some local issues still exist. Chemical contaminants levels decrease rapidly when the distance increase from point sources. However a large amount of coastal inputs is exported offshore. Attention should be paid to the fate and the impact of new emerging pollutants. At the basin scale, contaminant concentrations in biota show very different patterns depending on substances. For some substances, the biogeochemical background and the environmental conditions play a important role in the contamination of marine organisms. There is globally no evidence of neither degradation nor clear trends regarding seagrass meadows. The status of seagrass habitats is correlated to water quality. It can be concluded that human pressures have not affected seagrass meadows in a irreversible way. Seagrass habitats can recover (slowly) when pressures decrease. The rate of new introductions of Non Indigenous Species has been increasing at all coastal study areas after 2000. An increase of the Lessepsian species migration is seen, in link with climate change The analysis of 18 years of data about demersal fish communities showed a geographic variability in functional group (FG) biomass trends. Nearly half of the studied Mediterranean areas shows an increase of FG biomass. Changes respond mainly to nutrient inputs trends and to a lesser extent fishing pressure. Marine litter is increasing pressure on marine ecosystems. The majority of items were made of plastic often exceeding the global average of 75%. Some harmful effects on fauna are documented (birds, turtles…) but impact is poorly known. The lack of standardized methods for underwater noise measurements make difficult to assess the level of the pressure and the impact on marine ecosystems.
Ključne besede: sea, water directive, marine strategy framework directive, population dynamics, Gulf of Trieste, jellyfish, PERSEUS, environmental parameters
Objavljeno v DiRROS: 16.09.2024; Ogledov: 1100; Prenosov: 1084
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Povzetek: Wastewater treatment plants (WWTPs) are a focal point for the removal of microplastic (MP) particles before they are discharged into aquatic environments. WWTPs are capable of removing substantial quantities of larger MP particles but are inefficient in removing particles with any one dimension of less than 100 μm, with influents and effluents tending to have similar quantities of these smaller particles. As a single WWTP may release >100 billion MP particles annually, collectively WWTPs are significant contributors to the problem of MP pollution of global surface waters. Currently, there are no policies or regulations requiring the removal of MPs during wastewater treatment, but as concern about MP pollution grows, the potential for wastewater technologies to capture particles before they reach surface waters has begun to attract attention. There are promising technologies in various stages of development that may improve the removal of MP particles from wastewater. Better incentivization could speed up the research, development and adoption of innovative practices. This paper describes the current state of knowledge regarding MPs, wastewater and relevant policies that could influence the development and deployment of new technologies within WWTPs. We review existing technologies for capturing very small MP particles and examine new developments that may have the potential to overcome the shortcomings of existing methods. The types of collaborations needed to encourage and incentivize innovation within the wastewater sector are also discussed, specifically strong partnerships among scientific and engineering researchers, industry stakeholders, and policy decision makers.
Ključne besede: wastewater, microplastic, particle removal, innovation, policy, jellyfish mucus
Objavljeno v DiRROS: 06.08.2024; Ogledov: 1612; Prenosov: 1926
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