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Abstract: The purpose of this preliminary study was to define the vertical migration pattern in the dinoflagellate community in the shallow coastal sea. Migrations were followed in an area of mussel farming, through two 24-hour samplings, first during mixed and second during stratified water column conditions. Despite variable physical environment we were able to follow vertical migrations of some autotrophic dinoflagellate species in the period of stratified water column. The results also suggest that Heterocapsa sp. may preserve its vertical migration pattern also under mixed conditions. Migrations were observed also for Dinophysis sacculus that can cause DSP problems in the area.
Keywords: dinoflagellates, vertical migrations, eastern Adriatic coast, Adriatic Sea, dynamic environment, coastal sea, Adriatic
Published in DiRROS: 05.08.2024; Views: 46; Downloads: 18
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Abstract: The Indo-Pacific egg-carrying copepod Pseudodiaptomus marinus Sato, 1913 was recorded for the first time in the Port of Koper, Slovenia (Gulf of Trieste) in February 2015. This is the fourth finding of this species in the Mediterranean Sea, and the third for the Adriatic Sea. A rather high abundance of 73 ind. m-3 was recorded, which is considerably higher than previous findings in the Adriatic. Maritime transport is presumed to be the main cause of its introduction, primarily through ballast water release. Repeat sampling in May confirmed the presence of this copepod, indicating the possibility that the species has established a stable population in the Port of Koper.
Keywords: copepods, Adriatic Sea, mesozooplankton, ballast waters
Published in DiRROS: 29.07.2024; Views: 90; Downloads: 35
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Abstract: For mitigation of the effects of pollution, the media, policy makers and, in turn, the scientific community and industry each provide contributions through development of a sense of urgency, and with guidelines and solutions. For non-indigenous species (NIS) that can frequently have negative impacts on the native biota, this is often conveyed in an emotive way to the general public, who are typically keen to help and to get personally involved. This might be through organization of cleaning campaigns, influence on the media, or collaboration with scientists, to inform them of the local presence and abundance of NIS. Alternatively, they might proactively develop technological solutions themselves. To assess the current state of affairs, we reviewed the presence and effects of NIS in the Mediterranean Sea. As so often, any well-planned and successful activity is directly linked to financing, or a lack thereof, and this leads to sometimes untargeted and sporadic measures that are developed within a project or over a limited timeframe, without any sustainability measures. Therefore, we also assessed the activities and strategies that have been financed in this area of NIS mitigation. Based on this review of the presence and impact of NIS, and previous and ongoing activities, we propose a new paradigm to mitigate such pollution: the 8Rs model (i.e., Recognize, Reduce, Replace, Reuse, Recycle, Recover/Restore, Remove, and Regulate). This model extends from the more traditional 3Rs model (i.e., Reduce, Reuse, and Recycle) that is often used and promoted for innovative waste management strategies. Importantly, the 8Rs model can be applied sequentially, for either prevention of NIS introduction, or preparation of mitigation measures. The 8Rs model was constructed based on Mediterranean NIS, although we believe it can be applied to other sources of pollution and other geographic areas. Importantly, the 8Rs model represents a general framework to organize and categorize future pollution mitigation strategies. This approach is essential for development of any action plan to influence the administrative and financial decision makers who essentially enable these activities, and therefore who have important roles in the guarantee of sustainability of these actions, and the creation of innovative societies.
Keywords: non-indigenous species, pollution mitigation, pollution mitigation, 8Rs model, quadruple helix, Mediterranean Sea, citizen science, communication, sustainability
Published in DiRROS: 22.07.2024; Views: 102; Downloads: 108
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Abstract: Marine primary producers are highly sensitive to environmental deterioration caused by natural and human-induced stressors. Following the Water Framework Directive and the Marine Strategy Framework Directive requirements, the importance of using the different primary producers of the coastal marine ecosystem (pelagic: phytoplankton and benthic: macroalgae and angiosperms) as appropriate tools for an integrated assessment of the ecological status of the coastal environment has been recognized. However, the processes by which water column characteristics and phytobenthic indicators are linked have not been systematically studied. Based on a large dataset from three Mediterranean sub-basins (Adriatic, Ionian and Aegean Seas) with different trophic conditions, this study aims to explore the coupled responses of benthic and pelagic primary producers to eutrophication pressures on a large scale, focusing on the structural and functional traits of benthic macroalgal and angiosperm communities, and to investigate the key drivers among the different eutrophication-related pelagic indicators (such as nutrient and Chl-a concentrations, water transparency, etc.) that can force the benthic system indicators to low ecological quality levels. In addition to the effects of high nutrient loading on phytoplankton biomass, our results also show that increased nutrient concentrations in seawater have a similar effect on macroalgal communities. Indeed, increasing nutrient concentrations lead to increased coverage of opportunistic macroalgal species at the expense of canopy-forming species. Most structural traits of Posidonia oceanica (expressed either as individual metrics: shoot density, lower limit depth and lower limit type, or in the context of PREI index) show opposite trends to increasing levels of pressure indicators such as ammonium, nitrate, phosphate, Chl-a and light attenuation. Furthermore, our results highlight the regulating effect of light availability on the ecological status of seagrass meadows (Posidonia oceanica and Cymodocea nodosa). Increasing leaf length values of C. nodosa are closely associated with higher turbidity values linked to higher phytoplankton biomass (expressed as Chl-a). Overall, the coupling of pelagic and benthic primary producers showed consistent patterns across trophic gradients at the subregional scale.
Keywords: macroalgae, seagrasses, phytoplankton, eutrophication, Mediterranean Sea
Published in DiRROS: 17.07.2024; Views: 87; Downloads: 82
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Abstract: Diatoms are one of the most important phytoplankton groups in the world’s oceans. There are responsible for up to 40% of the photosynthetic activity in the Ocean, and they play an important role in the silicon and carbon cycles by decoupling carbon from atmospheric interactions through sinking and export. These processes are strongly influenced by the taxonomic composition of diatom assemblages. Traditionally, these have been assessed using microscopy, which in some cases is not reliable or reproducible. Next-generation sequencing enabled us to study diversity in a high-throughput manner and uncover new distribution patterns and diversity. However, phylogenetic markers used for this purpose, such as various 18S rDNA regions, are often insufficient because they cannot distinguish between some taxa. In this work, we demonstrate the performance of the chloroplast-encoded rbcL marker for metabarcoding marine diatoms compared to microscopy and 18S-V9 metabarcoding using a series of monthly samples from the Gulf of Trieste (GoT), northern Adriatic Sea. We demonstrate that rbcL is able to detect more taxa compared to 18S-V9 metabarcoding or microscopy, while the overall structure of the diatom assemblage was comparable to the other two methods with some variations, that were taxon dependent. In total, 6 new genera and 22 new diatom species for the study region were identified. We were able to spot misidentification of genera obtained with microscopy such as Pseudo-nitzschia galaxiae, which was mistaken for Cylindrotheca closterium, as well as genera that were completely overlooked, such as Minidiscus and several genera from the Cymatosiraceae family. Furthermore, on the example of two well-studied genera in the region, namely Chaetoceros and particularly Pseudo-nitzschia, we show how the rbcL method can be used to infer even deeper phylogenetic and ecologically significant differences at the species population level. Despite a very thorough community analysis obtained by rbcL the incompleteness of reference databases was still evident, and we shed light on possible improvements. Our work has further implications for studies dealing with taxa distribution and population structure, as well as carbon and silica flux models and networks.
Keywords: rbcL, metabarcoding, monitoring, diatoms, population genetics, Pseudo-nitzschia, Adriatic
Published in DiRROS: 12.07.2024; Views: 103; Downloads: 79
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