Preliminarna studija o vertikalnim migracijama dinoflagelata u dinamičnom obalnom moru (Tršćanski zaljev, sjeverni Jadran)

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.Svrha ove preliminarne studije je definirati obrasce vertikalnih migracija zajednice dinoflagelata u plitkom obalnom moru. Migracije su praćene na području uzgoja dagnji, kroz dva 24-satna uzorkovanja, prvo za vrijeme pomiješanih i drugo za vrijeme stratificiranih uvjeta vodenog stupca. Unatoč promjenjivom fizičkom okolišu bili smo u mogućnosti slijediti vertikalne migracije nekih autotrofnih vrsta dinoflagelata u razdoblju stratificiranog vodenog stupca. Rezultati također sugeriraju da Heterocapsa sp. može očuvati obrazac svoje vertikalne migracije čak i u pomiješanim uvjetima. Migracije su promatrane i za vrstu Dinophysis sacculus koja može uzrokovati dijaretičko trovanje školjkama (DSP) na tom području

The most suitable time and depth to sample Cymodocea nodosa (Ucria) Ascherson meadows in the shallow coastal area. Experiences from the northern Adriatic Sea

The Lesser Neptune grass, Cymodocea nodosa, is the most common seagrass species in shallow sheltered to semi-exposed sites along the Mediterranean soft bottom. The MediSkew index was recently developed as an improvement of the CymSkew index, in order to assess the status of C. nodosa meadows correctly in view of the implementation of three European Directives. The index takes into account the length of the photosynthetic part of C. nodosa leaves, which increases from the less degraded meadow to the most degraded meadow. To adequately assess temporal and spatial trends in the status of C. nodosa meadows, including estimates of the effects of natural disturbances within marine protected areas, the MediSkew index was applied to new samples collected at 3 m and at 6 m of depth, during two months (in July and in September). The analyses are discussed in view of monitoring and conservation of C. nodosa meadows. According to the results of this study, the monitoring programme in the northern Adriatic Sea should be conducted in July, with the collection of samples at 3 m of depth. The presented sampling and assessing methodology proved to be time- and cost-effective for the evaluation of the status of C. nodosa meadows and of human-induced pressures

Najprikladnije vrijeme i dubina za uzorkovanje livada morske cvjetnice Cymodocea nodosa (Ucria) Ascherson, u plitkom obalnom području. Iskustva iz sjevernog Jadrana

The Lesser Neptune grass, Cymodocea nodosa, is the most common seagrass species in shallow sheltered to semi-exposed sites along the Mediterranean soft bottom. The MediSkew index was recently developed as an improvement of the CymSkew index, in order to assess the status of C. nodosa meadows correctly in view of the implementation of three European Directives. The index takes into account the length of the photosynthetic part of C. nodosa leaves, which increases from the less degraded meadow to the most degraded meadow. To adequately assess temporal and spatial trends in the status of C. nodosa meadows, including estimates of the effects of natural disturbances within marine protected areas, the MediSkew index was applied to new samples collected at 3 m and at 6 m of depth, during two months (in July and in September). The analyses are discussed in view of monitoring and conservation of C. nodosa meadows. According to the results of this study, the monitoring programme in the northern Adriatic Sea should be conducted in July, with the collection of samples at 3 m of depth. The presented sampling and assessing methodology proved to be time- and cost-effective for the evaluation of the status of C. nodosa meadows and of human-induced pressures.Čvorasta morska resa, Cymodocea nodosa, najučestalija je vrsta morske cvjetnice u plitkim zaklonjenim i poluzaklonjenim uvalama duž mediteranskog mekog dna. MediSkew indeks je nedavno razvijen kao poboljšanje indeksa CymSkew u cilju ispravne procjene stanja livada vrste C. nodosa u skladu s provedbom triju europskih direktiva. Indeks u obzir uzima duljinu foto sintetskog dijela lišća C. nodosa, koji se povećava od manje do najviše degradirane livade. Kako bi se na odgovarajući način procijenili vremenski i prostorni trendovi stanja livada vrste C. nodosa, uključujući procjene učinaka prirodnih poremećaja unutar zaštićenih morskih područja, MediSkew indeks primijenjen je na nove uzorke prikupljene na 3m dubine i na 6m dubine, tijekom srpnja i rujna. Analize su rađene s obzirom na praćenje i očuvanje livada vrsteC. nodosa. Prema rezultatima ovog istraživanja, program praćenja u sjevernom Jadranu trebao bi biti proveden u srpnju, a uzorci bi se prikupljali na 3m dubine. Prikazana metodologija uzorkovanja i procjenjivanja pokazala se vremenski i troškovno učinkovita za procjenu stanja livada vrste C. nodosa i ljudskog utjecaja na njih

Additional record of the non-indigenous copepod Pseudodiaptomus marinus (Sato, 1913) in the Adriatic Sea

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

Evaluation of the rbcL marker for metabarcoding of marine diatoms and inference of population structure of selected genera

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

New tools and recommendations for a better management of harmful algal blooms under the European Marine Strategy Framework Directive

23 pages, 2 figures, supplementary material https://www.frontiersin.org/articles/10.3389/.2023.1298800/full#supplementary-materialMarine harmful algal blooms (HABs), caused by various aquatic microalgae, pose significant risks to ecosystems, some socio-economic activities and human health. Traditionally managed as a public health issue through reactive control measures such as beach closures, seafood trade bans or closure of mollusc production areas, the multifaceted linkages of HABs with environmental and socio-economic factors require more comprehensive ecosystem-based management approach tools to support policies. This study promotes a coordinated understanding and implementation of HAB assessment and management under the Marine Strategy Framework Directive (MSFD), targeting the achievement of Good Environmental Status (GES) in European marine waters. We introduce two novel tools: GES4HABs (GES for HABs) decision tree, and MAMBO (environMental mAtrix for the Management of BlOoms), a decision support matrix. These tools aim to streamline HABs reporting and prioritize resource allocation and management interventions. The GES4HABs decision tree defines a sequence of decision steps to identify HAB management strategies according to their state (evaluated against predefined baselines) and causes (anthropic or natural). MAMBO is proposed to address different HABs and their interaction with human and environmental pressures. The matrix utilizes two axes: natural trophic status and level of human influence, capturing major aspects such as nutrient supply. While acknowledging the limitations of this simplified framework, MAMBO categorizes marine regions into quadrants of varying management viability. Regions with high human influence and eutrophic conditions are identified as most suitable for effective management intervention, whereas regions with minimal or mixed human influence are deemed less amenable to active management. In addition, we explore and describe various indicators, monitoring methods and initiatives that may be relevant to support assessments of HAB status and associated pressures and impacts in the MSFD reporting. Finally, we provide some recommendations to promote the consideration of HABs in ecosystem-based management strategies, intensify efforts for harmonizing and defining best practices of analysis, monitoring and assessment methodologies, and foster international and cross-sectoral coordination to optimize resources, efforts and rolesThis manuscript is a result of the joint activity of two projects funded by the European Union, under the Horizon Europe program: GES4SEAS (Achieving Good Environmental Status for maintaining ecosystem services, by assessing integrated impacts of cumulative pressures; grant agreement no. 101059877; www.ges4seas.eu) and ACTNOW (Advancing understanding of cumulative impacts on European marine biodiversity, ecosystem functions and services for human wellbeing, grant agreement No. 101060072). JF was financially supported by the Slovenian Research and Innovation Agency (research core funding no. P1-0237). This work by EG, NS, AR, and JC acknowledges the ‘Severo Ochoa Centre of Excellence' accreditation (CEX2019-000928-S) funded by AEI 10.13039/501100011033 to the Institut de Ciencies del Mar, CSICPeer reviewe