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Povzetek: The Malaspina-2010 circumnavigation expedition on board R/V Hesperides surveyed tropical and subtropical regions of the Atlantic, Indian and Pacific oceans between December 2010 and July 2011. This article examines the relationships between the distribution of chlorophyll a (Chl a), major inorganic nutrients and other hydrographic variables. A deep chlorophyll maximum (DCM) was found at most stations between 60 and 150 m depth; it occurred close to the level of 1% surface photosynthetically active radiation and was associated with the nitracline. There was a negative relationship between total Chl a at surface and the DCM depth, and between Chl a concentration at the DCM and DCM depth. In terms of Chl a concentration, picophytoplankton was the dominant size class at all sampled light intensities (surface, 20% of surface PAR and PAR at DCM), oceans and geoclimatic zones, except at some stations influenced by upwellings or divergences. Within the Chl a concentration ranges found in this study, the proportion of picophytoplankton increased with total Chl a, in contrast with some previous findings. Vertically integrated Chl a was positively correlated with surface Chl a, with similar slopes for the whole data set and for the different oceans and zones. In turn, surface Chl a and sea surface temperature showed a negative correlation for the Indian Ocean and the subtropical zone, a positive correlation for the Atlantic, and non-significant relationships for the remaining oceans and zones.
Ključne besede: Malaspina 2010, chlorophyll a, nitracline, deep chlorophyll maximum, phytoplankton size fractionation, Atlantic Ocean, Pacific Ocean, Indian Ocean, hydrobiology, marine biology
Objavljeno v DiRROS: 04.04.2025; Ogledov: 768; Prenosov: 485
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Povzetek: Trait-based ecology has recently gained increasing importance in phytoplankton research. In particular, the taxonomic and morphological traits, such as size and shape of phytoplankton cells, can help to unveil the ecological processes and their drivers in the pelagic domain. Our study aims to shed light on the trophodynamics of phytoplankton communities in a coastal ecosystem in the northern Adriatic Sea (Gulf of Trieste) using data on individual traits such as biomass, size and shape of phytoplankton taxa during a one-year study. The phytoplankton parameters were investigated at the levels of the whole community, groups, and individual cells, analysing also the probability distributions of biomass and size of the latter level. The results showed good agreement between abundance and biomass data, as well as individual size and biomass with differences partly explained by cell shapes. We have emphasized the role of the local freshwater source in bottom-up control, alternating with top-down control of phytoplankton dynamics through taxonomic and morphological diversity. The predominant bimodal and non-power law distribution, especially during and around the biomass peaks, confirmed the importance of nano- and microphytoplankton size classes and the role of blooms in destabilizing the trophic webs. We suggest that the analyses of distribution types of individual cell size and biomass can be appropriate to spot ecological processes driving to unconstrained phytoplankton proliferation or to periods of trophic web stability.
Ključne besede: phytoplankton, biomass, taxonomic traits, morphological traits, Northern Adriatic, trophodynamics, pelagic domain
Objavljeno v DiRROS: 08.10.2024; Ogledov: 1101; Prenosov: 1071
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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: 1610; Prenosov: 1007
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Povzetek: Morske trave niso alge, temveč spadajo med cvetnice. Od okoli 60 vrst, ki obstajajo na svetu, samo 4 izvorno uspevajo v Evropi – in vse najdemo tudi v slovenskem morju. To so: prava morska trava (Zostera marina), mala morska trava (Zostera noltii), kolenčasta cimodoceja (Cymodocea nodosa) in pozejdonka (Posidonia oceanica). Za vse so značilni tanki, ozki in dolgi listi. Pri nas tvori največje in najgloblje travnike kolenčasta cimodoceja (Cymodocea nodosa). Prisotnost morske trave je pokazatelj dobre kakovosti obalnega morja, travniki pa so pomemben habitat za številne organizme.
Ključne besede: hidrobiologija, morja, nevarnosti, zmotna prepričanja
Objavljeno v DiRROS: 04.09.2024; Ogledov: 1045; Prenosov: 474
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Povzetek: Marine Non-Indigenous Species (NIS) are animals and plants introduced accidently or deliberately into the European seas, originating from other seas of the globe. About 800 marine non-indigenous species (NIS) currently occur in the European Union national marine waters, several of which have negative impacts on marine ecosystem services and biodiversity. Under the Marine Strategy Framework Directive (MSFD) Descriptor 2 (D2), EU Member States (MSs) need to consider NIS in their marine management strategies. The Descriptor D2 includes one primary criterion (D2C1: new NIS introductions), and two secondary criteria (D2C2 and D2C3). The D2 implementation is characterized by a number of issues and uncertainties which can be applicable to the Descriptor level (e.g. geographical unit of assessment, assessment period, phytoplanktonic, parasitic, oligohaline NIS, etc.), to the primary criterion D2C1 level (e.g. threshold values, cryptogenic, questionable species, etc), and to the secondary criteria D2C2 and D2C3. The current report tackles these issues and provides practical recommendations aiming at a smoother and more efficient implementation of D2 and its criteria at EU level. They constitute a solid operational output which can result in more comparable D2 assessments among MSs and MSFD regions/subregions. When it comes to the policy-side, the current report calls for a number of different categories of NIS to be reported in D2 assessments, pointing the need for the species to be labelled/categorised appropriately in the MSFD reporting by the MSs. These suggestions are proposed to be communicated to the MSFD Working Group of Good Environmental Status (GES) and subsequently to the Marine Strategy Coordination Group (MSCG) of MSFD. Moreover, they can serve as an input for revising the Art. 8 Guidelines.
Objavljeno v DiRROS: 02.09.2024; Ogledov: 1032; Prenosov: 846
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