Sluttrapport - Artec pilot Dokumentasjon av vannkvalitet og fiskefysiologi i et pilotanlegg for resirkulering (Artec Pilot) og et gjennomstrømmingsanlegg

Sett under ett viser forsøkene at Resirkuleringssystemet (Artec Pilot) kan benyttes til kommersiell smoltproduksjon på lik linje med tradisjonelt gjennomstrømmingssystem. Ved optimal drift vil også fiskevelferden bli godt ivaretatt. Forskjellene i forsøksperiodene gjenspeiler hovedsakelig forskjellene mellom driftssystemene, hvor resirkulasjonssystemet inneholdt mer løst karbondioksid, nitrogenavfall, partikler og organisk materiale, spesielt i forsøk 1. Etter optimalisering av delprosesser og inkludering av CO2-lufting på karkanten ble nivåene av de nevnte parameterne betraktelig redusert. Dette har resultert i et velfungerende resirkuleringssystem som ivaretar fiskevelferden, og gir en jevn og god vannkvalitet.Artec Aqua A

Bacterioneuston Community Structure in the Southern Baltic Sea and Its Dependence on Meteorological Conditions▿†

The bacterial community in the sea surface microlayer (SML) (bacterioneuston) is exposed to unique physicochemical properties and stronger meteorological influences than the bacterial community in the underlying water (ULW) (bacterioplankton). Despite extensive research, however, the structuring factors of the bacterioneuston remain enigmatic. The aim of this study was to examine the effect of meteorological conditions on bacterioneuston and bacterioplankton community structures and to identify distinct, abundant, active bacterioneuston members. Nineteen bacterial assemblages from the SML and ULW of the southern Baltic Sea, sampled from 2006 to 2008, were compared. Single-strand conformation polymorphism (SSCP) fingerprints were analyzed to distinguish total (based on the 16S rRNA gene) and active (based on 16S rRNA) as well as nonattached and particle-attached bacterial assemblages. The nonattached communities of the SML and ULW were very similar overall (similarity: 47 to 99%; mean: 88%). As an exception, during low wind speeds and high radiation levels, the active bacterioneuston community increasingly differed from the active bacterioplankton community. In contrast, the particle-attached assemblages in the two compartments were generally less similar (similarity: 8 to 98%; mean: 62%), with a strong variability in the active communities that was solely related to wind speed. Both nonattached and particle-attached active members of the bacterioneuston, which were found exclusively in the SML, were related to environmental clones belonging to the Cyanobacteria, Bacteroidetes, and Alpha-, Beta-, and Gammaproteobacteria originally found in diverse habitats, but especially in water columns. These results suggest that bacterioneuston communities are strongly influenced by the ULW but that specific meteorological conditions favor the development of distinctive populations in the air-water interface