Development of a qPCR assay to detect and quantify ichthyotoxic flagellates along the Norwegian coast, and the first Norwegian record of Fibrocapsa japonica (Raphidophyceae)

Blooms of ichthyotoxic microalgae pose a great challenge to the aquaculture industry world-wide, and there is a need for fast and specific methods for their detection and quantification in monitoring programs. In this study, quantitative real-time PCR (qPCR) assays for the detection and enumeration of three ichthyotoxic flagellates: the dinoflagellate Karenia mikimotoi (Miyake & Kominami ex Oda) Hansen & Moestrup and the two raphidophytes Heterosigma akashiwo (Hada) Hada ex Hara & Chihara and Fibrocapsa japonica Toriumi & Takano were developed. Further, a previously published qPCR assay for the dinoflagellate Karlodinium veneficum (Ballantine) Larsen was used. Monthly samples collected for three years (Aug 2009–Jun 2012) in outer Oslofjorden, Norway were analysed, and the results compared with light microscopy cell counts. The results indicate a higher sensitivity and a lower detection limit (down to 1 cell L−1) for both qPCR assays. Qualitative and semi-quantitative results were further compared with those obtained by environmental 454 high throughput sequencing (HTS, metabarcoding) and scanning electron microscopy (SEM) examination from the same samplings. All four species were detected by qPCR and HTS and/or SEM in outer Oslofjorden (Aug 2009–Jun 2012); Karlodinium veneficum was present year-round, whereas Karenia mikimotoi, Heterosigma akashiwo and Fibrocapsa japonica appeared mainly during the autumn in all three years. This is the first observation of Fibrocapsa japonica in Norwegian coastal waters. This species has previously been recorded off the Swedish west coast and German Bight, which may suggest a northward dispersal

3D induction log modelling with integral equation method and domain decomposition preconditioning

The deployment of electromagnetic (EM) induction tools while drilling is one of the standard routines for assisting the geosteering decision-making process. The conductivity distribution obtained through the inversion of the EM induction log can provide important information about the geological structure around the borehole. To image the 3D geological structure in the subsurface, 3D inversion of the EM induction log is required. Because the inversion process is mainly dependent on forward modelling, the use of fast and accurate forward modelling is essential. In this paper, we present an improved version of the integral equation (IE) based modelling technique for general anisotropic media with domain decomposition preconditioning. The discretised IE after domain decomposition equals a fixed-point equation that is solved iteratively with either the block Gauss-Seidel or Jacobi preconditioning. Within each iteration, the inverse of the block matrix is computed using a Krylov subspace method instead of a direct solver. An additional reduction in computational time is obtained by using an adaptive relative residual stopping criterion in the iterative solver. Numerical experiments show a maximum reduction in computational time of 35 per cent compared to solving the full-domain IE with a conventional GMRES solver. Additionally, the reduction of memory requirement for covering a large area of the induction tool sensitivity enables acceleration with limited GPU memory. Hence, we conclude that the domain decomposition method is improving the efficiency of the IE method by reducing the computation time and memory requirement.Comment: This article is a manuscript submitted to Geophysical Journal Internationa

Field testing for toxic algae with a microarray: initial results from the MIDTAL project

One of the key tasks in the project MIDTAL (MIcroarrays for the Detection of Toxic ALgae) is to demonstrate the applicability of microarrays to monitor harmful algae across a broad range of ecological niches and toxic species responsible for harmful algal events. Water samples are collected from a series of sites used in national phytoplankton and biotoxin monitoring programmes across Europe. The samples are filtered; the rRNA is extracted, labelled with a fluorescent dye and applied to a microarray chip. The signal intensity from >120 probes previously spotted on the chip is measured and analysed. Preliminary results comparing microarray signal intensities with actual field counts are presented

Field testing for toxic algae with a microarray: initial results from the MIDTAL project

One of the key tasks in MIDTAL (MIcroarrays for the Detection of Toxic ALgae) is to demonstrate the applicability of microarrays to monitor harmful algae across a broad range of ecological niches and toxic species responsible for harmful algal events. Water samples are collected from a series of sites used in national phytoplankton and biotoxin monitoring across Europe. The samples are filtered; rRNA is extracted, labelled with a fluorescent dye and applied to a microarray chip. The signal intensity from >120 probes previously spotted on the chip is measured and analysed. Preliminary results comparing microarray signal intensities with actual field counts are presented.Versión del edito

The OSPAR Comprehensive Procedure for the Norwegian West Coast - Eutrophication Status

Årsliste 2007The Norwegian west coast from Lindesnes to Stad has been classified according to the OSPAR Common Procedure. Compared to the previous assessment in 2002, this classification is based on new data on nutrient load and more data on oxygen conditions, hard bottom fauna and flora (especially sugar kelp) as well as other data from a number of recipient studies. 21 areas have been classified. The two striking features are overall increased nutrient loads and lack of monitoring data. The existing data has been of very varying quality, but 4 Problem Areas, 14 Potential Problem Areas and 3 Non Problem Areas have been identified. The high number of Potential Problem Areas is caused by the combination of increased nutrient load and insufficient data for assessment of effects. There is a definite need for systematic monitoring with a long perspective, especially of Category II-III effects, and with focus on selected Potential Problem Areas.Statens Forurensningstilsyn

Undersøkelse av sjøresipienten utenfor Norwegian Crystallites AS på Drag i Tysfjord

Det er gjort undersøkelser om hvordan utslippet fra produksjon av høyren kvarts påvirker sjøresipienten utenfor Drag i Tysfjorden. Dette omfatter turbiditets- og hydrografimålinger, beregning og måling av pH og bruk av modeller til å beregne fortynning av utslippet, den vertikale stigning av det fortynnede avløpsvannet i vannsøylen og partikkel- og kjemikaliekonsentrasjoner i ulike avstander fra utslippet. Det er ikke sannsynlig at dagens utslipp av syre på 30 m representerer et miljøproblem. Utslipp av avløpsvannet har hyppige gjennomslag til overflaten på grunn av ferskvann i avløpsledningene og svak sjiktning i fjorden, men sjøvannets bufferkapasitet og gode fortynningsforhold gjør at pH-verdiene i resipienten avviker lite fra normalen. Utslipp av flotasjonskjemikalier og modellering av influensområde viser at konsentrasjoner som potensielt kan gi giftvirkninger begrenser seg til noen meter fra selve utslippet. På grunn av ufullstendig dokumentasjon av toksisitet overfor relevante marine organismer anbefales det at det gjøres en standard økotoks-test på avløpsvannet. I dette området vil det gjennomsnittlig avsettes ca. 4 mm avgang pr. år som er en beskjeden nedslamming av det naturlige bergartsmineralet kvarts. Vi kan vanskelig se at denne nedslammingen representerer et reelt miljøproblem

Common Procedure for Identification of the Eutrophication Status of Maritime Area of the Oslo and Paris Conventions. Report on the Eutrophication Status for the Norwegian Skagerrak Coast

The Norwegian Skagerrak coast has been classified according to the OSPAR Common Procedure. Compared to the previous assessment in 2002, this classification is based on new data on nutrient load, oxygen conditions, hardbottom fauna and flora (especially sugar kelp), harmful planktonic algae, as well as other data from a number of recipient studies. Fourteen areas have been studied and classified. The data has been of varying quality, but the overall classification of the coastline is Problem Area. One should note that the classification assumes that the decline of sugar kelp on the Norwegian Skagerrak coast to some extent is caused by eutrophication. For some areas this assumption is crucial for the classification. If future studies of the kelp disappearance prove otherwise, this classification should be revised