Wenche Eikrem

Norwegian Institute for Water Research | NIVA

Understanding the long-term response of key marine phytoplankton species to ongoing global changes is pivotal in determining how oceanic community composition will respond over the coming decades. To better understand the impact of ocean acidification and warming, we acclimated two strains of Skeletonema marinoi isolated from natural communities to...

Egge E, Deininger A, Bekkby T, Eikrem W, Mengeot C, Frigstad H, Moyano M, Kvile KØ, Baur AK, Tobiesen A, Harvey TE, Saesin P. 2023. Økokyst - DP Norskehavet sør, Årsrapport 2022. NIVA-rapport 7898, Miljødirektoratet rapport 2595. ISBN: 978-82-577-7634-3

Time series are essential for studying the long-term effects of human impact and climatic changes on the natural environment. Although data exist, no long-term phytoplankton dataset for the Norwegian coastal area has been compiled and made publicly available in a standardised format. Here we report on a compilation of phytoplankton data from inner...

Changes in phytoplankton abundance and biomass during the period 1933–2020 were examined by statistical modeling using data from the Inner Oslofjorden phytoplankton database. The phytoplankton abundances increased with eutrophication from 1930s to 1970s, but with the implementation of sewage cleaning measures and a resulting reduction in nutrient r...

We report the first ever nation-wide study of the occurrence of non-indigenous species in Danish harbours. The sampling was carried out using both conventional and biomolecular methods (eDNA). In total, 16 harbours were covered – Esbjerg and Aarhus, the two largest harbours in Denmark, with intensive sampling and 14 harbours with a reduced programm...

A bloom of the fish-killing haptophyte Chrysochromulina leadbeateri in northern Norway during May and June 2019 was the most harmful algal event ever recorded in the region, causing massive mortalities of farmed salmon. Accordingly, oceanographic and biodiversity aspects of the bloom were studied in unprecedented detail, based on metabarcoding and...

Overvåkingsprogrammet "Økosystemovervåking i Kystvann – Økokyst" har til hensikt å overvåke miljøtilstanden langs norskekysten i henhold til vannforskriften. Økokyst delprogram Norskehavet Sør dekker kyststrekningen fra Ulsteinvik i sør til Helgeland i nord. Av de 11 vannforekomster som kunne klassifiseres, fikk 1 “svært god” tilstand, 7 «god» tils...

The phylogenetic diversity of Ochrophyta, a diverse and ecologically important radiation of algae, is still incompletely understood even at the level of the principal lineages. One taxon that has eluded simple classification is the marine flagellate genus Olisthodiscus. We investigated O. luteus K‐0444, and documented its morphological and genetic...

The monitoring program "Ecosystem Monitoring in Coastal Water - ØKOKYST" aims at monitoring the environmental status in selected areas along the Norwegian coast according to vannforskriften (the Water Framework Directive). Subprogram Norskehavet Sør I includes Ulsteinvik and Geirangerfjorden. All the biological quality elements obtained at least “g...

The monitoring program "Ecosystem Monitoring in Coastal Water - ØKOKYST" aims at monitoring the environmental status in selected areas along the Norwegian coast according to vannforskriften (the Water Framework Directive). Subprogram Skagerrak includes 14 water bodies within the area of outer Oslofjord and the Grenlandfjords. The overall condition...

Datareport from the FerryBox monitoring of Inner Oslofjord 2019 for "Fagrådetfor vann- og avløpsteknisk samarbeid i indre Oslofjord"

Datareport from the FerryBox monitoring of Inner Oslofjord 2018 for "Fagrådetfor vann- og avløpsteknisk samarbeid i indre Oslofjord"

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Members of the class Mamiellophyceae comprise species that can dominate picophytoplankton diversity in polar waters. Yet polar species are often morphologically indistinguishable from temperate species, although clearly separated by molecular features. Here we examine four Mamiellophyceae strains from the Canadian Arctic. The 18S rRNA and Internal...

Members of the class Mamiellophyceae comprise species that can dominate picophytoplankton diversity in polar waters. Yet polar species are often morphologically indistinguishable from temperate species, although clearly separated by molecular features. Here we examine four Mamiellophyceae strains from the Canadian Arctic. The 18S rRNA and Internal...

Diatoms constitute a diverse lineage of unicellular organisms abundant and ecologically important in aquatic ecosystems. Compared to other protists, their biology and taxonomy are well-studied, offering the opportunity to combine traditional approaches and new technologies. We examined a dataset of diatom 18S rRNA- and rDNA- (V4 region) reads from...

Protist community composition and seasonal dynamics are of major importance for the production of higher trophic levels, such as zooplankton and fish. Our aim was to reveal how the protist community in the Skagerrak changes through the seasons by combining high‐throughput sequencing and microscopy of plankton collected monthly over two years. The V...

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 dinoflagell...

Prasinophytes are a paraphyletic group of nine lineages of green microalgae that are currently classified either at the class or order level or as clades without formal taxonomic description. Prasinophyte clade VII comprises picoplanktonic algae that are important components of marine phytoplankton communities, particularly in moderately oligotroph...

Haptophyta are predominantly planktonic and phototrophic organisms that have their main distribution in marine environments worldwide. They are a major component of the microbial ecosystem, some form massive blooms and some are toxic. Haptophytes are significant players in the global carbonate cycle through photosynthesis and calcification. They ar...

Haptophyta are predominantly planktonic and phototrophic organisms that have their main distribution in marine environments worldwide. They are a major component of the microbial ecosystem, some form massive blooms and some are toxic. Haptophytes are significant players in the global carbonate cycle through photosynthesis and calcification. They ar...

Haptophyta are predominantly planktonic and phototrophic organisms that have their main distribution in marine environments worldwide. They are a major component of the microbial ecosystem, some form massive blooms and some are toxic. Haptophytes are significant players in the global carbonate cycle through photosynthesis and calcification. They ar...

Marine protist diversity inventories have largely focused on planktonic environments, while benthic protists have received relatively little attention. We therefore hypothesize that current diversity surveys have only skimmed the surface of protist diversity in marine sediments, which may harbour greater diversity than planktonic environments. We t...

Marine protist diversity inventories have largely focused on planktonic environments, while benthic protists have received relatively little attention. We therefore hypothesize that current diversity surveys have only skimmed the surface of protist diversity in marine sediments, which may harbor greater diversity than planktonic environments. We te...

Heterosigma akashiwo is one of the smallest raphidophytes and is known for its ability to form dense, fishkilling blooms. In many parts of the world, H. akashiwo is a permanent resident of the algal community, and blooms have caused extensive financial losses for the aquaculture industry. Different aspects of its biology have been the focus of nume...

Microalgae in the division Haptophyta play key roles in the marine ecosystem and in global biogeochemical processes. Despite their ecological importance, knowledge on seasonal dynamics, community composition and abundance at the species level is limited due to their small cell size and few morphological features visible under the light microscope....

We have isolated three novel lytic dsDNA-viruses from Raunefjorden (Norway) that are putative members of the Mimiviridae family, namely Haptolina ericina virus RF02 (HeV RF02), Prymnesium kappa virus RF01 (PkV RF01), and Prymnesium kappa virus RF02 (PkV RF02). Each of the novel haptophyte viruses challenges the common conceptions of algal viruses w...

A propagule experiment was designed to investigate the effects of different food types and varying sediment depths on the survival and growth of upper-bathyal benthic foraminifera, collected from surface-sediment cores in Oslofjord, Norway. Sediment that passed through a 53-μm sieve was used in the experiment. Any foraminifera >63 μm at the end of...

Microalgae in the division Haptophyta may be difficult to identify to species by microscopy because they are small and fragile. Here we used high-throughput sequencing to explore the diversity of haptophytes in outer Oslofjorden, Skagerrak, and supplemented this with electron microscopy. Nano- and picoplanktonic subsurface samples were collected mo...

GenBank staff is unable to verify sequence and/or annotation provided by the submitter. ##Assembly-Data-START## Assembly Method :: ABySS v. 1.3.6 Sequencing Technology :: SOLiD ##Assembly-Data-END##

##Assembly-Data-START## Assembly Method :: ABySS v. 1.3.6 Sequencing Technology :: SOLiD ##Assembly-Data-END##

##Assembly-Data-START## Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##

##Assembly-Data-START## Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##

List of probes represented on the MDITAL microarray generation 2.5. Probe sequences are not provided because the microarray is patent pending. Probes on generation 3.3 arrays have the same specificity and sequence, but have the suffix “_dT” was added to the probe name

Estimations of detection limits for selected probes as determined by different partners of the MIDTAL project and published by Kegel et al. (2012) with modifications according to Edvardsen et al. (2012) for Dinophysis spp.

Telonema is a genus of heterotrophic flagellates with two flagella that occurs in marine environments. Although some aspects of the morphology and ultrastructure of Telonema have been reported in previous studies, several characters have been described incompletely or not at all. In the present study, we identify and describe several of these chara...

Monitoring of marine microalgae is important to predict and manage harmful algal blooms. Microarray Detection of Toxic ALgae (MIDTAL) is an FP7-funded EU project aiming to establish a multi-species microarray as a tool to aid monitoring agencies. We tested the suitability of different prototype versions of the MIDTAL microarray for the monthly moni...

The annual cycle of the diatom genus Pseudo-nitzschia was examined in Outer Oslofjorden, Norway. Vertical net tows (2 5-0 m depth) and seawater samples (1m depth) were collected monthly for one year (June 2009 -June 2010). The diversity of Pseudo-nitzschia species were recorded from live and preserved material with light microscopy and from acid cl...

A culture of Thaumatomastix was isolated from a sediment sample collected in Oslofjorden and established as a monospecific strain (UIO286). Based on this culture, light and transmission electron microscopy and phylogenetic analyses were carried out. Thaumatomastix species are confined within the order Thaumatomonadida of the class Imbricatea and ph...

Nucleotide sequences of the nuclear-encoded small subunit (18S rDNA) and partial large subunit (28S rDNA) ribosomal DNA were determined in 30 different species of the haptophyte genera Prymnesium, Chrysocampanula, Chrysochromulina, Imantonia and Platychrysis, all belonging to the order Prymnesiales. Phylogenies based on these and other available ha...

Blooms of Prymnesium causing mortality in farmed fish have been registered in fjords belonging to the Sandsfjord system, southwestern Norway, annually since 1989. These blooms consist of two closely related species, P. patelliferum and P. parvum. Cultures of the former species were established from field samples, and their identity was confirmed by...

During the BIOSOPE cruise in the South-East Pacific Ocean in 2004, several unidentified strains of prasinophytes were isolated into culture. Of these, nine strains composed a group for which the partial 18S rRNA gene sequence was related to Prasinoderma coloniale. The ultrastructure, morphology, division process, pigment composition, genome size an...

In Norwegian waters, Prymnesium parvum has been reported from Oslofjorden in the south to Spitzbergen in the north. However, blooms of P. parvum have only been reported from the Sandsfjorden system in Ryfylke, Western Norway where the salinity of the permanent brackish layer (2-5 m) typically is in the range of 4-7 psu during the summer months. The...

Verrucophora farcimen is renamed Pseudochattonella farcimen, and V. farcimen should be regarded as a synonym of P. farcimen for reasons of priority. The genus name Verrucophora Eikrem, Edvardsen et Throndsen is based on a new species Verrucophora farcimen Eikrem, Edvardsen et Throndsen, but is also including the former Chattonella veruculosa; Y. Ha...

A marine haptophyte flagellate, Chrysochromulina palpebralis sp. nov., is described from cultures originating from the Nervió n River estuary in the Cantabrian Sea, northern Spain. In addition, cultures of similar organisms originating from Japanese and South African waters have been studied. Cells of C. palpebralis had an ovoid shape with an anter...

Picoeukaryotes are a taxonomically diverse group of organisms less than 2 micrometers in diameter. Photosynthetic marine picoeukaryotes in the genus Micromonas thrive in ecosystems ranging from tropical to polar and could serve as sentinel organisms for biogeochemical fluxes of modern oceans during climate change. These broadly distributed primary...