maritmbj

• d'Auriac, Marc Anglès; Ørberg, Sarah Bachmann; Borgersen, Gunhild; Gundersen, Hege; Matsson, Sanna & Bjorbækmo, Marit Frederikke Markussen [Show all 10 contributors for this article] (2026). Tracing species-specific kelp eDNA in marine sediments for blue carbon assessment along the Norwegian Coast. Frontiers in Marine Science. 13. doi: 10.3389/fmars.2026.1784926. Full text in Research Archive Show summary

  Terrestrial primary production is acknowledged as a major contributor to atmospheric carbon transformation and storage. In contrast, marine primary production, especially the contribution from kelp forests, remains less studied and accounted for. To facilitate studies on marine kelp and organic carbon, we here introduce an environmental DNA-based approach for tracing two common kelp species in Nordic marine sediments, establishing a basis for estimating the organic carbon buried from the targeted species. We developed and tested species-specific quantitative PCR (qPCR) assays for Saccharina latissima and Laminaria hyperborea . Next, we applied the assays on 79 marine surface (0–2 cm) sediment samples along the Norwegian coast (58° N to 72° N), ranging from shallow nearshore (8.1 m) to deep offshore locations (1334 m). Kelp DNA was detected in 87% of the locations, with DNA from S. latissima and L. hyperborea detected in 73% and 72% of the locations, respectively. DNA from both species were detected together in 58% of the locations. Spatial analysis revealed higher kelp DNA concentrations in shallow, coastal areas, particularly for S. latissima while kelp DNA was largely absent at the offshore locations. Both species exhibited a strong correlation with the sediment total organic carbon (TOC) concentration. Interestingly, kelp eDNA concentrations and TOC concentrations were lower in areas where kelp forests were impacted by sea urchin grazing compared to non-impacted areas. Our study presents a novel method for tracing key kelp species and provides a framework to estimate their potential contributions to sediment carbon pools and assessing kelp carbon sequestration. This framework has the potential to improve assessment of blue carbon contributions in sediments and should also be applicable to other organisms beyond kelp.

• Bjorbækmo, Marit Frederikke Markussen; Brodie, Juliet; Krabberød, Anders Kristian; Logares, Ramiro; Fuss, Janina & Fredriksen, Stein [Show all 9 contributors for this article] (2023). 18S rDNA gene metabarcoding of microeukaryotes and epi-endophytes in the holobiome of seven species of large brown algae. Journal of Phycology. ISSN 0022-3646. 59(5), p. 859–878. doi: 10.1111/jpy.13377. Full text in Research Archive Show summary

  Brown algae (Phaeophyceae) are habitat-forming species in coastal ecosystems and include kelp forests and seaweed beds that support a wide diversity of marine life. Host-associated microbial communities are an integral part of phaeophyte biology, and whereas the bacterial microbial partners have received considerable attention, the microbial eukaryotes associated with brown algae have hardly been studied. Here, we used broadly targeted “pan-eukaryotic” primers (metabarcoding) to investigate brown algal-associated eukaryotes (the eukaryome). Using this approach, we aimed to investigate the eukaryome of seven large brown algae that are important and common species in coastal ecosystems. We also aimed to assess whether these macroalgae harbor novel eukaryotic diversity and to ascribe putative functional roles to the host-associated eukaryome based on taxonomic affiliation and phylogenetic placement. We detected a significant diversity of microeukaryotic and algal lineages associated with the brown algal species investigated. The operational taxonomic units (OTUs) were taxonomically assigned to 10 of the eukaryotic major supergroups, including taxonomic groups known to be associated with seaweeds as epibionts, endobionts, parasites, and commensals. Additionally, we revealed previously unrecorded sequence types, including novel phaeophyte OTUs, particularly in the Fucus spp. samples, that may represent fucoid genomic variants, sequencing artifacts, or undescribed epi-/endophytes. Our results provide baseline data and technical insights that will be useful for more comprehensive seaweed eukaryome studies investigating the evidently lineage-rich and functionally diverse symbionts of brown algae.

• Krabberød, Anders Kristian; Deutschmann, Ina Maria; Bjorbækmo, Marit Frederikke Markussen; Balagué, Vanessa; Giner, Caterina R. & Ferrera, Isabel [Show all 10 contributors for this article] (2022). Long-term patterns of an interconnected core marine microbiota. Environmental Microbiome. 17(1). doi: 10.1186/s40793-022-00417-1. Full text in Research Archive Show summary

  Background Ocean microbes constitute ~ 70% of the marine biomass, are responsible for ~ 50% of the Earth’s primary production and are crucial for global biogeochemical cycles. Marine microbiotas include core taxa that are usually key for ecosystem function. Despite their importance, core marine microbes are relatively unknown, which reflects the lack of consensus on how to identify them. So far, most core microbiotas have been defined based on species occurrence and abundance. Yet, species interactions are also important to identify core microbes, as communities include interacting species. Here, we investigate interconnected bacteria and small protists of the core pelagic microbiota populating a long-term marine-coastal observatory in the Mediterranean Sea over a decade. Results Core microbes were defined as those present in > 30% of the monthly samples over 10 years, with the strongest associations. The core microbiota included 259 Operational Taxonomic Units (OTUs) including 182 bacteria, 77 protists, and 1411 strong and mostly positive (~ 95%) associations. Core bacteria tended to be associated with other bacteria, while core protists tended to be associated with bacteria. The richness and abundance of core OTUs varied annually, decreasing in stratified warmers waters and increasing in colder mixed waters. Most core OTUs had a preference for one season, mostly winter, which featured subnetworks with the highest connectivity. Groups of highly associated taxa tended to include protists and bacteria with predominance in the same season, particularly winter. A group of 13 highly-connected hub-OTUs, with potentially important ecological roles dominated in winter and spring. Similarly, 18 connector OTUs with a low degree but high centrality were mostly associated with summer or autumn and may represent transitions between seasonal communities. Conclusions We found a relatively small and dynamic interconnected core microbiota in a model temperate marine-coastal site, with potential interactions being more deterministic in winter than in other seasons. These core microbes would be essential for the functioning of this ecosystem over the year. Other non-core taxa may also carry out important functions but would be redundant and non-essential. Our work contributes to the understanding of the dynamics and potential interactions of core microbes possibly sustaining ocean ecosystem function.

• Bjorbækmo, Marit Frederikke Markussen; Evenstad, Andreas; Røsæg, Line Lieblein; Krabberød, Anders Kristian & Logares, Ramiro (2019). The planktonic protist interactome: where do we stand after a century of research? The ISME Journal. ISSN 1751-7362. 14, p. 544–559. doi: 10.1038/s41396-019-0542-5. Full text in Research Archive Show summary

  Microbial interactions are crucial for Earth ecosystem function, but our knowledge about them is limited and has so far mainly existed as scattered records. Here, we have surveyed the literature involving planktonic protist interactions and gathered the information in a manually curated Protist Interaction DAtabase (PIDA). In total, we have registered ~2500 ecological interactions from ~500 publications, spanning the last 150 years. All major protistan lineages were involved in interactions as hosts, symbionts (mutualists and commensalists), parasites, predators, and/or prey. Predation was the most common interaction (39% of all records), followed by symbiosis (29%), parasitism (18%), and ‘unresolved interactions’ (14%, where it is uncertain whether the interaction is beneficial or antagonistic). Using bipartite networks, we found that protist predators seem to be ‘multivorous’ while parasite–host and symbiont–host interactions appear to have moderate degrees of specialization. The SAR supergroup (i.e., Stramenopiles, Alveolata, and Rhizaria) heavily dominated PIDA, and comparisons against a global-ocean molecular survey (TARA Oceans) indicated that several SAR lineages, which are abundant and diverse in the marine realm, were underrepresented among the recorded interactions. Despite historical biases, our work not only unveils large-scale eco-evolutionary trends in the protist interactome, but it also constitutes an expandable resource to investigate protist interactions and to test hypotheses deriving from omics tools.

• Freeman, Mark A.; Fuss, Janina; Kristmundsson, Árni; Bjorbækmo, Marit Fredrikke Markussen; Mangot, Jean-Francois & Campo, Javier del [Show all 9 contributors for this article] (2017). X-Cells Are Globally Distributed, Genetically Divergent Fish Parasites Related to Perkinsids and Dinoflagellates. Current Biology. ISSN 0960-9822. 27(11), p. 1645–1651. doi: 10.1016/j.cub.2017.04.045. Full text in Research Archive
• Jacobsen, Rannveig M; Kauserud, Håvard; Sverdrup-Thygeson, Anne; Bjorbækmo, Marit Markussen & Birkemoe, Tone (2017). Wood-inhabiting insects can function as targeted vectors for decomposer fungi. Fungal ecology. ISSN 1754-5048. 29, p. 76–84. doi: 10.1016/j.funeco.2017.06.006. Full text in Research Archive
• Krabberød, Anders Kristian; Bjorbækmo, Marit Markussen; Shalchian-Tabrizi, Kamran & Logares, Ramiro (2017). Exploring the oceanic microeukaryotic interactome with metaomics approaches. Aquatic Microbial Ecology. ISSN 0948-3055. 79(1), p. 1–12. doi: 10.3354/ame01811. Full text in Research Archive
• Bjorbækmo, Marit Markussen; Carlsen, Tor; Brysting, Anne Krag; Vrålstad, Trude; Høiland, Klaus & Ugland, Karl Inne [Show all 9 contributors for this article] (2010). High diversity of root associated fungi in both alpine and arctic Dryas octopetala. BMC Plant Biology. 10. doi: 10.1186/1471-2229-10-244. Full text in Research Archive Show summary

  Background Dryas octopetala is a widespread dwarf shrub in alpine and arctic regions that forms ectomycorrhizal (ECM) symbiotic relationships with fungi. In this study we investigated the fungal communities associated with roots of D. octopetala in alpine sites in Norway and in the High Arctic on Svalbard, where we aimed to reveal whether the fungal diversity and species composition varied across the Alpine and Arctic regions. The internal transcribed spacer (ITS) region of nuclear ribosomal DNA was used to identify the fungal communities from bulk root samples obtained from 24 plants. Results A total of 137 operational taxonomic units (OTUs) were detected (using 97% similarity cut off during sequence clustering) and well-known ECM genera such as Cenococcum, Cortinarius, Hebeloma, Inocybe and Tomentella occurred frequently. There was no decrease in fungal diversity with increasing latitude. The overall spatial heterogeneity was high, but a weak geographical structuring of the composition of OTUs in the root systems was observed. Calculated species accumulation curves did not level off. Conclusions This study indicates that the diversity of fungi associated with D. octopetala does not decrease in high latitude arctic regions, which contrasts observations made in a wide spectrum of other organism groups. A high degree of patchiness was observed across root systems, but the fungal communities were nevertheless weakly spatially structured. Non-asymptotical species accumulation curves and the occurrence of a high number of singletons indicated that only a small fraction of the fungal diversity was detected.

View all works in NVA

• Malicki, Brunon; Kauserud, Håvard; Morgado, Luis; Nordén, Björn; Nordén, Jenni & Bjorbækmo, Marit Frederikke Markussen (2021). Unearthing the factors driving eukaryotic diversity in boreal forest soils. Full text in Research Archive
• Haraldsen, Arthur Alexander Blørstad; Bjorbækmo, Marit Markussen; Mangot, Jean-Francois; Fuss, Janina; Shalchian-Tabrizi, Kamran & Hansen, Haakon [Show all 7 contributors for this article] (2015). Protist diversity in a marine and lacustrine system: Patterns across a salinity gradient. Full text in Research Archive Show summary

  During the last decade, the improvement of high-throughput sequencing (HTS) techniques has substantially increased our insight into microbial ecology, by capturing a much more detailed picture of their diversity. Due to the increasing amount of data obtained by HTS methods, specific questions on the biogeography and factors explaining the distribution of these microorganisms can now be fully examined. Here, the composition and structure of a metabolically active benthic protistan community was investigated along a salinity gradient of closely associated marine and freshwater systems. Amplicons of rDNA and rRNA, were sequenced using the Illumina MiSeq technology. This approach seemed to successfully capture the majority of the protist community in these habitats. The marine environments displayed a higher species richness compared to the lacustrine systems investigated, and a considerable difference in protist composition was observed between marine and freshwater systems. Nevertheless, some protists were found in both saline and freshwater environments, indicating the ability to survive rather diverse environmental conditions. It is noteworthy that some of the OTUs from both habitats form putative new clades in the enigmatic X-cell group.

• Fuss, Janina; Mangot, Jean-Francois; Bjorbækmo, Marit Markussen; Freeman, Mark A.; Bass, David & Shalchian-Tabrizi, Kamran [Show all 7 contributors for this article] (2015). THE ENIGMATIC BASAL ALVEOLATE PARASITE X-CELL: CAN MULTIPLE GENOMIC APPROACHES REVEAL MORE? Full text in Research Archive
• Bjorbækmo, Marit Markussen; Neumann, Ralf Stefan; Haraldsen, Arthur Alexander Blørstad & Shalchian-Tabrizi, Kamran (2015). HIDDEN PROTIST PARASITES: HOW CAN THEY BE DETECTED? Full text in Research Archive
• Fuss, Janina; Grønneberg, Estelle; Gylt, Torbjørn; Bjorbækmo, Marit Markussen; Mangot, Jean-Francois & Shalchian-Tabrizi, Kamran [Show all 7 contributors for this article] (2015). Pee, poo and parasitic protists - what is living inside the fish we eat? Full text in Research Archive
• Bjorbækmo, Marit Markussen; Neumann, Ralf Stefan; Haraldsen, Arthur Alexander Blørstad & Shalchian-Tabrizi, Kamran (2015). Expanding our knowledge about parasites using PATHOS-DB (The PArasiTe–HOSt-DataBase). Full text in Research Archive
• Bjorbækmo, Marit Markussen; Brysting, Anne Krag; Carlsen, Tor; Høiland, Klaus; Geml, Jozsef & Schumacher, Trond [Show all 8 contributors for this article] (2008). The ectomycorrhizal fungal community associated with alpine and arctic populations of Dryas octopetala along a latitudinal gradient. Full text in Research Archive
• Hakvåg, Sigrid; Andrews, Adam Jon; Bjorbækmo, Marit Frederikke Markussen & Piarulli, Stefani (2025). Spread of harmful microorganisms through fouling of ships - A brief literature review. SINTEF Ocean AS. ISSN 9788214072563. Full text in Research Archive Show summary

  The IMO 2023 Biofouling Management Guidelines and 2025 guidance aim to prevent fouling on ships and minimize the spread of non-native species (MEPC 378(80)), by recommending in-water cleaning (IWC) with effluent treatment, ensuring that only particles, including organisms, smaller than 10 μm in all dimensions should be released. The objectives of this brief literature study have been (i) to identify pathogenic microorganisms smaller than 10 μm that may occur as symbionts of macroorganisms fouling the hulls of marine vessels, and that could potentially be released under current guidance; and (ii) to identify the most relevant scientific knowledge gaps concerning pathogenic microorganisms associated with vessel biofouling. This report shortly describes the methods used and provides examples of identified microorganisms (smaller than 10 μm) reported to be pathogenic. Knowledge gaps related to microorganisms associated with fouling of marine vessels is also shortly addressed.

• Andrews, Adam Jon; Pardo, Juan; Bjorbækmo, Marit Frederikke Markussen & Berg, Paul Ragnar (2025). The potential of offshore wind farms to spread marine alien species. Norsk institutt for vannforskning (NIVA). ISSN 9788257778491. Full text in Research Archive Show summary

  Alien species are organisms introduced to new areas through human activities that have been associated with artificial structures in coastal zones. Offshore wind farms (OWFs), rapidly expanding across marine environments, provide novel artificial surfaces that may facilitate the establishment and spread of alien species in regions lacking natural habitats. In the southern North Sea, offshore energy structures already support such species, with similar patterns observed globally. Despite international and national policies calling for better understanding of alien marine species, their pathways, and early detection systems, Norway lacks an understanding of how OWFs will impact the spread of alien marine species. The impact of OWFs on alien species spread remains understudied globally. This study synthesizes current knowledge and explores three mechanisms by which OWFs may promote alien species dispersal to Norway: (1) acting as stepping-stones for regional and international spread, (2) enabling hitchhiking on vessels and structures between offshore and inshore areas, and (3) creating refuges for alien species due to fishing restrictions within OWFs. We highlight relevant alien taxa for each and identify knowledge gaps, aiming to support biodiversity protection efforts and meet national and commercial obligations.

• Evenset, Anita; Refseth, Gro Harlaug; Dale, Trine; Arnberg, Maj; Harendza, Astrid & Mikkelsen, Eirik Inge [Show all 18 contributors for this article] (2023). Miljøkonsekvenser av akvakultur og sameksisterende næringer. Akvaplan-niva. Full text in Research Archive
• Rinde, Eli; Moy, Siri Røang; Borgersen, Gunhild; Brkljacic, Marijana Stenrud; Fagerli, Camilla With & Gitmark, Janne Kim [Show all 15 contributors for this article] (2022). Utvikling av kartleggingsmetodikk og kriterier for lokalitetskvalitet for marine naturtyper. Norsk institutt for vannforskning (NIVA). ISSN 9788257775414. Full text in Research Archive Show summary

  Dette arbeidet er en videreføring av påbegynt arbeid fra 2020 og 2021 knyttet til kunnskap og metodeutvikling for kartlegging av marine naturtyper og for å kunne beskrive naturtypelokaliteters økologiske kvalitet. Arbeidet i 2022 har hatt søkelys på grunn bløtbunn, ålegrasenger og andre undervannsenger, tangsamfunn, sukkertareskog, stortareskog, ruglbunner, helofyttsaltvannssump,sterke tidevannsstrømmer og korallrev/sjøfjærsamfunn. I Oslofjorden har tidligere kartlagte forekomster av enkelte naturtyper, blitt re-kartlagt.

View all works in NVA