Royal Netherlands Institute for Sea Research
Phone number
+31 (0)222 36 9521
Head of Analytical Laboratory
  • Microbial ecology in marine pelagic
  • Invertebrate host - microbe associations
  • Environmental DNA
  • Molecular diagnostics of marine organisms in general
  • Physiology of the calcifying phytoplankter Emiliania huxleyi

Dr. Judith van Bleijswijk Tierens Verhagen

Head of Analytical Laboratory

Tracking genetic traces in the sea and in faeces

Molecular ecologist Judith van Bleijswijk searches for genetic traces that all conceivable types of organisms leave behind in the environment, the so-called eDNA. ‘Fish, mammals, … all organisms leave DNA behind in the environment via the release of slime or skin cells, for example. In 2020, we were able to describe in the scientific literature that those traces form a useful reflection of the life present. Of course, those traces are strongly diluted in the sea. Nevertheless, in a single coffee mug filled with water from the Marsdiep, I can easily find the genetic traces of 15 different fish species. And that allows research on fish without catching a single one.’

Genetics versus the fishing net

‘The database of genetic information of organisms in the Wadden Sea is already quite complete. That means that we can recognise the majority of organisms using DNA methods. Obviously, that is far more difficult for areas such as the Atlantic Ocean. There are many species that we do not even know about, let alone that we could identify their DNA in a water sample.’

‘Searching for traces of DNA is far more sustainable and animal-friendly than capturing animals for research. Yet at the same time, we cannot use this technique for everything that could be achieved with a fishing vessel. For example, we obtain information about the relative mass abundance of species, but we cannot say anything about the number or the size classes of the fish found. On the other hand, we can probably better detect species that hide in complex environments such as coral reefs than our fellow researcher using a net.’

Bird faeces and marine fungi

‘The analysis of DNA traces can be applied to many more samples. For example, we are also helping our colleagues from the red knot research with the analysis of bird faeces, as we can identify the insects that these birds have eaten. That subsequently allows them to learn more about the effects of the changing climate on the breeding success of these birds. Furthermore, we are investigating the role of fungi in seas and oceans. This is still such a young area that we recently added more than 300 new marine fungal cultures to the collection of the Westerdijk Institute of Fungal Biodiversity.’

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Current projects

  • Environmental DNA    - of fishes on multiple locations in the Wadden Sea (with Suzanne Poiesz)                                                        - of fishes over a North Sea transect (with Rob Witbaard)                                                                                 - of deep sea fishes (with Furu Mienis)

  • Microbial ecology of Whithard Canyon (with Furu Mienis and Sofia Ledin)
  • Diagnostics of Methanotrophs in North Sea water samples (with Helge Niemann and Tim de Groot)
  • Diagnostics of Ammodytes species (with Rob Witbaard and Geert Aarts)
  • Marine fungi                 - their role in the degradation of algae (with Ronald de Vries, WFBI)                                                                  - transport via dessert dust (with Jan-Berend Stuut)                                                                                             - marine genotypes of Malassezia (with Hans de Cock, UU)
  • Food web analyses      

                                             - What do red knot chicks eat in the Arctic and is there a trophic    

                                              mismatch due   to warming? (with Jan van Gils and Misha Zhemchuzhnikov)


Linked news

Monday 26 October 2020
DNA-based method pushes marine benthic research to next level
Communities living in and near the seabed (benthos) are crucial components of the marine ecosystem. High benthic biodiversity contributes to healthy seas and oceans. Understanding changes in these communities starts with observation and monitoring.…
Monday 27 July 2020
Judith van Bleijswijk zondag op Radio Texel
Zondag 2 augustus de zevende NIOZ Natuurwijzer op Radio Texel: Radiomaker Mathijs Deen spreekt dit keer met moleculair bioloog dr. Judith van Bleijswijk die zoekt naar de genetische sporen die alle denkbare organismen achterlaten in het milieu, het…

Linked blogs

Wednesday 18 November 2020
NIOZ podcast Van Delta tot Diepzee aflevering 5 De zee als oermoeder, eDNA en schimmels
Microbiologe Judith van Bleijswijk wordt blij van schimmels en kan toveren met een emmertje zeewater. Daaraan kan ze zien wat er beneden, onder het oppervlak en dus aan het oog onttrokken, langs is gezwommen. Alleen maar door in dat emmertje te…

NIOZ publications

  • 2023
    van Duyl, F.C.; van Bleijswijk, J.D.L.; Wuchter, C.; Witte, H.J.; Coolen, M.J.L.; Bak, R.P.M.; Engelmann, J.C.; Nugues, M.M. (2023). Recovery patterns of the coral microbiome after relief of algal contact. J. Sea Res. 191: 102309.
  • 2022
    Klunder, L.; van Bleijswijk, J.D.L.; Kleine Schaars, L.; van der Veer, H.W.; Luttikhuizen, P.C.; Bijleveld, A. (2022). Quantification of marine benthic communities with metabarcoding. Mol. Ecol. Resour. 22(3): 1043-1054.
  • 2021
    Klunder, L.; van Bleijswijk, J.D.L.; Kleine Schaars, L.; van der Veer, H.W.; Luttikhuizen, P.C. (2021). Impact of mechanical Arenicola dredging on the benthic fauna communities: assessed by a morphological and molecular approach. Mar. Ecol. Prog. Ser. 673: 17-28.
    Peperzak, L.; van Bleijswijk, J. (2021). False-positive enterococci counts in seawater with the IDEXX Enterolert-E most probable number technique caused by Bacillus licheniformis. Environm. Sc. & Poll. Res. 28: 10654-10660.
  • 2020
    Abdala Asbun, A.; Besseling, M.A.; Balzano, S.; van Bleijswijk, J.D.L.; Witte, H.J.; Villanueva, L.; Engelmann, J.C. (2020). Cascabel: A scalable and versatile amplicon sequence data analysis pipeline delivering reproducible and documented results. Frontiers in Genetics 11: 489357.
    Haalboom, S.; Price, D.M.; Mienis, F.; van Bleijswijk, J.D.L.; de Stigter, H.; Witte, H.J.; Reichart, G.-J.; Duineveld, G.C.A. (2020). Patterns of (trace) metals and microorganisms in the Rainbow hydrothermal vent plume at the Mid-Atlantic Ridge. Biogeosciences 17(9): 2499-2519.
    Klunder, L.; De Stigter, H.; Lavaleye, M.S.S.; van Bleijswijk, J.D.L.; van der Veer, H.W.; Reichart, G.-J.; Duineveld, G.C.A. (2020). A molecular approach to explore the background benthic fauna around a hydrothermal vent and their larvae: Implications for future mining of deep-sea SMS deposits. Front. Mar. Sci. 7: 134.
    Klunder, L.; Lavaleye, M.; Filippidi, A.; van Bleijswijk, J.; Reichart, G.-J.; van der Veer, H.W.; Duineveld, G.C.A.; Mienis, F. (2020). Impact of an artificial structure on the benthic community composition in the southern North Sea: assessed by a morphological and molecular approach. ICES J. Mar. Sci./J. Cons. int. Explor. Mer 77(3): 1167-1177.
    van Bleijswijk, J.D.L.; Engelmann, J.C.; Klunder, L.; Witte, H.J.; Witte, J.IJ.; van der Veer, H.W. (2020). Analysis of a coastal North Sea fish community: Comparison of aquatic environmental DNA concentrations to fish catches. Environmental DNA 2(4): 429-445.
    van Walraven, L.; van Bleijswijk, J.; van der Veer, H.W. (2020). Here are the polyps: in situ observations of jellyfish polyps and podocysts on bivalve shells. PeerJ 8: e9260.
  • 2019
    Klunder, L.; Duineveld, G.C.A.; Lavaleye, M.S.S.; van der Veer, H.; Palsboll, P.J.; van Bleijswijk, J.D.L. (2019). Diversity of Wadden Sea macrofauna and meiofauna communities highest in DNA from extractions preceded by cell lysis. J. Sea Res. 152: 101764.
  • 2018
    Bale, N.J.; Hopmans, E.C.; Dorhout, D.; Stal, L.J.; Grego, M.; van Bleijswijk, J.D.L.; Sinninghe Damsté, J.S.; Schouten, S. (2018). A novel heterocyst glycolipid detected in a pelagic N2 -fixing cyanobacterium of the genus Calothrix. Org. Geochem. 123: 44-47.
    Balzano, S.; Lattaud, J.; Villanueva, L.; Rampen, S.W.; Brussaard, C.P.D.; van Bleijswijk, J.; Bale, N.; Sinninghe Damsté, J.S.; Schouten, S. (2018). A quest for the biological sources of long chain alkyl diols in the western tropical North Atlantic Ocean. Biogeosciences 15(19): 5951-5968.
    Klunder, L.; van Bleijswijk, J.; van der Veer, H. (2018). Effect of an energy turbine on fish eDNA as indicator for species composition. NIOZ-rapport, 2018(7). NIOZ: Texel. 21 pp.
    Luttikhuizen, P.C.; van den Heuvel, F.H.M.; Rebours, C.; Witte, H.J.; van Bleijswijk, J.D.L.; Timmermans, K. (2018). Strong population structure but no equilibrium yet: Genetic connectivity and phylogeography in the kelp Saccharina latissima (Laminariales, Phaeophyta). Ecol. Evol. 8(8): 4265-4277.
  • 2017
    Maat, D.S.; Biggs, T.; Evans, C.; van Bleijswijk, J.D.L.; van der Wel, N.; Dutilh, B.E.; Brussaard, C.P.D. (2017). Characterization and Temperature Dependence of Arctic Micromonas polaris Viruses. Viruses 9(6): 134.
  • 2016
    de Bakker, D.M.; Meesters, E.H.W.G.; van Bleijswijk, J.D.L.; Luttikhuizen, P.C.; Breeuwer, H.J.A.J.; Becking, L.E. (2016). Population Genetic Structure, Abundance, and Health Status of Two Dominant BenthicSpecies in the Saba Bank National Park, Caribbean Netherlands: Montastraea cavernosa and Xestospongia muta. PLoS One 11: e0155969.
    Maat, D.S.; van Bleijswijk, J.D.L.; Witte, H.J.; Brussaard, C.P.D. (2016). Virus production in phosphorus-limited Micromonas pusilla stimulated by a supply of naturally low concentrations of different phosphorus sources, far into the lytic cycle. FEMS Microbiol. Ecol. 92: fiw136.
    van Walraven, L.; Driessen, F.; van Bleijswijk, J.; Bol, A.; Luttikhuizen, P.C.; Coolen, J.; Bos, O.G.; Gittenberger, A.; Schrieken, N.; Langenberg, V.T.; van der Veer, H.W. (2016). Where are the polyps? Molecular identification, distribution and population differentiation of Aurelia aurita jellyfish polyps in the southern North Sea area. Mar. Biol. (Berl.) 163: 172.
  • 2015
    Leopold, M.F.; Begeman, L.; van Bleijswijk, J.D.L.; IJsseldijk, L.L.; Witte, H.; Gröne, A. (2015). Exposing the grey seal as a major predator of harbour porpoises. Proc. R. Soc. Lond. (Biol. Sci.) 282(1802): 20142429.
    Martínez Martínez, J.; Boere, A.; Gilg, I.; van Lent, J.W.M.; Witte, H.; van Bleijswijk, J.D.L.; Brussaard, C.D.P. (2015). New lipid envelope-containing dsDNA virus isolates infecting Micromonas pusilla reveal a separate phylogenetic group. Aquat. Microb. Ecol. 74: 17-28.
    van Bleijswijk, J.D.L.; Whalen, C.; Duineveld, G.C.A.; Lavaleye, M.S.S.; Witte, H.J.; Mienis, F (2015). Microbial assemblages on a cold-water coral mound at the SE Rockall Bank (NE Atlantic): interactions with hydrography and topography. Biogeosciences 12(14): 4493-4496.
  • 2014
    Philippart, C.J.M.; van Bleijswijk, J.; Kromkamp, J.C.; Zuur, A.F.; Herman, P.M.J. (2014). Reproductive phenology of coastal marine bivalves in a seasonal environment. J. Plankton Res. 36(6): 1512-1527.
    van Bleijswijk, J.; Begeman, L.; Witte, H.J.; IJsseldijk, L.L.; Brasseur, S.M.J.M.; Gröne, A.; Leopold, M.F. (2014). Detection of grey seal Halichoerus grypus DNA in attack wounds on stranded harbour porpoises Phocoena phocoena. Mar. Ecol. Prog. Ser. 513: 277-281.
    Wijgerde, T.; Silva, C.I.F.; Scherders, V.; van Bleijswijk, J.; Osinga, R. (2014). Coral calcification under daily oxygen saturation and pH dynamics reveals the important role of oxygen. Biology Open 3: 489-493.
  • 2013
    Bergauer, K.; Sintes, E.; van Bleijswijk, J.; Witte, H.; Herndl, G.J. (2013). Abundance and distribution of archaeal acetyl-CoA/propionyl-CoA carboxylase genes indicative for putatively chemoautotrophic Archaea in the tropical Atlantic's interior. FEMS Microbiol. Ecol. 84(3): 461-473.
    Bongaerts, P.; Frade, P.R.; Ogier, J.J.; Hay, K.B.; van Bleijswijk, J.; Englebert, N.; Vermeij, M.J.A.; Bak, R.P.M.; Visser, P.M.; Hoegh-Guldberg, O. (2013). Sharing the slope: depth partitioning of agariciid corals and associated Symbiodinium across shallow and mesophotic habitats (2-60 m) on a Caribbean reef. BMC Evol. Biol. 13: 1-14.
    Cardoso, J.F.M.F.; van Bleijswijk, J.D.L.; Witte, H.; van Duyl, F.C. (2013). Diversity and abundance of ammonia-oxidizing Archaea and Bacteria in tropical and cold-water coral reef sponges. Aquat. Microb. Ecol. 68(3): 215-230.
  • 2012
    Philippart, C.J.M.; Amaral, A.; Asmus, R.; van Bleijswijk, J.; Bremner, J.; Buchholz, F.; Cabanellas-Reboredo, M.; Catarino, D.; Cattrijsse, A.; Charles, F.; Comtet, T.; Cunha, A.; Deudero, S.; Duchêne, J.-C.; Fraschetti, S.; Gentil, F.; Gittenberger, A.; Guizien, K.; Gonçalves, J.M.; Guarnieri, G.; Hendriks, I.; Hussel, B.; Pinheiro Vieira, R.; Reijnen, B.T.; Sampaio, I.; Serrão, E.; Sousa Pinto, I.; Thiebaut, E.; Viard, F.; Zuur, A.F. (2012). Spatial synchronies in the seasonal occurrence of larvae of oysters (Crassostrea gigas) and mussels (Mytilus edulis/galloprovincialis) in European coastal waters. Est., Coast. and Shelf Sci. 108: 52-63.
    Schouten, S.; Pitcher, A.; Hopmans, E.C.; Villanueva, L.; van Bleijswijk, J.; Sinninghe Damsté, J.S. (2012). Intact polar and core glycerol dibiphytanyl glycerol tetraether lipids in the Arabian Sea oxygen minimum zone: I. Selective preservation and degradation in the water column and consequences for the TEX86. Geochim. Cosmochim. Acta 98: 228-243.
  • 2011
    Luttikhuizen, P.C.; Bol, A.; Witte, H.; van Bleijswijk, J.; Haddrath, O.; Baker, A.J.; Piersma, T.; Reneerkens, J.; Piersma, T. (2011). Novel and cross-species microsatellite markers for parentage analysis in Sanderling Calidris alba. J. Ornithol. 152(3): 807-810.

Linked projects

UUNIOZ_Harmful Algal Blooms
Laura Villanueva
Utrecht University
Project duration
1 Jan 2021 - 31 Dec 2025