Royal Netherlands Institute for Sea Research
Phone number
+31 (0)222 36 9446
Ocean Systems (OCS)
Universiteit Gent
Karline Soetaert
  • Pulse-chase experiments with stable isotopes (SI)
  • Compound-specific isotope analysis (fatty acids, amino acids)
  • Linear inverse modelling of benthic food-webs
  • Absorbance and fluorescence measurements of DOM (CDOM, FDOM)
  • Annotation of still images and processing of video material

Dr. Tanja Stratmann


(photo courtesy: ROV Kiel 6000, Geomar, Kiel, Germany)

Research interests

  •            Carbon cycling in polar waters and sea ice
  •       Structure and stability of deep-sea food webs
  •       Nutrient and oxygen fluxes of benthic megafauna (e.g. Porifera, Holothuroidea)
  •       Environmental impact of deep-sea mining
  •       Deep-sea diversity and ecology

Linked news

Friday 07 July 2023
Dossier: deep sea
Two-thirds of the earth's surface consists of oceans and seas. The deep-sea is the largest biome on earth, making up 90% of the ocean’s volume. Below 200 meters depth it is dark, as hardly any sunlight can penetrate, the pressure increases and food…
Thursday 22 June 2023
Deep seabed mining stakeholders meet to discuss how to protect hydrothermal vents
Stakeholder event: Current developments on deep seabed mining and the use of area-based management tools to protect hydrothermal vents
Monday 03 April 2023
"It is too early for commercial deep-sea mining"
"Extracting manganese nodules or other valuable metals from the bottom of the oceans is still fraught with many uncertainties. It is therefore far too early to proceed with commercial deep-sea mining at this time." So says marine biologist Sabine…
Monday 21 March 2022
Deep sea mining might start soon, still research needed
If it's up to mining companies, deep sea mining had already started many years ago. The International Seabed Authority (ISA) council 27th assembly starts today. Under pressure of several countries mining regulations are discussed. Independent…
Thursday 16 December 2021
2 Veni-grants for NIOZ researchers
The Netherlands Organisation for Scientific Research (NWO) has awarded a Veni grant worth 280,000 euros to 2 highly promising early career NIOZ scientists. The grant provides them with the opportunity to further elaborate their own ideas during a…
Thursday 10 June 2021
Sponges on valuable nodules enable high biodiversity ocean floor
Researchers from NIOZ and Germany have discovered that sponges, which like to settle on metallic nodules on the ocean floor, also provide a home for many other animals. Without the sponges, species richness in these deep-sea regions would be…
Tuesday 29 October 2019
Largest mapping of breathing ocean floor key to understanding global carbon cycle
Marine sediments play a crucial role in the global carbon cycle due to the oxygen consumption and CO2 respiration of the organisms that live in and on the ocean floor. To help predict the changing contribution of this respiration to the carbon cycle…
Thursday 27 September 2018
Diepzeemijnbouw veroorzaakt langdurige schade aan het ecosysteem
[English below Dutch] Het winnen van mangaanknollen in de diepzee levert langdurige milieuschade op. Dat concludeert NIOZ-onderzoekster Tanja Stratmann in haar proefschrift 'Benthic ecosystem response to polymetallic nodule extraction in the deep…
Tuesday 06 June 2017
Short-term effects of deep-sea mining waste on microbes and meiofauna at the seafloor
The addition of waste particles from deep-sea mining (iron ore mine tailings) affected the activity of nematodes and the microbial community in microcosm experiments with natural sediments collected at 200m depth in the Hardanger fjord (Norway).…

Linked blogs

Tuesday 13 December 2022
Deep sea mining would change the seafloor ecosystem for up to millions of years
“The unique and vulnerable ecosystems of the deep sea are the last ecosystems on earth that haven't been degraded by humans yet. In this muddy environment, potato-sized polymetallic nodules are the only hold-fast for immobile animals like corals,…

NIOZ publications

  • 2023
    Hoving, H.-J.; Boetius, A.; Dunlop, K.M.; Greinert, J.; Haeckel, M.; Jones, D.O.B.; Simon-Lledó, E.; Marcon, Y.; Stratmann, T.; Suck, I.; Sweetman, A.K.; Purser, A. (2023). Major fine-scale spatial heterogeneity in accumulation of gelatinous carbon fluxes on the deep seabed. Front. Mar. Sci. 10: 1192242.
    Stratmann, I.; Goersch, J.; Neuser, M.; Schindler, C.; Stratmann, T. (2023). Developing elastic–plastic material models for pressure measurement films in a steel–steel contact for smooth and rough surfaces. Journal of Tribology-Transactions of the Asme 145(7): 071501.
    Stratmann, T. (2023). Role of polymetallic-nodule dependent fauna on carbon cycling in the eastern Clarion-Clipperton Fracture Zone (Pacific). Front. Mar. Sci. 10: 1151442.
    Stratmann, T.; van Breugel, P.; Sweetman, A.K.; Van Oevelen, D. (2023). Deconvolving feeding niches and strategies of abyssal holothurians from their stable isotope, amino acid, and fatty acid composition. Mar. Biodiv. 53(6).
  • 2022
    Stratmann, T. (2022). The ProkaBioDen database, a global database of benthic prokaryotic biomasses and densities in the marine realm. Scientific Data 9: 179.
    Stratmann, T.; Simon-Lledó, E.; Morganti, T.M.; de Kluijver, A.; Vedenin, A.; Purser, A. (2022). Habitat types and megabenthos composition from three sponge-dominated high-Arctic seamounts. NPG Scientific Reports 12(1).
  • 2021
    Stratmann, T.; Soetaert, K.; Kersken, D.; van Oevelen, D. (2021). Polymetallic nodules are essential for food-web integrity of a prospective deep-seabed mining area in Pacific abyssal plains. NPG Scientific Reports 11(1): 12238.
  • 2020
    de Jonge, D.S.W.; Stratmann, T.; Lins, L.; Vanreusel, A.; Purser, A.; Marcon, Y.; Rodrigues, C.F.; Ravara, A.; Esquete, P.; Cunha, M.R.; Simon-Lledó, E.; van Breugel, P.; Sweetman, A.K.; Soetaert, K.; van Oevelen, D. (2020). Abyssal food-web model indicates faunal carbon flow recovery and impaired microbial loop 26 years after a sediment disturbance experiment. Prog. Oceanogr. 189: 102446.
    Kazanidis, G.; Orejas, C.; Borja, A.; Kenchington, E.; Henry, L.-A.; Callery, O.; Carreiro-Silva, M.; Egilsdottir, H.; Giacomello, E.; Grehan, A.; Menot, L.; Morato, T.; Ragnarsson, S.A.; Rueda, J.L.; Stirling, D.; Stratmann, T.; van Oevelen, D.; Palialexis, A.; Johnson, D.; Roberts, J.M. (2020). Assessing the environmental status of selected North Atlantic deep-sea ecosystems. Ecol. Indic. 119: 106624.
    Lund-Hansen, L.C.; Bendtsen, J.; Stratmann, T.; Tonboe, R.; Olsen, S.M.; Markager, S.; Sorrell, B.K. (2020). Will low primary production rates in the Amundsen Basin (Arctic Ocean) remain low in a future ice-free setting, and what governs this production? J. Mar. Syst. 205: 103287.
    Stratmann, T.; van Oevelen, D.; Martinez Arbizu, P.; Wei, C.L.; Liao, J.-X.; Cusson, M.; Scrosati, R.; Archambault, P.; Snelgrove, P.; Ramey-Balci, P.; Burd, B.J.; Kenchington, E.; Belley, R.; Soetaert, K. (2020). The BenBioDen database, a global database for meio-, macro- and megabenthic biomass and densities. Scientific Data 7: 206.
  • 2019
    Stratmann, T.; Soetaert, K.; Wei, C.L.; Lin, Y.-S.; Van Oevelen, D. (2019). The SCOC database, a large, open, and global database with sediment community oxygen consumption rates. Scientific Data 6: article number: 242.
    Sweetman, A.K.; Smith, C.R.; Shulse, C.N.; Maillot, B.; Lindh, M.; Church, M.J.; Meyer, K.S.; van Oevelen, D.; Stratmann, T.; Gooday, A.J. (2019). Key role of bacteria in the short-term cycling of carbon at the abyssal seafloor in a low particulate organic carbon flux region of the eastern Pacific Ocean. Limnol. Oceanogr. 64(2): 694-713.
  • 2018
    Brown, A.; Hauton, C.; Stratmann, T.; Sweetman, A.; Van Oevelen, D.; Jones, D.O.B. (2018). Metabolic rates are significantly lower in abyssal Holothuroidea than in shallow-water Holothuroidea. Royal Society Open Science 5: 172162.
    Stratmann, T. (2018). Benthic ecosystem response to polymetallic nodule extraction in the deep sea. PhD Thesis. Ghent University: Ghent. ISBN 9789082561159. XXV, 351 pp.
    Stratmann, T.; Lins, L.; Purser, A.; Rodrigues, C.F.; Ravara, A.; Cunha, M.R.; Simon-Lledó, E.; Jones, D.O.B.; Sweetman, A.K.; Köser, K.; Van Oevelen, D. (2018). Abyssal plain faunal carbon flows remain depressed 26 years after a simulated deep-sea mining disturbance. Biogeosciences 15(13): 4131-4145.
    Stratmann, T.; Mevenkamp, L.; Sweetman, A.K.; Vanreusel, A.; van Oevelen, D. (2018). Has phytodetritus processing by an abyssal soft-sediment community recovered 26 years after an experimental disturbance? Front. Mar. Sci. 5: 59.
    Stratmann, T.; Voorsmit, I.; Gebruk, A.; Brown, A.; Purser, A.; Marcon, Y.; Sweetman, A.K.; Jones, D.O.B.; Van Oevelen, D. (2018). Recovery of Holothuroidea population density, community composition, and respiration activity after a deep-sea disturbance experiment. Limnol. Oceanogr. 63(5): 2140-2153.
  • 2017
    Jones, D.O.B.; Kaiser, S.; Sweetman, A.K.; Smith, C.R.; Menot, L.; Vink, A.; Trueblood, D.; Greinert, J.; Billett, D.S.M.; Martinez Arbizu, P.; Radziejewska, T.; Singh, R.; Ingole, B.; Stratmann, T.; Simon-Lledó, E.; Durden, J.M.; Clack, M.R. (2017). Biological responses to disturbance from simulated deep-sea polymetallic nodulemining. PLoS One 12(2): e0171750.
    Mevenkamp, L.; Stratmann, T.; Guilini, K.; Moodley, L.; Van Oevelen, D.; Vanreusel, A.; Westerlund, S.; Sweetman, A.K. (2017). Impaired short-term functioning of a benthic community from a deep Norwegian Fjord following deposition of mine tailings and sediments. Front. Mar. Sci. 4(169): 1-16.
    Stratmann, T.; Lund-Hansen, L.C.; Sorrell, B.K.; Markager, S. (2017). Concentrations of organic and inorganic bound nutrients and chlorophyll a in the Eurasian Basin, Arctic Ocean, early autumn 2012. Regional Studies in Marine Science 9: 69-75.
  • 2015
    Lund-Hansen, L.C.; Markager, S.; Hancke, K.; Stratmann, T.; Rysgaard, S.; Ramløv, H.; Sorrell, B.K. (2015). Effects of sea-ice light attenuation and CDOM absorption in the water below the Eurasian sector of central Arctic Ocean (>88°N). Pol. Res. 34: 23978.

Linked projects

MIDAS_Managing Impacts of Deep-seA reSource exploitation
Dick van Oevelen
European Community
Project duration
1 Nov 2013 - 16 Feb 2018
Role of deep-sea sponges on carbon and nitrogen flows in deep-sea food webs
Tanja Stratmann
The Royal Netherlands Academy of Arts and Sciences
Project duration
1 Jan 2017 - 30 Jun 2017