Articles

2025

van der Loos, L. M., Van De Weghe, L., Knoop, J., Daniels, B., D’hondt, S., Karremans, M., Perk, F., Steinhagen, S., Leliaert, F. & De Clerck, O. (2025). Incorporating historic specimens to reassess Ulva diversity in the Netherlands and Belgium. TAXON. https://onlinelibrary.wiley.com/doi/10.1002/tax.70058

Vargas-Murga, L., Dürrani, Ö., Adams, J., Steinhagen, S., Turan, G., Aruçi, E., … & Shpigel, M. (2025). Metal (oid) s in Ulva–should we be worried?. Food Chemistry, 145941. https://doi.org/10.1016/j.foodchem.2025.145941

Cardoso, I., Bartsch, I., Valentin K-U., Steinhagen, S., Buck, B. H., Hofmann, L. C. Naturally occurring protoplasts in two Ulva spp. reveal a previously underestimated proliferation process. Botanica Marina. 10.1515/bot-2025-0017

Schmidt, A. E., Steinhagen, S., Nilsson, K. P. R., Edlund, U., & Richter-Dahlfors, A. (2025). Spatial in situ mapping of cellulose and other biopolymers reveals the 3D tissue architecture in the green algae Ulva fenestrata. International Journal of Biological Macromolecules. https://doi.org/10.1016/j.ijbiomac.2025.145632

Steinhagen, S., Schrofner‐Brunner, E., Schrofner‐Brunner, B., Larsson, K., & Undeland, I. (2025). Green gold rush in the Baltic Sea: Investigating sea lettuce’s performance by distribution mapping of valuable compounds in a fluctuating environment. Journal of Phycology. https://doi.org/10.1111/jpy.70021

Andersson, M., Stedt, K., Steinhagen, S., Roques, J. A., Warwas, N., Doyle, D., Hinchcliffe, J., Hedén, I., Sundh, H., Pavia, H. & Sundell, K. (2025). Co-farming rainbow trout (Oncorhynchus mykiss) and sea lettuce (Ulva fenestrata) increased macroalgae protein content and positively affected fish welfare. Aquaculture, 742685. https://doi.org/10.1016/j.aquaculture.2025.742685

Toth, G., Hargrave, M., Stedt, K., Steinhagen, S., Visch, W. & Pavia, H. (2025). Advances in Swedish Seaweed Aquaculture: Enhancing Biomass Production and Quality. Reviews in Aquaculture, 17: e70031. https://doi.org/10.1111/raq.70031

Hofmann, L. C., Brakel, J., Bartsch, I., Montecinos Arismendi, G., Bermejo, R., Parente, M. I., … Steinhagen, S., … Wichard, T. (2025). A European biobanking strategy for safeguarding macroalgal genetic material to ensure food security, biosecurity and conservation of biodiversity. European Journal of Phycology, 1–24. https://doi.org/10.1080/09670262.2025.2480569

Trigo, J. P., Chamlagain, B., Thorén, J., Strand, R., Juanola, M. V. L., Steinhagen, S., … & Undeland, I. (2025). Sea lettuce (Ulva fenestrata) as a rich source of cobalamin (vitamin B12); both as processed whole biomass and as an extracted protein ingredient. Food Chemistry, 144302. https://doi.org/10.1016/j.foodchem.2025.144302

van der Loos, L. M., Steinhagen, S., Stock, W., Weinberger, F., D’hondt, S., Willems, A., & De Clerck, O. (2025). Low functional change despite high taxonomic turnover characterizes the Ulva microbiome across a 2000-km salinity gradient. Science Advances, 11(3), eadr6070. https://doi.org/10.1126/sciadv.adr6070

Steinhagen, S., Johansson, I., Specht, J., Enge, S., Larsson, K., Undeland, I., & Toth, G. B. (2025). Unlocking economic potential of the Ulva crop for low salinity environments: exploring the effect of salinity gradients on the performance and valuable compounds of Baltic Sea strains. Botanica Marina, (0). https://doi.org/10.1515/bot-2024-0079

Blomme, J., Wichard, T., & Steinhagen, S. (2024). Phylogeny and ecology of the green seaweed Ulva. Part II. Botanica Marina, (0). https://doi.org/10.1515/bot-2024-0104

2024

Trigo, J. P., Steinhagen, S., Stedt, K., Krona, A., Verhagen, S., Pavia, H., Abdollahi, M., & Undeland, I. (2024). A new method for protein extraction from sea lettuce (Ulva fenestrata) via surfactants and alkaline aqueous solutions. Food Chemistry, 141839. https://doi.org/10.1016/j.foodchem.2024.141839

Juanola, M. V. L., Steinhagen, S., Pavia, H., & Undeland, I. (2024). Brining as an effective method to stabilise sea lettuce (Ulva fenestrata) – impact on colour, texture, chemical characteristics and microbial dynamics. Algal Research, 103700. https://doi.org/10.1016/j.algal.2024.103700

Hofmann, L. C., Strauss, S., Shpigel, M., Guttman, L., Stengel, D. B., Rebours, C., … Steinhagen, S., … Meléndez-Martínez, A. J. (2024). The green seaweed Ulva: tomorrow’s “wheat of the sea” in foods, feeds, nutrition, and biomaterials. Critical Reviews in Food Science and Nutrition, 1–36. https://doi.org/10.1080/10408398.2024.2370489

Wendin, K., Stedt, K., Steinhagen, S., Pavia, H., Undeland, I. (2024). Sensory and consumer aspects of sea lettuce (Ulva fenestrata) – impact of harvest time, cultivation conditions and protein level. Future Foods, 100431, https://www.sciencedirect.com/science/article/pii/S2666833524000765

van der Loos, L.M., Steinhagen, S., Stock, W., Weinberger, F., D’hondt, S., Willems, A. & De Clerck, O. (2024). Functional stability despite high taxonomic turnover characterizes the Ulva microbiome across a 2,000 km salinity gradient. bioRxiv 2024.06.20.599874; doi: https://doi.org/10.1101/2024.06.20.599874

Trigo, J. P., Wendin, K., Steinhagen, S., Larsson, K., & Undeland, I. (2024). Sensory quality of emulsions prepared with the seaweed Ulva spp. or a derived protein ingredient. Future Foods, 100370. https://doi.org/10.1016/j.fufo.2024.100370

Steinhagen, S., Stedt, K., Trigo, J. P., Undeland, I., & Pavia, H. (2024). A step towards closing the food-waste gap in novel protein sources: Post-harvest protein boost of the seaweed crop Ulva by herring production tub water. Future Foods, 100347. https://doi.org/10.1016/j.fufo.2024.100347

van der Loos, L. M., De Wilde, C., Willems, A., De Clerck, O., & Steinhagen, S. (2024). The cultivated sea lettuce (Ulva) microbiome: Successional and seasonal dynamics. Aquaculture, 740692. https://doi.org/10.1016/j.aquaculture.2024.740692

Steinhagen, S., Wichard, T., & Blomme, J. (2024). Phylogeny and ecology of the green seaweed Ulva. Botanica Marina. https://doi.org/10.1515/bot-2024-0005

2023

Cardoso, I., Meiβner, A., Sawicki, A., Bartsch, I., Valentin, K.U., Steinhagen, S., Buck, B. & Hoffmann, L. (2023). Salinity as a tool for strain selection in recirculating land-based production of Ulva spp. from germlings to adults. J Appl Phycol. https://doi.org/10.1007/s10811-023-02960-x

Steinhagen, S., Hoffmann, S., Pavia, H. & Toth, G. (2023). Molecular identification of the ubiquitous green algae Ulva reveals high biodiversity, crypticity, and invasive species in the Atlantic-Baltic Sea region. Algal Research. https://doi.org/10.1016/j.algal.2023.103132

2022

Steinhagen, S., Kramár, L. & Toth, G.B. (2022). The unheeded existence of the tubular greens: molecular analyses reveal the distribution of a new Ulva species (Ulvophyceae, Chlorophyta), Ulva capillata sp. nov. in the Atlantic-Baltic Sea transect. J Appl Phycol. https://doi.org/10.1007/s10811-022-02886-w

Stedt, K., Toth, G., Davegård, J., Pavia, H., & Steinhagen, S (2022). Determination of nitrogen content in Ulva fenestrata by color image analysis–a rapid and cost-efficient method to estimate nitrogen content in seaweeds. Frontiers in Marine Science, 2510. https://doi.org/10.3389/fmars.2022.1081870

Stedt, K., Steinhagen, S., Trigo, J. P.,Kollander, B., Undeland, I., Toth, G. B., Wendin, K. & Pavia, H. (2022). Post-harvest cultivation with seafood process waters improves protein levels of Ulva fenestrata while retaining important food sensory attributes. Front. Mar. Sci. doi: https://10.3389/fmars.2022.991359

Tran, LA.T., Vieira, C., Steinhagen, S., Maggs, C. A., Hiraoka, M., Shimada, S., Nguyen, T. V., De Clercj, O. & Leliaert, F. (2022). An appraisal of Ulva (Ulvophyceae, Chlorophyta) taxonomy. Journal of Applied Phycology. https://doi.org/10.1007/s10811-022-02815-x

Steinhagen, S., Larsson, K., Olsson, J., Albers, E., Undeland, I., Pavia, H. & Toth, G. B. (2022). Closed life-cycle aquaculture of sea lettuce (Ulva fenestrata): performance and biochemical profile differ in early developmental stages. Front. Mar. Sci. 9:942679. doi: https://doi.org/10.3389/fmars.2022.942679

Juul, L., Steinhagen, S., Bruhn, A., Jensen, S.K., Undeland, I. & Dalsgaard, T.K. (2022). Combining pressing and alkaline extraction to increase protein yield from Ulva fenestrata biomass. Food and Bioproducts Processing. https://doi.org/10.1016/j.fbp.2022.05.006

van der Loos, L. M., D’hondt, S., Engelen, A. H., Pavia, H., Toth, G. B., Willems, A., Weinberger, F., De Clerck, O., & Steinhagen, S. (2022). Salinity and host drive Ulva-associated bacterial communities across the Atlantic–Baltic Sea gradient. Molecular Ecology, 00, 1– 18. https://doi.org/10.1111/mec.16462

Steinhagen, S., Enge, S., Cervin, G., Larsson, Edlund, U., Schmidt, A.E., Wahlström, N., Kollander, B., Pavia, H., Undeland, I. & Toth, G. (2022). Harvest time can affect the optimal yield and quality of sea lettuce (Ulva fenestrata) in a sustainable sea-based cultivation. Frontiers in Marine Science. doi: https://doi.org/10.3389/fmars.2022.816890

Stedt, K., Trigo, J.P., Steinhagen, S., Nylund, G.M., Forghani, B., Pavia, H. & Undeland, I. (2022). Cultivation of seaweeds in food production process waters: Evaluation of growth and crude protein content. Algal Research. 63 doi: https://doi.org/10.1016/j.algal.2022.102647

Afanasyev, D.F., Steinhagen, S., Abdullin, S.R., & Weinberger, F. (2022). Vegetation of the supralittoral and upper sublittoral zones of the Western German Baltic Sea coast: a phytosociological study. Botanica Marina. 63 doi: https://doi.org/10.1515/bot-2021-0026

2021

Juul, L., Danielsen, M., Nebel, C., Steinhagen, S., Bruhn, A., Jensen, S.K., Undeland, I. & Dalsgaard T.K. (2021). Ulva fenestrata protein – Comparison of three extraction methods with respect to protein yield and protein quality. Algal Research. doi: https://doi.org/10.1016/j.algal.2021.102496

Steinhagen, S., Enge, S., Larsson, K., Nylund, G.M., Albers, E., Pavia, H., Undeland, I. & Toth, G. (2021). Sustainable Large-Scale Aquaculture of the Northern Hemisphere Sea Lettuce, Ulva fenestrata, in an Off-Shore Seafarm. Journal of Marine Science and Engineering. 9(6), 615 doi: https://doi.org/10.3390/jmse9060615

Cai, C., Gu, K., Zhao, H., Steinhagen, S., He, P. & Wichard, T. (2021). Screening and verification of extranuclear genetic markers in green tide algae from the Yellow Sea. PLOS ONE 16(6): e0250968. doi: https://doi.org/10.1371/journal.pone.0250968

Trigo, J.P., Engström, N., Steinhagen, S., Juul, L., Harrysson, H., Toth, G.B., Pavia, H., Scheers, N., & Undeland, I. (2021). In vitro digestibility and Caco-2 cell bioavailability of sea lettuce (Ulva fenestrata) proteins extracted with pH-shift technology. FOOD CHEMISTRY. doi: 10.1016/j.foodchem.2021.129683

Steinhagen, S., Düsedau, L. & Weinberger, F. (2021). DNA barcoding of the German green supralittoral zone indicates the distribution and phenotypic plasticity of Blidingia species and reveals Blidingia cornuta sp. nov.. TAXON. doi: 10.1002/tax.12445

2020

Olsson, J., Raikova, S., Mayers, J.J., Steinhagen, S., Chuck, C.J., Nylund, G.M. & Albers, E. (2020). Effects of geographical location on potentially valuable components in Ulva intestinalis sampled along the Swedish coast. Applied Phycology. 1:1, 80-92, doi: 10.1080/26388081.2020.1827454

Wahlström, N., Steinhagen, S., Toth, G., Pavia, H., Edlund, U. (2020). Ulvan dialdehyde-gelatin hydrogels for removal of heavy metals and methylene blue from aqueous solution. Carbohydrate Polymers. doi: 10.1016/j.carbpol.2020.116841

Toth, G.B., Harrysson, H., Wahlström, N., Olsson, J., Oerbekke, A., Steinhagen, S., Kinnby, A., White, J., Albers, A., Edlund, U., Undeland, I. & Pavia, H. (2020). Effects of irradiance, temperature, nutrients, and pCO₂ on the growth and biochemical composition of cultivated Ulva fenestrata. Journal of Applied Phycology. doi: 10.1007/s10811-020-02155-8

Olsson, J., Toth, G.B., Oerbekke, A., Cvijetinovic, S., Wahlström, N., Harrysson, H., Steinhagen, S., Kinnby, A., White, J., Edlund, U., Undeland, I., Pavia, H. & Albers, E. (2020), Cultivation conditions affect the monosaccharide composition in Ulva fenestrata. Journal of Applied Phycology. doi: 10.1007/s10811-020-02138-9

2019

Steinhagen, S., Karez R. & Weinberger, F. (2019). Cryptic, alien, and lost species: Molecular diversity of Ulva sensu lato along the German coasts of the North and Baltic Seas. European Journal of Phycology. doi: 10.1080/09670262.2019.1597925.

Steinhagen, S., Barco, A., Wichard, T. & Weinberger, F. (2019), Conspecificity of the model organism Ulva mutabilis and Ulva compressa (Ulvophyceae, Chlorophyta). Journal of Phycology, 55: 25-36. doi: 10.1111/jpy.12804 

Steinhagen, S., Karez, R. & Weinberger, F. (2019) Molecular analysis of Ulva compressa (Chlorophyta, Ulvales) reveals its morphological plasticity, distribution and potential invasiveness on German North Sea and Baltic Sea coasts. European Journal of Phycology, 54:1, 102-114, doi: 10.1080/09670262.2018.1513167 

2018

Steinhagen, S., Karez, R. & Weinberger, F. (2018). Surveying seaweeds from the Ulvales and Fucales in the world’s most frequently used artificial waterway, the Kiel Canal. Botanica Marina, 62(1), pp. 51-61. doi: 10.1515/bot-2018-0020 

Weinberger, F., Steinhagen, S., Afanasyev, D. &Karez, R. (2018). New records from the southern North Sea and first records from the Baltic Sea of Kornmannia leptoderma. Botanica Marina, 62(1), pp. 63-73. doi: 10.1515/bot-2018-0019 

2016-2017

Afanasyev, D., Kamnev, A., Sushkova, E., Steinhagen, S. (2016). A field guide to Ulvaspecies found in the Black, Azov, Caspian Seas and Eastern Baltic/ Edited by Prof. I.P. Yermakov, Publishing house Pero, Moscow, Russia.

Steinhagen, S. & Weinberger, F. (2016). Ulva und verwandte Grünalgen an Schleswig-Holsteins Küsten – Eine Revision des Arteninventars. Veröffentlichungen des Landesamtes für Landwirtschaft, Umwelt und ländliche Räume Schleswig-Holstein. Vergabenummern: 0608.451410; 0608.451412. 

Dr. Sophie Steinhagen