Dr. Greta Reintjes


Department of Molecular Ecology

MPI for Marine Microbiology
Celsiusstr. 1
D-28359 Bremen




+49 421 2028-928

Dr. Greta Reintjes

Main Research Interests

Marine primary production accounts for half of the Earth’s carbon fixation and therefore has a significant impact on the global carbon cycle. However, although marine primary producers fix such a significant fraction of carbon, their biomass makes up only a small fraction of the total organic carbon pool. This is due to the extremely high turnover of phytoplankton and phytoplankton-derived organic matter within the oceans. This turnover is mediated by marine heterotrophic microorganisms (Bacteria and Archaea). Marine microorganisms therefore significantly affect the global
carbon cycle.
My research objectives are to investigate how the taxonomic and functional diversity of marine microorganisms affects the bacterially mediated carbon turnover in the Ocean.







I am currently working on:

  • Developing methods which enable shipboard high-throughput analyses of microbial diversity and abundance. These methods were developed to overcome the time delay between sampling and results and enable a comprehensive interpretation of the microbial community composition even in remote sampling sites.
  • Exploring the biogeographical distribution patterns of the free-living (FL) and particle-associated (PA) bacterial communities across different provinces of the Atlantic Ocean.
  • Investigating alternative substrate utilization mechanisms in marine bacteria and developing methods to quantitatively analyze substrate uptake in environmental samples. This is achieved by using a fluorescently labelled polysaccharide (FLA-PS), fluorescence in situ hybridization (FISH) and super-resolution structured illumination microscopy (SR-SIM).
  • Linking individual microbial groups to specific substrate utilisation mechanisms
  • Investigating the manner in which phylogenetic and functional difference in microbial communities affect the turnover of organic matter in the ocean.


Microbial loop
The microbial loop is a representation of the microbially mediated turnover of dissolved organic matter (DOM) and particulate organic matter (POM) in the marine environment. Carbon dioxide is fixed by phytoplankton in the surface oceans. The fixed organic matter is available as dissolved organic matter (DOM) to marine microorganisms and particulate organic matter (POM) to marine microorganisms and marine consumers such as zooplankton. Phytoplankton biomass enters the marine food web via the consumption by marine zooplankton. Additionally, the sloppy grazing of biomass by consumers, viral lysis and cell death of phytoplankton releases POM and DOM. DOM and POM are degraded and remineralised by marine microorganisms making essential nutrients available for primary production.
Visualisation of substrate uptake by single cells
Visualisation of fluorescent substrate uptake by single cells

Publications and Awards

Annette-Barthelt-Preis für Meeresforschung
Reintjes, G., Arnosti, C., Fuchs, B.M., and Amann, R. (2017) An alternative
polysaccharide uptake mechanism of marine bacteria. ISME J 11: 1640-1650.
Boedeker, C., Schüler, M., Reintjes, G., Jeske, O., van Teeseling, M.C.F., Jogler, M. et
al. (2017) Determining the bacterial cell biology of Planctomycetes. Nature
Communications 8: 14853.
Teeling H, Fuchs BM, Bennke CM, Krüger K, Chafee M, Kappelmann L, Reintjes G, Waldmann J, Quast C, Glöckner FO, Lucas J, Wichels A, Gerdts G, Wiltshire KH, Amann RI (2016) Recurring patterns in bacterioplankton dynamics during coastal spring algae blooms. eLife 5:e11888
Bennke, C.M., Reintjes, G., Schattenhofer, M., Ellrott, A., Wulf, J., Zeder, M., and Fuchs, B.M. (2016) Modification of a High- Throughput Automatic Microbial Cell Enumeration System for Ship Board Analyses. Applied and Environmental Microbiology 82: 3289-3296.

Presentations at Scientific Conferences

SAME15 (03.09.2017 - 09.09.2017), Zagreb, Croatia.
Poster presentation, title: “On-site microbial diversity and abundance analysis in the remotest part of the world’s oceans, the South Pacific Gyre”

ISME 2016 (21.08.2016 – 26.08.2016), Montreal Canada
Oral presentation, title: “The advantage of being selfish in marine surface waters”

GRS and GRC for Chemical Oceanography (21.08.2016 – 26.08.2016), Boston, USA
Oral and poster presentation, title: “Selfish bacteria, external degraders, and cheaters: a rogue’s gallery of microbial carbon processing inn the oceans.

25 Years AMT Conference (23.06.2015 – 25.06.2015), Plymouth, UK
Oral Presentation, title: “Microbial Community Composition of the Atlantic Ocean”

VAAM 2015 (30.03.2015 – 04.04.2015), Marburg, Germany
Oral presentation, title: “Polysaccharide hydrolysis and visualisation of uptake across contrasting oceanic provinces in the Atlantic Ocean”

ISME 2014 (24.08.2014 – 29.08.2014), Seoul, South Korea
Poster presentation, title: “Discrepancy of NGS and FISH based bacterial abundances along the Atlantic meridional transect 22”

VAAM 2013 (10.03.2013 – 13.03.2013), Bremen, Germany
Poster presentation, title: “Microbial and Picoeukaryotic Community Composition of the Atlantic Ocean”


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