Impressions and Methods

Ein Probensammelger?t steht an Deck des Forschungsschiffes Heincke

Research vessels enable us to access water samples from the oceans and the deep sea. Molecular and cological questions can be answered using environmental samples. Where does bacterial sugar degradation occur and under what conditions?

Automatisches Fluoreszenz-Mikroskop mit einer verstellbaren Bühne für Objekttr?ger und einem Computer mit einer ge?ffneten Software

Fluorescence microscopy with automatic image acquisition helps us to observe the degradation and uptake of sugar by bacteria. The microorganisms are counted and analysed on hundreds of images using software.

Science communication channel by Nahja Busse:

Instagram - @thesaltycell

Science Slam by Laura Pareigis:

YouTube-Video Science Slam

Molecular ecology is the study of how organisms interact with each other and with their environment. We use tools from genetics and molecular biology to understand relationships, diversity and evolution. We focus our research on the marine microbiome and the interactions between marine bacteria and their environment.

Live bacterial and algae cultures must not be contaminated with other microorganisms from the surroundings. This is why this work always takes place under the sterile cleanbench.

Marine bacteria have different requirements than terrestrial bacteria. Many marine microbes grow slowly or not at all under standard laboratory conditions. We cultivate pure cultures of marine bacteria with different media based on synthetic seawater compositions. By adjusting the carbon source concentration, we simulate natural, nutrient-poor marine environments. This allows us to study bacterial behaviour under different conditions.

Using a fluorescence microscope, the uptake of fluorescently labelled polysaccharides by bacteria can be visualised at the single cell level.

To analyse the DNA of a bacterial cell or a microbiome, we need to sequence the DNA. This means that we determine the exact order of the building blocks (A, T, C and G) in a DNA strand. We use a nanopore minion sequencer, which allows us to analyse the DNA structure with high accuracy. Sequencing allows us to gain insights into the genetic composition and functions of microorganisms.

[Translate to English:] Bacteria on Agar plate

The marine microbes we study are cultivated in our laboratory. This allows us to test their growth under different conditions (e.g. temperature, carbon source, pH) and find out how far-reaching their capabilities are and whether these correspond to their genetic potential.

The MiCarb Group utilises 3D printing to produce everyday laboratory equipment, including slide boxes, vortexers, tube storage boxes, racks in various sizes, clamps and clips, as well as some unique designs developed specifically for our applications. 3D printing reduces costs, minimises shipping and allows us to develop project-specific solutions directly in the lab.

H?nde mit blauen Handschuhen, die etwas pipettieren.

To find out which species we are dealing with, we use a molecular technique: 16S rRNA sequencing. Sounds complicated, but it is, so here it is in brief: 16S rRNA is like a fingerprint of a species. So if we analyse it and compare it with other "fingerprints", we can tell whether they have the same or a different print and thus identify the species.

In order to visualise marine microorganisms, they are collected on filters for subsequent microscopy.

Fluorescence-labelled bacteria can be sorted and examined independently. This allows bacteria to be separated from each other according to their properties and colouring.

? Greta Reintjes
Sample collector is lowered into the sea from a research vessel
? Laura Pareigis
Filtration systems in the laboratory of a research vessel. Here is the Thalassys filtration system from Dr. Greta Reintjes' start-up.
? Greta Reintjes
Diatoms (silica algae) in a water sample.
? Annemarie Popp, Universit?t Bremen
Liquid chromatography for the chemical synthesis of fluorescently labeled sugars.
? Greta Reintjes
Polysaccharides in jars.
? Greta Reintjes
A piece of European coastline.
? Greta Reintjes
Polysaccharides extracted from algae.
? Greta Reintjes
A washed-up macroalgae.
? Laura Pareigis
Sample collector on the Heincke in good weather.
? Laura Pareigis
Laura taking her samples on the Heincke in the summer of 2025.
Nahja presents her poster “Microbial Munchies” at the Ocean Floor Symposium 2025.
? Laura Pareigis
Laura is safe at work wearing a helmet on the ship. Here she is allowed to operate the CTD.
? Laura Pareigis
Laura takes samples from the North Sea on the Heincke in the summer of 2025.
? Laura Pareigis
Laura in front of the ship “Atlantic Explorer” in North Carolina (USA) in spring 2024.
? Laura Pareigis
Laura and the other research team members on the Atlantic Explorer in spring 2024.
? Laura Pareigis
Laura (left) and her team on the Heincke in the summer of 2025. Gregor W?hle (University of Bremen), Lucie Lemke (FU Berlin), and Mieke Kaiser (University of Kiel) were there.
? Greta Reintjes
Nahja loads a gel for gel electrophoresis.