Investigation into microbial communities, viruses, and other microorganisms is central to marine biology. Bacteria make up 98% of the ocean's biomass and plays a central role in the ocean's ecosystem. Marine microbiology is now more important than ever as a means to understand the relationship between various organisms in the ocean and the effects of climate change.
Microscopy is fundamental to studying the tiniest organisms that make up such a vast portion of the ocean's environment. Correlative light and electron microscopy (CLEM) provides a new dimension to the study of marine microorganisms by offering a simultaneously more holistic and detailed picture of microorganisms at the nanoscale.
Biodiversity is one of the central topics in the field of marine microbiology. Combining a fluorescence with an electron microscope enables the researcher to study the relationship between different organisms and viruses in the marine environment. CLEM also opens up new possibilities such as the in-depth investigation of thin sections.
Figure 1: Overlay of fluorescence and electron images of microbes in the marine environment.
Correlative light and electron microscopy (CLEM) offers the possibility to get the most out of your marine sample:
Understanding the dynamics of marine environments means understanding how microbes, protists, and viruses relate to one another. This makes CLEM an ideal tool for marine microbiologists; combining the labelling power of FM with the highly detailed contextual information offered by EM. FM serves to illuminate specific regions, while EM reveals the whole picture and the morphology at a nanoscale resolution.
As a case in point, Jahn et al. used correlative light and electron microscopy to study marine sponges. A large portion of the biomass of marine sponges are microorganisms. The researchers were able to identify Poribacteria cells within the sponge microbiome using the red nucleotide stain DAPI and the Poribacteria specific 16S rRNA probe POR1130. The authors argue that the correlation of data from different microscopes enabled “the simultaneous identification of specific microbes at high resolution in their environmental context, the study of their cellular structures, and the localisation of target proteins.”
The SECOM, an integrated CLEM system, enables the scientist to obtain two different types of data simultaneously. There are thus no changes to the sample between measurements and the data can be overlayed with complete accuracy, requiring no intervention from the researcher.