RESEARCH UPDATE: Identifying bacteria in TNT contaminated sediments

Every gram of North Sea sediments is home to a vast variety of marine bacteria. Some might be useful to indicate the presence of explosives leaking from shipwrecks and dumped munitions. Researchers at the Flanders Marine Institute are trying to find these bacteria with molecular biology techniques, using sediment samples collected over the past year (for example, in the German Bight, or at a Belgian wreck site).

First step in identifying bacteria in the sediments is to extract their DNA. This is done by a machine which is vigorously shaking the sediments, so that bacterial cells burst open and release their DNA. After separating the DNA from the sediments, any contaminants like salts, that can impair later steps in the analysis, are being removed. Additional tests are made to check for the quantity and quality of DNA. If the tests are successful, the DNA is further prepared for the last step of molecular analysis: A special gene, which is holding unique information about the bacterial species (16S rRNA), is amplified and identified through a chip (nanopore) that is able to read each DNA fragment in the sample. Finally, the data is compared with databases about bacterial genes, which enables researchers to identify what bacteria are present in the sample. Relating the information about bacteria to measurements of TNT in the sediments will show which bacteria can be found more often in TNT-contaminated sediments.

Cover: © Klara Liebrecht, AWI 2024. All rights reserved.