The researchers used a method called signature lipid biomarker analysis to study microbial mats, which are communities of bacteria in sediment. This method helps to identify and quantify different bacterial populations in the mats. Traditional methods could only reveal a small fraction of the microbial diversity present. By analyzing the lipid components of the mats, the researchers were able to understand the physiological activities, daily and seasonal processes, and different environments within the mats. This approach, combined with analyzing nucleic acids from the lipid extraction, provides a powerful tool for studying complex microbial communities like intertidal microbial mats.