Final answer:
Light microscopy may not reveal all microorganisms in soil samples and the 'goo' from degraded polyurethane due to visibility limitations. Techniques such as Gram staining, fluorescent dyes, and confocal microscopy are often utilized to better observe and identify microbes.
Step-by-step explanation:
The technique of using light microscopy to examine soil samples and the 'goo' from degraded polyurethane is a common microbiological method. However, it may not allow observation of all microorganisms present due to the limitations in resolution and contrast provided by light microscopy. While some microorganisms and biofilms may be clearly visible, smaller microbes and those with poor contrast against the background may be difficult to discern.
To observe cellular and metabolic properties of microbial isolates, Gram staining is often used, as it provides contrast by staining bacteria differently based on their cell wall composition. For non-culturable prokaryotes, techniques such as Fluorescence In Situ Hybridization (FISH) could detect their presence by binding fluorescent probes to DNA within cells.
Confocal microscopy overcomes some of light microscopy's limitations by focusing on one z-plane at a time, producing a clearer three-dimensional image of thick specimens like biofilms. Techniques that enhance visibility, like darkfield microscopy and the use of fluorescent dyes, may be necessary to observe certain microorganisms effectively.