Chapter 19

The surface of a rock in a flowing stream will often contain a biofilm. What advantages could be conferred on bacteria growing in a biofilm compared with growth within the flowing stream? (Section 19.4)

In what soil horizon are microbial numbers and activities the highest, and why? (Section 19.6)

Many pelagic prokaryotes can use light energy but are not considered "phototrophs" in the same sense as cyanobacteria or purple bacteria. Explain. (Section 19.11)

What is the difference between piezotolerant and piezophilic bacteria? Between these two groups and extreme piezophiles? What properties do piezotolerant, piezophilic, and extremely piezophilic microorganisms have in common? (Section 19.12)