You didn't italize or mark the phrase, but I see one good candidate:
"The circus animal trainer" is in a way another name given to Mervin, a kind of "renaming" him: this is called an appositive phrase, so if this was the phrase appositive phrase is the answer! (also, I don't see the other phrases here).
Answer:
These 2 sentences are Homograph
Explanation:
The given two sentences are example of Homographs.
Homographs have word with the same spelling but different meaning.
Here the word bass in the two sentences is spelled in the same way but it carries different meaning in the two sentences.
While a Homophones has same sound (no same spelling) but different meaning . Homonyms can be either homophones or homographs, or both
It affects the story because it allows the readers to know how the author feels towards the following and it also allows the readers to consider what he is thinking.