How did the character transform in "Diving into the Wreck"?

The main character in this poem is also the speaker. She begins the poem feeling anxious about the deep sea dive she is about to undertake. She says, for example, that she is having to dive "not like Cousteau with his / assiduous team . . . but here alone." As she descends into the water, the speaker also remarks that her "flippers cripple" her, and she reflects again on the fact that she is alone, with "no one / to tell (her) when the ocean / will begin."
Towards the end of the poem, however, the speaker transforms in that her anxiety is replaced with wonder, fascination, and a sense of calmness. She is almost bewitched by "the treasures that prevail" at the bottom of the sea, and she becomes completely at one with the time and place. "This is the place," she says, "And I am here." She also thinks of herself as "the mermaid" and "the merman." In other words, she feels that she belongs in this place and is in harmony with it. This is in stark contrast to the speaker's state of mind at the beginning of the poem, when she contemplated the dive ahead with trepidation. By the end of the poem, the speaker is much calmer, even though she is surrounded by "the ribs of the disaster" and "the tentative haunters."