Coy Mistress - Shifting tones as crucial to the central claim

In Marvell's "To His Coy Mistress" the subject of the poem is easily discovered: Seize the day, embrace the present beauteous states of life before it's too late. In each stanza Marvell employs a distinct change in tone to strengthen this point. In the first stanza the tone is a more light-hearted one. We find a lot of uplifting and more positive and gentle language. For example he speaks of rubies, the tide, and a growing love. The nature of the senses are explained in a delicate way. For instance "thy forehead gaze" and "two hundred to adore each breast." The first stanza is all about a present love, one which is growing and adored. The tone of the second stanza is a drastic change from the first. The first word "But" signals this important shift. Language starts to deteriorate as Marvell makes the point that nothing (beauty, love, virginity) lasts forever. There is a mention of deserts, a beauty that "shall no more be found," of a vault, worms, a "quaint honor" turning    "to dust", and finally ashes and the mention of a grave. Marvell states that "none there do embrace." He has taken the reader on an emotional roller coaster at this point. We land at the final stanza beginning appropriately with "Now therefore" which seems to be an urgent resolution. Marvell brings in both tones from the preceding stanzas. He states "while the youthful hue sits on thy skin like morning dew and while thy willing soul transpires at every pore with instant fires now let us sport us while we may." So here we see a mention of a gentle "youthful hue" alongside with a "fire" which is a direct merging of the two tones. The urgency of seizing the day comes with diction such as "Prey,"  "time devour" and "tear our pleasures with rough strife." Marvell's last sentence is a fitting way to end his poem as he encourages the reader to take advantage of all the aforementioned bright qualities of life before its too late. Carpe Diem. It is clear that Marvell's use of tone completely strengthens and reinforces his central point and the poem would absolutely be weaker without these shifts.