Skeleton On The Sea Floor -- revision

[Donald Q.]

Her skeleton just appeared there one day, fused to the seabed, I think 'her skeleton' is too much too soon. 'It just appeared..' was nice, I think, although you can make 'the skeleton' work maybe? 
as one clinically depressed merges with their mattress Still like the depressed / mattress link 
or decomposes into couch cushions.
Half her bones already lay concealed in the silt, I don't think you need both 'already and 'lay' , feel like each word gets in the other's way
like puzzle pieces disappear down the sides of a chair Tense clashes with previous line a bit
or underneath a love seat. Her breastbone shattered I think chose one between chair and love seat and run with one. I love the comparison between the sand and the sofa gap abyss .
from the ocean's pressure, leaving her ribs to reach up Cool image
in wonderment at its absence. The weight
of the water fell over her face like a thick blanket Don't think you need 'fell over' .Fewer / different words could work better for the flow of the line i think 
as she slept, convincing her mind to keep dreaming
and her lungs to surrender.

She just appeared there one day,
a woman of thirty-five, feet strapped Good use of strapped 
into sensible brown heels, and settled
behind a desk with a picture of a husband and two kids,
unable to breathe.

Just a few pointers, glad you are working on this poem there's some really good stuff here that you are starting to bring to fruition.