At the end of the year Poem by William He

" Dissolved oxygen" : Dissolved Oxygen is the amount of gaseous oxygen (O2) dissolved in the water. Water temperature and the volume of moving water can affect dissolved oxygen levels. Oxygen dissolves easier in cooler water than warmer water. " Siren" : In ancient Greek mythology, a Siren is a hybrid creature with the body of a bird and the head of a human. Sirens are traditionally understood to be female, but similar figures with beards can be labeled either as Sirens or as daemons. Sirens are dangerous creatures who live on rocky islands and lure sailors to their doom with their sweet song.