âI think weâve read every single book they have.â Mark chuckled. He still wasnât ready to put the children downâWill was hanging off of one hip, his hand on Markâs shoulder as he stoically looked down at Bridget, and Mabel had nuzzled into the crook of Markâs neck with a contented sigh.
Diatoms are producers within the food chain. A unique feature of diatom cells is that they are enclosed within a cell wall made of silica (hydrated silicon dioxide) called a frustule. These frustules show a wide diversity in form, but are usually almost bilaterally symmetrical, hence the group name.
(Bacillariophyta), a division of algae comprising about 20,000 species. Diatoms are microscopic (0.75-1500 microns), unicellular, and solitary or colonial algae.Among the colonial forms are species that live in slimy pipes, forming brown clusters that reach 20 cm in height. Diatom cells have hard siliceous shells (frustules) consisting of two overlapping halves or valves.Bacillariophyta), a division of algae comprising about 20,000 species. Diatoms are microscopic (0.75-1500 microns), unicellular, and solitary or colonial algae.