The annual variation in CaCO₃ particles and chl <i>a.</i>

<p>Samples were collected at 5 m depth in Raunefjorden, a coastal sampling station south of Bergen, Norway. A) Calcium in the coccolithophore <i>Emiliania huxleyi</i> and in Ca particles estimated from scanning electron microscope counts. B) Total particulate Ca concentration measured by X-ray fluorescence (error bars are SE, n = 3–4) and chl <i>a</i> concentration. Hydrographical data and chl <i>a</i> profiles are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0047887#pone.0047887.s004" target="_blank">Fig. S4</a>.</p

Scanning electron microscope images of marine calcium particles with different morphology.

<p>Samples were collected at 5 m depth in Raunefjorden, a coastal sampling station south of Bergen, Norway. A and B) Particles resembling bacteria and microcolonies of bacteria. B and D) Particles similar to the Ca carbonates described to precipitate on the cell surface of cultured marine bacteria. E and F) Particles with one flat surface suggesting that they are formed on a surface or interface. G and H) Particles with rhombohedral shape. I and J) Baton like particles resembling Bahaman ooids. All scale bars are 2 µm except in d) where it is 1 µm and f) where it is 10 µm.</p