Is there life in sea ice in the winter?
The upper two images show a low magnification cross sectional area of the lower 3 cm of sea ice with brine layers in regular distances (skeletal layer). Also visible are two little green speckles of diatoms frozen in the middle of the ice crystals on the upper picture to the right.  The lower four pictures are higher magnified images of diatoms and a dividing bacterium (epifluorescent image upper white dot picture in the lower right corner) in winter sea ice collected off Barrow, Alaska Transmitted light
Four diatom cells and particulates in a brine pocket under the microscope at -15 °C from winter sea ice of Barrow Alaska under transmitted light

Epifluorescent light
Identical picture under epifluorescent light. Due to the DNA specific stain DAPI cells of diatoms and bacteria (also visible as little dots) become apparent.

More pictures of sea ice using a brine channal simulator