1) "An ice floe is a floating chunk of sea ice that is less than 10 kilometers (six miles) in its greatest dimension. Wider chunks of ice are called ice fields." Source and further information: http://en.wikipedia.org/wiki/Sea_ice 2) " This kitchen service coincided with the station service controlling the condition of the ice floe and the presence of polar bears near the station. These tasks turned out to be very important, for in the course of the winter the ice floe produced crevices several times, but those crevices closed again. Moreover, frequent visits of polar bears regularly caused for alarm among the participants. " Source and further information: http://www.innovations-report.com/html/reports/earth_sciences/report-107631.html 3) "Habitat related ratios were put into the equation. Now, it was assumed that polar bears could only survive if they were supported by at least 20 patches of sea ice. This correlates to the actual domain of a single polar bear – about 500 kilometers squared3. When the amount of ice grew too small, a polar bear randomly died – representing a fight between polar bears that resulted in death." Source and further information: http://www.supercomputingchallenge.com/archive/07-08/finalreports/55.pdf 4) Further information: http://en.wikipedia.org/wiki/Polar_bear#Global_warming http://www.dailymail.co.uk/news/article-500424/Polars-bears-brink-Dont-believe-it.html "Polar bears in Canada's Arctic" http://www.abc.net.au/rn/scienceshow/stories/2007/1893380.htm "Polar Bears in a Warming Climate" http://icb.oxfordjournals.org/cgi/content/full/44/2/163 http://www.dailymail.co.uk/news/article-433170/Global-warming-sees-polar-bears-stranded-melting-ice.html