Hi Muhammad,

I think that it is possible because there are very few microbes in your special sample (sediment from Glacier). When I extracted DNA from sediment of estuary, 0.5g wet sediment for each sample using OMEGA soil DNA kit, I only obtained less than 10ng/ul when I eluted by 50ul ddH2O. So in your extreme environment, the glacier sediment, it should have very very few microbes. I suggested that you may increase the weight of your sediment when you extract DNA. You can choose a proper kit (e.g. Mobio DNA kit series, some kits may be up to 10g samples when you extraction) to achieve this. 

Hope it helps

Guangshan

thank you @Guangshan for valuable input.

Besides the sediment ratio problem what other factor is most important? and do you have any experience regarding FastPrep Soil Kit MP Biomedicals?

As far as I know, the content of humic acid and salinity may be important factors. But I still think it may be your samples with less microbes. I have not used the FastPrep Soil Kit before, so I'm sorry for that. You can also see some references to learn their methods. Below link is an example including DNA extraction from glacier sediments, they used Mobio kit, which you can try it in your study.

Hope it helps,

Guangshan

http://femsec.oxfordjournals.org/content/femsec/91/12/fiv144.full.pdf

Thank you @Guangshan for the must appreciated help.