It is very difficult to recognize any diatom species by looking at the girdle view of the cell, such as your photograph shows. Yes, girdle bands views are used in EM but when you are absolutely sure that it belongs to a specific species you are observing in valve view. You should always look for valve view of diatoms and present also measurements of he cells.
Dear Anila, you can say little more than it is a pennate diatom and I would not be so bold as to plump for Navicula from the image given. As has already been said you should identify the diatom by observation of the valve face and not the girdle bands. I can make out striae on this diatom of which there seems to be approximately 10-15 striae in 10 micrometers. The number of striae alongwith other defining characteristics of the valve face is required for taxonomic assessment.
I agree with Dr.Kevin regarding the number of striae and its significance in the identification of diatoms. My suggestion on your photomicrograph is that it could be a species of Pinnularia.
It is a species of Pinnularia. But to identify the species you should take valve views in DIC or phase contrast and took several pictures of that species from the same sample to decide its size range which is also a criterion of diatom species identification.
Dear Anila, this is pinnate diatom. but impossible confirm in species level. because need for breath and length measure of calibration. tell me about the dia or length.
Always try to have proper diatom slides prior to investigation. Looking to native material is quite informative but the proper diatom taxonomy is always performed on permanent slides for LM or special preparation for EM!