Hi, Mohammed, it depends what member of plankton is investigaed. It can be of macroplankton mainly represented by animals and guiding by Zoological nomenclature, microplankton - animals and protists, so Protistological nomenclature, nannoplankton, pikoplankton etc. As well you have to do with microalgae... Description of species can do only highly qualified specialist in Journals or books that belongs to the spectrum of the same branch of science. So, if you suppose smthng interesting should ask him for help. Anyway you may be have scientific adviser that can explaine you these things.
You can compare with identification keys. Use a taxonomist or museums helps. Genetically Sequencing if possible, and publish a paper. For scientific names you should find the genus at first, then choose second name of the species. Species names can be repeated between genera (so lots of genera have a species termed 'magnus' for big or 'annectens' for different etc.), but genera must be unique. Note that often the media reports the naming of a new species, when in fact a new genus is being created. It may be that a new species is being erected to go into that genus, but it may also be that a species is being taken out of one genus and placed in its own genus.
Finally, this description and data must be published in some form that is internationally accessible and archived in multiple locations. Until recently this meant getting papers into established public or academic libraries in multiple countries, but now electronic publication of names is permitted making things faster and easier. Oddly though, peer-review is not a requirement of identifying names and this can cause problems through those who deliberately or accidentally flaunt the conventions of naming and create names that cause confusion, not solve it.
1. compare the morphology of your specimen with referenced photos for plankton until reach to the closest photo to your samples ( must there websites or books relate to this topic).
2. DNA isolation and make a sequencing
3. analysis the sequence by using bioinformatic software to make alignment with other plankton sp. to determine the similarity as well as build the phylogentic tree to decide the type of your sample
4. you can record it as a patent if you use it in application for first time
5. you can use NCBI to create the accession number
note: i think you may search in PubMed (Database) about Plankton to get information about all plankton discovered.