That looks like a benthic rhodophyte like Bangia.

René

It is microscopic organisms photo taken in (100X magnification). I thing that it is nit Bangia sp.

I think it is not plankton, but a detached filamentous seaweed with epiphytes.

I am agreeing with Miguel Alcaraz. It is some part of a filamentous seaweed with epiphytes

Not a palnkton.. might be some other like seaweed/grass.

it looks like some Ulothrix (Chlorophyta) with epiphytic shell-building ciliates  

I'm with Willem on the loricate peritrichs on the filamentous algae.

A photo does not help to be able to identify clearly the species that can be in the ambience, it is necessary that you have more photos with better resolution and different perspectives to give you a better answer. Colleagues give different points of view and my point of view is that in general it is a species of seaweed or grass

 The photograph may be Bangiopsis subsimplex which  belongs to Rhodophyta, Bangiales. Bangiopsis generally occurs in mid littoral region of the  inter tidal rocky surfaces.  But not in the littoral zone. I have published some paper on this genus.