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  • Writer's picturemariagross

Tiny green translucent globules

On July 11th, Zone 7, grid #1751 (Wiley Brook,) I found a growing clump of Native milfoil and realized that many had green translucent globules scattered throughout.

Correspondence with both Amy (re: Plants) and Amanda (re: Cyanobacteria) at NH DES led to the mutual decision to stand by and wait to see if the quality of this might change.

Amy recognized it as Ophrydium versatile (a colonial microscopic single-celled protozoan) and we had found this last year as well at other sites on Conway Lake. But then seeing these same type of light green translucent blobs late last season, appearing larger and actually free floating, led us to take the samples to Amanda for analysis. Using the microscope she discovered it was Rivularia, a low toxic cyanobacteria.

I guess the next question is whether Ophyrdium can turn into a cyanobacteria, like Rivularia. I will ask Amanda and post an update.

This site describes the protozoan with more information:

Ophrydium cells reproduce by dividing … The individual cells line up side by side in the “blob” and attach themselves to a jelly-like substance they secrete. They are symbiotic with microscopic Chlorella algae which live inside the Ophrydium cells and give the blob its green color…. Ophrydium is always found with its algal symbionts…. As the number of Ophrydium cells increase, they remain on the outside of the growing blob, and the interior, which is now empty of Ophrydium cells, becomes a watery gel. This soupy interior gel can become home to all kinds of microorganisms such as mastigotes, euglenids, chlorophytes, heliozoans, diatoms, bacteria, rotifers, nematode worms, other ciliates, and even tiny crustacean copepods, leading some to compare Ophrydium blobs to a floating zoo of tiny creatures.

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