Hope this is not a stupid question but I cannot get a definitive answer from the DNA guys here at Aberdeen or from published papers.

I have used 18RNS to do a marine eDNA survey.

Usually eDNA is a presence and absence of taxa measure but it occurred to me that with one of my highest One Taxon Unit counts being phytoplankton diatoms, with them being single celled organism would one OTU=one organism.

If not could someone explain why not?

also my target species is Macro Algae. the lifecycle phase has both diploid and haploid stages. would the assay generally read both of them as the same taxa as a Diploid parent. I am confused as I believe that being haploid it only has one set of chromosomes and therefore only half of the DNA? and that being so might it be excluded as not recognised if the thresholds for ID are set too high.