[Annelida] Re: benthofauna
(by procesoecologico from yahoo.com)
Sat Aug 9 16:52:32 EST 2008
Apologies by my extended mail,
I do not refer to encapsulated stages of resistance, but to live organisms. I repeat that I have insured myself of avoiding all kind of contamination, only later I have investigated on similar reports and am consulting other colleagues on this aspect that seems to me to be very interesting though rather disconcerting.
It is true that the known they are the encapsulated types that appear under certain conditions, but what I have found are adult organisms that after washing the sample for the first analysis or re-analysis (the first time happened to me), within a few minutes I saw in some cases nematodes in other marine mites moving in the plates of analysis.
If there was contamination by water with nematodes or other organisms I could have verified it with the analyses that I did repeatedly for two years (when I had the first observation), only I have detected rotifers that really they might generate confusions and induce to mistake if it is that the precautions do not take. It is very difficult that another type of organism could enter since I have used only distilled water and free of impurities, I did the chain of custody-like control in the plates, made sure of not contaminating the sample with the instruments, etc.
I have taken charge searching from microfauna till macrofauna and have not found organisms in the containers of laborator water except which already I indicated, in addition the water filters, so there are many impediments for the revenue of live organisms from another environment. Now, something that I forgot to mention was that, for example, in case of the sample of benthic meiofauna of 2003 re-analyzed (for other motives) in 2006, I never washed the sample but I put part of the content (that was possessing formaldehyde) in a clean plate of analysis; in fact, the smell was strong … in that opportunity I found ONLY THE UNIQUE MARINE MITE that I registered years behind (I corroborated this with my notes and really in that sample only I had a marine mite to enclosed which I measured to estimate biovolumen), so that was very strange… later already it was not so much.
If still we believed that there is contamination, on the one hand there would be necessary to presume that this first specimen was a terrestrial mite, which tolerated the Rose Bengala tint that I applied before the re-analysis and that was kept in that concentration of formaldehyde (10 % in distilled water) for TWO DAYS and that, it is clear, was not so terrestrial since always it was in movement without problems at the bottom of the plate. The posterior experiences (except one where it was again a marine mite) were almost exclusively with nematodes. I can say that, in whole, of several dozens of samples analyzed till now, only I have found near 10 live organisms, which is certainly very negligible but not stops being interesting as observation.
My samples are of the Humboldt System, off central Peruvian coast, OMZ intense, high sedimentation of organic matter, normally reduced conditions on the bottom, on two stations located to 50 and 100 m.
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