Please ID this for me

pwnell · Post by **pwnell** » Wed Sep 19, 2012 4:51 pm

40x * 2, DIC - from a freshwater pond in Surrey, BC, Canada. It moved forwards / backwards in the water column. Also, what are the colourful spots (I presume these could be minerals being polarized by the DIC illumination?)

Charles Krebs · Post by **Charles Krebs** » Wed Sep 19, 2012 5:39 pm

Looks like Cyanobacteria ("blue-green algae")

pwnell · Post by **pwnell** » Wed Sep 19, 2012 5:52 pm

Thanks Charles, but what are the colourful dots inside of it? I have seen many strands of cyanobacteria but never one like this.

phytoplankton · Post by **phytoplankton** » Wed Sep 19, 2012 6:55 pm

A fungal hypha perhaps? Was it unbranched?

When I see something I can't identify like this I tend to observe it in several lighting methods. I'd try phase, as well as various barrier filters in darkfield to see if it has any autofluorescence, polarization with various compensators, etc. Chlorophyll autofluorescence, for example, can be quite useful in narrowing down the choices to photosynthetic organisms.

pwnell · Post by **pwnell** » Wed Sep 19, 2012 7:39 pm

phytoplankton wrote:A fungal hypha perhaps? Was it unbranched?

It was unbranched, just like you see here.

phytoplankton wrote:When I see something I can't identify like this I tend to observe it in several lighting methods. I'd try phase, as well as various barrier filters in darkfield to see if it has any autofluorescence, polarization with various compensators, etc. Chlorophyll autofluorescence, for example, can be quite useful in narrowing down the choices to photosynthetic organisms.

I will remember that for next time. Unfortunately I do not have phase contrast, but soon I will have fluorescence.

phytoplankton · Post by **phytoplankton** » Wed Sep 19, 2012 8:37 pm

The colored dots may be birefringent droplets of lipids, or something like that.

To view autofluorescence in algae I use a broad spectrum deep blue excitation filter + an oiled darkfield condenser + a broad spectrum (yellow and longer wavelengths) barrier filter. It is adequate for strong autofluorecence in some species but not all. Epi-fluorescence is much better but all my filter cubes target certain fluorochromes and are too specific to view autofluorescence.

Charles Krebs · Post by **Charles Krebs** » Wed Sep 19, 2012 9:03 pm

Search around in the genus Planktothrix. There are some cyanobacteria in this genus that formerly were listed in Oscillitoria that look very much like you have pictured here (and I have seen from waters just a bit south of you.)

One possibility for example is Planktothrix rubescens.

Don't know what the internal spots are.

pwnell · Post by **pwnell** » Wed Sep 19, 2012 9:14 pm

Thanks Charles, that seems pretty much it.

phytoplankton · Post by **phytoplankton** » Wed Sep 19, 2012 9:16 pm

I think Charles is on the right track. This is where fluorescence could help in confirming:

http://kops.ub.uni-konstanz.de/bitstrea ... sequence=1

Cyanobacterial species use the biliproteins phycocyanin and allophycocyanin to harvest light for photosynthesis. Some species, including Planktothrix species, additionally contain the biliprotein phycoerythrin(Glazer,1985; Anagnostidisand Koma´rek, 1988). When examined under blue light excitation, phycoerythrin and phycocyanin ﬂuoresce orange and red, respectively. Therefore, cyanobacteria can be enumerated by visualising the autoﬂuorescence of phycoerythrin and/or phycocyanin using epiﬂuorescence microscopy (Walsby and Avery, 1996; Sieracki and Wah Wong, 1999).

pwnell · Post by **pwnell** » Wed Sep 19, 2012 9:19 pm

I have some homework to do! Thanks phytoplankton.

phytoplankton · Post by **phytoplankton** » Wed Sep 19, 2012 10:08 pm

Glad to help.

It seems we have similar interests. I am setting up to do marine aquaculture for aquariums, though I don't have any tanks setup at the moment. Your tank is beautiful. I love that Seriatopora caliendrum with the green tipped polyps.

pwnell · Post by **pwnell** » Wed Sep 19, 2012 10:31 pm

phytoplankton wrote:Glad to help.

It seems we have similar interests. I am setting up to do marine aquaculture for aquariums, though I don't have any tanks setup at the moment. Your tank is beautiful. I love that Seriatopora caliendrum with the green tipped polyps.

Thanks for the kind words. I like that coral most when it fluoresces: http://www.waldonell.com/reef/reefpage/ ... ence/?rp=2