Floscularia Ringens... "another brick in the wall"

Charles Krebs · Post by **Charles Krebs** » Sun Jun 05, 2011 7:00 pm

phytoplankton,
In this case it was a 20/0.70 "dry" (referring to the objective used in a video section... the top still photo here was a 60/1.40 "oil"). The problem with a subject like this is that in order not to "flatten" it, and to observe somewhat natural behavior you need to give it some room. This current specimen was quite a bit beneath the coverslip, so there was more water than I would like between the cover and subject. These high NA objectives lose something (at least my 20/0.7 does) when you focus that deeply into a wet mount. (While an "oil" might be a bit better, there is still the difference in refractive index to mess things up).

The last shot was from a specimen I photographed a few years back. In that instance I was lucky enough to have the rotifer very active but staying "fixed" in an excellent orientation and very close to the cover slip. It's not all that often that everything works out that way!

discomorphella · Post by **discomorphella** » Sun Jun 05, 2011 8:47 pm

Hi Charlie,

Great video and stills. Where did you find the rotifer? I've been looking around my ponds but haven't found one yet.

David

Charles Krebs · Post by **Charles Krebs** » Sun Jun 05, 2011 9:56 pm

David,

Where did you find the rotifer?

I found just this one in a pond here in Issaquah. It was attached to a Duckweed "root-hair". My old sampling pond (can't access it any longer

) would be chock full of these this time of year. There I would find them on Duckweed as well, and also in large numbers on small grass blades at the waters edge.

Francisco,

What power is the Led?

It is a Luxeon K2 (5 watt?). But it is only being driven at 1000mA with a BuckPuck. At the time I put my flash "module" together (about 4 1/2 years ago) it was a good option. It has worked flawlessly during this time. Now there is much more to choose from in regards to LED components, I need to take a look at what is out there.

I'm open to suggestions!

phytoplankton · Post by **phytoplankton** » Sun Jun 05, 2011 11:48 pm

Charles Krebs wrote:Francisco,
What power is the Led?
It is a Luxeon K2 (5 watt?). But it is only being driven at 1000mA with a BuckPuck. At the time I put my flash "module" together (about 4 1/2 years ago) it was a good option. It has worked flawlessly during this time. Now there is much more to choose from in regards to LED components, I need to take a look at what is out there.

I'm open to suggestions!

The K2 is about 3 watts, IIRC. I just converted my Orthoplan to led and I like the Cree MC-E I used. It uses about 9.5 watts so a sufficient heatsink is required. With a 700mA buckpuck it produces roughly 750 lumens (versus 200 for a K2 at 1000mA). But it is a 4 chip design so if you want a tighter source or don't want the cross shaped pattern of the mount you should go with a single chip LED. The cross pattern of the MC-E mount sure makes it obvious when Kohler illumination isn't established.

If I had to do it again I would use the new Cree XM-L. It is a single chip LED that can produce 900+ lumens when driven at 3000mA. You couldn't use a buckpuck and you'd need a beefy heatsink.

Of course I'm an extreme amateur so I'd let some more experienced people weigh in before giving my comments too much credence.

Cactusdave · Post by **Cactusdave** » Mon Jun 06, 2011 12:24 am

Wonderful images. This particular Rotifer has inspired and delighted microscopists since our illustrious Victorian predecessors. I can well imagine the awe and pleasure of one of those distinguished bewhiskered gentleman if we could show him Charles' pictures, and as for the video, that would truly make his whiskers curl.