Pond life?

ChrisR · Post by **ChrisR** » Fri May 25, 2012 5:19 pm

I seem to have got involved in fund-raising to improve some ponds in my local park. Many of them are silted, clogged with alien invasive plants, etc.

Plants and visible bugs, I can handle.
If I can help to show the effects on the micro- biodoversity , then that would help our argument.

I have a basic Olympus CH2, with its simple bulb/condenser, though I've not used transmitted light. It's not binoc or a trinoc, just a camera body on the tube.

To the pond-dippers out there, does this seem to be a reasonable venture, or are the learning curves and technical challenges rather steep?
I would need to
1) find out about what should be in there ( or compare with our better ponds)
2) find a way to do a reasonably scientific survey
(those two I anticipate I can learn fairly quickly)
then
3) learn to drive the hardware I have. I won't be investing in phase or DIC equipment. Would it be adequate?

4) come up with meaningful results

.

( I have visions of potential donors not being impressed with water-fleas and things which look like bacteria associated with cholera, but that's another issue!)

BJ · Post by BJ » Mon Jun 11, 2012 10:52 am

Chris,

if you have not seen it, this article may be of interest:

http://teesvalleybiodiversity.org.uk/wp ... vation.pdf

...a rather long url. It does suggest that monitoring diversity of just two groups may reflect overall diversity. Perhaps an achievable objective.

Good luck with your muddy holes

boa sorte
Brian

johan · Post by **johan** » Mon Jun 11, 2012 1:01 pm

Interesting, so caddisfly and damselfy larvae are the indicators of pond diversity. Of interest to me because my garden has 2 ponds in it, one for goldfish and one that's been left to naturalise. After less than one year, it's fascinating that the non fish, naturalised pond has *infinity* more life in it than the one with the goldfish. I keep meaning to take macro images of some of the larvae & beetles, but there are just not enough hours in the day.

descall · Post by **descall** » Mon Jun 11, 2012 2:46 pm

Hello ChrisR,

There are a range of standard methods for surveying ponds in the UK, some with a strong focus on aquatic invertebrates. See the Pond Conservation website for further details:
http://www.pondconservation.org.uk/Surv ... symmethods

Some of these will allow you to measure the relative quality of your ponds against benchmarks.

Best wishes,
Des

ChrisR · Post by **ChrisR** » Wed Jun 13, 2012 8:35 am

Thanks all for replying, I'd missed that there were responses.

Yes I'd found PondConservation, in fact they're after "our" (Richmond Park) support for their application to the Lottery for a grant to teach US and get US to do surveys for THEM!
The PSYM methods look good in that they're standardised metrics and have two levels, PC will analyse a test-tube for £15, though I don't know how frequently that's necessary.

What I'm less clear on is how you actually get to look at the "invertebrate assemblage".
Down to tadpoles, I can see. Below that, is unfamiliar.
I've only ever used incident light, metallurgical microscopes, and mostly in the past, for flat subjects I'd spent hours preparing.
What do you do - poke about in a Petri dish with a low power binocular?
What range of mag would suit - most of the low power scopes like this (ebay 150831031188) one seem to start at 20x, or 10x minimum.

That seems a bit too high a magnification for just-visible things.
Can one put a small P&S camera on one eye and an eye on the other?

I have a cheap old dissection scope with odd-length objectives, fixed 10x I think..
I've a couple of Olympus CH microscopes I could put back together, having cannibalised them! And probably a condenser somewhere.
I haven't used transmitted light since college.

ChrisR · Post by **ChrisR** » Sun Jun 17, 2012 1:17 am

After a prompting from Alan W I attended a Quekett Microscopical Club event at the Natural History Museum, which was intended to introduce kids to pond-dipping.
I found it very useful to be able to both quiz everyone there, who gave generously of their knowledge, and play with microscopes from £5 to £5000.
My thanks go to all concerned.

For my purposes a stereo scope with an ability to pop a small camera on one eyepiece (afocal?) will suffice I think, for identifications and portability.

It does seem that getting LOW enough magnification is more of a problem than high.
How large a field of view could I get with a camera on a stereo scope?

rjlittlefield · Post by **rjlittlefield** » Sun Jun 17, 2012 10:29 am

ChrisR wrote:How large a field of view could I get with a camera on a stereo scope?

My 10.5X-45X zoom scope has a maximum field diameter about 21 mm. The full width, but not the full height, is easily captured with a Canon SD700 IS zoomed clear out and positioned touching the eyepiece. Zooming closer and hardmounting would be a problem because of lens extension issues.

--Rik

Cactusdave · Post by **Cactusdave** » Sun Jun 17, 2012 10:37 am

Missed you at the Quekett event on Saturday sorry to say. I was in the back room manning the microscope which we were using to show our 'catch' on a big TV screen Some really bright kids at the Young Scientist session. A real pleasure to talk to them and show live pondlife to on the 40" screen. Feel free to turn up at any Quekett meeting at the Natural History Museum. Several contributors from here usually turn up and there are always people to advise on microscopes, critter ID etc.

ChrisR · Post by **ChrisR** » Sun Jun 17, 2012 11:56 am

AH, I was looking at the stained pollen on that!
I'll be joining. There's an (annual?) outing to Wimbledon Common which is also very close to me. Might see you there

ChrisR · Post by **ChrisR** » Sun Jun 17, 2012 11:59 am

My 10.5X-45X zoom scope has a maximum field diameter about 21 mm.

Ah thanks
Another "magnification gap" rears its head then. Something about 10mm wide falls through

rjlittlefield · Post by **rjlittlefield** » Sun Jun 17, 2012 12:11 pm

Depends on what you mean. That's 21 mm at 10.5X. Field width is 10 mm at 22X, and so on. I can dial in whatever I want, down to 5 mm at 45X. I'm not sure what happens to the NA. It's pretty small in all cases, giving good DOF but not so great resolution.

--Rik

ChrisR · Post by **ChrisR** » Sun Jun 17, 2012 4:36 pm

I mean subject-side.
A compact ( I mean my compact(s)), covers alligators, and down to about 20mm field width, then there's a gap until the microscope starts, at about 2mm.
There are 5x eyepices - they don't cover 20mm or so I think? (4mm subject side)

A T2 adapter and objectives 1x to 6x are available for one popular low cost range ( Brunel). So an option would be to use a DSLR for 20 to 3.x mm. I think!

But, I was trying to keep it simple, and one camera.
A camera, bellows and slide copier would do it, but not ideal to trug about with at pondside.

Would only need to be good enough to show on a screen for id, or print quite small in a news sheet.

rjlittlefield · Post by **rjlittlefield** » Sun Jun 17, 2012 5:08 pm

When I say "field width", I'm talking subject side too. Here's a scale with millimeter ticks, with the microscope zoomed out to its 10.5X setting.

--Rik

ChrisR · Post by **ChrisR** » Mon Jun 18, 2012 4:22 am

Oh I see, I think. Not what I expected. Sort-of comparable to a 10.5x loupe.

That would do for many of the surface swimmers, etc.

This is with the eyepiece, yes - so a "5x" eyepiece would have a wider, if not double, fov?

Are we on the same page.., like eg
http://www.brunelmicroscopes.co.uk/cata ... page13.pdf

rjlittlefield · Post by **rjlittlefield** » Mon Jun 18, 2012 7:01 am

Pretty much like that, except that my scope is an ancient student version of the Bausch & Lomb Stereo Zoom 4 or something very similar. The magnification is continuously adjustable and the eyepieces are fixed.

--Rik