Rich harvest

[Wim van Egmond]

Sometimes you can find rich samples of Desmids. This is mainly Micasterias thomasiana.

Wim

[bernhardinho]

Hi Wim.

good gracious those are beautiful. Where on earth did you find these?


Bernhard

[beetleman]

They are very beautiful Wim. Like a microscopic field of flowers IMO.

[Wim van Egmond]

Thanks!

I think with photomicrography it is always nice to have many organisms and avoid detritus. So over the years I found out several ways to prepare my samples or slides so that it would be easy to make pictures with a nice collection of organisms, and no disturbing detritus. I am sure many of you use the same tricks but in case some of you don't know, many organisms move towards the light. Euglenas and other protists can be collected in swarms when they gather near the edge of a petri dish.

I discovered that when you have a jar with desmids (collected by squeezing Sphagnum moss, you can find desmids in marsh environment) and if you let it rest for a day the desmids will form dense groups surfacing the detritus. With the pipette you can collect them, without the detritus. For me the secret of microscopy is still the making of the sample and the right pipetting technique!

Wim

[Ken Ramos]

Indeed these are beautiful! There is a place that I know of where these things are plentiful or were anyway but it is quite a long drive from where I live to get to them. You're right about the light trick there Wim, it works very well for organisms that photosynthesize

[Wim van Egmond]

Ken, I also have to travel at least an hour to find the right habitat for Desmids. But I think it is worth the trip because the big advantage of the type of water where they live is that it will last for ever! Most desmids can be found in acid bog water. Because of the acidity it will not decay because of bacteria growth. So if you have a good sample you can keep it for a long time. I have some dishes (covered with a lit against vaporation, kept in a light but cool shadowy place) that still have a healthy community of desmids after a year!

When you go and look for desmids it is also good to know the waterplants that they often live on, like Utricularia, Myriophylletum and several other. Soggy sphagnum moss is also a good source for Desmids. I always look for the waterplants that full with green or brown growth and I squeeze the content in a jar. I also feel the sphagnum, if it is slimy it may contain desmids.

I copy the following from our dutch www.desmids.nl site:

Remarkably, the appealing, aesthetical cell shape of desmids very well fits the environment in which they use to occur. Desmids are hardly or not to be expected in polluted waters which, in summer time, grow turbid by mass development of other unicellular algal groups. Reason for that absence is (among other things) that, under nutrient-rich conditions, desmids cannot grow as fast as other algae, so lose in competition. In contrast to that, desmids have to be looked for in clear waters, preferably in those with a luxurious, submerged vegetation of aquatics. Most promising are also small pits and moss-covered shallows in fens and bogs. In general it seems to hold that the more delicate and diversified the structure of (semi)aquatic plant vegetation, the richer and more interesting the desmid flora connected to it. So, desmidiologists are recommended to visit (aquatic) sites of natural beauty!

Due to the dependence on clear, relatively nutrient-poor waters, in large parts of the world desmids belong to the seriously threatened groups of organisms. As most of the species only occur at highly specific combinations of habitat variables, they may be considered excellent indicator organisms. As a consequense of their high environmental demands, they are very useful in monitoring conservation value in (semi)aquatic habitats.

Sorry for the long text, but I thought it could be useful information.

Wim

[Ken Ramos]

Quite an interesting narrative there Wim, your observations of the environment in which the desmids occur seem to match those of where I find mine. The bogs, swamps, or as I often refere to them, wetlands, are at an elevation around 3500 to 4000 feet in the mountainous areas north of my home and have as yet to be affected by pollution, though I am sure if one looked hard enough though they would find evidence of mans carelessness. I find your remarks on the longivity of desmid samples to be quite accurate, though I personally never had given it much thought until now. However, I do remember bringing home a sample from the wetlands area here in the mountains of North Carolina and it was teeming with desmids and protozoa. The sample lasted for months as I recall and as I had placed it on a window sill with a northeastern exposure, I remember the desmid population becoming so thick the rim of the samples glass container turned a brilliant green.