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For me observing the algae Stephanosphaera pluvialis has always been a very special, magic or majestetic moment...you understand what I mean if you ever had the change to observe them. I have shared a video in a previous post (look here if you are interested)

viewtopic.php?f=6&t=6205&p=56043&hilit= ... lis#p55976



Not only the algae but also the places where you can find this algae are sometimes very beautiful and majestetic. So would like to share you some pics from the old castle "Dragon Rock" were I collected the water sample with the algae in 2018:
















Water samples are taken from holes where rain water collects. For the development of the algae it is important that there a phases where the small ponds are get dry and permanent resting forms of the algae can survice:


The algae therefore has various "faces", depending on the stage of the development cycle it is. I still think very good overview is provided in this old illustration, what includes various stages of this algae

(http://www.biolib.de/gilg/high/IMG_0179.html)





The sexual reproduction of the green algae Stephanosphaera pluvialis takes place via gametes (aka microzoospores, isogametes, microgametes). See the details "D" - "H" in the illustration above.

The release of the gamets is like a "explosion of sperms" ... impressive to observe. Hopefully I was able to capture this somehow in the video that i took, it is a bit difficult to capture this moment.




The gamets later copulates and in theory they shall develop to aploanospores.

Some details on the gamets, seem they all have 2 flagellums:





Another photo I caputred a copulated couple of gamets, but with 5 (?) flagelums, what is somehow a anomaly (?)



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That is a spectacular location to collect such interesting samples! Thanks for the tour

Thank you 75RR for the friendly comment. Have a good day!

Wonderful presentation of this incredible creature and its habitat! I learned of Stephanosphaera i while ago from a beautiful photo Anne Gleich posted on Facebook. I immediately became obsessed with finding it and only grew keener when I read about its habitat. I've staked out a couple of abandoned red sand stone mines nearby (and some castles built from said sand stone). I really hope to find it one day.

Hello Viktor,
indead - Anne Gleich really makes phantastic photos! I press my thumbs that you will find the S. pluvialis. Another alternate would be that I sent you some resting aplanospores, so you can grow them on your side. But at the moment I am not convident that the cultures will develop well, in my dishes they are just looking very "poor", without much development. I am currently checking various light sources...

ImperatorRex wrote: ↑

Tue Jan 12, 2021 5:42 pm

Hello Viktor,
indead - Anne Gleich really makes phantastic photos! I press my thumbs that you will find the S. pluvialis. Another alternate would be that I sent you some resting aplanospores, so you can grow them on your side. But at the moment I am not convident that the cultures will develop well, in my dishes they are just looking very "poor", without much development. I am currently checking various light sources...

That is awfully kind of you! But right now, I'm looking forward to searching for Stephanosphaera as much as I look forward to finding it. It will be a very nice micro-adventure.

If I haven't found it in a couple of years, I might start to feel differently

Maybe not really spectacular, but maybe interesting for some of the S. pluvialis fans here in the forum after all?

Like Haematococcus pluvialis, S. pluvialis also develop permanent stages, so-called aplanospores. In this form, the alga survives longer phases in which the habitat has been dried out.
After rain it starts again ... few hours later the aplanospores "germinate" and several mobile, flagellated "zoospores" are formed through cell division. These "grow" within the "sporangium", at some point the shell of the sporangium can no longer withstand the "pressure" of the zoospores, the membrane shell breaks, often suddenly and unexpectedly, and the zoospores escapes.

The following is a sequence of images of the red H. pluvialis spores: 8 mobile zoospores have formed from the red aplanospore, which then "break out" of the sporangium:



The germination of S. pluvialis is basically the same process as that of H. pluvialis, however, according to my observation, mostly only 4 zoospores are formed or released:



Unfortunately I just missed the crucial moment of the birth and break out in the following short video sequence...but just!

Have missed this thread until today - don't know why...
Thanks for the interesting, beautiful and informative presentation !

Nice update

Lucky to catch as much as you did - bit of a lottery getting to capture the rupture at the beginning. You did really well!

Thanks from a S. pluvialis fan :)

Hi Hobbiest46 and 75RR,
thanks for your nice comments.

Very nice videos and information!

Thank you Luis Carlos.