THe sample is a lake with 23725 µS/cm conductivity
pH 8,85
alcalinity 178,20 mg CaCO3/L
FIXED WITH LUGOL
size more or less 28 x 15 microns
i think that perhaps could be a raphydophyceae ( Chattonella ?) or perhaps a Chromulina ???
In photo m1 one of them is eating a Amphora.
Thanks in advance, any idea can help me
Maria
Dear Maria, from your formalin-fixed photos it is - for me - impssible to make an identification. As Maria Van Herk mentioned, chloroplasts are not clearly visible, the particles may be chloroplasts or stained reserve material. Chromulina and all other ChrysophytesI know, have only 1 or two chloroplasts, whereas Raphidiphytes have many. From the shape it looks like the aberrant dibnoflagellate Oxyrrhis marina - without chloroplasts, which feed on bacteria but also on small algae. It may occur also in very brackish waterrs. Oxyrrhis has the typical dinokaryon, with permanently condensed chromosomes. Ciliats, as Lucineide suggests, have makro- and mikronucleus. Thus nuclear staining may help in excuding either Oxrrhis or ciliates.
I recommend live observations, than the presence and absence as well as the number of chloroplasts (1 or 2 versus many small ones) can easily be decided.
Photos of Oxyrrhis you may find in :Hoppenrath et al. (2009) : Marine Phytoplankton. - Kleine Senckenberg Reihe No. 49 -E. Schweizerbart'sche Verlagsbuchhandlung Stuttgart.
Thanks you Malte for your comments, Oxyrrhis is a possibility!
Maria
Dear Maria verdugo althöfer, I think this is a Raphidophyceae. It looks like a Chattonella or a Gonyostomum. Good luck!
Thank you Mauro,.
When i saw then my first idea was Raphydohyceae ( Gonyostomum not because i used to saw they) but after the comments from Malte Elbrächter i am not sure because they really looks like Oxyrrhis.
.Something is sure they are heterotroph.
best wishes
Maria
Dear Maria,
as I suggested, Oxyrrhis is only one possibility, please check by nuclear staining, but be aware, that also raphidophytes have a large nucleus, but without condensed chromosomes. Raphidophytes sometimes present the same shape as shown on your photos. What about the habitat ? Is it an inland freswater lake with encanced conductivity or is in connection with marine environments. This would be interesting for the distribution of Oxyrrhis. What is the proof, that your organisms are heterotrophic ?
Thanks for your informations.
All best wishes
Malte
Dear Malte,
The lake is temporary , the typology of the lake is Interior in basins of sedimentation, of fluvial origin, type flatness of flood, high or very high mineralization. Much modified.
it is 10km away from the estuary, it is possible a connection wiht marine environments.
At this moment is has no water. The phytoplakton has a high variabilty between months and years. (a high relation wiht rains)
At the sampling the conductivity was 23725 µS/cm. I think they are heterotrophic because i found some of them with small diatoms inside.
Thanks
Best wishes
Maria
Dear Maria,
thank you very much for your information. Concerning the nutritional status : also species with chloroplasts can ingest diatoms or other food items.
If you still have fixed samples, I would appreciuate to get a subsample for staining the nucleus. For Oxyrrhis it is a strange habitat and it would be very interesting to veryfy its occurence in this habitat..Thank you very much.
Malte
Dr. Malte Elbrächter
Wattenmeerstaion Sylt
Hafenstr. 43
D-25992 List/Sylt - Germany
- Badges
- Science topic