a tube dwelling marine diatom (two additional pictures)

[Franz Neidl]

This marine diatom is living in mucilage tubes which are forming dens tufts, 2 - 5 cm in high. They may easily mistaken for thalli of filamentous Phaeophyceae.
The mucilage tubes were attached to the stones at one end while the other end was floating free in the water. In this way the algae are not lying flat against the sediment surface, but the individual cells are oriented with their longer axes perpendicular to the sediment surface.
Within the tubes the diatoms were moving.
I dont know the species. Maybe somebody can help me.
Obj. 20X DIC

Franz

[Jan Kros]

Hello Franz
Kenn you tell me the mesurements of these diatom?
It seems likely to be Amphipleura rutilans
I hear from you

Greetings from the Netherlands
Jan Kros

[BJ]

Hello Franz e Jan,

I do not think that it can be Amphipleura as (?all) the species in this genus have an H-shaped chloroplast, with the chloroplast lobes running along either side of the cell. Your specimen has a number of small chloroplasts across the cell. I would vote for Nitzschia martiana...but if it is this species, I think it would be a first record for Europe! It is recorded from warmer waters.

Compare it with:

http://university.uog.edu/botany/474/di ... -mart.html

..this is a great site for marine tube-dwelling diatoms...perhaps you could email the author for his opinion of your specimen.

Ciao
Brian

[BJ]

Whilst the webpage I gave is correct, I realise that the website on tube-dwelling diatoms has been reconfigured and that some of the links do not work.

http://university.uog.edu/botany/Mar_Bo ... ellers.htm

will get you to the main page.

boa sorte

Brian

[Jan Kros]

Hello Brian,
Thank you for your explonation, i agree with Nitzschia martiana.
Also thanks foor this link.

Greetings
Jan

[Franz Neidl]

Hallo Jan and Brian!

Thank you very much for your help.
Yesterday I measured the alga carefully. It is 314 µm long and 6 µm wide.
I add two additional pictures. The first is showing the pseudothalli of the alga (in seawater in a Petri dish). The second the alga itself.

Franz

[BJ]

Franz,

Two more excellent photos - thank you. To my eye, the colony looks just like the one on Lobban's website. I think this is an interesting find and it would be good to get a confirmed identification from a professional. Apart from Lobban, I have just remembered another person with a special interest and expertise in tube-dwelling diatoms, Dr Eileen Cox in the Natural History Museum in London.

http://www.nhm.ac.uk/research-curation/ ... index.html

- perhaps it would be worth emailing her asking her to look at your photos here?

Ciao
Brian

[clobban]

This is Nitzschia martiana. It's a warm-water species.
You can see more photos of it on my diatom sites, http://test.protistcentral.org/Taxa/get/taxa_id/585369 and about tube-dwelling diatoms in general at http://university.uog.edu/botany/Mar_Bo ... ellers.htm