Phytoplankton Taxonomy - Science topic

This is almost certainly Cocconeis, though I specialize in freshwater taxa, so I suppose it could be an obscure, similar, marine genus I'm unaware of. That being said, it is not Diplomenora cocconeiformis. You are correct that the presence of a raphe excludes that genus. See-

Dear Anton,

The genus Hyalosira was amended and lectotyped by Lobban et al. (2021); Diatom Genus Hyalosira (Rhabdonematales emend.) and resolution of its polyphyly in Grammatophoraceae and Rhabdonemataceae with a new Genus, Placosira, and five new Hyalosira species, Protist 172, 25816.

H. obtusangula, which is one of the species together with H. delicatula described by Kützing (1844), was chosen as the lectotype of Hyalosira.

The specimens that you are showing in the pictures clearly do not match Hyalosira emend Lobban, Ashworth and Majewska in terms of girdle band morphology: copulae bearing two rows of areolae separated by a midrib.

Even when certain characters are not in view, the bands bring the displayed material closer to Placosira as mentioned by Roksana in her answer.

All the best.

Eugenia

Mar Fernández-Méndez

Hi Mar,

The core part of CHEMTAX is basically to solve an overdetermined linear inverse problem. If you are an R player, the package `limSolve` by Karline Soetaert et al. provides an example of how you can do it. Try `help(limSolve::Chemtax)` in your console once you install it. Or find it in this link: https://search.r-project.org/CRAN/refmans/limSolve/html/Chemtax.html

Hope this helps. Good luck and regards,

Shun

Paint with Calcofluor and look at the plate under epifluorescent

All best...

Those looks like coccolithophores, probably shed their calcite discs..

All best

Dear Kim,

I am sorry, but identification with these photographs are not possible. I do not thik this is Mougeotia, which belong to the Zygnematophyceae. The Form of cells look unusual with redard to cell lenght and with and even with fixed material you normally will be able to regcognize the plate-like shape of the chloroplast and the pyrenoids on it. Please find a typical picture below.

All the best

Antje

Dear Aysha:

Fig. 1 belongs to the genus Halamphora, but it is not H. tenerrima, see pictures of the type material in Clavero et al. (2010), Diatom Research 15 (2): 195-208.

Fig. 2 belongs probably to the genus Lyrella

Figs 3 and 4 could belong to the genus Pinnunavis

Fig 5 belongs to the genus Pleurosigma

The last picture is not good.

Kind regards.

Eugenia

Dear Rinaldi:

Your last picture probably is a species of Amphora or Halamphora.

I do not agree in determining your first picture as Climacosphenia because there is not evidence of the characteristic septa. Compare with the picture from Algaebase and see pictures in Round et al. (1990).

You need to analyze the generic features in detail for determining genera. 

Regards.

Eugenia                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               

Dear Mike,

I am working in this field on fresh waters and I would recommend:

Bukata, Robert P., et al. Optical properties and remote sensing of inland and coastal waters. CRC press, 1995;

Lee, Robert Edward. Phycology. Cambridge University Press, 2008;

Bellinger, Edward G., and David C. Sigee. Freshwater algae: identification and use as bioindicators. John Wiley & Sons, 2015;

Reynolds, Colin S. The ecology of phytoplankton. Cambridge University Press, 2006;

If you are working with satellite remote sensing data I would recommend spending some time reading the IOCCG report number 15, 2014 (attached)

regards,

Isabel

If your sample is the fresh water, maybe your first pic is A species from Crucigenia sp.

Rene:

It could possibly be a variant of D. caudata but does not match D. acuminata. Kindly compare in this link:

Hi Aysha. This is definitely Actinocyclus. As well as the very distinct marginal opening (pseudonodulus) and hyaline rays which characterise this genus, it has many rimoportulae (labiate processes) around the edge of the valve, very clear in the internal SEM photo (third one down), and strongly resembles A. octonarius, probably var tenellus. The attached publication may be useful (see figs 1-14). Best wishes, Alex 

Great! Thank you very much.

Do yo know if this species form colonies instead chains?

Dear Jennifer,

this is absolutely sure Ciliophora. You are using not wright format for the photos. Better to use jpg. Sp, No 3 cannot download.How did you make this photos? This is the same cell or different? For me two different species. No 4 looks like Genus Cyclidium (may be glaucoma group). Oral membrane is enough transparent so should use phase contrast. If the specimens jumping, so not hesitation. Period between jumping is feeding! But jumping is not the only one important char. as Halteria or Urotricha can do, like a lot of others. Should inhibit by special liquid for precise investigation. Look my paper from 1979 with Boshko.

First two photos look like Cyclidium as well, but other species with small membrane (related view have some repr. of Uronema & Dexiotricha but diff oral structure). serious identification is possible only by silver (dry or wet) or protargor impregnation.

Andrey

Hello Malcolm, hello Salah

i have just learned from my colleagues in the laboratory that they have already used the sampling equipment in marine water, and there is no connection between lake and sea. I apologize for the inconvenience.

Best regards

ARAB S

Phaeocystis?

Dear Melati,

    Surely you have to look at the striae using higher resolution. It could be a Gyrosigma, however ...

    Take care,

    Carlos

Dear Gustavo,

Agree with Prof. Eugenia that  it is not Eudorina or any other member of Volvocales.

On the basis of the picture provided, I suggest it as species of the green alga Coenocystis most probably C. micrococca J.Komárek

Please refer: Komarek J. 1983. Contribution to the chlorococcal algae of

Cuba. Nova Hedwigia 37: 65-180

Good luck!

Thank you, everyone. I also identified them as Nephrocytium. The gelatinous sheaths were not clear for in these samples.

Dear Anila,

The above suggestions could be good, but I also agree that determination on the species level based on one image can be difficult. As for the names, I suggest that you check the currently accepted ones in AlgaeBase (http://www.algaebase.org/).

Much literature I've seen often focuses on the stria or areola density near the valve margin. For which you can measure the stria in two different ways, chord count vs. the circumference count. The chord count is similar to your lines, where you measure the ornamentation within a 10 micron scale bar. The circumference count you would count all the way around the valve and calculate the stria density based on the circumference. Either way are good, the chord count is the traditionally used method, but it is best to note which method to use. 

Sorry to digress, but of your question I would count your red line, because then you are discussing the the areola density for a stria. It would be a consistent unit of ornamentation to measure within. I think ultimately it is important to note which method you use and try the best to understand the methods used by the authors of your taxonomic resource.

It is an area of uncertainty and probably not yet harmonized because the methods of quantifying ornamentation vary with the diversity in ornamentation.

looks in first instance like a scale from a butterfly or a moth.

Best wishes, René

It's much too small to be part of a flower. Maybe it's a spicule. Is this the only one you found?

This genus seems Pseudo-nitzschia. 

Dear Eyasu. Species identification using an key is complicated. Tipically, more powerful tools for ultrastructure determination are necesary. A good strategy: Identify to genera level and later use phycological specie level description from research articles.

Regards. 

Looks like Stauromedusa for me

This is Heliocotheca (= Streptotheca) tamensis (SHRUBSOLE) RICARD (centric diatoms).

Best regards

Lothar Täuscher

Dr. rer. nat. Lothar Täuscher

- Diplombiologe -

Petersburger Str. 44

D-10249 Berlin

Dear Anila,

I agree with Dr.Kevin regarding the number of striae and its significance in the  identification of diatoms. My suggestion on your photomicrograph is  that  it could be a species of Pinnularia.

Best regards

Dear Navnith,

Your micro-photo is of a very poor quality. Nevertheless,  it can not be Asterionella by any means due to the central structure of pentagon (sometimes observed) and elongated spikes, which may sometimes be found in silicoflagellates - Dictyochophyceae. Moreover, Asterionella is a diatom freshwater planktonic genus while silicoflagelaltes are typically marine plankton species. I am attaching two related photos just for comparison, since my filed is not the marine but freshwater environment. 

Best wishes for your work. 

There are countless algae species of similar appearance. Moreover, the appearance can change depending on growth conditions, cell densities and other factors. In addition, there is no size information. To obtain morphological details you would need a much higher resolution (electron microscopy). Getting physiological or ecological data would be helpful but it is a laborious thing. Nowadays, the best way to unambiguously identify an algae species is DNA barcoding (using for example ITS-2 regions). 

By the way, the algae on your photos are definitely not Volvox or Euglena species…

These look like flowcam photos. They are mucilaginous amorphous aggregates of detritus containing fine clay particles,  what appear to be some algae but also pollen grains and starch grain from higher plants  but they are not clear and to properly ID you need to use higher power magnification.

Karnan,

It is a diplopsaloid type dino.  To get to the genus/species (Diplopsalis, Diplopsolapsis, etc) you need to examine the thecal plates on the bottom half of the cell.

It is most likely a zoospore.  When Haematococcus is nutrient deplete or limited it can enter a sexual stage, where the zoospore will appear like small Chlamydomonas cells.

Dear all:

In my opinion it is not possible to determine the genus of the material presented by Karnan based on the photographs presented by Karnan.

Karnan I recommend get Sundström’s doctoral thesis, Sundström (1986). The marine diatom genus Rhizosolenia. Lund University code LUNDBS / (NBBS-1008) / 1-196.

This author split Rhizosolenia  s. l. in several marine genera: Rhizosolenia s. str., Proboscia Sundström, Pseudosolenia Sundström as was pointed out in previous comments. The differential features between genera would not be visible in these pictures.

I also recommend you the paper about Rhizosolenia s. st., Neocalyptrella, Pseudosolenia, Proboscia by Sunesen & Sar (2007) in which you can see the necessary features for determining an Rhizosolenia s. str. as R. setigera.

Kind regards.

Eugenia

It's more close to A. druartii than to A. microcephalum or A. gracillimum, IMHO

Use a clone library approach by using both 16/18S and functional gene primers. This is a low cost but tedious method. Or else if you have funds then u can go for deep sequencing approach.

I suggest you to contact Gill Mapstone (NHM in London), at g.mapstone@nhm.ac.uk, as your animal resembles an early stage or a part of of a physonect siphonophore (Hydrozoa). I attach herein her last review on the global diversity of this group. In your pic I see six tentacles in two orders, and the rounded structures below them may look like small nectophores. 

Theoretically you could have a unbounded growth as long as the species doesn't reaches the K limit right. Well in planktonic life the g value or Generation time is quite sharp and its life time is what you define or bound the K limit for the species. Naturally, the documented literature varies reasonably well in the context of E.huxleyi. 

Figure is not much clear to identify, provide the clear picture to identify it properly

I also agree, this may be a representative of Oscillatoria also common in Sri Lanka in small numbers, Contact Prof. Eugen Rott for further details.