We are trying to produce in the laboratory gametophites and sporophites of Laminaria digitata and Saccharina latissima together with Palmaria palmata. Still we are struggling to get rid of the diatoms present in our fertile material. Even pre-treatments with iodine or bleach, as well as manual scrubbing and several washes with filtered and autoclaved seawater do not help to solve the problem. Thanks to everyone that can give a hand for this!
Try growing your seaweed in artificial sea water made without silicate. This should solve the problem.
Hi, I used to sample phytoplankton and when we wanted to get rid of Diatoms in raw cultures to study specific classes, we used germanium oxyde (GeO2) which blocks frustule synthesis and then kills diatoms. I only hope this is not toxic to kelp. Good luck.
Hi,
Some reserchers use distilled water. Other non chemical method is to brush with rubber "shovel" use to spread chocolate or else.
See this paper
http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0188-88972008000200002
Hi,
You could use Germanium Dioxide - this method is sometimes used for getting rid of unwanted diatoms, if you intend to isolate algal clones. Germanium is replacing Silica and will be lethal to them. Please see eg. Andersen R.A.2005(ed). Algal culturing techniques page 98 or Lewin J. (1966) Silicon metabolism ion diatoms v. germanium dioxide, a specific inhibitor of diatom growth. Phycologia 6:1-12.
Good luck and kind regards from Vienna
Michael
Either Oscar's or Fabien's suggestions should work. In either case treatments might cause some damage to your kelp specimens, but even if still present in low numbers, diatoms should delay growth for some days, so that if necessary, algae will have time to recover. Treatments may be then repeated until your algae become diatom-free. Good luck
In our lab we pre washed the algae with fresh water for a few minutes. it helps to remove epiphytes
Inmmersion in sea water with 1ml per liter of sodium hypochlorite for 1 minute and rinse with seawater gives good results
Hi.
Just try to add germanium dioxyde (GeO2). It is a very powerful and selective poison against diatoms and it will not affect organisms without silica metabolism:
http://ac.els-cdn.com/073497509090647T/1-s2.0-073497509090647T-main.pdf?_tid=b1910f4c-8335-11e3-97eb-00000aab0f26&acdnat=1390375418_8da20f271bd749315a320b10333efd7e
All the best,
Ignacio Moreno-Garrido
I think this paper can come in handy to you since the GeO2 method is used in one ouf your kelp species:
Shea, R, Chopin, T. 2007. Effects of germanium dioxide, an inhibitor of diatom growth, on the microscopic laboratory cultivation stage of the kelp, Laminaria saccharina. Journal of Applied Phycology. 19(1): 27-32.
Regards,
Raquel Sánchez
Article Effects of germanium dioxide, an inhibitor of diatom growth,...
Dear Maria,
I do not if I undestandle very well you question, but I can offer you two points: Number one: Algal blooms, nuisance species, and poor water quality may be nearly as, or more, troublesome than macrophytes. This chapter describes immediate and sometimes short-term techniques for coping with these three common concerns. From: http://www.dec.ny.gov/docs/water_pdf/dietlakech7.pdf
Diatom frustules dissolve at high pH, e.g. in Sodium carbonate or Sodium hydroxide (at pH=10). We use it to get rid of diatoms (and radiolaria) from sediment samples prior to grain size analysis. To what extent this harms the kelp for your analysis, I don't know without further information
Hi Maria the second one is: A new method for the quantitative separation of diatom
frustules from lake sediments, from: http://aslo.org/lomethods/free/2004/0025.pdf
Sincerely,
Márcia Eler
Over the years, the topic has been discussed several times on the web.
You may find useful suggestions at the following link:
https://listserv.heanet.ie/cgi-bin/wa?A2=algae-l;CJXtXQ;20110212221103%2B0000
In this archive, also the pdf on a paper discussing epiphyte removal methodologies (Zimba & Hopson 1997, Quantification of epiphyte removal efficiency from
submersed aquatic plants) is available.
Good luck & Best regards
Marco
One method is to use artificial sea water,wherein there is no trace of silica,in absence of which the diatom doesn't have the possibility to grow .
Dear Maria Scolamacchia,
Hello
1 have a question?
how can diatoms be treated in natural lake? in order to treat eutrophycation?
regards,
@ Elham,
In most cases,eutrophication is due to good amounts of availability of P, & to remove this out, use Lemna & Spirodela which will use this element up.See that both these macrophytes are physically removed out from the lake, so that P doesn't get back into the system.Once the N:P ratio comes to natural level,eutrophication due to diatoms will cease to be a problem.
Recently we killed diatoms in our Nannochloropsis culture by adding 10 mM GeO2 to growth F/2 medium. Works fine!
you may try a freshwater bath (10-15 min) . See:
http://www.scielo.org.mx/pdf/hbio/v18n2/v18n2a2.pdf
if it does not work, try the GeO2 option, but be aware that you will have to repeat any treatment as needed, since none is really long lasting.
good luck
@ Garry Benico It is not dissolving in water, does it work while it looks even cloudy?
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