Phytoplankton Bleaching? / Colour Change?

[Zaita]

Hey guys,

I am culturing 4 types of Phytoplankton. Nannochloropsis oculata, Chaetocerous gracilis, Isochrysis galbana and Tetraselmis sp.

It has been going ok, I am feeding an F/2 silicate-free mix and adding Silicate to the Chaetocerous. But lately my Nano and Tet cultures have gone a yellowish-green?

This is my procedure.
- Cook glass flasks in oven @ 120'C for 1hr.
- Prepare ASW using RODI water and Salt Mix (1.022-1.027)
- Bring ASW to boil and boil for 5 minutes.
- Let ASW and Flasks Cool. (Overnight)
- Sterilise tools with mild bleach (Detol)
- Split Cultures.

Can anyone identify if something is wrong here? I was told it maybe chlorine so I add a tap water conditioner but that stopped the phyto growth almost completely!

Is there something wrong with boiling the ASW? Does this cause some sort of chemical reaction that makes the water unsuitable for Phyto?

Any help is much appreciated!

[billsreef]

Boiling the water could cause some things to precipitate out. But if that was an issue, your other cultures would be affected as well. How long are cultures going before they turn yellowish?

[Zaita]

Straight away after a split.

Instead of going back to the lime-green my Nano goes straight to a yellow-ish colour. So it has to be something to do with how I am splitting it.

[billsreef]

Are you adding the f/2 before or after you boil the water? Do you rinse those bleach sterilized items well before use?

[Zaita]

Originally posted by billsreef
Are you adding the f/2 before or after you boil the water? Do you rinse those bleach sterilized items well before use?

F/2 Is added after water has been cooled.

No I am not rinsing the bleach off well. Perhaps I should? Or refrain from bleaching?

It's a PITA because each culture costs me $75 and I have to wait 2-3 weeks for it to be innoculated from a research facility before it is delivered to me :P

[Zaita]

Ok.

Would this cause my colour change...

When I originally got given my cultures I was given 2 different types of food.

1) A single F/2 Mix I should use at 1ml/L.
2) A 2-Part Mix containing (A) Vitamins and Trace Metals and (B) Nitrate and Phosphates

So I was using No.1 For a while and then needed new food so got more of it. Somewhere I think I started using No.2-(A) by itself instead (same colour and similar labelling).

Err I know dumb! But would this have caused my problem??? I have corrected this today and am trying it on backup cultures.

Thanks guys!
Scott.

[billsreef]

Using the 2 A by itself would indeed cause such problems It's the B (nitrate and phosphate) that are the main ingredient to get the phyto growing. I'll bet now your cultures grow nice and green

BTW be sure and rinse that bleach off well, a little bit can be a real problem. For tools, I use a no rinse sanitizer that I use for brewing. Iodophore, it's iodine based so not a problem if a few drips remain behind. It can be found in any home brew supply store or farm supply or restaurant supply store as it's also used in dairy's and restaurants.

[Zaita]

Thanks guys

My new F/2 is in the country and arrives tomorrow! Seems like the F/2 I was given recently had some issues as the other guy who has phyto (only 2 of us in NZL :P) had similar issues when using it.

Seems like they are getting back on track now.

[billsreef]