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Re: Daphnia Culture
Hi Dan.
I think I see the difference between your methods and mine. I don't push
the culture to produce the sort of volumes you're producing, mainly because
I don't need them, so on a longer time period my system is much more
stable. I would bet that you're feeding your daphnia more frequently than I
do too (I feed them about twice a week). I maintain D. magna at about 22
degrees C. I generally give them about 14-16 hours of light per day. Under
these conditions I never have crashes, but having said this, as I'm not
trying them to produce the numbers you describe, I believe that the time
factor is greatly slowed. I'm curious to learn how often you feed your
cultures and at what temperature and photoperiod you maintain them. I'm
also interested in hearing about your water chemistry.
So in respect to volume, if one is really pushing one's Daphnia cultures to
produce the numbers Dan describes, I concede that frequent water changes
are necessary.
Regards,
-John
At 03:58 14/02/01 -0500, you wrote:
>Date: Tue, 13 Feb 2001 23:32:27 -0500
>From: "Dan McMonigle" <mcdaphnia at lycos_com>
>Subject: Re: Daphnia culture
>
> I have to respectfully disagree with John. Changing water daily or or more
> often is necessary to leveling out the pulse and crash tendencies of
Daphnia.
> When "pushing" the production of my Daphnia, I set time aside about every
> eight hours to check, feed, and change water as needed, three times as
often
> as the Dean of Daphnia. A more laidback method such as John's will likely
> work, in the sense that someone with their old TI computer that uses
cassette
> tapes for memory has a working computer. I brought about 100 bags of
Daphnia
> to an ALA convention a couple years ago. I think there was a tablespoon or
> two (drained) of Daphnia in each bag. I could not tell that I had taken
> anything out of my cultures. Maybe that would also be true of John's
> cultures. I don't know but I'd be curious. Always ready to learn new
things!
> Or gain new insight into the correctness of old ones!