56
b I ( ’ T O l 1 I , t . O O ? A N O V b ’ A h l ) IIAllllY ( $ . l > A b l \
cnclosrirc~ at t l w (li-sitv(I h.vc.1, 1 hi, 1rrt)or;rtor.y ix rlow sirpplicd with
rich, mixcd I)~‘~tnpliLtlkt,ot~ ~ I I
i L ycw-routi(i basis.
A common difficulty expt~icwwcl in growing phytoplartkton it1
open tanks of sevcral-thousarttl-1itc.i. ciipscity, as is donc st Milford, is
invasion of these cultures by zooplankton organisms. In our mass
cultures the most common offenders are crustaceans, especially copepods. These forms multiply so rapidly in rich phytoplankton that they
soon consume most of the plant cells, rendering the culture useless.
FIG. 21. Mass culture of mixed phytoplankton grown in large nooden tank of about
2 000-gal capacity under s~rni-outdoor conditions. Desrription in text.
In the past, several methods were tried to prevent such contamination of open-air algal cultures, but they usually were unsuccessful
because some crustacean eggs were always left behind and eventually
hatched, reinfesting the cultures. Iiecently, we devclol)cd an extremely
simple and safe method to control t h s v infestations tJy mc.rc:ly adding
to our culturc~s, whtw ~lccc~ssa~ty, slrliill cjuantiti~s of’ insecticides
(Loosanoff et al., 1957). Several of thc:sc. substarlocs l ~ s v c t)eeri tried
and found successful in conccntratiolls as low as 0.1 ppm. A t present,
we use a commcrcial preparation known as ‘l’li!Pl’, which coritairiH 40%
of tetraethyl pyrophosphatc. ‘I’hc. advantages of uxirig 7’EI’f’ are
b I ( ’ T O l 1 I , t . O O ? A N O V b ’ A h l ) IIAllllY ( $ . l > A b l \
cnclosrirc~ at t l w (li-sitv(I h.vc.1, 1 hi, 1rrt)or;rtor.y ix rlow sirpplicd with
rich, mixcd I)~‘~tnpliLtlkt,ot~ ~ I I
i L ycw-routi(i basis.
A common difficulty expt~icwwcl in growing phytoplartkton it1
open tanks of sevcral-thousarttl-1itc.i. ciipscity, as is donc st Milford, is
invasion of these cultures by zooplankton organisms. In our mass
cultures the most common offenders are crustaceans, especially copepods. These forms multiply so rapidly in rich phytoplankton that they
soon consume most of the plant cells, rendering the culture useless.
FIG. 21. Mass culture of mixed phytoplankton grown in large nooden tank of about
2 000-gal capacity under s~rni-outdoor conditions. Desrription in text.
In the past, several methods were tried to prevent such contamination of open-air algal cultures, but they usually were unsuccessful
because some crustacean eggs were always left behind and eventually
hatched, reinfesting the cultures. Iiecently, we devclol)cd an extremely
simple and safe method to control t h s v infestations tJy mc.rc:ly adding
to our culturc~s, whtw ~lccc~ssa~ty, slrliill cjuantiti~s of’ insecticides
(Loosanoff et al., 1957). Several of thc:sc. substarlocs l ~ s v c t)eeri tried
and found successful in conccntratiolls as low as 0.1 ppm. A t present,
we use a commcrcial preparation known as ‘l’li!Pl’, which coritairiH 40%
of tetraethyl pyrophosphatc. ‘I’hc. advantages of uxirig 7’EI’f’ are