ARTEMIA PARTHENOGENETICA from SALINA DI CERVIA or why are some Artemia red ?
Those are two close up images for Artemia Parthenogenetica, which is a female-only
strain of Artemia. I got these specimens from the Salina di Cervia near Ravenna in northern
Italy.
BTW: I brought 4.5 grams of Artemia Parthenogenetica eggs from Cervia, which is a volume
of about 13 cm3.
13-SEP-2006:
Next scientific task:
Determine the reason for the red color of these specimens.
Since they are red in the Saline of Cervia, and 3 weeks after feeding with green algae
instead of Dunaliella, which is a red algae in the Salina di Cervia, they are still
red, I guess Dunaliella can be ruled out. Low oxygen content may be a reason, but
on the other hand I never recognized any red coloring with Artemia salina.
I think that the red color is typical for Artemia Parthenogenetica. I will prove this
with eggs I brought from Cervia - I will grow some of those eggs in a new tank soon,
feeding is only with green algae and we will see if those Artemia Parthenogenetica
will be red too. If they are, the red color is typical for Artemia Parthenogenetica,
if not, either oxygen level or the feeding with Dunaliella is resposible for the
red color.
24-NOV-2006:
It's seems I was completely wrong with the above assumptions.
First, the Artemia parthenogenetica from Cervia in the normal tank with a salinity
of about 32g salt per liter, almost lost their red color and they are almost pale now.
So Dunaliella might again be the reason for the red color, because there are no
Dunaliella in this tank and therefore they became pale. The Artemia parthenogenetica from Cervia in the original
water from Cervia still are very red. This might be due growing Dunaliella in the tank or raised
haemoglobin levels due the high salt content and therefore low capability of the water
to hold dissolved oxygen.
Second, the Artemia parthenogenetica grown from eggs, feeded only with green algae, in
a tank with a salinity of about 32gramms per liter water,
are very pale, but with a slight red coloring on some adults. The reason for the
slight red color is still unknown, but read below for explanations.
Third, and now there's the evidence that the RED Dunaliella is actually responsible
for the color of the Artemia and also for the pink/redish color of the Flamingoes if they eat
the red Artemia:
Sánchez, Georgiev, Nikolov, Vasileva, Green (2006) cite Amat, Gozalbo, Navarro, Hontoria, Varó (1991)
Some aspects of Artemia biology affected by cestode parasitism
in their paper: Red and transparent brine shrimps (Artemia
parthenogenetica): a comparative study
of their cestode infections:
The red colour of brine shrimps is believed to be a result
of accumulation of carotenoids (Amat et al. 1991)
Dunaliella contain lots of carotinoids (hence the red color).
The pigments of Artemia Gilchrist, Green (1959, 1960 ?)
The red or orange colours of adults may also be due
to carotenoids (Lochhead & Lochhead 1941), but another
frequent cause of redness in adult brine shrimps
is the presence of haemoglobin.
[...] the concentration of haemoglobin in the blood
of Artemia varies inversely as the oxygen content of the
water [...] In natural populations an increase in redness
of the animals with increase in salt content of the
environment has been noted several times (Payen 1836; Joly
1840; Schmankewitch 1877; Kellogg 1906; Artom 1905)
Some other notes: Aharon Oren: A hundred years of Dunaliella research 1905-2005:
[...] massiv accumulations of beta-carotene [...] under suitable conditions.
[...] first discription [...] 1838 by Dunal.
[...] most of the coloration of the crystallizer brine is caused not by the algae but by
red halophilic Archaea (Archaebacteria) instead.
[...] reproduce by longitudinal division of the motile cell or by fusion of two
motile cells to form a zygote.
Dunaliella salina and Duneliella viridis: Dunaliella salina has somewhat larger cells,
and under suitable conditions it synthesizes massive amounts of carotenoid pigments, coloring
the cells brightly red. D. viridis never produces such red cells.
The pigments responsible for the brightly red coloration displayed by Dunaliella salina,
often designated in the older literature as "hematochrome", was recognized already
very early as a carotenoid. [red caroteniod pigment]
[...] beta-carotene, the major carotenoid accumulated by Dunaliella salina [...]
[...] 13.8% of the total dry organic matter in the D. salina [...] was estimated to be
beta-carotene.
Amat et al.: Some aspects of Artemia biology affected by cestode parasitism:
[...] parasites can provoke severe changes [...] Bright red color displayed by parasitized
Artemia is an example of this mechanism.
Sánchez, Georgiev, Nikolov, Vasileva, Green (2006): Red and transparent brine
shrimps (Artemia pathenogenetica): a comparative study of their cestode infections:
Although the red color of the brine shrimps has previously been supposed to be
associated with cestode parasitism, no evidence has been provided that red and transparent
brine shrimp differ in their role for cestode circulation.
Carotenoids are believed to be the main pigments responsible for the red colouration
(Amat et al. 1991). Thiery et al. (1990) reported that up to 22.8% of individuals in Artemia
populations infected with cysticercoids of the hymenolepidid cestode Flamingolepis
liguloides were red. Robert and Gabrion (1991) suggested that the occurrence of cysticercoids
of this species in brine shrimps was accompanied by red colouration but did not
provide any comparative data on the infection levels in red and transparent individuals. Amat et
al. (1991) found higher total lipid levels in infected brine shrimps and believed that
they were linked to the increased concentrations of carotenoid pigments conveying the red
color of parasitised shrimps. However, none of these studies have provided evidence that
the red pigmentation of brine shrimps is associated with the presence of cysticercoids.
The red color of the brine shrimps is believed to be a result of accumulation of carotenoids.
(Amat at al. 1991). Artemia individuals contain high concentrations of carotenoids,
particulary under hypersaline conditions, where algae provide the major food source
(Abatzopoulos et al. 2002).
One possible explanation is associated with the hypothesis that metacestodes modify
brine shrimp colour to favour transmission to avian predators that act as final
hosts (Robert and Gabrion 1991). Making the upstream host more visible to the predator
is recognised as one of the major mechanisms facilitating parasite transmission along
food chains (see Combes 2001; Moore 2002).
Increased carotenoids and lipid reserves in infected Artemia (Amat et al. 1991) may also
function as a parasite strategy to increase the longevity of infected individuals and,
thus, to enhance the probability of transmission. In the host-parasite system studied
by us, an indirect effect (Thomas et al. 2005) of the cestodes on the color of the
intermediate host seems likely. [...] However, we found that 13% of the red brine shrimp
were uninfected, and therfore, cestodes cannot be the only cause for their pigmentation.
UPDATE 03-FEB-2007: SUCCESS!!!
Despite all efforts to reproduce red coloring in Artemia with high salinity or feeding with
Dunaliella carotenoids, I have not succeeded so far. But today I discovered that there is
actually one adult in the "low-surface-experiment" tank. This tank is basically a round tube with
a diameter of about 30mm and a height of about 200mm. The surface area is very low so
very little oxygen comes into the water. The tank was not aerated since I put the eggs in
about one month ago (salinity 32g/l). I only added one drop of liquid algae at the beginning
and didn't feed after that.
Many nauplii hatched, but due the low oxygen content only one reached
adulthood. Unfortunately there is so little water in the tank that I can't perform an
oxygen test, but I expect it to be less than 2mg/l.
Here is a photo of the adult with the red color:
Clearly visible are the 2 eyes and the remaining nauplius eye, the digestive ceca and
the gut. This photo was shot while the Artemia was close to the surface. The green
areas is algae powder and above the water line, there are some unhatched eggs on the
inner wall of the tank.
UPDATE 01-MAR-2007:
Meanwhile the adult with the bright red color died, but some
nauplii are appearing on a regular basis. Maybe one will make it to adulthood with that low
oxygen content, so we can reproduce the above finding.
