Question

im growing algae Chlamydomonas and after 12 hours light cycle it's oxygen concentration is only 0.05 mg/L, when Chlorella oxygen concentration after light cycle is 14 mg/L. And im interested why here is such difference? (:

Answer 1

Honestly, I don't know, but I've got a few thoughts on the matter. First of all, if you've only tested after a single 12 hour period, it COULD just be random variation.

There are differences in the efficiency of photosynthesis between different species, as far as I know... but another possibility is that you've simply got more Chlorella than Chlamydomonas in your samples, or that the Chlorella are healthier/happier for some reason.

Answer 2

i grow Chlamydomonas on TAP medium and on water with small amount NH4Cl, and Chlorella on Bangladesh No.3 medium with glycerol and glucosis small amounts. And only Chlamydomonas after 3 days started rapidly reduce oxygen.

Answer 3

and it eas testing not only single 12 hour period, it was testing 14 days at same time after about 20 minutes when light had been turned off.

Answer 4

and how often did you record the oxygen concentrations?

Answer 5

and its not possible that i have more chlorella than chlamydomonas, because i also chek optical density and chlamydomonas there was much more than chlorella.
about flagella i always mixed the medium before measurement.
and about amoniumchloride, the same situation with oxygen was and in flask with fresh water, so its only chlamydomonas fault, but i would like to know why (:

Answer 6

i record oxygen concentration every day at the same time during 14 growing period after about 20 minutes when light period end (:

Answer 7

but its fact that the main reason of low oxygen is chlamydomonas but not a medium or something else

Answer 8

what else do you keep track besides the oxygen concentration? temperature, etc.
I want to rule out the ammonium chloride if possible.

Answer 9

and rule out that there are no other specimen(s) in the TAP besides chlamydomonas only

Answer 10

temperature, ph,electrical conductivity and optical density. there was the flask without amonium chloride only water, but results were the same.
and temperature and etc. measuremens were quite similar like in chlorella

Answer 11

what was the initial read of O2 concentration?

Answer 12

i dont have ability to measure it

Answer 13

@Calliope
what do think?

Answer 14

oh, sorry, i read co2, the initial read of o2 was in TAP 4.8 and in water 5.2 and on 2nd day in TAP it was 0.2 and in water it started drop only on 10th day

Answer 15

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
4.84 0.39 0.13 0.09 0.07 0.04 0.06 0.03 0.04 0.03 0.09 0.07 0.3 0.08 0.19

Here is TAP medium days and o2 concentration

Answer 16

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
5.21 9.83 9.68 4.08 5.7 10.024.142.39 2.26 2. 70.15 0.09 0.23 0.11 0.16

and here is water

Answer 17

when chlamydomonas perform anaerobically, what happens to the O2 concentration of its environment?

Answer 18

and is it possible that the type of chlamydomonas being used are unable to perform photosynthesis?

Answer 19

but cells are green, so the should have chlorophyl and should process photosynthesis, i think.

Answer 20

chlamydomonas can adopt anaerobic metabolism and has the ability to grow heterotrophically.

Answer 21

yes, i know that, but if it became heterotroph dont he change its colour?

Answer 22

I don't know enough if that is necessarily so. But that's highly probable.

Answer 23

i found that in one article
"Chlamydomonas belongs to the group of eukaryotes bearing primary plastids, called Archaeplastida in newer schemes (Adl et al. 2005). It provides an example of a generalist facultative anaerobe among eukaryotes. When grown aerobically, C. reinhardtii, a typical soil inhabitant, respires oxygen with a normal manifestation of oxidative decarboxylation via pyruvate dehydrogenase and oxidative phosphorylation in mitochondria (Cardol et al. 2005). But when grown anaerobically, it rapidly expresses PFO, PFL, [Fe]-Hyd, ADHE, acetate kinase and phosphotransacetylase and produces acetate, formate, ethanol and hydrogen as major end products (Mus et al. 2007). Chlamydomonas thus expresses many of the enzymes mentioned above that were once thought to be specific to anaerobic eukaryotes lacking typical mitochondria."
and i think it could be something similar to this

Answer 24

by the way, thanks a lot! i think you showed me the right way!

Answer 25

k. no problem