rotifer resting egg hatching 100X objective (Brachionus)
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jc maccagno
- Posts: 509
- Joined: Tue Dec 21, 2010 5:43 pm
rotifer resting egg hatching 100X objective (Brachionus)
Buse Lake is a shallow(3-6 metres) alkaline pond..pH 12. Every 10 years or so it becomes totally oxygen depleted. The water becomes port wine colored and the area has a very strong smell of H2S. Samples were taken from bottom silt and the upper 12 inches of water. The silt sample was well populated with resting phase rotifer eggs. Samples with eggs were placed in freshwater and observed for 1 week..2 were photographed in the hatching phase
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jc maccagno
- Posts: 509
- Joined: Tue Dec 21, 2010 5:43 pm
rotifer egg hatch
Hello Mitch,
In response to your questions: The eggs have been described as "resting eggs" They are very resistant to adverse conditions and they can survive for long periods of time in that state.
I divided a 100cc sample of water/bottom silt into 2 50cc samples. I simply sealed one and left it. The other half was diluted with 30cc of tap water( to mimic the spring runoff) and sealed. Both samples were kept in the same conditions: 20 degrees C and in indirect sunlight.
The samples were scanned every day for signs of change in the eggs and for other organisms.After each session the material on the slide and cover slip was flushed back into its specific sample jar using fluid from the appropriate sample jar. As a rule each scanned slide had from 1 3 eggs.
There was no change in the appearance until about 1 week later The first change was a deepening of color and a mottled appearance. This was seen only in the water diluted sample.From then on I prepared vaseline coated slides and continued my daily scans. These samples did not dry out for hours.
About day 9-10 I hit the "jackpot" an egg with movement within. I focused on this specimen with a 100X objective and watched if for about 4 hours. I finally left it for the night and returned to it in the morning. The egg was no longer in the field. I switched to a lower power and found 1 swimming Brachionus sp. The other egg in the sample was unchanged. I did not see the hatch itself. I had the good fortune of capturing the similar event once more in the ensuing weeks. Again it seems to take many hours and I did not witness the hatch but same result.
The water was tested by a biologist. pH if 12 confirmed and "zero" O2 in entire water column.
Hope this answers your questions.
All the best
john
In response to your questions: The eggs have been described as "resting eggs" They are very resistant to adverse conditions and they can survive for long periods of time in that state.
I divided a 100cc sample of water/bottom silt into 2 50cc samples. I simply sealed one and left it. The other half was diluted with 30cc of tap water( to mimic the spring runoff) and sealed. Both samples were kept in the same conditions: 20 degrees C and in indirect sunlight.
The samples were scanned every day for signs of change in the eggs and for other organisms.After each session the material on the slide and cover slip was flushed back into its specific sample jar using fluid from the appropriate sample jar. As a rule each scanned slide had from 1 3 eggs.
There was no change in the appearance until about 1 week later The first change was a deepening of color and a mottled appearance. This was seen only in the water diluted sample.From then on I prepared vaseline coated slides and continued my daily scans. These samples did not dry out for hours.
About day 9-10 I hit the "jackpot" an egg with movement within. I focused on this specimen with a 100X objective and watched if for about 4 hours. I finally left it for the night and returned to it in the morning. The egg was no longer in the field. I switched to a lower power and found 1 swimming Brachionus sp. The other egg in the sample was unchanged. I did not see the hatch itself. I had the good fortune of capturing the similar event once more in the ensuing weeks. Again it seems to take many hours and I did not witness the hatch but same result.
The water was tested by a biologist. pH if 12 confirmed and "zero" O2 in entire water column.
Hope this answers your questions.
All the best
john
