New look at bioluminescence data

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New look at bioluminescence data

• Line setup
• Data acquisition
• Optical background rates _at_ 2000 m
• Sea currents
• Correlations
• Biolum vs. current
• 2000 m vs. 3000 m

2
Experimental layout
3
Batteries
Functional diagram
Container
Scaler A
CPU
Mem
Scaler B
Discri A
Discri B
4
Acquisition principle
Timer, then CPU triggers the development of a
sequence
5
Counting algorithm
7.8 ms
Time limit?
Read Store
no
N0
End of run
Counter reading done in flight ? no dead time
Count duration integer number of ticks ? very
precise
Dead time between counts ? 1 tick

• What is computable
• Average frequency for each count

• What is not accessible
• The timestamp of the pulses
• The shape of the pulse

6
Acquisition principle
Timer, then CPU triggers the development of a
sequence
Everyday starts _at_ 0h and 12h
We got 419 files !
?Base lines
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Most of the time
But, sometimes
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Baseline extraction

• Full distribution to define cuts.
• Choice 45 lt FA lt 75 kHz

Biased due to tail on the right
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Baseline for the full sample
? 50 kHz
? 30 kHz
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• c2 gt 3
• rmsA gt .8

Reduced sample
? 217 runs left
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Burst fraction
Which definition?
Number of peaks ? threshold to be defined
Time fraction above threshold ? to be defined
Sources of continuous background

• K40 Poisson distribution
• Bacteria emitting continuously light Poisson
  distribution

? Points in the time stream will fluctuate
according to Poisson law
Lets take as limit mean 3 rms
For counter A ? 75 kHz
12
Current velocity
Measurements performed every 30 mn Single shot
measurement ( not average!)
Some peaks at 10 cm/s Average value
3.26 1.62 cm/s
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Current direction
Dominance NW and SW
Many turns
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r days
q heading
Units km
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Correlation Burst Rate / Current velocity
Clear relation between burst activity and current
velocity
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Correlation with depth Current directions

• 2 preferred directions

• 210
• 300

• Especially _at_ 3000 m

• Correlated ?

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Correlation with depth Current velocities
Comparison, first
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Conclusions
Background rates measured over 100 days at 2000
m depth at thresholds of .5 and 1 spe
2 times higher than a previous measurement done
_at_ 3000 m
Correlation of burst rate on current intensity
A lot of interesting current data. Need to be
interpreted by expert!!!!