AUTOMATED CONTINUOUS ZOOPLANKTON CULTURE SYSTEM

• US 20120312243A1
• Filed: 12/09/2011
• Published: 12/13/2012
• Est. Priority Date: 12/09/2010
• Status: Active Grant

• Current Assignee: Board of Supervisors of Louisiana State University Agricultural & Mechanical College (Louisiana State University System)
• Original Assignee: Board of Supervisors of Louisiana State University Agricultural & Mechanical College (Louisiana State University System)
• Inventors: Rusch, Kelly A.
• Granted Patent: US 8,973,531 B2
• Time in Patent Office: Days
• US Class Current: 119/204
• CPC Class Codes: A01K 29/005 Monitoring or measuring activity, e.g. detecting heat or mating
• CPC Class Codes: A01K 61/00 Culture of aquatic animals receptacles for live fish, e.g. aquaria, A01K63/00
• CPC Class Codes: A01K 61/20 of zooplankton, e.g. water fleas or Rotatoria
• CPC Class Codes: A01K 61/59 of crustaceans, e.g. lobsters or shrimps
• CPC Class Codes: A01K 63/06 Arrangements for heating or lighting in, or attached to, receptacles for live fish
• CPC Class Codes: Y02A 40/81 Aquaculture, e.g. of fish

Abstract

A system and method are disclosed for determining the concentration of zooplankton in a continuous zooplankton culture system. The system may include a transmissiometer, a sample tube, a first sample containing water and microalgae, and a second sample containing water, microalgae, and zooplankton. The concentration of zooplankton in the system may be calculated by comparing the transmissiometer output from the first sample and the second sample, wherein each of said outputs are obtained by moving each sample into the sample tube such that the transmissionmeter is positioned to take a reading across the tube.

Claims

1. A system for monitoring zooplankton concentration in a zooplankton culture system, comprising:

a light source;

a photodetector;

a pump;

a first sample;

a second sample;

a sample tube;

a digital storage device; and

a microprocessor,

wherein the light source and the photodetector are positioned on opposite sides of the sample tube such that the photodetector is positioned to detect the light emitted from the light source through the sample tube;

wherein the first sample comprises water and an unknown concentration of microalgae from the zooplankton culture system;

wherein the second sample comprises water and an unknown concentration of microalgae and zooplankton from the zooplankton culture system;

wherein the pump is configured to move the first sample and the second sample into and out of the sample tube;

wherein the photodetector is configured to output a first signal while the first sample is in the sample tube, and a second signal while the second sample is in the sample tube;

wherein the digital storage device is configured capture and store the value of the first and second signals; and

wherein the microprocessor is configured to calculated the concentration of zooplankton in the second sample by calculating the difference between the first signal and the second signal.

2. The system of claim 1, wherein the pump is an airlift pump.

3. The system of claim 1, wherein the sample tube is a quartz tube.

4. The system of claim 1, wherein the light source is an LED light source.

5. The system of claim 1, wherein the light source and photodetector are a transmissiometer.

6. The system of claim 5, wherein a turbidity meter is substituted for the transmissiometer.

7. The system of claim 1, wherein the zooplankton from the zooplankton culture system are selected from one of Sub-Phylum Crustacea, order Cladoceran, Sub-Phylum Crustacea, sub-class Copepoda, and Brine shrimp.

8. The system of claim 1, wherein the photodetector is selected from one of a photoresistor, a photovoltaic cell, a photodiode, and a phototransistor.

9. A method for calculating the concentration of zooplankton in a zooplankton culture system, comprising:

positioning a light source and a photodetector on opposite sides of a sample tube;

moving a first sample comprising water and an unknown concentration of microalgae into the sample tube via a pump and activating the light source;

recording a value of the photodetector output to a digital storage device as a first signal;

moving the first sample out of the sample tube via the pump;

moving a second sample comprising water and an unknown concentration of microalgae and zooplankton into the sample tube via the pump and activating the light source;

recording a second value of the photodetector output to the digital storage device as a second signal; and

calculating the difference between the first signal and the second signal using a microprocessor.

10. The method of claim 9, wherein the pump is an airlift pump.

11. The method of claim 9, wherein the sample tube is a quartz tube.

12. The method of claim 9, wherein the light source is an LED light source.

13. The method of claim 9, wherein the light source and photodetector are a transmissiometer.

14. The method of claim 13, wherein a turbidity meter is substituted for the transmissiometer.

15. The method of claim 9, wherein the zooplankton from the zooplankton culture system are selected from one of Sub-Phylum Crustacea, order Cladoceran, Sub-Phylum Crustacea, sub-class Copepoda, and Brine shrimp.

16. The method of claim 9, wherein the photodetector is selected from one of a photoresistor, a photovoltaic cell, a photodiode, and a phototransistor.

17. A system for monitoring zooplankton concentration in a zooplankton culture system, comprising:

a light source, a photodetector, and a sample tube, wherein the light source and the photodetector are positioned on opposite sides of the sample tube such that the photodetector is positioned to detect the light emitted from the light source through the sample tube;

a sample comprising water and an unknown concentration of microalgae and zooplankton from the zooplankton culture system;

a pump configured to move the sample into and out of the sample tube;

a digital storage device; and

a microprocessor,

wherein the photodetector is configured to output a signal while the first sample is in the sample tube;

wherein the digital storage device is configured capture and store a plurality of values of the signal; and

wherein the microprocessor is configured to estimate the concentration of zooplankton in the culture system as a function of the rate of decrease of the signal over time across at least one feed cycle, wherein a feed cycle is the time from the introduction of a first microalgae feed into the culture system and a second microalgae feed into the culture system.

18. The system of claim 17, wherein the pump is an airlift pump.

19. The system of claim 17, wherein the sample tube is a quartz tube.

20. The system of claim 17, wherein the light source is an LED light source.

21. The system of claim 17, wherein the light source and photodetector are a transmissiometer.

22. The system of claim 21, wherein a turbidity meter is substituted for the transmissiometer.

23. The system of claim 17, wherein the zooplankton from the zooplankton culture system are selected from one of Sub-Phylum Crustacea, order Cladoceran, Sub-Phylum Crustacea, sub-class Copepoda, and Brine shrimp.

24. The system of claim 17, wherein the photodetector is selected from one of a photoresistor, a photovoltaic cell, a photodiode, and a phototransistor.

25. A method for calculating the concentration of zooplankton in a zooplankton culture system, comprising:

a) positioning a light source and a photodetector on opposite sides of a sample tube;

b) moving a sample comprising water and an unknown concentration of microalgae and zooplankton into the sample tube via a pump and activating the light source;

c) recording a value of the photodetector output to a digital storage device as a signal;

d) moving the sample out of the sample tube via the pump;

e) periodically repeating steps b)-d) at least two times during a feed cycle; and

,

f) calculating the zooplankton concentration as a function of the rate of change of the signal over time using a microprocessor,

wherein a feed cycle is the time from the introduction of a first microalgae feed into the culture system and a second microalgae feed into the culture system, and

wherein the microprocessor is configured to calculate the zooplankton concentration as a function of the rate of change of the signal over time.

26. The method of claim 25, wherein the pump is an airlift pump.

27. The method of claim 25, wherein the sample tube is a quartz tube.

28. The method of claim 25, wherein the light source is an LED light source.

29. The method of claim 25, wherein the light source and photodetector are a transmissiometer.

30. The method of claim 29, wherein a turbidity meter is substituted for the transmissiometer.

31. The method of claim 25, wherein the zooplankton from the zooplankton culture system are selected from one of Sub-Phylum Crustacea, order Cladoceran, Sub-Phylum Crustacea, sub-class Copepoda, and Brine shrimp.

32. The method of claim 25, wherein the photodetector is selected from one of a photoresistor, a photovoltaic cell, a photodiode, and a phototransistor.

33. A method for harvesting zooplankton from a continuous zooplankton culture system, comprising:

a) defining a zooplankton concentration setpoint, wherein said setpoint is a value at which zooplankton are harvested from the zooplankton culture system;

b) defining a harvest duration variable;

c) defining a harvest gain variable;

d) defining a minimum harvest duration variable;

e) defining a maximum harvest duration variable;

f) calculating the current zooplankton concentration in the zooplankton culture system by positioning a light source and a photodetector on opposite sides of a sample tube;

moving a first sample comprising water and an unknown concentration of microalgae into the sample tube via a pump and activating the light source;

recording a value of the photodetector output to a digital storage device as a first signal;

moving the first sample out of the sample tube via the pump;

moving a second sample comprising water and an unknown concentration of microalgae and zooplankton into the sample tube via the pump and activating the light source;

recording a second value of the photodetector output to the digital storage device as a second signal; and

calculating the difference between the first signal and the second signal using a microprocessor;

g) if the current zooplankton concentration is less than the setpoint of step a), increasing the harvest duration variable by the difference between the setpoint and the current concentration multiplied by the harvest gain variable to define a modified harvest duration variable;

h) if the current zooplankton concentration is not less than the setpoint of step a), decreasing the harvest duration by the difference between the setpoint and the current concentration multiplied by the harvest gain variable to define a modified harvest duration variable;

i) if the modified harvest duration variable is within the maximum and minimum harvest duration variables of steps d) and e), harvesting the zooplankton for said modified harvest duration;

j) if the harvest duration is not within the maximum and minimum harvest duration variables of steps d) and e), harvesting the zooplankton for the harvest duration variable of step b); and

k) returning to step f).

34. A method for harvesting zooplankton from a continuous zooplankton culture system, comprising:

a) defining a zooplankton concentration setpoint, wherein said setpoint is a value at which zooplankton are harvested from the zooplankton culture system;

b) defining a harvest duration variable;

c) defining a harvest gain variable;

d) defining a minimum harvest duration variable;

e) defining a maximum harvest duration variable;

f) calculating the current zooplankton concentration in the zooplankton culture system by positioning a light source and a photodetector on opposite sides of a sample tube;

moving a sample comprising water and an unknown concentration of microalgae and zooplankton into the sample tube via a pump and activating the light source;

recording a value of the photodetector output to a digital storage device as a signal;

moving the sample out of the sample tube via the pump;

periodically a value of the photodetector output to a digital storage device as a signal in this manner at least two times during a feed cycle; and

, calculating the zooplankton concentration as a function of the rate of change of the signal over time using a microprocessor, wherein a feed cycle is the time from the introduction of a first microalgae feed into the culture system and a second microalgae feed into the culture system, and wherein the microprocessor is configured to calculate the zooplankton concentration as a function of the rate of change of the signal over time.

g) if the current zooplankton concentration is less than the setpoint of step a), increasing the harvest duration variable by the difference between the setpoint and the current concentration multiplied by the harvest gain variable to define a modified harvest duration variable;

h) if the current zooplankton concentration is not less than the setpoint of step a), decreasing the harvest duration by the difference between the setpoint and the current concentration multiplied by the harvest gain variable to define a modified harvest duration variable;

i) if the modified harvest duration variable is within the maximum and minimum harvest duration variables of steps d) and e), harvesting the zooplankton for said modified harvest duration;

j) if the harvest duration is not within the maximum and minimum harvest duration variables of steps d) and e), harvesting the zooplankton for the harvest duration variable of step b); and

k) returning to step f).