Apparatus and method for studying the sinking rate of small and medium-sized zooplankton feces

Abstract

The application discloses a method for studying the sinking rate of small and medium-sized zooplankton fecal particles, and comprises the following steps: step one, pulling the piston of a syringe to the initial scale of the extraction state; step two, injecting seawater into a sinking tube, and putting the small and medium-sized zooplankton fecal particles into the surface of the water body of the sinking tube; step three, opening the upper water outlet switch, and recording the time T0 at the same time, and collecting with a centrifugal tube; step four, opening the lower water outlet switch after several minutes, and recording the time T1 at the same time, and collecting with a centrifugal tube; step five, counting the density of the fecal particles under a microscope; step six, measuring the vertical distance (L) between the upper and lower water outlets; and step seven, calculating the average sinking rate (S, unit: cm / min) of the fecal particles according to the formula. The sinking rate of the fecal particles is calculated by combining the distance and the time consumption, and the problem that the sinking rate of the small and medium-sized zooplankton fecal particles cannot be directly measured by a conventional observation method is solved.

Description

Technical Field

[0001] This invention relates to the field of research on the settling rate of zooplankton feces, and specifically to an apparatus and method for studying the settling rate of feces from small and medium-sized zooplankton. Background Technology

[0002] Medium-sized zooplankton include copepods and cladocerans in both freshwater and seawater, while small zooplankton refers to ciliates and radiolarians in both freshwater and seawater. The vast number of zooplankton in aquatic ecosystems participate in the formation of particulate carbon and its transport from the water surface to the bottom through various physiological processes, making them major contributors to the biological pump. Zooplankton feces account for a significant share of the vertical carbon flux in water bodies, and their function in water carbon neutrality has become a research hotspot in recent years. The conventional method for measuring the settling of aquatic animal fecal particles is to directly observe the settling of fecal particles in a cylindrical transparent container, record the vertical settling distance and time, and then calculate the settling rate. Because the fecal particles of small to medium-sized zooplankton such as copepods, cladocerans, and protozoa are small (length <150 micrometers, diameter <40 micrometers) and difficult to see with the naked eye, it is difficult to directly observe their settling process using conventional methods. Therefore, measuring or calculating their settling rate remains a challenge, and there is an urgent need for a device specifically designed for studying the settling of feces from small to medium-sized zooplankton. This invention fills this technological gap and will facilitate the widespread development of research on the settling of feces from small to medium-sized zooplankton. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings and deficiencies of the prior art and to provide a method for studying the settling rate of feces of small and medium-sized zooplankton.

[0004] Another objective of this invention is to provide a method for studying the settling rate of feces from small and medium-sized zooplankton.

[0005] This invention is achieved through the following technical solution:

[0006] An apparatus for studying the settling rate of feces from small and medium-sized zooplankton includes a longitudinally arranged settling tube. A sealing plug is provided at the top of the settling tube, and a connector is installed on the sealing plug. The connector extends to the top of the settling tube and is connected to a syringe via a connecting tube. An upper outlet with an upper outlet switch is provided at the upper part of the settling tube, a lower outlet with a lower outlet switch is provided at the lower part of the settling tube, and a bottom outlet with a bottom outlet switch is provided at the bottom of the settling tube.

[0007] Furthermore, the sealing plug is a silicone sealing plug, and the sealing plug has a through hole for the connector to pass through, and the connector fits tightly with the sealing plug.

[0008] Furthermore, the settling pipe is an acrylic settling pipe, and the settling pipe is arranged in a long cylindrical shape.

[0009] Furthermore, the ratio of the inner diameter of the upper outlet to the inner diameter of the settling pipe is <1:5, the ratio of the inner diameter of the lower outlet to the inner diameter of the settling pipe is <1:5, the bottom of the settling pipe gradually decreases in size from top to bottom, and the bottom of the settling pipe is set in an inverted conical shape.

[0010] Furthermore, the upper water outlet is connected to an upper rubber tube, and the upper rubber tube is equipped with an upper clamp.

[0011] Furthermore, the lower outlet is connected to a lower rubber tube, and the lower rubber tube is equipped with a lower clamp.

[0012] Furthermore, the bottom outlet is connected to a bottom rubber tube, and the bottom rubber tube is equipped with a bottom clamp.

[0013] A method for studying the settling rate of feces from small and medium-sized zooplankton includes the following steps:

[0014] Step 1: Prepare the settling tube, sealing plug, and syringe. Connect the sealing plug and syringe. Close the upper outlet switch, lower outlet switch, and bottom outlet switch of the settling tube. Pull the piston of the syringe to the initial mark of the extraction state.

[0015] Step 2: The seawater filtered through the filter membrane is injected into the settling pipe to collect the complete fecal particles produced by small and medium-sized zooplankton. These particles are then placed on the surface of the water in the settling pipe and immediately sealed with a plug.

[0016] Step 3: Open the upper outlet valve and record the time T0. Slowly push the syringe piston to the middle mark, which is half the value of the initial mark. Water sample will flow out of the upper outlet. After collecting the sample with a centrifuge tube, close the upper outlet valve.

[0017] Step 4: After a few minutes, open the lower outlet valve and note the time T1. Slowly push the syringe plunger to the bottom. Water sample will flow out of the lower outlet. After collecting the sample with a centrifuge tube, close the lower outlet valve.

[0018] Step 5: Fix the fecal particles with glutaraldehyde and count the density of the fecal particles under a microscope;

[0019] Step 6: Measure the vertical distance (L) between the upper and lower water outlets;

[0020] Step 7: Calculate the average settling velocity of fecal particles (S, unit: cm / min) according to the formula:

[0021]

[0022] in:

[0023] N s Fecal particle density at the lower outlet (particles / ml);

[0024] N t : Fecal particle density at the top outlet (particles / ml);

[0025] L: Settlement distance (cm);

[0026] T0: Time for collecting samples at the water inlet;

[0027] T1: Time for collecting samples at the drain outlet.

[0028] Compared to existing technologies, this invention determines the settling of fecal particles by monitoring the density of fecal particles in water samples from the upper and lower outlets. The rate of change in fecal particle density is used as a factor to estimate the average settling rate. Because small and medium-sized zooplankton fecal particles are easily broken and fragmented by external forces, a syringe can be used to propel water within a closed system, thereby controlling the outflow velocity of samples from the upper and lower outlets. This avoids the situation where excessive water flow in the connected system disperses the fecal particles and also prevents the natural settling process of the fecal particles from being affected by sample outflow. It cleverly transforms direct observation into tracking the change in particle density as fecal particles sink in the water, and calculates the settling rate of the feces by combining distance and time, solving the problem that conventional observation methods cannot directly measure the settling rate of small and medium-sized zooplankton fecal particles. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the device for measuring the settling rate of small zooplankton feces in this invention.

[0031] In the diagram: 1-settling pipe; 2-sealing plug; 3-connector; 4-syringe; 5-upper outlet; 6-lower outlet; 7-bottom outlet; 8-upper rubber tube; 9-upper clamp; 10-lower rubber tube; 11-lower clamp; 12-bottom rubber tube; 13-bottom clamp. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] like Figure 1 The apparatus shown in this invention for studying the settling rate of small and medium-sized zooplankton feces includes a longitudinally arranged settling tube 1. A sealing plug 2 is installed at the top of the settling tube 1, and a connector 3 is installed on the sealing plug 2. The connector 3 extends to the top of the settling tube 1 and is connected to a syringe 4 via a connecting tube. The upper part of the settling tube 1 has an upper outlet 5 with an upper outlet switch. The lower part of the settling tube 1 has a lower outlet 6 with a lower outlet switch. The bottom of the settling tube 1 has a bottom outlet 7 with a bottom outlet switch. The syringe 4 controls the internal pressure, water velocity, and volume. The upper and lower outlets 5 and 6 control the upper and lower water outputs, respectively, while the bottom outlet 7 controls the bottom water output. This apparatus is used for washing the settling tube 1 and releasing residual water.

[0034] The sealing plug 2 is a silicone sealing plug. The sealing plug 2 has a through hole for the connector 3 to pass through. The connector 3 and the sealing plug 3 fit tightly together, which improves the sealing performance of the connection of the sealing plug 2.

[0035] As one specific implementation method, the settling pipe 1 is an acrylic settling pipe, and the settling pipe 1 is arranged in a long cylindrical shape.

[0036] The ratio of the inner diameter of the upper outlet 5 to the inner diameter of the sedimentation pipe 1 is <1:5, and the ratio of the inner diameter of the lower outlet 6 to the inner diameter of the sedimentation pipe 1 is <1:5. This can moderately control the water discharge speed and facilitate collection. The bottom of the sedimentation pipe 1 gradually decreases from top to bottom, and the bottom of the sedimentation pipe 1 is set in an inverted conical shape to facilitate the release of the remaining water in the sedimentation pipe 1.

[0037] The upper outlet 5 is connected to an upper rubber tube 8, which is equipped with an upper clamp 9. The upper clamp 9 is used to control the opening and closing of the upper rubber tube 8, so as to facilitate the control of the water output from the upper outlet 5.

[0038] The lower outlet 6 is connected to a lower rubber tube 10, which is equipped with a lower clamp 11. The lower clamp 11 is used to control the opening and closing of the lower rubber tube 10, so as to facilitate the control of the water output from the lower outlet 6.

[0039] A bottom outlet 7 is connected to a bottom rubber tube 12. The bottom rubber tube 12 is equipped with a bottom clamp 13, which is used to control the opening and closing of the bottom rubber tube 12, so as to facilitate the control of water output from the bottom outlet 7.

[0040] A method for studying the settling rate of feces from small and medium-sized zooplankton includes the following steps:

[0041] Step 1: Prepare settling tube 1, sealing plug 2 and syringe 4. Connect sealing plug 2 and syringe 4. Close the upper outlet switch, lower outlet switch and bottom outlet switch of settling tube 1. Pull the piston of syringe 4 to the initial scale of the extraction state.

[0042] Step 2: The seawater filtered through the filter membrane is injected into the settling pipe 1 to collect the complete fecal particles produced by small and medium-sized zooplankton. The fecal particles are then placed on the surface of the water in the settling pipe 1 and the sealing plug 2 is immediately tightened.

[0043] Step 3: Open the upper outlet switch and record the time T0. Slowly push the piston of syringe 4 to the middle mark, which is half the value of the initial mark. Water sample will flow out of the upper outlet. After collecting the sample with a centrifuge tube, close the upper outlet switch.

[0044] Step 4: After a few minutes, open the lower outlet valve and note the time T1. Slowly push the piston of syringe 4 to the bottom. Water sample will flow out of the lower outlet. After collecting the sample with a centrifuge tube, close the lower outlet valve.

[0045] Step 5: Fix the fecal particles with glutaraldehyde and count the density of the fecal particles under a microscope;

[0046] Step 6: Measure the vertical distance (L) between the upper and lower water outlets;

[0047] Step 7: Calculate the average settling velocity of fecal particles (S, unit: cm / min) according to the formula:

[0048]

[0049] in:

[0050] N s Fecal particle density at the lower outlet (particles / ml);

[0051] N t : Fecal particle density at the top outlet (particles / ml);

[0052] L: Settlement distance (cm);

[0053] T0: Time for collecting samples at the water inlet;

[0054] T1: Time for collecting samples at the drain outlet. Specific Implementation

[0056] (1) Prepare sedimentation tube 1, sealing plug 2 and syringe 4. Connect sealing plug 2 and syringe 4. Close the upper outlet switch, lower outlet switch and bottom outlet switch of sedimentation tube 1. Pull the piston of syringe to the 40ml mark.

[0057] (2) 300 mL of seawater (filtered through a 0.22 μm filter membrane) was injected into the settling tube 1 (28 cm high, 3.9 cm inner diameter) to collect 100-150 complete fecal particles produced by the marine copepod Anisia pseudodart water flea and put them into the water surface of the settling tube 1. Immediately seal the plug 2 tightly.

[0058] (3) Loosen the upper clamp 9 of the upper outlet 5 and record the time T0. Slowly push the piston of the syringe 4 to 20mL. 20mL of water sample flows out of the upper outlet 5. Collect it in a 50mL centrifuge tube and clamp the upper clamp 9 of the upper outlet 5.

[0059] (4) After 9-10 minutes, loosen the lower clamp 11 of the lower outlet 6 and record the time T1. Slowly push the piston of the syringe 4 to the bottom. 20 mL of water sample flows out of the lower outlet 6 and is collected in a 50 mL centrifuge tube. Then tighten the lower clamp 11 of the lower outlet 6.

[0060] (5) Fix fecal particles with glutaraldehyde (final concentration of 1%) and count them under a microscope;

[0061] (6) Measure the vertical distance (L) between the upper and lower water outlets;

[0062] (7) Calculate the average settling velocity of fecal particles (S, unit: cm / min) according to the formula.

[0063] This invention determines the settling of fecal particles by monitoring the density of fecal particles in water samples from the upper and lower outlets. The rate of change in fecal particle density is used as a factor to estimate the average settling rate. Because small and medium-sized zooplankton fecal particles are easily broken or fragmented by external forces, a syringe can be used to propel water within a closed system, thereby controlling the outflow velocity of samples from the upper and lower outlets. This avoids the situation where excessive water flow in the connected system disperses the fecal particles and also prevents the natural settling process of the fecal particles from being affected by sample outflow. It cleverly transforms direct observation into tracking the change in particle density as fecal particles sink in the water, and calculates the settling rate of the feces by combining distance and time, solving the problem that conventional observation methods cannot directly measure the settling rate of small and medium-sized zooplankton fecal particles.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for studying the settling rate of feces from small and medium-sized zooplankton, characterized in that: A device for studying the settling rate of feces from small and medium-sized zooplankton is used. The device includes a longitudinally arranged settling tube, a sealing plug at the top of which is fitted with a connector extending to the top of the settling tube. The connector is connected to a syringe via a connecting tube. The upper part of the settling tube has an upper outlet with a switch, and the lower part has a lower outlet with a switch. The bottom of the settling tube has a bottom outlet with a switch. The ratio of the inner diameter of the upper outlet to the inner diameter of the settling tube is <1:5, and the ratio of the inner diameter of the lower outlet to the inner diameter of the settling tube is <1:

5. The bottom of the settling tube gradually tapers from top to bottom and is shaped like an inverted cone. The method includes the following steps. Step 1: Prepare the settling tube, sealing plug, and syringe. Connect the sealing plug and syringe. Close the upper outlet switch, lower outlet switch, and bottom outlet switch of the settling tube. Pull the piston of the syringe to the initial mark of the extraction state. Step 2: The seawater filtered through the filter membrane is injected into the settling pipe to collect complete fecal particles produced by small and medium-sized zooplankton. These particles are then placed on the surface of the water in the settling pipe and immediately sealed with a plug. Step 3: Open the upper outlet valve and record the time T0. Slowly push the syringe piston to the middle mark, which is half the value of the initial mark. Water sample will flow out of the upper outlet. After collecting the sample with a centrifuge tube, close the upper outlet valve. Step 4: After a few minutes, open the lower outlet valve and note the time T1. Slowly push the syringe plunger to the bottom. Water sample will flow out of the lower outlet. After collecting the sample with a centrifuge tube, close the lower outlet valve. Step 5: Fix the fecal particles with glutaraldehyde and count the density of the fecal particles under a microscope; Step Six: Measure the vertical distance L between the upper and lower water outlets; Step 7: Calculate the average settling velocity S of fecal particles using the following formula: S=(N) s / N t )×(L / (T1-T0)); in: S: Average settling velocity of fecal particles, in centimeters per minute; N s Fecal particle density at the lower outlet, in units of particles / ml; N t : Fecal particle density at the top outlet, in units of particles / ml; L: The vertical distance between the upper and lower outlets, i.e., the settlement distance, in centimeters; T0: The time when samples are collected at the upper outlet; T1: The time when samples are collected at the lower outlet.

2. The method for studying the settling rate of feces of small and medium-sized zooplankton according to claim 1, characterized in that: The sealing plug is a silicone sealing plug, and the sealing plug has a through hole for the connector to pass through, and the connector fits tightly with the sealing plug.

3. The method for studying the settling rate of feces of small and medium-sized zooplankton according to claim 1, characterized in that: The settling pipe is an acrylic settling pipe, and the settling pipe is arranged in a long cylindrical shape.

4. The method for studying the settling rate of feces of small and medium-sized zooplankton according to claim 1, characterized in that: The upper water outlet is connected to an upper rubber tube, and the upper rubber tube is equipped with an upper clamp.

5. The method for studying the settling rate of feces of small and medium-sized zooplankton according to claim 1, characterized in that: The lower outlet is connected to a lower rubber tube, and the lower rubber tube is equipped with a lower clamp.

6. The method for studying the settling rate of feces of small and medium-sized zooplankton according to claim 1, characterized in that: The bottom outlet is connected to a bottom rubber tube, and the bottom rubber tube is equipped with a bottom clamp.

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