JP2007120992A - Sea-bottom oxygen consumption measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sea-bottom oxygen consumption measuring device miniaturizable by arranging properly various measuring instruments, wherein the shielding rate to an oxygen concentration measuring chamber is suppressed low. <P>SOLUTION: A lifting device 10 for lifting a transparent cylindrical body 12 whose bottom surface and partial upper surface are opened is fixed approximately on the center of the upper surface formed by four upper side frames of a frame skeleton 20, and on an installation frame 25 installed between a pair of upper side frames. A transparent disk 11 are supported horizontally approximately on the center of the bottom surface formed by four bottom side frames, and on upper ends of a plurality of struts 40 erected on an installation frame 30 installed between a pair of bottom side frames 26, 28. When the cylindrical body 12 is lowered, the transparent disk 11 functions as the upper surface of the cylindrical body 12 to form the oxygen concentration measuring chamber 13. An optical dissolved oxygen meter 51 for measuring the dissolved oxygen quantity in the oxygen concentration measuring chamber 13 and an agitation device 15 for chamber inside agitation are arranged on the transparent disk 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an apparatus for measuring oxygen consumption at the bottom of the sea, and more specifically, it is so small that it is not necessary to equip a ship with a winch, and from the difference in the oxygen consumption rate between day and night with a low light shielding rate for the oxygen concentration measurement room. The present invention relates to an apparatus for measuring oxygen consumption in the sea that enables estimation of the amount of photosynthesis by benthic microalgae.

  The amount of dissolved oxygen in seawater plays an extremely important role in the material circulation in the bay and the maintenance of a healthy ecosystem. For example, one of the main factors that have deteriorated the sediment environment in Ago Bay in recent years is that the oxygen balance in the back of the bay collapses in the summer and the bottom layer becomes hypoxic. Therefore, it is extremely important to understand the behavior of oxygen in order to improve the environment in bays such as Ago Bay.

  To this end, the bay environment monitoring system constantly monitors the amount of dissolved oxygen in the sea, and as part of the development of technology for promoting material circulation, the development of technology for supplementing oxygen to the sea floor using the photosynthetic capacity of benthic microalgae is promoted. In addition, when evaluating the functions of benthic microalgae, it is necessary to ascertain the oxygen consumption and production on the surface of the seabed as close to the site as possible.

  As a method of measuring the oxygen consumption rate on the bottom mud surface, the bottom mud has been collected together with bottom layer water in a columnar container etc. and placed indoors in a sealed state to measure the amount of oxygen reduction in the container. A method has been used in which a vessel equipped with an oxygen concentration measuring chamber with an oxygen electrode called a bell jar is taken down and the amount of oxygen decrease is measured on site. However, the former has a problem that it is different from the on-site conditions by taking columnar mud and raising it to land. On the other hand, the latter bell jar method is superior in terms of on-site measurement, but because it measures in a sealed state for a long time, there is a problem that it differs from the on-site conditions where water is constantly exchanged by the flow of seawater. .

  In order to solve such problems, the National Institute of Advanced Industrial Science and Technology (AIST) first installed on the seabed and periodically lifted and lowered the oxygen consumption measurement chamber (oxygen concentration measurement room) An observation instrument that can continuously and directly measure the oxygen consumption rate at the sea floor was developed and commercialized by Alec Electronics Co., Ltd. under the trade name ADO2000. This device can electronically control the chamber up / down time, measurement interval, flow rate in the chamber, etc., enabling measurement in an extremely close environment.

However, the above-mentioned ADO2000, which is an oxygen consumption measuring device for the sea floor, has an installation area of 1 m ² or more, a height of about 1.5 m, and a weight of 45 kg. There was a problem with it. In addition, in order to measure the amount of oxygen generated by photosynthesis, it is necessary that the same amount of light as that reaching the sea floor reaches the inside of the chamber. However, although the ADO2000 is an acrylic transparent chamber, this chamber Since a large number of lifting shafts and various sensors are arranged at the top, there is also a problem that the light shielding rate is high.

  Accordingly, an object of the present invention is to provide a seabed oxygen consumption measuring device that can be miniaturized by appropriately arranging various measuring instruments and that has a low light shielding rate with respect to the oxygen concentration measuring chamber.

  In order to solve the above-described problem, the seabed oxygen consumption measuring device according to the present invention includes a substantially square upper surface formed by four upper frames of a frame skeleton framed in a substantially square shape and a pair of upper frames. An elevating device for elevating the transparent cylindrical body whose bottom surface and part of the upper surface are open is fixed to the erected frame, and is substantially at the center of the bottom surface formed by the four bottom frames, and a pair of A transparent disk is horizontally supported on the upper ends of a plurality of support columns installed between the bottom frames, and the cylindrical body descends, so that the transparent disk becomes the upper surface of the cylindrical body. An oxygen concentration measurement chamber is formed, and an optical dissolved oxygen meter for measuring the amount of dissolved oxygen in the oxygen concentration measurement chamber and a stirrer for stirring the chamber are disposed on the transparent disk. Specially It is an.

  In the seabed oxygen consumption measuring device of the present invention, acrylic resin can be suitably used as the transparent cylindrical body and the transparent disk. Further, a water quality meter for measuring the water quality in the oxygen concentration measurement chamber may be disposed on the transparent disk. Further, an optical dissolved oxygen meter, a water temperature salinity meter, a wiper photon meter, and a chlorophyll turbidimeter are installed on a construction frame constructed between a pair of vertical frames of the frame skeleton so as not to shield the oxygen concentration measurement chamber. At least one can be suitably mounted. Further, in this case, another installation frame is installed between the pair of vertical frames so as to face the installation frame installed between the pair of vertical frames, and a battery case is suitably used for the other installation frame. Can be installed.

  According to the present invention, it is possible to provide a seabed oxygen consumption measuring apparatus that can be downsized by appropriately arranging various measuring instruments and that has a low light shielding rate with respect to the oxygen concentration measuring chamber. According to this apparatus, since the light shielding rate with respect to the oxygen concentration measurement chamber is low, it is possible to estimate the photosynthesis amount (basic production amount) by benthic microalgae from the difference in the oxygen consumption rate between day and night. Moreover, it is extremely effective not only for the study of benthic microalgae, but also for measuring the oxygen consumption rate on the seabed surface widely. Furthermore, by solving the problem of shading, operation on tidal flats with a high proportion of direct light becomes possible. In particular, in tidal flats, oxygen is generated at the same time so as to offset the oxygen consumption of the seabed sediment, so that the actual oxygen consumption can be measured by using the apparatus of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a seabed oxygen consumption measuring device according to a preferred embodiment of the present invention. In this apparatus 1, a frame skeleton 20 is framed in a substantially square shape. The elevating device 10 is fixed to an erection frame 25 that is erected between the pair of upper side frames 21 and 23 at the approximate center of the upper surface formed by the four frames 21 to 24 on the upper side of the frame 20. The erection frame 25 is preferably formed by a pair of erection frames 25a and 25b as shown in the figure so that the lifting device can be stably fixed.

  In addition, a plurality of support columns 40 provided upright on a pair of installation frames 30a and 30b provided between the pair of bottom frames 26 and 28 at the approximate center of the bottom surface formed by the four bottom frames 26 to 29. A transparent disc, preferably an acrylic transparent plate 11, is supported horizontally at the upper end of the plate. Here, in order to ensure the support of the acrylic transparent plate 11, as shown in the figure, a pair of frames 31a and 31b are installed between the pair of installation frames 30a and 30b, and the frames 30a and 30b and 31a and Each column 31b is provided with a column, preferably an acrylic transparent column 40. Although not shown in the drawings, a support for fixing the support may be formed at a substantially central portion of the installation frames 30a, 30b, 31a and 31b.

  When the transparent cylindrical body 12 is lowered by the elevating device 10, the acrylic transparent plate 11 becomes the upper surface of the transparent cylindrical body 12 and forms the oxygen concentration measurement chamber 13. An optical dissolved oxygen meter 14 for measuring the amount of dissolved oxygen in the oxygen concentration measuring chamber 13 and a stirring device 15 for stirring the chamber are provided on the peripheral edge of the acrylic transparent plate 11. . As shown in the figure, the light shielding rate of the oxygen concentration measurement chamber 13 can be kept low by setting both of them upright. Although not shown, a water quality meter may be further provided on the acrylic transparent plate 11 depending on the application.

  The upper part of the transparent cylindrical body 12 is partially opened (a hole is provided) so that the upper surface of the cylindrical body 12 does not hit the standing optical dissolved oxygen meter 14 and the stirring device 15 when moving up and down. . The optical dissolved oxygen meter 14, the stirring device 15, and the water quality meter (not shown) can all adopt known ones as appropriate, but the optical dissolved oxygen meter 14 achieves downsizing of the device 1. Therefore, COPAT-OPTOD (trade name) manufactured by Alec Electronics Co., Ltd. is preferable.

  By forming the oxygen concentration measurement chamber 13 by lowering the elevating device 10, for example, the sea bottom including the directly above water can be closed, and the oxygen concentration during the closed period can be measured by the optical dissolved oxygen meter 14. At this time, the oxygen concentration in the oxygen concentration measurement chamber 13 can be accurately measured by appropriately generating a flow rate by the stirring device 15.

  In the seabed oxygen consumption measuring device 1, an optical dissolved oxygen meter is installed on a pair of 36a and 36b installation frames installed between the pair of vertical frames 33 and 34 of the frame skeleton 20 so as not to shield the oxygen concentration measurement chamber 13 from light. 51, a water temperature salinity meter 52, a wiper-type photon meter 53, and a chlorophyll turbidity meter 54 are installed. In the example shown in the figure, all of these are mounted, but can be appropriately selected according to the measurement purpose. Each measuring device is self-recording, and each detected data can be processed by a data processing device in each measuring device and output as related data. In order to achieve downsizing of the seabed oxygen consumption measuring device 1, an optical dissolved oxygen meter (manufactured by Alec Electronics Co., Ltd., trade name COPACT-OPTOD), a water temperature salinity meter (manufactured by Alec Electronics Co., Ltd.) , Trade name COPACT-CT), wiper type photon meter (trade name COPACT-LW, manufactured by Alec Electronics Co., Ltd.) and chlorophyll turbidimeter (trade name COPACT-CLW, manufactured by Alec Electronics Co., Ltd.) are preferably used. . When these measuring devices are attached to the frame skeleton 20, it is important to arrange the oxygen concentration measurement chamber 13 below the frame skeleton 20 as illustrated in order to prevent light shielding.

  Further, in this case, it is possible to mount the battery case 55 on the pair of installation frames 37a and 37b provided between the pair of vertical frames 32 and 35 so as to face the mounting portion of the measuring device. It is preferable in terms of balance. In this case as well, the weight is placed below the frame skeleton 20. There are no particular restrictions on the manner of measurement equipment on the frame skeleton 20 and the device on the battery case, and known methods such as tightening and screwing can be appropriately employed.

  Although wiring etc. are abbreviate | omitted in FIG. 1, the raising / lowering time and measurement interval of the oxygen concentration measurement chamber 13 in the apparatus 1 and the flow rate in various measuring devices and the oxygen concentration measurement chamber 13 can be electronically controlled from the outside. Such electronic control itself can employ the same control system as in the case of the above-mentioned ADO2000. For example, each observation item data is stored in a memory in an independent observation device, and each observation device can be synchronized with a personal computer clock when connected to a personal computer for data synchronization. Further, since the optical dissolved oxygen meter 14 in the oxygen concentration measurement chamber 13 is closely related to the opening / closing operation, it is necessary to strictly perform opening / closing and data acquisition of the optical dissolved oxygen meter 14.

  Triangular pyramids are formed by four frames 41 at four corners of the frames 21 to 24 on the upper side of the seabed oxygen consumption measuring device 1 so that the device 1 can be suspended. Is fixed. Thereby, installation to the seabed of apparatus 1 can be performed easily.

Hereinafter, specific measurement by the above-described seabed oxygen consumption measuring device of the present invention will be described.
The seabed oxygen consumption measuring device 1 shown in FIG. 1 was used, where the diameter of the transparent cylinder was 29 cm, the height was 15 cm, and the lifting stroke was 12 cm. In addition, an optical dissolved oxygen meter 51, a water temperature salinity meter 52, a wiper photon meter 53, and a chlorophyll turbidimeter 54 are provided on the pair of installation frames 36a and 36b so as not to shield the oxygen concentration measurement chamber 13. Installed. All the measuring instruments employed were those described above.

  The optical dissolved oxygen meter 51 is not an galvanic electrode that consumes oxygen but an optical dissolved oxygen meter, and the accuracy thereof is a resolution of 0.4% or less. The water temperature salinometer 52 has a water temperature accuracy of 0.05 ° C. or less and an electric conductivity accuracy of 0.05 mS / cm or less. The wiper type photon meter 53 is a photon meter that removes dirt for each measurement by a wiper. The chlorophyll turbidimeter 54 removes dirt with a wiper for each measurement, chlorophyll can measure a minimum of 0.1 ug / l by fluorescence measurement, and turbidity can measure infrared backscattering with a resolution of 0.03 FTU. .

  In addition, the device can be used at a water depth of 30 m, accommodates a rechargeable battery with a continuous operation time of 7 days or more in the battery case 55, and the stirring device 15 has a flow rate of 0, 1, 2, 3, 4, 5 cm / sec. The existing thing which can generate | occur | produce was used.

  The main body shape of the device 1 could be within 0.7 m lateral, 0.7 m wide, and 1.3 m high. The frame skeleton 20 considered the installation area for prevention of the sinking of this apparatus in soft mud ground. The weight of the apparatus 1 was within 30 kg. As a result, the weight of the known ADO2000 (manufactured by Alec Electronics Co., Ltd.) equipment is approximately 2/3 minutes of the weight of 37 kg, and the dimensions are also reduced compared to the dimensions of 1 m × 1 m × 1.4 m of ADO2000, and a large size with a winch. A ship is no longer needed.

FIG. 2 shows the relationship between time and oxygen concentration when the oxygen concentration measurement chamber 13 is alternately opened and closed. In FIG. 2, the closed period of the oxygen concentration measurement chamber 13 is shaded. One measurement is 10 minutes. It can be seen from FIG. 2 that when the oxygen concentration measurement chamber 13 is closed, the internal DO value decreases almost linearly, and when it is opened after 30 minutes, it quickly becomes equal to the outer DO value. The average consumption rate during this period was 77 ± 11 mg O ₂ m ⁻² h ⁻¹ .

1 is a partially cutaway perspective view of an apparatus according to a preferred embodiment of the present invention. It is a graph which shows the relationship between the time in oxygen concentration measurement chamber 13, and oxygen concentration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Seabed oxygen consumption measuring device 10 Lifting device 11 Acrylic transparent plate 12 Transparent cylindrical body 13 Oxygen concentration measuring chamber 14 Optical dissolved oxygen meter 15 Stirring device 20 Frame skeleton 21, 22, 23, 24 Frame 26, 27, 28, 29 Bottom frame 25a, 25b, 30a, 30b, 31a, 31b, 36a, 36b, 37a, 37b Construction frame 32, 33, 34, 35 Vertical frame 40 Support column 41 Frame 42 Ring 51 Optical dissolved oxygen meter 52 Water temperature salinity meter 53 Wiper type photon meter 54 Chlorophyll turbidimeter 55 Battery case

Claims (5)

  A transparent cylindrical body having a bottom surface and a partly upper surface open to a construction frame that is constructed at a substantial center of an upper surface formed by four upper side frames of a frame skeleton framed in a substantially square shape and is laid between a pair of upper side frames. The upper ends of a plurality of support columns that are fixed to a lifting frame for raising and lowering the frame, and that are substantially at the center of the bottom surface formed by the four bottom frames and are erected on a construction frame constructed between a pair of bottom frames. When the transparent disk is horizontally supported and the cylindrical body descends, the transparent disk becomes the upper surface of the cylindrical body to form an oxygen concentration measuring chamber, and the oxygen concentration measurement is performed on the transparent disk. An ocean bottom oxygen consumption measuring device, comprising: an optical dissolved oxygen meter for measuring the amount of dissolved oxygen in a room; and a stirrer for stirring the room.   The seabed oxygen consumption measuring device according to claim 1, wherein the transparent cylindrical body and the transparent disk are made of acrylic resin.   The seabed oxygen consumption measuring device according to claim 1 or 2, wherein a water quality meter for measuring water quality in the oxygen concentration measuring chamber is disposed on the transparent disk.   At least one of an optical dissolved oxygen meter, a water temperature salinity meter, a wiper photon meter, and a chlorophyll turbidimeter so that the oxygen concentration measurement chamber is not shielded from a frame constructed between a pair of vertical frames of the frame skeleton. The seabed oxygen consumption measuring device according to any one of claims 1 to 3, wherein one is installed.   2. Another construction frame is constructed between a pair of vertical frames opposite to the construction frame constructed between the pair of vertical frames, and a battery case is mounted on the other construction frame. The seabed oxygen consumption measuring device according to any one of?