APPARATUS AND METHOD FOR CULTURING SPHAGNUM

Abstract

An apparatus (100) for use in culturing Sphagnum (106) is provided. The apparatus (100) comprises a culture vessel (102) for Sphagnum (106) and a culture medium (104) arranged in the culture vessel (102). The culture vessel (102) comprises an enclosed airspace (108) above the culture medium (104), and Sphagnum (106) arranged in the culture medium (104). The apparatus (100) further comprises means (110, 112) for supplying carbon dioxide into the enclosed airspace (108).

Claims

1. An apparatus for use in culturing Sphagnum, comprising: a culture vessel for Sphagnum; a culture medium arranged in the culture vessel, wherein the culture vessel comprises an enclosed airspace above the culture medium; and Sphagnum arranged in the culture medium; wherein the apparatus is configured to supply carbon dioxide into the enclosed airspace.

2. The apparatus according to claim 1, wherein the apparatus is configured to supply a gas comprising at least 1% carbon dioxide by volume into the enclosed airspace.

3. The apparatus according to claim 1, wherein the apparatus is configured to supply a gas comprising at least 90% carbon dioxide by volume into the enclosed airspace.

4-6. (canceled)

7. The apparatus according to claim 1, further comprising a barrier permeable to carbon dioxide.

8. (canceled)

9. The apparatus according to claim 7, wherein the apparatus is configured to supply carbon dioxide through the barrier permeable to carbon dioxide and into the enclosed airspace.

10. The apparatus according to claim 7, wherein the barrier is arranged at least partially in contact with the enclosed airspace.

11. The apparatus according to claim 7, wherein the barrier is arranged at least partially within the culture vessel.

12. The apparatus according to claim 7, wherein the barrier comprises a tube permeable to carbon dioxide.

13. The apparatus according to claim 12, wherein the tube is arranged at least partially in the enclosed airspace.

14. The apparatus according to claim 12, further comprising an inlet pipe connected to a source of carbon dioxide, and wherein a first end of the tube is connected to the inlet pipe.

15. The apparatus according to claim 14, further comprising an outlet pipe connected to a second end of the tube.

16. The apparatus according to claim 1, wherein the culture medium does not comprise sugar.

17. The apparatus according to claim 1, wherein the culture medium comprises a liquid culture medium, and wherein the apparatus is configured to stir the liquid culture medium.

18. (canceled)

19. The apparatus according to claim 17, wherein the apparatus is configured to stir the culture medium from externally of the culture vessel.

20. The apparatus according to claim 17, further comprising a heat source configured to apply a temperature differential in the culture vessel to stir the liquid culture medium.

21. The apparatus according to claim 20, wherein the heat source comprises a light source.

22. The apparatus according to claim 1, further comprising a second culture vessel for Sphagnum and a second culture medium arranged in the second culture vessel, wherein the second culture vessel comprises a second enclosed airspace above the second culture medium, and further comprising Sphagnum arranged in the second culture medium; and wherein the apparatus is configured to supply carbon dioxide into the second enclosed airspace of the second culture vessel.

23. The apparatus according to claim 22, wherein the culture medium comprises a liquid culture medium, wherein the apparatus is configured to stir the liquid culture medium, wherein the second culture medium comprises a second liquid culture medium, and wherein the apparatus is further configured to stir the second liquid culture medium of the second culture vessel.

24. The apparatus according to claim 23, further comprising a heat source configured to apply a temperature differential in the culture vessel and the second culture vessel to stir the liquid culture medium and the second liquid culture medium, wherein the heat source comprises a light source, and wherein the light source is arranged between the culture vessel and the second culture vessel.

25-26. (canceled)

27. A method of culturing Sphagnum, comprising: providing a culture vessel for Sphagnum; providing a culture medium arranged in the culture vessel, wherein the culture vessel comprises an enclosed airspace above the culture medium; providing Sphagnum arranged in the culture medium; and supplying carbon dioxide into the enclosed airspace.

28-31. (canceled)

Description

[0229] Embodiments of the disclosure are described below, by way of example only, with reference to the accompanying Figures.

[0230] FIG. 1 shows a cross-sectional view of an apparatus for use in culturing Sphagnum, according to a first embodiment of the disclosure.

[0231] FIG. 2 shows a cross-sectional view of an apparatus for use in culturing Sphagnum, according to a second embodiment of the disclosure, having a permeable membrane.

[0232] FIG. 3 shows a cross-sectional view of an apparatus for use in culturing Sphagnum, according to a third embodiment of the disclosure, having a permeable tube.

[0233] FIG. 4 shows a cross-sectional view of an apparatus for use in culturing Sphagnum, according to a fourth embodiment of the disclosure, having a light source.

[0234] FIG. 5 shows a cross-sectional view of an apparatus for use in culturing Sphagnum, according to a fifth embodiment of the disclosure, comprising a second culture vessel and a shared light source.

[0235] FIG. 6 shows a plan view from above of an apparatus for use in culturing Sphagnum, according to a sixth embodiment of the disclosure, comprising a second, third, and fourth culture vessel and a shared light source.

[0236] FIG. 7 shows a photograph from the side of an experimental arrangement of a container with water to determine a temperature differential provided by the heating effect of a light source.

[0237] FIG. 8 shows a photograph from the side of an experimental arrangement of a container with water to determine convection currents provided by the heating effect of a light source, with droplets of ink placed into the water.

[0238] FIG. 9A shows a photograph from above of an experimental arrangement of a container with water to determine convection currents provided by the heating effect of a light source, with droplets of ink placed into the water.

[0239] FIG. 9B shows a photograph from above of the experimental arrangement of FIG. 9A, after a predetermined time period.

[0240] FIG. 9C shows a photograph from above of the experimental arrangement of FIG. 9B, after a predetermined time period.

[0241] FIG. 10 shows a photograph from the side of an apparatus for use in culturing Sphagnum in accordance with the disclosure.

[0242] FIG. 11 shows a photograph from the side of the apparatus of FIG. 10, after a period of 12 weeks of growth.

[0243] Referring to FIG. 1, according to a first embodiment of the disclosure, an apparatus 100 is provided. The apparatus 100 comprises a culture vessel 102. The culture vessel 102 is a cylindrical container having a circular cross-section, although other shapes of container are envisaged, such as a cube or cuboid. In the first embodiment, the culture vessel 102 is a container made from polypropylene. The culture vessel 102 is transparent, which allows for observation of Sphagnum and visual identification of contamination. The transparent culture vessel 102 also allows for supply of light into the container for photosynthesis. The culture vessel 102 has an interior volume of approximately 5 L, although other volumes are possible such as 2 L or 10 L. The 5 L culture vessel 102 has a height of approximately 195 mm and an upper diameter of about 225 mm.

[0244] The culture vessel 102 holds a liquid medium 104 and Sphagnum 106 within the liquid medium 104. In other embodiments, the culture vessel 102 holds a solid medium, for example solidified with agar, with Sphagnum resting on the upper surface of the solid medium. The liquid medium 104 is arranged inside the culture vessel 102, once the culture vessel 102 has been sterilised. In FIG. 1, the liquid medium 104 is shown to occupy approximately half of the volume of the culture vessel 102, although this is primarily to aid understanding of the disclosure. In other examples, the liquid medium 104 can occupy other proportions of the volume of the culture vessel 102, such as around 80% of the volume.

[0245] The liquid medium 104 is an aqueous solution comprising water. The liquid medium 104 also comprises nutrients for facilitating the cultivation of Sphagnum. In the first embodiment, the nutrients comprise nitrogen, phosphorus, potassium, calcium, magnesium, sodium, manganese, copper, zinc, sulfur, boron, iron, molybdenum, chlorine, cobalt, and iodine. Different levels of nutrients may be provided in other examples. In alternative examples, some nutrients may be omitted or other nutrients may be included. In the first embodiment, the liquid medium 104 does not comprise sugar (e.g. sucrose). Thus, the Sphagnum 106 is grown in the absence of sugar.

[0246] The culture vessel 102 comprises an airspace 108 above the liquid medium 104. The airspace 108 may otherwise be referred to as a headspace. The airspace 108 is a region of the interior volume of the culture vessel 102 in which the liquid medium 104 is not present. For example, if the liquid medium 104 occupies 80% of the volume, then the airspace occupies the remaining space, i.e. 20% of the volume. The airspace 108 is arranged above the liquid medium 104.

[0247] In the first embodiment, the Sphagnum 106 is in vitro Sphagnum. The Sphagnum 106 is in the form of strands of whole plants which have been micropropagated. This provides clean material which reduces contamination.

[0248] The apparatus 100 comprises a source of carbon dioxide 110. In the first embodiment, the source of carbon dioxide 110 is a bottle of compressed carbon dioxide. In the first embodiment, the source of carbon dioxide 110 is a cylinder of compressed carbon dioxide in liquid form, commercially available from BOC, UK. The source of carbon dioxide 110 is arranged to supply substantially pure (at least 99%) carbon dioxide. In some embodiments, the source of carbon dioxide 110 is arranged to supply a gas comprising at least 1% carbon dioxide by volume, preferably at least 2%, more preferably at least 3%, even more preferably at least 5%, still more preferably at least 50%, yet still more preferably at least 75%, and still further more preferably at least 90%.

[0249] The apparatus 100 also comprises an inlet pipe 112. The inlet pipe 112 is connected to the source of carbon dioxide 110. The inlet pipe 112 has an open end 114. The open end 114 is the opposite end of the inlet pipe 112 to the end connected to the source of carbon dioxide 110. The open end 114 is arranged to extend into the culture vessel 102. In other embodiments, the inlet pipe 112 comprises a plurality of serially connected pipes from the source of carbon dioxide 110 to the open end 114 arranged in the culture vessel 102.

[0250] The inlet pipe 112 is inserted into the culture vessel 102. In particular, the inlet pipe 112 is inserted through an inlet hole 116 in the wall of the culture vessel 102. In FIG. 1, the inlet hole 116 is in the upper surface of the culture vessel 102, but in other examples it may be in the side wall of the culture vessel 102. In other embodiments, the culture vessel 102 comprises a removable lid, in which case the inlet hole 116 may be in the removable lid. The inlet pipe 112 is inserted through the inlet hole 116 of the culture vessel 102 such that the open end 114 is arranged inside the culture vessel 102, and in particular in the airspace 108. The inlet hole 116 is substantially gas-tight sealed around the inlet pipe 112. Thus, the culture vessel 102 is isolated from the external environment and is sealed except through the connection to the source of carbon dioxide 110 through the inlet pipe 112. In this way, the airspace 108 is enclosed.

[0251] The source of carbon dioxide 110 is therefore in fluid communication with the airspace 108 through the inlet pipe 112. Carbon dioxide can be supplied from the source of carbon dioxide 110 to the airspace 108 of the culture vessel 102 via the inlet pipe 112. Arrow A in FIG. 1 indicates the flow of carbon dioxide from the inlet pipe 112 through the open end 114 and into the airspace 108.

[0252] The inlet pipe 112 is shown as an L-shape in FIG. 1 for illustrative purposes only, and the inlet pipe 112 may take any shape, and in the first embodiment is a flexible pipe. The inlet pipe 112 is impermeable to carbon dioxide. Thus, carbon dioxide entering the inlet pipe 112 at the source of carbon dioxide 110 will not leak through the walls of the inlet pipe 112, and will only exit through the open end 114. In the first embodiment, the inlet pipe 112 is made from nylon.

[0253] Although not illustrated in FIG. 1, in some examples, the inlet pipe 112 may comprise one or more valves for controlling the flow of carbon dioxide from the source of carbon dioxide 110.

[0254] In this arrangement, the apparatus 100 constitutes an apparatus for use in culturing the Sphagnum 106. The inlet pipe 112 provides the supply of carbon dioxide into the airspace 108. This allows the concentration of carbon dioxide in the airspace 108 to increase over time. The carbon dioxide in the airspace can be absorbed into the liquid medium 104 by diffusion. The rate of absorption is determined by the surface area of the liquid medium 104 in contact with the airspace 108. Due to the supply of carbon dioxide, and the lack of sugar in the liquid medium 104, the Sphagnum is provided with a carbon source for photosynthesis and risk of contamination is mitigated in accordance with the present disclosure.

[0255] In alternative embodiments, the apparatus 100 may further comprise an outlet pipe for removing gas from the airspace 108. This allows for the balancing of pressure within the airspace 108, and allows the airspace 108 to be replenished with carbon dioxide.

[0256] Referring to FIG. 2, according to a second embodiment of the disclosure, an apparatus 200 is provided. The apparatus 200 of the second embodiment may include one or more features described above in relation to the first embodiment. The same reference numerals are used to denote identical features.

[0257] The apparatus 200 of the second embodiment is similar to the apparatus 100 of the first embodiment shown in FIG. 1, except that the apparatus 200 further comprises a membrane 218. The membrane 218 is permeable to carbon dioxide. The membrane 218 is a barrier permeable to carbon dioxide. In the second embodiment, the membrane 218 is made from silicone rubber, although other materials may be used in other examples. The membrane 218 is arranged inside the culture vessel 102. In the second embodiment, the membrane 218 extends over the entire width of the culture vessel 102 such that the membrane 218 divides the volume of the culture vessel 102 into two regions (an upper region and a lower region). The membrane 218 extends perpendicularly to the height of the culture vessel 102, such that the membrane 218 is arranged substantially horizontally across the width of the culture vessel 102. The lower region contains the liquid medium 104 and the Sphagnum 106 therein. Therefore, the membrane 218 is arranged above the liquid medium 104. The membrane 218 is arranged in contact with the enclosed airspace which is defined between the liquid medium 104 and the membrane 218.

[0258] The inlet pipe 112 is inserted through the upper surface of the culture vessel 102 into the upper region above the membrane 218. Thus, the inlet pipe 112 supplies carbon dioxide into a region of the culture vessel 102 above the membrane 218.

[0259] The membrane 218 acts as a barrier to separate the liquid medium 104 from the source of carbon dioxide 110. The membrane 218 acts to filter the supplied carbon dioxide to ensure that contaminants are blocked from coming into contact with the liquid medium 104. Carbon dioxide can then diffuse across the membrane 218, while contaminants cannot pass across the membrane 218. This acts as a simple and convenient method of supplying carbon dioxide to the airspace 108, while providing additional protection against contamination. This can be more cost effective than supplying sterilised carbon dioxide.

[0260] In alternative embodiments, the membrane 218 may be arranged over the open end 114 of the inlet tube 112. For example, the membrane 218 may be in the form of a cap over the open end 114 of the inlet tube 112. This would then force the carbon dioxide to diffuse through the membrane 218 at the end of the inlet tube 112, isolating the airspace 108 from the source of carbon dioxide 110.

[0261] In other embodiments, the membrane 218 may be arranged as the lid of the culture vessel 102. Carbon dioxide can then be supplied through the membrane 218, such as by elevating carbon dioxide levels surrounding the culture vessel 102 (e.g. in the room, or in a container containing one or more culture vessels 102).

[0262] Referring to FIG. 3, according to a third embodiment of the disclosure, an apparatus 300 is provided. The apparatus 300 of the third embodiment may include one or more features described above in relation to the first or second embodiments. The same reference numerals are used to denote identical features.

[0263] The apparatus 300 of the third embodiment is similar to the apparatus 200 of the second embodiment shown in FIG. 2, except that the apparatus 300 comprises a tube 318 instead of the membrane 218. The tube 318 is a specific embodiment of a permeable barrier.

[0264] The apparatus 300 of the third embodiment differs from the first and second embodiments in that the open end 114 of the inlet pipe 112 does not open into the culture vessel 102. Instead, the tube 318 is arranged at least partially within the airspace 108 of the culture vessel 102. The tube 318 passes through the inlet hole 116 in the culture vessel 102. In the third embodiment, the culture vessel 102 has a removable lid 320. In some embodiments, the removable lid 320 need not be provided, and the inlet hole 116 can be arranged in the upper surface of the culture vessel 102 as in the first and second embodiments. The inlet hole 116 is arranged through the removable lid 320, but is otherwise similar to the inlet hole 116 of the first and second embodiments, and a gas-tight seal is formed around the tube 318 at the inlet hole 116. The removable lid 320 can readily be applied to the first and second embodiments.

[0265] The tube 318 is connected to the inlet pipe 112. In particular, an inlet end 322 of the tube 318 is connected to the open end 114 of the inlet pipe 112. In the third embodiment, the tube 318 fits over the inlet pipe 112 such that a substantially gas-tight seal is formed. The tube 318 is made from a flexible and deformable material such that it can form a friction fit over the inlet pipe 112 to form a seal.

[0266] In the third embodiment, the connection between the inlet pipe 112 and the tube 318 is arranged outside of the culture vessel 102. This facilitates easy connection and disconnection of the inlet pipe 112 and the tube 318. Furthermore, because the interior of the culture vessel 102 is often under sterile conditions, avoiding exposing the Sphagnum 106 to the external environment is desirable, so having the connection accessible without removing the lid 320 is desirable.

[0267] In the third embodiment, the tube 318 also has an outlet end 324 at the opposite end of the tube 318 to the inlet end 322. The tube 318 thus extends between the inlet end 322 and the outlet end 324. The outlet end 324 is arranged to extend through an outlet hole 326 in the culture vessel 102. The outlet hole 326 is also arranged in the removable lid 320 of the culture vessel 102. The outlet hole 326 may be similar to the inlet hole 116, and for example is gas-tight sealed around the tube 318.

[0268] The apparatus 300 also comprises an outlet pipe 328. The outlet pipe 328 is similar to the inlet tube 112 and is also impermeable to carbon dioxide. In the third embodiment, the outlet pipe 328 is made from nylon. The outlet pipe 328 has an open end 330 which is connected to the outlet end 324 of the tube 318. The tube 318 therefore forms a conduit between the inlet pipe 112 and the outlet pipe 328. In this way, the tube 318 provides a duct from the inlet hole 116 to the outlet hole 326 through the airspace 108 of the culture vessel 102. The duct is a closed loop section, with either end of the tube 318 passing through the removable lid 320.

[0269] The tube 318 is permeable to carbon dioxide. In the third embodiment, the tube 318 is made from silicone rubber. Carbon dioxide supplied from the source of carbon dioxide 110 can flow through the inlet pipe 112 and into the tube 318. The carbon dioxide can then diffuse through the wall of the silicone tube 318 and into the airspace 108. This diffusion is indicated by Arrow B in FIG. 3.

[0270] In the third embodiment, the tube 318 has a length of around 15 cm, with a length of the part of the tube 318 arranged in the airspace of around 10 cm. In the third embodiment, the inner diameter of the tube is 3 mm. In the third embodiment, the thickness of the tube is 1 mm.

[0271] As the tube 318 is also connected to the outlet pipe 328, carbon dioxide that does not diffuse through the permeable tube 318 will be output into the outlet pipe 328. After leaving the tube 318, the outlet pipe 328 can then channel the carbon dioxide where desired. For example, the outlet pipe 328 may be connected to a liquid reservoir where the carbon dioxide is bubbled out of the outlet pipe 328 and into the liquid. In other examples, as described below in relation to the fifth embodiment, the outlet pipe 328 may be connected to another culture vessel 502 to provide a continuous and serial supply of carbon dioxide to multiple culture vessels 102, 502 in a row.

[0272] In alternative embodiments, the apparatus 300 does not comprise an outlet pipe 328 and an outlet hole 326. Instead, the tube 318 is sealed at one end such that carbon dioxide is forced to diffuse through the permeable tube 318 into the airspace 108.

[0273] Referring to FIG. 4, according to a fourth embodiment of the disclosure, an apparatus 400 is provided. The apparatus 400 of the fourth embodiment may include one or more features described above in relation to any of the first to third embodiments. The same reference numerals are used to denote identical features.

[0274] In particular, the apparatus 400 of the fourth embodiment is similar to the apparatus 300 of the third embodiment shown in FIG. 3, except that the apparatus 400 further comprises a light source 432.

[0275] In the fourth embodiment, the light source 432 is a white fluorescent tube having a power of 36 W. In other embodiments, the light source 432 may comprise one or more light emitting diodes (LEDs).

[0276] The light source 432 is arranged at one side of the culture vessel 102. In particular, the light source 432 is only arranged at one side of the culture vessel 102, and there is no light source arranged on the opposite side. The light source 432 is arranged at a distance less than a width of the culture vessel 102 away from the side of the culture vessel 102.

[0277] The light source 432 provides light to the Sphagnum for growth by photosynthesis. The general direction of light emitted towards the culture vessel 102 is indicated by Arrows C. Although not shown, light is emitted in all directions around the longitudinal axis of the fluorescent tube of the light source 432.

[0278] The light source 432 is arranged to extend over a height equal to or greater than the height that the liquid medium 104 extends in the culture vessel 102. Thus, the light source 432 is arranged to supply light to Sphagnum 106 throughout the entire height of the liquid medium 104. In alternative embodiments, the light source 432 is arranged to extend over a height equal to or greater than the height of the culture vessel 102.

[0279] Efficient use of the light source 432 can be made by arranging a cluster of culture vessels 102 around the light source 432 as will be described below with respect to the sixth embodiment.

[0280] In the fourth embodiment, the light source 432 also acts as a heat source. Light source 432 inherently has inefficiencies in converting electrical power into light, resulting in waste heat. The light source 432 thereby heats up the near side of the culture vessel 102. Because the light source 432 is arranged towards one side, it heats up the near side of the culture vessel 102 more than the far side. This heating effect is sufficient to create a temperature differential across the culture vessel 102.

[0281] The temperature differential is significant enough to create convection currents in the liquid medium 104. Liquid towards the near side is heated more, and therefore rises towards the surface. Liquid at the top is displaced by more rising liquid, and is pushed away from the near side towards the far side. As it moves over the top surface away from the heat source, it cools and sinks back down to the bottom, and is further displaced by heated liquid. This is then, in turn, displaced by cooling liquid, and is pushed away from the far side towards the near side along the bottom surface. Thus, a convention current is generated generally as indicated by Arrows D.

[0282] The convection currents cause a stirring effect with the liquid medium 104 and increase the uptake of carbon dioxide from the airspace 108 into the liquid medium 104. By agitating fresh liquid medium 104 into contact with the airspace 108, saturation can be avoided and the efficiency of the uptake of carbon dioxide by the liquid medium 104 can be increased. By stirring the liquid medium 104 in this way, the diffusion gradient is kept high and the rate of diffusion can be improved. This means that the rate of supply of carbon dioxide to the liquid medium 104 containing the Sphagnum 106 can be increased.

[0283] Referring to FIG. 5, according to a fifth embodiment of the disclosure, an apparatus 500 is provided. The apparatus 500 of the fifth embodiment may include one or more features described above in relation to any of the first to fourth embodiments. The same reference numerals are used to denote identical features.

[0284] The apparatus 500 of the fifth embodiment comprises all of the features of the apparatus 400 of the fourth embodiment. In overview, the apparatus 500 comprises the apparatus 400 connected to a second apparatus having similar features.

[0285] In particular, the apparatus 500 comprises a second culture vessel 502 which is similar to the first culture vessel 102. The second culture vessel 502 contains a liquid medium 504 and Sphagnum 506 therein. The second culture vessel 502 contains an airspace 508 above the liquid medium 504.

[0286] The apparatus 500 also contains an inlet pipe 512 which has an open end 514. In the fifth embodiment, the inlet pipe 112 is the distal end of the outlet pipe 328 from the first culture vessel 102. In alternative embodiments, the inlet pipe 512 is a separate pipe which is connected to the outlet pipe 328.

[0287] In a corresponding manner to the first culture vessel 102, the second culture vessel 502 also comprises an inlet hole 516 and an outlet hole 526 in a lid 520. A tube 518 extends between the inlet hole 516 and the outlet hole 526 by attaching between the open end 514 of the inlet pipe 512 and the open end 530 of an outlet pipe 528. The tube 518 is permeable to carbon dioxide in the same way as the tube 318.

[0288] The first culture vessel 102 is therefore connected to the second culture vessel 502 by virtue of the outlet pipe 328 of the first culture vessel 102 connecting to the tube 518 of the second culture vessel 502. Therefore, carbon dioxide is supplied from the source of carbon dioxide 110 to the first culture vessel 102 and then successively to the second culture vessel 502. Carbon dioxide which does not diffuse out of the tube 318 into the airspace 108 in the first culture vessel 102 can then be supplied for diffusion into the second culture vessel 102 through the tube 518 into the airspace 508.

[0289] The apparatus 500 comprises a shared light source 532 arranged between the first culture vessel 102 and the second culture vessel 502. As the light source 532 is arranged closer to one side of each of the first culture vessel 102 and the second culture vessel 502, a convection current can be generated in each of the first culture vessel 102 and the second culture vessel 502, as described above.

[0290] In this way, carbon dioxide can be supplied to a plurality of culture vessels 102, 502 by connecting the culture vessels 102, 502 in sequence. Carbon dioxide is thus supplied in a continuous conduit via the inlet pipe 112 of the first culture vessel 102, the tube 318 of the first culture vessel 102, the outlet pipe 328 of the first culture vessel 102, the inlet pipe 512 of the second culture vessel 502, and the tube 518 of the second culture vessel 502. Therefore, because of the diffusion through the walls of the tubes 318, 518, carbon dioxide can be supplied by connections of pipes in series, rather than having a dedicated source of carbon dioxide 110 for each culture vessel 102, 502. This allows for easy scaling up of the number of culture vessels 102, 502, and for a modular design whereby more or fewer culture vessels 102, 502 can be added to the sequence.

[0291] In alternative embodiments, the outlet pipe 528 of the second culture vessel 502 is not closed at its end. Instead, the outlet pipe 528 is connected to an inlet pipe of a third culture vessel, to link to a further culture vessel and supply carbon dioxide in a corresponding manner.

[0292] Referring to FIG. 6, according to a sixth embodiment of the disclosure, an apparatus 600 is provided. The apparatus 600 of the sixth embodiment may include one or more features described above in relation to any of the first to fifth embodiments. The same reference numerals are used to denote identical features.

[0293] The apparatus 600 of the sixth embodiment comprises all of the features of the apparatus 500 of the fifth embodiment. In overview, the apparatus 600 comprises the apparatus 500 connected to a third apparatus and a fourth apparatus having similar features.

[0294] FIG. 6 shows the apparatus in a plan view from above. In particular, the apparatus 600 of the sixth embodiment comprises a first culture vessel 102 and a second culture vessel 502 similar to the fifth embodiment. The first culture vessel 102 is connected to the second culture vessel 502 in a similar manner to the fifth embodiment. In particular, the first culture vessel 102 has an inlet hole 116 and an outlet hole 326 in the upper surface. The first culture vessel 102 has a permeable tube 318 arranged between the inlet 116 and the outlet 326 and extending within the enclosed airspace of the culture vessel 102. The tube 318 is illustrated in phantom in FIG. 6 to demonstrate it is below the upper surface (e.g. the lid) of the culture vessel 102. The tube 318 is connected to an inlet pipe 112 at the inlet 116. The tube 318 is also connected to an outlet pipe 328 at the outlet 326. The outlet pipe 328 forms an inlet pipe to the second culture vessel 502. The outlet pipe 328 is connected to a permeable tube 518 at an inlet 516 of the second culture vessel 502. The tube 518 extends from the inlet 516 to an outlet 526, where it is connected to an outlet pipe 528.

[0295] The apparatus 600 also comprises a third culture vessel 602 and a fourth culture vessel 702. Each of the third culture vessel 102 and fourth culture vessel 102 is similar to the culture vessels 102, 502 of the fifth embodiment.

[0296] The second culture vessel 502 is connected to the third culture vessel 602 in a similar manner to the connection of the first culture vessel 102 to the second culture vessel 502. In particular, the outlet pipe 528 is connected to a permeable tube 618 of the third culture vessel 602 at an inlet 616. The tube 618 extends between the inlet 616 and an outlet 626. The tube 618 is connected to an outlet pipe 628 at the outlet 626.

[0297] The third culture vessel 602 is connected to the fourth culture vessel 702 in a similar manner to the connection of the first culture vessel 102 to the second culture vessel 502 and the connection of the second culture vessel 502 to the third culture vessel 602. In particular, the outlet pipe 628 is connected to a permeable tube 718 of the fourth culture vessel 702 at an inlet 716. The tube 718 extends between the inlet 716 and an outlet 726. The tube 718 is connected to an outlet pipe 728 at the outlet 726.

[0298] In the sixth embodiment, the culture vessels 102, 502, 602, 702 are arranged in contact with adjacent culture vessels 102, 502, 602, 702. In particular, the culture vessels 102, 502, 602, 702 are arranged in a loop or cluster so that the fourth culture vessel 702 is in contact with the third culture vessel 602 and the first culture vessel 102. In other embodiments, the culture vessels 102, 502, 602, 702 need not be in contact.

[0299] The apparatus 600 also includes a light source 632 arranged between the first culture vessel 102, the second culture vessel 502, the third culture vessel 602, and the fourth culture vessel 702. In other words, the culture vessels 102, 502, 602, 702 are clustered around the light source 632. The light source 632 is a fluorescent tube similar to the third to fifth embodiments, and is arranged vertically generally parallel to a height of the culture vessels 102, 502, 602, 702.

[0300] In this manner, space can be utilised whilst achieving the advantages described herein. Light is emitted out of the light source 632 in 360 as indicated by Arrows C. The plurality of culture vessels 102, 502, 602, 702 are arranged to surround the light source 632 to maximise use of the light.

[0301] In alternative embodiments, other numbers of culture vessels can be arranged around the light source 632. For example, more than four culture vessels 102, 502, 602, 702 can surround a single light source 632. In one example, six culture vessels can surround a light source 632.

[0302] In alternative embodiments, another cluster of culture vessels may additionally be provided. This cluster can be arranged around another light source. Because the culture vessels 102, 502, 602, 702 of the first cluster are separated from the light source surrounded by the second cluster, the light source of the second cluster has far less effect than the light source 632 of the first cluster. This ensures a temperature gradient is provided as desired. The first cluster may be connected to the second cluster to provide a supply of carbon dioxide.

[0303] In alternative embodiments, further culture vessels can be stacked on top of each other (e.g. providing eight culture vessels by stacking two layers of the cluster of four culture vessels). This can provide better use of space, especially where a fluorescent tube is used as the light source 632 and the tube is at least the height of two culture vessels. This provides light into the height of the liquid medium 104 in each culture vessel.

[0304] The arrangement of the sixth embodiment not only provides an optimum use of space and ensures an even use of light from the vertical tubes, but it also efficiently supplies carbon dioxide to a plurality of culture vessels 102, and also provides a heat source at one side of each culture vessel 102 in an effective manner to stir the liquid media 104.

[0305] In one example, 96 culture vessels each of 5 L volume are arranged on a Danish trolley, with 6 culture vessels clustered around each tube light source (with two light sources arranged through the two holes in the trolley shelves) to provide 12 culture vessels on each shelf, with each shelf having culture vessels stacked two high, and providing four shelves per trolley. Therefore 96 culture vessels can be cultured using two light tubes, and supply of carbon dioxide can be supplied by serially connected each culture vessel.

EXAMPLES

Example 1

[0306] Materials and Methods

[0307] A trial was set up to determine the effects of providing a light source as a heat source in order to generate a convection current for stirring a liquid culture medium for culturing Sphagnum. FIG. 7 shows the arrangement 700 of the experimental setup.

[0308] A light source 702 was provided in the form of a fluorescent tube. The fluorescent tube was a 36 W tube emitting white light. The light source 702 can be seen towards the left-hand side of FIG. 7.

[0309] A culture vessel in the form of a 5 L polypropylene container 704 was partially filled with water to represent a liquid culture medium. Sphagnum was omitted from the water to aid visual indication of currents. The container 704 was positioned adjacent to the light source 702. The rim of the lid of the container 704 was placed as close to the light source 702 as possible without touching. The container 704 was arranged so that the light source 702 was arranged at the near side 706, but there was no other light or heat source arranged adjacent the opposite far side 708 of the container 704.

[0310] The temperature was measured using a mercury thermometer 710 located at the bottom corner of the water at the near side 706 nearest the light source 702 and at the far side 708 furthest from the light source 702. A thermometer 710 was positioned at each location to provide constant readings to detect any variations.

[0311] Liquid ink was then administered to the water in the container 704 to act as a visual indicator to demonstrate any convection current. A narrow plastic tube was used to hold liquid ink via capillary action. The tube was then lowered into contact with the upper surface of the water, the suction force drawing the ink out in a consistent manner. Two drops were placed onto the surface at the same time: one towards the near side 706 nearest the light source 702, and one towards the far side 708 furthest from the light source 702.

[0312] Once the drops were administered, the motion of the drops was observed to indicate currents within the water.

[0313] Results

[0314] For the container 704 adjacent the light source 702, the temperature at the far side 708 (furthest from the light source 702) was measured to be 20 C. The temperature at the near side 706 (nearest the light source 702) was measured to be 23 C., and fluctuated between 22.5 C. and 23 C. throughout the experiment. This provided a temperature differential across the width of the container 704 of 2.5 C. to 3 C.

[0315] The drop in the container 704 at the near side 706 adjacent the light source 702 was observed to behave differently to the drop at the far side 708. In particular, the droplet at the near side 706 was slower to sink to the bottom than the droplet at the far side 708.

[0316] FIG. 8 shows a photograph of the arrangement 800 similar to the arrangement 700 of FIG. 7 after administering droplets of ink onto the water, the droplets of ink 812 and 814 visible in contrast to the colourless water. The light source 702 can be seen towards the right-hand side of FIG. 8. After a predetermined time period, the droplet of ink on the near side 706 had sunk less than at the far side 708. FIG. 8 shows a snapshot after the predetermined time period, and shows the droplet 812 at the near side 706 towards the light source 702 towards the right-hand side of FIG. 8, and the droplet 814 at the far side 708 towards the left-hand side of FIG. 8. As shown, the droplet 812 at the near side 706 was observed to sink less than the droplet 814 at the far side 708. This confirmed that a convection current was being generated within the water to cause an upward movement on the near side 706 due to heating by the light source 702 and a downward movement on the far side 708. Due to the heat from the light source 702, the near side 706 experiences a buoyancy effect due to the rising warmer liquid.

[0317] The droplet 814 at the far side 708 was then observed to diffuse along the bottom towards the near side 706, whereas the droplet 812 at the near side 706 began to diffuse upwards and eventually along the upper surface of the water towards the far side 708. The movement of the droplet 812 was observed to be slower than the droplet 814 because the convention current had to overcome the weight of the ink, which was heavier than the water.

[0318] FIGS. 9A to 9C show successive photographs in time from above of the arrangement 900 similar to the arrangement 800 of FIG. 8. The light source 702 is shown towards the top of FIGS. 9A to 9C, where the near side 706 of the container 704 is shown towards the top and the far side 708 is shown towards the bottom.

[0319] FIG. 9A shows a snapshot of the droplet 912 at the near side 706 and the droplet 914 at the far side 708 after a predetermined time period after dropping the droplets 912, 914 into the water. The droplet 912 can be seen at the upper surface of the water in the container 704, whereas the droplet 914 can be seen at the bottom surface of the container 704. The droplets 912, 914 are beginning to diffuse into a cloud of ink. The droplet 914 at the far side 708 can be seen to be present at a furthest point 916 towards the near side 706 around the position of the centre circle of the container 704.

[0320] FIG. 9B shows a snapshot a predetermined time period after the snapshot of FIG. 9A. The droplet 914 at the far side 708 can be seen to have moved relative to the snapshot of FIG. 9A. In particular, the droplet 914 has moved towards the near side 706, and can be seen to be present at a furthest point 916 which is beyond the centre circle of the container 704. The ink droplet 914 has moved in the direction from the far side 708 towards the near side 706 along the bottom surface of the container 704. The droplet 912 is also shown to have moved away slightly from the near side 706 towards the far side 708.

[0321] FIG. 9C shows a snapshot a predetermined time period after the snapshot of FIG. 9B. The droplet 914 at the far side 708 can be seen to have moved relative to the snapshot of FIG. 9B. In particular, the droplet 914 has moved towards the near side 706, and can be seen to be present at a furthest point 916 which is well beyond the centre circle of the container 704. The ink droplet 914 has moved in the direction from the far side 708 towards the near side 706 along the bottom surface of the container 704. The droplet 912 is also shown to have moved further away from the near side 706 towards the far side 708.

[0322] The droplet 914 diffused along the bottom surface of the container 704. As it reached the near side 702, it began to rise towards the upper surface. This clearly demonstrates the convention current which stirs the water due to the temperature differential applied by the light source 702 at the near side 706.

Example 2

[0323] Material and Methods

[0324] A trial was conducted using an apparatus similar to that described above in relation to FIG. 4. Sphagnum was placed into a liquid culture medium within a 2 L culture vessel. The liquid culture medium comprised nutrients comprising 48.23 mg per L of nitrogen, 9.67 mg per L of phosphorus, 123.46 mg per L of potassium, 32.63 mg per L of calcium, 9.12 mg per L of magnesium, 1.32 mg per L of sodium, 5.49 mg per L of manganese, 0.02 mg per L of copper, 1.96 mg per L of zinc, 62.55 mg per L of sulfur, 1.08 mg per L of boron, 1.40 mg per L of iron, mg per L of molybdenum, 11.69 mg per L of chlorine, 0.006 mg per L of cobalt, and 0.63 mg per L of iodine. There was no sugar in the culture medium.

[0325] A permeable tube made from silicone rubber was inserted through a lid of the culture vessel. The permeable tube had a length of around 15 cm, with 10 cm within the interior of the culture vessel. The tube had an inner diameter of 3 mm and a wall thickness of 1 mm. The tube was formed into a loop, threaded into and out through the lid of the culture vessel. One end of the tube was connected to a nylon inlet pipe which was in turn connected to a source of carbon dioxide in the form of a canister of carbon dioxide (at least 99% pure), commercially available from BOC, UK. The other end of the tube was connected to a nylon outlet pipe, with the distal end of the outlet pipe placed into a jar of water to bubble through as an outlet. The carbon dioxide provided a source of carbon for photosynthesis by diffusion through the permeable tube into the airspace as described above.

[0326] The culture vessel was stored in a temperature-controlled growth room, with the temperature controlled to around 23 C. The culture vessel was illuminated with a light source in the form of a white fluorescent tube of 36 W providing a light intensity of 100 mol m.sup.2 s.sup.1 PAR. The light source provided a heat source to stir the liquid medium as described above.

[0327] FIG. 10 shows the apparatus 1000 used for the trial. The apparatus 1000 shows the culture vessel 1002 with Sphagnum 1006 arranged within the liquid medium 1004.

[0328] The Sphagnum was cultured in the culture vessel 1002 for 12 weeks.

[0329] Results

[0330] FIG. 11 shows the apparatus 1100 which corresponds to the apparatus 1000 of FIG. 10 after 12 weeks of culturing. The apparatus 1100 of FIG. 11 shows the culture vessel 1002 containing the liquid medium 1004. The Sphagnum 1106 has undergone significant growth compared to the Sphagnum 1006 of FIG. 11. After the 12 weeks of growth, around four times increase in growth of the Sphagnum was achieved.