TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Method: In culturing algae, the bioreactor comprises 2 tubes, each tube operably coupled to a different roller. The tubes comprise a thermal barrier. The method further comprises diverting medium above or below the thermal barrier to regulate the temperature of the medium. It also comprises separating algae from the medium, by removing oil from the algae. The method also comprises producing biodiesel from the oil, where the biodiesel is produced by transesterification. The method further comprises using axial vortex inducers to induce formation of rotating water columns within the tubes, the rotation of the water columns moving algae between the light-exposed upper region and the darker lower regions of the tube. The adjacent water columns in the tube rotate in opposite clockwise or counterclockwise directions. The method further comprises introducing CO2 gas into the medium using one or more CO2 bubblers. Algae are partially separated from the medium using a whirlpool device. It further comprises separating non-oil products from the algae, where the non-oil products comprise carbohydrates. The carbohydrates are converted into hydrogen gas, methane gas, and/or ethanol. The method further comprises harvesting the algae for use in animal or human food. Preferably, the algae are Spirulina, Dunaliella, or Tetraselmis. It further comprises using the algae as food for an algae-eating aquatic species, where the aquatic species is a peneid shrimp. In the method above, the tubes are arranged in a horizontal position on the ground. The method further comprises adjusting the height of the thermal barrier above the ground to control the temperature of the aqueous suspension. During daylight hours the flow of the aqueous suspension is directed below the thermal barrier to maintain the temperature of the suspension at ground temperature and above the thermal barrier to warm the suspension. During nighttime hours the flow of the aqueous suspension is directed above the thermal barrier to cool the suspension and below the thermal barrier to maintain the temperature of the suspension at ground temperature. The rollers reverse direction when they reach the ends of the tubes. Dip and belly pans are located below the roller at each end of each tube to allow medium to flow under the roller. The method further comprises controlling the movement of the rollers to prevent skewing. Preferred System: In the system above, the rollers are arranged to roll down the length of the flexible tubes to move the suspension through the tubes. The mechanism for harvesting algae comprises a whirlpool device and one or more sipper tubes. The whirlpool device comprises a speed-up ramp, a dwell tube, and a slowdown ramp. The rollers reverse direction at the ends of the tubes, where the positions of the speed-up and slowdown ramps are reversed when the rollers reverse direction. The mechanism for harvesting algae comprises at least one centrifuge. The apparatus for converting oil into biodiesel utilizes a transesterification process. In the system above, the rollers in contact with the tubes are arranged so that they compress the tubes to 85% of the height of the uncompressed tubes. Movement of the aqueous suspension through the tubes results in the formation of a fluid vortex within the whirlpool device. The whirlpool fluid movement results in a partial separation of oil-containing algae from the aqueous medium. The tubes contain a thermal barrier arranged horizontally within the tubes, to regulate the temperature of the aqueous suspension within the tubes. The thermal barrier comprises a 0.5-1.0 inch thick layer of polyethylene foam or other plastic containing an air filled cell construction. The upper surface of the thermal barrier comprises a layer of sand, a translucent ceramic or plastic, a silicate, or glass. It also exhibits an infrared emissivity of close to 1.0. Movement of the rollers along the tubes collects oxygen and other gases from the medium for removal from the system. The upper layer of plastic is indented with a linear Frenel pattern that collects sunlight from a lower Snell's law angle and directs it into the algae growing medium. The tubes are laid out perpendicular to the low angle southern sun for the winter months in temperate climates.    TECHNOLOGY FOCUS - POLYMERS - Preferred Polymer: The outer surface of the tubes is comprised of a plastic selected from polyethylene, polypropylene, polyurethane, polycarbonate, polyvinylpyrrolidone, polyvinylchloride, polystyrene, poly(ethylene terephthalate), poly(ethylene naphthalate), poly(1,4-cyclohexane dimethylene terephthalate), polyolefin, polybutylene, polyacrylate, or polyvinlyidene chloride. The outer surface of the tubes is comprised of 0.01 inch thick polyethylene.