Lighting System

All lighting in miniBIOTA is external to the glass habitat.

All lighting in miniBIOTA is external to the glass habitat. The design constraint that no electronics or active devices enter the glass habitat (established for the Wave and Tide System and the atmospheric heat exchangers) applies equally here: light sources, drivers, controllers, and hardware are outside the biosphere, and light enters through the glass. This protects organisms from electrical hazards, from heat produced by fixtures at close range, and from any mechanical disturbance associated with lighting hardware. Installed hardware as Hardware currently records it. Each of the six biomes has its own light, switched by one smart outlet on one of two TESSAN WiFi smart power strips (Freshwater Lake, Lakeshore, and Prairie on one strip; Mangrove Forest, Marine Shore, and Seagrass Meadow on the other). The outlets are either fully on or fully off. The existing lights hang from a circular support structure that Josue identifies as a maintenance problem, and the build roadmap notes that the current lights sit too close to the top of the biome covers. Fixture models, wattage, spectrum, and supply voltage of the installed lights are not documented. The ecological implications of the Lighting System extend across every biome: In the Seagrass Meadow, PAR determines seagrass productivity and its competitive position against macroalgae and cyanobacteria-like surface growth. Shoal grass, turtle grass, and manatee grass all require sustained PAR delivery to the substrate. Graceful Redweed and Fern Alga can exploit light more opportunistically. PAR level is one of the variables that tips the producer competition outcome between seagrasses and macroalgae. In the Freshwater Lake, PAR drives duckweed surface growth and supports the tapegrass macrophyte layer, which provides structure for amphipods, Ghost Shrimp, snails, and small crustaceans at depth. Water clarity and PAR penetration are directly linked in this biome. In the Prairie, PAR sustains the grass community (Bermuda grass, St. Augustine, other introduced grasses), Mexican primrose, creeping beggarweed, and broadleaf forbs. Without adequate PAR, plant biomass declines, which removes the substrate and food source for grasshoppers, crickets, and the detritivore community below. In the Mangrove Forest, light penetrating the mangrove canopy regulates understory conditions. The dense canopy creates lower-light, sheltered conditions that favor moisture-adapted organisms over open-habitat species. In the Marine Shore and Lakeshore, edge-biome light conditions support biofilm, surface algae, and grazing organisms (Eastern Melampus, Amber Snail) that use the wet glass and substrate surfaces as foraging habitat. Because fixture, spectrum, and PAR remain undocumented, Research cannot make specific PAR claims for any biome. Stronger claims about producer growth rates, competitive outcomes between seagrass and macroalgae, or photosynthetic capacity across any biome are all constrained by this documentation gap. Photoperiod itself is confirmed: a fixed 12/12 schedule with instant transitions, not the variable seasonal photoperiod Florida's natural systems experience (roughly 10 hours in December to 14 in June). miniBIOTA's organisms currently receive a constant year-round day length, which decouples any photoperiod-driven seasonal cue from natural Florida timing. The planned rebuild aims at software-controlled dimming, ramping, and color change, and the build roadmap describes a programmable seasonal arc as the expected outcome; none of that exists yet. Lighting history. The build log carries three retrospective entries, reconstructed in 2026 from photo-catalog interviews rather than logged at the time, describing lighting on the prototypes that came before the current six-biome assembly. In December 2019 Josue built a ten-socket spotlight canopy for the original 29-gallon terrarium, which was running under a magenta/purple grow-light spectrum by the end of that month. In January 2020 he compared LED color temperatures over the prototype freshwater tank and judged all the artificial spectra he tried unnatural. In August 2020 the prototype lab arrays used MR16 GU10 LED bulbs, rated as 50-watt-halogen equivalents and chosen for high output; those bulbs were later phased out specifically to keep 120 V household power away from the water-filled tanks. Whether that "no mains voltage near water" rule becomes a written constraint for the rebuild is an open question for Josue; Hardware has flagged it but not decided it. The planned rebuild. The rebuild is a full from-scratch build (new lens, LED module, heat sinks, and controllers), not a modification of the current fixtures. Funding is the named gate, the bill of materials is not worked out, and Josue is deliberately sequencing it after other systems. His September 4, 2026 plan is to finish the climate, atmosphere, rain, and cloud work through Fall 2026 and move on to lighting in Winter 2026-27. Winter 2026-27 vision (owner direction, September 16 to 19, 2026). The concept is a custom light that moves along a rail and rotates so its beam follows a simulated sun path across a 29-gallon test tank: low-angle and dimmer at one edge in the morning, pointing straight down and brightest at midday, low and dimmer at the opposite edge in the evening. The intended color range is tunable white from about 2700 K to 6500 K, with optional separate RGB emitters for sunrise and sunset accents. A full build might use six white lights in three front-and-back pairs, but that count is a concept only and depends on the optics evaluation. Josue's stated development order is optics first (LED, lens, heat sink), then electrical and thermal feasibility, then mount and motion design. The stated motivation is to reduce persistent plant burn spots beneath the stationary lights; the build records treat this as an untested motivation, and the cause of the burn spots is not established. Fall 2026 optical trial (planning only). The first trial is one point light tried with different beam angles, to learn what works before committing to a light count. Josue classified it as a supporting Fall item on September 19, 2026; it blocks nothing in the Fall climate sequence. Hardware has worked out the coverage geometry for a bare emitter and for lensed beams, but nothing has been purchased, built, or tested, no lens is selected, and no tank or plant measurement exists. Josue and Research have not yet defined what "covered" means. LED module and supply voltage. Josue looked at one candidate LED, the Cree XLamp CTW09 family (a two-channel tunable-white chip-on-board LED), and supplied its datasheet on September 19, 2026. It is a candidate only, not selected or bought. It needs roughly 36 V per channel, and later that day Josue found the National Electrical Code Article 411 limit for low-voltage lighting where wet contact is likely (30 V DC). His first working conclusion was that 36 V class lighting near the biomes was out. Josue's stated preference (October 15, 2026) is to stay under 30 V for lighting, with 36 V acceptable if it proves the best option. The supply voltage remains open. Optional Fall serviceability retrofit (exploratory, September 9, 2026). Separately from the rebuild, Josue wants to investigate a 3D-printed replacement for the current circular support that keeps the existing lights but makes them easier to reach and service, using the access already planned when atmosphere hardware is detached in Fall. Geometry, materials, heat behavior, which biomes are included, and acceptance criteria are all open. It changes no light, spectrum, intensity, or photoperiod, and neither effort gates the other. On September 21, 2026 Josue named the factors that would make a prototype worth developing into the full Winter array: fair cost, the right intensity and tunable spectrum, proper ground coverage, staying cool in continuous operation, and a clean look. These are open criteria, not validated specifications. Old lamp components rejected (October 11, 2026). Josue took apart a tunable-white plus RGB lamp (120 V AC, 5 W) to judge whether its mains supply could be removed so it would run on 12 or 24 V in the biomes, and decided against it: the fixture will be custom built, not assembled from old components. This does not affect the serviceability retrofit, which keeps the current lights in a new support. Lighting power and wiring (direction, September 24, 2026). Josue opened a Fall-or-Winter design direction to gather the light power supplies into a suitable enclosure, run conduit-protected wiring to junction boxes at the top of each biome, protect floor runs, and remove visible wiring from the visitor experience. The supplies, timer, mains and low-voltage boundary, and routing still need engineering and code review; nothing has been designed or built.

Seagrass producer competition: The three-way competition between seagrasses (shoal grass, turtle grass, manatee grass), macroalgae (Graceful Redweed, Fern Alga, Giant Feather Alga), and cyanobacteria-like surface growth is partly a competition for PAR. Macroalgae and surface growth forms can exploit light more opportunistically than seagrasses in some conditions, particularly at the substrate surface where seagrasses must root and establish. Without PAR measurements at the Seagrass Meadow substrate level, the role of lighting versus grazing pressure (Mud Crab, Variegated Sea Urchin, and formerly the Eelgrass Isopod and hard-surface snails) versus substrate disturbance in determining producer competition outcomes cannot be separated. Common Atlantic Marginella, previously listed here among the grazers, was a predator and sediment bioturbator rather than an algal grazer; corrected July 29, 2026.

Photoperiod controls a producer's vertical position: Documented July 29, 2026, the Graceful Redweed floating mat in the Seagrass Meadow runs a daily vertical cycle tied directly to the lighting schedule. Photosynthetic oxygen bubbles accumulate within and beneath the mat through the photoperiod and lift it to the surface, with lift beginning after the lights come on; overnight, with production stopped, hermit crab weight and wave action press it back toward mid-column or the substrate. The lighting photoperiod therefore determines where this producer sits in the light layer on a daily basis, and by extension what it shades beneath it. No lighting change has been made in response, and the effect was observed rather than engineered.

Burn spots and the moving-light concept: The Winter vision is motivated by persistent plant burn spots beneath the stationary lights, and the current lights sit close to the tops of the biome covers. Neither the cause of the burn spots nor any link to fixture height, intensity, or spectrum is established, and a moving light has not been shown to remove them. The optical trial could be designed to compare steady and moving exposure, but no such test exists. Until then, burn spots are a reported plant condition with an untested hardware hypothesis attached, not a confirmed lighting effect.

Electrical safety near water: The lights sit above humid, splash-prone biomes. Mains-voltage bulbs were phased out of the 2020 prototypes for that reason, Josue prefers to stay under the 30 V wet-contact limit from NEC Article 411 but would accept 36 V if it is the best option, and the planned power-supply consolidation still needs engineering and code review. The rebuild's supply voltage and the place where mains power stops are unresolved, so the rebuild's electrical design cannot be described as settled.

Documentation gap and public claims: Without documented PAR or spectrum, Research cannot make specific photosynthesis or growth-rate claims in any public-facing context. This is the most consequential documentation gap across all six hardware systems. The absence of PAR data is not a minor gap; it affects the credibility of ecological claims in the Seagrass Meadow, Freshwater Lake, and Prairie simultaneously. The rebuild planning has so far produced coverage geometry for a candidate emitter, not any measurement inside a biome.

Enclosure glass as a light filter: The glass walls and top surfaces of the biome tanks filter some portion of the light entering from outside. The spectral transmission of aquarium glass is not flat; UV is attenuated and some visible wavelengths are absorbed. Without measurements, the relationship between the fixture output outside the glass and the PAR delivered inside the biome is unknown. The trial plan adds that refraction narrows a beam once it enters water and that glass, surface disturbance, and canopy shading are all unquantified.