Mars Regolith Cyanobacteria/Microalga Biofertilizer Panel

The organisms were assayed separately, not as a coculture. COMMUNITY_LEVEL is retained as the current container for shared abiotic/panel observations, not evidence of emergent community activity; record-model placement remains OPEN under #573. Autoclaved MGS-1 aqueous extract contained measured S, K and Ca and smaller amounts of other elements (main Table 1). Element totals do not establish ionic speciation, bioavailable uptake or a complete growth medium. Phosphorus was not detected in the extract, and 5 mL of established inoculum was added to 75 mL treatment, so intracellular reserves and medium carryover cannot be excluded. Cultivation used an Earth-like atmosphere, not exposed Martian surface conditions.

Participating Taxa: Anabaena cylindrica, Nostoc muscorum, Arthrospira platensis, Chlorella vulgaris

Metabolites: water (CHEBI:15377 · MediaIngredientMech · CMMMech), potassium(1+) (CHEBI:29103 · MediaIngredientMech · CMMMech), calcium(2+) (CHEBI:29108 · MediaIngredientMech · CMMMech)

Evidence

• PMID:35865930 - SUPPORT (IN_VITRO)
  "Mars regolith extract was rich in S, K, and Ca and contained smaller concentrations of Mn, Fe, and Sr, and trace concentrations of Cu, Zn, Br, and Rb"

The organisms were assayed separately, not as a coculture. COMMUNITY_LEVEL is retained as the current container for shared abiotic/panel observations, not evidence of emergent community activity; record-model placement remains OPEN under #573. Over 25 days, OD440 and photosystem-II fluorescence supported stronger growth of Nostoc muscorum and Anabaena cylindrica in regolith extract than Arthrospira platensis or Chlorella vulgaris. Nostoc was most consistent; Anabaena fluorescence declined after day 15 and biomass browned later. Arthrospira had mild visible growth and clumping that limited optical measurements, so categorical absence of viable growth is too strong. Photosynthetic efficiency is not measured oxygen production. Diazotrophy is an author-proposed explanation, not directly measured N2 fixation or an interaction among the four organisms.

Participating Taxa: Anabaena cylindrica, Nostoc muscorum, Arthrospira platensis, Chlorella vulgaris

Biological Processes:

• photosynthesis (GO:0015979 · PathwayMech)
• growth (GO:0040007 · PathwayMech)

Evidence

• PMID:35865930 - PARTIAL (IN_VITRO)
  "N. muscorum showed the best growth performance when compared to the other species, while A. platensis and C. vulgaris were not able to thrive on Mars regolith extract."
• PMID:35865930 - PARTIAL (IN_VITRO)
  "C. vulgaris was unable to grow, while N. muscorum and A. cylindrica thrived in Mars regolith extract."

Separate 25-day regolith-extract cultures were filtered through 0.45-um membranes or sonicated and supplied as media for a seven-day Lemna minor assay. Arthrospira filtrate and sonicate, and Chlorella filtrate, supported dry-weight yields not significantly different from Steinberg medium, while frond yields remained lower. Filtered versus sonicated treatments of the same species did not significantly differ. These positive processed-material effects are not live commensalism or statistical proof of equivalence. The better-growing Nostoc cultures gave the lowest Lemna yield, so phototroph growth advantage does not establish biofertilizer advantage. Nutrient profiles suggest possible mediation, but carryover, released contents and other metabolites were not selectively isolated. Lemna is the external recipient, not part of the four-phototroph inoculum roster.

Participating Taxa: Anabaena cylindrica, Nostoc muscorum, Arthrospira platensis, Chlorella vulgaris

Metabolites: nitrate (CHEBI:17632 · MediaIngredientMech · CMMMech), phosphate (CHEBI:18367 · MediaIngredientMech · CMMMech)

Biological Processes:

• growth (GO:0040007 · PathwayMech)

Evidence

• PMID:35865930 - PARTIAL (IN_VITRO)
  "Cyanobacteria and microalgae (A. platensis and C. vulgaris) showed good abilities as biofertilizing agents, i.e., they stimulated biomass (i.e., dry weight) production at levels comparable to the plants that grew on standard synthetic medium."