Copepods play a critical role in aquatic food chains and are a key source of food in aquaculture, so optimizing their culture conditions is essential for their large-scale production. The objective of this study was to determine the optimal culture parameters of the copepod Oithona nana as a function of total population growth and the different stages of its life cycle. To this end, four experiments were carried out in quadruplicate, evaluating the effects of temperature, salinity, photoperiod and optimal microalgal concentration of Isochrysis galbana. Each experiment lasted 15 days. Temperatures of 20, 24, 28 and 32 °C were tested; salinity levels of 20, 25, 30 and 35 PSU; photoperiods of 12L:12D, 16L:8D and 24L:0D; and concentrations of I. galbana of 1 × 10⁴, 5 × 10⁴, 10 × 10⁴, 15 × 10⁴ and 20 × 10⁴ cells/mL. Results indicated that the optimal temperature for the culture of O. nana, with significant differences compared to the other treatments, was 28 ± 1 °C. Regarding salinity, the optimal level for the total development of the population was 25 ± 2 PSU, while to maximize the percentage of copepodites, the most appropriate levels were 30 and 35 PSU. The light-dark regimen of 16L:8D promoted the highest total density of individuals, while 12L:12D and 16L:8D favored development of nauplii and copepodites. Finally, optimal concentrations of I. galbana that generated the highest densities of O. nana at all stages of its life cycle were 15 × 10⁴ and 20 × 10⁴ cells/mL. These findings provide key information for the development of optimized cultures of O. nana, which can improve its availability as a food source in aquaculture systems and favor the success of larval cultures in species of commercial interest.

Evidence combining energy management and life cycle assessment of diesel-to-CNG substitution under real fleet operation remains limited. The energy and environmental assessments were jointly applied over a common functional unit—the transport of 30 m³ of non-hazardous wastewater per documented service—with an annual reference flow of 82,422 m³·km derived from 38 services (1140 m³; 5905.2 km) in Lima, Peru. A single primary dataset fed both the energy baseline (characteristic monthly consumption of 22,828 ± 1435 MJ month⁻¹; service-level intensities of $2.209\pm 0.257$ vs. $1.237\pm 0.141$ MJ (m³·km)⁻¹, $n=38$, $p<0.001$) and the life cycle inventory, assessed in SimaPro v9.6.0.1 (ReCiPe 2016 Midpoint (H)) under an extended tank-to-wheel boundary with Pedigree–Monte Carlo uncertainty propagation. The transition—fuel substitution combined with Euro V-to-Euro VI platform renewal—reduced energy intensity by 45.3% and direct-combustion GWP₁₀₀ by 61.1%; this integrated effect is not attributable to the fuel change alone. Methane slip contributed 1.3% of the CNG GWP₁₀₀, and only an upstream leakage of 15.5% of the delivered gas would cancel the climate benefit. Tire replacement remained the dominant hotspot (64.5%/51.7%); immediate 30-vehicle fleet conversion would avoid 2530 t CO₂-eq over ten years.