RESUMEN
The increase in hypoxia events, a result of climate change in coastal and fjord ecosystems, impacts the health and survival of mussels. These organisms deploy physiological and molecular responses as an adaptive mechanism to maintain cellular homeostasis under environmental stress. However, the specific effects of hypoxia on mussels of socioeconomic interest, such as Mytilus chilensis, are unknown. Using RNA-seq, we investigated the transcriptomic profiles of the gills, digestive gland, and adductor muscle of M. chilensis under hypoxia (10 days at 2 mg L-1) and reoxygenation (10 days at 6 mg L-1). There were 15,056 differentially expressed transcripts identified in gills, 11,864 in the digestive gland, and 9862 in the adductor muscle. The response varied among tissues, showing chromosomal changes in Chr1, Chr9, and Chr10 during hypoxia. Hypoxia regulated signaling genes in the Toll-like, mTOR, citrate cycle, and apoptosis pathways in gills, indicating metabolic and immunological alterations. These changes suggest that hypoxia induced a metabolic shift in mussels, reducing reliance on aerobic respiration and increasing reliance on anaerobic metabolism. Furthermore, hypoxia appeared to suppress the immune response, potentially increasing disease susceptibility, with negative implications for the mussel culture industry and natural bed populations. This study provides pivotal insights into metabolic and immunological adaptations to hypoxia in M. chilensis, offering candidate genes for adaptive traits.
Asunto(s)
Estrés del Retículo Endoplásmico , Branquias , Mytilus , Transcriptoma , Animales , Mytilus/genética , Branquias/metabolismo , Estrés del Retículo Endoplásmico/genética , Hipoxia/genética , Hipoxia/metabolismoRESUMEN
Seaweed aquaculture has become a profitable and an attractive alternative of cultivation thanks to its quick biomass production for food, feed, and other non-food applications. In addition, the ecosystem services generated by seaweed cultivation towards carbon fixation represents a more sustainable solution to the ocean's acidification. The growth of elkhorn sea moss (Kappaphycus alvarezii) was evaluated in three plots with 200 propagules during a period of 70 days in a floating raft system covered by a fishing net underneath. Initial weight of propagules was 159.3 ± 12.74 g in wet biomass and 15.3 ± 1.43 g in dry biomass and were sampled up to 19 days (in the lag growth phase; period I), up to 33 days (in the exponential growth phase; period II) and up to 70 days (in the stationarity growth phase; period III). The variations of sea surface water temperature, salinity, turbidity (Secchi depth), total ammonium, nitrites, nitrates, and phosphate were determined. The growth increase was more evident in the exponential phase II when a dry biomass of 28.0 ± 2.48 (1153.3 ± 6.25 g in wet mass) was reached, more than 7 times the biomass of propagules with an average daily growth rate of 15.2% g.day-1. The carrying capacity of the zone was estimated at 86.2% in the area where 53 cultivation units would be projected. The economic analysis presented a financial feasibility with a net profit of 19% over the projected income and an IRR of 16.5%, recovering the investment in an estimated period of 4.3 years. We recommend to continue with larger-scale studies to optimize the cultivation of K. alvarezii in the study area.