Percorrer por autor "Costa, Monya"
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- Bioremediation of drainwater from soilless cultivation by Tetradesmus obliquus and Raphidonema monicae: growth performance and biochemical composition from lab to industrial scalePublication . Maia, Inês Beatriz; Pinto, Bruno; Carneiro, Mariana; Konucu, Merve; Schulze, Peter S.C.; Santos, Tamara; Rodrigues, Alexandre M.C.; Esteves Lopes Navalho, João Carlos; Costa, Monya; Pereira, Hugo; Varela, JoãoTo meet the demands of the growing population, agricultural practices have been increasing and putting a strain on land and freshwater usage. Soilless agriculture has emerged as a more sustainable practice to mitigate this issue but still generates nutrient-rich drainwater that can harm the environment if not properly managed. In this context, this study explores a circular economy approach to reuse the drainwater of soilless farming as a culture medium for microalgae production. For this, the growth performance of four strains, Chlorella sp., Nannochloropsis limnetica, Raphidonema monicae and Tetradesmus obliquus, was assessed using drainwater under summer and winter conditions at lab-scale. Based on productivity, protein and polyunsaturated fatty acids (PUFA) contents, T. obliquus and R. monicae were selected for comparison in pilot-scale flat-panel photobioreactors (FP-PBR) and raceway ponds (RW). T. obliquus presented significantly higher growth in FP-PBR (0.11 g L-1 d(-1)) compared to RW (0.09 g L-1 d(-1)), with complete nitrate removal in both systems. R. monicae showed similar growth across systems, removing 19 % of nitrate in FP-PBR and 56 % in RW. Principal component analysis indicated species-specific traits drive biochemical profiles, with limited influence from the cultivation system. Both species were cultivated in 19-m(3) tubular photobioreactors, with improved productivities (T. obliquus with 0.23 g L-1 d(-1) and R. monicae with 0.13 g L-1 d(-1)) until stationary phase or legal nitrate limits, yielding about 20 kg of dry weight each. The biomass produced in drainwater was biochemically characterized, showing it was rich in proteins (>30 %), PUFA (>55 %) and phenolics, highlighting their potential application in various sectors, including aquaculture and agriculture. Overall, this study demonstrates the potential of these strains for drainwater treatment, promoting a circular economy by converting waste into valuable biomass.
- Compared photophysiology of native seagrasses with an invasive macroalga in Sydney Harbour, AustraliaPublication . Silva, João; Runcie, J. W.; Barrote, Isabel; Costa, Monya; Santos, RuiThe comparative photophysiology of the seagrasses Zostera capricorni and Halophila ovalis and the invasive macroalgae Caulerpa taxifolia was investigated in a shallow mixed meadow at Chowder Bay (Sydney, Australia), where the three species coexist. This study was developed under the auspices of the COST Action “Seagrasses: from genes to ecosystems”, targeting one of its objectives, the development of innovative devices for the continuous measurement of seagrass photosynthesis. Automated multi-channel chlorophyll fluorometers were deployed for 24-hour periods to examine and compare the changes in the photosynthetic efficiency and energy quenching mechanisms of the 3 species. Tissue samples were collected at predawn and noon, frozen and analysed by HPLC for detailed pigment analysis. The invasive C. taxifolia showed generally higher photosynthetic efficiency than both Z. capricorni and H. ovalis. Both seagrass species showed down-regulation of photosynthesis at noon, evidenced by the low quantum yield and the significant reduction of the antennae pigments between pre-dawn and noon. In contrast, C. taxifolia showed no reduction in antennae pigments or total photosynthetic pigments along the day. While both seagrasses showed 3- to 7-fold increases in the epoxidation state of xanthophyll cycle pigments between pre-dawn and noon, in C. taxifolia there was no significant change. Our results show that C. taxifolia is better adapted to high light conditions than Z. capricorni and H. ovalis, which means that, from the photophysiological point of view, this invasive macroalgae constitutes a serious competitor for seagrasses in shallow areas with high irradiance.
- Comparison of different pretreatment processes envisaging the potential use of food waste as microalgae substratePublication . Marques, Fabiana; Pereira, Francisco; Machado, Luís; Martins, Joana T.; Pereira, Ricardo N.; Costa, Monya; Genisheva, Zlatina; Pereira, Hugo; Vicente, António A.; Teixeira, José A.; Geada, PedroA significant fraction of the food produced worldwide is currently lost or wasted throughout the supply chain, squandering natural and economic resources. Food waste valorization will be an important necessity in the coming years. This work investigates the ability of food waste to serve as a viable nutritional substrate for the heterotrophic growth of Chlorella vulgaris. The impact of different pretreatments on the elemental composition and microbial contamination of seven retail food waste mixtures was evaluated. Among the pretreatment methods applied to the food waste formulations, autoclaving was able to eliminate all microbial contamination and increase the availability of reducing sugars by 30%. Ohmic heating was also able to eliminate most of the contaminations in the food wastes in shorter time periods than autoclave. However, it has reduced the availability of reducing sugars, making it less preferable for microalgae heterotrophic cultivation. The direct utilization of food waste containing essential nutrients from fruits, vegetables, dairy and bakery products, and meat on the heterotrophic growth of microalgae allowed a biomass concentration of 2.2 x 108 cells center dot mL-1, being the culture able to consume more than 42% of the reducing sugars present in the substrate, thus demonstrating the economic and environmental potential of these wastes.
- Daily regulation of key metabolic pathways in two seagrasses under natural light conditionsPublication . Ruocco, Miriam; Barrote, Isabel; Hofman, Jan Dirk; Pes, Katia; Costa, Monya; Procaccini, Gabriele; Silva, João; Dattolo, EmanuelaThe circadian clock is an endogenous time-keeping mechanism that enables organisms to adapt to external environmental cycles. It produces rhythms of plant metabolism and physiology, and interacts with signaling pathways controlling daily and seasonal environmental responses through gene expression regulation. Downstream metabolic outputs, such as photosynthesis and sugar metabolism, besides being affected by the clock, can also contribute to the circadian timing itself. In marine plants, studies of circadian rhythms are still way behind in respect to terrestrial species, which strongly limits the understanding of how they coordinate their physiology and energetic metabolism with environmental signals at sea. Here, we provided a first description of daily timing of key core clock components and clock output pathways in two seagrass species, Cymodocea nodosa and Zostera marina (order Alismatales), cooccurring at the same geographic location, thus exposed to identical natural variations in photoperiod. Large differences were observed between species in the daily timing of accumulation of transcripts related to key metabolic pathways, such as photosynthesis and sucrose synthesis/transport, highlighting the importance of intrinsic biological, and likely ecological attributes of the species in determining the periodicity of functions. The two species exhibited a differential sensitivity to light-to-dark and dark-to-light transition times and could adopt different growth timing based on a differential strategy of resource allocation and mobilization throughout the day, possibly coordinated by the circadian clock. This behavior could potentially derive from divergent evolutionary adaptations of the species to their bio-geographical range of distributions.
- Effects of in situ shading on the photophysiology of Zostera marina and Cymodocea nodosaPublication . Silva, João; Barrote, Isabel; Albano, Sílvia; Costa, Monya; Neves, Pedro; Graça, Gonçalo Nuno Santos Neto da; Sharon, Yoni; Beer, S.; Santos, RuiThe effects of light reduction were investigated in natural stands of the seagrasses Zostera marina and Cymodocea nodosa in Ria Formosa coastal lagoon, southern Portugal. Four shading plots and a control were set in each of two neighbouring meadows (2-3 m depth), each dominated by one species. The experiment lasted for 3 weeks, at the end of which the response of plant photosynthesis to light was determined via oxygen electrode measurements. Tissue samples were also analysed for photosynthetic pigment, soluble protein, soluble sugar and malondialdehyde contents. All plants presented a shade-adapted profile, mostly revealed by their biochemical composition. In both species the chlorophyll a/chlorophyll b ratio decreased sharply whereas the total chlorophyll/total carotenoids and the total chlorophyll/soluble protein ratios increased. Soluble protein content was reduced more noticeably in Z. marina. Soluble sugars dropped almost 40% in Z. marina leaves and roots, a more pronounced effect than the one observed in C. nodosa. Overall, Z. marina revealed to be more sensitive than C. nodosa to reductions in incident irradiance, suggesting that it will be more sensitive to human-induced disturbances that result in an increase of water turbidity.
- Genomewide transcriptional reprogramming in the seagrass Cymodocea nodosa under experimental ocean acidificationPublication . Ruocco, Miriam; Musacchia, Francesco; Olivé, Irene; Costa, Monya; Barrote, Isabel; Santos, Rui; Sanges, Remo; Procaccini, Gabriele; Silva, JoãoHere, we report the first use of massive-scale RNA-sequencing to explore seagrass response to CO2-driven ocean acidification (OA). Large-scale gene expression changes in the seagrass Cymodocea nodosa occurred at CO2 levels projected by the end of the century. C. nodosa transcriptome was obtained using Illumina RNA-Seq technology and de novo assembly, and differential gene expression was explored in plants exposed to short-term high CO2/low pH conditions. At high pCO(2), there was a significant increased expression of transcripts associated with photosynthesis, including light reaction functions and CO2 fixation, and also to respiratory pathways, specifically for enzymes involved in glycolysis, in the tricarboxylic acid cycle and in the energy metabolism of the mitochondrial electron transport. The upregulation of respiratory metabolism is probably supported by the increased availability of photo-synthates and increased energy demand for biosynthesis and stress-related processes under elevated CO2 and low pH. The upregulation of several chaperones resembling heat stress-induced changes in gene expression highlighted the positive role these proteins play in tolerance to intracellular acid stress in seagrasses. OA further modifies C. nodosa secondary metabolism inducing the transcription of enzymes related to biosynthesis of carbon-based secondary compounds, in particular the synthesis of polyphenols and isoprenoid compounds that have a variety of biological functions including plant defence. By demonstrating which physiological processes are most sensitive to OA, this research provides a major advance in the understanding of seagrass metabolism in the context of altered seawater chemistry from global climate change.
- Glyphosate: a terrestrial threat to marine plants? a study on the seagrass zostera marinaPublication . Deguette, Alizé; Pes, Katia; Vasconcellos, Bernard; Costa, Monya; Silva, João; Barrote, IsabelGlyphosate-based herbicides (GBHs) are extensively used worldwide, raising concerns about their potential effect on non-target aquatic ecosystems. This study investigated the short-term physiological effects of a commercially available GBH on the seagrass Zostera marina under controlled mesocosm conditions. Z. marina individuals were exposed to three concentrations of glyphosate (0.165, 51, and 5100 mg L−1 ) for 4 days, and the impacts on photosynthetic performance, growth rate, photosynthetic pigments content and energy metabolism were assessed. Exposure to 5100 mg L−1 of glyphosate caused rapid water acidification and complete plant mortality within 24 h. Exposure to 51 mg L−1 of glyphosate significantly impaired photosynthetic efficiency and foliar growth rate. Energy availability, photosynthesis and photosynthetic pigments content were highly disrupted at both higher concentrations. Exposure to 0.165 mg L−1 of glyphosate decreased the foliar chlorophyll a/b ratio. These findings show that Z. marina can potentially be threatened by the presence of GBHs even at lower concentrations and underscore the necessity for monitoring herbicide pollution in coastal waters to protect seagrass habitats and associated ecosystems. Further research is needed to assess long-term effects and the role of herbicide formulations in mediating toxicity.
- Handling the heat: ocean acidification mitigates the effects of marine heatwaves on Posidonia oceanica seedlingsPublication . Pazzaglia, Jessica; Marín-Guirao, Lazaro; Ambrosino, Luca; Pes, Katia; Costa, Monya; Barrote, Isabel; Silva, João; Procaccini, Gabriele; Crysten Blaby-HaasOcean acidification and marine heatwaves are key drivers of marine ecosystem changes that can interact with one another and influence marine organisms. Seagrasses, including the long-lived Posidonia oceanica that is endemic to the Mediterranean Sea, are widely distributed along coastal habitats, forming highly valuable underwater meadows. The germination and survival of the early life stages of P. oceanica are strongly affected by environmental changes. To assess the impact of warming and acidification on its future, we conducted a multifactorial experiment in which P. oceanica seedlings were grown under ocean acidification conditions for 6 months and then exposed to a seawater warming event. Seedling performance was investigated by analysing photo-physiology, antioxidant capacity, energetic metabolism, and transcriptomic profiles. A weighted gene correlation network analysis was used to integrate phenotypic plant traits with transcriptomic results to identify central genes involved in plant responses to ocean acidification and temperature exposure. Results demonstrated that prolonged ocean acidification exposure enhances P. oceanica seedling resilience to marine heatwaves. Specifically, seedlings regulated their antioxidant systems and transcriptomic machinery to better cope with thermal stress. Under current CO2 concentrations, elevated temperatures induced stress in P. oceanica seedlings, impacting photosynthesis and respiration. However, ocean acidification could mitigate the impact of warming in the future, enhancing the resilience to global stressors of P. oceanica.
- Heatwave effects on the photosynthesis and antioxidant activity of the seagrass Cymodocea nodosa under contrasting light regimesPublication . Costa, Monya; Silva, João; Barrote, Isabel; Santos, RuiGlobal climate change, specifically the intensification of marine heatwaves, affect seagrasses. In the Ria Formosa, saturating light intensities may aggravate heatwave effects on seagrasses, particularly during low spring tides. However, the photophysiological and antioxidant responses of seagrasses to such extreme events are poorly known. Here, we evaluated the responses of Cymodocea nodosa exposed at 20 °C and 40 °C and 150 and 450 μmol quanta m−2 s−1. After four-days, we analyzed (a) photosynthetic responses to irradiance, maximum photochemical efficiency (Fv/Fm), the effective quantum yield of photosystem II (ɸPSII); (b) soluble sugars and starch; (c) photosynthetic pigments; (d) antioxidant responses (ascorbate peroxidase, APX; oxygen radical absorbance capacity, ORAC, and antioxidant capacity, TEAC); (d) oxidative damage (malondialdehyde, MDA). After four days at 40 °C, C. nodosa showed relevant changes in photosynthetic pigments, independent of light intensity. Increased TEAC and APX indicated an “investment” in the control of reactive oxygen species levels. Dark respiration and starch concentration increased, but soluble sugar concentrations were not affected, suggesting higher CO2 assimilation. Our results show that C. nodosa adjusts its photophysiological processes to successfully handle thermal stress, even under saturating light, and draws a promising perspective for C. nodosa resilience under climate change scenarios.
- Heterotrophic and photoautotrophic media optimization using response surface methodology for the Novel Microalga Chlorococcum amblystomatisPublication . Correia, Nádia; Pereira, Hugo; Schulze, Peter S.C.; Costa, Monya; Santo, Gonçalo E.; Guerra, Inês; Trovão dos Santos, Mafalda; Barros, Ana; Cardoso, Helena; Silva, Joana L.; Gouveia, Luisa; Varela, JoãoThe nutritional requirements of novel microalgal strains are key for their effective cultivation and metabolite content. Therefore, the optimization of heterotrophic and photoautotrophic culture media is crucial for novel Chlorococcum amblystomatis growth. Heterotrophic and photoautotrophic biomass samples were characterized to identify the differences between their heterotrophic and photoautotrophic biomass composition and their biotechnological potential. Media optimization through surface response methodology led to 44.9 and 51.2% increments in C. amblystomatis-specific growth rates under heterotrophic and photoautotrophic growth, respectively. This microalga registered high protein content (61.49–73.45% dry weight), with the highest value being observed in the optimized photoautotrophic growth medium. The lipid fraction mainly constituted polyunsaturated fatty acids, ranging from 44.47 to 51.41% for total fatty acids (TFA) in cells under heterotrophy. However, these contents became significantly higher (70.46–72.82% TFA) in cultures cultivated under photoautotrophy. An interesting carotenoids content was achieved in the cultures grown in optimized photoautotrophic medium: 5.84 mg·g−1 β-carotene, 5.27 mg·g−1 lutein, 3.66 mg·g−1 neoxanthin, and 0.75 mg·g−1 violaxanthin. Therefore, C. amblystomatis demonstrated an interesting growth performance and nutritional profile for food supplements and feed products that might contribute to meeting the world’s nutritional demand.
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