| 1. |
- Felisberto, Paulo, et al.
(författare)
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Acoustic monitoring of O-2 production of a seagrass meadow
- 2015
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Ingår i: Journal of Experimental Marine Biology and Ecology. - : Elsevier BV. - 0022-0981 .- 1879-1697. ; 464, s. 75-87
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Tidskriftsartikel (refereegranskat)abstract
- Acoustic data were acquired in October 2011 over a Posidonia oceanica meadow in the Bay of la Revellata, Calvi, Corsica. The purpose was to develop an acoustic system for monitoring the oxygen (O-2) production of an entire seagrass meadow. In a shallow water area (<38 m), densely covered by P. oceanica, a sound source transmitted signals in 3 different bands (400-800 Hz, 1.5-3.5 kHz and 65-8.5 kHz) toward three self-recording hydrophones at a distance of 100 m, over the period of one week. The data show a high correlation between the diel cycle of the acoustic signals' energy received by the hydrophones and the temporal changes in water column O-2 concentration as measured by optodes. The results thus show that a simple acoustic acquisition system can be used to monitor the O-2-based productivity of a seagrass meadow at the ecosystem level with high temporal resolution. The finding of a significant production of O-2 as bubbles in seagrass ecosysterns suggests that net primary production is underestimated by methods that rely on the mass balance of dissolved O-2 measurements.
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| 2. |
- Moreira-Saporiti, Agustín, et al.
(författare)
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A trait-based framework for seagrass ecology : Trends and prospects
- 2023
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Ingår i: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 14
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Forskningsöversikt (refereegranskat)abstract
- In the last three decades, quantitative approaches that rely on organism traits instead of taxonomy have advanced different fields of ecological research through establishing the mechanistic links between environmental drivers, functional traits, and ecosystem functions. A research subfield where trait-based approaches have been frequently used but poorly synthesized is the ecology of seagrasses; marine angiosperms that colonized the ocean 100M YA and today make up productive yet threatened coastal ecosystems globally. Here, we compiled a comprehensive trait-based response-effect framework (TBF) which builds on previous concepts and ideas, including the use of traits for the study of community assembly processes, from dispersal and response to abiotic and biotic factors, to ecosystem function and service provision. We then apply this framework to the global seagrass literature, using a systematic review to identify the strengths, gaps, and opportunities of the field. Seagrass trait research has mostly focused on the effect of environmental drivers on traits, i.e., “environmental filtering” (72%), whereas links between traits and functions are less common (26.9%). Despite the richness of trait-based data available, concepts related to TBFs are rare in the seagrass literature (15% of studies), including the relative importance of neutral and niche assembly processes, or the influence of trait dominance or complementarity in ecosystem function provision. These knowledge gaps indicate ample potential for further research, highlighting the need to understand the links between the unique traits of seagrasses and the ecosystem services they provide.
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| 3. |
- Olsen, Jeanine L, et al.
(författare)
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The genome of the seagrass Zostera marina reveals angiosperm adaptation to the sea.
- 2016
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 530:7590, s. 331-5
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Tidskriftsartikel (refereegranskat)abstract
- Seagrasses colonized the sea on at least three independent occasions to form the basis of one of the most productive and widespread coastal ecosystems on the planet. Here we report the genome of Zostera marina (L.), the first, to our knowledge, marine angiosperm to be fully sequenced. This reveals unique insights into the genomic losses and gains involved in achieving the structural and physiological adaptations required for its marine lifestyle, arguably the most severe habitat shift ever accomplished by flowering plants. Key angiosperm innovations that were lost include the entire repertoire of stomatal genes, genes involved in the synthesis of terpenoids and ethylene signalling, and genes for ultraviolet protection and phytochromes for far-red sensing. Seagrasses have also regained functions enabling them to adjust to full salinity. Their cell walls contain all of the polysaccharides typical of land plants, but also contain polyanionic, low-methylated pectins and sulfated galactans, a feature shared with the cell walls of all macroalgae and that is important for ion homoeostasis, nutrient uptake and O2/CO2 exchange through leaf epidermal cells. The Z. marina genome resource will markedly advance a wide range of functional ecological studies from adaptation of marine ecosystems under climate warming, to unravelling the mechanisms of osmoregulation under high salinities that may further inform our understanding of the evolution of salt tolerance in crop plants.
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| 4. |
- Procaccini, Gabriele, et al.
(författare)
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Depth-specific fluctuations of gene expression and protein abundance modulate the photophysiology in the seagrass Posidonia oceanica
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Here we present the results of a multiple organizational level analysis conceived to identify acclimative/adaptive strategies exhibited by the seagrass Posidonia oceanica to the daily fluctuations in the light environment, at contrasting depths. We assessed changes in photophysiological parameters, leaf respiration, pigments, and protein and mRNA expression levels. The results show that the diel oscillations of P. oceanica photophysiological and respiratory responses were related to transcripts and proteins expression of the genes involved in those processes and that there was a response asynchrony between shallow and deep plants probably caused by the strong differences in the light environment. The photochemical pathway of energy use was more effective in shallow plants due to higher light availability, but these plants needed more investment in photoprotection and photorepair, requiring higher translation and protein synthesis than deep plants. The genetic differentiation between deep and shallow stands suggests the existence of locally adapted genotypes to contrasting light environments. The depth-specific diel rhythms of photosynthetic and respiratory processes, from molecular to physiological levels, must be considered in the management and conservation of these key coastal ecosystems.
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| 5. |
- Procaccini, Gabriele, et al.
(författare)
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Seagrass ecophysiology meets ecological genomics : are we ready?
- 2012
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Ingår i: Marine Ecolocy. - : Wiley. - 0173-9565 .- 1439-0485. ; 33:4, s. 522-527
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Tidskriftsartikel (refereegranskat)abstract
- In March 2011, the Ecophysiology and Genetics Working Groups of the European Science Foundation COST Action ES 0906, entitled Seagrass Productivity: From Genes to Ecosystem Management, organized an exploratory workshop entitled Linking Ecophysiology and Ecogenomics in Seagrass Systems. The goal of the workshop was to discuss how to integrate comparative gene expression studies with physiological processes such as photosynthetic performance, carbon and nitrogen utilization and environmental adaptation. The main questions discussed for integrative research related to mechanisms of carbon utilization, light requirements, temperature effects and natural variation in pH and ocean acidification. It was concluded that the seagrass research community is still in the nascent stages of linking ecophysiology with genomic responses, as carbon and nitrogen metabolism of seagrasses have not been sufficiently well studied. Likewise, genomic approaches have only been able to assign meaningful interpretations to a handful of differentially expressed genes. Nevertheless, the way forward has been established.
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| 6. |
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| 7. |
- Rasmusson, Lina M., et al.
(författare)
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Respiratory oxygen consumption in the seagrass Zostera marina varies on a diel basis and is partly affected by light
- 2017
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Ingår i: Marine Biology. - : Springer Science and Business Media LLC. - 0025-3162 .- 1432-1793. ; 164:6
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Tidskriftsartikel (refereegranskat)abstract
- The seagrass Zostera marina is an important marine ecosystem engineer, greatly influencing oxygen and carbon fluctuations in temperate coastal areas. Although photosynthetically driven gas fluxes are well studied, the impact of the plant's mitochondrial respiration on overall -CO2 and -O-2 fluxes in marine vegetated areas is not yet understood. Likewise, the gene expression in relation to the respiratory pathway has not been well analyzed in seagrasses. This study uses a combined approach, studying respiratory oxygen consumption rates in darkness simultaneously with changes in gene expression, with the aim of examining how respiratory oxygen consumption fluctuates on a diel basis. Measurements were first made in a field study where samples were taken directly from the ocean to the laboratory for estimations of respiratory rates. This was followed by a laboratory study where measurements of respiration and expression of genes known to be involved in mitochondrial respiration were conducted for 5 days under light conditions mimicking natural summer light (i.e.,15 h of light and 9 h of darkness), followed by 3 days of constant darkness to detect the presence of a potential circadian clock. In the field study, there was a clear diel variation in respiratory oxygen consumption with the highest rates in the late evening and at night (0.766 and 0.869 mu mol -O-2 m(-2) s(-1), respectively). These repetitive diel patterns were not seen in the laboratory, where water conditions (temperature, pH, and oxygen) showed minor fluctuations and only light varied. The gene expression analysis did not give clear evidence on drivers behind the respiratory fluxes; however, expression levels of the selected genes generally increased when the seagrass was kept in constant darkness. While light may influence mitochondrial respiratory fluxes, it appears that other environmental factors (e.g., temperature, pH, or oxygen) could be of significance too. As seagrasses substantially alter the proportions of both oxygen and inorganic carbon in the water column and respiration is a great driver of these alterations, we propose that acknowledging the presence of respiratory fluctuations in nature should be considered when estimating coastal carbon budgets. As dark respiration in field at midnight was approximately doubled from that of midday, great over-, or underestimations of the respiratory carbon dioxide release from seagrasses could be made if values are just obtained at one specific time point and considered constant.
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| 8. |
- Ruocco, Miriam, et al.
(författare)
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2b-RAD Genotyping of the Seagrass Cymodocea nodosa Along a Latitudinal Cline Identifies Candidate Genes for Environmental Adaptation
- 2022
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Ingår i: Frontiers in Genetics. - : Frontiers Media SA. - 1664-8021. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Plant populations distributed along broad latitudinal gradients often show patterns of clinal variation in genotype and phenotype. Differences in photoperiod and temperature cues across latitudes influence major phenological events, such as timing of flowering or seed dormancy. Here, we used an array of 4,941 SNPs derived from 2b-RAD genotyping to characterize population differentiation and levels of genetic and genotypic diversity of three populations of the seagrass Cymodocea nodosa along a latitudinal gradient extending across the Atlantic-Mediterranean boundary (i.e., Gran Canaria—Canary Islands, Faro—Portugal, and Ebro Delta—Spain). Our main goal was to search for potential outlier loci that could underlie adaptive differentiation of populations across the latitudinal distribution of the species. We hypothesized that such polymorphisms could be related to variation in photoperiod-temperature regime occurring across latitudes. The three populations were clearly differentiated and exhibited diverse levels of clonality and genetic diversity. Cymodocea nodosa from the Mediterranean displayed the highest genotypic richness, while the Portuguese population had the highest clonality values. Gran Canaria exhibited the lowest genetic diversity (as observed heterozygosity). Nine SNPs were reliably identified as outliers across the three sites by two different methods (i.e., BayeScan and pcadapt), and three SNPs could be associated to specific protein-coding genes by screening available C. nodosa transcriptomes. Two SNPs-carrying contigs encoded for transcription factors, while the other one encoded for an enzyme specifically involved in the regulation of flowering time, namely Lysine-specific histone demethylase 1 homolog 2. When analyzing biological processes enriched within the whole dataset of outlier SNPs identified by at least one method, “regulation of transcription” and “signalling” were among the most represented. Our results highlight the fundamental importance signal integration and gene-regulatory networks, as well as epigenetic regulation via DNA (de)methylation, could have for enabling adaptation of seagrass populations along environmental gradients.
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| 9. |
- Ruocco, Miriam, et al.
(författare)
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m6A RNA Methylation in Marine Plants: First Insights and Relevance for Biological Rhythms
- 2020
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1422-0067. ; 21:20
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Tidskriftsartikel (refereegranskat)abstract
- Circadian regulations are essential for enabling organisms to synchronize physiology with environmental light-dark cycles. Post-transcriptional RNA modifications still represent an understudied level of gene expression regulation in plants, although they could play crucial roles in environmental adaptation. N6-methyl-adenosine (m6A) is the most prevalent mRNA modification, established by “writer” and “eraser” proteins. It influences the clockwork in several taxa, but only few studies have been conducted in plants and none in marine plants. Here, we provided a first inventory of m6A-related genes in seagrasses and investigated daily changes in the global RNA methylation and transcript levels of writers and erasers in Cymodocea nodosa and Zostera marina. Both species showed methylation peaks during the dark period under the same photoperiod, despite exhibiting asynchronous changes in the m6A profile and related gene expression during a 24-h cycle. At contrasting latitudes, Z. marina populations displayed overlapping daily patterns of the m6A level and related gene expression. The observed rhythms are characteristic for each species and similar in populations of the same species with different photoperiods, suggesting the existence of an endogenous circadian control. Globally, our results indicate that m6A RNA methylation could widely contribute to circadian regulation in seagrasses, potentially affecting the photo-biological behaviour of these plants.
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| 10. |
- Tesson, Sylvie V.M., et al.
(författare)
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Mendelian Inheritance Pattern and High Mutation Rates of Microsatellite Alleles in the Diatom Pseudo-nitzschia multistriata.
- 2012
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Ingår i: Protist. - : Elsevier BV. - 1434-4610.
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Tidskriftsartikel (refereegranskat)abstract
- The diatom Pseudo-nitzschia multistriata exhibits a diplontic life cycle composed of an extensive phase of vegetative cell division and a brief phase of sexual reproduction. To explore genotypic stability, we genotyped seven polymorphic microsatellite loci in 26 monoclonal strains over 3-16 months in a culture maintenance regime. Moreover, to assess inheritance patterns of the microsatellite alleles, we genotyped 246 F1 strains resulting from four mating experiments between parental strains of know genotype. Results generally conformed expectations according to Mendelian inheritance patterns, but deviations were detected indicating mutations during sexual reproduction. A total of forty-two mutations were detected in the clonal cultures over time. Microsatellites with more core-repeats accumulated mutations faster. The mutation rate varied significantly across loci and strains. A binomial mass function and a computer simulation showed that the mutation rate was significantly higher during the first months of culture (μ≈3×10(-3) per locus per cell division) and decreased to μ≈1×10(-3) in the strains kept for 16 months. Our results suggest that genetic mutations acquired in both the vegetative phase and sexual reproduction add to the allelic diversity of microsatellites, and hence to the genotypic variation present in a natural population.
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| 11. |
- Tesson, Sylvie V.M., et al.
(författare)
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Microsatellite primers in the planktonic diatom Pseudo-nitzschia multistriata (Bacillariophyceae)
- 2011
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Ingår i: American Journal of Botany. - : Wiley. - 0002-9122. ; 98:2, s. 5-33
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Tidskriftsartikel (refereegranskat)abstract
- Premise of the study: Seven microsatellite loci were characterized for the toxic diatom Pseudo-nitzschia multistriata Takano (Takano) to investigate intraspecific variability and estimate population genetic structure over blooms, seasons, and sexual and vegetative reproduction. Methods and Results: Selected microsatellites consisted of di- and trinucleotide repeats in the core region, and showed four to twelve alleles per locus in strains of P. multistriata collected in the Gulf of Naples (Italy). Primer pairs were species-specific since they positively amplified against conspecific strains from Portugal and Spain but failed to generate PCR products from the diatoms Pseudo-nitzschia pseudodelicatissima (Hasle) Hasle and Leptocylindrus minimum Gran. Conclusions: The seven selected microsatellite markers will be useful in studying population dynamics of Pseudo-nitzschia multistriata in space and time.
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