Browsing by Author "Bermejo, Ricardo"
Now showing 1 - 6 of 6
Results Per Page
Sort Options
- A population genetics toolbox for the threatened canopy-forming brown seaweeds Cystoseira tamariscifolia and C-amentacea (Fucales, Sargassaceae)Publication . Engelen, Aschwin; Costa, Joana; Bermejo, Ricardo; Marba, NAria; Duarte, Carlos M.; Serro, Ester A.The brown macroalga Cystoseira tamariscifolia is a foundation species along the northeastern Atlantic and western Mediterranean Sea. It occurs from lower intertidal rock pools to the shallow subtidal. Anthropogenic pollution and rising seawater temperatures can threaten its local distributions. In order to address impacts of historical and current environmental changes, to quantify effective dispersal and population connectivity, and to provide genetic tools for restoration and coastal management strategies, we have developed ten microsatellite markers, validated on 48 individuals from a single population. With 2-11 alleles per locus, the observed heterozygosity varied between 0.244 and 0.875. All of the developed microsatellites cross-amplified also on Cystoseira amentacea. The ten microsatellite loci developed here show high genetic diversity, making them useful for connectivity and population genetic studies aimed at small to large spatial scales, and provide essential insight for the development of conservation strategies for this important but threatened foundation species.
- Biomass and nutrient dynamics of major green tides in Ireland: Implications for biomonitoringPublication . Bermejo, Ricardo; Golden, Nessa; Schrofner, Elena; Knöller, Kay; Fenton, Owen; Serrao, Ester; Morrison, LiamThe control of macroalgal bloom development is central for protecting estuarine ecosystems. The identification of the nutrients limiting the development of macroalgal blooms, and their most likely sources is crucial for management strategies. Three Irish estuaries (Argideen, Clonakilty and Tolka) affected by green tides were monitored from June 2016 to August 2017. During each sampling occasion, biomass abundances, tissue N and P contents, and δ15N were determined for tubular and laminar morphologies of Ulva. All estuaries showed maximum biomass during summer and minimum during winter. Tissue nutrient contents revealed P rather than N limitation. The δ15N during the peak bloom indicated agriculture as the most likely source of nitrogen in the Argideen and Clonakilty, and urban wastewaters in the Tolka. No differences in the δ15N, and the tissue nutrients content were observed between morphologies. The period between May and July is most suitable for bioassessment of green tides.
- DNA barcoding reveals cryptic diversity, taxonomic conflicts and novel biogeographical insights in Cystoseira s.l. (Phaeophyceae)Publication . Neiva, J.; Bermejo, Ricardo; Medrano, Alba; Capdevila, Pol; Milla-Figueras, David; Afonso, Pedro; Ballesteros, Enric; Sabour, Brahim; Serio, Donatella; Nóbrega, Eduardo; Soares, João; Valdazo, José; Tuya, Fernando; Mulas, Martina; Israel, Álvaro; Sadogurska, Sofia S.; Guiry, Michael D.; Pearson, Gareth; Serrao, EsterCystoseira sensu lato (s.l.) - encompassing the genera Cystoseira sensu stricto (s.s.), Ericaria and Gongolaria - is a diverse group of forest-forming brown macroalgae endemic to the warm-temperate North-east Atlantic. These algae have immense biogeographic and ecological significance and have been experiencing recent regional declines. Most Cystoseira s.l. display important morphological plasticity and can be confused with similar species. Therefore, species boundaries, geographic ranges and phylogenetic affinities remain imprecise for most. In the face of persistent taxonomic difficulties, several authors underlined the necessity for new molecular-based approaches, but studies so far lacked representativity, resolution and standardization. To fill in these gaps, in this study we sequenced a comprehensive collection of Cystoseira s.l. spanning its entire North-east Atlantic range for a similar to 1200 bp cox1 barcode, and sequenced selected individuals representing major genetic entities for a few additional plastid markers. Phylogeographic, phylogenetic and species delimitation methods revealed 27 Molecular Operational Taxonomic Units, including unaccounted cryptic diversity, and elucidated with unprecedented resolution species compositions and phylogenetic relationships within each genus. Some entities within the lineages Cystoseira compressa/humilis, Ericaria brachycarpa/crinita, E selaginoides and tophulose Gongolaria, as well as among free-living algae, conflicted with a priori taxonomic assignments, and required the redefinition, reinstatement and recognition of new taxa. For some, diagnostic mutations and biogeography were more useful for species identifications than morphological characters or conventional barcoding gaps. A few species showed narrow geographic ranges and others were the sole representatives of their respective lineages. Several sister-species showed Atlantic vs Mediterranean complementary ranges. phylogenetic signal of coxl was nevertheless insufficient to confidently determine patterns of lineage splitting in several lineages and species complexes and did not improve significantly with additional plastid markers. We discuss novel systematics and biogeography insights considering the advantages and shortcomings of the barcoding approach employed, and how this comprehensive baseline study can be expanded to address multiple questions still left unanswered.
- Improved phylogeny of brown algae Cystoseira (Fucales) from the Atlantic-Mediterranean region based on mitochondrial sequencesPublication . Bruno De Sousa, Carolina; Cox, Cymon; Brito, Luís; Pavão, Maria Madalena; Pereira, Hugo; Ferreira, Ana; Ginja, Catarina; Campino, Lenea; Bermejo, Ricardo; Parente, Manuela; J. C. or Varela J. or Varela J.C.S., VarelaCystoseira is a common brown algal genus widely distributed throughout the Atlantic and Mediterranean regions whose taxonomical assignment of specimens is often hampered by intra- and interspecific morphological variability. In this study, three mitochondrial regions, namely cytochrome oxidase subunit 1 (COI), 23S rDNA (23S), and 23S-tRNAVal intergenic spacer (mt-spacer) were used to analyse the phylogenetic relationships of 22 Cystoseira taxa (n = 93 samples). A total of 135 sequences (48 from COI, 43 from 23S and 44 from mt-spacer) were newly generated and analysed together with Cystoseira sequences (9 COI, 31 23S and 35 mt-spacer) from other authors. Phylogenetic analysis of these three markers identified 3 well-resolved clades and also corroborated the polyphyletic nature of the genus. The resolution of Cystoseira taxa within the three clades improves significantly when the inclusion of specimens of related genera was minimized. COI and mt-spacer markers resolved the phylogeny of some of the Cystoseira taxa, such as the C. baccata, C. foeniculacea and C. usneoides. Furthermore, trends between phylogeny, embryonic development and available chemotaxonomic classifications were identified, showing that phylogenetic, chemical and morphological data should be taken into account to study the evolutionary relationships among the algae currently classified as Cystoseira. The resolution of Cystoseira macroalgae into three well supported clades achieved here is relevant for a more accurate isolation and identification of natural compounds and the implementation of conservation measures for target species.
- Influence of irradiance, dissolved nutrients and salinity on the colour and nutritional characteristics of Gracilariopsis longissima (Rhodophyta)Publication . Bermejo, Ricardo; Macias, Manuel; Sanchez-Garcia, Fini; Love, Robyn; E, Varela-Álvarez; Hernandez, IgnacioColour is immediately perceived by the consumer and crucial for food product attractiveness. In this study, the possibility of obtaining different colour morphotypes in the rhodophyte Gracilariopsis longissima using short cultivation protocols (i.e. 9 days) was explored. In a first factorial experiment, the effects of salinity (25‰, 35‰ and 45‰), irradiance (60 and 270 μmol photons m− 1 s − 1 ) and nutrient conditions (N and P enrichment, no enrichment) on the growth, pigment concentration and colour of G. longissima were assessed. The results indicated that growth rate and phycocyanin were influenced by the three variables, whereas the concentration of other pigments (chlorophyll a, carotenoids and phycoerythrin) was significantly influenced by irradiance and nutrient conditions. The colour, defined as the Red, Green, Blue (RGB) signal from the photographed thalli, was mainly affected by irradiance and nutrient conditions. In a second experiment, four culture conditions yielding contrasting colour morphotypes and growth rates were repeatedly scaled up in the experiment to get enough biomass and to analyze nutritional properties (lipids, proteins, tissue N and P). The colour morphotypes and the corresponding culture conditions selected were: i) dark red; high salinity, low irradiance, nutrient enrichment; ii) light red; medium salinity, high irradiance, nutrient enrichment; iii) brownish; low salinity, low irradiance; no enrichment; and iv) green-yellowish; low salinity, high irradiance, no enrichment. These conditions caused marked differences in the nutritional properties of the thalli. The light red colour showed the best nutritional characteristics. Overall, G. longissima was not a suitable source of omega 3, but can be a source of Fe (0.34–0.53 mg g− 1 DW) and K (103–161 mg g− 1 DW), and its K:Na ratio can be enhanced under increasing salinity. The fast ecophysiological response, and its wide tolerance to environmental conditions, makes this species an excellent candidate for the development of short cultivation protocols.
- Marine forests of the Mediterranean-Atlantic Cystoseira tamariscifolia complex show a southern Iberian genetic hotspot and no reproductive isolation in parapatryPublication . Bermejo, Ricardo; Chefaoui, Rosa M.; Engelen, Aschwin H.; Buonomo, Roberto; Neiva, J.; Ferreira-Costa, Joana; Pearson, Gareth; Marba, Nuria; Duarte, Carlos M.; Airoldi, Laura; Hernandez, Ignacio; Guiry, Michael D.; Serrao, Ester A.Climate-driven range-shifts create evolutionary opportunities for allopatric divergence and subsequent contact, leading to genetic structuration and hybrid zones. We investigate how these processes influenced the evolution of a complex of three closely related Cystoseira spp., which are a key component of the Mediterranean-Atlantic seaweed forests that are undergoing population declines. The C. tamariscifolia complex, composed of C. tamariscifolia s.s., C. amentacea and C. mediterranea, have indistinct boundaries and natural hybridization is suspected. Our aims are to (1) infer the genetic structure and diversity of these species throughout their distribution ranges using microsatellite markers to identify ancient versus recent geographical populations, contact zones and reproductive barriers, and (2) hindcast past distributions using niche models to investigate the influence of past range shifts on genetic divergence at multiple spatial scales. Results supported a single, morphologically plastic species the genetic structure of which was incongruent with a priori species assignments. The low diversity and low singularity in northern European populations suggest recent colonization after the LGM. The southern Iberian genetic hotspot most likely results from the role of this area as a climatic refugium or a secondary contact zone between differentiated populations or both. We hypothesize that life-history traits (selfing, low dispersal) and prior colonization effects, rather than reproductive barriers, might explain the observed genetic discontinuities.