Genetic diversity and biogeographical patterns of Caulerpa prolifera across the Mediterranean and Mediterranean/Atlantic transition zone

© 2015, Springer-Verlag Berlin Heidelberg. Knowledge of spatial patterns of genetic differentiation between populations is key to understanding processes in evolutionary history of biological species. Caulerpa is a genus of marine green algae, which has attracted much public attention, mainly because of the impacts of invasive species in the Mediterranean. However, very little is known about the ecological and evolutionary history of the Mediterranean native Caulerpa prolifera, a species which is currently found at sites distributed worldwide. C. prolifera provides a good model to explore the patterns of genetic diversity at different scales across the Mediterranean and Atlantic area. This study aims to investigate the biogeographical patterns of diversity and differentiation of C. prolifera in the Mediterranean, with special focus on the Mediterranean/Atlantic transition zone. We used two nuclear (ITS rDNA and the hypervariable microsatellite locus CaPr_J2) and one chloroplast (tufA) DNA markers on samples of C. prolifera from its entire range. Analyses of 51 sequences of the cpDNA tufA of C. prolifera, 87 ITS2 sequences and genotypes of 788 ramets of C. prolifera for the locus CaPr_J2 revealed three different biogeographical areas: West Atlantic, East Atlantic and a larger area representing the Mediterranean, the Mediterranean/Atlantic transition zone and a Pacific site (Bali). It was found out that the Mediterranean/Atlantic transition zone is a biogeographical boundary for C. prolifera. A lack of connectivity was revealed between Atlantic and Mediterranean types, and identical sequences found in the Mediterranean and Indo-Pacific suggest either recent gene flow along the Red Sea connection or a possible ancient Indo-Pacific origin.Financial support for this study was provided by several research projects: CAULERPA_GENETICS (PTDC/MAR/70921/2006) by FCT (Portuguese Science Foundation) co-funded by FEDER and a postdoctoral fellowship (SFRH/BPD/17206/2004) from FCT, Portugal, co-funded by FSE, both to EVA, EXCL/AAG-GLO/0661/2012 to ES, CAULEXPAN (Spanish Ministry of Education, REN2002-00701) to NM, MedVeg (EU contract no. Q5RS-2001-02456), PRADERAS by the Foundation BBVA (Banco Bilbao Vizcaya Argentaria) to CDPeer Reviewe

DNA barcoding reveals cryptic diversity, taxonomic conflicts and novel biogeographical insights in Cystoseira s.l. (Phaeophyceae)

Este artículo contiene 26 páginas, 8 figuras, 2 tablas.Cystoseira 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 ~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 cox1 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.This study was funded by the Portuguese Foundation for Science and Technology (FCT) through UIDB/04326/2020, UIDP/04326/2020 and LA/P/0101/2020, EU BiodivRestore253 (FCT: DivRestore/0013/2020), DL 57/2016/CP1361/ CT0010 (to JN), IF/01640/2015 (to PA) and SFRH/BSAB/ 150485/2019 (to EAS). JN has received funding from H2020 (EU) under grant agreement No 730984, Assemble Plus, DMF from Portuguese government grant Fundo Azul under the Seaforest Portugal Project (FA_06_2017_067), and EAS from a Pew Marine Fellowship. Sampling in West Africa was funded by projects MARAFRICA: FCTAGA-KHAN/540316524/2019, ‘Survie des Tortues Marines’ PRCM/STM POOOA4/OA9 by PRCM (Partenariat Régional pour la Conservation de la zone côtière et Marine en Afrique de l’Ouest) and ‘PNBA-site emblématique pour les tortues’ granted to the National Park of the Banc d’Arguin. BS was funded by AFRIMED Project, id EASME/EMFF/2017/1.2.1.12/S4/01/SI2.789059. DS has received funding from University of Catania in the frame of “PiaCeRi-Piano Incentivi per la Ricerca di Ateneo 2020-22, linea di intervento 2.Peer reviewe

GlobalHAB (IOC-UNESCO and SCOR): Latinamerica contribution to the international coordination for sound knowledge of HABs to manage their impacts

12th International Phycological CongressThe Global Harmful Algal Blooms (GlobalHAB, www.global hab.info) Program is aimed at fostering international cooperative research directed toward improving the prediction of harmful algal bloom (HAB) events in aquatic ecosystems, and providing sound knowledge for policy- and decision-making to manage and mitigate HAB impacts in a changing planet. GlobalHAB is sponsored by the Intergovernmental Oceanographic Commission (IOC) of UNESCO and the Scientific Committee on Oceanic Research (SCOR). GlobalHAB was launched in 2016 and will last for 10 years. The GlobalHAB scientific objectives are focused on the research of taxonomic, ecological and toxicology knowledge gaps, on the effects of climate change on HABs and their biogeographic distribution, the implementation of HABs observing systems, and overall, to promote aquatic food and water safety and security. The GlobalHAB program has an international nature, and collaborates with international entities and programs that share objectives on HABs research, management and mitigation, as was already done by the former program GEOHAB. In particular, scientists from Latin America were active participants in GEOHAB and today Latin America is key in the implementation of GlobalHAB. Extreme HAB events affecting aquaculture sites and natural environments, Sargassum beachings, HABs monitoring programs, ciguatera fish poisoning, toxin transfer through the food webs, are examples of topics where scientists in Latin America are very active and thus, contribute to the implementation of GlobalHAB. Scientists are invited to participate in GlobalHAB by designing and endorsing scientific activities linked to the goals of GlobalHAB, and by participating in other international activitiesThe GlobalHAB (www.globalhab.info) international program is funded by IOC UNESCO and SCORPeer reviewe

Projected climate changes threaten ancient refugia of kelp forests in the North Atlantic

Intraspecific genetic variability is critical for species adaptation and evolution and yet it is generally overlooked in projections of the biological consequences of climate change. We ask whether ongoing climate changes can cause the loss of important gene pools from North Atlantic relict kelp forests that persisted over glacial–interglacial cycles. We use ecological niche modelling to predict genetic diversity hotspots for eight species of large brown algae with different thermal tolerances (Arctic to warm temperate), estimated as regions of persistence throughout the Last Glacial Maximum (20,000 YBP), the warmer Mid‐Holocene (6,000 YBP), and the present. Changes in the genetic diversity within ancient refugia were projected for the future (year 2100) under two contrasting climate change scenarios (RCP2.6 and RCP8.5). Models predicted distributions that matched empirical distributions in cross‐validation, and identified distinct refugia at the low latitude ranges, which largely coincide among species with similar ecological niches. Transferred models into the future projected polewards expansions and substantial range losses in lower latitudes, where richer gene pools are expected (in Nova Scotia and Iberia for cold affinity species and Gibraltar, Alboran, and Morocco for warm‐temperate species). These effects were projected for both scenarios but were intensified under the extreme RCP8.5 scenario, with the complete borealization (circum‐Arctic colonization) of kelp forests, the redistribution of the biogeographical transitional zones of the North Atlantic, and the erosion of global gene pools across all species. As the geographic distribution of genetic variability is unknown for most marine species, our results represent a baseline for identification of locations potentially rich in unique phylogeographic lineages that are also climatic relics in threat of disappearing.This study was supported by the Pew Foundation and the Foundation for Science and Technology (FCT) of Portugal through the fellowship SFRH/BPD/111003/2015 and projects CCMAR/Multi/04326/2013, EXCL/AAG‐GLO/0661/2012, PTDC/MAR‐EST/6053/2014, and BIODIVERSA/004/2015. MBA acknowledges support from CIBIO‐UID/BIA/50027/2013 (POCI‐01‐0145‐FEDER‐006821), the Spanish National Research Council, and the Danish Natural Science Research Council for funding the Centre for Macroecology, Evolution and Climate.Peer Reviewe

Spatial assessment and impact of artisanal fisheries' activity in Cap de Creus

North western Mediterranean is characterized by a high fishing activity and consequently, the awareness to preserve and protect high ecological important areas has been recently on the scope. Cape Creus is lately being subjected of study in order to assess its values in the frame of European Directives. By combining existing data of artisanal fisheries’ components together with gathered seabed components, a spatial distribution of fishing activity is pretended. A spatial approach has been the main tool when assessing the consistency of fishing pressure onto the seabed. Benthic communities seem to be more affected when overlapping of fishing types occur. Consequently, alternating parceling and seasonal closures among fishing gear types, to minimize the impact onto benthic communities as also setting no-take zones is strongly suggested. The establishment of a MPA in the near future has to be seen for all stakeholders as one step contributing to the sustainability of the ecosystem, once the potential impact of this fishing activity is shown. Mid-scale benefits by means of reducing fishing pressure in the area will enhance both alternative income solutions and spillover offset as a result of habitat recoveryThis work was presented by the first author in order to complete the requirements to achieve the degree of Master of Science in Marine Biodiversity and Conservation, within the ERASMUS MUNDUS Master Programme EMBCPeer Reviewe

Molecular identification of the tropical seagrass Halophila stipulacea from Turkey

Halophila stipulacea (Forsskål) Ascherson, a tropical seagrass, is thought to be a Lessepsian immigrant that entered the Mediterranean Sea from the Red Sea after the opening of the Suez Canal (1869). Up to date, no genetic studies of H. stipulacea from Turkey are available. In order to verify the molecular identity of Turkish isolates of H, stipulacea, a part of the rDNAITS region was sequenced. Comparisons of the genetic polymorphism of this region between isolates from the Turkish coasts of the Aegean Sea and individuals from putative native (Red Sea) and introduced (Mediterranean) populations deposited previously in GenBank were performed. No intra-individual variability was found in the region considered among the isolates from Turkey.Peer Reviewe

Dinucleotide microsatellite markers in the genus Caulerpa

Caulerpa spp. are clonal green marine algae which often act as invasive species when growing outside their native biogeographical borders. Over the two past decades, Caulerpa taxifolia has spread along the Mediterranean coast, presently occurring at 70 sites and covering nearly 3,000 ha of subtidal area. New genetic markers (microsatellites) have been developed to assess clonal structure and genetic diversity of recently established populations of the invasive species C. taxifolia and Caulerpa racemosa in comparison with populations of the native Caulerpa prolifera in the Mediterranean. Our results show that nine polymorphic markers have been developed for C. prolifera, seven for C. taxifolia, and three for C. racemosa. Genetic diversity in Caulerpa was assessed in two geographical scales: one at a population scale where 40 thalli units were collected from C. prolifera in Cala d'Or, Mallorca, Spain, and another at a species scale, where 30 sample units were analyzed for C. prolifera, 24 for C. taxifolia, and 24 for C. racemosa from different sites in the Mediterranean, Atlantic, and Pacific Ocean. Number of alleles, expected heterozygosity, and marker amplification success are provided in each case. © 2010 Springer Science+Business Media B.V.This work was financed through the following projects: CAULEXPAN (REN 2002-00701), MACROALGAS INVASORAS (CTM2005-01434/MAR) by the MECD (Ministerio de Educación y Ciencia Español) to NM, PRADERAS by the Foundation BBVA (Banco Bilbao Vizcaya Argentaria) to CD, CAULERPA_GENETICS (PTDC/MAR/70921/2006) by FCT (Portuguese Science Foundation) co-funded by FEDER, and a Postdoctoral fellowship (SFRH/BPD/17206/2004) from FCT, Portugal, co-funded by FSE, both to EVA, by the NoE Marine Genomics Europe (GOCE-CT-2004-505403, WP6, algal node) to MV and ES, and supported in part by the Department of Energy award DE-FC09-07SR22506 to the University of Georgia Research Foundation.Peer Reviewe

Genomic DNA isolation from green and brown algae (Caulerpales and Fucales) for microsatellite library construction

A method for isolating high-quality DNA is presented for the green algae Caulerpa sp. (C. racemosa, C. prolifera, and C. taxifolia) and the brown alga Sargassum muticum. These are introduced, and invasive species in Europe, except for the native C. prolifera. Previous methods of extraction, using cetyl trimethyl ammonium bromide or various commercial kits, were used to isolate genomic DNA but either no DNA or DNA of very low quality was obtained. Genomic libraries were attempted with Caulerpa sp. on three occasions and either the restriction enzyme, the Taq polymerase, or the T4 ligase was inhibited, probably by the large amount of polysaccharides in these algae. The method presented here consists of the rapid isolation of stable nuclei, followed by DNA extraction. Yields of 6-10 μg genomic DNA from 1 g fresh blades were obtained. After genomic DNA was isolated from fresh material, the quality was checked by agarose gel. Quantification of DNA concentration was performed using UV spectrophotometric measurement of the A260/A280 ratio. The DNA was suitable for PCR, cloning, and hybridization. The DNA isolated using this method allowed successful construction of microsatellite libraries for Caulerpa species and S. muticum. The technique is inexpensive and appropriate for the isolation of multiple samples of DNA from a small amount of fresh material. © 2006 by the Phycological Society of America.Peer Reviewe

Metatranscriptomes reveal functional variation in diatom communities from the Antarctic Peninsula

© 2015 International Society for Microbial Ecology All rights reserved. Functional genomics of diatom-dominated communities fromthe Antarctic Peninsula was studied using comparative metatranscriptomics. Samples obtained from diatom-rich communities in the Bransfield Strait, the western Weddell Sea and sea ice in the Bellingshausen Sea/Wilkins Ice Shelf yielded more than 500K pyrosequencing reads that were combined to produce a global metatranscriptome assembly. Multi-gene phylogenies recovered three distinct communities, and diatom-assigned contigs further indicated little read-sharing between communities, validating an assembly-based annotation and analysis approach. Although functional analysis recovered a core of abundant shared annotations that were expressed across the three diatom communities, over 40% of annotations (but accounting for 3 - uptake and utilization all pointed to irradiance stress and/or inorganic carbon limitation within sea ice. Ice-binding proteins and cold-shock transcription factors were also enriched in sea ice diatoms. Surprisingly, the abundance of gene transcripts for the translational machinery tracked decreasing environmental temperature across only a 4 °C range, possibly reflecting constraints on translational efficiency and protein production in cold environments.This work was supported by grants 'SOPA' from the Portuguese Science Foundation (FCT; PTDC/MAR/72630) to GAP and is a contribution to the ATOS project (POL2006-00550/CTM) funded by the Spanish Ministry of Economy and Competitiveness (under the scope of the International Polar Year (IPY))Peer Reviewe

Enhancing the effectiveness of restoration actions in a changing ocean: insights from a transregional thermotolerance experiment

Second Annual Meeting Marine Ecosystem Restoration in Changing European Seas (MERCES), 23-25 May 2018, BarcelonaPeer Reviewe