Search

Asparagopsis (Bonnemaisoniaceae, Rhodophyta) species are distributed in most temperate and tropical waters of the world, where they are considered an iconic invader. Despite a low number of species in the genus, Asparagopsis armata and A. taxiformis are considered species complexes, revealing remarkable genetic diversity in native and introduced distribution ranges. Macroscopic life stages that characterize the life cycle, gametophytes, and tetrasporophytes, present diferent morphologic, photosynthetic, physiological, and ecological features, which may aid in the course of an invasive process. Asparagopsis presence lowers diversity and abundance of native macroalgal communities. Despite hosting a relatively high number of epiphytes and epifauna, lower numbers are consistently found in these invasive species when compared to native fora. The chemical composition of A. armata and A. taxiformis and thus, its commercial applications have been studied since the 1970s. Recently, the discovery of its properties as a potent methane release inhibitor from ruminant animals has boosted a renewed scientifc, media, and commercial interest in the genus. Sourcing biomass remains a challenge, and while techniques of cultivation are available, more needs to be done to reach the scale needed to ft such large-volume application. Much is yet to be expected from this red algal genus. info:eu-repo/semantics/publishedVersion

Here we show the state of the art about biodiversity of seaweeds and seagrasses from the Alboran Sea. For this purpose, we revised the origin and biogeographical history shaping the present biodiversity of seaweeds and seagrasses, as well as the littoral landscapes dominated by these organisms. Furthermore, the locations with relevant importance for conservation of the biodiversity are analyzed, with emphasis on future directions in the management and conservation biology. Finally, we identify the main threats to the benthic flora of macroalgae and marine angiosperms in the Alboran Sea.

The mitochondrial genetic diversity, distribution and invasive potential of multiple cryptic operational taxonomic units (OTUs) of the red invasive seaweed Asparagopsis were assessed by studying introduced Mediterranean and Hawaiian populations. Invasive behavior of each Asparagopsis OTU was inferred from phylogeographic reconstructions, past historical demographic dynamics, recent range expansion assessments and future distributional predictions obtained from demographic models. Genealogical networks resolved Asparagopsis gametophytes and tetrasporophytes into four A. taxiformis and one A. armata cryptic OTUs. Falkenbergia isolates of A. taxiformis L3 were recovered for the first time in the western Mediterranean Sea and represent a new introduction for this area. Neutrality statistics supported past range expansion for A. taxiformis L1 and L2 in Hawaii. On the other hand, extreme geographic expansion and an increase in effective population size were found only for A. taxiformis L2 in the western Mediterranean Sea. Distribution models predicted shifts of the climatically suitable areas and population expansion for A. armata L1 and A. taxiformis L1 and L2. Our integrated study confirms a high invasive risk for A. taxiformis L1 and L2 in temperate and tropical areas. Despite the differences in predictions among modelling approaches, a number of regions were identified as zones with high invasion risk for A. taxiformis L2. Since range shifts are likely climate-driven phenomena, future invasive behavior cannot be excluded for the rest of the lineages.

SUMMARY In this study, we present basic population data of the red macroalga Asparagopsis taxiformis, widely recognized as invasive in the Mediterranean Sea. A 13-month field study was carried out on a population located in southern Spain, addressing its phenology, population dynamics and demography. We further tested whether biomass variations were related to environmental variables at the study site. Gametophytes were present year-round while tetrasporophytes were only found in spring and summer. Recruitment capacity and vegetative growth of the gametophytes are discussed as important modulators for the population structure and enhancers of its persistence. Thallus size-time histograms revealed a high prevalence of small shoots that showed high mortality that was not related to self-thinning. Biomass of A. taxiformis was higher from March to July. Vegetative growth was the main way the gametophyte population was maintained, although the presence of tetrasporophytes and fertile gametophytes in the field confirms that sexual reproduction also occurs. Its continuous and high recruitment, in terms of the number of smallest shoots, makes this southern population of A. taxiformis a source of future invasive populations due to the intensive maritime traffic in the region.

Although patellid limpets are influential grazers on many shores, few studies have characterised their diets in detail. These key species can be found as dominant grazers on rocky shores, but this ecosystem is being transformed due to the increase in infrastructures such as jetties, breakwaters or seawalls by commercial, residential and tourist activities. Increasing knowledge about the ecological effects of these artificial substrates on marine environments is available, and many papers have reported that urban infrastructures support different biota and assemblages and do not act as a surrogate for natural rocky shores. However, little is known about the effect of artificial substrata on marine trophic ecology. The aim of the study was to explore the influence of artificial substrata (breakwaters) on the dietary composition of the common grazer Patella caerulea, to provide data about food resource availability, and its influence on the trophic ecology of limpets. A nested design was used to explore potential differences between natural and artificial shores in Algeciras Bay (Strait of Gibraltar). Additionally, the dietary composition of the endangered limpets Cymbula safiana and Patella ferruginea was studied in a single site. Analyses of the chlorophyll a concentration of the substrate did not show differences between substrata. The analysis of the rock surface by SEM indicated a general prevalence of diatoms and cyanoprokaryotes on all of the substrata. P. caerulea specimens collected from artificial substrata showed a lower number of consumed taxa than those collected from natural rocky shores, whereas the assemblages found in the gut contents also differed between artificial and natural substrata. The diet richness of the three species might be due to the differences in the position of the species on the shore. Our results suggest that limpets are a key group in the top-down control of meiofaunal and macrofaunal populations, due to the presence of several animal taxa in their gut contents in this study, despite the fact that they have traditionally been considered herbivorous grazers that regulate only algal populations in the intertidal regions.

Contribuciones a la flora marina bentónica de las Islas Chafarinas (Mar de Alborán, Mediterráneo Occidental)Key words. Chafarinas Islands, geographical distribution, Mediterranean Sea, seaweeds.Palabras clave. Islas Chafarinas, corología, macroalgas marinas, Mediterráneo.

Asparagopsis taxiformis is a rhodophycean species composed of six genetic lineages, one of which is considered a relevant invasive component of Mediterranean flora. This study describes seasonal changes in the structure and biomass of the native community associated with A. taxiformis on the coast of Granada (southern Spain). The native community was represented by 18 Rhodophyta, 3 Chlorophyta, and 4 Ochrophyta species. Biomass was dominated by A. taxiformis and Halopteris filicina. In January, A. taxiformis represented only 16% of the whole community biomass, but 2 months later, more than 90% of the community biomass was formed by the invasive species. During the study period, species richness, the Shannon diversity index, and species evenness showed low and generally stable values. Given that A. taxiformis gametophytes are present throughout the year, they likely pose a constant stress to the development of the native community. This survey provides baseline information on the macroalgal community structure, which may be useful to further studies on the actual impact of the invasive lineage of A. taxiformis, This work was funded by the projects CGL2008/01549/ BOS (Ministerio de Ciencia e Innovación, Spain), P09- RNM-5187 (Consejería de Innovación, Ciencia y Empresa, Junta de Andalucía, Spain), 806/5.03.3553 and 806/5.03.3673 (Instituto de Estudios Ceutíes, Spain). It was developed in the framework of the Research Collaboration Agreement between Consejería de Medio Ambiente y Ordenación del Territorio de la Junta de Andalucía and the University of Málaga.

The invasive species Asparagopsis taxiformis (Bonnemaisoniales, Rhodophyta) on Andalusian coasts (Southern Spain): reproductive stages, new records and invaded communities. The present study provides new records from Andalusian coasts of the exotic invasive seaweed Asparagopsis taxiformis (Delile) Trevisan. These records demonstrate that A. taxiformis has rapidly and widely expanded its distribution range in this region, from Almería to Cádiz (Strait of Gibraltar). The latter locality may represent the western geographical limit of the species in the Mediterranean Sea. Spermatangial heads and cystocarps were observed in the collected gametophytes. Additionally, we report the first record of the tetrasporophytic stage, Falkenbergia hillebrandii (Bornet) Falkenberg from the Andalusian coast, although tetraspores were not encountered in these samples. Consequently, information on the affected communities and arguments for considering A. taxiformis as an invasive species in the Andalusian coast are provided.Key words. Asparagopsis taxiformis, Bonnemaisoniales, distribution, Falkenbergia hillebrandii, invasive species, Mediterranean Sea, new record, reproductive stage, RhodophytaRESUMEN. La especie invasora Asparagopsis taxiformis (Bonnemaisoniales, Rhodophyta) en las costas andaluzas (Sur de España): fases reproductivas, nuevas citas y comunidades invadidas. El presente trabajo aporta nuevas citas para las costas andaluzas de la especie exótica invasora de macroalga Asparagopsis taxiformis (Delile) Trevisan. Estas citas muestran que la especie ha aumentado ampliamente su área de distribución de manera rápida en esta región, desde Almería hasta Cádiz (Estrecho de Gibraltar). Esta última localidad representaría el límite occidental de la especie en el mar Mediterráneo. En las muestras recogidas de gametofitos se pudieron observar ramas espermatangiales y cistocarpos. Se aporta la primera cita del estadio tetrasporofítico, Falkenbergia hillebrandii (Bornet) Falkenberg en las costas andaluzas, aunque no se observaron tetrásporas en estas muestras. Se informa sobre las comunidades afectadas y se dan argumentos para considerar a A. taxiformis invasora en las costas andaluzas.Palabras clave. Asparagopsis taxiformis, Bonnemaisoniales, distribución, especie invasora, estadio reproductivo, Falkenbergia hillebrandii, mar Mediterráneo, nueva cita, Rhodophyta