Dra. Tellier, Florence

Lessonia nigrescens used to be an abundant kelp species along the Chilean coast, but recent molecular studies revealed the existence of a L. nigrescens species complex, which includes the two cryptic species Lessonia berteroana and Lessonia spicata. Since these species have different distributions (16°S–30°S for L. berteroana and 29°S–42°S for L. spicata), they experience differences in environmental conditions, such as solar irradiance, seawater temperature and air exposure during low tide. This study tested to what extent the genetic distinctness of each of the two species [identified by a mitochondrial marker (atp8/trnS)] is reflected by ecophysiological traits (total lipids, fatty acid composition, phlorotannins, pigments and variable chlorophyll a fluorescence of PSII) in response to the respective environmental conditions, prevailing along the latitudinal gradient. We studied algal individuals from eight populations (27°S–32°S, including the species overlapping zone). Phlorotannins, pigments and Chl a fluorescence of PSII were most crucial for species-specific adaptations at the respective growth sites, whereas changes in total lipids and fatty acid compositions were negligible. Hence, species differentiation within the L. nigrescens complex is also manifested at the ecophysiological level. These findings may help to predict kelp responses towards future environmental changes.

Aim: This study examines how rafting on floating bull kelps can shape the biogeographic patterns of raft-associated species, and analyses the spatio-temporal variability of taxonomic richness and co-occurrences of epibionts on beach-cast rafts of Durvillaea antarctica along a latitudinal gradient. Location: Southeast Pacific, along ~1,700 km of coastline. Methods: We examined the epibionts on stranded individuals of D. antarctica on 33 beaches along the continental coast of Chile (28° S–42° S) within four biogeographic districts during the winter and summer of two years (2014/2015–2015/2016). Taxonomic richness and co-occurrences of epibionts within a holdfast were examined. Known geographic ranges and rafting ranges were compared to determine possible range expansions via rafting dispersal. Results: Sessile species were the most frequent epibionts. Taxonomic richness varied among biogeographic zones and seasons, and was higher between 33° S and 42° S than between 28° S and 33° S, particularly in summer compared to winter. Taxonomic richness decreased with floating time (indicated by the presence and size of Lepas spp.). Habitat-forming epibionts such as mytilid mussels, the polychaete Phragmatopoma moerchi and the seaweeds Gelidium lingulatum and Lessonia spicata favoured co-occurrences of other species within a holdfast, suggesting a habitat cascade (i.e. biogenic holdfast—sessile eco-engineers—other epibionts), while the boring isopod Limnoria chilensis and the excavating limpet Scurria scurra were negatively correlated with many other species. Some rafting epibiont species with low dispersal ability were found more than 100–300 km outside of their known geographic ranges, with more extensive ephemeral range extensions at the southern edge of their respective ranges, probably facilitated by higher availability of rafts in those areas. Main Conclusions: These findings confirm that raft-associated species are frequently dispersed outside their known geographic ranges, although these range extensions vary strongly depending on the availability and persistence of rafts, and on the biotic interactions within the rafting assemblage.

Morphological variability is common among macroalgae. In central Chile, Mazzaella laminarioides extends throughout the intertidal rocky zones, where blades are reported to grow up to 20 cm in length. Nevertheless, in low rocky intertidal zones with sand-influence, blades are noticeably larger than in other shores without sand effect. The aim of this study was to compare the morphology of M. laminarioides blades from two different conditions. Blades collected from four sites with, and four without, sand-influence were evaluated with traditional morphometry. Results showed that blades were longer and wider in sand-influenced sites. Sand abrasion was not directly evaluated, but indirect effects such as the abundance of bare rock and of sand tolerant species were higher in areas with sand-influence. Also, long blades were restricted to sand-influenced sites, supporting the relation between these two variables. Molecular analyses using the COI marker confirmed large-bladed individuals as M. laminarioides. Results indicated that life cycle phase, seasonality and vertical height were not related to large blades. We suggest that restriction of large blades to sand-influenced sites may be related to the healing processes of basal holdfasts after suffering sand abrasion.

Dispersal on floating seaweeds depends on availability, viability, and trajectories of the rafts. In the southern hemisphere, the bull kelp Durvillaea antarctica is one of the most common floating seaweeds, but phylogeographic studies had shown low connectivity between populations from continental Chile, which could be due to limitations in local supply and dispersal of floating kelps. To test this hypothesis, the spatiotemporal dynamics of kelp strandings were examined in four biogeographic districts along the Chilean coast (28°–42°S). We determined the biomass and demography of stranded individuals on 33 beaches for three subsequent years (2013, 2014, 2015) to examine whether rafting is restricted to certain districts and seasons (winter or summer). Stranded kelps were found on all beaches. Most kelps had only one stipe (one individual), although we also frequently found coalesced holdfasts with mature males and females, which would facilitate successful rafting dispersal, gamete release, and reproduction upon arrival. High biomasses of stranded kelps occurred in the northern-central (30°S–33°S) and southernmost districts (37°S–42°S), and lower biomasses in the northernmost (28°S–30°S) and southern-central districts (33°S–37°S). The highest percentages and sizes of epibionts (Lepas spp.), indicative of prolonged floating periods, were found on stranded kelps in the northernmost and southernmost districts. Based on these results, we conclude that rafting dispersal can vary regionally, being more common in the northernmost and southernmost districts, depending on intrinsic (seaweed biology) and extrinsic factors (shore morphology and oceanography) that affect local supply of kelps and regional hydrodynamics.

La sistemática de Bangiales foliosas ha tenido cambios significativos a nivel global, debido a la inclusión de nuevos géneros, como Pyropia, y la incorporación de la evidencia molecular. En Chile, la aplicación de herramientas moleculares ha evidenciado una alta diversidad de especies de los géneros Porphyra y Pyropia, con delimitaciones de especies que no corresponden a las especies definidas con base en caracteres morfológicos. En el Perú, los registros históricos reconocen cincoespecies de Porphyra; sin embargo, su estatus taxonómico aún no ha sido contrastado profundamente con la evidencia molecular. Por ello, este trabajo tuvo como objetivo explorar la diversidad local de las especies de los géneros Porphyra y Pyropia en Marcona, Perú, caracterizando 11 especímenes con los marcadores mitocondrial COI y cloroplastidial rbcL. El análisis filogenético identificó una especie de Porphyra (Porphyra sp. CHF) y tres especies de Pyropia (Pyropia orbicularis, Py. suborbiculata y Pyropia sp. CHI). No hubo coincidencia con los registros históricos de Porphyra. Tres de las cuatro especies encontradas tienen un rango de distribución que comprende Chile y Perú. Este trabajo es un primer avance hacia una caracterización de la diversidad específica del recurso algal conocido en Perú como “cochayuyo”.

Ship hull fouling is recognized as an important vector for the introduction of nonindigenous species (NIS), which has been studied globally but no empirical works exist in the Southeast Pacific. The present study examined fouling organisms on the hulls of three ships in one international Chilean port, and compared them with those on settling plates and natural substrates. Also, genetic analyses were perfomed on the most common NIS recorded in order to explore number and potential origin of the genetic linages found. The highest number of total taxa and NIS were found on ship hulls, with three species identified as NIS in ship samplings. Settling plates displayed the largest number of taxa, with a large abundance of the invasive tunicate Ciona robusta, which also showed high mitochondrial genetic diversity. This study showed that Chilean coasts are subjected to both NIS colonization and propagule pressure through ship hulls. Biosecurity measures should urgently be taken on ship hulls along these coasts.

Rafting on floating seaweeds facilitates dispersal of associated organisms, but there is little information on how rafting affects the genetic structure of epiphytic seaweeds. Previous studies indicate a high presence of seaweeds from the genus Gelidium attached to floating bull kelp Durvillaea antarctica (Chamisso) Hariot. Herein, we analyzed the phylogeographic patterns of Gelidium lingulatum (Kützing 1868) and G. rex (Santelices and Abbott 1985), species that are partially co-distributed along the Chilean coast (28°S–42°S). A total of 319 individuals from G. lingulatum and 179 from G. rex (20 and 11 benthic localities, respectively) were characterized using a mitochondrial marker (COI) and, for a subset, using a chloroplastic marker (rbcL). Gelidium lingulatum had higher genetic diversity, but its genetic structure did not follow a clear geographic pattern, while G. rex had less genetic diversity with a shallow genetic structure and a phylogeographic break coinciding with the phylogeographic discontinuity described for this region (29°S–33°S). In G. lingulatum, no isolation-by-distance was observed, in contrast to G. rex. The phylogeographic pattern of G. lingulatum could be explained mainly by rafting dispersal as an epiphyte of D. antarctica, although other mechanisms cannot be completely ruled out (e.g., human-mediated dispersal). The contrasting pattern observed in G. rex could be attributed to other factors such as intertidal distribution (i.e., G. rex occurs in the lower zone compared to G. lingulatum) or differential efficiency of recruitment after long-distance dispersal. This study indicates that rafting dispersal, in conjunction with the intertidal distribution, can modulate the phylogeographic patterns of seaweeds.

Harvest pressure on brown macroalgae of the Lessonia genus has increased in recent years in Peru and Chile, due to the high demand from the global hydrocolloid industry. After a taxonomic review, in 2012, the intertidal species Lessonia nigrescens was segregated into two species, being L. berteroana distributed in southern Peru and northern Chile (17-30°S). Based on genetic tools we confirm the identification as L. berteroana and report its presence up to 15°23’S. It is recommended to update the status of the species into Peruvian regulations and scientific publications.

Chondracanthus chamissoi is part of the diet of coastal people from Peru and is exported dehydrated to Asian countries for direct consumption. Although it is considered endemic to Peru and Chile, its range has extended to distant regions, such as Korea, Japan, and France. Using morphological and molecular approaches, we examined specimens from Peru assigned to C. chamissoi (including the taxon of uncertain status Chondracanthus glomeratus) to improve phylogenetic and geographical information and characterize its morphological variability.Twenty-one localities on the Peruvian coast were sampled, obtaining 102 COI and 27 rbcL sequences. To differentiate both entities, morphological characters such as thallus size, consistency, arrangement of main and secondary axes,branching patterns and location of reproductive structures,were analyzed on 46 specimens. While morphological characteristics are clearly contrasting among the two groups, both COI and rbcL phylogenies revealed a well-supported clade with no genetic differentiation between the two morphologies.Therefore, the phylogenies indicate that C. chamissoi and C. glomeratus form a single taxonomic entity with high morphological variability, large geographic distribution and at least two morphological forms. The smaller form of C. chamissoi can be identified as C. chamissoi f. glomeratus. Such morphological variability can be of interest for future aquaculture development.

The red seaweed Chondracanthus chamissoi shows high morphological variability. Initially, three species were identified based on the width of the main axis of their blades. Later, all of them were included in a single species with two morphological groups. Recently, quantitative studies demonstrated the existence of two forms in C. chamissoi: f. lessonii and f. chauvinii. It was also shown that these two forms occur in sympatry, growing side by side. These forms were not associated with either a life cycle phase or the sex of the blades. This study aimed to determine whether the two forms could represent different species. We evaluated the forms' taxonomic position using COI and rbcL markers, including samples from three localities in southern Chile. All specimens shared a single rbcL haplotype, whereas the two COI haplotypes differed by four base pairs and were present in blades of both forms and life cycle phases. The two morphological types correspond to intraspecific forms. This species is of commercial importance, and its main market is aimed at human consumption with a marked preference for f. lessonii.