Seasonal changes of macroalgae assemblages on the rocky shores of the Cape Horn Biosphere Reserve, Sub-Antarctic Channels, Chile

Recently 18 Bangiales seaweed species were reported for the Chilean coast, including Pyropia orbicularis and Pyropia variabilis (large [LM] and green [GM] morphotypes). Porphyra/Pyropia spp. occur mainly in the upper intertidal where desiccation stress is triggered by tidal fluctuations. However, the influence of environmental and ecophysiological variables and seasonal differences on Porphyra/Pyropia (microhabitats) intertidal distributions is unknown. Accordingly, we determined (i) the effect of environmental variables (temperature [T], relative humidity [RH], and photosynthetically active radiation [PAR]) and season on distribution, and (ii) physiological (cellular activity and lipid peroxidation [LPX]) and molecular responses (antioxidant enzymes expression at biochemical and transcript level) to desiccation stress in both Pyropia species and morphotypes (common garden experiment, on flat rocky platforms). Multivariate analyses of coverage and abundance in relation to environmental variables revealed a significant effect of temperature on P. variabilis GM distribution, GM dominating almost exclusively on rocky walls (where lowest PAR and T values but maximum RH were registered). Conversely, Pyropia orbicularis and Pyropia variabilis LM were found in high abundance on flat rocky platforms in summer, LM and GM also dominating flat rocky platforms in winter and spring. LPX and catalase activity did not differed among species in summer, while in winter activity and transcription of cat were higher in P. orbicularis than P. variabilis. Results suggest that tolerance to environmental stresses such as temperature could regulate the occurrence of P. variabilis GM on rocky walls; conversely, abundances of P. variabilis and P. orbicularis on flat rocky platforms would be also regulated by other abiotic and/or biotic factors.

Non-Random Distribution and Ecophysiological Differentiation of Pyropia Species (Bangiales, Rhodophyta) Through Environmental Gradients.

Controlled cultivation of different stages of Pyropia orbicularis (Rhodophyta; Bangiales) from the South Pacific coast

Abstract 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.

Effect of sand-influence on the morphology of Mazzaella laminarioides (Rhodophyta, Gigartinales) on rocky intertidal shores

Seasonal and Inter-Annual Dynamics of a Macrocystis Pyrifera Forest in Concepcion Bay, Chile

espanolResumen: El registro de la diversidad de algas permite reconocer especies que podrian generar informacion base para medidas de manejo, proteccion de los ambientes y presentar nuevas oportunidades de uso. En este contexto, el objetivo del presente trabajo fue determinar la riqueza, cobertura y composicion del ensamble de especies de macroalgas en la zona intermareal de Maitencillo, Valparaiso, Chile, durante 3 anos de monitoreo (2013-2015). Un total de 29 especies fueron registradas, donde 23 de ellas pertenecen a Rhodophyta, 3 a Ochrophyta; clase Phaeophyceae, y 3 a Chlorophyta. La riqueza de especies presento una alta variacion espacio-temporal en el area de estudio, donde las zonas del intermareal y las estaciones del ano presentaron un efecto significativo, explicando un 61 y 31% de su variabilidad, respectivamente. La mayor riqueza especifica se registro en las zonas media y baja (14 especies) durante primavera, y en la zona baja del intermareal (14) durante verano. Los menores valores fueron encontrados en la zona media (2) durante otono. Las zonas del intermareal demostraron ser la variable de mayor importancia a nivel de la comparacion del ensamble de algas, explicando el 53% de la variacion, mientras que la estacionalidad explico el 18% de esta. La mayor cobertura fue registrada en la zona media durante primavera, con predominio de Mazzaella laminarioides y Ulva spp. En la estacion de otono se obtuvo la menor cobertura debido a los procesos de acrecion de arena. En paredones dominaron especies del complejo Pyropia. Los resultados indicaron un claro patron de distribucion vertical y variacion estacional en el ensamble de macroalgas, destacando una mayor presencia de especies de Rhodophyta. La descripcion de la flora bentonica obtenida en este trabajo actualiza la diversidad de algas representativa de la Region de Valparaiso, Chile. EnglishAbstract: Records on the diversity of algae serve as a foundation for establishing management and environmental protection programs, as well as for determining new commercial uses of algae. With this context in mind, the goal of the present study was to determine the richness, coverage, and composition of the macroalgae assemblage in the intertidal zone of Maitencillo, Valparaiso, Chile over the course of 3 years (2013-2015). A total of 29 species were recorded from three phyla - 23 Rhodophyta; 3 Ochrophyta, of the Phaeophyceae class; and 3 Chlorophyta. Species richness presented high spatial and temporal variations, with these variations most significantly explained by intertidal zone (61%) and the seasons (31%). The highest levels of specific richness were recorded in the mid and lower intertidal zones (14 species) in spring, as well as in the lower intertidal zone (14 species) during summer. The lowest values of specific richness were recorded for the mid intertidal zone (2 species) during fall. The distinct levels of the intertidal zone also notably impacted algae assemblage, explaining 53% of variation while the seasons explained 18% of variation. The greatest coverage was recorded in the mid intertidal zone during spring, with a predominance of Mazzaella laminarioides and Ulva spp. complex. In turn, the lowest coverage was found in fall, linked with processes of sand accretion. In rocky walls, the Pyropia complex dominated. Results indicate a marked pattern of vertical and seasonal distribution in the macroalgae assemblage, as well as notably high presence of Rhodophyta species. This benthic flora description serves to update information on the diversity of representative algal species from Valparaiso Region of Chile.

/pdf/variacion-espacio-temporal-en-la-composicion-del-ensamble-de-upd52vjt3l.pdf

Variación espacio-temporal en la composición del ensamble de macroalgas del intermareal rocoso de Maitencillo, Valparaíso, costa central de Chile

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Variación espacio-temporal en la composición del ensamble de macroalgas del intermareal rocoso de Maitencillo, Valparaíso, costa central de Chile