Phenology and ecophysiology of macroalgae Porphyra spp. (Bangiales, Rhodophyta) and Lessonia spp. (Laminariales, Phaeophyceae) in north-central Chile: latitudinal and seasonal variations.

O propósito dos estudos fenológicos é descrever e compreender como o desenvolvimento dos organismos ocorre em resposta às variações ambientais que mudam ciclicamente e como certos fatores estimulam a geração de uma cascata de sinais e reações que abrangem desde mudanças moleculares, bioquímicas e fisiológicas, os que acabam se manifestando como padrões anuais de abundância e reprodução. As mudanças ambientais ocorrem em escalas temporais (diárias, sazonais, interanuais) e espaciais (latitudinal, em profundidade, em altitude) e têm um forte impacto no crescimento e desenvolvimento das espécies, em especial de aquelas com características sésseis. O objetivo deste estudo foi caracterizar os padrões fenológicos (sazonais e latitudinais) de abundância, reprodução, fotossíntese e capacidade antioxidante de dois gêneros de macroalgas de importância ecológica e econômica, Porphyra spp. (rodofícea) e Lessonia spp. (feofícea), distribuídas ao longo da costa norte e centro (25° - 34°S) do Chile. Os resultados mostram que variações sazonais de radiação e latitudinais de temperatura influenciam significativamente as respostas fenológicas e ecofisiológicas das espécies estudadas. No caso de Porphyra spp., o ajuste temporal mais notório envolve um desenvolvimento fenológico anual para a população do norte e perene para as do centro e sul. As características fisiológicas mostraram diminuição na eficiência fotossintetizante, pigmentos (clorofila α, carotenoides e ficobiliproteínas) e proteínas solúveis em primavera-verão, acompanhados por aumento da capacidade antioxidante. No caso de Lessonia e embora a abundância não tenha mostrado uma mudança sazonal nas populações, o ajuste temporal mais notório aconteceu nas características fisiológicas, com diminuição na eficiência fotossintetizante, pigmentos (clorofilas α e c, carotenoides), fenois e capacidade antioxidante durante o verão, acompanhado por aumento na absorptância do talo, ETRmax e NPQ. Estudos sobre as identidades taxonômicas das populações de Porphyra são necessários para distinguir entre possíveis padrões devido à caraterísticas da espécie de possíveis variações morfológicas ou ecotípicas. Estudos das espécies de Lessonia próximas aos seus limites de distribuição biogeográfica poderiam elucidar se as diferenças fenológicas e fisiológicas são devido a padrões dependentes das espécies ou são mascaradas por características ambientais locais. Os estudos fenológicos e as mudanças em nível bioquímico/fisiológico podem subsidiar novos destinos da biomassa produzida ou da matéria prima proveniente de organismos de importância econômica. Além disso, alterações nos padrões fenológicos e ecofisiológicos típicos podem direcionar a compreensão sobre os impactos de câmbios ambientais tais como os câmbios climáticos globais, contaminação e poluição, sobrexploração e as interações e dinâmica entre as populaçõesThe purpose of phenological studies is to describe and understand how the development of the organisms occurs in response to environmental variations which change cyclically and how certain factors stimulate the generation of signals and a cascade of reactions from molecular, biochemical and physiological levels, which at the end manifests annual patterns of abundance and reproduction. Environmental changes occur in time scale (daily, seasonal, interannual) and spatial scale (latitudinal, depth, altitude) and have a strong impact on growth and development of the species, especially those with sessile characteristics. The purpose of this study was to characterize the phenology (seasonal and latitudinal) of abundance, reproduction, photosynthesis and antioxidant capacity of two macroalgae with ecological and economic importance, Porphyra spp. (Rhodophyta) and Lessonia spp. (Phaeophyceae), distributed along the coast north and center (25° - 34°S) in Chile. The results show that seasonal changes in radiation and latitudinal temperature significantly influence the phenological and ecophysiological responses of the species studied. For Porphyra spp., the most notorious temporal adjustment involves an annual phenological development from north population in contrast to perennial populations from central and south. The physiological characteristics showed decrease in photosynthetic efficiency, pigments (chlorophyll a, carotenoids and phycobiliproteins) and soluble proteins in spring-summer, accompanied by increasing in antioxidant capacity. For Lessonia spp., although the abundance showed no seasonal changes between the populations, the most notoriously temporal adjustment occurs in physiological characteristics with decrease in photosynthetic efficiency, pigments (chlorophylls a and c, carotenoids), phenols and antioxidant capacity during the summer, followed by increase in thallus absorptance, ETRmax and NPQ. Studies on the taxonomic identity of Porphyra populations are required to distinguish between possible characteristics due to species-specific patterns from morphological or ecotypes variations. Studies in the species Lessonia near their limits of biogeographical distribution could elucidate whether the phenological and physiological differences are due to patterns species-specific or are masked by local environmental characteristics. The phenological studies and changes in the biochemical/physiological levels can subsidize new destination of biomass production and raw material from organisms economically important. Moreover, changes in typical phenological and ecophysiological patterns can give a light about environmental impacts of alterations such as global climate changes, contamination and pollution, overexploitation and interactions and dynamics between populations

Morphological variations of Gracilaria chilensis Bird, McLachlan et Oliveira, 1986 (Rhodophyta, Gracilariales) in the southeast Pacific Variaciones morfológicas de Gracilaria chilensis Bird, McLachlan et Oliveira, 1986 (Rhodophyta, Gracilariales) en el Pacífico Sureste

The present work is a population morphometric study of Gracilaria from different environments along a latitudinal gradient of the Chilean coast that cover 1,500 km. Gracilaria species have been extensively exploited with an average extraction of 75,000 t per year. In Chile this seaweed is usually found in sandy bottom bays between Antofagasta (23º29'S - 70º25'W) and Chiloé (42º03'0''S - 73º11'0''W). Observations were made in 51 plants. Macroscopic observations were done in fresh plants, microscopic characters were determined in transversal sections with 20% Karo syrup and stained with aniline blue. Numerical analyses were performed by one-way ANOVA and Principal Component Analysis. The latter analysis was performed for those characters with significant differences among the localities: basal constriction of branches, branch frequency, cortex cell diameter, subcortex cell diameter, thickness of the cortex and medullar cell diameter. The results of the Principal Component Analysis showed that 61% of the variance corresponded to the two first components. There were not observed groups clearly defined. The data suggest that along the coast of Chile there is only one morphotype that corresponds to the description of Gacilaria chilensis Bird, McLachlan et Oliveira, 1986 and it fits to the bulk of the material utilized in commercial production.<br>Este trabajo es un estudio morfológico de poblaciones de Gracilaria que habitan diferentes ambientes a lo largo de una gradiente latitudinal de la costa de Chile que cubre 1.500 Km. La especies de Gracilaria han sido extensivamente explotadas, con promedios de extracción de 75.000 toneladas anuales. El alga se encuentra en bahías de fondos arenosos, entre Antofagasta (23º29'S - 70º25'W) y Chiloé (42º03'0''S - 73º11'0''W). Fueron analizadas 51 plantas. Se realizaron observaciones macroscópicas en plantas frescas. Los caracteres microscópicos se determinaron en secciones teñidas con azul de anilina y montadas en una solución de miel Karo al 20%. Los análisis numéricos de los datos se realizaron mediante un ANOVA de una vía y un Análisis de Componentes Principales. Este último análisis se realizó para aquellos caracteres con diferencias significativas entre localidades: constricción basal de las ramificaciones, frecuencia de la ramificación, diámetro de las células de la corteza, diámetro de las células subcorticales, grosor de la corteza y diámetro de las células de la médula. Los resultados del Análisis de Componentes Principales mostraron que el 61% de la varianza correspondió a los 2 primeros componentes. No se observaron grupos claramente definidos. Los datos encontrados sugieren que a lo largo de la costa estudiada existe un solo morfotipo que corresponde a la descripción de Gracilaria chilensis Bird, McLachlan et Oliveira, 1986 y esta descripción concuerda con la mayoría del material que se emplea para un uso comercial

Author&apos;s personal copy Physiological acclimation of floating Macrocystis pyrifera to temperature and irradiance ensures long-term persistence at the sea surface at mid-latitudes

Large numbers of giant kelp rafts are floating along temperate coasts of the southern hemisphere, carrying a wide diversity of associated organisms with them. During voyages, floating kelps are exposed to strong variations in environmental conditions such as UV-radiation (UVR) and temperature that affect algal physiology, growth, and reproductive output. Consequently, it was predicted that the interactive effects of high temperature and UVR suppress algal persistence and reproductive output at the sea surface. This hypothesis was tested by exposing Macrocystis pyrifera (Linnaeus) C. Agardh sporophytes to two irradiance (PAR, PAR + UV) and three temperature (cool, ambient, warm) conditions. An outdoor-tank experiment with two consecutive runs (1st and 2nd) was conducted in northern-central Chile (30°S) to assess growth and physiological responses (pigment contents and photosynthesis) of floating M. pyrifera. Results showed that after being afloat for 15 days, algae physiologically acclimated efficiently to changing abiotic conditions by a decrease in pigment contents and dynamic photoinhibition. However, in kelps exposed to 20°C these acclimation processes operated at the expense of growth, resulting in reduced biomass gains, lower blade elongation rates, and diminished reproduction. Overall, floating M. pyrifera responded with high physiological plasticity to the tested UV regimes (UVB 30-100 kJm − 2 ; UVA 300-2000 kJm ), but under stressful temperature conditions (~20°C) photoacclimation processes are costly and an important fraction of the energy gained via photosynthesis becomes unavailable for algal growth. We suggest that at mid latitudes (25°S-40°S) detached sporophytes of M. pyrifera have the capacity to float for long time periods and over large distances at water temperatures b 20°C

Concise review of the genus Durvillaea Bory de Saint-Vincent, 1825

The genus Durvillaea includes six currently accepted species, as well as two newly proposed species. Durvillaea spp. have a diplontic life cycle, lack a free-living gametophyte and have oogamous reproduction. All Durvillaea species require rocky substrate for attachment and wave-exposed environments. These "southern bull kelps" occur exclusively in the Southern Hemisphere and are important foundation species, in most cases controlling local community structure, influencing biodiversity, and providing food and habitat for other culturally and economically important species. Most species are non-buoyant and these have restricted geographic ranges, in some cases endemic to small oceanic islands. Buoyant members of the genus are more widespread, with one species (Durvillaea antarctica) found throughout the subantarctic, Chile, and New Zealand. This chapter summarizes the taxonomy, biology, and economic importance of Durvillaea species, with a focus on aspects relevant to their availability and productivity as crop plants. Systematics, distribution, ecology, life histories, population status, harvesting times, protection, management and chemical composition are covered. Much of the available data are for the species Durvillaea antarctica, D. willana, and D. potatorum. The techniques used in harvesting and the human uses of Durvillaea spp. (e.g., as food) are described, along with recommendations for harvest timing and method

Short- and long-term acclimation patterns of the giant kelp Macrocystis pyrifera (Laminariales, Phaeophyceae) along a depth gradient

The giant kelp, Macrocystis pyrifera, is exposed to highly variable irradiance and temperature regimes across its geographic and vertical depth gradients. The objective of this study was to extend our understanding of algal acclimation strategies on different temporal scales to those varying abiotic conditions at various water depths. Different acclimation strategies to various water depths (0.2 and 4m) between different sampling times (Jan/Feb and Aug/Sept 2012; long-term acclimation) and more rapid adjustments to different depths (0.2, 2 and 4m; short-term acclimation) during 14d of transplantation were found. Adjustments of variable Chl a fluorescence, pigment composition (Chl c, fucoxanthin), and the de-epoxidation state of the xanthophyll cycle pigments were responsible for the development of different physiological states with respect to various solar radiation and temperature climates. Interestingly, the results indicated that phlorotannins are important during long-term acclimation while antioxidants have a crucial role during short-term acclimation. Furthermore, the results suggested that modifications in total lipids and fatty acid compositions apparently also might play a role in depth acclimation. In Aug/Sept (austral winter), M.pyrifera responded to the transplantation from 4m to 0.2m depth with a rise in the degree of saturation and a switch from shorter- to longer-chain fatty acids. These changes seem to be essential for the readjustment of thylakoid membranes and might, thus, facilitate efficient photosynthesis under changing irradiances and temperatures. Further experiments are needed to disentangle the relative contribution of solar radiation, temperature and also other abiotic parameters in the observed physiological changes