Influencia de la vigilancia en una zona rocosa dentro de un área marina protegida, Pacífico Central de Costa Rica / Surveillance influence in a rocky shore within a marine protected area, Central Pacific of Costa Rica

Resumen Los intermareales rocosos son sitios importantes para peces, aves, invertebrados y algas entre otros, que se utilizan para la extracción de recursos alimenticios para las comunidades costeras. Se presentan los resultados de la evaluación de una costa rocosa en el Pacífico Central de Costa Rica (Refugio Nacional de Vida Silvestre Playa Hermosa-Punta Mala), usando indicadores biológicos propuestos por el protocolo del Ministerio de Ambiente y Energía. Se analizó la influencia de la vigilancia en dos sitios dentro de un AMP sobre el intermareal rocoso. La recolección de datos se realizó durante la época seca y la época lluviosa de 2015. Los datos mostraron que Nerita scabricosta presentó muchas colonias formadas por pocos individuos. La cobertura de macroalgas y los invertebrados bajo las rocas mostraron una leve diferencia entre los niveles de vigilancia. La densidad de Tetraclita stalactifera no mostró variaciones. Se sugiere la hipótesis que el daño mecánico asociado al turismo, pesca y extracción, está influyendo sobre los organismos de la zona rocosa. Algunos de los bioindicadores utilizados mostraron ser influenciados por los niveles de vigilancia y aplicación de las medidas de manejo.

Abstract Rocky intertidal are important sites for fish, birds, invertebrates and algae, among others, which are used for the extraction of food resources for coastal communities. We present the results of conservation assessment of a rocky shore in the Central Pacific of Costa Rica (Playa Hermosa-Punta Mala National Wildlife Refuge) using the biological indicators proposed by the National Environmental Ministry. This study aims to analyze the influence of surveillance, between two sites, over the rocky shore habitat. The sampling was carried out during both the dry and rainy seasons in 2015. Our data shows that Nerita scabricosta -harvested in small-scale fisheries- presents a high number of colonies formed by few individuals. Moreover, the abundance varied between seasons, probably due to a storm surge. Macroalgae differed slightly among sites, where turf had higher percentage coverage in low surveillance areas, while brown algae had higher coverage in high surveillance areas. Mechanical damage (abrasion due to rocks overturning) associated with tourism and harvesting could be influencing the low surveillance area, explaining these differences. Macroalgae presented a seasonal change, probably related to the storm surge. The density of the Tetraclita stalactifera did not exhibit variations. The surveillance level and enforcement influenced some bioindicators of the rocky shore, and therefore could be used to assess the extractive pressure. Rev. Biol. Trop. 66(3): 984-995. Epub 2018 September 01.

Caracterización espacial y biogeográfica de las asociaciones de macroalgas de Bahía del Rincón, Baja California Sur, México / Spatial and biogeographic characterization of macroalgal assemblages from Bahía del Rincón, Baja California Sur, Mexico

Macroalgal studies in Baja California Sur have dealt mainly with occurrence and seasonality, but some areas are poorly known even for these basic data. Bahía del Rincón-La Rivera is an important high-productivity fisheries area where coastal infrastructure development is under way. A spatial characterization of the marine flora from Bahía del Rincón-La Rivera was done by intensive sampling at different depths and localities with skin and SCUBA diving. At least 500m2 were surveyed in each site. Additionally, quantitative sampling was done in ten random 25 cm2 quadrates per site. In the intertidal section, density and cover estimates were used. We also investigated the historical records and geographical affinities. A total of 72 species were identified (most were red algae: 62%). We found no general trend in the biogeographical affinities, which varied with each taxonomic group. Most brown algae species were tropical-endemic; red algae temperate- cosmopolite and green algae tropical-cosmopolite. In the spatial assemblage structure we found a high similarity between the intertidal areas, but a low similarity in shallow or deeper areas (3-5 m). This pattern was the same when we compared the abundance of the main species. We suggest that there are significant spatial differences in recruitment and development of the assemblages in relation to vertical distribution (depth)and position along the shore. There is a clear-cut Gelidium-Jania belt in the intertidal zone and a Padina-Dictyota belt below the low tide. Sporadic and year-round species occur in the intertidal zone, annual and perennial species below the low tide line. Sites differ in recruitment and this affects the abundance of other species (such as coraline and Caulerpa species). Temperature and sedimentation affect seasonality, but community structure is relatively constant throughout the year

Se caracterizó la flora marina de la zona de Bahía del Rincón -La Rivera por medio de prospecciones intensivas en diferentes localidades a varias profundidades. Además, se realizó un análisis intenso de la literatura y por este mismo medio la determinación de las afinidades geográficas de las especies. En total se encontraron 72 especies, donde la mayor proporción (62%) correspondió a las algas rojas. En el caso de las afinidades biogeográficas se observó que la mayor proporción varió en función de la división, donde para algas cafés las predominantes fueron de naturaleza tropical/ endémica y para las algas rojas fueron las templadas/ cosmopolitas. Espacialmente se encontró una alta similitud entre las zonas someras estudiadas más no así entre las someras y profundas donde existen diferencias significativas. En el caso de la zona intermareal se determinaron diferencias significativas con áreas submareales y entre sitios de la zona somera y profunda basados en las abundancias de los principales taxa. Con base en los resultados se sugiere que existen diferencias verticales en reclutamiento y desarrollo de las poblaciones en relación a su distribución

The effect of temperature and irradiance on the growth and carotenogenic capacity of seven strains of Dunaliella salina (Chlorophyta) cultivated under laboratory conditions

The carotenogenic microalga Dunaliella salina is cultivated as a natural source of ¾ƒ-carotene. The 9-cis isomer of ¾ƒ-carotene is found only in natural sources having commercial advantages over the all-trans isomer due to its high liposolubility and antioxidant power. High irradiance appears to stimulate specifically all-trans ¾ƒ-carotene accumulationin D. salina, whereas low temperature apparently elicits ¾ƒ-carotene and 9-cis ¾ƒ-carotene production. We studied the effect of temperature and irradiance on the growth and the carotenogenesis of three Chilean (CONC-001, CONC-006 and CONC-007) and four non-Chilean (from Mexico, China, Australia and Israel) strains of D. salina cultivated under two photon flux densities (40 and 110 _ 6mol photons.m-2.s-1) and two temperatures (15 and 26ùª C). The Chilean strain CONC-001 and all of the non-Chilean strains exhibited the highest growth rates and the maximum cell densities, whereas the Chilean strains CONC-006 and CONC-007 showed the lowest values in both parameters. The Australian strain showed the highest accumulation of total carotenoids per unit volume (40.7 mg.L-1), whereas the Chilean strains CONC-006 and CONC-007, the only ones isolated from Andean environments, yielded the highest amounts of carotenoids per cell (61.1 and 92.4 pg.cell_1, respectively). Temperature was found to be more effective than irradiance in changing the qualitative and quantitative carotenoids composition. The Chilean strains accumulated 3.5-fold more ¾ƒ-carotene than the non-Chilean strains when exposed to 15ùª C and, unlike the non-Chilean strains, also accumulated this pigment at 26ùª C. The 9-cis/all-trans ¾ƒ-carotene ratio was > 1.0 in all treatments for all strains, and the values were not greatly influenced by either temperature or photon flux density. Physiological and biotechnological implications of these results are discussed.