Search

This study aimed to compare the density of Isognomon bicolor on four rocky shores of the State of Espírito Santo, Brazil. Further, size and weight comparisons were undertaken for the flat and creviced surfaces. Quarterly samplings were taken in 2006 and 2007, by removing organisms from 10 x 10 cm quadrants in the mid-intertidal zone, with five samples from flat surfaces and five from crevices. Although densities of I. bicolor were considered low as compared with those of other studies, this species is well established in the State. The most well-established population of I. bicolor was found in the rock crevices. The most important factor for the establishment of I. bicolor on rocky shores is substrate heterogeneity.O objetivo deste estudo foi comparar a densidade de Isognomon bicolor em quatro costões rochosos no Espírito Santo, Brasil. Além disso, comparações do tamanho e do peso foram feitas para as superfícies lisas e com fendas. Coletas trimestrais foram realizadas entre 2006 e 2007, os organismos foram removidos utilizando um quadrado de 100 cm² na faixa do médiolitoral, sendo cinco nas superfícies lisas e cinco nas fendas. As densidades de I. bicolor foram consideradas baixas em comparação com outros estudos, mas a espécie encontra-se bem estabelecida. Foi obtido um maior número de indivíduos nas fendas. O fator mais importante para o estabelecimento de I. bicolor nos costões rochosos estudados mostrou ser a heterogeneidade do substrato.

O levantamento das espécies pertencentes aos gêneros de grandes parmélias do litoral centro-sul do Estado de São Paulo revelou a ocorrência de sete espécies de Parmotrema (talos foliosos de lobos arredondados em geral com mais de 0,5 cm larg. com margens inferiores não rizinadas) contendo como constituintes químicos medulares os ácidos girofórico e lecanórico, tipicamente reconhecidos pela cor avermelhada que resulta dos testes de coloração com hipoclorito de cálcio. São apresentados uma chave de identificação, descrições, comentários e ilustrações baseados em material brasileiro.In a survey of the species pertaining to genera of large parmeliae occurring in the coastal areas of central-southern São Paulo state, Brazil, seven species of Parmotrema (foliose thalli with rounded lobes usually more than 0.5 cm wide with nude lower margins) containing gyrophoric and lecanoric acids as main medullar substances were found. These are typically recognized by the red staining calcium hypochlorite spot tests. Identification key, descriptions, comments, and illustrations based on Brazilian material are provided for these species.

During six consecutive months, sampling were made at three points located on Governador Island and three on Paquetá Island in Guanabara Bay, Rio de Janeiro, Brazil. Material was collected from dock pilings and rocks in the intertidal zone. In these samples, five species belonging to three families, Corynidae, Kirchenpaueriidae and Campanulariidae, were identified. The campanulariid species Obelia dichotoma Linnaeus, 1758, dominated at nearly all points sampled. The small number of species obtained in this survey is attributed to the intense pollution in the bay, which borders the second-largest industrial complex and the second-largest demographic center of Brazil.Durante seis meses consecutivos foram feitas coletas em três pontos localizados na ilha do Governador e três em Paquetá, sendo colhido material em pilares de cais e rochas na zona entremarés. Foram identificadas cinco espécies pertencentes a três famílias: Corynidae, Kirchenpaueriidae e Campanulariidae. A espécie Obelia dichotoma Linnaeus, 1758 dominou em praticamente todos os pontos. O pequeno número de espécies encontradas neste levantamento deve-se, provavelmente, ao alto grau de poluição atualmente existente na baía, uma vez que ela abriga o segundo maior polo industrial e o segundo maior centro demográfico do Brasil.

Polychaeta are the most important benthic .animal sand consist of many species with a vital role in food web. We conducted a survey froin, summer 2005 to spring 2006 to complete the ecological studies of macro benthos in rocky shotes of the intertidal zone of the Hormouz Island. Three main regions were studied in the west, south and south-eastern parts and three transects were sampled in each region to test variation in Polychaeta distribution and abundance along the entire intertidal zone. At each one of the nine transects the shore was levelled and a general qualitative description was made, which also aided in the stratification of subsequent quantitative sampling. Samples were fixed in %4 formalin and transported to lab for analysis. Results showed presence of 10 genera of Polychaeta among which Nereis was the most abundant in the intertidal rocky shores. Our study also revealed seasonal and zonal distribution of Polychaeta in rocky shores of the area. Abundance of Polychaeta was markedly higher in summer compared to winter and in the upper zone compared with the mid littoral zone. Results of Shannon and Simpson diversity indexes affirmed above conclusion.

Community and population recovery from disturbance depends on the intensity, spatial scales, and frequency of disturbance events. Moreover, foundation species, like bed-forming mussels in rocky intertidal shores, are especially prone to disturbance associated with extreme climatic events. The aim of the present study was to experimentally evaluate how the frequency of physical disturbances that generate gaps in beds of the mussel Brachidontes rodriguezii affects mussel recolonization and the succession process on two rocky shore sites of the Southwestern Atlantic. Experimental disturbances (removal of mussels and other forms of biotic cover) were applied to small plots (14 cm × 14 cm) at three different frequencies over two years: 1) only at the beginning of the experiment (i.e., 1× removal frequency), 2) at the beginning of the experiment and 12 months later (2× removal frequency) and, 3) at the beginning of the experiment and 6, 12, and 18 later (4× removal frequency). Unmanipulated areas were maintained as controls. Before applying the experimental disturbance, we measured the abundance of all organisms present in all plots, obtaining data every 6 months. The data were analyzed considering two factors associated with the disturbance frequency: the time since the last removal and the number of removals on the same plot. Our results indicate that increases in disturbance frequencies were sufficient to maintain mussel bed recovery below control levels and increased the cover of crustose algae at the end of the two-year experimental period in one of the rocky shores studied. The decreases observed in the mussel recovery rates under increased disturbance scenarios are expected to have cascading consequences on rocky shore biodiversity, such as reductions in the overall abundance of interstitial invertebrate species that depend on mussel bed habitats and increases in the abundance of sessile organisms that preferentially occur in gaps and are otherwise excluded by mussels, such as the non-native barnacle Balanus glandula. • Mussel bed recovery in rocky shores decreases with increasing disturbance frequency. • Increased disturbances could be prevent mussel bed recovery. • Crustose algae becomes dominant as disturbance frequencies increase. [ABSTRACT FROM AUTHOR]

Plicopurpura patula pansa es un caracol carnívoro característico de las costas rocosas del Pacífico mexicano. Presenta una glándula hipobraquial que secreta un fluido que adquiere una coloración púrpura en presencia de oxígeno y luz solar. Se determinó el arreglo espacial del caracol en playas que difieren en cuanto al tipo de sustrato, exposición al oleaje y pendiente de playa. Se calculó entre 0.1522 y 0.5435. Las menores fluctuaciones del Ip se presentaron en 5 playas que tienen en común sustratos fijos, gran cantidad de grietas y oquedades. Las mayores fluctuaciones correspondieron a 4 playas con sustratos móviles, como los cantos rodados.Plicopurpura patula pansa is a carnivore snail common of the Mexican Pacific rocky shores. Its hypobranchial gland produces a secretion that, in the presence of oxygen and sunlight, becomes purple. We determined the spatial distribution of the snail on beaches that differ in substratum, wave exposure, and the degree substratum’s inclination. The average snail density was calculated. Using the Morisita index (Id) and the Morisita standardized index (Ip), we found that in 96.3% of the samples taken, the snails were distributed according to a patchy distribution. The rest of the time, their distribution was random. The I index oscillated between 0.1522 and 0.5435. Smaller fluctuations of the I index were observed in 5 beaches with substrata that were more stable and had a larger number of cracks and crevices than those on beaches with mobile substrata, such as rolled rocks.

Bioengineers modify habitats via their own physical structures and substantially increase local diversity in marine ecosystems. On rocky shores, there are large overlaps in the composition of communities associated with bioengineers that form complex mat-like habitats. We investigated the potential for redundancy in habitat provision by these types of habitats by comparing diverse molluscan assemblages associated with Perumytilus purpuratus mussel beds and algal turfs of Corallina officinalis var. chilenis, Gelidium chilense and Gastroclonium cylindricum. At three times between September 2003 and January 2004, we sampled the molluscan assemblages associated with each bioengineer at similar tidal heights on two rocky shores on the coast of central Chile. Of the 31 molluscan species identified, 30 were found in Corallina and 19-22 were identified from the other habitats. The pool of species found associated with each bioengineer overlapped greatly, demonstrating the potential for redundancy in habitat provision and little habitat-specificity. However, multivariate and univariate analyses showed all bioengineers except Gastroclonium contained a unique molluscan assemblage for at least one time of sampling because of variation in frequency of occurrence, richness and total abundance. Recent studies have highlighted many anthropogenic and natural processes that directly influence the diversity and composition of bioengineering species on rocky shores. We demonstrate that the loss of any particular bioengineer would not substantially alter the overall pool of molluscan species on the rocky shores of Chile. The loss of any bioengineer except Gastroclonium would, however, result in decreased local biodiversity because the molluscan assemblages in Perumytilus, Corallina and Gelidium, each contained a significantly different community structure for at least one time of samplingEn los ecosistemas marinos los organismos bioingenieros modifican habitats a través de sus propias estructuras físicas e incrementan la diversidad local. En costas rocosas existen grandes solapamientos en la composición de las comunidades asociadas a bioingenieros que forman habitats frondosos (algas) o mitílidos. Nosotros investigamos la potencial redundancia en la provisión de este tipo de habitat comparando ensambles faunísticos asociados a mantos de Perumytilus purpuratus y frondas de Corallina officinalis var. chilenis, Gelidium chilense y Gastroclonium cylindricum. En tres oportunidades, entre septiembre de 2003 y enero de 2004, muestreamos ensambles de moluscos asociados a cada uno de estos bioingenieros, en alturas de mareas similares en dos áreas rocosas de Chile central. De las 31 especies de moluscos identificados, 30 fueron encontrados en Corallina y 19-22 fueron identificados en los otros habitat. El conjunto de especies asociado a cada bioingeniero se sobrepone ampliamente, demostrando el potencial de redundancia en la provisión de habitat y poca especificidad de habitat. Sin embargo, análisis multivariados y univariados mostraron que los bioingenieros, con excepción de Gastroclonium, contenían un ensamble de moluscos único en al menos uno de los periodos de muestreo, ya sea en la variación en la frecuencia de ocurrencia, riqueza y abundancia total. Estudios recientes han destacado diversos procesos antropogénicos y naturales que influencian directamente la diversidad y composición de especies en bioingenieros de costas rocosas. Se demuestra que para la costa de Chile central la pérdida de cualquier de los bioingenieros analizados no alteraría sustancialmente el conjunto total de especies de moluscos, alojados en ellos. Sin embargo, la pérdida de cualquier bioingeniero, excepto Gastroclonium, resultaría en una disminución local de la biodiversidad debido a que cada uno de los ensambles de moluscos en Perumytilus, Corallina y Gelidium, contiene una estructura comunitaria significativamente diferente, en al menos uno de los periodos de muestreo

The Portuguese coast is located in a biogeographical transition zone between temperate and subtropical waters making it especially vulnerable to the effects of climate change. Several fish species struggle to cope with these annual changing conditions, particularly species that strongly depend on intertidal habitats which are expected to endure higher ecological fluctuations. Sand smelt young recruits and larvae were collected at the west coast of Portugal in the intertidal by hand-netting, and in the subtidal with light traps and scuba diving with plankton nets attached to scooters (Parede/Avencas: 38º 41’ N, 9º 21’W and Arrábida: 38º 28’ N, 8º 59’W, respectively). Due to the morphological similarities with other congeneric species young specimens were regularly collected and identified through genetic analysis. All samples were assigned to the same species: A. presbyter. Results showed that A. presbyter is one of the most abundant non-resident fish species in these rocky coastal areas, representing 49% (n=93.958) of the total number of individuals sighted in the intertidal from 2009-2015, but only 0.55% of the total number of individuals sampled in the subtidal (n=176 with both methods) from 2011-2013. Distribution patterns showed that recruits (TL 0.8-6.8 cm) concentrated within the intertidal area between March and December. Younger cohorts (TL 0.8-1.2 cm) are captured almost exclusively in these areas including confined intertidal channels and large pools between March and August, suggesting that reproduction and spawning can occur for a period of 6 months. Inter-annual seasonal variations from 2009 to 2015 showed irregular water temperature profiles, especially in 2011 and 2012, which may dramatically affect the reproductive success of this species, not only reducing the number of recruits but also shortening the recruitment period from 10 to 5 months. Globally, 46% of the coastlines have experienced a significant decrease in the frequency of extremely cold events, becoming more common the occurrence of extremely hot events and fast temperature variations. As sand smelt is one of the most abundant cold/temperate fish species in temperate waters and a common prey item of many piscivorous species, a reduction of its reproductive success may unbalance food web relationships in temperate coastal communities and affect local fisheries economy.

Global seascapes are increasingly modified to support high levels of human activity in the coastal zone. Modifications include the addition of defense structures and boating infrastructure, such as seawalls and marinas that replace natural habitats. Artificial structures support different macrofaunal communities to those found on natural rocky shores; however, little is known about differences in microbial community structure or function in urban seascapes. Understanding how artificial constructions in marine environments influence microbial communities is important as these assemblages contribute to many basic ecological processes. In this study, the bacterial communities of intertidal biofilms were compared between artificial structures (seawalls) and natural habitats (rocky shores) within Sydney Harbour. Plots were cleared on each type of habitat at 8 locations. After 3 weeks the newly formed biofilm was sampled and the 16S rRNA gene sequenced using the Illumina Miseq platform. To account for differences in orientation and substrate material between seawalls and rocky shores that might have influenced our survey, we also deployed recruitment blocks next to the habitats at all locations for 3 weeks and then sampled and sequenced their microbial communities. Intertidal bacterial community structure sampled from plots differed between seawalls and rocky shores, but when substrate material, age and orientation were kept constant (with recruitment blocks) then bacterial communities were similar in composition and structure among habitats. This suggests that changes in bacterial communities on seawalls are not related to environmental differences between locations, but may be related to other intrinsic factors that differ between the habitats such as orientation, complexity or predation. This is one of the first comparisons of intertidal microbial communities on natural and artificial surfaces and illustrates substantial ecological differences with potential consequences for biofilm function and the recruitment of macrofauna.

An ecological classification at the local scale may be a useful tool for conservation planning and for the implementation of specific management programmes in a region. For this purpose, a methodology previously applied on a small scale has been adapted to classify the coast of Cantabria (N Spain). This methodology includes a physical classification and biological validation. The shoreline was divided into 1 km stretches, and the abiotic variables (sea surface temperature, photosynthetically active radiation, significant wave height and coastal morphology) were recorded for each stretch. A hierarchical classification was proposed, with a first level that encompassed a grouping of quantitative variables based on SOM and k-mean analysis and a second level that subdivided the previous groups according to the categorical variable ‘coastal morphology’. To validate the classification using biological data, cover of intertidal macroalgal species was obtained at 14 sites along the study area, and several statistical analyses were applied to test the ecological significance of this classification. Three physical units were obtained (western (W), central (C) and eastern (E) coast), based on abiotic variables. Each group was then subdivided into subunits according to its coastal morphology (cliffs or wave-cut platforms). A general agreement between the macroalgal distribution and physical units was accomplished. In the lower intertidal,Bifurcaria bifurcataandHalopteris scopariadominated the western and central areas, whereasCorallinaspp./Ellisolandia elongataandGelidiumspp. were most abundant towards the east. In contrast, throughout the middle intertidal,Corallina. spp./E. elongatawere the dominant taxa. The classification system developed in this study completes a hierarchical framework for classifying the NE Atlantic coast, a promising approach that permits the application of the most suitable resolution in each case study that could be applicable to a wide range of coastal areas. [ABSTRACT FROM PUBLISHER]

The aim of this study was to attempt to fill current knowledge gaps on midlittoral Mediterranean biodiversity at local and regional scales, by using benthic polychaetes as a model taxon. Two different data sets were analysed: (i) a quantitative data set from the two Natural Geography in Shore Areas (Na GISA) study sites in Crete and (ii) a qualitative data set from multiple sites across the Mediterranean. At the local scale, the results provide evidence that (i) discrete species communities are formed in midlittoral Mediterranean habitats, which vary by geographical location and year, depending on the scale of observation; (ii) macrophyte coverage and Chl- a are the only environmental variables associated, albeit weakly, with the above pattern; (iii) although naturally disturbed, the Cretan Na GISA sites do not seem to experience any anthropogenic stress; (iv) environmental heterogeneity and history seem to be much less important in shaping the polychaete communities than inter-specific interactions; however, it is not possible to specify at this stage whether local or regional processes or even their interactions may shape the polychaete communities. At the regional scale, the results indicate that (i) the only factor that seems to be involved in the regional pattern is the identity of the study providing the data sets, which implies variability and bias in how research projects are carried out, from the sampling design through to data collection and analysis; (ii) the Cretan Na GISA sites may be considered as representative of the habitat in the Mediterranean, under certain conditions. [ABSTRACT FROM AUTHOR]

Arsenic is a widely distributed element in marine ecosystems. The main anthropogenic sources of this contaminant are domestic and industrial wastewaters, and since it can be harmful to humans even at low concentrations, it has been ranked as one of the top hazardous substances. Therefore, the analysis of arsenic is an essential task to assess the potential environmental and human health risk associated with sewage discharges. The accumulation of total arsenic on intertidal rocky shore macroalgae exposed to contaminated sewage discharges was measured in five macroalgae species ( Asparagopsis armata, Codium sp., Plocamium cartilagineum, Saccorhiza polyschides and Ulva sp.). Differences in the concentrations of arsenic were examined in the seawater and in the macroalgae species. The results showed significantly higher concentrations of arsenic near the sewage discharges in all the species except S. polyschides. Although the information obtained from total arsenic determination is not enough to assess the toxicological risk in the environment, this paper gives an important contribution on contamination risks and helps in choosing potential good biomonitors. [ABSTRACT FROM AUTHOR]

Macroalgal canopies are important ecosystem engineers, contributing to coastal productivity and supporting a rich assemblage of associated flora and fauna. However, they are often absent from infrastructures such as coastal defences and there has been a worldwide decline in their distribution in urbanised coastal areas. The macroalga Fucus spiralis is the only high-shore canopy forming species present in the Azores. It is widely distributed in the archipelago but is never found on coastal infrastructures. Here we evaluate factors that may potentially limit its establishment on artificial structures. A number of observational and manipulative experiments were used to test the hypotheses that: (i) limited-dispersal ability limits the colonisation of new plants onto artificial structures, (ii) vertical substratum slope negatively influences the survivorship of recruits, and (iii) vertical substratum slope also negatively influences the survivorship and fitness of adults. Results showed that the limited dispersal from adult plants may be a more important factor than slope in limiting the species ability to colonise coastal infrastructures, since the vertical substratum slope does not affect its fitness or survivorship. [ABSTRACT FROM AUTHOR]

It is known that rocky macroalgae distribution depends on several abiotic factors, but little attention has been given to geomorphological influences. This paper analysed the relation between geomorphological variables (active processes, coastal morphology, coastal orientation and lithology) and rocky intertidal macroalgae species at a local scale. Thirteen sites were sampled along the coast of Cantabria (North Spain) in order to obtain covers of macroalgae species. Multivariate analysis and logistic regression were applied, predicting the probability occurrence of macroalgae species as a response to the predictor geomorphological variables. Our results showed that coastal morphology and coastal orientation were the principal geomorphological factors explaining the structure of macroalgae communities. The most significant differences in substrate preferences were found between Bifurcaria bifurcata, that appears in wave-cut platforms oriented towards the east, and Corallina officinalis/Ellisolandia elongata and Gelidium spinosum , which are found in cliffs oriented towards the north and west. Although these variables help to characterise species distribution, their predictive value is still limited, possibly due to other factors influencing macroalgae. Thus, some of the geomorphological variables studied here are among the environmental factors that determined the distribution of intertidal macroalgae communities at a local scale, even if not always in a direct way. [ABSTRACT FROM AUTHOR]

Sewage discharges are among the most common anthropogenic stressors on rocky shores. However, studies on benthic invertebrates' responses to sewage pollution on insular assemblages are rare. In order to fulfil this gap, (i) the effects of sewage pollution and (ii) the recovery capacity of eulittoral insular assemblages were examined. The study was conducted on Terceira Island (Azorean Archipelago, Portugal), in four distinct areas: one impacted area (outfall in operation), one post-impacted area (decommissioned outfall) and two undisturbed reference areas. Results showed that the abundance of the dominant species changed between reference and impacted areas. More specifically, the abundance of limpets Patella candei, and barnacles Chthamalus stellatus decreased, while the abundance of littorinids Tectarius striatus and Melarhaphe neritoides increased near the sewage discharges. Seventeen months after removal of the outfall, limpet and barnacle populations had partially recovered, but littorinid populations had still not fully recovered. This study confirms the negative effects of sewage discharges on eulittoral assemblages, and provides information on the resilience of benthic species following the cessation of sewage disposal. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Biologia Marina y Oceanografía (RBMO) is the property of Universidad de Valparaiso, Facultad de Ciencias del Mar and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Peracarid crustaceans are an important component of the vagile fauna associated with coralline algal beds, which often characterize the infralittoral fringe of tropical rocky shores. Among other variables affecting faunal assemblages, sedimentation, food supply and oxygen concentration within mats or turfs of coralline algae may greatly depend on the exposure to waves. In this study, peracarid assemblages were compared at replicated rocky shores within different levels of wave exposure, along a coastline in south-eastern Brazil. Overall amphipod diversity (11 species) was much higher than tanaidacean diversity (two species). Correlation analyses did not support any biological interactions between amphipods and tanaidaceans. Habitat complexity, while apparently limiting amphipod populations, did not affect tanaidaceans at a local scale. Amphipod abundance, not assemblage structure, was positively affected by wave exposure, probably improving oxygen concentration levels and renewal of food resources. Rather than abundance, which remains fairly stable, exposure to waves determined species identity in tanaidaceans, with Zeuxo coralensis found at exposed shores and Leptochelia aff. dubia found at sheltered shores, except for two L. aff. dubia individuals found at one of the exposed sites. Differences in the supply of sediment and the ability of these species in manipulating grains for tube building may explain such a striking pattern. [ABSTRACT FROM PUBLISHER]

The Cystoseira ericaefolia group is conformed by three species: C . tamariscifolia , C . mediterranea and C . amentacea . These species are among the most important habitat forming species of the upper sublittoral rocky shores of the Mediterranean Sea and adjacent Atlantic coast. This species group is sensitive to human pressures and therefore is currently suffering important losses. This study aimed to assess the influence of anthropogenic pressures, oceanographic conditions and local spatial variability in assemblages dominated by C . ericaefolia in the Alboran Sea. The results showed the absence of significant effects of anthropogenic pressures or its interactions with environmental conditions in the Cystoseira assemblages. This fact was attributed to the high spatial variability, which is most probably masking the impact of anthropogenic pressures. The results also showed that most of the variability occurred on at local levels. A relevant spatial variability was observed at regional level, suggesting a key role of oceanographic features in these assemblages. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Oceanography is the property of Instituto Oceanografico da Universidade de Sao Paulo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The biogeographic border between the Eastern and the Atlantic subregions of the Lusitanian Province situated on the west coast of Asturias (N. of Spain) has moved westwards in recent years. A comparative study, consisting in a resurvey of 20 shores sampled in 1977, covering 200 km showed a large-scale change affecting the mid and low eulittoral. Cold-temperate canopy species such as kelps ( Laminaria hyperborea, Laminaria. ochroleuca and Saccorhiza polyschides ), fucoids ( Fucus serratus , Fucus vesiculosus and Himanthalia elongata ) and Chondrus crispus have almost disappeared and replaced by warm-temperate species such as Cystoseira baccata , Cystoseira tamariscifolia , Bifurcaria bifurcata and coralline algae ( Ellisolandia elongata , Lithophyllum incrustans and Mesophyllum lichenoides ). The loss of canopy-species can have consequences for the assemblage, especially in the case of fucoid-dominated assemblages. [ABSTRACT FROM AUTHOR]

Cinco especies de líquenes marinos son documentadas por primera vez en Chile: Arthopyrenia saxicola Massal., Caloplaca carphinea (Fr.) Jatta, C. thallincola (Wedd.) Du Rietz, Pertusaria rupicola (Fr.) Harm. y Xanthoria ectaneoides (Nyl.) Zahlbr. Dichos taxones fueron hallados en la Bahía de Constitución, Chile Central. Para cada taxón, se entrega una descripción basada en el material estudiado consistente en la morfología externa del talo y las características morfológicas internas de las estructuras reproductoras de cada especie. También se incluyen las reacciones químicas del talo y de algunas estructuras reproductoras, cuando el taxón lo amerita. Además se adjuntan fotografías a color de los talos de las especies estudiadasFive marine lichen species are reported for the first time in Chile: Arthopyrenia saxicola Massal., Caloplaca carphinea (Fr.) Jatta, C. thallincola (Wedd.) Du Rietz, Pertusaria rupicola (Fr.) Harm. and Xanthoria ectaenoides (Nyl.) Zahlbr. These were found at Bahía de Constitución, Central Chile. Descriptions of the material cover the external morphology of the thallus and the internal morphological characters of the reproductive structures. Colour photos of the thallus of all species are included, plus for some taxa we also describe chemical reactions of the thallus and of some reproductive structures

The canopy-forming brown macroalgae Fucus vesiculosus and Fucus radicans (Fucus) are the largest habitat-building species on rocky shores of the northern Baltic Sea. While their role on the diversity of invertebrate fauna is well documented, there is little information on their importance for the diversity of associated macroalgal species. We used comprehensive mapping data from the Finnish marine area (divided into four sea areas) to test the relationship between Fucus coverage and algal biodiversity (number of taxonomic units, Shannon-Wiener diversity index H′ and Pielou's evenness J'). To account for environmental variation, depth, wave exposure, Secchi depth and salinity were included as covariates. Examination of the algal communities highlighted a similar pool of taxonomic units across sea areas in shallow (0–4 m) rocky shores, with the two filamentous algal species Pylaiella littoralis and Ectocarpus siliculosus combined as one unit being the most common taxon. The Shannon-Wiener diversity index was highest in sites with Fucus coverage between 25% and 75%, while evenness increased with Fucus coverage. We did not detect any effects of Fucus coverage on the number of taxonomic units, which was rather affected by environmental parameters (depth, Secchi depth and salinity). The results show that Fucus , depending on its coverage, both competes with and facilitates the macroalgal community. Based on extensive data, we show how Fucus coverage relates to the diversity of the surrounding algal communities, further improving our understanding of factors that control biodiversity on shallow rocky shores in the northern Baltic Sea. • A relationships exists between Fucus coverage and the diversity of the algae in the northern Baltic Sea. • Algal diversity index changes in a non-linear way with increasing Fucus coverage. • Highest algal diversity is observed at intermediate values of Fucus coverage. • Most common algal taxa differ between areas along the Finnish coastline. [ABSTRACT FROM AUTHOR]

Coastal areas are under high human pressure, being affected by several sources of impacts, such as sewage effluents. Eulittoral assemblages of intertidal rocky shores are often exposed to sewage discharges. Such assemblages are accessible to sample, and their dominant species are easy to identify and widely distributed. These features make eulittoral assemblages potentially cost-effective in discerning between disturbed and undisturbed environmental conditions. In this study, a first attempt has been made to understand whether such assemblages are a suitable indicator of human impacts related to sewage discharges, able to consistently respond over large spatial scales. Sampling occurred in different environmental (sewage outfall and reference areas) and geographical locations (Atlantic insular, Atlantic mainland and Mediterranean). Multivariate analyses showed that the structure of eulittoral assemblages differed significantly between reference and impacted areas only on the Mediterranean shores. In all shores, limpet populations (genus Patella) appear to be affected by sewage discharge. The response of limpet populations differed between Atlantic and Mediterranean shores, probably due to within-species heterogeneities of ecological traits. Our results suggest that the response of limpets might be strictly context-dependent, thus limiting their potential to serve as general targets in monitoring the effects of sewage impact over large spatial scales.

The rocky inter-tidal habitat is a harsh and fluctuating environment, subject to frequent disturbances. Field observations of juvenile white seabream Diplodus sargus in inter-tidal rocky habitats were conducted to analyse the spatial distribution and feeding activity of this species in relation to the tidal cycle. The depth at which fish were observed did not change in most tidal phases while feeding activity changed with tidal level, showing the occurrence of tidal migrations and that feeding may be limited by habitat availability in shallow waters and thus be dependent on tidal changes. The present results show the exploitation of available feeding areas in the rocky inter-tidal by juvenile white seabream, which corroborates the importance of these habitats for the first developmental stages of this fish species. [ABSTRACT FROM AUTHOR]

Mussel beds and rockweed stands (fucoid algae) have been shown to be alternative states on rocky intertidal shores in New England, and here the hypothesis that variation in recruitment provides opportunity for the development of alternative community states was tested. Disturbance by ice scour opens patches for development of alternative states, and in winter 1996-1997, 60 experimental clearings of differing sizes were established on Swan's Island, Maine, USA. Half of the plots were re-cleared during the winter of 2010-2011. Recruitment data for barnacles, mussels, and fucoid algae collected from 1997 to 2012 were used to (1) test for persistence of scale-dependent thresholds, (2) estimate the magnitudes and sources of variation, (3) fit a surface of alternative states as defined by the cusp catastrophe, and (4) test if 1997 recruitment would predict 2010-2011 recruitment in re-scraped plots (i.e., a test of divergence, which is expected in systems with alternative states). For barnacles and mussels, recruitment varied enormously year to year and among sites, but showed consistent patterns over the long-term with respect to clearing size. Average recruitment prior to re-clearing was a good predictor of recruitment afterwards. In contrast, over 50% of the variance in fucoid recruitment was unexplained with weak effects among years and locations. Past fucoid recruitment was a poor predictor of subsequent recruitment. The cusp analysis indicated that fucoid recruitment defines the alternative states. Fucoid recruitment was largely unpredictable and suggests long-term, small-scale priority effects drive the development of alternative states. These observations strongly reinforce the notion that long-term and well-replicated experiments are necessary to develop robust tests of ecological theory. [ABSTRACT FROM AUTHOR]

Global seascapes are increasingly modified to support high levels of human activity in the coastal zone. Modifications include the addition of defense structures and boating infrastructure, such as seawalls and marinas that replace natural habitats. Artificial structures support different macrofaunal communities to those found on natural rocky shores; however, little is known about differences in microbial community structure or function in urban seascapes. Understanding how artificial constructions in marine environments influence microbial communities is important as these assemblages contribute to many basic ecological processes. In this study, the bacterial communities of intertidal biofilms were compared between artificial structures (seawalls) and natural habitats (rocky shores) within Sydney Harbour. Plots were cleared on each type of habitat at eight locations. After 3 weeks the newly formed biofilm was sampled and the 16S rRNA gene sequenced using the Illumina Miseq platform. To account for differences in orientation and substrate material between seawalls and rocky shores that might have influenced our survey, we also deployed recruitment blocks next to the habitats at all locations for 3 weeks and then sampled and sequenced their microbial communities. Intertidal bacterial community structure sampled from plots differed between seawalls and rocky shores, but when substrate material, age and orientation were kept constant (with recruitment blocks) then bacterial communities were similar in composition and structure among habitats. This suggests that changes in bacterial communities on seawalls are not related to environmental differences between locations, but may be related to other intrinsic factors that differ between the habitats such as orientation, complexity, or predation. This is one of the first comparisons of intertidal microbial communities on natural and artificial surfaces and illustrates substantial ecological differences with potential consequences for biofilm function and the recruitment of macrofauna. [ABSTRACT FROM AUTHOR]

A fundamental problem in ecology is to link spatial arrangements of key biota and the scale at which organisms interact with each other to structure communities and influence ecosystem functioning. Limpets are widely acknowledged to play an important role in the ecology of intertidal rocky shores and exert the strongest grazing effect of any marine grazer. As a consequence, to understand rocky shore dynamics it is necessary to understand the processes that control spatial and temporal patterns of limpet foraging. Much is known about how limpets behave and their distribution during low tide while at rest, and where and when limpets forage. However, it is less well understood how the behaviour and distribution of the same individuals within these two phases of activity can interact. At the smallest spatial scale, several species of limpet exhibit population-level biases in orientation during low tide. If orientation influences where and when limpets forage, this bias may lead to a directional bias in foraging direction and location during high tide, and potentially to patchy grazing. On the other hand, foraging location may determine low tide orientation. We tested these ideas by comparing the low tide orientation of individual limpets ( Cellana tramoserica ) with foraging frequency, and the relative direction of travel while foraging. We found that though there was an overall bias in departure angle and foraging location, there was no relationship between low tide orientation of individuals and their departure angle. Instead, prior to departure limpets rotated on their resting site to face a new direction. There was also no link between the direction of travel of limpets returning from foraging and their final low tide orientation, as limpets actively rotated on arrival at their resting site. Our findings suggest that there is little or no direct link between the orientation of an individual and its subsequent foraging, nor the converse. Limpets instead actively select both their orientation and the direction they depart for foraging by rotation on their resting site. These results decouple the small scale tide-out resting distribution and orientation of grazers from their ecological functioning. Therefore noting the location of limpets at low tide has limited use for predicting ecological consequences of their grazing. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Oceanography is the property of Instituto Oceanografico da Universidade de Sao Paulo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aim Isolation by distance ( IBD) analyses are an effective tool for determining genetic connectivity among populations, providing a basis for estimating dispersal and thus contributing to spatial biodiversity planning. Here, we use an IBD approach to determine patterns of connectivity to infer dispersal distances for a phylogenetically diverse range of marine species. Location Two thousand and eight hundred kilometre of South African coastline. Methods mt DNA data sets for 11 rocky shore and reef-dwelling marine species with diverse life history strategies (broadcast spawning, brooding and live-bearing) were used to quantify intraspecific genetic connectivity by means of global and pairwise Φst. Mantel tests were used to assess the significance of genetic structure with geographic distance. Significant, positive slopes were used to estimate dispersal distances. For all species, we also plotted genetic diversity along the coast and compared this to patterns of species richness. Results For seven of the 11 species tested, we report positive IBD relationships, with patterns of IBD of similar magnitude in broadcast spawners and live-bearers. Dispersal estimates were low, with effective distances of < 10 km per generation. We find discordance between pelagic larval development and population structure and that genetic structure and the physio-geographic features of the coastline considered to be important biogeographic barriers do not overlap. Genetic diversity and species richness show congruent patterns, with both variables lowest on the west coast, and increasing towards the east. Main conclusions Our study highlights the complexity of marine systems and the clear need for regional assessments of connectivity, rather than more general management plans which may not otherwise effectively encompass area-specific conservation needs. Importantly, we show that the current marine protected area ( MPA) network in South Africa is not effective in protecting evolutionary processes and strongly recommend a network of more closely spaced MPAs in the region that reflects the low average connectivity between distant marine populations. [ABSTRACT FROM AUTHOR]

To understand the impact of anthropogenically induced transformations of biological communities, their naturally occurring fluctuation must be recognized first. Therefore, the aim of this study was to investigate the variability in Antarctic intertidal benthic assemblage faunal composition during an annual cycle (King George Island 62° S). Once a month, from December 2016 to November 2017, samples were collected at low-, mid- and high-tidal levels. Polychaetes were the most speciose group (15 species), followed by amphipods (12). Throughout the year, the most numerous taxa were gastropods (38% of the total number), followed by amphipods (23%) and bivalves (22%). The general pattern of the number of species and their abundance and biomass depended on the season and exhibited the highest values in austral autumn (April–June). Both species richness and abundance were highest in June and lowest in August. This study discovered that Antarctic intertidal macrofauna assemblages quickly respond to changes in environmental conditions and thus reflect seasonal climate fluctuations. The rapid development of these assemblages when the conditions are favourable proves their opportunistic and highly adaptable nature, which is potentially a good prognosis for survival in this ever-changing ecosystem. • Intertidal macrofauna is dominated by gastropods, followed by amphipods and bivalves. • Intertidal assemblages decrease in abundance from lower to higher tidal levels. • In autumn, the intertidal macrofauna was the most diverse and abundant. • Antarctic intertidal fauna quickly respond to natural environmental fluctuations. • The dominant species year around are also most abundant at higher tidal levels. [ABSTRACT FROM AUTHOR]

Contamination is a particular harmful type of chemical disturbance and predicting their effects on natural systems is very complex. Effects of disturbances vary in space and time and depend, among other things, on the type and age of organisms, the habitat being studied and the complex interactions occurring in the systems. Most impact analyses of contaminants are however still done with limited number of selected organisms under laboratory conditions. Manipulative experiments done in situ are important to measure ecologically relevant responses of contaminant effects on marine systems. Ecological approaches on contamination studies, accounting for interactions among species and the environment are essential to understand how such disturbances affect systems. We evaluated the effects of bleach and permethrin, two common and pervasive contaminants, on intertidal benthic assemblages in two different successional stages, mature and young. There were no impacts on the overall structure of assemblages, regardless of their age. The lack of effects on the structure of assemblages might be due to the intrinsic characteristic of the habitat studied, which provide few sinks for contaminants, as well as the inherent features of the organisms themselves. Bleach did cause, however, a decrease in the abundance of limpets, which can have further consequences to these systems. This study shows the importance of studies on chemical disturbances done under relevant natural scenarios and that efficient management policies of natural systems will only achieve successful responses with properly designed experiments under natural conditions. [ABSTRACT FROM AUTHOR]

Negative responses of infauna close to rocky substrates are well known to subtidal bottoms, but there are few studies addressing similar intertidal habitats. We tested the hypothesis that the proximity to rocky shores negatively affects the density and richness of intertidal infauna of tidal flats by assessing infaunal variation across the increasing distances from rocky shores in two tidal flats (Pasto and Limoeiro) of a subtropical estuary in southern Brazil. Total density decreased significantly with the proximity to rocks only in Pasto due to density variations in the two numerically dominant species, the bivalve Anomalocardia flexuosa and the polychaete Armandia hossfeldi. Richness decreased significantly with the proximity to the rocky shores only in Limoeiro. Multivariate analyses revealed significant differences in species and functional groups composition between assemblages near and far from the rocky shores. Assemblage variability patterns were mostly explained by sediment variables. Our hypothesis was partially refuted because negative effects on the infauna were spatially inconsistent, due to differences in species composition between tidal flats, and to distinct responses of individual taxa. Even with the absence of consistent response patterns, the proximity to the rocky shores emerged as a relevant structuring factor of the surrounding intertidal infauna. [ABSTRACT FROM AUTHOR]

The gastropod Trophon geversianus exhibits shell polymorphisms along its distribution in subtidal and intertidal habitats. Our hypothesis is that morphological and behavioral patterns of T. geversianus represent habitat-specific constrains; subsequently we expect an association between shell morphology, attachment behavior, and habitat. In order to test this hypothesis we compared individuals from intertidal and subtidal habitats, at three sites in Golfo Nuevo (Argentina). We analyzed shell morphology using classic morphometric variables, 3D geometric morphometrics and computing tomography scan. The results were complemented with field observations of attachment to substrate and turning time behavior, as well as of the number of shell scars produced by crab predation. Our results showed differences in shell size and shape between intertidal and subtidal-collected individuals. Centroid size, total weight and shell weight, as well as shell density and thickness were significantly lower in intertidal individuals than in subtidal ones. Gastropods from intertidal habitats presented a low-spired shell and an expanded aperture which might allow better attachment to the bottom substrate, while subtidal individuals presented a slender and narrower shell shape. The number of crab scars was significantly higher in shells from subtidal individuals. Observations of the behavior of gastropods placed at the intertidal splash zone showed 100% of attachment to the bottom in the intertidal individuals, while subtidal specimens only attached in average in 32% of the cases. These latter took 12 times longer to re-attach to the bottom when faced up. Phylogenetic analysis of COI gene fragments showed no consistent differences among individuals sampled in both habitats. All these results suggest that T. geversianus has developed two ecomorphs with distinct morphological and behavioral responses to physically stressful conditions registered in north Patagonian intertidals, as opposed to lower physical stress but higher predation pressure in the subtidal habitats. The findings of this work constitute a starting point in the study of ecological adaptation processes in gastropods from Patagonian coastal environments. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Oceanography is the property of Instituto Oceanografico da Universidade de Sao Paulo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The search for cost-effective indicators able to detect anthropogenic impacts is an essential prerequisite to plan mitigation interventions, which can prevent further deterioration of coastal areas. Eulittoral assemblages are accessible for sampling, and their dominant species are easy to identify and widely distributed. This study assessed the potential of eulittoral assemblages to reflect environmental perturbations related to sewage discharge across different environmental and geographical locations. Sampling occurred in impacted (near sewage discharge) and control areas, on both Atlantic and Mediterranean shores. Multivariate analyses showed that the structure of eulittoral invertebrate assemblages differed significantly between control and impacted areas for the Mediterranean, but not for the Atlantic case study. Macroalgae responses to sewage discharge were found on the Mediterranean shore with a significantly higher abundance of Chlorophyta near the outfall. Limpet populations of the genusPatellaappear to be affected by sewage discharge. The response of limpet populations differed between Atlantic and Mediterranean shores, probably due to among-species differences of ecological traits. Our results suggest that the response of eulittoral assemblages and limpets to sewage discharge might be strictly context-dependent, thus limiting their potential to serve as general indicators in monitoring the effects of this source of human impact over large spatial scales. [ABSTRACT FROM AUTHOR]

The consequences of biodiversity loss in the face of environmental change remain difficult to predict, given the complexity of interactions among species and the context-dependency of their functional roles within ecosystems. Predictions may be enhanced by studies testing how the interactive effects of species loss from different functional groups vary with important environmental drivers. On rocky shores, limpets and barnacles are recognised as key grazers and ecosystem engineers, respectively. Despite the large body of research examining the combined effects of limpet and barnacle removal, it is unclear how their relative importance varies according to wave exposure, which is a dominant force structuring intertidal communities. We tested the responses of algal communities to the removal of limpets and barnacles on three sheltered and three wave-exposed rocky shores on the north coast of Ireland. Limpet removal resulted in a relative increase in microalgal biomass on a single sheltered shore only, but led to the enhanced accumulation of ephemeral macroalgae on two sheltered shores and one exposed shore. On average, independently of wave exposure or shore, ephemeral macroalgae increased in response to limpet removal, but only when barnacles were removed. On two sheltered shores and one exposed shore, however, barnacles facilitated the establishment of fucoid macroalgae following limpet removal. Therefore, at the scale of this study, variability among individual shores was more important than wave exposure per se in determining the effect of limpet removal and its interaction with that of barnacles. Overall, these findings demonstrate that the interactive effects of losing key species from different functional groups may not vary predictably according to dominant environmental factors. [ABSTRACT FROM AUTHOR]

Scientists recognize the importance of ecological data prior to invasion by non-native species in order to evaluate changes in the recipient community. Here we assess the potential impact of the invasion of the bivalve Isognomon bicolor (C.B. Adams, 1845) on Brazilian rocky shores through the use of surveys both before and after the arrival of this non-native species. The invader was mostly distributed across the mid and low shore levels of the intertidal zone with relative abundance ranging from 9.0 to 36.7 percent cover. The mid shore, previously dominated by the native barnacle Tetraclita stalactifera (Lamarck, 1818), was co-dominated by this barnacle species and I. bicolor after invasion. The relative abundance of these species, and presumably the interaction strength between them, differed between sites. At the site where I. bicolor reached the highest abundance (around 30% on average), the abundance of T. stalactifera decreased on average 70% compared to baseline values obtained before the I. bicolor invasion. Finally, conspicuous and extensive I. bicolor beds such as those observed in this study have not been reported in its original distribution range. Beds of I. bicolor may create a much more intricate biogenic matrix than the extents of bare rock and barnacle clumps it replaced. This bivalve may act as an ecosystem engineer and, thus a functionally different component of the intertidal community in its invaded range compared to its native distribution. [ABSTRACT FROM AUTHOR]

The impact of herbivores on primary producers in differing oceanographic regimes is a matter of intense ecological interest due to ongoing changes in their abundance, that of their predators, and anthropomorphic alteration of nutrient cycles and climatic patterns. Interactions between productivity and herbivory in marine habitats have been studied on temperate rocky shores, coral reefs, mangroves, and salt marshes, but less so at tropical latitudes. To determine how herbivore-alga dynamics varied with oceanographic regime, we used the comparative-experimental approach in rocky intertidal communities on the Galápagos Islands from January 2006 to January 2009. This setting was selected because strongly contrasting oceanographic conditions occurred within a range of ∼181 km, with significant differences in temperature, nutrients, phytoplankton productivity, and intertidal communities, and in abundance of macro-herbivores, including marine iguanas. Experiments and measurements were conducted at two sites in each of three oceanographic regimes characterized by low, intermediate, and high bottom-up inputs. At sites of low inputs, macroherbivores (fish, crabs, iguanas) had a consistent top-down effect, reducing algal abundance, and leaving a few grazer-resistant varieties. At sites of intermediate and high inputs, consumer impacts were stronger during La Niña (cool phase) than during El Niño (warm phase). At sites of high inputs, algal biomass was naturally relatively high and was dominated by the edible algae Ulva spp. Macro-grazers reduced algal biomass, but their primary effect was indirect, as articulated corallines displaced other species of algae in their absence. Prior results from the tropics had revealed dominant effects of top-down interactions and recruitment in structuring intertidal communities. Our results suggest that, when a broader oceanographic scenario is taken into account, the relative importance of top-down and bottom-up forces are context dependent, varying with oceanographic regime and climatic variability. [ABSTRACT FROM AUTHOR]

The benthic community on the rocky foreshore of Guéthary (France) has been monitored since 2002. The standardized and quantitative monitoring method counts 20 geographically referenced quadrats spread on three littoral zones: upper mediolittoral, lower mediolittoral and infralittoral zones. The setting up of this monitoring occurred when the “Prestige” sunk close to the Finistere Cape in Galicia (Spain). The oil slick following the shipwreck impacted the Guéthary foreshore in early 2003. After the “Prestige” oil spill, the taxonomic richness decreased in the studied area with a loss of 16 species – from 57 in 2002 (before the shipwreck) to 41 species in 2004. Two or 3 years later, taxonomic richness increased to a level observed prior to the oil spill. Along the years, temporal variations in community structure of benthic macrofauna are revealed by detailed analysis. Some polluo-sensitive species disappeared after 2002 and have not reappeared yet ( e.g. : Hymeniacidon perlevis ). Some others reappeared two or three years after the spill or even later ( e.g. : Amphipholis squamata , Botryllus schlosseri , Calliostoma zizyphinum , Echinus esculentus , etc. ). Noteworthy changes were found in 2004 driven by the sudden increase in abundance of grazers. The following years, these abundances went back to a stable level. The benthic community seemed to recover almost 5 years later, although a new composition of macrofauna populations was observed. In overall aspect, the complexity of the benthic ecosystem response to oil spills confirms the need of regularly updated baselines to assess the impact of pollutions and more generally to maintain marine biodiversity. [ABSTRACT FROM AUTHOR]

Macroalgae comprise a prominent part of the rocky benthos where many invertebrates develop, and are believed to be undergoing severe declines worldwide. In order to investigate how the vegetation structure (crustose, basal and canopy layers) contributes to the diversity, structure and function of benthic invertebrates, a total of 31 subtidal transects were sampled along the northeast Atlantic coast of Spain. Significant positive relationships were found between the canopy layer and faunal abundance, taxonomic diversity and functional group diversity. Canopy forming algae were also related to epiphytic invertebrates, medium size forms, colonial strategy and suspensivores. By contrast, basal algae showed negative relationships with all variables tested except for detritivores. Multivariate multiple regression analyses (DISTLM) point to crustose as well as canopy layers as the best link between seaweeds and invertebrate assemblage structure. A close relationship was found between taxonomic and functional diversities. In general, low levels of taxonomic redundancy were detected for functional groups correlated with vegetation structure. A conceptual model based on the results is proposed, describing distinct stages of invertebrate assemblages in relation to the vertical structure of vegetation. [ABSTRACT FROM AUTHOR]