Las comunidades meiobentónicas en playas arenosas expuestas de la costa gallega (NO España), seis meses después del vertido de fuel del Prestige: importancia de los hidrocarburos aromáticos policíclicos (HAPs)

The effect of polycyclic aromatic hydrocarbons (PAHs) on Galician sandy beach ecosystems, six months after the Prestige oil spill, was evaluated using the meiobenthos at a higher taxon level as an indicator. Meiobenthos community structure, environmental variables and sediment PAH content from six affected exposed beaches were studied and compared with three reference sites. They were also compared with data from polluted beaches obtained during the first days of the spill. Significant amounts of PAHs were found in affected beach sediments and both univariate and multivariate analyses showed differences between affected and reference beaches. Correlation analyses between PAH content and the meiobenthos community structure showed that 1,2-dimethylnaphthalene (C2-NAPH) and 1-methylphenanthrene (C-PHEN) affected both the community structure and the abundance of the main taxa. These two PAHs seem to be responsible for the low meiofauna density values, which suggests that there is a relationship between the oil spill and the differences between affected and reference localities.Este trabajo tiene como objetivo evaluar el efecto de los hidrocarburos aromáticos policíclicos (HAPs) en playas arenosas gallegas, seis meses después del vertido de fuel producido por el Prestige, utilizando el meiobentos a nivel de los grandes grupos zoológicos. Para llevar a cabo esta evaluación la comunidad meiobentónica, variables ambientales y el contenido en HAPs del sedimento fueron estudiados en seis playas intermareales afectadas y comparados con tres localidades de referencia. También fueron comparados con datos de playas contaminadas obtenidos durante los primeros días del derrame. Considerables cantidades de HAPs fueron encontradas en los sedimentos de las playas afectadas y tanto los análisis univariantes como los multivariantes indicaron diferencias entre las playas afectadas y las de referencia. Los análisis de correlación entre el contenido en HAPs y la estructura de la comunidad meiobentónica indicaron que el 1, 2-dimetilnaftaleno (C2-NAPH) y el 1-metilfenantreno (C-PHEN) jugaban un papel importante tanto en la estructura de la comunidad como en la abundancia de los principales taxones. Estos dos HAPs parecieron ser los responsables de las bajas densidades de meiofauna, corroborando la relación entre el vertido de fuel y las diferencias entre las localidades afectadas y de referencia

Influence of urbanization on patterns of variability of Mytilus galloprovincialis populations

Urbanization is currently one of the most widespread disturbances urgently requiring empirical data regarding its effects on coastal ecosystems. The aim of this study was to compare patterns of variability in populations of the Mediterranean mussel, Mytilus galloprovincialis, between urban and non-urban intertidal rocky shores, over a temporal scale of 12 months and multiple spatial scales (from cm to 10 s of km). For this, variance components associated with percentage cover, spat and total density, condition index, shell length and clump thickness of mussels were compared. Different patterns emerged depending on the response variable and the spatial and temporal scale. There was in general, a higher variability in urban than in non-urban shores, particularly for shell length, spat and total density that can be interpretated as a first stage of degradation, before noticing changes in mean values of these variables. Moreover, the most relevant scales of variability of total and spat density changed with urbanization (10 s of km in urban; 10 s of cm/m in non-urban). Results highlight the need for adopting proper management plans that should include the relevant spatial and temporal scales of variability; otherwise, they will fail in ameliorating urbanization effects on intertidal ecosystem

Short-term effects of trampling on intertidal Mytilus galloprovincialis beds

Human trampling represents one of the main anthropogenic pressures in the rocky intertidal. This habitat includes many ecosystem engineers such as mussels that provide biogenic habitat and multiple services. This research assessed potential impacts of human trampling on beds of the mussel, Mytilus galloprovincialis, on NW shores of Portugal. To test for direct effects of trampling on mussels and indirect effects on the associated assemblages, three treatments were applied: control (untouched beds), low and high intensity of trampling. Effects of trampling were dependent on the taxa. Thus, values of shell length of M. galloprovincialis were greater under the highest intensity of trampling while abundances of Arthropoda, Mollusca and Lasaea rubra showed the opposite pattern. Moreover, total number of taxa and abundances of Nematoda and Annelida showed higher values under low trampling intensity. The implications of these results to manage human use in areas with ecosystem engineers are discusse

Las comunidades meiobentónicas en playas arenosas expuestas de la costa gallega (NO España), seis meses después del vertido de fuel del Prestige: importancia de los hidrocarburos aromáticos policíclicos (HAPs

The effect of polycyclic aromatic hydrocarbons (PAHs) on Galician sandy beach ecosystems, six months after the Prestige oil spill, was evaluated using the meiobenthos at a higher taxon level as an indicator. Meiobenthos community structure, environmental variables and sediment PAH content from six affected exposed beaches were studied and compared with three reference sites. They were also compared with data from polluted beaches obtained during the first days of the spill. Significant amounts of PAHs were found in affected beach sediments and both univariate and multivariate analyses showed differences between affected and reference beaches. Correlation analyses between PAH content and the meiobenthos community structure showed that 1,2-dimethylnaphthalene (C2-NAPH) and 1-methylphenanthrene (C-PHEN) affected both the community structure and the abundance of the main taxa. These two PAHs seem to be responsible for the low meiofauna density values, which suggests that there is a relationship between the oil spill and the differences between affected and reference localities– Este trabajo tiene como objetivo evaluar el efecto de los hidrocarburos aromáticos policíclicos (HAPs) en playas arenosas gallegas, seis meses después del vertido de fuel producido por el Prestige, utilizando el meiobentos a nivel de los grandes grupos zoológicos. Para llevar a cabo esta evaluación la comunidad meiobentónica, variables ambientales y el contenido en HAPs del sedimento fueron estudiados en seis playas intermareales afectadas y comparados con tres localidades de referencia. También fueron comparados con datos de playas contaminadas obtenidos durante los primeros días del derrame. Considerables cantidades de HAPs fueron encontradas en los sedimentos de las playas afectadas y tanto los análisis univariantes como los multivariantes indicaron diferencias entre las playas afectadas y las de referencia. Los análisis de correlación entre el contenido en HAPs y la estructura de la comunidad meiobentónica indicaron que el 1, 2-dimetilnaftaleno (C2-NAPH) y el 1-metilfenantreno (C-PHEN) jugaban un papel importante tanto en la estructura de la comunidad como en la abundancia de los principales taxones. Estos dos HAPs parecieron ser los responsables de las bajas densidades de meiofauna, corroborando la relación entre el vertido de fuel y las diferencias entre las localidades afectadas y de referenciaThis research was supported by the Ministerio de Ciencia y Tecnología (Programa Nacional: Acción urgente Prestige-Recursos Naturales)S

Effects of habitat homogenisation on assemblages associated with mussel clumps

Biodiversity loss is considered one of the main threats to marine ecosystems. In this framework of biodiversity decline, organisms that provide biogenic habitat play a relevant role by their capacity to structure assemblages and influence ecological processes. The Mediterranean mussel Mytilus galloprovincialis is considered an ecosystem engineer because it alters local environmental conditions maintaining habitat suitability for other organisms, and enhancing local biodiversity. Although it is widely recognized that mussel beds increase diversity, the drivers shaping these assemblages are poorly explored. We investigate whether mussel size homogenisation shapes the abundance, richness and structure of macrobenthic assemblages associated with mussel beds in two shores of the Galician coast (NW Spain). At each shore, two sites, 10 m apart, were selected and at each site, faunal assemblages were compared between mussel clumps showing shells of various sizes (control), and mussel clumps with closely similar-sized mussels, considered as homogenised. Homogenised clumps showed, in general, higher values in total number of individuals and species than control clumps. Regarding the effect of mussel size homogenisation on the multivariate structure of the assemblages, significant differences between control and homogenised clumps were found in three out of the four sites. Most relevant associated species usually reached higher abundances in homogenised clumps than control ones. Therefore, mussel size homogenisation influenced the structure of the macrofaunal assemblages associated with mussel beds but, its effect was context dependent (i.e., varied with sites). Information about the species contribution to dissimilarities among homogenised and control clumps was provided and the potential influence of sediment and algae on mussel clumps was discusse

A review of coastal anthropogenic impacts on mytilid mussel beds: Effects on mussels and their associated assemblages

Mussel beds are an important habitat in many coastal systems, harboring a high diversity of biota. They are threatened by anthropogenic impacts that affect mussels and their associated assemblages. Pollution, harvesting, trampling, dredging and trawling are major threats faced by these communities. Most of the studies on the effects of such impacts on the mussel beds overlook the associated fauna. Since mussels are very resilient, especially to pollution, the associated fauna can provide a better footprint of the impacts’ effects. In this review, we looked into the main remarks regarding the effects of anthropogenic impacts in mussel bed communities. Organic pollution was the best studied impact and the Atlantic region was the best studied zone. Low values of abundance, biomass, diversity, evenness and species richness were reported for all categories of impacts, with some studies describing declines in at least three of these descriptors. Among the associated fauna, some tolerant species benefited from the impacts, particularly organic enrichment, and became more abundant, but sensitive species suffered considerable declines in density, mainly in dredging and trawling impacts. Therefore, fauna associated with mussel beds is a suitable indicator of anthropogenic disturbance

Recent changes on the abundance and distribution of non-indigenous macroalgae along the southwest coast of the Bay of Biscay

Twenty-three rocky shores along approximately 225 km on the southwest coast of the Bay of Biscay were sampled during the springs of 2014 and 2021, to explore changes in the distribution and abundance of four non-indigenous species (NIS) macroalgae (i.e., Asparagopsis armata, Grateloupia turuturu, Sargassum muticum, and Undaria pinnatifida) by using a semi-quantitative scale. Results showed relevant changes in the distribution and abundance of NIS. The kelp U. pinnatifida was recorded in 2021 for the first time on two shores. The distribution of G. turuturu showed an extension in its range of distribution of 200 km to the east. The other two target species S. muticum and A. armata were widely distributed along the whole 225 km of the studied area in 2014 and 2021, with higher abundance in 2021. Therefore, we strongly advise the necessity of future monitoring programs for these four NIS species. These monitoring programs will explore the progress of invasion and resilience of native species.This study was supported by the project ATLANTIDA (ref. NORTE-01-0145-FEDER-000040), supported by the Norte Portugal Regional Operational Program (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement and through the European Regional Development Fund (ERDF). This study was supported by the FCT-Foundation for Science and Technology through national funds within the scope of Contrato-Programa” UIDB/04050/2020 funded by national funds through the FCT I.P and, UIDB/04423/2020, UIDP/04423/2020. L. Guerrero-Meseguer was financed thanks to a grant from the Department of European Funds, University, and Culture of the Government of the Balearic Islands. P. Veiga was hired through the Regulamento do Emprego Científico e Tecnológico-RJEC from the Portuguese Foundation for Science and Technology (FCT) program (CEECIND/03893/2018)

Spatial-temporal variability of Mytilus galloprovincialis Lamarck 1819 populations and their accumulated sediment in northern Portugal

Mytilus galloprovincialis is an ecosystem engineer that provides habitat and generates environmental heterogeneity, increasing local biodiversity. Moreover, it is an economically important species representing 14% of the global production of marine bivalves. Natural drivers and the increase of anthropogenic pressures, such as sediment stress, influence its populations on rocky shores. The objective of this study was to explore the spatial-temporal patterns of different M. galloprovincialis attributes along the north of Portugal. For that purpose, six rocky shores were selected and sampled six times along the year 2019. The percentage of cover, density, spat density, condition index, clump thickness, size classes and clump sediment content were considered. Results showed the lack of seasonality in M. galloprovincialis along the north coast of Portugal. However, density, spat stage, clump thickness, condition index and size classes showed some variability among dates and shores. The percentage cover and sediment content only significantly differed among shores. Our results indicated an absence of seasonality for all the studied variables, probably because temperature was always within the optimum range for this species and the abundance of food supply in the study area independently of the season. The accumulated sediment on mussel clumps did not show any temporal variability with only significant differences among shores. The accumulated sediment was composed mainly by medium and coarse sand and it was correlated with mussel average size, condition index, but especially with the mussel clump thickness

Estudio preliminar del efecto del fuel sobre la meiofauna de algunas playas gallegas, en los primeros días de la marea negra del Prestige

Con el objetivo de obtener una primera evaluación urgente del efecto de la marea negra provocada por el Prestige, hemos estudiado la meiofauna de varias playas gallegas en los días siguientes al accidente. Como parámetros poblacionales para el estudio de dichas comunidades hemos considerado la abundancia, la densidad, la heterogeneidad faunística y el índice Nematodos/Copépodos Harpacticoideos. En ninguna de las playas la meiofauna se vió totalmente eliminada. La densidad oscila entre 4 individuos/100 cc (Malpica) y 663 individuos/100 cc. (Lira) y la heterogeneidad faunística entre 2 taxones (Baldaio) y 8 taxones (Lariño, Lira). Las comunidades están dominadas por los Nematodos, los Copépodos Harpacticoideos o por una combinación de diferentes taxones