Uso de diseños jerárquicos en la detección de escalas de heterogeneidad en la especie invasora Sargassum muticum

Invasion of alien species poses serious threats to many ecosystems. Despite the potential of Sargassum muticum to spread and invade new areas, no attention has been given to the study of variability of structural or morphological features across different spatial scales. We employed a hierarchical sampling design to examine patterns of spatial variability of fertility and morphological variables of S. muticum over different spatial scales (quadrats, sites, locations, rias) ranging from metres to tens of kilometres We repeated the sampling in March, April and July to test for the consistency of patterns through time. There was no variability between rias (tens of kilometres apart), but substantial differences occurred at the other scales examined. Fertility and percent cover varied between locations (1.5-3 km apart), whereas morphological variables varied between sites (tens of metres apart) and quadrats (metres apart). Furthermore, patterns of variation were not consistent over time. The study demonstrated the importance of a multi-scale sampling programme for monitoring seaweed invasion.Las especies invasoras representan una seria amenaza para muchos ecosistemas. A pesar del potencial de Sargassum muticum para extenderse e invadir nuevas áreas, no se ha dedicado ninguna atención al estudio de la variabilidad de las características estructurales o morfológicas a diferentes escalas espaciales. Hemos usado un diseño de muestreo jerárquico para examinar patrones de variabilidad espacial de las variables fenológicas y morfológicas de S. muticum a diferentes escalas espaciales (cuadrantes, sitios, localidades, rías) que van desde unos pocos metros a decenas de kilómetros. Repetimos el muestreo en marzo, abril y julio para comprobar la consistencia de los patrones a lo largo del tiempo. No hubo variabilidad entre rías (decenas de kilómetros de separación), pero se encontraron diferencias sustanciales a otras escalas. La fertilidad y el porcentaje de cobertura variaron entre localidades (1.5-3 km) y tiempo, mientras que las variables morfológicas variaron entre sitios (decenas de metros) y cuadrantes (metros). Asimismo, los patrones de variabilidad no fueron consistentes en el tiempo. El estudio demostró la importancia de los programas de muestreo utilizando múltiples escalas espaciales para el seguimiento de algas invasoras

Semantic segmentation of major macroalgae in coastal environments using high-resolution ground imagery and deep learning

Macroalgae are a fundamental component of coastal ecosystems and play a key role in shaping community structure and functioning. Macroalgae are currently threatened by diverse stressors, particularly climate change and invasive species, but they do not all respond in the same way to the stressors. Effective methods of collecting qualitative and quantitative information are essential to enable better, more efficient management of macroalgae. Acquisition of high-resolution images, in which macroalgae can be distinguished on the basis of their texture and colour, and the automated processing of these images are thus essential. Although ground images are useful, labelling is tedious. This study focuses on the semantic segmentation of five macroalgal species in high-resolution ground images taken in 0.5 x 0.5 m quadrats placed along an intertidal rocky shore at low tide. The target species, Bifurcaria bifurcata, Cystoseira tamariscifolia, Sargassum muticum, Sacchoriza polyschides and Codium spp., which predominate on intertidal shores, belong to different morpho-functional groups. The study explains how to convert vector-labelled data to raster-labelled data for adaptation to convolutional neural network (CNN) input. Three CNNs (MobileNetV2, Resnet18, Xception) were compared, and ResNet18 yielded the highest accuracy (91.9%). The macroalgae were correctly segmented, and the main confusion occurred at the borders between different macroalgal species, a problem derived from labelling errors. In addition, the interior and exterior of the quadrats were correctly delimited by the CNNs. The results were obtained from only one hundred labelled images and can be performed on personal computers, without the need to resort to external servers. The proposed method helps automation of the labelling process.SIFundación Biodiversidad, the Ministerio para la Transición Ecológica y 383 el Reto Demográfico through the Pleamar program, co-funded by the European Maritime and Fisheries Fund (EMFF), call 2018; and Xunta de Galicia for human resources and competitive reference groupsFundación Biodiversidad, the Ministerio para la Transición Ecológica y 383 el Reto Demográfico through the Pleamar program, co-funded by the European Maritime and Fisheries Fund (EMFF), call 2018; and Xunta de Galicia for human resources and competitive reference groupsMinisterio de Ciencia, Innovación y Universidades -Gobierno de Españ

Monitoring and mapping of intertidal macroalgae using low-cost geospatial automated techniques

The global extent of macroalgae is declining with important consequences on marine biodiversity and ecosystem processes. Tracking the status and trends of macroalgal cover is, therefore, an emerging priority for ocean and coastal management. A remote sensing technique combining UAVs surveys with in situ data acquisition was developed to map intertidal macroalgae from rocky shores in a marine protected area, the Atlantic Islands of Galicia National Park (Illas Cíes, NW Spain). The classifcation by groups (brown and green macroalgae) achieved a good precision. A more precise classifcation would be achieved by focusing on those spectral bands where the highest diferences between species appeared.Peer Reviewe

Loss of surficial sedimentary carbon stocks in seagrass meadows subjected to intensive clam harvesting

Seagrass carbon stocks are vulnerable to physical disturbance. We assessed the effect of clam harvesting on the organic carbon (Corg) stocks in surface sediments in four intertidal Zostera noltei meadows on the Iberian Atlantic coast (Spain and Portugal), by comparing undisturbed and harvested areas. We also monitored the spatial cover of the meadows throughout the growing season. Sedimentary Corg content and Corg stocks were about four times lower in intensively harvested areas than in control areas, but there were not differences between areas with low harvesting pressure and control areas. Reductions of 53–85% in sedimentary Corg stocks of Z. noltei meadows were caused by intensive clam harvesting. The effect of intensive clam harvesting on Corg stocks increased throughout the growing season, but the area covered by the seagrass increased from 21 to 37%, suggesting rapid recovery of seagrass canopies and potential recovery of sedimentary Corg stocks.info:eu-repo/semantics/publishedVersio

Sandy beaches as biogeochemical hotspots : the metabolic role of macroalgal wrack on low-productive shores

Sandy beaches, which represent the most common type of land-sea interface, harbor distinctive biotic communities and regulate the flow of energy between marine and terrestrial ecosystems. Accumulations of sea wrack on sandy beaches are of crucial importance for recycling beach nutrients and for regulating trophic connectivity and coastal functioning. We investigated the role of beaches as biogeochemical hotspots by examining the metabolic activity in accumulations of different species of wrack on two exposed beaches affected by different levels of human pressure. Experimental wrack patches provided large amounts of different sedimentary nutrients over time due to remineralization of the algae. Unsurprisingly, the variation in the nutrients present in the beach sediments was related to the species of wrack considered. Macroalgal wrack was metabolically very active and supported high respiration rates represented by intense CO2 fluxes. Importantly, we demonstrated that the wrack metabolic rate differed significantly depending on the algal species considered. Different macrofauna and bacterial assemblages were identified in the different wrack patches and on the different beaches. We suggest that human activities such as beach grooming can modify the wrack-associated communities, thus contributing to the variability in the biogeochemical processes and metabolic rates. Significant changes in the type and amount of wrack deposited on beaches can change fundamental processes related to the marine-terrestrial transfer of nutrients and energy and to the marine-atmospheric transfer of CO2 emissions, with ecological consequences for nearshore environments.Peer reviewe

Mapping invasive macroalgae in the Western Iberian Peninsula: a methodological guide

info:eu-repo/semantics/publishedVersio

Mussel Shells from Marine Aquaculture Act like Ecosystem Engineers: Legacy Effects on Benthic Communities

Ecosystem engineers are organisms that cause changes in the physical state of biotic and abiotic structures that modulate the availability of resources to other species, thus affecting biochemical cycles. Molluscs, especially bivalves such as mussels, are widespread in coastal environments and they are excellent ecosystem engineers because of the durability of their shells, which add complexity and heterogeneity to benthic environments. The presence of mussel farms favours the accumulation of shells in benthic environments and may influence surrounding bare sediments, with potential legacy effects on benthic communities. We studied the effects of the accumulation of mussel shells at finfish farms and mussel farms by experimentally comparing bare sediment and sediment with fragmented shells in terms of the abundance of the most relevant faunal groups, specifically polychaete families as well as physical–chemical variables in sediment water samples, specifically organic matter (OM), redox potential, and acid-volatile sulphides (AVS) NH4+ and PO43−. The experiment was replicated under two environmental conditions over a period of 35 days: eutrophic muddy sediments and oligotrophic sandy sediments. The OM and AVS values were significantly higher in the eutrophic sediment with mussel shells. Only NH4+ was positively affected by the mussel shells in the oligotrophic conditions. Differences between the two environments were observed, and the effect of the mussel shells on the polychaete assemblages was more significant in the oligotrophic conditions. Mussel shell accumulations affected the structure of benthic assemblages by modifying their heterogeneity and complexity, which suggests that the presence of mussel farms above bare sediment may affect ecosystem functioning. Aquaculture has potentially negative or positive effects that must be addressed on a large scale, considering the increased input of organic matter and also the simultaneous presence of mussel shell waste, both of which alter the surrounding environment. This is particularly important in oligotrophic sandy sediment.This research was funded by the project CGL2015-70136-R from the Spanish National Agency for Research (MINECO/FEDER)

Will climate change compromise the thermal comfort areas of socio-economically important bivalve species in the Rías Baixas (NW Spain)?

Ponencia presentada en: XII Congreso de la Asociación Española de Climatología celebrado en Santiago de Compostela entre el 19 y el 21 de octubre de 2022.[ES]Los bivalvos infaunales Ruditapes decussatus, Ruditapes philippinarum, Venerupis corrugata y Cerastoderma edule forman parte de una de las pesquerías con mayor importancia socioeconómica en las Rías Baixas (NO de España). El calentamiento del océano podría afectar a estas pesquerías ya que el aumento de la temperatura daría lugar a un incremento del estrés al que se ven sometidas estas especies, reduciendo su productividad e incluso propiciando cambios en su distribución geográfica. En este estudio se analizó cómo el aumento de la temperatura del agua podría afectar a la distribución geográfica de las zonas de confort térmico de estos bivalvos a finales del siglo XXI. El modelo Delft3D se utilizó para simular la hidrodinámica de las Rías Baixas durante los meses de julio y agosto del periodo histórico (1990-2019) y el periodo futuro (2075-2099) bajo el escenario RCP8.5. Durante el periodo histórico, las zonas más favorables para especies intermareales como R. decussatus, R. philippinarum y C. edule se observaron principalmente en la parte interior de las rías. Para V. corrugata, las zonas con confort se sitúan en el intermareal inferior y submareal somero. Las proyecciones futuras sugieren un aumento general de la extensión de las zonas con condiciones térmicas óptimas en comparación con el periodo histórico para R. decussatus, C. edule y V. corrugata. En el caso de R. philippinarum, la extensión podría disminuir en el futuro. Por último, la productividad de estas especies podría verse reducida en las áreas de marisqueo situadas en las zonas menos profundas de los sectores interiores de las Rías Baixas debido al aumento de la temperatura del agua.[EN]The infaunal bivalves Ruditapes decussatus, Ruditapes philippinarum, Venerupis corrugata and Cerastoderma edule are part of one of the most socio-economically important shellfisheries in the Rías Baixas (NW Spain). Ocean warming may affect these fisheries as the increase in water temperature would increase the stress conditions these species are subjected to. It could reduce their productivity and even change their geographical distribution. The present study analysed how rising ocean temperatures could affect the geographical distribution of the thermal comfort areas of these bivalves at the end of the 21st century. The Delft3D model was used to simulate the hydrodynamics of the Rías Baixas during the months of July and August of the historical period (1990-2019) and the future period (2075-2099) under the RCP8.5 scenario. Historically, the most comfortable areas for intertidal species such as R. decussatus, R. philippinarum and C. edule are mainly found in the inner part of the rias. For V. corrugata, the comfort zones are located in the lower intertidal and shallow subtidal. Future projections suggest a general increase in the extent of areas with optimal thermal conditions compared to the historical period for R. decussatus, C. edule and V. corrugata and a decrease for R. philippinarum. Finally, the productivity of these species could be reduced in the shellfishing areas located in the shallower areas of the inner sectors of the Rías Baixas due to the increase in water temperature

The CIM-UVigo plug-in hybrid propulsion vessel for coastal oceanographic research: a tool for the ecological transition

Peer Reviewe

Harnessing positive species interactions as a tool against climate-driven loss of coastal biodiversity

Habitat-forming species sustain biodiversity and ecosystem functioning in harsh environments through the amelioration of physical stress. Nonetheless, their role in shaping patterns of species distribution under future climate scenarios is generally overlooked. Focusing on coastal systems, we assess how habitat-forming species can influence the ability of stress-sensitive species to exhibit plastic responses, adapt to novel environmental conditions, or track suitable climates. Here, we argue that habitat-former populations could be managed as a nature-based solution against climate-driven loss of biodiversity. Drawing from different ecological and biological disciplines, we identify a series of actions to sustain the resilience of marine habitat-forming species to climate change, as well as their effectiveness and reliability in rescuing stress-sensitive species from increasingly adverse environmental conditions.EuroMarine - European Marine Research Networ