Recent Evolution (1956–2017) of Rodas beach on the Cíes Islands, Galicia, NW Spain

Sedimentary coastal areas change rapidly and are economically and environmentally important. This research focuses on determining the extent to which natural dynamics and human activity have contributed to visible changes on Rodas, Cíes Islands in southwestern Galicia (NW Spain). The number of visitors to the islands has increased in recent years, and the port infrastructure has therefore been expanded. Previously, this zone experimented with important sand extraction phases. These changes have influenced the ecosystem directly by modifying the sedimentary behavior and indirectly by promoting even greater numbers of visitors to the area. Aerial images and orthophotographs of the study zone were examined to identify changes that have taken place over the last sixty-one years (1956–2017). Changes in the position of the shoreline, defined as the boundary of the dune vegetation, were mapped at different times between 1956 and 2017. Changes in the shoreline were quantified using GIS (Geographic Information System) technology and Digital Shoreline Analysis System (DSAS) software. The findings revealed that the system regressed by more than 30 m between 1956 and 1981, in part as a result of sand extraction. We also identified different erosion/accretion phases that occurred before the reformation of the Rodas dock in 2010. The system is currently undergoing important changes, especially in the northern area, with a regression of 14.14 m in the last seven years. In this context, LiDAR analysis from 2010 and 2015 using Geomorphic Change Detection (GCD) tools allowed variations in the dune system to be verified. The elevation in the study zone increased in 83% of the area, mainly in the frontal dune and close to the winter inlet (north sector). However, the variations were very small.This work is part of a research project entitled Monitorización de los procesos biogeoquímicos en suelos de acantilados y aguas costeras en relación con la influencia de las colonias de aves marinas del Parque Nacional Marítimo Terrestre de las Islas Atlánticas de Galicia, funded by Organismo Autónomo Parques Nacionales (Ref. 041/2010) of Ministerio de Medio Ambiente, Medio Rural y Marino. The work of AGP is supported by an FPU predoctoral contract from the Spanish government (Ministerio de Educación, Cultura y Deporte). Grant Number: FPU16/03050.S

Seabird colonies as the main source of nutrients for the coastal ecosystems in the Atlantic Islands of Galicia National Park (NW Spain)

Seabirds form large colonies during the reproductive period, producing substantial changes in coastal ecosystems. The present study quantifies the amount of N and P deposited in colonies of yellow-legged gull (Larus michahellis) in the Atlantic Islands of Galicia National Park (AINP). Based on the composition of droppings, the amount of total N (TN), total P (TP) and bioavailable P (Pbio) deposited directly on the area occupied by the colony was determined. In addition, the amount of NH3 released into the atmosphere was also estimated by applying a bioenergetic model. The results indicated that 5.35 t total N, 3.35 t total P and 1.24 t bioavailable P are deposited in the colony annually. The archipelagos that received the greatest amount of nutrients were the Cíes Islands (2.37 t TN y−1, 1.48 t TP y−1, 0.55 t Pbio y−1), Sálvora (1.94 t TN y−1, 1.22 t TP y−1, 0.55 t Pbio y−1) and Ons (1.04 t TN y−1, 0.65 TP y−1, 0.24 t Pbio y−1). Rainwater from the colonies showed higher values of nutrients than in the control plot, possibly also due to gull influence. Therefore, the yellow-legged gull colony seems to be the most important source of nutrients at a local level, exerting a clear influence on the N and P cycles in this National Park. Another aspect worth taking into consideration is that increased N and P bioavailability may have a negative effect on the conservation of rare or threatened habitats and species by promoting the expansion of non-native ruderal speciesS

Trends in the Recent Evolution of Coastal Lagoons and Lakes in Galicia (NW Iberian Peninsula)

Coastal lagoons are habitats of great environmental value. However, they are currently subject to major threats, particularly due to increasing sea levels. This study aims to identify changes—both natural and induced by anthropic activity—and their impact on the recent evolution of three different types of coastal lagoons in Galicia (Louro, Vixán, and Xuño). The application of information obtained through laser imaging detection and ranging (LiDAR) techniques suggests that the outer limits of the three lagoon systems have not experienced any relevant changes in the last 60 years (i.e., no occupation of the lagoon area has been identified). However, the internal configuration of these wetland areas has experienced some alterations. A generalized increase in the area occupied by macrophytic communities (Phragmites australis, Scirpus maritimus, Juncus maritimus, etc.) has been observed. Image interpretation by geographic information systems (GIS) and field surveys suggest that the area currently occupied by macrophytes experienced a 7% to 63% increase at the expense of the free water body. This loss of flooded area is consistent with the increase in sedimentation rates associated with the convergence of several causes, such as the abandonment of traditional macrophyte biomass harvesting and agricultural activities around the lagoons, the expansion of riparian forests, and sediment contributions by erosion due to recurrent forest fires within the drainage basins of each lagoon. Finally, water and sediment composition suggest that, of the three studied lagoons, two of them (Louro and Vixán) are included within the definition of “coastal lagoons” (habitat code 1150) by the Habitats Directive (Directive 92/43/EEC), while the Xuño lagoon should be considered a “natural eutrophic lake” (habitat code 3150)This work is part of a research project entitled “Monitorización de los procesos biogeoquímicos en las lagunas litorales en relación con su calidad ambiental y respuesta al cambio climático” (Xunta de Galicia, PGIDIT08MDS036000PR), within the program for consolidation of competitive research groups (Xunta de Galicia-Consellería de Educación, Universidades e Formación Profesional, Plan Galego, ref. ED31C2018/12, Group ref. 2018-PG036) and Cross-Research in Environmental Technologies, CRETUS (Xunta de Galicia GRUP2015/02, ref. 2018-PG100). AGP is supported by an FPU predoctoral contract by the Spanish government (Ministerio de Educación, Cultura y Deporte). Grant Number: FPU16/03050S

Contribution of GIS and Geochemical Proxies to Improving Habitat Identification and Delimitation for the Natura 2000 Network: The Case of Coastal Lagoons in Galicia (NW Iberian Peninsula)

The Natura 2000 network is an ambitious European project aimed at nature conservation. Nevertheless, the identification and delimitation of habitats is a complex task and simultaneously essential for correct ecosystem management. In this study we compared the current habitat delimitation and designation and the results produced by Geographic Information Systems (GIS) and geochemical proxies for the categorization of four coastal lakes in Galicia (NW Iberian Peninsula). The findings reveal important errors in the delimitation/designation. The first error is the designation of all four lakes as Coastal lagoons (habitat 1150), when geochemical data indicate that two of these lakes were always freshwater lakes and should consequently be classified as Natural eutrophic lakes (habitat 3150). Another error is of conceptual origin, because the lakes comprise a unique functional system composing of different environmental units (e.g., open water or aquatic vegetation). Subdivision into different habitats is therefore meaningless for units of negligible surface area. In addition, the designation of some habitats is very dubious according to the available data. Finally, notable changes in relation to the temporal changes of wetlands were observed. Thus, the area occupied by aquatic macrophytes increased greatly at the expense of open waters, and the increase was also reflected in the alluvial forest. This last finding indicates the importance of updating the state of Natura 2000 network in Galicia to improve habitat managementThis work is part of a research project entitled “Monitorización de los procesos biogeoquímicos en las lagunas litorales en relación con su calidad ambiental y respuesta al cambio climático” (Xunta de Galicia, PGIDIT08MDS036000PR), the program for consolidation of competitive research groups (Axudas á consolidación e estruturación de unidades de investigación competitivas do SUG del Plan Galego IDT, Ambiosol Group ref. 2018-PG036), and Cross-Research in Environmental Technologies, CRETUS (Xunta de Galicia GRUP2015/02, ref. 2018-PG100). A.G.-P. is supported by an FPU predoctoral contract by the Spanish government (Ministerio de Educación, Cultura y Deporte). Grant Number: FPU16/03050S

Chemistry and genesis of soils developed under restinga vegetation in São Paulo State, Brazil

As áreas arenosas e de solos pobres com vegetação característica das planícies costeiras brasileiras são genericamente denominadas de restinga. Os solos desses ambientes foram muito pouco estudados. Para este estudo, selecionaram-se áreas de restinga dos municípios paulistas de Cananeia, Ilha Comprida e Bertioga devido à existência de diferentes unidades sedimentares, de vegetação remanescente e de solos, representativos da planície costeira do Estado de São Paulo. Nesses locais foram descritos e amostrados 31 perfis, muitos deles em cronossequência, objetivando caracterizá-los quimicamente e convergir evidências analíticas para elucidação dos principais mecanismos envolvidos na gênese dos Espodossolos - estes de ampla ocorrência no ecossistema restinga, componente do bioma Mata Atlântica nas planícies costeiras do Sudeste do Brasil. Para isso, foram utilizados procedimentos analíticos de rotina para fins de levantamento e classificação de solos, bem como de dissoluções seletivas dos elementos Fe (ditionito-citrato, oxalato e pirofosfato) e Al (ditionito-citrato, oxalato, pirofosfato, CuCl2, LaCl3 e KCl), os quais permitiram as seguintes interpretações: (a) a maioria dos solos de restinga estudados mostra-se de textura essencialmente arenosa e predominância de areia fina, com baixas soma e saturação por bases, reação extrema a fortemente ácida, capacidade de troca de cátions dependente da matéria orgânica e dominada por Al trocável, havendo aumento do conteúdo e estabilidade de carbono orgânico em profundidade. Esses atributos refletem a influência tanto do material de origem como do processo pedogenético predominante nesses ambientes: a podzolização; (b) o Al é o principal cátion envolvido na podzolização e suas formas ativas são: complexos de Al-húmus e compostos inorgânicos pouco cristalinos; (c) alguns horizontes espódicos com subscrito "s" (Bs, Bhs e Bsm), situados na base de perfis bem drenados, detêm os maiores valores de saturação por Al no húmus e estabilidade da interação carbono-metal entre todas as amostras e horizontes estudados; (d) existe estreita relação entre a idade dos Espodossolos e os atributos químicos analisados: os mais antigos (Cananeia) diferenciam-se dos demais quer pelos maiores conteúdos médios de C e de Al ativo (Al trocável, Al oxalato e Al pirofosfato), quer pela maior estabilidade da interação Al-húmus nos horizontes espódicos; e (e) estes se formaram predominantemente às expensas dos eluviais, com atuação de processos de queluviação de Al-húmus e sua imobilização em profundidade à medida que há saturação do elemento nos complexos organometálicos que migram no perfil.Restinga is a term currently used for the vegetation on the poor and sandy soils of the coastal plains of Brazil. The soils of these environments have been poorly studied. The counties Cananéia, Ilha Comprida and Bertioga were selected for this research due to the representativeness of the environmental conditions of the state of São Paulo. In these environments 31 soil profiles were described and sampled, many of them in chronosequences. The samples were characterized chemically and analytical evidence converged to elucidate the main mechanisms involved in the genesis of Spodosols, which are of widespread occurrence in the Restinga environments of Sao Paulo State and across Brazil. For these purposes, routine analytical procedures for soil survey and classification were used, as well as selective dissolution of the elements Fe (dithionite-citrate, oxalate and pyrophosphate) and Al (dithionite-citrate, oxalate, pyrophosphate, CuCl2, LaCl3 and KCl), resulting in the following interpretations: (a) most studied Restinga soils had a low sum of bases and base saturation, strong to extreme acidity, cation exchange capacity depending on the organic matter and dominated by exchangeable Al, with increasing content and stability of organic carbon with depth. These properties reflect the influence of both the parental material and the main predominant pedogenetic process in these environments: podzolization; (b) Al is the main cation in the podzolization process. The reactive forms of this element are Al-humus complexes and poorly crystalline inorganic compounds; (c) Al-humus saturation is highest in some spodic horizons with "s" subscript (Bs, Bhs and Bsm) located at the base of well-drained profiles and the metal-carbon interaction among all samples and horizons studied is stable; (d) there is a close relationship between Spodosol age and the chemical properties analyzed: the oldest (Cananéia) are differentiated from the others by higher mean content of C and active Al (exchangeable Al, Al oxalate and Al pyrophosphate) and greater stability of the interaction in Al-humus of spodic horizons; and (e) the spodic horizons studied were formed mainly at the expense of eluvial horizons and queluviation processes of Al-humus and its immobilization in depth through Al saturation in organo-metallic complexes migrating in the profile.À CAPES, pelo financiamento do doutorado-sanduíche do primeiro autor (convênio CAPES/MECD-DGU); à FAPESP, por meio do projeto "Solos sob vegetação de restinga no Estado de São Paulo: relações solo-paisagem, pedogênese e alterações com o uso agrícola", pelo apoio financeiroS

Analysis of total arsenic content in purchased rice from Ecuador

Natural and anthropogenic sources contribute to arsenic contamination in water and human food chain in Andean countries. Human exposure to arsenic via rice consumption is of great concern in countries where this crop is the dominant staple food, and limited information is available on the arsenic contamination on rice in Ecuador. This work was to contribute to the lack of knowledge analysing total arsenic by hydride generation-atomic absorption spectrometry in the samples of white, brown and parboiled rice purchased in Ecuadorian markets and produced in the two main rice wetlands in Ecuador, Guayas and Los Ríos, were carried out. For the samples from Guayas, arsenic concentration in white, brown and parboiled rice were 0.174 ± 0.014, 0.232 ± 0.021, and 0.186 ± 0.017 mg/kg respectively, whereas samples of white rice from Los Ríos showed a total arsenic level of 0.258 ± 0.037 mg/kg. This last arsenic concentration exceeds recommended maximum permissible limit by the FAO/WHO. Obtained data have available to estimate the Ecuadorian dietary exposure revealing serious health risk for population.S

Chemical composition of wildfire ash produced in contrasting ecosystems and its toxicity to Daphnia magna

It is well established in the world’s fire-prone regions that wildfires can considerably change the hydrological dynamics of freshwater catchments. Limited research, however, has focused on the potential impacts of wildfire ash toxicity on aquatic biota. Here, we assess the chemical composition and toxicity of ash generated from wildfires in six contrasting vegetation types distributed globally (UK grassland, Spanish pine forest, Spanish heathland, USA chaparral, Australian eucalypt forest and Canadian spruce forest). Acute (48 h) immobilisation tests were conducted on the extensively studied aquatic macroinvertebrate Daphnia magna, a sensitive indicator of aquatic contaminants. We found significant differences between the chemical composition and toxicity of these ash types. The UK and Spanish ash had no detectable toxicity to Daphnia magna, whereas the Australian eucalypt, USA chaparral and Canadian spruce ash all caused significant toxicity (immobilisation). The principal characteristics of the latter ash types were their high pH, and NO3, Cl and conductivity levels. Elevated water-soluble and total concentrations of metals (e.g. Mn, Fe, Zn, Pb, Cu and As) and total polycyclic aromatic hydrocarbons (PAHs) were not linked to toxicityThis work was supported by a Swansea University College of Science PhD studentship (Harper), a Leverhulme Trust Research Fellowship REF-2016–456\2 (Doerr) and a Ser Cymru Fellowship supported by European Union’s 2020 research and innovation program under the Marie Sklodowska–Curie grant agreement no. 663830 (Santin) and Natural Environment Research Ecotoxicology of wildfire-generated ash Int. J. Wildland Fire 735 Council (NERC) grant NE/R011125/1. Xose Luis Otero was supported by Cross-Research in Environmental Technologies (CRETUS) strategic group (Conselleria de Educacion REF. 2018-PG100)S

Pyrites in a salt marsh-ria system: quantification, morphology, and mobilization

Galician Rias are among the most productive ecosystems in the world. Consequently, the soils of their salt marshes and sediments of the intertidal flats show high organic matter contents, reactive Fe, and sulfate, which promote pyrite synthesis and accumulation, using sulfate for organic matter decomposition. This work studies the morphological variability and concentration of pyrites (individual crystals and framboids) in different geochemical environments found in the Ria de Ortigueira (salt marsh soils and bottom sediments in the inner, middle, and outer section), addressing their dynamics in the marsh-ria system in relation to the hydrodynamic characteristics defined by tides and river discharges. Framboidal pyrites were the dominant morphology in marsh soils and sediments in the middle and inner sections of the Ria, while isolated crystals dominated its outer section. The results showed that lower marsh soils (colonized by Spartina) are the most favorable environment for pyrite synthesis, showing high pyritic Fe concentrations and high degrees of pyritization, largely exceeding the values observed in sediments from Galician Rias and from most sedimentary environments worldwide. However, the amount of framboidal pyrites present in the lower marsh (SPE: 4–5 × 104 framboids) was clearly lower than in bottom sediments of the inner and middle part of the Ria de Ortigueira (∼2–7 × 106 framboids), mainly due to the fact that pyrites were found to form large framboids in lower salt marsh soils. Thus, the amount of framboidal pyrites does not seem to be a good indicator of redox conditions in modern marine sediments. Pyrite crystals found in the sediments of the Ria showed poorly defined vertices and facets, indicating their degradation and suggesting that a significant amount of the pyrites found in the middle and inner sections derive from marsh collapse. Finally, the output of framboidal pyrites towards the outer Ria de Ortigueira reflects the low intensity of residual flows in this Ria. Therefore, the pyrites observed in the outer section consisted only of isolated crystals, presumably formed in situ under low sulfate-reducing activity conditionsS

Gênese, Caracterização e Classificação de Solos de Mangue na Bacia do Rio Subaé, Bahia, Brasil

Preservation of mangroves, a very significant ecosystem from a social, economic, and environmental viewpoint, requires knowledge on soil composition, genesis, morphology, and classification. These aspects are of paramount importance to understand the dynamics of sustainability and preservation of this natural resource. In this study mangrove soils in the Subaé river basin were described and classified and inorganic waste concentrations evaluated. Seven pedons of mangrove soil were chosen, five under fluvial influence and two under marine influence and analyzed for morphology. Samples of horizons and layers were collected for physical and chemical analyses, including heavy metals (Pb, Cd, Mn, Zn, and Fe). The moist soils were suboxidic, with Eh values below 350 mV. The pH level of the pedons under fluvial influence ranged from moderately acid to alkaline, while the pH in pedons under marine influence was around 7.0 throughout the profile. The concentration of cations in the sorting complex for all pedons, independent of fluvial or marine influence, indicated the following order: Na+>Mg2+>Ca2+>K+. Mangrove soils from the Subaé river basin under fluvial and marine influence had different morphological, physical, and chemical characteristics. The highest Pb and Cd concentrations were found in the pedons under fluvial influence, perhaps due to their closeness to the mining company Plumbum, while the concentrations in pedon P7 were lowest, due to greater distance from the factory. For containing at least one metal above the reference levels established by the National Oceanic and Atmospheric Administration (United States Environmental Protection Agency), the pedons were classified as potentially toxic. The soils were classified as Gleissolos Tiomórficos Órticos (sálicos) sódico neofluvissólico in according to the Brazilian Soil Classification System, indicating potential toxicity and very poor drainage, except for pedon P7, which was classified in the same subgroup as the others, but different in that the metal concentrations met acceptable standards.A preservação de manguezais, ecossistema de elevada importância social, econômica e ambiental, requer conhecimento da composição, gênese, morfologia e classificação de seus solos, aspectos de fundamental importância para o entendimento da dinâmica e conservação sustentável desse recurso natural. Dessa forma, buscaram-se caracterizar e classificar solos de manguezais na bacia do Subaé e avaliar as concentrações dos poluentes inorgânicos. Foram escolhidos sete pedons representativos de manguezais, cinco sob influência fluvial e dois sob influência marítima, cujos perfis foram analisados quanto à morfologia e coletadas amostras de horizontes e camadas para posterior análise física e química, inclusive de metais pesados (Pb, Cd, Mn, Zn e Fe). Os solos em condições úmidas apresentaram-se subóxidos, com valores de Eh <350 mV. O pH dos pedons sob influência fluvial variaram de moderadamente ácido a alcalinos, enquanto os pedons sob influência marítima apresentaram valores em torno de 7,0 no longo de todo o perfil. A concentração de cátions no complexo sortivo para todos os pedons, independentemente da influência fluvial ou marítima, indicou a seguinte ordem: Na+>Mg2+>Ca2+>K+. Os solos dos manguezais da bacia do rio Subaé apresentaram características morfológicas, físicas e químicas distintas quando sob influência fluvial e marítima. As maiores concentrações de Pb e Cd foram identificadas nos pedons sob influência fluvial, possivelmente pela proximidade à Plumbum Mineração, e as menores concentrações encontravam-se no pedon P7, em razão da maior distância da fábrica. Por apresentar pelo menos um metal acima dos valores de referência indicados pela National Oceanic and Atmospheric (EPA), os pedons foram classificados como potencialmente tóxicos. Os solos foram classificados como Gleissolos Tiomórficos Órticos (sálicos) sódico neofluvissólicos de acordo com o Sistema Brasileiro de Classificação, apresentando-se potencialmente tóxicos, muito mal-drenados, exceto o pedon 7, que foi enquadrado no mesmo subgrupo dos demais, mas diferenciado deles por apresentar concentração de metal dentro dos limites tolerados.S

Natural and Anthropogenic Variations in the Large Shifting Dune in the Corrubedo Natural Park, NW Iberian Peninsula (1956–2017)

This work analyzes the evolution of the large shifting dune included in the Corrubedo Natural Park from 1956 until the present day. The analysis was carried out using aerial images, orthophotographs, topographic surveys and LiDAR (Light Detection and Ranging) data. Variations were analyzed in terms of four different aspects: evolution of pathways in each period, changes in the position of the mobile dune front and the degree of vegetation cover, all between 1956 and 2017; and variations in elevation and volume of the dune system between 2001 and 2015. To analyze these aspects, geospatial and geostatistical techniques were employed, which revealed that the dune front had undergone two different phases: one until the 1980s, with a mean seaward advance of 32 m and another one between the 1980 s and 2017, when the front prograded to the continent, with an approximate mean advance of 82 m. Loss of volume, related to the expansion of the mobile dune towards the north, was confirmed in this sector. It is evident that these changes are closely linked to anthropic influence, due to sand extraction until the early 1990s and, more recently, due to an increase in the number of visitors to the Natural Park. The results obtained highlight the need to carry out detailed studies to understand the evolution of this system and to prevent further damage in the future. Moreover, based on these analyses, a strategy to improve coastal and environmental management in the Corrubedo Natural Park could be designedThe work of AGP is supported by an FPU predoctoral contract from the Spanish government (Ministerio de Educación, Cultura y Deporte). Grant Number: FPU16/03050. The Consellería de Educación, Universidade e Formación Profesional-Xunta de Galicia (Axudas á consolidación e estruturación de unidades de investigación competitivas do SUG del Plan Galego IDT, (Ambiosol Group, ref. 2018-PG036). The authors belong to the CRETUS Institute. All these programs are co-funded by FEDER (UE)S