Effects of biochar and the earthworm Eisenia fetida on the bioavailability of polycyclic aromatic hydrocarbons and potentially toxic elements

Polycyclic aromatic hydrocarbons (PAHs) and potentially toxic elements (PTEs) were monitored over 56 days in calcareous contaminated-soil amended with either or both biochar and Eisenia fetida. Biochar reduced total (449 to 306mgkg(-1)) and bioavailable (cyclodextrin extractable) (276 to 182mgkg(-1)) PAHs, PAH concentrations in E. fetida (up to 45%) but also earthworm weight. Earthworms increased PAH bioavailability by >40%. Combined treatment results were similar to the biochar-only treatment. Earthworms increased water soluble Co (3.4 to 29.2mgkg(-1)), Cu (60.0 to 120.1mgkg(-1)) and Ni (31.7 to 83.0mgkg(-1)) but not As, Cd, Pb or Zn; biochar reduced water soluble Cu (60 to 37mgkg(-1)). Combined treatment results were similar to the biochar-only treatment but gave a greater reduction in As and Cd mobility. Biochar has contaminated land remediation potential, but its long-term impact on contaminants and soil biota needs to be assessed.

Provenance of chalk tesserae from Brading Roman Villa, Isle of Wight, UK

Thin section petrographical analysis of chalk tesserae at Brading Roman Villa, Isle of Wight, England, identifies a range of planktonic foraminifera and the calcareous algal cyst Pithonella that identify the Late Cenomanian Rotalipora cushmani Biozone (BGS Foraminiferal Biozones 4iii to 7). The local chalk crop to the north of the villa includes rocks of R. cushmani Biozone age, and indicates a likely local, rather than long distance, source for the tesserae. Microfossils provide a powerful tool for identifying the provenance of artefacts in Roman Britain.

Limiting factors in the restoration of grassland insects

Grasslands restoration is a key management tool contributing to the long-term maintenance of insect populations, providing functional connectivity and mitigating against extinction debt across landscapes. As knowledge of grassland insect communities is limited, the lag between the initiation of restoration and the ability of these new habitats to contribute to the successful enhancement of native biodiversity is unclear. Using two long term data sets, we investigate differences in successional trajectories during the establishment of butterfly (11 years) and phytophagous beetle (13 years) communities during the recreation of calcareous grassland. Overall restoration success was higher for the butterflies than the beetles. However, both shared a general pattern of rapidly increasing restoration success over the first five years, awhich approached an asymptote after c. 10 years. The use of pro-active grassland restoration to mitigate against future environmental change therefore needs to account for such time lag if the value of these habitats is to be fully realised.

The water quality of the River Enborne, UK: observations from high-frequency Monitoring in a rural, lowland river system

This paper reports the results of a 2-year study of water quality in the River Enborne, a rural river in lowland England. Concentrations of nitrogen and phosphorus species and other chemical determinands were monitored both at high-frequency (hourly), using automated in situ instrumentation, and by manual weekly sampling and laboratory analysis. The catchment land use is largely agricultural, with a population density of 123 persons km−2. The river water is largely derived from calcareous groundwater, and there are high nitrogen and phosphorus concentrations. Agricultural fertiliser is the dominant source of annual loads of both nitrogen and phosphorus. However, the data show that sewage effluent discharges have a disproportionate effect on the river nitrogen and phosphorus dynamics. At least 38% of the catchment population use septic tank systems, but the effects are hard to quantify as only 6% are officially registered, and the characteristics of the others are unknown. Only 4% of the phosphorus input and 9% of the nitrogen input is exported from the catchment by the river, highlighting the importance of catchment process understanding in predicting nutrient concentrations. High-frequency monitoring will be a key to developing this vital process understanding.

Combined use of satellite estimates and rain gauge observations to generate high-quality historical rainfall time series over Ethiopia

Climate data are used in a number of applications including climate risk management and adaptation to climate change. However, the availability of climate data, particularly throughout rural Africa, is very limited. Available weather stations are unevenly distributed and mainly located along main roads in cities and towns. This imposes severe limitations to the availability of climate information and services for the rural community where, arguably, these services are needed most. Weather station data also suffer from gaps in the time series. Satellite proxies, particularly satellite rainfall estimate, have been used as alternatives because of their availability even over remote parts of the world. However, satellite rainfall estimates also suffer from a number of critical shortcomings that include heterogeneous time series, short time period of observation, and poor accuracy particularly at higher temporal and spatial resolutions. An attempt is made here to alleviate these problems by combining station measurements with the complete spatial coverage of satellite rainfall estimates. Rain gauge observations are merged with a locally calibrated version of the TAMSAT satellite rainfall estimates to produce over 30-years (1983-todate) of rainfall estimates over Ethiopia at a spatial resolution of 10 km and a ten-daily time scale. This involves quality control of rain gauge data, generating locally calibrated version of the TAMSAT rainfall estimates, and combining these with rain gauge observations from national station network. The infrared-only satellite rainfall estimates produced using a relatively simple TAMSAT algorithm performed as good as or even better than other satellite rainfall products that use passive microwave inputs and more sophisticated algorithms. There is no substantial difference between the gridded-gauge and combined gauge-satellite products over the test area in Ethiopia having a dense station network; however, the combined product exhibits better quality over parts of the country where stations are sparsely distributed.

Cereal aphids and their natural enemies: responses to landscape composition and agri-environment schemes

There are potential conflicts between food security, biodiversity conservation and ecosystem services. Currently, there are still gaps in our understanding on the links between land use, biodiversity and ecosystem services; all have implications for sustainable agriculture. To improve food productivity in an ecologically friendly manner we should consider adapting current pest control techniques from being reliant on chemical means towards a more integrated approach. However, to do this, farmers and land owners require more information in order to make informed decisions. This brief review explores field level and landscape scale impacts on aphid control by their natural enemies. This will be done by exploring the effects of local field margin flower strips and two key landscape scale factors, winter wheat and lowland calcareous grasslands on aphids and their natural enemies. Research questions which need answering are discussed.

Are existing biodiversity conservation strategies appropriate in a changing climate?

Many countries have conservation plans for threatened species, but such plans have generally been developed without taking into account the potential impacts of climate change. Here, we apply a decision framework, specifically developed to identify and prioritise climate change adaptation actions and demonstrate its use for 30 species threatened in the UK. Our aim is to assess whether government conservation recommendations remain appropriate under a changing climate. The species, associated with three different habitats (lowland heath, broadleaved woodland and calcareous grassland), were selected from a range of taxonomic groups (primarily moths and vascular plants, but also including bees, bryophytes, carabid beetles and spiders). We compare the actions identified for these threatened species by the decision framework with those included in existing conservation plans, as developed by the UK Government's statutory adviser on nature conservation. We find that many existing conservation recommendations are also identified by the decision framework. However, there are large differences in the spatial prioritisation of actions when explicitly considering projected climate change impacts. This includes recommendations for actions to be carried out in areas where species do not currently occur, in order to allow them to track movement of suitable conditions for their survival. Uncertainties in climate change projections are not a reason to ignore them. Our results suggest that existing conservation plans, which do not take into account potential changes in suitable climatic conditions for species, may fail to maximise species persistence. Comparisons across species also suggest a more habitat-focused approach could be adopted to enable climate change adaptation for multiple species.

Avaliação do teor de cal livre em escória de aciaria elétrica

A escória de aciaria elétrica é um resíduo gerado no processo de fabricação de aço, que apresenta propriedades físicas adequadas quando aplicada em alguns materiais da área de construção civil. Entretanto, possui algumas limitações causadas pela presença de compostos que sofrem reações expansivas quando exposta ao ambiente (óxidos de cálcio e magnésio livres, óxidos de ferro e silicatos de cálcio), provocando rupturas e desintegração dos materiais onde é aplicada. Além disso, quando usada como base e sub-base na construção de estradas, pode ocorrer a formação de tufa (calcário precipitado) causando entupimento de drenos das rodovias. O presente trabalho tem como objetivo avaliar o teor de cal livre em escória de aciaria elétrica utilizando a combinação de um método titulométrico com análise térmica, pois é um dos compostos mais citados pela literatura como responsável pela expansão da escória. Dois métodos titulométricos foram selecionados para determinar o teor de cal livre, onde o primeiro foi desenvolvido para análise em cimento (Método do etilenoglicol) e o segundo foi adaptado para escória de aço (Método de Franke) Os resultados mostraram que o método de Franke, extraído da norma européia EN 1744:1998, foi o mais adequado para determinar cal livre em escórias de aciaria elétrica. A quantidade de cal livre encontrada não permitiu avaliar sua variação ao longo do tempo de exposição, somente considerando os métodos titulométricos. Entretanto, utilizando o método de análise térmica, observou-se um decréscimo no número de reações do primeiro mês de exposição com relação aos meses seguintes, sugerindo uma estabilização das escórias ao longo do tempo. Também, os resultados para cal original (em torno de 1%) sugerem uma potencialidade de formação de tufa. Finalmente, esse estudo mostrou que é fundamental a associação dos métodos titulométrico e de análise térmica para uma adequada avaliação de cal livre em escórias de aciaria elétrica.

Caracterização hidrológica e geoquímica das áreas adjacentes aos bancos oceânicos do nordeste brasileiro

O objeto deste trabalho é fornecer dados hidrológicos com fins de caracterização e monitoramento da região da Cadeia Norte do Brasil e da Cadeia de Fernando de Noronha, assim como levantar e sistematizar informações sobre a geoquímica dos diversos tipos de sedimentos encontrados na plataforma continental externa adjacente ao banco Aracati, contribuindo para o levantamento dos potenciais sustentáveis de exploração dos recursos vivos da Zona Econômica Exclusiva. A área em estudo compreende a sub-área II, setor 1 e parte do setor 2, e está localizada entre 1oN e 5oS de latitude e entre 30o e 40oW de longitude, abrangendo uma área de aproximadamente 400.000 km2. Foram analisadas amostras coletadas em 8 estações resultando em 20 amostras de sedimentos nos anos de 1997 (verão), 1998 (outono) e 2000 (primavera) e 34 estações que originaram 272 amostras de água na primavera de 2000. As concentrações máximas dos parâmetros analisados, com exceção do fosfato, nas amostras de água se localizam na região próxima à costa. Detectou-se na área uma termoclina bem marcada, sendo mais profunda na primavera. A camada de mistura é bastante homogênea, sendo porém, mais espessa na primavera. O pH detectado encontra-se na faixa alcalina sendo os maiores valores de pH detectados na primavera. Verifica-se, um máximo de salinidade na camada de inicio da termoclina sazonal. Não verificou-se na área condição anaeróbica na coluna d’água. A distribuição de fosfato, nitrato e silicato, apresenta-se de forma muito semelhante, sendo que na primavera essas concentrações são maiores, nas camadas superficiais. Na cobertura sedimentar da plataforma continental adjacente aos bancos da cadeia norte do Brasil, encontro-se areia quartzosa, areia carbonática, fragmentos de concha, Lithothanmium e Halimedas. Os fragmentos de concha apresentaram as maiores concentrações totais de metais, enquanto Lithothanmium apresentou o maior teor de carbonato. Há uma forte correlação entre ferro e manganês na amostras de água e em todas as frações de sedimentos analisadas, sendo que nestas a relação média entre estes elementos é da ordem de 1:25. Existe forte correlação entre cromo e carbonato nas amostras que apresentam teor de carbonato maior que 20%. As amostras de areia quartzosa, fragmentos de concha e Halimedas, apresentam-se muito semelhantes quanto à distribuição de ferro, manganês, zinco e cromo. Existe forte correlação nas amostras de sedimento, assim como nas amostras de água, entre ferro, manganês, zinco, correlacionando-se também nas amostras de sedimento com o chumbo. As 8 concentrações de metais nas amostras de água apresentaram-se relativamente baixas em se comparando com as amostras de sedimento. Nas amostras de água as concentrações de cromo e chumbo estão abaixo do limite de detecção.

Diversidade de macroalgas marinhas bentônicas dos recifes de Maracajaú, área de preservação ambiental dos recifes de corais, Rio Grande do Norte, Brasil

Despite the importance of coral reefs to humanity, these environments have been threatened throughout the world. Several factors contribute to the degradation of these ecosystems. The Maracajaú Reef Complex, in Rio Grande do Norte state is part of the Coral Reefs Environment Preservation Area in northeastern Brazil. This area has been receiving an increasing influx of tourism and the integrity of the local reefs is a matter of concern. In this study, the reef macroalgae communities were studied and compared within two areas distinguished by the presence or absence of tourism activities. Two sample sites were chosen: the first one, where diving activities are intense; and the other, where these practices do not occur. Samples were collected at both sites within a quadrate of 625 cm2 of area randomly thrown 5 times along a 10 meters transect line. Richness, Shannon-Hill diversity and Simpson dominance indices were determined based on biomass data. Similarity between sites was analyzed with Bray-Curtis similarity and distance index. Fifty-eight macroalgae species were observed, including 7 Chlorophyta, 13 Phaeophyta and 38 Rhodophyta. In the non-disturbed site, 49 species were found, while at the disturbed site, there were 42 species. Dictyotaceae and Corallinaceae were the most representative families at the non-disturbed site, and Rhodomelaceae and Dictyotaceae at the disturbed site. The non-disturbed site presented a higher biomass and the greatest richness and diversity indices. In the disturbed site the dominance index was greater and Caulerpa racemosa was the dominant species. The dendogram based on similarity index showed two major clusters, and an isolated element at the center that corresponds to a sample from the disturbed site. In the first cluster, samples from the non-impacted site were predominant and fleshy brown algae were more conspicuous. The second cluster was composed primarily of samples from the impacted site, where C. racemosa and red filamentous and erect calcareous algae associations (turf forming) were observed covering large extensions. These associations are represented by groups of algae adapted to environments where disturbances are frequent. They can grow rapidly on substrate where benthic community was removed and do not allow the establishment of other species. The results of the present study show that tourism activity is an impacting factor that has been causing shifts in macroalgae communities in the Maracajaú Reef Complex

Influência do teor de calcário no comportamento físico, mecânico e microestrutural de cerâmicas estruturais

There are ores of clay in Piauí State that are used for red structural ceramics, which are naturally contaminated with calcareous vein. This is one thing that impedes its exploration in an adequate way, especially for tile production. The present work aims at verifying the influence of the calcareous contents in the technological structural ceramics area, seeking to determine a maximum permissible calcareous proportion/contents in the ceramic mass using the patterns of the local industry production. For the consecution of this paper, it was characterized the clay and calcareous material by FRX, DRX, TGA and DTA. It was also configurated by extrusion and burnt in the temperatures of 850°C, 900°C, 950°C and 1000°C pieces of the corpus with 0, 5, 10, 15 e 20% of calcareous proportion. After that, it was carried out technological samples of linear retraction, water absortion, apparent porosity, specific apparent mass and mechanic resistance. The results showed the possibility of using calcareous in the ceramic mass and in some cases the technological properties got better

Aproveitamento de resíduos minerais na formulação de argamassas para a construção civil

Current environmental concerns include the excessive consumption and inefficient use of non-renewable natural resources. The construction industry is considered one of the largest consumers of natural raw materials, significantly contributing to the environmental degradation of the planet. The use of calcareous quarry (RPPC) and porcelain tile polishing residues (RPP) as partial replacements of the cement in mortars is an interesting alternative to minimize the exploration of considerably large amounts of natural resources. The present study aimed at investigating the properties of fresh and hardened mortars produced using residues to replace cement. The residues used were fully characterized to determine their specific mass, unitary mass, particle size distribution and morphology, and composition. The performance of the mortars was compared to that of reference compositions, prepared without residues. A total of 18 compositions were prepared, 16 using residues and 2 reference ones. The mortars were prepared using Portland CP II F 32 cement, CH I hydrated lime, river sand and tap water. The compositions of the mortars were 1:1:6 and 1:0.5:4.5 (vol%), and water to cement ratios of 1.87 and 1.45 were used, respectively. The mortars in the fresh state were evaluated by consistency index, water retention, density of mass and incorporated air content tests. In their hardened state, the mortars were evaluated by apparent mass density, modulus of elasticity, flexural tensile strength, compressive strength and water absorption by capillarity. The mortars were also analyzed by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction and fluorescence. Finally, they were classified according to NBR 13281 standards. The mortars prepared using residues partially replacing the cement exhibited lower modulus of elasticity compared to the reference compositions, thus improving the performance in their intended use. On the downside, the water absorption by capillarity was affected by the presence of residues and both the tensile and compressive strength were reduced. However, from the overall standpoint, the replacement of cement by calcareous quarry or porcelain tile polishing residues did not result in significant changes in the properties of the mortars. Therefore, compositions containing these residues can be used in the construction industry

Sistema de recirculação e rotina de manejo para larvicultura de camarões de água doce Macrobrachium rosenbergii em pequena escala

A recirculating system and a matching management schedule for small-scale freshwater prawn larviculture were described. The system comprised a 140 L larval culture tank in line with a 43 L biofilter filled with 24 L of calcareous substrate. Both the tank and biofilter were made of black colored fiberglass in a conical-cylindrical shape. The turnover rate of the water through the system was 24 times a day; water was pumped by airlift. Results of ten larvicultures showed that the system maintained temperature, dissolved oxygen, pH, salinity, ammonium and nitrite stable and suitable to Macrobrachium rosenbergii larvae. Survival and productivity varied from 60.5 to 72.4% and 37 to 72 post-larvae/L, respectively; both were compatible with results of commercial hatcheries. Therefore, this system may be very useful for research purposes or adapted for small-scale post-larvae production.

Efeito de níveis crescentes de calagem no crescimento e estado nutricional de fedegoso

A distribuição e desenvolvimento de plantas, a exemplo daquelas que infestam as áreas agrícolas, é influenciada por diversos fatores, a como aqueles ligados às caraterísticas do solo, naturais ou impostas pelo homem. Assim, o presente trabalho de pesquisa foi desenvolvido em condições de casa-de-vegetação com o objetivo de estudar o efeito de níveis crescentes de calagem no crescimento e estado nutricional de Senna obtusifolia, planta daninha comum em ecossistemas agrícolas. O delineamento experimental adotado foi o inteiramente casualizado, com seis tratamentos e quatro repetições. Os tratamentos constituíram-se em quantidades de calcário dolomítico calcinado com 38% de CaO e 20% de MgO, com um poder de neutralização total (PRNT) de 104%: 0, 2, 4, 6, 8 e 10 t/ha. As parcelas experimentais constituíram-se de recipientes de plástico com capacidade de 5 litros, preenchidos com terra coletada na camada arável de um latossolo vermelho escuro distrófico, A moderado, textura média. Após um período de crescimento de 56 dias as plantas foram coletadas e separadas em seus componentes vegetativos, sendo colocados a secar em estufa de circulação forçada de ar (70ºC por 72 horas) para determinação do peso seco. O material foi pesado e moído e analisado a nível de composição de nutrientes. Os resultados mostraram efeitos negativos dos níveis crescentes de calcário, sobre o crescimento das plantas de S. obtusifolia, evidenciando-se decréscimos nos valores da matéria seca acumulada a partir da dose de 4 t/ha de calcário (pH 5,8), com efeitos mais marcantes nas raízes. A aplicação de doses crescentes de calcário promoveu um aumento progressivo nos teores de Ca e Mg no solo, o que talvez possa ter estimulado a competição entre cátions, reduzindo a absorção do K. Os elementos N e P foram os mais absorvidos pela planta.