Biodisponibilidade da Matéria Orgânica dos Sedimentos Superficiais da Baía de Guanabara, Rio de Janeiro, Brasil

Thirty superficial sediment samples were collected in Guanabara Bay in order to identify new trophic state and environmental quality descriptors for coastal systems. A biochemical approach was used for analyzing the quality and quantity of sedimentary organic matter and metabolic bacterial activity. The samples were analyzed for particle size; organic matter, protein, carbohydrate, lipid, biopolymeric carbon, and bioavailable carbon levels; and bacterial metabolic activity. The results show a homogeneous spatial distribution for the anaerobic bacteria web and for biopolymers (carbohydrates>;lipids>;protein). The NE area of the bay displayed sediment lipid levels above 1 mg/g, indicative of organic sewage input. Spatial distribution of the superficial sediments in relation to other variables was not significant (p>;0.05). Biopolymers and labile organic matter showed a significant correlation with the average particle size of 80% of the fine particles. Despite the availability of labile organic matter, under the form of biopolymeric carbon, only 50% of the carbon was available to the trophic web. The bacterial consortia formed by sulfate reducing and denitrifying bacteria sustain the benthic trophic food web in Guanabara Bay.Foram coletadas 30 amostras de sedimentos superficiais na Baía de Guanabara, com o objetivo de identificar novos descritores de estado trofico e qualidade ambiental do ecossistema costeiro, usando análises bioquímicas para quantificar e qualificar a matéria orgânica sedimentar e o metabolismo bacteriano. Foram analisados a granulometria, teor de matéria orgânica, teores de proteínas, carboidratos, lipídeos, cabono biopolimérico, carbono biodisponível e atividade metabólica bacteriana. Os resultados mostraram uma distribuição espacial homogênea para a teia bacteriana anaeróbia e os biopolímeros (carboidratos>;lipídeos>;proteínas). O NE da Baía apresentou teores de lipídeos acima de 1 mg/g de sedimento, indicativo de aporte de esgoto orgânico. A distribuição espacial dos sedimentos superficiais em relação às variáveis não apresentou significância (p>;0,05). Os biopolímeros e a matéria orgânica apresentaram correlação significativa com a granulometria média de 80% dos finos. Apesar da disponibilidade de matéria orgânica lábil, sob a forma de carbono biopolimérico, o carbono disponível para a teia trófica está em torno de 50%. O consórcio bacteriano formado por bactérias sulfato redutoras e desnitrificantes sustentam a teia trófica bêntica da Baía de Guanabara

Subsídios para o planejamento estratégico costeiro do município de Jaguaruna, Santa Catarina

The unplanned occupation of the Coastal Zone has promoted the replacement of the original natural environment by the anthropic environment. This transformation generates conditions that unbalance the Environmental Diversity (abiotic and biotic natures) and prejudice the anthropic environment. This problem tends to continue and worsen in small municipalities; as is the case of municipality of Jaguaruna, Santa Catarina, Brazil. The present paper presents the method of structuring the first steps of a coastal strategic plan developed in Camacho Balneary/Jaguaruna through actions and scenarios of management based on conflict conditions mapping, the application of the Legal - Environmental Criticality Index (ICLA, in Portuguese), the paradigm of Geodiversity and the local sedimentary dynamics. In a Geographic Information System environment, the regionalization of the Environmental Diversity landscape was carried out by “map algebra” of abiotic and biotic information. After identifying and ranking the main conflict conditions by applying the ICLA, each conflict condition with an area over 1,000 m2 was evaluated. There were 71 conflict conditions, which cover 79.91% of the areas occupied with urban or agricultural activities. When comparing the results with the current management instruments, the main restrictions observed were: disrespect for legal and environmental constraints of occupation; poor sanitation; territory and urban zoning incoherent with the socio-spatial dynamics of Jaguaruna; lack of financial investment; and insufficient technical staff. The management scenarios allowed the design of three different types of intervention (medium term), which reflect different development proposals, for deliberation and implementation by public managers. The methodological proposal, combined with the incorporation of pre-existing management initiatives and plans, provided: the identification and hierarchy of conflict conditions in a simple and intelligible way; the proposition of objective management actions; the spatialization of trend scenarios and the continuity of pre-existing management initiatives.A ocupação sem planejamento da Zona Costeira tem promovido a substituição do ambiente natural original pelo ambiente antrópico, cuja implantação apresenta condições que desequilibram a Diversidade Ambiental (naturezas abiótica e biótica) e prejudicam o próprio ambiente antrópico. Essa problemática tende a continuar e se agravar em municípios pequenos, como é o caso de Jaguaruna/SC. O presente trabalho apresenta o método de estruturação das primeiras etapas de um planejamento estratégico costeiro desenvolvido no balneário Camacho/Jaguaruna por meio de ações e cenários de manejo baseados no mapeamento de condições de conflito, na aplicação do Índice de Criticidade Legal-Ambiental (ICLA), no paradigma da Geodiversidade e na dinâmica sedimentar. Em ambiente de Sistema de Informações Geográficas, foi realizada a regionalização paisagística da Diversidade Ambiental pelo cruzamento de informações das naturezas abiótica e biótica. Após a identificação e a hierarquização das principais condições de conflitos pela aplicação do ICLA, cada condição de conflito com área superior a 1.000 m2 foi avaliada. Foram encontradas 71 condições de conflito, as quais abrangem 79,91% das zonas ocupadas com atividades urbanas ou agrícolas. Ao confrontar os resultados com os instrumentos de gestão vigentes, as principais restrições observadas foram: desrespeito a condicionantes legais e ambientais de ocupação; saneamento básico deficiente; macrozoneamento e zoneamento urbano incoerentes com a dinâmica socioespacial do município; falta de investimento financeiro; e corpo técnico insuficiente. Os cenários de manejo permitiram projetar três tipos diferentes de intervenção (de médio prazo), que refletem distintas propostas de desenvolvimento, para deliberação e implementação por parte dos gestores públicos. A proposta metodológica, aliada à incorporação de diretrizes de outros instrumentos de gestão preexistentes, proporcionou: a identificação e a hierarquização de condições de conflito de forma simples e inteligível; a proposição de ações de manejo objetivas; a espacialização de cenários tendência e a continuidade de iniciativas de gestão preexistentes

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Bioavailability of Organic Matter in the Superficial Sediment of Guanabara Bay, Rio de Janeiro, Brazil

Thirty superficial sediment samples were collected in Guanabara Bay in order to identify new trophic state and environmental quality descriptors for coastal systems. A biochemical approach was used for analyzing the quality and quantity of sedimentary organic matter and metabolic bacterial activity. The samples were analyzed for particle size; organic matter, protein, carbohydrate, lipid, biopolymeric carbon, and bioavailable carbon levels; and bacterial metabolic activity. The results show a homogeneous spatial distribution for the anaerobic bacteria web and for biopolymers (carbohydrates>lipids>protein). The NE area of the bay displayed sediment lipid levels above 1 mg/g, indicative of organic sewage input. Spatial distribution of the superficial sediments in relation to other variables was not significant (p>0.05). Biopolymers and labile organic matter showed a significant correlation with the average particle size of 80% of the fine particles. Despite the availability of labile organic matter, under the form of biopolymeric carbon, only 50% of the carbon was available to the trophic web. The bacterial consortia formed by sulfate reducing and denitrifying bacteria sustain the benthic trophic food web in Guanabara Bay

Acquiring Iron-Reducing Enrichment Cultures: Environments, Methods and Quality Assessments

Lateritic duricrusts cover iron ore deposits and form spatially restricted, unique canga ecosystems endangered by mining. Iron cycling, i.e., the dissolution and subsequent precipitation of iron, is able to restitute canga duricrusts, generating new habitats for endangered biota in post-mining landscapes. As iron-reducing bacteria can accelerate this iron cycling, we aim to retrieve microbial enrichment cultures suitable to mediate the large-scale restoration of cangas. For that, we collected water and sediment samples from the Carajás National Forest and cultivated the iron-reducing microorganisms therein using a specific medium. We measured the potential to reduce iron using ferrozine assays, growth rate and metabolic activity. Six out of seven enrichment cultures effectively reduced iron, showing that different environments harbor iron-reducing bacteria. The most promising enrichment cultures were obtained from environments with repeated flooding and drying cycles, i.e., periodically inundated grasslands and a plateau of an iron mining waste pile characterized by frequent soaking. Selected enrichment cultures contained iron-reducing and fermenting bacteria, such as Serratia and Enterobacter. We found higher iron-reducing potential in enrichment cultures with a higher cell density and microorganism diversity. The obtained enrichment cultures should be tested for canga restoration to generate benefits for biodiversity and contribute to more sustainable iron mining in the region

Evaluation of sensitivity to zinc and copper of Diophrys appendiculata(Protozoa, Ciliophora) and their associated bacteria, both isolated from a tropical polluted bay

Ciliates are an essential component of microbial food webs, connecting biomass production to higher trophic levels and providing substrates for bacterial growth. Bacteria are widespread in sea sediment and the first to metabolize organic matter. Heavy metals are toxic and bind to particulate organic matter. This work aims to study the influence of heavy metals (Zn and Cu) on D. appendiculataand their naturally associated bacteria, both from Guanabara Bay during 96 h bioassay with 0, 0.001, 0.009, 0.05, 0.1 mg L-1 and maximum concentration stipulated by CONAMA 357 (Zn 5.0; Cu 1.0 mg L -1). It was analyzed for tolerance, resistance and biomass production. In Zn control, ciliate produced 1.24x10 2-2.47x10 3µg C cm -3 (0-96 h), with 0.009 mg Zn L-1 reaches 2.49x10 2 -1.93x10 3µg C cm -3 (0-96 h). Their naturally associated bacteria, in Zn control, produced 5.0x10 -2 -5.67x10 -2µg C cm -3 (0-96 h), with 0.1 mg Zn L-1 4.87x10 -2 -8.38x10-2µg C cm -3 (0-96 h). In Cu control, D. appendiculataproduced 1.04x10 2 -3.12x10 2µg C cm -3 (0-96 h), with 0.009 mg Cu L-1 biomass was 8.31x10 1 -7.27x10 -2µg C cm -3 (0-96 h) and with CONAMA concentration was below detection level. Their naturally associated bacteria, in Cu control, produced 1.20x10-2 -5.14x10 -2µg C cm -3 (0-96 h) and with 0.1 mg Cu L -1 7.40x10 -4  -3.81x10 -2µg C cm -3  (0-96 h), with CONAMA concentration 5.14x10 -2 µg C cm-3 (96 h). D. appendiculataare tolerant to 0.09 mg L -1 and resistant to 0.1 mg L -1 after 24 h to Zn-Cu and LD50 stipulated was 1.17 (Zn) 0.90 (Cu) mg L -1 . Microbial loop was functional in low concentration of Zn and Cu, but their diversity in nature was affected

Covellite (CuS) Production from a Real Acid Mine Drainage Treated with Biogenic H₂S

Acid Mine Drainage (AMD) is an environmental problem associated with mining activities, which resulted from the exposure of sulfur bearing materials to oxygen and water. AMD is a pollution source due to its extreme acidity, high concentration of sulfate, and soluble metals. Biological AMD treatment is one alternative to couple environmental amelioration for valuable dissolved metals recovery, as a new source of raw materials. Covellite (CuS) particles were synthetized from an AMD sample collected in a Brazilian copper mine, after 48 and 96 h of exposure to hydrogen sulfide (H2S) produced in a bioreactor containing acidophilic sulfate reducing bacteria (SRB). The time of exposure affected the morphology, nucleation, and size of CuS crystals. CuS crystals synthetized after 96 h of H2S exposure showed better ordination as indicated by sharp and intense diffractograms obtained by X-ray diffraction (XRD), and the predominance of placoid sheets with hexagonal habit structure as observed by scanning electrons microscopy (SEM). Energy dispersive X-ray fluorescence (EDXRF) spectrometry indicated a Cu:S molar ratio in agreement with CuS. Granulometric analysis demonstrated that 90% of CuS particles were less than 22 µm size. AMD biological treatment is a potential economical CuS recovery option for metallurgical process chain incorporation, or new industrial applications, since the alteration of synthesis conditions can produce different crystal forms with specific characteristics

Influence of copper on Euplotes sp. and associated bacterial population

The influence of copper on the ciliate Euplotes sp. and associated bacteria isolated from sediment samples of Guanabara Bay were investigated in bioassays. This region is highly affected by heavy metals such as copper, from solid waste constantly dumped in the bay and other sources such as industrial effluents, antifouling paints, atmospheric deposition and urban drainage, and even today there are few data on the metal toxicity to the ecosystem of the Bay of Guanabara. Bioassays were conducted to estimate the LC50-24 h of copper, in order to determine the concentration of metal bearing 50% of the population mortality. The results indicated that the concentrations of 0.05 and 0.009 mg L-1 presented no toxicity to Euplotes sp. The associated bacteria are tolerant to copper concentrations used in bioassays, and suggest that they could be used as a potential agent in the bioremediation of areas affected by copper