Pollutants potential mobilization in Santos bay/Brazil: subsidies for the environmental management of a highly anthropized estuary: Potencial de mobilização de poluentes na baía de Santos/Brasil: subsídios para a gestão ambiental de um estuário altamente antropizado

Understanding the dynamics and spatial variation of subaquatic sediment contamination in the Santos Estuarine System has been of interest to the scientific community and environmental managers; the hazardous contaminant compounds, either individually or synergistically, can affect the health of the local community. In the present study, water column salinity and sediment geochemical properties (calcium and organic matter content, grain size) of the Santos Estuarine System were correlated with heavy metal concentrations (As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn and Fe) in order to elucidate the relationship between the toxic elements and the dynamics of water mixing. To assess the potential relationships, Spearman’s correlation test and Principal Component Analysis (PCA) between were applied. The heavy metal concentrations were also evaluated by calculating Contamination Factor, Geoaccumulation index and Enrichment Factor. Results revealed extremely heterogeneous particle sizes within the sampling stations. Most of the heavy metal concentrations were not at critical levels. The only exception was arsenic, which reached levels above the threshold effect. The statistical analysis allowed the influence of organic matter and grain size on the dynamics of heavy metal accumulation to be demonstrated. The values between these binding matrices and metals were mostly significant. Bottom water salinity, on the other hand, showed no apparent influence on the distribution of metals. However, the various pollution indices used were contradictory, with certain cases presenting critical results. The Geoaccumulation Index presented the Mn as highly polluting at all sampling stations and classified the environment as moderately polluted by Zn. The same pollution pattern was not found by the other contamination indexes

Influence of Environment on Microbial Colonization of Historic Stone Buildings with Emphasis on Cyanobacteria

Microbial cells that produce biofilms, or patinas, on historic buildings are affected by climatic changes, mainly temperature, rainfall and air pollution, all of which will alter over future decades. This review considers the colonization of stone buildings by microorganisms and the effects that the resultant biofilms have on the degradation of the structure. Conservation scientists require a knowledge of the potential effects of microorganisms, and the subsequent growth of higher organisms such as vascular plants, in order to formulate effective control strategies. The vulnerability of various structural materials (“bioreceptivity”) and the ways in which the environmental factors of temperature, precipitation, wind-driven rain and air pollution influence microbial colonization are discussed. The photosynthetic microorganisms, algae and cyanobacteria, are acknowledged to be the primary colonizers of stone surfaces and many cyanobacterial species are able to survive climate extremes; hence special attention is paid to this group of organisms. Since cyanobacteria require only light and water to grow, can live endolithically and are able to survive most types of stress, they may become even more important as agents of stone cultural property degradation in the future

The Importance of Biofilms on Microplastic Particles in Their Sinking Behavior and the Transfer of Invasive Organisms between Ecosystems

Although plastic is ubiquitous in marine systems, our current knowledge of its transport is limited. Recent studies suggest size-selective removal of small plastic particles (<5 mm) from the ocean surface as a result of the formation of a biofilm (the “plastisphere”) on the microplastic particle (MP) surface. This localized microenvironment can isolate the microcosm from the adjacent aqueous medium, and thus protect component alien species from the surrounding physico-chemical conditions. Apart from resulting in specific conditions for the transfer of alien species through the environment, the plastisphere can impact MP hydrodynamics and cause MPs to move through the water column, initially sinking. The importance of this phenomenon has not been previously considered for these particles. The size-dependent vertical movement of MPs through the water column determines their distribution, which will vary with time of exposure and colonization. Some plastisphere organisms have plastic-degrading activities, which could be harnessed in marine depollution strategies. This article seeks to increase our understanding of the role of biofilms in the biological dynamics and diffusion of plastic microparticles

Microbiologically induced aesthetic and structural changes to dimension stone

Abstract Dimension stone is natural rock prepared for building use. It is rapidly colonised by microorganisms that cause discoloration (mainly cyanobacteria, algae and fungi) and structural damage. Microbial mobilisation of ions leads to new superficial or internal deposits, weakening the structure. Cyanobacteria and fungi may penetrate, filling pores or creating new spaces. Lichens, fungus/phototroph associations, colonise surfaces and damage stone through ingrowing rhizines and acid production. Initial degradation produces conditions suitable for germination of seeds of higher plants and further destruction. Emerging techniques to elucidate stone-cell interactions and control of initial biofilm formation that eventuates in stone disintegration are discussed

Transfer of bacteria between stainless steel and chicken meat: A CLSM and DGGE study of biofilms

This study aimed to assess the interaction between bacteria and food processing surfaces using novel methods. Microbial cross contamination between stainless steel, a common food processing material, and raw chicken was studied using microbiological culture, specialized microscope and molecular techniques. Confocal laser scanning microscopy (CLSM) allowed the visualization of biofilms containing single or dual species of Escherichia coli O157:H7, Salmonella typhimurium, Bacillus cereus, Staphylococcus aureus and Pseudomonas aeruginosa, formed after 6 days’ incubation on stainless steel or 4h on raw chicken. The results provided information on intra-biofilm location and stratification of species within dual species biofilms. Top-to-bottom Z-stack images revealed that, on both materials, S. typhimurium and E. coli attached concurrently, the former in greater numbers. E. coli and B. cereus segregated on steel, E. coli more frequent near the metal surface, B. cereus almost the only species in outer layers. Few cells of S. aureus, found at all depths, were seen in the 2.9 µm thick biofilm on steel with E. coli. Greatest attachment was shown by P. aeruginosa, followed by S. typhimurium, E. coli and finally Gram positive species. Large amounts of EPS in P. aeruginosa biofilms made visualization difficult on both materials, but especially on chicken meat, a limitation of this technique. Nevertheless, CLSM was useful for determining time sequence of adhesion and species makeup of thin biofilms. The technique showed that five min contact between bacterially-contaminated chicken and sterile steel resulted in greatest transfer of P. aeruginosa, followed by S. typhimurium. This was confirmed using DGGE. Gram positive bacteria transferred poorly. A biofilm containing 2.3 × 105  cfu·cm−2 B. cereus on steel transferred an undetectable number of cells to chicken after 5 min contact. This species was unable to form biofilm on chicken when incubated for 4 h in growth medium. S. typhimurium and P.aeruginosas were most efficiently transferred from contaminated steel to raw chicken within 5 min contact, with 20–30% transfer from single species biofilms. All other species, and all cells in dual species biofilms, showed less than 2% transfer. CLSM and DGGE were shown to be useful techniques for the study of bacterial adhesion to stainless steel

Effect of culture medium on biocalcification by Pseudomonas Putida, Lysinibacillus Sphaericus and Bacillus Subtilis

The objective of this study is to investigate the efficiency of calcium carbonate bioprecipitation by Lysinibacillus sphaericus, Bacillus subtilis and Pseudomonas putida, obtained from the Coleção de Culturas do Instituto Nacional de Controle de Qualidade em Saúde (INCQS), as a first step in determining their potential to protect building materials against water uptake. Two culture media were studied: modified B4 containing calcium acetate and 295 with calcium chloride. Calcium consumption in the two media after incubation with and without the bacterial inoculum was determined by atomic absorption analysis. Modified B4 gave the best results and in this medium Pseudomonas putida INQCS 113 produced the highest calcium carbonate precipitation, followed by Lysinibacillus sphaericus INQCS 414; the lowest precipitation was produced by Bacillus subtilis INQCS 328. In this culture medium XRD analysis showed that Pseudomonas putida and Bacillus subtilis precipitated calcite and vaterite polymorphs while Lysinibacillus sphaericus produced only vaterite. The shape and size of the crystals were affected by culture medium, bacterial strain and culture conditions, static or shaken. In conclusion, of the three strains Pseudomonas putida INQCS 113 in modified B4 medium gave the best results precipitating 96% of the calcium, this strain thus has good potential for use on building materials