Chris Gaylarde

Microplastics (MPs) have been detected in many parts of the world in snow, hail, sea ice, glaciers, and permafrost. The ubiquity of microplastic around the globe means that there is a need to focus on its circulation dynamics in the Earth's diverse ecosystems; the prominence of MP fibers, which has been indicated as of human clothing and activities, in high altitude frozen water is explained by their enhanced suspension in the air, allowing them to be transported over long distances from urban centers. The MP particles can act as nucleation centers for ice crystals and, once incorporated, reduce the albedo (reflective capacity) of the frozen mass, causing temperature increases. However, cores have indicated that ice in glaciers may remain frozen for thousands of years. This article reviews the quantities and types of MPs that have been detected in snow, hail, sea ice, and glaciers. The potential for release of these, as well as MPs in the permafrost, following global warming, is...

Severe corrosion found on steel mooring components (CSMC) at several sites worldwide has caused concern in recent years as to whether the components can safely meet their design life. A pilot study was initiated to understand the underlying corrosion causes with the aim of developing successful CSMC mitigation methods. In 2014, a field test was conducted offshore at two different locations in West Africa in order to confirm the contribution of microbiologically influenced corrosion (MIC) to CSMC. The study provided evidence that MIC is a root cause of the observed severe corrosion in the form of mega-pits at one of the two test sites. The tests consisted of deploying carbon steel coupons on a fiber rope, herein referred to as a "microbial baiting kit", at facilities near the mooring systems to capture the biofilm forming microorganisms. The kit was submerged approximately three meters below the water surface for an extended period of time allowing for free swimming microor...

Nanoparticle-based materials are applied in the conservation of cultural heritage for their consolidating and self-cleaning abilities. Recently, nanoparticles (NPs) have been found to possess inherent antimicrobial activity, which has stimulated their application in the control of microbial colonization of stone and other mineral materials. A literature survey shows diverse testing procedures and limited research on the antimicrobial effectiveness of nanomaterials under real conditions. Most research reports laboratory-scale studies, employing either mono- or dual species (two organisms) assays over short-term incubation of days or weeks. Antimicrobial effectiveness is often assessed using microbiological, microscopy-based methods and surface colorimetry. There is a potential adverse ecotoxicological impact of NPs after release from treated surfaces. This chapter covers the antimicrobial properties of NPs and their limitations and advantages for application on built cultural heritage.

Bacteria, algae and fungi colonising dry (F1) and wet (F2) white painted walls in the fortress of Santa Cruz da Barra, Niteroi, Brazil, were detected using field emission-scanning electron microscopy (FE-SEM) and next generation DNA sequencing (NGS) techniques. Major bacterial phyla Operational Taxonomic Units (OTUs) detected were Chloroflexi in the wet green biofilm F2 (38.85% compared with 7.56% in F1) and Proteobacteria in the dry grey biofilm F1 (57.17% compared with 28.69% in F2). Diatoms were detected at both sites by FE-SEM, but only at F1 by NGS. More algae and cyanobacteria were identified at F1, and this was the only biofilm containing Archaea, possibly related to the high level of salt efflorescences at this site. Although thinner, F1 biofilm showed considerably higher genus richness than the wet biofilm, F2. The thickness and appearance of the biofilms did not correlate with their genomic complexity. Ascomycetes of the Sordariomycetes were major fungi identified at both sites, Khuskia (3.33% OTUs) at F1 and Emericellopsis (7.99% OTUs) at F2, and few filamentous forms were seen by microscopy. However, many fungal OTUs could not be identified to phylum level. Potential bacterial and fungal paint deteriogens were detected at both sites. The results confirmed the importance of using a variety of techniques in the study of microbial communities.

Weathering of two church facades in Rio de Janeiro was caused substantially by salts, mainly halite and gypsum, detected by SEM and chemical analyses, which cause physical stresses by deposition within the rock. Biofilm populations, determined by SEM and as operational taxonomic units (OTUs), degraded stone by penetration, solubilization and redeposition of minerals on their surfaces. Endolithic cyanobacteria were associated with gypsum deposits. Microbiomes were typical for high-stress environments, high salt, intense insolation, low water and low nutrients (eg halophilic Rubrobacter, Salinicola, Sterigmatomyces). The main colonizers on the church most affected by traffic (Nossa Senhora da Candelária - CA) were Actinobacteria; Gammaproteobacteria (chiefly Pseudomonas) were predominant on the site situated in a leafy square (São Francisco de Paula - SF). Major Gammaproteobacteria on CA were halophilic Halomonas and Rhodobacteriaceae. Fungal OTUs on both churches were principally dim...

Buildings at the important archaeological sites of Uxmal and Kabah, Mexico, are being degraded by microbial biofilms. Phospholipid fatty acid (PLFA) and chlorophyll a analyses indicated that phototrophs were the major epilithic microorganisms and were more prevalent on interior walls than exterior walls. Culture and microscopical techniques showed that Xenococcus formed the major biomass on interior surfaces, but the stone-degrading genera Gloeocapsa and Synechocystis were also present in high numbers. Relatively few filamentous algae and cyanobacteria were detected. The fatty acid analysis also showed that complex biofilms colonize these buildings. Circular depressions observed by scanning electron microscopy (SEM) on stone and stucco surfaces beneath the biofilm corresponded in shape and size to coccoid cyanobacteria. SEM images also demonstrated the presence of calcareous deposits on some coccoid cells in the biofilm. Phototrophic biofilms may contribute to biodegradation by (1) providing nutrients that support growth of acid-producing fungi and bacteria and (2) active ''boring'' behavior, the solubilized calcium being reprecipitated as calcium carbonate.

Chemical and biological weatheringwere studied on two historic churches in the city of Rio de Janeiro, Brazil. The churches exhibited contour scaling, granular disintegration and black crust development. High levels of SO4 were found in façade stones of one church, São José, with significant levels of lead and copper. This suggests that vehicle emissions were important in stonework decay. Both gypsumand halite were detected, typical of buildings influenced by marine atmosphere and fuel-polluted environment. There was little bioweathering on this church, although the filamentous cyanobacterium Scytonema detected could be involved in black crust production. The other church (Nossa Senhora da Gloria) showed strong granular disintegration,with a green coloration on internal surfaces of some flakes removed for study. This church showed lower levels of geochemically important weathering compounds but was more colonized by fungi and cyanobacteria. The latter were shown by scanning electron microscopy to grow within the granitic gneiss stone and were probably involved in dissolution and redeposition of minerals. This church is rather far from the intense traffic of the centre of Rio de Janeiro and from Guanabara Bay, source of marine aerosols; it is located upon a green hill, where plant-associated fungi and cyanobacteria can readily gain access to the façade. The results of this study showthe importance of local environment on the relative proportions of chemical and biological weathering of stone.