Deterioration of limestone structures associated with copper staining

Sixty limestone monuments in Central London, UK, with copper staining from brass or bronze attachments, were surveyed. Severe spalling was noted at some copper-stained sites. The survey suggests that copper initially protects the surface, but causes stone deterioration after around 70 years. Samples from four limestone monuments were analysed microbiologically and using ESEM/EDX. EDX analyses suggested the build-up of salts below a basic copper carbonate skin (salting) as the most probable explanation of the observed deterioration. Copper-stained stone was free of photosynthetic microorganisms and yielded relatively few other microorganisms. ESEM and EDX analyses of a well-conserved limestone monument surface free of copper showed the almost complete conversion of surface limestone to gypsum. The grey/brown biofilms consisted of actinomycetes and filamentous fungi. The results indicate that copper initially prevents and then enhances limestone deterioration, and that atmospheric pollutants are far less harmful than phototrophic biofilms, since surface areas completely converted to gypsum are well preserved after more than 100 years.     

Section of tropical taxonomy: Seven new species and one new record of Polygala (Polygalaceae) from Somalia

The following new species are described: Polygala gypsophila (northern, central and southern Somalia, on gypsum), P. bariensis (northern Somalia, on limestone), P. hamarensis (coastal dunes near Mogadishu), P. argentea (central Somalia, on limestone near coast), P. gawenensis (central Somalia, on limestone), P. effusa (central Somalia and eastern Ethiopia, on sand), P. citrina (southern Somalia, on granitic outcrops). P. meonantha is reported for the first time from Somalia.     

New species and combinations in Kleinia (Asteraceae) from the Horn of Africa

The new species Kleinia tuberculata , from open deciduous bushland on gypsum hills and gypseous limestone in northern and north-eastern Somalia, K. curvata , from evergreen bushland on limestone in northern Somalia, K. sabulosa , from deciduous bushland on sand in central Somalia, K. ogadensis , from deciduous bushland in eastern Ethiopia, K. gracilis , from dwarf bushland on limestone in north-eastern Somalia, and K. tortuosa , from alkaline plains in northern Somalia, are described, and for some of them illustrations are provided. The new combinations K. nogalensis and K. lunulata are made, and the recently described K. isabellae from eastern Ethiopia is placed in synonymy of K. lunulata.     

Eight new species and a new record of Indigofera and Microcharis (Leguminosae-Indigofereae) from Somalia

The following new species are described: Indigofera bayensis (south-west Somalia, on sand or gravel in Acacia-Commiphora bushland), I. gypsacea (central and south-west Somalia, on gypsum), I. karkarensis (north-east Somalia, on limestone), I. lamellata (south-west Somalia, on and around granitic outcrops), I. lughensis (south-west Somalia, on gypsum), I. phymatodea (south-west Somalia, on granitic outcrops), I. scopiformis (central Somalia, on sand in Acacia-Commiphora bushland), and Microcharis nematophylla (central Somalia, on sand in Acacia-Commiphora bushland). Indigofera pseudointricata , previously known only from Socotra, is reported also from Somalia.     

Characterization,feasibility and optimization of Agaricus subrufescens growth based on chemical elements on casing layer

The aim of this study was to analyze yields, biological efficiency, earliness (expressed as days to first harvest), and precociousness and establish models for the mushroom growing according to these parameters. The experiment followed a double factorial design with four sources of calcium (calcitic limestone, calcitic limestone + gypsum, dolomitic limestone and dolomitic limestone + gypsum) and 2 application times (25 days before casing and at the moment of casing), with 4 replicates for each treatment. Different calcium sources influenced differently Agaricus subrufescens production, especially as regards earliness, which showed significantly higher values when dolomitic limestone with gypsum was applied. Yield and biological efficiency were negatively correlated with H + AL, organic matter and Mg amount. Furthermore, earliness was positively correlated with H + Al, organic matter, and the amount of Mg and Fe. Finally, negative correlations were observed between precociousness and the amount of Ca, SB (sum of base), CEC (cation exchange capacity) and V% (percentage of base saturation). The models presented in this work are extremely important for predicting the agronomic performance of Agaricus subrufescens on the basis of chemical analysis provided by the casing soil.     

Two new species of Polygala (Polygalaceae) from Somalia

The new species Polygala praetermissa , a dwarf perennial herb growing in stony places on limestone, and P. dasanensis , a shrublet apparently confined to gypsum, are described. Both species occur in the Cal Miskaat Range in north-eastern Somalia, but P. praetermissa has a wider distribution in northern Somalia.     

ALGAL LIMESTONES WITH PSEUDOMORPHS AFTER GYPSUM FROM THE MIDDLE JURASSIC OF SCOTLAND

Hudson, J. D.: Algal limestones with pseudomorphs after gypsum from the Middle Jurassic of Scotland. Lethaia , Vol. 3, pp. 11–40. Oslo, January 15th, 1970.
Algal limestones from two horizons within the Great Estuarine Series of the Hebrides are described. That from the Mytilus Shales is a typically stromatolitic limestone formed by algal trapping and binding of micrite pellets. Calcite pseudomorphs after gypsum occur along some of the laminae. The limestones from the Lower Ostrea Beds include less regularly-stromatolitic types, and nodular algal limestones that contain tubes of calcified algae, notably Cayeuxia nodosa Anderson. The algal nodules also yield uncalcified tubes composed of organic material, that are comparable to recent Schizothrix. These algae form inter-growths similar to those recorded from the recent supratidal deposits of the Bahamas. The algal nodules are often coated with microtufa. Pellet- and spheru-lite-limestones are associated with the algae, and pseudomorphs after gypsum are again found. Isotopic data on the carbonate-carbon, and the palaeoecological implications of the algae and the pseudomorphs are discussed.     

Effects of limestone and gypsum application to a Malaysian ultisol on soil solution composition and yields of maize and groundnut

A field experiment was conducted on an Ultisol in Malaysia to assess changes in soil solution composition and their effects on maize and groundnut yields, resulting from limestone and gypsum application. The results showed that soil solution Ca in the lime treatment remained mainly in the zone of incorporation, but in the gypsum treatment some Ca moved into 15–30 cm zone. Al³⁺ and AlSO₄ ⁺ were dominant Al species in the soil solution of nil treatment. Liming decreased Al³⁺ and AlSO₄ ⁺, but increased hydroxy-Al monomer activities. However, gypsum application resulted in an increase of AlSO₄ ⁺ activity and in a decrease of Al³⁺ activity. Relative maize and groundnut yields were negatively correlated with Al³⁺, Al(OH)²⁺ and Al_sum activities. Likewise, relative yields were negatively correlated with Al concentration and the Al concentration ratio and positively correlated with soil solution Mg concentration and Ca/Al ratio.     

Physical and chemical limnology of northern boreal lakes, Wood Buffalo National Park, northern Alberta and the Northwest Territories, Canada

Physical and chemical variables were measured in 35 lakes from Wood Buffalo National Park, northern Alberta and the Northwest Territories, Canada. Of these lakes, 22 were sinkholes, situated on limestone and gypsum, five were situated on the Canadian Shield and eight were shallow 'muskeg' lakes located on calcareous shales. All of the lakes were small to moderate in size. For each of the 35 lakes, 37 environmental variables were measured. Principal component analysis (PCA) revealed that underlying geology strongly influenced limnic properties. Shield lakes were characterized by higher concentrations of A1 and Fe, and lower pH values, specific conductivities and concentrations of ions such as, Ca, SO4, Li, Mg and Na, than either the sinkhole or the muskeg lakes. The muskeg lakes were differentiated from the sinkhole lakes by decreased Secchi depth owing to higher concentrations of dissolved organic carbon (DOC) and greater productivity, as evidenced by high concentrations of particulate organic carbon (POC) and chlorophyll a. Nitrogen (NH3 and NO2) was also notably higher at these sites. The 22 sinkhole lakes were further classified by the type of surrounding vegetation. Six vegetation groups were recognized: (1) spruce; (2) pine; (3) mixed; (4) shrubs/poplar; (5) recently burned and (6) rocky. These vegetation groups largely reflect fire history, but also differences in soils and drainage. Unlike geology, surrounding vegetation, and therefore recent fire history, generally had little influence on limnic properties. PCA showed that of the six vegetation groups, only the spruce lake group, which was characterized by high levels of DIC, was distinct. This revised version was published online in July 2006 with corrections to the Cover Date.     

Alleviation of soil acidity in Ultisol and Oxisol for corn growth

Malaysian Ultisols and Oxisols are characterized by low pH, high soil solution Al concentration and Ca and/or Mg deficiencies, which are limiting to corn growth. An experiment was conducted to determine the changes in solid and soil solution phase properties of a representative Ultisol and Oxisol following applications of ground magnesium limestone (GML), gypsum and their combinations, and their effects on corn growth. A plot of pAl against lime potential (pH-1/2 pCa) showed that the points were mostly positioned between the theoretical lines for kaolinite-quartz and gibbsite equilibrium, reflecting the kaolinitic-oxidic mineralogy of the Ultisol and Oxisol. Gypsum application increased Al concentration in the soil solutions of the Ultisol, but had no significant effect on that of the Oxisol. The increase in Al concentration in the Ultisol was due to an increase in ionic strength. Gypsum application increased soil solution pH of the Oxisol due to release of OH as a result of ligand exchange between SO₄ and OH ions on the oxides of Fe and/or Al. Exchangeable Al in both soils was reduced by gypsum application. The reduction was associated with solid phase immobilization through alunite formation; the soil solutions of soil samples treated with 2 and 4 t gypsum ha⁻¹ were supersaturated with respect to alunite. Application of GML at 2 t ha⁻¹ together with 1–2t gypsum ha⁻¹ gave high top weight of corn. Relative top weight of corn was positively correlated with a soil solution Mg and Ca/Al concentration ratio, but negatively correlated with soil solution Al concentration. Foliar Al corn was positively correlated with soil solution Al concentration. Soil solution Al and Mg concentrations, and Ca/Al concentration ratio can be used as indices of soil acidity in Ultisols and Oxisols. ei]{gnB E}{fnClothier}     

Flavonoid diversity and geographic endemism in Parthenium

The distribution of 34 flavonoids detected in the North American species of Parthenium indicates that flavonoid diversity and structural types are correlated with biological aspects of different species types. Widespread species occurring in a variety of habitat types are characterized by greater numbers of flavonoids, primarily as the result of flavonoid glycoside diversity; while species which are geographically isolated in limestone or gypsum habitats are characterized by a tendency to depauperate flavonoid patterns with major methylated aglycone components. The possibility that glycosylation is related to self-detoxification and preservation of toxic phenolic potential is discussed. It is shown that parallel chemical adaptations, similar to the well-known parallel morphological adaptations of unrelated species which coexist in certain habitats, may occur     

Palaeoecology of the Aptian Santana Formation (Northeastern Brazil)

In the interior of northeastern Brazil there occurs the Santana Formation of Aptian age, composed lithologically of three members: Crato — an alternation of thin limestones and shales; Ipubi — gypsum; and Romualdo — almost pure limestone. The formation is very fossiliferous; pollen, plant remains, ostracodes, conchostracans, mollusks, echinoids, fishes and a few reptiles. The fishes and reptiles occur in limestone concretions. All data on sediment character and on fossils have been considered together for the interpretation of the palaeoenvironment of the formation.It was concluded that at the time of the Crato Member the deposition occurred in shallow lakes and swamps. Later (Ipubi Member), a marine invasion took place during a time of dry climate, causing anhydrite precipitation. Gradually the connection with the sea became obstructed so that the environment at the end of the depositional period became once more one of fresh water (Romualdo Member). Faunal assemblages and sediments point to a fairly great supply of river water during the whole time of basin deposition, under warm and dry climatic conditions. The connection with the sea persisted for a rather short period.     

Methane in sulfate-rich and sulfate-poor wetland sediments

Wetlands of northern Belize provide a unique opportunity to study methane production and emissions from marshes dominated by identical species (Typha domingensis, Cladium jamaicense) and genus (Eleocharis spp.), but differing substantially in the amount of sulfates present in the sediments. Some marshes occur on limestone marls rich in gypsum (CaSO₄) while others are underlain by alluvial sands poor in sulfates. Concentrations of methane and sulfates in the sediment interstitial water are one or more orders of magnitude different for these two geological substrata averaging 139.2 and 14.9 M of CH₄, and 0.08 and 11.53 mM of SO₄ ^–2 2 on alluvial sands and limestone respectively. The amount of methane found in the internal atmosphere of plants from alluvial sands is significantly higher (6.3 M) than in plants from limestone (0.19 M). The average methane emissions measured in wetlands located on alluvial sands were 25.2 mg m^–2 h^–1 while emissions from marshes on limestone were only 2.4 mg m^–2 h^–1. These values extrapolated for the entire year and the respective wetland areas resulted in the estimate of total CH4 emissions from northern Belize of 0.066 Tg per year.     

The ecological equivalence of quarry floors to alvars

Question: Are the biophysical conditions of abandoned limestone quarry floors and natural alvars sufficiently similar to each other for alvars to be used as a model for quarry floor restoration? Location: Ontario, Canada. Methods: We measured plant species frequency and environmental and soil variables in 13 abandoned limestone quarries and used ANOVA to compare them with data previously collected from seven natural alvars. We used multivariate ordinations on the quarry floor data alone and on the combined quarry floor and alvar data to determine how plant community structure was controlled by the abiotic environment in both habitats. Results: Except for higher levels of many nutrients, the physical characteristics were similar between quarry floors and alvars. 246 plant species were found on quarry floors as compared to 283 on alvars, with 79 species in common between the two habitat types. While quarry floors supported fewer bryophytes and more exotic vascular plants compared with alvars, five alvar endemics and 24 characteristic alvar species were found to grow there. The age of the site, nutrient levels, and presence of standing water and bare rock were important factors influencing species composition in both habitats. Conclusions: Through natural revegetation alone, the abandoned quarry floors surveyed in this study have already taken on many physical and vegetation characteristics of natural alvars. This makes alvars very suitable as the restoration goal for abandoned limestone quarries.     

Effects of adding calcium and sodium salts to field soils on the incidence of clubroot

The effect on clubroot of the addition to a mineral soil of calcium carbonate, calcium sulphate and sodium carbonate was studied in two field experiments during a 3-yr period. Applications of calcium carbonate (ground limestone) at 10 or 20 t/ha increased the soil pH from 6×7 to 7×9; sodium carbonate at 7×5 t/ha to pH 8×3 and calcium sulphate (gypsum) at 20 t/ha caused a slight depression in pH to 6×6. 98% of cabbage plants showed clubroot symptoms in the untreated plots after 3 yr and the percentages were 0×7, 1×6 and 66×6 for the calcium carbonate, sodium carbonate and calcium sulphate treatments respectively. Yields were significantly increased by all three materials. There were no significant differences in disease incidence or in yield when calcium carbonate was used at 10 or 20 t/ha either applied as a single application or as two half-rate applications. Soil from the calcium carbonate treated plots was used in a greenhouse experiment where the addition of inoculum of Plasmodiophora brassicae resulted in a large increase in clubroot incidence. There was no evidence that a biological suppressor was present in the high pH, low disease incidence soils.     

Lack of Complete Exposure Pathways for Metals in Natural and FGD Gypsum

Use of wallboard made from synthetic gypsum generated via flue-gas desulfurization (FGD) by coal-fired power plants (FGD gypsum) raised questions concerning the potential for exposure to residual trace metals. Because gypsum is widely used (e.g., in wallboard), any issue with metals could have far-reaching implications. A conceptual site model evaluated potential human health exposure pathways for metals in gypsum, through consideration of data for 21 metals including samples of natural (mined) gypsum, and of FGD gypsum. Because there are no screening values for gypsum, comparisons were made to background soil concentrations and to risk-based concentrations for metals in soil termed preliminary remedial action goals (PRGs), which assume more frequent and prolonged contact with particulate soil than would be likely for gypsum, and thus provide a health protective means for evaluation of exposure. Additional screenings evaluated occupational exposure and agricultural use of gypsum. Maximum metal concentrations in natural and FGD gypsum samples were either consistent with background concentrations or much lower than PRGs for residential or agricultural soil, or workplace air, and thus exposure pathways for these media were considered incomplete. Separate analyses of mercury volatilization were conducted, and this pathway was also found to be incomplete.     

Halophilic Microorganisms Are Responsible for the Rosy Discolouration of Saline Environments in Three Historical Buildings with Mural Paintings

A number of mural paintings and building materials from monuments located in central and south Europe are characterized by the presence of an intriguing rosy discolouration phenomenon. Although some similarities were observed among the bacterial and archaeal microbiota detected in these monuments, their origin and nature is still unknown. In order to get a complete overview of this biodeterioration process, we investigated the microbial communities in saline environments causing the rosy discolouration of mural paintings in three Austrian historical buildings using a combination of culture-dependent and -independent techniques as well as microscopic techniques. The bacterial communities were dominated by halophilic members of Actinobacteria, mainly of the genus Rubrobacter. Representatives of the Archaea were also detected with the predominating genera Halobacterium, Halococcus and Halalkalicoccus. Furthermore, halophilic bacterial strains, mainly of the phylum Firmicutes, could be retrieved from two monuments using special culture media. Inoculation of building materials (limestone and gypsum plaster) with selected isolates reproduced the unaesthetic rosy effect and biodeterioration in the laboratory.     

The microbe–mineral environment and gypsum neogenesis in a weathered polar evaporite

Evaporitic deposits are a globally widespread habitat for micro‐organisms. The microbe–mineral environment in weathered and remobilized gypsum from exposed mid‐Ordovician marine evaporite beds in the polar desert of Devon Island, Nunavut, Canadian High Arctic was examined. The gypsum is characterized by internal green zones of cyanobacterial colonization (dominated by Gloeocapsa/Aphanothece and Chroococcidiopsis spp. morphotypes) and abundant black zones, visible from the surface, that contain pigmented cyanobacteria and fungi. Bioessential elements in the gypsum are primarily provided by allochthonous material from the present‐day polar desert. The disruption, uplift and rotation of the evaporite beds by the Haughton meteorite impact 39 Ma have facilitated gypsum weathering and its accessibility as a habitat. No cultured cyanobacteria, bacteria and fungi were halophilic consistent with the expectation that halophily is not required to persist in gypsum habitats. Heterotrophic bacteria from the evaporite were slightly or moderately halotolerant, as were heterotrophs isolated from soil near the gypsum outcrop showing that halotolerance is common in arctic bacteria in this location. Psychrotolerant Arthrobacter species were isolated. No psychrophilic organisms were isolated. Two Arthrobacter isolates from the evaporite were used to mediate gypsum neogenesis in the laboratory, demonstrating a potential role for microbial biomineralization processes in polar environments.     

Effect of different levels of gypsum application on soil characteristics and growth and yield of rice (Oryza sativa L.)

Summary A field experiment was conducted to compare the efficacy of application of different fractions of gypsum requirement (0, 20, 40, 60, 80 and 100%) for reclaiming alkali lands for rice cultivation. The experiment was initiated in the year 1971 and the effect of treatments was observed for three consecutive years (upto 1973) in terms of rice growth and yield and also the chemical characteristics of the soil. Economics of rice production was also worked out for different treatments.Results obtained revealed that a fairly good crop of rice with a small profit margin could be raised in the first year itself, by applying 20% of the gypsum requirement. Higher levels of gypsum proved economical only during subsequent years. Application of gypsum beyond 80% of the requirement was of no avail. Soil pH declined in all the treatments with its magnitude dilating with increased gypsum application. Electrical conductivity was also brought down with rice cultivation, irrespective of the quantum of gypsum.     

Unravelling the mechanisms for plant survival on gypsum soils: an analysis of the chemical composition of gypsum plants from Turkey

Depending on their specificity to gypsum, plants can be classified as gypsophiles (gypsum exclusive) and gypsovags (non‐exclusive). The former may further be segregated into wide and narrow gypsophiles, depending on the breadth of their distribution area. Narrow gypsum endemics have a putative similar chemical composition to plants non‐exclusive to gypsum (i.e. gypsovags), which may indicate their similar ecological strategy as stress‐tolerant plant refugees on gypsum. However, this hypothesis awaits testing in different regions of the world. We compared the chemical composition of four narrow gypsum endemics, one widely distributed gypsophile and six gypsovags from Turkey. Further, we explored the plasticity in chemical composition of Turkish gypsovags growing on high‐ and low‐gypsum content soils. Differences were explored with multivariate analyses (RDA) and mixed models (REML). Narrow gypsum endemics segregated from gypsovags in their chemical composition according to RDAs (mainly due to higher K and ash content in the former). Nevertheless, differences were small and disappeared when different nutrients were analysed individually. All the gypsovags studied accumulated more S and ash when growing on high‐gypsum than on low‐gypsum soils. Similar to narrow gypsum endemics from other regions of the world, most local gypsum endemics from Turkey show a similar chemical composition to gypsovags. This may indicate a shared ecological strategy as stress‐tolerant plants not specifically adapted to gypsum. Nevertheless, the narrow gypsum endemic Gypsophila parva showed a chemical composition typical of gypsum specialists, indicating that various strategies are feasible within narrowly distributed gypsophiles.