The rock-phosphate solubilizing capacity ofPueraria javanica as affected by soil pH,superphosphate priming effect and symbiotic N2 fixation

Summary WhenPueraria javanica was grown on acid soil in a pot experiment, the legume’s acidifying effect, originating from an uptake pattern in which on an equivalence basis more nutritive cations than-anions were absorbed, was sufficient to mobilize rock phosphate even when added as very insoluble material. In neutral soil, a small quantity of triple superphosphate proved necessary to set into motion a chain of reactions in which the priming action of the TSP enables nodulation to take place followed, in order, by N₂ fixation, soil acidification and rock phosphate mobilization. More attention should be paid in tropical regions to mixed farming systems in which leguminous crops, like Pueraria, produce fodder for livestock whose faeces and urine, when properly collected, can be used for the manufacturing of biogas, after which the residues can serve as manure to food crops. Even when they prove unsuitable for beneficiation, many rock phosphates found in African and Latin American countries can be made useful as fertilizer for leguminous fodder crops.     

Biodecay of cultural heritage as a space/time-related ecological situation — an evaluation of a series of studies

Mural paintings and stone monuments are exposed to natural and man-made hazards for time spans sometimes longer than 10,000 years without total decay. On the other hand, a high percentage of the mineral physical heritage suffers severe damage and even total loss within a few decades. Several factors influence this general situation. The mural paintings of Lascaux and Altamira had been stabilized in a protective environment for millennia until they were re-exposed to severe environmental risks. Wall paintings and stone sculptures may remain unaltered for many years through: (1) stabilized and protective environments, (2) development of a protective patina (biofilm, minerals, organics) or, (3) more recent additional paint or mortar layers, which themselves are exposed to environmental hazard instead of the fresco underneath. Natural or artificial coverage, however, will invariably hinder evaluation and appreciation of the object of art. Detrimental microorganisms often only sporadically interact with these precious paintings. Many microbes settling on and in mural paintings are of a unusual metabolic type, namely poikilotrophic organisms. These poikilotrophs are capable of forming a biocoenosis on and in mural paintings, which may establish itself within a few months or years and then remains unchanged in a dormant or non-cultivable state for many years, or even centuries. The same holds true for chemical and physical alterations brought about by microorganisms. After a damaging initiation period of growth, the microflora may turn into a biofilm, which continues to live at extremely low levels of metabolic activity. In this way, detrimental chemical, physical and biological activities may be screened or shielded off for a very long period of time. In order to understand these processes, we have studied poikilotroph sub-aerial biofilms of mural paintings and sculptures excavated after long periods of dormancy. Several methods for the characterization of the physical properties of the colonies of fungi involved in colonization and deterioration of mural paintings and stone monuments are described. The fairy-tale of “The Sleeping Beauty” maybe an excellent metaphor for this phenomenon. The main issue, however, is to understand the physical or mechanical impact of the poikilotroph flora on the materials of the physical heritage studied.     

The mechanism of rock phosphate solubilization in the rhizosphere

Summary A simple model is described, and experimentally tested, for predicting the rate of dissolution of rock phosphates in soil, including the effect of solubilization by plant roots. The sensitivity of the model to its input parameters is assessed and it is seen that plants may significantly increase their P uptake by acid secretion. The model provides a rational basis for the selection of P solubilizing crops and inter-crops.     

The Effects of Inorganic Phosphates on Trochophore Larvae of the Oyster,Crassostrea virginica

Summary

Trochophore larvae were exposed to monosodium orthophosphate (MSOP), sodium hexametaphosphate (SHMP), sodium tripolyphosphate (STPP), and tetrasodium pyrophosphate (TSPP) at concentrations of 15 ppm and 150 ppm phosphate for 24, 48, and 72 hr. All four compounds caused morphological developmental changes, increased mortality, and inhibition of shell growth at both 15 ppm and 150 ppm. The rank order of effectiveness of the compounds was determined from percentage abnormal larvae, percentage survival, and from shell measurements. The order was MSOP>SHMP>STPP≥TSPP for abnormality and mortality and TSPP>STPP>MSOP>SHMP for shell growth inhibition. The relative effect of the individual compounds in causing mortality varied with the time of exposure. Orthophosphate retarded growth rates of the two valves to different degrees.     

Geomicrobiological Study of the Grotta dei Cervi,Porto Badisco,Italy

Speleothems (active stalactites, wall concretions), rock walls, ceiling, and soils from the galleries of Grotta dei Cervi, Porto Badisco, Italy, were sampled to investigate the culturable heterotrophic microbial communities present in this cave. Sampling was carried out in a transect of about 230 m from the entrance to the central gallery where numerous Gram-positive bacteria were isolated from all studied sites. Members of the genera Agromyces, Arthrobacter, Rhodococcus , and particularly Streptomyces , of the order Actinomycetales, are spread throughout the whole cave. The ability of actinomycetes, and particularly of Nocardiopsis , to colonize salt-stressed environments is favored by the presence of ectoine, a compatible solute for osmotic adaptation. Selected actinomycete isolates were tested for the formation of crystals. Strains from all tested genera, except isolates of Gordonia and Nocardia , produced vaterite and/or calcite. Production of Mgcalcite was restricted to strains of Brachybacterium, Rhodococcus , and Streptomyces , whereas struvite was only precipitated by an unidentified isolate. These findings indicate that actinomycetes may play a role in the formation of mineral deposits in caves.     

Molecular identification of Trichoderma species associated with Pleurotus ostreatus and natural substrates of the oyster mushroom

Green mold of Pleurotus ostreatus , caused by Trichoderma species, has recently resulted in crop losses worldwide. Therefore, there is an emerging need for rapid means of diagnosing the causal agents. A PCR assay was developed for rapid detection of Trichoderma pleurotum and Trichoderma pleuroticola , the two pathogens causing green mold of P. ostreatus . Three oligonucleotide primers were designed for identifying these species in a multiplex PCR assay based on DNA sequences within the fourth and fifth introns in the translation elongation factor 1α gene. The primers detected the presence of T. pleurotum and/or T. pleuroticola directly in the growing substrates of oyster mushrooms, without the need for isolating the pathogens. The assay was used to assess the presence of the two species in natural environments in which P. ostreatus can be found in Hungary, and demonstrated that T. pleuroticola was present in the growing substrates and on the surface of the basidiomes of wild oyster mushrooms. Other Trichoderma species detected in these substrates and habitats were Trichoderma harzianum, Trichoderma longibrachiatum and Trichoderma atroviride. Trichoderma pleurotum was not found in any of the samples from the forested areas tested in this study.     

Weathering versus atmospheric sources of strontium in ecosystems on young volcanic soils

We used isotopes of Sr to quantify weathering versus atmospheric sources of foliar Sr in 34 Hawaiian forests on young volcanic soils. The forests varied widely in climate, and in lava flow age and texture. Weathering supplied most of the Sr in most of the sites, but atmospheric deposition contributed 30–50% of foliar Sr in the wettest rainforests. A stepwise multiple regression using annual precipitation, distance from the ocean, and texture of the underlying lava explained 76% of the variation in Sr isotope ratios across the sites. Substrate age did not contribute significantly to variation in Sr isotope ratios in the range of ages evaluated here (11–3000 years), although atmospheric sources eventually dominate pools of biologically available Sr in Hawaiian rainforests in older substrates (≥150,000 years). Received: 25 January 1999 / Accepted: 23 June 1999     

Organotin in the Tagus estuary

The tri(n-butyl)tin (TBT) moiety has been shown to have complex ecotoxicological effects on estuarine populations. In the Tagus the massive die-off of the Portuguese oyster (Crassostrea angulata Lmk), has been attributed to the introduction and use of this contaminant by shipyards. This paper reviews previous work by others and reassesses our results obtained in water and sediments of the Tagus estuary, as a contribution to the understanding of tin geochemistry and organotin speciation in this estuary. Contrary to earlier results, the latest surveys show that in the open waters of the Tagus measurable concentrations of all the three butyltin species occur, exhibiting peak concentrations at two locations that indicate two previously undetected sources of TBT. TBT also presents a peak concentration in sediments near the Lisnave shipyards, as previously suggested. The latest surveys still detected methylated forms of tin, particularly monomethyltin (Me Sn³⁺), in Tagus sediments, with maximum concentrations in the vicinity of urban effluent discharges. The concentrations for TBT and its degradation products found in the Tagus are potentially harmful to the populations of gastropods and endemic bivalves.     

Alginate-entrapped Haslea ostrearia as inoculum for the greening of oysters

Entrapment in calcium alginate beads of the marine diatom, Haslea ostrearia, was successfully used for stock-culture managment and afterwards the sowing of ponds for the greening of oysters. After storage during almost 2 months, viable and cultivable cells were recovered from beads by dissolving alginate matrix but an original way lies in directly introducing beads in ponds and promoting natural cell leakage. © Rapid Science Ltd. 1998     

Promoting effect of wood vinegar compounds on fruit-body formation ofPleurotus ostreatus

The promoting effect of wood vinegar compounds on the fruiting ofPleurotus ostreatus (Japanese name, Hiratake) was investigated. Not only crude wood vinegar but its components, 3,5-dimethylphenol, 2-methoxyphenol, butanoic acid and 1-pentanol, had the ability to promote fruit-body formation on liquid medium. For use of these promoters industrially, a test for practical cultivation was carried out using a commercial sawdust medium. The addition of 100 µg/ml butanoic acid and 100 µg/ml 2-methoxyphenol into the sawdust medium after removal of the surface mycelial layer (kinkaki in Japanese) produced 29 and 23% higher yields of fruit-bodies than the control cultures (137.2 g/bottle), respectively. The addition of the crude wood vinegar as a medium component into sawdust substrates in the concentration range of 0.1–6% increased yields of fruit-bodies by 21–42% over the control.