Reuniting the “head hunted” Corythosaurus excavatus (Dinosauria: Hadrosauridae) holotype skull with its dentary and postcranium

A Corythosaurus skull (UALVP 13) was collected in 1920 from what is now Dinosaur Provincial Park in southern Alberta, Canada and was designated the holotype of Corythosaurus excavatus, a new hadrosaur species by Gilmore (1923). In 1992, a previously uncovered, weathered, headless skeleton was found. This was collected in 2012 by the University of Alberta as there was potential it could belong to the holotype skull. In addition, an isolated hadrosaur dentary had been found in 1992 close to the articulated postcranial skeleton and may be one of the missing jaws of Corythosaurus excavatus. The hypothesis that it may be the skeleton of the holotype of Corythosaurus excavatus is tested using anatomical information and statistical analyses. Statistical comparisons suggest it is possible that the skull and dentary belong to the same specimen. Furthermore, bivariate plots and percentage prediction errors also indicate that the postcranial material could belong to the UALVP 13 skull. Because many large vertebrate fossil specimens (even types) are not always collected in their entirety, this method may be used as a line of evidence to determine whether independently collected specimens potentially belong to the same individual. The problems described herein highlight the need to collect specimens in their entirety, and for good field documentation, including the spatial and stratigraphic context of all finds.     

Seasonal dynamics and production of the hydromedusan Clytia hemisphaerica (Hydromedusa: Leptomedusa) in Southampton water

In 1990 and 1991, a zooplankton sampling program revealed the presence of the hydromedusan Clytia hemisphaerica (Hydromedusa: Leptomedusa) from early May through late September throughout Southampton Water. The most notable aspects of the population dynamics of C. hemisphaerica in Southampton Water were the considerable interannual variation in peak abundance—10.65 m^?3 in 1990 and 2.44 m^?3 in 1991—and temporal patterns of mean bell diameter. The suggestion of almost continuous reproduction in 1990, as indicated by high abundance and large size range on each sampling date, is in contrast to 1991, where at the Cracknore site, five cohorts were produced at 21 d to 80 d intervals. The maximum bell diameter attained in each generation was typically 10–11 mm. At the Cracknore site in 1991, in situ bell diameter growth was linear within each cohort. A trend of increased growth rate with each subsequent cohort, from 26 μg DW d^?1 to 106 μg DW d^?1 was coincident with increasing water temperature. Annual production ranged from 0.98 mg C m^?3 yr^?1 to 1.08 mg C m^?3 yr^?1 in 1990 and 0.35 mg C m^?3 yr ^?1 to 0.48 mg C m^?3 yr^?1 in 1991. Daily P: B ratios varied in each cohort from 0.05 to 0.35.     

Mediterranean Seagrass Growth and Demography Responses to Experimental Warming

We experimentally examined the effects of increased temperature on growth and demography of two Mediterranean seagrasses Posidonia oceanica and Cymodocea nodosa. Shoots of C. nodosa and seedlings and shoots of P. oceanica were kept in mesocosms for 3?months and exposed to temperatures between 25 and 32?°C encompassing the range of maximum summer seawater temperatures projected for the Mediterranean Sea during the twenty-first century. The response of P. oceanica seedlings to warming was evident with reduced growth rates, leaf formation rates and leaf biomass per shoot. Younger life stages of P. oceanica may therefore be particularly vulnerable to climate change and warming. Leaf formation rates in the shoots of P. oceanica declined with increasing temperature and the lowest population growth (?0.005?day^?1) was found at 32?°C. Temperature effects on C. nodosa were variable. Rhizome growth increased with warming (0.07?C0.09?cm?day^?1?°C of warming), whereas other indicators of plant performance (aboveground/belowground biomass, leaf biomass and population growth) appeared to be stimulated by increased temperature to a threshold temperature of around 29?C30?°C beyond which they declined. P. oceanica and C. nodosa are likely to be negatively impacted by the effects of global warming over the next century and climate change poses a significant challenge to seagrasses and may stress these key habitat-forming species that are already suffering losses from anthropogenic impacts.     

Detoxification of chlorinated sewage effluent by dechlorination in estuarine waters

Secondary treated sewage was chlorinated to a residual level of 2–10 mg/l in a continuous flow system in the laboratory and diluted to various levels with estuarine water. A portion of the chlorinated sewage effluent was dechlorinated with sodium thiosulfate and the dechlorinated waste was diluted with estuarine water in the same proportions as the chlorinated waste.Menidia menidia, Palaemonetes pugio andCrassostrea virginica were exposed to chlorinated and dechlorinated treatments. High concentrations of chlorinated effluent caused mortalities inM. menidia andP. pugio, whereas similar concentrations of dechlorinated wastes did not cause mortalities. Mortalities in the chlorinated waste are correlated with chlorine residuals. Similarly, the chlorinated wastes depressed the shell deposition rate ofC. virginica below 50% of controls at all doses. Dechlorinated waste allowed shell deposition greater than 50% of controls. However, the occurrence of some growth inhibition inC. virginica exposed to dechlorinated waste suggests the presence of toxic material in the waste other than chlorine.     

Upwelling, species, and depth effects on coral skeletal cadmium-to-calcium ratios (Cd/Ca)

Skeletal cadmium-to-calcium (Cd/Ca) ratios in hermatypic stony corals have been used to reconstruct changes in upwelling over time, yet there has not been a systematic evaluation of this tracer’s natural variability within and among coral species, between depths and across environmental conditions. Here, coral skeletal Cd/Ca ratios were measured in multiple colonies of Pavona clavus, Pavona gigantea and Porites lobata reared at two depths (1 and 7 m) during both upwelling and nonupwelling intervals in the Gulf of Panama (Pacific). Overall, skeletal Cd/Ca ratios were significantly higher during upwelling than during nonupwelling, in shallow than in deep corals, and in both species of Pavona than in P. lobata. P. lobata skeletal Cd/Ca ratios were uniformly low compared to those in the other species, with no significant differences between upwelling and nonupwelling values. Among colonies of the same species, skeletal Cd/Ca ratios were always higher in all shallow P. gigantea colonies during upwelling compared to nonupwelling, though the magnitude of the increase varied among colonies. For P. lobata, P. clavus and deep P. gigantea, changes in skeletal Cd/Ca ratios were not consistent among all colonies, with some colonies having lower ratios during upwelling than during nonupwelling. No statistically significant relationships were found between skeletal Cd/Ca ratios and maximum linear skeletal extension, δ¹³C or δ¹⁸O, suggesting that at seasonal resolution the Cd/Ca signal was decoupled from growth rate, coral metabolism, and ocean temperature and salinity, respectively. These results led to the following conclusions, (1) coral skeletal Cd/Ca ratios are independent of skeletal extension, coral metabolism and ambient temperature/salinity, (2) shallow P. gigantea is the most reliable species for paleoupwelling reconstruction and (3) the average Cd/Ca record of several colonies, rather than of a single coral, is needed to reliably reconstruct paleoupwelling events.     

Isotopic partitioning between scallop shell calcite and seawater: effect of shell growth rate

The relationship between molluscan shell growth rate and skeletal δ¹⁸O and δ¹³C was investigated in a detailed field study for the scallop, Pecten maximus. Seasonal variation in shell growth rate was found to be a governing factor influencing shell δ¹⁸O and δ¹³C. At low shell growth rates, shell δ¹⁸O were more positive (of the order +0.4‰) and δ¹³C more negative (up to −2‰) as compared with predicted values for precipitation of inorganic calcite in isotopic equilibrium with seawater. The deviations in δ¹⁸O were hypothesized as reflecting possible differences in solution carbonate chemistry at the site of mineralization in the extrapallial fluid as compared with that of the external seawater medium. The deviations in shell δ¹³C were consistent with incorporation of isotopically depleted respiratory ¹³C (i.e., a metabolic effect). A trend toward more depleted shell δ¹⁸O and δ¹³C values occurred at higher shell growth rates, with negative δ¹⁸O values as compared with predicted equilibrium at shell growth rates above 0.13 mm per day. These simultaneous negative deviations in skeletal δ¹⁸O and δ¹³C were interpreted as resulting from a kinetic effect. The implications for environmental reconstruction from molluscan isotopic records are discussed in light of a model of isotopic behavior based on the findings of the study.     

Comparison of the effects of conventional organic amendments and biochar on the chemical, physical and microbial properties of coal fly ash as a plant growth medium

The bulk of fly ash (an inorganic waste of coal-fired power generation) produced is deposited in disposal areas where it needs to be revegetated. The effects of addition of three conventional organic amendments (biosolids, poultry manure, green waste compost), or poultry manure-derived biochar, to coal fly ash (at two rates) on some key chemical, physical and microbial properties and on growth of Rhodes grass (Chloris gayana) was studied in a laboratory incubation/greenhouse study. Addition of all amendments, including biochar, increased concentrations of extractable Mg, K, Na and P and CEC_{(pH 7.0)}. Additions of poultry manure, and particularly biosolids, also greatly increased levels of extractable NH₄ ⁺ and NO₃ ⁻-N. Addition of biosolids, green waste compost and biochar resulted in a decrease in macroporosity, a concomitant increase in mesoporosity and, at the high rate of addition, an increase in available water-holding capacity. Basal respiration was very low in fly ash and was increased by addition of all amendments; metabolic quotient was markedly greater in control than amended treatments. Biosolids, poultry manure and green waste compost additions all increased microbial biomass C. Growth of Rhodes grass was extremely low under unfertilized conditions in control, biochar and, to a lesser extent, green waste compost treatments but addition of poultry manure and the lower rate of biosolids resulted in large increases in yields. Although biochar additions increased extractable Ca, K, P, Cu, Zn and Mn, CEC, mesoporosity and water-holding capacity, they had a little or no stimulatory effect on the size of the soil microbial community, N fertility or plant growth. This was attributable to the lack of metabolisable C and an insignificant N-supplying capacity.     

Biodegradation of starch blended polyvinyl chloride films by isolated Phanerochaete chrysosporium PV1

The accumulation of plastics in the environment is raising great concerns with respect to long-term environmental, economic and waste management problems. The aim of the present research was to investigate the biodegradability of starch blended polyvinyl chloride films in soil burial and controlled laboratory experiments using selective fungal isolates. Clear surface aberrations as color change and minor disintegration in polyvinyl chloride films were observed after 90 days and later confirmed through scanning electron microscopy. The fungal strains showing prominent growth and adherence on plastic films were isolated. One of the strains showing maximum activity was selected and identified as Phanerochaete chrysosporium PV1 by rDNA sequencing. Fourier transform infrared spectroscopy and nuclear magnetic resonance analyses indicated considerable structural changes and transformation in films in terms of appearance of new peaks at 3,077 cm^?1 (corresponding to alkenes) and decrease in intensity of peaks at 2,911 cm^?1 (C–H stretching). It was supported with a significant decrease in the molecular weight of polymer film from 80,275 to 78,866 Da (treated) through Gel permeation chromatography in shake flask experiment. Moreover, the biodegradation of starch blended polyvinyl chloride films was confirmed through release of higher CO₂ (7.85 g/l) compared to control (2.32 g/l) in respirometric method. So fungal strain P. chrysosporium PV1 has great potential for use in bioremediation of plastic waste.     

The mineralogic transformation of ferrihydrite induced by heterogeneous reaction with bioreduced anthraquinone disulfonate (AQDS) and the role of phosphate

Bioreduced anthraquinone-2,6-disulfonate (AH₂DS; dihydro-anthraquinone) was reacted with a 2-line, Si-substituted ferrihydrite under anoxic conditions at neutral pH in PIPES buffer. Phosphate (P) and bicarbonate (C); common adsorptive oxyanions and media/buffer components known to effect ferrihydrite mineralization; and Fe(II)_aq (as a catalytic mineralization agent) were used in comparative experiments. Heterogeneous AH₂DS oxidation coupled with Fe(III) reduction occurred within 0.13-1 day, with mineralogic transformation occurring thereafter. The product suite included lepidocrocite, goethite, and/or magnetite, with proportions varing with reductant:oxidant ratio (r:o) and the presence of P or C. Lepidocrocite was the primary product at low r:o in the absence of P or C, with evidence for multiple formation pathways. Phosphate inhibited reductive recrystallization, while C promoted goethite formation. Stoichiometric magnetite was the sole product at higher r:o in the absence and presence of P. Lepidocrocite was the primary mineralization product in the Fe(II)_aq system, with magnetite observed at near equal amounts when Fe(II) was high [Fe(II)/Fe(III)] = 0.5 and P was absent. P had a greater effect on reductive mineralization in the Fe(II)_aq system, while AQDS was more effective than Fe(II)_aq in promoting magnetite formation. The mineral products of the direct AH₂DS-driven reductive reaction are different from those observed in AH₂DS-ferrihydite systems with metal reducing bacteria, particularly in presence of P.     

The growth of submersed macrophytes under experimental salinity and light conditions

The growth, morphology, and chemical composition ofHydrilla verticillata, Myriophyllum spicatum, Potamogeton perfoliatus, andVallisneria americana were compared among different salinity and light conditions. Plants were grown in microcosms (1.2 m⁵) under ambient photoperiod adjusted to 50% and 8% of solar radiation. The culture solution in five pairs of tanks was gradually adjusted to salinities of 0, 2, 4, 6, and 12‰. With the exception ofH. verticillata, the aquatic macrophytes examined may be considered eurysaline species that are able to adapt to salinities one-third the strength of sea water. With increasing salinity, the inflorescence production decreased inM. spicatum andP. perfoliatus, yet asexual reproduction in the latter species by underground buds remained constant. Stem elongation increased in response to shading inM. spicatum, while shadedP. perfoliatus had higher concentrations of chlorophylla. In association with high epiphytic mass, chlorophylla concentrations in all species were greatest at 12‰. The concentration of sodium increased in all four species of aquatic macrophytes examined here, indicating that these macrophytes did not possess mechanisms to exclude this ion. The nitrogen content (Y) of the aquatic macrophytes tested increased significantly with higher sodium concentration (X), suggesting that nitrogen may be utilized in osmoregulation (Y = X × 0.288 + 6.10, r² = 0.71). The tolerance ofV. americana andP. perfoliatus to salinity was greater in our study compared to other investigations. This may be associated with experimental methodology, whereby macrophytes were subjected to more gradual rather than abrupt changes in salinity. The two macrophytes best adapted to estuarine conditions in this study by exhibiting growth up to 12‰, includingM. spicatum andV. americana, also exhibited a greater degree of response in morphology, tissue chemistry (including chlorophyll content and total nitrogen), and reproductive output in response to varying salinity and light conditions.     

The chemical composition of surface water in the influence zone of the Severonikel smelter

This paper reports data on the chemical composition of surface waters (predominant ions and trace elements: approximately 40 parameters and elements) in the influence zone of the Severonikel Cu-Ni smelter in the town of Monchegorsk, Murmansk oblast. The long-continued discharge of waste waters has increased the mineralization and changed the proportions of ions in surface waters in the area: water in the sewage pond of the smelter is classed with brackish waters of the S ₄ ^2? class, Na⁺ group. The sequence of major ions in water bodies under aerotechnogenic load retains the natural succession of major cations, but their concentrations slightly increase. The maximum concentration of ions in the surface waters of the Monchegorsk testing area were detected in wintertime, and the minimum contents occur during the high water period. Water bodies under aerotechnogenic load are characterized by average mineralization values much higher than is natural. The highest concentrations of Ni and Cu (two to three orders of magnitude higher than the assumed background values) and practically all trace elements were found in water bodies receiving waste waters from the smelter. The concentrations of Ni and other heavy metals in the Moncha River are much lower than in other water bodies but more than one order of magnitude higher than the assumed background concentrations.     

The autecology and production dynamics of eelgrass (Zostera marina L.) in Netarts Bay,Oregon

Changes in biomass, growth form and shoot net primary production in an eelgrass, Zostera marina L., bed were monitored along transects at three tidal heights in Netarts Bay, Oregon, from May 1979 through June 1981. During the growing season, April through October, the mean plastochrone interval was 16.5 d along the low intertidal transect and 11.6 d along the high intertidal transect. The mean export interval was 13.3 d along the low intertidal transect and 11.6 d along the high intertidal transect. The life span of a leaf averaged 48 d along the low intertidal transect and 36 d along the high intertidal transect. Shoot density was positively correlated with mean leaf area index (LAI) until the LAI reached 3.8 to 5.5, above which LAI was negatively correlated with density. The maximum Zostera biomass ranged from 143 (high intertidal transect) to 463 (low intertidal transect) g dry wt m^?2. Maximum values of shoot net production ranged from 4.7 (high intertidal transect) to 13.6 (low intertidal transect) g dry wt m^?2d^?1. Zostera shoot net production was related to light and to the physical damage to the shoots associated with a rapid accumulation of Enteromorpha biomass in the bay. In addition, patterns of biomass accumulation were related to the duration of water coverage, as determined by both tidal height and local impoundments of water. At all transects, biomass sloughed was equal to at least 50% of the shoot net primary production in that area during that time period; sloughed leaves accounted for 25 to 97% of these losses. An estimate of the total annual net primary production of aboveground Zostera in the bed was 17,500 kg, dry wt (SE=3,080 kg dry wt), which was equivalent to a mean annual rate of 383 g C m^?2 (SE=67 g C m^?2)     

Growth and Cu accumulation by plants grown on Cu containing mine tailings in Cyprus

The Skouriotissa Cu mine in the northern part of Cyprus has produced large amounts of mine waste. Phytoremediation could stabilise the erosion or extract the metals of this waste. The aim of this study was to find out if Pistacia terebinthus, Cistus creticus, Pinus brutia and/or Bosea cypria could grow and tolerate or maybe accumulate Cu from the mine waste containing up to 787 mg Cu (kg DW)⁻¹. Another aim was to see if the liquid wine waste product Vinassa, containing organic acids and having a low pH, or chicken fertilizer could improve plant growth and/or Cu accumulation. The four species were planted at the mine waste site untreated or with the addition of Vinassa or chicken fertilizer as mine waste modifiers. After 3 months, shoot length growth was measured and the plants were analysed for Cu concentration. The pH and Cu concentration of the mine waste mixture in the different treatments was also measured. To find out if plants accumulated Cu to the highest extent in roots or shoot, a greenhouse study was undertaken where the plant species were cultivated for 3 weeks in Cu spiked soil. The results showed that all of the tested species survived and grew on the mine waste site, which indicates that they tolerate the high level of Cu at the mine waste site. The leaves of C. creticus had the highest Cu accumulation of all tested species. Copper accumulation varied with plant species. They seemed to have different distribution strategies for Cu: in Pistacia terebinthus and C. creticus most of the Cu was found in the roots, while B. cypria accumulated most of the Cu in the leaves. Addition of Vinassa and chicken fertilizer did not increase plant growth or Cu accumulation, but did affect the Cu distribution in B. cypria.     

Phosphorus Budget of the Sundarban Mangrove Ecosystem: Box Model Approach

Phosphorus (P) cycling in mangroves plays an important role in productivity but the magnitude of atmospheric input in the mangrove P budget is still uncertain. This study applied a box model approach to assess P budget in the Indian Sundarban, the world’s largest mangrove ecosystem for conceptual understanding of P cycling and for better representation of transport and transformation of P within the mangrove ecosystem. The P content in the sediment (0.19–0.67 μg g^?1) was found much below its maximum retention capacity (322 μg g^?1) and was lower than the mean marine sediment (669 μg g^?1). The C:N and C:P ratios were correlated (r ² = 0.66, P < 0.01) and the major fraction of available P was recycled within the organic structure of mangrove ecosystem, thus maintaining productivity through conservation strategies. Atmospheric input accounted for 56.7% of total P input (16.06 Gg year^?1) and 50% of total P output (14.7 Gg year^?1) was attributed to plant uptake. Budget closing or unaccounted P (1.36 Gg) was only 8.5% of the total input. Two feedback pathways, i.e., input of P from dust fallout and biochemical mineralization of organic matter, significantly affected P availability. The findings of the study suggest that atmospheric deposition is of major importance as a natural and/or anthropogenic forcing function in the Sundarban mangrove system.     

Kinetic rate laws as derived from order parameter theory II: Interpretation of experimental data by laplace-transformation,the relaxation spectrum,and kinetic gradient coupling between two order parameters

A unifying theory of kinetic rate laws, based on order parameter theory, is presented. The time evolution of the average order parameter is described by $$\langle Q\rangle \propto \smallint P(x)e^{^{^{^{^{^{^{ - xt} } } } } } } dx = L(P)$$ where t is the time, x is the effective inverse susceptibility, and L indicates the Laplace transformation. The probability function P(x) can be determined from experimental data by inverse Laplace transformation. Five models are presented:

1. Polynomial distributions of P(x) lead to Taylor expansions of 〈Q〉 as $$\langle Q\rangle = \frac{{\rho _1 }}{t} + \frac{{\rho _2 }}{{t^2 }} + ...$$
2. Gaussian distributions (e.g. due to defects) lead to a rate law $$\langle Q\rangle = e^{ - x_0 t} e^{^{^{^{^{\frac{1}{2}\Gamma t^2 } } } } } erfc\left( {\sqrt {\frac{\Gamma }{2}} t} \right)$$ where x ₀ is the most probable inverse time constant, Γ is the Gaussian line width and erfc is the complement error integral.
3. Maxwell distributions of P are equivalent to the rate law 〈Q〉∝e^?k√t .
4. Pseudo spin glasses possess a logarithmic rate law 〈Q〉∝lnt.
5. Power laws with P(x)=x ^a lead to a rate law: ln〈Q〉=-(α + 1) ln t.

The power spectra of Q are shown for Gaussian distributions and pseudo spin glasses. The mechanism of kinetic gradient coupling between two order parameters is evaluated.     

Preferred orientation in experimentally deformed dolomite

Fine grained dolomite has been deformed in over twenty compression experiments in a Griggs-type piston-cylinder apparatus at various P and T conditions. Preferred orientation determined quantitatively using X-ray techniques and spherical harmonic analysis of the data is presented in inverse pole-figures of — 2/m symmetry. In most cases specimens display strong preferred orientation which varies mainly as a function of temperature. At all conditions it is very different from calcitic limestone. Although there is no significant grain growth even at 1000 °C the simple c-axes maximum fabric above 700 °C might be the result of recrystallization or translation on c. Below 700 °C, the preferred orientation is much weaker and complex. The primary maximum in the inverse pole-figure is near e, a secondary maximum near a high angle positive rhomb, principal minima are at c and f. This inverse pole-figure is consistent with f-twinning and translation gliding on r (t = a ?), two mechanisms which counteract each other. The latter is a new deformation mechanism for dolomite which we propose in order to explain the pattern of preferred orientation. The minimum at c is less pronounced below 100 ° C suggesting that c-translation may be active, but in these fine-grained aggregates it appears to be less important than is expected from single crystal experiments (Higgs and Handin, 1959), at least at low temperatures.     

Stabilization of extracellular polymeric substances (Bacillus subtilis) by adsorption to and coprecipitation with Al forms

Extracellular polymeric substances (EPS) are continuously produced by bacteria during their growth and metabolism. In soils, EPS are bound to cell surfaces, associated with biofilms, or released into solution where they can react with other solutes and soil particle surfaces. If such reaction results in a decrease in EPS bioaccessibility, it may contribute to stabilization of microbial-derived organic carbon (OC) in soil. Here we examined: (i) the chemical fractionation of EPS produced by a common Gram positive soil bacterial strain (Bacillus subtilis) during reaction with dissolved and colloidal Al species and (ii) the resulting stabilization against desorption and microbial decay by the respective coprecipitation (with dissolved Al) and adsorption (with Al(OH)_3(am)) processes. Coprecipitates and adsorption complexes obtained following EPS-Al reaction as a function of pH and ionic strength were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The stability of adsorbed and coprecipitated EPS against biodegradation was assessed by mineralization experiments for 1100 h. Up to 60% of the initial 100 mg/L EPS-C was adsorbed at the highest initial molar Al:C ratio (1.86), but this still resulted only in a moderate OC mass fraction in the solid phase (17 mg/g Al(OH)_3(am)). In contrast, while coprecipitation by Al was less efficient in removing EPS from solution (maximum values of 33% at molar Al:C ratios of 0.1-0.2), the OC mass fraction in the solid product was substantially larger than that in adsorption complexes. Organic P compounds were preferentially bound during both adsorption and coprecipitation. Data are consistent with strong ligand exchange of EPS phosphoryl groups during adsorption to Al(OH)_3(am), whereas for coprecipitation weaker sorption mechanisms are also involved. X-ray photoelectron analyses indicate an intimate mixing of EPS with Al in the coprecipitates, which is not observed in the case of EPS adsorption complexes. The incubation experiments showed that both processes result in overall stabilization of EPS against microbial decay. Stabilization of adsorbed or coprecipitated EPS increased with increasing molar Al:C ratio and biodegradation was correlated with EPS desorption, implying that detachment of EPS from surface sites is a prerequisite for microbial utilization. Results indicate that the mechanisms transferring EPS into Al-organic associations may significantly affect the composition and stability of biomolecular C, N and P in soils. The observed efficient stabilization of EPS might explain the strong microbial character of organic matter in subsoils.     

Biogeochemical studies of areas of sulphide mineralization in Northern Greece

Biogeochemical and geobotanical studies have been carried out in several areas of sulphide mineralization in northern Greece. In porphyry copper areas, mineralized zones can be delineated by mapping the distribution of Minuartia verna, or by measuring the copper content of Rumex acetosella and Thymus sibthorpii. Elevated levels of molybdenum in the soil are indicated by higher concentrations of this element in T. sibthorpii. In an area of barite mineralization, biogeochemical methods were not useful in showing the barium distribution, but did provide an indication of the associated lead mineralization. The appearance of the nickel accumulator Alyssum murale near a zone of antimonite mineralization seems to be related to sporadic occurrences of ultrabasic rocks nearby.     

The coprecipitation of Sr into calcite precipitates induced by bacterial ureolysis in artificial groundwater: Temperature and kinetic dependence

A suite of experiments was performed to investigate the partitioning of Sr²⁺ (to mimic the radionuclide ⁹⁰Sr) between calcite and artificial groundwater in response to the hydrolysis of urea (ureolysis) by Bacillus pasteurii under simulated in situ aquifer conditions. Experiments were performed at 10, 15, and 20°C over 7 days in microcosms inoculated with B. pasteurii ATCC 11859, containing an artificial groundwater and urea (AGW) or an AGW including a Sr contaminant treatment. During the experiments, the concentration of ammonium generated by bacterial ureolysis increased asymptotically, and derived rate constants (k_urea) that were between 13 and 10 times greater at 20°C than at 15 and 10°C. Calcite precipitation was initiated after similar amounts of urea had been hydrolyzed (∼ 4.0 mmol L^-1) and a similar critical saturation state (mean S_critical = 53, variation = 20%) had been reached, independent of temperature and Sr treatment. Because of the positive relationship between the rate of ureolysis and temperature, precipitation began by the end of day 1 at 20°C, and between days 1 and 2 at 15 and 10°C. The rate of calcite precipitation increased with, and was fundamentally controlled by calcite saturation state (S), irrespective of temperature. The presence of Sr slightly slowed calcite precipitation rates at equivalent values of S, which may reflect the screening of active nucleation and crystal growth sites by Sr. Homogeneous partitioning coefficients (D_Sr) exhibited a positive association with calcite precipitation rates, but were greater at higher experimental temperatures at equivalent precipitation rates (20°C mean = 0.46; 15°C mean = 0.24; 10°C mean = 0.29).     

Comparative growth of juvenile white sturgeon and striped bass: Effects of temperature and hypoxia

The influences of temperature and environmental hypoxia on the growth rates of two California anadromous fishes, white sturgeon (Acipenser transmontanus) and striped bass (Morone saxatilis) were examined. Fish (0.5–0.6 g initial weight) were fedad libitum rations ofArtemia in flow-through aquaria regulated for temperature (15, 20, and 25°C) and oxygen tension (130 and 90 torr P_{o 2}). Growth of sturgeon was significantly greater at 20 °C compared with 15 °C, but there was no difference between 20 and 25 °C. Striped bass growth increased with each 5° increment of temeprature elevation to 3.2% body weight per d at 25 °C, the fastest growth rate measured. The temperature of maximum growth reflected the temperature of the native estuarine rearing area. Environmental hypoxia (90 torr P_{o 2}) reduced growth of sturgeon within each temperature level, whereas striped bass growth was reduced by hypoxia only at the upper two temperatures. Sturgeon were much more active in the growth chambers than striped bass. Sturgeon activity increased with each 5 °C temperature increase under normoxia and hypoxia, except at 25 °C (hypoxia) where activity was insignificantly different from that at 20 °C (hypoxia).