What Can Groundwater Monitoring Tell Us About Gas Migration? A Numerical Modeling Study

Groundwater monitoring to measure a variety of indicator parameters including dissolved gas concentrations, total dissolved gas pressure (TDGP), and redox indicators is commonly used to evaluate the impacts of gas migration (GM) from energy development in shallow aquifer systems. However, these parameters can be challenging to interpret due to complex free-phase gas source architecture, multicomponent partitioning, and biogeochemical reactions. A series of numerical simulations using a gas flow model and a reactive transport model were conducted to delineate the anticipated evolution of indicator parameters following GM in an aquifer under a variety of physical and biogeochemical conditions. The simulations illustrate how multicomponent mass transfer processes and biogeochemical reactions create unexpected spatial and temporal variations in several analytes. The results indicate that care must be taken when interpreting measured indicator parameters including dissolved hydrocarbon concentrations and TDGP, as the presence of dissolved gases in background groundwater and biogeochemical processes can cause potentially misleading conclusions about the impact of GM. Based on the consideration of multicomponent gas partitioning in this study, it is suggested that dissolved background gases such as N₂ and Ar can provide valuable insights on the presence, longevity and fate of free-phase natural gas in aquifer systems. Overall, these results contribute to developing a better understanding of indicators for GM in groundwater, which will aid the planning of future monitoring networks and subsequent data interpretation.     

Does CYP1A1polymophism increase the risk for cancer in pollution exposure? A study by gene ontology

Many genetic polymorphisms in metabolism enzymes are important for the risk of cancer as shown in a large number of case-control studies. Cytochrome P-450 (CYP) 1A1 polymorphism is a widely mentioned for importance of its genetic polymorphisms in risk assessment. However, the reports on the correlation between polymorphism and risk are inconsistent. To study the functional aberration in the human wild and mutate types of CYP1A1 is hard. Here, the author used a new gene ontology technology to predict the molecular function of human CYP1A1. Here, it can be seen that there is no functional difference between wild and mutate types of CYP1A1. Therefore, there should be no difference in effect of wild and mutate types of CYP1A1. This can support the null effect of this polymorphism in clinical findings of the population. This polymorphism might not be an important tool for risk assessment.     

Is the soil moisture precipitation feedback enhanced by heterogeneity and dry soils? A comparative study

The interaction between the land surface and the atmosphere is a crucial driver of atmospheric processes. Soil moisture and precipitation are key components in this feedback. Both variables are intertwined in a cycle, that is, the soil moisture – precipitation feedback for which involved processes and interactions are still discussed. In this study the soil moisture – precipitation feedback is compared for the sempiternal humid Ammer catchment in Southern Germany and for the semiarid to subhumid Sissili catchment in West Africa during the warm season, using precipitation datasets from the Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS), from the German Weather Service (REGNIE) and simulation datasets from the Weather Research and Forecasting (WRF) model and the hydrologically enhanced WRF-Hydro model. WRF and WRF-Hydro differ by their representation of terrestrial water flow. With this setup we want to investigate the strength, sign and variables involved in the soil moisture – precipitation feedback for these two regions. The normalized model spread between the two simulation results shows linkages between precipitation variability and diagnostic variables surface fluxes, moisture flux convergence above the surface and convective available potential energy in both study regions. The soil moisture – precipitation feedback is evaluated with a classification of soil moisture spatial heterogeneity based on the strength of the soil moisture gradients. This allows us to assess the impact of soil moisture anomalies on surface fluxes, moisture flux convergence, convective available potential energy and precipitation. In both regions the amount of precipitation generally increases with soil moisture spatial heterogeneity. For the Ammer region the soil moisture – precipitation feedback has a weak negative sign with more rain near drier patches while it has a positive signal for the Sissili region with more rain over wetter patches. At least for the observed moderate soil moisture values and the spatial scale of the Ammer region, the spatial variability of soil moisture is more important for surface-atmosphere interactions than the actual soil moisture content. Overall, we found that soil moisture heterogeneity can greatly affect the soil moisture – precipitation feedback.     

When were the walls of the Chauvet-Pont d'Arc Cave heated? A chronological approach by thermoluminescence

Direct chronological data of the ancient heating of calcitic walls at the Chauvet-Pont d'Arc Cave (Ardèche, France) were obtained at the Galerie des Mégacéros and at the Eboulis d'Entrée. Fragments of reddened limestone were extracted from the walls and were studied by thermoluminescence (TL). A novel measurement protocol of the equivalent dose (ED) was implemented and was optimized with respect to the nature of the material being dated (calcite), to the small quantities of sample available and to the relatively low heating of the rock surface in the past (close to 350 °C). The presence of a high level of free radon in the cave and ²¹⁰Pb in large excess in samples implied the development of a specific irradiation model allowing the evaluation of the mean annual dose over time, taking into account possible scenarios of radon and daughters migration from the bedrock. The following dating results were obtained (in ka before the present and associated total estimated standard deviation):- Galerie des Mégacéros, 36.9 ± 2.3 ka.- Eboulis d'Entrée, 34.3 ± 2.9 ka.These data are in agreement with the calibrated radiocarbon dates of the most ancient periods of human occupation in their respective areas. TL dates indicate that the fires which altered the walls were lighted during the first paleolithic human occupation period. Eventually, TL dating of the heated surface of the bedrock opens a new window on the chronology of human activities in the Chauvet-Pont d'Arc Cave and it makes an alternative contribution to the demonstration of the early chronology of its rock art.     

Are steroids really the cause for fish feminization? A mini-review of in vitro and in vivo guided TIEs

Feminization of fish has been reported throughout the world in freshwater and marine systems. While the population impacts are conflictive, enough negative effects warrant additional research into causation. In order to ascertain the identities of specific feminizing agents, variants of toxicity identification evaluations (TIEs) have been employed. The majority of these evaluations have utilized in vitro estrogen receptor-based cell-lines to identify chromatographic fractions that possess biological activity from predominately wastewater derived from municipal treatment facilities and have concluded that synthetic and natural estrogens are the primary cause for feminization of fish. This paper will focus on three aquatic systems impacted by wastewater originating from purely domestic, and industrial/domestic secondary treatment systems. Wastewater and sediment extracts were evaluated by in vitro and in vivo biological responses in a TIE fractionation design. While in vitro responses tended to mirror in vivo responses in purely domestic wastewater systems, in vitro responses tended to severely underestimate in vivo estrogenic activity when normalized to estradiol equivalents in more complex systems. TIE fractionation schemes using in vivo biological responses failed to indicate any relationship to steroids in either wastewater or sediment extractions. These data consistently support the view that mechanisms other than direct ER binding and activation by toxicants may be important in the feminization of fish particularly residing in habitats that receive complex wastewater or agricultural effluents.     

Are steroids really the cause for fish feminization? A mini-review of in vitro and in vivo guided TIEs

Feminization of fish has been reported throughout the world in freshwater and marine systems. While the population impacts are conflictive, enough negative effects warrant additional research into causation. In order to ascertain the identities of specific feminizing agents, variants of toxicity identification evaluations (TIEs) have been employed. The majority of these evaluations have utilized in vitro estrogen receptor-based cell-lines to identify chromatographic fractions that possess biological activity from predominately wastewater derived from municipal treatment facilities and have concluded that synthetic and natural estrogens are the primary cause for feminization of fish. This paper will focus on three aquatic systems impacted by wastewater originating from purely domestic, and industrial/domestic secondary treatment systems. Wastewater and sediment extracts were evaluated by in vitro and in vivo biological responses in a TIE fractionation design. While in vitro responses tended to mirror in vivo responses in purely domestic wastewater systems, in vitro responses tended to severely underestimate in vivo estrogenic activity when normalized to estradiol equivalents in more complex systems. TIE fractionation schemes using in vivo biological responses failed to indicate any relationship to steroids in either wastewater or sediment extractions. These data consistently support the view that mechanisms other than direct ER binding and activation by toxicants may be important in the feminization of fish particularly residing in habitats that receive complex wastewater or agricultural effluents.     

Are peatlands in different states with respect to their thermodynamic behaviour? A simple test of peatland energy and entropy budgets

Whilst all ecosystems must obey the second law of thermodynamics, these physical bounds and controls on ecosystem evolution and development are largely ignored across the ecohydrological literature. To unravel the importance of these underlying restraints on ecosystem form and function, and their power to inform our scientific understanding, we have calculated the entropy budget of a range of peat ecosystems. We hypothesize that less disturbed peatlands are ‘near equilibrium’ with respect to the second law of thermodynamics and thus respond to change by minimizing entropy production. This ‘near equilibrium’ state is best achieved by limiting evaporative losses. Alternatively, peatlands ‘far-from-equilibrium’ respond to a change in energy inputs by maximizing entropy production which is best achieved by increasing evapotranspiration. To test these alternatives this study examined the energy balance time series from seven peatlands across a disturbance gradient. We estimate the entropy budgets for each and determine how a change in net radiation (ΔR_n) was transferred to a change in latent heat flux (ΔλE). The study showed that: (i) The transfer of net radiation to latent heat differed significantly between peatlands. One group transferred up to 64% of the change in net radiation to a change in latent heat flux, while the second transferred as little as 27%. (ii) Sites that transferred the most energy to latent heat flux were those that produced the greatest entropy. The study shows that an ecosystem could be ‘near equilibrium’ rather than ‘far from equilibrium’.     

Are flat‐field snow depth measurements representative? A comparison of selected index sites with areal snow depth measurements at the small catchment scale

Single or a limited number of point observations, such as from index stations, are commonly assumed to be representative for the snow cover of larger areas in many applications. This study presents a systematic investigation of the relationship between point observations and areal mean snow depths ranging from the scale of tens of metres to entire catchments. We analyse aerial snow depth information from four mountain regions in the European Alps, one in the Spanish Pyrenees and one in the Canadian Rocky Mountains, obtained from airborne laser scanning surveys. This rich data set allowed to compare point values with snow cover statistics, reflecting the real snow depth distribution of the investigation areas. We present two contrasting approaches in order to assess the representativeness of typical flat‐field snow depth measurements. In the first approach, we define potential index stations based on topographic characteristics as commonly applied for snow cover monitoring stations. The point observations of these index stations are then compared with the mean values in their vicinities. We show that most of the index stations strongly overestimate the snow depth of the catchment and of their surrounding area at distances of several hundreds of metres. Results confirm the expectation that the larger the support area, the smaller the difference to the mean of the complete catchment. The second approach was to analyse topographic characteristics of all cells with snow depths that deviated less than 10% from the catchment mean. It appears that these representative cells are rather randomly distributed and cannot be identified a priori. In summary, our results show large potential biases of index stations with respect to snow distribution and therefore also snow water equivalent. Copyright © 2014 John Wiley & Sons, Ltd.     

Are spatial patterns of soil moisture at plot scales generalisable across catchments,climates, and other characteristics? A synthesis of synoptic soil moisture across the Mid-Atlantic

The spatial variation of soil moisture over very small areas (<100 m²) can have nonlinear impacts on cycling and flux rates resulting in bias if it is not considered, but measuring this variation is difficult over extensive temporal and spatial scales. Most studies examining spatial variation of soil moisture were conducted at hillslope (0.01 km²) to multi-catchment spatial scales (1000 km²). They found the greatest variation at mid wetness levels and the smallest variation at wet and dry wetness levels forming a concave down relationship. There is growing evidence that concave down relationships formed between spatial variation of soil moisture and average soil moisture are consistent across spatial scales spanning several orders of magnitude, but more research is needed at very small, plot scales (<100 m²). The goal of this study was to characterise spatial variation in shallow soil moisture at the plot scale by relating the mean of measurements collected in a plot to the standard deviation (SD). We combined data from a previous study with thousands of new soil moisture measurements from 212 plots in eight catchments distributed across the US Mid-Atlantic Region to (1) test for a generalisable mean–SD relationship at plot scales, (2) characterise how landcover, land use, season, and hillslope position contribute to differences in mean–SD relationships, and (3) use these generalised mean–SD relationships to quantify their impacts on catchment scale nitrification and denitrification potential. Our study found that 98% of all measurements formed a generalised mean–SD relationship like those observed at hillslope and catchment spatial scales. The remaining 2% of data comprised a mean–SD relationship with greater spatial variation that originated from two riparian plots reported in a previous study. Incorporating the generalised mean–SD relationship into estimates of nitrification and denitrification potential revealed strong bias that was even greater when incorporating mean–SD observations from the two riparian plots with significantly greater spatial variation.     

Does use of tropical beaches by tourists and island residents result in damage to fringing coral reefs? A case study in Moorea French Polynesia

Although coral reefs worldwide are subject to increasing global threats, humans also impact coral reefs directly through localized activities such as snorkeling, kayaking and fishing. We investigated five sites on the northern shore of Moorea, French Polynesia, and quantified the number of visitors on the beach and in shallow water. In field surveys, we measured total coral cover and colony sizes of two common genera, Porites and Acropora, a massive and branching morphology, respectively. One site, which hosted over an order of magnitude more people than the other four, had significantly less total coral cover and supported very little branching Acropora. In addition, size frequency distributions of both the branching and massive genera were skewed toward smaller colony sizes at the high use site. Our results demonstrated that the use of tropical beaches may result in less coral cover, with branching colonies rare and small.     

Scientific dialogue on climate: is it giving black eyes or opening closed eyes? Reply to “A black eye for the Hydrological Sciences Journal” by D. Huard

Citation Koutsoyiannis, D., Christofides, A., Efstratiadis, A., Anagnostopoulos, G.G. and Mamassis, N. (2011) Scientific dialogue on climate: is it giving black eyes or opening closed eyes? Reply to “A black eye for the Hydrological Sciences Journal” by D. Huard, Hydrol. Sci. J. 56(7), 1334–1339.     

Book Review: Monitoring the Comprehensive Nuclear-Test-Ban Treaty: Data Processing and Infrasound by Zoltan A. Der,Robert H. Shumway and Eugene T. Herrin (Eds.), Birkhäuser Verlag,Basel-Boston-Berlin, 2002, ISBN 3-7643-6676-1

Studia Geophysica et Geodaetica -     

Do long lived seabirds reduce the negative effects of acute pollution on adult survival by skipping breeding? A study with European storm petrels (Hydrobates pelagicus) during the "Prestige" oil-spill

We estimated the survival probability of breeding European storm petrels before, during and after a severe oil-spill. We hypothesized that petrels might have deserted the breeding colony to maximize their own survival probability and we expected no major change on adult survival probabilities as a consequence of the spill. We used an information-theoretical approach and multi-model inference to assess the strength of the evidence in favour of different hypotheses.Evidence contained in the data clearly supported the non-effect of the spill on adult survival hypothesis while punctual impact of the spill on survival and expanded (3 years) impact alternatives received less support. The effect size of the spill on averaged survival estimates was negligible in every case. We suggest that petrels minimized the impact of acute pollution by not investing in reproduction. We suggest that short-medium term management actions after oil-spills and similar catastrophes should focus on ecosystem restoration.     

Multiple interpretive errors? Indeed. Reply to: Climate effects of the 74 ka Toba super-eruption: Multiple interpretive errors in ‘A high-precision 40Ar/39Ar age for the Young Toba Tuff and dating of ultra-distal tephra’ by Michael Haslam

We would like to thank Michael Haslam (Haslam et al., 2013) for his interest in our recent contribution on the dating of the Young Toba Tuff/Tephra (YTT) (Mark et al., 2013). However, we point out errors made by Haslam, using this opportunity to clarify and expand on our discussion while also re-emphasising the important points from our study that have been overlooked.