A 520 year record of summer sunshine for the eastern European Alps based on stable carbon isotopes in larch tree rings

A 520-year stable carbon isotope chronology from tree ring cellulose in high altitude larch trees (Larix decidua Mill.), from the eastern European Alps, correlates more strongly with summer temperature than with summer sunshine hours. However, when instrumental records of temperature and sunshine diverge after AD1980, the tree ring time series does not follow warming summer temperatures but more closely tracks summer sunshine trends. When the tree ring stable carbon isotope record is used to reconstruct summer temperature the reconstruction is not robust. Reconstructed temperatures prior to the twentieth century are higher than regional instrumental records, and the evolution of temperature conflicts with other regional temperature reconstructions. It is concluded that sunshine is the dominant control on carbon isotope fractionation in these trees, via the influence of photosynthetic rate on the internal partial pressure of CO₂, and that high summer (July–August) sunshine hours is a suitable target for climate reconstruction. We thus present the first reconstruction of summer sunshine for the eastern Alps and compare it with the regional temperature evolution.     

Influence of tidal regime,diurnal phase,habitat and season on feeding of an intertidal crab

The relationship between diet and feeding activity of intertidal crabs, and environmental cycles (tidal, daily and seasonal), habitat and level of the intertidal zone (high/low) was studied using Neohelice granulata (Brachyura, Varunidae) as a model. This is a semi‐terrestrial burrowing crab occupying different habitats in the Southwestern Atlantic coasts and estuaries from bare low intertidal mudflats to high intertidal salt marshes, and from fine, organic matter rich sediment to very coarse sediment with low content of organic matter. The study was carried out in two contrasting habitats of three sites with diverse sets of physical and biological conditions. Diet and feeding of adult N. granulata were indirectly studied through the proportion of food items and the presence/absence of food in crab stomachs, respectively. This species has a dual mode of feeding: predominantly herbivorous (live plants or plant litter in salt marshes) or deposit feeder (superficial sediment and detritus in mudflats), but the quantity and quality of ingested food varies among habitats and sites. A trend to omnivory (including algae and conspecifics) was detected in relation to low quality of resources. Feeding activity modulated by a complex interaction of factors varied according to spatial and/or temporal changes in some natural cycles. Males and non‐ovigerous females fed preferably after dark and during submersion periods, but also after emersion periods if mudflat sediment remained wet; salt marsh crab feeding is somewhat independent of light and tidal cycles. Ovigerous females almost never fed. Both diet and feeding activity of this crab seem to be flexible traits adapted to different combinations of physical and biological factors.     

Evaluation of Methane Sources in Groundwater in Northeastern Pennsylvania

Testing of 1701 water wells in northeastern Pennsylvania shows that methane is ubiquitous in groundwater, with higher concentrations observed in valleys vs. upland areas and in association with calcium‐sodium‐bicarbonate, sodium‐bicarbonate, and sodium‐chloride rich waters—indicating that, on a regional scale, methane concentrations are best correlated to topographic and hydrogeologic features, rather than shale‐gas extraction. In addition, our assessment of isotopic and molecular analyses of hydrocarbon gases in the Dimock Township suggest that gases present in local water wells are most consistent with Middle and Upper Devonian gases sampled in the annular spaces of local gas wells, as opposed to Marcellus Production gas. Combined, these findings suggest that the methane concentrations in Susquehanna County water wells can be explained without the migration of Marcellus shale gas through fractures, an observation that has important implications for understanding the nature of risks associated with shale‐gas extraction.     

Local quasigeoid model creation from astrogeodetic measurements

This article describes the process of creation and testing of a local quasigeoid model using the astrogeodetic method known as astronomical levelling. The process used here was based on astronomical levelling principles combined with the least square adjustment in a triangular network and a common method of surface generation. Using this method, the authors have created a quasigeoid model of a small portion of the city of Brno. This model covers an area of approximately 1 × 2 km and is based on the astronomically determined vertical deflection at 11 stations. The average distance between the astrogeodetic stations was 500 m, which is an unusually high density (5.5 stations per km²). This high geo-spatial data density input made it possible to generate a quasigeoid model of height difference precision at mm-level over few km. Tests described in this article document the suitability of our methods for creating local quasigeoid models of high precision and resolution. Employing the least square adjustment in a planar network offers the possibility to easily compute standard deviations of both input and result values. This is a great advantage in comparison with more common astrogeodetic quasigeoid profiles, which are not suitable for simple adjustment and require more complex methods to be used for evaluation of their precision. The model described here serves the authors as a technological example, from which they learn more about the potential of the astrogeodetic method. Astrogeodetic models of a much greater extent are planned to be used for validation purposes of models generated by other independent methods (gravimetric, satellite, combined, etc.).     

The largest floods in the High Rhine basin since 1268 assessed from documentary and instrumental evidence

Abstract

The magnitudes of the largest known floods of the River Rhine in Basel since 1268 were assessed using a hydraulic model drawing on a set of pre-instrumental evidence and daily hydrological measurements from 1808. The pre-instrumental evidence, consisting of flood marks and documentary data describing extreme events with the customary reference to specific landmarks, was “calibrated” by comparing it with the instrumental series for the overlapping period between the two categories of evidence (1808–1900). Summer (JJA) floods were particularly frequent in the century between 1651–1750, when precipitation was also high. Severe winter (DJF) floods have not occurred since the late 19th century despite a significant increase in winter precipitation. Six catastrophic events involving a runoff greater than 6000 m ³ s^‐1 are documented prior to 1700. They were initiated by spells of torrential rainfall of up to 72 h (1480 event) and preceded by long periods of substantial precipitation that saturated the soils, and/or by abundant snowmelt. All except two (1999 and 2007) of the 43 identified severe events (SEs: defined as having runoff > 5000 and < 6000 m ³ s ^‐1) occurred prior to 1877. Not a single SE is documented from 1877 to 1998. The intermediate 121-year-long “flood disaster gap” is unique over the period since 1268. The effect of river regulations (1714 for the River Kander; 1877 for the River Aare) and the building of reservoirs in the 20th century upon peak runoff were investigated using a one-dimensional hydraulic flood-routing model. Results show that anthropogenic effects only partially account for the “flood disaster gap” suggesting that variations in climate should also be taken into account in explaining these features.

Citation Wetter, O., Pfister, C., Weingartner, R., Luterbacher, J., Reist, T., & Trösch, J. (2011) The largest floods in the High Rhine basin since 1268 assessed from documentary and instrumental evidence. Hydrol. Sci. J. 56(5), 733–758.     

The O’okiep Copper District, Namaqualand, South Africa: a review of the geology with emphasis on the petrogenesis of the cupriferous Koperberg Suite

The O’okiep Copper District is the oldest formal mining area in South Africa. Between 1852 and 2002, the 2,500 km² area yielded two million tons of copper from 32 mines ranging in ore tonnages from 140,000 to 37 million tons. This paper summarizes the calendar of events from the formation of the first primitive crust 1,700–2,000?Ma ago to early Cambrian times ~500?Ma ago, with particular emphasis on the Namaquan (Grenville) Orogeny, notably: the O’okiepian Episode (1,180–1,210?Ma ago) of alpine-type folding, regional granite plutonism, and granulite facies metamorphism and the Klondikean Episode (1,020–1,040?Ma ago) of open and tight folding and the intrusion of the Rietberg Granite and the Koperberg Suite. Almost all of the copper in the O’okiep District occurs in the Koperberg Suite, of which there are 1,700 small bodies that constitute 0.7% of the outcrop area. The suite comprises jotunite, anorthosite, biotite diorite, and hypersthenic rocks ranging from leuconorite to hypersthenite, and it is one of only two world examples of economic copper mineralization in rocks of the anorthosite–charnockite kindred; the second example is Caraiba, Brazil. High I _Sr and low ε _Nd (for a 1,030 Ma intrusion age), and high μ ₂ of 10.1, for Koperberg rock-types indicate a crustal progenitor for the suite, and the presence of jotunite suggests a (subducted) crustal source at ca. 40–50 km depth. The magmatic sulphide paragenesis in the Koperberg Suite is chalcopyrite?+?pyrrhotite (Narrap-type ore) that, in a number of ore-bodies, has been inverted under upper amphibolite facies conditions to bornite?+?Ti-free magnetite (Carolusberg-type ore). Meteoric fluids resulted in supergene Cu enrichment in Koperberg bodies to ~500?m below the pre-Nama peneplane, and lower greenschist facies metamorphism 500–570?Ma ago is reflected by inter alia Hoits-type ore bearing second-generation bornite?+?chalcopyrite(±?covellite?±?chalcocite).     

Seasonal variation in kangaroo tooth enamel oxygen and carbon isotopes in southern Australia

Serial sampling of tooth enamel growth increments for carbon and oxygen isotopic analyses of Macropus (kangaroo) teeth was performed to assess the potential for reconstructing paleoseasonality. The carbon isotope composition of tooth enamel apatite carbonate reflects the proportional intake of C₃ and C₄ vegetation. The oxygen isotopic composition of enamel reflects that of ingested and metabolic water. Tooth enamel forms sequentially from the tip of the crown to the base, so dietary and environmental changes during the tooth's formation can be detected. δ¹³C and δ¹⁸O values were determined for a series of enamel samples drilled from the 3rd and 4th molars of kangaroos that were collected along a 900 km north–south transect in southern Australia. The serial sampling method did not yield pronounced seasonal isotopic variation patterns in Macropus enamel. The full extent of dietary isotopic variation may be obscured by attenuation of the isotopic signal during enamel mineralisation. Brachydont (low-crowned) Macropus teeth may be less sensitive to seasonal variation in isotopic composition due to time-averaging during mineralisation. However, geographic variations observed suggest that there may be potential for tracking latitudinal shifts in vegetation zones and seasonal environmental patterns in response to climate change.     

Questioning the virtues of pro-environmental behaviour research: Towards a phronetic approach

Drawing on Flyvbjerg’s (2001) call for the development of phronetic social science, this paper argues that much current research into pro-environmental behaviour (PEB) is misguided, and even potentially dangerous. After outlining Flyvbjerg’s argument, it reviews existing work on PEB and argues that, to date, it has predominantly sought after the Aristotelian intellectual virtues of either episteme or techne, and has neglected phronesis which Aristotle himself saw as most important. It then explores the ways in which aspects of a phronetic approach are being developed in cultural geography and environmental sociology, before offering a brief empirical case study of a PEB-change initiative to illustrate what a phronetic approach to research might look like. It concludes by calling for an improved and more reflexive dialogue between PEB researchers regarding the purpose and approach of their work, both in order to improve the relevance and impact of their research, and in order to help individuals and communities understand and confront the significant environmental challenges they currently face.