Carbon quantity defines productivity while its quality defines community composition of bacterioplankton in subarctic ponds

Bacterial communities in 16 oligotrophic ponds in Kilpisj?rvi, subarctic Finland, were studied to test the hypothesis that dissolved organic carbon (DOC) quantity and quality differently influence bacterioplankton. The ponds were located below and above treeline at 600?m a.s.l., with 2?C4 fold higher concentration of DOC below treeline. The concentration of DOC changed during the open-water season with highest values measured in mid-summer. Bacterial production, abundance, biomass were highest in mid-summer and correlated positively with the concentration of DOC. Quality indices of DOC showed that spring differed from the rest of the season. Highest specific UV-absorbance (SUVA) and humification index (HI), ratio a250/a265 and lowest fluorescence index (FI) were found during spring compared to summer and autumn, possibly indicating higher relative importance of allochthonous carbon during spring and a seasonal effect of photo-oxidation. According to Length Heterogeneity Polymerase Chain Reaction (LH-PCR) analyses, bacterial communities in spring were significantly different from those later in the season, possible due to the introduction of terrestrial bacteria associated with higher molecular weight material in spring DOC. Comparison between ponds situated above and below treeline revealed that bacteria were more abundant and productive at lower altitudes, which is probably connected to higher concentrations of DOC. The results also suggest that increased temperature and precipitation induced by global change and consequent higher allochthonous DOC runoff from the catchment could have a strong impact on biomass, productivity and community composition of micro-organisms in subarctic ponds and lakes.     

Early Archean spherule layers from the Barberton Greenstone Belt,South Africa: Mineralogy and geochemistry of the spherule beds in the CT3 drill core

Little is known about the Hadean and the Archean impact record on Earth. In the CT3 drill core from the Fig Tree Group of the northern Barberton Greenstone Belt, 17 spherule layer intersections occur, which, provide an outstanding new opportunity to gain insights into meteorite bombardment of the early Earth. CT3 spherules, as primary features, mostly exhibit textural patterns similar to those of the other Barberton spherule layers, but locally mineralogical and chemical compositional differences are observed, likely as a result of various degrees of alteration. The observed mineralogy of the spherule layers is of secondary origin and comprises K‐feldspar, phyllosilicates, carbonates, sulfides, and oxides, with the exception of secondary Ni‐Cr spinel that is of primary origin. Our petrographic investigations suggest alteration by K‐metasomatism, sericitization, silicification, and carbonatization. Siderophile element contents of bulk samples show significant enrichments in Ni (up to 2 wt%) and Ir (up to ~3 ppm), similar to previously studied Archean spherule layers. These values are indicative of the presence of a meteoritic component. On the other hand, lithophile and chalcophile element abundances indicate hydrothermal overprint on the CT3 samples; this may also have influenced the redistribution of the meteoritic component(s). Last, we group the CT3 spherule layers, which occur in three intervals (A, B, and C), according to their petrographic and geochemical features, which indicate evidence for at least three distinct impact events before tectonic overprint that affected the original deposits.     

An alternative approach to overcome shortcomings with multiple testing of binary data in ecotoxicology

Binary data such as survival, hatching and mortality are assumed to be best described by a binomial distribution. This article provides a simple and straight forward approach for derivation of a no/lowest observed effect level (NOEL/LOEL) in a one-to-many control versus treatments setup. Practically, NOEL and LOEL values can be derived by means of different procedures, e.g. using Fisher’s exact test in coherence with adjusted p values. However, using adjusted p values heavily decreases statistical power. Alternatively, multiple t tests (e.g. Dunnett test procedure) together with arcsin-square-root transformations can be applied in order to account for variance heterogeneity of binomial data. Arcsin-square-root transformation, however, violates normal distribution because transformed data are constrained, while normal distribution provides data in the range \((-\infty ,\infty )\). Furthermore, results of statistical tests relying on an approximate normal distribution are approximate too. When testing for trends in probabilities of success (probs), the step down Cochran–Armitage trend test (CA) can be applied. The test statistic used is approximately normal. However, if probs approach 0 or 1, normal approximation of the null-distribution is suboptimal. Thus, critical values and p values lack statistical accuracy. We propose applying the closure principle (CP) and Fisher–Freeman–Halton test (FISH). The resulting CPFISH can solve the problems mentioned above. CP is used to overcome \(\alpha\)-inflation while FISH is applied to test for differences in probs between the control and any subset of treatment groups. Its applicability is presented by means of real data sets. Additionally, we performed a simulation study of 81 different setups (differing numbers of control replicates, numbers of treatments etc.), and compared the results of CPFISH to CA allowing us to point out the advantages and disadvantages of the CPFISH.     

Earthquakes in Switzerland and surrounding regions during 2012

This report of the Swiss Seismological Service summarizes the seismic activity in Switzerland and surrounding regions during 2012. During this period, 497 earthquakes and 88 quarry blasts were detected and located in the region under consideration. With a total of only 13 events with M_L ≥ 2.5, the seismic activity in the year 2012 was far below the average over the previous 37 years. Most noteworthy were the earthquake sequence of Filisur (GR) in January with two events of M_L 3.3 and 3.5, the M_L 4.2 and M_L 3.5 earthquakes at a depth of 32 km below Zug in February and the M_L 3.6 event near Vallorcine in October. The epicentral intensity of the M_L 4.2 event close to Zug was IV, with a maximum intensity of V reached in a few areas, probably due to site amplification effects.     

Book reviews

VANCOUVER'S CHINATOWN: racial discourse in Canada 1875–1980 by K. J. Anderson. 16 × 24 cm, 323 pages. McGill‐Queen's University Press, Montreal, 1991. (ISBN 07735 0844 9) $C34.95 (hard).

GEOGRAPHIC INFORMATION SYSTEMS: developments and applications edited by L. Worrall. 15 × 23 cm, 251 pages. Belhaven, London, 1990. (ISBN 1 85293 140 X) £45.00 (hard).

SAVANNA ECOLOGY AND MANAGEMENT: Australian perspectives and intercontinental comparisons edited by P. A. Werner. 22 × 27 cm, xii and 221 pages. Blackwell Scientific, Oxford, 1991. (ISBN 0 632 03199 9) $A89.00 (soft).

GLOBAL CHANGE AND CHALLENGE: geography for the 1990s edited by R. J. Bennett and R. Estall. 14 × 22 cm, xii and 264 pages. Routledge, London, 1991. (ISBN 0 415 00143 9) $A29.95 (soft).

PLAINS OF PROMISE RIVERS OF DESTINY: water management and the development of Queensland 1824–1990 by J. M. Powell. 17 × 24 cm, xvii and 395 pages. Boolarong Publications, Brisbane, 1991. (ISBN 0 7242 4470 0) $A40.00 (hard).

A SHARED HARVEST: The Australian Wheat Industry, 1939–1989 by G. Whitwell and D. Sydenham. 17 × 25 cm, xi and 324 pages. Macmillan, Melbourne, 1991. (ISBN 0 7329 0584 2) $A29.95 (hard).

TAMING THE GREAT SOUTH LAND: a history of the conquest of nature in Australia by W. J. Lines. 16 × 23cm, xx and 337 pages. Allen & Unwin, Sydney, 1991. (ISBN 1 86373 017 6) $A34.95 (hard).

PLAINS OF PROMISE RIVERS OF DESTINY: water management and the development of Queensland 1824–1990 by J. M. Powell. 17 × 24 cm, xvii and 395 pages. Boolarong Publications, Brisbane, 1991. (ISBN 0 7242 4470 0) $A40.00 (hard).

THE HUMANITIES AND THE AUSTRALIAN ENVIRONMENT: Papers from the Australian Academy of the Humanities Symposium edited by D. J. Mulvaney. 24 × 17 cm, xiii and 123 pages. Australian Academy of the Humanities, Canberra, 1991. (ISBN 0 909897 22 0) $A18.50 posted (soft).

GROWTH (Vol. 167, Sage Library of Social Research) by H. Teune. 141 pages. Sage Publications, Newbury Park, CA, 1988. (ISBN 0 8039 3183 2) US$46.00 (hard); (ISBN 0 8039 3190 5) US$22.95 (soft).

BEYOND GROWTH: elements of sustainable development by U.E. Simonis. 151 pages. Edition Sigma Bohn, Berlin, 1990. (ISBN 3 924859 56 6) DM24.80 (soft).

BEYOND BEEF: the rise and fall of the cattle culture by J. Rifkin. 16 × 24 cm, xi and 353 pages. Viking O'Neil, Melbourne, 1992. (ISBN 0 670 84844 1) $35.00 (hard).

A QUESTION OF PLACE: exploring the practice of human geography by R.J. Johnston. 15 × 23 cm, ix and 280 pages. Blackwell, Oxford, 1991. (ISBN 0 631 18207 1) $39.95 (soft).

GEOGRAPHY IN SOCIETY edited by R. Gerber. 21 × 29 cm, 92 pages. Royal Geographical Society of Queensland, Brisbane, [1992]. (ISBN 0 949286 02 8) $8.00 (soft).     

A new approach to overcome shortcomings with multiple testing of reproduction data in ecotoxicology

In ecotoxicology species reproduction tests and multiple testing of reproduction data are wide spread. While normal approximation of the data is a minor problem often the requirement of variance homogeneity is not fulfilled. Variance homogeneity is necessary to assure the proper application of statistical procedures like pairwise t tests, Dunnett t test, and Williams t test. A Poisson model can solve this issue preserving meaningful results and rendering statistical analysis more reliable. Moreover, sequential application of pairwise statistical “control vs. treatment” tests is a drawback concerning \(\alpha \)-inflation. The closure principle (CP) for hypothesis testing is used to generate a step-wise approach for detection of the No/Lowest Observed Effect Concentration using the computational approach test (CAT). The advantages and disadvantages of the combined CPCAT approach compared to the widely used t tests are pointed out and results of real data and fictitious data analysis are compared revealing the superiority of the Poisson model and CPCAT.