Experimental reconstruction of temperature - altitude in the past remain often elusive. With the development of a combined vacuum crushing and sieving system (CVCS), it is now possible to determine paleotemperatures from the noble gases dissolved in minute amounts of water from inclusions in speleothems that have grown under a broad range of climatic conditions. Here we present noble gas temperature (NGT) estimates during the last deglaciation, which are based on two stalagmites from Milandre Cave (stalagmite M6) and Grotte aux Fées de Vallorbe (stalagmite GEF1), Jura Mountains, Switzerland. The caves are located at different geographical altitudes (Milandre Cave: 373 m a.s.l. and Grotte aux Fées de Vallorbe: 895 m a.s.l.) and thus allow for a reconstruction of the respective temperature - altitude gradients within Switzerland during the last deglaciation. Our reconstruction shows that the past temperature - altitude gradients are within 1σ error in agreement with the modern temperature - altitude gradient, suggesting that the local temperature - altitude gradient was rather stable over time.<br /> In addition to the noble gas analysis, we complemented our study with deuterium (<em>δ</em>D_FI) and oxygen isotope (<em>δ</em>¹⁸O_FI) measurements of fluid inclusion water. In combination with NGTs, this allows us to reconstruct the past <em>δ</em>¹⁸O_FI - <em>δ</em>D_FI / temperature relation. These reconstructions show that the temporal temperature sensitivity of <em>δ</em>¹⁸O_FI and <em>δ</em>D_FI (Δ(<em>δ</em>¹⁸O_FI) / Δ(T) and Δ(<em>δ</em>D_FI) / Δ(T)) seems to be stable over time and therefore support the use of water isotopes for temperature reconstructions in Switzerland.

Temperature is a key factor that influences chemical biotransformation potential and rates, on which exposure and fate models rely to predict the environmental (micro)pollutant fate. Arrhenius-based models are currently implemented in environmental exposure assessment to adapt biotransformation rates to actual temperatures, assuming validity in the 0-30 °C range. However, evidence on how temperature shifts affect the physicochemical and microbial features in biological systems is scarce, questioning the validity of the existing modeling approaches. In this work, laboratory-scale batch assays were designed to investigate how a mixed microbial community responds to short-term temperature shifts, and how this impacts its ability to biotransform a range of structurally diverse micropollutants. Our results revealed three distinct kinetic responses at temperatures above 20 °C, mostly deviating from the classic Arrhenius-type behavior. Micropollutants with similar temperature responses appeared to undergo mostly similar initial biotransformation reactions, with substitution-type reactions maintaining Arrhenius-type behavior up to higher temperatures than oxidation-type reactions. Above 20 °C, the microbial community also showed marked shifts in both composition and activity, which mostly correlated with the observed deviations from Arrhenius-type behavior, with compositional changes becoming a more relevant factor in biotransformations catalyzed by more specific enzymes (e.g., oxidation reactions). Our findings underline the need to re-examine and further develop current environmental fate models by integrating biological aspects, to improve accuracy in predicting the environmental fate of micropollutants.

The last decade brought a spectacular development of so-called environmental (e)DNA studies. In general, “environmental DNA” is defined as DNA isolated from environmental samples, in contrast to genomic DNA that is extracted directly from specimens. However, the variety of different sources of eDNA and the range of taxonomic groups that are targeted by eDNA studies is large, which has led to some discussion about the breadth of the eDNA concept. In particular, there is a recent trend to restrict the use of the term “eDNA” to the DNA of macro-organisms, which are not physically present in environmental samples. In this paper, we argue that such a distinction may not be ideal, because the eDNA signal can come from organisms across the whole tree of life. Consequently, we advocate that the term “eDNA” should be used in its generic sense, as originally defined, encompassing the DNA of all organisms present in environmental samples, including microbial, meiofaunal and macrobial taxa. We first suggest specifying the environmental origin of the DNA sample, such as water eDNA, sediment eDNA or soil eDNA. A second specification would then define the taxonomic group targeted through polymerase chain reaction amplification, such as fish eDNA, invertebrate eDNA and bacterial eDNA. This terminology does also not require assumptions about the specific state of the DNA sampled (intracellular or extracellular). We hope that such terminology will help better define the scope of eDNA studies, especially for environmental managers, who use them as reference in routine biomonitoring and bioassessment.

In der vorliegenden Arbeit wird eine neue Blaualge <em>Plectonema capitata</em> beschrieben und ein Beitrag geliefert zur Kenntnis der Fadenmorphologie und der Ausbildung der Scheide bei den Cyanophyceen.