A theropod trackway providing evidence of a pathological foot from the exceptional locality of Las Hoyas (upper Barremian, Serranía de Cuenca, Spain).

We describe a trackway (LH-Mg-10-16) occurring in laminated carbonated limestones of the Las Hoyas locality, Serranía de Cuenca, Spain. It is unmistakably a large theropod dinosaur trackway encompassing two unusual aspects, namely, wide-steps, and a set of equally deformed left footprints (with a dislocated digit). The layer also preserves other vertebrate trails (fish Undichna) and different impressions in the sediment.

Archaeal overdominance close to life-limiting conditions in geothermally influenced hypersaline lakes at the Danakil Depression, Ethiopia.

The Dallol protovolcanic area on the Danakil Depression (Afar region, Ethiopia) exhibits unique hydrothermal manifestations in hypersaline context, yielding varied polyextreme physicochemical conditions. Previous studies identified a wide archaeal diversity in less extreme brines but failed to identify microorganisms thriving in either high-chaotropicity, low-water-activity brines or hyperacidic-hypersaline Na-Fe-rich brines. Recently, we accessed several small lakes under intense degassing activity adjacent to the Round Mountain, west to the Dallol dome [Western Canyon Lakes (WCL); WCL1-5].

Reductive evolution and unique predatory mode in the CPR bacterium Vampirococcus lugosii.

The Candidate Phyla Radiation (CPR) constitutes a large group of mostly uncultured bacterial lineages with small cell sizes and limited biosynthetic capabilities. They are thought to be symbionts of other organisms, but the nature of this symbiosis has been ascertained only for cultured Saccharibacteria, which are epibiotic parasites of other bacteria. Here, we study the biology and the genome of Vampirococcus lugosii, which becomes the first described species of Vampirococcus, a genus of epibiotic bacteria morphologically identified decades ago.

Environmental drivers of plankton protist communities along latitudinal and vertical gradients in the oldest and deepest freshwater lake.

Identifying which abiotic and biotic factors determine microbial community assembly is crucial to understand ecological processes and predict how communities will respond to environmental change. While global surveys aim at addressing this question in the world's oceans, equivalent studies in large freshwater systems are virtually lacking. Being the oldest, deepest and most voluminous freshwater lake on Earth, Lake Baikal offers a unique opportunity to test the effect of horizontal versus vertical gradients in community structure.

Hyperdiverse archaea near life limits at the polyextreme geothermal Dallol area.

Microbial life has adapted to various individual extreme conditions; yet, organisms simultaneously adapted to very low pH, high salt and high temperature are unknown. We combined environmental 16S/18S ribosomal RNA gene metabarcoding, cultural approaches, fluorescence-activated cell sorting, scanning electron microscopy and chemical analyses to study samples along such unique polyextreme gradients in the Dallol-Danakil area in Ethiopia. We identified two physicochemical barriers to life in the presence of surface liquid water defined by (1) high chaotropicity-low water activity in Mg/Ca-dominated brines and (2) hyperacidity-salt combinations (pH ~0/NaCl-dominated salt saturation).

The Effect Of microbial Mats In The Decay Of Anurans With Implications For Understanding Taphonomic Processes In The Fossil Record.

The pattern and sequence of the decomposition of the Pipidae African dwarf frog (Hymenochirus boettgeri) is tracked in an experiment with microbial mats in order to explore soft tissue preservation over three years. Frog decay in microbial mats is preceded by rapid entombment (25-30 days) and mediated by the formation of a sarcophagus, which is built by a complex microbial community. The frog carcasses maintained a variety of soft tissues for years.

Comparative metagenomics unveils functions and genome features of microbialite-associated communities along a depth gradient.

Modern microbialites are often used as analogs of Precambrian stromatolites; therefore, studying the metabolic interplay within their associated microbial communities can help formulating hypotheses on their formation and long-term preservation within the fossil record. We performed a comparative metagenomic analysis of microbialite samples collected at two sites and along a depth gradient in Lake Alchichica (Mexico). The community structure inferred from single-copy gene family identification and long-contig (>10 kb) assignation, consistently with previous rRNA gene surveys, showed a wide prokaryotic diversity dominated by Alphaproteobacteria, Gammaproteobacteria, Cyanobacteria, and Bacteroidetes, while eukaryotes were largely dominated by green algae or diatoms.

Involvement of microbial mats in early fossilization by decay delay and formation of impressions and replicas of vertebrates and invertebrates.

Microbial mats have been hypothesized to improve the persistence and the preservation of organic remains during fossilization processes. We test this hypothesis with long-term experiments (up to 5.5 years) using invertebrate and vertebrate corpses.

Metagenome-based diversity analyses suggest a significant contribution of non-cyanobacterial lineages to carbonate precipitation in modern microbialites.

Cyanobacteria are thought to play a key role in carbonate formation due to their metabolic activity, but other organisms carrying out oxygenic photosynthesis (photosynthetic eukaryotes) or other metabolisms (e.g., anoxygenic photosynthesis, sulfate reduction), may also contribute to carbonate formation.

Spreading topsoil encourages ecological restoration on embankments: soil fertility, microbial activity and vegetation cover.

The construction of linear transport infrastructure has severe effects on ecosystem functions and properties, and the restoration of the associated roadslopes contributes to reduce its impact. This restoration is usually approached from the perspective of plant cover regeneration, ignoring plant-soil interactions and the consequences for plant growth. The addition of a 30 cm layer of topsoil is a common practice in roadslope restoration projects to increase vegetation recovery.

Regulation and spatiotemporal patterns of extracellular enzyme activities in a coastal, sandy aquifer system (Doñana, SW Spain).

A seasonal study of extracellular enzyme activities (EEA) was conducted in the coastal, sandy aquifer system located in the greater fluvial-littoral ecosystem of Doñana (SW, Spain). Glucosidase, leucine aminopeptidase, alkaline phosphatase, and phenol oxidase activities were determined over a 2-year period in 30 piezometers spread in an area of approximately 100 km(2). Taking into account all enzymes, piezometers, and seasons, EEA ranged over several orders of magnitude, from 1.

Spatiotemporal distribution of microbial communities in a coastal, sandy aquifer system (Doñana, SW Spain).

The aquifer system of Doñana (SW Spain) represents the most important freshwater source in the Doñana Natural Area. Its spatiotemporal dynamics favours the hydrological connection between surface and subsurface ecosystems, and promotes matter fluxes among the different terrestrial and aquatic systems present here. This aquifer has been intensively studied from a hydrogeological point of view but little is known from an ecological perspective.

Ecological study of the fungal populations of the acidic Tinto River in southwestern Spain.

The characterization of the microbial ecology of the Tinto River, an extreme habitat with an extremely low pH and a high concentration of heavy metals, revealed an unexpected level of microbial richness. A variety of microbial eukaryotes was isolated, among them several fungal strains that were identified and their physiological characteristics studied. Ninety strains of yeast were isolated from the Tinto River.

Macrofilamentous microbial communities in the metal-rich and acidic River Tinto, Spain.

A novel type of macroscopic microbial community consisting of large dendritic filaments (up to 1.5 m) in a pH 2.0 dam of the River Tinto (South-western Spain) is described.

Phytoplankton diversity and cyanobacterial dominance in a hypereutrophic shallow lake with biologically produced alkaline pH.

In this work, we have characterized the diversity of phytoplanktonic species in a highly alkaline and hypereutrophic shallow lake, Santa Olalla (southwestern Spain), the evolution of their relative abundances, and that of several physicochemical parameters over 2 years. In the absence of an external input of alkaline water, Santa Olalla's stable high pH (average pH 9.52, with several maxima >10.

Microbial Community Composition and Ecology of an Acidic Aquatic Environment: The Tinto River, Spain.

We studied the correlation between physicochemical and biological characteristics of an acidic river, the Tinto River, in Southwestern Spain. The Tinto River is an extreme environment characterized by its low pH (mean of 2.2) and high concentrations of heavy metals (Fe 2.

A Comparative Ecological Study of Two Acidic Rivers in Southwestern Spain.

> Abstract We have analyzed select physicochemical and biological characteristics of two acidic rivers, the Tinto and the Odiel, located in the Pyritic Belt of Southwestern Spain. Despite a common geography and geochemistry, they exhibit important differences. Most of the measured physicochemical parameters, especially pH and those related to conductivity (heavy metal concentrations), showed more extreme values in the Tinto than in the Odiel.