Created by the Monte Peron rock avalanche: Lago di Vedana (Dolomites, Italy) and its sediment record of landscape evolution after a mass wasting event

The timing of the Monte Peron Landslide is revised to 2890 cal. BP based on a radiocarbon-dated sediment stratigraphy of Lago di Vedana. This age fosters the importance of hydroclimatic triggers in the light of accelerating global warming with a predicted increase of precipitation enhancing the regional predisposition to large landslides. Moreover, a layer enriched in allochthonous organic and minerogenic detritus dating to the same wet period is interpreted as response to a younger and yet unidentified mass wasting event in the catchment of Lago di Vedana. Rock debris of the Monte Peron Landslide impounded the Cordevole River valley and created a landslide-dammed lake. Around AD 1150, eutrophication of this lacustrine ecosystem started with intensified human occupation – a process that ended 150 years later, when the river was diverted back into its original bed. Most likely, this occurred due to artificial opening of the river dam. In consequence, Lago di Vedana was isolated from an open and minerogenic to an endorheic and carbonaceous lacustrine system. After a monastery was established nearby in AD 1457, a second eutrophication process was initiated due to intensified land use linked with deforestation. Only in the eighteenth and nineteenth centuries, deposition of organic matter decreased coinciding with climatic (Little Ice Age) and cultural changes. Conversational measures are the likely reasons for a trend towards less eutrophic conditions since AD 1950.

Origin and evolution of the Yangtze River reconstructed from the largest molecular phylogeny of Cyprinidae

The Yangtze River is the longest river in Asia, but its evolutionary history has long been debated. So far no robust biological evidences can be found to crack this mystery. Here we reconstruct spatiotemporal and diversification dynamics of endemic East Asian cyprinids based on a largest molecular phylogeny of Cyprinidae, including 1420 species, and show that their ancestors laying adhesive eggs were distributed in southern East Asia before ~24 Ma, subsequently dispersed to the Yangtze River to spawn semi-buoyant eggs at ~19 Ma. This indicates that the Yangtze River diverted eastward around the Oligocene-Miocene boundary. Some of these cyprinids evolved again into fishes producing adhesive eggs at ~13 Ma, together with a peaked net diversification rate, indicating that the river formed a potamo-lacustrine ecosystem during the Mid-Miocene. Our reconstruction of the history of the Yangtze River has higher time resolution and much better continuity than those deriving from geological studies.

Volcanically driven lacustrine ecosystem changes during the Carnian Pluvial Episode (Late Triassic)

The Late Triassic Carnian Pluvial Episode (CPE) saw a dramatic increase in global humidity and temperature that has been linked to the large-scale volcanism of the Wrangellia large igneous province. The climatic changes coincide with a major biological turnover on land that included the ascent of the dinosaurs and the origin of modern conifers. However, linking the disparate cause and effects of the CPE has yet to be achieved because of the lack of a detailed terrestrial record of these events. Here, we present a multidisciplinary record of volcanism and environmental change from an expanded Carnian lake succession of the Jiyuan Basin, North China. New U–Pb zircon dating, high-resolution chemostratigraphy, and palynological and sedimentological data reveal that terrestrial conditions in the region were in remarkable lockstep with the large-scale volcanism. Using the sedimentary mercury record as a proxy for eruptions reveals four discrete episodes during the CPE interval (ca. 234.0 to 232.4 Ma). Each eruptive phase correlated with large, negative C isotope excursions and major climatic changes to more humid conditions (marked by increased importance of hygrophytic plants), lake expansion, and eutrophication. Our results show that large igneous province eruptions can occur in multiple, discrete pulses, rather than showing a simple acme-and-decline history, and demonstrate their powerful ability to alter the global C cycle, cause climate change, and drive macroevolution, at least in the Triassic.

Created by the Monte Peron rock avalanche: Lago di Vedana (Dolomites, Italy) and its sediment record of landscape evolution after a mass wasting event

The timing of the Monte Peron Landslide is revised to 2890 cal. BP based on a radiocarbon-dated sediment stratigraphy of Lago di Vedana. This age fosters the importance of hydroclimatic triggers in the light of accelerating global warming with a predicted increase of precipitation enhancing the regional predisposition to large landslides. Moreover, a layer enriched in allochthonous organic and minerogenic detritus dating to the same wet period is interpreted as response to a younger and yet unidentified mass wasting event in the catchment of Lago di Vedana. Rock debris of the Monte Peron Landslide impounded the Cordevole River valley and created a landslide-dammed lake. Around AD 1150, eutrophication of this lacustrine ecosystem started with intensified human occupation – a process that ended 150 years later, when the river was diverted back into its original bed. Most likely, this occurred due to artificial opening of the river dam. In consequence, Lago di Vedana was isolated from an open and minerogenic to an endorheic and carbonaceous lacustrine system. After a monastery was established nearby in AD 1457, a second eutrophication process was initiated due to intensified land use linked with deforestation. Only in the 18th and 19th century, deposition of organic matter decreased coinciding with climatic (Little Ice Age) and cultural changes. Conversational measures are the likely reasons for a trend towards less eutrophic conditions since AD 1950.

Helminth eggs from early cretaceous faeces

The exceptional fossil site of Las Hoyas (upper Barremian, Cuenca, Spain) yields abundant small to medium vertebrate coprolites, hindering the search for parasites. We studied the contents of 29 coprolites that were previously classified into distinct morphotypes. Several parasitic eggs were retrieved from two of these coprolites, confirming the second record of digenea trematode eggs and nematode (ascaridid) eggs from an Early Cretaceous locality. The cylindrical coprolite containing anisakid eggs was likely produced by a crocodylomorph as the parasite host, whereas the bump-headed lace coprolite indicates the role of a fish as an intermediary or definitive host of the trematodes and ascaridids. These trace and body fossils show that the Las Hoyas 126–129 Ma lacustrine ecosystem documents the early connection between basal Gonorynchiformes fish and digenetic trematodes.

Recovery of lacustrine ecosystems after the end-Permian mass extinction

The end-Permian mass extinction (EPME; ca. 252 Ma) led to profound changes in lacustrine ecosystems. However, whether or not post-extinction recovery of lacustrine ecosystems was delayed has remained uncertain, due to the apparent rarity of Early and Middle Triassic deep perennial lakes. Here we report on mid–Middle Triassic lacustrine organic-rich shales with abundant fossils and tuff interlayers in the Ordos Basin of China, dated to ca. 242 Ma (around the Anisian-Ladinian boundary of the Middle Triassic). The organic-rich sediments record the earliest known appearance, after the mass extinction, of a deep perennial lake that developed at least 5 m.y. earlier than the globally distributed lacustrine shales and mudstones dated as Late Triassic. The fossil assemblage in the organic-rich sediments is diverse and includes plants, notostracans, ostracods, insects, fishes, and fish coprolites, and thus documents a Mesozoic-type, trophically multileveled lacustrine ecosystem. The results reveal the earliest known complex lacustrine ecosystem after the EPME and suggest that Triassic lacustrine ecosystems took at most 10 m.y. to recover fully, which is consistent with the termination of the “coal gap” that signifies substantial restoration of peat-forming forests.

Iterative Subtractive Binning of Freshwater Chronoseries Metagenomes Identifies of over Four Hundred Novel Species and their Ecologic Preferences

Recent advances in sequencing technology and accompanying bioinformatic pipelines have allowed unprecedented access to the genomes of yet-uncultivated microorganisms from a wide array of natural and engineered environments. However, the catalogue of available genomes from uncultivated freshwater microbial populations remains limited, and most genome recovery attempts in freshwater ecosystems have only targeted few specific taxa. Here, we present a novel genome recovery pipeline, which incorporates iterative subtractive binning and apply it to a time series of metagenomic datasets from seven connected locations along the Chattahoochee River (Southeastern USA). Our set of Metagenome-Assembled Genomes (MAGs) represents over four hundred genomospecies yet to be named, which substantially increase the number of high-quality MAGs from freshwater lakes and represent about half of the total microbial community sampled. We propose names for two novel species that were represented by high-quality MAGs: “Candidatus Elulimicrobium humile” (“Ca. Elulimicrobiota” in the “Patescibacteria” group) and “Candidatus Aquidulcis frankliniae” (“Chloroflexi”). To evaluate the prevalence of these species in the chronoseries, we introduce novel approaches to estimate relative abundance and a habitat-preference score that control for uneven quality of the genomes and sample representation. Using these metrics, we demonstrate a high degree of habitat-specialization and endemicity for most genomospecies observed in the Chattahoochee lacustrine ecosystem, as well as wider species ecological ranges associated with smaller genomes and higher coding densities, indicating an overall advantage of smaller, more compact genomes for cosmopolitan distributions.