14 research outputs found
Impact of an 0.2 km 3 Rock Avalanche on Lake Eibsee (Bavarian Alps, Germany) – Part II: Catchment Response to Consecutive Debris Avalanche and Debris Flow
The ~0.2 km3 Eibsee rock avalanche impacted Paleolake Eibsee and completely displaced its waters. This study anal- yses the lake impact and the consequences, and the catchment response to the landslide. A quasi‐3D seismic reflection survey, four sediment cores from modern Lake Eibsee, reaching far down into the rock avalanche mass, nine radiocarbon ages, and geomorphic analysis allow us to distinguish the main rock avalanche event from a secondary debris avalanche and debris flow. The highly flu- idized debris avalanche formed a megaturbidite and multiple swashes that are recorded in the lake sediments. The new calibrated age for the Eibsee rock avalanche of ~4080–3970 cal yr BP indicates a coincidence with rockslides in the Fernpass cluster and sub- aquatic landslides in Lake Piburg and Lake Plansee, and raises the possibility that a large regional earthquake triggered these events. We document a complex history of erosion and sedimentation in Lake Eibsee, and demonstrate how the catchment response and rebirth of the lake are revealed through the complementary application of geophysics, sedimentology, radiocarbon dating, and geo- morphology
A conserved regulatory program initiates lateral plate mesoderm emergence across chordates
Cardiovascular lineages develop together with kidney, smooth muscle, and limb connective tissue progenitors from the lateral plate mesoderm (LPM). How the LPM initially emerges and how its downstream fates are molecularly interconnected remain unknown. Here, we isolate a pan-LPM enhancer in the zebrafish-specific draculin (drl) gene that provides specific LPM reporter activity from early gastrulation. In toto live imaging and lineage tracing of drl-based reporters captures the dynamic LPM emergence as lineage-restricted mesendoderm field. The drl pan-LPM enhancer responds to the transcription factors EomesoderminA, FoxH1, and MixL1 that combined with Smad activity drive LPM emergence. We uncover specific activity of zebrafish-derived drl reporters in LPM-corresponding territories of several chordates including chicken, axolotl, lamprey, Ciona, and amphioxus, revealing a universal upstream LPM program. Altogether, our work provides a mechanistic framework for LPM emergence as defined progenitor field, possibly representing an ancient mesodermal cell state that predates the primordial vertebrate embryo
Impact of an 0.2 km3 Rock Avalanche on Lake Eibsee (Bavarian Alps, Germany) – Part I: Reconstruction of the paleolake and Effects of the Impact
Rock avalanches destroy and reshape landscapes in only a few minutes and are among the most hazardous processes on Earth. The surface morphology of rock avalanche deposits and the interaction with the underlying material are crucial for runout properties and reach. Water within the travel path is displaced, producing large impact waves and reducing friction, leading to long runouts. We hypothesize that the 0.2 km3 Holocene Eibsee rock avalanche from Mount Zugspitze in the Bavarian Alps overran and destroyed Paleolake Eibsee and left a unique sedimentological legacy of processes active during the landslide. We captured 9.5 km of electrical resistivity tomography (ERT) profiles across the rock avalanche deposits, with up to 120 m penetration depth and more than 34 000 datum points. The ERT profiles reveal up to ~50 m thick landslide debris, locally covering up to ~30 m of rock debris with entrained fine‐grained sediments on top of isolated remnants of decametre‐wide paleolake sediments. The ERT profiles allow us to infer processes involved in the interaction of the rock avalanche with bedrock, lake sediments, and morainal sediments, including shearing, bulging, and bulldozing. Complementary data from drilling, a gravel pit exposure, laboratory tests, and geomorphic features were used for ERT calibration. Sediments overrun by the rock avalanche show water‐escape structures. Based on all of these datasets, we reconstructed both position and size of the paleolake prior to the catastrophic event. Our reconstruction of the event contributes to process an understanding of the rock avalanche and future modelling and hazard assessment. Here we show how integrated geomorphic, geophysical, and sedimentological approaches can provide detailed insights into the impact of a rock avalanche on a lake. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons LtdThe Eibsee rock avalanche detached from Mount Zugspitze and impacted and destroyed Paleolake Eibsee. Paleolake Eibsee was larger than modern Lake Eibsee; the rock avalanche deposit covers the northern half of the paleolake. The complementary application of geomorphology, electrical resistivity tomography (ERT) and sedimentology allows for ERT calibration at seven different sites, where materials (rock avalanche, bedrock, lake clay, mixed sediments) and effects of the impact (bulldozing, bulging, overriding of secondary lobes, splashing of boulders) can be distinguished.Studienstiftung des Deutschen Volkes e.V. (German National Academic Foundation):
http://dx.doi.org/10.13039/50110000435
Impact of an 0.2 km3 Rock Avalanche on Lake Eibsee (Bavarian Alps, Germany) – Part II: Catchment Response to Consecutive Debris Avalanche and Debris Flow
The ~0.2 km3 Eibsee rock avalanche impacted Paleolake Eibsee and completely displaced its waters. This study analyses the lake impact and the consequences, and the catchment response to the landslide. A quasi‐3D seismic reflection survey, four sediment cores from modern Lake Eibsee, reaching far down into the rock avalanche mass, nine radiocarbon ages, and geomorphic analysis allow us to distinguish the main rock avalanche event from a secondary debris avalanche and debris flow. The highly fluidized debris avalanche formed a megaturbidite and multiple swashes that are recorded in the lake sediments. The new calibrated age for the Eibsee rock avalanche of ~4080–3970 cal yr BP indicates a coincidence with rockslides in the Fernpass cluster and subaquatic landslides in Lake Piburg and Lake Plansee, and raises the possibility that a large regional earthquake triggered these events. We document a complex history of erosion and sedimentation in Lake Eibsee, and demonstrate how the catchment response and rebirth of the lake are revealed through the complementary application of geophysics, sedimentology, radiocarbon dating, and geomorphology. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons LtdSedimentological, geophysical and geomorphological investigation in and around Lake Eibsee allows to decipher three rock‐slope failures from Mount Zugspitze: (i) the Eibsee rock avalanche ~4000 cal yr BP; (ii) a debris avalanche in the aftermath; and (iii) a large debris flow ~3740 cal yr BP. The Eibsee rock avalanche was re‐dated to a refined age of 4089–3876 cal yr BP. The coincidence with major events in the Fernpass rockslide cluster increases the likelihood of a prehistoric earthquake trigger.Studienstiftung des Deutschen Volkes e.V. (German National Academic Foundation):
http://dx.doi.org/10.13039/501100004350British Society for Geomorphology
http://dx.doi.org/10.13039/10001016
Support for Association of Schizophrenia with Genetic Variation in the 6p22.3 Gene, Dysbindin, in Sib-Pair Families with Linkage and in an Additional Sample of Triad Families
Genetic variants in a gene on 6p22.3, dysbindin, have been shown recently to be associated with schizophrenia (Straub et al. 2002a). There is no doubt that replication in other independent samples would enhance the significance of this finding considerably. Since the gene is located in the center of the linkage peak on chromosome 6p that we reported earlier, we decided to test six of the most positive DNA polymorphisms in a sib-pair sample and in an independently ascertained sample of triads comprising 203 families, including the families for which we detected linkage on chromosome 6p. Evidence for association was observed in the two samples separately as well as in the combined sample (P=.00068 for SNP rs760761). Multilocus haplotype analysis increased the significance further to .00002 for a two-locus haplotype and to .00001 for a three-locus haplotype. Estimation of frequencies for six-locus haplotypes revealed one common haplotype with a frequency of 73.4% in transmitted, and only 57.6% in nontransmitted, parental haplotypes. All other six-locus haplotypes occurring at a frequency of >1% were less often transmitted than nontransmitted. Our results represent a first successful replication of linkage disequilibrium in psychiatric genetics detected in a region with previous evidence of linkage and will encourage the search for causes of schizophrenia by the genetic approach
Sequencing the GRHL3 Coding Region Reveals Rare Truncating Mutations and a Common Susceptibility Variant for Nonsyndromic Cleft Palate
Nonsyndromic cleft lip with/without cleft palate (nsCL/P) and nonsyndromic cleft palate only (nsCPO) are the most frequent subphenotypes of orofacial clefts. A common syndromic form of orofacial clefting is Van der Woude syndrome (VWS) where individuals have CL/P or CPO, often but not always associated with lower lip pits. Recently, similar to 5% of VWS-affected individuals were identified with mutations in the grainy head-like 3 gene (GRHL3). To investigate GRHL3 in nonsyndromic clefting, we sequenced its coding region in 576 Europeans with nsCL/P and 96 with nsCPO. Most strikingly, nsCPO-affected individuals had a higher minor allele frequency for rs41268753 (0.099) than control subjects (0.049; p = 1.24 x 10(-2)). This association was replicated in nsCPO/control cohorts from Latvia, Yemen, and the UK (p(combined) = 2.63 x 10(-5); ORallelic = 2.46 [95% CI 1.6-3.7]) and reached genome-wide significance in combination with imputed data from a GWAS in nsCPO triads (p = 2.73 x 10(-9)). Notably, rs41268753 is not associated with nsCL/P (p = 0.45). rs41268753 encodes the highly conserved p.Thr454Met (c.1361C>T) (GERP = 5.3), which prediction programs denote as deleterious, has a CADD score of 29.6, and increases protein binding capacity in silico. Sequencing also revealed four novel truncating GRHL3 mutations including two that were de novo in four families, where all nine individuals harboring mutations had nsCPO. This is important for genetic counseling: given that VWS is rare compared to nsCPO, our data suggest that dominant GRHL3 mutations are more likely to cause nonsyndromic than syndromic CPO. Thus, with rare dominant mutations and a common risk variant in the coding region, we have identified an important contribution for GRHL3 in nsCPO