Downwearing rates on shore platforms of different calcareous lithotypes

Vertical lowering (downwearing) of shore platform surfaces is a very important mechanism in their morphological evolution albeit much remains incompletely understood. The efficacy of mechanical and chemical weathering acting on a given substrate, together with erosional processes, influences downwearing rates. In order to determine the relationship between lithotypes and downwearing rates, data collected from a Transverse Micro-erosion Meter were obtained for shore platforms of three different calcareous lithotypes (biocalcarenite, calcarenite and carbonated siltstone) along the central Algarve coast (Southern Portugal). Downwearing rates ranged between 0.096 mm year−1 and 1.676 mm year−1 in biocalcarenite and weakly cemented calcarenite, respectively. In addition, physical properties of the rocks comprising the platforms were measured, including uniaxial compressive strength (as determined by the Point Load Test), porosity, and calcium carbonate content. The results show that downwearing depends primarily on the intrinsic properties of the substrate. Porosity, in particular, acts in two ways: (i) it tends to weaken the substrate; and, (ii) it controls the downward extent of the water percolation and therefore the depth of the weathering mantle subject to erosion by waves and currents.Portuguese Foundation for Science and Technology (FCT) through Research Projects PTDC/CTEGEX/70448/2006 (BISHOP) and PTDC/CTE-GIX/111230/2009 (EROS)

GENOMICS SYMPOSIUM: Using genomic approaches to uncover sources of variation in age at puberty and reproductive longevity in sows

Genetic variants associated with traits such as age at puberty and litter size could provide insight into the underlying genetic sources of variation impacting sow reproductive longevity and productivity. Genomewide characterization and gene expression profiling were used using gilts from the University of Nebraska–Lincoln swine resource population (n = 1,644) to identify genetic variants associated with age at puberty and litter size traits. From all reproductive traits studied, the largest fraction of phenotypic variation explained by the Porcine SNP60 BeadArray was for age at puberty (27.3%). In an evaluation data set, the predictive ability of all SNP from highranked 1-Mb windows (1 to 50%), based on genetic variance explained in training, was greater (12.3 to 36.8%) compared with the most informative SNP from these windows (6.5 to 23.7%). In the integrated data set (n = 1,644), the top 1% of the 1-Mb windows explained 6.7% of the genetic variation of age at puberty. One of the high-ranked windows detected (SSC2, 12–12.9 Mb) showed pleiotropic features, affecting both age at puberty and litter size traits. The RNA sequencing of the hypothalami arcuate nucleus uncovered 17 differentially expressed genes (adjusted P \u3c 0.05) between gilts that became pubertal early (180 d of age). Twelve of the differentially expressed genes are upregulated in the late pubertal gilts. One of these genes is involved in energy homeostasis (FFAR2), a function in which the arcuate nucleus plays an important contribution, linking nutrition with reproductive development. Energy restriction during the gilt development period delayed age at puberty by 7 d but increased the probability of a sow to produce up to 3 parities (P \u3c 0.05). Identification of pleotropic functional polymorphisms may improve accuracy of genomic prediction while facilitating a reduction in sow replacement rates and addressing welfare concerns

The roles of age at puberty and energy restriction |in sow reproductive longevity: a genomic perspective

Approximately 50% of sows are culled annually with more than one-third due to poor fertility. Our research demonstrated that age at puberty is an early pre-breeding indicator of reproductive longevity. Age at puberty can be measured early in life, has a moderate heritability, and is negatively correlated with lifetime number of parities. Detection of age at puberty is tedious and time consuming and is therefore not collected by the industry, which limits genetic progress. Genomic prediction is a viable approach to preselect gilts that will express puberty early and have superior reproductive longevity. The hypothesis that genetic variants explaining differences in age at puberty also explain differences in sow reproductive longevity was tested. Phenotypes, genotypes, and tissues from the UNL resource population (n \u3e 1700) were used in genome-wide association analyses, genome, and RNA sequencing to uncover functional polymorphisms that could explain variation in puberty and reproductive longevity. A BeadArray including 56,424 SNP explained 25.2% of the phenotypic variation in age at puberty in a training set (n = 820). Evaluation of major windows and SNPs of subsequent batches of similar genetics (n = 412) showed that if all SNPs located in the major 1-Mb windows were tested, they explained a substantial amount of phenotypic variation (12.3 to 36.8%). Due to differences in linkage disequilibrium status, the most informative SNP from these windows explained a lower proportion of the variation (6.5 to 23.7%). To improve genomic predictive ability, the limited capability of BeadArray was enhanced by potential functional variants uncovered by genome sequencing of selected sires (n = 20; \u3e20X). There were 11.2 mil. SNPs and 2.9 mil. indels discovered across sires and reference genomes. The role of gene expression differences in explaining phenotypic variation in age at puberty was investigated by RNA sequencing of the hypothalamic arcuate nucleus (ARC) in gilts (n = 37) with different pubertal statuses. Seventy genes, including genes involved in reproductive processes, were differentially expressed between gilts with early and late puberty status (Padj \u3c 0.1). Dietary restriction of energy 3 mo before breeding delayed puberty by 7 d but improved the potential of a sow producing up to three parities (P \u3c 0.05). Energy restriction was associated with differential expression in 42 genes in the ARC, including genes involved in energy metabolism. This integrated genomic information will be evaluated in commercial populations to improve the reproductive potential of sows through genomic selection. This project is supported by AFRI Competitive grant no. 2013-68004-20370 from the USDA-NIFA. USDA is an equal opportunity provider and employer

Late Quaternary sea-level change and early human societies in the central and eastern Mediterranean Basin : an interdisciplinary review

This article reviews key data and debates focused on relative sea-level changes since the Last Interglacial (approximately the last 132,000 years) in the Mediterranean Basin, and their implications for past human populations. Geological and geomorphological landscape studies are critical to archaeology. Coastal regions provide a wide range of resources to the populations that inhabit them. Coastal landscapes are increasingly the focus of scholarly discussions from the earliest exploitation of littoral resources and early hominin cognition, to the inundation of the earliest permanently settled fishing villages and eventually, formative centres of urbanisation. In the Mediterranean, these would become hubs of maritime transportation that gave rise to the roots of modern seaborne trade. As such, this article represents an original review of both the geo-scientific and archaeological data that specifically relate to sea-level changes and resulting impacts on both physical and cultural landscapes from the Palaeolithic until the emergence of the Classical periods. Our review highlights that the interdisciplinary links between coastal archaeology, geomorphology and sea-level changes are important to explain environmental impacts on coastal human societies and human migration. We review geological indicators of sea level and outline how archaeological features are commonly used as proxies for measuring past sea levels, both gradual changes and catastrophic events. We argue that coastal archaeologists should, as a part of their analyses, incorporate important sea-level concepts, such as indicative meaning. The interpretation of the indicative meaning of Roman fishtanks, for example, plays a critical role in reconstructions of late Holocene Mediterranean sea levels. We identify avenues for future work, which include the consideration of glacial isostatic adjustment (GIA) in addition to coastal tectonics to explain vertical movements of coastlines, more research on Palaeolithic island colonisation, broadening of Palaeolithic studies to include materials from the entire coastal landscape and not just coastal resources, a focus on rescue of archaeological sites under threat by coastal change, and expansion of underwater archaeological explorations in combination with submarine geomorphology. This article presents a collaborative synthesis of data, some of which have been collected and analysed by the authors, as the MEDFLOOD (MEDiterranean sea-level change and projection for future FLOODing) community, and highlights key sites, data, concepts and ongoing debates

Freeze-thaw and shore platform development in Gaspé, Québec

The role of freeze-thaw action in coastal environments, with particular reference to the formation of sub-horizontal shore platforms in Gaspé, Québec, was investigated experimentally. Rock cores and crushed rock samples were subjected to: two freeze-thaw cycles of twelve and twenty-four hour durations; fresh water and three artificial sea water solutions of about half, one and a half, and 'normal' salinity; and two drainage conditions representing rock pools and vertical well drained surfaces. These variables were selected to simulate some of the local environments which exist between the cliff top and low tide level in coastal Gaspé. Shales were the most susceptible to frost breakdown, followed in turn by argillites, calcisiltites and dolomitic silty argillites, and graywackes. Greatest disintegration tended to be associated with sea water solutions of about half-normal salinity. The data suggest that breakdown is greatest in the lower portions of the cliff. Freeze-thaw may produce the moat-like pools commonly found at the back of shore platforms. Although the process undoubtedly facilitates wave erosion of the platform and cliff, however, there is no evidence to suggest that it causes shore platforms to assume subhorizontal gradients.Le rôle de la gélifraction en milieu littoral, en particulier dans la formation des plates-formes subhorizontales en Gaspésie, a été étudié d’une façon expérimentale. Des carottes et des fragments de roc ont été soumis à des cycles gel-dégel de 12 et de 24 heures, les uns dans de l’eau ordinaire et les autres dans de l’eau de mer à salinité normale, à demi-salinité et à salinité et demie, dans des conditions d’humidité correspondant à celles des cuvettes rocheuses et des escarpements verticaux. Les conditions furent déterminées en regard des milieux naturels locaux prévalant dans la zone comprise entre le haut de la falaise et le niveau des basses mers, sur la côte nord de la Gaspésie. Les schistes se sont révélés les plus sensibles à la gélifraction; viennent ensuite dans l’ordre de plus grande sensibilité, les argilites, les calcshistes, les argilites dolomitiques et les grauwackes. La gélifraction maximale s’est produite dans une solution correspondant à la demi-salinité de l’eau de mer. Les résultats indiquent que la gélifraction est plus importante dans la partie inférieure de la falaise. Elle pourrait être à l’origine des cuvettes superficielles entaillant les plates-formes littorales. Bien que la gélifraction soit un processus favorisant l’érosion par les vagues des plates-formes et des falaises, rien ne permet d’affirmer qu’elle soit à l’origine des plates-formes littorales subhorizontales en Gaspé.Die Rolle der Gelifraktion in Kustengegenden, mit besonderem Hinweis auf die Entstehung von subhorizontalen Küstenplattformen in Gaspé, Québec, wurde im Experiment untersucht. Bohrungskerne und zermahlene Gesteinsproben wurden folgenden Kräften aus-gesetzt: zwei Gefrierund Auftauzyklen von zwölf und vierundzwanzig Stunden Dauer, Frischwasser, und drei künstliche Salzwasserlösungen von ungefähr halber, anderthalber und "normaler" Salinität, und zwei Entwässerungs Verhältnissen, die einem Felskessel und senkrechten, gut drainierten Oberflächen entsprechen. Diese Varianten wurden gewählt, weil sie die örtlichen Umweltverhältnisse nachahmen, die man zwischen den Felsspitzen und der Ebbelinie an der Gaspé Küste finded. Die Tonschiefer waren am meisten von der Frostsprengung beeinflusst. Der Ordnung nach folgten, Argilite, Kalcisiltite, und dolomitische siltische Argi Mite und grau wacken. Die grösste Zersetzung wurde bei Seewassersolutionen von halb normaler Stärke beobachtet. Die Daten zeigen, dass der Verfall in der unteren Hälfte des Kliffs am grössten ist. Die Frosstsprengung könnte auch die flachen Becken hervorrufen, die man oft hinter der Küstenplattform finded. Wärend Frostsprengung ohne Zweifel die Wellenerosion der Küstenplattform und des Kliffs erleichtert, besteht jedoch kein Beweis, dass sie der Küstenplattform einen subhorizontalen Winkel gibt

Evolution and inheritance of a rock coast: Western Galicia, Northwestern Spain

[EN] There is increasing evidence that shore platforms and other elements of rock coasts may be inherited, at least in part, from interglacial stages when sea level was similar to today's. Most of this evidence, which includes ancient beaches and datable terrestrial deposits, has been obtained from areas of resistant, slowly eroding rock, where the platforms often appear to be much too wide to have developed since the sea reached its present level. It is much more difficult to demonstrate that inheritance has occurred in areas of weaker rock, which generally lack any datable material. The coast of western Galicia in northwestern Spain has shore platforms in igneous and metamorphic rocks that were deeply weathered during the Tertiary. These platforms are closely associated with ancient beaches from the last interglacial stage, and associated periglacial and fluvio-nival deposits that covered and fossilized most of the Eemian platforms and cliffs during the late middle and late Weichselian glacial stage. The sedimentary processes and the thickness and facies of the sediments were determined by the height, aspect and gradient of the coastal mountains, and their distance from the coast. Radiocarbon dating, sedimentary analysis and platform morphology indicate that the shore platforms of Galicia have been inherited from at least the last interglacial stage. They were fossilized in places beneath thick Weichselian deposits and then exhumed during the Holocene transgression. The abundant evidence for inheritance in Galicia has important implications for other coasts in fairly weak rocks where such evidence is generally lacking.[ES] Hay una creciente evidencia de que las plataformas de tierra y otros elementos de las costas rocosas pueden ser hereditarios, por lo menos en parte, de las fases interglaciares, cuando el nivel del mar fue similar a la de hoy. La mayor parte de esta evidencia, que incluye las playas de antiguos depósitos terrestres y datables, se ha obtenido de las zonas de roca resistente, erosionando lentamente, en donde las plataformas a menudo parecen ser demasiado amplias para haberse desarrollado desde que desde el mar alcanzó su nivel actual. Es mucho más difícil demostrar que la herencia se ha producido en las zonas más débiles de la roca, que en general carecen de cualquier material fechable. La costa occidental de Galicia en el noroeste de España, tiene plataformas marinas en las rocas ígneas y metamórficas que fueron muy erosionadas durante el Terciario. Estas plataformas están estrechamente relacionados con las playas antiguas de la última etapa interglacial, y se asocia depósitos periglaciares y fluvio-nivales que cubrieron y fosilizaron la mayoría de las plataformas Eemiense y acantilados durante la mitad y finales de finales de etapa glacial Weichseliense. Los procesos sedimentarios y el espesor y facies de los sedimentos se determinaron por la altura, la orientación y pendiente de las montañas de la costa, y su distancia de la costa. La datación por radiocarbono, análisis de sedimentos y la morfología de la plataforma indican que las plataformas marinas de Galicia se han heredado de por lo menos en la última etapa interglacial. Estas fueron fosilizadas en lugares por debajo de gruesos depósitos Weichseliense y luego exhumadas durante la transgresión del Holoceno. La abundante evidencia de la herencia en Galicia tiene importantes implicaciones para otras costas de rocas bastante débiles, dónde la carencia de tales evidencias es general.Peer reviewe