Open Access Publications of the European Geosciences Union (EGU) with examples from Climate of the Past Facts, Innovative Approaches, Dissemination

This is the presentation of the EGU open access journals and how they are working using my experience of Co-editor in chief of Climate of the Past. I gave this lecture in Montpellier, France, 10 January 201

The 30th anniversary of the CEEC : from ongoing evaluation to current challenges

Entrevue : propos recueillis par Anne-Marie Paquette, rédactrice en chef.Disponible en français dans EDUQ.info sous le titre "Les 30 ans de la CEEC : entre évaluation continue et défis actuels""The Commission d’évaluation de l’enseignement collégial (CEEC) is celebrating its 30th anniversary this year. For some, it has embodied a culture of ongoing evaluation since its creation in 1993 and plays a key role in the quality of college education, while others see it as adding to the burden on colleges. Denis Rousseau, president of the CEEC for the past three years, is clear about the contrasting perceptions of the organization. He is nevertheless convinced of the relevance and usefulness of an independent commission within the college network. His diversified career path, notably as a literature teacher, union executive member, academic dean and then director general, gives him a keen understanding of the issues and opportunities specific to the CEEC. On the organization’s 30th anniversary, he looks back at past achievements, challenges met, and future directions." -- AQP

Abrupt Climate changes Recorded in Loess Sequences

The terrestrial sediments known as "loess" represent an important archive of paleoclimatic variability. Mineral material mobilized by wind at the ground surface was transported over distances from a few hundred to thousands of kilometers and deposited back on the ground where it underwent a gradual transformation into loess sediment. The largest loess deposits are found in the Northern Hemisphere, primarily because the continental surface is much larger than the Southern Hemisphere. Depending on their location on the globe, the deposits have formed under the influence of different climate factors, and contain more or less detailed records of regional climate change. here we review the current knowledge about the three main loess regions of the Northern Hemisphere. The many underlying references are provided in an extensive online archive of references, listed by regions

Structural characterization of oxidized dimeric Scapharca inaequivalvis hemoglobin by resonance Raman spectroscopy.

Resonance Raman spectra of the ferric homodimeric hemoglobin from Scapharca inaequivalvis have been measured over the pH range 5.8-8.3 in buffers of ionic strengths 0.01 and 0.1 M to determine the spin and coordination state of the iron atom. Three species contribute to the spectra: a low spin hexacoordinate, a high spin pentacoordinate, and a high spin hexacoordinate component. Optical absorption and EPR spectra measured under the same conditions allowed the identification of the ligands in the sixth coordination position, namely the distal histidine in the low spin derivative and a water molecule in the high spin one. The relative concentrations of these three species depend on pH in an unusual way. Thus, the aquomet derivative is present over the whole pH range, albeit in small amounts as most of the hemoglobin converts to the low spin hemichrome at acid pH values and to the pentacoordinate derivative at neutral and slightly alkaline ones. The formation of a pentacoordinate heme as the pH is increased has not been reported previously for other myoglobins and hemoglobins. Low ionic strength and high protein concentration favor the formation of the high spin pentacoordinate species, while at high ionic strength and low protein concentration the low spin hexacoordinate species prevails. Ionization of the iron-bound water molecule occurs at pH > or = 9.3; accordingly, signals from the hydroxyl derivative were not observed in the Raman spectra over the pH range studied

A Punctuated Equilibrium Analysis of the Climate Evolution of Cenozoic: Hierarchy of Abrupt Transitions

The Earth's climate has experienced numerous critical transitions during its history, which have often been accompanied by massive and rapid changes in the biosphere. Such transitions are evidenced in various proxy records covering different timescales. The goal is then to identify, date, and rank past critical transitions in terms of importance, thus possibly yielding a more thorough perspective on climatic history. To illustrate such an angle, which inspired the punctuated equilibrium angle on the theory of evolution, we have analyzed 2 key high-resolution datasets: the CENOGRID marine compilation (past 66 Myr), and North Atlantic U1308 record (past 3.3 Myr). By combining recurrence analysis of the individual time series with a multivariate representation of the system based on the theory of the quasi-potential, we identify the key abrupt transitions associated with major regime changes that differentiate various clusters of climate variability. This allows interpreting the time-evolution of the system as a trajectory taking place in a dynamical landscape, whose multiscale features are associated with a hierarchy of tipping points.Comment: 27 pages, 5 figures plus supplementary materia

Redox-Controlled Proton Gating in Bovine Cytochrome c Oxidase

Cytochrome c oxidase is the terminal enzyme in the electron transfer chain of essentially all organisms that utilize oxygen to generate energy. It reduces oxygen to water and harnesses the energy to pump protons across the mitochondrial membrane in eukaryotes and the plasma membrane in prokaryotes. The mechanism by which proton pumping is coupled to the oxygen reduction reaction remains unresolved, owing to the difficulty of visualizing proton movement within the massive membrane-associated protein matrix. Here, with a novel hydrogen/deuterium exchange resonance Raman spectroscopy method, we have identified two critical elements of the proton pump: a proton loading site near the propionate groups of heme a, which is capable of transiently storing protons uploaded from the negative-side of the membrane prior to their release into the positive side of the membrane and a conformational gate that controls proton translocation in response to the change in the redox state of heme a. These findings form the basis for a postulated molecular model describing a detailed mechanism by which unidirectional proton translocation is coupled to electron transfer from heme a to heme a 3, associated with the oxygen chemistry occurring in the heme a 3 site, during enzymatic turnover

Mineral magnetic characterization of the Upper Pleniglacial Nussloch loess sequence (Germany): an insight into local environmental processes

International audience(1) First comprehensive environmental magnetism study of the Nussloch (Rhine River Valley, Germany) loess/palaeosol deposit. (2) Bulk ferrimagnetic concentration parameters are dominantly controlled by variations in coarse-grained MD ferrimagnetic particles of detrital aeolian origin. (3) The imprint of waterlogging-induced redoxomorphic processes on the magnetic record is observed by dissolution of fine-grained magnetic minerals. (4) The interpretation of magnetic susceptibility variations alone within loess and palaeosol deposits following the wind-vigour or pedogenic enhancement models will be hindered by waterlogging-induced redoxomorphic processes, if present. S U M M A R Y Presently, most loess/palaeosol magnetic susceptibility records are interpreted as following either the wind-vigour model or the pedogenic enhancement model. However redoxomorphic processes induced by waterlogging, often referred to gleying in the loess literature, are also known to alter loess deposits but their impact on loess/palaeosol magnetic susceptibility records has received little attention. The reported rock magnetic study aims to characterize the mineral magnetic response of loess to waterlogging-induced redoxomorphic processes, thus improving our understanding of mineral magnetic changes within loess deposits with respect to environmental and climate conditions. The Nussloch loess-palaeosol deposit (Rhine Valley, Germany) was targeted because it is one of the best-studied Pleniglacial deposits for Western Europe in which numerous tundra gley intervals have been identified. Moreover, a comprehensive high-resolution environmental magnetism study has never been undertaken for this site. Various rock magnetism experiments were conducted at both room and low temperatures to characterise the composition, concentration and relative magnetic grain size of the mineral magnetic assemblage. The relative changes in magnetic parameters within the investigated loess interval are primarily controlled by (1) varying concentrations of coarse-grained ferri-magnetic particles of detrital (aeolian) origin and (2) dissolution of fine-grained ferrimagnetic particles related to in situ post-depositional alteration promoted by waterlogging-induced re-doxomorphic processes. Goethite is found to be ubiquitous throughout the studied interval and is argued to have both a primary (aeolian) and secondary (in situ) origin. We conclude, that redoxomorphic processes induced by waterlogging, if present, will hinder the interpretation of magnetic susceptibility variations within loess and palaeosol deposits following the expected relationships dictated by the wind-vigour and the pedogenic enhancement magnetism models

Present and Past Mineral Dust Variations- a Cross-Disciplinary Challenge for Research

In its recently published report, the intergovernmental Panel Climate Change identified the role of mineral dust in the Earth system and the uncertainties it introduces to the total aerosol radiative forcing and climate projections as key topics for future research. Achieving a thorough understanding of feedback associated with eolian dust is a challenge for a number of Earth science disciplines as mineral dust processes operate on a wide range of spatial and temporal scales. On the other hand, studies of mineral dust contribute significantly to research on past climatic and environment conditions enabled by dust preserved in different kinds of depositional paleoclimate archives.Such work has been the focus of PAGES' recently concluded ADOM (Atmospheric Dust during the last glacial cycle: Observations and Modeling) working, which was established in 2008 with the goal of combining reconstructions of climate and atmospheric circulation from terrestrial, marine and ice-core records with modern dust evidence and model simulations of past and present atmospheric circulation