The information system of the French Peatland Observation Service: Service National d'Observation Tourbières – A valuable tool to assess the impact of global changes on the hydrology and biogeochemistry of temperate peatlands through long term monitoring

Mitigating and adapting to global changes requires a better understanding of the response of the Biosphere to these environmental variations. Human disturbances and their effects act in the long term (decades to centuries) and consequently, a similar time frame is needed to fully understand the hydrological and biogeochemical functioning of a natural system. To this end, the ‘Centre National de la Recherche Scientifique’ (CNRS) promotes and certifies long-term monitoring tools called national observation services or ‘Service National d'Observation’ (SNO) in a large range of hydrological and biogeochemical systems (e.g., cryosphere, catchments, aquifers). The SNO investigating peatlands, the SNO ‘Tourbières’, was certified in 2011 ( https://www.sno-tourbieres.cnrs.fr/ ). Peatlands are mostly found in the high latitudes of the northern hemisphere and French peatlands are located in the southern part of this area. Thus, they are located in environmental conditions that will occur in northern peatlands in coming decades or centuries and can be considered as sentinels. The SNO Tourbières is composed of four peatlands: La Guette (lowland central France), Landemarais (lowland oceanic western France), Frasne (upland continental eastern France) and Bernadouze (upland southern France). Thirty target variables are monitored to study the hydrological and biogeochemical functioning of the sites. They are grouped into four datasets: hydrology, fluvial export of organic matter, greenhouse gas fluxes and meteorology/soil physics. The data from all sites follow a common processing chain from the sensors to the public repository. The raw data are stored on an FTP server. After operator or automatic processing, data are stored in a database, from which a web application extracts the data to make them available ( https://data-snot.cnrs.fr/data-access/ ). Each year at least, an archive of each dataset is stored in Zenodo, with a digital object identifier (DOI) attribution ( https://zenodo.org/communities/sno_tourbieres_data/ ).     

Fluvial incisions in the North‐Western Pyrenees (Aspe Valley): Dissection of a former planation surface and some tectonic implications

Dissected remnants of a high elevation low relief surface (HELRS) are encountered all along the Pyrenean range. All authors agree that the HELRS was shaped during the post‐shortening evolution of the belt, but doubt remains on its original elevation. Notably, whether a post‐shortening uplift event occurred after the generation of the Pyrenean planation surface is still debated. Based on a geomorphological study of the entrenchment of the Aspe River in the North‐Western Pyrenees, we describe a post‐Oligocene multi‐stage dissection of the HELRS linked to a regional post‐shortening uplift. Each incision stage is recorded by erosional triangular facets and associated stepped remnants of former smooth topographies. Compared analysis of patterns of incision in the Axial Zone and its northern border allows to evidence differential vertical motions. We discuss the forcing mechanism(s) that controlled this morphological evolution.     

Chondrules in CK carbonaceous chondrites and thermal history of the CV–CK parent body

CK chondrites are the only group of carbonaceous chondrites with petrologic types ranging from 3 to 6. It is commonly reported than ~15 vol% of CK4–6 samples are composed of chondrules. The modal abundance of chondrules estimated here for 18 CK3–6 (including five CK3s) ranges from zero (totally recrystallized) to 50.5%. Although almost all chemically re‐equilibrated with the host matrix, we recognized in CK3s and Tanezrouft (Tnz) 057 (CK4) up to 85% of chondrules as former type I chondrules. Mean diameters of chondrules range from 0.22 to 1.05 mm for Karoonda (CK4) and Tnz 057 (CK4), respectively. Up to ~60% of chondrules in CK3–4 are surrounded by igneous rims (from ~20 μm to 2 mm width). Zoned olivines were found in unequilibrated chondrules from DaG 431 (CK3‐an), NWA 4724 (CK3.8), NWA 4423 (CK3.9), and Tnz 057 (CK4). We modeled Fe/Mg interdiffusion profiles measured in zoned olivines to evaluate the peak metamorphic temperatures and time scales of the CK parent body metamorphism, and proposed a two‐stage diffusion process in order to account for the position of inflection points situated within chondrules. Time scales inferred from Fe/Mg interdiffusion in olivine from unequilibrated chondrules are on the order of tens to a hundred thousand years (from 50 to 70,000 years for peak metamorphic temperatures of 1140 and 920 K, respectively). These durations are longer than what is commonly accepted for shock metamorphism and shorter than what is required for nuclide decay. Using the concept of a continuous CV–CK metamorphic series, which is reinforced by this study, we estimated peak metamorphic temperatures <850 K for CV, 850–920 K for CK3, and 920–1140 K for CK4–6 chondrites considering a duration of 70,000 years.     

Site effects of the Roio basin, L��Aquila

During the microzonation studies of the April 6th, 2009 L??Aquila earthquake, we observed local seismic amplifications in the Roio area??a plane separated from L??Aquila city center by mount Luco. Six portable, digital instruments were deployed across the plain from 15 April to mid-May 2009. This array recorded 152 aftershocks. We analyzed the ground motion from these events to determine relative site amplification within the plain and on surrounding ridges. Horizontal over vertical spectral ratio on noise data (HVSRN), aftershock recordings (HVEQ) and standard spectral ratio (SSR) showed amplifications at 1.3 and 4.0?Hz on quaternary deposits. Seismic amplifications in the frequency range of 4 and 6?Hz were also observed on a carbonate ridge of Colle di Roio, on the northwestern border of the plateau. A small amplification was noticed near the top of mount Luco, another rocky site. Large discrepancies in the amplification levels between methods have been observed for these sites, but the HVSRN, HVEQ and SSR gave similar results at the stations located in the Roio plain. On the rocky sites, the SSR was more reliable than the HVSRN at estimating the transfer function of the site, even if the resonance frequency seemed to be well detected by the latter method.     

Evolution of anthropogenic and biomass burning emissions of air pollutants at global and regional scales during the 1980�C2010 period

Several different inventories of global and regional anthropogenic and biomass burning emissions are assessed for the 1980?C2010 period. The species considered in this study are carbon monoxide, nitrogen oxides, sulfur dioxide and black carbon. The inventories considered include the ACCMIP historical emissions developed in support of the simulations for the IPCC AR5 assessment. Emissions for 2005 and 2010 from the Representative Concentration Pathways (RCPs) are also included. Large discrepancies between the global and regional emissions are identified, which shows that there is still no consensus on the best estimates for surface emissions of atmospheric compounds. At the global scale, anthropogenic emissions of CO, NO_x and SO₂ show the best agreement for most years, although agreement does not necessarily mean that uncertainty is low. The agreement is low for BC emissions, particularly in the period prior to 2000. The best consensus is for NO_x emissions for all periods and all regions, except for China, where emissions in 1980 and 1990 need to be better defined. Emissions of CO need better quantification in the USA and India for all periods; in Central Europe, the evolution of emissions during the past two decades needs to be better determined. The agreement between the different SO₂ emissions datasets is rather good for the USA, but better quantification is needed elsewhere, particularly for Central Europe, India and China. The comparisons performed in this study show that the use of RCP8.5 for the extension of the ACCMIP inventory beyond 2000 is reasonable, until more global or regional estimates become available. Concerning biomass burning emissions, most inventories agree within 50?C80%, depending on the year and season. The large differences between biomass burning inventories are due to differences in the estimates of burned areas from the different available products, as well as in the amount of biomass burned.     

Segmentation and kinematics of the North America‐Caribbean plate boundary offshore Hispaniola

We explored the submarine portions of the Enriquillo–Plantain Garden Fault zone (EPGFZ) and the Septentrional–Oriente Fault zone (SOFZ) along the Northern Caribbean plate boundary using high‐resolution multibeam echo‐sounding and shallow seismic reflection. The bathymetric data shed light on poorly documented or previously unknown submarine fault zones running over 200 km between Haiti and Jamaica (EPGFZ) and 300 km between the Dominican Republic and Cuba (SOFZ). The primary plate‐boundary structures are a series of strike‐slip fault segments associated with pressure ridges, restraining bends, step overs and dogleg offsets indicating very active tectonics. Several distinct segments 50–100 km long cut across pre‐existing structures inherited from former tectonic regimes or bypass recent morphologies formed under the current strike‐slip regime. Along the most recent trace of the SOFZ, we measured a strike‐slip offset of 16.5 km, which indicates steady activity for the past ~1.8 Ma if its current GPS‐derived motion of 9.8 ± 2 mm a^?1 has remained stable during the entire Quaternary.     

The effect of sideband ratio on line intensity for Herschel/HIFI

The Heterodyne Instrument for the Far Infrared (HIFI) on board the Herschel Space Observatory is composed of a set of fourteen double sideband mixers. We discuss the general problem of the sideband ratio (SBR) determination and the impact of an imbalanced sideband ratio on the line calibration in double sideband heterodyne receivers. The HIFI SBR is determined from a combination of data taken during pre-launch gas cell tests and in-flight. The results and some of the calibration artefacts discovered in the gas cell test data are presented here along with some examples of how these effects appear in science data taken in orbit.     

In-flight calibration of the HIFI diplexers

HIFI is a heterodyne spectrometer aboard the Herschel Space Observatory, providing high-spectral-resolution capabilities. Of its seven frequency bands, four (bands 3, 4, 6, and 7) employ Martin-Puplett diplexers to combine sky signal and local oscillator at the two linear polarizations H and V, prior to feeding them into the mixers (receivers). The optical path difference in each of these 8 diplexers must be tuned to the observed frequency. The required actuator currents were determined in flight before the start of routine science observations. We here report on regular (roughly quarterly) engineering test observations to validate the repeatability of the HIFI diplexers during the routine phase of Herschel operations. We find the optical path difference to be stable to within 0.4 % of the relevant wavelength, typically at the sub-micron level. We conclude that the repeatability and precision of the diplexer tuning mechanism are so high that science data are in no way negatively affected. With the diplexer calibration established and validated, this line of reasoning can be reversed, and the diplexers can be used as relative spectrometers to measure the local-oscillator frequency, i.e., to check the spectral purity of the local oscillator across the diplexer bands. This was done from before launch out to the last months of cryogenic operations in space.     

Biogeography of the deep-sea galatheid squat lobsters of the Pacific Ocean

We analyzed the distribution patterns of the galatheid squat lobsters (Crustacea, Decapoda, Galatheidae) of the Pacific Ocean. We used the presence/absence data of 402 species along the continental slope and continental rise (200–2000 m) obtained from 54 cruises carried out in areas around the Philippines, Indonesia, Solomon, Vanuatu, New Caledonia, Fiji, Tonga, Wallis and Futuna and French Polynesia. The total number of stations was ca. 3200. We also used published data from other expeditions carried out in the Pacific waters, and from an exhaustive search of ca. 600 papers on the taxonomy and biogeography of Pacific species. We studied the existence of biogeographic provinces using multivariate analyses, and present data on latitudinal and longitudinal patterns of species richness, rate of endemism and the relationship between body sizes with the size of the geographic ranges. Latitudinal species richness along the Western and Eastern Pacific exhibited an increase from higher latitudes towards the Equator. Longitudinal species richness decreased considerably from the Western to the Central Pacific. Size frequency distribution for body size was strongly shifted toward small sizes and endemic species were significantly smaller than non-endemics. This study concludes that a clear separation exists between the moderately poor galatheid fauna of the Eastern Pacific and the rich Western and Central Pacific faunas. Our results also show that the highest numbers of squat lobsters are found in the Coral Sea (Solomon-Vanuatu-New Caledonia islands) and Indo-Malay-Philippines archipelago (IMPA). The distribution of endemism along the Pacific Ocean indicates that there are several major centres of diversity, e.g. Coral Sea, IMPA, New Zealand and French Polynesia. The high proportion of endemism in these areas suggests that they have evolved independently.