Perfil de los extensionistas rurales argentinos del sistema público

Pese la importancia de la extensión rural en toda estrategia orientada el desarrollo de los sectores de productores rurales pequeños y medianos, no existen en la Argentina trabajos académicos que reconstruyan de manera completa y sistemática el perfil de quienes trabajan en el país en extensión rural. Por esta razón, se realizó una investigación cuantitativa descriptiva de carácter transversal que permitió reconstruir el perfil de los extensionistas rurales que trabajan en el sistema de extensión público argentino. Para este fin se realizó una encuesta (enviada vía email) a extensionistas del INTA, ProHuerta y de la Subsecretaría de Agricultura Familiar. Los resultados de esta investigación permitieron aportar, a partir del uso de herramientas estadísticas, a la descripción del perfil de los extensionistas rurales que trabajan en la Argentina, así como a la del perfil diferencial de hombres y mujeres y de quienes trabajan en las diferentes instituciones

El Ordo ad dandam poenitentiam del abad Regino de Prüm

El trabajo a continuación tiene como objetivo presentar una traducción del Ordo ad dandam poenitentiam de Regino de Prüm (ca. 840-915). Este cuestionario confesional formaba parte de la colección canónica Libri duo de synodalibus causis et disciplinis ecclesiasticis y sirvió de base para el conocido penitencial del obispo Burchard de Worms, el Corrector sive medicus, redactado casi un siglo después. La obra de Regino no ha sido aún traducida a lenguas modernas, con excepción de una traducción parcial en lengua alemana

Perfil de los extensionistas rurales argentinos del sistema público

Pese la importancia de la extensión rural en toda estrategia orientada el desarrollo de los sectores de productores rurales pequeños y medianos, no existen en la Argentina trabajos académicos que reconstruyan de manera completa y sistemática el perfil de quienes trabajan en el país en extensión rural. Por esta razón, se realizó una investigación cuantitativa descriptiva de carácter transversal que permitió reconstruir el perfil de los extensionistas rurales que trabajan en el sistema de extensión público argentino. Para este fin se realizó una encuesta (enviada vía email) a extensionistas del INTA, ProHuerta y de la Subsecretaría de Agricultura Familiar. Los resultados de esta investigación permitieron aportar, a partir del uso de herramientas estadísticas, a la descripción del perfil de los extensionistas rurales que trabajan en la Argentina, así como a la del perfil diferencial de hombres y mujeres y de quienes trabajan en las diferentes instituciones

El Ordo ad dandam poenitentiam del abad Regino de Prüm

El trabajo a continuación tiene como objetivo presentar una traducción del Ordo ad dandam poenitentiam de Regino de Prüm (ca. 840-915). Este cuestionario confesional formaba parte de la colección canónica Libri duo de synodalibus causis et disciplinis ecclesiasticis y sirvió de base para el conocido penitencial del obispo Burchard de Worms, el Corrector sive medicus, redactado casi un siglo después. La obra de Regino no ha sido aún traducida a lenguas modernas, con excepción de una traducción parcial en lengua alemana

Biogeochemistry of the Darwin Mounds, NE Atlantic

The Darwin Mounds are a series of small (<=5 m high, 75-100 m diameter) sandy features located in the northern Rockall Trough. They provide a habitat for communities of Lophelia pertusa and associated fauna. Suspended particulate organic matter (sPOM) reaching the deep-sea floor, which could potentially fuel this deep-water coral (DWC) ecosystem, was collected during summer 2000. This was relatively "fresh" (i.e. dominated by labile lipids such as polyunsaturated fatty acids) and was derived largely from phytoplankton remains and faecal pellets, with contributions from bacteria and microzooplankton. Labile sPOM components were enriched in the benthic boundary layer (~10 m above bottom (mab)) relative to 150 mab. The action of certain benthic fauna that are exclusively associated with the DWC ecosystem (e.g. echiuran worms) leads to the subduction of fresh organic material into the sediments. The mound surface sediments are enriched in organic carbon, relative to off-mound sites. There is no evidence for hydrocarbon venting at this location.

Benthonic foraminifera of ODP Site 116-717

We report on benthic foraminifer results from Site 717 in the Distal Bengal Fan. Only 80 out of 380 samples contained useful benthic foraminifer information. However, we were able to identify four assemblages: 1. A present-day one dominated by Nuttallides umbonifera with some North Atlantic species; 2. An agglutinated fauna consisting of one species; 3. A reworked assemblage consisting of shallow-water forms; and 4. A reworked fauna consisting of an abundance of all kinds of forms including Cretaceous species. The reworked assemblage 4, we believe, represents a period when fan sediments were blocked from this area by east-west trending intraplate deformation. In the remainder of the core section, sedimentation appears to be dominated by Fan deposition with abundant terrestrial debris. In the infrequent pelagic intervals, it appears that abyssal water masses changed little since the late Miocene.

Biogeochemical measurements associated to deep-sea wood falls

Large organic food falls to the deep sea - such as whale carcasses and wood logs - support the development of reduced, sulfidic niches in an otherwise oxygenated, oligotrophic deep-sea environment. These transient hot spot ecosystems may serve the dispersal of highly adapted chemosynthetic organisms such as thiotrophic bivalves and siboglinid worms. Here we investigated the biogeochemical and microbiological processes leading to the development of sulfidic niches. Wood colonization experiments were carried out for the duration of one year in the vicinity of a cold seep area in the Nile deep-sea fan (Eastern Mediterranean) at depths of 1690 m. Wood logs were deployed in 2006 during the BIONIL cruise (RV Meteor M70/2 with ROV Quest, Marum, Germany) and sampled in 2007 during the Medeco-2 cruise (RV Pourquoi Pas? with ROV Victor 6000, Ifremer, France). Wood-boring bivalves played a key role in the initial degradation of the wood, the dispersal of wood chips and fecal matter around the wood log, and the provision of colonization surfaces to other organisms. Total oxygen uptake measured with a ROV-operated benthic chamber module was higher at the wood (0.5 m away) in contrast to 10 m away at a reference site (25 mmol m-2 d-1 and 1 mmol m-2 d-1, respectively), indicating an increased activity of sedimentary communities around the wood falls. Bacterial cell numbers associated with wood increased substantially from freshly submerged wood to the wood chip/fecal matter layer next to the wood experiments, as determined with Acridine Orange Direct Counts (AODC) and DAPI-stained counts. Microsensor measurements of sulfide, oxygen and pH were conducted ex situ. Sulfide fluxes were higher at the wood experiments when compared to reference measurements (19 and 32 mmol m-2 d-1 vs. 0 and 16 mmol -2 d-1, respectively). Sulfate reduction (SR) rates at the wood experiments were determined in ex situ incubations (1.3 and 2.0 mmol m-2 d-1) and fell into the lower range of SR rates previously observed from other chemosynthetic habitats at cold seeps. There was no influence of wood deposition on phosphate, silicate and nitrate concentrations, but ammonium concentrations were elevated at the wood chip-sediment boundary layer. Concentrations of dissolved organic carbon were much higher at the wood experiments (wood chip-sediment boundary layer) in comparison to measurements at the reference sites, which may indicate that cellulose degradation was highest under anoxic conditions and hence enabled by anaerobic benthic bacteria, e.g. fermenters and sulfate reducers. Our observations demonstrate that, after one year, the presence of wood at the seafloor had led to the creation of sulfidic niches, comparable to what has been observed at whale falls, albeit at lower rates.

Time series of zooplankton abundance at station L4 in the English Channel from 1988 to 2011

Ongoing zooplankton research at the Plymouth Marine Laboratory has established a time series of zooplankton species since 1988 at L4, a coastal station off Plymouth. Samples were collected by vertical net hauls (WP2 net, mesh 200 µm; UNESCO 1968) from the sea floor (approximately 50 m) to the surface and stored in 4% formalin. Much of the zooplankton analysis has been to the level of "major taxonomic groups" only, and a number of different analysts have participated over the years. The level of expertise has generally been consistent, but the user should be aware that levels of taxonomic discrimination may vary during the course of the dataset. The dominant calanoid copepods are generally well discriminated to species throughout. Calanus has not been routinely examined for species determination, the assumption being that the local population is entirely composed of Calanus helgolandicus. In certain years there has been a particular interest in Temora stylifera, Centropages cherchiae and other species reflected in the dataset. The lack of records in other previous years does not necessarily reflect species absence. We view it as essential for all users of L4 plankton data to establish and maintain contact with the nominated current data originators as well as fully consulting the metadata. While not impinging on free data access, this ensures that this large, species-rich but slightly complex species database is being used in the correct way, and any potential issues with the data are clarified. Furthermore, a proper dialogue with these local experts on the time series will enable where appropriate the most recent sampling timepoints to be used. The data can be downloaded from BODC or from doi:10.1594/PANGAEA.778092 as files for each year by searching for "L4 zooplankton". The most comprehensive dataset is the version downloadable directly from this page. The entire set of zooplankton samples is stored at the Plymouth Marine Laboratory in buffered formalin, and may be available for further taxonomic analysis on request.

AMS 14C ages and isotopic compositions of samples from the Derugin Basin, Sea of Okhotsk

An area of massive barite precipitations was studied at a tectonic horst in 1500 m water depth in the Derugin Basin, Sea of Okhotsk. Seafloor observations and dredge samples showed irregular, block- to column-shaped barite build-ups up to 10 m high which were scattered over the seafloor along an observation track 3.5 km long. High methane concentrations in the water column show that methane expulsion and probably carbonate precipitation is a recently active process. Small fields of chemoautotrophic clams (Calyptogena sp., Acharax sp.) at the seafloor provide additional evidence for active fluid venting. The white to yellow barites show a very porous and often layered internal fabric, and are typically covered by dark-brown Mn-rich sediment; electron microprobe spectroscopy measurements of barite sub-samples show a Ba substitution of up to 10.5 mol% of Sr. Rare idiomorphic pyrite crystals (~1%) in the barite fabric imply the presence of H2S. This was confirmed by clusters of living chemoautotrophic tube worms (1 mm in diameter) found in pores and channels within the barite. Microscopic examination showed that micritic aragonite and Mg-calcite aggregates or crusts are common authigenic precipitations within the barite fabric. Equivalent micritic carbonates and barite carbonate cemented worm tubes were recovered from sediment cores taken in the vicinity of the barite build-up area. Negative d13C values of these carbonates (>-43.5 per mill PDB) indicate methane as major carbon source; d18O values between 4.04 and 5.88 per mill PDB correspond to formation temperatures, which are certainly below 5°C. One core also contained shells of Calyptogena sp. at different core depths with 14C-ages ranging from 20 680 to >49 080 yr. Pore water analyses revealed that fluids also contain high amounts of Ba; they also show decreasing SO4**2- concentrations and a parallel increase of H2S with depth. Additionally, S and O isotope data of barite sulfate (d34S: 21.0-38.6 per mill CDT; d18O: 9.0-17.6 per mill SMOW) strongly point to biological sulfate reduction processes. The isotope ranges of both S and O can be exclusively explained as the result of a mixture of residual sulfate after a biological sulfate reduction and isotopic fractionation with 'normal' seawater sulfate. While massive barite deposits are commonly assumed to be of hydrothermal origin, the assemblage of cheomautotrophic clams, methane-derived carbonates, and non-thermally equilibrated barite sulfate strongly implies that these barites have formed at ambient bottom water temperatures and form the features of a Giant Cold Seep setting that has been active for at least 49 000 yr.

Mesopelagic fish abundance and particle size spectrum analysis from Maria S. Merian cruise MSM26, spring 2013

One of the goals of EU BASIN is to understand variability in production across the Atlantic and the impact of this variability on higher trophic levels. One aspect of these investigations is to examine the biomes defined by Longhurst (2007). These biomes are largely based on productivity measured with remote sensing. During MSM 26, mesopelagic fish and size-spectrum data were collected to test the biome classifications of the north Atlantic. In most marine systems, the size-spectrum is a decay function with more, smaller organisms and fewer larger organisms. The intercept of the size-spectrum has been linked to overall productivity while the slope represents the "rate of decay" of this productivity (Zhou 2006, doi:10.1093/plankt/fbi119). A Laser In-Situ Scattering Transmissometer was used to collect size-spectrum data and net collections were made to capture mesopelagic fish. The relationship among the mesopelagic fish size and abundance distributions will be compared to the estimates of production from the size-spectrum data to evaluate the biomes of the stations occupied during MSM 26.