Local remineralization patterns in the mesopelagic zone of the Eastern North Atlantic, off the NW Iberian Peninsula

Original research articleThe short-time-scale variability of the remineralization patterns in the domain of Eastern North Atlantic Central Waters (ENACW) off the NW Iberian Peninsula is studied based on biogeochemical data (oxygen, nutrient salts, total alkalinity, pH, dissolved organic matter and fluorescence of dissolved humic substances) collected weekly between May 2001 and April 2002. The temporal variability of inorganic variables points to an intensification of remineralization during the summer and autumn, with an increase of nutrients, total inorganic carbon and fluorescence and a decrease of oxygen. During the subsequent winter mixing, there is a biogeochemical reset of the system, with lower nutrients, total inorganic carbon and fluorescence and higher oxygen. In contrast to inorganic variables, the levels of dissolved organic matter in the ENACW seem to respond to short-term events probably associated with fast sinking particles, where solubilisation of organic matter prevails over remineralization. Applying a previously published stoichiometric model, we observed a vertical fractionation of organic-matter remineralization. Although there is a preferential remineralization of proteins and P compounds in the entire domain of ENACW, the percentage was higher in the upper ENACW (σ80% for the upper ENACW and 63% for the lower. Likewise, the redissolution of calcareous structures contributes about 6% and 13% to the carbon regenerated in the upper and lower layers of ENACW, respectively.Financial support for this work came from CICYT project MAR99-1039-C02-01; a contract of the Ramón y Cajal programme of the Spanish MCYT and a fellowship from the Spanish MCYT.Versión del edito

Fluorescence: Absorption coefficient ratio — Tracing photochemical and microbial degradation processes affecting coloured dissolved organic matter in a coastal system

Original research paperThe optical properties of coloured dissolved organic matter (CDOM) – absorption coefficient, induced fluorescence, and fluorescence quantum yield – were determined in the coastal eutrophic system of the Ría de Vigo (NW Spain) under two contrasting situations: a downwelling event in September 2006 and an upwelling event in June 2007. Significantly different optical properties were recorded in the shelf surface (higher absorption coefficient and lower quantum yield) and bottom (lower absorption coefficient and higher quantum yield) waters that entered the embayment during downwelling and upwelling conditions, respectively. Continental waters presented distinctly high CDOM levels. The spatial and temporal variability of the induced fluorescence to absorption coefficient ratio during the mixing of shelf and continental waters was used to quantify the relative importance of photochemical and microbial processes under these contrasting hydrographic conditions. Photochemical processes were dominant during the downwelling episode: 86% of the variability of CDOM can be explained by photochemical degradation. On the contrary, microbial processes prevailed during the upwelling event: 77% of the total variability of CDOM was explained by microbial respiration.The Xunta de Galicia, grant number PGIDIT-05MA40201PR; the project SUMMER, grant number CTM2008-03309/MAR; a I3P-CSIC predoctoral fellowship and a Marie Curie I.O.F.Versión del editor2,75

La enfermedad de la punta negra del trigo

La enfermedad de la Punta Negra del trigo se caracteriza por la aparición, en los granos afectados, de un oscurecimiento en la zona del embrión que da nombre a la enfermedad. Los síntomas más frecuentes consisten en la decoloración del extremo embrionario de la semilla, pasando del marrón oscuro al negro con la posibilidad de extenderse hacia el endospermo. La susceptibilidad varietal así como el manejo del riego parecen ser los factores claves en el control de la enfermedad

Application of a stochastic weather generator to assess climate change impacts in a semi-arid climate: The Upper Indus Basin

Assessing local climate change impacts requires downscaling from Global Climate Model simulations. Here, a stochastic rainfall model (RainSim) combined with a rainfall conditioned weather generator (CRU WG) have been successfully applied in a semi-arid mountain climate, for part of the Upper Indus Basin (UIB), for point stations at a daily time-step to explore climate change impacts. Validation of the simulated time-series against observations (1961–1990) demonstrated the models’ skill in reproducing climatological means of core variables with monthly RMSE of <2.0 mm for precipitation and ⩽0.4 °C for mean temperature and daily temperature range. This level of performance is impressive given complexity of climate processes operating in this mountainous context at the boundary between monsoonal and mid-latitude (westerly) weather systems. Of equal importance the model captures well the observed interannual variability as quantified by the first and last decile of 30-year climatic periods. Differences between a control (1961–1990) and future (2071–2100) regional climate model (RCM) time-slice experiment were then used to provide change factors which could be applied within the rainfall and weather models to produce perturbed ‘future’ weather time-series. These project year-round increases in precipitation (maximum seasonal mean change:+27%, annual mean change: +18%) with increased intensity in the wettest months (February, March, April) and year-round increases in mean temperature (annual mean +4.8 °C). Climatic constraints on the productivity of natural resource-dependent systems were also assessed using relevant indices from the European Climate Assessment (ECA) and indicate potential future risk to water resources and local agriculture. However, the uniformity of projected temperature increases is in stark contrast to recent seasonally asymmetrical trends in observations, so an alternative scenario of extrapolated trends was also explored. We conclude that interannual variability in climate will continue to have the dominant impact on water resources management whichever trajectory is followed. This demonstrates the need for sophisticated downscaling methods which can evaluate changes in variability and sequencing of events to explore climate change impacts in this region

Response of phytoplankton to enhanced atmospheric and riverine nutrient inputs in a coastal upwelling embayment

Original research paperOver the past decades, as a consequence of human activity, there was an increase in nutrient inputs to the ocean and they are expected to enhance even more in the future. Coastal areas, accounting for a significant proportion of marine primary productivity, are the most vulnerable zones to anthropogenic impacts. The response of phytoplankton communities to an increase in organic and inorganic nutrients levels from natural allochthonous sources was assessed in microcosm experiments conducted in a coastal system affected by intermittent upwelling events (Ría de Vigo, NW Iberia). Three nutrient addition experiments were performed in spring, summer and autumn, when surface water was supplemented with 5 and 10% of atmospheric and riverine matter. Pico-, nano- and microphytoplankton abundances, chlorophyll a concentration (Chl a) and primary production rates (PP) were measured and compared with those in the control seawater sample (without additions) after 48 h of incubation. Simultaneous experiments with controlled additions of inorganic and organic nutrients were also performed in order to describe the limiting nutrient for phytoplankton growth at each experiment. The composition of the matter inputs and the structure of the phytoplankton communities determined the type of response observed. Phytoplankton responses varied among seasons, being positively correlated with dissolved inorganic nitrogen (DIN) concentrations. As expected, the phytoplankton responses to external nutrient inputs were stronger under low nutrient levels (summer) than when phytoplankton was already growing in nutrient replete conditions (spring). Null and negative responses to the natural inputs were observed in autumn, which suggests that the oceanic phytoplankton advected to this coastal system during downwelling events could be occasionally inhibited by these nutrient inputs. In a future global change scenario, characterized by enhanced nutrient inputs from riverine and atmospheric origin, the response of phytoplankton communities will strongly depend on the concentration and chemical composition of these inputs and on the structure of phytoplankton communities able to respond to themSpanish Ministry of Science and Innovation (project REIMAGE CTM2011-30155); Spanish Ministry of Economy and Competitiviness (project iSmall, reference CTM2014-56119-R); Portuguese Foundation for Science and Technology (reference SFRH/BPD/188485/2015); ESF (reference JAE DOC 040) and MINECO (project FERMIO reference CTM2014-57334-JIN)Versión del edito

Transitions of cardio-metabolic risk factors in the Americas between 1980 and 2014

Describing the prevalence and trends of cardiometabolic risk factors that are associated with non-communicable diseases (NCDs) is crucial for monitoring progress, planning prevention, and providing evidence to support policy efforts. We aimed to analyse the transition in body-mass index (BMI), obesity, blood pressure, raised blood pressure, and diabetes in the Americas, between 1980 and 2014

Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

TRY plant trait database – enhanced coverage and open access

Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives