Potential for seasonal prediction of the Atlantic sea surface temperatures using the RAPID array at 26°N

The Atlantic meridional overturning circulation (AMOC) plays a critical role in the climate system and is responsible for much of the meridional heat transported by the ocean. In this paper, the potential of using AMOC observations from the 26 ∘ N RAPID array to predict North Atlantic sea surface temperatures is investigated for the first time. Using spatial correlations and a composite method, the AMOC anomaly is used as a precursor of North Atlantic sea-surface temperature anomalies (SSTAs). The results show that the AMOC leads a dipolar SSTA with maximum correlations between 2 and 5 months. The physical mechanism explaining the link between AMOC and SSTA is described as a seesaw mechanism where a strong AMOC anomaly increases the amount of heat advected north of 26 ∘ N as well as the SSTA, and decreases the heat content and the SSTA south of this section. In order to further understand the origins of this SSTA dipole, the respective contributions of the heat advected by the AMOC versus the Ekman transport and air–sea fluxes have been assessed. We found that at a 5-month lag, the Ekman component mainly contributes to the southern part of the dipole and cumulative air–sea fluxes only explain a small fraction of the SSTA variability. Given that the southern part of the SSTA dipole encompasses the main development region for Atlantic hurricanes, our results therefore suggest the potential for AMOC observations from 26 ∘ N to be used to complement existing seasonal hurricane forecasts in the Atlantic

Drivers of exceptionally cold North Atlantic Ocean temperatures and their link to the 2015 European heat wave

The North Atlantic and Europe experienced two extreme climate events in 2015: exceptionally cold ocean surface temperatures and a summer heat wave ranked in the top ten over the past 65 years. Here, we show that the cold ocean temperatures were the most extreme in the modern record over much of the mid-high latitude North-East Atlantic. Further, by considering surface heat loss, ocean heat content and wind driven upwelling we explain for the first time the genesis of this cold ocean anomaly. We find that it is primarily due to extreme ocean heat loss driven by atmospheric circulation changes in the preceding two winters combined with the re-emergence of cold ocean water masses. Furthermore, we reveal that a similar cold Atlantic anomaly was also present prior to the most extreme European heat waves since the 1980s indicating that it is a common factor in the development of these events. For the specific case of 2015, we show that the ocean anomaly is linked to a stationary position of the Jet Stream that favours the development of high surface temperatures over Central Europe during the heat wave. Our study calls for an urgent assessment of the impact of ocean drivers on major European summer temperature extremes in order to provide better advance warning measures of these high societal impact events

Distributional Patterns of Polychaetes Across the West Antarctic Based on DNA Barcoding and Particle Tracking Analyses

Recent genetic investigations have uncovered a high proportion of cryptic species within Antarctic polychaetes. It is likely that these evolved in isolation during periods of glaciation, and it is possible that cryptic populations would have remained geographically restricted from one another occupying different regions of Antarctica. By analysing the distributions of nine morphospecies, (six of which contained potential cryptic species), we find evidence for widespread distributions within the West Antarctic. Around 60% of the cryptic species exhibited sympatric distributions, and at least one cryptic clade was found to be widespread. Additional DNA barcodes from GenBank and morphological records extended the observed range of three species studied here, and indicate potential circum-Antarctic traits. Particle tracking analyses were used to model theoretical dispersal ranges of pelagic larvae. Data from these models suggest that the observed species distributions inferred from genetic similarity could have been established and maintained through the regional oceanographic currents, including the Antarctic Circumpolar Current (ACC) and its coastal counter current. Improved understanding of the distribution of Antarctic fauna is essential for predicting the impacts of environmental change and determining management strategies for the region.Copyright © 2017 Brasier, Harle, Wiklund, Jeffreys, Linse, Ruhl and Glover. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms

Valorization of co-products generated by Argan oil extraction process: Application to biodiesel production.

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Caractérisation d'un bioréacteur pour la culture de <em>Saccharomyces cerevisiae</em> soumis à des champs électro-magnétiques en environnements anéchoïque et réverbérant

National audienceCe travail caractérise un dispositif expérimental conçu pour étudier les effets des ondes électro magnétiques sur des cellules eucaryotes (Saccharomyces cerevisiae) cultivées en bioréacteur tout en permettant les régulations de température, de pH, de pO2, d’agitation et d’aération influençant la croissance des cellules. Les simulations numériques réalisées montrent que l’atténuation des ondes électromagnétiques au sein du milieu de culture est importante et que les modifications des propriétés diélectriques du milieu liées à la fréquence des ondes incidentes et aux variations de composition du milieu au cours de la culture peuvent avoir une influence sur le niveau d’exposition des cellules aux champs électromagnétiques. Les essais réalisés en environnements anéchoïque et réverbérant ne mettent pas en évidence d’effet sur le taux de croissance et les rendements de production des différents métabolites de la levure soumise aux champs électromagnétiques

Saccharomyces cerevisiae culture in a reverberant environment

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Caractérisation d'un bioréacteur pour la culture de Saccharomyces cerevisiae soumis à des champs électromagnétiques en environnements anéchoïqu et réverbérant.

International audienc

The Antilles Current and wind-driven gyre circulation at 26oN

The Antilles Current is a narrow, northward flowing boundary current in the western Atlantic just east of the Bahamas. Its role in the larger scale circulation has been debated: alternately thought to be part of the western boundary closure of the gyre circulation or the northward flowing limb of the meridional overturning circulation (MOC). From 19 years of moored current meter observations (1987--1991, 2004--2018), we define the strength of the Antilles Current by the net transport between the Bahamas and 76.5°W (spanning about 45 km zonally) and in the thermocline (0–1000 m). We find a mean northward transport of 3.5 Sv, substantial interannual variability, and no discernable trend since 1987. The interannual variability of the AC transport is independent of the variability of the Florida Current (the Gulf Stream through the Florida Straits). Instead, the Antilles Current contributes to the interannual variability of the MOC at 26°N, while the trend in the strength of the gyre circulation (defined as the transbasin thermocline transport minus the AC) is responsible for the trend in the MOC. In particular, the 2009/10 slowdown of the MOC resulted from a weaker northward AC transport, rather than an intensified gyre transport. Using the recent 14 years of in situ transport records, we compare the interannual variability of the gyre circulation to that of wind stress curl forcing via a Sverdrup transport calculation, identifying a potential role for wind stress curl (WSC) forcing at 26°N with a ~2 year lag until 2016. From 2016, the predicted gyre circulation using WSC diverges from the measured gyre strength

High-frequency, high-intensity electromagnetic field effects on Saccharomyces cerevisiae conversion yields and growth rates in a reverberant environment

2. International Conference on Alternative Fuels and Energy (ICAFE) ; Daegu (Corée (Populaire)) - (2017-10-23 - 2017-10-25) / ConférenceStudies of the effects of electromagnetic waves on Saccharomyces cerevisiae emphasize the need to develop instrumented experimental systems ensuring a characterization of the exposition level to enable unambiguous assessment of their potential effects on living organisms. A bioreactor constituted with two separate compartments has been designed. The main element (75% of total volume) supporting all measurement and control systems (temperature, pH, agitation, and aeration) is placed outside the exposure room whereas the secondary element is exposed to irradiation. Measurements of the medium dielectric properties allow the determination of the electromagnetic field at any point inside the irradiated part of the reactor and are consistent with numerical simulations. In these conditions, the growth rate of Saccharomyces cerevisiae and the ethanol yield in aerobic conditions are not significantly modified when submitted to an electromagnetic field of 900 and 2400 MHz with an average exposition of 6.11 V.m−1 and 3.44 V.m−1 respectively

Saccharomyces cerevisiae culture in a reverberant electromagnetic environment

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