CO2 addition to increase biomass production and control microalgae species in high rate algal ponds treating wastewater

Challenges regarding microalgal cultivation need to be solved in order to enhance microalgae potential as a feedstock for biofuel, bioenergy, and bioproducts. The optimization of the operating strategy in high rate algal ponds treating wastewater still requires research on microalgal ecosystem response to variations in nutrients availability. For this reason, the aim of this study was to determine the effect of CO2 addition on microalgal population diversity and wastewater treatment performance. To this end, batch and continuous experiments were carried out in an experimental plant constituted by four high rate algal ponds (500 L each) treating urban wastewater with and without pH regulation. As expected, CO2 addition induced a significant increase in biomass concentration (between 66 and 100%). Moreover, a positive effect on microalgal biomass concentration was observed, reducing the effect of the variation in influent wastewater characteristics. Concerning the microalgal populations, the variation of inorganic carbon availability induced a shift in the dominant microalgae species. In spite of this, no variations were observed in terms of wastewater treatment efficiency. Taking together, this study highlighted the positive effect of CO2 addition to increase biomass production and control microalgae species in high rate algal ponds treating wastewater.Peer ReviewedPostprint (author's final draft

Influence of intensive agriculture and geological heterogeneity on the recharge of an arid aquifer system (Saq–Ram, Arabian Peninsula) inferred from GRACE data

This study assesses the detailed water budget of the Saq–Ram Aquifer System (520 000 km2) over the 2002–2019 period using satellite gravity data from the Gravity Recovery And Climate Experiment (GRACE). The three existing GRACE solutions were tested for their local compatibility to compute groundwater storage (GWS) variations in combination with the three soil moisture datasets available from the land surface models (LSMs) of the Global Land Data Assimilation System (GLDAS). Accounting for groundwater pumping, artificial recharge, and natural discharge uniformly distributed over the Saq–Ram domain, the GRACE-derived mass balance calculation for water yields a long-term estimate of the domain-averaged natural recharge of (2.4±1.4) mm yr−1, corresponding to (4.4±2.6) % of the annual average rainfall (AAR). Beyond the regional-scale approach proposed here, spatial heterogeneities regarding the groundwater recharge were identified. The first source of heterogeneity is of anthropogenic origin: chiefly induced by irrigation excess over irrigated surfaces (about 1 % of the domain), artificial recharge corresponds to half of the total recharge of the aquifer. The second source of recharge heterogeneity identified here is natural: volcanic lava deposits (called harrats on the Arabian Peninsula) which cover 8 % of the Saq–Ram aquifer domain but contribute to more than 50 % of the natural recharge. Hence, in addition to this application on the Arabian Peninsula, this study strongly indicates a major control of geological context on arid aquifer recharge, which has been poorly discussed hitherto. Due to large lag times of the diffuse recharge mechanism, the annual analysis using this GRACE–GLDAS approach in arid domains should be limited to areas where focused recharge is the main mechanism, while long-term analysis is valid regardless of the recharge mechanism. Moreover, it appears that about 15 years of GRACE records are required to obtain a relevant long-term recharge estimate.</p

Quantifying the modern recharge of the "fossil" Sahara aquifers

The North-Western Sahara Aquifer System (NWSAS), one of the world's largest groundwater systems, shows an overall piezometric decline associated with increasing withdrawals. Estimating the recharge rate in such a semiarid system is challenging but crucial for sustainable water development. In this paper, the recharge of the NWSAS is estimated using a regional water budget based on GRACE terrestrial water storage monthly records, soil moisture from the GLDAS (a land data system that assimilates hydrological information), and groundwater pumping rates. A cumulated natural recharge rate of 1.40 +/- 0.90 km(3) yr(-1) is estimated for the two main aquifers. Our results suggest a renewal rate of about 40% which partly contradicts the premise that recharge in this area should be very low or even null. Aquifer depletion inferred from our analysis is consistent with observed piezometric head decline in the two main aquifers in the region. Annual recharge variations were also estimated and vary between 0 and 4.40 km(3) yr(-1) for the period 2003-2010. These values correspond to a recharge between 0 and 6.75 mm yr(-1) on the 650,000 km(2) of outcropping areas of the aquifers, which is consistent with the expected weak and sporadic recharge in this semiarid environment. These variations are also in line with annual rainfall variation with a lag time of about 1 year

11th Applied isotope geochemistery conference AIG-11

36Cl measurements in groundwaters of the deep confined aquifer of the Lake Chad Basin (LCB) were performed in order to constrain groundwater geochemical ages and residence times. Twenty-seven wells were sampled in Nigeria, Niger and Chad in the southern parts of the large (700 000 km2) multilayered aquifer of the LCB. 36Cl/Cl values range between 11±1.10-15 to 148±8.10-15 at/at. The highest ratios are observed near the recharge zone of the Nigerian part of the Continental Terminal aquifer, while the lowest ones are found in wells located near the southern fringe of the present-day lake Chad. Chloride concentrations are low (below 100 mg/l) and not correlated to the 36Cl/Cl values, indicating negligible dissolution of evaporites in most samples. Reliable 36Cl ages can be calculated along the different flow paths investigated, suggesting residence times of the deep groundwaters larger than 300 000 years. These results are consistent with new AMS-14C data below the detection limit but are in contradiction with previous 14C data obtained in the area

Apport des datations U/Th de spéléothèmes à la connaissance de l’incision du réseau hydrographique de l’Est du Bassin parisien

Dans l’Est du Bassin parisien, la karstification s’exprime selon deux modes essentiels, soit au contact d’une couverture argilo-sableuse sur les plateaux calcaires, soit au contact d’une nappe alluviale dans les fonds de vallée. Dans tous les cas, l’évolution de ces karsts suit l’incision des vallées. On présente ici trois sites karstiques majeurs (Pierre-la-Treiche, Trampot et le Barrois), inféodés à trois grandes vallées de l’Est du Bassin parisien (la Moselle, la Meuse et la Marne) recoupant trois grandes masses carbonatées (Bajocien, Oxfordien, Tithonien). Dans ces karsts, 84 datations ont été entreprises par la méthode U/Th soit en alpha, soit en TIMS. La synthèse de ces dates confirme l’apport que constitue le karst dans les reconstitutions paléoenvironnementales en particulier dans le domaine de l’incision du réseau hydrographique, du recul des couvertures non carbonatées et des reconstitutions paléoclimatiques.In the eastern part of the Paris Basin, karstification occurs, essentially in two modes, one at the contact of a sandy-clayey cover on limestone plateaus, the other beneath alluvium in the floors of valleys. In every case, evolution of the karsts follows incision of the valleys. In this paper, three major karstic systems are presented (Pierre-la-Treiche, Trampot and the Barrois), associated with three large valleys (the Moselle, the Meuse and the Marne), cutting three large limestone masses (Bajocien, Oxfordien, Tithonien). In these karsts, 84 dates were obtained using the U/Th method (alpha, TIMS). These dates confirm the contribution of the karst to palaeoenvironmental reconstruction in the fields of river system incision, retreat of the non-carbonate cover and palaeoclimatic reconstruction.Im Osten des Pariser Beckens  erscheint die Verkarstung in zwei wesentlichen Formen – in Kontakt mit einer lehmig-sandigen Decke auf den Kalkplateaus oder in Kontakt mit einer alluvialen Schicht in den Talgründen. In allen Fällen folgt die Entwicklung dieser Karste dem Einschneiden der Täler. Hier werden drei größere Karstbereiche vorgestellt (Pierre-la-Treiche, Trampot und das Barrois), die drei grossen Tälern (Mosel, Maas und Marne) zugehören und drei grosse Kalkmassive (Bajocien, Oxfordien, Tithonien) anschneiden. In diesen Karstgebieten wurden 84 Datierungen nach der Methode U/Th in alpha oder in TIMS vorgenommen. Die Synthese dieser Daten bestätigt den Beitrag, den der Karst für die paläogeographische Rekonstruierung liefert, insbesondere im Bereich des Einschneidens des hydrographischen Netzes, des Rückweichens der nichtkalkigen Deckschichten und paläoklimatischer Rekonstruktionen

Apport des datations U/Th de spéléothèmes à la connaissance de l’incision du réseau hydrographique de l’Est du Bassin parisien

Dans l’Est du Bassin parisien, la karstification s’exprime selon deux modes essentiels, soit au contact d’une couverture argilo-sableuse sur les plateaux calcaires, soit au contact d’une nappe alluviale dans les fonds de vallée. Dans tous les cas, l’évolution de ces karsts suit l’incision des vallées. On présente ici trois sites karstiques majeurs (Pierre-la-Treiche, Trampot et le Barrois), inféodés à trois grandes vallées de l’Est du Bassin parisien (la Moselle, la Meuse et la Marne) recoupant trois grandes masses carbonatées (Bajocien, Oxfordien, Tithonien). Dans ces karsts, 84 datations ont été entreprises par la méthode U/Th soit en alpha, soit en TIMS. La synthèse de ces dates confirme l’apport que constitue le karst dans les reconstitutions paléoenvironnementales en particulier dans le domaine de l’incision du réseau hydrographique, du recul des couvertures non carbonatées et des reconstitutions paléoclimatiques.In the eastern part of the Paris Basin, karstification occurs, essentially in two modes, one at the contact of a sandy-clayey cover on limestone plateaus, the other beneath alluvium in the floors of valleys. In every case, evolution of the karsts follows incision of the valleys. In this paper, three major karstic systems are presented (Pierre-la-Treiche, Trampot and the Barrois), associated with three large valleys (the Moselle, the Meuse and the Marne), cutting three large limestone masses (Bajocien, Oxfordien, Tithonien). In these karsts, 84 dates were obtained using the U/Th method (alpha, TIMS). These dates confirm the contribution of the karst to palaeoenvironmental reconstruction in the fields of river system incision, retreat of the non-carbonate cover and palaeoclimatic reconstruction.Im Osten des Pariser Beckens  erscheint die Verkarstung in zwei wesentlichen Formen – in Kontakt mit einer lehmig-sandigen Decke auf den Kalkplateaus oder in Kontakt mit einer alluvialen Schicht in den Talgründen. In allen Fällen folgt die Entwicklung dieser Karste dem Einschneiden der Täler. Hier werden drei größere Karstbereiche vorgestellt (Pierre-la-Treiche, Trampot und das Barrois), die drei grossen Tälern (Mosel, Maas und Marne) zugehören und drei grosse Kalkmassive (Bajocien, Oxfordien, Tithonien) anschneiden. In diesen Karstgebieten wurden 84 Datierungen nach der Methode U/Th in alpha oder in TIMS vorgenommen. Die Synthese dieser Daten bestätigt den Beitrag, den der Karst für die paläogeographische Rekonstruierung liefert, insbesondere im Bereich des Einschneidens des hydrographischen Netzes, des Rückweichens der nichtkalkigen Deckschichten und paläoklimatischer Rekonstruktionen

Repurposing of Drugs as Novel Influenza Inhibitors From Clinical Gene Expression Infection Signatures

Influenza virus infections remain a major and recurrent public health burden. The intrinsic ever-evolving nature of this virus, the suboptimal efficacy of current influenza inactivated vaccines, as well as the emergence of resistance against a limited antiviral arsenal, highlight the critical need for novel therapeutic approaches. In this context, the aim of this study was to develop and validate an innovative strategy for drug repurposing as host-targeted inhibitors of influenza viruses and the rapid evaluation of the most promising candidates in Phase II clinical trials. We exploited in vivo global transcriptomic signatures of infection directly obtained from a patient cohort to determine a shortlist of already marketed drugs with newly identified, host-targeted inhibitory properties against influenza virus. The antiviral potential of selected repurposing candidates was further evaluated in vitro, in vivo, and ex vivo. Our strategy allowed the selection of a shortlist of 35 high potential candidates out of a rationalized computational screening of 1,309 FDA-approved bioactive molecules, 31 of which were validated for their significant in vitro antiviral activity. Our in vivo and ex vivo results highlight diltiazem, a calcium channel blocker currently used in the treatment of hypertension, as a promising option for the treatment of influenza infections. Additionally, transcriptomic signature analysis further revealed the so far undescribed capacity of diltiazem to modulate the expression of specific genes related to the host antiviral response and cholesterol metabolism. Finally, combination treatment with diltiazem and virus-targeted oseltamivir neuraminidase inhibitor further increased antiviral efficacy, prompting rapid authorization for the initiation of a Phase II clinical trial. This original, host-targeted, drug repurposing strategy constitutes an effective and highly reactive process for the rapid identification of novel anti-infectious drugs, with potential major implications for the management of antimicrobial resistance and the rapid response to future epidemic or pandemic (re)emerging diseases for which we are still disarmed

Ice-sheet collapse and sea-level rise at the Bølling warming 14,600 years ago

Past sea-level records provide invaluable information about the response of ice sheets to climate forcing. Some such records suggest that the last deglaciation was punctuated by a dramatic period of sea-level rise, of about 20 metres, in less than 500 years. Controversy about the amplitude and timing of this meltwater pulse (MWP-1A) has, however, led to uncertainty about the source of the melt water and its temporal and causal relationships with the abrupt climate changes of the deglaciation. Here we show that MWP-1A started no earlier than 14,650 years ago and ended before 14,310 years ago, making it coeval with the Bolling warming. Our results, based on corals drilled offshore from Tahiti during Integrated Ocean Drilling Project Expedition 310, reveal that the increase in sea level at Tahiti was between 12 and 22 metres, with a most probable value between 14 and 18 metres, establishing a significant meltwater contribution from the Southern Hemisphere. This implies that the rate of eustatic sea-level rise exceeded 40 millimetres per year during MWP-1A