IMBE News   Jeudi 16 mars 2017  -




Les présidentielles et la science : nous interpellons les candidats
Tous les candidats à l’élection présidentielle qui s’approche déroulent à l’heure présente leurs programmes et leurs propositions.

Néanmoins, une fois encore, comme dans toutes les élections dont j’ai souvenir, les questions de science et de technologie restent quasi-absentes des débats, comme si jamais les candidats ne s’étaient avisés qu’elles puissent nous concerner, comme si elles n’étaient destinées qu’aux spécialistes et qu’il leur appartiendrait d’y répondre, ou comme si elles n’intéressaient pas nos concitoyens.


La course d’obstacles des « publis »

La rédaction d’un article scientifique constitue l’aboutissement naturel de tous les travaux de recherche.
Les contributions soumises aux revues primaires passent par une étape dite de relecture et révision par les pairs ; c’est-à-dire que d’autres chercheurs du domaine, sous une garantie d’anonymat et en l’absence de conflit d’intérêt, se portent garants que les travaux proposés à la publication respectent les standards de qualité attendus par la communauté scientifique



La découverte fondamentale de chercheurs français qui ouvre la porte à un traitement définitif contre le sida
Voilà plus de trente ans que les scientifiques cherchent un moyen de venir à bout du Sida. Si les trithérapies ont réussi à contenir l'action du VIH, il est pour le moment impossible d'éradiquer totalement le virus.
Mais les choses pourraient bien changer dans les années à venir grâce à une importante découverte réalisée par des chercheurs français.

Article in Nature
CD32a is a marker of a CD4 T-cell HIV reservoir harbouring replication-competent proviruses - Benjamin Descours, Gaël Petitjean, José-Luis López-Zaragoza, Timothée Bruel, Raoul Raffel, Christina Psomas, Jacques Reynes, Christine Lacabaratz, Yves Levy, Olivier Schwartz, Jean Daniel Lelievre & Monsef Benkirane


Happy 50th, Endangered Species. And Many More?
Fifty years ago, the first species gained official federal protection as endangered. Those protections are now in danger.
Fifty years ago, the first species to gain federal protection as endangered were listed in the Federal Register. Now, despite much progress in the decades since, they may be in more trouble than ever before.


Le monde selon Monsanto
Roundup : que peut l’initiative citoyenne « Ban glyphosate » ?
Depuis plusieurs années, l’ONG de protection de l’environnement Greenpeace réclame l’interdiction du glyphosate, principal ingrédient du désherbant Roundup commercialisé par la firme américaine Monsanto.
Dénoncé comme néfaste pour l’environnement, il est aussi accusé d’être une menace pour la santé. Des études l’ont en effet identifié comme perturbateur endocrinien.



Le pire est encore à venir ...
In support of international students
Harvard offers array of services, resources so they can navigate latest travel ban, ensure safe return
As President Trump last week issued a new executive order preventing citizens from six Muslim-majority countries from entering the United States for 90 days, Harvard continued to ramp up efforts to support international students and scholars in understanding and coping with the policy shift.


James Mattis Admits Climate Change Is a Threat
That puts him at odds with many high-ranking officials in the Trump administration.
In an unpublished testimony to the Armed Services Committee, Secretary of Defense James Mattis called climate change a security threat for which United States military leaders need to prepare, ProPublica reports. “Climate change is impacting stability in areas of the world where our troops are operating today,” Mattis wrote to the committee after his confirmation hearing. This marks the first time Mattis has said that climate change is a real and current threat as a member of the Trump administration—an assertion that puts him at odds with many of his new colleagues.







In Sciences Eaux & Territoires (IRSTEA)
Du changement climatique au changement des pratiques agricoles : une démarche prospective dans un village indien


In Journal of Quaternary Science
A tree-ring chronology and paleoclimate record for the Younger Dryas–Early Holocene transition from northeastern North America
Carol Griggs, Dorothy Peteet, Bernd Kromer, Todd Grote, John Southon - Journal of Quaternary Science 2017
Spruce and tamarack logs dating from the Younger Dryas and Early Holocene (YD–EH;
12.9–11.3k cal a BP) were found at Bell Creek in the Lake Ontario lowlands of the Great Lakes region, North America. A 211-year tree-ring chronology dates to 11 755–11 545 cal a BP, across the YD–EH transition. A 23-year period of higher year-to-year ring-width variability dates to around 11 650 cal a BP, infers strong regional climatic perturbations and may represent the end of the YD. Tamarack and spruce were dominant species throughout the YD–EH interval at the site, indicating that boreal conditions persisted into the EH, in contrast to geographical regions immediately south and east of the lowlands, but consistent with the Great Lakes interior lowlands.


In Earth Surface Processes and Landforms
Reintroduced large wood modifies fine sediment transport and storage in a lowland river channel
Chris Parker, Alexander J. Henshaw, Gemma L. Harvey, Carl D. Sayer - Earth Surface Processes and Landforms 2017
This paper explores changes in suspended sediment transport and fine sediment storage at the reach and patch scale associated with the reintroduction of partial large wood (LW) jams in an artificially over-widened lowland river.


In Irrigation and Drainage
Impacts of man-Induced Changes in Land use and Climate Change on Living in Coastal and Deltaic Areas
Bart Schultz - Irrigation and Drainage 2017
Sea level rise due to climate change is presented as one of our biggest problems. The reality is quite different and generally insufficiently taken into account in decision-making. 80–90% of the population growth takes place in urban areas that are located in coastal and deltaic regions. In the majority of these areas there is land subsidence with a much larger impact than sea level rise. Commonly, inadequate measures are taken to reduce the risk of flooding.






Animal poisoners in native forests
Oribatid mite uses hydrogen cyanide for defense
The common oribatid mite species Oribatula tibialis is an extremely clever poisoner, as an interdisciplinary team of researchers has found. The mite uses hydrogen cyanide to defend itself against predators. This is something of a sensation, because this toxin is not generally present in the arsenal of the 80,000 known species of arachnids

Adrian Brückner, Günther Raspotnig, Katja Wehner, Reinhard Meusinger, Roy A. Norton, Michael Heethoff. Storage and release of hydrogen cyanide in a chelicerate ( Oribatula tibialis ). Proceedings of the National Academy of Sciences, 2017


Deep-sea coral evidence for lower Southern Ocean surface nitrate concentrations during the last ice age
Xingchen Tony Wang, Daniel M. Sigman, Maria G. Prokopenko, Jess F. Adkins, Laura F. Robinson, Sophia K. Hines, Junyi Chai, Anja S. Studer, Alfredo Martínez-García, Tianyu Chen, and Gerald H. Haug
The concentration of atmospheric carbon dioxide (pCO2) varies by 80–100 ppm on glacial–interglacial timescales, with lower pCO2 during the ice ages. In the modern Southern Ocean, the surface nutrients are not fully consumed by phytoplankton, resulting in leakage of deeply sequestered CO2 to the atmosphere.


Enhanced groundwater recharge rates and altered recharge sensitivity to climate variability through subsurface heterogeneity
Andreas Hartmann, Tom Gleeson, Yoshihide Wada, and Thorsten Wagener
Understanding the implications of climate changes on hydrology is crucial for water resources management. Widely used global hydrological models generally assume simple homogeneous subsurface representations to translate climate signals into hydrological variables. We study groundwater recharge in the carbonate rock regions of Europe, Northern Africa, and the Middle East, which are known to exhibit strong subsurface heterogeneity.


Human-started wildfires expand the fire niche across the United States  
Jennifer K. Balch, Bethany A. Bradley, John T. Abatzoglou, R. Chelsea Nagy, Emily J. Fusco, and Adam L. Mahood
Fighting wildfires in the United States costs billions of dollars annually. Public dialog and ongoing research have focused on increasing wildfire risk because of climate warming, overlooking the direct role that people play in igniting wildfires and increasing fire activity.


Microbial community assembly and evolution in subseafloor sediment
Piotr Starnawski, Thomas Bataillon, Thijs J. G. Ettema, Lara M. Jochum, Lars Schreiber, Xihan Chen, Mark A. Lever, Martin F. Polz, Bo B. Jørgensen, Andreas Schramm, and Kasper U. Kjeldsen
Our study shows that deep subseafloor sediments are populated by descendants of rare members of surface sediment microbial communities that become predominant during burial over thousands of years. We provide estimates of mutation rates and strength of purifying selection in a set of taxonomically diverse microbial populations in marine sediments and show that their genetic diversification is minimal during burial.


Intensified agriculture favors evolved resistance to biological control

Federico Tomasetto, Jason M. Tylianakis, Marco Reale, Steve Wratten, and Stephen L. Goldson
The need for agricultural production to meet the food demands of a growing human population will require sustainable and acceptable pest management, such as biological control, across 11% (1.5 billion ha) of the globe’s land surface. However, the long-term viability of this ecosystem service can be threatened by the expansion and simplification of agricultural systems, which may facilitate the evolution of resistance by pests to their control agents.


Pacific North American circulation pattern links external forcing and North American hydroclimatic change over the past millennium

Zhongfang Liu, Yanlin Tang, Zhimin Jian, Christopher J. Poulsen, Jeffrey M. Welker, and Gabriel J. Bowen
We have developed a new reconstruction of changes in the wintertime atmospheric circulation over North America based on data distributed across the region. The record spans almost 1,000 years and shows how variation in ocean temperatures, solar energy, volcanic eruptions, and greenhouse gases has affected circulation over this period.


Flowering phenology shifts in response to biodiversity loss

Amelia A. Wolf, Erika S. Zavaleta, and Paul C. Selmants
Advanced spring flowering has been described as a fingerprint of climate change—a public, visible display of the detrimental effects of global warming. However, warming experiments fail to account for the full magnitude of observed changes in phenology, suggesting that other factors may play important roles.


In Nature Communications
Flies and bees act like plant cultivators
Pollinator insects accelerate plant evolution, but a plant changes in different ways depending on the pollinator. After only nine generations, the same plant is larger and more fragrant if pollinated by bumblebees rather than flies, as a study reveals

Daniel D. L. Gervasi, Florian P Schiestl. Real-time divergent evolution in plants driven by pollinators. Nature Communications, 2017


In Frontiers in Earth Science
Did humans create the Sahara desert?
New research challenges the idea that changes in the Earth's orbit triggered Sahara desertification
New research investigating the transition of the Sahara from a lush, green landscape 10,000 years ago to the arid conditions found today, suggests that humans may have played an active role in its desertification.
David K. Wright. Humans as Agents in the Termination of the African Humid Period. Frontiers in Earth Science, 2017


In Nature Geoscience
Ice age thermostat prevented extreme climate cooling
During the ice ages, an unidentified regulatory mechanism prevented atmospheric carbon dioxide concentrations from falling below a level that could have led to runaway cooling, reports a team of researchers. The study suggests the mechanism may have involved the biosphere, as plants and plankton struggled to grow under very low carbon dioxide levels.

E. D. Galbraith, S. Eggleston. A lower limit to atmospheric CO2 concentrations over the past 800,000 years. Nature Geoscience, 2017


In Journal of Urban Ecology
At mealtime, honey bees prefer country blossoms to city blooms
Urban beekeeping could suffer as a result, study authors say
Hungry honey bees appear to favor flowers in agricultural areas over those in neighboring urban areas. The discovery has implications for urban beekeepers and challenges assumptions that farmland and honey bees are incompatible, said authors of a new study.

Douglas B. Sponsler, Emma G. Matcham, Chia-Hua Lin, Jessie L. Lanterman, Reed M. Johnson. Spatial and taxonomic patterns of honey bee foraging: A choice test between urban and agricultural landscapes. Journal of Urban Ecology, 2017


In PLOS Biology
World's oldest plant-like fossils show multicellular life appeared earlier than thought
Scientists have found fossils of 1.6 billion-year-old probable red algae. The spectacular finds indicate that advanced multicellular life evolved much earlier than previously thought.

Stefan Bengtson, Therese Sallstedt, Veneta Belivanova, Martin Whitehouse. Three-dimensional preservation of cellular and subcellular structures suggests 1.6 billion-year-old crown-group red algae. PLOS Biology, 2017


In Earth's Future
Increase in extreme sea levels could endanger European coastal communities
Massive coastal flooding in northern Europe that now occurs once every century could happen every year if greenhouse gas emissions continue to rise, according to a new study.

Michalis I. Vousdoukas, Lorenzo Mentaschi, Evangelos Voukouvalas, Martin Verlaan, Luc Feyen. Extreme sea levels on the rise along Europe's coasts. Earth's Future, 2017


In Marine and Freshwater Research
Thirsty mangroves cause unprecedented dieback
A scientist has discovered why there was an unprecedented dieback of mangroves in the Gulf of Carpentaria in early 2016 -- the plants died of thirst

Norman C. Duke, John M. Kovacs, Anthony D. Griffiths, Luke Preece, Duncan J. E. Hill, Penny van Oosterzee, Jock Mackenzie, Hailey S. Morning, Damien Burrows. Large-scale dieback of mangroves in Australia. Marine and Freshwater Research, 2017


In Molecular Ecology
Microbes measure ecological restoration success
The success of ecological restoration projects around the world could be boosted using a potential new tool that monitors soil microbes, say scientists

Nicholas J.C. Gellie, Jacob G. Mills, Martin F. Breed, Andrew J. Lowe. Revegetation rewilds the soil bacterial microbiome of an old field. Molecular Ecology, 2017




Un peu de poèsie ...
« Ce n’est pas un conte de fées, les arbres parlent » : la découverte d’une professeur de Colombie-Britannique
Si on vous disait que les arbres peuvent se parler entre eux, échanger des informations et communiquer, pourriez-vous le croire ? On pourrait se dire que cette réalité est impossible et relève d’un conte de fées pour enfants. Récemment, la science a néanmoins prouvé que ce « conte de fées » était un fait.
Suzanne Simard, professeur de sciences forestières à l’université de Colombie-Britannique (UBC), a prouvé que les arbres pouvaient communiquer avec leurs pairs à travers plus de 80 expérimentations scientifiques. Les résultats de ces expériences ont eu un fort impact après leur publication.

Conférence :





Dans la radio de la Calédonie ...
Le docteur Catala et la création de l’Institut français d’Océanie (14 Mars 2017)
Interview de
J-Y. Meunier (IRD)
Il y a, un peu plus de 70 ans, était créé par le docteur René Catala, l’Institut français d’Océanie (IFO) qui est à l’origine de l’actuelle IRD. Nous recevons, pour nous en parler, M. Jean-Yves Meunier, qui vient de publier, dans le bulletin de la SEHNC, un article justement consacré à cet événement.


Agriculture bio : attention au fétichisme du label
Beaucoup d’observateurs parlent aujourd’hui d’un « changement d’échelle » de l’agriculture biologique en France.
Selon l’Agence bio, les ventes de produits dans ce secteur ont doublé en six ans, pour atteindre sept milliards d’euros à la fin de l’année 2016. Pour certains produits, la part de marché commence à être significative : 20 % pour les œufs et 12 % pour le lait, par exemple.


Les araignées mangent plus de « viande » que l’humanité

... Dans leur article, Martin Nyffeler et Klaus Birkhofer commencent par le commencement, à savoir évaluer la biomasse totale de la communauté des Araneae à la surface du globe. En compilant 65 estimations tirées de la littérature scientifique et réalisées dans sept biomes, sept grands types d’écosystèmes – forêts tropicales, forêts tempérées et boréales, prairies tropicales et savanes, prairies tempérées et garrigues méditerranéennes, terres agricoles, déserts, toundras arctiques –, ils sont parvenus à la conclusion que le peuple des araignées pesait 25 millions de tonnes. Un chiffre à comparer avec les 287 millions de tonnes de la population adulte humaine en 2005.

Spiders eat astronomical numbers of insects


Le taux de réussite au bac a battu un nouveau record en 2016
Stable dans les voies générale et technologique, il a progressé de deux points dans la voie professionnelle.