Institut Écologie et Environnement

The eastern Mediterranean region witnessed changes in human culture of the highest importance between ~9000 and ~2500 cal. BP (7000—500 BC) and over the same time period was affected by very significant shifts in climate. Stable isotope data from lake and deep-sea sediment cores and from cave speleothems show an overall trend from a wetter to a drier climate during the mid Holocene. Superimposed on this trend were multicentennial oscillations in climate, with notable arid phases occurring around 5300—5000 BP, 4500—3900 BP, and 3100—2800 BP (all ages are expressed in calibrated/ calendar years). These phases coincide with major archaeological transitions across the eastern Mediterranean region (Chalcolithic to early Bronze Age, EBA to MBA, and LBA to Iron Age) implying that environmental stress or opportunity may have acted as a pacemaker for cultural change and re-organisation. We use 14 C and δ 13 C analysis of archaeobotanical samples from two protohistoric sites in Syria to illustrate the linkage between water availability, climate and cultural change during the third and second millennia BC. Specific societal responses to environmental change were not predictable in advance, but resulted instead from contingent processes involving antecedent conditions, human choice and adaptive strategies. Pollen analysis highlights how changes in climate were coupled to increasing human impacts to transform the region’s landscapes. Initial human-induced land-cover transformation commonly took place during Bronze Age times, sometimes coinciding with phases of drier climate, although the pattern and precise timing varied between sites. Changes in climate between the early and late Holocene thus helped to transform eastern Mediterranean landscape ecologies and human cultures, but in complex, non-deterministic ways.

Faced with sea level rise and the intensification of extreme events, human populations living on the coasts are developing responses to address local situations. A synthesis of the literature on responses to coastal adaptation allows us to highlight different adaptation strategies. Here, we analyze these strategies according to the complexity of their implementation, both institutionally and technically. First, we distinguish two opposing paradigms – fighting against rising sea levels or adapting to new climatic conditions; and second, we observe the level of integrated management of the strategies. This typology allows a distinction between four archetypes with the most commonly associated governance modalities for each. We then underline the need for hybrid approaches and adaptation trajectories over time to take into account local socio-cultural, geographical, and climatic conditions as well as to integrate stakeholders in the design and implementation of responses. We show that dynamic and participatory policies can foster collective learning processes and enable the evolution of social values and behaviors. Finally, adaptation policies rely on knowledge and participatory engagement, multi-scalar governance, policy monitoring, and territorial solidarity. These conditions are especially relevant for densely populated areas that will be confronted with sea level rise, thus for coastal cities in particular.

Osedax worms are whale-fall specialists that infiltrate whale bones with their root tissues. These are filled with endosymbiotic bacteria hypothesized to provide their hosts with nutrition by extracting organic compounds from the whale bones. We investigated the diversity and distribution of symbiotic bacteria in Osedax mucofloris from shallow-water whale-falls in the North Atlantic using comparative 16S rRNA sequence analysis and fluorescence in situ hybridization (FISH). We observed a higher diversity of endosymbionts than previously described from other Osedax species. Endosymbiont sequences fell into eight phylogenetically distinct clusters (with 91.4-98.9% similarity between clusters), and considerable microdiversity within clusters (99.5-99.7% similarity) was observed. Statistical tests revealed a highly significant effect of the host individual on endosymbiont diversity and distribution, with 68% of the variability between clusters and 40% of the variability within clusters explained by this effect. FISH analyses showed that most host individuals were dominated by endosymbionts from a single cluster, with endosymbionts from less abundant clusters generally confined to peripheral root tissues. The observed diversity and distribution patterns indicate that the endosymbionts are transmitted horizontally from the environment with repeated infection events occurring as the host root tissues grow into the whale bones.

Marine waterlogged woods on the ocean floor provide the foundation for an ecosystem resulting in high biomass and potentially high macrofaunal diversity, similarly to other large organic falls. However, the microorganisms forming the base of wood fall ecosystems remain poorly known. To study the microbial diversity and community structure of sunken woods, we analyzed over 2800 cloned archaeal and bacterial 16S rRNA gene sequences from samples with different geographic locations, depths, and immersion times. The microbial communities from different wood falls were diverse, suggesting that sunken woods provide wide-ranging niches for microorganisms. Microorganisms dwelling at sunken woods change with time of immersion most likely due to a change in chemistry of the wood. We demonstrate, for the first time in sunken woods, the co-occurrence of free-living sulfate-reducing bacteria and methanogens and the presence of sulfide oxidizers. These microorganisms were similar to those of other anaerobic chemoautotrophic environments suggesting that large organic falls can provide similar reduced habitats. Furthermore, quantification of phylogenetic patterns of microbial community assembly indicated that environmental forces (habitat filtering) determined sunken wood microbial community structure at all degradation phases of marine woodfalls. We also include a detailed discussion on novel archaeal and bacterial phylotypes in this newly explored biohabitat.

BACKGROUND: Alvinella pompejana is a representative of Annelids, a key phylum for evo-devo studies that is still poorly studied at the sequence level. A. pompejana inhabits deep-sea hydrothermal vents and is currently known as one of the most thermotolerant Eukaryotes in marine environments, withstanding the largest known chemical and thermal ranges (from 5 to 105°C). This tube-dwelling worm forms dense colonies on the surface of hydrothermal chimneys and can withstand long periods of hypo/anoxia and long phases of exposure to hydrogen sulphides. A. pompejana specifically inhabits chimney walls of hydrothermal vents on the East Pacific Rise. To survive, Alvinella has developed numerous adaptations at the physiological and molecular levels, such as an increase in the thermostability of proteins and protein complexes. It represents an outstanding model organism for studying adaptation to harsh physicochemical conditions and for isolating stable macromolecules resistant to high temperatures. RESULTS: We have constructed four full length enriched cDNA libraries to investigate the biology and evolution of this intriguing animal. Analysis of more than 75,000 high quality reads led to the identification of 15,858 transcripts and 9,221 putative protein sequences. Our annotation reveals a good coverage of most animal pathways and networks with a prevalence of transcripts involved in oxidative stress resistance, detoxification, anti-bacterial defence, and heat shock protection. Alvinella proteins seem to show a slow evolutionary rate and a higher similarity with proteins from Vertebrates compared to proteins from Arthropods or Nematodes. Their composition shows enrichment in positively charged amino acids that might contribute to their thermostability. The gene content of Alvinella reveals that an important pool of genes previously considered to be specific to Deuterostomes were in fact already present in the last common ancestor of the Bilaterian animals, but have been secondarily lost in model invertebrates. This pool is enriched in glycoproteins that play a key role in intercellular communication, hormonal regulation and immunity. CONCLUSIONS: Our study starts to unravel the gene content and sequence evolution of a deep-sea annelid, revealing key features in eukaryote adaptation to extreme environmental conditions and highlighting the proximity of Annelids and Vertebrates.

Global change causes widespread decline of coral reefs. In order to counter the anticipated disappearance of coral reefs by the end of this century, many initiatives are emerging, including creation of marine protected areas (MPAs), reef restoration projects, and assisted evolution initiatives. Such efforts, although critically important, are locally constrained. We propose to build a "Noah's Ark" biological repository for corals that taps into the network of the world's public aquaria and coral reef scientists. Public aquaria will serve not only as a reservoir for the purpose of conservation, restoration, and research of reef-building corals but also as a laboratory for the implementation of operations for the selection of stress-resilient and resistant genotypes. The proposed project will provide a global dimension to coral reef education and protection as a result of the involvement of a network of public and private aquaria.

The article describes the initial use of a new generation of national tests by Mexico’s institute of educational evaluation (Instituto Nacional para la Evaluacion de la Educacion—INEE) among sample groups of students who are representative in national and state terms. The aim is to evaluate the quality of the national education system, based on achievement attained in elementary and junior high school. A description is given of the objectives and principles assumed by INEE in evaluating learning, as well as the framework of reference of examinations of educational achievement and quality. The characteristics of national tests are defined: criteria, alignment with the national curriculum and the design matrix. The process is detailed for designing, constructing, applying and validating these examinations. The conclusion discusses the need to have evaluative instruments of quality to comply with the goals of INEE and thus help to improve education in Mexico.

Deep Underground laboratories are unique environments for exploring the impact of ultralow radioactivity on living organisms. They also provide unique features for running long term controlled low-dose experiments.Evolution is an on-going process, and it can be studied experimentally in organisms with rapid generations. The E. coli Long-Term Evolution Experiment (LTEE) is an ongoing study in experimental evolution begun by Richard Lenski at the University of California, which has been tracking genetic changes in 12 initially identical populations of asexual Escherichia coli bacteria since 24 February 1988 on more than 60.000 generations.A first evolution experiment conducted at Modane Underground Laboratory with the same E. Coli strain and the same growth medium used by Richard Lensky and collaborators has shown no change in the fitness trajectory over 500 generations when radiative background was reduced by a factor 6 from 150 to 26 nGy/hr. Monte-Carlo simulation of the experimental set-up showed that 40K in the E. Coli culture medium (Davis Medium) was the almost exclusive source of radioactivity to the bacterial strains, representing 99% of the dose received.Potassium has three naturally occurring isotopes: 39K (93.258%) and 41K (6.730%) are stable, while 40K (0.012%) is radioactive, with a half-life of 1.25 billion years. As 40K in the nutritive medium was the main obstacle to the reduction of the dose received by the bacterial strains during this experiment, depleting 40K in the potassium used to feed the bacteria would reduce significantly the dose received and allow exploring further the ultralow radioactivity frontier. Reciprocally, enriching the potassium in 40K would increase the dose absorbed by the bacteria without changing any other physico-chemical parameters.We therefore propose to compare the fitness trajectories over 1000 generations of the same E. Coli strain using Davis Medium (DM) nutritive media either enriched or depleted in 40K. Although the isotopic composition of natural Potassium is very stable, potassium enriched in 39K and depleted 10 times in 40K can be purchased from commercial vendors for less than 10 € per milligram.  To enrich natural potassium in 40K, a promising approach is through neutron irradiation.Repeating the same experiment using DM nutritive media that differ only by the isotopic composition of the potassium allows isolating the sole impact of radiation on the evolutionary path of the bacteria. Increasing 40K isotopic fraction increases proportionally the absorbed dose and radiation induced mutations are expected to modify the strain evolutionary paths when they exceed the spontaneous mutation rate.These experiments could be performed in several Deep Underground Laboratories to compare the observed fitness trajectories and quantify the reproducibility of the observed evolutionary paths.    

El Instituto Nacional de Evaluacion Educativa (INEE) tiene entre sus funciones la coordinacion de la participacion del Estado espanol en las evaluaciones externas internacionales, entre las que se encuentran PISA, TALIS, PIAAC, PIRLS y TIMSS. En esta comunicacion nos centramos en los resultados obtenidos por Espana en la competencia cientifica en PISA 2009 y TIMSS 2011. Se presentan, por un lado, los rendimientos obtenidos endichos estudios, lo cual permite comparar sistemas educativos de los paises participantes. Y por otro lado, los porcentajes de alumnos que se situan en cada nivel de rendimiento. Por ultimo, se hace una breve resena a los canales de comunicacion que dispone el INEE para la difusion de la informacion generada por los diferentes estudios de evaluacion del sistema educativo que coordina.