Soil microbial ecology needs robust tools to elucidate ecological questions, such as the impact of fertilisation on soil microbial communities. However, the methods and data analysis used can directly affect the biological conclusions. In this study, the sensitivity of terminal-restriction fragment length polyphorism (T-RFLP) to four restriction enzymes (RE), six peak area thresholds (PAT) from 0 to 10 % and two matrices (presence/absence and relative abundance) was assessed on soils subjected to eight different long-term amendments. The T-RFLP profiles were analysed using a three-step multivariate analysis approach: (i) cluster analysis and non-metric multi-dimensional scaling, (ii) ANOSIM and PERMANOVA and (iii) correlations. The application of organic and mineral fertilisers over 53 years changed the bacterial community composition regardless if the RE, PAT and matrix were used. However, the clustering of the community, the strength of these differences, the correlations with environmental variables and, subsequently, the biological conclusions varied with the use of RE, PAT and matrix. Hence, the bacterial community composition was found to be either highly sensitive to any changes in soil organic matter strongly correlated to C and N concentration, or only affected by large inputs of C or soil management. Different REs can reveal different bacterial populations affected by different drivers, but PATs 0.5 and 1 % should be used especially when using presence/absence matrix. This study also shows the complexity of the effect of organic and mineral amendment on bacterial community composition and stresses the importance to inform on methodological and data analysis parameters.

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Acacia senegal (L) Willd. and Acacia seyal Del. are highly nitrogen-fixing and moderately salt tolerant species. In this study we focused on the genetic and genomic diversity of Acacia mesorhizobia symbionts from diverse origins in Senegal and investigated possible correlations between the genetic diversity of the strains, their soil of origin, and their tolerance to salinity. We first performed a multi-locus sequence analysis on five markers gene fragments on a collection of 47 mesorhizobia strains of A. senegal and A. seyal from 8 localities. Most of the strains (60%) clustered with the M. plurifarium type strain ORS 1032T, while the others form four new clades (MSP1 to MSP4). We sequenced and assembled seven draft genomes: four in the M. plurifarium clade (ORS3356, ORS3365, STM8773 and ORS1032T), one in MSP1 (STM8789), MSP2 (ORS3359) and MSP3 (ORS3324). The average nucleotide identities between these genomes together with the MLSA analysis reveal three new species of Mesorhizobium. A great variability of salt tolerance was found among the strains with a lack of correlation between the genetic diversity of mesorhizobia, their salt tolerance and the soils samples characteristics. A putative geographical pattern of A. senegal symbionts between the dryland north part and the center of Senegal was found, reflecting adaptations to specific local conditions such as the water regime. However, the presence of salt does not seem to be an important structuring factor of Mesorhizobium species.

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Ocean grabbing occurs when traditional users, such as small-scale fishers, are pushed aside by new development activities. This grabbing must be prevented to avoid sea uses that maintain or increase social inequity. In this paper, we show that in tropical Atlantic countries, such as Brazil and Senegal, examples of ocean grabbing already occur. In this context, we analyse if Maritime Spatial Planning (MSP) may be an opportunity to limit ocean grabbing or, to the contrary, poses a risk to increase it. MSP calls for an ecosystem approach that requires integrated coastal and marine management and involves stakeholders in developing a shared vision of the future, where society and environment are preserved. However, recent studies have shown that MSP is a process to be used cautiously to ensure equitable decisions. Meanwhile, the concept is spreading worldwide including in tropical Atlantic countries. We highlight that context matters and the specificities of the tropical Atlantic must be taken into account when deploying MSP processes. In the tropical Atlantic context, there is increased imbalances of stakeholder power, traps from decision support tools, and a need for adaptive management. These specific features must be addressed when deploying MSP in a way to avoid ocean grabbing.

La drépanocytose pose un problème de santé publique au Sénégal. Elle concerne principalement les enfants et les adolescents. L'objectif de notre travail était de déterminer les profils épidémiologiques, cliniques et hématologiques de la drépanocytose homozygote SS dans une cohorte d'enfants suivis à l'hôpital de la paix de Ziguinchor. Il s'agit d'une étude rétrospective portant sur des dossiers d'enfants drépanocytaires. Etaient inclus, les drépanocytaires SS âgés entre 2mois et 21ans, reçus en phase inter critique durant la période d'étude allant du 1er Janvier 2015 au 31 Août 2017. N'étaient pas inclus dans l'étude les hétérozygotes composites (SC, S béta thalassémie). Nous avons colligé 46 dossiers de drépanocytaires SS (20 filles et 26 garçons). L'âge moyen des enfants était de 8,0ans [11mois-21ans]. Environ 1/3 des enfants (39,1%) avaient un âge inférieur ou égal à 5 ans. Il y avait une diversité ethnique avec une prédominance de diola (30,2%) suivi de mandingue (27,9%) et de poular (25,6%). L'âge moyen des enfants à la 1ére crise était de 35,5mois [7-192 mois]. Plus de 1/3 des enfants (41,3%) avaient fait une 1ére crise avant le deuxième anniversaire. Le type de la 1ére crise, qu'avait présenté l'enfant, était dominé par la crise vaso-occlusive (32,6%) suivi du syndrome pied-main (30,4%). Les signes cliniques en phase inter critique étaient la pâleur 95,6%); l'ictère (36,9%) et la splénomégalie (21,7%). A l'hémogramme, le nombre de globules blancs moyen était de 12465 leucocytes/mm3 [5340-26900]. L'hyperleucocytose, supérieure à 10 000 leucocytes/mm3 était retrouvée chez 34 malades (73,9%). La totalité des malades présentait une anémie avec une moyenne 08,6 g/dl [05,7-11,8]. Le taux d'hémoglobine S variait entre 54,6 et 98,4%. Le diagnostic et la prise en charge médicale de la drépanocytose SS sont tardifs à Ziguinchor. Le dépistage néonatal pourrait favoriser une prise en charge précoce dans la région.

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