Development of release methods for critically endangered freshwater pearl mussels (Margaritifera margaritifera)

Biodiversity loss is a global problem with freshwater bivalves considered amongst the most
endangered biota. The freshwater pearl mussel, Margaritifera margaritifera, is declining
throughout its range owing to habitat degradation and overexploitation. In most of its range,
populations are regarded as reproductively non-functional which has led to the development
of captive breeding programmes. A novel method of releasing M. margaritifera was trialled,
with captive-bred juveniles being released into the rivers caged in ‘mussels silos’ (protective
concrete domes with ventilation creating upwelling to ensure water through flow). We
released 240 juvenile mussels and survival and growth rates were monitored for 18 months
post-release for three size classes: A (13.01-20.00mm); B (10.01-13.00mm); and C (4.01-
10.00mm). We explicitly tested two experimental treatments; one where sediment was added
to each silo (allowing mussels to orientate and burrow) and one without sediment. Survival
by the end of the experiment at month 18 was significantly higher for the largest size class at
97% (though growth was lowest in this cohort), and lowest for the smallest size class at 61%
(though growth was highest in this cohort). Survival and growth were unaffected by the
experimental treatment suggesting that adding sediment offered no advantage. Growth was
positively correlated with both water temperature and the particle size of suspended solids
(both of which were collinear, peaking in summer). There are a large number of ex situ
breeding programmes for freshwater pearl mussels throughout Europe and our finding
suggest that the use of ‘mussel silos’ could be a useful tool to protecting juvenile mussels
allowing them to be released at a relatively early stage of development, minimising the risk of
domestication.

GPS inferred velocity and strain rate fields in eastern Canada

La vallée du fleuve Saint-Laurent, dans l’est du Canada, est l’une des régions sismiques les plus actives dans l’est de l’Amérique du Nord et est caractérisée par de nombreux tremblements de terre intraplaques. Après la rotation rigide de la plaque tectonique, l’ajustement isostatique glaciaire est de loin la plus grande source de signal géophysique dans l’est du Canada. Les déformations et les vitesses de déformation de la croûte terrestre de cette région ont été étudiées en utilisant plus de 14 ans d’observations (9 ans en moyenne) de 112 stations GPS fonctionnant en continu. Le champ de vitesse a été obtenu à partir de séries temporelles de coordonnées GPS quotidiennes nettoyées en appliquant un modèle combiné utilisant une pondération par moindres carrés. Les vitesses ont été estimées avec des modèles de bruit qui incluent les corrélations temporelles des séries temporelles des coordonnées tridimensionnelles. Le champ de vitesse horizontale montre la rotation antihoraire de la plaque nord-américaine avec une vitesse moyenne de 16,8±0,7 mm/an dans un modèle sans rotation nette (no-net-rotation) par rapport à l’ITRF2008. Le champ de vitesse verticale confirme un soulèvement dû à l’ajustement isostatique glaciaire partout dans l’est du Canada avec un taux maximal de 13,7±1,2 mm/an et un affaissement vers le sud, principalement au nord des États-Unis, avec un taux typique de −1 à −2 mm/an et un taux minimum de −2,7±1,4 mm/an. Le comportement du bruit des séries temporelles des coordonnées GPS tridimensionnelles a été analysé en utilisant une analyse spectrale et la méthode du maximum de vraisemblance pour tester cinq modèles de bruit: loi de puissance; bruit blanc; bruit blanc et bruit de scintillation; bruit blanc et marche aléatoire; bruit blanc, bruit de scintillation et marche aléatoire. Les résultats montrent que la combinaison bruit blanc et bruit de scintillation est le meilleur modèle pour décrire la partie stochastique des séries temporelles. Les amplitudes de tous les modèles de bruit sont plus faibles dans la direction nord et plus grandes dans la direction verticale. Les amplitudes du bruit blanc sont à peu près égales à travers la zone d’étude et sont donc surpassées, dans toutes les directions, par le bruit de scintillation et de marche aléatoire. Le modèle de bruit de scintillation augmente l’incertitude des vitesses estimées par un facteur de 5 à 38 par rapport au modèle de bruit blanc. Les vitesses estimées de tous les modèles de bruit sont statistiquement cohérentes. Les paramètres estimés du pôle eulérien de rotation pour cette région sont légèrement, mais significativement, différents de la rotation globale de la plaque nord-américaine. Cette différence reflète potentiellement les contraintes locales dans cette région sismique et les contraintes causées par la différence des vitesses intraplaques entre les deux rives du fleuve Saint-Laurent. La déformation de la croûte terrestre de la région a été étudiée en utilisant la méthode de collocation par moindres carrés. Les vitesses horizontales interpolées montrent un mouvement cohérent spatialement: soit un mouvement radial vers l’extérieur pour les centres de soulèvement maximal au nord et un mouvement radial vers l’intérieur pour les centres d’affaissement maximal au sud, avec une vitesse typique de 1 à 1,6±0,4 mm/an. Cependant, ce modèle devient plus complexe près des marges des anciennes zones glaciaires. Basées selon leurs directions, les vitesses horizontales intraplaques peuvent être divisées en trois zones distinctes. Cela confirme les conclusions d’autres chercheurs sur l’existence de trois dômes de glace dans la région d’étude avant le dernier maximum glaciaire. Une corrélation spatiale est observée entre les zones de vitesses horizontales intraplaques de magnitude plus élevée et les zones sismiques le long du fleuve Saint-Laurent. Les vitesses verticales ont ensuite été interpolées pour modéliser la déformation verticale. Le modèle montre un taux de soulèvement maximal de 15,6 mm/an au sud-est de la baie d’Hudson et un taux d’affaissement typique de 1 à 2 mm/an au sud, principalement dans le nord des États-Unis. Le long du fleuve Saint-Laurent, les mouvements horizontaux et verticaux sont cohérents spatialement. Il y a un déplacement vers le sud-est d’une magnitude d’environ 1,3 mm/an et un soulèvement moyen de 3,1 mm/an par rapport à la plaque l’Amérique du Nord. Le taux de déformation verticale est d’environ 2,4 fois plus grand que le taux de déformation horizontale intraplaque. Les résultats de l’analyse de déformation montrent l’état actuel de déformation dans l’est du Canada sous la forme d’une expansion dans la partie nord (la zone se soulève) et d’une compression dans la partie sud (la zone s’affaisse). Les taux de rotation sont en moyenne de 0,011°/Ma. Nous avons observé une compression NNO-SSE avec un taux de 3.6 à 8.1 nstrain/an dans la zone sismique du Bas-Saint-Laurent. Dans la zone sismique de Charlevoix, une expansion avec un taux de 3,0 à 7,1 nstrain/an est orientée ENE-OSO. Dans la zone sismique de l’Ouest du Québec, la déformation a un mécanisme de cisaillement avec un taux de compression de 1,0 à 5,1 nstrain/an et un taux d’expansion de 1.6 à 4.1 nstrain/an. Ces mesures sont conformes, au premier ordre, avec les modèles d’ajustement isostatique glaciaire et avec la contrainte de compression horizontale maximale du projet World Stress Map, obtenue à partir de la théorie des mécanismes focaux (focal mechanism method).

Efeito de agentes de controle sobre a qualidade reprodutiva de rainhas de Apis mellifera L. (Hymenoptera: Apidae) africanizadas

The agriculture with the use of products with less environmental impact is expanding. In it, the producers offer their products without the use of synthetic chemical inputs, solving the phytosanitary problems with the use of biological or alternative control agents such as parasites, predators, entomopathogenic, alternative products, plant extracts and essential oils. These products can be considered safe to non-target organisms, but studies are needed to find these features on natural enemies and on the beneficial insects such as bees, common frequenter of cultures. In this sense, this study aims to evaluate the effects of control over reproductive quality queens of Apis mellifera L. (Hymenoptera: Apidae) Africanized. For this, it tested the action of control products on the production of A. mellifera queens, using the commercial entomopathogenic fungus Boveril® 1,0x108 (Beauveria bassiana) and aqueous extract of pomegranate (Punica granatum) at a concentration of 5% sterile distilled water with Tween (0.01%) and sterile distilled water (controls). The treatments were incorporated into a tissue type gauze, wrapped in an acrylic plate and packed inside minirrecrias type colonies for the production of queens on the day before the transfer of larvae. The next day were introduced battens with 30 domes with larvae to produce queens, so the workers have contacted the agent tested. From the emergence of all the queens, they were monitored to determine the measures of body weight (mg), length and width of wing and abdomen, length, width and height of the chest (mm) as well as the time of emergence of queens. The next step was evaluated the influence of the control agents in production creates, performing measurements of creating areas in cm2 for six straight weeks. It was found that the area creates Queens did not differ among the treatments. Histological analysis of hipofaringeanas of workers glands that came into contact with the control agents and the midgut of virgin queens were also held. Histological analysis differences were observed in the tissues when the treatments were compared with the respective controls.

Géodiversité sous-marine de Nouvelle-Calédonie. 1ère partie

The object of this article is to offer a synthesis of the knowledge clarifying the originality and the diversity of the submarine geological formations of the New Caledonian EEZ. A reminder is given onto the geologic history of the region, based upon the dislocation of the Gondwana Continent, the opening of the Tasman Sea, the presence of submarine volcanism, the setting up of heavy peridotitic rocks, the building up of the Fairway and Lord Howe Ridges and of sedimentary basins, the formation of volcanic domes and sea-mounts or guyots, the subduction along the Vanuatu Trench, the uplift of the Loyalty Islands, the development of carbonated ptatforms around the islands etc.... Of this complex history ensues an exceptional submarine geo-diversity. After this presentation the article clarifies the methods and the tools used in marine geosciences to map, explore, observe, analyze, sample, that they are embarked or are autonomous, teleoperated or inhabited systems. A chapter describes the programs which were set up since about forty years and the results obtained as well as the scientific teams concerned with. In conclusion, based on the unpublished character of this geo-diversity, the article introduces the second text to come in a next issue of theTai Kona magazine, text which will focus on the scientific, economic (mineral resources), environmental (deep biodiversity) and risks (seismicity) challenges that are worn by one of the most original submarine geologic context in the world.

Upper lower triassic stromatolite from Anhui, South China: geobiologic features and paleoenvironmental implications

Widespread stromatolites and other microbialite deposits characterize Lower Triassic marine successions worldwide. This study documents a stromatolite deposit, 1.1. m thick, from the upper Spathian (Lower Triassic) of the Susong area, South China. The stromatolite comprises distinct laminated domes in the basal part and columns at the upper part. Dark laminae are loosely spaced and interlayered with thicker light colored laminae. Diffusive dark colored laminae are composed of peloidal micrite that grade locally into microclotted structures, and yield copies of bacteria clump-like and coccoid-like spheroid aggregates. The former are characterized by cloudy, micrite nuclei rimmed by coarse-grained, euhedral sparry calcite crystals, while the latter are comprised of solid calcite crystal nuclei coated with rather thin micrite envelopes. The cloudy, micrite nuclei resemble bacteria clump-like structures observed in present-day travertine. Both the coccoid-like spheroids and bacteria clump-like structures are surrounded by coarse-grained euhedral calcite crystals, suggesting a similar accretion mechanism. Both spherical structures therefore could be crucial in the accretion of the Susong stromatolite. The laminated/microclotted structures are interpreted as the result of variation in timing of lithification relative to the timing of the decay of microbes. Micro-analysis also unravels the common occurrence of authigenic micro-quartz crystals in association with Fe-bearing illite clay minerals in the stromatolite columns. Their coalescing nature with each other, together with the associated pyrite grains, strongly support the formation of micro-quartz crystals from microbial reduction of an Fe-bearing smectite precursor by sulfate reducing bacteria. A comparison of the Susong stromatolite with its counterparts from the upper Lower Triassic strata in Dajiang, South China reveals many similarities in stromatolite microstructures, suggesting that a harsh, euxinic-anoxic environment resulting in the bloom of sulfate reducing bacteria most likely extended into the latest Spathian in South China.

Tectonic evolution of Variscan Iberia: Gondwana–Laurussia

An integrated interpretation of the late Paleozoic structural and geochronological record of the Iberian Massif is presented and discussed under the perspective of a Gondwana-Laurussia collision giving way to the Variscan orogen. Compressional and extensional structures developed during the building of the Variscan orogenic crust of Iberia are linked together into major tectonic events operating at lithosphere scale. A review of the tectonometamorphic and magmatic evolution of the IberianMassif reveals backs and forths in the overall conver- gence between Gondwana and Laurussia during theamalgamation of Pangea in late Paleozoic times. Stages dom- inated by lithosphere compression are characterized by subduction, both oceanic and continental, development of magmatic arcs, (over- and under-) thrusting of continental lithosphere, and folding. Variscan convergence re- sulted in the eventual transference of a large allochthonous set of peri-Gondwanan terranes, the Iberian Allochthon, onto the Gondwana mainland. The Iberian Allochthon bears the imprint of previous interaction be- tween Gondwana and Laurussia, including their juxtaposition after the closure of the Rheic Ocean in Lower De- vonian times. Stages governed by lithosphere extension are featured by the opening of two short-lived oceanic basins that dissected previous Variscan orogenic crust, first in the Lower-Middle Devonian, following the closure of the Rheic Ocean, and then in the early Carboniferous, following the emplacement of the peri-Gondwanan allochthon. An additional, major intra-orogenic extensional event in the early-middle Carboniferous dismem- bered the Iberian Allochthon into individual thrust stacks separated by extensional faults and domes. Lateral tec- tonics played an important role through the Variscan orogenesis, especially during the creation of new tectonic blocks separated by intracontinental strike-slip shear zones in the late stages of continental convergence.