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Invasive species are a major concern both biologically and economically because of the rates at which they spread and their alterations to ecosystems. Zebra mussels (Dreissena polymorpha) are of concern in many regions owing to expenses related to industrial equipment damage and control education efforts. However, their greatest cost may be their ecological impact across North America. We tested pumpkinseed (Lepomis gibbosus) from three populations in Ontario (Canada) to determine if there was variation across populations or sampling periods in the consumption of zebra mussels. Using a combination of stomach content and stable isotope analyses, we found that pumpkinseed diet consisted of primarily zebra mussels across all populations and sampling periods, including a minimum of 54% in all lakes and sampling periods based on stable isotope mixing models. The current resource use patterns of pumpkinseed in our study populations indicate that there has been a shift from their preinvasion diet of benthic littoral invertebrates such as gastropods. The large-scale consumption of invasive mussels by native fishes may have important implications for natural biological control of these mussels, decreasing overall mussel abundance and rate of spread. We discuss our results in the context of their implications for the overall health and dynamics of aquatic ecosystems. Les especes envahissantes constituent une importante preoccupation sur le plan tant biologique qu'economique en raison de la vitesse a laquelle elles se propagent et des modifications qu'elles causent aux ecosystemes. Les moules zebrees (Dreissenapolymorpha) sont preoccupantes dans de nombreuses regions en raison des depenses reliees aux dommages au materiel industriel et aux efforts de sensibilisation a leur controle. Le cout le plus important qui leur est associe pourrait toutefois etre leur impact ecologique dans l'ensemble de l'Amerique du Nord. Nous avons examine des crapets-soleil (Lepomis gibbosus) de trois populations en Ontario (Canada) pour determiner s'ily avait des differences entre populations ou entre periodes d'echantillonnage sur le plan de la consommation de moules zebrees. Sur la base de contenus stomacaux et d'analyses d'isotopes stables, nous avons etabli que le regime alimentaire des crapets-soleil consistait principalement de moules zebrees dans toutes les populations et periodes d'echantillonnage, en constituant au moins 54 % dans tous les lacs et durant toutes les periodes d'echantillonnage, selon les modeles de melange d'isotopes stables. Les habitudes actuelles d'utilisation des ressources des crapets- soleil dans les populations etudiees indiquent que leur alimentation, constituee, avant l'invasion, d'invertebres cotiers benthiques tels que des gasteropodes, a depuis change. La consommation a grande echelle de moules envahissantes par des poissons indigenes pourrait avoir d'importantes consequences pour le controle biologique naturel de ces moules, en reduisant l'abondance globale et la vitesse de propagation des moules. Nous discutons de nos resultats en ce qui concerne la sante et la dynamique globales des ecosystemes aquatiques. [Traduit par la Redaction], Introduction Invasive species are among the top threats to global biodiversity and ecosystem stability (Ricciardi et al. 1998; Sousa et al. 2013), particularly in aquatic environments that have been subject [...]

Relationships between morphological traits and their ecological function frequently result in patterns that are consistently observed within taxa. Across fishes, the field of ecomorphology has identified a number of morphological traits linked to foraging tactic. Here we examined the links between morphology and diet in pumpkinseed sunfish (Lepomis gibbosus (L., 1758)) from three temperate freshwater lakes. We focused on morphological variation in pharyngeal jaw and gill raker structures, both involved with the processing of prey after capture, in relation to diet. Using stomach contents and stable isotope analysis, we established mean resource use estimates for both populations and individual fish. Among populations and individuals within lakes, we observed that pharyngeal jaw size and gill raker spacing increased with the consumption of littoral prey (e.g., hard-shelled snails) relative to pelagic prey (e.g., zooplankton), but the morphological changes were greater for the pharyngeal jaws. Overall, the relationships that we observed between morphology and foraging tactic were consistent with patterns observed in pumpkinseed and across other fishes. Individual-level diet variation associated with morphology may result in phenotypic diversity within populations that has multiple ecological and evolutionary implications for these populations. Key words: Dreissena polymorpha, ecomorphology, gill rakers, internal morphology, Lepomis gibbosus, pharyngeal jaw, phenotypic plasticity, resource polymorphism, stable isotopes. Les liens entre les caracteres morphologiques et leur fonction ecologique se traduisent souvent par des motifs uniformement observes au sein de taxons. En ce qui concerne les poissons, l'ecomorphologie a cerne un certain nombre de caracteres morphologiques associes aux tactiques d'alimentation. Nous examinons les liens entre la morphologie et le regime alimentaire chez des crapets-soleil (Lepomis gibbosus (L., 1758)) de trois lacs d'eau douce temperes. Nous nous penchons plus particulierement sur les variations morphologiques en fonction du regime alimentaire des structures de la machoire pharyngienne et des branchiospines, qui interviennent toutes deux dans la transformation des proies apres leur capture. A la lumiere de contenus stomacaux et de l'analyse d'isotopes stables, nous avons etabli des estimations de l'utilisation moyenne des ressources tant pour les populations que les poissons individuels. Entre les populations et entre les individus d'un meme lac, nous avons observe que plus la consommation de proies littorales (p. ex. escargots a coquille dure) etait grande par rapport a celle de proies pelagiques (p. ex. zooplancton), plus la taille des machoires pharyngiennes et l'espacement des branchiospines etaient importants, cette variation morphologique etant toutefois plus grande pour les machoires pharyngiennes. Globalement, les relations que nous avons observees entre la morphologie et les tactiques d'alimentation concordent avec les motifs deja observes chez les crapets-soleil et chez d'autres poissons. Les variations du regime alimentaire associees a la morphologie entre individus pourraient se traduire par une diversite phenotypique au sein des populations qui aurait de multiples consequences en ce qui concerne l'ecologie et revolution de ces populations. [Traduit par la Redaction] Mots-cles: Dreissena polymorpha, ecomorphologie, branchiospines, morphologie interne, Lepomis gibbosus, machoire pharyngienne, plasticite phenotypique, polymorphisme des ressources, isotopes stables., Introduction The field of ecomorphology identifies relationships between morphological traits and ecological processes, such as resource use (e.g., Motta and Kotrschal 1991; Wainwright 1996). Biologists have identified patterns between morphological [...]

Endogenous markers are a valuable indicator of individual animal ecology, but data interpretation requires a detailed understanding of the timing of tissue formation. Fur is commonly used in bat research using endogenous markers, but the moulting cycles of most bat species are not well documented. In this review, we (i) describe methods of investigating bat moulting; (ii) summarize the current literature on bat moulting cycles, highlighting broad trends; (iii) discuss knowledge gaps; and (iv) make recommendations for optimal fur sampling protocols. Three characteristics may indicate moulting in bats: changing skin pigmentation; visible fur growth and colour changes; and endogenous markers. Most studies reported new fur growth once annually during summer-fall, although there were exceptions. The timing of new fur growth varies among species, sexes, and age classes. Individuals commonly experience asynchronous new fur growth, with dorsal fur growth occurring before ventral. Specific moult progressions vary among species. Knowledge gaps include moulting cycles in tropical species and in subadult and yearling bats; migration during new fur growth; and the timing of fur growth compared with shedding. We recommend that fur samples taken dorsally from adult males are the most likely to be representative of the bat's site of summer residency. Key words: bats, fur, moulting or molting cycle, endogenous markers, review. Si les marqueurs endogenes constituent un indicateur utile de l'ecologie individuelle des animaux, l'interpretation de ces donnees necessite une comprehension detaillee du moment de la formation des tissus. Bien que le poil soit couramment utilise dans la recherche sur les chauves-souris axee sur des marqueurs endogenes, les cycles de mue de la plupart des especes de chauves-souris ne sont pas bien documentes. Dans le present article, nous (i) decrivons des methodes permettant d'etudier la mue des chauves-souris, (ii) presentons une synthese des travaux existants sur les cycles de mue des chauves-souris pour en faire ressortir de grandes tendances, (iii) abordons les lacunes sur le plan des connaissances et (iv) formulons des recommandations relatives a des protocoles optimaux d'echantillonnage du poil. Trois caracteristiques pourraient indiquer qu'une chauve-souris est en mue, a savoir : un changement de la pigmentation de la peau, la croissance et des changements de couleur visibles des poils, ainsi que des marqueurs endogenes. Bien qu'il existe des exceptions, la plupart des etudes font etat d'une croissance de nouveaux poils une fois l'an, a l'ete-l'automne. Le moment de la croissance de nouveaux poils varie selon l'espece, le sexe et la classe d'age. Les individus presentent souvent une croissance non synchrone de nouveaux poils, la croissance des poils dorsaux etant plus hative que celle des poils ventraux. La progression de la mue varie egalement selon l'espece. Les lacunes sur le plan des connaissances touchent notamment aux cycles de mue des especes tropicales et des chauves-souris subadultes et d'un an, a la migration durant la croissance de nouveaux poils et au moment de la croissance de poils par rapport a celui de la perte de poils. Nous suggerons que les echantillons de poils dorsaux provenant de males adultes sont les plus susceptibles d'etre representatifs du lieu de residence estivale d'une chauve-souris. [Traduit par la Redaction] Mots-cles: chauves-souris, poils, mue ou cycle de mue, marqueurs endogenes, article de synthese., Introduction Analyses of endogenous biogeochemical markers in animal tissues are increasingly capable of informing our understanding of animal movement (e.g., Hobson and Wassenaar 2008; Kaimal et al. 2009; Sellick et [...]

We used stable carbon and nitrogen isotope compositions of hair and liver as a way of examining seasonal diet changes and explaining seasonal breeding in deer mice (Peromyscus maniculatus (Wagner, 1845)). Summer and winter δ[sup.13]C values differed, which is attributed to the availability of different plant tissues ([C.sub.3] plants). The δ[sup.15]N values of liver showed a decrease in consumed animal protein during winter, but the difference was not large enough to indicate a full trophic level change in diet from summer to winter. The δ[sup.15]N values of hair remained constant across the seasons, which is attributed to a continuous level of moulting throughout the year. Our data indicate that lowered food quality in the form of reduced dietary animal protein intake may play a role in the cessation of breeding in deer mice in winter. Les compositions des isotopes stables de carbone et d'azote dans le poil et le foie nous ont servi a examiner les changements saisonniers de regime alimentaire et a expliquer la reproduction saisonniere chez les souris du crepuscule (Peromyscus maniculatus (Wagner, 1845)). Il y a des differences entre les valeurs estivales et hivernales de δ[sup.13]C, ce qui s'explique par la disponibilite de tissus vegetaux diffeerents (plantes [C.sub.3]). Les valeurs de δ[sup.15]N du foie indiquent une diminution de la consommation de proteines animales durant l'hiver, mais la difference n'est pas suffisamment importante pour representer un changement complet de niveau trophique du regime de l'ete a celui de l'hiver. Les valeurs de δ[sup.15]N du poil demeurent stables au cours des saisons, ce qui est explique par un niveau constant de mue au cours de l'annee. Nos donnees indiquent que la qualite reduite de la nourriture a cause de la diminution d'ingestion de proteines animales dans le regime peut jouer un role dans l'interruption de la reproduction chez les souris du crepuscule en hiver. [Traduit par la Redaction], Introduction Seasonal breeding is a prominent life-history strategy in temperate and northern birds and mammals (Fournier et al. 1999). The reallocation hypothesis and the increased demand hypothesis each endeavour to [...]

The stable isotopic compositions of nitrogen and carbon in animal tissues reflect diet. However, factors other than diet can also affect these stable isotope ratios, leading to misinterpretations of diet composition. To test the hypothesis that variation in metabolic rate alters the isotopic compositions of tissues, deer mice (Peromyscus maniculatus (Wagner, 1845)) were kept at three temperatures (thermoneutral (23°C), cool (5°C), and cold (-10°C)) and fed ad libitum. The changes in carbon and nitrogen isotope compositions of liver associated with the thermoneutral versus cool and cold conditions were very small in comparison with those arising from differences in diet. We conclude that temperature-induced variations in metabolic rate are insufficient to produce differences in the stable carbon or nitrogen isotope compositions that could be mistaken for changes in diet. Les compositions d'isotopes stables d'azote et de carbone dans les tissus animaux refletent le regime alimentaire. Cependant, des facteurs autres que le regime peuvent affecter ces rapports d'isotopes stables, ce qui entraine des interpretations erronees de la composition du regime alimentaire. Afin de tester l'hypothese qui veut que la variation du taux metabolique affecte la composition isotopique des tissus, nous avons garde des souris du crepuscule (Peromyscus maniculatus (Wagner, 1845)) a trois temperatures differentes, soit des regimes thermiques neutre (23°C), frais (5°C) et froid (-10°C), et les avons nourries a volonte. Les modifications dans les compositions d'isotopes de carbone et d'azote dans le foie associees au regime thermique neutre par rapport a ceux des regimes frais et froids sont tres petites par comparaison a celles qui proviennent de differences de regime alimentaire. Nous en concluons que les variations du taux metabolique causees par la temperature ne sont pas assez importantes pour produire des differences de composition des isotopes stables de carbone et d'azote qui pourraient etre interpretees par erreur comme des changements de regime alimentaire. [Traduit par la Redaction], Introduction Measurement of stable carbon ([sup.13]C/[sup.12]C) and nitrogen ([sup.15]N/[sup.14]N) isotope ratios is commonly undertaken in ecological studies because the compositions of tissues reflect the composition of the diet (Kelly 2000). [...]

Detailed mapping of a portion of the North Spirit Lake greenstone belt reveals a basal basaltic volcanic unit (ca. 3 Ga) with a komatiitic component and strong major and trace element geochemical affinity with typical mid-ocean ridge basalts (e.g., N-MORB). The overlying transitional unit includes basaltic tufts, which have close geochemical affinity to the underlying basalts, and to N-MORB. Interbedded with and overlying the tufts is a thin, laterally continuous sulfide-rich unit with chert interbeds, which is in turn over-lain by interbedded carbonate, chert, and iron-rich sedimentary rocks. The chemical sedimentary rocks of the transitional unit display rare-earth element (REE) patterns and positive Eu anomalies consistent with derivation from fluids associated with submarine hydrothermai vent fields. The sulfide unit is interpreted to represent proximal hydrothermal vent deposits derived from black smoker activity near a spreading center. The overlying carbonate and chert mounds and beds are interpreted as hydrothermal deposits formed at lower temperatures in a more distal setting relative to the spreading center. The carbonate deposits may have formed in an environment analogous to that of the Lost City hydrothermai field (Kelley et al., 2001), where abundant chimneys, dendrites, and beds of carbonate are produced ~15 km from the mid-Atlantic rift axis. The basal volcanic unit consequently is interpreted as ocean-floor basalts formed at an Archean spreading center, with the basaltic tufts representing the last volcanic emanations, and with the chemical sediments representing hydrothermalvents deposits both proximal and distal to the spreading center. The capping siliciclastic unit likely is part of an accretionary wedge, possibly representing ocean closure after a protracted seafloor speading episode. The sedimentary rocks were derived in part, from a weathered tonalite-trondhjemite-granodiorite source. The supracrustal rocks of the North Spirit Lake greenstone belt provide an unusually clear window into some tectonic activity on the primitive Earth, including evidence for the existence of ocean-floor basalts, proximal and distal hydrothermal activity, and possibly a protracted cycle of ocean opening and destruction.

Abstract: The dietary habits of most small mammals are not well documented, and stable isotope measurements can provide information on when and how diets change. Here we document the discrimination [...]

Neoproterozoic igneous rocks of the Avalonian Mira terrane, Cape Breton Island, and Caledonia terrane, southern New Brunswick, have experienced regional [sup.18]O-depletion. The majority of these rocks have [[delta].sup.18][O.sub.WR] values between -1 and +6[per thousand], markedly different from igneous rocks of the inboard Ganderian terranes, which have normal-high [[delta].sup.18][O.sub.WR] values of +7 to +12[per thousand]. The [sup.18]O-depletion of these Avalonian terranes resulted from pervasive hydrothermal alteration. All of the igneous rocks contain classic propylitic alteration assemblages of turbid feldspar, chlorite, epidote, sericite, and calcite and host multiple generations of veins containing the same phases. The [[delta].sup.18]O values of the rock-forming minerals show strong disequilibrium with [[DELTA].sub.qtz-fs] ranging from +2.5 to +11.0[per thousand] and [[DELTA].sub.kfs-plg] from -0.5 to +1.0[per thousand]. Such values are indicative of post-magmatic hydrothermal alteration. The hydrothermal alteration occurred at ca. 560-550 Ma during initial transcurrent rifting of Avalonia at the Gondwanan margin. The development of rift-wrench basins with associated bimodal volcanism allowed large volumes of hydrothermal fluids to penetrate and circulate within Mira and Caledonia terrane crust before its submergence in the early Cambrian (ca. 540-530 Ma). The hydrothermal fluids were predominantly meteoric, although the presence of a significant seawater component cannot be ruled out. The almost ubiquitous [sup.18]O-depletion exhibited by the Neoproterozoic rocks in these Avalonian terranes is absent in the associated Ganderian terranes, suggesting that Avalonia remained separate from Ganderia until at least the Cambrian-Ordovician. This [sup.18]O-depletion provides an additional geochemical tool for identification of Avalonian crust in other areas of the Appalachians and Europe. Keywords: Avalonia, peri-Gondwanan, Neoproterozoic, oxygen isotopes, granitoids.

Abstract: The stable isotope composition of carbon and nitrogen in feces can be a useful tool for reconstructing diet. To examine whether the isotopic composition of feces reflect those of [...]

Biofilms found on submerged limestone, granite, sandstone and support pillars of bridges in rivers, host several epilithic microbial communities, due to the presence of organic and inorganic compounds that occur at the solid-liquid interface. Such microorganisms exhibit greater metabolic activity when compared to their planktonic counterparts. Biogeochemical activities are common in natural waters, which have high concentrations of dissolved iron, silicon and aluminum.

An analysis describing the petrogenesis of the Potato Hill Pluton is presented. The pluton is a nested, composite, Grenvillian intrusion found in Newfoundland which is composed of pyroxene-bearing quartz monzodiorite, equigranular biotite plus hornblende plus garnet granite and K-feldspar megacrystic hornblende plus biotite quartz monzodiorite. It is shown that the pluton was created in a transpressional period during a Late-Orogenic stage.

Stable carben-isotope ratios in bone collagen and oxygen-isotope ratios in bone and enamel phosphate were used to reconstruct the degree of immigration that took place in two Teotihuacan neighbourhoods: Tlajinga 33, an apartment compound of craft producers in which there is little archaeological evidence of foreign origin, and Tlailotlacan, a neighbourhood where abundant archaeological evidence suggests that it was settled by Zapotecs from the Oaxaca. About 1/3 of the inhabitants of Tlajinga 33 had grown up elsewhere, but dwelt in Teotihuacan for many years before death. The data suggest achieved status, along with political and/or ethnic assimilation, and support Storey's (1992) hypothesis that because of high morbidity, immigration would have been necessary to maintain population viability. In comparison, Tlailotlacan contained a higher proportion of immigrants (50%) and maintained a distinct ethnic character throughout its occupation. The discovery of immigrants in all time phases suggests that a continuous influx of immigrants may have helped in the maintenance of its ethnicity. These data provide evidence that the social and economic complexities associated with immigration in the earliest urban society in the New World, have analogues with our modern cities. Supported by Social Sciences and Humanities Research Council, Canada and the Natural Sciences and Engineering Research Council, Canada.