Variation in the isotopic signatures of juvenile gray snapper (Lutjanus griseus) from five southern Florida region

Measurements of 18O/16O and 13C/12C ratios in the carbonate of juvenile gray snapper (Lutjanus griseus) sagittal otoliths collected during 2001–2005 from different southern Florida regions indicated significant variations in the ratios between Florida Bay and surrounding areas. Annual differences in isotopic composition were also observed. Classification accuracy of individual otoliths to a region averaged 80% (63% to 96%), thereby enabling the probability of assigning an unknown individual to the appropriate juvenile nursery habitat. Identification of isotopic signatures in the otoliths of gray snapper from Florida Bay and adjacent ecosystems may be important for distinguishing specific portions of the bay that are crucial nursery grounds for juveniles. Separation of gray snapper between geographic regions and nursery sites is possible and has the potential to establish a link between adult gray snapper present on offshore reefs and larvae and juveniles at nursery habitats in Florida Bay or adjacent areas

Bias in culture-independent assessments of microbial biodiversity in the global ocean

On the basis of 16S rRNA gene sequencing, the SAR11 clade of marine bacteria has almost universal distribution, being detected as abundant sequences in all marine provinces. Yet SAR11 sequences are rarely detected in fosmid libraries, suggesting that the widespread abundance may be an artefact of PCR cloning and that SAR 11 has a relatively low abundance. Here the relative abundance of SAR11 is explored in both a fosmid library and a metagenomic sequence data set from the same biological community taken from fjord surface water from Bergen, Norway. Pyrosequenced data and 16S clone data confirmed an 11-15% relative abundance of SAR11 within the community. In contrast not a single SAR11 fosmid was identified in a pooled shotgun sequenced data set of 100 fosmid clones. This under-representation was evidenced by comparative abundances of SAR11 sequences assessed by taxonomic annotation; functional metabolic profiling and fragment recruitment. Analysis revealed a similar under-representation of low-GC Flavobacteriaceae. We speculate that the fosmid bias may be due to DNA fragmentation during preparation due to the low GC content of SAR11 sequences and other underrepresented taxa. This study suggests that while fosmid libraries can be extremely useful, caution must be used when directly inferring community composition from metagenomic fosmid libraries

Genome Sequence of Stenotrophomonas maltophilia PML168, Which Displays Baeyer-Villiger Monooxygenase Activity

Stenotrophomonas maltophilia PML168 was isolated from Wembury Beach on the English Coast from a rock pool following growth and selection on agar plates. Here we present the permanent draft genome sequence, which has allowed prediction of function for several genes encoding enzymes relevant to industrial biotechnology, including a novel flavoprotein monooxygenase

Natural variability of surface oceanographic conditions in the offshore Gulf of Mexico

AbstractThis work characterizes patterns of temporal variability in surface waters of the central Gulf of Mexico. We examine remote-sensing based observations of sea surface temperature (SST), wind speed, sea surface height anomaly (SSHA), chlorophyll-a concentration (Chl-a) and Net Primary Production (NPP), along with model predictions of mixed layer depth (MLD), to determine seasonal changes and long-term trends in the central Gulf of Mexico between the early 1980s and 2012. Specifically, we examine variability in four quadrants of the Gulf of Mexico (water depth >1000m). All variables show strong seasonality. Chl-a and NPP show positive anomalies in response to short-term increases in wind speed and to cold temperature events. The depth of the mixed layer (MLD) directly and significantly affects primary productivity throughout the region. This relationship is sufficiently robust to enable real-time estimates of MLD based on satellite-based estimates of NPP. Over the past 15–20years, SST, wind speed, and SSHA show a statistically significant, gradual increase. However, Chl-a and NPP show no significant trends over this period. There has also been no trend in the MLD in the Gulf of Mexico interior. The positive long-term trend in wind speed and SST anomalies is consistent with the warming phase of the Atlantic Multidecadal Oscillation (AMO) that started in the mid-90s. This also coincides with a negative trend in the El Niño/Southern Oscillation Multivariate ENSO Index (MEI) related to an increase in the frequency of cooler ENSO events since 1999–2000. The results suggest that over decadal scales, increasing temperature, wind speed, and mesoscale ocean activity have offsetting effects on the MLD. The lack of a trend in MLD anomalies over the past 20years explains the lack of long-term changes in chlorophyll concentration and productivity over this period in the Gulf. Understanding the background of seasonal and long-term variability in these ocean characteristics is important to interpret changes in ocean health due to episodic natural and anthropogenic events and long term climate changes or development activities. With this analysis we provide a baseline against which such changes can be measured

Inclusion of Students with Special Education Needs in French as a Second Language Programs: A Review of Canadian Policy and Resource Documents

This article describes a document analysis of policy and resource documents pertaining to inclusion of students with special education needs (SSEN) in Canadian French as a Second Language (FSL) programs.  By recognizing gaps and acknowledging advancements, we aim to inform current implementation and future development of inclusive policy. Document analysis of a) special education documents and b) FSL policy and support documents revealed that over 80% of provincial and territorial education ministries currently refer to inclusion of SSEN in FSL. With the intent of remediating identified inconsistencies in actual application, this article concludes with specific recommendations to enhance inclusive practice

Greenalite Nanoparticles in Alkaline Vent Plumes as Templates for the Origin of Life

Mineral templates are thought to have played keys roles in the emergence of life. Drawing on recent findings from 3.45–2.45 billion-year-old iron-rich hydrothermal sedimentary rocks, we hypothesize that greenalite (Fe₃Si₂O₅ (OH)₄) was a readily available mineral in hydrothermal environments, where it may have acted as a template and catalyst in polymerization, vesicle formation and encapsulation, and protocell replication. We argue that venting of dissolved Fe²⁺ and SiO₂ (aq) into the anoxic Hadean ocean favored the precipitation of nanometer-sized particles of greenalite in hydrothermal plumes, producing a continuous flow of free-floating clay templates that traversed the ocean. The mixing of acidic, metal-bearing hydrothermal plumes from volcanic ridge systems with more alkaline, organic-bearing plumes generated by serpentinization of ultramafic rocks brought together essential building blocks for life in solutions conducive to greenalite precipitation. We suggest that the extreme disorder in the greenalite crystal lattice, producing structural modulations resembling parallel corrugations (∼22 Å wide) on particle edges, promoted the assembly and alignment of linear RNA-type molecules (∼20 Å diameter). In alkaline solutions, greenalite nanoparticles could have accelerated the growth of membrane vesicles, while their encapsulation allowed RNA-type molecules to continue to form on the mineral templates, potentially enhancing the growth and division of primitive cell membranes. Once self-replicating RNA evolved, the mineral template became redundant, and protocells were free to replicate and roam the ocean realm

Greenalite Nanoparticles in Alkaline Vent Plumes as Templates for the Origin of Life

Mineral templates are thought to have played keys roles in the emergence of life. Drawing on recent findings from 3.45–2.45 billion-year-old iron-rich hydrothermal sedimentary rocks, we hypothesize that greenalite (Fe₃Si₂O₅ (OH)₄) was a readily available mineral in hydrothermal environments, where it may have acted as a template and catalyst in polymerization, vesicle formation and encapsulation, and protocell replication. We argue that venting of dissolved Fe²⁺ and SiO₂ (aq) into the anoxic Hadean ocean favored the precipitation of nanometer-sized particles of greenalite in hydrothermal plumes, producing a continuous flow of free-floating clay templates that traversed the ocean. The mixing of acidic, metal-bearing hydrothermal plumes from volcanic ridge systems with more alkaline, organic-bearing plumes generated by serpentinization of ultramafic rocks brought together essential building blocks for life in solutions conducive to greenalite precipitation. We suggest that the extreme disorder in the greenalite crystal lattice, producing structural modulations resembling parallel corrugations (∼22 Å wide) on particle edges, promoted the assembly and alignment of linear RNA-type molecules (∼20 Å diameter). In alkaline solutions, greenalite nanoparticles could have accelerated the growth of membrane vesicles, while their encapsulation allowed RNA-type molecules to continue to form on the mineral templates, potentially enhancing the growth and division of primitive cell membranes. Once self-replicating RNA evolved, the mineral template became redundant, and protocells were free to replicate and roam the ocean realm

Evidence for anoxic shallow oceans at 2.45 Ga: Implications for the rise of oxygenic photosynthesis

Geochemical proxies indicate that atmospheric oxygen levels were <10–5 times present atmospheric levels (10–5 × PAL) until the start of the Great Oxidation Event (GOE; 2.33 Ga). However, trace metal and isotopic data from sedimentary rocks have been interpreted to reflect the presence of oxygenated surface oceans ≥2.5 b.y. ago, implying decoupling of the atmosphere and shallow marine systems. Evidence for oxygen in shallow oceans has fueled the idea that oxygenic photosynthesis evolved long before the GOE and that oxygen did not accumulate in the atmosphere because it was scavenged by reductants such as dissolved Fe2+, a process thought by some to have formed banded iron formations (BIFs). Here we present high-resolution microscopy showing that 2.45 Ga shallow-water BIFs were deposited as ferrous iron-rich muds dominantly composed of greenalite; these muds were rapidly cemented by silica on the seafloor, and subsequently eroded and redeposited as intraformational chert clasts. Our experimental results and kinetic models show that the accumulation of greenalite required seawater oxygen concentrations <10–6 × PAL on the shallow shelf. We infer that oxygen levels of the surface oceans and atmosphere were not decoupled 2.45 b.y. ago, but that both were exceedingly low (<10–5 × PAL). Our findings support the hypothesis that oxygenic photosynthesis evolved shortly before atmospheric oxygenation and was a direct cause of the GOE