Discovery and mapping of the Triton seep site, Redondo Knoll: fluid flow and microbial colonization within an oxygen minimum zone

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Wagner, J. K. S., Smart, C., & German, C. R. Discovery and mapping of the Triton seep site, Redondo Knoll: fluid flow and microbial colonization within an oxygen minimum zone. Frontiers in Marine Science, 7, (2020): 108, doi:10.3389/fmars.2020.00108.This paper examines a deep-water (∼900 m) cold-seep discovered in a low oxygen environment ∼30 km off the California coast in 2015 during an E/V Nautilus telepresence-enabled cruise. This Triton site was initially detected from bubble flares identified via shipboard multibeam sonar and was then confirmed visually using the remotely operated vehicle (ROV) Hercules. High resolution mapping (to 1 cm resolution) and co-registered imaging has provided us with a comprehensive site overview – both of the geologic setting and the extent of the associated microbial colonization. The Triton site represents an active cold-seep where microorganisms can act as primary producers at the base of a chemosynthesis-driven food chain. But it is also located near the core of a local oxygen minimum zone (OMZ), averaging 100 m across the seafloor, dominate the site, while typical seep-endemic macro-fauna were noticeably absent from our co-registered photographic and high-resolution mapping surveys – especially when compared to all adjacent seep sites within the same California Borderlands region. While such absences of abundant macro-fauna could be attributable to variations in the availability of dissolved oxygen in the overlying water column this need not necessarily be the case. An alternate possibility is that the zonation in microbial activity that is readily observable at the seafloor at Triton reflects, instead, a concentric pattern of radially diminishing fluxes of reductants from the underlying seafloor. This unusual but readily accessible discovery, in close proximity to Los Angeles harbor, provides an intriguing new natural laboratory at which to examine biogeochemical and microbiological interactions associated with the functioning of cold seep ecosystems within an OMZ.Ship time was funded by NOAA – Office of Exploration and Research and the Ocean Exploration Trust. This material is based upon work supported by a National Science Foundation Graduate Research Fellowship (to JW), the Office of Naval Research (to CS), and NASA’s Astrobiology program (to CG)

Microbial Evaluation of the Calamus Heated Gutta-Percha Delivery System

If gutta-percha cartridges are contaminated with bacteria prior to obturation then contamination of the root canal system may result. Successful treatment not only depends on bacterial elimination but also depends on prevention of recontamination. This study was motivated by the observation that endodontists frequently use single use gutta-percha cartridges on multiple patients. The goal of this study was to determine if cross contamination occurred when a single gutta-percha cartridge in the Calamus™ Flow System was used on multiple patients. An effective recovery method was established during a pilot study using Enterococcus faecalis as a sample bacterium. Microbial recovery was obtained using standard media. The Calamus™ heated gutta-percha delivery system was evaluated to determine the percentage of cartridges with recoverable microorganism under four conditions. Results showed that for cartridges tested immediately after removal from manufacturer’s packaging, the observed negative outcome was 0/10 (0%). For cartridges used on a single patient with an alcohol wipe after use, the negative outcome was 0/20 (0%). For cartridges used on a single patient with no alcohol wipe after use, the negative outcome was 1/20 (5%). For cartridges used on three patients with an alcohol wipe after each use, the number of observed negative outcomes was 0/20 (0%). Using 95% score confidence intervals, the results indicate that the percentage of cartridges with recoverable microorganism under the four conditions is below 27.8% for cartridges sampled from manufacturer’s packaging, 16.1% for cartridges used on a single patient with a alcohol wipe after use, 23.6% for cartridges used on a single patient with no alcohol wipe after use, and 16.1% for cartridges used on three patients with an alcohol wipe after each use. Evidence from this study indicates using Calamus™ flow cartridges on multiple patients vs. single patient does not lead to an increased contamination risk

Mining topological relations from the web

Topological relations between geographic regions are of interest in many applications. When the exact boundaries of regions are not available, such relations can be established by analysing natural language information from web documents. In particular we demonstrate how redundancy-based techniques can be used to acquire containment and adjacency relations, and how fuzzy spatial reasoning can be employed to maintain the consistency of the resulting knowledge base

Nanoscale assembly of lanthanum silica with dense and porous interfacial structures

This work reports on the nanoscale assembly of hybrid lanthanum oxide and silica structures, which form patterns of interfacial dense and porous networks. It was found that increasing the molar ratio of lanthanum nitrate to tetraethyl orthosilicate (TEOS) in an acid catalysed sol-gel process alters the expected microporous metal oxide silica structure to a predominantly mesoporous structure above a critical lanthanum concentration. This change manifests itself by the formation of a lanthanum silicate phase, which results from the reaction of lanthanum oxide nanoparticles with the silica matrix. This process converts the microporous silica into the denser silicate phase. Above a lanthanum to silica ratio of 0.15, the combination of growth and microporous silica consumption results in the formation of nanoscale hybrid lanthanum oxides, with the inter-nano-domain spacing forming mesoporous volume. As the size of these nano-domains increases with concentration, so does the mesoporous volume. The absence of lanthanum hydroxide (La(OH)(3)) suggests the formation of La2O3 surrounded by lanthanum silicate

Late Pleistocene pteropods, heteropods and planktonic foraminifera from the Caribbean Sea, Mediterranean Sea and Indian Ocean

Pteropods and heteropods (holoplanktonic gastropods) are an important component of the modern oceans; however, detailed information on their distribution in the fossil record is often based on poorly preserved specimens. This study presents the micropaleontological analysis of three exceptionally well-preserved Late Pleistocenemarine sediment cores from the eastern Caribbean Sea, westernMediterranean Sea and the Indian Ocean. This study presents the first stratigraphical record of heteropods in the Caribbean Sea and extends the known zonation of pteropods in the Mediterranean Sea. Distributions of pteropods, heteropods and planktonic foraminifera are presented with abundance and species richness data, as well as stratigraphical dates inferred from the oxygen isotope stratigraphy, argon-argon dating and biostratigraphy. The findings of this study greatly improve our understanding of holoplanktonic gastropod stratigraphy and ecology. Results reveal that the geographical range of heteropods, thought to be restricted to sub-tropical warm waters,may be much greater, including waters of sub-polar temperature. Heteropods were also found to be surprisingly abundant, potentially representing a more important part of the ocean food web than previously thought. Analysis revealed two species of holoplanktonic gastropod that are previously undescribed and indicate that the pteropod Heliconoides mermuysi (Cahuzac and Janssen 2010), known exclusively from the Moulin de Cabanes (Miocene),may have lived in theCaribbean Sea and Indian Ocean as recently as 4 kyr ago. These findings highlight the urgent need for increased research on holoplanktonic gastropods. The threat that current climate change and ocean acidification poses, particularly to the delicately shelled forms, means that some species may become extinct before they have even been fully ‘discovered’

Teacher Motivation and Learning: Reflective Participation in Professional Learning Communities

As part of the ongoing search for meaningful school reform, many schools have organized themselves into professional learning communities to improve student learning and support teacher learning. Most of the studies on PLCs have focused on their impact on student learning and not on why and how teachers are involved individually and collectively in a meaningful way to support student learning and improved instructional practices through their own professional growth. This qualitative study addresses the motivation of secondary school teachers to engage in their professional learning through their participation in PLCs. The study also sought to explore whether this participation affected teacher learning and their instructional practices. Three research questions guided the study: (a) what motivates teachers to get and remain involved in PLCs; (b) how did teachers believe their participation in PLCs affected teacher learning; (c) did the teachers perceive their participation in PLCs impacted instructional practices. Through one-on-one interviews with teachers, observations of PLCs, artifact collection, and survey responses, data were gathered to learn about how self-motivation influenced teacher involvement in PLC activities. Data collection and analysis were guided and viewed through the lens of Self-Determination Theory, a theory of motivation which focuses on the intrinsic tendencies of people to behave in healthy ways, through their fulfilment of the basic psychological needs of autonomy, competence, and relatedness (Deci & Ryan, 1985; Ryan & Deci, 2000). The major findings of this study identified that while teachers are actively involved in regular PLC activities and are able to demonstrate the essential motivational needs of autonomy, competence, and relatedness, the fact that they are not able to choose their own PLCs nor share a common definition of what a PLC is limits the effectiveness of this process. Autonomy, actualized through the choices that teachers have to influence the activities of their PLC activities, and relatedness, actualized through collaboration and shared work, are present but are dependent upon tenure, department membership, and teacher’s educational philosophy. Also, the lack of a clear sense of how PLCs can support collective inquiry and action research suggests that there will be an inconsistent experience of the benefits of PLCs