Cycles of coral reef ‘turn-on’, rapid growth and ‘turn-off’ over the past 8,500 years: a context for understanding modern ecological states and trajectories.

This is the author's post-print version of an article published in Global Change Biology, Vol. 17, pp. 76 - 86. Copyright © Wiley-Blackwell 2011. The definitive version is available at www3.interscience.wiley.comHuman activities threaten reef ecosystems globally, forcing ecological change at rates and scales regarded as unprecedented in the Holocene. These changes are so profound that a cessation of reef accretion (reef ‘turn-off’) and net erosion of reef structures is argued by many as the ultimate and imminent trajectory. Here, we use a regional scale reef growth dataset, based on 76 core records (constrained by 211 radiometric dates) from 22 reefs along and across the inner-shelf of the Great Barrier Reef, Australia, to examine the timing of different phases of reef initiation (‘turn-on’), growth and ‘turn-off’ during the Holocene. This dataset delineates two temporally discrete episodes of reef-building over the last 8500 years: the first associated with the Holocene transgression-early highstand period [∼8.5–5.5 k calibrated years bp (cal ybp)]; the second since ∼2.3 k cal ybp. During both periods, reefs accreted rapidly to sea level before entering late evolutionary states – states naturally characterized by reduced coral cover and low accretion potential – and a clear hiatus occurs between these reef-building episodes for which no records of reef initiation exist. These transitions mimic those projected under current environmental disturbance regimes, but have been driven entirely by natural forcing factors. Our results demonstrate that, even through the late Holocene, reef health and growth has fluctuated through cycles independent of anthropogenic forcing. Consequently, degraded reef states cannot de facto be considered to automatically reflect increased anthropogenic stress. Indeed, in many cases degraded or nonaccreting reef communities may reflect past reef growth histories (as dictated by reef growth–sea level interactions) as much as contemporary environmental change. Recognizing when changes in reef condition reflect these natural ‘turn-on’– growth –‘turn-off’ cycles and how they interact with on-going human disturbance is critical for effective coral reef management and for understanding future reef ecological trajectories

Transitions in coral reef accretion rates linked to intrinsic ecological shifts on turbid-zone nearshore reefs

Nearshore coral communities within turbid settings are typically perceived to have limited reef-building capacity. However, several recent studies have reported reef growth over millennial time scales within such environments and have hypothesized that depth-variable community assemblages may act as equally important controls on reef growth as they do in clear-water settings. Here, we explicitly test this idea using a newly compiled chronostratigraphic record (31 cores, 142 radiometric dates) from seven proximal (but discrete) nearshore coral reefs located along the central Great Barrier Reef (Australia). Uniquely, these reefs span distinct stages of geomorphological maturity, as reflected in their elevations below sea level. Integrated age-depth and ecological data sets indicate that contemporary coral assemblage shifts, associated with changing light availability and wave exposure as reefs shallowed, coincided with transitions in accretion rates at equivalent core depths. Reef initiation followed a regional ∼1 m drop in sea level (1200–800 calibrated yr B.P.) which would have lowered the photic floor and exposed new substrate for coral recruitment by winnowing away fine seafloor sediments. We propose that a two-way feedback mechanism exists where past growth history influences current reef morphology and ecology, ultimately driving future reef accumulation and morphological change. These findings provide the first empirical evidence that nearshore reef growth trajectories are intrinsically driven by changes in coral community structure as reefs move toward sea level, a finding of direct significance for predicting the impacts of extrinsically driven ecological change (e.g., coral-algal phase shifts) on reef growth potential within the wider coastal zone on the Great Barrier Reef

Involving your librarian in instruction : or ... how I learned to stop worrying and love my librarian

Presented at 2015 FaCET Conference at UMKC, January 15, 2015Title from PDF, viewed on March 13, 201

Lower Willamette River Model: Boundary Conditions and Model Setup

Water Environment Services of Clackamas County is in the process of planning upgrades on several of its sewage treatment plants which discharge into the Lower Willamette River. The goals of the modeling effort are to: • Gather data to construct a computer simulation model of the Lower Willamette River system including part of the Lower Columbia River and the Willamette River above the Oregon City Falls; Because of the tidal influence in the Lower Willamette River, portions of the Columbia River that might affect the Lower Willamette River water quality were also modeled. Also, a section of the Willamette River above the head of tide, the Oregon City Falls, was modeled because of the lack of good boundary condition data at the Falls. • Ensure that the model accurately represents the system physics and chemistry (flow, temperature, dissolved oxygen and nutrient dynamics); • Use the model to evaluate how to meet various future discharge scenarios for the sewage district. A hydrodynamic and water quality model, CE-QUAL-W2 Version 3 (Wells, 1997), is being applied to model the Willamette-Columbia system. CE-QUAL-W2 is a two dimensional (longitudinal-vertical), laterally averaged, hydrodynamic and water quality model that has been under development by the Corps of Engineers Waterways Experiments Station (Cole and Wells, 2000). In order to model the system, the following data were required: • Willamette and Columbia River flow, water level and water quality data • Tributary inflows and water quality • Meteorological conditions • Bathymetry of the Columbia and Willamette Rivers and several side channels • Point source inflows and water quality characteristics Many local, state and federal agencies have been collecting data in the Lower Willamette and Columbia Rivers. This report summarizes data used in the modeling effort

Does recent research evidence support the hyperpersonal model of online impression management?

This is an accepted manuscript of an article published by Elsevier in Current Opinion in Psychology on 30 May 2020, available online: https://doi.org/10.1016/j.copsyc.2020.05.005 The accepted version of the publication may differ from the final published version.The hyperpersonal model of communication was conceived in the 1990s and has driven much of the research into online impression management. Based on four principal tenets (increased control, asynchronicity of communication, increased physical distance and reallocation of cognitive resources) it has largely received empirical support, especially by research involving text-only communication. This review briefly summarises this research before identifying four areas in which it is not supported by findings: the wider context of online communication, the expanding nature of online platforms to include pictures and video, use of language in online environments, and online self-disclosure. We suggest that the model is modified and updated, or its limitations defined, with respect to this evidence.Published versio

Quantum oscillations in the parent pnictide BaFe2_2As2_2 : itinerant electrons in the reconstructed state

We report quantum oscillation measurements that enable the direct observation of the Fermi surface of the low temperature ground state of \ba122. From these measurements we characterize the low energy excitations, revealing that the Fermi surface is reconstructed in the antiferromagnetic state, but leaving itinerant electrons in its wake. The present measurements are consistent with a conventional band folding picture of the antiferromagnetic ground state, placing important limits on the topology and size of the Fermi surface.Comment: 5 pages, 3 figure

The XMM Cluster Survey: The Dynamical State of XMMXCS J2215.9-1738 at z=1.457

We present new spectroscopic observations of the most distant X-ray selected galaxy cluster currently known, XMMXCS J2215.9-1738 at z=1.457, obtained with the DEIMOS instrument at the W. M. Keck Observatory, and the FORS2 instrument on the ESO Very Large Telescope. Within the cluster virial radius, as estimated from the cluster X-ray properties, we increase the number of known spectroscopic cluster members to 17 objects, and calculate the line of sight velocity dispersion of the cluster to be 580+/-140 km/s. We find mild evidence that the velocity distribution of galaxies within the virial radius deviates from a single Gaussian. We show that the properties of J2215.9-1738 are inconsistent with self-similar evolution of local X-ray scaling relations, finding that the cluster is underluminous given its X-ray temperature, and that the intracluster medium contains ~2-3 times the kinetic energy per unit mass of the cluster galaxies. These results can perhaps be explained if the cluster is observed in the aftermath of an off-axis merger. Alternatively, heating of the intracluster medium through supernovae and/or Active Galactic Nuclei activity, as is required to explain the observed slope of the local X-ray luminosity-temperature relation, may be responsible.Comment: 13 pages, 6 figures, accepted for publication in Ap

Ariel - Volume 10 Number 5

Executive Editors Madalyn Schaefgen David Reich Business Manager David Reich News Editors Medical College Edward Zurad CAHS John Guardiani World Mark Zwanger Features Editors Meg Trexler Jim O\u27Brien Editorials Editor Jeffrey Banyas Photography and Sports Editor Stuart Singer Commons Editor Brenda Peterso