Bioturbation in a Declining Oxygen Environment, in situ Observations from Wormcam

Bioturbation, the displacement and mixing of sediment particles by fauna or flora, facilitates life supporting processes by increasing the quality of marine sediments. In the marine environment bioturbation is primarily mediated by infaunal organisms, which are susceptible to perturbations in their surrounding environment due to their sedentary life history traits. Of particular concern is hypoxia, dissolved oxygen (DO) concentrations ≤2.8 mg l−1, a prevalent and persistent problem that affects both pelagic and benthic fauna. A benthic observing system (Wormcam) consisting of a buoy, telemetering electronics, sediment profile camera, and water quality datasonde was developed and deployed in the Rappahannock River, VA, USA, in an area known to experience seasonal hypoxia from early spring to late fall. Wormcam transmitted a time series of in situ images and water quality data, to a website via wireless internet modem, for 5 months spanning normoxic and hypoxic periods. Hypoxia was found to significantly reduce bioturbation through reductions in burrow lengths, burrow production, and burrowing depth. Although infaunal activity was greatly reduced during hypoxic and near anoxic conditions, some individuals remained active. Low concentrations of DO in the water column limited bioturbation by infaunal burrowers and likely reduced redox cycling between aerobic and anaerobic states. This study emphasizes the importance of in situ observations for understanding how components of an ecosystem respond to hypoxia

Mapping the Relationship Among Political Ideology, CSR Mindset, and CSR Strategy: A Contingency Perspective Applied to Chinese Managers

The literature on antecedents of corporate social responsibility (CSR) strategies of firms has been predominately content driven. Informed by the managerial sense-making process perspective, we develop a contingency theoretical framework explaining how political ideology of managers affects the choice of CSR strategy for their firms through their CSR mindset. We also explain to what extent the outcome of this process is shaped by the firm’s internal institutional arrangements and external factors impacting on the firm. We develop and test several hypotheses using data collected from 129 Chinese managers. The results show that managers with a stronger socialist ideology are likely to develop a mindset favouring CSR, which induces the adoption of a proactive CSR strategy. The CSR mindset mediates the link between socialist ideology and CSR strategy. The strength of the relationship between the CSR mindset and the choice of CSR strategy is moderated by customer response to CSR, industry competition, the role of government, and CSR-related managerial incentives

Geological, Physical and Chemical Foundations

Modern tidal flats are coastal geomorphological features with a recentgeologic history (Holocene period, 10,000 YBP) that are found globally, underdifferent climatic, hydrodynamic and sedimentological regimes. They are primarilycharacterized by fine-grained sedimentary deposits (silt and clay) that present uniquephysical and chemical properties, in comparison to other sediment types. The input ofsediments to mudflats can be either riverine, from offshore, and/or from the erosion ofcoastal sedimentary deposits. Tides and tidal currents are the dominant hydrodynamicforces shaping mudflats, with wave action playing a secondary role. Theoccurrence of intermittent or temporary flooding and the presence of variable redox(oxidation-reduction) conditions are typical features of mudflat sediments. Thetemporally and spatially variable changes from aerobic, oxidized states of mudflatsediment and porewater to anaerobic, reduced states drive particular redox reactionsthat govern the characteristic chemical processes and biogeochemical functioningthat distinguish mudflats from other coastal settings. Mudflat sediments are not inert;the high surface area:volume ratio of fine-grained sediment particles offers a vast andstructurally-complex landscape for colonization by microbes that rely on surfaceadhesionprocesses. Photosynthetic microalgae belonging to several taxonomicgroups (collectively known as microphytobenthos MPB) are the dominant microorganismsgrowing in association with sedimentary particles, and forming a biofilmlayer on top. In addition to physical forces, living benthic communities modifysediment properties as part of their normal physiology (micro- and macro-biota)and feeding, movement, and burrowing activity (meio- and macrofauna), especiallyin relation to stabilization and destabilization processes. These may ultimately havemarked effects on sediment stability and geomorphology. The interplay between suchbiological processes and sediments in mudflats is currently an active field of research.Fil: Pan, Jeronimo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Pratolongo, Paula Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Cuadrado, Diana Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentin