Effects of Elevated Temperature and Carbon Dioxide on the Growth and Survival of Larvae and Juveniles of Three Species of Northwest Atlantic Bivalves

Rising CO2 concentrations and water temperatures this century are likely to have transformative effects on many coastal marine organisms. Here, we compared the responses of two life history stages (larval, juvenile) of three species of calcifying bivalves (Mercenaria mercenaria, Crassostrea virginica, and Argopecten irradians) to temperatures (24 and 28°C) and CO2 concentrations (∼250, 390, and 750 ppm) representative of past, present, and future summer conditions in temperate estuaries. Results demonstrated that increases in temperature and CO2 each significantly depressed survival, development, growth, and lipid synthesis of M. mercenaria and A. irradians larvae and that the effects were additive. Juvenile M. mercenaria and A. irradians were negatively impacted by higher temperatures while C. virginica juveniles were not. C. virginica and A. irradians juveniles were negatively affected by higher CO2 concentrations, while M. mercenaria was not. Larvae were substantially more vulnerable to elevated CO2 than juvenile stages. These findings suggest that current and future increases in temperature and CO2 are likely to have negative consequences for coastal bivalve populations

Engagement Mentoring for 'Disaffected' Youth: A new model of mentoring for social inclusion

This article presents a critical analysis of mentoring for social inclusion. It traces its dramatic international expansion as a tool of education policies in the 1990s, and identifies a new model, 'engagement mentoring', which seeks to re-engage 'disaffected' young people with the formal labour market, and to engage their commitment to dominant interests through shaping their dispositions in line with 'employability'. Mentors are treated as vehicles for these objectives, their dispositions also subject to transformation according to gendered stereotypes of care. The model is illustrated by a case study of engagement mentoring, and feminist readings of Bourdieu and Marx are used to relocate it within the socio-economic context from which it is usually disembedded. The article concludes that engagement mentoring constructs the habitus of both mentor and mentee as a raw material subjected to an emotional labour process

A bioenergetics framework for integrating the effects of multiple stressors: Opening a 'black box' in climate change research

Climate change is already impacting marine ecosystems across a range of scales, from individual physiology, to changes in species interactions and community structure, and ultimately to patterns in geographic distribution. Predicting how marine ecosystems will respond to environmental change is a signifi cant challenge because vulnerability to climatic and non-climatic stressors is highly variable, and depends on an organism\u2019s functional traits, tolerance to stressors, and the environment in which it lives. We present a mechanistic approach based on biophysical and dynamic energy budget models that integrates the cumulative effects of multiple environmental stressors (temperature and food) and stress associated with the presence of predators (the \u201cfear of being eaten\u201d), with the functional traits of an organism. We describe how multiple factors such as feeding time, food availability, and weather can be combined into a few simple metrics and explore how the physiological and behavioral impacts of predation risk can be included in this framework by altering prey feeding time and performance. Importantly, we highlight several critical gaps in our basic understanding of the fundamental mechanisms that drive responses to multiple stressors in natural systems. The framework presented here is, thus, intended to serve as a guide for the formulation of explicit, testable hypotheses and further controlled experimentation