Drivers and uncertainties of future global marine primary production in marine ecosystem models

Past model studies have projected a global decrease in marine net primary production (NPP) over the 21st century, but these studies focused on the multi-model mean rather than on the large inter-model differences. Here, we analyze model-simulated changes in NPP for the 21st century under IPCC's high-emission scenario RCP8.5. We use a suite of nine coupled carbon–climate Earth system models with embedded marine ecosystem models and focus on the spread between the different models and the underlying reasons. Globally, NPP decreases in five out of the nine models over the course of the 21st century, while three show no significant trend and one even simulates an increase. The largest model spread occurs in the low latitudes (between 30° S and 30° N), with individual models simulating relative changes between −25 and +40 %. Of the seven models diagnosing a net decrease in NPP in the low latitudes, only three simulate this to be a consequence of the classical interpretation, i.e., a stronger nutrient limitation due to increased stratification leading to reduced phytoplankton growth. In the other four, warming-induced increases in phytoplankton growth outbalance the stronger nutrient limitation. However, temperature-driven increases in grazing and other loss processes cause a net decrease in phytoplankton biomass and reduce NPP despite higher growth rates. One model projects a strong increase in NPP in the low latitudes, caused by an intensification of the microbial loop, while NPP in the remaining model changes by less than 0.5 %. While models consistently project increases NPP in the Southern Ocean, the regional inter-model range is also very substantial. In most models, this increase in NPP is driven by temperature, but it is also modulated by changes in light, macronutrients and iron as well as grazing. Overall, current projections of future changes in global marine NPP are subject to large uncertainties and necessitate a dedicated and sustained effort to improve the models and the concepts and data that guide their developmen

Runs of homozygosity in killer whale genomes provide a global record of demographic histories

Runs of homozygosity (ROH) occur when offspring inherit haplotypes that are identical by descent from each parent. Length distributions of ROH are informative about population history; specifically, the probability of inbreeding mediated by mating system and/or population demography. Here, we investigated whether variation in killer whale (Orcinus orca) demographic history is reflected in genome-wide heterozygosity and ROH length distributions, using a global data set of 26 genomes representative of geographic and ecotypic variation in this species, and two F1 admixed individuals with Pacific-Atlantic parentage. We first reconstructed demographic history for each population as changes in effective population size through time using the pairwise sequential Markovian coalescent (PSMC) method. We found a subset of populations declined in effective population size during the Late Pleistocene, while others had more stable demography. Genomes inferred to have undergone ancestral declines in effective population size, were autozygous at hundreds of short ROH (1.5 Mb) were found in low latitude populations, and populations of known conservation concern. These include a Scottish killer whale, for which 37.8% of the autosomes were comprised of ROH >1.5 Mb in length. The fate of this population, in which only two adult males have been sighted in the past five years, and zero fecundity over the last two decades, may be inextricably linked to its demographic history and consequential inbreeding depression

Entrepreneurs’ mental health and well-being:A review and research agenda

Interest in entrepreneurs’ mental health and well-being (MWB) is growing in recognition of the role of MWB in entrepreneurs’ decision making, motivation, and action. Yet relevant knowledge is dispersed across disciplines, which makes what we currently understand about entrepreneurs’ MWB unclear. In this systematic review I integrate insights from 144 empirical studies. These studies show that research is focused on three research questions: (1) Do different types of entrepreneurs differ in their MWB? What are the (2) antecedents and (3) consequences of entrepreneurs’ MWB? The review systematizes evidence on known antecedents and consequences of entrepreneurs’ MWB but also reveals overlooked and undertheorized sources and outcomes of entrepreneurs’ MWB. The review provides a mapping and framework that advance research on entrepreneurs’ MWB and help to position entrepreneurs’ MWB more centrally in management and entrepreneurship research. It calls for researchers to go beyond applying models developed for employees to understand entrepreneurs. Instead, the findings point the way to developing a dedicated theory of entrepreneurial work and MWB that is dynamic, socialized, and open to considering context and acknowledges variability and fluidity across entrepreneurs’ life domains, as well as the centrality of work for entrepreneurs’ identity

Can empathy lead to emotional exhaustion in teachers? The mediating role of emotional labor

Objectives: The present study was designed to examine the links between empathy, emotional labor (both surface and deep acting), and emotional exhaustion as well as determine if emotional labor mediates the relationship between empathy and emotional exhaustion in teachers. It was assumed that emotional labor can take two opposite directions (positive mood induction and negative mood induction). Thus, the additional aim of the study was to analyze the mediating role of mood regulation strategies in the relationship between empathy and emotional exhaustion. Materials and Methods: A sample of 168 teachers from Łódź and its surroundings completed a set of questionnaires: Emotional Labor Scale; Mood Regulation Scales, Maslach Burnout Inventory, and Empathic Sensitivity Scale. Results: The results provided mixed support for the hypotheses indicating that both types of emotional labor, negative mood induction and emotional exhaustion were positively intercorrelated. Moreover, deep acting was a significant mediator in the relationship between empathy and emotional exhaustion. The analyzed link was also mediated by negative mood induction, whereas positive mood induction did not emerge as a significant mediator. Conclusions: The study provided insight into the role of empathy and emotional labor in the development of teacher burnout. It also confirmed that deep acting and negative mood induction mediate the relationship between empathy and emotional exhaustion in teachers

fMRI BOLD signal changes in elite swimmers while viewing videos of personal failure

Athletes who fail are susceptible to negative affect (NA) and impaired future performance. Functional magnetic resonance imaging (fMRI) studies have identified prefrontal, anterior cingulate, and limbic activations following negative mood provocation. Little is known about the neural correlates of negative self-reference (SR), especially in athletes. Even less is known about the neural correlates of the effects of cognitive intervention (CI) in modifying negative SR and NA in this population. In an fMRI study, 13 athletes watched a video of their own career-threatening defeat in two controlled blocks. Between fMRI blocks, they received a 20-min CI designed to assist in event reappraisal and planning for future performance. Relative increases post-CI were seen in premotor (BA6) and sensorimotor (BA4/1) cortices. Correlated with mood ratings, relatively higher pre-CI levels were seen in the ventromedial prefrontal cortex, the right dorsomedial prefrontal cortex (PFC; BA10), the right dorsolateral PFC (BA45), the anterior cingulate, and the right parahippocampus. CI may counteract the detrimental effects of NA and negative SR on premotor and motor activity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83878/1/fMRI-BOLD-signal-changes-in-elite-swimmers-while-viewing-videos-of-personal-failure.pd

The mechanisms of North Atlantic CO₂ uptake in a large Earth System Model ensemble

The oceans currently take up around a quarter of the carbon dioxide (CO2) emitted by human activity. While stored in the ocean, this CO2 is not influencing Earth's radiation budget; the ocean CO2 sink therefore plays an important role in mitigating global warming. CO2 uptake by the oceans is heterogeneous, with the subpolar North Atlantic being the strongest CO2 sink region. Observations over the last 2 decades have indicated that CO2 uptake by the subpolar North Atlantic sink can vary rapidly. Given the importance of this sink and its apparent variability, it is critical that we understand the mechanisms behind its operation. Here we explore the combined natural and anthropogenic subpolar North Atlantic CO2 uptake across a large ensemble of Earth System Model simulations, and find that models show a peak in sink strength around the middle of the century after which CO2 uptake begins to decline. We identify different drivers of change on interannual and multidecadal timescales. Short-term variability appears to be driven by fluctuations in regional seawater temperature and alkalinity, whereas the longer-term evolution throughout the coming century is largely occurring through a counterintuitive response to rising atmospheric CO2 concentrations. At high atmospheric CO2 concentrations the contrasting Revelle factors between the low latitude water and the subpolar gyre, combined with the transport of surface waters from the low latitudes to the subpolar gyre, means that the subpolar CO2 uptake capacity is largely satisfied from its southern boundary rather than through air–sea CO2 flux. Our findings indicate that: (i) we can explain the mechanisms of subpolar North Atlantic CO2 uptake variability across a broad range of Earth System Models; (ii) a focus on understanding the mechanisms behind contemporary variability may not directly tell us about how the sink will change in the future; (iii) to identify long-term change in the North Atlantic CO2 sink we should focus observational resources on monitoring lower latitude as well as the subpolar seawater CO2; (iv) recent observations of a weakening subpolar North Atlantic CO2 sink may suggest that the sink strength has peaked and is in long-term decline

Neonatal nonhandling and in utero prenatal stress reduce the density of NADPH-diaphorase-reactive neurons in the fascia dentata and Ammon's horn of rats.

The density of nitric oxide (NO)-producing neurons in the fascia dentata and Ammon's horn was assessed in 6-month-old male rats using NADPH-diaphorase (NADPH-d) histochemistry. Two separate experiments investigated whether (1) the complete absence of neonatal handling or (2) the administration of periodic prenatal stress could affect the expression and distribution of NADPH-d reactivity in the hippocampus, when compared with rats raised in normal standard laboratory conditions. Experiment 1 demonstrated that adult rats that received no handling during neonatal development (from birth to postnatal day 22) showed a very substantial reduction in NADPH-d-positive neurons per unit area throughout the entire hippocampus when compared with rats that received regular daily handling in this period. Quantitative analysis further revealed that this effect was significantly more pronounced in Ammon's horn than in the fascia dentata, and within Ammon's horn the dorsal region was selectively more affected. Experiment 2 showed that prenatal stress, which involved the administration of daily restraint stress to pregnant dams throughout the gestation period, also led to a reduction in NADPH-d reactivity in the hippocampus of the offspring of these dam when they reached adulthood. The present results suggest that behavioral manipulations in the early neonatal or prenatal period can significantly alter the neurodevelopment of the hippocampal NO system and these changes might be related to some of the behavioral abnormalities that emerge later in adulthood

Tectonic, Oceanographic, and Climatic Controls on the Cretaceous-Cenozoic Sedimentary Record of the Australian-Antarctic Basin

Understanding the patterns and characteristics of sedimentary deposits on the conjugate Australian-Antarctic margins is critical to reveal the Cretaceous-Cenozoic tectonic, oceanographic, and climatic conditions in the basin. However, unraveling its evolution has remained difficult due to the different seismic stratigraphic interpretations on each margin and sparse drill sites. Here, for the first time, we collate all available seismic reflection profiles on both margins and use newly available offshore drilling data to develop a consistent seismic stratigraphic framework across the Australian-Antarctic basins. We find sedimentation patterns similar in structure and thickness, prior to the onset of Antarctic glaciation, enabling the basinwide correlation of four major sedimentary units and their depositional history. We interpret that during the warm and humid Late Cretaceous (~83–65 Ma), large onshore river systems on both Australia and Antarctica resulted in deltaic sediment deposition offshore. We interpret that the onset of clockwise bottom currents during the early Paleogene (~58–48 Ma) formed prominent sediment drift deposits along both continental rises. We suggest that these currents strengthened and progressed farther east through the Eocene. Coevally, global cooling (<48 Ma) and progressive aridification led to a large-scale decrease in sediment input from both continents. Two major Eocene hiatuses recovered by the Integrated Ocean Discovery Program site U1356A at the Antarctic continental slope likely formed during this preglacial phase of low sedimentation and strong bottom currents. Our results can be used to constrain future paleo-oceanographic modeling of this region and aid the understanding of the oceanographic changes accompanying the transition from a greenhouse to icehouse world