The impact of CO2 emissions on 'nuisance' marine species

Anthropogenic CO2 emissions are being taken up from the atmosphere by the oceans, increasing the availability of dissolved inorganic carbon but reducing both the carbonate saturation and pH of seawater. This ocean acidification affects biological processes in a wide range of marine taxa. Here, we assess the likely responses of 'nuisance' species to ocean acidification, meaning those organisms that have undesirable effects from a human perspective. Based on a synthesis of evidence available to date, we predict increased growth and toxicity in harmful algal bloom species, and a significant increase in invasive algae in response to increased CO2 availability. Blooms of stinging jellyfish are also expected to increase since they are highly resilient to acidification. The effects of ocean acidification on invasive molluscs (eg, oyster drills), damaging echinoderms (eg, crown-of-thorns starfish), and a wide range of nuisance taxa will vary depending on species and location. In the USA, for example, the invasive crab Carcinus maenas is resilient to projected increases in CO2 and its impact on marine communities is expected to increase since it feeds on organisms that respond to ocean acidification with weaker defensive traits and lower recruitment. Conversely, the Red King Crab, Paralithodes camtschaticus, is adversely affected by acidification and so is expected to die back in the Barents Sea which it has invaded. Overall, we suspect that there will be an increase in nuisance species, as many have traits that are resilient to the combined warming and acidification caused by rising CO2 levels; region-specific assessments are needed to understand responses of nuisance species in local habitats. Finally, we highlight the need for targeted studies of the effects of global change on particularly harmful marine taxa such as the seaweed Caulerpa taxifolia, the starfish Asterias amurensis, several invasive ascidians, and the lionfish Pterois volitans

Photodissociation and the Morphology of HI in Galaxies

Young massive stars produce Far-UV photons which dissociate the molecular gas on the surfaces of their parent molecular clouds. Of the many dissociation products which result from this ``back-reaction'', atomic hydrogen \HI is one of the easiest to observe through its radio 21-cm hyperfine line emission. In this paper I first review the physics of this process and describe a simplified model which has been developed to permit an approximate computation of the column density of photodissociated \HI which appears on the surfaces of molecular clouds. I then review several features of the \HI morphology of galaxies on a variety of length scales and describe how photodissociation might account for some of these observations. Finally, I discuss several consequences which follow if this view of the origin of HI in galaxies continues to be successful.Comment: 18 pages, 7 figures in 8 files, invited review paper for the conference "Penetrating Bars Through Masks of Cosmic Dust: The Hubble Tuning Fork Strikes a New Note", South Africa, June 2004. Proceedings to be published by Kluwer, eds. D.L. Block, K.C. Freeman, I. Puerari, R. Groess, & E.K. Bloc

Mass mortality and recolonization of pyura stolonifera (heller) on the south coast of South Africa

A mass mortality of the ascidian Pyura stolonifera (red-bait) was recorded along the Tsitsikamma coast of South Africa in May 1991, following the infection of a large proportion of the population with a white microbialgrowth. At nine subtidal red-bait beds, reductions in percentage cover of red-bait were greatest on the crests of reefs (42 ± 17%:1SD) and lowest on the landward edges (17 ± 8%). The test of P. stolonifera appeared to be the main site of the microbial infection. Scanning electron and epifluorescent microscopy revealed much higher numbers of bacteria on the tests of infected individuals (64.3 ± 5.5 × 106·mm-2) compared to healthy ones (5.1 ± 0.1 × 106·mm-2). Fat, curved rod bacteria and thick chains, which accounted for more than 45% of the bacteria on infected red-bait tests, were absent from the tests of healthy red-bait. Standard characterization techniques, coupled with API tests, showed that the isolates from infected red-bait tests belonged exclusively to thegenus Vibrio, whereas isolates from healthy tests included the genera Vibrio, Pseudomonas, Aeromonas and Flavobacterium/Cytophaga. The mass mortality therefore appeared to be associated with the proliferation of large curved rod bacteria of the genus Vibrio. Recolonization by P. stolonifera into areas naturally denuded of red-bait was significantly faster than for experimental plots cleared of all organisms during the mid 1980s. A mean cover of 33 ± 4% was recorded for P. stolonifera after 38 months following natural mortality, whereas it took 71 months to achieve a comparable recovery of 35 ± 20% in experimental plots. Possible reasons for this difference (viz. substratum, recruitment and predation) are explored

We predict a riot: inequity, relative deprivation and collective destruction in the laboratory

Riots are unpredictable and dangerous. Our understanding of the factors that cause riots is based on correlational observations of population data, or post hoc introspection of individuals. To complement these accounts, we developed innovative experimental techniques, investigated the psychological factors of rioting and explored their consequences with agent-based simulations. We created a game, ‘Parklife’, that physically co-present participants played using smartphones. In two teams, participants tapped on their screen to grow trees and flowerbeds on separate but adjacent virtual parks. Participants could also tap to vandalize the other team's park. In some conditions, we surreptitiously introduced inequity between the teams so that one (the disadvantaged team) had to tap more for each reward. The experience of inequity caused the disadvantaged team to engage in more destruction, and to report higher relative deprivation and frustration. Agent-based models suggested that acts of destruction were driven by the interaction between individual level of frustration and the team's behaviour. Our results provide insights into the psychological mechanisms underlying collective action

Linking Maternal Socialization of Emotion Regulation to Adolescents’ Co-rumination With Peers

Mounting research supports that co-rumination, the tendency to seek peer support by engaging in extensive negatively focused discussion, is a risk factor for adolescent psychopathology. It is unclear, though, how this interpersonal tendency develops. Parental responses to adolescents’ negative affect likely shape how youth utilize peer relationships to regulate distress, as they shift to reliance on peer support during this developmental stage. For example, nonsupportive parental responses may fail to instill healthy regulation strategies, resulting in ineffective forms of peer support, such as co-rumination. Conversely, high levels of supportive parental responses to adolescents’ negative affect may motivate youth to also express more negative affect with peers, leading to co-rumination. Eighty-nine healthy adolescents (9-17) and their mothers completed surveys and a support-seeking interaction. Only supportive maternal responses, including maternal affection, were associated with adolescents’ co-rumination. These analyses indicate that some forms of parental support are associated with adolescents’ tendency to co-ruminate

Identifying wellbeing challenges and solutions in the police service using the World Café method

Police work presents risks to mental and physical health for officers and civilian staff. We report a project that involved police employees in identifying wellbeing challenges and potential solutions. We facilitated ‘World Café’ events in which approximately 180 officers and civilian staff participated. Qualitative data were collected and thematically analysed drawing upon the Job Demands-Resources model. We identified themes relating to workload, management practices, occupational health processes, and continuing mental health stigma. Our analyses suggest an environment in which resources are insufficient to meet demands. The resulting pressures may contribute to management behaviours that can impair subordinate wellbeing

The development of path integration: combining estimations of distance and heading

Efficient daily navigation is underpinned by path integration, the mechanism by which we use self-movement information to update our position in space. This process is well-understood in adulthood, but there has been relatively little study of path integration in childhood, leading to an underrepresentation in accounts of navigational development. Previous research has shown that calculation of distance and heading both tend to be less accurate in children as they are in adults, although there have been no studies of the combined calculation of distance and heading that typifies naturalistic path integration. In the present study 5-year-olds and 7-year-olds took part in a triangle-completion task, where they were required to return to the startpoint of a multi-element path using only idiothetic information. Performance was compared to a sample of adult participants, who were found to be more accurate than children on measures of landing error, heading error, and distance error. 7-year-olds were significantly more accurate than 5-year-olds on measures of landing error and heading error, although the difference between groups was much smaller for distance error. All measures were reliably correlated with age, demonstrating a clear development of path integration abilities within the age range tested. Taken together, these data make a strong case for the inclusion of path integration within developmental models of spatial navigational processing

Passive Aeroelastic Tailored Wing Modal Test Using the Fixed Base Correction Method

In modal testing and finite element model correlation, analysts desire modal results using free-free or rigid boundary conditions to ease comparisons of test versus analytical data. It is often expensive both in cost and schedule to build and test with boundary conditions that replicate the free-free or rigid boundaries. Static test fixtures for load testing are often large, heavy, and unyielding, but do not provide adequate boundaries for modal tests because they are dynamically too flexible and often contain natural frequencies within the frequency range of interest of the test article. Dynamic coupling between the test article and test fixture complicates the model updating process because significant effort is required to model the test fixture and boundary conditions in addition to the test article. If there were a way to correct the modal results for fixture coupling, then setups used for other structural testing could be adequate for modal testing. In the case described in this paper, a partial static loads testing setup was used, which allowed significant schedule and cost savings by eliminating a unique setup for a modal test. A fixed base correction technique was investigated during modal testing of a flexible wing cantilevered from part of a static test fixture. The technique was successfully used to measure the wing modes de-coupled from the dynamically active test fixture. The technique is promising for future aircraft applications, but more research is needed