Big data opportunities and challenges for assessing multiple stressors across scales in aquatic ecosystems

Aquatic ecosystems are under threat from multiple stressors, which vary in distribution and intensity across temporal and spatial scales. Monitoring and assessment of these ecosystems have historically focussed on collection of physical and chemical information and increasingly include associated observations on biological condition. However, ecosystem assessment is often lacking because the scale and quality of biological observations frequently fail to match those available from physical and chemical measurements. The advent of high-performance computing, coupled with new earth observation platforms, has accelerated the adoption of molecular and remote sensing tools in ecosystem assessment. To assess how emerging science and tools can be applied to study multiple stressors on a large (ecosystem) scale and to facilitate greater integration of approaches among different scientific disciplines, a workshop was held on 10-12 September 2014 at the Sydney Institute of Marine Sciences, Australia. Here we introduce a conceptual framework for assessing multiple stressors across ecosystems using emerging sources of big data and critique a range of available big-data types that could support models for multiple stressors. We define big data as any set or series of data, which is either so large or complex, it becomes difficult to analyse using traditional data analysis methods

The effects of radiation on sperm swimming behavior depend on plasma oxidative status in the barn swallow (Hirundo rustica)

Sperm are highly susceptible to reactive oxygen species (ROS) that can damage sperm DNA and structure, resulting in reduced fertilizing capacity. Exposure to radioactive contamination can also impair sperm swimming behavior and fertilizing ability, both through a reduction of sperm DNA integrity and via an increased generation of reactive oxygen species (ROS). However, the relationship between individual oxidative status and sperm swimming behavior has never been investigated in any wild population of animals exposed to radioactive contamination. We studied the motility of sperm collected from barn swallows, Hirundo rustica, breeding under different levels of radioactive contamination following the Chernobyl accident in 1986, in relation to individual oxidative status. We tested the hypothesis that the degree of impairment of sperm swimming behavior by radioactive contamination depended on plasma antioxidant capacity, the level of reactive oxygen metabolites (ROMs) and oxidative stress (sensu Costantini et al. 2006), a better oxidative status being associated with higher sperm motility. Sperm behavior parameters were subjected to principal component (PC) analysis, which extracted four PCs explaining 86% of the variance in sperm motility. PC2, representing sperm with high track velocity and ample lateral head displacement, was significantly predicted by the interaction between radiation level and either oxidative damage or oxidative stress. Contrary to our predictions, the highest values of PC2 were associated with relatively high radiation levels, particularly for high levels of either ROMs or oxidative stress. In addition, there was a tendency for values of PC3 (representing the percent of motile sperm) and PC4 (representing slow sperm with high beat cross frequency) to depend on the interaction between radiation level and total plasma antioxidant protection. Our results confirm the importance of oxidative status in determining the genetic and physiological outcome of exposure to radioactive contamination, complementing previous studies relating sperm abnormality to circulating levels of specific antioxidants. Our results also complement previous evidence that oxidative damage of sperm was negatively related to sperm motility, thus indicating a possible trade-off in quenching pro-oxidant compounds in the plasma and the seminal fluid

Acute cholangitis - Predictive factors for emergency ERCP

Background: Acute cholangitis varies in severity from a mild form to severe cases which require urgent biliary decompression. Aim: This study was undertaken in order to develop a prognostic scoring system that can be used to predict which patients are likely to require emergency endoscopic retrograde cholangiopancreatogram (ERCP) upon admission. Methods: This is a prospective study of 142 consecutive patients with acute cholangitis. Emergency ERCP was performed in patients who did not respond to medical therapy. Results: Thirty-one patients (21.8%) required emergency ERCP. A maximum heart rate of more than 100/min, albumin of less than 30 g/L, bilirubin of more than 50 μmol/L and prothrombin time of more than 14 s on admission were associated with failure of medical treatment and the need for emergency ERCP (P = 0.001, < 0.001, 0.006 and 0.004, respectively). By using these four factors in a scoring system, 50.7% of those with a score of one or more required emergency ERCP compared with 1.5% of those with none of the four risk factors (P < 0.001). This scoring system has a sensitivity of 96.8% and a specificity of 59.6%. Conclusions: As patients with severe acute cholangitis show a higher mortality, we recommend that emergency ERCP be performed in patients with one or more of the four prognostic factors.link_to_OA_fulltex