Storm Response of Fluvial Sedimentary Microplastics

Up to 80% of the plastics in the oceans are believed to have been transferred from river networks. Microplastic contamination of river sediments has been found to be pervasive at the global scale and responsive to periods of flooding. However, the physical controls governing the storage, remobilization and pathways of transfer in fluvial sediments are unknown. This means it is not currently possible to determine the risks posed by microplastics retained within the world’s river systems. This problem will be further exacerbated in the future given projected changes to global flood risk and an increased likelihood of fluvial flooding. Using controlled flume experiments we show that the evolution of the sediment bed surface and the flood wave characteristics controls the transition from rivers being ‘sinks’ to ‘sources’ of microplastics under flood conditions. By linking bed surface evolution with microplastic transport characteristics we show that similarities exist between granular transport phenomena and the behavior, and hence predictability, of microplastic entrainment during floods. Our findings are significant as they suggest that microplastic release from sediment beds can be managed by altering the timing and magnitude of releases in flow managed systems. As such it may be possible to remediate or remove legacy microplastics in future

Human-specific phages infecting Enterococcus host strain MW47: Are they reliable microbial source tracking markers?

Aim: The aim of this study was to determine the morphological diversity and environmentalsurvival of human-specific phages infecting Enterococcus faecium host strain MW47, tosupport their use as microbial source tracking (MST) markers. Methods and Results: Twenty phages capable of infecting strain MW47 were propagatedand their morphologies determined using transmission electron microscopy (TEM), whichrevealed that a heterogeneous group of phages was able to infect strain MW47. Three distinctmorphologies from two different families (Myoviridae and Siphoviridae) were observed. Insitu inactivation experiments were subsequently conducted to determine their environmentalpersistence. Conclusion: The findings revealed a statistically significant link between morphology andthe rate of inactivation, with phages belonging to the Myoviridae family demonstrating morerapid inactivation in comparison to those belonging to the Siphoviridae family. Significance and Impact of Study: The results suggest that whilst Enterococcus MW47phages appear to be a potentially valuable MST tools, significant variations in the persistenceof the different phages mean that the approach should be used with caution, as this mayadversely affect the reliability of the approach, especially when comparing MW47 phagelevels or presence across different matrices (e.g. levels in sediments or shellfish). Thishighlights the importance of elucidating the ecological characteristics of newly proposedMST markers before they are used in full-scale MST investigations

Interspecific comparisons of C\u3csub\u3e3\u3c/sub\u3e turfgrass for tennis use: II. Investigaion of ball friction, ball bounce, and associated factors in replicated grass courts

Tennis is played on many different surfaces including natural grass, which plays fast because of low ball bounce (i.e., coefficient of restitution [COR]) and low ball‐to‐surface friction (coefficient of friction [COF]) that increase the pace (ball speed) of tennis. Effects of various C3 turfgrasses on COF and COR have not been investigated. Our objectives were to evaluate eight cultivars of various species randomized within three official size tennis courts: (a) ‘Keeneland’ Kentucky bluegrass (Poa pratensis L., KB), (b) ‘Rubix’ KB, (c) ‘Villa’ velvet bentgrass (Agrostis canina L., VBG), (d) ‘Puritan’ colonial bentgrass (Agrostis capillaris L., CL), (e) ‘007’ creeping bentgrass (Agrostis stolonifera L., CB), (f) fine fescue (Festuca sp., FF) mixture, (g) ‘Karma’ perennial ryegrass (Lolium perenne L, PR), and (h) ‘Wicked’ PR. Friction was measured using a weighted sled and ball bounce (BB) to derive COR was measured using a vertical drop height of 254 cm. Bounce (i.e., COR) to satisfy the International Tennis Federation (ITF) minimum of 50% BB (COR = 0.70) was not observed on any of the species evaluated. Species such as FF and PR were able to achieve BB to satisfy the ITF 80% BB minimum to that observed on smooth concrete. Linear regression indicated that 170g of surface hardness for FF and PR to as much as 200g on KB and higher on BG may be needed to achieve a COR = 0.70. Hemi‐ and lignocellulose cell wall fractions were correlated with COR and COF but exhibited significant and opposite relationships. Achieving higher COF may be a more practical means to slow court pace of notoriously fast grass courts. Future research will be needed to investigate the effects of cultural practices on COF