Post-storm geomorphic recovery and resilience of a prograding coastal dune system

Geomorphic resilience is the capacity of a system to recover to pre-disturbance conditions following a perturbation. The 2013/14 Atlantic winter storm period had extensive geomorphological impacts and provides an opportunity to assess coastline resilience. This paper uses high spatio-temporal resolution data to quantify the beach-dune response and subsequent recovery of a prograding coastline following the 5 December 2013 North Sea storm surge. It demonstrates that despite the high water levels and destructive nature of the storm, the beach-dune system recovered sediment rapidly over the first post-storm year. Within four years the dune advance had exceeded the seawards position expected based on long-term coastal trends but had not yet recovered the pre storm foredune profile. Cumulative evidence from numerous European locations suggests one of the stormiest periods on record triggered only a minor disturbance to what appear to be highly resilient beach-dune systems

Structural properties of mobile armors formed at different flow strengths in gravel-bed rivers

Differences in the structure of mobile armors formed at three different flow strengths have been investigated in a laboratory flume. The temporal evolution of the bed surfaces and the properties of the final beds were compared using metrics of surface grain size, microtopography, and bed organization at both grain and mesoscales. Measurements of the bed condition were obtained on nine occasions during each experiment to describe the temporal evolution of the beds. Structured mobile armors formed quickly in each experiment. At the grain scale (1–45 mm; 9 ≤ Ds50 ≤ 17 mm where Ds50 is the median surface particle size), surface complexity decreased and bed roughness increased in response to surface coarsening and the development of the mobile armor. Particles comprising the armor also became flow aligned and developed imbrication. At a larger scale (100–200 mm), the surface developed a mesoscale topography through the development of bed patches with lower and higher elevations. Metrics of mobile armor structure showed remarkable consistency over prolonged periods of near-constant transport, demonstrating for the first time that actively transporting surfaces maintain an equilibrium bed structure. Bed structuring was least developed in the experiments conducted at the lowest flow strength. However, little difference was observed in the structural metrics of the mobile armors generated at higher flows. Although the range of transport rates studied was limited, the results suggest that the structure of mobile armors is insensitive to the formative transport rate except when rates are low (τ* ≈ 0.03 where τ* is the dimensionless shear stress)

Additional file 1: of Portability of the thiolation domain in recombinant pyoverdine non-ribosomal peptide synthetases

Supplementary Table S1. Proteins used for T domain substitutions in this study and percent identity shared between the substituted region and the corresponding sequence from PvdD. (DOCX 19 kb

Additional file 3: of Portability of the thiolation domain in recombinant pyoverdine non-ribosomal peptide synthetases

Supplementary Table S3. Plasmids used in this study. (DOCX 20 kb

Additional file 2: of Portability of the thiolation domain in recombinant pyoverdine non-ribosomal peptide synthetases

Supplementary Table S2. Oligonucleotide primers used in this study. (DOCX 21 kb

Monitoring dune response to the East Coast storm surge of 2013 using laser scanning and SfM photogrammetry

On 5 December 2013, the UK coastline experienced one of the biggest storm surges on record. This storm caused substantial coastal erosion, particularly along the North Sea coast where the southwards travelling surge was heightened by funnelling between the European mainland and the East Coast of England. This paper focuses on a field site located north of Mablethorpe on the Lincolnshire coast (53°21’43”N 0°15’03”E) which has undergone long-term (1891-2010) accretion of, on average, 2m yr-1 (Montreuil and Bullard, 2012). Prior to the 5 December storm event, well-developed coastal foredunes were present with primary foredunes up to 3.5m ODN and secondary (inland) dunes up to 7m high. The storm surge eroded the dunes laterally by up to 20m, creating a vertical scarp face up to 2m high. Provided there are no further storm surges, is expected that the dune system will gradually recover and the scarp will eventually be infilled. The overall aim of this research project is to combine high resolution topographic and environmental data to quantify the rate and nature of post-storm coastal recovery at this site. This paper draws upon this project to highlight how modern geomatic methods can be used for detailed monitoring of coastal phenomena at close range. These methods include both terrestrial laser scanning (TLS) and close range digital photogrammetry, which incorporates the very latest structure from motion (SfM) techniques

Structural properties of mobile armours formed at different flow strengths in gravel-bed rivers

Differences in the structure of mobile armors formed at three different flow strengths have been investigated in a laboratory flume. The temporal evolution of the bed surfaces and the properties of the final beds were compared using metrics of surface grain size, microtopography, and bed organization at both grain and mesoscales. Measurements of the bed condition were obtained on nine occasions during each experiment to describe the temporal evolution of the beds. Structured mobile armors formed quickly in each experiment. At the grain scale (1–45 mm; 9 ≤ Ds50 ≤ 17 mm where Ds50 is the median surface particle size), surface complexity decreased and bed roughness increased in response to surface coarsening and the development of the mobile armor. Particles comprising the armor also became flow aligned and developed imbrication. At a larger scale (100–200 mm), the surface developed a mesoscale topography through the development of bed patches with lower and higher elevations. Metrics of mobile armor structure showed remarkable consistency over prolonged periods of near-constant transport, demonstrating for the first time that actively transporting surfaces maintain an equilibrium bed structure. Bed structuring was least developed in the experiments conducted at the lowest flow strength. However, little difference was observed in the structural metrics of the mobile armors generated at higher flows. Although the range of transport rates studied was limited, the results suggest that the structure of mobile armors is insensitive to the formative transport rate except when rates are low (τ* ≈ 0.03 where τ* is the dimensionless shear stress)