The importance of topography in the occurrence of glacial valleys in Belarus

The relief of the ice-sheet bed predetermines the location of the valleys both in vast regions and in local, relatively limited areas. The influence of the relief in a large region on the formation of valleys occurs in lowland, more dissected northern and western regions of Belarus. Here, the bedrock relief plays a key role in appearance the hollow-like Vidzovsky, Polotsk and Surazh glacial erosion depressions and in isolation of the elevations separating them. The distribution of these largest forms of glacial erosion is associated with the regional picture of the glacial ice flow in topographic depressions, increased erosion of the ice bed, which developed under the glacial streams and lobes of the Scandinavian ice sheet. The degree and character of the relief dissection, the size, surface slope and orientation of the depressions, river paleo-valleys, elevations, and escarps had a leading role in the location of valleys in local, relatively limited areas. Their significance for the formation of valleys was to determine the local picture of the glacial flow and the areas where stresses were concentrated at the bed and glacial erosion intensified. The formation of tunnel valleys was possible in depressions and in the dissected relief of the glacial bed, which contributed to the accumulation of meltwater, the formation of subglacial lakes, as well as the concentration of meltwater in the subglacial channels.

A better appreciation of glacial floodplain morphodynamics reveals that disturbances are not spatially homogenous: implications for biofilm development

<p>Recent decades have seen worldwide glacier retreat that has resulted in a significant increase in the spatial extent of proglacial margins. Such margins, by switching from being ice-covered to light-exposed, are open to potential colonization by new organisms. However, ecological succession in glacial forefields may be slowed or even precluded by the highly unstable nature of these environments and habitability might be highly variable both in time and in space.</p><p>Discharge-related processes are likely to dominate forefields, in particular during the melt season. Discharge defines the shear forces acting upon the streambed, and ultimately bed and suspended loads and the rate of morphodynamic change through the floodplains. Evidence suggests that during the melt season glacial streams continuously rework their accommodation spaces by erosion and deposition processes, resulting in low rates of environmental stability. This means that benthic organisms, such as biofilms, inhabiting those streams may continuously be under pressure.</p><p>Biofilms are surface-attached communities composed of microorganisms, they are at the base of instream food webs, and they are involved in multiple ecosystem processes. Nevertheless, their surface-attached nature leads them to be easily removed from their lodging substrates by hydraulic disturbances. Because disturbance-dominated regimes exist during the melt season in glacial streams, it should be expected that biofilms might not be able to develop or persist during the melt season. A core idea in glacial stream ecology is that biomass, either of biofilms but also of macrozoobenthos, increases by moving away from the glacial snout, but also that it fluctuates during the year and reaches its highest mass during windows of opportunity (i.e., spring and fall). Even though this paradigm might hold, it does not fully capture the complexity of glacial floodplain morphodynamics, and the possibility that some stable zones exist even in summer. This explains why biofilms are able to develop in summer, and why well-developed biofilms can be found even close to the glacier snouts during the melt season.</p><p>In this paper, we present the first insights about the reasons why biofilms can develop in glacial floodplains during the melt season and, in particular, how important stable zones are for biofilm development. Through classical morphological and morphodynamic analysis, we seek to demonstrate that disturbances are not spatially homogenous, and geomorphic processes can shape the environment creating hot spot for biota. In this view, we argue that floodplain terraces, either permanent or temporary, play a crucial role in defining where biofilms – and consequently organisms that feed on them – settle, develop and grow.</p>

Cricotopus (s. str.) latellai sp. n., a new rheophilic species of the tremulus-group from the Italian and French Maritime Alps (Diptera: Chironomidae)

Cricotopus (Cricotopus) latellai sp. n. is described and diagnosed based on material comprising male and female pharate adults, pupal exuviae and larvae recently collected in some glacial streams in both the Italian and French Maritime Alps. Taxonomic notes provided in this paper include: description of C. latellai sp. n. as male and female adults, pupal exuviae and last instar larvae. The diagnosis of the Cricotopus tremulus-group is supplemented with additional characters in the male adult and pupal exuviae. Cricotopus latellai sp. n. keys near C. mantetanus Moubayed-Breil, 2016 and C. storozhenkoi Makarchenko & Makarchenko, 2016. Geographical distribution of C. latellai sp. n. is currently restricted to the Italian and French Maritime Alps. It belongs to the Tyrrhenian community of glacial relic species, which are considered to be indicators of climate change in this biogeographical region. Remarks, taxonomic position, and ecology of the new described species are given.

Advance Fast Water Spill Response Tactics

ABSTRACT Alaska rivers and streams present many distinct challenges for spill response due to the remoteness of the environment of the 800 miles of Trans Alaska Pipeline traverses through Alaska. The Glacial and non Glacial streams and rivers seasonally produce current velocities that vary from 2 ft/s to 12 ft/s for operating conditions to respond to the event of a spill that may potentially enter them. Alyeska Pipeline Service Company has 5 different programs that the Emergency Preparedness Compliance Team actively employs. These Programs have contributed to developing innovative advanced fast water booming containment and recovery tactical responses to potential oil spill scenarios. These programs are the Pipeline C-Plan Equipment & PM Committee, Pipeline Training Academy, Exercise and Lessons Learned, Vessel Operating Committee, and LPS Safety Programs that affect Oil Spill Response. These programs have a strong focus on safety. The development of faster boom has increased the capability of booming extremely fast water that was not achievable in the past. The further development of midstream anchoring systems and shoreline anchor systems has advanced the capabilities of booming rivers that were previously not achievable. There are difficult challenges of fast water river systems that do not present slow or back water eddies for containment and recovery. They have now become achievable using partial deployment of portable light weight dams across a small segment of the river profile to produce these opportunities for recovery. Helicopter slinging operations using the Harbour Buster System to remote rivers of Alaska have also proven to be effective and tested for response capabilities. The techniques used are equally applicable to all regions of the world and have been presented to a network of OSRO's. The presentation will present the development of empirical data gathered from different river velocities and conditions. Using this research data will help predict and calculate boom requirements in each unique condition for Operations and Task Forces in tactical response. Profiling river hydrology is essential to the success of containment and recovery. The profiling assessment will identify key elements for operational and tactic decisions in choosing the optimal location for making diversion and containment boom sets for recover efforts for spill response.