Impacts of small-scale faults on continental to coastal plain deposition: Evidence from the Realgrunnen Subgroup in the Goliat field, southwest Barents Sea, Norway

Vessel generated waves can impact shoreline stability and habitat structure in many waterways. Sheltered regions, such as coastal plain saltmarshes, support fragile ecosystems and can be particularly vulnerable to the effects of unregulated vessel operations. Instruments for measuring currents and sediment concentration were deployed in a coastal plain saltmarsh to examine the small-scale physical characteristics of the vessel wake generated by recreational craft typical of this environment. The response to vessel wake varied sharply depending upon the stage of the tide. At low tide, waves breaking on the exposed bank produced high concentrations of suspended material that were transported offshore through turbulent diffusion. When the water elevation exceeded the toe of the marsh scarp, the concentration and turbulent kinetic energy exhibited less of a statistically significant variation in response to vessel passage. For the most energetic flows, the vessel orbital velocities were dwarfed by turbulent fluctuations generated by the sheared tidal boundary layer. While further research is required, preliminary findings indicate that the dissipation of vessel wake energy may stimulate or enhance shear generated turbulence if the characteristic wave period is similar to the characteristic time scale of the energy containing eddies.

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Extreme small-scale wind episodes over the Barents Sea: When, where and why?

Climate Dynamics ◽

10.1007/s00382-014-2462-4 ◽

2015 ◽

Vol 45 (7-8) ◽

pp. 2137-2150 ◽

Cited By ~ 8

Author(s):

Erik W. Kolstad

Keyword(s):

Barents Sea ◽

Small Scale ◽

The Barents Sea

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Analysis of tidal sea-ice movement using a drifting ice beacon array in the Barents Sea

10.5194/egusphere-egu2020-7544 ◽

2020 ◽

Author(s):

Amey Vasulkar ◽

Lars Kaleschke ◽

Martin Verlaan ◽

Cornelis Slobbe

Keyword(s):

Sea Ice ◽

Barents Sea ◽

Global Ocean ◽

Series Data ◽

Small Scale ◽

Ice Thickness ◽

Drag Coefficients ◽

The Barents Sea ◽

Ice Drift ◽

Drifting Ice

In an experiment to validate an ice forecast and route optimization system, an array of 15 ice drift beacons/buoys were deployed between Edge&#248;ya and Kong Karls Land in the east of Svalbard to measure the sea ice movement. These beacons recorded data at a sampling frequency of 15 minutes in the duration from March 2014 to May 2014 with different start and end dates based on their life. The particularly short time step captures the small scale effect of tides on the drifting ice. In this region of the Barents Sea, the frequency of the inertial motion is very close to the M2 tidal frequency. Hence, it is not possible to extract the tidal motion from the time series data of the buoys by using a Fourier analysis. It is also likely that these effects will interact. Instead, we develop a physics-based free drift ice model that can simulate the drift at all tidal and other frequencies.The model is forced by winds obtained from the ERA5 Reanalysis dataset of ECMWF and ocean currents obtained from the Global Ocean Analysis product of CMEMS. Due to the effect of tides, the model is also forced by the tides obtained from the Global Tide and Surge Model (GTSM v3.0) which is built upon Delft3D-FM unstructured mesh code. This free drift model is validated against 8 of the 15 beacon trajectories. The model along with the observed data can be then be used to obtain insights on the relationship between the sea ice velocities and the tides. This will be particularly useful to obtain the effect of ice drift on tides in tidal models.The model uncertainty is mainly due to oceanic and atmospheric drag coefficients, Cdw and Cda, respectively, and the sea ice thickness, hi. This study also focuses on optimizing the ratio of drag coefficients (Cdw/Cda) for the different beacon trajectories while varying the ice thickness between 0.1 m - 1.5 m and the ice-air drag coefficient between (0.5-2.5)x10-3. This ratio facilitates the evaluation of the frictional drag between the ice-water interface and thus, helps in determining the effect of ice on tides in tidal models.

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Map showing distribution of small-scale deformation structures in a part of the upper coastal plain of South Carolina and adjacent Georgia

10.3133/mf1538 ◽

1983 ◽

Keyword(s):

South Carolina ◽

Coastal Plain ◽

Small Scale ◽

Deformation Structures

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RoxAnn bottom classification system, sidescan sonar and video-sledge: spatial resolution and their use in assessing trawling impacts

ICES Journal of Marine Science ◽

10.1016/j.icesjms.2003.10.001 ◽

2004 ◽

Vol 61 (1) ◽

pp. 53-63 ◽

Cited By ~ 31

Author(s):

Odd-Børre Humborstad ◽

Leif Nøttestad ◽

Svein Løkkeborg ◽

Hans Tore Rapp

Keyword(s):

Spatial Resolution ◽

Classification System ◽

Barents Sea ◽

Marine Protected Area ◽

Acoustic Properties ◽

Sidescan Sonar ◽

Small Scale ◽

Seabed Classification ◽

Physical Effects ◽

Bottom Classification

Abstract Three complementary seabed characterization tools with different spatial resolution were used to locate a research site and to assess physical effects of experimental otter trawling in the Barents Sea: an acoustic seabed classification system (RoxAnn), sidescan sonar and a video-sledge. The marine protected area (MPA) around Bear Island was chosen as it offered unfished reference sites. The area was topographically complex which resulted in certain challenges for choice of the experimental site due to the requirements of representativity and homogeneity and suitable sampling substrate. Systematic waylines with RoxAnn gave broad-scale patterns of bottom conditions, the more informative sidescan revealed topographic reliefs, whilst detailed information on sediment composition and small-scale seabed features was provided by the video-sledge. Accurate positioning of towed gears (trawl, sidescan and video-sledge) ensured unbiased data acquisition. Trawl doors and rockhopper gear created furrows that were visible by sidescan sonar and video. Intensive trawling also caused changes in the acoustic properties by increasing roughness and decreasing hardness. Results are consistent with a possible resuspension of the sediment and a homogenizing effect from the trawl doors and ground gear ploughing the area. The suitability and advantages of using spatially overlapping tools in trawl impact studies are discussed.

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Groundwater flow modelling to assist dryland salinity management of a coastal plain of southern Australia

Soil Research ◽

10.1071/s96101 ◽

1997 ◽

Vol 35 (4) ◽

pp. 669 ◽

Cited By ~ 6

Author(s):

Paul Pavelic ◽

Kumar A. Narayan ◽

Peter J. Dillon

Keyword(s):

Groundwater Flow ◽

Groundwater Recharge ◽

Coastal Plain ◽

Small Scale ◽

Management Options ◽

Aquifer System ◽

Groundwater Levels ◽

Flow Modelling ◽

Groundwater Flow Modelling ◽

The Impact

Groundwater flow modelling has been undertaken for an area of 10 500 ha within the regional unconfined aquifer system of a coastal plain of southern Australia, in the vicinity of the town of Cooke Plains, to predict the impact of various land management options (including recharge reduction and discharge enhancement) on the extent of land salinisation caused by shallow saline watertables. The model was calibrated against field data collected over 6 years. Sensitivity analysis was performed to assess the influence of mesh size, boundary conditions, and aquifer parameters, and particularly rates of recharge and evaporative discharge, on groundwater levels. These were varied until the model was shown to be capable of simulating seasonal trends and regional and local flow patterns. The model was then used to predict the impact of the management options on groundwater levels. The results showed that continuing current annual crop–pasture rotations will result in watertable rises of approximately 0·2 m in 20 years (significant in this setting), with a further 50 ha of land salinised. A reduction in the rates of groundwater recharge through the establishment of high water-use perennial pastures (e.g. lucerne) showed the most promise for controlling groundwater levels. For example, a reduction in recharge by 90% would result in watertable declines of 0·6–1·0 m within 5–10 years, with the return to productivity of 180 ha of saline land. Small-scale (say <100 ha) efforts to reduce recharge were found to have no significant impact on groundwater levels. Enhanced groundwater discharge such as pumping from a windmill was found to be non-viable due to the relatively high aquifer transmissivity and specific yield. The modelling approach has enabled a relatively small area within a regional aquifer system to be modelled for a finite time (20 years) and has shown that extension of the boundaries of the model would not have altered the predicted outcomes. Furthermore, the analysis of sensitivity to cell size in an undulating landscape where net recharge areas can become net discharge areas with only small increases in groundwater level is novel, and has helped to build confidence in the model. Modelling has demonstrated that dryland salinisation can be controlled by reducing groundwater recharge over substantial tracts of land, and is not dependent on recharge reduction over an extensive area upgradient, at least over the next 20 years.

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Basin history deduced from subtle changes in fluvial style: a study of distal alluvium from the Devonian of southwest Ireland

Transactions of the Royal Society of Edinburgh Earth Sciences ◽

10.1017/s0263593300003357 ◽

1992 ◽

Vol 83 (4) ◽

pp. 655-667 ◽

Cited By ~ 6

Author(s):

John R. Graham ◽

Andrea James ◽

Kenneth J. Russell

Keyword(s):

Coastal Plain ◽

Depositional Environments ◽

Upper Devonian ◽

Small Scale ◽

Basin Evolution ◽

Progressive Reduction ◽

Red Sandstone ◽

Extensional Basin ◽

Subsidence Rate ◽

Ephemeral Channels

AbstractTwo detailed sections through 4 km of distal alluvium of the Upper Devonian Old Red Sandstone in the Munster Basin, southern Ireland, display a limited number of lithofacies. There is little ordering of these lithofacies on a small scale but changes in the proportions of lithofacies through time define a sequence of stages of basin evolution. The depositional environments changed progressively from sheetflood dominant, via mobile ephemeral channels and floodplains to a more fixed channel–overbank system and eventually to a coastal plain. On the basis of the sedimentary record a progressive reduction in subsidence rate with time is deduced as the main control on the evolution of the basin fill. This deduction is consistent with predictions from previously applied extensional basin models, but is insufficiently refined at present to distinguish between the different models.

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Polar Lows over the Nordic Seas: Improved Representation in ERA-Interim Compared to ERA-40 and the Impact on Downscaled Simulations

Monthly Weather Review ◽

10.1175/mwr-d-13-00171.1 ◽

2014 ◽

Vol 142 (6) ◽

pp. 2271-2289 ◽

Cited By ~ 27

Author(s):

Thibaut Laffineur ◽

Chantal Claud ◽

Jean-Pierre Chaboureau ◽

Gunnar Noer

Keyword(s):

Barents Sea ◽

Mesoscale Model ◽

Cold Season ◽

Small Scale ◽

Polar Lows ◽

Wind Speeds ◽

Short Life Span ◽

Synoptic Conditions ◽

Polar Low ◽

The Impact

Abstract Polar lows are intense high-latitude mesocyclones that form during the cold season over open sea. Their relatively small-scale and short life span lead to a rather poor representation in model outputs and meteorological reanalyses. In this paper, the ability of the Interim European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-Interim) to represent polar lows over the Norwegian and Barents Sea is assessed, and a comparison with the 40-yr ECMWF Re-Analysis (ERA-40) is provided for three cold seasons (1999–2000 until 2001–02). A better representation in ERA-Interim is found, with 13 systems captured out of the 29 observed, against 6 in the case of ERA-40. Reasons for the lack of representation are identified. Unexpectedly, the representation of different polar low sizes does not appear to be linked to the resolution. Rather, it is the representation of synoptic conditions that appears to be essential. In a second part, a downscaling is conducted using the mesoscale model Méso-NH. For each observed polar low, a pair of simulations is performed: one initialized by ERA-Interim and the other one by ERA-40. An improvement is noted with 22 polar lows represented when ERA-Interim is used. Through a model-to-satellite approach, it is shown that even if polar lows are simulated, convective processes remain insufficiently represented. Wind speeds, which were underestimated in reanalyses, are nevertheless more realistic in the Méso-NH simulations. These results are supported by a spectral analysis of reanalyses and Méso-NH fields.

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Genetic differentiation between inshore and offshore populations of northern shrimp (Pandalus borealis)

ICES Journal of Marine Science ◽

10.1093/icesjms/fsab181 ◽

2021 ◽

Author(s):

Agneta Hansen ◽

Jon-Ivar Westgaard ◽

Guldborg Søvik ◽

Tanja Hanebrekke ◽

Einar Magnus Nilssen ◽

...

Keyword(s):

Genetic Structure ◽

Barents Sea ◽

General Trend ◽

The Arctic ◽

Small Scale ◽

Pandalus Borealis ◽

Mixed Heritage ◽

Northern Shrimp ◽

Significant Genetic Structure ◽

Genetic Clusters

Abstract Many marine organisms have a permanent presence both inshore and offshore and spawn in multiple areas, yet their status as separate populations or stocks remain unclear. This is the situation for the northern shrimp (Pandalus borealis) around the Arctic Ocean, which in northern Norway represents an important income for a small-scale coastal fishery and a large-vessel offshore fleet. In Norwegian waters, we uncovered two distinct genetic clusters, viz. a Norwegian coastal and a Barents Sea cluster. Shrimps with a mixed heritage from the Norwegian coastal and the Barents Sea clusters, and genetically different from both, inhabit the fjords at the northernmost coast (Finnmark). Genetic structure between fjords did not display any general trend, and only the Varangerfjord in eastern Finnmark displayed significant genetic structure within the fjord. Shrimps in the Finnmark fjords differed in some degree from shrimps both in the adjacent Barents Sea and along the rest of the coast and should probably be considered a separate management unit.

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