High-concentration sediment plumes, Horseshoe Island, western Antarctic Peninsula

2021 ◽  
pp. 1-4
Author(s):  
CRISTIAN RODRIGO ◽  
ANDRÉS VARAS-GÓMEZ ◽  
ADRIÁN BUSTAMANTE-MAINO ◽  
EMILIO MENA-HODGES
Keyword(s):  
Antarctic Peninsula ◽  
Short Note ◽  
Sediment Concentration ◽  
Change Scenario ◽  
High Concentration ◽  
Tidewater Glaciers ◽  
Marguerite Bay ◽  
Southern Side ◽  
Reported Data ◽  
The Antarctic

The variability in sediment concentration and spatial distribution of meltwater discharges from tidewater glaciers can be used to elucidate climatic evolution and glacier behaviour due to the association between sediment yield and glacier retreat (e.g. Domack & McClennen 1996). In an accelerated deglaciation environment, higher sediment concentrations in the water column can change the glacimarine costal dynamics and affect productivity and sea floor ecosystems (e.g. Marín et al. 2013). In the Antarctic Peninsula Region, meltwater or turbid plumes were previously believed to be rare or without an important role in the sedimentary glacimarine environment (e.g. Griffith & Anderson 1989), but recent studies have shown that this is a common phenomenon in subpolar and transition polar climates (Yoo et al. 2015, Rodrigo et al. 2016). In the current climate change scenario, accelerated glacier retreats and mass losses can produce an increasing input of glacial meltwater into the fjord regions, a situation that is not yet well evaluated in the Antarctic Peninsula. In this short note, after in situ observation of an unusual waterfall from the southern side of the main western tidewater glacier (Shoesmith Glacier) of Horseshoe Island (Lystad Bay), Marguerite Bay (Fig. 1), we report high turbidity values associated with plumes from the glacier, whose values were higher than reported data from subpolar/transition polar Antarctic climates.

scholarly journals Discharge of debris from ice at the margin of the Greenland ice sheet

2002 ◽  
Vol 48 (161) ◽  
pp. 192-198 ◽  
Author(s):  
Peter G. Knight ◽  
Richard I. Waller ◽  
Carrie J. Patterson ◽  
Alison P. Jones ◽  
Zoe P. Robinson
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
High Rate ◽  
Outlet Glacier ◽  
Tidewater Glaciers ◽  
Sediment Production ◽  
Basal Ice ◽  
Order Of Magnitude ◽  
Sediment Transfer ◽  
A Minor

AbstractSediment production at a terrestrial section of the ice-sheet margin in West Greenland is dominated by debris released through the basal ice layer. The debris flux through the basal ice at the margin is estimated to be 12–45 m3 m−1 a−1. This is three orders of magnitude higher than that previously reported for East Antarctica, an order of magnitude higher than sites reported from in Norway, Iceland and Switzerland, but an order of magnitude lower than values previously reported from tidewater glaciers in Alaska and other high-rate environments such as surging glaciers. At our site, only negligible amounts of debris are released through englacial, supraglacial or subglacial sediment transfer. Glaciofluvial sediment production is highly localized, and long sections of the ice-sheet margin receive no sediment from glaciofluvial sources. These findings differ from those of studies at more temperate glacial settings where glaciofluvial routes are dominant and basal ice contributes only a minor percentage of the debris released at the margin. These data on debris flux through the terrestrial margin of an outlet glacier contribute to our limited knowledge of debris production from the Greenland ice sheet.

A new Antarctic foraminiferal species for detecting climate change in sub-Recent glacier-proximal sediments

2009 ◽  
Vol 21 (5) ◽  
pp. 439-448 ◽  
Author(s):  
Wojciech Majewski ◽  
Andrzej Tatur
Keyword(s):  
Climate Change ◽  
Climate Warming ◽  
The Arctic ◽  
South Shetland Islands ◽  
King George Island ◽  
Tidewater Glaciers ◽  
Admiralty Bay ◽  
Shetland Islands ◽  
Foraminiferal Species ◽  
Water Depths

AbstractCribroelphidium webbi sp. nov. is the only adequately described sub-Recent elphidiid foraminifer from Antarctica. In Admiralty Bay (King George Island, South Shetland Islands), it is found at several locations within inner fiord setting at water depths between 33 and 165 m, but most commonly shallower than 100 m. In outer basins this foraminifer is absent. In the cores analysed, C. webbi sp. nov. is present in well-constrained sub-Recent horizons that are clearly related to climate warming and deglaciation. These horizons represent a diachronous facies marker rather than a single stratigraphic layer. Cribroelphidium webbi sp. nov. shows clear association with retreating tidewater glaciers, therefore it is an important sensitive glacier-proximal indicator. It appears that it shares similar ecologic affinities with Cribroelphidium excavatum clavatum, which is widely distributed throughout the Arctic.

scholarly journals A mass-flux perspective of the tidewater glacier cycle

2016 ◽  
Vol 62 (231) ◽  
pp. 82-93 ◽  
Author(s):  
JASON M. AMUNDSON
Keyword(s):  
Deep Water ◽  
Mass Flux ◽  
Large Scale ◽  
Stable Configuration ◽  
Simple Explanation ◽  
Surface Mass ◽  
Tidewater Glaciers ◽  
Tidewater Glacier ◽  
Variable Sensitivity ◽  
Negative Feedbacks

AbstractI explore the tidewater glacier cycle with a 1-D, depth- and width-integrated flow model that includes a mass-flux calving parameterization. The parameterization is developed from mass continuity arguments and relates the calving rate to the terminus velocity and the terminus balance velocity. The model demonstrates variable sensitivity to climate. From an advanced, stable configuration, a small warming of the climate triggers a rapid retreat that causes large-scale drawdown and is enhanced by positive glacier-dynamic feedbacks. Eventually, the terminus retreats out of deep water and the terminus velocity decreases, resulting in reduced drawdown and the potential for restabilization. Terminus readvance can be initiated by cooling the climate. Terminus advance into deep water is difficult to sustain, however, due to negative feedbacks between glacier dynamics and surface mass balance. Despite uncertainty in the precise form of the parameterization, the model provides a simple explanation of the tidewater glacier cycle and can be used to evaluate the response of tidewater glaciers to climate variability. It also highlights the importance of improving parameterizations of calving rates and of incorporating sediment dynamics into tidewater glacier models.

Geometric Constraints on Glacial Fjord-Shelf Exchange

2021 ◽  
Author(s):  
Ken X. Zhao ◽  
Andrew L. Stewart ◽  
James C. McWilliams
Keyword(s):  
Continental Shelf ◽  
Water Mass ◽  
Geometric Constraints ◽  
Overturning Circulation ◽  
Tidewater Glaciers ◽  
First Order ◽  
West Antarctic ◽  
Vorticity Budget ◽  
Sill Height ◽  
Water Mass Transformation

AbstractThe oceanic connections between tidewater glaciers and continental shelf waters are modulated and controlled by geometrically complex fjords. These fjords exhibit both overturning circulations and horizontal recirculations, driven by a combination of water mass transformation at the head of the fjord, variability on the continental shelf, and atmospheric forcing. However, it remains unclear which geometric and forcing parameters are the most important in exerting control on the overturning and horizontal recirculation. To address this, idealized numerical simulations are conducted using an isopycnal model of a fjord connected to a continental shelf, which is representative of regions in Greenland and the West Antarctic Peninsula. A range of sensitivity experiments demonstrate that sill height, wind direction/strength, subglacial discharge strength, and depth of offshore warm water are of first-order importance to the overturning circulation, while fjord width is also of leading importance to the horizontal recirculation. Dynamical predictions are developed and tested for the overturning circulation of the entire shelf-to-glacierface domain, subdivided into three regions: the continental shelf extending from the open ocean to the fjord mouth, the sill-overflow at the fjord mouth, and the plume-driven water mass transformation at the fjord head. A vorticity budget is also developed to predict the strength of the horizontal recirculation, which provides a scaling in terms of the overturning and bottom friction. Based on these theories, we may predict glacial melt rates that take into account overturning and recirculation, which may be used to refine estimates of ocean-driven melting of the Greenland and Antarctic ice sheets.

scholarly journals Dynamics of Three-Dimensional Turbulent Wall Plumes and Implications for Estimates of Submarine Glacier Melting

2018 ◽  
Vol 48 (9) ◽  
pp. 1941-1950 ◽  
Author(s):  
Ekaterina Ezhova ◽  
Claudia Cenedese ◽  
Luca Brandt
Keyword(s):  
Three Dimensional ◽  
Characteristic Parameters ◽  
Buoyant Plumes ◽  
Tidewater Glaciers ◽  
Glacier Melting ◽  
Order Of Magnitude ◽  
Layer Flow ◽  
Using Data ◽  
Turbulent Wall ◽  
Wall Plume

AbstractSubglacial discharges have been observed to generate buoyant plumes along the ice face of Greenland tidewater glaciers. These plumes have been traditionally modeled using classical plume theory, and their characteristic parameters (e.g., velocity) are employed in the widely used three-equation melt parameterization. However, the applicability of plume theory for three-dimensional turbulent wall plumes is questionable because of the complex near-wall plume dynamics. In this study, corrections to the classical plume theory are introduced to account for the presence of a wall. In particular, the drag and entrainment coefficients are quantified for a three-dimensional turbulent wall plume using data from direct numerical simulations. The drag coefficient is found to be an order of magnitude larger than that for a boundary layer flow over a flat plate at a similar Reynolds number. This result suggests a significant increase in the melting estimates by the current parameterization. However, the volume flux in a wall plume is found to be one-half that of a conical plume that has 2 times the buoyancy flux. This finding suggests that the total entrainment (per unit area) of ambient water is the same and that the plume scalar characteristics (i.e., temperature and salinity) can be predicted reasonably well using classical plume theory.

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