Fluvial suspended sediment yields over hours to millennia in the High Arctic at proglacial Lake Linnévatnet, Svalbard

Abstract

Sediment yield can be a sensitive indicator of catchment dynamics and environmental change. For a glacierized catchment in the High Arctic, we compiled and analyzed diverse sediment transfer data, spanning a wide range of temporal scales, to quantify catchment yields and explore landscape response to past and ongoing hydroclimatic variability. The dataset integrates rates of lake sedimentation from correlated varve records and repeated annual and seasonal sediment traps, augmented by multi‐year lake and fluvial monitoring. Consistent spatial patterns of deposition enabled reconstruction of catchment yields from varve‐ and trap‐based fluxes. We used hydroclimatic data and multivariate modeling to examine annual controls of sediment delivery over almost a century, and to examine shorter‐term controls of sediment transfer during peak glacier melt. Particle‐size analyses, especially for annual sediment traps, were used to further infer sediment transfer mechanisms and timing. Through the Medieval Warm Period and Little Ice Age, there were no apparent multi‐century trends in lake sedimentation rates, which were over three times greater than those during the mid‐Holocene when glaciers were diminished. Twentieth‐century sedimentation rates were greater than those of previous millennia, with a mid‐century step increase in mean yield from 240 to 425 Mg km−2 yr−1. Annual yields through the twentieth century showed significant positive relations with spring/summer temperature, rainfall, and peak discharge conditions. This finding is significant for the future of sediment transfer at Linnévatnet, and perhaps more broadly in the Arctic, where continued increases in temperature and rainfall are projected. For 2004–2010, annual yields ranged from 294 to 1330 Mg km−2 yr−1. Sediment trap volumes and particle‐size variations indicate that recent annual yields were largely dominated by spring to early summer transfer of relatively coarse‐grained sediment. Fluvial monitoring showed daily to hourly sediment transfer to be related to current and prior discharge, diurnal hysteresis, air temperature, and precipitation. Copyright © 2017 John Wiley & Sons, Ltd.

Modelling suspended sediment discharge in a glaciated Arctic catchment–Lake Peters, Northeast Brooks Range, Alaska

“…Further, inclusion of meteorological variables in sediment modeling can provide useful information for interpreting past climates from longer sedimentary records, and assessing sensitivity to climate change through hydroclimatic system forecasting (Forbes & Lamoureux, 2005;Gordeev, 2006;Lewis & Lamoureux, 2010;Syvitski, 2002). Despite potential advantages, multiple-regression models are uncommonly used for studying suspended sediment transfer in catchments above the Arctic Circle (Hodgkins, 1999;Hodson & Ferguson, 1999;Irvine-Fynn et al, 2005;Schiefer et al, 2017). In Arctic Alaska (defined hereafter as Alaskan land above the Arctic Circle-66.33°N), even simple sediment rating curves have rarely been constructed (Arnborg et al, 1967;Lamb & Toniolo, 2016;Rainwater & Guy, 1961;Trefry, Rember, & Trocine, 2004), thus there is limited knowledge of the magnitude of sediment loads and processes driving sediment transfer.…”

Sediment Trap Analysis in High-Arctic Lake Linnévatnet Indicates a Recent Shift in the Annual Hydrological Regime

“…The recent work of Nowak and Hodson (2013) and Schiefer et al, (2017) support the occurrence of a changing hydrological regime in high-Arctic proglacial lakes, reflected by a change in sedimentation as a result of anomalous meteorological conditions. Nowak and Hodson considered climate change's influence on the hydrology of high-Arctic catchments, and found changes most notable in the last 10 years, with warmer and wetter winters, effects most prominent in the fall shoulder season.…”

“…Annual sediment yields for 2004-2010 were variable from 294-1330 Mg km -2 yr -1 . Schiefer et al (2017) attributed increases in sedimentation occurring since the mid-21 st century to be positively related to temperate and precipitation, with high seasonal, daily and hour variability in 2010-2016. The 2016-2017 sediment yield data was not available for Schiefer et al (2017), however the additional data in Figure 4.3 firmly continues a trend of an increase in sediment yield over the past 7 years.…”

“…Schiefer et al (2017) attributed increases in sedimentation occurring since the mid-21 st century to be positively related to temperate and precipitation, with high seasonal, daily and hour variability in 2010-2016. The 2016-2017 sediment yield data was not available for Schiefer et al (2017), however the additional data in Figure 4.3 firmly continues a trend of an increase in sediment yield over the past 7 years. Continuing the study of sedimentation and catchment conditions in Linnédalen will allow for the identification of the annual dominant sedimentary process, highlighting changes in the high-arctic hydrological regime.…”

Which Drivers Control the Suspended Sediment Flux in a High Arctic Glacierized Basin (Werenskioldbreen, Spitsbergen)?

“…Climate-driven increases in the ablation rate, resulting from higher air temperatures, tend to strengthen the positive trend in suspended sediment yield from glacierized areas. The intense glacier erosion, observed through high suspended sediment loads, has been a dominant geomorphological process in the high latitudes for over the last 10,000 years, as marine and lacustrine sediments records show [2,3]. Recently, the suspended sediment yield and its dynamics appear to play an important role in the biological pump by delivering sediment-bound nutrients (Si, Fe, P, N) to glacier sourced estuaries and, potentially, to the open oceans [4][5][6][7][8].…”