TY - JOUR A1 - Radosavljevic, Boris A1 - Lantuit, Hugues A1 - Knoblauch, Christian A1 - Couture, Nicole A1 - Herzschuh, Ulrike A1 - Fritz, Michael T1 - Arctic nearshore sediment dynamics - an example from Herschel Island - Qikiqtaruk, Canada JF - Journal of marine science and engineering N2 - Increasing arctic coastal erosion rates imply a greater release of sediments and organic matter into the coastal zone. With 213 sediment samples taken around Herschel Island-Qikiqtaruk, Canadian Beaufort Sea, we aimed to gain new insights on sediment dynamics and geochemical properties of a shallow arctic nearshore zone. Spatial characteristics of nearshore sediment texture (moderately to poorly sorted silt) are dictated by hydrodynamic processes, but ice-related processes also play a role. We determined organic matter (OM) distribution and inferred the origin and quality of organic carbon by C/N ratios and stable carbon isotopes delta C-13. The carbon content was higher offshore and in sheltered areas (mean: 1.0 wt.%., S.D.: 0.9) and the C/N ratios also showed a similar spatial pattern (mean: 11.1, S.D.: 3.1), while the delta C-13 (mean: -26.4 parts per thousand VPDB, S.D.: 0.4) distribution was more complex. We compared the geochemical parameters of our study with terrestrial and marine samples from other studies using a bootstrap approach. Sediments of the current study contained 6.5 times and 1.8 times less total organic carbon than undisturbed and disturbed terrestrial sediments, respectively. Therefore, degradation of OM and separation of carbon pools take place on land and continue in the nearshore zone, where OM is leached, mineralized, or transported beyond the study area. KW - permafrost KW - Arctic Ocean KW - stable carbon isotopes KW - nitrogen KW - sediment KW - chemistry KW - sediment dynamics KW - Beaufort Sea KW - grain size Y1 - 2022 U6 - https://doi.org/10.3390/jmse10111589 SN - 2077-1312 VL - 10 IS - 11 PB - MDPI CY - Basel ER - TY - JOUR A1 - Tanski, George A1 - Lantuit, Hugues A1 - Ruttor, Saskia A1 - Knoblauch, Christian A1 - Radosavljevic, Boris A1 - Strauß, Jens A1 - Wolter, Juliane A1 - Irrgang, Anna Maria A1 - Ramage, Justine Lucille A1 - Fritz, Michael T1 - Transformation of terrestrial organic matter along thermokarst-affected permafrost coasts in the Arctic JF - The science of the total environment : an international journal for scientific research into the environment and its relationship with man N2 - The changing climate in the Arctic has a profound impact on permafrost coasts, which are subject to intensified thermokarst formation and erosion. Consequently, terrestrial organic matter (OM) is mobilized and transported into the nearshore zone. Yet, little is known about the fate of mobilized OM before and after entering the ocean. In this study we investigated a retrogressive thaw slump (RTS) on Qikiqtaruk - Herschel Island (Yukon coast, Canada). The RTS was classified into an undisturbed, a disturbed (thermokarst-affected) and a nearshore zone and sampled systematically along transects. Samples were analyzed for total and dissolved organic carbon and nitrogen (TOC, DOC, TN, DN), stable carbon isotopes (delta C-13-TOC, delta C-13-DOC), and dissolved inorganic nitrogen (DIN), which were compared between the zones. C/N-ratios, delta C-13 signatures, and ammonium (NH4-N) concentrations were used as indicators for OM degradation along with biomarkers (n-alkanes, n-fatty adds, n-alcohols). Our results show that OM significantly decreases after disturbance with a TOC and DOC loss of 77 and 55% and a TN and DN loss of 53 and 48%, respectively. C/N-ratios decrease significantly, whereas NH4-N concentrations slightly increase in freshly thawed material. In the nearshore zone, OM contents are comparable to the disturbed zone. We suggest that the strong decrease in OM is caused by initial dilution with melted massive ice and immediate offshore transport via the thaw stream. In the mudpool and thaw stream, OM is subject to degradation, whereas in the slump floor the nitrogen decrease is caused by recolonizing vegetation. Within the nearshore zone of the ocean, heavier portions of OM are directly buried in marine sediments close to shore. We conclude that RTS have profound impacts on coastal environments in the Arctic. They mobilize nutrients from permafrost, substantially decrease OM contents and provide fresh water and nutrients at a point source. KW - Canadian Arctic KW - Coastal erosion KW - Retrogressive thaw slump KW - Biogeochemistry KW - Carbon degradation Y1 - 2017 U6 - https://doi.org/10.1016/j.scitotenv.2016.12.152 SN - 0048-9697 SN - 1879-1026 VL - 581 SP - 434 EP - 447 PB - Elsevier Science CY - Amsterdam ER - TY - GEN A1 - Radosavljevic, Boris A1 - Lantuit, Hugues A1 - Pollard, Wayne A1 - Overduin, Pier Paul A1 - Couture, Nicole A1 - Sachs, Torsten A1 - Helm, Veit A1 - Fritz, Michael T1 - Erosion and Flooding - Threats to Coastal Infrastructure in the Arctic: A Case Study from Herschel Island, Yukon Territory, Canada (vol 39, pg 900, 2016) T2 - Estuaries and coasts : journal of the Estuarine Research Federation Y1 - 2016 U6 - https://doi.org/10.1007/s12237-016-0115-z SN - 1559-2723 SN - 1559-2731 VL - 39 SP - 1294 EP - 1295 PB - Springer CY - New York ER - TY - JOUR A1 - Radosavljevic, Boris A1 - Lantuit, Hugues A1 - Pollard, Wayne A1 - Overduin, Pier Paul A1 - Couture, Nicole A1 - Sachs, Torsten A1 - Helm, Veit A1 - Fritz, Michael T1 - Erosion and Flooding-Threats to Coastal Infrastructure in the Arctic: A Case Study from Herschel Island, Yukon Territory, Canada JF - Estuaries and coasts : journal of the Estuarine Research Federation N2 - Arctic coastal infrastructure and cultural and archeological sites are increasingly vulnerable to erosion and flooding due to amplified warming of the Arctic, sea level rise, lengthening of open water periods, and a predicted increase in frequency of major storms. Mitigating these hazards necessitates decision-making tools at an appropriate scale. The objectives of this paper are to provide such a tool by assessing potential erosion and flood hazards at Herschel Island, a UNESCO World Heritage candidate site. This study focused on Simpson Point and the adjacent coastal sections because of their archeological, historical, and cultural significance. Shoreline movement was analyzed using the Digital Shoreline Analysis System (DSAS) after digitizing shorelines from 1952, 1970, 2000, and 2011. For purposes of this analysis, the coast was divided in seven coastal reaches (CRs) reflecting different morphologies and/or exposures. Using linear regression rates obtained from these data, projections of shoreline position were made for 20 and 50 years into the future. Flood hazard was assessed using a least cost path analysis based on a high-resolution light detection and ranging (LiDAR) dataset and current Intergovernmental Panel on Climate Change sea level estimates. Widespread erosion characterizes the study area. The rate of shoreline movement in different periods of the study ranges from -5.5 to 2.7 mI double dagger a(-1) (mean -0.6 mI double dagger a(-1)). Mean coastal retreat decreased from -0.6 mI double dagger a(-1) to -0.5 mI double dagger a(-1), for 1952-1970 and 1970-2000, respectively, and increased to -1.3 mI double dagger a(-1) in the period 2000-2011. Ice-rich coastal sections most exposed to wave attack exhibited the highest rates of coastal retreat. The geohazard map combines shoreline projections and flood hazard analyses to show that most of the spit area has extreme or very high flood hazard potential, and some buildings are vulnerable to coastal erosion. This study demonstrates that transgressive forcing may provide ample sediment for the expansion of depositional landforms, while growing more susceptible to overwash and flooding. KW - Arctic KW - Coastal erosion KW - UNESCO KW - Vulnerability mapping KW - Permafrost coasts Y1 - 2016 U6 - https://doi.org/10.1007/s12237-015-0046-0 SN - 1559-2723 SN - 1559-2731 VL - 39 SP - 900 EP - 915 PB - Springer CY - New York ER -