No abstract

Fjords on the West Antarctic Peninsula (WAP) serve as sediment traps, preserving histories of glacial sediment supply. Regional warming trends are expected to change sediment supplies, altering water quality, depositional history, and ecosystem drivers. Our ability to assess magnitudes of these changes is limited by sparse data on modern sediment accumulation. Twelve new cores and four existing cores from Andvord Bay were used to characterize variability in sediment accumulation rates. These range from 1.5 to 7.9 mm/year (0.12 to 0.56 g·cm−2·year−1). Spatial differences and a weak down‐fjord gradient in rates suggest diverse sediment sources, including from outside the fjord. This data set provides a comprehensive assessment of sedimentation during the past century, indicating little change in rates due to recent WAP warming, and sets a benchmark for assessing climate‐related changes in sediment delivery and ecosystem drivers (e.g., burial disturbance) in the fjord over coming decades.

No abstract

In areas unaffected by the high flux of organic matter and rapid/thick flood deposition, or in between flood events, the conditions for methanogenesis and gas accumulation have not been met. In these areas, the physical and biological reworking of the surficial sediment may effectively oxidize and mineralize organic matter and limit bacterial methanogenesis in the subsurface. We propose that in the Rhône prodelta flood deposits deliver significant amounts of terrigenous 1 organic matter that can be rapidly buried, effectively removing this organic matter from aerobic oxidation and biological uptake, and leading to the potential for methanogenesis with burial.

No abstract