Biogeochemistry and limnology in Antarctic subglacial weathering: molecular evidence of the linkage between subglacial silica input and primary producers in a perennially ice-covered lake

Abstract

We report a 6,000 years record of subglacial weathering and biogeochemical processes in two perennially ice-covered glacial lakes at Rundvågshetta, on the Soya Coast of Lützow-Holm Bay, East Antarctica. The two lakes, Lake Maruwan Oike and Lake Maruwan-minami, are located in a channel that drains subglacial water from the base of the East Antarctic ice sheet. Greenish-grayish organic-rich laminations in sediment cores from the lakes indicate continuous primary production affected by the inflow of subglacial meltwater containing relict carbon, nitrogen, sulfur, and other essential nutrients. Biogenic silica, amorphous hydrated silica, and DNA-based molecular signatures of sedimentary facies indicate that diatom assemblages are the dominant primary producers, supported by the input of inorganic silicon (Si) from the subglacial inflow. This study highlights the significance of subglacial water-rock interactions during physical and chemical weathering processes and the importance of such interactions for the supply of bioavailable nutrients.

Holocene paleolimnological changes in Rundvågshetta lakes of the Soya Coast region and their paleoenvironmental significance with glacio-isostatic uplift in East Antarctica

“…13 C, δ 15 N) δ 13 C and δ 15 S7 ). Their isotope ratios are consistent with the previously reported results regards to Lake Maruwan-oike pro les (Takano et al, 2015). On the other hand, vertical distribution of δ 13…”

“…3). Based on the previous report (Takano et al 2015), the principal component analysis (e.g., Jolliffe and Cadima, 2016) and the correlation matrix tables for major elements in two lake sediments at Rundvagshetta (e. The conventional and calibrated ages of TOC in the Maruwanminami-ike sediment core is shown in Table 1. Age-depth relationship showed that sedimentation rates were slightly increased with depth (Fig.…”

“…Lake sediment cores record global, regional and local signals, such as climatic change, changes in relative sea level (RSL), the advance and retreat of catchment glaciers, and paleoecology of biological production and biological species composition. Changes from marine to brackish and to freshwater environments are recorded in lake sediments in the Soya Coast region due to the retreat of glaciers and subsequent isostatic uplift during the middle and late Holocene (Seto et al 2002;Matsumoto et al 2010Matsumoto et al , 2014Takano et al 2012Takano et al , 2015Verleyen et al 2017). Based on the 10 Be/ 9 Be ratios obtained from the sediment of Lake Maruwan-oike, Sproson et al (2021) reported a substantial increase of sub-glacial meltwater ux (< 730%) between 4.1 and 3.6 ka BP at Rundvågshetta.…”

“…2 Methods/experimental 2.1 Study sites and samples Imura and co-workers reported an important archive that the compilation of fundamental data on lake locations, limnological properties, electric conductivity, and description of vegetation i.e., aquatic moss (Imura et al 2003). Rundvågshetta (69°54.5′ S, 39°02′E) is a rock headland at the southwest margin of the Rundvåg Glacier (Sawagaki and Hirakawa 1997;Miura et al 1998b;Takano et al 2015). Lake Maruwanminami-ike (69°54'37"S, 39°02'17"E) and Lake Maruwan-oike (69°54'26"S, 39°02'41"E) are located at Rundvågshetta in the Soya Coast of East Antarctica (Fig.…”

A diatom‐inferred record of lake variability during the last 900 years in Lützow–Holm Bay, East Antarctica

“…To assess whether the sediments were deposited in freshwater, we determined sediment nitrogen isotopic composition using an elemental analyser (Costech 4010 or Flash 2000) − isotope ratio mass spectrometer (ThermoFinnigan, Delta Plus or ThermoFinnigan Delta V Advantage) as described by Takano et al . (). Nitrogen isotopic compositions are expressed as per mil (‰) deviations as: δ 15 N = [( 15 N/ 14 N) sample /( 15 N/ 14 N) standard −1] × 1000 (‰ vs .…”