A novel proxy for terrestrial organic matter in sediments based on branched and isoprenoid tetraether lipids

Continental ice sheets are a key component of the Earth's climate system, but their internal dynamics need to be further studied. Since the last deglaciation, the northern Eurasian Fennoscandian Ice Sheet (FIS) has been connected to the Black Sea (BS) watershed, making this basin a suitable location to investigate former icesheet dynamics. Here, from a core retrieved in the BS, we combine the use of neodymium isotopes, high-resolution elemental analysis, and biomarkers to trace changes in sediment provenance and river runoff. We reveal cyclic releases of meltwater originating from Lake Disna, a proglacial lake linked to the FIS during Heinrich Stadial 1. Regional interactions within the climate-lake-FIS system, linked to changes in the availability of subglacial water, led to abrupt drainage cycles of the FIS into the BS watershed. This phenomenon raised the BS water level by ∼100 m until the sill of the Bosphorus Strait was reached, flooding the vast northwestern BS shelf and deeply affecting the hydrology and circulation of the BS and, probably, of the Marmara and Aegean Seas.ice dynamics | meltwater routing | European hydrographic network

show abstract

“…BIT-index values were calculated according to ref. 29. Mean analytical precision on the BIT-index values is 0.008.…”

Section: Methodsmentioning

confidence: 98%

“…Analytical conditions were similar to those described in ref. 29. BIT-index values were calculated according to ref.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Abrupt drainage cycles of the Fennoscandian Ice Sheet

Soulet

Ménot

Bayon

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…The R soil (Zhu et al, 2011;Dogrul Selver et al, 2012) and GDGT based BIT (Hopmans et al, 2004) indices have both been proposed as proxies for soil OC transport. Studies of surface sediments from river-estuary-shelf/ocean transects have identified a correlation between R soil and BIT indices (Zhu et al, 2011;Dogrul Selver et al, 2012, 2015.…”

Section: R Soil and R 0 Soilmentioning

confidence: 99%

Bacteriohopanepolyols in tropical soils and sediments from the Congo River catchment area

Spencer-Jones

Wagner

Dinga³

et al. 2015

Organic Geochemistry

Self Cite

View full text Add to dashboard Cite

a b s t r a c tThe Congo River basin drains the second largest area of tropical rainforest in the world, including a large proportion of pristine wetlands. We present the bacteriohopanepolyol (BHP) inventory of a suite of tropical soils and, from comparison with published data, propose some initial ideas on BHP distribution controls. Strong taxonomic controls on BHP production are evident in wetland sediments. Dominant within the suite were 35-aminobacteriohopane-31,32,33,34-tetrol (aminotetrol) and 35-aminobacterio hopane-30,31,32,33,34-pentol (aminopentol), indicating aerobic methanotrophy. A narrow range and low mean relative abundance of 30-(5 0 -adenosyl)hopane (adenosylhopane) and related compounds, collectively termed ''soil marker" BHPs, were observed in Congo soils (mean 17%, range 7.9-36% of total BHPs, n = 22) compared with literature data from temperate surface soils and Arctic surface soils (mean 36%, range 0-66% of total BHPs, n = 28) suggesting a greater rate of conversion of these BHP precursors to other structures.

show abstract

“…Additionally, we calculated the BIT index (Hopmans et al, 2004), which is the ratio between soil-derived branched GDGTs and aquatic crenarchaeol, and is a measure for the relative input of soil organic matter in marine sediments.…”

Section: Gdgt Analysismentioning

confidence: 99%