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The hydrogen isotope ratio (δ2H) of lipid biomarkers from phytoplankton and terrestrial plants were measured in surface sediments from Chinese marginal seas (CMS), in order to evaluate processes affecting their spatial distribution, and by extension, the controls on organic carbon cycling in these dynamic marginal seas. The dinoflagellate sterol dinosterol and the microalgal sterol brassicasterol had low δ2H values (<−300%) near the mouth of the Yangtze River. Near the mouth of the Yellow River, dinosterol again had low δ2H values but brassicasterol had intermediate (−292 to −281%) δ2H values. This discrepancy in the δ2H values of two phytoplankton sterols may be explained by the timing of dinoflagellate production relative to that of brassicasterol producers (e.g., diatoms). The δ2H values of C16:0 fatty acid, synthesized by all organisms, had intermediate δ2H values (−199 to −178%) near the Yangtze River and lowest δ2H C16:0 values (−216 to −206%) occurred near the old Yellow River delta. The lowest δ2H C28:0 values (<−184%) occurred adjacent to rivers, suggesting that leaf‐wax lipids produced on the loess plateau, which are enriched in 2H, may contribute less to the nearshore environment than the offshore regions. Higher δ2H C28:0 values offshore may be explained by a larger contribution of leaf wax fatty acids from aerosols relative to river‐borne suspended particles. Lipid biomarker δ2H fingerprinting thus provides a new tool for deciphering the controls on organic carbon cycling and accumulation in the dynamic CMS. Plain Language Summary: Most carbon burial in the ocean occurs in continental shelf sediments even though they comprise a small fraction of the ocean area. Almost 10 percent of this nearshore carbon burial occurs in the Chinese marginal seas where the Yellow River and Yangtze Rivers discharge their massive sediment loads. This study applies a new tool, hydrogen isotope ratios in lipid biomarkers, to unravel the inner workings of the carbon cycle in the coastal seas of China. By focusing on the hydrogen bonded to carbon it is possible to determine things like where on land organic carbon was produced, where in the ocean marine organic carbon was produced, and the environmental conditions under which that organic material was synthesized. It was found that the dinoflagellate sterol dinosterol and the microalgal sterol brassicasterol had low δ2H values near the mouth of the Yangtze River where freshwater runoff with low δ2H values. The δ2H values of the C28:0 leaf‐wax fatty acid from terrestrial plants were higher than for the C16:0, owing to the isotopic enrichment of leaf water during evapotranspiration. The highest δ2H values for C28:0 occurred offshore, suggesting that leaf wax lipids produced on the loess plateau contribute substantially to the offshore region. Key Points: δ2H values of sedimentary sterols and fatty acids informs processes influencing OC cycling in Chinese Marginal SeasLowest δ2H values of phytoplankton sterols occur near Yangtze River deltaδ2H values of C28:0 and C16:0 fatty acids have different spatial patterns [ABSTRACT FROM AUTHOR]

Abstract: Species composition and vertical distribution of planktonic organisms in Lakes Lalolalo, Lanutavake, and Lano on the Pacific island of Uvea were investigated in relation to physicochemical water column profiles [...]

We present the first detailed record of Holocene climate variation from Icelandic eolian soil deposits. Seven cold and windy episodes occurred in Iceland during the past 10 k.y., including the well-documented Little Ice Age (0.6-0.1 ka) and the 8.2 ka event. These windy events are associated with enhanced drift-ice discharge into the North Atlantic, and several are associated with evidence for cold and windy climate in central Greenland and diminution of deep-water formation in the North Atlantic. Although the Arctic Oscillation-North Atlantic Oscillation (AO-NAO) has been invoked to explain other climate teleconnections in the North Atlantic, our paleorecord of windiness in Iceland is not consistent with a persistent negative phase of the AO-NAO. Keywords: Holocene, Iceland, wind transport, grain-size analysis, loess, paleoclimate.

Author(s): Julian P. Sachs (corresponding author) [1]; Robert F. Anderson [2] Massive iceberg discharges from the Northern Hemisphere ice sheets, 'Heinrich events', coincided with the coldest periods of the last [...]