scholarly journals Influence of Algal Production and Decomposition on the Carbon Isotope Signature of Labile Particulate Organic Matter on a Productive Continental Shelf Under the Stress of Coastal Hypoxia

2020 ◽  
Vol 7 ◽  
Author(s):  
Zixiang Yang ◽  
Han Zhang ◽  
Peihong Kang ◽  
Yangyang Zhao ◽  
Tiantian Tang
Keyword(s):  
Organic Matter ◽  
Continental Shelf ◽  
Carbon Isotope ◽  
Particulate Organic Matter ◽  
Algal Production ◽  
Isotope Signature

Carbon Isotope Ratios of Particulate Organic Matter in the Gulf of St. Lawrence

1979 ◽  
Vol 36 (6) ◽  
pp. 678-682 ◽  
Author(s):  
F. C. Tan ◽  
P. M. Strain
Keyword(s):  
Organic Matter ◽  
Surface Water ◽  
Organic Carbon ◽  
Carbon Isotope ◽  
Particulate Organic Matter ◽  
Surface Sediments ◽  
Isotope Ratios ◽  
Lawrence Estuary ◽  
Carbon Isotope Ratios ◽  
Surface Samples

Sixteen offshore surface samples within the Gulf of St. Lawrence show low δ13C values and are similar to eight offshore surface samples collected seaward of the Gulf of St. Lawrence. The δ13C surface values are consistent with δ13C values in plankton produced at the temperature found in the euphotic zone in the study area. Higher values are observed in four surface samples from the mouth of the St. Lawrence Estuary and probably result from high carbon demand during periods of high biological productivity. Lower values found in seven deep POC samples indicate changes in the nature of the POC caused by biological degradation of the organic matter. Significant differences (2–6‰) between the uniformly high δ13C values of the organic carbon in surface sediments and the low values of near-bottom water POC have been observed. The similarity between the δ13C values of surface water POC and the surface sediments suggest that surface water POC is an important source of organic carbon in surface sediments. Several observations of large vertical δ13C gradients in deep water POC suggest the presence of resuspended sediments 30–60 m above the sediment–water interface. Key words: particulate organic matter, carbon isotope ratios, isotope fractionation, sediment resuspension, sediment sources, Gulf of St. Lawrence

scholarly journals Characterization of particulate organic matter in the Lena River delta and adjacent nearshore zone, NE Siberia – Part I: Radiocarbon inventories

2015 ◽  
Vol 12 (12) ◽  
pp. 3769-3788 ◽  
Author(s):  
M. Winterfeld ◽  
T. Laepple ◽  
G. Mollenhauer
Keyword(s):  
Organic Matter ◽  
Carbon Isotope ◽  
Particulate Organic Matter ◽  
Coastal Erosion ◽  
Stable Carbon Isotope ◽  
Mixing Model ◽  
Transport Pathways ◽  
Particulate Nitrogen ◽  
Lena River ◽  
Lena Delta

Abstract. Particulate organic matter (POM) derived from permafrost soils and transported by the Lena River represents a quantitatively important terrestrial carbon pool exported to Laptev Sea sediments (next to POM derived from coastal erosion). Its fate in a future warming Arctic, i.e., its remobilization and remineralization after permafrost thawing as well as its transport pathways to and sequestration in marine sediments, is currently under debate. We present one of the first radiocarbon (14C) data sets for surface water POM within the Lena Delta sampled in the summers of 2009–2010 and spring 2011 (n = 30 samples). The bulk Δ14C values varied from −55 to −391 ‰ translating into 14C ages of 395 to 3920 years BP. We further estimated the fraction of soil-derived POM to our samples based on (1) particulate organic carbon to particulate nitrogen ratios (POC : PN) and (2) on the stable carbon isotope (δ13C) composition of our samples. Assuming that this phytoplankton POM has a modern 14C concentration, we inferred the 14C concentrations of the soil-derived POM fractions. The results ranged from −322 to −884 ‰ (i.e., 3060 to 17 250 14C years BP) for the POC : PN-based scenario and from −261 to −944 ‰ (i.e., 2370 to 23 100 14C years BP) for the δ13C-based scenario. Despite the limitations of our approach, the estimated Δ14C values of the soil-derived POM fractions seem to reflect the heterogeneous 14C concentrations of the Lena River catchment soils covering a range from Holocene to Pleistocene ages better than the bulk POM Δ14C values. We further used a dual-carbon-isotope three-end-member mixing model to distinguish between POM contributions from Holocene soils and Pleistocene Ice Complex (IC) deposits to our soil-derived POM fraction. IC contributions are comparatively low (mean of 0.14) compared to Holocene soils (mean of 0.32) and riverine phytoplankton (mean of 0.55), which could be explained with the restricted spatial distribution of IC deposits within the Lena catchment. Based on our newly calculated soil-derived POM Δ14C values, we propose an isotopic range for the riverine soil-derived POM end member with Δ14C of −495 ± 153 ‰ deduced from our δ13C-based binary mixing model and δ13C of −26.6 ± 1 ‰ deduced from our data of Lena Delta soils and literature values. These estimates can help to improve the dual-carbon-isotope simulations used to quantify contributions from riverine soil POM, Pleistocene IC POM from coastal erosion, and marine POM in Siberian shelf sediments.

scholarly journals Characterization of particulate organic matter in the Lena River Delta and adjacent nearshore zone, NE Siberia – Part 2: Radiocarbon inventories

2014 ◽  
Vol 11 (10) ◽  
pp. 14413-14451 ◽  
Author(s):  
M. Winterfeld ◽  
G. Mollenhauer
Keyword(s):  
Organic Matter ◽  
Carbon Isotope ◽  
Particulate Organic Matter ◽  
Coastal Erosion ◽  
Stable Carbon Isotope ◽  
Data Set ◽  
Transport Pathways ◽  
Particulate Nitrogen ◽  
Lena River ◽  
Lena Delta

Abstract. Particulate organic matter (POM) derived from permafrost soils and transported by the Lena River represents a quantitatively important terrestrial carbon pool exported to Laptev Sea sediments (next to POM derived from coastal erosion). Its fate in a future warming Arctic, i.e. its remobilization and remineralization after permafrost thawing as well as its transport pathways to and sequestration in marine sediments is currently under debate. We present the first radiocarbon (14C) data set of surface water POM within the Lena Delta sampled in summers 2009–2010 and spring 2011 (n = 30 samples). The bulk Δ14C concentrations varied from −55 to −391‰ translating into 14C ages of 395 to 3920 yr BP. We further estimated the fraction of phytoplankton-derived POM to our samples based on (1) particulate organic carbon to particulate nitrogen ratios (POC:PN) and (2) on the stable carbon isotope (Δ13C) composition of our samples. Assuming that this phytoplankton POM has a modern 14C signature we inferred the 14C concentrations of the soil-derived POM fractions. The results ranged from −258 to −768‰ (i.e. 2340 to 11 700 14C yr BP) for the POC:PN-based scenario and from −191 to −704‰ (i.e. 1640 to 9720 14C yrs BP). Despite the limitations of our approach, the estimated Δ14C concentrations of the soil-derived POM fractions seem to reflect the heterogeneous 14C signal of the Lena River catchment soils covering a range from Holocene to Pleistocene ages. We therefore propose a typical isotopic signature of riverine soil-derived POM with a Δ13C of −26.6 ± 1.1‰ deduced from our data of Lena Delta soils and published values, and a Δ14C concentration of −362 ± 123‰ deduced from our Δ13C-based estimates. These data can help to improve the dual-carbon-isotope simulations used to quantify contributions from riverine soil POM, Pleistocene ice complex POM from coastal erosion, and marine POM in Siberian shelf sediments.

Stable carbon isotope distribution of particulate organic matter in the ocean: a model study

2000 ◽  
Vol 72 (2-4) ◽  
pp. 131-150 ◽  
Author(s):  
Matthias Hofmann ◽  
Dieter A Wolf-Gladrow ◽  
Taro Takahashi ◽  
Steward C Sutherland ◽  
Katharina D Six ◽  
...  
Keyword(s):  
Organic Matter ◽  
Carbon Isotope ◽  
Particulate Organic Matter ◽  
Stable Carbon Isotope ◽  
Stable Carbon ◽  
Isotope Distribution ◽  
Model Study
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