scholarly journals Stable Carbon Isotope Signature of Particulate Organic Matter in the Southwestern Sumatran Waters of the Eastern Indian Ocean

2019 ◽  
Vol 36 (2) ◽  
Author(s):  
A'an Johan Wahyudi ◽  
Afdal Afdal ◽  
Hanny Meirinawati
Keyword(s):  
Organic Matter ◽  
Stable Isotope ◽  
Indian Ocean ◽  
Carbon Isotope ◽  
Particulate Organic Matter ◽  
Stable Carbon Isotope ◽  
Eastern Indian Ocean ◽  
Twilight Zone ◽  
The South ◽  
Chl A

The Southwestern Sumatran Waters of the Eastern Indian Ocean are known to be affected by the South Java Current and the South Equatorial Counter Current. Many studies have been carried out in relation to upwelling and the Indonesian Through Flow. However, there has been no systematic study into the properties of the particulate organic matter in the Southwestern Sumatran Waters. Therefore, the organic matter in these waters in terms of its origin is unknown. As part of the Widya Nusantara Expedition 2015 research cruise, this study aimed to examine the stable isotope ?13C signature of particulate organic matter (POM), especially with regards to the origins of the organic matter. The stable isotope ?13C is complemented by other variables such as chlorophyll-a, particulate organic carbon (POC), and nutrients (phosphate, silicate, ammonium and nitrate). The POC tends to be depth-dependent. The values of ?13C are ?23.56, ?24.30 and ?24.06‰ for 5, 100 and 300 m depths, respectively. We found that POM tended to be isotopically lighter with increasing POC and chl-a, especially in the surface water, potentially due to the preferential lighter carbon isotope for metabolism by the primary producer. The origin of POM in the Southwestern Sumatran waters is marine end-member in the surface (up to 100 m depth) and mixed compositions at the surface of twilight zone (100–300 m depth). The next layer, i.e. twilight zone (more than 300 m depth), is terrigenous end-member. The surface POM of SSW, as shown in 5 m depth, is not freshly produced and tends to be either autochthonous or allochthonous.

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

scholarly journals Impact of the Strong Downwelling (Upwelling) on Small Pelagic Fish Production during the 2016 (2019) Negative (Positive) Indian Ocean Dipole Events in the Eastern Indian Ocean off Java

Climate ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 29
Author(s):  
Jonson Lumban-Gaol ◽  
Eko Siswanto ◽  
Kedarnath Mahapatra ◽  
Nyoman Metta Nyanakumara Natih ◽  
I Wayan Nurjaya ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Indian Ocean Dipole ◽  
Pelagic Fish ◽  
Eastern Indian Ocean ◽  
Fish Production ◽  
Small Pelagic Fish ◽  
Field Surveys ◽  
Chl A ◽  
Positive Indian Ocean Dipole ◽  
The Impact

Although researchers have investigated the impact of Indian Ocean Dipole (IOD) phases on human lives, only a few have examined such impacts on fisheries. In this study, we analyzed the influence of negative (positive) IOD phases on chlorophyll a (Chl-a) concentrations as an indicator of phytoplankton biomass and small pelagic fish production in the eastern Indian Ocean (EIO) off Java. We also conducted field surveys in the EIO off Palabuhanratu Bay at the peak (October) and the end (December) of the 2019 positive IOD phase. Our findings show that the Chl-a concentration had a strong and robust association with the 2016 (2019) negative (positive) IOD phases. The negative (positive) anomalous Chl-a concentration in the EIO off Java associated with the negative (positive) IOD phase induced strong downwelling (upwelling), leading to the preponderant decrease (increase) in small pelagic fish production in the EIO off Java.

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