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Müller, Peter J (1975): Geochemical analysis of sediments and interstitial water in sediment cores from the North-West African continental margin and from the Central Pacific [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.548426, Supplement to: Müller, PJ (1975): Diagenese stickstoffhaltiger organischer Subtanzen in oxischen and anoxischen marinen Sedimenten. Meteor Forschungsergebnisse, Deutsche Forschungsgemeinschaft, Reihe C Geologie und Geophysik, Gebrüder Bornträger, Berlin, Stuttgart, C22, 1-60

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Abstract:
A. Continental slope sediments off Spanish-Sahara and Senegal contain up to 4% organic carbon and up to 0.4% total nitrogen. The highest concentrations were found in sediments from water depths between 1000 and 2000 m. The regional and vertical distribution of organic matter differs significantly. Off Spanish-Sahara the organic matter content of sediment deposited during glacial times (Wuerm, Late Riss) is high whereas sediments deposited during interglacial times (Recent, Eem) are low in organic matter. Opposite distribution was found in sediments off Senegal.
The sediments contain 30 to 130 ppm of fixed nitrogen. In most sediments this corresponds to 2-8 % of the total nitrogen. Only in sediments deposited during interglacial times off Spanish-Sahara up to 20 % of the total nitrogen is contained as inorganically bound nitrogen. Positive correlations of the fixed nitrogen concentrations to the amounts of clay, alumina, and potassium suggest that it is primarily fixed to illites.
The amino acid nitrogen and hexosamine nitrogen account for 17 to 26 % and 1.3 to 2.4 %, respectively of the total nitrogen content of the sediments. The concentrations vary between 200 and 850 ppm amino acid nitrogen and 20 to 70 ppm hexosamine nitrogen, both parallel the fluctiations of organic matter in the sediment.
Fulvic acids, humic acids, and the total organic matter of the sediments may be clearly differentiated from one another and their amino acid and hexosamine contents and their amino acid composition:
a) Fulvic acids contain only half as much amino acids as humic acids
b) The molar amino acid/hexosamine ratios of the fulvic acids are half those of the humic acids and the total organic matter of the sediment
c) The amino acid spectra of fulvic acids are characterized by an enrichment of aspartic acid, alanine, and methionine sulfoxide and a depletion of glycine, valine, isoleucine, leucine, tyrosine, phenylalanine, lysine, and arginine compared to the spectra of the humic acids and those of the total organic matter fraction of the sediment.
d) The amino acid spectra of the humic acids and those of the total organic matter fraction of the sediments are about the same with the exception that arginine is clearly enriched in the total organic matter.
In general, as indicated by the amino compounds humic acids resemble closer the total organic matter composition than the low molecular fulvic acids do. This supports the general idea that during the course of diagenesis in reducing sediments organic matter stabilizes from a fulvic-like structure to humic-like structure and finally to kerogen.
The decomposition rates of single aminio acids differ significantly from one another. Generally amino acids which are preferentially contained in humic acids and the total organic matter fraction show a smaller loss with time than those preferably well documented in case of the basic amino acids lysine and arginine which- although thermally unstable- are the most stable amino acids in the sediments. A favoured incorporation of these compounds into high molecular substances as well as into clay minerals may explain their relatively high “stability” in the sediment.
The nitrogen loss from the sediments due to the activity of sulphate-reducing bacteria amounts to 20-40 % of the total organic nitrogen now present. At least 40 % of the organic nitrogen which is liberated by sulphate-reducing bacteria can be explained ny decomposition of amino acids alone.
B. Deep-sea sediments from the Central Pacific
The deep-seas sediments contain 1 to 2 orders of magnitude less organic matter than the continental slope sediments off NW Africa, i.e. 0.04 to 0.3 % organic carbon.
The fixed nitrogen content of the deep-sea sediments ranges from 60 to 270 ppm or from 20 to 45 % of the total nitrogen content.
While ammonia is the prevailing inorganic nitrogen compound in anoxic pore waters, nitrate predominates in the oxic environment of the deep-sea sediments. Near the sediment/water interface interstital nitrate concentrations of around 30 µg-at. N/l were recorded. These generally increase with sediment depth by 10 to 15 µg-at. NO3- N/l. This suggests the presence of free oxygen and the activity of nitrifying bacteria in the interstitial waters.
The ammonia content of the interstitial water of the oxic deep-sea sediments ranges from 2 to 60 µg-at. N/l and thus is several orders of magnitude less than in anoxic sediments. In contrast to recorded nitrate gradients towards the sediments/water interface, there are no ammonia concentration gradients. However, ammonia concentrations appear to be characteristic for certain regional areas. It is suggested that this regional differentiation is caused by ion exchange reactions involving potassium and ammonium ions rather than by different decomposition rates of organic matter.
C. C/N ratios
All estimated C/N ratios of surface sediments vary between 3 and 9 in the deep-sea and the continental margin, respectively. Whereas the C/N ratios generally increase with depth in the sediment cores off NW Africa they decrease in the deep-sea cores. The lowest values of around 1.3 were found in the deeper sections of the deep-sea cores, the highest of around 10 in the sediments off NW Africa.
The wide range of the C/N ratios as well as their opposite behaviour with increasing sediment depth in both the deep-sea and continental margin sediment cores, can be attributed mainly to the combination of the following three factors:
1. Inorganic and organic substances bound within the latticed of clay minerals tend to decrease the C/N ratios.
2. Organic matter not protected by absorption on the clay minerals tends to increase C/N ratios
3. Diagenetic alteration of organic matter by micro-organisms tends to increase C/N ratios through preferential loss of nitrogen
The diagenetic changes of the microbially decomposable organic matter results in both oxic and anoxic environments in a preferential loss of nitrogen and hence in higher C/N ratios of the organic fraction. This holds true for most of the continental margin sediments off NW Africa which contain relatively high amounts of organic matter so that factors 2 and 3 predominate there.
The relative low C/N ratios of the sediments deposited during interglacial times off Spanish-Sahara, which are low in organic carbon, show the increasing influence of factor 1 – the nitrogen-rich organic substances bound to clay minerals.
In the deep-sea sediments from the Central Pacific this factor completely predominates so that the C/N rations of the sediments approach that of the substance absorbed to clay minerals with decreasing organic matter content. In the deeper core sections the unprotected organic matter has been completely destroyed so that the C/N ratios of the total sediments eventually fall into the same range as those of the pure clay mineral fraction.
Project(s):
Institute for Geosciences, Christian Albrechts University, Kiel (GIK/IfG)
Coverage:
Median Latitude: 14.544607 * Median Longitude: -76.400944 * South-bound Latitude: 3.766667 * West-bound Longitude: -151.666667 * North-bound Latitude: 23.498333 * East-bound Longitude: -17.306667
Date/Time Start: 1971-01-01T00:00:00 * Date/Time End: 1974-04-08T00:00:00
Event(s):
GIK10127-2 * Latitude: 13.695000 * Longitude: -151.655000 * Date/Time: 1973-07-06T00:00:00 * Elevation: -5686.0 m * Recovery: 0.45 m * Location: Pacific * Campaign: VA-05/4 * Basis: Valdivia (1961) * Method/Device: Box corer (Reineck) (BCR)
GIK10127-3 * Latitude: 13.708333 * Longitude: -151.666667 * Date/Time: 1973-07-06T00:00:00 * Elevation: -5718.0 m * Recovery: 5.11 m * Location: Pacific * Campaign: VA-05/4 * Basis: Valdivia (1961) * Method/Device: Kasten corer 15 cm (KAL15)
GIK10128-1 * Latitude: 10.486667 * Longitude: -151.366667 * Date/Time: 1973-07-06T00:00:00 * Elevation: -5068.0 m * Recovery: 0.45 m * Location: Pacific * Campaign: VA-05/4 * Basis: Valdivia (1961) * Method/Device: Box corer (Reineck) (BCR)
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
38 datasets

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Datasets listed in this publication series

  1. Müller, PJ (1975): Sediment and pore water geochemical analysis of sediment core GIK10127-2/3, Central Pacific (Table XIV). https://doi.org/10.1594/PANGAEA.526612
  2. Müller, PJ (1975): Pore water geochemical analysis of sediment core GIK10128-1, Central Pacific (Table XIV). https://doi.org/10.1594/PANGAEA.526590
  3. Müller, PJ (1975): Pore water geochemical analysis of sediment core GIK10129-1, Central Pacific (Table XIV). https://doi.org/10.1594/PANGAEA.526591
  4. Müller, PJ (1975): Pore water geochemical analysis of sediment core GIK10130-1, Central Pacific (Table XIV). https://doi.org/10.1594/PANGAEA.526592
  5. Müller, PJ (1975): Sediment and pore water geochemical analysis of sediment core GIK10132-1, Central Pacific (Table XIII). https://doi.org/10.1594/PANGAEA.526593
  6. Müller, PJ (1975): Pore water geochemical analysis of sediment core GIK10136-1, Central Pacific (Table XIV). https://doi.org/10.1594/PANGAEA.526594
  7. Müller, PJ (1975): Pore water geochemical analysis of sediment core GIK10140-1, Central Pacific (Table XV). https://doi.org/10.1594/PANGAEA.526595
  8. Müller, PJ (1975): Pore water geochemical analysis of sediment core GIK10141-1, Central Pacific (Table XV). https://doi.org/10.1594/PANGAEA.526596
  9. Müller, PJ (1975): Pore water geochemical analysis of sediment core GIK10142-1, Central Pacific (Table XV). https://doi.org/10.1594/PANGAEA.526597
  10. Müller, PJ (1975): Pore water geochemical analysis of sediment core GIK10144-1, Central Pacific (Table XV). https://doi.org/10.1594/PANGAEA.526598
  11. Müller, PJ (1975): Pore water geochemical analysis of sediment core GIK10145-1, Central Pacific (Table XV). https://doi.org/10.1594/PANGAEA.526599
  12. Müller, PJ (1975): Pore water geochemical analysis of sediment core GIK10147-1, Central Pacific (Table XV). https://doi.org/10.1594/PANGAEA.526600
  13. Müller, PJ (1975): Pore water geochemical analysis of sediment core GIK10148-1, Central Pacific (Table XV). https://doi.org/10.1594/PANGAEA.526601
  14. Müller, PJ (1975): Pore water geochemical analysis of sediment core GIK10149-1, Central Pacific (Table XV). https://doi.org/10.1594/PANGAEA.526602
  15. Müller, PJ (1975): Pore water geochemical analysis of sediment core GIK10175-1, Central Pacific (Table XV). https://doi.org/10.1594/PANGAEA.526603
  16. Müller, PJ (1975): Pore water geochemical analysis of sediment core GIK10176-1, Central Pacific (Table XV). https://doi.org/10.1594/PANGAEA.526604
  17. Müller, PJ (1975): Pore water geochemical analysis of sediment core GIK10178-1, Central Pacific (Table XV). https://doi.org/10.1594/PANGAEA.526605
  18. Müller, PJ (1975): Sediment and pore water geochemical analysis of sediment core GIK12310-4, NW African continental margin (Table II). https://doi.org/10.1594/PANGAEA.526614
  19. Müller, PJ (1975): Sediment and pore water geochemical analysis of sediment core GIK12327-4/5, NW African continental margin (Table VIIa, XII). https://doi.org/10.1594/PANGAEA.526615
  20. Müller, PJ (1975): Sediment and pore water geochemical analysis of sediment core GIK12328-4/5, NW African continental margin (Table V). https://doi.org/10.1594/PANGAEA.526616
  21. Müller, PJ (1975): Sediment and pore water geochemical analysis of sediment core GIK12329-4/5, NW African continental margin (Table IV, XII). https://doi.org/10.1594/PANGAEA.526617
  22. Müller, PJ (1975): Pore water geochemical analysis of sediment core GIK12331-1/2, NW African continental margin (Table XII). https://doi.org/10.1594/PANGAEA.526618
  23. Müller, PJ (1975): Sediment and pore water geochemical analysis of sediment core GIK12344-3/6, NW African continental margin (Table X). https://doi.org/10.1594/PANGAEA.526619
  24. Müller, PJ (1975): Amino acid analysis of the sedimentary organic matter in sediment core GIK12347-1/2, NW African continental margin (Table VIIIc). https://doi.org/10.1594/PANGAEA.526626
  25. Müller, PJ (1975): Amino acid analysis of fulvic acid in sediment core GIK12347-1/2, NW African continental margin (Table VIIId). https://doi.org/10.1594/PANGAEA.526632
  26. Müller, PJ (1975): Relative abundance of amino acids of fulvic acid in sediment core GIK12347-1/2, NW African continental margin (Table VIIIe). https://doi.org/10.1594/PANGAEA.526639
  27. Müller, PJ (1975): Amino acid analysis of humic acid in sediment core GIK12347-1/2, NW African continental margin (Table VIIId). https://doi.org/10.1594/PANGAEA.526634
  28. Müller, PJ (1975): Relative abundance of amino acids of humic acid in sediment core GIK12347-1/2, NW African continental margin (Table VIIIe). https://doi.org/10.1594/PANGAEA.526637
  29. Müller, PJ (1975): Amino acid analysis of the sediment in sediment core GIK12347-1/2, NW African continental margin (Table VIIIb). https://doi.org/10.1594/PANGAEA.526630
  30. Müller, PJ (1975): Relative abundance of amino acids in the sediment of sediment core GIK12347-1/2, NW African continental margin (Table VIIIe). https://doi.org/10.1594/PANGAEA.526635
  31. Müller, PJ (1975): Sediment and pore water geochemical analysis of sediment core GIK12347-1/2, NW African continental margin (Table VIIIa). https://doi.org/10.1594/PANGAEA.526620
  32. Müller, PJ (1975): Amino acid analysis of the sedimentary organic matter in sediment core GIK12379-1, NW African continental margin (Table VIIc). https://doi.org/10.1594/PANGAEA.526622
  33. Müller, PJ (1975): Amino acid analysis of fulvic acid in sediment core GIK12379-1, NW African continental margin (Table VIId). https://doi.org/10.1594/PANGAEA.526631
  34. Müller, PJ (1975): Relative abundance of amino acids of fulvic acid in sediment core GIK12379-1, NW African continental margin (Table VIIe). https://doi.org/10.1594/PANGAEA.526640
  35. Müller, PJ (1975): Amino acid analysis of humic acid in sediment core GIK12379-1, NW African continental margin (Table VIId). https://doi.org/10.1594/PANGAEA.526633
  36. Müller, PJ (1975): Relative abundance of amino acids of humic acid in sediment core GIK12379-1, NW African continental margin (Table VIIe). https://doi.org/10.1594/PANGAEA.526638
  37. Müller, PJ (1975): Amino acid analysis of the sediment in sediment core GIK12379-1, NW African continental margin (Table VIIb). https://doi.org/10.1594/PANGAEA.526628
  38. Müller, PJ (1975): Relative abundance of amino acids in the sediment of sediment core GIK12379-1, NW African continental margin (Table VIIe). https://doi.org/10.1594/PANGAEA.526636