scholarly journals Amino acid composition and δ<sup>15</sup>N of suspended matter in the Arabian Sea

2013 ◽  
Vol 10 (8) ◽  
pp. 13317-13352
Author(s):  
B. Gaye ◽  
B. Nagel ◽  
K. Dähnke ◽  
T. Rixen ◽  
N. Lahajnar ◽  
...  
Keyword(s):  
Organic Matter ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Water Column ◽  
Acid Composition ◽  
Residence Time ◽  
Mixed Layer ◽  
Suspended Matter ◽  
Arabian Sea ◽  
Surface Mixed Layer

Abstract. Sedimentation in the ocean is fed by large aggregates produced in the surface mixed layer that sink rapidly through the water column. These particles sampled by sediment traps have often been proposed to interact by disaggregation and scavenging with a pool of fine suspended matter with very slow sinking velocities and thus a long residence time. We investigated the amino acid composition and stable nitrogen isotopic ratios of suspended matter sampled during the late SW monsoon season in the Arabian Sea and compared them to those of sinking particles to investigate organic matter degradation/modification during passage through the water column. We found that amino acid (AA) composition of mixed layer suspended matter corresponds more to fresh plankton and their aggregates, whereas AA composition of suspended matter in the sub-thermocline water column deviated progressively from mixed layer composition. We conclude that suspended matter in deep waters and in the mixed layers of oligotrophic stations is dominated by fine material that has a long residence time and organic matter that is resistant to degradation. Whereas SPM in areas of high primary productivity is essentially derived from fresh plankton and thus has a strong imprint of the subsurface nitrate source, SPM at oligotrophic stations and at subthermocline depths appears to exchange amino acids with the DOC pool influencing also the δ15N values.

scholarly journals Amino acid composition and <i>δ</i><sup>15</sup>N of suspended matter in the Arabian Sea: implications for organic matter sources and degradation

2013 ◽  
Vol 10 (11) ◽  
pp. 7689-7702 ◽  
Author(s):  
B. Gaye ◽  
B. Nagel ◽  
K. Dähnke ◽  
T. Rixen ◽  
N. Lahajnar ◽  
...  
Keyword(s):  
Organic Matter ◽  
Amino Acid ◽  
Water Column ◽  
Residence Time ◽  
Mixed Layer ◽  
Suspended Matter ◽  
Arabian Sea ◽  
Monsoon Season ◽  
Sediment Traps ◽  
Surface Mixed Layer

Abstract. Sedimentation in the ocean is fed by large aggregates produced in the surface mixed layer that sink rapidly through the water column. These particles sampled by sediment traps have often been proposed to interact by disaggregation and scavenging with a pool of fine suspended matter with very slow sinking velocities and thus a long residence time. We investigated the amino acid (AA) composition and stable nitrogen isotopic ratios of suspended matter (SPM) sampled during the late SW monsoon season in the Arabian Sea and compared them to those of sinking particles to understand organic matter degradation/modification during passage through the water column. We found that AA composition of mixed layer suspended matter corresponds more to fresh plankton and their aggregates, whereas AA composition of SPM in the sub-thermocline water column deviated progressively from mixed layer composition. We conclude that suspended matter in deep waters and in the mixed layers of oligotrophic stations is dominated by fine material that has a long residence time and organic matter that is resistant to degradation. SPM in areas of high primary productivity is essentially derived from fresh plankton and thus has a strong imprint of the subsurface nitrate source, whereas SPM at oligotrophic stations and at subthermocline depths appears to exchange amino acids and nitrogen isotopes with the dissolved organic carbon (DOC) pool influencing also the δ15N values.

Carbohydrate and amino acid composition of dissolved organic matter leached from soil

2007 ◽  
Vol 39 (11) ◽  
pp. 2926-2935 ◽  
Author(s):  
Holger Fischer ◽  
Axel Meyer ◽  
Klaus Fischer ◽  
Yakov Kuzyakov
Keyword(s):  
Organic Matter ◽  
Amino Acid ◽  
Dissolved Organic Matter ◽  
Amino Acid Composition ◽  
Acid Composition

Organic matter characteristics in a Mediterranean stream through amino acid composition: changes driven by intermittency

2011 ◽  
Vol 73 (4) ◽  
pp. 523-535 ◽  
Author(s):  
Irene Ylla ◽  
Isis Sanpera-Calbet ◽  
Isabel Muñoz ◽  
Anna M. Romaní ◽  
Sergi Sabater
Keyword(s):  
Organic Matter ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Mediterranean Stream ◽  
Composition Changes

Amino acid composition of soil organic matter

1998 ◽  
Vol 26 (3) ◽  
pp. 235-242 ◽  
Author(s):  
Z. N. Senwo ◽  
M. A. Tabatabai
Keyword(s):  
Organic Matter ◽  
Amino Acid ◽  
Soil Organic Matter ◽  
Amino Acid Composition ◽  
Acid Composition

scholarly journals Observed variability in the current field during summer monsoon experiments: Arabian Sea

MAUSAM ◽  
2021 ◽  
Vol 47 (4) ◽  
pp. 355-368
Author(s):  
R.R. RAO ◽  
K. V. SANIL KUMAR ◽  
BASIL MATHEW
Keyword(s):  
Time Series ◽  
Water Column ◽  
Summer Monsoon ◽  
Mixed Layer ◽  
Arabian Sea ◽  
Ocean Dynamics ◽  
Series Data ◽  
Surface Mixed Layer ◽  
Current Field ◽  
South Central

The observed short term variability in the current field of the upper layers at selected locations in the Arabian Sea is examined utilising the available short (1-2 weeks) time series of moored currentmeter records obtained from former USSR stationary ship polygons during MONSOON-77 and MONEX-79 field experiments. Supplementary time series data sets on surface wind, sub-surface temperature and salinity were also made use of to explain the observed structure and variability of current field, in the upper 2OOm water column. The thermal regime in the central Arabian Sea showed cooling and deepening of the surface mixed layer with the onset and progress of the summer monsoon during MONSOON- 77 while the corresponding variability was marginal in the western and south-central Arabian Sea during pre-onset regime of MONEX-79, The Ekman balance appeared to be limited to the mixed layer, only during pre-onset regime of MONSOON-77 and was absent during pre-onset and onset regimes of MONEX-79 suggesting the importance of internal ocean dynamics influencing the current field. Most of the current records showed rich structure with superposed oscillations extending over the entire 200m water column. During progress regime of MONSOON-77 and at the equatorial station during pre-onset regime of MONEX-79. dramatic reduction in the current strength is noticed from mixed layer to thermocline due to differences in the eddy viscosity. During MONEX-79, a strong subsurface core of southerly flow ( -100 cm/s) was noticed at the equator (49°E) even before the onset of monsoon. The vector time series of current-meter records subjected to rotary spectral analysis showed inertial oscillations in the flow regime more prominently during MONSOON-77 as compared to MONEX-79. R.R. RAO. K. V. SANIL [email protected] and BASIL [email protected]

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