Amino Acids in the Interstitial Waters from ODP Site 695 in the Weddell Sea|Antarctic Ocean

Abstract

Site 695 lies on the southeast margin of the South Orkney microcontinent on the northern margin of the Weddell Sea, at 62°23.48'S, 43°27.10'W in 1305 m water depth. The inorganic properties of interstitial waters at this site, including sulfate reduction, biogenic methane production, and high concentrations of ammonia and phosphate, imply high microbial activity. However, no clear relationship between amino acid composition and concentration and the type of microbial activity (e.g., sulfate reduction or methane production) can be identified.The THAA (total hydrolyzable amino acids) values range between 2.45 and 17.31 jumol/L, averaging 7.14 ^mol/L. The mean concentrations and relative abundance values of acidic, basic, neutral, aromatic, and sulfur-containing amino acids are 1.34 (18%), 1.09 (15%), 3.93 (54%), 0.50 (8%), and 0.02 (0%) /xmol/L, respectively. Glycine is the most abundant amino acid residue, with serine, glutamic acid, and ornithine next. The DFAA (dissolved free amino acids) values range from 0.10 to 12.73 junol/L, averaging 4.07 /rniol/L. The acidic, basic, neutral, aromatic, and sulfurcontaining amino acids are on average 0.21, 0.79, 2.56, 0.41, and 0.01 /xmol/L, respectively. The relative abundances of acidic, basic, neutral, and aromatic amino acids average 4%, 18%, 58%, and 15%, respectively.Predominance of DFAA over DCAA (dissolved combined amino acids) in interstitial waters of Lithologic Units I and II is contrary to the predominance of DCAA over DFAA in other interstitial waters and seawater.The comparison of amino acid compositions between DCAA and siliceous plankton suggests that the DCAA in interstitial waters originally comes from amino acids derived from siliceous plankton. However, other sources which are much enriched in glutamic acid contribute to the DCAA composition.

Amino Acids in Interstitial Waters from Sites 790 and 791 in the Izu-Bonin Island Arc

“…Thus, the dissolved combined amino acids (DCAA) in interstitial waters as well as the DFAA seem to be sensitive and important indicators of early diagenesis. However, little work on this subject, particularly on DCAA in interstitial waters, has been done (Ishizuka et al, 1988;Kawahata and Ishizuka, 1989;Kawahata et al, 1990;Ishizuka et al, 1990). Therefore, this paper presents the results of the DFAA, DCAA, and total hydrolyzable amino acids (THAA) in interstitial waters collected Taylor, B., Fujioka, K., et al, 1992.…”

Amino acids in interstitial waters from ODP Sites 689 and 690 on the Maud Rise, Antarctic Ocean.

“…Thus, DCAA and DFAA in interstitial waters seem to be sensitive and important indicators of early diagenesis. So far, little work on this subject, particularly on DCAA in interstitial waters, has been carried out in deep sedimentary holes (e.g., Ishizuka et al, 1988;Kawahata and Ishizuka, 1989, 1993Kawahata et al, 1990). This paper presents the results of the DCAA and DFAA in interstitial waters collected at Sites 689 and 690 during Ocean Drilling Program (ODP) Leg 113, and discusses the characteristics of DCAA and DFAA and the relationship between the DCAA, DFAA and dissolved organic carbon (DOC) in interstitial waters.…”