Geochemistry of amino acids in interstitial water, Leg 116

Abstract

We report the results of dissolved free amino acid and hydrolyzable amino acid analysis from interstitial water samples collected from Ocean Drilling Project Leg 116. The total hydrolyzable amino acid (THAA) values range between 3.7 and 38.6 μM. They average 16.1 μM at Site 717; between 3.18 and 29.72 μM, averaging 13.66 μM at Site 718; and between 2.57 and 46.44 μM, averaging 14.60 μM at Site 719. The dissolved free amino acid (DFAA) values show between 2.24 and 37.7 μM, averaging 9.45 μM at Site 717; between 0.43 and 21.64 μM, averaging 10.1 μM at Site 718; and between 0.91 and 12.92 μM, averaging 6.6 μM. DFAA in the Bay of Bengal, at Sites 717, 718, and 719 constitute, in most cases, less than 50% of the THAA in the pore water at the sediment surface, and this ratio increases downsection. Concentrations approach 100% in the deepest interstitial water samples. Sulfate reduction and methane fermentation are the only bacterial processes acting in the deeper sediment samples. -from Authors