Amino Acids In Interstitial Waters Research Articles

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

Biogenic calcareous and siliceous sediments were drilled at ODP Sites 689 and 690 on the Maud Rise, Antarctic Ocean. We analyzed dissolved combined amino acids (DCAA) and dissolved free amino acids (DFAA) in interstitial waters in order to characterize the amino acids in dissolved organic matter. The DFAA was predominant over the DCAA in interstitial waters at Sites 689 and 690, which contradicted the previous results from interstitial water and seawater studies. The DCAA in the interstitial waters probably originated from calcareous biogenic debris with less amounts of siliceous debris. Although glutamic acid constituted 41% of the total concentration of DCAA, it accounted for only 1% of the total concentration of DFAA due to the adsorption and/or reaction with biogenic carbonate. Ornithine, a nonprotein amino acid, is a decomposed product of arginine and made up 17 mol% of the total DFAA and. The total hydrolyzable amino acids (=DCAA + DFAA) accounted for 5 to 28% of the dissolved organic carbon (DOC) concentration, which implied that high molecular weight organic matter was a major contributor for the DOM (dissolved organic matter) in interstitial waters. Fairly positive correlation between the dissolved manganese and the total DCAA values suggested that the redox condition plays a significant role in controlling the total DCAA content. A small decrease in the sulfate concentration in the interstitial waters from both sites suggested fairly low microbial activity by sulfate-reducing bacteria.

Amino acids in interstitial waters of marine sediments: a comparison of results from varied sedimentary environments

High concentrations of dissolved free amino acids, ranging from 2 to 95 μM, have been measured in interstitial waters of marine sediments from Buzzards Bay (Massachusetts), the northwestern Atlantic, and the Peru upwelling region. Amino acid concentrations were highest in the interstitial water at or near the sediment-water interface, and decreased with depth in the sediment. The amino acid composition varied systematically with depth in the sediment and with depositional environment. Glutamic and β-aminoglutaric acids were important constituents of most samples, especially those from anoxic sediments.

Dissolved Free Amino Acids in Interstitial Waters of Georgia Salt Marsh Soils

The patterns of concentration of dissolved free amino acids (DFAA) are different and more variable in pore water of soils from a Georgia salt marsh than in most surface waters. Elevated concentrations of DFAA (up to 8850 nmoles liter−1) and high relative levels of alanine and glutamic acid suggest that bacteria may produce these amino acids. In addition to the common protein amino acids, an unidentified compound was present and was the dominant free amino acid in some sections. This compound appeared to be specific to pore waters as it was not observed in surface waters or in hydrolysates of sediments, bacteria or plants from the marsk.

Amino acids in interstitial waters of marine sediments

DISEQUILIBRIA within the mixture of organic matter, mineral particles and seawater in near-surface sediments result in extensive reaction, often biologically mediated. Variations in interstitial water composition are very sensitive indicators of the chemical and biological reactions in this zone of transition and the interaction between the water column and the permanent deposit1,2. Although most studies have been confined to inorganic ions, the few measurements of pore water DOC in marine sediments3–6 show large gradients in dissolved organic matter concentration within sediments and across the sediment–water interface. We describe here our study of dissolved amino acids in interstitial waters, which were used to trace some of the biogeochemical processes affecting organic matter in marine sediments. We have analysed the dissolved free amino acids in 15 interstitial water samples from four cores obtained in Buzzards Bay, Massachusetts; the Gulf of Maine; and the North-west Atlantic continental rise. These pore waters have very high amino acid concentrations, of the order of 1 mg l−1. In addition, the distribution of individual amino acids differs substantially from that reported for seawater7,8, particularly in the large relative abundance of glutamic acid and β-aminoglutaric acid. β-aminoglutaric acid (HOOCCH2CH(NH2)CH2COOH) is an isomer of glutamic acid which, to our knowledge, has not been previously reported in the marine environment.