Concentration of dissolved amino acids from saline waters by ligand-exchange chromatography.

Amino acids dissolved in salt solutions may be concentrated and removed from the solution by ligand exchange on copper-Chelex 100 resin. Competing inorganic ligands do not interfere, and ion exchange with cations does not occur; thus loss of metal ion from this column is avoided. To test the potentiality of ligand exchange for chromatography, the type and nature of the dissolved amino compounds in sea water were investigated. The data revealed that the bulk of the dissolved amino compounds is present in a combined rather than a free state.

Black sea: recent sedimentary history.

Three distinct sedimentary units, which can be correlated throughout the basin, occur in cores collected from the Black Sea. Carbon-14 ages help to define the recent sedimentary history of the Black Sea.

Methane-derived marine carbonates of pleistocene age.

In some calcium carbonate-bearing sandstones from the edge of the continental shelf off the northeast United States, the deltaC(13) range is from -30 and -60 per mil for both aragonite and high-magnesium calcite. The deltaC(13) of co-existing shells of Modiolus sp. is normal (+ 1.7 to -2.7 per mil). The deltaO(18) values of around + 3.5 per mil in all samples suggest deposition at temperatures around 0 degrees C. Quaternary methane oxidized either chemically or microbiologically to carbon dioxide is the probable source of carbon in these carbonates.

Fossil membranes and cell wall fragments from a 7000-year-old Black Sea sediment.

Lamellar and tubular membranes and orgacnic fragments resemnbling bacterial cell walls were abundant in Black Sea sediments deposited between 3000 and 7000 years ago. This time period was marked by a gradual transition from a freshwater to a seawater environment. The resulting salinity gradient in the interstitial solutions probably promoted natural chromatography and dissolution, redeposition, and preservation of organic molecules. The preservation of organic structures may have resulted from the lack of dissolved oxygen, high concentrations of metal ions, and structural reorganization during compaction.

Red sea: detailed survey of hot-brine areas.

A bathymetric and geophysical survey of the Red Sea rift valley between 21 degrees 10' and 21 degrees 30'N has defined three separate pools of hot brines. The brines and their associated heavy metals are believed to be periodically discharged from the eastern side of the largest deep, Atlantis II. Cores taken from the flanks of the deeps show repetitive cycles of sedimentation of hydrous amorphous iron oxides which fill most of Atlantis II Deep.

Methane in lake kivu: new data bearing on its origin.

Lake Kivu, an African rift lake, contains about 50 cubic kilometers of methane (at standard temperature and pressure) in its deep water. Data resulting from two recent expeditions to the lake and a reevaluation of earlier data suggest that most of the methane was formed by bacteria from abiogenetic carbon dioxide and hydrogen, rather than being of volcanic origin or having formed from decomposing organic matter.