Chemical composition of interstitial waters from sediments of brine-bearing deeps of the Red Sea

Data on concentrations of the major ions (Cl, SO4, Alk, Na, K, Ca, Mg, NH4) in interstitial waters from sediments of three brine-bearing deeps of the Red Sea rift zone are reported. Interstitial waters of the Atlantis-II Deep have the highest salinity (310.1 g/l), of the Discovery Deep - slightly lower (298.8 g/l), and of the Suakin Deep - the lowest (159.9 g/l). Interstitial waters of all three deeps are characterized by low, compared with sea water, absolute and relative concentrations of Mg and SO4 ions and have extremely low alkaline reserve (0.15-0.64 meq/l). Concentrations of K, Ca and especially Na and Cl ions, as compared with sea water, are highly increased. Interstitial waters from the deeps in study have high, compared with sea water, concentrations of NH4 (12-62 mg/l).

Composition of Fe-Mn nodules and crusts from the Cape Basin

Facies zonation of the Cape basin with respect to Fe-Mn nodules based on data from Cruise 43 of R/V Akademik Kurchatov and published data is presented. Three facies regions are distinguished: the southern end of the Walvis Ridge and seamounts, the continental slope of the Southwest Africa and the deep-water Cape Basin. Iron-manganese nodules in the first of these areas are predominantly sedimentary, those in the second area are diagenetic and those in the third are sedimentary-diagenetic. Chemical characteristics and type of metallogenic specialization for each of the regions are identified.

Chemical composition of zoobenthos and bottom sediments from the gas-hydrate seep area near the Paramushir Island, Kuril Island arc

Bioaccumulation of metals by zoobenthos was investigated during cruise 11A of R/V Akademik Mstislav Keldysh in the vicinity of a gas-hydrate seep off Paramushir Island in the Sea of Okhotsk. Atomic absorption studies of concentrations of Al, Fe, Mn, Ni, Cu and Zn in zoobenthos (polychaetes, bivalves, ophiurans and echinoderms) collected from depths of 700-800 m indicated that their concentrations in individuals near the seep were not significantly different from those in individuals from other communities. Obtained results indicate that sea urchins and holothurians (non-sorting bottom-feeders) can separate mineral fraction of ingested bottom material.