(Table 2) Characteristics of influence of cyclonic and anticyclonic activity of water masses on hydrophysical, hydrochemical, and hydrobiological parameters in the southern part of the Black Sea in September 1996

Characteristics of the spatial structure of vertical synoptic currents were calculated from data of the density field surveys in order to estimate their influence on distribution of chlorophyll a concentration. Comparisons of chlorophyll concentration and vertical currents were implemented for two multidisciplinary surveys in the Black Sea carried out in summer, 1991 and in winter, 1994. The results showed qualitative and quantitative indications of coincidence of characteristics cited and, in particular, significant positive values of the correlation coefficient (0.65 for the summer survey and 0.83 for the winter one).

Diatoms on the lower surface of Arctic sea ice and hydrochemical parameters in the water-ice layer

Morphology, ecology, range and species composition of diatom algae mass accumulations that are biotypically associated with the lower surface of Arctic sea ice are discussed. Materials were obtained by skindivers in the Central Arctic Basin at drift stations SP-23 in August 1977 and SP-22 in July 1980.

Major, trace and rare earth elements and minerals at DSDP Legs 69-70 Holes

We obtained major and trace element data on 113 samples from basalts drilled during DSDP Legs 69 and 70 in the Costa Rica Rift area. The majority have major and trace element characteristics typical of ocean-ridge tholeiities. Most of the basalts are relatively MgO rich (MgO > 8 wt.%) and have Mg values (MgO/MgO + 0.85FeO x 100) of about 53, characteristics that clearly indicate that the various magmas underwent only a small amount of crystal fractionation before being erupted onto the seafloor. According to their normative mineralogies, the rocks are olivine tholeiites. A few samples plot close to the diopside-hypersthene join of the projected basalt tetrahedron. Except for basalts from two thin intervals in Hole 504B, which differ significantly from all the other basalts of the hole, practically no chemical downhole variation could be established. In the two exceptional intervals, both TiO2 and P2O5 contents are markedly enriched among the major oxides. The trace elements in these intervals are distinguished by relatively high contents of magmatophile elements and have flat to enriched chondrite-normalized distribution patterns of light rare earth elements (LREE). Most of the rocks outside these intervals are strongly depleted in large-ionlithophile (LIL) elements and LREE. We offer no satisfactory hypothesis for the origin of these basalts at this time. They might have originated within pockets of mantle materials that were more primitive than the LIL-element-depleted magmas that were the source of the other basalts. A significant change with depth in the type of alteration occurs in the 561 meters of basalt cored in Hole 504B. According to the behavior of such alteration-sensitive species as K2O, H2O-, CO2, S, Tl, and the iron oxidation ratio, the alteration is oxidative in the upper part and nonoxidative or even reducing in the lower part. The oxidative alteration may have resulted from low temperature basalt/seawater interaction, whereas hydrothermal solutions may be responsible for the nonoxidative alteration.

Seawater carbonate chemistry and calcification rate in flume experiment

Ocean acidification (OA) poses a severe threat to tropical coral reefs, yet much of what is know about these effects comes from individual corals and algae incubated in isolation under high pCO2. Studies of similar effects on coral reef communities are scarce. To investigate the response of coral reef communities to OA, we used large outdoor flumes in which communities composed of calcified algae, corals, and sediment were combined to match the percentage cover of benthic communities in the shallow back reef of Moorea, French Polynesia. Reef communities in the flumes were exposed to ambient (400 ?atm) and high pCO2 (1300 ?atm) for 8 weeks, and calcification rates measured for the constructed communities including the sediments. Community calcification was reduced by 59% under high pCO2, with sediment dissolution explaining ~ 50% of this decrease; net calcification of corals and calcified algae remained positive but was reduced by 29% under elevated pCO2. These results show that, despite the capacity of coral reef calcifiers to maintain positive net accretion of calcium carbonate under OA conditions, reef communities might transition to net dissolution as pCO2 increases, particularly at night, due to enhanced sediment dissolution.

Geochemistry of surface and groundwaters from lower Tom Basin wetland, western Siberia

New data are reported on the major- and trace-component compositions of acidic and weakly acidic low-concentration wetland waters and other water types. Special attention was given to dissolved organic compounds: fulvic and humic acids, bitumens, and hydrocarbons. The first comprehensive data are presented for organic trace components in the wetland waters of western Siberia: alkanes, pentacyclic terpenoids, steranes, alkylbenzenes, naphthalenes, phenanthrenes, tetraarenes, etc.