Diurnal variations of some physico-chemical factors in the Zuari estuary of Goa

90-93Diurnal variations of temperature, salinity, dissolved oxygen and nutrient salts at two locations in the Zuari estuary were studied in different seasons as a part of the project on the Ecology of Mandovi and Zuari estuaries with special reference to changes in living resources. Marked changes were noted in all the parameters. Temperature and salinity variations followed the tidal rhythm in all the seasons. Except silicates the other chemical factors, viz, dissolved oxygen, phosphates and nitrates, showed distribution independent of tidal variations, the silicate behaved more as a non-conservative factor within the estuary. Probably reasons and significance of the variations were discussed

Application of vertical advection-diffusion model for studying CO₂and O₂profiles in Central Arabian Sea

172-175The vertical advection-diffusion model proposed by Craig has been applied to the study of CO2 and O2 profiles in Central Arabian Sea. Distributions of total CO2 and O2 are explained better by expressions involving exponential rates than those based on constant production rates

TCO₂ - O₂ correlation in the Central Arabian Sea

136-138Linear relationship exists between total CO2 [TCO2] and observed dissolved oxygen in the Central Arabian Sea, which agrees well with the organic decomposition model of Redfield, Ketchum and Richards (The Sea edited by M.N. Hill, Vol. 2, 1963, P26). Ratios of D C/D O obtained for 13 stations in this region are in good agreement with the theoretical value. Processes other than oxidations effecting TCO2 are considered for correction to obtain the linear correlation

Studies on carbon dioxide system in Central Arabian Sea

176-177Data on pH and total alkalinity have been utilised in the study of carbon dioxide and its species in Central Arabian Sea. Total carbon dioxide and partial pressure of carbon dioxide remain fairly constant in the upper layers but increase significantly with depth. Bicarbonate ion is quantitatively the major component of the carbon dioxide system. The observed vertical distributions are discussed in terms of biological and geochemical processes in the sea

Seasonal variations in halides in marine brown algae from Porbandar and Okha coasts (NW coast of India)

137-141Seasonal variation of halides and their ratios were estimated in three brown algae, namely Cystoseira indica, Sargassum tenerrimum and S. johnstonii from Porbandar and Okha coasts. Halides were found to be higher in early stages of growth. TheBr:F ratio was higher in reproductive stage indicating that algae tend to accumulate Br compared to F during this stage than at early and senescent stages; though Br level in ambient medium is not a limiting factor. Matrix analysis of DPEF (differential percentage of enrichment factor) of halides shows that the tissue concentration of each halide was independent of other halides accumulation. The extent of bioaccumulation could be related to intrinsic property such as kappa spec (spectroscopic electronegativity) of each halide. The kappa spec was found to control the relative enrichment of elements (halides). From the available data oh Indian marine algae, the stoichiometric relationship of iodine with respect to the bulk constituents was found to be 7900:531:16:1 for C:N:P:I which differs from that of Redfield ratio

Seasonal variations in Na, K, Mg and Ca and charge balance in marine brown algae from Saurashtra coast (NW coast of India)

41-45Seasonal variation of Na, K, Mg and Ca were estimated in Cystoseira indica, Sargassum tenerrimum and S. johnstonii. Abundance of these elements were higher during the rapid growth stage but decreased subsequently. Monovalent cations (Na + K) strongly correlated with Cl content suggesting that these cations were balanced by chloride ions. Divalent cations (Ca + Mg) seem to be balanced by the anion sulphate. Ash content of the algae was accounted by these major cations and anions. Charge equivalent among these cations and anions was not balanced in the ash of the algae. The cations charge equivalence could be balanced by chloride and sulphate in addition to the anions of C, N and P origin (OH-, RCOO(-) H2PO3- etc.). A significant correlation (P <0.001) between per cent of negative ions deficit and per cent of excessive unbalanced cations was observed. Perhaps 9-32% (on large data base upto 60%) of the organic matter participate in charge balance of cations. Intertidal position seemed to affect the osmoregulation process

Boron chemistry in relation to its variations in eastern Arabian Sea

178-182Boron varied from 3.96 to 5.3 mg.kg-1 in the coastal and from 3 to 4.74 mg.kg-1 in the offshore waters. B/Cl showed a wide variation from 0.202 to 0.269 in the coastal region while significantly low ratios (< 0.2) to as high as 0.238 were observed in the offshore waters. Percent addition and removal of boron computed by taking into consideration the world average B/Cl of 0.232 indicated an addition up to 16% and removal up to 11.65% resulting in a net addition of boron to the coastal waters. At few stations boron was found to be released from the oxidation of organic matter while its removal was attributed to the net effects of suspended solids and the primary productivity. In the offshore waters, significant decrease of boron in the euphotic zone was mainly due to biological removal during high productivity

Distribution of CO₂ species in seawater of central west coast of India

239-241During the 89 cruise of R V Gaveshani water samples were collected at 5 stations from different depths to study to distribution of CO2 and CO2- bearing species. Total CO2 (TCO2), PCO, HCO, and CO were computed from salinity, temperature, pH and total alkalinity measurements. In deep water stations (0-1500 m), there was a decrease of TCO2 from surface to 150 m depth whereas in shallow water stations (0-100 m) it was higher at the surface layers. Partial pressure of CO2 was more or less constant in the upper layers up to 100 m and then gradually increased reaching maximum levels up to 1500 m. In general contribution of HCO towards TCO content was about 80-90% while that of CO was 2-12%