A Kinetic Spectrophotometric Method for the Determination of Iron （Ⅲ） in Water Samples

A new kinetic spectrophotometric method has been developed for the determination of iron (Ⅲ). The method is based on the catalytic effect of iron (Ⅲ) on the oxidation of weak acid brilliant blue dye (RAWL) by KIO4 in acid medium. The advantages of the proposed method are that it is sensitive, accurate, rapid, inexpensive, can be operated under room temperature and has a large determination concentration range compared to other techniques. The obtained optimum conditions are pH 3.15, RAWL (200 mgL-1) 5.00mL, Potassium periodate solution (0.01 molL-1) 0.30mL, phenanthroline (0.02molL-1) 1.00mL, reaction temperature 25℃ and reaction time 7 miu. With this method iron could quantitively be determined in the range 0.00-0.02 mgL-1, the detection limit being 4.10×10-10mL-1. The relative standard deviations (RSD) in five replicate determinations for 3 μgL-1 and 5μgL-1 iron (Ⅲ) are 3.1% and 1.9%, respectively. The method has been applied to the determination of iron (Ⅲ) in tap water samples and seawater samples (from the South China Sea), the recovery rates being 98.0% and 100.5%, respectively.     

Effects of Nutritional Factors on the Growth and Heterotrophic Eicosapentaenoic Acid Production of Diatom Nitzschia laevis

The effects of several nutritional factors on the growth and eicosapentaenoic acid (EPA) production of diatom Nitzschia laevis were studied. 4 LDM (quadrupled concentration of the nutrient salt) was the optimal concentration of nutrient salt for the growth and EPA production ofN. laevis. The growth ofN. laevis was inhibited when the glucose concentration was either lower than 10gL-1 or higher than 15gL-1. Both sodium nitrate and urea were good nitrogen sources for the growth and EPA production, while ammonium chloride seriously decreased the dry cell weight (DW) and the EPA content. Silicate seriously influenced the growth of N. laevis. The maximum DW of 2.34gL-1 was obtained in the presence of 150 mgL-1 Na2SiO3·9H2O. The EPA content remained almost the same when the silicate concentration was lower than 150 mgL-1; however, higher silicate concentrations resulted in a steady de- crease of EPA content. Low medium salinity (≤29) did not seem to influence the DW of N. laevis, and high salinity resulted in a decrease of DW. The highest EPA content (4.08%) and yield (110 mgL-1) were observed at the salinity of 36 and 29, respectively.     

Bioflocculant Produced by Klebsiella sp. MYC and Its Application in the li＇eatment of Oil-field Produced Water

Seventy-nine strains of bioflocculant-producing bacteria were isolated from 3 activated sludge samples. Among them, strain MYC was found to have the highest and stable flocculating rate for both kaolin clay suspension and oil-field produced water. The bacterial strain was identified as Klebsiella sp. MYC according to its morphological and biochemical characteristics and 16SrDNA sequence. The optimal medium for bioflocculant production by this bacterial strain was composed of cane sugar 20 g L^-1, KH2PO4 2 g L^-1, K2HPO4 5 g L^- 1, （ NH4）2SO4 0.2 g L^-1, urea 0.5 g L^- 1 and yeast extract 0.5 g L^- 1, the initial pH being 5.5. When the suspension of kaolin clay was treated with0.5% of Klebsiella sp. MYC culture broth, the flocculating rate reached more than 90.0% in the presence of 500mg L^-1 CaCI2, while the flocculating rate for oil-field produced water was near 80.0% in a pH range of 7.0 - 9.0 with the separation of oil and suspended particles from the oil-field produced water under similar conditions. The environment-friendly nature of the bioflocculant and high flocculating rate of the strain make the bioflocculant produced by Klebsiella sp. MYC an attractive bioflocculant in oil-field produced water treatment.     

Acute Toxicity of Formalin to the Red-tide Dinoflageilate Prorocentrum minimum Schiller （Protozoa, Mastigophora）

The acute toxic levels of formalin to a marine red-tide dinoflagellate Prorocentrum minimum Schiller (Mastigophora, Dinoflagellida) were determined by linear regression analysis. The data obtained revealed that there is a close regression relationship between logarithmic concentrations of formalin and mortality probit scales of the organism when exposure times are 1, 2, 6, 12, 24 h. The median lethal concentrations (LC50 values) obtained from correlation analysis for these exposure times (with 95% confidence intervals), were 11.83, 6.76, 4.37, 4.27 and 3.98mgL^-1 respectively. A toxicity curve was obtained to connect the exposure time and LC50 value from the correlation between them. The results indicated that P. minimum could be killed or fixed by formalin in the concentration range of 4-12mgL^-1 within 1-24h.     

Effects of sodium nitrate and sodium acetate concentrations on the growth and fatty acid composition of <Emphasis Type="Italic">Brachiomonas submarina</Emphasis>

One isolate of Brachiomonas submarina was tested for its ability to grow heterotrophicly on 5 different organic compounds. Sodium acetate and glucose were found to be effective in supporting the growth. Sodium acetate was chosen as the organic nutrient to test the combined effects of organic and inorganic solutions on the growth and fatty acid composition of Brachiomonas submarina. The best growth rates were achieved at 3 mmol L⁻¹ CH₃COONa and 0.88 mmol L⁻¹ NaNO₃ in heterotrophic condition, and 4 mmol L⁻¹ CH₃COONa and 3.52 mmol L⁻¹ NaNO₃ in mixotrophic condition. The differences between fatty acid contents were significant. The total polyunsaturated fatty acids (T. P. U. F. As) varied from 55.79% to 67.72% in heteritrophic growth and from 52.39% to 65.55% in mixotrophic growth. It is concluded that CH₃COONa and NaNO₃ at 3 mmol L⁻¹ and 3.52 mmol L⁻¹ should respectively be used in order to achieve the highest growth rate and fatty acid content.     

Impacts of CO<Subscript>2</Subscript> enrichment on growth and photosynthesis in freshwater and marine diatoms

The physiological responses of Nitzschia palea Kvtzing, a freshwater diatom, to elevated CO2 were investigated and compared with those of a marine diatom, Chaetoceros muelleri Lemmermann previously reported. Elevated CO2 concentration to 700 μl/L increased the dissolved inorganic carbon （D!C） and lowered the pH in the cultures of N. palea, thus enhancing the growth by 4%-20% during the whole growth period. High CO2-grown N. palea cells showed lower levels of dark respiration rates and higher Ik values. Light-saturated photosynthetic rates and photosynthetic efficiencies decreased in N. palea with the doubling CO2 concentration in airflow to the bottom of cultures, although the doubling CO2 concentration in airflow to the surface cultures had few effects on these two photosynthetic parameters. N. palea cells were found to be capable of using HCO5 in addition to gaseous CO2, and the CO2 enrichment decreased their affinity for HCO5 and CO2. Although doubled CO2 level would enhance the biomass of N. patea and C. muelleri to different extents, compared with the marine diatom, it had a significant effect on the specific growth rates of N. palea. In addition, the responses of photosynthetic parameters of IV. palea to doubled CO2 concentration were almost opposite to those of C. muelleri.     

Bioaccumulation of Pb<Superscript>2+</Superscript> and its effects on growth,morphology and pigment contents of <Emphasis Type="Italic">Spirulina</Emphasis> (<Emphasis Type="Italic">Arthrospira</Emphasis>) <Emphasis Type="Italic">platensis</Emphasis>

A laboratory experiment was conducted to assess the bioaccumulation of Pb²⁺ and its effects on growth, morphology and pigment contents of Spirulina (Arthrospira) platensis. The specimen cultured in Zarrouk liquid medium was treated with various initial metal concentrations (0, 5, 10, 30, 50 and 100 μg mL⁻¹). The growth of S. platensis was adversely affected by Pb²⁺ at high concentrations (30, 50 and 100 μg mL⁻¹). However, at low concentrations (5 μg mL⁻¹), Pb²⁺ could stimulate its growth slightly. The pigment contents (chlorophyll α and β carotene) were decreased in a dose-dependent manner. The highest reductions (67% and 53% respectively in chlorophyll α and β carotene) were observed in 100 μg mL⁻¹ treatment group. The LC₅₀ (96 h) of Pb²⁺ was measured as 75.34 μg mL⁻¹. Apart from a few cases of filament breakages at elevated concentrations (50 and 100 μg mL⁻¹), morphological abnormalities are not specific. Metal bioaccumulation increased with Pb²⁺ concentrations, but decreased with exposure time. The maximum accumulated amount was 188 mg g⁻¹ dry weight. The bioconcentration factor (BCF) reached to a peak at day 2, followed by a gradual reduction for all the exposure concentrations. S. platensis is able to tolerate considerably high Pb²⁺ concentrations. Consequently it can be used as a potential species to remove heavy metal from contaminated waters.     

Immunotoxicity effect of benzo[α]pyrene on scallop Chlamys farreri

The toxic effects of benzo[α]pyrene (B[α]P) at different concentrations (0.1, 0.5, 1, 2.5 and 7.5 μgL⁻¹) on scallop (Chlamy farreri) immune system were studied. The results showed that B[α]P had significant toxic effects on the haemocyte counts, neutral red uptake, phagocytosis, bacteriolytic and antibacterial activity (P<0.05), while the seawater control and acetone control had no significant differences. The haemocyte counts, neutral red uptake, phagocytosis and bacteriolytic activity in all B[α]P treatment groups as well as antibacterial activity in groups of 0.5, 1, 2.5 and 7.5 μgL⁻¹ B[α]P decreased significantly (P<0.05). Some of these indices tended to be stable on the sixth day and others on the ninth day, and the indices showed clear time- and concentration-response to B[α]P. Bacteriolytic activity in 0.1μgL⁻¹ B[α]P treatment group and antibacterial activity in 0.1 μgL⁻¹ and 0.5 μgL- B[α]P treatment groups increased at the beginning of exposure and reached their peaks on day 1 and day 6, respectively. Following that, both activities decreased gradually and became stable after day 9. When all the indices reached stability, they were significantly lower than those in control group (P<0.05), except for antibacterial activity in 0.1 μgL⁻¹ B[α]P treatment group (P>0.05). Thus, B[α] has evident toxic effects on scallop immune system, which supports the view that a relationship exists between pollution and immunomodulation in aquatic organisms.     

Simulating carbon sequestration and GHGs emissions in <Emphasis Type="Italic">Abies fabric</Emphasis> forest on the Gongga Mountains using a biogeochemical process model Forest-DNDC

The process-oriented model Forest-DNDC describing biogeochemical cycling of C and N and GHGs （greenhouse gases） fluxes （CO2, NO and N2O） in forest ecosystems was applied to simulate carbon sequestration and GHGs emissions in Abies fabric forest of the Gongga Mountains at southeastern edge of the Tibetan Plateau. The results indicated that the simulated gross primary production （GPP） of Abies fabric forest was strongly affected by temperature. The annual total GPP was 24,245.3 kg C ha^-1 yr^-1 for 2005 and 26,318.8 kg C ha^-1 yr^-1 for 2006, respectively. The annual total net primary production （NPP） was 5,935.5 and 4,882.2 kg C ha^-1 yr^-1 for 2005 and 2006, and the annual total net ecosystem production （NEP） was 4,815.4 and 3,512.8 kg C ha^-1 yr^-1 for 2005 and 2006, respectively. The simulated seasonal variation in CO2 emissions generally followed the seasonal variations in temperature and precipitation. The annual total CO2 emissions were 3,109.0 and 4,821.0 kg C ha^-1 yr^-1 for 2005 and 2006, the simulated annual total N2O emissions from forest soil were 1.47 and 1.36 kg N ha^-1 yr^-1 for 2005 and 2006, and the annual total NO emissions were 0.09 and o.12 kg N ha^-1 yr^-1 for 2005 and 2006, respectively.     

Determination of Trace Copper （Ⅱ） in Water Samples by Kinetic-spectrophotometry

A new kinetic-spectrophotometric method is proposed for the determination of copper （ Ⅱ ）. The method is based on the catalytic effect of copper （ Ⅱ ） on the oxidation of weak acid brilliant blue dye （RAWL） by hydrogen peroxide. The copper （ Ⅱ ） can be determined spectrophotometrically by measuring the decrease of absorbance of RAWL at λ = 626 nm using the fix-time method. The optimum reaction conditions are as follows： pH 7.20, buffer solution NaOH-KH2PO4, RAWL （200 mgL-1） 5.00 mL, H2O2 （30%） 0.50 mL, reaction temperature 80 ？？ and reaction time 20 min. The linear range of this method is between 0 μg L^-1 and 12 μg L^-1 and the limit of detection is 0.011 μg L-1, the relative standard deviation （RSD） in five replicate determinations for 2 and 8 μg L-1 copper （ Ⅱ ） are 3.2% and 2.3%, respectively. Twenty ions do not interfere in the determination of copper （ Ⅱ ）. The method has been applied satisfactorily to the determination of copper （ Ⅱ ） in freshwater samples （tap water and Yellow River water from Lijin, Shandong, China） and seawater samples （from the South China Sea）, the recovery rates are 98.0%, 102.5% and 96.0%, respectively.     

Monthly Changes of Glycogen, Lipid and Free Amino Acid of Oyster

Monthly difference of the chemical composition of oyster cultured along the eastern coast of Shandong Province was analyzed. The components analyzed included glycogen, fatty acid and free amino acid （FAA）. The content of glycogen was high in January and March （2.89 and 2.82 g（100 g） ^-1 on average, respectively） and low in October （2.07g（100g）^- 1 on average）. The low content of neutral lipids in October reflected a relatively poor nutritional value of oyster （1.42 g（ 100 g）^- 1 on average）. The main fatty acids of oyster were palmitic acid （16：0）, oleic acid （18： 1）, eicosapentaenoic acid （EPA, 20： 5（0 3） and docosahexaenoic acid （DHA, 22：6（0 3）. The major FAAs of oyster were Taurine, Glutamicacid, Glycin, Alanine, Arginine and Proline. Taurine was the most abundant FAA with its content ranging from 603 mg（100 g） ^-1 to 1 139 mg（ 100 g） ^-1. The high contents of glycogen, polyunsaturated fatty acid and FAA showed that oyster cultured along the eastern coast of Shandong Province was nutritionally good in January and March.     

Studies on culture conditions of benthic diatoms for feeding abalone

Effects of salinity, pH, nitrogenous and phosphate nutrients on the growth rate of four species of benthic diatoms were studied by using the method of in situ optical density measurement. The optimal culture conditions for the four species of diatoms are as follows: forAmphora coffeaeformis, s 35; pH 8.5; NO₃ ⁻−N 1.54, NH₄ ⁺−N, 7.0; CO (NH₂)₂−N, 2.5 (mg/L); PO₄ ³⁻−P 1.13 (mg/L); forCocconeis scutellum varparva, s 30; pH 8.5; NO ₃ ⁻ −N 3.08, NH ₄ ⁺ −N 3.5, CO(NH₂)₂−N 5.0 (mg/L); pO ₄ ³⁻ −P 0.283 (mg/L); forNavicula corymbosa s 25; pH 8.0; NO ₃ ⁻ −N 1.54, NH ₄ ⁺ −N 3.5 CO(NH₂)₂−N 5.0 (mg/L); PO ₄ ³⁻ −P 0.565 (mg/L); forNavicula mollis. s 25; pH 8.0; NO ₃ ⁻ −N 1.54, NH ₄ ⁺ −N 1.75, CO(NH₂)₂−N 1.25 (mg/L); PO ₄ ³⁻ −P 0.141 (mg/L). Part of the results of this paper were exchanged in the Fourth Asian Aquaculture Forum. Oct. 16–20. 1995. Beijing, P. R. China.     

Exopolysaccharide Production by Four Cyanobacterial Isolates and Preliminary Identification of These Isolates

Four marine cyanobacterial isolates, named 104, 109, 113 and 115, from marine water off China＇s coast can release a large amount of exopolysaccharide （EPS） to medium. The effects of different components in medium on EPS production by the four isolates were investigated. Under the optimal condition, the EPS released by isolates 104,109, 113 and 115 reached 7.48 g L^-1, 8.33 g L^-1, 18.26 g L^-1, and 6.78 g L^-1 within 14 d,respectively. Based on the conventional identification methods for cyanobacteria,these isolates were assigned to genus Cyanothece.     

EXAMINATION OF SILICATE LIMITATION OF PRIMARY PRODUCTION IN JIAOZHOU BAY, CHINA——I. SILICATE BEING A LIMITING FACTOR OF PHYTOPLANKTON PRIMARY PRODUCTION

Jiaozhou Bay data collected from May 1991 to February 1994, in 12 seasonal investigations, and provided the authors by the Ecological Station of Jiaozhou Bay, were analyzed to determine the spatiotemporal variations in temperature, light, nutrients (NO3^--N, NO2^--N, NH4^ -N, SIO3^2--Si, PO4^3--P), phytoplankton, and primary production in Jiaozhou Bay. The results indicated that only silicate correlated well in time and space with, and had important effects on, the characteristics, dynamic cycles and trends of, primary production in Jiaozhou Bay. The authors developed a corresponding dynamic model of primary production and silicate and water temperature. Eq. ( 1 ) of the model shows that the primary production variation is controlled by the nutrient Si and affected by water temperature; that the main factor controlling the primary production is Si; that water temperature affects the composition of the structure of phytoplankton assemblage; that the different populations of the phytoplankton assemblage occupy different ecological niches for C, the apparent ratio of conversion of silicate in seawater into phytoplankton biomas and D, the coefficient of water temperature‘s effect on phytoplankton biomass. The authors researched the silicon source of Jiaozhou Bay, the biogeochemical sediment process of the silicon, the phytoplankton predominant species and the phytoplankton structure. The authors considered silicate a limiting factor of primary production in Jiaozhou Bay, whose decreasing concentration of silicate from terrestrial source is supposedly due to dilution by current and uptake by phytoplankton; quantified the silicate assimilated by phytoplankton, the intrinsic ratio of conversion of silicon into phytoplankton biomass, the proportion of silicate uptaken by phytoplankton and diluted by current; and found that the primary production of the phytoplankton is determined by the quantity of the silicate assimilated by them. The phenomenon of apparently high plant-nutrient concentTations but low phytoplankton biomass in some waters is reasonably explained in this paper.     

The inhibitory degree between Skeletonema costatum and dinoflagllate Prorocentrum donghaiense at different concentrations of phosphate and nitrate/phosphate ratios

Interactions between Skeletonema costatum (S. costatum) and Prorocentrum donghaiense (P. donghaiiense) were inves-tigated using bi-algal cultures at different concentrations of phosphate (PO4-P) and nitrate/phosphate (N/P) ratios. Experiments were conducted under P-limited conditions and the Lotka-Volterra mathematical model was used to simulate the growth of S. costatum and P. donghaiense in the bi-algal cultures. Both of these two species were inhibited significantly in bi-algal culture. The results of the simulation showed that the inhibitory degree of S. costaum by P. donghaiense was high when the concentration of PO4-P was low (0.1μmolL-1/2 d), but that of P. donghaiense by S. costaum was high with increased PO4-P supply (0.6μmolL-1/2 d). At low concen-tration of PO4-P (0.1μmolL-1/2 d), or high concentration of PO4-P (0.6μmolL-1/2 d) with high N/P ratio (160), the interactions be-tween S. costatum and P. donghaiense were dependent on the initial cell densities of both species. At high concentration of PO4-P (0.6μmolL-1/2 d) with low N/P ratio (25 or 80), S. costatum exhibited a survival strategy superior to that of P. donghaiense. The de-gree of inhibition of P. donghaiense by S. costaum increased with elevated N/P ratio when the medium was supplemented with con-centration 0.1μmolL-1/2 d of PO4-P. The degree of inhibition to P. donghaiense by S. costaum increased with elevated N/P ratio at low concentration of PO4-P (0.1 μmolL-1/2 d). This trend was conversed at high concentration of PO4-P (0.6μmolL-1/2 d). However, the degree of inhibition of S. costaum by P. donghaiense increased with the increased N/P ratio at different PO4-P concentrations (0.1μmolL-1/2 d and 0.6μmolL-1/2 d). These results suggested that both phosphate concentration and N/P ratio affected the competition between S. costaum and P. donghaiense: P. donghaiense is more competitive in environments with low phosphate or high N/P ratio and the influence of N/P ratio on the competition was more significant with lower phosphate concentration.     

DYNAMIC CHANGES OF INORGANIC NITROGEN AND ASTAXANTI—IIN ACCUMULATION IN HAEMATOCOCCUS PLUVIALIS

This study on dynamic changes of culture color,astaxanthin and chlorophylls,inorganic N including N-NO3^-,N-NO2^- and N-NH4^ in batch culture of Haematococcus pluvialis exposed to different additive nitrate concentration showed(1)ast/chl ratio was over 0.8 for brown and red algae,but was usually less than 0.5 for green and yellow algae;(2)N-NO3^-,in general,was unstable and decreased,except for a small unexpected increase in nitrate enriched treatment groups;(3)measurable amounts of N-NO2^- and N-NH4^ were observed respectively with three change modes although no extemal nitrite and ammonia were added into the culture;(4)a non-linear correlation between ast/chl ratio(or color)changes and the levels of N-NO3^-,N-NO2^-,N-NH4^ in H.pluvialis culture;(5)up and down variation of the ast/chl ratio occurred simultaneously with a perceptible color change from yellow to brown(or red)when N-NO3^-,N-NO2^- and N-NH4^ fluctuated around 30,5,5μmol/L respectively;(6)existence of three dynamic modes of N-NO3^-,N-NO2^- and N-NH4^ changes,obviously associated with initial extemal nitrate;(7)the key level of total inorganic N concentration regulating the above physiological changes during indoor cultivation was about 50 μmol/L;and(8)0.5-10mmol/L of nitrate was theoretically conducive to cell growth in batch culture.     

Effects of temperature, salinity, light intensity, and pH on the eicosapentaenoic acid production of Pinguiococcus pyrenoidosus

The effects of temperature, light intensity, salinity, and initial pH on the growth and fatty acid composition of Pinguiococcus pyrenoidosus 2078 were studied for eicosapentaenoic acid (EPA) production potential. The fatty acid composition was assayed by gas chromatography-mass spectrometry, which indicated that the main fatty acids were C14:0, C16:0 and EPA. The highest EPA percentage 20.83% of total fatty acids was obtained at 20℃ with the temperature being set at 20, 24, and 28℃. Under different salinities and light intensities, the highest percentages of total polyunsaturated fatty acids (PUFAs) and EPA were 17.82% and 31.37% of total fatty acids, respectively, which were achieved at salinity 30 and 100μmol photon m-2s-1 illumination. The highest percentages of total PUFAs and EPA were 38.75% and 23.13% of total fatty acids, respectively, which were reached at an initial pH of 6 with the test range being from 5.0 to 9.0.     

Comparative studies of inorganic carbon utilization inEmiliania huxleyi and some non-calcifying marine microalgae

Inorganic carbon utilization in the non-calcifying marine microalgae,Nannochloropsis oculata, Phaeodactylum tricornutum andPorphyridium purpureum was compared with high- and low-calcifying strains ofEmiliania huxleyi grown in artificial seawater medium aerated with either air (0.03% V/V CO₂) or CO₂-free air. For high-calcifying strain ofE. oculata andP. tricornutem, similar growth patterns were observed in air-and CO₂-free air-grown cultures.P. purpureum showed a less final cell density in CO₂-free air than in air-grown culture. However, low-calcifying strain ofE. huxleyi was able to grow only in air-grown culture, but not in CO₂-free air-grown culture. Measurements of alkalinity, pH, concentration of dissolved inorganic carbon (DIC) and free CO₂ showed different patterns of DIC utilization. WithN. oculata, P. tricornutum andP. purpureum the pattern of DIC utilization was characterized by an increase of pH and a decrease of DIC but a constant alkalinity in the cultures aerated with air or CO₂-free air, suggesting that bicarbonate utilization was concomitant with an efflux of OH⁻. Both alkalinity and pH were maintained rather constant in air-grown culture of low-calcifying strain ofE. huxleyi, suggesting that diffusive entry of CO₂ could meet the requirement of DIC for its photosynthesis and growth. High-calcifying strain ofE. huxleyi, however, showed a pattern of decrease of alkalinity and DIC but an almost constant pH, indicating that bicarbonate was the major form of inorganic carbon utilised by this organism and bicarbonate uptake is unlikely to be accompanied by an efflux of OH⁻. The final pH values reached byN. oculata, P. tricornutum andP. purpureum in a closed system were 10.75, 10.60 and 9.85 respectively, showing that bicarbonate utilisation is concomitant with an efflux of OH⁻. While the final pH of 8.4 in high-calcifyingE. huxleyi suggests that bicarbonate utilization was not accompanied by an efflux of OH⁻. Contribution No. 3557 from the Institue of Oceanology, Chinese Academy of Sciences. This work was supported by NERC grant GRE3/7853 U. K. and partly supported by Bio-Engineering Center, SSTC 96-C01-05-01.     

FOOD SOURCES AND CARBON BUDGET OF CHINESE PRAWN PENAEUS CHINENSIS

This study deals with contribution of artificial food pellet and natural food to Chinese prawn (Penaeus orientalis) growth in a semiintensive culture pond. The prawn carbon consumption, budget, and the effects of some factors on the budget were investigated. The results showed that 26.2% of P. orientalis growth carbon came from formulated feed at the initial culture stage (when the prawns were 0.06±0.01 g in wet weight), and was 62.5% when the prawns were 9.56±1.04 g. The remaining part of the growth carbon was derived from organic fertilizer and natural food. The highest growth rate occurred at 20×10-3 salinity. Suitable salinity for culturing Chinese prawn was (20-28)×10-3.     

New discovery of coral rubbings in the north-western Gulf of Kachchh, Gujarat, Western India �� GIS based evaluation

The Gulf of Kachchh in western India, with its arid climate, large semi-diurnal tidal amplitudes, negative water balance and near-pristine water quality, is being extensively developed as oil importing bases for economic reasons in connection with its proximity to the oil exporting countries of the Middle East. Besides, new coral rubbings were sighted in Jakhau, north-western Gulf of Kachchh. Dredging in Mandvi of the north Gulf covering 3.5 km² revealed a similar assortment of live corals with their associated flora and fauna. These pioneering observations demonstrate that there exist live corals of young polyps-colony of Favia sp. belonging to the family Faviidae in the north-western Gulf of Kachchh. The environmental parameters there were carefully recorded as: surface water temperature (°C) varying from 29 to 31.8, salinity (ppt), pH, dissolved oxygen (mgL⁻¹) and total suspended solids (mgL⁻¹) in the ranges of 37–43.5, 7.7–8.45, 5.4–6.8 and 11–31, respectively.