Effects of temperature on oxygen consumption and ammonia—N excretion ofChlamys farreri

Effects of temperature on oxygen consumption rate (OCR) and ammonia—N excretion rate of scallopChlamys farreri (1.7–6.2 cm in shell height) were studied in laboratory from Dec. 30,1996 to Jan. 28,1997. Under the controlled conditions of ambient water temperature 10–31°C and salinity 32, the concentrations of dissolved oxygen and ammonia—N were determined by the Winkle method and the hypobromite method, respectively. Results showed that the OCR ranged from 1.20 mg/g (DW) · h to 5.76 mg/g (DW) · h. The OCR increased with temperature from 10°C to 23°C, but at 28°C the OCR of mature individuals decreased, and that of different size scallops reduced at 31°C. The ammonia—N excretion rate ranged from 113.03 μg NH₄-N/g (DW) · h to 486.63 μg NH₄-N/g (DW) · h, and increased with temperature from 10°C to 31°C. Contribution No.3180 from the Institute of Oceanology, Chinese Academy of Sciences. This work was supported by the National Commission of Science and Technology of China, Grant No.96-922-02-04.     

IMPACT OF STARVATION ON SURVIVAL，MEAT CONDITION AND METABOLISM OF CHLAMYS FARRERI

The effects of 60-day starvation on survival rate. condition index (CI) , changes ofnutrient composition of different tissues, respiration and excretion of scallop ChlartnCs farreri were studiedin laboratory from Oct. 17 to Dec. 15 ,1997. Two groups (control and starvation with 200 individualseach) were cultured in two 2 m3 tanks, with 31 to 32 salinity water at 1 7 “C . Starvation effects were mea-sured alter 1 0, 20, 40 and 60 days. There was no mass mortality of scallops cf the two tanks and survivalrates of the control and starvation groups were 93 .5 % and 92.0 %, respectively. Starvation had strongeffect on the meat condition of the scallops, especially after 10 days; when relative lipid percentagedropped sharply while relative protein percentage increased. The impact of starvation on the oxygen consumption mtc (OCR) and the ammonia-N cxcretion mtc (AER) was obvious.     

Oxygen consumption and ammonia-N excretion of Meretrix meretrix in different temperature and salinity

Effects of temperatures and salinities on oxygen consumption and ammonia-N excretion rate of clamMeretrix meretrix were studied in laboratory from Oct. 2003 to Jan. 2004. Two schemes were designed in incremented temperature at 10, 15, 20, 25°C at 31.5 salinity and in incremented salinity at 16.0, 21.0, 26.0, 31.5, 36.0, and 41.0 at 20°C, all for 8–10 days. From 10 to 25°C, both respiration and excretion rate were increased. One-way ANOVA analysis demonstrated significant difference (P<0.01) in physiological parameters in this temperature range except between 15 and 20°C. The highestQ ₁₀ thermal coefficient value (12.27) was acquired between 10 and 15°C, and about 1 between 15 and 20°C, indicatingM. meretrix could well acclimate to temperature changes in this range. Salinity also had significant effects on respiration and excretion rate (P<0.05). The highest values of respiration and excretion rate ofM. meretrix were recorded at 16.0 salinity (20°C). These two physiological parameters decreased as salinity increased until reached the minimumQ ₁₀ value at 31.5 (20°C), then again, these parameters increased with increasing salinity from 31.5 to 41.0.M. meretrix can catabolize body protein to cope with osmotic pressure stress when environmental salinity is away from its optimal range. No significant difference was observed between 26.0 and 36.0 in salinity (P>0.05), suggesting that a best metabolic salinity range for this species is between 26.0 and 36.0. This work is supported by National High-Tech R & D Program of China. (863 Program) (2002AA603014).     

Production of bioplastics and hydrogen gas by photosynthetic microorganisms

Experiments on salimity tolerance of embryos and larvae of the southern bay scallopArgopecten irradians concentricus Say under controlled temperature of 28°C showed that although the eggs were fertilized and cleaved at salinity 18.1–37.4, they could further develop into normal D-shaped larvae only at salinity 23.4–36.1, while the trochophore larvae could develop into normal D—shaped larvae at salinity 22.1–39.9. For 72 hours, the larvae could tolerate salinity of 18.4–43.9, the salinity favoring growth was 19.8–42.4; the suitable range was 21–36, and the optimum at about 28. They metamorphosed at salinity 18.9–43.5, optimally at 24–32. Contribution No. 3301 from the Institute of Oceanology, Chinese Academy of Sciences. The research was supported by the National Climbing Project B(PDB6-3-2).     

Effects of salinity, light and temperature on growth rates of two species of Gracilaria （Rhodophyta）

Effects of temperature, salinity and light intensity on growth rates of Gracilaria lichenoides and G. tenuistipitata var. liui Zhang et Xia were tested. Eight to ten levels of each factor were first tested separately. The best growth rate was obtained under the conditions of 32°C, 30 and 240 μmol/(m²·s) for G. lichenoides, and 24°C, 20 and 200 μmol/(m²·s) for G. tenuistipitata, respectively. Then a uniform design was used to evaluate the optimal combinations of the three factors. The best conditions for the highest daily specific growth rates (% increase in wet weight) are determined to be 31.30°C, 32.10, and 287.23 μmol/(m²·s) for G. lichenoides (16.26%/d), and 25.38°C, 21.10, and 229.07 μmol/(m²·s) for G. tenuistipitata (14.83%/d), respectively. Supported by the 908 Special Program (908-02-04-07), the National Basic Research Program of China (973 Program, No. 2006CB400608), and K. C. Wong Magna Fund in Ningbo University     

Allelopathic effects of macroalga <Emphasis Type="Italic">Corallina pilulifera</Emphasis> on the red-tide forming alga <Emphasis Type="Italic">Heterosigma akashiwo</Emphasis> under laboratory conditions

Over the past few years, harmful algal blooms (HABs), such as red tides, have been frequently observed in coastal zones worldwide. The natural allelopathic interactions among macroalgae and red tide microalgae can alter the structure and succession of aquatic ecosystems. We investigated the influence of four environmental factors (temperature, salinity, light, and pH) on the allelopathic effects of the macroalgae Corallina pilulifera on red-tide forming Heterosigma akashiwo under laboratory conditions. Each of the factors had four levels: temperature (15, 20, 25, and 30°C), salinity (10, 20, 30, and 40), light (20, 100, 200 and 400 μmol/(m²?s)), and pH (5.5, 7, 8.5, and 10. Two-factor experiments were designed for each two environmental factors, with six combination treatments (temperature-salinity, temperature-light, temperature-pH, salinity-light, salinity-pH, and light-pH). Results showed that the allelopathic effect was significantly influenced by temperature, salinity, light, and pH. As single factors, the low temperature (15°C), low salinity (10), high-intensity light (400 μmol/(m²?s)), and high pH (10) treatments substantially enhanced the allelopathic effect. The strongest allelopathic effect of C. pilulifera on H. akashiwo was observed under the following treatments: 15°C and salinity of 40, 25°C and pH 10, 25°C with medium- to high-intensity light at 200–400 μmol/(m 2 ?s), 400 μmol/(m²?s) and salinity of 10, 400 μmol/(m²?s) and pH 10, and pH 10 with a salinity of 40.     

COMBINED EFFECTS OF TEMPERATURE, IRRADIANCE AND SALINITY ON GROWTH OF DIATOM SKELETONEMA COSTATUM

3-factor experiment was used to study the combined effects of temperature, irradiance and salinity on the growth of an HAB species diatomSkeletonema costatum (Grev.) Cleve. The results showed that temperature (12, 19, 25, 32 °C), irradiance (0.02, 0.08, 0.3, 1.6)×10¹⁶ quanta/(s·cm²)) and salinity (10, 18, 25, 30, 35) significantly influenced the growth of this species. There were interactive effects between any two of and among all three physical factors on the growth. In the experiment, the most optimal growth condition forS. costatum was temperature of 25°C, salinity of 18–35 and irradiance of 1.6×10¹⁶ quanta/(s·cm²). The results indicatedS. costatum could divide at higher rate and were more likely to bloom under high temperature and high illumination from spring to fall. It was able to distribute widely in ocean and estuary due to its adaptation to a wide range of salinities. This study was supported by the PREPP and National Key Basic Research Project (2001CB4097) NNSFC No. 39950001, 20177023, 49576301, 49906007 and KZCX2-206.     

盐度和体质量对波纹龙虾耗氧率和排氨率的影响

利用室内实验生态学方法研究不同盐度和体质量对波纹龙虾的呼吸和排泄的影响.结果表明:不同盐度和体质量对波纹龙虾耗氧率和排氨率有显著影响(p <0.05).盐度为18~34时,波纹龙虾的耗氧率和排氨率先下降再升高,盐度26和30时较小,耗氧率分别为0.1305±0.0105 mg/(g·h)和0.1314±0.0052 mg/(g·h),排氨率分别为0.1733±0.0039 mg/(g·h)和0.1724±0.0044 mg/(g·h).波纹龙虾耗氧量(MO)和排氨量(MN)与体质量(m)呈正相关,而耗氧率(RO)和排氨率(RN)与体质量呈负相关,其关系式可表示为:MO =1.4921 m 0.4190和MN=1.1295 m 0.6988;RO=2.9333 m -0.7343和RN=1.1291 m -0.3011.     

波纹龙虾胚胎对五种生态因子的适应性

【目的】研究波纹龙虾(Panulirus homarus)胚胎对生态因子的耐受能力,为龙虾繁殖提供数据。【方法】采用封闭静水实验方法和常规生物急性毒性实验法。在温度(30±0.5)℃,盐度30,pH(8.10±0.1)和溶解氧(DO)为(5.0±0.5)mg/L条件下,分别进行温度、盐度、pH的骤变和渐变对波纹龙虾胚胎存活影响研究;根据急性毒性预实验结果设置等对数间距浓度值,进行氨氮和亚硝酸盐氮对波纹龙虾胚胎的急性毒性实验。【结果与结论】波纹龙虾胚胎发育的温度、盐度和pH耐受范围分别为7~36℃、15~45和5.8~9.4;波纹龙虾胚胎适宜温度为15~30℃,适宜盐度为30~35,适宜pH为7.0~8.5;氨氮和亚硝酸盐氮毒性效应与浓度和暴露时间呈正相关。氨氮和亚硝酸盐氮暴露24~96 h,波纹龙虾胚胎存活率组间存在显著性差异(P<0.05)。氨氮对波纹龙虾胚胎24、48、72和96 h的半致死浓度(LC₅₀)分别是180.46、61.11、41.87、26.58 mg/L,安全浓度(SC)为2.66 mg/L;亚硝酸盐氮对波纹龙虾胚胎24、48、72和96 h的LC₅₀分别是839.50、423.75、214.48、135.41 mg/L,SC为13.54 mg/L。     

Metabolism of polychaete Neanthes japonica Izuka： relations to temperature, salinity and body weight

Polychaete Neanthes japonica is a species geographically specific in China and Japan with important scientific implication and commercial value. In this study, the relations of body weight, salinity and temperature to oxygen consumption and ammonia excretion of N. japonica were determined. Three different groups in body weight (large: 2.34±0.36 g, middle: 1.50±0.21 g and small: 0.62±0.12 g) were set for all experiments. Results show that the body weight is negatively related to the rates of oxygen consumption and ammonia excretion; and the relationship is significant. The oxygen consumption and ammonia excretion at 24°C decreased at salinity from 5 to 30 and increased above 30, indicating that both lower and higher salinity are adverse and certain degree of salinity stress is necessary for enhancing the energy demand. At salinity 30, rising temperature from 18°C to 30°C, the oxygen consumption increased before 27°C and then decreased. However, the relation of ammonia excretion and temperature seems more complex. Two-way ANOVA shows that salinity, temperature and body weight all have a significant effect on the oxygen consumption and ammonia excretion of the worm. Moreover, interaction between salinity/temperature and body weight is also significant. O:N (oxygen/nitrogen) ratio varies greatly in this case from 5.97 to 463.22, indicating that N. japonica can regulate the type of metabolic substrate against environment changes. Supported by the National Natural Science Foundation of China (No. 30490233) and the Three-Gorge Project and the Estuarine Environment (No. SX2004-018) from the Three Gorges Project Construction Committee     

THE DISTRIBUTION PATTERNS OF BACTERIA,ATP AND THE RELATIONS WITH RESPIRATION RATES AND PHYTOPLANKTON IN THE CHANGJIANG ESTUARY AND ITS ADJACENT EAST CHINA SEA

Two cruises were conducted in January and July 1986 in the Changjiang (Yangtse River) Estuary and its adjacent East China Sea (30°45′ -32°00′N,121°00′-124°00′E). Direct epifluorescence counts of planktonic bacteria and determinations of ATP concentrations were made. Subsamples were taken for measurement of oxygen consumption rates and chlorophyll concentrations.Bacteria and ATP concentrations were higher in summer than in winter, highest in the river and the river mouth, and gradually lower offshore. The bacteria number was correlated positively with suspended matter, nitrates and oxygen consumption rates, and negatively with salinity.In winter bacteria were the main contributors of ATP and the main consumers of dissolved oxygen in the whole studied area. In summer two maxima of ATP were found along the salinity gradient. The first one which coincided with the peak of turbidity near the river mouth was attributed to bacte -ria, and the second which occurred in the waters with a salinity range be     

Effect of temperature under unfavourable conditions on oxygen uptake of larval herring,Clupea harengus

Oxygen uptake under starvation and short periods of sudden temperature change was measured for larval herring (Clupea harengus L.) reared at average temperature of 7.3, 11 and 12.9°C. Larval stages between first feeding and premetamorphosis were used. For comparison, the routine oxygen uptake (ROU) was also investigated and followed the relationshipQ=0.974+0.174tW ^−0.210, whereQ is in μg/(mg·h),W is dry body weight in mg andt is temperature in °C. The oxygen uptake under starvation (SOU, deprived of food for 24 h) was different from the routine when the larval dry weight was less than 0.6–0.8 mg; it increased with temperature and body weight giving the relationshipQ=1.568+0.110tW ^0.380; if the larval dry weight was more than 0.6–0.8 mg, it reverted to the norm (Q=1.704+0.078tW ^−0.349). The oxygen uptake was tested in short periods (3 h) of sudden temperature changes in six groups: 7.3 to 11, 7.3 to 12.9, 11 to 7.3, 11 to 12.9, 12.9 to 7.3 and 1.29 to 11°C. The oxygen uptake in the 7.3 to 12.9 and 12.9 to 7.3°C groups varied in a way similar to that of the larvae under starvation. The other four groups' oxygen uptake were more or less normal.     

Effects of temperature and salinity on the development of embryos and larvae of the veined rapa whelk Rapana venosa （Valenciennes, 1846）

The major population of the veined rapa whelk Rapana venosa(Valenciennes, 1846), which is an important fishery resource, is facing a large decline in China. We studied the effects of incubation temperature(16–34℃ at salinity 30) and salinity(5–45 at 25℃) on the incubation period and subsequent larval development. In the temperature experiment, the shortest incubation period was 12 days at 34℃, the lower temperature limit was 16℃, the longest mean shell length(1 193±17 μm) occurred at 25℃ and the highest survival rate 72.28%±5.62% was observed at 28℃. In the salinity experiment, the shortest incubation period was 15 days at 25. The salinity tolerance range was 15–40, the longest mean shell length(855±9 μm) and the highest survival rate 72.93%±4.85% were both observed at 35. This study demonstrated that, during the egg–mass stage, temperature and salinity regimes infl uence later growth and survival of larvae. These observations deepen our understanding of the ecology and conservation of natural populations of Rapana venosa.     

Determination of the Current System on Isopycnal Surface Between Mindanao and New Guinea from GDEM

1 .INTRODUCTIONThewesternequatorialPacific ,particularlythesouthernmostPhilippineSea ,wascalled“watermasscrossroads”byFineetal.(1 994 )duetotheconfluencethereofseveralwatermassesfromhigherlatitudesofbothhemispheres (Wyrtki,1 96 1 ;Fineetal.,1 994 ) .Fineetal.(1 994 )de picted (Fig .1 )majorcurrentsintheIndonesianregion .AfterencounteringthewesternboundaryalongthePhilippinecoast,theNorthEquatorialCur rent (NEC)bifurcatesintothenorthwardflowingKuroshioandthesouthwardflowingMindanao…     

Response of Yesso scallop Patinopecten yessoensis to acute temperature challenge: physiological and biochemical parameters

Water temperature is generally considered to be a major factor affecting the physiological and biochemical activities of marine bivalves. Here, the physiological and biochemical responses of Yesso scallop, Patinopecten yessoensis, to acute water temperature changes in summer were studied. Scallops were transferred directly to a lower temperature (T_dec treatment) (from 23°C to 15°C) or to a higher temperature (T_dec treatment) (from 15°C to 23°C) for 72 h, respectively. Results showed that the oxygen consumption and ammonia-N excretion rates of P. yessoensis decreased significantly in the T_dec treatment but increased dramatically at 6 h in the T_dec treatment (P <0.05). In the T dec treatment, hepatopancreas antioxidant enzyme activities, superoxide dismutase (SOD) and catalase (CAT) activities, increased substantially within 72 h (P <0.05). However, a significant decrease in CAT activity was found at 12 h in the T_dec treatment (P <0.01). A significant enhancement of acid phosphatase (ACP) activity and malondialdehyde (MDA) content was detected when scallops were acutely exposed to a temperature of 15°C. The levels of Cu/Zn-SOD gene expression in their gills up-regulated significantly in response to acute temperature changes (P <0.01). These data suggest that acute temperature change affects physiological and biochemical functions, and improve our knowledge of P. yessoensis under conditions of thermal stress.

     

Tetraploid induction by inhibiting mitosis I in scallopChlamys farreri

Tetraploid induction was carried out by inhibiting mitosis I in fertilized eggs ofChlamys farreri. Mitosis I was blocked with cold shock (5–7°C), Cytochalasin B (0.75 mg/L) and 6-dimethylaminopurine (6-DMAP) (60–75 mg/L) when 60% fertilized eggs released polar body II at 20°C. At 4-cells embryo stage, the ploidy was determined by counting chromosome number. In control groups, most embryos were diploids (72.22%) and aneuploids (24.78%). In Cytochalasin B, cold shock and 6-DMAP treated groups, tetraploids were respectively 10.51%, 4.08%, and 13.34%; aneuploids were 43.10%, 35.93% and 29.16%, and triploids were 7.84%, 8.52% and 18.33%. At D-larva stage, ploidy was determined by flow cytometry (FCM). The ploidy analysis of day 2 larvae showed diploids in control group and also in three treated groups. Juvenile scallops (0.2–0.3cm) which were harvested in two control groups and two CB treated groups were all diploids through checking ploidy individually by FCM. Contribution No. 3648 from the Institute of Oceanology, Chinese Academy of Sciences. Contribution No. 238 from the Experimental Marine Biology Laboratory, Chinese Academy of Sciences. Project funded by grant (No. 819-01-07) from the Chinese Science and Technology Ministry and also by “Hundred Talents Plan” grant from the Chinese Academy of Sciences.     

Variations in retention efficiency of bivalves to different concentrations and organic content of suspended particles

Retention efficiencies (RE) of scallop (Chlamys farreri), oyster (Crassostrea gigas) and mussel (Mytilus edulis) in a flow-through system were measured to understand the short-term response to various particle and organic matter concentrations. By comparing the RE of C. farreri with that of C. gigas and M. edulis, we gained further knowledge on the feeding physiological characteristics of C. farreri and ascertained the possible cause of high summer mortalities of this species. The experimental feeding conditions included natural differences in the abundance and composition of suspended seston, as well as conditions in which seston abundance and composition were manipulated by adding natural silt or cultured microalgae. The results show that in natural sea water, the minimum particle size for maximal retention in M. edulis, C. gigas and C. farreri was approximately 4, 6, and 8 μm, respectively; the RE of 2-μm (equivalent spherical diameter) particles was 17%, 19%, and 8%, respectively; and the relative standardized RE was 58%, 49%, and 18%, respectively. In C. gigas and M. edulis, the minimal particle size for maximal retention did not change with food quality (organic content). C. farreri was more sensitive to fluctuations in particle concentration and organic content. With particle concentration increase, the minimal particle size for maximal retention in scallop shifted to large particles and the RE for 2-μm particle decreased from 8% in natural seawater to 1.6%–6% in silt-enriched groups. With organic content increase, the minimal particle size for maximal retention shifted from 8 to 5 μm in natural seawater.Variation in RE of C. farreri with food conditions and the relationship between lower RE and smaller particle size may hamper C. farreri from food taking due to the decrease in the size distribution of phytoplankton in Sungo Bay.     

Diel variation in metabolism and ammonia excretion of <Emphasis Type="Italic">Marphysa sanguinea</Emphasis> (Polychaeta: Eunicidae)

Polychaetes provide an excellent food resource for fish and represent the dominant zoobenthos in marine ecosystems. Diel variation in the rates of metabolism and ammonia-N excretion of Marphysa sanguinea were studied. The worms were grouped according to their wet body weight into small (S; 1.24±0.06 g), medium (M; 4.00±0.30 g), and large (L; 8.54±1.08 g) categories. Their weight-specific metabolic rates, based on aerobic respiration (R), were measured at 16°C (±0.2°C) and classed as either routine (R _R) or standard (R _S) rates. Both respiration types decreased with increasing body weight. Respiration was described by R = a W ^b, where b was -0.400 9 and -0.532 0 for R _R and R _S, respectively. Diurnal changes in R _S for each group was relatively flat, with a slightly increasing trend with time, but was relatively stable as a whole. R _R of the diurnal variation of worms was higher than R S, but both had similar overall trends. The peak values of specific dynamic action (SDA) (R _SDA) in the S, M, and L groups were 2.704, 1.149, and 0.682 mg/(g?h), respectively. The durations of SDA were 13, 6, and 6 h, respectively and the energy expenditures of SDA were 377.98, 117.34, and 74.94 J/g, respectively. These data indicate that the metabolic rates were higher in smaller individuals, which is advantageous for their rapid growth.     

Polyculture of scallopChlamys farreri and kelpLaminaria japonica in Sungo Bay

Several polyculture models of scallopChlamys farreri and kelpLaminaria japonica currently employed in Sungo Bay and other parts of northern China are described in this paper. Economic benefits of different polyculture models are analysed based on the growth rate, culture density and market price. In addition, site selection, critical environmental conditions and polyculture problems are discussed in detail. This project was funded by the International Development and Research Centre (IDRC), Canada, and the National Committee of Science and Technology of China.     

Molecular identification and culture trials of Eutreptiella gymnastica (Eutreptiales, Euglenophyceae)

During a survey for marine microalgal resources, we isolated a rare marine euglenoid from the coastal waters of Qingdao, China in 2009, and established a pure culture. Electron microscopic and molecular phylogenetic (18S rDNA and 16S rDNA sequences) analyses revealed a close affinity with Eutreptiella gymnastica, a bloom-forming species. Different culture conditions were monitored to understand optimal E. gymnastica growth characteristics. The optimal growth conditions in a batch culture of this isolate were 20°C, 160 μmol photons/(m2×s) of white light, and a salinity of 10-31. Nutrient experiments demonstrated that growth increased dramatically with a phosphorus concentration greater than 72 μmol/L. Understanding the effect of culture conditions on E. gymnastica may help understanding the blooming mechanism of this alga in its natural environment.