[Temporal and spatial variations and driving factors of phytoplankton in Yongjiang River estuary]. / ç”¬æ±Ÿå£æµ®æ¸¸æ¤ç‰©æ—¶ç©ºåˆ†å¸ƒç‰¹å¾åŠé©±åŠ¨å› å­.

To explore the temporal and spatial variations in phytoplankton community in small estuaries, we collected surface water samples from Yongjiang River estuary during wet, normal, and dry seasons and determined the main driving factors of phytoplankton community. A total of 358 species belonging to nine phyla and 123 genera were identified in all seasons. During wet, normal, and dry seasons, species number was 276, 154 and 151, and the abundance was (170.45±225.43)×103, (51.92±30.28)×103 and (31.65±12.79)×103 cells·L-1, respectively. Diatoms dominated the phytoplankton community, and the main dominant species were Cyclotella meneghiniana, Skeletonema costatum, and Paralia sulcata. Shannon diversity and Pielou evenness indices decreased from inside mouth to outside mouth in wet season, but there was no obvious spatial difference in normal season or dry season. Results of non-metric multidimensional scaling analysis and analysis of similarities showed that phytoplankton community composition differed significantly among different regions (inside, at and outside mouth) and different seasons. In wet season, phytoplankton abundance was significantly positively correlated with temperature, dissolved inorganic nitrogen, and dissolved reactive phosphorus, but significantly negatively correlated with salinity. In normal season, phytoplankton abundance was significantly negatively correlated with temperature. In dry season, it was not significantly correlated with environmental factors. Results of redundancy analysis showed that temperature, salinity, ammonium and dissolved reactive phosphorus explained the variations in phytoplankton community by 19.5%, 11.9%, 9.4% and 8.2%, respectively. These results revealed high dominance of diatoms and the main driving factors (temperature, salinity and nutrients) of phytoplankton community in Yongjiang River estuary.

[Microcosm experiments on the influence of different N/P ratios on phytoplankton community growth in the East China Sea].

In the present study, a microcosm experiment was conducted in situ for 30 days, in order to investigate the effects of different N/P ratios (1N: 1P, 4N: 1P, 8N: 1P, 16N: 1P, 32N: 1P, 64N: 1P, 128N: 1P, and 256N: 1P) on phytoplankton community growth in the East China Sea. The results indicated that the species number, cell abundance, Chl-a content, specific growth rate as well as species composition of the phytoplankton community significantly varied with the N/P ratios. After 6 days of culture, the species number, cell abundance, Chl-a content and specific growth rate in the high N/P ratio groups were significantly higher than those in the low N/P ratio groups. After 30 days of culture, the cell abundance in the groups close to the Redfield ratio (8N: 1P, 16N: 1P, and 32N: 1P) was significantly higher than those in the other treatments. On the other hand, the phytoplankton community in all the treatments was observed a definite succession from diatoms to dinoflagellates during the present study. Nonetheless, the N/P ratios strongly affected the duration of dinoflagellate bloom as well as the dominated species: at the beginning of culture (0th day-12th day), the diatoms dominated the phytoplankton community; then the relative contribution of dinoflagellates to the total cell abundance exceeded diatoms in the 4N: 1P, 16N: 1P, and 32N: 1P groups on the 18th day. After that, the relative contribution of dinoflagellates exceeded diatoms ordinally in the other groups from the 24th day to 30th day. At the end of culture, the phytoplankton community was dominated by the dinoflagellates in all the groups except for the 8N: 1P, 16N: 1P, and 32N: 1P treatments.

Biological degradation of anthroquinone and azo dyes by a novel laccase from Lentinus sp.

This study identifies a new fungal strain, Lentinus sp., that can produce extracellular forms of laccases with an activity of approximately 58 300 U/L. A purified laccase (designated lcc3) was identified by LC-ESI MS/MS as an N-linkage glycosylated protein. The isolated lcc3 cDNA is composed of 1563 bp encoding for a polypeptide of 521 amino acid residues with 4 putative Cu binding regions. Kinetic analyses revealed that the specific activity, k(cat), K(m), and k(cat)/K(m) of lcc3 at pH 2.5 and 70 °C with 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) used as a substrate was 2047 U mg(-1), 2017 s(-1), 8.4 µM, and 240 s(-1) µM(-1), respectively. Lcc3 is stable at pH 6.0-10.0 and has a midpoint temperature (T(m)) of 77.1 °C. We observed 97% decolorization efficiency on Acid Blue 80, 88% on RBBR, and 61% on Acid Red 37 by lcc3. Structural modeling analysis showed that five, four, and three hydrogen bonds can be formed between Acid Blue 80 and Arg(178), Arg(182), or Asn(358); between RBBR and His(132), Ser(134), or Asp(482); and between Acid Red 37 and Arg(178), respectively. Notably, Lentinus lcc3 efficiently reversed the toxicity of anthraquinone and azo dyes on rice seed germination and decolorized industrial textile effluent, suggesting the enzyme may be valuable for bioremediation.

[Spatial distribution patterns of heterotrophic, nitrogen, and phosphate bacteria in hypoxic zone of Yangtze River Estuary].

In August 15-28, 2009, a preliminary study was conducted on the spatial distribution characteristics of heterotrophic bacteria (HB), inorganic phosphate bacteria (IPB), organic phosphate bacteria (OPB), denitrifying bacteria (DB), and ammonifying bacteria (AB) in the hypoxic zone of Yangtze River Estuary. In the water surface, water bottom, and sediment surface of the zone, the average quantity of AB was the largest, being 307.52 x 10(4) cells x L(-1), 184.50 x 10(4) cells x L(-1), 199.97 x 10(2) cells x g(-1), followed by that of HB (87.35 x 10(4) cfu x L(-1), 86.85 x 10(4) cfu x L(-1), and 19.56 x 10(2) cfu x g(-1)), and of OPB (19.26 x 10(4) cfu x L(-1), 18.82 x 10(4) cfu x L(-1), and 19.56 x10(2) cfu x g(-1), respectively). IPB was only observed within the Yangtze Estuary, south passage of the Estuary, and Zhoushan inshore, and its average quantity in the water surface, water bottom, and sediment surface was 18.50 x 10(4) cfu x L(-1), 31.00 x 10(4) cfu x L(-1), and 7.17 x 10(2) cfu x g(-1) respectively. DB had a wide distribution, but its average quantity was low, being 3.94 x 10(4) cells x L(-1), 23.08 x 10(4) cells x L(-1), and 6.22 x 10(2) cells x g(-1) in the water surface, water bottom, and sediment surface, respectively. Salinity, NO3(-)-N, PO4(3-)-P, SiO3(2)-Si, and pH were the main factors affecting the distribution of HB, IPB, OPB, and DB in water body and sediment surface. The HB, IPB, and OPB in water bottom and sediment surface had significant positive correlation with water temperature; the HB and OPB in water bottom and the IPB in sediment surface were significantly positively correlated with dissolved oxygen (DO); while the AB in sediment surface was significantly negatively correlated with DO. Cluster analysis showed that hypoxia affected the bacterial community structure in sediment surface.

The chronic effects of oil pollution on marine phytoplankton in a subtropical bay, China.

To evaluate the effects of crude oil water accommodated fraction (WAF) on marine phytoplankton community, natural phytoplankton collected seasonally from the Yueqing bay were exposed to eight groups of crude oil WAF for 15 days under laboratory conditions. Chlorophyll a and cell density were measured, and species of phytoplankton were identified every 24 h to reflect the change of phytoplankton community. The results showed that (1) High concentrations (≥ 2.28 mg l(-1)) of oil pollution would greatly restrain phytoplankton growth (p<0.001), decrease chlorophyll a content and cell density, whereas low concentrations (≤ 1.21 mg l(-1)) did not restrain its growth but rather promoted the phytoplankton growth. (2) The biodiversity, evenness, and species number of phytoplankton were all significantly influenced by crude oil WAF in all seasons (p<0.001). (3) The dominant species changes were different under different pollutant concentrations in different seasons. Different species had different tolerances to the oil pollution, thus leading to abnormal succession.

[Seasonal distribution of macrozoobenthos and its relations to environmental factors in Oujiang River estuary sea area].

To evaluate the seasonal distribution of macrozoobenthos and its relations to environmental factors in Oujiang River estuary and adjacent waters, two cruise surveys were conducted in May 2006 (spring) and January 2007 (winter). A total of 65 species were collected, among which, polychaeta and mollusk were the dominant groups, Capitella capitata and Nassarius succinctus were the dominant species in spring and winter, respectively. The species number of macrozoobenthos was more in adjacent sea area than in estuary, and more in spring than in winter. The average biomass and density in the two seasons were 19.66 g x m(-2) and 131 ind x m(-2), respectively. There was a significant difference in the macrozoobenthos density between the two seasons, while less difference was observed in the biomass. The Shannon-Weiner index had significant difference between the two seasons, while Pielou eveness index, Margalef abundance index, and Simpsom dominance index had not. Water temperature and phytoplankton were the key factors affecting the macrozoobenthic taxa in spring, and water total organic carbon and dissolve oxygen were the key affecting factors in winter.

[Effects of residual heat and chlorine in cooling water from coastal power plant on Calanus sinicus].

According to the practical operation of coastal power plant cooling system, a simulation study was conducted on the effects of residual heat and chlorine in the cooling water on Calanus sinicus. The results showed that the thermal tolerance of C. sinicus to the cooling water was decreased with increasing exposure duration but increased with increasing acclimation temperature. When the acclimation temperature was 16 degrees C-27 degrees C, the lethal temperature of C. sinicus under thermal shock for 15, 30 and 45 min was 29.9 degrees C-31.7 degrees C, 29.4 degrees C-31.0 degrees C and 28.9 degrees C-30.3 degrees C, and that of C. sinicus continually exposed to increasing temperature for 24 and 48 h was 26.9 degrees C-28.5 degrees C and 26.4 degrees C-28.0 degrees C, respectively. When the acclimation temperature increased to a certain degree, the thermal tolerance of C. sinicus maintained at a stable level. The toxicity of residual chlorine on C. sinicus enhanced with increasing acclimation temperature, temperature increment, and exposure duration.

[Thermal tolerance of some marine copepods].

By using experimental ecological methods, the 24 hours semi-lethal temperature (24 h LT50) of typical copepods living in the coastal area of East China Sea was determined to elucidate the effects of thermal discharge from power station on the coastal ecosystem. The results indicated that different copepods at same natural acclimated temperature and specific copepod at different initial acclimated temperature had different thermal tolerance capability. The 24h LT50 of Calanus sinicus and Sinocalanus tenellus at natural acclimated temperature 13.5 degrees C was 26.9 degrees C and 25.4 degrees C, of Acartiella sinensis and Corycaeus affinis at natural acclimated temperature 14.2 degrees C was 26.7 degrees C and 30.5 degrees C, and of Centropages dorsispinatus, Paracalanus crassirostris, Acartia spinicauda and Euterpina acutifrons at natural acclimated temperature 28.0 degrees C was 34.0 degrees C, 34.3 degrees C, 35.7 degrees C and 36.0 degrees C, respectively. The 24h LT50 of S. tenellus at natural acclimated temperature 13.5 degrees C and 23.5 degrees C was 25.4 degrees C and 33.0 degrees C, respectively.

[Immunogenicity of bovine jugular vein conduits treated with different cross-linking methods].

OBJECTIVE: To evaluate the immunogenicity of bovine jugular vein conduits (BJVCs) treated with different cross-linking methods. METHODS: The BJVCs were treated with glutaradehyde (GA), dye-mediated photooxidation (DMP) and polyepoxy compound (PC) (n = 10). The tissue homogenates obtained from BJVCs treated with PC, GA, DMP, and fresh BJVCs, were mixed with the complete Freand adjavant to form the emulsive antigen, which were used to immunize rabbits correspondently. The antibody concentrations to BJVCs in those rabbits' serum were measured by counter double immuno diffusion. The immunologic responses to the BJVCs in different groups were measured with Western blotting. RESULTS: The positive bands appeared when the sera of rabbits were immunized by fresh BJVCs reacted with antigens of fresh BJVCs, but no bands appeared when the sera of rabbits were immunized by fresh BJVCs reacted with those antigens of the BJVCs treated with GA, DMP, and PC in Western blotting. CONCLUSION: The immunogenicity of BJVCs treated with PC, DMP, and GA can be reduced significantly and meet the clinical standard.