Zhou Chengxu

Prevention of fish oil rancidity by phlorotannins fromSargassum kjellmanianum

Known only in the Phaeophyceae, phlorotannins (brown algal polyphenols) are a class of natural products with potential uses in pharmacology. This study reports that phlorotannins fromSargassum kjellmanianum can prevent fish oil from rancidification; the antioxidation activity was about 2.6 times higher than that of 0.02% BHT (tertbuty-l4-hydroxytoluene).

Studies on extraction procedure and antioxidative activity of phlorotannins fromSargassum kjellmanianum

Known only in phaeophyceae, phlorotannins (brown algal polyphenols) are natural products with potential uses in pharmacology. This study yielded an extraction procedure to obtain high purity, high molecular weight phlorotannins fromSargassum kjellmanianum and revealed the characteristics of their infrared and flourescence spectra. The antioxidative activity of phlorotannins, which was about 2.6 times as strong as that of 0.02% BHT (tert-butyl-4-hydroxytoluene), showed potential for preventing oil rancidification.

Phytoplankton distribution and community structure in the East China Sea (ECS) continental shelf

This paper deals with the distribution and community structure of phytoplankton revealed by data obtained in a cruise in April and one in Oct.–Nov., 1994. Among 140 species of phytoplankton (including varieties and formas) identified, 104 species belonged to Bacillariophyta and 32 species belonged to Pyrrhophyta. In April, the biomass of phytoplankton was 0.09×104–465×106 cells/m3, and the dense area was located in the Zhejiang coastal zone and the estuary of the Changjiang River; the density of the studied areas west part was always higher than that of the east part. In October and November, the phytoplankton biomass was 0.42×104–289.9×104 cells/m3, and the dense area was located in the upwelling zone near the Zhejiang coast. In spring and autumn, biomass was very low in the outer part of the East China Sea continental shelf area, where phytoplankton was classifiable into two communities based on the phytoplanktons ecological characteristics and environmental parameters such as water temperature and salinity, i.e. neritic community environment characterized by warm temperature and low salinity and pelagic community environment characterized by high temperature and high salinity.

Verticla profiles of chl-a and primary productivity in the middle continental shelf area and eddy area of the East China Sea

Vertical profiles of chl-a and primary productivity in the middle continental shelf area and eddy area of the East China Sea were studied using data from a cruise in the East China Sea in February to March, 1997 and a cruise in July, 1998. The results showed that chl-a vertical distribution closely related to in situ hydrological and nutrient conditions. Chla-a concentration ranged from 0.22 to 0.35 mg/m3 and 0.93–1.09 mg/m3 in the eddy area and in the middle continental shelf area, respectively. In both areas, chl-a concentrations in deep layers were slightly higher than those in shallow layers, but was of the same order of magnitude. In summer, when a thermocline existed in the water column, highest chl-a concentrations appeared at the base of the thermocline layers in both areas. In the eddy area, chl-a concentration maximized at 31.743 mg/m3, and averaged 1.143 mg/m3 below 30 m depth. In the middle continental shelf area, the highest chl-a concentration was 2.120 mg/m3, the average was 1.168 mg/m3. The primary productivity reached 1418.76 mgC/(m2·d) in summer and 1360.69 mgC/(m2·d) in winter. In the eddy area, the primary productivity was 787.50 mgC/(m2·d) in summer and 159.04 mgC/(m2·d) in winter. Vertical carbon sinking rate from the deep layer to the bottom in both areas is also discussed in this paper.

New observations on the meiotic process in the marine dinoflagellateNoctiluca scintillans (Noctilucales, dinophyceae)

The meiotic process inNoctiluca scintillans were observed under light microscope. Some abnormal cell divisions, incompletely separated “zoospores” and the changes of the zoospores are described in this paper. Together with the findings of field samplings and the previous results by other researcher, the process of meiosis inN. scintillans was supposed to be a pathway to reduce the extra high density of NH3−N within the cell in order to ensure normal population growth.