Dynamics of picoplankton in the Nansha Islands area of the South China Sea

Dynamics of major picoplankton groups, Synechococcus (Syn), Prochlorococcus (Pro), picoeukaryotes (Euk) and heterotrophic bacteria (Bact) was investigated by flow cytometry for the first time in the Nansha Islands area in the South China Sea. Averaged over the whole investigation area, depth-weighted integrated cell abundance (DWA) of Syn, Pro, Euk and Bact was 1.6 (0.4-5.7)×103, 5.4 (0.1-7.3)×104, 0.7 (0.2-2.2)×103, and 2.3 (1.4-3.2)×105 cells/mL respectively. Picoautotrophic cell abundance was low in the northwest part of the Nansha Islands where surface water temperature was low and the upper mixed layer was shallow. Concurrently, a surface maximum vertical distribution pattern was observed in this area. While in the southeast and east zones where temperatures were relatively higher and nitraclines were deeper, picoplankton is abundant and a subsurface maximum around 50-75 m is observed. Coupling of horizontal and vertical distribution patterns of picoplankton abundance and hydrological status was found, suggesting a strong influence of currents and water column structure on picoplankton distribution in the investigation area. Contrary to that in the shelf water in the East China Sea, the relationship between Pro and Bact in the Nansha Islands area in the South China Sea was not significantly negative but weakly positive. Moreover, a similar distribution pattern of Syn and Pro was observed. Possible reasons for these differences in the two marine regimes were discussed.

Circulations east of Taiwan and in East China Sea and east of Ryukyu Islands during early summer 1985

A modified inverse method is used to compute the circulations east of Taiwan and in the East China Sec and east of the Ryukyu Islands with hydrographic data obtained during early summer of 1985. The computational region covers an area west of 129°E and from 21°45'N to 35°N. The computed results show that: (1 ) The net volume transport (VT ) of the Kuroshio through 21°45'N Section east of Ta Taiwan and west of 123°E is about 45 × 10￣6 m￣3/sduring early summer of 1985. The Kuroshio has. two current cores. One is located near Taiwan, and its velocity isvery large and its maximum velocity is 226 cm/s at the 100 m level, which is close to the maximum velocity of the beginning of the Kuroshio east of the Philippines. The other is located further to the east, and its maximum velocity is159 cm/s at the 100m level; (2) through a transect northwest Of Miyakojima Island and a transect southwest of Okinawa laaed the volume transports of the Kuroshio in the East China Sea both are about 25 × 10￣6 m￣3/s. The maximumvelocity of the Kuroshio at these two sections is 194 and 128 cm/s, respectively, and both are located on the shelfbreak; (3) beneath and east of the Kurohio there are the countercurrent (4) southeast of Okinawa Island there is anortheastward current, and its VT at Section HI is about 12. 6 × 10￣6 m￣3/s, and it comes from a westward flow at 129° This project was supported by the National Natural Science Foundation of China under contract No. 49476278.(Second Institute of Oceanography, State Oceanic Administration, Hongzhou310012, China) (Institute of Oceanography, Taiwan University, Taipei, China)E Section and the recirculating gyre, and does not originate from the Kuroshio east of Taiwan during early summer of 1985. There is a southwestward abyssal current east of Okinawa Islands (5) there are several different scale eddies in this computational region. For example, there is a meso-scale strong cyclonic eddy east of Miyakojima Island.

Consistent CMT solutions from Harvard University before great earthquakes in Kurile Islands and its significance for earthquake prediction

In the paper, we use the Central Moment Tensor (CMT) solution acquired by Harvard Univ. for the earthquakes occurred in Kurile Islands to analyze the consistent focal mechanism in the area and propose the idea of making earthquake prediction based on the consistent parameter a of focal mechanism and stress field. The results from the study indicate that before Mw greater than or equal 7.5 earthquakes, the consistent parameter a decreases, which starts about 10-110 days and ends about 30-2 days before the great earthquakes. Although the phenomenon is not totally the same for individual earthquake, the difference is not large. Certainly, the phenomenon should be tested by time for its reliability. However, it should not be random that the focal mechanism of Mw greater than or equal 5.3 earthquakes are consistent successively with the stress field in an area of several hundreds kilometers in length. It should be a phenomenon of predictive significance. When the accumulated earthquake examples are sufficient, uniform judgment criteria and prediction principles can be stipulated then.

Growing correlation length of moderate-sized earthquakes prior to two great earthquakes near Sumatra Island

Seismic correlation length for moderate earthquakes prior to two great earthquakes in the northern sea area of Sumatra Island （Mw9.1 in 2004 and MsS. 6 in 2012） has been studied, using method of Single- Link-Cluster （ SLC ） analysis, and found to show a power-law growth about two years before their occurrences. No such growth was found for a magnitude 7 earthquake in the same area. This result suggests the occurrence of a physical process of critical-point characteristics in the source area before the great earthquakes.

Distribution of Organic Matter,Iron,Mangenese in Surface Sediments in the Nansha Islands Sea Area,South China Sea

Concentrations of organic matter, iron and manganese in the deep sea surface sediments in the Nansha Islands sea area, South China Sea are measured. Horizontal and vertical distributions of iron and manganese are discussed. The vertical distribution of iron and manganese in the sediments results from reduction, diffusion, and redeposition of manganese (or iron) oxide and hydroxide in the sediment. There are the maxima of iron and manganese in solid phase in the top of the sediment, which is caused by the penetration of O2 and the upward flux of Mn2+ ( or Fe2+ ). Manganese bacteria play a very important role in the cycle of solid-phase iron and manganese in the ocean environment. Manganese bacteria oxidize Mn2+ ( or Fe2+ ) in dissolved state to Mn4+ ( or Fe3+ ) in oxidized state under the aerobic condition, whereas they reduce iron and manganese in anaerobic conditions.

Distribution of Dissolved Inorganic Phosphate in Nansha Islands Sea Area, Southern South China Sea

Based on the survey data from the program Multidisciplinary Expedition to Nansha Islands Sea Area, the distribution of dissolved inorganic phosphate ( PO43--P ) in the sea water of Nansha Islands Sea Area is comprehensively analyzed in this paper. The results show that PO43--P concentration in the sea water of southeastern Nansha Islands Sea Area is commonly higher than that in the other sea areas; the vertical distribution of PO43--P concentration varies inconspicuously in different seasons; the concentration of PO43--P increases with water depth and changes most greatly in the layer of 50 ～ 100 m. The diurnal variation of PO43--P concentration differs in different seasons and at different observation stations. The distribution and variation of PO43--P concentration result from the physical and biological processes together.

Study of Radiolaria in the surface sediments from the area east of Taiwan Island

The species and characteristics of Radiolaria in the surface sediments were systematcally investigated in the sea east of Taiwan Island. One hundred and seventy-eight species of Radiolaria (including 21 unidentified species) have been identified in the surface sediments, and they belong to 2 orders, 34 families and 101 genera. Among them there are 19 families, 70 genera, 134 species of Spumellaria and 15 families, 31 genera, 44 species of Nassellaria. Of the 178 species of Radiolaria, the individual number of Spumellaria amounts to 88.1 % of the total individual number, and that of Nassellaria amounts to 11.9% of the total individual number. It is shown that most of the dominant species belong to the tropical and subtropical dominant species and are brought into the area mainly by the Kuroshio, and some affecting factors including the submarine topography, submarine sediments, upwelling current east of Taiwan Island and carbonate dissolution play a secondary role in forming the Radiolaria distributions.

Differential expression analysis of coronary heart disease related genes in Hainan residents

Objective:To explore the correlation between coronary heart disease related genes and coronary heart disease in hospitalized patients in Hainan,and to provide theoretical basis for enriching the screening methods of high-risk groups of coronary heart disease in Hainan,and optimizing the prevention and treatment strategies.Methods:We select hospitalized patients born in Hainan and aged>30 years old from the Second Affiliated Hospital of Hainan Medical Unversity between January 1,2020 and June 30,2022,and divided the patients into the coronary heart disease group and the non-coronary heart disease group.PCR real-time fluorescence was used to measure gene expression,and Spearman correlation analysis was used to explore the correlation between gene expression and coronary heart disease.Results:A total of 55 whole blood samples were collected from non-coronary heart disease patients(including 26 women and 29 men),with a median age of 57 years,and 170 whole blood samples from coronary heart disease patients(including 44 women and 126 men),with a median age of 63.17.Apolipoprotein B gene(ApoB)was highly expressed in patients with coronary heart disease(P<0.001);AGT gene(P=0.0158),ApoE gene(P=0.0126),FGB gene(P=0.005),GNB gene(P=0.0151),MTFHR gene(P=0.0119),SEL gene(P=0.005),TNF gene(P=0.0298)were significantly overexpressed in the non-coronary heart disease group.The expression of NOS3 gene(P=0.3047),IL6 gene(P=0.7239),ACE gene(P=0.7852)was not different between the two groups.Coronary heart disease was negatively correlated with AGT gene(r=-0.163,P=0.011,P<0.05),positively correlated with APOB gene(r=0.75,P=0,P<0.01),negatively correlated with FGB gene(r=-0.163,P=0.011,P<0.05),negatively correlated with GNB gene(r=-0.165,P=0.011,P<0.05),negatively correlated withSEL gene(r=-0.171,P=0.007,P<0.01),negatively correlated with MHTHR gene(r=-0.210,P=0.001,P<0.01)and negatively correlated with TNF gene(r=-0.131,P=0.04,P<0.05),but coronary heart disease was not correlated with APOE,NOS3,ACE,IL6 and other genes(P>0.05).The ApoB gene of coronary heart disease was negatively correlated with triglyceride(r=-0.461,P=0),positively correlated with age(r=0.173,P=0.009),positively correlated with total cholesterol(r=0.499,P=0),negatively correlated with high-density lipoprotein(r=-0.181,P=0.007),and negatively correlated with low-density lipoprotein(r=-0.143,P=0.031).Conclusion:(1)The detection of apolipoprotein B gene expression may be used as an indicator for screening coronary heart disease in the coronary population in Hainan.It may increase the risk of coronary heart disease by affecting the level of total cholesterol.A larger sample of research is still needed.(2)AGT,ApoE,FGB,GNB,MTFHR,SELE,TNF and other genes may be the protective genes of non-coronary heart disease population in Hainan,and the high expression of these genes may reduce the occurrence of coronary heart disease,which still needs further study.

Study on the Urban Heat Island Effects and Its Relationship with Surface Biophysical Characteristics Using MODIS Imageries

This study assesses surface urban heat island (UHI) and its associated surface physical characteristics using remote sensing approaches. TERRA/MODIS images acquired in 2005 in three different seasons were selected to generate land surface tem-perature and surface characteristics for the Changsha-Zhuzhou-Xiangtan metropolitan area in China. The intensity of urban heat is-land effects and its seasonal variations were examined. The result showed that UHI effects were significant both in the summer and the spring. Land surface temperatures in the city were 8 ℃ to 10℃ warmer than those in surrounding rural areas in the spring and the summer seasons. Although UHI effects exist in winter, they are not significant. Land surface temperature in the city was 4℃ warmer than that in surrounding rural areas in winter. This study uses normalized difference vegetation index (NDVI) and normal-ized difference built-up index (NDBI) as indicators of surface physical characteristics and investigates the relationship among land surface temperature (LST), NDVI and NDBI. The results from this study indicate that, while the relationship between LST and NDVI changes in different seasons, there is a strong positive linear relationship between NDBI and LST for all seasons. The amount of slope and intercept of the linear relationship between NDBI and LST can indicate the magnitude of UHI for different seasons. This finding suggests that NDBI provides an alternative physical indicator for analyzing LST quantitatively over different seasons, and therefore providing a useful way to study UHI effects using remote sensing.