The Qiongdongnan Basin and Zhujiang River (Pearl River) Mouth Basin, important petroliferous basins in the northern South China Sea, contain abundant oil and gas resource. In this study, on basis of discussing impact of oil-base mud on TOC content and Rock-Eval parameters of cutting shale samples, the authors did comprehensive analysis of source rock quality, thermal evolution and control effect of source rock in gas accumulation of the Qiongdongnan and the Zhujiang River Mouth Basins. The contrast analysis of TOC contents and Rock-Eval parameters before and after extraction for cutting shale samples indicates that except for a weaker impact on Rock-Eval parameter S₂, oil-base mud has certain impact on Rock-Eval S₁, Tmax and TOC contents. When concerning oil-base mud influence on source rock geochemistry parameters, the shales in the Yacheng/Enping, Lingshui/Zhuhai and Sanya/Zhuhai Formations have mainly Type II and III organic matter with better gas potential and oil potential. The thermal evolution analysis suggests that the depth interval of the oil window is between 3 000 m and 5 000 m. Source rocks in the deepwater area have generated abundant gas mainly due to the late stage of the oil window and the high-supper mature stage. Gas reservoir formation condition analysis made clear that the source rock is the primary factor and fault is a necessary condition for gas accumulation. Spatial coupling of source, fault and reservoir is essential for gas accumulation and the inside of hydrocarbon-generating sag is future potential gas exploration area.

The southern uplift of the Qiongdongnan Basin is a deepwater area in which no wells have beens drilled. The Miocene-Quaternary strata in the Xisha Islands, which are located 40–100 km to the south, are composed of carbonate reef formations. Paleotectonic and paleogeographic analyses of the basin suggest that the southern uplift experienced favorable geological conditions for the development of carbonate reefs during the Miocene. The high-impedance carbonates have high amplitudes and low frequencies on seismic profiles. The reefs are distributed on paleotectonic highs and are thicker than the contemporaneous formations. A forward model of the variation in carbonate thickness based on lithological and velocity information from wells in nearby regions can simulate the seismic response of carbonates with different thicknesses. We identified several important controlling points for determining the thickness of carbonates from seismic profiles, including the pinchout point, the λ/4 thickness point, and the λ/2 thickness point. We depict a carbonate thickness map in the deepwater area of the southern Qiongdongnan Basin based on this model. The carbonate thickness map, the paleotectonic and paleogeographic background, and the seismic response characteristics of reefs suggest that the carbonates that developed on the southern uplift of the Qiongdongnan Basin during the Miocene were mainly an isolated carbonate platform peninsula and ramp deposits. It consisted of gentle ramp platform, steep slope platform, platform depression, gravity flow, and reef bank facies.

The Liwan Sag, with an area of 4 000 km², is one of the deepwater sags in the Zhujiang River (Pearl River) Mouth Basin, northern South China Sea. Inspired by the exploration success in oil and gas resources in the deepwater sags worldwide, we conducted the thermal modeling to investigate the tectono-thermal history of the Liwan Sag, which has been widely thought to be important to understand tectonic activities as well as hydrocarbon potential of a basin. Using the multi-stage finite stretching model, the tectonic subsidence history and the thermal history have been obtained for 12 artificial wells, which were constructed on basis of one seismic profile newly acquired in the study area. Two stages of rifting during the time periods of 49–33.9 Ma and 33.9–23 Ma can be recognized from the tectonic subsidence pattern, and there are two phases of heating processes corresponding to the rifting. The reconstructed average basal paleo-heat flow values at the end of the rifting events are ~70.5 and ~94.2 mW/m² respectively. Following the heating periods, the study area has undergone a persistent thermal attenuation phase since 23 Ma and the basal heat flow cooled down to ~71.8–82.5 mW/m² at present.

BMP2 plays crucial roles in vertebrate developmental process and acts as a bone inducer during osteogenesis. We present here the molecular cloning of bmp2 cDNA from the marine flatfish Cynoglossus semilaevis, and the analysis of bmp2 expression profiling and promoter function. The full length of bmp2 cDNA sequence is 2 048 bp, which encodes a protein of 422 amino acids. Tissue expression distribution of bmp2 was examined in 14 tissues of mature individuals by quantitative real time PCR (qRT-PCR). The results revealed that bmp2 was expressed ubiquitously, and the highest expression level was detected in the spinal cord. Moreover, bmp2 expression levels were detected at 15 sampling time points of early developmental stages (egg, larva, juvenile and fingerling stages). The highest expression level of bmp2 was observed at the gastrula stage, which was about ten times higher than those at the other three embryo stages. Whole-mount in situ hybridization showed that the bmp2 signal was strongly detected at the location of the crown-like larval fin, heart and liver, and slightly expressed in the notochord at one day post hatch (dph); then the expression of bmp2 started to be concentrated in notochord at three dph. Subsequently, we characterized the 5′-flanking region of bmp2 by testing the promoter activity by Luciferase reporter assays. Positive regulatory region was detected at the location of –179 to +109. The predicted transcription factor binding sites (E-box binding factors, zinc finger transcription factor, etc.) in this region might participate in the transcriptional regulation of the bmp2 gene.

The rabbitfish Siganus canaliculatus is one of the few cultured herbivorous marine teleosts. To better understand the digestive physiology of this fish and provide data for designing formulated feed using macroalgae as an ingredient, the changes of visceral properties and digestive enzyme activities were investigated after the juveniles were fed on different types of food including raw fish (RF), formulated diet (FD) or macroalgae Enteromorpha prolifra (EP) and Gracilaria lemaneiformis (GL) for eight weeks. The results showed that the hepatosomatic and viscerosomatic indices in the RF and FD groups, as well as the relative intestine length (RIL) in the EP and GL groups, were significantly higher than those in other groups. Additionally, differences in the histological structure of the liver and anterior intestine were also observed among different dietary groups. The hepatic nuclei were displaced to the periphery by lipid inclusions in fish fed RF. The highest levels of mucosal folds were found in the anterior intestines of fish fed macroalgae. Digestive enzyme activity profiles showed obvious fluctuations in the first three weeks, and then leveled off in the following weeks. The levels of protease, lipase and α-amylase in the alimentary tract showed changes related to the levels of dietary protein, lipid and carbohydrate, respectively. Although macroalgae significantly inhibited the activity of protease in the stomach, it increased RIL and the number of mucosal folds in the anterior intestine so as to compensate for the influences on protease activities in the stomach. This study suggests that the digestive tract of rabbitfish can well adapt to different diets, and needs about three weeks to physiologically acclimatize to the nutritional status, thus implying that rabbitfish are somewhat omnivorous.

The southern Patagonian stock (SPS) of Argentinian shortfin squid, Illex argentinus, is an economically important squid fishery in the Southwest Atlantic. Environmental conditions in the region play an important role in regulating the population dynamics of the I. argentinus population. This study develops an environmentally dependent surplus production (EDSP) model to evaluate the stock abundance of I. argentines during the period of 2000 to 2010. The environmental factors (favorable spawning habitat areas with sea surface temperature of 16–18°C) were assumed to be closely associated with carrying capacity (K) in the EDSP model. Deviance Information Criterion (DIC) values suggest that the estimated EDSP model with environmental factors fits the data better than a Schaefer surplus model without environmental factors under uniform and normal scenarios. The EDSP model estimated a maximum sustainable yield (MSY) from 351 600 t to 685 100 t and a biomass from 1 322 400 t to 1 803 000 t. The fishing mortality coefficient of I. argentinus from 2000 to 2010 was smaller than the values of F_0.1 and F_MSY. Furthermore, the time series biomass plot of I. argentinus from 2000 to 2010 shows that the biomass of I. argentinus and this fishery were in a good state and not presently experiencing overfishing. This study suggests that the environmental conditions of the habitat should be considered within squid stock assessment and management.

Most fisheries in China do not have maximum sustainable yield (MSY) estimates due to limited and poor data. Therefore, finding a common method to estimate MSY or total allowable catch (TAC) for fishery management is necessary. MSYs of three important fisheries in the East China Sea were evaluated through a catch-based model. Estimates for intrinsic rate of increase (r) and five levels of process error were considered. Results showed hairtail Trichiurus japonicas (Temminck and Schlegel) and small yellow croaker Larimichthys polyactis (Bleeker) fisheries experienced overfishing from the mid-1990s to the early 2000s, and the suggested TACs were 55.8×10⁴ t and 9.06×10⁴ t, respectively. Decades of overfishing in wintering and spawning grounds of large yellow croaker Larimichthys crocea (Richardson) caused the fishery’s collapse in the 1980s, and it has not recovered until today. The Catch–MSY model generated similar estimated MSYs with other methods and may be a useful choice for the assessment of regional stocks in China.

Agarases are hydrolytic enzymes that act on the hydrolysis of agar and have a broad range of applications in food, cosmetics and pharmaceutical industries. In this study, a glycerol feeding strategy based on induction mode optimization for high cell density and β-agarase production was established, which could effectively control acetate yield. First, exponential feeding strategy of glycerol with different overall specific growth rates (μ) was applied in the pre-induction phase. The results showed that the low μ (μ=0.2) was suggested to be the optimal for cell growth and β-agarase production. Second, the effects of induction temperature and the inducer concentration on cell growth and β-agarase production were investigated in the post-induction phase. When induced by isopropyl-β-d-thiogalactoside (IPTG), the strategy of 0.8 mmol/L IPTG induction at 20°C was found to be optimal for β-agarase production. When cultivation was induced by continuous lactose feeding strategy of 1.0 g/(L·h), the β-agarase activity reached 112.5 U/mL, which represented the highest β-agarase production to date. Furthermore, the β-agarase was capable of degrading G. lemaneiformis powder directly to produce neoagarooligosaccharide, and the hydrolysates were neoagarotetraose (NA4) and neoagarohexaose (NA6). The overall research may be useful for the industrial production and application of β-agarase.

Biological CO₂ sequestration by microalgae is a promising and environmentally friendly technology applied to sequester CO₂. The characteristics of neutral lipid accumulation by two marine oil-rich microalgal strains, namely, Isochrysis galbana and Nannochloropsis sp., through CO₂ enrichment cultivation were investigated in this study. The optimum culture conditions of the two microalgal strains are 10% CO₂ and f medium. The maximum biomass productivity, total lipid content, maximum lipid productivity, carbon content, and CO₂ fixation ability of the two microalgal strains were obtained. The corresponding parameters of the two strains were as follows: ((142.42±4.58) g/(m²·d), (149.92±1.80) g/(m²·d)), ((39.95±0.77)%, (37.91±0.58)%), ((84.47±1.56) g/(m²·d), (89.90±1.98) g/(m²·d)), ((45.98±1.75)%, (46.88±2.01)%), and ((33.74±1.65) g/(m²·d), (34.08±1.32) g/(m²·d)). Results indicated that the two marine microalgal strains with high CO₂ fixation ability are potential strains for marine biodiesel development coupled with CO₂ emission reduction.

Combining a linear regression and a temperature budget formula, a multivariate regression model is proposed to parameterize and estimate sea surface temperature (SST) cooling induced by tropical cyclones (TCs). Three major dynamic and thermodynamic processes governing the TC-induced SST cooling (SSTC), vertical mixing, upwelling and heat flux, are parameterized empirically using a combination of multiple atmospheric and oceanic variables: sea surface height (SSH), wind speed, wind curl, TC translation speed and surface net heat flux. The regression model fits reasonably well with 10-year statistical observations/reanalysis data obtained from 100 selected TCs in the northwestern Pacific during 2001–2010, with an averaged fitting error of 0.07 and a mean absolute error of 0.72°C between diagnostic and observed SST cooling. The results reveal that the vertical mixing is overall the pre dominant process producing ocean SST cooling, accounting for 55% of the total cooling. The upwelling accounts for 18% of the total cooling and its maximum occurs near the TC center, associated with TC-induced Ekman pumping. The surface heat flux accounts for 26% of the total cooling, and its contribution increases towards the tropics and the continental shelf. The ocean thermal structures, represented by the SSH in the regression model, plays an important role in modulating the SST cooling pattern. The concept of the regression model can be applicable in TC weather prediction models to improve SST parameterization schemes.