Time filter

Source Type

Kang W.,Chinese Academy of Fishery Sciences | Sun Y.,National Oceanic Consultation Center | Sun L.,Chinese Academy of Fishery Sciences | Xu Z.,Chinese Academy of Fishery Sciences | Que J.,Chinese Academy of Fishery Sciences
Chinese Journal of Applied and Environmental Biology | Year: 2013

This paper investigated from November 2010 to November 2011 the distribution of phytoplankton in the area of radiate sand ridges of north Jiangsu shoal, and analyzed the effect of topography and environmental factors on distribution of phytoplankton. Our results identified a total of 81 species of 25 genera and 3 classes, with diatoms the predominant in both species number and total phytoplankton cell abundance. The average abundance of phytoplankton were 351.74 cells/mL, 126.52 cells/mL and 240.44 cells/mL in three areas (north area in spring, north area in autumn, south area in autumn) respectively. Horizontal distribution of phytoplankton abundance showed an apparent trend of aggregation of individual dominant species, probably due to the combined action of the unique topography of sandbanks and tidal creeks and tidal current in the shoal. In autumn, Coscinodiscus subtilis was the most dominant species (0.49 of degree of dominance) in the south area, with an average abundance of phytoplankton 123.88 cells/mL. The asymmetry in abundance of horizontal distribution of phytoplankton showed a higher abundance in tidal creek terminals and sandbanks in the south and north areas, with the highest phytoplankton abundance found at the joint water of tidal creek terminals and sandbanks. Because of the different tidal wave systems, the dominant species were different at both vertical and horizontal scales. In conclusion, this study suggested that the unique topography of sandbanks and tidal creeks rather than the environmental factors play a crucial role in the formation of phytoplankton distribution patterns.

Xu Z.,CAS East China Sea Fisheries Research Institute | Sun Y.,National Oceanic Consultation Center
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2013

Based on the data from four oceanographic censuses in the Minjiang estuary and Xinghua bay during April and September 2008, this paper compared the spatial-temporal distribution of shrimp density between the two kinds of waters, involved in some impact factors such as dominant species, background of topography and geomorphy, as well as hydrological features. Results showed that total weight density (22.05kg/km2) at the Minjiang estuary was lower than that (23.33kg/km2) at the Xinghua bay, while total individual density (12.34×103 ind./km2) at the Minjiang estuary was higher than that 8.42×103 ind./km2) at the Xinghua bay during April. Same as in April, the total weight density (205.54kg/km2) at the Minjiang estuary was lower than that (329.60kg/km2) at the Xinghua bay, while total individual density (131.25×103 ind./km2) at the Minjiang estuary was higher than that 95.79×103 ind./km2) at the Xinghua bay in September. The phenomenon was related with the individual size of shrimp species from the two different waters. In the Xinghua bay, the most dominant species was a euryhaline large size species, Parapenaeopsis hardwickii, with high dominance and great contribution to total weight density, while other dominant species with low dominance and small contribution. But in the Minjiang estuary, brackish species, a very small size shrimp, Acetes chinensiswere the important dominant species with the most percent in individual densities and the greatest contribution to the total individual density. The different body size of dominant species between the two waters formed because of large size Parapenaeopsis hardwickii as the main dominant species at the Xinghua bay while small size Acetes chinensis, adapted to low salinity, as the important dominant specie at the Minjiang estuary. At the Minjiang estuary, the most shrimp resource aggregated in the south area which was thought as the main fishing ground, and, September was thought as the main fishing season because both weight density and individual density in September were far higher than those in April at the Minjiang estuary. The seasonal runoff of the Minjiang River and topography of the estuary were main environmental reasons which produced the variation in the estuary. At the Xinghua bay, spawning and feeding ground of shrimps lay in waters near the mouth of the bay in September, and the wintering ground located in the deeper outside waters of the bay in winter, related with distribution of shrimp weight density. The main dominant species Parapenaeopsis hardwickii, a warm-water species occupied 89.43% of total shrimp weight density determined the distribution pattern in April. The mixture of different water masses in waters near the mouth of the bay was another reason determined the distribution pattern. The shrimp dominant species in September showed a more diversify trend than that in April both in the Xinghua bay and the Minjiang estuary, while the dominant species at the Minjiang estuary is more diversify than that at the Xinghua bay compared with the two different kind of waters.

Xu J.,CAS East China Sea Fisheries Research Institute | Xu J.,Shanghai Ocean University | Sun Y.,National Oceanic Consultation Center | Xu Z.-L.,CAS East China Sea Fisheries Research Institute
Chinese Journal of Applied Ecology | Year: 2014

Based on data from bottom trawl surveys during spring and summer of 2010, the species composition and community structure of fish community in Lüsi fishing ground were investigated and compared with those at different latitudes. A total of 21 were identified in spring and 28 identified in summer. In spring, it was mainly composed of warm-temperate fish (9 species), accounting for 45.2% and 72.9% in the individual density and biomass density, respectively. Warm-temperate species Larimichthys polyactis, Cynoglossus joyneri and Cynoglossus semilaevis were dominant in spring. In summer, warm water species appeared in large numbers by 21, accounting for 75.2% and 71.7% in the individual density and biomass density, respectively. Collichthys lucidus and Coilia mystus were the predominant species in summer. One way-ANOVA indicated that the temperature and salinity between spring and summer in Lüsi fishing ground were significantly different, which resulted in the succession of fish community, i.e. the gradual decrease of the warm-temperate, neritic and nearshore species and the concomitant gradual increase of warm-water and estuarine Species.

Jin S.,CAS East China Sea Fisheries Research Institute | Jin S.,Shanghai Ocean University | Sun Y.,National Oceanic Consultation Center | Xu Z.,CAS East China Sea Fisheries Research Institute | And 2 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2014

The residual chlorine (RC) discharged from coastal power plant may have adverse effects on the phytoplankton in the surrounding waters, affecting the balance of the ecological system. To help us understand the inhibition mechanism of RC on phytoplankton, the RC discharged from the cooling water of a liquefied natural gas (LNG) project was simulated under laboratory conditions. The experimental subject was Chlorella sp. The experimental concentrations of RC were 0, 0.02, 0.05, 0.10 mg/L and 0.20 mg/L, based on the engineer忆s estimates of RC density in discharges. The simulation was conducted at 27益, which imitated summer temperature. The testing times were 0, 24, 48, 72 h and 96 h. Results showed that at 27°C, the RC at high concentration (0.20 mg/L) had the greatest inhibitive effect on the growth of Chlorella sp., with the strongest retarding effect (25.95%) after 48h. The inhibition effect on Chlorella sp. by the highest concentration of RC remained constant after 48h. At a low concentration (0.02 mg/L), the RC promoted the activity of Chlorella sp., which is in accordance with the hormesis mechanism. At 0.05 mg/ L and 0.10 mg/ L, the RC displayed an inhibitive effect at 24, 48 h and 72 h, and there were no marked inhibitive difference between these three time points. After 96h, there was no significant difference in the inhibitive effect of these two RC concentrations. Based on the algae growth rhythm, a growth model was fitted, finding a significant linear relationship between the control group (CG) and experimental groups (EG). The difference equation was calculated by subtracting the growth equation from the CG equation, creating the corresponding integral equation. Finally, the cumulative loss ratio (CLR) was calculated using the relative loss integral equation. At 0.05mg/l RC, CLR increased between 0 h and 72 h, with a maximum value was 8.73% at 72 h and 96 h. At 0.10 mg/l RC, the CLR was the same as at 0.05mg/L, apart from after 96h, when the 0.10mg/L CLR began to decrease. The CLR at 0.20mg/L RC was larger than the CLR of other concentrations at all time points. The CLR were 12.95%,27.07%, 41.29% and 55.59% at 24,48,72 h and 96 h, respectively. Using the RC dissipative model, the water region under investigation had an RC of 0.05mg/L. The algae theoretical loss value at 72h was calculated using the CLR and the concentration of RC at 0. 05 mg/L, and then the 0. 05mg/L maximum. Using the phytoplankton survey from the Shanghai LNG project in September 2009, cell abundance at high tide and low tide was high in coastal regions and low offshore. The average diversity index (H') of phytoplankton, mean evenness index and mean richness index were low, and the simple degree mean was high. This showed that phytoplankton distribution of individuals among species was non-uniform, the structure of the community was unstable, the ecological system was weak, and the environment might be polluted. The RC at 0.05mg/L and 0.10mg/ L was 0.047 km2 at the most, and the mean value of cell abundance was 3.67×107 cells/ m3. We conclude that phytoplankton theoretical relative loss was 1.965×1012 cells, owing to algae growth rates being inhibited by the RC density of 0.05 mg/L after 72h. © 2014 Science Press. All rights reserved.

Sun L.,CAS East China Sea Fisheries Research Institute | Ke C.,National Oceanic Consultation Center | Xu Z.,CAS East China Sea Fisheries Research Institute | Xu Z.,Xiamen University | And 3 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2013

The Zhejiang region experiences coastal upwelling characterized by low temperatures and high salinities throughout the year but particularly during the summer months. The upwelling in this area brings nutrients from the bottom to the surface, providing nutrients for large numbers of breeding plankton. The large quantities of zooplankton are a major food source for many fish and consequently the offshore waters of Zhejiang are productive fishing grounds. Another effect of the upwelling is that temperate warm water species that normally occur in deeper waters and offshore species are taken along with the current resulting in shifts in local zooplankton species composition and changes to the ecological structure and function of this group. This research was based on data from three oceanographic surveys in the offshore waters of the Yushan fishery during April, July and November of 2010. Using quantitative and qualitative methods, the primary aim of this paper was to examine the influence of upwelling on the ecological distribution of zooplankton in this area. A total of 64 species mainly dominated by copepods were identified which were classified into five major ecological groups including coastal temperate warm water species, offshore temperate warm water species, coastal subtropical water species, offshore subtropical water species and oceanic tropical water species. Coastal temperate warm water species were prevalent in spring, coastal subtropical water species and offshore subtropical water species in summer and subtropical species in autumn. The higher abundance of temperate warm water species such as Calanus sinicus, Paracalanus parvus and Sagitta nagae in summer relative to spring and autumn was primarily caused by the upwelling that transported these species from the bottom to the surface. This phenomenon is very different from the hydrodynamic processes that occur in the East and Yellow China Seas. Additionally, coastal species were the dominant zooplankton group, which means that coastal currents have the greatest influence on species composition in these waters. According to the research of Hu Dun-Xin, the main power of the Zhejiang coastal upwelling comes from the upward movement of subsurface water from the Kuroshio current as it follows the continental shelf. The subsurface water of the Kuroshio current runs southeast to northwest and shifts to the east forming an upwelling when it is blocked by the Chen Island Archipelago. With low temperatures and high salinities, the subsurface water of the Kuroshio current carries temperate warm water species and offshore species. As a result, during periods of coastal upwelling temperate warm water species are carried to the surface from the bottom, producing the unusual phenomenon were the number of temperate warm water species in summer is higher than in spring and autumn, contrary to the situation in other areas that have similar climatic conditions. In terms of abundance, coastal temperate warm water species accounted for 98.79% of the zooplankton in April and also a large proportion in July, whereas coastal subtropical water species were the dominant zooplankton group in October. Upwelling leading to the appearance of large numbers of temperate warm water species is a key factor affecting the ecological composition of zooplankton in these waters. The dominance of coastal species that are influenced by Jiao-Jiang runoff was a prime ecological characteristic of zooplankton in this region.

Discover hidden collaborations