Effects of shellfish culture on the community and mortality of zooplankton in a subtropical Bay

Spatial and temporal distribution of abundance,community structure and succession,and mortality of zooplankton were examined in a subtropical bay—the Qinzhou Bay,Guangxi,South China,to evaluate the impact of oyster culture on zooplankton.Data on zooplankton abundance,phytoplankton biomass,and environmental parameters were collected in 12 routine samplings at four sites in the Qinzhou Bay in 2018.Results show that the hydrological environment in the estuary affected the temporal variation of zooplankton of the Qinzhou Bay.However,the oyster culture affected the spatial distributions of zooplankton.The abundance of zooplankton outside the oyster farm was higher than that inside,whereas the mortality outside the oyster farm,on the contrary,was lower than that inside.Oyster culture in the Qinzhou Bay had built a significant impact on the abundance and community composition of zooplankton,and the food shortage caused by the ingestion of oyster might exacerbate the mortality of zooplankton in the Qinzhou Bay.In addition,the large-scale oyster culture increased the spatial heterogeneity of the community structure of zooplankton inside and outside the oyster farms.Findings of this study provide a reference for future policy-making in aquaculture management.

Catch organism assemblages along artificial reefs area and adjacent waters in Haizhou Bay

To better understand the community patterns mediated by connectivity in artificial reefs of coastal areas, it is necessary to understand the distribution and coexistence of organisms with artificial reefs area and adjacent waters. This study was conducted to examine main catches assemblages collected by trawls in Haizhou Bay,which included five habitats: the artificial reef area(AR), aquaculture area(AA), natural area(NA), estuary area(EA) and comprehensive effect area(CEA). The result shows that the total abundances of species in the five habitats were highly different(univariate PERMANOVA: P = 0.001, n = 24), but some species were also unique in their habitat(e.g. Scapharca subcrenata and Glossaulax didyma in AA). The body size distribution of specific species between habitats are different. For Collichthys lucidus, their body size in AR(14.63 cm ± 1.64 cm) and EA(14.3 cm ± 0.85 cm) is higher than that in NA(10.65 cm ± 1.64 cm), CEA(11.28 cm ± 1.85 cm) and AA(12.1 cm ±0.43 cm), which indicates the potential connection from AR to EA mediated by their adult population. We concluded that artificial reefs in AR can be considered key components that have the ability to support species assemblages in adjacent habitats. This study has implications for the conservation and monitoring of species assemblages in coastal areas in terms of that artificial reefs can be applied in different stages of habitat protection implementation and in different combinations of scenarios.

From Chooz to the Ling'ao NPP:The Technology Transfer of Pressurized Water Reactor Technology from France to China

The transfer of pressurized water reactor(PWR)technology from France to China is an important event in the history of Sino-French scientific and technological relations.China has gradually achieved self-reliance in the field of PWR technology through the introduction and subsequent absorption of France's 900 MW reactors.Compared with the process of introducing and absorbing similar technology from the United States by France,China's experience has been more complicated.This circumstance reflects the differences in the nuclear power technology systems between the two countries.France's industrial strength and early acquisition of nuclear power technology laid a solid foundation for mastering PWR technology.On the other hand,although China established a weak foundation through the implementation of the"728 Project,"and tried hard to negotiate with France,the substantive content of the technology transfer was very limited.By way of the policy transition from"unhooking of technology and trade"to"integration of technology and trade,"China ultimately accomplished the absorption and innovation of PWR technology through the Ling'ao NPP.

Evaluation of the Spatial Quality of the Greenway on the Tonghui River in Beijing

This study organized the current status of tangible cultural heritage along the Tonghui River.The spaces along the Tonghui River were classified according to the farmland,suburban areas,urban residential areas,and urban center areas.Spatial analysis of the current situation was conducted through Baidu Street View images,with a focus on evaluating the spatial environment around the tangible cultural heritage.Negative factors affecting the reuse of cultural heritage were analyzed,such as poor appearance of buildings and low accessibility of transportation along the Tonghui River.

Water,organic matter,nitrogen and phosphorus contents in sediment of a large-scale mariculture area in the Zhelin Bay of eastern Guangdong Province,China

The Zhelin Bay is one of the most important bays for large-scale mariculture in Guangdong Province, China. Owing to the increasing human population and the expanding mariculture in the last two decades, the ecological environment has greatly changed with frequent harmful algal blooms. A monthly survey of water content, organic matter （TOM）, and various forms of nitrogen and phosphorous in sediment from July 2002 to July 2003 in the bay was conducted. The results showed that the water content was correlated significantly with TOM and various forms of nitrogen and phosphorus and can be used as proxy for quick and rough estimate of these factors in the future surveys. TOM was also correlated significantly with various forms of nitrogen and phosphorus, indicating that it was one of the key factors affecting the concentrations and distributions of nitrogen and phosphorus in the investigated waters. Average total Kjeldhal nitrogen （TkN） content was（ 1 113.1 ± 382.5）μg/g and average total phosphorus （TP） content was（567.2± 223.3）μg/g, and both were much higher than those of similar estuaries in China and elsewhere. Average nitrogen and phosphorus tended to be higher inside than outside the bay, higher at aquaculture than non-aquaculture areas, and higher at fish-cage culture than oyster culture areas, suggesting that large-scale mariculture inside the bay played an important role in the eutrophication of the Zhelin Bay. Various forms of nitrogen and phosphorus concentrations were higher during the warm season （July--September）, which was due to the increased decomposition and concentration of organic matter resulted from the fast growth and high mortality of the cultured species. Compared with July 2002, TkN and TP contents were much higher in July 2003, in consonance with the eutrophication of the Zhelin Bay. Because exchangeable phosphorus （Ex-P）, iron-bounded phos- phorus （Fe-P） and organic phosphorus （OP） combined accounted for 34.3% of the TP and authigenic phosphorus （Au-P） accounted for 49.2% of the TP, biological phosphorus （BP） that includes Ex-P, Fe-P, OP, and a portion of Au-P, thus accounted for 34.3% to 83.5% of the TP in the Zhelin Bay, which was within the percentage range, but with a high absolute value among the estuaries. Au-P was the most important species of phosphorus and accounted for 49.2% of the TP during the investigation. Since eutrophication in the water column can lead to reduction of pH in sediment and release of phosphorus in Au-P combined with authigenic spodiosite and calcium carbonate, high content of Au-P in the sediment maybe act as a time bomb that can trigger a vicious cycle of eutrophication and large-scale harmful algal bloom in the Zhelin Bay.

Upper layer waters and their northward extension from Prydz Bay in summer

In this paper, CTD observational data obtained during the 15th Chinese National Antarctic Research Expedition (CHINARE-15) in the Southern Ocean are used to analyse and study water mass distribution in the Prydz Bay and its adjacent seas. The area, depth, and the thermohaline characteristics are identified for the Prydz Bay summer coastal surface water, the Prydz Bay winter water, the Prydz Bay shelf water, and the circumpolar deep water. Based on the above discussion, the northward extention of the Prydz Bay shelf water are found. Then the thermodynamic and the dynamic characteristics are further discussed, dealing with the inversion layer depth of the water temperature, the locations of the minima of the vertical temperature distribution and the temperature vertical gradient in the water column, the baraclinicity, and the effect of Coriolis deflection force.

Research on Hydraulic Block Scenarios in the Land Conservation Zone of the Headwaters Area of Jinshu Bay

[Objective] The aim was to study the hydraulic block scenarios in the water source land conservation zone in Jinshu Bay so as to ensure the water quality in the water sources in Jinshu Bay.[Method] By dint of one dimension water amount and water quality mode in the river net in Taihu,the water flow movement characteristics and pollutants transportation rules in the water sources areas in Jinshu Bay under five kinds of hydraulic block scenarios were compared and discussed.[Result] After demolishing the temporary soil dam in the water source conservation zone in Jinshu Bay,water amount and pollutants increased and water quality deteriorated.It was necessary to take certain hydraulic power to block and control the pollutants in the preservation area;after demolishing the dam,there was less water amount and pollutants.The water quality improved significantly.The hydraulic block facility in the preservation area and its surroundings were all releasing and not introducing;the one along the mouth of the river of Mentianji Gang,Jinshugang and Longtanggang were introducing and not releasing,which only restricted poor-quality water in Beijing-Hangzhou Canal and Huguang Canal flowing into the conservation zone.The water into the conservation zone was all from Gonghu.The water mobility within the conservation zone was good.The regional water quality improved to the largest scale.[Conclusion] Judging from the water flow movement characteristics and pollutants transportation rules in Jinshu Bay,the fifth proposal was more appropriate.

Succession and seasonal variation in epilithic biofilms on artificial reefs in culture waters of the sea cucumber Apostichopus japonicus

Periphytic biofilms in aquaculture waters are thought to improve water quality, provide an additional food source, and improve the survival and growth of some reared animals. In the AsiaPacific region, particularly in China, artificial reefs are commonly used in the commercial farming of sea cucumbers. However, few studies have examined the epilithic biofilms on the artificial reefs. To gain a better understanding of the succession of epilithic biofilms and their ecological processes in sea cucumber culture waters, two experiments were conducted in culture waters of the sea cucumber Apostichopus japonicus in Rongcheng, China, using artificial test panels. On the test panels of succession experiment, more than 67 species were identified in the biofilms. On the test panels of seasonal variation experiment, more than 46 species were recorded in the biofilms. In both experiments, communities of epilithic biofilms were dominated by diatoms, green algae and the annelid Spirorbis sp. In the initial colonization, the dominant diatoms were Cocconeis sp., Amphora spp. and Nitzschia closterium in June, which were succeeded by species of Navicula, Cocconeis and Nitzschia(July to September), and then by Licmophora abbreviata, Nitzschia closterium and Synedra spp. in the following months. A diatom bloom in the autumn and filamentous green algae burst in the summer were also observed. Ecological indices well annotated the succession and seasonal changes in epilithic communities. Multidimensional scaling(MDS) analysis found significant differences in diatom community composition among months and seasons. Fast growth of biofilms was observed in the summer and autumn, whereas the biomass of summer biofilms was largely made up of filamentous green algae. Present results show that the components of epilithic biofilms are mostly optimal foods of A. japonicus, suggesting that biofilms on artificial reefs may contribute important nutritional sources for sea cucumbers during their growth seasons. Future works should include quantitative determination of the contribution of epilithic biofilms to the diet of A. japonicus, potential roles of epilithic biofilms in regulating the water quality of sea cucumber ponds, and the regulation of epilithic biofilms in sea cucumber culture ponds.

Changes of Water Temperature and Harmful Algal Bloom in the Daya Bay in the Northern South China Sea

Economic development around the Daya Bay, China has profoundly affected the marine environment in the bay area in recent years, particularly since the operation of Daya Bay Nuclear Power Station （DNPS） in 1994. This study analyzed the changes of water temperature and harmful algal blooms （HABs） for two periods： 1983-1993 and 1994-2004, using in situ and satellite data. Results showed that yearly mean surface water temperature （SWT） and Chl-a concentration （Chl-a） increased by 1.1 ℃ and 1.9 mg/m^3, respectively, after 1994. The monthly occurrence of HAB was found to have increased also. HABs appeared only in spring and autumn before 1994, but occurred all the year round after 1994. SWT, Chl-a and HABs all increased significantly in May. Those changes were associated with environmental changes in this area, such as thermal discharge from the DNPS and enhancement of eutrophication from human activities around the Daya Bay.

Phytoplankton ecology in the adjacent waters of the Daya Bay Nuclear Power Station in Guangdong in spring

The purpose of this study is to detail the ecological characteristics of phytoplankton in waters around the Daya Bay Nuclear Power Station in Guangdong (GNPS) (Fig. 1) in spring, the bloom period of algae. The collections with a small temporal scale of every three days were made during 30 cruises from March to May in 1987. Such an investigation has never been carried out before in China except that the seasonal distribution and composition of phytoplankton in these regions were reported in

Ecological characteristics of the abundance and distribution of bacteria in the waters nearby the front of the Hangzhou Bay

Abundance of total bacteria, heterotrophic bacteria, coliform and oil degradable bacteria and their relations with salinity and suspended matter in the frontal waters in the Hangzhou Bay are described. The results obtained show that the highest abundances of total bacteria , heterotrophic bacteria are encountered around the front and near the northern shore of the Hangzhou Bay, where a positive correlation ( r =0. 70) between the total bacteria abundance and the total suspended matter (TSM) is persent. Moreover,the abundance of oil degradable bacteria being an indicator of oil pollution, is also high in that region.

Distribution of modified Circumpolar Deep Water and its threat in Vincennes Bay,East Antarctica

The Antarctic Bottom Water formation site Vincennes Bay,East Antarctica is experiencing a substantial intrusion of modified Circumpolar Deep Water(mCDW),which may inhibit the formation of Dense Shelf Water(DSW)and drive basal melting of the ice shelves.Based on hydrographic data obtained from March to November in 2012,we evaluated the spatial spread of mCDW over the continental shelf region of Vincennes Bay and the associated temporal evolution of water properties,as well as the sea ice formation effect on water column in the coastal polynya.Results show that two branches of mCDW occupied the deep layers of the continental shelf,distinguished by the potential density(smaller than 27.8 kg/m^(3) or not)when potential temperatureθ=0.5°C in theθ-salinity space.The warmer and less dense branch observed on the east plateau,accessed the eastern ice shelves in the coastal polynya to drive basal melting of ice shelves.In contrast,the other colder and denser branch in the mid-depression reached the western Underwood Ice Shelf.DSW formation was detectable in the coastal polynya during September-November,proving the occurrence of deep convection.Surface heat loss and brine rejection during the intensive sea ice formation contributed to the destratification of the water column in the coastal polynya.It was estimated that at least 1.11±0.79 TW heat carried by mCDW into the inner part of the polynya.

Construction of Cultural Landscapes in Changjiang Waters of Jingdezhen since the Song Dynasty

Waters of Changjiang River were first defined.As the mother river of Jingdezhen,Changjiang River once was the only way for this ancient ceramic city communicating with the outer world,and played an important role in the economic development and ceramic industry of Jingdezhen.By consulting documents and investigating the local area,this study expounded and proved kiln landscapes of this ceramic city along the Changjiang River,traffic landscapes in the Changjiang River,folk customs and architectural landscapes,as well as unique images.The construction and evolution of its cultural landscapes were analyzed to explore the development history of this city.Characteristic cultural landscapes with the Changjiang River as the principal line were highlighted,"water elements" in the urban development of Jingdezhen,production and transportation of ceramic industry were demonstrated,so as to provide useful references for the reformation project of "one river and both banks",and the construction of new cultural landscapes in Jingdezhen,help Jingdezhen go smoothly in its urban development and transition from a traditional to a modern city.

Spatiotemporal characteristics of summer hypoxia in Mirs Bay and adjacent coastal waters,South China

Mirs Bay is a semi-enclosed bay neighboring the Zhujiang(Pearl)River estuary,one of the largest estuarine systems in the world.The long-term historical observational data(1994-2017)of temperature,salinity,dissolved oxygen(DO),and biochemical parameters were used to examine the spatiotemporal distribution of hypoxia in Mirs Bay and adjacent coastal waters.Results show that bottom hypoxia varied seasonally and interannually.Hypoxia mainly occurred from June to September in Mirs Bay and the transition zone in the southern waters of Hong Kong,and the recorded hypoxia events have increased from 2007.The density difference between the bottom and surface layers was positively related to the bottom apparent oxygen utilization(AOU)(R=0.620,P<0.001)and negatively related to the bottom DO(R=0.616,P<0.001),indicating that water column stratification was an essential prerequisite for the formation of bottom hypoxia in summer.The bottom oxygen consumption and hypoxia had higher positive correlation with the seasonal thermocline(R=0.683,P<0.001)than the halocline(R=0.540,P<0.001),including in the area was affected by freshwater plume.The insignificant relationship between AOU and nutrients indicated that local eutrophication was not the only important factor in the formation of the hypoxic zone during summer.The decrease in phosphorous owing to the pollutant reduction policy and the increase in nitrate may have led to an increase in hypoxia events in the bay where waters therein are characterized by nitrogen-limitation.The increase in chemical oxygen demand in wastewater also promoted oxygen consumption.Compared to the adjacent coastal waters influenced by Zhujiang River plume water,the Mirs Bay experienced more hypoxia events.The high concentrations of ammonium and total Kjeldahl nitrogen in the sediment of Mirs Bay increased the oxygen depletion in the bottom water.The long residence time of the near-bottom water in Mirs Bay increased the risk of bottom hypoxia events,although the nutrient concentrations were lower than those in the transition zone.These factors lead to differences in hypoxia occurrence in Mirs Bay and adjacent coastal waters.

Discussion on Cultural Inheritance of Water Parks in the Yellow River Basin

At the Symposium on Ecological Protection and High-quality Development of the Yellow River Basin, General Secretary Xi Jinping pointed out that "it should deeply explore the time value contained in the Yellow River culture, tell the story of the Yellow River well, and protect, inherit and carry forward the Yellow River culture". Water park is an important carrier of the Yellow River culture transmission. In this paper, the basic characteristics and regional distribution of water parks in the Yellow River basin are analyzed. For the problems faced by cultural heritage of water parks in the Yellow River basin, from three aspects of exploring and integrating the connotation, innovating communication methods, and shaping brand IP, cultural heritage of water parks in the Yellow River basin is discussed. It is beneficial to carry forward the Yellow River culture, and better meet the spiritual and cultural needs of the people.

The effects of spring-neap tide on the phytoplankton community development in the Jiaozhou Bay, China

The development of the phytoplankton community was studied in the Jiaozhou Bay during the spring to neap tide in August2001, through three cruises and a 15 d continuous observation. This investigation indicates that diatom cell abundance increasedsharply following the end of a spring tide, from 9 cells/cm3 to a peak of 94 cells/cm3. The dominant species composition andabundance show a quick species sequence from spring to neap tide, and the dominant species at the start phase is Skeletomenacostatum, then changes to Chaetoceros curvisetus, finally it changes to Eucampia zodiacus. Silicate concentration increasesduring spring tide, as a result of nutrient replenishment from the watersediment interface, its initial average concentration inneap tide is 1.39 mmol/dm3 and reached the peak average concentration of 8.40 mmol/dm3 in spring tide. But the nitrogenconcentration dropped due to dilution by the low nitrogen seawater from the Huanghai Sea, its initial average concentration inneap tide is 67 mmol/dm3 and decreased to the average concentration of 54 mmol/dm3 in spring tide. The degree of siliconlimitation was decreased and phytoplankton, especially diatoms, responds immediately after nutrient replenishment in thewater column. Skeletonmea costatum, as one of the dominant species in the Jiaozhou Bay, shows a quicker response tonutrient availability than Eucampia zodiacus and Chaetoceros curvisetus. It is proposed that dominant species compositionand water column stability synchronously determine the development of phytoplankton summer blooms in the Jiaozhou bay.

Features of physical oceanography in the oceans near the Prydz Bay during the 1998/1999 austral summer

Thermohaline features, spatial extensions, and depths of the antarctic circumpolar deep water, the antarctic bottom water, and the upper layer water near the Prydz Bay （ including the Prydz Bay s.mmer surface water, the antarctic winter water, and the Prydz Bay shelf water ） are analyzed and studied by use of the full depth CTD data obtained in the Southern Ocean near the Prydz Bay during the 1998/1999 austral summer. The northward extension of the shelf water, the thickness of the temperature inversion layer, the minima in the vertical temperature profile and the vertical temperature gradient are interpreted. On the basis of analysis of gravitational potential field, the geostrophic current and the geostrophic volume transport are calculated to determine the location of the strongest current in the zonal circulation near the Prydz Bay and to find the spatial variability of the volume transport in the64° -66.5°S zone. In addition, the central location, the frontal strength, the vertical depth and thickness of the continental water boundary （CWB） are estimated from the CTD data to expound the spatial variability of CWB in the study area （64° -66.5°S, 70° -75°E）.

Silicon limitation on primary production and its destiny in Jiaozhou Bay, China VI: The ecological variation process of the phytoplankton

The combination effect of light, water temperature and nutrients on phytoplankton growth in Jiaozhou Bay is studied in this paper. The order of importance of the influence on phytoplankton growth is de- termined as nutrients, water temperature, and light. The influence of these factors unveiled the mechanism of the influence, and revealed the variation process of the nutrients limiting phytoplankton primary production, and of the water temperature influencing the phytoplankton reproduction capacity, and hence influencing the structure of phytoplankton assemblage. Temporal and spatial quantification shows different stages of the influence by wa- ter temperature and nutrients on the phytoplankton growth. Moreover, the authors expatiated the ideal state of the phytoplankton growth and the reason of red tide occurrence. People should consider in their activity the input of nutrient Si first, and then the variation of water temperature, advocating sustainable development manner.

Numerical analysis on water exchange and its response to the coastal engineering in the Yueqing Bay in China

On the basis of a numerical model of tidal current using Delft3D , the distribution of the semi-exchange time of water was simulated in the Yueqing Bay here. The result showed that the semi-exchange time was about more than 6 d in the bay end, and about 1~2 d in the bay mouth. Besides, based on the calculation of the semi-exchange time before and after the Xuanmen Dam project, a comparison between them was further carried out. And the same work was also done with the recent reclamation projects in the Yueqing Bay as well. The results showed that the change in semi-exchange time caused by the Xuanmen Dam project was about 6 d increase near the dam and 4.5 d increase at the bay end. And it was about 5 d increase at the bay end and 1 d increase at the mouth of the bay caused by the recent reclamation projects.

Environmental Drivers of Temporal and Spatial Fluctuations of Mesozooplankton Community in Daya Bay, Northern South China Sea

The response of zooplankton to the ecological environment in Daya Bay is unclear under the influence of both climate changes and anthropogenic activities on a seasonal to inter-annual scale.Based on monthly surveys and historical data,we found the zooplankton community had changed temporally and spatially.A total of 134 species was recorded during the study,and copepods dominated numerically in terms of diversity and abundance.Both copepods and cladocerans were the main contributors to zooplankton abundance.The community structure of zooplankton was temporally classified into the warm and cold groups,and spatially into the three groups located in the marine cage-culture area(MCCA),the outflow of nuclear power plants(ONPP)and unpolluted waters(UPW).The zooplankton was characterized by low biomass(dry weight),high diversity and abundance in the warm period in contrast to that in the cold period.Compared with the other two groups,the MCCA group of zooplankton showed high abundance,low diversity and biomass.Variations in dominant species were closely related to temperature,salinity and chlorophyll a concentration.Species diversity and dry weight decreased in comparison with 30 years ago,while zooplankton abundance increased.The seasonal variation in zooplankton was affected mainly by temperature that was controlled by monsoon,while the spatial difference in the community structure was probably due to eutrophication in the MCCA and thermal water discharge from ONPP.The zooplankton community is undergoing great changes with the tendency of miniaturization and gelatinization in recent 30 years in Daya Bay.