Estimates of autumntime benthic secondary production in Laizhou Bay and adjacent Bohai Sea waters

The whole metazoan community inhabiting Laizhou Bay and adjacent Bohai Sea waters were sampled in late autumn,2006.Secondary production estimates for macrofauna and meiofauna were made separately.Total benthic secondary production was as high as 8.38 ± 4.08 g ash-free dry weight(AFDW) m-2 a-1,which represented the autumn production level.In general,macrofaunal secondary production in Laizhou Bay was much lower than that in adjacent Bohai Sea areas.In contrast,meiofaunal secondary production in Laizhou Bay was higher than that in adjacent Bohai Sea areas.Macrofauna contributed 61% to benthic secondary production(5.09 ± 3.26 g AFDW m-2 a-1),lower than the value in previous studies in Bohai Sea.Sediment granulometric characteristics and bottom-water salinity could explain the substantial variability in the macrofauna biomass and production.Meiofaunal production was an important component of benthic production and exceeded macrofauna production under exceptional conditions,e.g.in Laizhou Bay,where macrofauna was restricted.Chlorophyll pigments(Chl-a) concentrations in sediment explained the general meiofaunal biomass and production distribution here.     

Taxonomic distinctness of macrofauna as an ecological indicator in Laizhou Bay and adjacent waters

In this paper, we assessed the ecological and biodiversity status in the Bohai Sea through a quantitative survey on mac-rofaunal community at 25 stations in Laizhou Bay and adjacent waters in the autumn of 2006.We tested the robustness and effectiveness of taxonomic distinctness as an ecological indictor by analyzing its correlation with species richness and natural environmental variables and by analyzing other ecological indicators (Shannon-Wiener H' and W statistics from Abundance Biomass Comparison curve).Results so obtained indicated that the benthic environment of the study waters in general is not under major impact of anthropogenic disturbance, but some stations in Laizhou Bay and along the coast of the Shandong Peninsula and even in the central Bohai Sea might be moderately disturbed and showed signs of ecological degradation.The taxonomic distinctness measures △+ and Λ+ were independent of sampling effort and natural environment factors and were compliant to other ecological indicators.Further application of the taxonomic distinctness indicator to assess marine biodiversity and ecosystem health on a larger regional scale with historical data seems promising.     

Changes in nitrogen and phosphorus and their effects on phytoplankton in the Bohai Sea

Systematic studies of the changes in dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) and their effects on phytoplankton over the last 30 years in the Bohai Sea are presented. The amount of sewage disposal, use of fertilizer and the Huanghe River runoff were found to have a significant influence on the DIN or DIP concentrations in the Bohai Sea over the last 30 years. Moreover, the changes in DIN and DIP resulted in changes in the limiting nutrients of phytoplankton in the Bohai Sea from nitrogen in the early 1980s to nitrogen-phosphorus in the late 1980s, and then to phosphorus after the 1990s. In addition, changes in nitrogen and phosphorus had a significant effect on the phytoplankton community structure. The half saturation constant (K _s) was used to evaluate the effect of nutrients on the phytoplankton community structure in the Bohai Sea over the last 30 years. Cell abundance percentages of dominant phytoplankton species with high K _s values for phosphorus and low K _s values for nitrogen have decreased since the 1980s, while those of dominant phytoplankton species with low K _s values for phosphorus and high K _s values for nitrogen increased during this period.     

Foraminiferal Changes and Response to the Channel Diversion and Discharge Fluctuation of the Yellow River in the North Yellow Sea During the Past Century

Diversion of the Yellow River is a unique geological event in offshore China, causing changes of the sedimentary environment in eastern China Seas. The last diversion took place in AD 1855, with the estuary diverted from the Yellow Sea into the Bohai Sea. The identification of the river diversion events in the shelf sediments would not only provide the definite ages for the sediments, but also give a clue for better understanding of the sedimentation in that area. In this study, 210 Pb, grain size, geochemical element, and foraminiferal data in core H205 from the north Yellow Sea were systematically investigated. A high-resolution sedimentary record was established, which was coupled with the Yellow River diversion and runoff changes. The results show that the foraminiferal composition and foraminiferal abundance of the sediments from the north Yellow Sea had good response to the Yellow River diversion in 1855. Before the change, shallow water assemblages dominated the foraminifera, and the abundance of each foraminiferal species was very low. After the diversion event, the abundance of most foraminifera increased sharply, with a maximum increase of 16 times, and the assemblage was still dominated by shallow water species. Furthermore, the changes in foraminiferal abundance in the core sediments corresponded well with the discharge fluctuation of the Yellow River since 1855. When the Yellow River began entering the Bohai Sea, the Yellow River water, which is rich in nutrients, along with the coastal currents affected the north Yellow Sea, increased the primary productivity in the north Yellow Sea, which is the main reason for the abrupt increase and fluctuation of foraminiferal abundance in this area. At the meantime, the East Asian winter monsoon could also promote the development of nearshore foraminiferal species by enhancing the coastal currents.     

SHORT TIME DYNAMICS OF CILIATE ABUNDANCE IN THE BOHAI SEA （CHINA）

The ciliate community in the Bohai Sea (China) was studied from 23 September to 7 October 1998. A hurricane struck the study area between the two grid station investigations, which were six days apart. Six tintinnid species ( Favella panamensis, Leptotintinnus nordqvisti, Tintinnopsis but-schlii, T. karajacensis , T. Radix and Wangiella dicollaria ) were identified. Total cililate abundance in the surface layer ranged from 20 to 770 ind/l. In the first grid investigation, Tintinnopsis karajacensis dominated in the warm, low salinity waters at the Huanghe River mouth. Aloricate ciliate sp. 1 dominated in the cold, high salinity waters in the northwest of the study area and the Bohai Strait. In the second grid investigation, T. Karajacensis almost disappeared. The abundance of aloricate ciliate sp. 1 decreased drastically. The aloricate ciliate sp. 2 dominated at the Bohai Strait. The change of ciliate abundance may be due to the disturbance of hurricane.     

Distribution and abundance of pelagic tunicates in the North Yellow Sea

In this paper, the distribution patterns and abundance of pelagic tunicates in the North Yellow Sea of China during the period 2006-2007 were analyzed. Zooplankton samples were obtained with vertical towing from bottom to surface using a WP2 plankton net(200 μm mesh size; mouth area: 0.25 m2). Five species belonging to two classes were identified: Oikopleura dioica, O. longicauda and Fritillaria borealis belonging to class Appendicularia; Salpa fusiformis and Doliolum denticulatum of class Thaliacea. O. dioica and O. longicauda were the dominant species, occurring in the samples of all four seasons, with different distribution patterns. Their maximum abundance were 1664.7 ind. m-3(spring) and 1031.7 ind. m-3(spring) respectively. Following Oikopleura spp. were D. denticulatum, which was found only in autumn with an average abundance of 149.6 ind. m-3, and S. fusiformis, which was detected all the year long except for autumn with low abundance(max. abundance 289.4 ind. m-3 in summer). Only a very small amount of F. borealis was detected in summer samples, with an average abundance of 2.7 ind. m-3. The relationship between tunicates abundances and the environmental factors was analyzed using the stepwise regression model for each species. The variation of appendicularian abundance showed a significant correlation with the surface water temperature and with the concentration of Chl-a. No relationship was found between tunicates abundance and salinity, likely due to the slight changes in surface salinity of the studied area during the four seasons. Salps abundance and that of doliolids were significantly correlated to bottom water temperature, indicating that these two species(S. fusiformis and D. denticulatum) migrate vertically in the water column. In particular D. denticulatum, known to be a warm water species, showed not only an important correlation with water temperature, but also a spatial distribution connected to the warm currents in the North Yellow Sea. The occurrence of D. denticulatum represents an interesting result never found in past research work. Water temperature, algal distribution and currents were the most relevant environmental factors influencing the tunicate abundance and distribution in the North Yellow Sea. Further research is needed in order to get more information on the ecology of these organisms and to better understand their role in the ecosystem including the oceanic food web.     

The observed currents in summer in the Bohai Sea

A harmonic method was used to analyze the tidal currents observed in summer at 11 stations made from 1996 to 2001 in the Bohai Sea, China. Data was compared among different instruments and intervals. Elliptic elements were calculated based on harmonic constants, of which vertical distributions of the maximum speed and rotation direction were discussed for understanding the characteristics of diurnal and semi-diurnal tidal current components. The results indicate that the maximum speed of M2 tidal current component is much larger than that of K1; the rotation direction of M2 tidal current constituent is clockwise in the central part of the Bohai Sea and in the Laizhou Bay, but anticlockwise in the Liaodong Bay and Bohai Bay. For K1 tidal current constituent, it is clockwise in the central Bohai Sea but anti-clockwise in the Laizhou Bay and Liaodong Bay. The tidal currents in most stations in the Bohai Sea were regular semidiurnal except for those in the central Bohai Sea, being irregular semidiurnal.     

Genetic improvement on Chinese shrimp （Fenneropenaeus chinensis）： growth and viability performance in F1 hybrids of different populations

Fenneropenaeus chinensis distributed in the Yellow Sea and Bohai Sea of China and the west coast of the Korean Peninsula. Different geographical populations represent potentially different genetic resources. To learn further the characteristics of different geographical population, crosses among two wild and three farmed populations were produced. The two wild populations were from the Yellow Sea and Bohai Sea (WYP), and the west coast of the Korean Peninsula and coast (WKN). The three farmed populations included the offspring of first generation of wild shrimp from coast in Korea (FKN), the Huang Hai (the Yellow Sea in Chinese) No. 1 (HH 1), and JK98. The phenotypes growth and survival rates of these populations were compared to confirm the feasibility for crossbreeding. The body length (BL), carapace length (CL), carapace width (CW), height of the second and third abdominal segment (HST), width of the second and third abdominal segment (WST), length of the first abdominal segment (LF), length of the last abdominal segment (LL), live body weight (BW), and survival rate were measured. Different combinations were statistically performed with ANOVA and Duncan's Multiple significant difference (P<0.05) in BL, CL, HST, LL, and BW; and insignificant difference (P0.05) in other growth traits and survival rate. The results of Duncan's Multiple Range Test are that BL and CL of was the best combination in all growth traits. Therefore, hybridization can introduce the variation to base populations. The systematic selection program based on additive genetic performance may be more effective than crossbreeding.     

Fouling acorn barnacles in China—a review

We review the species composition,distribution, and seasonal variation of fouling acorn barnacles in Chinese waters-from Bohai Sea and Yellow Sea to East and South China Seas. Thirty-two species of acorn barnacles were found, of which, the dominant species are Amphibalanus amphitrite, A. reticulatus, A. variegates, Balanus trigonus, Fistulobalanus kondakovi, Megabalanus tintinnabulum, Striatobalanus amaryllis, and Eurapha withersi in the fouling communities. A. amphitrite is the dominant species in the coastal waters of Bohai Sea and Yellow Sea and A. reticulatus is dominant in the East and South China Seas. The settlement period of fouling acorn barnacles is usually in summer and autumn. From north to south with the decrease of latitude, their settlement period obviously extends, even to the whole year, and the species number also increases.0ther environmental factors, such as salinity and distance from shore, also play an important role in the distribution of fouling acorn barnacles.     

渤海郯庐断裂西支构造特征及对潜山形成的控制作用

渤海郯庐断裂西支是指郯庐断裂渤海段西侧分支断层,其形成演化对前新生代地层展布和潜山构造发育具有重要控制作用。基于三维地震、钻井、分析化验等资料,对渤海郯庐断裂西支构造特征、成因演化模式,以及对潜山形成的控制作用进行了分析。研究表明:①渤海郯庐断裂西支具有印支期、燕山早期、燕山中期、喜山早期多期叠加活动的特征,喜山晚期活化作用弱,整体隐伏于新生代沉积物之下;②渤海郯庐断裂西支具有显著的分段性,被近东西向断裂分割成北、中、南3段,各段在关键地质时期构造变形型式和强度存在一定差异;③印支期不均一南北向挤压所导致的走滑转换是渤海郯庐断裂西支的启动机制;④渤海郯庐断裂西支在印支期-燕山早期走滑逆冲活动及伴生褶皱是控制潜山地层展布及渤中19-6等潜山构造形成的关键因素。研究成果可以为渤海海域的油气勘探提供基础。      

Interannual Variability and Scenarios Projection of Sea Ice in Bohai Sea Part I: Variation Characteristics and Interannual Hindcast

The Bohai Sea is one of the southernmost areas for sea ice formation in the northern hemisphere.Sea ice disasters in this body of water severely affect marine activities and the safety of coastal residents.In this study,we analyze the variation characteristics of the sea ice in the Bohai Sea and establish an annual regression model based on predictable mode analysis method.The results show the following:1)From 1970 to 2018,the average ice grade is(2.6±0.8),with a maximum of 4.5 and a minimum of 1.0.Liaodong Bay(LDB)has the heaviest ice conditions in the Bohai Sea,followed by Bohai Bay(BHB)and Laizhou Bay(LZB).Interannual variation is obvious in all three bays,but the linear decreasing trend is significant only in BHB.2)Three modes are obtained from empirical orthogonal function analysis,namely,single polarity mode with the same sign of anomaly in all of the three bays and strong interannual variability(82.0%),the north–south dipole mode with BHB and LZB showing an opposite sign of anomalies to that in LDB and strong decadal variations(14.5%),and a linear trend mode(3.5%).Critical factors are analyzed and regression equations are established for all the principal components,and then an annual hindcast model is established by synthesizing the results of the three modes.This model provides an annual spatial prediction of the sea ice in the Bohai Sea for the first time,and meets the demand of operational sea ice forecasting.     

On the 2-crop culture of penaeid shrimps

Although much progress has been made in the last few years on the hatchery rearing of penaeid shrimps, the use of artificial feeds and the innovation of culture techniques, the key problem in the shrimp culture industry is still to increase yield per unit culture area for greater economic returns. In finding an answer to this problem, experiments on the cultivation of two (instead of one) species with different biological requirements were carried out in different seasons,Penaeus orientalis Kishinouye in spring andP. penicillatus Alcock in summer in Fujian as it has a longer culture season. Years of study and practical experience in large-scale rearing of shrimps show that successive 2-crop culture of penaeid shrimps is feasible and more economical as no additional investment in terms of maintenance facilities and management is needed. The pond is fully used the whole year. The renovation of techniques and the timing of the culture of the two species led to the development of a 2-crop culture method which roughly doubled the yield per unit area of cultivation. The early season species is harvested at the prime of its development and the culture of the late season species begin just after the harvest of the early season species.     

改进DINEOF算法在中国渤海叶绿素a遥感缺失数据重构中的应用研究

叶绿素a（chl-a）是重要的海洋环境水色参数,但是受云雾覆盖的影响,卫星遥感chl-a产品中普遍存在数据缺失的现象,大大降低了数据的应用效果。经验正交函数插值方法（DINEOF）是目前在长时间序列缺失数据重构方面应用最广泛的数据插值重构方法,本研究针对DINEOF方法在空间小尺度上过度平滑的缺陷,设计了一种面向渤海chl-a的分层重构方法（SDS-DINEOF）,该方法重点考虑了渤海chl-a分布呈现近岸高、中部低的规律,将渤海海域等距离分为32个区域,对位于每个区域的子数据集分别进行重构;利用该方法对2019年全年每日10时13分的渤海GOCI卫星chl-a产品进行了重构,并将其重构结果与DINEOF重构结果进行了对比分析。分析结果表明：应用SDS-DINEOF方法相比DINEOF方法,chl-a重构精度和时间效率上均得到了提升,其中整体精度提高了3.52%,重构时间节约了125%,尤其是在距离陆地最远的渤海中部区域,应用该方法重构精度提升最为显著。本文取得的研究结果对于海洋遥感数据产品的质量提高和应用效率的提升,具有较为重要的理论意义和实际应用价值。     

Summertime community structure of intertidal macrobenthos in Changdao Archipelago,Shandong Province,China

The community structure of intertidal macrobenthos in Changdao Archipelago(north of Shandong Peninsula,between Bohai Bay and the northern Yellow Sea) was examined based on samples collected from 14 stations in five transects in June 2007.Three stations corresponding to high,medium and low tidal areas were set up for each transect.A total of 68 macrobenthic species were found in the research region,most of which belonged to Mollusca and Crustacea.The average abundance and biomass of the macrobenthos was 1 38...     

Interpretation of sea surface wind interannual vector EOFs over the China seas

Using interpolation and averaging methods, we analyzed the sea surface wind data obtained from December 1992 to November 2008 by the scatterometers ERS-1, ERS-2, and QuikSCAT in the area of 2°N–39 °N, 105°E–130°E, and we reported the monthly mean distributions of the sea surface wind field. A vector empirical orthogonal function (VEOF) method was employed to study the data and three temporal and spatial patterns were obtained. The first interannual VEOF accounts for 26% of the interannual variance and displays the interannual variability of the East Asian monsoon. The second interannual VEOF accounts for 21% of the variance and reflects the response of China sea winds to El Niño events. The temporal mode of VEOF-2 is in good agreement with the curve of the Niño 3.4 index with a four-month lag. The spatial mode of VEOF-2 indicates that four months after an El Niño event, the southwesterly anomalous winds over the northern South China Sea, the East China Sea, the Yellow Sea, and the Bohai Sea can weaken the prevailing winds in winter, and can strengthen the prevailing winds in summer. The third interannual VEOF accounts for 10% of the variance and also reflects the influence of the ENSO events to China Sea winds. The temporal mode of VEOF-3 is similar to the curve of the Southern Oscillation Index. The spatial mode of VEOF-3 shows that the northeasterly anomalous winds over the South China Sea and the southern part of the East China Sea can weaken the prevailing winds, and southwesterly anomalous winds over the northern part of the East China Sea, the Yellow Sea, and the Bohai Sea can strengthen the prevailing winds when El Niño occurs in winter. If El Niño happens in summer, the reverse is true.     

MASS BALANCES OF MAJOR CHEMICAL CONSTITUENTS IN BOHAI SEA WATER Ⅱ.REMOVAL PROCESSES

The removal processes of major seawater chemical constituents in the Bohai Sea include seawater ex-change between the Bohai Sea and the Northern Yellow Sea,cation exchange,interstitial water burialand spray,formation of illite,sepiolite,sulfate and sulfur,and carbonates.The mass balance calculationbased on these processes is very applicable to the Bohai Sea.     

Long-term variation of storm surge-associated waves in the Bohai Sea

When investigating the long-term variation of wave characteristics as associated with storm surges in the Bohai Sea, the Simulating Waves Nearshore(SWAN) model and ADvanced CIRCulation(ADCIRC) model were coupled to simulate 32 storm surges between 1985 and 2014. This simulation was validated by reproducing three actual wave processes, showing that the simulated significant wave height(SWH) and mean wave period agreed well with the actual measurements. In addition, the long-term variations in SWH, patterns in SWH extremes along the Bohai Sea coast, the 100-year return period SWH extreme distribution, and waves conditional probability distribution were calculated and analyzed. We find that the trend of SWH extremes in most of the coastal stations was negative, among which the largest trend was-0.03 m/a in the western part of Liaodong Bay. From the 100-year return period of the SWH distribution calculated in the Gumbel method, we find that the SWH extremes associated with storm surges decreased gradually from the center of the Bohai Sea to the coast. In addition, the joint probability of wave and surge for the entire Bohai Sea in 100-year return period was determined by the Gumbel logistic method. We therefore, assuming a minimum surge of one meter across the entire Bohai Sea, obtained the spatial SWH distribution. The conclusions of this study are significant for offshore and coastal engineering design.     

NUMERICAL SIMULATION AND DYNAMIC STUDY OF THE WINTERTIME CIRCULATION OF THE BOHAI SEA

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