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We measured dissolved methane (CH4) concentrations, saturations, and fluxes from sea into air and from sediment into water during cruises in March, May, August, October, and December of 2011 in the East China Sea (ECS) and the Yellow Sea (YS). CH4 concentrations had obvious spatial and seasonal variability due to the complex effects of different water masses and other variables. Maximal CH4 concentration, sea-air and sediment-water fluxes all occurred during the summer. CH4 concentration decreased gradually from the coastal area to the open sea, and high levels of CH4 generally appeared near the Changjiang Estuary and outside the Hangzhou Bay. During early spring and winter, CH4 had a uniform distribution from the surface to the bottom, but CH4 concentration increased gradually with depth during other seasons. The subsurface CH4 maximum occurred at a depth of about 200 m during May, October, and December. The CH4 level at the bottom was generally higher than at the surface, and this was enhanced during summer due to hypoxia in the bottom waters. Changjiang-diluted water, the Kuroshio Current, and the Taiwan Warm Current Water affected the geographic distribution of CH4 in the ECS, and these water bodies contributed about 3.45, 2.97, 14.60mols-1 of CH4 during summer and 2.11, 8.58, 5.20 mols-1 CH4 during winter, respectively. Sediment was also a significant source of dissolved CH4 in the ECS, and we estimated the average sediment-water CH4 flux of the ECS and YS as about 1.02 μmolm-2d-1. We also used a box model to calculate the CH4 budget in the ECS. The results suggested that in situ CH4 production in the water column was the major source of CH4, and accounted for 0.21 μmol m-3 day-1 during summer and 0.11 μmol m-3 day-1 during winter. Air-sea exchange was the major sink of CH4 in the ECS. We estimated total CH4 emission from the ECS and YS as about 4.45 x 109 mol during 2011. Our results indicated that the ECS and YS were active areas for CH4 production and emission. [ABSTRACT FROM AUTHOR]

In order to investigate the mechanism of spatial dynamics of picoplankton community (bacteria and Synechococcus spp.) and estimate the carbon flux of the microbial food web in the oligotrophic Taiwan Warm Current Water of subtropical marine pelagic ecosystem, we conducted size-fractionation experiments in five cruises by the R/V Ocean Research II during the summers of 2010 and 2011 in the southern East China Sea. We carried out culture experiments using surface water which, according to a temperature-salinity (T-S) diagram, is characterized as oligotrophic Taiwan Current Warm Water. We found a negative correlation between bacteria growth rate and temperature, indicating that the active growth of heterotrophic bacteria might be induced by nutrients lifted from deep layer by cold upwelling water. This finding suggests that the area we studied was a bottom-up control pelagic ecosystem. We suggest that the microbial food web of an oligotrophic ecosystem may be changed from top-down control to resource supply (bottom-up control) when a physical force brings nutrient into the oligotrophic ecosystem. Upwelling brings nutrient-rich water to euphotic zone and promotes bacteria growth, increasing the picoplankton biomass which increased the consumption rate of nanoflagellate. The net growth rate (growth rate--grazing rate) becomes negative when the densities of bacteria and Synechococcus spp. are lower than the threshold values. The interaction between growth and grazing will limit the abundances of bacteria (105 -106 cells mL -1) and Synechococcus spp. (104 -105 cells mL-1) within a narrow range, forming a predator-prey eddy. Meanwhile, 62% of bacteria production and 55% of Synechococcus spp. production are transported to higher trophic level (nanoflagellate), though the cascade effect might cause an underestimation of both percentages of transported carbon. Based on the increasing number of sizes we found in the size-fractionation experiments, we estimated that the predation values were underestimated by 28.3% for bacteria and 34.6% for Synechococcus spp. Taking these corrections into consideration, we conclude that picoplankton production is balanced by nonoflagellate grazing and the diet of nanoflagellate is composed of 64% bacteria and 36% Synechococcus spp. [ABSTRACT FROM AUTHOR]

This study was designed to determine the effects of flooding on plankton community respiration (CR) in the East China Sea (ECS). In July 2010, a devastating flood occurred in the Changjiang River; the mean monthly discharge was 60 527m³ s-1. To compare, the variables were also examined in the low riverine flow of July 2009 (33 955 m³ s-1). During the flooding, the Changjiang diluted water (CDW) zone, the sea surface salinity (SSS) was ≤ 31 psu, covering almost two thirds of the ECS, which was approximately six times that in the non-flooding period. The mean nitrate concentration was higher in 2010 (6.2 µM) than in 2009 (2.0 µM). However, in the 2010 flood, the mean values of Chl a and the bacterial biomass were only slightly higher or even lower than in 2009. Surprisingly, however, the CR was still higher in the flood period than in the non-flood period, with mean values of 105.6 and 73.2mg C m-3 d-1, respectively. The higher CR in 2010 could be attributed to vigorous plankton activities, especially phytoplankton, at stations in the CDW zone, which were not mostly covered by low SSS in 2009. There was a huge amount of fCO2 drawdown in the 2010 flood. These results suggested that the devastating flood in 2010 had a significant effect on the carbon balance in the ECS. This effect might become more pronounced as extreme rainfall events and flooding magnitudes increase dramatically throughout the world. [ABSTRACT FROM AUTHOR]

A total of 8459 larval fish were collected in the southern East China Sea during the winter northeasterly monsoon season and the summer southwesterly monsoon seasons in 2008. They were composed of 184 species belonging to 105 families and 162 genera. The abundance in terms of CPUE (number of individuals/1000m³) of the larvae was about six times higher in the southwesterly monsoon season than that in the northeasterly monsoon season. The primary environmental factors affecting the larval abundance were found to be water temperature in the northeasterly monsoon season but food availability in the southwesterly monsoon season. Three larval fish assemblages were recognized; the inshore assemblage, the offshore assemblage, and the summer coastal assemblage. The distribution and species composition of the larvae in the assemblages reflected the hydrographic conditions and water currents resulted from the seasonal monsoons. [ABSTRACT FROM AUTHOR]

Typhoons can induce vertical mixing, upwelling, or both in the water column due to strong wind stress. These events can induce phytoplankton blooms in the oligotrophic ocean after typhoon passage. However, little is known about the responses of lower trophic-level organisms or changes in the community structure following the passage of typhoons, particularly in offshore regions. Therefore, we evaluated community succession on the outer shelf of the East China Sea through on-deck bottle incubation experiments simulating hydrographic conditions after the passage of a typhoon. Under all of the experimental conditions we tested, chlorophyll a concentrations increased more than 9-fold within 6 days, and these algal cells were mainly composed of large diatoms (>10 µm). Ciliates also increased along with the diatom bloom. These results suggest that increases in diatom and ciliate populations may enhance biogenic carbon export in the water column. Typhoons can affect not only phytoplankton productivity, but also the composition of lower trophic-level organisms and biogeochemical processes in oligotrophic offshore regions. [ABSTRACT FROM AUTHOR]

Benthic nitrogen transformation pathways were investigated in the sediment of the East China Sea in June of 2010 using the 15N isotope pairing technique. Slurry incubations indicated that denitrification, anammox and dissimilatory nitrate reduction to ammonium (DNRA) as well as nitrate release by nitrate storing organisms occurred in the East China Sea sediments. These four processes did not exist independently, the nitrate release therefore diluted the 15N labeling fraction of NO3-, a part of the 15NH4+ derived from DNRA also formed 30N2 via anammox. Therefore current methods of rate calculations led to over and underestimations of anammox and denitrification respectively. Following the procedure outlined in Thampdrup and Dalsgaard (2002), denitrification rates were slightly underestimated by on average 6 % without regard to the effect of nitrate release, while this underestimation could be counteracted by the presence of DNRA. On the contrary, anammox rates calculated from 15NO3- experiment were significantly overestimated by 42% without considering nitrate release. In our study this overestimation could only be compensated 14% by taking DNRA into consideration. In a parallel experiment amended with 15NH4+ 14NO3-, anammox rates were not significantly influenced by DNRA due to the high background of 15NH4+ addition. Excluding measurements in which bioirrigation was present, integrated denitrification rates decreased from 10 to 4mmolNm-2d-1 with water depth, while integrated anammox rates increased from 1.5 to 4.0 mmolNm-2. Consequently, the relative contribution of anammox to the total N-loss increased from 13% at the shallowest site near the Changjiang estuary to 50% at the deepest site on the outer shelf. This study represents the first time in which anammox has been demonstrated to play a significant role in benthic nitrogen cycling in the East China Sea sediment, especially on the outer shelf. N-loss as N-1 was the main pathway, while DNRA was also an important pathway accounting for 20-31 % of benthic nitrogen transformation in the East China Sea. Our study demonstrates the complicated interactions among different benthic nitrogen transformations and the importance of considering denitrification, DNRA, anammox and nitrate release together when designing and interpreting future studies. [ABSTRACT FROM AUTHOR]2 was the main pathway, while DNRA was also an important pathway accounting for 20-31 % of benthic nitrogen transformation in the East China Sea. Our study demonstrates the complicated interactions among different benthic nitrogen transformations and the importance of considering denitrification, DNRA, anammox and nitrate release together when designing and interpreting future studies. [ABSTRACT FROM AUTHOR]

To better understand carbon cycling in marginal seas, particulate organic carbon (POC) concentrations, POC fluxes and primary production (PP) were measured in the East China Sea (ECS) in summer 2007. Higher concentrations of POC were observed in the inner shelf and lower POC values were found in the outer shelf. Similar to POC concentrations, elevated uncorrected POC fluxes (720-7300mgCm-2 d-1) were found in the inner shelf and lower POC fluxes (80-150mgCm-2 d-1) were in the outer shelf, respectively. PP values (~340-3380mgCm-2 d-1) had analogous distribution patterns to POC fluxes, while some of PP values were significantly lower than POC fluxes, suggesting that contributions of resuspended particles to POC fluxes need to be appropriately corrected. A vertical mixing model was used to correct effects of bottom sediment resuspension and the corrected POC fluxes ranging from 41±20 to 956±443mgCm-2 d-1, which were indeed lower than PP values. The results suggest that 49-93% of the POC flux in the ECS might be from the contribution of resuspension of bottom sediments rather than from the actual biogenic carbon sinking flux. While the vertical mixing model is not a perfect model to solve sediment resuspension because it ignores biological degradation of sinking particles, Changjinag plume (or terrestrial) inputs and lateral transport, it makes significant progress in both correcting resuspension problem and in assessing a reasonable quantitative estimate in a marginal sea. [ABSTRACT FROM AUTHOR]

Allometric scaling of body size versus growth rate and mortality has been suggested to be a universal macroecological pattern, as described by the Metabolic Theory of Ecology (MTE). However, whether such scaling generally holds in natural assemblages remains debated. Here, we test the hypothesis that the size-specific growth rate and grazing mortality scales with the body size with an exponent of -1/4 after temperature correction, as MTE predicts. To do so, we couple the dilution experiment with the FlowCAM imaging system to obtain size-specific growth rates and grazing mortality of natural microphytoplankton assemblages in the East China Sea. This novel approach allows us to achieve highly resolved size-specific measurements that could be hardly obtained in traditional size-fractionated measurements using filters. Our results do not support the MTE prediction. The size-specific growth rates scale positively with body size (with scaling exponent ~0.1), and the size-specific grazing mortality is independent of body size. Furthermore, results of path analysis indicate that size-specific grazing mortality is mainly determined by size-specific growth rate. We further investigate how the variation of size-specific growth rate and grazing mortality can interact to determine the microphytoplankton size structure, described by Normalized Biomass Size Spectrum (NB-SS). We test if the variation of microphytoplankton NB-SS slopes is determined by (1) differential grazing mortality of small versus large individuals, (2) differential growth rate of small versus large individuals, or (3) combinations of these scenarios. Our results indicate that the relative grazing mortality of small over large size category best explains the variation of NB-SS slopes across environments. These results suggest that higher grazing mortality of small microphytoplankton may release the large phytoplankton from grazing, which in turn leads to a flatter NB-SS slope. This study contributes to an understanding of the relative importance of bottom-up versus top-down control in shaping the microphytoplankton size structure. [ABSTRACT FROM AUTHOR]

A tremendous amount of organic carbon respired by planktonic communities has been found in summer in the East China Sea (ECS), and this rate has been significantly correlated with fluvial discharge from the Changjiang River. However, data related to this issue in other seasons have rarely been collected. To evaluate and reveal the potential controlling mechanism of organic carbon consumption in spring in the ECS, research using stations covering almost the entire ECS shelf was conducted in the spring of 2009 and 2010. During both periods, the fluvial discharges were similar, and these rates were comparable to high riverine flow in summer. Interestingly, planktonic community respiration (CR) varied widely in both springs; in 2009, the level of CR was double that of 2010, with mean (±SD) values of 111.7 (±76.3) and 50.7 (±62.9)mgCm-3 d-1 , respectively. The CR was positively linearly regressed with concentrations of particulate organic carbon and/or chlorophyll a (Chl a) in 2009 (all p < 0.01). These results suggest that the rate was dependent on planktonic activities, especially that of phytoplankton, in 2009. During this period, phytoplankton growth flourished due to allochthonous nutrients discharged from the Changjiang River. Furthermore, higher phytoplankton growth leaded to the absorption of an enormous amount of fugacity of CO2 (fCO2) in the surface waters, even with a significant amount of inorganic carbon regenerated via CR. In 2010, there were even more riverine runoff nutrients into the ECS than in 2009. Surprisingly, the growth of phytoplankton in 2010 was not stimulated by enriched nutrients, and its growth was likely limited by low water temperature and/or low light intensity. Low temperature might also suppress planktonic metabolism, and this could explain why the CR was lower in 2010. During this period, lower surface water fCO2 might have mainly been driven by physical process(es). To conclude, these results indicate that organic carbon consumption (i.e. CR) in the ECS in spring might be controlled by the magnitude of planktonic activities and physical factor (e.g. temperature), and that the latter is especially important during a cold spring season. This further suggests that the high intraseasonal variability of organic carbon consumption needs to be kept in mind when budgeting the annual carbon balance. [ABSTRACT FROM AUTHOR]

Zooplankton play an essential role in marine food webs and understanding how community-level growth rates of zooplankton vary in the field is critical for predicting how marine ecosystem function may vary in the face of environmental changes. Here, we used the artificial cohort method to examine the effects of temperature, body size, and chlorophyll concentration (a proxy for food) on weight-specific growth rates for copepod communities in the East China Sea. Specifically, we tested the hypothesis that copepod community growth rates can be described by the metabolic theory of ecology (MTE), linking spatio-temporal variation of copepod growth rate with temperature and their body size. Our results generally agree with predictions made by the MTE and demonstrate that weight-specific growth rates of copepod communities in our study area are positively related with temperature and negatively related to body size. However, the regression coefficients of body size do not approach the theoretical predictions. Furthermore, we find that the deviation from the MTE predictions may be partly attributed to the effect of food availability (which is not explicitly accounted for by the MTE). In addition, significant difference in the coefficients of temperature and body size exists among taxonomic groups. Our results suggest that considering the effects of food limitation and taxonomy is necessary to better understand copepod growth rates under in situ conditions, and such effects on the MTE-based prediction needs further investigation. [ABSTRACT FROM AUTHOR]

Two sediment cores from the Changjiang (Yangtze) River estuary and its adjacent East China Sea were collected and studied for eutrophication history using paleoecological records of environmental changes over the last century. A multiproxy approach by using biological and geochemical analyses revealed changes in diatom assemblages, total organic carbon (TOC), total nitrogen (TN) and biogenic silica (BSi) and give an indication of nutrient in status and trends in Changjiang River estuary and its adjacent East China Sea. The diatom assemblages in the two cores generally increased gradually from the 1970s, and accelerated from the 1990s until now, reflecting the increased eutrophication and causing large algae blooms/red tides. The TOC, TN and BSi showing the similar trends, supported the interpretation of the eutrophication process indicated by diatom analyses. The two cores were located in different sea areas of the East China Sea, and we discuss their relative changes based on their environment characteristics. We also discuss the potential effect of anthropogenic influences and ongoing projects on eutrophication in the Changjiang River and its adjacent East China Sea. [ABSTRACT FROM AUTHOR]

Limited observations exist for reliable assessment of annual CO2 uptake that takes into consideration the strong seasonal variation in the river-dominated East China Sea (ECS). Here we explore seasonally representative CO2 uptakes by the whole East China Sea derived from observations over a 14yr period. We firstly identified the biological sequestration of CO2 taking place in the highly productive, nutrient-enriched Changjiang river plume, dictated by the Changjiang river discharge in warm seasons. We have therefore established an empirical algorithm as a function of sea surface temperature (SST) and Changjiang river discharge (CRD) for predicting sea surface pCO2. Synthesis based on both observation and model show that the annually averaged CO2 uptake from atmosphere during 1998-2011 was constrained to about 1.9mol C m-2yr-1. This assessment of annual CO2 uptake is more reliable and representative, compared to previous estimates, in terms of temporal and spatial coverage. Additionally, the CO2 time-series, exhibiting distinct seasonal pattern, gives mean fluxes of -3.0, -1.0, -0.9 and -2.5molC m-2yr-1 in spring, summer, fall and winter, respectively, and also reveals apparent inter-annual variations. The flux seasonality shows a strong sink in spring and a weak source in late summer-early fall. The weak sink status during warm periods in summer-fall is fairly sensitive to changes of pCO2 and may easily shift from a sink to a source altered by environmental changes under climate change and anthropogenic forcing. [ABSTRACT FROM AUTHOR]

Based on absolute geostrophic velocity calculated from repeated hydrographic data of 39 cruises from 2000 to 2009 and nitrate concentrations measured at the same sections from 1964 to 2011, we obtained temporally averaged nitrate flux (the product of velocity and nitrate concentration) and nitrate transport (integration of flux over a section) through 4 sections along the Kuroshio path from the East China Sea (sections PN and TK) to south of Japan (sections ASUKA and 137E). In addition, we examined section OK east of the Ryukyu Islands in order to understand the contribution of Ryukyu Current to the Kuroshio nutrient transport south of Japan. The mean nitrate flux shows a subsurface maximum core with a value of 10, 10, 11, 11, and 6 molm-2 s-1 at sections PN, TK, ASUKA, 137E, and OK, respectively. The depth of subsurface maximum core changes among five sections and is approximately 400, 500, 500, 400, and 800m at sections PN, TK, ASUKA, 137E, and OK respectively. The mean downstream nitrate transport is 199.3, 176.3, 909.2, 1385.5, and 341.2 kmolm-1 at sections PN, TK, ASUKA, 137E, and OK respectively. The nutrient transports at these sections suggest the presence of Kuroshio nutrient stream from its upstream region to downstream. The deep current structure of Ryukyu Current (section OK) makes it contribute more nitrate transport than the Kuroshio in the East China Sea (section TK) to the Kuroshio south of Japan. In addition, the positive difference between the downstream nitrate transport through section ASUKA and the sum of nitrate transports through sections TK and OK, as well as the positive difference of downstream nitrate transport between sections 137E and ASUKA, suggest that the Kuroshio recirculation significantly intensifies the downstream (eastward) nitrate transport by the Kuroshio. [ABSTRACT FROM AUTHOR]

To assess the impact of rising atmospheric CO2 and eutrophication on the carbonate chemistry of the East China Sea shelf waters, saturation states (Ω) for two important biologically-relevant carbonate minerals, calcite (Ωc) and aragonite (Ωa) were calculated throughout the water column from dissolved inorganic carbon (DIC) and total alkalinity (TA) data collected in spring and summer of 2009. Results show that the highest Ωc (~9.0) and Ωa (~5.8) values were found in surface water of the Changjiang plume area in summer, whereas the lowest values (Ωc =~2.7 and Ωa =~1.7) were concurrently observed in the bottom water of the same area. This divergent behavior of saturation states in surface and bottom waters was driven by intensive biological production and strong stratification of the water column. The high rate of phytoplankton production, stimulated by the enormous nutrient discharge from the Changjiang, acts to decrease the ratio of DIC to TA, and thereby increases Ω values. In contrast, remineralization of organic matter in the bottom water acts to increase the DIC to TA ratio, and thus decreases Ω values. The projected result shows that continued increases of atmospheric CO2 under the IS92a emission scenario will decrease Ω values by 40-50% by the end of this century, but both the surface and bottom waters will remain supersaturated with respect to calcite and aragonite. Nevertheless, superimposed on such Ω decrease is increasing eutrophication, which would mitigate or enhance the Ω decline caused by anthropogenic CO2 uptake in surface and bottom waters, respectively. Our simulation reveals that under the combined impact of eutrophication and augmentation of atmospheric CO2, the bottom water of the Changjiang plume area will become undersaturated with respect to aragonite (Ωa =~ 0.8) by the end of this century, which would threaten the health of the benthic ecosystem. [ABSTRACT FROM AUTHOR]

The East China Sea (ECS) and the South China Sea (SCS) are two major marginal seas of the north Pacific with distinct seasonal primary productivity. Based upon field observation in December 2008--January 2009 covering both the ECS and the northern SCS (NSCS) in wintertime, we examined southward long-range nutrient-transport from the ECS to the northeast SCS (NESCS) carried by the China Coastal Current (CCC) driven by the northeast prevailing monsoon. These nutrients escaped from the cold ECS shelf to refuel the primary production on the NESCS shelf where river-sourced nutrients were limited yet water temperature remained favorable. By coupling the field observation of nitrate+nitrite (DIN) with the volume transport of the CCC, we derived a first order estimate of DIN flux of ~1430±260mol s-1. This DIN flux was ~7 times the wintertime DIN input from the Pearl River, a primary riverine nutrient source to the NSCS. By assuming DIN was the limiting nutrient, such southward DIN transport would have stimulated ~8.8±1.6x1011 gC of new production (NP), accounting for ~>58±10% of the total NP or ~38±7-24±4% of primary production on the NESCS shelf shallower than 100 m. [ABSTRACT FROM AUTHOR]

Coastal areas adjoining rivers are nourished by both the riverborne nutrients and organic matters. Annually, the East China Sea (ECS) receives large quantities of particulate organic carbon transported from the Changjiang (Yangtze River), as well as nutrients, which have brought about high primary production in the ECS. This study evaluated the respective contributions of terrigenous organic matters (allochthonous food source) and nutrient-induced marine production (autochthonous food source) to the ECS benthic ecosystem by analyzing the stable isotope compositions for zooplankton, benthic crustacea and demersal fish. Zooplankton exhibited consistently higher δ13C values (-21.31‰~-19.22‰) in the inner shelf than in the outer shelf. The δ13C signals of fish (-19.64‰~-13.46‰) and crustacea (-18.87‰~-15.00‰) showed strong reliance on the marine production across the ECS continental shelf, regardless of distance from the shore. Moreover, the benthic crustacea and fish exhibited significantly higher δ13C values in the highly productive inshore sites and the δ13C values decreased seawards, implying a higher intrusion of atmospheric CO2 and lower photosynthetic fractionation due to algal blooming in the inner shelf. The δ13C values of fish also showed significant positive correlations with the concentration of surface chlorophyll a and nitrogen. Riverborne nutrients closely linked marine benthic consumers to the terrestrial watershed and tightly coupled the pelagic and benthic ecosystems in the ECS. The stable isotope compositions of benthic consumers can act as an indicator for pelagic trophic status. The future research combining analyses of stable isotope and community structure may improve assessment on the balance between contribution and risk of phytoplankton blooms. [ABSTRACT FROM AUTHOR]

A three dimensional coupled biophysical model was used to examine the supply of oceanic nutrients to the shelf of the East China Sea (ECS) and its role in primary production over the shelf. The model consisted of two modules: the hydrodynamic module was based on a nested model with a horizontal resolution of 1/18 degree, whereas the biological module was a low trophic level ecosystem model including two types of phytoplankton, three elements of nutrients, and biogenic organic material. Model results suggested that seasonal variation in chlorophyll-a had a strong regional dependence over the shelf of the ECS. The area with high chlorophyll-a appears firstly at the outer shelf in winter, and gradually migrates toward the inner shelf (offshore region of Changjiang estuary) from spring to summer. Vertically, chlorophyll-a was generally homogenous from the coastal zone to the inner shelf. In the middle and outer shelves, high chlorophyll-a appeared in the surface in spring but moved to the subsurface from summer to early autumn. The annual averaged onshore flux across the shelf break was estimated to be 1.53 Sv for volume, 9.4 kmol s-1 for DIN, 0.7 kmol s-1 for DIP, and 18.2 kmol s-1 for silicate, which are supplied mainly from the northeast of Taiwan and southwest of Kyushu. From calculations that artificially increased the concentration of nutrients in the Kuroshio water, the additional oceanic nutrients were distributed in the bottom layer from the shelf break to the region offshore of Changjiang estuary from spring to summer, and appeared in the surface layer from autumn to winter. The contribution of oceanic nutrients to primary production over the shelf was found not only in the surface layer (mainly at the outer shelf and shelf break in winter and in the region offshore of Changjiang estuary in summer) but also in the subsurface layer over the shelf from spring to autumn. [ABSTRACT FROM AUTHOR]

To investigate the influence of fresh water on phytoplankton absorption properties, the phytoplankton absorption coefficient and pigments identified by high-performance liquid chromatography (HPLC) were measured at the surface and subsurface chlorophyll a maximum (SCM) in the East China Sea (ECS), which is highly influenced by river discharge from the Changjiang during summer. For comparison, data were also collected in the Tsushima Strait (TS) at the surface and SCM. The majority of ECS surface samples taken from the low-salinity Changjiang diluted water (CDW), and even most of SCM samples taken from waters beneath the CDW, displayed significant freshwater influences. The specific absorption coefficient normalized by total chlorophyll a concentration (Tchl a), aph*(λ), of these samples was substantially higher than values derived from global regressions between aph*(λ) and the Tchl a. Using the pigment data derived from HPLC, the increase of aph*(λ) was found to be mainly caused by the phytoplankton size structure, which indicated that both surface and SCM samples in the ECS still incorporated considerable portions of picophytoplankton (cyanobacteria), even though the Tchl a was high. When water from the surface and the SCM were merged, variations in the phytoplankton size-fractions and aph*λ) vs. Tchl a that were consistent with values for the global ocean were found in the TS but not in the ECS. Data for the ECS indicated that there was no correlation between Tchl a and the size-fraction or total pigment absorption. As a consequence, aph*(λ) was poorly correlated with Tchl a and displayed large variability within a small Tchl a range. These findings suggest the need for care when considering the changing patterns of size-fractions vs. Tchl a and the relationship between aph*(λ) and Tchl a in coastal regions that are significantly influenced by fresh water. [ABSTRACT FROM AUTHOR]

This study reports thus far a most comprehensive dataset of surface seawater pCO2 (partial pressure of CO2) and the associated air-sea CO2 fluxes in a major ocean margin, the East China Sea (ECS) based on 24 surveys conducted in 2006 to 2011. We showed highly dynamic spatial variability of sea surface pCO2 in the ECS except in winter when it ranged in a narrow band of 330 to 360 µatm. In this context, we categorized the ECS into five different domains featured with different physics and biogeochemistry to better characterize the seasonality of the pCO2 dynamics and to better constrain the CO2 flux. The five domains are (I) the outer Changjiang estuary and Changjiang plume, (II) the Zhejiang-Fujian coast, (III) the northern ECS shelf, (IV) the middle ECS shelf, and (V) the southern ECS shelf. In spring and summer, pCO2 off the Changjiang estuary was as low as < 100 µatm, while it was up to > 400 µatm in fall. pCO2 along the Zhejiang-Fujian coast was low in spring, summer and winter (300 to 350 patm) but was relatively high in fall (> 350 patm). In the northern ECS shelf, pCO2 in summer and fall was > 340 patm in most areas, higher than in winter and spring. In the middle and southern ECS shelf, pCO2 in summer ranged from 380 to 400 µatm, which was higher than in other seasons (< 350 µatm). The area-weighted CO2 flux in the entire ECS shelf was -10.0 ± 2.0 mmol m-2 d-1 in winter, -11.7 ± 3.6 mmol m-2 d-1 in spring, -3.5 ± 4.6 mmol m-2 d-1 in summer and -2.3 ± 3.1 mmol m-2 d-1 in fall. It is important to note that the standard deviations in these flux ranges mostly reflect the spatial variation of pCO2, which differ from the spatial variance nor the bulk uncertainty. Nevertheless, on an annual basis, the average CO2 influx into the entire ECS shelf was -6.9 ± 4.0 mmol m-2 d-1, about twice the global average in ocean margins. [ABSTRACT FROM AUTHOR]

Severe tropical storms play an important role in triggering phytoplankton blooms, but the extent to which such storms influence carbon flux from the euphotic zone is unclear. In 2008, typhoon Fengwong provided a unique opportunity to study the in situ biological responses including phytoplankton blooms and particulate organic carbon fluxes associated with a severe storm in the southern East China Sea (SECS). After passage of the typhoon, the sea surface temperature (SST) in the SECS was markedly cooler (∼25 to 26 °C) than before typhoon passage (∼28 to 29 °C). The POC flux 5 days after passage of the typhoon was 265±14 mg-Cm-2 d-1, which was ∼1.7-fold that (140-180mg-Cm-2 d-1) recorded during a period (June-August, 2007) when no typhoons occurred. A somewhat smaller but nevertheless significant increase in POC flux (224-265 mg-Cm-2 d-1) was detected following typhoon Sinlaku which occurred approximately 1 month after typhoon Fengwong, indicating that typhoon events can increase biogenic carbon flux efficiency in the SECS. Remarkably, phytoplankton uptake accounted for only about 5% of the nitrate injected into the euphotic zone by typhoon Fengwong and it is likely that phytoplankton population growth was presumably constrained by a combination of light limitation and grazing pressure. Modeled estimates of new/export production were remarkably consistent with the average of new and export production following typhoon Fengwong. The same model suggested that during non-typhoon conditions approximately half of the export of organic carbon occurs via convective mixing of dissolved organic carbon, a conclusion consistent with earlier work at comparable latitudes in the open ocean. [ABSTRACT FROM AUTHOR]

The Kuroshio intrusion has a profound influence on the marine dynamic and ecological environment in the East China Sea (ECS) shelf. In most previous studies, the intrusion has been evaluated by the volume transport across the 200 m isobath. However, this approximate substitution leads to an underestimation of the Kuroshio intruding flux as it fails to separate the onshore and offshore transport of Kuroshio and shelf water. In this paper, a whole‐region passive‐tracing modeling method is proposed to quantitatively explore the bidirectional exchange of Kuroshio and shelf water, by introducing the Kuroshio water concentration as a passive tracer into the flux calculations. In terms of the climatological annual mean, the Kuroshio intrusion onto the ECS shelf is as high as 1.85 Sv (1 Sv = 106 m³ s−1), with a shelf water outflow rate of 0.42 Sv. The real Kuroshio intruding flux is about 30% higher than the net volume transport across the 200 m isobath (1.43 Sv), which indicates that the influence of the Kuroshio intrusion on the ECS may be far greater than believed before. The volume exchange on the inner shelf of the ECS is also discussed. Analyses of the momentum balances indicate that the exchanges on both the shelf break and the inner shelf are generally dominated by the geostrophic balance, but the exchange on the shelf break is more susceptible to nonlinear effects. The results of a set of sensitivity experiments show that variation of the Kuroshio intrusion is mainly regulated by the combined effect of the Kuroshio transport, the Taiwan Strait current, and the local wind stress. In contrast, the local wind stress has a predominant effect on the outflow of shelf water. Plain Language Summary: In this paper, the intruding flux of the Kuroshio water onto the East China Sea shelf is separated from the total cross‐shelf break transport and calculated with a whole‐region passive‐tracing method, revealing a quantity that is approximately 31% higher than those of the traditional net cross‐shelf break transport methods. The results of sensitivity experiments show that the variation of the Kuroshio intrusion is mainly regulated by the combined effect of the Kuroshio transport, the Taiwan Strait current, and the local wind stress. In contrast, the local wind stress has a predominant effect on the outflow of shelf water. [ABSTRACT FROM AUTHOR]

The giant jellyfish Nemopilema nomurai is the largest and most dangerous jellyfish species in East Asian waters, and the N. nomurai bloom causes serious problem in coastal industries, fisheries, and tourism. In the previous surveys, we found N. nomurai could not be observed in the south of 30°N. In this paper, we analyzed the mechanism of this phenomenon. After exploring the possible impacts of different environmental factors, we found that physical processes are essential to the distribution pattern of N. nomurai rather than biological or chemical factors in the East China Sea. The combination of the location of the initial breeding places of N. nomurai and the current system determine the distribution pattern. This study could provide important insights to the potential control of the giant jellyfish in the Chinese coastal waters. [ABSTRACT FROM AUTHOR]

In the Libya/Malta case, the ICJ held that where the area to be delimited between two opposite States measures less than 400 nautical miles, distance, not natural prolongation determines title to the continental shelf. This was the Court's interpretation of the definition of the continental shelf in Article 76(1) of the Law of the Sea Convention and of the relationship between the continental shelf and the exclusive economic zone. In the East China Sea which measures less than 400 nautical miles, China relies on natural prolongation while Japan relies on the distance principle. This paper analyses the Libya/Malta decision to ascertain its correctness or otherwise, and its usefulness for resolving the East China Sea dispute. The central argument in this paper is that the decision is inapplicable to the East China Sea dispute because it is incompatible with Articles 76(1), 77(3) and 56(3) of the Law of the Sea Convention. [ABSTRACT FROM AUTHOR]

In this paper, the microstructure images and parameters of the cohesive soil were obtained via scanning electron microscope testing technology and computer image processing technology. The physical-mechanical indexes of cohesive soil was obtained through geotechnical testing. The macro physical-mechanical indexes and microstructure parameters of cohesive soil in the inner shelf of the East China Sea were analysed by the regression analysis method; and the multiple regression equations between water content, liquid limit, compressibility coefficient, vane shear strength, micro-penetration resistance, medium diameter and the microstructure parameters were established. The results show that cohesive soils in the inner shelf of the East China Sea have three types of microstructure: Granular link-bond structure, flocculent link-bond structure and clay particle matrix structure. The physical indexes of cohesive soil mainly related to the microstructure parameters characterizing the size and number of pores, while the mechanical indexes, besides the size and number, also affected by the geometry of pores. Usually, the rounder the pore is and the more complicated the profile curve of pore is, the higher is the strength of cohesive soil. The results can provide theoretical reference for in-depth understanding the engineering properties of cohesive soil in the inner shelf of the East China Sea. [ABSTRACT FROM AUTHOR]

The continental shelf pump is believed to be important in transporting terrestrial materials across the East China Sea (ECS). More than 300 water samples collected from the ECS and a numerical model were used to identify the cross‐shelf exchanges of dissolved aluminum (Al) in the ECS in summer. The results indicated that dissolved Al concentrations ranged from <1.0 to 242 nM, with the highest concentrations observed in the Zhe‐Min coastal waters, while the lowest concentrations were determined to be in Kuroshio deep waters. The Kuroshio surface waters receive additional dissolved Al from the ECS continental shelf through a cross‐shelf exchange process. By using dissolved Al as a tracer, evidence was found about the cross‐shelf transport of Al in the ECS. Cross‐shelf transport of dissolved Al was associated with fluctuations in the Taiwan Strait Warm Water, and the driving mechanisms were analyzed using a momentum equation. Ekman transport promoted by the summer monsoon was the key physical mechanism controlling the off‐shelf transport of dissolved Al. Quantitative calculations showed that the ECS was a net source of dissolved Al to adjacent waters, of which almost 65% of the output entered the East/Japan Sea, while the remaining 35% entered the Kuroshio currents. Our results highlight the importance of cross‐shelf transport processes to the distribution and cycling of biogenic elements within the marginal seas of China, and highlight the wider implications for biogeochemical cycles throughout the western Pacific Ocean. Plain Language Summary: In this paper, we combined field observations with numerical models to study the transport of Al‐rich coastal waters to the adjacent oligotrophic offshore waters across the ECS continental shelf during summer 2013. Evidence was found about the cross‐shelf transport behavior of dissolved Al within the ECS, and the physical mechanisms controlling the off‐shelf transport of dissolved Al across the ECS continental shelf were investigated. The results indicated that the larger cross‐shelf transport was mainly driven by the summer monsoon. The primary objective of this study was to determine the forces driving off‐shelf transport of dissolved Al from the ECS continental shelf. Calculation of the exchange fluxes of dissolved Al along the 100 and 200 m isobaths indicated that the ECS continental shelf was a net source of dissolved Al to adjacent waters. Our results show the importance of cross‐shelf transport processes in the distribution and cycling of biogenic elements within the marginal seas of China, and highlight the potential wider implications for biogeochemical cycles throughout the western Pacific Ocean. Key Points: Combined field observations and numerical simulations were used to investigate the behavior of dissolved aluminum in the East China Sea (ECS)Knowledge of processes and physical mechanisms underlying off‐shelf transport of dissolved aluminum in the ECS was acquiredQuantitative study the off‐shelf and on‐shelf exchange fluxes of dissolved aluminum across the isobaths in the ECS [ABSTRACT FROM AUTHOR]

In this paper, we compared the normalized radar cross section in the cases of oil spill, biogenic slicks, and clean sea areas with image samples made from 11-pixel NRCS average, and determined their thresholds of the NRCS of the synthetic aperture radar. The results show that the thresholds of oil and biogenic slicks exhibit good consistency with the corresponding synthetic aperture radar images. In addition, we used the normalized radar cross section of clean water from adjacent patches of oil or biogenic slicks areas to replace that of oil or biogenic slicks areas, and retrieve wind field by CMOD5.n and compare wind velocity mending of oil and biogenic slicks areas with Weather Research and Forecasting modeled data, from which the root mean squares of wind speed (wind direction) inversion are 0.89 m/s (20.26°) and 0.88 m/s (7.07°), respectively. Therefore, after the occurrence of oil spill or biogenic slicks, the real wind field could be repaired using the method we introduced in this paper. We believe that this method could improve the accuracy in assessment of a real wind field on medium and small scales at sea, and enhance effectively the monitoring works on similar oil or biogenic slicks incidents at sea surface. [ABSTRACT FROM AUTHOR]

The East China Sea Shelf Basin (ECSSB) lies at the south‐eastern margin of the Eurasian Plate and was affected by the subduction of the Pacific Plate and the Philippine Plate. It experienced and recorded multistage tectonic inversions in the Cenozoic, especially in the Xihu Sag. In an attempt to investigate the evolution and mechanism of tectonic inversion, this paper presents numerical simulation results by the finite element method to the Xihu Sag. Combined with comprehensive structural analyses of seismic profiles, this paper determines the structural geometry of the sag for establishing a viscoelastic geologic model including six‐layer strata and nine major faults. Simulation results show that the boundary conditions of transtension and transpression control the inversion process that propagates from east to west, and the distribution of low compressive stress displays certain correlations with the distribution of oil deposits. Based on quantitative analysis of the vertical displacement field of the Xihu Sag, this paper identifies a tectonic inversion process, which indicates that the western part of the sag uplifts and the eastern part subsides during the first‐stage inversion; whereas the western part subsides and central‐eastern parts uplift during the second and third stages. The formation of the tectonic inversion is controlled by the adjustment of the stress field from dextral transtension to sinistral transpression caused by the change of subduction rates and direction of the Pacific Plate and the Philippine Sea Plate. [ABSTRACT FROM AUTHOR]

The genesis of the fine crystalline dolomites that exhibit good to excellent reservoir properties in the upper fourth member of the Eocene Shahejie Formation (Es) around the Sikou Sag, Bohai Bay Basin, is uncertain. This paper investigates the formation mechanisms of this fine crystalline dolomite using XRD, SEM, thin section analysis and geochemical data. The stratigraphy of the Sikou lacustrine carbonate is dominated by the repetition of metre-scale, high-frequency deposition cycles, and the amount of dolomite within a cycle increases upward from the cycle bottom. These dolomite crystals are 2-30 μm in length, subhedral to anhedral in shape and typically replace both grains and matrix. They also occur as rim cement and have thin lamellae within ooid cortices. Textural relations indicate that the dolomite predates equant sparry calcite cement and coarse calcite cement. The Sr concentrations of dolomites range from 900 to 1200 ppm. Dolomite δO values (−11.3 to −8.2 ‰ PDB) are depleted relative to calcite mudstone (−8.3 to −5.4 ‰ PDB) that precipitated from lake water, while δC values (0.06-1.74 ‰ PDB) are within the normal range of calcite mudstone values (−2.13 to 1.99 ‰ PDB). High Sr/Sr values (0.710210-0.710844) indicate that amounts of Ca and Mg have been derived from the chemical weathering of Palaeozoic carbonate bedrocks. The high strontium concentration indicates that hypersaline conditions were maintained during the formation of the dolomites and that the dolomites were formed by the replacement of precursor calcite or by direct precipitation. [ABSTRACT FROM AUTHOR]

Future international relations in East Asia are likely to be largely shaped by the maritime strategies and policies of various actors. This paper examines China's policy and behavior in maritime cooperation in the East Asian region in recent years, a topic that has been insufficiently understood. I suggest that while it is necessary and useful to take into account China's naval power, more attention to Chinese intentions and policy on East Asian maritime issues is warranted to arrive at a more balanced, and arguably more accurate, understanding of China's role in East Asian maritime affairs. This paper takes stock of China's changing perceptions, attitudes, and behaviors in maritime cooperation in the region. I describe China's new policy moves in the South China Sea and East China Sea. I also address some of the major Chinese concerns for further maritime cooperation in East Asia. I conclude that while a grand cooperative maritime regime is still not possible from a Chinese perspective, China is likely to agree to more extensive and substantive maritime cooperation in many functional areas, most notably in the non-traditional security arena. [ABSTRACT FROM AUTHOR]

The Asian Seas International Acoustics Experiment (ASIAEX) included two major field programs, one in the South China Sea (SCS) and the other in the East China Sea (ECS). This paper summarizes results from the work conducted during April and May 2000 and 2001 over the continental shelf and slope in the northeastern South China Sea, just east of Dongsha Island (Pratis Reef). The primary emphasis of the field program was on water-column variability and its impact on acoustic propagation loss. The reader is steered to the appropriate paper within this Special Issue when more information on a specific topic is desired. [ABSTRACT FROM AUTHOR]

Optimal array-processing techniques in the ocean often require knowledge of the spatial coherence of the reverberation. In this paper, a mathematical model is derived for the reverberation vertical coherence (RVC) in shallow water (SW). A method for analysis of RVC data is introduced. Measured reverberation cross-correlation coefficients as a function of time and frequency, obtained during the Asian Seas International Acoustic Experiment (ASIAEX) in the East China Sea, are reported. SW reverberation from a single shot provides a continuous spatial sampling of the surrounding sound field up to several tens of kilometers and holds valuable information on the geoacoustic properties of the sea floor over this distance. SW reverberation data can, therefore, be used as the basis for a quick and inexpensive method for geoacoustic inversion and has the obvious advantage that acquiring the data in situ requires only a single platform. This paper considers the use of the vertical coherence of the reverberation as the starting point for such an inversion. Sound speed and attenuation in the sea bottom at the ASIAEX site are obtained over a frequency range of 100-1500 Hz by finding values that provide the best match between the measured and predicted RVC. [ABSTRACT FROM AUTHOR]

This review paper provides a brief review on the development of ideas in the fields of the sea level change of the ECS (East China Sea), the history of the Yangtze River entering the sea and paleochannels in the shelf of the ECS since the Last Glacial Maximum (LGM). The paper summarizes two opposite theories about the Yangtze River entering the sea during the LGM. One theory is that the Yangtze River input a lacustrine in the north of Jiangsu province which was defunct in middle Holocene, and the river was once dry. The other was that the Yangtze River still existed and entered into the Okinawa Trough during the LGM, but scholars share different opinions on which course the river ran across and which place the river input the trough. This paper concludes future work is to study the evolution of the Yangtze River and the paleoclimate and the corresponding events as a whole from the view of regional and even global change, and more attention should be paid to the study on mud sediment, the Yangtze River's response to the changes in climate and sea-level, and the channel metamorphosis. [ABSTRACT FROM AUTHOR]

The East China Sea Shelf Basin (ECSSB) is a typical Meso-Cenozoic superimposed basin characterized by different tectonic frameworks, suffering multi-stage tectonism (e.g. the Indosinian, the Yanshanian and the Himalayan) since the Mesozoic. The Mesozoic ECSSB is a key place to our understanding of the tectonic evolution and dynamic mechanism in eastern South China and the subduction of the Izanagi Plate. Based on geological and geophysical results acquired over the last 10 years, this paper provides a summary of the distribution of Mesozoic strata, ascertains boundaries of the Mesozoic basin and proposes the division of the Mesozoic tectonic units in the ECSSB. The Mesozoic ECSSB was subdivided into the Western Fault Depression (WFD) characterized by dispersed Cretaceous half-grabens and the East Depression (ED) characterized by depressions at the early stage and grabens at the later stage. The WFD is composed of half-grabens formed under transtension, and the ED is composed of depression zones on the pre-Mesozoic basement under regional compression, indicating different dynamic mechanisms from the Cenozoic basins. Formation of the Mesozoic tectonic framework was controlled by the collision, compression and subduction of the Izanagi Plate and the Pacific Plate and also affected by the Indian Plate at a later stage. By comparison, this paper preliminarily proposes that the northern South China Sea and the ED of the ECSSB were originally a unified basin and jointly constituted a huge Mesozoic proto-basin in the East Asian continental margin. The Mesozoic tectonic unit division is helpful not only to discuss and resolve problems of ocean-continent differences and boundaries in southeastern South China but also to understand the tectonic nature of the East Asian continental margin, the dynamic mechanism of the Mesozoic basins and the transition of continental margin types. It also provides scientific support for petroleum exploration of the Mesozoic strata in the East China Sea. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The oil-gas accumulation process is a tectonic indicator, and the oil-gas trap is generally a result of tectonic movement. In order to explore the law of oil-gas migration and accumulation in the East China Sea Continental Shelf Basin, this paper analyses the dynamic process of hydrocarbon accumulation based on a geological model, taking the Xihu Depression as an example and using the IES PetroMod basin modelling software. Combined with the seismic data and drilling data, the burial history, thermal evolution history and hydrocarbon generation, expulsion and migration history of the Xihu Depression is simulated in this study. The simulation results show that (1) the tectonic framework of the Xihu Depression developed as an inversion structure from an early extensional stage or transtensional faulting stage to a later compressional or transpressional inversion stage; (2) the Pinghu and Huagang formations of the Xihu Depression are still currently at the peak stage of oil-gas generation, and the Xihu Depression is a depression which has abundant hydrocarbon generation and expulsion at a later stage; (3) oil-gas resources vertically migrated to the structural highs from the eastern and western sub-sags along faults and ultimately accumulated in favourable traps, which developed a migration pattern of interbedded sandstone-fault-sandstone like an upward 'staircase'. In particular, faults and the potential energy state played an important role in hydrocarbon migration of the Xihu Depression, which has a guiding significance for understanding hydrocarbon migration and accumulation law and reducing the risk in oil-gas exploration in the East China Sea Continental Shelf Basin. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The tectonic evolution of the ECSSB is well-regulated in three stages geologically. • The ECSSB tectonically migrated eastward in response to the westward subduction of the Pacific Plate. • 75 mm/a is a key value of the Pacific Plate subduction to the ECSSB evolution. Abstract The East China Sea Shelf Basin is one of the Mesozoic-Cenozoic basins located in the edge of eastern China continent whose formation and evolution are closely related to the subduction of the Pacific Plate. However, the underlying correlations between the tectonic evolution of the East China Sea Shelf Basin and the Pacific Plate subduction (65 Ma to present) remain poorly understood. In this paper, the basin is divided into western and eastern depression groups to further study its tectonic evolution. In combination with the characteristics of Pacific Plate subduction, this paper performs a coupling analysis of the basin evolution regarding its migration direction and evolution rate. The results of balanced section and deformation rate analyses reveal that the East China Sea Shelf Basin experienced different regional activities during the Cenozoic, which could be summarized as four geologic periods and three tectonic evolution stages. In this interpretation, it is recognized that tectonic activity occurred in the western depression group and then shifted to depocenters of the eastern group. In contrast, the Pacific Plate subducted westwards beneath the Eurasian Plate over the same geologic time span. Surprisingly, a slightly negative correlation between the intensity of the tectonic deformation of the East China Sea Shelf Basin and the subduction rate of the Pacific Plate is demonstrated when the subduction rate is no more than 75 mm/a. However, the basin deformation intensity increases with the plate subduction rate after 75 mm/a. The results of this work have implications for explaining the major role that the subduction of the Pacific Plate played in the formation and evolution of the eastern China basins. [ABSTRACT FROM AUTHOR]

Zhang, L.; Xu, J., and Peng, Y., 2015. Neotectonic movement and seismic activity in the East China Sea. The East China Sea region in this paper mainly includes the continental shelf of East China Sea and Okinawa trough. The geological structure in the region basically belongs to the extension part of China's east mainland to the sea area. In Cenozoic, this area developed the East China Sea shelf basin, Diaoyu uplift fold zone, and Okinawa trough basin. Since East China Sea is located in the bonded zone of continental plate and the Philippines Sea plate, the neotectonics and the geological structure generated since the Middle Miocene are unique and complex. Basing on fully interpreting the related data and research achievements of previous researchers, this study profoundly analyzed and studied the characteristics of the neotectonics in East China Sea region from a perspective of tectonic landform, geological structure, and seismic activity etc. On this basis, it further discussed the dynamic conditions and seismic activity characteristics of neotectonics in East China Sea area. [ABSTRACT FROM AUTHOR]

Abstract In recent years, providing green and reliable energy supply to islands has appeared in the strategic plans of many countries. This paper introduces three representative island microgrids that have been built and are operating in the East China Sea. Key technologies of the island microgrids are discussed, including the analysis of island resources and load, selection of energy storage, control strategies, and energy management systems. Through analyzing their operation data for one year, this paper demonstrates the impacts of the three microgrids from the perspectives of technology, economics, and sustainability. Summarizing the experiences and insights gained from their construction and operation, this paper provides references for the future development of island microgrid projects. Highlights • Three representative island microgrids in the East China Sea are demonstrated. • Key technologies such as control technology and energy management for island microgrids are studied. • Renewable energy penetration is discussed for the design and operation of island microgrids. • The operation data for a year of the three island microgrids are analyzed from various aspects. • Experiences and insights gained from the construction and operation are presented. [ABSTRACT FROM AUTHOR]

The current shear fronts (CSFs) in the East China Sea have been observed during winter in previous studies. In this research, we systematically study characteristics and variation mechanism of the CSFs and its potential effects on the transport of water and suspended sediment and on the inner shelf mud area (ISMA), using the methods of observation data analysis and numerical simulation. The spatial structures, shear intensities, and sea‐land locations of the CSFs are obviously affected by wind, temperature and salinity. The CSFs curve seaward due to the nonuniformity of topography, and the tide causes its periodic and sea‐land shift. The landward U component near the CSFs indicate little cross‐CSF transport (i.e., the barrier effect). The CSFs are important hydrodynamic factors that affect the formation of the ISMA. The periodic shift of the CSFs in the longitudinal direction and its variations in spatial structure are the main mechanisms affecting the spatial distribution and thickness of the ISMA. However, the barrier effect of the CSFs can be interrupted, and both the strong wind in the northeast direction and baroclinic conditions are beneficial for cross‐CSF transport. Furthermore, cross‐CSF transports occur in the upper layers under northwest wind condition, in areas with nonuniformity of topography and during the spring tide period. Three cross‐shelf channels are identified in areas where the CSFs curve seaward resulting from nonuniformity of topography. Plain Language Summary: Variation in the current shear front (CSF) and its potential effect on sediment transport over the inner shelf of the East China Sea (ECS) in winter were studied in this paper. Wind, temperature, and salinity affect CSFs in the ECS; topography induces its seaward curve; tide causes its periodic and sea‐land shift. The barrier effect of the CSFs affects the formation of the inner shelf mud area. But three cross‐shelf channels are identified during winter in areas where the CSFs curve seaward resulting from nonuniformity of topography. This study will provide reference for other sea areas where the CSFs have been found and corresponding suspended sediment transport process. Key Points: Wind, temperature, salinity, topography, and tide affect current shear fronts in the East China Sea during winterThe barrier effect of current shear fronts controls the spatial distribution and thickness of the inner shelf mud area in the East China SeaThree cross‐shelf channels are identified in areas where the current shear fronts curve seaward resulting from nonuniformity of topography [ABSTRACT FROM AUTHOR]

Much has been made over the past few years of China'vs ambitions of regaining control of its irredentist claims in the East and South China Seas. While some of this speculation focuses on the massive amounts of money the People's Republic of China (PRC) has funneled into its naval modernization program, other analysts are more interested in the drivers behind the increasingly popular sentiment that the country must “reclaim” its lost territories. The Chinese Communist Party can ill afford to ignore the voice of an already disenchanted population if it hopes to stay in power, particularly in regard to matters of national pride. As a result, in dealing with China's irredentist claims, nationalism in particular can be a powerful ideological factor in shaping the nation's foreign policies. This is especially apparent in the case of irredentism, where nationalism can often override diplomatic and strategic imperatives. This paper addresses the question of how does the nationalist discourse vary between two territorial disputes, the East and South China Seas. It uses discourse analysis to examine developing trends among online social media and news sites. This in turn allows for the construction of a framework of how nationalism develops among both elite and grassroots audiences. [ABSTRACT FROM PUBLISHER]

This paper briefly introduces the history of the study of the Pacific decadal oscillation (PDO) and explores the relationship between the PDO and sediment grain size from two typical sediment cores from the lower Changjiang (Yangtze River) and Huanghe (Yellow River) estuaries. It is found that the median grain sizes of both cores exhibit relatively high correlation with the PDO. This is because the PDO causes interdecadal variability of precipitation in the East Asia Monsoon region, thus changing the hydrodynamics in both the Changjiang and Huanghe catchments, eventually resulting in variation of sediment grain size. Our analysis also revealed that during different phases of the PDO, the sediment grain size of the Changjiang and Huanghe estuaries showed different variations in cold and warm PDO phases. This is related to movement of the precipitation center driven by the shift in different PDO phases. Moreover, we compared more high resolution geological proxies with the PDO, including stalagmites and tree rings, in East China over the past century. The results indicate that variations of studied geological proxies are generally well correlated with the PDO but have some differences. Finally, longer variations of sediment grain sizes in the Changjiang and Huanghe estuaries are compared with a reconstructed PDO over the last 200 years; sediment grain sizes were still correlated with the PDO, implying that sediment grain size may be used as a new proxy for studying the long-term behavior of the PDO. This result supports previous knowledge of the PDO impact on East China climate evolution and offers a new proxy for further PDO study. Our study will improve paleoenvironment reconstruction in East China on a decadal time scale and benefit future climatic predictions. [ABSTRACT FROM AUTHOR]

Based on the historical observed data and the modeling results, this paper investigated the seasonal variations in the Taiwan Warm Current Water (TWCW) using a cluster analysis method and examined the contributions of the Kuroshio onshore intrusion and the Taiwan Strait Warm Current (TSWC) to the TWCW on seasonal time scales. The TWCW has obviously seasonal variation in its horizontal distribution, T-S characteristics and volume. The volume of TWCW is maximum (13 746 km) in winter and minimum (11 397 km) in autumn. As to the contributions to the TWCW, the TSWC is greatest in summer and smallest in winter, while the Kuroshio onshore intrusion northeast of Taiwan Island is strongest in winter and weakest in summer. By comparison, the Kuroshio onshore intrusion make greater contributions to the Taiwan Warm Current Surface Water (TWCSW) than the TSWC for most of the year, except for in the summertime (from June to August), while the Kuroshio Subsurface Water (KSSW) dominate the Taiwan Warm Current Deep Water (TWCDW). The analysis results demonstrate that the local monsoon winds is the dominant factor controlling the seasonal variation in the TWCW volume via Ekman dynamics, while the surface heat flux can play a secondary role via the joint effect of baroclinicity and relief. [ABSTRACT FROM AUTHOR]

Chen, Y. P., Xie, D. M., Zhang, C. K, Qian, X. S., 2013. Estimation of long-term wave statistics in the East China Sea. This study used a state-of-the-art approach to estimate the long-term wave statistics in the East China Sea. The wave climate in the past 60 years (1950-2009) was simulated by a third generation wave model driven by the NCEP/NCAR reanalysis wind data. Based on the statistical analysis of the numerical results, the mean wave fields and the extreme wave fields with 100-year and 50-year return period on the whole computational domain were obtained. The spatial variations of the wave fields show that the statistical waves decrease from south to north and from sea to coast in general, which can be associated with the local topography of the East China Sea. The seasonal variations show that the mean waves in the winter and autumn are slightly larger than those in the spring and summer, while the extreme waves in the summer are much larger than those in the other seasons, which is mainly due to the seasonal variation of monsoonal winds and the occurrence of typhoon events in the summer. The outputs of this paper are helpful to understand the distribution of mean and extreme waves in the East China Sea, and also useful to calculate the design waves in the coastal area if nearshore wave model like the SWAN model is introduced. [ABSTRACT FROM AUTHOR]

Waves, winds and currents can be extracted from the Doppler power Spectra of HF Radar. Worldwide research has been done for this purpose during the last 4 decades. A new multi-frequency HF (MHF) radar is applied to enrich this study in a ten-day experiment completed in the East China Sea. The new MHF radar is designed to simultaneously work at four different frequencies at most between 7.5 MHz and 25 MHz. In this paper, we particularly focus on wave measurements, which were obtained both from MHF radar and wave buoy. A comparison of the two measurements is made, and the final result points out a potential and practical way to improve the performance of HF radar wave measuring. It is suggested that, when the fusion algorithm of multi-frequency data is robust enough, MHF radar can be widely used for ocean remote sensing. [ABSTRACT FROM AUTHOR]

Based on the Wentzel-Kramer-Brillouin modal condition, the phase shift of the bottom reflection coefficient can be extracted. The required input data for this inversion is the modal wavenumber. In this paper, the amount of phase shift of the bottom-reflection coefficient is estimated from the 2001 Asian Sea International Acoustic Experiment data in the East China Sea, in the frequency range of 100-200 Hz. Modal wavenumbers are estimated from using the cross-spectrum density matrix (CSDM) of reverberation data and a mode-shooting method. The error associated with the estimated phase shift is also discussed. [ABSTRACT FROM AUTHOR]

As part of the Asian Seas International Acoustics Experiment (ASIAEX), this paper describes the results of fine-scale characterization of surficial sediments at a site in the East China Sea using a conductivity probe. This probe is a modified version of a system originally developed for high-frequency acoustic backscatter applications [see Tang et al., "Fine-scale volume heterogeneity measurements in sand" IEEE J. Oceanic Eng., vol. 27, pp. 546-560, 2002, and Briggs et al., "Characterization of interface roughness of rippled sand off Fort Walton Beach, Florida," IEEE J. Oceanic Eng., vol. 27, pp. 505-514, 2002]. The new system has a single conductivity sensor that can move in both vertical and horizontal directions with controlled steps while taking data, thus resulting in a two-dimensional (2-D) grid on which medium conductivity is measured. Because sediment conductivity is much smaller than that of the overlaying seawater, bottom roughness is determined by selecting the grid points at which conductivity has a sudden drop along each vertical profile. Subbottom density variations are obtained by converting conductivity data to density using Archie's law and core density data. The spatial resolution of the measurements is designed to obtain environmental data suitable for modeling acoustic backscatter in the midfrequency (3-4 kHz) range. The results of this paper include the spectrum of sediment interface roughness and subbottom density gradient profiles. Error analysis is conducted to provide bounds on the results. It is found that bottom roughness is dominated by small features caused by bottom-dwelling organisms. A model is developed to simulate the random distributions of these bottom features. The model employs a superposition of discrete features, which results in a power spectrum that is consistent with the measured power spectrum. Potentially, this kind of model can provide a remote sensing means to estimate bottom biological populations through measuring... [ABSTRACT FROM AUTHOR]

Transform faults in back-arc basins are the key to revealing the opening and development of marginal seas. The Okinawa Trough (OT) represents an incipient and active back-arc or marginal sea basin oriented in a general NE-SW direction. To determine the strikes and spatial distribution of transform faults in the OT, this paper dissects the NW- and NNE-SN-trending fault patterns on the basis of seismic profiles, gravity anomalies and region geological data. There are three main NW-trending transpressional faults in the OT, which are the seaward propagation of NW-trending faults in the East China Continent. The NNE-SN-trending faults with right-stepping distribution behave as right-lateral shearing. The strike-slip pull-apart process or transtensional faulting triggered the back-arc rifting or extension, and these faults evolved into transform faults with the emergence of oceanic crust. Thus, the transform fault patterns are inherited from pre-existing oblique transtensional faults at the offsets between rifting segments. Therefore, the OT performs the oblique spreading mechanism similar to nascent oceans such as the Red Sea and Gulf of Aden. [ABSTRACT FROM AUTHOR]

The diversity and distribution of Hippodonta species on the coast of China are largely unknown due to limited investigations. In this paper, we report the detailed morphology and ultrastructure of two new species: H. nanjiensis sp. nov., collected from intertidal sandy sediments of Nanji Islands, the East China Sea and H. qingdaoensis sp. nov., collected from intertidal sandy sediments of the No. 1 Bathing Beach in Qingdao City, the Yellow Sea. Both species occur mainly in the middle part of the intertidal zone. H. nanjiensis possesses a unique large round central area. H. qingdaoensis differs from congeners in having a unique stria pattern, wherein the areolae in the middle transapical striae are less developed or absent on the primary side of the valve, and two areolae per stria are apparent under light microscopy (LM). This study expands our knowledge of Hippodonta diversity and distribution on the coast of China. [ABSTRACT FROM AUTHOR]

Carbon capture, utilization and storage (CCUS) technology is an important means to effectively reduce carbon emissions from fossil energy combustion and industrial processes. With the crisis of climate change, CCUS has attracted increasing attention in the world. CCUS technology as developed rapidly in China is technically feasible for large-scale application in various industries. The R&D and demonstration of CCUS in China Petroleum & Chemical Corporation (Sinopec) are summarized, including carbon capture, carbon transport, CO2 enhanced energy recovery (including oil, gas, and water, etc.), and comprehensive utilization of CO2. Based on the source-sink matching characteristics in China, two CCUS industrialization scenarios are proposed, namely, CO2-EOR, CO2-driven enhanced oil recovery using centralized carbon sinks in East China and CO2-EWR, CO2-driven enhanced water recovery (EWR) using centralized carbon sources from the coal chemical industry in West China. Finally, a CCUS industrialization path from Sinopec's perspective is suggested, using CO2-EOR as the major means and CO2-EWR, CO2-driven enhanced gas recovery (CO2-EGR) and other utilization methods as important supplementary means. [ABSTRACT FROM AUTHOR]