Phytoplankton in Prydz Bay and Its Adjacent Sea Area of Antarctica During the Austral Summer (1998/1999)

The cell density, species composition and distribution of phytoplankton, and their relations to environmental factors in Prydz Bay and its adjacent sea area, Antarctica (69degrees-77degrees E, 62degrees-70degrees S) during the austral summer of 1998/1999 were investigated. A total of 48 taxa belonging to 21 genera of phytoplankton in the sea area were identified. The average cell density of phytoplankton was 22.46 x 10(3) cells/dm(3), of which diatoms were predominant (84.51%). The highest cell density of phytoplankton occurred in Prydz Bay and the adjacent continental shelf where the average cell density was 46.03 x 10(3) cells/dm(3). The lowest cell density (3.34 x 10(3) cells/dm(3)) occurred in deep sea area. The dominant species of phytoplankton was Fragilariopsis curta. The vertical distribution of phytoplankton density was highest in the upper part of 0-50 in depth, lower in 100 in and lowest in 150 in. The species composition and cell density of phytoplankton were influenced by water circulation. The cell density was positively correlated with water temperature and salinity, and negatively correlated with the concentration of nutrients.

Research of the wave measurement using GPS absolute velocity estimation technology

This paper analyzed the existing methods of wave measurement, and described the advantages of GPS applied in measuring the wave. The equations of absolute velocity estimation were discussed, focusing on two methods with Doppler shill. The error sources and their effect on velocity estimation were analyzed. Then, some tests were carried on to simulate dynamic velocity determination using static data Based on the high-frequency carrier-phase derived Doppler observations, the velocity has been estimated to the precision of 1 cm/s or so, even to the mm/s level. And with the receiver generated Doppler measurements, the precision can reach 3 - 15 cm/s.

明年撤消登记甲基对硫磷的企业

20％高渗甲基对硫磷乳油 河南东方农化有限责任公司、河南海普农药工业有限公司、河南郑州化工试验所化工厂、河南郑州现代化工有限公司、山东潍坊汉邦农药有限公司。

Effects of UV-B radiation on fitness related behaviors of the sea urchin Strongylocentrotus intermedius

Ozone depletion induced by anthropogenic gases has been increasing the transmission of solar ultraviolet-B radiation(UV-B, 280–315 nm) through the atmosphere, which may impact the fitness of marine invertebrates in intertidal and shallow waters. To our knowledge, however, the responses of fitness related behaviors to UV-B radiation at different intensities have been rarely studied in marine invertebrates. For the first time, the present study investigated the eff ects of exposure of one hour to UV-B radiation at different intensities on foraging behavior, Aristotle's lantern reflex and righting behavior of the sea urchin Strongylocentrotus intermedius. Exposure of one hour to UV-B radiation at 10 μW/cm^2 significantly reduced foraging behavior. An intensity dependent eff ect of exposure to UV-B radiation was found in the duration of the Aristotle's lantern reflex. Exposure to UV-B radiation at 20 μW/cm^2 for one hour significantly reduced the duration of the Aristotle's lantern reflex, but 10 μW/cm^2 did not. There was no significant diff erence of righting response time among sea urchins exposed to 0, 10 and 20 μW/cm^2 for one hour. To test potential carryover ef fects, the behavioral traits were re-measured three days later. We found significant carryover eff ects of UV-B radiation on foraging time and righting response time, but not on the duration of the Aristotle's lantern reflex. The present study indicates that a brief exposure of one hour to UV-B radiation can significantly aff ect the duration of Aristotle's lantern reflex, righting response time and foraging behavior of a sea urchin, although the immediate impacts and carryover eff ects were highly trait dependent. This study provides new information into the behavioral responses of marine invertebrates to exposure to UV-B radiation. Future studies should be carried out to investigate long-term carryover eff ects of UV-B radiation on behavioral and physiological fitness related traits.

Reversal of monthly East Asian winter air temperature in 2020/21 and its predictability

In this study,the reversal of monthly East Asian winter air temperature(EAWT) in 2020/21 and its predictability were investigated.The reversal of monthly EAWT in 2020/21 was characterized by colder temperatures in early winter(December 2020 to mid-January 2021) and warmer temperatures in late winter(mid-January to February 2021).Results show that the reversal in the intensity of the Siberian high(SH) also occurred between early and late winter in 2020/21.In early winter,as the Barents-Laptev sea ice in the previous September(i.e., in2020) reached a minimum for the period 1981-2020,the SH was strengthaned via a reduction of the meridional gradient between the Arctic and East Asia.In late winter,as a sudden stratospheric warming occurred on 5 January 2021,the stratospheric polar vortex weakened,with the weakest center shifting to North America in January.Subsequently,the negative Arctic Oscillation-like structure shifted towards North America in the middle and lower troposphere,which weakened the SH in late winter.Furthermore,the predictability of the reversal in EAWT in 2020/21 was validated based on monthly and daily predictions from NCEP-CFSv2(National Centers for Environment Prediction-Climate Forecast System,version 2).The results showed that the model was unable to reproduce the monthly reversal of EAWT.However,it was able to forecast the reversal date(18 January 2021)of EAWT at lead times of 1-20 days on the daily scale.

Numerical simulation of the structure and variation of upwelling off the east coast of Hainan Island using QuikSCAT winds

The spatial structure and variation of the upwelling in the waters east and northeast of Hainan Island, China during 2000-2007 were investigated using a nested high-resolution Princeton Ocean Model (POM) forced by QuikSCAT winds. The model produced good simulations of the summer upwelling and the seasonal and annual variability. Strong upwelling occurs from mid-July to mid-August with a peak east of Hainan Island associated with the southwesterly monsoon in the South China Sea. Sensitivity experiments indicated that when the local wind stress controls the variability of the upwelling, the large-scale circulation significantly enhances the upwelling northeast of Hainan Island by inducing a local upwelling and transporting cold water northeast-ward along the island's east coast. The joint effects of the local wind stress and large-scale circulation result in stronger upwelling northeast of Hainan Island. This implies that the annual variation of the upwelling northeast of Hainan Island is controlled not only by the local alongshore wind stress but also by the large-scale circulation. This result will help us investigate the decadal variation of the upwelling in this region in the future.

Observed near-inertial waves in the wake of Typhoon Hagupit in the northern South China Sea

Energetic near-inertial internal waves （NlWs） were observed on the continental slope of the northern South China Sea in September 2008. Characteristics of the observed near-inertial waves were examined based on current data recorded by a moored acoustic Doppler current profiler. Results of a simple slab model indicated that the NIWs were generated by the surface winds of Typhoon Hagupit. Following Hagupit＇s passage, the wave field was dominated by baroclinic NIWs. The near-inertial currents were surface-intensified with a maximum of 0.52 m/s but still reached 0.1 m/s at the depth of 210 m. Moreover, the near-inertial currents were clockwise-polarized and slightly elliptical. A depth-leading phase of the near- inertial currents was evident, which indicated downward energy propagation. However, the rotary vertical wavenumber spectra suggested that upward energy propagation also existed, which was consistent previous theoretical study. The frequency of the NIWs, modified by the positive background vorticity, was 0.714 2 cycles per day, which was 0.02f0 higher than the local inertial frequency （f0）. The near-inertial kinetic energy evolved exponentially and had an e-folding timescale of about 3 days. The vertical phase and group velocity were estimated to be 10 and 2.1 m/h, respectively, corresponding to a vertical wavelength of 340 m. The NlWs were dominated by the second mode with a variance contribution of 〉50%, followed by the third mode, while the first mode was insignificant.

Methane seepages in the northern South China Sea: evidence from in situ measurements

Continental margins in world oceans contain large amounts of marine gas hydrates. Changes in the temperature and pressure of sediment may destabilize the methane hydrate, leading to its release and seepage into the sea. This process would increase the dissolved methane in the ambient seawater. In this study, a methane sensor was used to detect methane anomalies in the water column in southwestern Dongsha and Shenhu, northern slope of the South China Sea. Methane plumes were detected at stations SCS001 and T001 in the southwestern Dongsha area, and station SCS002 in the Shenhu area, respectively. The maximum methane concentrations were 8.8 nmol/L in southwestern Dongsha and 10.1 nmol/L in Shenhu, which are about 4–5 times higher than the background methane concentration. This indicates that there are active methane seepages present in both the southwestern Dongsha and Shenhu areas, which are likely related to a methane hydrate reservoir beneath the seafloor. A methane sensor with a low detection limit is a practical instrument with which to detect methane plumes in oceanic environments and to monitor methane leakage from the seafloor.

A numerical study on seasonal variations of the Taiwan Warm Current

Princeton Ocean Model (POM) is employed to investigate the Taiwan Warm Current (TWC) and its seasonal variations. Results show that the TWC exhibits pronounced seasonal variations in its sources,strength and flow patterns. In summer, the TWC flows northeast in straight way and reaches around 32°N; it comes mainly from the Taiwan Strait, while its lower part is from the shelf-intrusion of the Kuroshio subsurface water (KSSW). In winter, coming mainly from the shelf-intrusion of the Kuroshio northeast of Taiwan, the TWC flows northward in a winding way and reaches up around 30°N. The Kuroshio intrusion also has distinct seasonal patterns. The shelf-intrusion of KSSW by upwelling is almost the same in four seasons with a little difference in strength; it is a persistent source of the TWC. However, Kuroshio surface water (KSW) can not intrude onto the shelf in summer, while in winter the intrusion of KSW always occurs. Additional experiments were conducted to examine effects of winds and transport through the Taiwan Strait on the TWC. In winter, northerly winds enhance the shelf-intrusion of the Kuroshio and spread northward, but hamper the northward inflow from the Taiwan Strait. In summer, the effect of the winds is confined in the surface layer, and less obvious than that of winter. Transport through the Taiwan Strait influences the TWC significantly. With the Taiwan Strait closed in the simulation, the TWC would be dramatically weakened.

Observations and Simulations of the Circulation and Mixing around the Andaman-Nicobar Submarine Ridge

Using data collected by an Acoustic Doppler Current Profiler （ADCP） on a research cruise in April 2010 in the eastern Indian Ocean, the vertical cun＇ent structures surrounding the Andaman-Nicobar Submarine Ridge （ANSR） are analyzed to investigate the hydrographic responses to the topography in this region. The results show that the topography of ANSR can induce internal waves around the submarine ridge that have a maximum current velocity of 1 m s 1 The spatial struc- ture of the turbulent kinetic energy （TKE） and shear in this region during 2010 is investigated using the high-resolution Princeton Ocean Model （POM） forced by the satellite-based Advanced Scatterometer （ASCAT） winds including the tide, The results show that the model successfully simulates the internal waves around the ANSR. Numerical experiments further indicate that both the topography and tide play an important role in the gen- eration of the internal waves in this region.

Analysis of Equatorial Currents Observed by Eastern Indian Ocean Cruises in 2010 and 2011

Hydrographic and direct current measurements were made in the Eastern Equatorial Indian Ocean in May 2010 and April 2011 as part of the Eastern Indian Ocean Cruises(EIOC) organized by the South China Sea Institute of Oceanology(SCSIO).Analyses of the shipdrift Acoustic Doppler Current Profiler(ADCP) data indicate that the equatorial currents observed in May 2010 are characterized by a strongly eastward surface current(Wyrtki Jets,WJs) with a maximum velocity of 0.9 m s 1,while that observed in April 2011 is weak and without a consistent direction.The strongly eastward WJ transports the surface water eastward,resulting in a deeper upper mixed layer,as shown in the temperature and salinity profiles.However,it was found that the Equatorial Undercurrent(EUC) in the Eastern Indian Ocean is strong in April 2011 and weak in May 2010.The EUC was located approximately at the position of the thermocline,and it had higher salinity(up to approximately 35.5 psu) than the upper and lower waters.

Bridging Civilizations From Asia to Europe： The Silk Road

Throughout history, Silk Road played an important role with connecting more than 50 countries between its endpoints. Reviving this ancient trade route is a contemporary discussion among politicians. There are many projects realized and proposed for the resurgence of the modem Silk Road, including the railroad project connecting Baku, Tiflis and Kars of Azerbaijan, Georgia, and Turkey; the undersea rail tunnel under the Bosphorus strait, Marmaray; the Silk Road Economic Belt proposed by China; and the Maritime Silk Road, again proposed by China. Just like the original Silk Road, it was not only a route for caravans or trade, but it was a meeting point for cultural, religious, and philosophical exchanges that served humanity for centuries; today＇s modem Silk Road initiatives should be considered as bridges between Eastern and Western civilizations that will serve the same purpose of its ancient predecessor. The revived Silk Road will facilitate strengthening of relationships in between countries that experienced harmony in history. The railways, transportation facilities, transnational gates, energy corridors, and natural gas pipelines that constitute the Silk Road will transform the region with improving its economy and bringing peace and economic prosperity. With recent developments, it witnesses the importance of geopolitical and historical ties in establishing contemporary alliances. Although there are great expectations with the revival of the modern Silk Road, authors would like to emphasize that it should be an agreement to foster shared interests rather than the interest of bigger partners.

The upper-ocean response to typhoons as measured at a moored acoustic Doppler current profiler

A moored acoustic Doppler current profiler(ADCP) data,satellite-derived sea surface wind data,and the chlorophyll-a concentration were used to examine the influence of typhoon events on the upper ocean in the central Luzon Strait. The data were collected between August 27 and October 6,2011. Large changes in ocean dynamics and marine life were recorded in the upper layers over the short term during the transit of each of the three violent typhoons that passed over the region during the study period. The geostrophic flow during the period of ADCP monitoring was comparable to the Ekman flow,recently shown to be prominent in the upper layer. Based on the influence of the three typhoon events that swept the Luzon Strait or traversed Luzon Island on their way to the South China Sea,we postulated a typhoon-induced upwelling around the ADCP and found that upward isothermal displacements reached 11.8–39.0 m,which was confirmed by the sea-level anomaly data recorded at the same time. This variability in the upper ocean may play an important role in biological activity,especially in offshore deep-sea regions.

Scattering of Surface Waves by the Edge of a Small Undulation on a Porous Bed in an Ocean with Ice-cover

Scattering of surface waves by the edge of a small undulation on a porous bed in an ocean of finite depth, where the free surface has an ice-cover being modelled as an elastic plate of very small thickness, is investigated within the framework of linearized water wave theory. The effect of surface tension at the surface below the ice-cover is neglected. There exists only one wave number propagating at just below the ice-cover. A perturbation analysis is employed to solve the boundary value problem governed by Laplace＇s equation by a method based on Green＇s integral theorem with the introduction of appropriate Green＇s function and thereby evaluating the reflection and transmission coefficients approximately up to first order. A patch of sinusoidal ripples is considered as an example and the related coefficients are determined.

Degradation of lipids in seasonal hypoxic seawater under different oxygen saturation

The hypoxic phenomena of seawater have been found in the Changjiang esturay and its adjacent area for several decades. To study organic matter degradation in seasonal hypoxic seawater, series of stimulated incubation experiments with S keletonema costatum in seawater under different oxygen saturations were conducted. By tracking variations of lipids originated from the alga, time-dependent concentrations of neutral lipids(hexadecanol, otctadecanol, cholesterol, brassicasterol and phytol) and fatty acids(12:0, 14:0, 16:0, 16:1, 18:0, 18:1(9), 20:5 and 22:6) were obtained during three month of incubation. The results indicate that residence time, oxygen saturation, bacterial community and the structure of lipids were key factors controlling preservation and degradation of lipids in seawater. The degradation rate constants calculated from multi-G model showed that under same oxygen saturation, algal fatty acid degraded faster than neutral lipids, and unsaturated fatty acids degraded faster than saturated fatty acids. Our new discovery showed that degradation rate constant had linear positive correlation with oxygen saturation of seawater, indicating the critical role of oxygen on degradation of algal lipids in hypoxic seawater. The results of this study will be helpful to understand organic carbon cycling in seawater and marine environment more deeply. Future field experiments and investigation should be conducted tracking control factors, especially the role of oxygen saturation on organic matter degradation in natural environment.

Seasonal Suspended Particles Distribution Patterns in Western South Yellow Sea Based on Acoustic Doppler Current Profiler Observation

An Acoustic Doppler Current Profiler （ADCP） observation site was set up in the Western South Yellow Sea from 2012 to 2013 to study the local suspended particle matters （SPM） distribution pattern. The SPM concentration could be semi-quantitatively represented by backscatter intensity （Sv）, converted by the echo intensity （E/） of ADCP. Results show two types of SPM in the water column： the quasi-biological SPM and quasi-mineral SPM. The quasi-biological SPM mainly exists in summer half year and is con- centrated above the thermocline. It has periodically diurnal variations with high concentration at night and low concentration in the daytime. The quasi-mineral SPM is located in lower part of the water column, with similar relation to monthly tidal current variation all year round. However, the daily quasi-mineral SPM distribution patterns vary between summer and winter half year. The sunlight is thought to be the origin factor leading to the diurnally vertical motion of the biological features, which might cause the diurnal Sv variation. Unlike in winter half year when tidal current is relatively single driving force of the monthly SPM pattern, the high speed current near the thermocline is also responsible for the concentration of quasi-mineral SPM in summer half year. The sediment input difference between summer and winter half year contribute to the varied daily variation of quasi-mineral SPM with re-suspended SPM ir~ winter and sediments from Yellow Sea Mud Area （YSMA） in summer. The seasonal variations in hydrodynamics, water structure and heavy-wind incidents are the primary factors influencing the differential seasonal SPM distribution patterns.

Temporal variations in internal tide multimodal structure on the continental shelf, South China Sea

Temporal variations in multimodal structures of diurnal( D_1) and semidiurnal( D_2) internal tides were investigated on the continental slope of the Dongsha Plateau, based on 2-month moored acoustic Doppler current profiler observations. Harmonic analysis indicated that the D_1 components( K_1 and O_1) dominated the internal tide field. The vertical structure of the K_1 constituent presented a first-mode structure while the M_2 constituent seemed to exhibit a high-mode structure. Amplitude spectra analysis of the current data revealed differences in baroclinic current amplitudes between different water depths. Temporal variations in modal structures ware analyzed, based on the D_1 and D_2 baroclinic tides extracted from the baroclinic velocity field with band-pass filters. Analysis showed that the magnitude of the D_1 internal tide current was much larger than the D_2 current, and temporal variations in the modal structure of the D_1 internal tide occurred on an approximately fortnightly cycle. The EOF analyses revealed temporal transformation of multimodal structures for D_1 and D_2 internal tides. The enhancement of the D_1 internal tide was mainly due to the superposition of K_1 and O_1, according to the temporal variation of coherent kinetic energy.

Tide and Current Observations in the Central Chukchi Sea During the Summer of 2012

Current data from a moored Acoustic Doppler Current Profiler （ADCP） deployed at 69°30.155N, 169″00.654″W in the central Chukchi Sea during 2012 summertime is analyzed in the present paper. Characteristics of tidal and residual currents are obtained with Cosine-Lanczos filter and cross-spectral analyses. The main achievements are as follows： 1） Along with the local inertial frequency of 12.8 h, two other peaks at -12-h and -10-d dominate the time series of raw velocity; 2） The M2 dominates the 6 resolved tide constituents with significant amplitude variations over depth and the ratios of current speed of this constituent to that of the total tidal current are 54% and 47% for u and v components, respectively. All the resolved tidal constituents rotate clockwise at depth with the exception of MM and O1. The constituents of M2 and $2 with the largest major semi-axes are similar in eccentricity and orientation at deeper levels; 3） The maximum of residual currents varies in a range of 20-30 cm s-1 over depth and the current with lower velocities flow more true north with smaller magnitudes compared to the current in surface layer. The -10d fluctuation of residual current is found throughout the water column and attributed to the response of current to the local wind forcing, with an approximate 1.4 d lag-time at the surface level and occurring several hours later in the lower layer; 4） Mean residual currents flow toward the north with the magnitudes smaller than 7 cm s-1 in a general agreement with previous studies, which suggests a relatively weaker but stable northward flow indeed exists in the central Chukchi Sea.

Barotropic current fluctuations coupled with sea level drawdown in Yellow and Bohai Seas

Sub-tidal barotropic current variations coupled with residual sea level fluctuation in the Bohai and Yellow Seas during wintertime are addressed in this study.The temporal evolution and spatial distribution of current fluctuation are investigated using moored acoustic Doppler current profiler data in a three-dimensional numerical model.It is found that a southward current followed by a northward current occurred in the northern Yellow Sea during the fluctuation,concurrent with a significant outflow followed by inflow through the Bohai Strait.The process is consistent from surface to bottom and is coupled with remarkable residual sea level fluctuation.This quasi three-day fluctuation with amplitude 0.2-0.3 m/s leads to 1 m/1.2 m drawdown in the northern Yellow and Bohai Seas,respectively,strongly influencing water exchange between those seas.Because this a prominent feature in the seas,it is necessary to evaluate its effect on fluctuation during winter in future studies,in particular,the northward current during the recovery phase of sea level in the Bohai and Yellow Seas regarding seasonal variation.