Water quality and eutrophication in the Guangzhou Sea Zone of the Pearl River estuary

To gain a better understanding of water quality and eutrophication,we investigated the seasonal and spatial distribution of water quality at 17 stations in the Guangzhou Sea Zone (GZSZ).Nutrients,chlorophyll-a (Chl-a),salinity,chemical oxygen demand,and other physical and chemical parameters were determined in February,May,August and October from 2005 to 2007.The concentrations showed ranges of 93.2-530.4 μmol/L for dissolved inorganic nitrogen (DIN),0.62-3.16 μmol/L for phosphate (PO4-P) and 50-127 μmol/L ...     

The absorption of water color components and spectral modes in the Pearl River estuary

In-situ data from cruises in the Pearl River estuary and adjacent marine areas were collected during March to May 2001. The absorption coefficients of the water color components were studied in detail containing total suspended matter (TSM), chlorophyll-a (chl-a), colored dissolved organic matter (CDOM), and de-pigment particles. For absorption coefficient of TSM, ap, and that of de-pigment particles, ad, correlations of ap(440)-TSM, ad(440)-TSM, ap(440)-chl-a and ad-chl-a were done (the italicized term means the concentration). There was a good correlation between ap(440) and chl-a concentration. An empirical relationship model between aph(675) and chl-a was developed showing a strong correlation of 0.93. Based on the two models the chl-a and aph(λ) were correlated. The values of calculated empirical spectral slope for CDOM absorption coefficients and that of de-pigment particles, 0.017 0 and 0.011 6 respectively, both are within a relative standard error of 10.0%.     

Estimation of total suspended matter in the Zhujiang (Pearl) River estuary from Hyperion imagery

Although remote sensing data have been used to estimate total suspended matter (TSM) in coastal waters, it has limitations when applied to estuary waters in low spatial resolution situations. The spatial resolution of ocean color satellites such as SeaWiFS and MODIS is usually ～1 km, and therefore is not adequate for small, local-scale areas such as the Zhujiang (Pearl) River estuary. In contrast, 30 m-resolution EO-1 Hyperion imagery has potential for studying TSM in localized areas. We measured the surface spectral radiance reflectance of the river estuary water in the visible and near infra-red spectral range. Sensitivity analysis indicated that the ratio of remote sensing reflectance at 813 nm (Rrs(813)) to reflectance at 559 nm (Rrs(559)) could be used to estimate TSM concentration, and a linear relationship was established between the ratio and in-situ TSM concentration. We applied the linear relationship to Hyperion imagery to map TSM concentration in the estuary. The Hyperion imagery provided sufficient spatial resolution to detect spatiotemporal changes in TSM concentrations in the estuary small estuary area. This study demonstrated the usefulness of Hyperion imagery for mapping the distribution of TSM in estuary waters.     

广州珠江三角洲海水入侵地区地下水微粒的TEM分析及意义

广州地区地下水咸化现象由来已久,通过透射电子显微镜对广州珠江三角洲地下水的咸化原因进行了研究,并评价了其咸化程度。通过研究广州地区地下水中的微粒特征,包括观察微粒的形貌、结晶程度和化学成分等特征,同时对比现代海水微粒特征,讨论了微粒特征用于地下水咸化原因探究和评价的可行性。研究发现,在咸化程度不同的样品中,微粒中Cl含量不同,没有咸化的样品中难以找到Cl元素,咸化程度越高,微粒中Cl含量可以越高。同时,在受到海水入侵的地下水微粒中发现了具有海洋来源含Sr、Ba等微量元素的微粒,这些微量元素在一定程度上可视为海水的示踪剂,说明该组地下水受到了不同程度的海水浸染。通过透射电子显微镜分析研究了地下水中的微粒,结果表明,该研究区地下水中的微粒继承了海水中的微粒特征,广州市地下水的咸化是由于海水入侵所致,因此,利用微粒特征用于海水入侵的判别分析和评价是可行的。类似地,该方法同样可用于水污染调查以及地下水找矿研究。      

Relocation of the Yellow River estuary in 1855 AD recorded in the sediment core from the northern Yellow Sea

Relocation of the Yellow River estuary has significant impacts on not only terrestrial environment and human activities, but also sedimentary and ecological environments in coastal seas. The responses of regional geochemical characteristics to the relocation event, however, have not been well studied. In the present study, we performed detailed geochemical elemental analyses of a sediment core from the northern Yellow Sea and studied their geochemical responses to the 1855 AD relocation of the Yellow River estuary. The results show that TOC/TN, Co/Al₂O₃, Cr/Al₂O₃, Ni/Al₂O₃ and Se/Al₂O₃ ratios all decreased abruptly after 1855 AD, and similar decreases are observed in the sediments of the mud area southwest off the Cheju Island. These abrupt changes are very likely caused by the changes in source materials due to the relocation of the Yellow River estuary from the southern Yellow Sea to the Bohai Sea, which the corresponding decreasing trends caused by the changes in main source materials from those transported by the Liaohe River, the Haihe River and the Luanhe River to those by the Yellow River. Because the events have precise ages recorded in historical archives, these obvious changes in elemental geochemistry of sediments can be used to calibrate age models of related coastal sea sediments.     

Distribution of nutrients and eutrophication assessment in the Bohai Sea of China

Water samples were collected in 120 stations in the Bohai Sea of China to analyze the distribution of dissolved nutrients and assess the degree of eutrophication in August 2002. The result shows that the average concentration of DIN increased and the PO4-P concentration sharply decreased compared to the previous data of corresponding period. The high concentrations of DIN and PO4-P occurred in coastal waters, especially in the bays and some river estuaries, while the high concentrations of SiO3-Si in the surface and middle depth occurred in the central area of the Bohai Sea. The average ratio of DIN/ PO4-P was much higher than the Redfield Ratio (16:1). Apparently, PO4-P was one of the limiting nutrient for phytoplankton growing in the sea. The average concentrations of DON and DOP were higher than their inorganic forms. The results of eutrophication assessment show that 22.1% of all stations were classified as violating the concentration levels of the National Seawater Quality Standard (GB 3097-1997) for DIN and only 3.9% for PO4-P. The average eutrophication index in the overall area was 0.21±0.22 and the high values occurred in Bohai Bay, Liaodong Bay and near the Yellow River estuary. This means that the state of eutrophication was generally mesotrophic in the Bohai Sea, but relatively worse in the bays, especially some river estuaries.     

Potential submarine geologic hazards at the entrance of the Pearl River Estuary in the northern South China Sea

The potential submarine geologic hazards were distinguished and categorized at the entrance of the Pearl River Estuary in the northern South China Sea, based upon the analysis of side scan sonar and sub-bottom profiler surveying data of about 2500 km long, in an area about 2000 km~2 around the Wanshan Archipelago. The data obtained in the survey has the highest spatial resolution by far, which could reveal more detailed distributions and characteristics of the geologic hazards than before. In the study region, three paleo-channels that were buried about 10–30 m below the seabed were found; more than 10 shallow gas areas were discovered. The sand waves found in the region were generally small and located near the islands, and twenty pockmarks found on the seabed were mostly concentrated to north of Zhuzhou island. There are also many man-made obstacles in the region, such as wreckages, pipeline, etc. In this paper we provide a detailed distribution map of the submarine geologic hazards in this region for the first time, and discuss their formation and harmfulness, which will provide a scientific basis for marine engineering construction, marine geologic disaster prevention and mitigation.     

Fluvial process of the Huanghe River estuary

Influence of the evolution of the Huanghe River estuary, especially that of four large avulsions in recent years 1953, 1960, 1964 and 1976 on the lower reach was discussed. From this some measures for solving the problem of sedimentation at river mouth were proposed. This paper was published in Chinese inOceanologia et Limnologia Sinica 13 (3): 218–224, 1982. The main ideas of the first three parts of this article were included in the report delivered at the International Symposium on River Sedimentation held in Beijing, March 24–29, 1980.     

WATER RESOURCES TRANSFORMATION AND WATER QUALITY VARIATION IN THE URUMQI RIVER BASIN

ＷＡＴＥＲＲＥＳＯＵＲＣＥＳＴＲＡＮＳＦＯＲＭＡＴＩＯＮＡＮＤＷＡＴＥＲＱＵＡＬＩＴＹＶＡＲＩＡＴＩＯＮＩＮＴＨＥＵＲＵＭＱＩＲＩＶＥＲＢＡＳＩＮＱｕＹａｏｇｕａｎｇ（曲耀光）；ＬｕｏＨｏｎｇｚｈｅｎ（骆鸿珍）（ＬａｎｚｈｏｕＩｎｓｔｉｔｕｔｅｏｆＧ...     

Primary fish survey in the Huanghe River estuary

The survey in the Huanghe River estuary indicated that the 85 fish species found there comprised three faunal elements: warm-water species (29.4%), warm-temperate species (55.3%) and cold-temperate species (15.3%). The seasonal changes of fish species, density and biomass are obvious. The total biomass is highest (7 699t) in August and lowest (489 t) in January.Setipinna taty has mean density of 9 278 indiv/km², and is the most important species constituting 25.5% of the total weight of fish caught.Trichiurus haumela was a dominant species in the 1950s, but no one was caught in this survey. There were obvious changes of the dominant fish species during the recent three decades. The demersal fish biomass has dropped greatly to only 1/10 in over 50 years since 1930. Contribution No. 2210 from the Institute of Oceanology, Academia Sinica.     

SEDIMENT TRANSPORT IN YALU RIVER ESTUARY

Tidal cycle measurements of tidal currents, salinity and water temperature, and suspended sediment concentra-tions were measured at four stations, together with surveys along two profdes short core collection within the Yalu River estuary.Grain size analysis of the three core sed~ment showed that: 1 ) the sediment from B1 to B3 became finer, worse sorting andpositively skewed; 2) the diversification of matter origin became more and more evident from east to west; 3) the sedimenta overthe region were of the same origin, as indicated by their similar colors and grain sizes. The data indicated that stratification occurred in the flood season, from upstream to downstream, and a salt wedge was formed. The water column was well mixed, butthe longitudinal gradient of the salinity was larger on spring tide. The resulta also showed that the dominating mechanism ofsuspended sediment transport in the Yalu River estuary was T1, T2, T3 and T5. The non-tidal steady advection transport wasrestricted by the net transport of suspended sediment induced by mass Stoked drift directed to landwards, then the net sedimenttransport rate were decreased and the turbidity maxima was also favored to forming and extending.     

Nitrogen and phosphorus budgets of the Changjiang River estuary

Eutrophication has emerged as a key environmental problem in Chinese coastal waters, especially in the Changjiang (Yangtze) River estuary. In this area, large nutrient inputs result in frequent harmful algal blooms and serious hypoxia in bottom waters. Four cruises were made in the estuary in 2006 to assess the concentration and distribution of dissolved inorganic nitrogen (DIN) and phosphorus (DIP). The concentration of DIN decreased gradually in a linear relationship with salinity from the river mouth to ...     

Metabolic and phylogenetic profile of bacterial community in Guishan coastal water (Pearl River Estuary), South China Sea

Characteristics of a microbial community are important as they indicate the status of aquatic ecosystems. In the present study, the metabolic and phylogenetic profile of the bacterioplankton community in Guishan coastal water(Pearl River Estuary), South China Sea, at 12 sites(S1–S12) were explored by community-level physiological profiling(CLPP) with BIOLOG Eco-plate and denaturing gradient gel electrophoresis(DGGE). Our results showed that the core mariculture area(S6, S7 and S8) and the sites associating with human activity and sewage discharge(S11 and S12) had higher microbial metabolic capability and bacterial community diversity than others(S1–5, S9–10). Especially, the diversity index of S11 and S12 calculated from both CLPP and DGGE data(H 3.2) was higher than that of others as sewage discharge may increase water nitrogen and phosphorus nutrient. The bacterial community structure of S6, S8, S11 and S12 was greatly influenced by total phosphorous, salinity and total nitrogen. Based on DGGE fingerprinting, proteobacteria, especially γ- and α-proteobacteria, were found dominant at all sites. In conclusion, the aquaculture area and wharf had high microbial metabolic capability. The structure and composition of bacterial community were closely related to the level of phosphorus, salinity and nitrogen.     

Marine ciliate community in relation to eutrophication of coastal waters in the Yellow Sea

We assessed the potential of marine ciliate community as an indicator to coastal water quality using water samples collected from four stations in the Yellow Sea in the summer 2000. The four stations were characterized by different levels of pollution. The ciliate communities consisted primarily of tintinnids and aloricate ciliates that were <30 μm. A total of 78 species were classified: 55 species at Station 2, 51 species each at Stations 1 and 4, and 47 species at Station 3. The mean number of species at each site was 29.2±2.0 (Station 1), 28.5±2.9 (Station 2), 27.8±1.7 (Station 3), and 24.5±2.3 (Station 4). The abundance was highly variable: 19 331±11 187 ind./L at Station 1, 7 960±5 639 ind./L at Station 2, 29 015±12 999 ind./L at Station 3, and 8 190±4 658 ind./L at Station 4. Our results suggest that neither the simple chemical analysis (e.g. chemical oxygen demand, dissolved inorganic nitrogen, and phosphate) nor the eutrophication/pollution index adequately described the water quality at the four stations. The same was true of the number of species and their abundance, both of which had no correlation with the chemical indices. In contrast, Margalef’s diversity index values (3.12 at Station 2, 2.89 at Station 1, and 2.64 at Stations 3 and 4) generally discriminated the water quality status of the four stations. The difference in water quality among the stations was strongly supported by the pattern of species richness (i.e. the total number of species) of ciliates at each station. Our evaluation was consistent with the results of long-term water quality monitoring at the four stations. With increasing eutrophication, we observed also a compositional and functional shift in the ciliate assemblages from algivorous oligotrich/choreotrich to nonselective-omnivorous gymnostomatids to bacterivorous-detrivorous scuticociliatids. Thus, ciliates may be used to indicate the coastal water quality status of a given site.     

利用新版GRACE时变模型反演珠江流域陆地水储量变化

本文以CSR05、GFZ05、JPL05、ITSG-Grace2016、CSR06、GFZ06、JPL06及ITSG-Grace2018等8种GRACE时变重力场模型作为研究对象,通过300 km高斯滤波和Swenson方法等数据处理策略去除时变模型的噪声,反演2005-01~2012-12珠江流域的陆地水储量变化,并利用ITSG-Grace2018模型、GLDAS水文模型、降水数据、实测地下水数据等资料对珠江流域的陆地水储量变化进行综合分析。结果表明：1）3大官方机构发布的2006版GRACE时变模型的解算精度较2005版有显著改善,ITSG-Grace2018模型的精度也较ITSG-Grace2016有一定的改善,且新版在不同时变模型间的差异更小;2）ITSG-Grace2018模型反演的珠江流域陆地水储量整体呈上升趋势,其季节性变化特征与GLDAS水文模型、降水数据及地下水测井监测数据具有较好的一致性。     

珠江口西岸土地利用景观格局变化及驱动力分析

通过目视解译获取了珠海市沿海区域1995、2000和2003年的土地利用数据。利用ArcGIS软件获取了各种土地利用类型的面积变化数据,以及由模型运算得到不同时期研究区的土地利用分维度、分离度、破碎度、多样性等景观指数,对不同时期的土地利用面积变化,以及各景观指数的变化机理进行了分析。结果表明,珠江口西岸的土地利用变化主要表现为耕地面积不断减少,尤其2000年以后减少的更为剧烈;而林地、建设用地、水域的面积相应的有不同程度的增长。土地利用格局的变化,致使景观指数的变化,诸如,2003年的分离度、分维度等都高于前两个时期,而土地利用多样性指数也逐年增长。造成这些变化的主要驱动力有人口的增长,对土地经济效益的追求,政府政策的影响以及海岸带的区位优势等。     

BIOGEOCHEMICAL BEHAVIOR OF NUTRIENTS AND THEIR FLUXES IN THE MINJIANG RIVER ESTUARY

IMRODUcTlONThe577km1ongMinjiangRiver,thelongestriverinFujianProvinceofChina,hasa6O992km2drainagebasin.Thewaterdischargeislarge(meaninyearsis198Om/s).TheannualrunofffromtheMinjiangRiveris5.84xlOlom,WhichismorethanthatoftheHuangheRiver,andranksthirdintheannualrunoffofmaorChineseriversWhang,l994).SimdentnutrientSfromtheMinjiangRivertotheseaisanarisa-ryconditionforthefonnationandcontinuingexistenceoftheMindongFisheryGroundandtheMihahongFisheryGround.Inthendingareaofriverwaterwithseaw…     

Occurrence and distribution of dissolved tellurium in Changjiang River estuary

With the implementation of the GEOTRACES program, the biogeochemical cycle and distribution of tellurium （Te） in marine environments are becoming increasing environmental concerns. In this study, the concentration of dissolved Te in the Changjiang （Yangtze） River estuary and nearby waters was determined in May 2009 by hydride-generation atomic fluorescence spectrometry to elucidate the abundance, dominant species, distribution, and relationship with environmental factors. Results show that： （1） dissolved Te was low owing to its low abundance in the Earth＇s crust, high insolubility in water, and strong affinity to particulate matter; （2） Te（IV） and Te（VI） predominated in surface water. Te（VI） was the dominant species in bottom water, and Te（IV） was the minor species; （3） Horizontally, resulting from low phytoplankton metabolism and the weak reduction from Te（VI） to Te（IV） in the shore, Te（IV） was concentrated in the central zone instead of the coastal region. However, Te（VI） was abundant near the mouth of the Changjiang River where the Changjiang water is diluted and in the area to the south where the Taiwan Warm Current invaded. In the adsorption-desorption process, Te（IV） was negatively related to suspended paniculate matter （SPM）, indicating that it was adsorbed by particulate matter. While for Te（VI）, the positive correlation with SPM suggested that it was desorbed from the solid phase. In the estuary, dissolved Te had a negative correlation to salinity. However, it deviated from the dilution line in high-salinity regions due to the invasion of the Taiwan Warm Current and the mineralization of organic matter. The relationship between Te（IV） and SPM nutrients indicated that it was more bioavailable and more related to phosphorus than to nitrogen. Progress in the field is slow and more research is needed to quantify the input of Te to the estuary and evaluate the biochemical role of organisms.     

Carbon flux in Pearl River Estuarine Bays

The Pearl River Delta is a unique and extremely complicated ecological system remarkably influenced by runoff. Investigation data obtained in March of 1987 were studied and used to calculate the transformation rate, of carbon, the transformation coefficients of river water and seawater, and the flux coefficient of carbon in the reservoirs in the three estuarine bays (Lingdingyang, Modaomen and Yamen) of the Pearl River. This project was supported by the National Science Foundation of China.     

Geochemical characteristics of phosphorus near the Huanghe River estuary

INTRODUCTIONPhosphorus (P)isanimportantlimitingelementinglobaloceanicproductivity (Holland ,1 978) ,soknowledgeofPisakeytobetterunderstandingofthecyclingofcarbon ,nitrogen,sulfur,andothernu trientelements.Inasimplemassbalancemodel,thelevelofdissolvedPintheoceanisafunctionoftherateofinputviarivers,andtherateofoutputviadepositioninsediments.Inthepresentstudy,thefocusisontheriverinePinputbytheHuangheRiver (YellowRiver)totheBohaiSea,andespeciallyontheamountofPsolubilizedfromsolidphasesupo…