三沙湾海水增养殖区表层溶解氧变化特征及有机污染评价

【目的】研究三沙湾海水增养殖区溶解氧的动态变化及有机污染状况。【方法】利用2014年三沙湾水质的监测结果,分析调查区表层溶解氧变化特征,以及与水温、无机氮、活性磷酸盐之间的相关性,采用单因子指数法和有机污染指数法分别对调查区溶解氧和有机污染进行评价。【结果与结论】调查区内共布设9个水质监测站位,于2014年1、5、8、9、10月分别采集调查区的表层水样。调查区溶解氧质量浓度在4.44～8.60 mg/L之间,平均值为6.29 mg/L,除8月有2站次和9月有5站次的测值处于三类海水水质标准外,其余均处于一、二类海水水质标准水平;溶解氧季节变化明显呈冬季>春季>秋季>夏季的变化规律,平面分布总体呈西北部高,东南部低的变化特征;结合历史资料分析长期变化趋势,溶解氧总体呈现下降趋势,尤其在2000年下降幅度较为明显,这跟三沙湾沿岸带的经济发展对环境影响有关;溶解氧与水温之间呈现极为显著(r=-0.9464)的负相关关系,与无机氮和硝酸盐氮之间均呈现极为显著(r=0.827 5,r=0.821 3)的正相关关系,与活性磷酸盐之间呈现显著(r=0.5413)的正相关关系,说明水温是影响溶解氧变化的首要因子,无机氮和硝酸盐氮以及活性磷酸盐也是影响溶解氧变化的重要因子;从单因子指数来看,在整个调查期间溶解氧污染指数大于1.0的达到15.6%,说明该站点水质已受该因子污染;从有机污染指数来看,调查区水质状况处在开始受到污染状态。     

考洲洋底质中硫化物的含量与分布

1 999年 2月和 8月对考洲洋底质硫化物状况进行了调查。结果表明 :考洲洋底质中的硫化物含量在 1 3 7～ 2 2 8 7mg·kg- 1(干重 ,下同 )之间 ,平均值为 1 2 8 2mg·kg- 1。其含量呈养殖区 >河口入海区>近湾口区非均匀分布。丰水期间底质硫化物含量略高于枯水期的。底质硫化物含量与底质有机质含量和化学耗氧量的呈正相关关系。以全国海岸带污染调查关于底质硫化物含量标准 (3 0 0mg·kg- 1)比较 ,硫化物含量未出现超标现象 ;与其它海湾比较 ,其含量高于海南的安游湾而低于或远低于深圳湾、红海湾、衙前湾、南澳湾和雷州湾以及厦门西海域和大连湾     

Distribution and Sources of Organic Matter in Surface Sediments of the Northern Bering and Chukchi Seas by Using Bulk and Tetraether Proxies

The organic matter (OM) preserved in Arctic Ocean sediments is of great importance to the global carbon budget. How-ever, works that apply multiple proxies to determine the distribution and concentration of organic carbon (OC) in the surface sedi-ments of the northern Bering and Chukchi Seas remain limited. Here a multiproxy approach based on bulk OM parameters and the branched vs. isoprenoid tetraether (BIT) index was used to investigate the distribution and sources of OM in the surface sediments of the northern Bering and Chukchi Seas. Binary and ternary mixing models were applied to trace the contribution of different OC sources to the total OC in the study area. The δ13C values of the sediments provided by the binary model showed that the proportion of terrestrial OC fell in the range of 27.4%–79.8% (46.2% on average). The BIT index returned the lowest fraction (4.8%–27.3%, 12.0% on average). The ternary mixing model was employed to determine the plant-, soil-, and marine-derived fractions of the total OM. The ternary model showed that 11.5%±6.3%, 31.4%±9.5%, and 57.1%±12.4% of OM in the sediment of the study area was derived from soil, plants, and marine sources, respectively. The differences in OM composition between the west and east sides of the Chukchi Sea were controlled by OM inputs from key water masses (i.e., Anadyr Water and Alaska Coastal Water), river discharge, and the nutrient supply from the Pacific inflow that supports marine productivity.     

Distribution and Ecological Risk Assessment of HCHs and DDTs in Surface Seawater and Sediment of the Mariculture Area of Jincheng Bay,China

The distribution of hexachlorocyclohexanes(HCHs) and dichlorodiphenyltrichloroethanes(DDTs) in the surface seawater and sediment of Jincheng Bay mariculture area were investigated in the present study. The concentration of total HCHs and DDTs ranged from 2.98 to 14.87 ng L-1 and were 0.032 ng L-1, respectively, in surface seawater, and ranged from 5.52 to 9.43 and from 4.11 to 6.72 ng g-1, respectively, in surface sediment. It was deduced from the composition profile of HCH isomers and DDT congeners that HCH residues derived from a mixture of technical-grade HCH and lindane whereas the DDT residues derived from technical-grade DDT and dicofol. Moreover, both HCH and DDT residues may mainly originate from historical inputs. The hazard quotient of α-HCH, β-HCH, γ-HCH and δ-HCH to marine species was 0.030, 0.157, 3.008 and 0.008, respectively. It was estimated that the overall probability of adverse biological effect from HCHs was less than 5%, indicating that its risk to seawater column species was low. The threshold effect concentration exceeding frequency of γ-HCH, p,p'-DDD, p,p'-DDE and p,p'-DDT in sediment ranged from 8.3% to 100%, and the relative concentration of the HCH and DDT mixture exceeded their probable effect level in sediment. These findings indicated that the risk to marine benthos was high and potentially detrimental to the safety of aquatic products, e.g., sea cucumber and benthic shellfish.     

The Sources and Transport Patterns of Modern Sediments in Hangzhou Bay: Evidence from Clay Minerals

Clay mineral compositions of 199 offshore surface sediment samples collected from the Hangzhou Bay have been analyzed. The clay minerals in the sediments from the Hangzhou Bay are dominated by illite(58.7%, on average), followed by chlorite(20.3%), kaolinite(16.9%) and smectite(4.1%). Two provinces were classified by Q-mode cluster analysis. Class Ⅰ with relatively low amounts of illite and smectite is widely distributed in the Hangzhou Bay, especially concentrated in the top and mouth of the bay, and the northern and southern nearshore areas. Class Ⅱ with comparatively high amounts of illite and smectite is mainly concentrated in the central part of the bay with the water depth of 8–10 m. By comparing clay mineral compositions with the neighbouring regions, we can find that the sediments in the Hangzhou Bay are mainly influenced by the resuspension and repeated deposition of particles from the Yangtze River due to the strong dynamic environment. In particular, the clay fraction of Class Ⅰ is mainly supplied by the Yangtze River, while the sediments of Class Ⅱ are mixture of the clay minerals carried by the Yangtze River and Qiantang River. In general, the distributions of clay minerals in the northern bay are affected by Yangtze River runoff, coastal current and flood tide together, and in the southern they are mainly affected by the Qiantang River runoff and ebb tide.     

红海湾底质硫化物的分布和变化

根据南海区半封闭型海湾规模化养殖技术研究的需要,对红海湾底质硫化物进行了研究。用碘量法分析的结果表明：红海湾底质中硫化物含量的区域分布极不均匀,呈北部河口区＞虾池＞鱼湾＞中部＞南部自然水域＞礁滩区的特点。虾池、鱼的硫化物含量清淤前分别为清淤后的8.4、3．6倍;湾南部硫化物含量春季明显高于夏季,其余区域的两季差异不明显。46份样品中约13％、28％分别超过国内外评价标准,超标测站位于河口和清淤前的虾池、鱼。礁滩护养增殖区、南部自然水域、湾中部牡蛎养殖区和清淤后的虾池、鱼尚未见硫化物的污染。     

红海湾水产养殖示范区水质综合评价

红海湾是广东省非常重要的海水养殖示范区。为了维系和保护红海湾规模化水产养殖示范区的优良生态环境 ,1 997年 4月至 1 998年 1 2月对红海湾水域水质的时空变化趋势和质量状况进行了研究与评价。结果表明 ,红海湾海水综合质量总体上处于相对清洁水平 ,但浅海养殖区和长沙湾养殖区有机污染明显 ,分别达富营养化和高富营养化程度。DIN和IP是水质富营养化的主要因素 ,而石油类、Cu、COD是重点控制的优先污染物。     

湛江湾沉积物中氨氧化微生物的丰度、多样性和分布特征

【目的】分析湛江湾沉积物中氨氧化古菌(AOA)和氨氧化细菌(AOB)的丰度与多样性。【方法】采用分子生态学方法。【结果】AOA amoA基因丰度范围为3.23×10~5~5.27×10~6 copies·g~(-1)(以干土计),AOB amoA基因丰度范围为2.99×10~4~1.06×10~7 copies·g~(-1)(以干土计),两者平均丰度差别不大;但对于潮下带,大部分站位AOA amoA基因丰度高于AOB,且与氨氮和有机碳含量显著正相关。在工厂排污口和养殖区AOA多样性高于其他站位,而AOB则相反,说明AOA对环境污染物有更强的适应能力。系统发育分析显示,88%的AOA amoA序列属于海洋簇Group I.1a,优势类群是一类喜热带气候的AOA新分支;潮下带亚硝化螺菌属AOB为优势种群,而潮间带亚硝化单胞菌属AOB为优势种群。CCA分析表明,盐度和pH显著影响湛江湾AOA与AOB的群落结构。【结论】湛江湾沉积物中氨氧化微生物的分布与氨氮、总有机碳、盐度、pH等多种环境因子密切相关。     

湖北清江岩溶洞穴现代土壤有机碳同位素与生物标志物指标变化规律

为进一步理解中国南方岩溶区现代土壤生物有机地球化学演化规律,对采自湖北清江流域典型岩溶洞穴上覆土壤开展了
系统的分析。分别采用稳定同位素质谱仪(MAT-251)与气相色谱质谱仪(GC-MS)测试了样品中的有机碳同位素与生物标志物指标。
其中有机碳同位素值(δ13C_org)在-28.3‰~-27.4‰之间变化,并随深度的增大呈逐渐正偏的趋势,指示了当地的植被类型自土壤
层形成以来主要为C3 植物。而可抽提有机质的总量、正构烷烃高碳数奇偶优势(CPIh 值)、高碳数与低碳数含量比值(Rh/l值)、平均
链长(ACL 值)以及脂肪酸C16:1/C16:0等指标随土壤剖面深度的增大呈现逐渐降低的趋势,与土壤有机碳同位素的变化趋势基本一
致,说明岩溶地区表层土壤中有机碳同位素和生物标志物均与土壤层内微生物活动的强弱密切相关。另一方面,也暗示了有机碳源
是制约岩溶地区土壤微生物活动的重要因素之一。为进一步深入理解湖北清江和尚洞洞穴石笋记录提供了新的思路。      

Seasonal Variation of Biochemical Components in Clam(Saxidomus purpuratus Sowerby 1852) in Relation to Its Reproductive Cycle and the Environmental Condition of Sanggou Bay,China

Seasonal variation of biochemical components in clam(Saxidomus purpuratus Sowerby 1852) was investigated from March 2012 to February 2013 in relation to environmental condition of Sanggou Bay and the reproductive cycle of clam.According to the histological analysis,the reproductive cycle of S.purpuratus includes two distinctive phases:a total spent and inactive stage from November to January,and a gametogenesis stage,including ripeness and spawning,during the rest of the year.Gametes were generated at a low temperature(2.1℃) in February.Spawning took place once a year from June to October.The massive spawning occurred in August when the highest water temperature and chlorophyll a level could be observed.The key biochemical components(glycogen,protein and lipid) in five tissues(gonad,foot,mantle,siphon and adductor muscle) were analyzed.The glycogen content was high before gametogenesis,and decreased significantly during the gonad development in the gonad,mantle and foot of both females and males,suggesting that glycogen was an important energy source for gonad development.The protein and lipid contents increased in the ovary during the gonad development,demonstrating that they are the major organic components of oocytes.The lipid and protein contents decreased in the testis,implying that they can provide energy and material for spermatogenesis.The results also showed that protein stored in the mantle and foot could support the reproduction after the glycogen was depleted.     

Distribution and Sources of Particulate Organic Matter in the Northern South China Sea: Implications of Human Activity

In order to understand origin and fate of particulate organic matter,the isotopic composition (δ~(13)C and δ~(15)N),total organic carbon content,total nitrogen content,and C/N ratios were measured for suspended particulate organic matter (POM) collected from the northern South China Sea (NSCS) during summer.Our study revealed that δ~(13)C generally decreased from land to sea,and elevated δ~(13)C occurred at the nearshore stations,suggesting that POC was mainly contributed from the eutrophic level and microbial activity.Moreover,the distribution of δ~(15)N values were complicated,and heterotrophic modification was responsible for higher δ~(15)N in the nearshore stations.These distribution patterns of δ~(13)C and δ~(15)N in the nearshore stations may be associated with the intensification of human activity in the coast.Based on the Stable Isotope Analysis in R model,65% of POM was contributed by marine organic matter in the NSCS,20% by terrestrial inputs,and 15% by freshwater algae.     

Seasonal Variations of Terrestrial OC Sources in Aerosols over the East China Sea: The Influence of Long-Range Air Mass Transport

Aerosols represent an important source of terrestrial organic carbon (OC) from the East Asian continent to the China marginal seas,thus their provenance and transport play important roles in the global carbon cycle.Fifty samples of total suspended particle were collected seasonally from the nearshore Huaniao Island (HNI) in East China Sea (ECS) from April 2018 to January2019;and they were analyzed for total organic carbon (TOC) content and stable carbon isotope (δ~(13)C),as well as terrestrial biomarkers including n-alkanes (C_(20)-C_(33)),n-alkanols (C_(20)-C_(32)) and n-fatty acids (n-FAs,C_(20)-C_(30)),to distinguish the seasonal variabilities of terrestrial OC sources and reveal the influence of the long-range air mass transport on these sources.The TOC-δ~(13)C values(range from-27.3‰to-24.3‰) and molecular distributions of terrestrial biomarkers both suggested that terrestrial OC contributions to aerosols had significant seasonal variations.The source indices of terrestrial biomarkers (e.g.,Fossil%=82.8%for n-alkanes)revealed that the fossil fuel OC contributions,including coal burning and vehicular emission,were higher in winter,mainly because of the long-range air mass transport from the north of the East Asian continent.The terrestrial plant OC contributions were higher in summer (e.g.,Wax%=32.4%for n-alkanes),likely due to local vegetation sources from HNI and East Asian continental air masses.Cluster analysis of air mass backward-trajectories clearly showed that transport pathway plays an important role in determining the organic constituents of aerosols in China marginal seas.A comparison of these terrestrial OC contributions from different air mass origins suggested that fossil fuel OC showed less variations among various air mass origins from northern China in winter,while terrestrial plant OC sources from northern and southern China in summer contributed more than that from the air masses transported through the ECS.These results provided a basis for future quantification of terrestrial OC from different origins in marine aerosols,by combining biomarker index and carbon isotopes.     

Applicability of Perinereis aibuhitensis Grube for Fish Waste Removal from Fish Cages in Sanggou Bay,P.R.China

The present study investigated the applicability of integrated polychaete-fish culture for fish waste removal to offset negative impact induced by organic benthic enrichment.A field study demonstrated that deposition rate was significantly higher underneath the fish farm than that in control area.The material settling under the farm was characterized by a high amount of fish feces(45%) and uneaten feed(27%).Both feeding rate(FR) and apparent digestibility rate(ADR) increased with decreasing body weight,as was indicated by significantly a higher rate observed for the groups containing smaller individuals in a lab study.The nutrient in fresh deposited material(De) was higher than that in sediments collected under the farm(Se),resulting in lower feces production but higher apparent digestibility rate for the De group as feeding rate was similar.Consequently,higher nutrient removal efficiency was observed in the De group.A mass balance approach indicated that approximately 400–500 individuals m~(-2) is required for removing all waste materials deposited underneath the fish farm,whereas abundance can be lower(about 300–350 individuals m~(-2)) when only the fish waste needs to be removed.The results showed that a significant amount of waste had been accumulated in the fish cages in Sanggou Bay.The integration of fish with P.aibuhitensis seems promising for preventing organic pollution in the sediment and therefore is an effective strategy for mitigating negative effect of fish farms.Thus such integration can become a new IMTA(integrated multi-trophic aquaculture) model in Sanggou Bay.     

Sediment Characteristics,Sources, and Transport Patterns in Kompong Som Bay,Cambodia: Indications from Grain Size and Heavy Minerals

In this paper, we analyzed the grain size and heavy mineral compositions of 52 surface sediment samples collected from the Kompong Som Bay of Cambodia and the adjacent rivers to depict the marine sedimentary environments and transport processes. Heavy minerals in sediments are dominated by authigenic pyrite, siderite, and tourmaline, with average percentages of 36.52%, 29.02%, and 10.94%, respectively. Two provinces can be divided according to the spatial similarity of minerals. The sediments from Province I, covered by silt grains in the northern bay, are characterized by autogenic pyrite, indicating a weakly reducing environment;whereas in Province II, covered by sand grains in the southern bay, the siderite-tourmaline-authigenic pyrite-zircon-hornblende assemblage occurs, indicating a mild reducing environment and locally oxidizing environment. Most of the sediments in the Kompong Som Bay are introduced from the Preak Piphot River and Srae Ambel River, except that some of them in the south areas come from coastal erosion. Generally, the sediments are difficult to be transported because of the low sediment loads entering the sea and weak hydrodynamic conditions. However, they are transported from the north to the south during the tide ebbing when the hydrodynamic force is much stronger. The sediment distribution and transport patterns are controlled by many factors, including submarine topography, hydrodynamic conditions, the southwest monsoon, land contours, and sediment supply.     

Seasonal community structure of mesozooplankton in the Daya Bay, South China Sea

Mesozooplankton are key components of coastal ecosystems, linking the microbial food web to the classic food chain. In this study, species composition and abundance of mesozooplankton is studied for the Daya Bay in April (spring) and October (fall), 2006. A total of 27 species of mesozooplankton were identified in spring and 58 species in fall. Dominant species were Oithona tenuis, Flaccisagitta enflata, Penilia avirostris and Centropages tenuiremis in spring, shifting to Microsetella norvegica, Oithona tenuis and Parvocalanus crassirostris in fall. Higher mesozooplankton abundance was found at Aotou Cove and Dapeng’ao Cove compared to other stations, indicating the influence of eutrophication on mesozooplankton community in the Daya Bay. The outbreak of Noctiluca scintillans bloom in spring reduced the species diversity and abundance of mesozooplankton.     

Paleosalinity and Its Association with Organic Matter: A Case Study from the Eocene Shahejie Formation,Laizhou Bay Sag,Bohai Bay Basin(China)

Paleosalinity is vital for the paleoenvironmental reconstruction and affects the formation of source rock.The lowermiddle sections of the third member of Eocene Shahejie formation (Es_3~(M-L)) constitute the most important source rock layer in Laizhou Bay Sag.However,the paleosalinity of the depositional water in which Es_3~(M-L) submembers are deposited remains unclear.A series of integrated experiments,including major and trace elements,X-ray diffraction,total organic carbon,and Rock-Eval,was performed to reveal the paleosalinity and its relationship with organic matter (OM).Various inorganic proxies (Sr/Ba,Rb/K,B/Ga,Walker’s paleosalimeter,Adam’s paleosalimeter,and Couch’s paleosalimeter) were employed to determine the paleosalinity of samples.Prominent differences existed in the proxies.Couch’s paleosalimeter is the most reliable and qualitative approach for Laizhou Bay Sag.Samples from the lake center (depocenter) and margin showed paleosalinities from 4.92 wt‰to 9.73 wt‰,suggesting a ubiquitous brackish (oligohaline-mesohaline) water body in the paleolake.Molybdenum enrichment in samples indicates an oxygendepleted (suboxic or anoxic) condition.The increase in salinity has a certain but non-significant positive correlation with oxygen reduction.This condition may be attributed to the weak stratification of the water column in brackish water bodies.Moreover,paleosalinity has a weak and indirect relationship with OM accumulation during the deposition of Es_3~(M-L) submembers in Laizhou Bay Sag.     

云南金顶铅锌矿床成矿物质来源及有机成矿作用

分析了金顶铅锌矿床同位素及生物标志化合物特征,探讨了矿床成矿物质来源及有机成矿作用.结果表明,矿石铅主要来自上地幔,成矿流体主要为地幔流体和盆地卤水.矿区有机质的母质来源以低等水生生源的海藻类为主,同时伴随有一定量的陆源高等植物组分的输入,有机质来源于三叠纪三合洞组碳酸盐岩地层.有机质在成矿作用中可能起到的作用有:还原硫酸盐提供成矿所需的硫源;形成有机金属络合物,活化运移成矿金属元素;改变成矿物理化学环境对成矿物质的还原沉淀作用.     

Species Composition and Diversity of Macrobenthos in the Intertidal Zone of Xiangshan Bay,China

Xiangshan bay is a narrow semi-closed bay and situated on the northwestern coast of the East China Sea. Over past decades, it has become to a major bay with intensive human activities, dense urbanized area, and poor water quality. The aim of this paper was to reveal the ecological status through the elucidation of the species composition, abundance, biomass and diversity of macrobenthos in this bay. Six intertidal sections were surveyed from January 2007 to November 2008 quarterly. Sections TG, HD and XH are located in the three inner bays, sections QJ and WS are located near the thermal power plants, and section XX is located at the outer part of Xiangshan Bay. Great variations in macrobenthos community were indentified, and the species composition of the community in the present study showed the dominance in the order of molluscs(bivalves and gastropods), crustaceans and others, and only few Polychaeta were recorded. Only three dominant species, Littorina brevicula, Ilyplax tansuiensis, and Cerithidea cingulata were collected in all the sections, and a total of 19 dominant species were recorded only in one section. Two-way ANOVA analyses of abundance indicated that there were significant differences among sections or seasons. Shannon-Wiener diversity index(H’) had its maximum(2.45) in section QJ, and minimum(1.76) in section TG. Multiple irregular k-dominance plots clearly showed that the study area was polluted and the macrobenthos community was under stress. We conclude that the macrobenthos of Xiangshan Bay have been disturbed by human activities, especially at the interior bay.