Contrasting time trends of organic contaminants in Antarctic pelagic and benthic food webs     

van den Brink NW  Riddle MJ  van den Heuvel-Greve M  van Franeker JA 《Marine pollution bulletin》2011,62(1):128-132

We demonstrate that pelagic Antarctic seabirds show significant decreases in concentrations of some persistent organic pollutants. Trends in Adélie penguins and Southern fulmars fit in a general pattern revealed by a broad literature review. Downward trends are also visible in pelagic fish, contrasting sharply with steady or increasing concentrations in Antarctic benthic organisms. Transfer of contaminants between Antarctic pelagic and benthic food webs is associated with seasonal sea-ice dynamics which may influence the balance between the final receptors of contaminants under different climatic conditions. This complicates the predictability of future trends of emerging compounds in the Antarctic ecosystem, such as of the brominated compounds that we detected in Antarctic petrels. The discrepancy in trends between pelagic and benthic organisms shows that Antarctic biota are still final receptors of globally released organic contaminants and it remains questionable whether the total environmental burden of contaminants in the Antarctic ecosystem is declining.  相似文献   

池塘瓦片参礁养殖刺参的呼吸环境研究     

杨秀兰  杨建敏  刘相全  宋向军  张宇  王爱敏  臧金健 《海洋湖沼通报》2011,(2):20-26

研究了用瓦片参礁池塘养殖刺参(Apostichopus japonicus)的底层溶氧条件和呼吸环境;测定获得11.5～15.3℃时,新、老池塘瓦片参礁的平均增氧量分别为1.96mgO2/Ld与3.15mgO2/Ld(或1.17 gO2/m2d与2.30 gO2/m2d),相应底栖硅藻生物量为14.61 g/m2与48...  相似文献   

Changes in North Sea macrofauna communities and species distribution between 1986 and 2000     

Ingrid KrönckeHenning Reiss  Jacqueline D. EggletonJohn Aldridge  Magda J.N. BergmanSabine Cochrane  Johan A. CraeymeerschSteven Degraer  Nicolas DesroyJean-Marie Dewarumez  Gerard C.A. DuineveldKarel Essink  Hans HillewaertMarc S.S. Lavaleye  Andreas MollStefan Nehring  Richard NewellEivind Oug  Thomas PohlmannEike Rachor  Mike RobertsonHeye Rumohr  Michaela SchratzbergerRebecca Smith  Edward Vanden Berghe  Jan van DalfsenGert van Hoey  Magda VincxWouter Willems  Hubert L. Rees 《Estuarine, Coastal and Shelf Science》2011,94(1):1-15

The North Sea Benthos Project 2000 was initiated as a follow-up to the 1986 ICES North Sea Benthos Survey with the major aim to identify changes in the macrofauna species distribution and community structure in the North Sea and their likely causes.The results showed that the large-scale spatial distribution of macrofauna communities in the North Sea hardly changed between 1986 and 2000, with the main divisions at the 50 m and 100 m depth contours. Water temperature and salinity as well as wave exposure, tidal stress and primary production were influential environmental factors on a large (North Sea-wide) spatial scale.The increase in abundance and regional changes in distribution of various species with a southern distribution in the North Sea in 2000 were largely associated with an increase in sea surface temperature, primary production and, thus, food supply. This can be most likely related to the North Sea hydro-climate change in the late 1980s influenced by the variability in the North Atlantic Oscillation (NAO). Only one cold-temperate species decreased in abundance in 2000 at most of the stations. Indications for newly established populations of offshore non-native species were not found.Differences in macrofauna community structure on localised spatial scales were predominantly found north of the 50 m depth contour off the British coast along the Flamborough Head Front towards the Dogger Bank, off the coast of Jutland and at the Frisian Front. These changes were most likely attributed to stronger frontal systems in 2000 caused by the increased inflow of Atlantic water masses in relation to the hydro-climate change in the late 1980s.  相似文献   

Floating mucus aggregates derived from benthic microorganisms on rocky intertidal reefs: Potential as food sources for benthic animals     

Y. Tamura  M. Tsuchiya 《Estuarine, Coastal and Shelf Science》2011,94(3):199-209

Mucus films, flocs or foams consisting of fine sand, algae and detritus frequently occur in the surface waters of rocky intertidal reef flats during incoming tide. These masses are referred to as mucus aggregates. We examined the developmental process of mucus aggregates and their abundance, distribution, migration and trophic composition. The trophic composition of mucus aggregates was then compared to those of sediments to evaluate their potential nutritional value for benthic animals. The organic matter content, chlorophyll a concentration, microalgal density and bacteria-derived fatty acid contents of mucus aggregates were higher than those observed in sediment, suggesting that mucus aggregates contain not only high levels of organic matter but also dense concentrations of microalgae and bacteria; therefore, mucus aggregates may serve as a qualitatively more energetic food source for benthic fauna compared to sediments. Benthic diatoms were the most abundant organisms in mucus aggregates. Large numbers of diatoms were trapped in fine mineral particles and mucilage-like strings, suggesting that a portion of the mucus is secreted by these benthic microalgae.Mucus aggregate accounted for only 0.01-3.9% of the daily feeding requirements of the dominant detritivore, Ophiocoma scolopendrina (Echinodermata: Ophiuroidea) over the entire sampling area. In contrast, for the species population on the back reef, where mucus aggregates ultimately accumulate, mucus aggregates provided from 0.4 to 113.3% of food for this species. These results suggest that mucus aggregate availability varies spatiotemporally and that they do not always provide adequate food sources for O. scolopendrina populations.  相似文献   

Food web structure of sandy beaches: Temporal and spatial variation using stable isotope analysis     

Leandro Bergamino  Diego Lercari  Omar Defeo 《Estuarine, Coastal and Shelf Science》2011,91(4):2751

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Detecting Vulnerable Marine Ecosystems in the Southern Ocean using research trawls and underwater imagery     

Christopher D. Jones  Susanne J. Lockhart 《Marine Policy》2011

To ensure that destructive bottom fishing activities do not have significant adverse impacts on Vulnerable Marine Ecosystems (VMEs) in high seas areas of the World Ocean, as required by United Nations General Assembly Resolution 61–105, knowledge of the locations of VMEs is required. Quantifying the occurrence and abundance of VME indicator taxa in research bottom-trawl samples, as well as from in situ observations with underwater photography, provides methods for detecting these ecosystems. A case study is presented in which a threshold density of indicator taxa was used as the basis for VME designation. In 2009, high densities of VME indicator taxa were encountered at 11 sites off th`e South Orkney Islands in the Atlantic sector of the Southern Ocean. In most cases, thresholds were exceeded by a limited number of VME indicator taxa, primarily representatives of the class Demospongiae (siliceous sponges), Hexactinellida (glass sponges) and Ascidiacea (tunicates). In situ imagery further showed the importance of bryozoans (lace corals), scleractinians (stony corals) and stylastrids (hydrocorals) in the study region. The approach outlined here, which relies on widely used sampling techniques, could be employed throughout the World Ocean to detect and document the presence of VMEs from existing datasets. To illustrate this point, the method was applied to a separate dataset, collected in 2006, from a research cruise off the northern Antarctic Peninsula, which led to the detection of 17 VMEs. The VMEs from both the 2006 and 2009 data are now registered and influence the management of fisheries in the Southern Ocean.  相似文献   

Recycling of oceanic crust and the origin of intraplate volcanism     

A. D. Smith 《Australian Journal of Earth Sciences》2013,60(6-7):675-680

Source models for intraplate volcanism (IPV) include vertical introduction of material from deep in the mantle (plume model), contamination of the shallow mantle (perisphere and continental mantle delamination models) and derivation by selective partial melting of oceanic crust recycled into the depleted mantle (SUMA/streaky mantle models). The plume hypothesis became the ruling model after a flawed interpretation of helium isotope data in the mid 1980s that led to plumes being imposed on models for crustal recycling into the depleted mantle. This incorporation of otherwise competing concepts, is the cause of unnecessary complexity in modern geodynamic models. The plume model cannot explain all manifestations of IPV and a comprehensive explanation can only be found by invoking the alternative options, combined with their tapping by plate tectonic processes.  相似文献   

Aquifer storage and recharge: Innovation in water resources management     

S. R. Barnett  S. R. Howles  R. R. Martin  N. Z. Gerges 《Australian Journal of Earth Sciences》2013,60(1):13-19

Stormwater and treated sewerage effluent, previously regarded as waste, are now being reused in South Australia through the innovative aquifer storage and recharge technique. After pretreatment in wetlands, this water is stored in otherwise unused brackish aquifers for summer irrigation of parklands. Trials are underway using recycled water from the Bolivar Wastewater Treatment Plant for irrigation of market gardens. This paper presents several case studies where the aquifer storage and recharge technique has been successful, with savings in water and infrastructure costs, as well as providing environmental benefits.  相似文献   

高浓度示差分光光度法测定钢厂循环管道除垢污水中的总磷     

柴昌信  王建波  黑文龙  陈月源  祝建国 《岩矿测试》2012,31(6):985-988

循环水及污水中总磷的国家标准方法是用分光光度法测定,当样品中有机磷含量高时,分解易碳化,操作繁琐,分析误差大.本文应用磷钼黄显色示差分光光度技术测定某钢厂循环管道除垢污水中的总磷,通过正交实验确立了采用硝酸-高氯酸消解样品,将样品中聚磷酸盐、有机磷酸盐转化为正磷酸盐,在硝酸溶液中,正磷酸盐与钒钼酸铵作用生成可溶性黄色磷钒钼酸配合物,基于其颜色强度与磷的浓度成正比测定高浓度磷的含量.实验对使用的氧化剂用量、溶解温度、显色条件、测定波长进行优化,结果表明,磷含量在10.0 ～ 40.0 mg/L范围符合朗伯-比尔定律,方法精密度(RSD)＜1.0％(n=5),加标回收率为98.8％～105.0％.建立的示差光度法比一般光度法相对误差小,准确度更高;与电感耦合等离子体发射光谱法的测定结果基本吻合,且测定成本更低.  相似文献   

GRACE重力计划在揭示地球系统质量重新分布中的应用   总被引：3，自引：0，他引：3  

黄珹  胡小工 《天文学进展》2004,22(1):35-44

2002年3月成功发射的美德合作卫星重力计划GRACE(Gravity Recovery And ClimateExperiment),即将提供空间分辨率约为200 km而时间分辨率为1个月的时变地球重力场模型序列。GRACE计划的星座由两颗相距约220 km,高度保持为300-500 km、倾角保持约90°的近极轨卫星组成。由于采用星载GPS和非保守力加速度计等高精度定轨技术,以及高精度的星一星跟踪数据反演地球重力场,在几百公里和更大空间尺度上, GRACE重力场的精度大大超过此前的卫星重力计划。根据GRACE时变重力场反演的地球系统质量重新分布,将对固体地球物理、海洋物理、气候学以及大地测量等应用有重要的意义。虽然其设计寿命只有5 yr,但研究表明GRACE的结果可用于研究北极冰长期时间尺度的变化,并进而研究极冰融化对全球气候变化,特别是对海平面长期变化的影响。在季节性时间尺度上,利用GRACE重力场反演的质量重新分布足以揭示平均小于1 cm的地表水变化,或小于1 mbar。的海底压强变化。除了巨大的社会效益和经济效益外,这些变化对了解地球系统的物质循环(主要是水循环)和能量循环有非常重要的意义。介绍GRACE重力场揭示的地球系统质量重新分布,为理解其地球物理应用提供必需的准备;同时针对我国大陆和沿海地区的地球物理应用提出初步的设想。  相似文献