A community-wide intercomparison exercise for the determination of dissolved iron in seawater     

Andrew R. Bowie  Eric P. Achterberg  Peter L. Croot  Hein J.W. de Baar  Patrick Laan  James W. Moffett  Simon Ussher  Paul J. Worsfold 《Marine Chemistry》2006

The first large-scale international intercomparison of analytical methods for the determination of dissolved iron in seawater was carried out between October 2000 and December 2002. The exercise was conducted as a rigorously “blind” comparison of 7 analytical techniques by 24 international laboratories. The comparison was based on a large volume (700 L), filtered surface seawater sample collected from the South Atlantic Ocean (the “IRONAGES” sample), which was acidified, mixed and bottled at sea. Two 1-L sample bottles were sent to each participant. Integrity and blindness were achieved by having the experiment designed and carried out by a small team, and overseen by an independent data manager. Storage, homogeneity and time-series stability experiments conducted over 2.5 years showed that inter-bottle variability of the IRONAGES sample was good (< 7%), although there was a decrease in iron concentration in the bottles over time (0.8–0.5 nM) before a stable value was observed. This raises questions over the suitability of sample acidification and storage.  相似文献   

黄、东海环流的数值研究Ⅲ——正压环流的数值模拟     

刘桂梅  孙文心  雷坤  江文胜 《中国海洋大学学报(自然科学版)》2002,32(1):1-8

依据黄、东海环流的的动力学模型 ,运用“流速分解法”对黄、东海正压环流进行了数值模拟。计算结果表明冬季黄海正压环流主要受风应力影响 ,基本形态为黄海暖流由济州岛西南进入南黄海中部 ,其东西两侧分别为两支向南流动的沿岸流 ;夏季主要受到潮致体力的影响 ,为一逆时针涡旋。东海环流主要是边界力作用驱动的结果 ,东海黑潮、台湾暖流和对马暖流较稳定。冬季风应力对东海环流表层流场有消弱作用 ,在夏季则有一定增强作用。  相似文献   

绒螯蟹种质资源研究进展   总被引：1，自引：1，他引：1  

张秀梅  柳广东  高天翔 《中国海洋大学学报(自然科学版)》2002,32(4):533-542

本文综述了近年来有关绒螯蟹属在形态学、遗传学和育种学方面的研究进展 ,着重介绍了同工酶、RAPD和 mt DNA技术在绒螯蟹群体遗传学中的应用 ,提出遗传学分类标准的建立是绒螯蟹属分子分类的关键所在。  相似文献   

High-resolution sediment echosounding off Peru: Late Quaternary depositional sequences and sedimentary structures of a current-dominated shelf     

Reinhardt  L.  Kudrass  H.-R.  Lückge  A.  Wiedicke  M.  Wunderlich  J.  Wendt  G. 《Marine Geophysical Researches》2002,23(4):335-351

About 6000 km of both bathymetric and high-resolution acoustic profiles were acquired on the shelf and upper slope offshore Peru between 9° S and 14° S. Two new sediment echosounder systems – SEL-96 and SES-2000DS – provided details of the sedimentary structures of the Quaternary sequences within the Sechura-Salaverry, Huacho and Pisco Basins. To a great extent, the poleward undercurrent determines the distribution of sediments. The undercurrent has generated numerous erosional unconformities, it has winnowed hardgrounds and has created mudwaves common between 250 m and 400 m water depth. Distinct subbottom reflectors within sedimentary units represent hiatuses due to periods of intensified winnowing or non-deposition. Erosional unconformities usually marked by pronounced reflectors suggest shifts of the undercurrent system related to climatic changes and eustatic variations of sea level. On a larger scale, the stacked prograding depositional sequences reflect the sea-level cycles of the Middle Pleistocene to the Holocene. Based on the stratigraphy of our piston cores and that of Ocean Drilling Program (ODP) Site 680, the depositional sequences limited by extended unconformities were assigned to oxygen isotope stages 1 to 7. Other sedimentary structures are small straight channels that were conduits for downslope sediment transport. Deformed sediments associated with synsedimentary normal faults result from creep movements indicating beginning slope failure.  相似文献   

Dynamic evolution of the 1997–1999 El Niño–La Niña cycle in the southern California Current System     

R. J. Lynn  S. J. Bograd   《Progress in Oceanography》2002,54(1-4)

The development of the strongest El Niño event on record in the equatorial Pacific in 1997–1998 and the rapid transition to strong La Niña conditions in 1998–1999 had a large impact on the physical and biological environment of the West Coast. We investigate the evolution of the physical structure and circulation dynamics of the southern California Current System (CCS) during this period based on hydrographic data collected on 25 cruises over a 45-month period (February 1996–October 1999). The El Niño period was characterized by a significant increase in dynamic height, extreme water mass characteristics, a strengthening and broadening of the poleward nearshore flow, and a temporary reversal of net alongshore transport. By early 1999, conditions in the CCS had reversed. The data suggest that remotely driven forcing (propagating oceanic waves) contributed to the anomalies observed during the El Niño period, while the cool-water conditions of 1999 were most likely a result of anomalous local atmospheric forcing.  相似文献   

Nutrient variability during El Niño 1997–98 in the California current system off central California     

C. G. Castro  C. A. Collins  P. Walz  J. T. Pennington  R. P. Michisaki  G. Friederich  F. P. Chavez   《Progress in Oceanography》2002,54(1-4)

Nutrient conditions off central California during the 1997–98 El Niño are described. Data were collected on 11 cruises from March 1997 to January 1999 along a hydrographic section off central California, as well as every two weeks at a coastal station in Monterey Bay. Perturbations associated with El Niño are shown as anomalies of thermohaline and nutrient distributions along this section. The anomalies were obtained by subtracting seasonal averages for the period from April 1988 to April 1991 from the 1997–98 observations. The first indications of El Niño conditions (high sea levels) were observed at Monterey between late May and early June 1997, but the coastal nutricline did not begin to deepen until August 1997. It reached maximum depth of 130 dbar in January 1998 at the time that maximum sea level anomalies were observed. During this period: (1) the highest subsurface temperature anomalies coincided with subsurface nutrient anomaly minima at the depth of the pycnocline; (2) southern saline and nutrient-poor waters occupied the upper 80 dbar of the water column along the entire section; and (3) nitrate levels were close to zero in the euphotic zone, collapsing the potential new primary production in the coastal domain. At the end of February 1998, the nutricline shoaled to 40 dbar at the coast although it remained anomalously deep offshore. Higher temperatures and lower nutrient levels were observed for the entire section through August 1998 although in contrast with the previous winter, there was a strong freshening mainly due to an onshore movement of subarctic waters.  相似文献   

Targeted environmental monitoring for the effects of medicines used to treat sea-lice infestation on farmed fish   总被引：1，自引：0，他引：1  

Davies  I. M.; Rodger  G. K.; Redshaw  J.; Stagg  R. M. 《ICES Journal of Marine Science》2001,58(2):477-485

  相似文献   

Modelling the size selectivities of a trawl codend and an associated square mesh panel   总被引：8，自引：1，他引：8  

Zuur  G.; Fryer  R. J.; Ferro  R. S. T.; Tokai  T. 《ICES Journal of Marine Science》2001,58(3):657-671

  相似文献   

Feeding Habits of Trisopterus minutus capelanus (Gadidae) Off the Eastern Coast of Spain (Western Mediterranean)     

M. Salomé Morte  Manuel J. Redón  & Antonio Sanz-Brau 《Marine Ecology》2001,22(3):215-229

Abstract. The stomach contents of poor cod, Trisopterus minutus capelanus (Lacepède), were taken at monthly intervals off the eastern coast of the Gulf of Valencia (Spain). A total of 1276 were analyzed to determine diet according to fish size and season. The basic food consists of crustaceans (Mysidacea and Decapoda) and teleosts. Feeding habits varied with size: decapods and fishes were more abundant in the stomachs of larger specimens. Little seasonal variation in food habits was recorded.  相似文献   

海藻中类胡萝卜素抗超氧自由基活性研究   总被引：2，自引：0，他引：2  

严小军  范晓  娄清香  刘晓妹 《海洋科学集刊》2001,(43):115-119

在植物组织内，类胡萝卜素除具有集光功能外，还具有其他的重要生物学功能，类胡萝卜素作为光保护剂可抵抗光、氧和光敏色素的有害作用，也可作为化学反应物抵抗细胞所产生的化学物质引起的氧化损伤，保护光合系统免受光动力敏化作用的破坏。类胡萝卜素光保护作用的主要机制如下:(1)类胡萝卜素对三重线态敏化剂的淬灭；(2)类胡萝卜素对1O2的淬灭；(3)类胡萝卜素对自由基反应的抑制，它的这种生物学活性在医学领域也具有重要的应用价值。胡萝卜素在生物系统中的保护作用包括失活由电激活的单线态氧(1O2)，失活反应性的化学物质如过氧化物自由基和烷氧基，这些自由基产生于细胞内，并可能会引起有害的氧化作用。类胡萝卜素的保护功能与直接的抗氧化活性或与对细胞内抗氧化水平的调节有关(Krinsky，1990)。对于类胡萝卜素清除脂类过氧化物自由基的能力和作用机理已经进行了详细的研究(Burton et al.，1984; Burton, 1989; Terao，1989; Palozza et al.，1992b; Tsuchihashi et al.，1995)，但对于类胡萝卜素清除超氧阴离子自由基的能力尚未见有详细研究报道。本文以邻苯三酚自氧化体系作为超氧自由基的发生体系，对海藻中分离纯化制备的类胡萝卜素清除该种自由基的能力进行了初步的探讨。  相似文献