Investigating the use of proxies for fecundity to improve management advice for western horse mackerel Trachurus trachurus     

De Oliveira  J.A.A.; Roel  B.A.; Dickey-Collas  M. 《ICES Journal of Marine Science》2006,63(1):25-35

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Local remineralization patterns in the mesopelagic zone of the Eastern North Atlantic, off the NW Iberian Peninsula     

C.G. Castro  M. Nieto-Cid  X.A. lvarez-Salgado  F.F. Prez 《Deep Sea Research Part I: Oceanographic Research Papers》2006,53(12):1925-1940

The short-time-scale variability of the remineralization patterns in the domain of Eastern North Atlantic Central Waters (ENACW) off the NW Iberian Peninsula is studied based on biogeochemical data (oxygen, nutrient salts, total alkalinity, pH, dissolved organic matter and fluorescence of dissolved humic substances) collected weekly between May 2001 and April 2002. The temporal variability of inorganic variables points to an intensification of remineralization during the summer and autumn, with an increase of nutrients, total inorganic carbon and fluorescence and a decrease of oxygen. During the subsequent winter mixing, there is a biogeochemical reset of the system, with lower nutrients, total inorganic carbon and fluorescence and higher oxygen. In contrast to inorganic variables, the levels of dissolved organic matter in the ENACW seem to respond to short-term events probably associated with fast sinking particles, where solubilisation of organic matter prevails over remineralization. Applying a previously published stoichiometric model, we observed a vertical fractionation of organic-matter remineralization. Although there is a preferential remineralization of proteins and P compounds in the entire domain of ENACW, the percentage was higher in the upper ENACW (σ<27.10 kg/m³) than in the lower; the percentage of N and P compounds in the oxidised organic matter was >80% for the upper ENACW and 63% for the lower. Likewise, the redissolution of calcareous structures contributes about 6% and 13% to the carbon regenerated in the upper and lower layers of ENACW, respectively.  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   

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

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Effect of turbulence on feeding of larval fishes: a sensitivity analysis using an individual-based model   总被引：3，自引：1，他引：3  

Megrey  Bernard A.; Hinckley  Sarah 《ICES Journal of Marine Science》2001,58(5):1015-1029

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Book review     

Keith A. Kvenvolden 《Marine Geophysical Researches》1993,15(3):241-241

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Atlantic salmon ranching: past problems and future management     

Isaksson  A.; Oskarsson  S.; Einarsson  S. M.; Jonasson  J. 《ICES Journal of Marine Science》1997,54(6):1188-1199

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Environmental overview of Eckernförde Bay,northern Germany     

T. H. Orsi  F. Werner  D. Milkert  A. L. Anderson  W. R. Bryant 《Geo-Marine Letters》1996,16(3):140-147

This environmental overview of Eckernförde Bay (northern Germany) summarizes the results of previous studies relevant to the Office of Naval Research's Coastal Benthic Boundary Layer (CBBL) Baltic field exercise conducted during 1993–1994. Significant environmental characteristics include the following: (1) surface sediment distribution is related to water depth, dictated primarily by hydrodynamic reworking of older glacial deposits; (2) the origin and characteristics of small-scale sedimentary structures depend on storm-generated waves and currents; (3) the proximity of the sea surface and sediment —water interface results in a pelagic—benthic coupling that drives biogeochemical processes and produces organicrich, acoustically turbid sediments; and (4) the bay floor is complicated topographically by pockmarks and manmade sedimentary structures.  相似文献   

Multiple sound scattering by densely packed shoals of marine animals     

Andreeva  I. B.; Belousov  A. V. 《ICES Journal of Marine Science》1996,53(2):323-327

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