Factors affecting marine debris deposition at French Frigate Shoals, Northwestern Hawaiian Islands Marine National Monument, 1990-2006   总被引：1，自引：0，他引：1  

Morishige C  Donohue MJ  Flint E  Swenson C  Woolaway C 《Marine pollution bulletin》2007,54(8):1162-1169

Data on the amount and type of small debris items deposited on the beaches of the Hawaiian Islands National Wildlife Refuge Tern Island station, French Frigate Shoals were collected over 16 years. We calculated deposition rates and investigated the relationship among deposition and year, season, El Ni?o and La Ni?a events from 1990 to 2006. In total 52,442 debris items were collected with plastic comprising 71% of all items collected. Annual debris deposition varied significantly (range 1116-5195 items) but was not influenced by season. Debris deposition was significantly greater during El Ni?o events as compared to La Ni?a events. Although often deduced to influence floating marine pollution, this study provides the first quantitative evidence of the influence of El Ni?o/La Ni?a cycles on marine debris deposition.  相似文献   

Origin,evolution and anatomy of silt‐prone submarine external levées     

Emma A. Morris  David M. Hodgson  Rufus L. Brunt  Stephen S. Flint 《Sedimentology》2014,61(6):1734-1763

Submarine external levées are constructional features that develop outside slope channel systems, and are a volumetrically significant component of continental margins. However, detailed observations of their process sedimentology and depositional architecture are rare. Extensive exposures of external levées at multiple stratigraphic intervals and well‐constrained palaeogeographic positions in the Fort Brown Formation, Karoo Basin, South Africa, have been calibrated with research boreholes. This integrated data set permits their origin, evolution and anatomy to be considered, including high‐resolution analysis of sedimentary facies distribution and characterization of depositional sub‐environments. An idealized model of the stratigraphic evolution and depositional architecture of external levées is presented, and variations can be attributed to allogenic (for example, sediment supply) and autogenic (for example, channel migration) factors. Initiation of external levée construction is commonly marked by deposition of a basal sand‐rich facies with sedimentary structures indicating rapid deposition from unconfined flows. These deposits are interpreted as frontal lobes. Propagation of the parent channel, and resultant flow confinement, lead to partial erosion of the frontal lobe and development of constructional relief (levées) by flow overspill and flow stripping. Overall fining‐upwards and thinning‐upwards profiles reflect increased flow confinement and/or waning flow magnitude through time. Identification of a hierarchy of levée elements is not possible due to the absence of internal bounding surfaces or sharp facies changes. The down‐slope taper in levée height and increasing channel sinuosity results in increasing numbers of crevasse lobe deposits, and is reflected by the increased occurrences of channel avulsion events down‐dip. External levées from the Fort Brown Formation are silt‐rich; however their stratigraphic evolution and the distribution of many components (such as sediment waves and crevasse lobe) share commonalities with mud‐rich external levées. This unique integrated data set has permitted the first high‐resolution characterization of external submarine levée systems.  相似文献   

Bloom of Euglena sp. (Euglenophyceae,Euglenales) in the Outer Part of the Ob River Estuary     

Sukhanova  I. N.  Flint  M. V. 《Oceanology》2022,62(4):510-516

Oceanology - The material was obtained on July 18–24, 2016 in the area comprising the Ob River estuary and the adjacent shelf of the Kara Sea (71°28.3′–74°38.8′...  相似文献   

The Missing Intermediate Luminosity Galaxies in the Leo I Group     

K. Flint  M. Bolte  C. Mendes de Oliveira 《Astrophysics and Space Science》2003,285(1):191-195

We present results from a large scale R-band survey of the nearby Leo I group to measure the luminosity function down to dwarf spheroidal luminosities and surface brightnesses. This program has utilized>7 square degrees of imaging with the Mosaic camera at the KPNO 0.9mand extensive, on-going spectroscopic follow-up. We estimate our completeness from simulations to be 90% at μ_R(0) ≃ 24.5, M _R ≃ –11.Leo I is a nearby, low-density group for which a steep faint-end slope has been suggested (Ferguson and Sandage, 1991).We find the luminosity function to be more similar to that of the Local Group at the faint-end (flat).We also find an unusual gap in the luminosity function at intermediate luminosities, –19.5 < M _R < –16. This gap cannot be explained by pure Poisson fluctuations around a typical Schechter function, nor is it likely to result from photometric incompleteness. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Structural Evidence of Recent Activity of the Khatanga–Lomonosov Fault Zone in the Laptev Sea     

Baranov  B. V.  Flint  M. V.  Rimskiy-Korsakov  N. A.  Poyarkov  S. G.  Dozorova  K. A. 《Doklady Earth Sciences》2018,480(1):671-673

Doklady Earth Sciences - New structural data obtained by a geophysical survey during Cruise 69 of the R/V Akademik Mstislav Keldysh in 2017 indicate that the Khatanga−Lomonosov fault zone is...  相似文献   

Changes in the Radiation State of Bottom Sediments in Yenisei Gulf     

Miroshnikov  A. Yu.  Flint  M. V.  Dubinina  E. O.  Asadulin  En. E.  Shchuka  S. A.  Usacheva  A. A. 《Doklady Earth Sciences》2018,483(2):1582-1586

Doklady Earth Sciences - This paper reports on the results of radiation monitoring of bottom sediments in Yenisei Gulf for the period from 1995 to 2016. Clear positive trends in changing the...  相似文献   

Lateral variability in clinoform trajectory,process regime,and sediment dispersal patterns beyond the shelf‐edge rollover in exhumed basin margin‐scale clinothems          下载免费PDF全文

George E. D. Jones  David M. Hodgson  Stephen S. Flint 《Basin Research》2015,27(6):657-680

Sediment supply rate and accommodation regime represent primary controls on the depositional architecture of basin margin successions, but their interaction is commonly inferred from 2D dip profiles and/or with limited constraints on sedimentary facies. In this study, three parallel (>40 km long) 2D depositional oblique‐dip profiles from outcrops of the lower Waterford Formation (Karoo Basin, South Africa) have been correlated. This data set provides a rare opportunity to assess the lateral variability in the sedimentary process record of the shelf‐to‐slope transition for eight successive clinothems over a 900 km² area. The three profiles show similar shelf‐edge rollover trajectories, but this belies significant along‐margin variability in sedimentary processes and down‐dip sediment supply. The depositional architecture of three successive clinothems (WfC 3, 4 and 5) also show along‐shelf physiographic differences. The reconstructed shelf‐edge rollover position is not straight, and a westward curve to the north coincides with an area of greater sand supply to the slope beyond a shelf dominated by wave and storm processes. All the clinothems thicken northwards, indicating an along‐margin long‐term increase in accommodation that was maintained through multiple shoreline transits across the shelf. The origin of the differential subsidence cannot be discriminated confidently between tectonic or compaction processes. The interplay of basin margin physiography, differential subsidence rate and process regime resulted in significant across‐strike variability in the style and timing of sediment dispersal patterns beyond the shelf‐edge rollover. This study highlights the challenge for accurate prediction of the sediment partitioning across the shelf‐edge rollover in subsurface studies.  相似文献   

The role of zooplankton in the transformation of the organic matter in the Ob estuary,on the shelf,and in the deep regions of the Kara Sea     

E. G. Arashkevich  M. V. Flint  A. B. Nikishina  A. F. Pasternak  A. G. Timonin  J. V. Vasilieva  S. A. Mosharov  K. A. Soloviev 《Oceanology》2010,50(5):780-792

The data for the present study were collected at 20 sampling stations in the Kara Sea along the transect from the Ob estuary to the deep sea St. Anna Trough in September 2007. Based on the hydrophysical features, the distribution of the Chl a, and the primary production, we distinguished six habitats: the river, estuary, inner and outer shelf, continental slope, and trough. The impact of the small-size (<0.5 mm) and large-size (>0.5 mm) fractions of the zooplankton on the phytoplankton’s organic carbon in the different regions of the Kara Sea was estimated. The ingestion rate was assessed using the analysis of the gut fluorescence content and the gut evacuation rate. The zooplankton grazed 1–2% of the phytoplankton biomass in the river and estuary; 3.5% over the shelf; and 6 and 10% in the regions of the trough and slope, respectively. The grazing impact of the small-sized zooplankton increased from the river zone to the deep regions (from 1 to 90%) along with their share in the total zooplankton abundance (from 18 to 95%). From 72 to 86% of the primary production was grazed over the shelf and slope. The primary production did not cover the feeding requirements of the zooplankton in the estuarine regions and St. Anna Trough in the autumn. In the estuarine regions, the major portion of the organic matter settles on the bottom due to the strong inflow of the allochthonous matter and the relatively low zooplankton grazing.  相似文献   

Ecosystems of Siberian Arctic Seas–2020: The Kara Sea (Cruise 81 of the R/V Akademik Mstislav Keldysh)     

Flint  M. V.  Poyarkov  S. G.  Rimsky-Korsakov  N. A.  Miroshnikov  A. Yu. 《Oceanology》2021,61(2):292-294

Cruise 81 of the R/V Akademik Mstislav Keldysh was organized by Shirshov Institute of Oceanology and took place from August 27 to September 25, 2020 under the Program “Marine Ecosystems of the Siberian Arctic.” Participants included 76 scientists from the institutes of Russian Academy of Sciences, Moscow State University, VNIRO, and the NRC Kurchatov Institute and specialists from the Emergency Situations Ministry. Coordinated hydrophysical, hydrochemical, biooceanological, geochemical, and radioecological research was carried out over the Kara Sea, on the shelf near the St. Anna Trough, the continental slope, the Novaya Zemlya depression, and bays of the eastern coast of Novaya Zemlya. The condition of disposed radioactive waste in bays of the archipelago was assessed.

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Anatomy, geometry and sequence stratigraphy of basin floor to slope turbidite systems, Tanqua Karoo, South Africa     

Stephen David Johnson  Stephen Flint  David Hinds  & H. De Ville Wickens 《Sedimentology》2001,48(5):987-1023

The Tanqua area of the Karoo basin, South Africa, contains five Permian deep-water turbidite fan systems, almost completely exposed over some 640 km². Reconstruction of the basin-fill and fan distributions indicates a progradational trend in the 450 m+ thick succession, from distal basin floor (fan 1) through basin-floor subenvironments (fans 2, 3 and 4) to a slope setting (fan 5). Fans are up to 65 m thick with gradational to sharp bases and tops. Facies associations include basin plain claystone and distal turbidite siltstone/claystone and a range of fine-grained sandstone associations, including low- and high-density turbidite current deposits and proportionally minor debris/slurry flows. Architectural elements include sheets of amalgamated and layered styles and channels of five types. Each fan is interpreted as a low-frequency lowstand systems tract with the shaly interfan intervals representing transgressive and highstand systems tracts. All fans show complex internal facies distributions but exhibit a high-frequency internal stratigraphy based on fan-wide zones of relative sediment starvation. These zones are interpreted as transgressive and highstand systems tracts of higher order sequences. Sandy packages between these fine-grained intervals are interpreted as high-frequency lowstand systems tracts and exhibit dominantly progradational stacking patterns, resulting in subtle downdip clinoform geometries. Bases of fans and intrafan packages are interpreted as low- and high-frequency sequence boundaries respectively. Facies juxtapositions across these sequence boundaries are variable and may be gradational, sharp or erosive. In all cases, criteria for a basinward shift of facies are met, but there is no standard 'motif' for sequence boundaries in this system. High-frequency sequences represent the dominant mechanism of active fan growth in the Tanqua deep-water system.  相似文献