Deep-Sea Research, Part A: Oceanographic Research Papers

Gymnodinium sanguineum dinoflagellate cultures were subjected to constant staining flows to quantify the threshold level for growth inhibition by viscous streses for this organisms and to compare its response to that of a red tide species Gonyaulax polyedra previously studied. Growth inhibition of Gymnodinium was detected at rates-of-strain γ as small as 1 rad s−1 and was independent of γ in the range 1–40 rad s−1. Growth was delayed for 2–5 days, but not prevented entirely. For Gonyaulax, growth inhibition began for γ ≈ 3 rad s−, and growth was prevented entirely above 8 rads s−1. The fishery implication is that the apparent necessity of calm seas (Lasker Events) for the growth of larval northern anchovies may not be due to turbulence inhibition of their Gymnodinium food supply.

W.H. Thomas

C.H. Gibson

Deep Sea Research Part A Oceanographic Research Papers

Effects of quantified small-scale turbulence on the dinoflagellate, Gymnodium sanguineum (splendens): contrasts with Gonyaulax (Lingulodinium) polyedra, and the fishery implication

定量小尺度湍流对腰鞭毛虫赤潮藻（Gymnodium sanguineum (splendens)）的影响：与多边膝沟藻（Gonyaulax (Lingulodinium) polyedra）的对比及其渔业意义

J.R. Luyten

W.J. Schmitz

Henry Melson Stommel

亨利·梅尔森·斯托梅尔

Measurements of chemical tracers obtained during the 1987 cruise of F.S. Polarstern across the Nansen Basin of the Arctic Ocean are used to suggest the general flow of upper waters in the Arctic Ocean. In surface water, total carbonate concentrations distinguish between a northern freshwater component whose origin is river run-off and a southern freshwater component whose origin is sea ice meltwater. Below the surface layer, sub-surface water formed in the Barents-Kara Seas with low concentrations of "NO" must divide, some flowing with the Atlantic layer to the east and north before flowing in the same direction as the Transpolar Drift to Fram Strait, and some flowing to the west and south. The former characterizes the lower halocline water observed at the CESAR and LOREX ice camps in the central Arctic Ocean. The latter can be traced in a general way to Fram Strait where the two meet and the two low NO waters merge.

Leif G. Anderson

E. Peter Jones

Tracing upper waters of the Nansen Basin in the Arctic Ocean

追踪北极洋南森盆地上层水

Abstract In this paper we present the first data set for rare earth elements (REE) in the Arctic Ocean. The data are from unfiltered samples. The concentrations are La: 18.8–41.3 pM; Ce: 5.7–25; Pr: 1.4–9.9; Nd: 14.6–39.6; Sm: 2.7–7.3; Gd: 3.8–13.4; Dy: 3.7–12.3; Er: 3.6–9.6; and Yb: 2.9–8.1. The concentrations found in the deep water are lower than deep-water concentrations found elsewhere and are oceanographically consistent. Our data show that the distribution of REE are influenced by riverine input in the northern part of the investigated area. Transport of resuspended material into the water from the Barents Sea Shelf is suggested to influence the concentrations of REE in the southern part of the Nansen Basin. The covariation between REE and nutrients is opposite to that found in other oceans. The fresh water end member concentrations for the REE in the northern surface water have been calculated.

Stig Westerlund

Peder Öhman

Rare earth elements in the Arctic Ocean

北极海洋中的稀土元素

Planktonic foraminifera were collected in the Arctic Ocean with net tows (>63 μin) along a S-N transect from 81 to 86°N. Five depth intervals were sampled vertically between 500 m water depth and the sea surface. The most common species are Neogloboquadrina pachyderma and Globigerina quinqueloba. Based on the depth habitat, the faunal composition and the population structure, the planktonic foraminifera can be divided into two distinct provinces having a latitudinal boundary at 83°N. In the southern area, the concentrations of planktonic foraminifera are highest as well as the per cent of subpolar species and right-coiling individuals. Both species prefer the water below the pycnocline at about 100 m. North of 83°N, the two species display maximum abundance in the upper 50 m, where the water is colder and fresher than below the pycnocline. The proportions of right-coiling individuals and subpolar species are decreasing going northward. The observed changes are caused by the input of Atlantic water masses transported into the Arctic Ocean.

JÖrn Carstens

Gerold Wefer

Recent distribution of planktonic foraminifera in the Nansen Basin, Arctic Ocean

北极洋南森海盆浮游有孔虫近期分布

Sub-micrometer particles have recently been shown to exist in marine water at concentrations exceeding 107 particles ml−1. Their presence has important implications for ocean optics, global biogeochemical models and trophic relationships in the microbial food web. Small particles that were stainable by Acridine Orange (AO) and 4′,6-diamidino-2-phenylindole (DAPI) were enumerated and sized using a quantitative fluorescence microscopy imaging system along an onshore-offshore transect from the mouth of Chesapeake Bay to the Sargasso Sea. The particles were characterized by staining with DAPI, a stain specific for double-stranded DNA and generally indicative of a living cell or viral particle, and AO, a more general bio-polymer stain indicative of organic matter. Two distinct particle populations were measured in the 0.2–1.0 μm size range: (1) typical bacteria; and (2) abundant small, dimly fluorescing (SD) particles. Surface concentrations of organic (AO-staining), SD particles ranged from 3×107 ml−1 near the mouth of Chesapeake Bay to 4×106 ml−1 in the Sargasso Sea. A variable proportion of the SD particles were DAPI-positive, probably very small bacteria and viruses. The DAPI-positive SD particles constituted 9–29% of the total organic SD particles at coastal and shelf stations, and 25–61% in a vertical profile in oligotrophic waters. The vertical distribution of SD particles in oligotrophic waters showed higher numbers in the surface layer and lower numbers below the sub-surface chlorophyll maximum, suggesting an association of the particles with biological productivity. Our carbon estimates, based on measured particle size spectra and abundances, and reasonable values for particle carbon density, agree with recent measurements of bulk elemental particulate carbon in the 0.2–0.7 μm size fraction in the Sargasso Sea. The particle volume ml−1 of the total SD particles ranged from equal to twice the bacterial biovolume ml−1, indicating a significant carbon pool.

Michael E. Sieracki

Charles L. Viles

Distributions and fluorochrome-staining properties of submicrometer particles and bacteria in the North Atlantic

北冰洋亚微米颗粒和细菌的分布及荧光染色特性

By using a set-up that combines an integrating sphere with a spectroradiometer LI-1800 UW, the backscattering properties of nine different phytoplankters grown in culture have been determined experimentally for the wavelengths domain ν = 400 up to 850 nm. Simultaneously, the absorption and attenuation properties, as well as the size distribution function, have been measured. This set of measurements allowed the spectral values of refractive index, and subsequently the volume scattering functions (VSF) of the cells, to be derived, by operating a scattering model previously developed for spherical and homogeneous cells. The backscattering properties, measured within a restricted angular domain (approximately between 132 and 174°), have been compared to theoretical predictions. Although there appear some discrepancies between experimental and predicted values (probably due to experimental errors as well as deviations of actual cells from computational hypotheses), the overall agreement is good; in particular the observed interspecific variations of backscattering values, as well as the backscattering spectral variation typical of each species, are well accounted for by theory. Using the computed VSF, the measured backscattering properties can be converted (assuming spherical and homogeneous cells) into efficiency factors for backscattering (Qbb). Thhe spectral behavior of Qbb appears to be radically different from that for total scattering Qb. For small cells, Q (λ) is practically constant over the spectrum, whereas Qb(λ) varies approximately according to a power law (λ−2). As the cell size increases, Qbb conversely, becomes increasingly featured, whilst Qb becomes spectrally flat. The chlorophyll-specific backscattering coefficients (bb∗ appear highly variable and span nearly two orders of magnitude. The chlorophyll-specific absorption and scattering coefficients, a∗ and b∗, are mainly ruled by the interspecific variations in cellssize (D) and intracellular pigment concentration (Ci) (actually by the variations of the product DCi). Though bb∗ is involved in the modelling of the diffuse reflectance of waters, the impact of its actual variation is greatly limited because typical bb∗ values, even at their maximum (10−3 m2 mg−1), are very low. This result confirms that living algae have a negligible influence on the backscattering process by oceanic waters; other particles (bacteria, detritus, etc.) associated with algae are mainly responsible for this process.

Yu-Hwan Ahn

Annick Bricaud

André Morel

Light backscattering efficiency and related properties of some phytoplankters

一些浮游植物的光背散射效率及相关特性

We measured bacterial production and estimated the carbon consumption by bacteria in the mesopelagic zone (80–600 m) in the subarctic Pacific during May and August. Bacterial production was measured by leucine and thymidine incorporation. The two methods gave similar results. Bacterial production in the euphotic zone accounted for about 13% of primary production and in the whole water column for 20% (0–600 m). To bracket bacterial carbon consumption we made a lowest and highest estimate of bacterial production. The lowest estimate assumes zero isotope dilution for converting 14C-leucine incorporation rates into bacterial production and a 50% growth efficiency. In the mesopelagic zone, this estimate implies that bacterial account for 52 and 41% of the POC sinking flux as measured by sediment traps in May and August, respectively. The highest estimate, assuming two-fold isotope dilution of 14C-leucine and a 30% growth efficiency, yields bacterial carbon consumption values of 172 and 137% of the POC downward flux in both months. This indicates that bacteria are important, if not the major consumers of organic matter in the mesopelagic zone of the subarctic Pacific.

M. Simon

N.A. Welschmeyer

D.L. Kirchman

Bacterial production and the sinking flux of particulate organic matter in the subarctic Pacific

北太平洋副热带细菌生产和颗粒有机物沉降通量

In this study we investigate the utility of GEOSAT altimetry for monitoring the Iceland-Faeroe frontal zone. Since an expected dynamic topography relief of 10–20 cm over the Iceland-Faeroe Front (IFF) was not much above the 10 cm uncertainty in GEOSAT observations, validation by AVHRR imagery and satellite-tracked drifters constituted an important part of the experiment. Sea Surface Height (SSH) relief of greater than 20 cm occurred a long the western side of the IFF and along the eastern side, north of the Shetland Islands. However, with SSH relief of only 10–15 cm in the central region of the IFF, substantial difficulties were encountered in the ability to unambiguously monitor the location of the front. In contrast, frontal meanders with 20–30 cm SSH relief, current speeds up to 50 cm s−1 and radii of curvature of 25 km, were clearly observed on three occasions during the 2 year study. These meanders first appeared north of the Faeroe Islands, in the region from 6 to 8°W, and propagated southeastward at speeds of about 3.3 km day−1, being lost from view in the Faeroe-Shetland Channel. Their strong signals and lifetimes of 2–3 months would appear to make them important constituents of IFF dynamics.

Pavel Pistek

Donald R. Johnson

A study of the Iceland-Faeroe Front using GEOSAT altimetry and current-following drifters

利用GEOSAT测高和随流漂流浮标研究冰岛-法罗前缘

Previous work (by us and other) has shown that sediment trap fluxes do not correlate well with the total particulate mass concentration as determined with a transmissometer. Sediment traps are thought to collect the setting particles in the marine snow size range (d 〉 0.5mm). Cameras have been developed to quantitatively image particles in the marine snow size range but a correlation between measured flux in sediment traps and large-particle camera (LPC) profiles has not been established. In this study, LPC total particulate volume data are correlated with fluxes measured in sediment traps, indicating that sediment traps sample the large aggregate size range and that the flux is proportional to the concentration and size distribution of large aggregates. Partitioning of the major components of the bulk chemistry indicates that rebound aggregates (particles which do not undergo an appreciable change in their bulk chemistry before resuspension from the seafloor) contribute to aggregate nepheloid layers and increase measured trap fluxes. The bulk chemical composition of material from the deepest sediment traps indicates that downslope advection as well as cross-slope advection and subsequent settling may be amportant pathways for biogenic material to the deep ocean.

I.D. Walsh

W.D. Gardner

A comparison of aggregate profiles with sediment trap fluxes

沉积物捕集器通量与总粒径分布剖面的比较

Publication Information	Publisher: Pergamon Press Ltd.，Publishing cycle: ，Journal Type: journal，Open Access Journals: No
Basic data	Year of publication: 1979，Proportion of original research papers: ，Self Citation Rate:， Gold OA Rate:

Deep-Sea Research, Part A: Oceanographic Research Papers

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