The Vertical Distribution of Pelagic Decapods [Crustacea: Natantia] Collected on the Sond Cruise 1965 II. The Penaeidea and General Discussion

Author(s):  
P. Foxton

This paper represents the second and final part of a study of the depth distribution and diurnal migration of pelagic decapod crustaceans in an area of the eastern North Atlantic. Part I (Foxton, 1970) dealt with the Caridea; Part II now considers the Penaeidea. In the discussion the data as a whole are analysed and the resulting patterns of vertical distribution and migration discussed.

Author(s):  
P. Foxton

This study forms a contribution to a series (Angel, 1969; Clarke, 1969; Baker, 1970; Badcock, 1970) describing the biological results of a detailed investigation of the ecology of an oceanic area located in the eastern North Atlantic, close to the island of Fuerteventura (Canary Islands). The scientific background and objectives of the investigation, conducted during September to December 1965, have been described elsewhere (Currie, Boden & Kampa, 1969). Our main interest lay in the biological composition and acoustic characteristics of sonic scattering layers, and it was therefore considered essential to sample the principal elements of the pelagic fauna within the depth range 0–1000 m in as quantitative and detailed a manner as was technically possible. The resulting biological collections represent a unique body of material, the analysis of which is directly pertinent to the vertical distribution, diurnal migration and ecological interrelationships of the mesopelagic fauna.


Author(s):  
P. Foxton

SynopsisThe vertical distribution of pelagic decapods has been investigated at six positions, each located approximately at 10° interval of latitude between 11°N and 60°N in the eastern North Atlantic. An account of the day and night depth distribution of four mesopelagic species, Acanthephyra purpurea, A. pelagica, A. sexspinosa and A. acanthitelsonis, and four bathypelagic species, A. prionota, A. curtirostris, A. acutifrons and A. stylorostratis, is presented. The four mesopelagic species have vertical distributions which vary latitudinally in association with geographical gradients in temperature, the mesopelagic zone from about the latitude of 28°N cooling both polewards and equatorwards. It is concluded that environmental temperature is a major factor in controlling the vertical ranges of these species although other physical variables, principally light, must also be involved.A faunal boundary exists in the region of 18°N, where the North Atlantic species A. purpurea and A.pelagica are replaced by the Central and South Atlantic species A. sexspinosa and A. acanthitelsonis. The nature of the physical boundary is not clear, but it is tentatively proposed that it represents a relatively broad area where the North Atlantic Central Water and South Atlantic Central Water meet.


1988 ◽  
Vol 58 (2) ◽  
pp. 227-258 ◽  
Author(s):  
J. Bleeker ◽  
S. van der Spoel

The medusa fauna of the mid North Atlantic Ocean between 24° and 55°N along approximately 30°W is studied. Two Hydromedusae new to science, Oceania tydemani and Annatiara lempersi, are described. The differences in fauna south and north of 42°N, and faunal borders near 50°, 48°, 45°, 35°, 30°, and 34°-37° N are discussed. The vertical distribution and for some species the diurnal migration and subtropical submergence are recorded.


Author(s):  
Michael H. Thurston

INTRODUCTIONThis paper forms the second and last part of a study of the vertical distribution and migration of pelagic Amphipoda based on material collected off Fuertaventura, Canary Islands, during the SOND Cruise in 1965. The first part (Thurston, 1976b) dealt with the Gammaridea. The data presented herein deal with the Hyperiidea, to which is added a general discussion.The background to the cruise has been given by Currie, Boden & Kampa (1969), and Foxton (1969) has described the gear and methods used. This analysis is based primarily on samples obtained from a series of 1 m2 ring-net (N 113) hauls, but has been supplemented by selected materials from modified 3 m Isaacs-Kidd Mid-water Trawl (IKMT), neuston net and 1 m2 Rectangular Mid-water Trawl (RMT 1) hauls. Thurston (1976b) has discussed the limitations of the sampling techniques as they affect the present results.


1983 ◽  
Vol 40 (5) ◽  
pp. 637-643 ◽  
Author(s):  
C. W. Pugsley ◽  
H. B. N. Hynes

A freeze-coring device using liquid nitrogen is described, which enables one person to take a columnar core, extending from the surface to at least 50 cm below a stony streambed. An experiment to validate the technique showed that animals did not flee from the advance of the freezing-front. Using frozen streambed cores, the vertical distribution of benthic invertebrates of two streams in southern Ontario was investigated. In contrast to previous estimates,~70% of the fauna was found in the top 10 cm of the streambed, and invertebrate densities were often lower by an order of magnitude. These differences are attributed to problems of quantifying previous sampling methods.


2009 ◽  
Vol 6 (10) ◽  
pp. 2041-2061 ◽  
Author(s):  
Y. Ye ◽  
C. Völker ◽  
D. A. Wolf-Gladrow

Abstract. A one-dimensional model of Fe speciation and biogeochemistry, coupled with the General Ocean Turbulence Model (GOTM) and a NPZD-type ecosystem model, is applied for the Tropical Eastern North Atlantic Time-Series Observatory (TENATSO) site. Among diverse processes affecting Fe speciation, this study is focusing on investigating the role of dust particles in removing dissolved iron (DFe) by a more complex description of particle aggregation and sinking, and explaining the abundance of organic Fe-binding ligands by modelling their origin and fate. The vertical distribution of different particle classes in the model shows high sensitivity to changing aggregation rates. Using the aggregation rates from the sensitivity study in this work, modelled particle fluxes are close to observations, with dust particles dominating near the surface and aggregates deeper in the water column. POC export at 1000 m is a little higher than regional sediment trap measurements, suggesting further improvement of modelling particle aggregation, sinking or remineralisation. Modelled strong ligands have a high abundance near the surface and decline rapidly below the deep chlorophyll maximum, showing qualitative similarity to observations. Without production of strong ligands, phytoplankton concentration falls to 0 within the first 2 years in the model integration, caused by strong Fe-limitation. A nudging of total weak ligands towards a constant value is required for reproducing the observed nutrient-like profiles, assuming a decay time of 7 years for weak ligands. This indicates that weak ligands have a longer decay time and therefore cannot be modelled adequately in a one-dimensional model. The modelled DFe profile is strongly influenced by particle concentration and vertical distribution, because the most important removal of DFe in deeper waters is colloid formation and aggregation. Redissolution of particulate iron is required to reproduce an observed DFe profile at TENATSO site. Assuming colloidal iron is mainly composed of inorganic colloids, the modelled colloidal to soluble iron ratio is lower that observations, indicating the importance of organic colloids.


Biologia ◽  
2011 ◽  
Vol 66 (2) ◽  
Author(s):  
Evangelia Doulka ◽  
George Kehayias

AbstractThe investigation of the vertical distribution of the zooplankton community in the temperate Lake Trichonis during four seasons in 2005, showed the existence of vertical segregation among species, ontogenetic stages and sexes within and between the major groups. In each season, the two or three more abundant rotifer species distributed at separate depth layers, while this feature was maintained during the entire 24 h period, since no diel vertical migrations (DVM) were performed. In contrast, the crustacean community, comprised mainly by the calanoid copepod Eudiaptomus drieschi and the cladoceran Diaphanosoma orghidani, showed various patterns of DVM, being more pronounced in spring and summer. Females of E. drieschi distributed deeper than males, while the copepod nauplii were found mainly in the surface layer in all four seasons. Temperature was the most important abiotic factor affecting directly and indirectly the vertical distribution and migration of various species. During stratification, the metalimnion was the most productive layer in Lake Trichonis, having maximum values of dissolved oxygen and low transparency due to high concentration of organic matter and phytoplankton. The DVM patterns of the crustaceans indicate that the metalimnion acts probably as a daylight refuge against predation by Atherina boyeri, which is the dominant planktivorous fish in the lake.


Author(s):  
C. C. Lu ◽  
M. R. Clarke

Little work on vertical distribution of cephalopods was possible before the development, in the 1960s, of sophisticated opening-closing devices usable on midwater trawls such as the 10 ft Isaacs Kidd trawl (IKMT; Foxton, 1963; Aron et al. 1964) and the series of rectangular midwater trawls developed by the Institute of Oceanographic Sciences (previously the National Institute of Oceanography) (Clarke, 1969 a; Baker et al. 1973). These developments have resulted in three papers on vertical distribution of cephalopods in the North Atlantic (Clarke, 1969 ft; Gibbs & Roper, 1970; Clarke & Lu, 1974) and one for the Mediterranean (Roper, 1972). The present paper describes the vertical distribution of cephalopods caught at 40° N 20° W, 53° N 20° W and 60° N 20° W in the North Atlantic based upon day and night series of horizontal hauls between the surface and 2000 m using the RMT combination net (Baker et al. 1973).


2020 ◽  
Author(s):  
Andreas Petzold ◽  
Susanne Rohs ◽  
Mihal Rütimann ◽  
Patrick Neis ◽  
Berkes Florian ◽  
...  

<p>The vertical distribution and seasonal variation of water vapour volume mixing ratio (H<sub>2</sub>O VMR), relative humidity with respect to ice (RH<sub>ice</sub>) and particularly of regions with ice-supersaturated air masses (ISSR) in the extratropical upper troposphere and lowermost stratosphere are investigated at northern mid-latitudes over the regions Eastern North America, the North Atlantic and Europe for the period 1995 to 2010.</p><p>Observation data originate from regular and continuous long-term measurements of H<sub>2</sub>O VMR, temperature and RH<sub>ice</sub> by instrumented passenger aircraft in the framework of the European research program MOZAIC which is continued as European research infrastructure IAGOS (from 2011; see www.iagos.org). The observation data are analysed with respect to the thermal and dynamical tropopauses, as provided by ERA-Interim. Additionally, collocated O<sub>3</sub> observations from MOZAIC are used as tracer for stratospheric air masses.</p><p>Our key results provide in-depth insight into seasonal and regional variability and tropospheric nature of ice-supersaturated air masses at various distances from the tropopause layer. For the vertical distribution and seasonal variation of ISSR occurrence we show a comparison of our results to radio soundings and to satellite observations of cirrus cloud occurrence from AIRS and TOVs Path B instruments. Finally, for all three regions, we investigate the trends and the dependencies of ISSR occurrence on the North Atlantic Oscillation (NAO) index.</p>


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