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  • Cyclic hematopoiesis  (1)
  • Global Environmental Change: The Northern North Atlantic; Jan-Mayen Current; MOOR; Mooring; OG4; OG5; SFB313; SFB313Moorings; Silicon Cycling in the World Ocean; SINOPS  (1)
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  • 1
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    Unknown
    Flux data in the Greenland Basin
    PANGAEA
    In:  Supplement to: von Bodungen, Bodo; Antia, Avan N; Bauerfeind, Eduard; Haupt, Olaf; Koeve, Wolfgang; Machado, E; Peeken, Ilka; Peinert, Rolf; Reitmeier, Sven; Thomsen, C; Voss, Maren; Wunsch, M; Zeller, Ute; Zeitzschel, Bernt (1995): Pelagic processes and vertical flux of particles: an overview of a long-term comparative study in the Norwegian Sea and Greenland Sea. Geologische Rundschau, 84(1), 11-27, https://doi.org/10.1007/BF00192239
    Details
    Publication Date: 2023-05-12
    Description: Pelagic processes and their relation to vertical flux have been studied in the Norwegian and Greenland Seas since 1986. Results of long-term sediment trap deployments and adjoining process studies are presented, and the underlying methodological and conceptional background is discussed. Recent extension of these investigations at the Barents Sea continental slope are also presented. With similar conditions of input irradiation and nutrient conditions, the Norwegian and Greenland Seas exhibit comparable mean annual rates of new and total production. Major differences can be found between these regions, however, in the hydrographic conditions constraining primary production and in the composition and seasonal development of the plankton. This is reflected in differences in the temporal patterns of vertical particle flux in relation to new production in the euphotic zone, the composition of particles exported and in different processes leading to their modification in the mid-water layers. In the Norwegian Sea heavy grazing pressure during early spring retards the accumulation of phytoplankton stocks and thus a mass sedimentation of diatoms that is often associated with spring blooms. This, in conjunction with the further seasonal development of zooplankton populations, serves to delay the annual peak in sedimentation to summer or autumn. Carbonate sedimentation in the Norwegian Sea, however, is significantly higher than in the Greenland Sea, where physical factors exert a greater control on phytoplankton development and the sedimentation of opal is of greater importance. In addition to these comparative long-term studies a case study has been carried out at the continental slope of the Barents Sea, where an emphasis was laid on the influence of resuspension and across-slope lateral transport with an analysis of suspended and sedimented material.
    Keywords: Global Environmental Change: The Northern North Atlantic; Jan-Mayen Current; MOOR; Mooring; OG4; OG5; SFB313; SFB313Moorings; Silicon Cycling in the World Ocean; SINOPS
    Type: Dataset
    Format: application/zip, 2 datasets
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 2
    Electronic Resource
    Electronic Resource
    Ultrastructural changes of bone marrow in canine cyclic hematopoiesis (CH dog) (1981)
    Springer
    Virchows Archiv 390 (1981), S. 93-108 
    Details
    ISSN: 1432-2307
    Keywords: Cyclic hematopoiesis ; Bone marrow ; Ultrastructure ; Nuclearcytoplasmic asynchrony ; Döhle-like bodies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The pathogenesis of cyclic hematopoiesis (CH) in the grey collie dog is still unknown. It has been proposed that periodic bursts of necrosis of the bone marrow neutrophils would induce cyclic arrests of the stem cell differentiation. In the present study, the sequential changes undergone by the erythroid and neutrophil series of the bone marrow of CH dogs were evaluated by electron microscopy. Erythroid cells presented quantitative periodic oscillations but the morphologic features of both immature and mature cells were normal. On the contrary, nonspecific necrotic changes were observed to occur in the myeloid series. Those abnormalities, which were more marked between days 9 and 11 of the cycle, mainly involved the immature cells and, to a lesser extent, the mature neutrophils. The number of necrotic cells was variable in different cycles, but always represented a small portion of the myeloid cells. In addition, few bone marrow macrophages displayed signs of phagocytic activity containing cell debris. The ultrastructural changes of the myeloid series were accompanied by an abnormal decrease of peroxidase activity and the permanence of large acid phosphatase-positive Golgi complexes in mature neutrophils, as defined by morphologic criteria. Döhle-like arrays of rough endoplasmic reticulum were present in many cells. Our findings suggest that an asynchronic development of myelocytes occurs as a result of regulatory abnormalities related to the congenital defect of the bone marrow which interferes with the differentiation and maturation of the stem cells. Necrosis in some myeloid cells would be a secondary phenomenon rather than a causal factor for the cyclic arrest of cell maturation as has been previously submitted. Furthermore, the small size of the necrotic cell population could not justify the production of “inhibitors” in sufficient amounts as to block the normal evolution of the bone marrow stem cell pool.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00443900
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    Paper (German National Licenses)
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