Not logged in
PANGAEA.
Data Publisher for Earth & Environmental Science

Bjorklund, Kjell R; Ciesielski, Paul F (1994): Morphology of Cycladophora davisiana davisiana from the Atlantic Ocean [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.690418, Supplement to: Bjorklund, KR; Ciesielski, PF (1994): Ecology, morphology, stratigraphy, and the paleoceanographic significance of Cycladophora davisiana davisiana. Part I: Ecology and morphology. Marine Micropaleontology, 24(1), 71-88, https://doi.org/10.1016/0377-8398(94)90012-4

Always quote citation above when using data! You can download the citation in several formats below.

RIS CitationBibTeX CitationShow MapGoogle Earth

Abstract:
In recent years, temporal fluctuations in the abundance of C. d. davisiana have been used frequently as a highresolution stratigraphic and paleoenvironmental tool. The modern ecology and morphologic variation (temporal and geographic) of this radiolarian species is evaluated to ascertain its potential stratigraphic and paleoenvironmental significance.
Statistics were obtained on the width and height of all C. d. davisiana segments from Pleistocene populations of differing ages from the Northern Hemisphere (Labrador Sea and Iceland-Faeroe Ridge) and Southern Hemisphere (Namibian shelf and Meteor Rise). Results reveal that segment height variations between and within populations are more conservative than segment width. The mean sizes of the thorax and first abdominal segment have distinguishable differences between C. d. davisiana found in the North and South Atlantic. All populations have no significant difference in first abdominal segment width, however, mean heights of this segment differ greatly between populations of the North and South Atlantic. Second abdominal segment sizes show no clear population grouping. Size differences in post-cephalic segment size of these populations would appear to be related to some isolation of gene pools and possibly unknown paleoenvironmental factors. Temporal changes in the postcephalic size of C. d. davisiana may be used to: (1) identify temporally equivalent peaks in abundance of the species in a given region, (2) possibly evaluate the degree of mixing of water'masses between regions, and (3) trace the initial spread of the species from its area of origin.
Cleve's 1887 plankton samples, between Greenland and Spitzsbergen, were studied and used in conjunction with other data to make the following conclusions on the modern ecology of C. d. davisiana in the Arctic and Greenland-Norwegian Seas. (1) It is presently absent in surface water plankton samples, (2) it currently lives at depths below 500 m, where it is rare, (3) it does not live in the upper 200 m under Arctic ice but is rare at greater depths, (4) it is absent in the upper 200 m near permanent Greenland Sea ice where normal oceanic salinity prevails, and (5) it is most common in deep marginal fjord environments which may serve as a refuge for the species during interglacial periods.
In the Atlantic Ocean, the abundance of C. d. davisiana does not exceed 1% of the assemblage between the Subtropical Convergence of each hemisphere. In the Norwegian and Labrador Seas the species may occasionally be in the range of 1-5% of the modern radiolarian assemblage and never more than 5% in the southern high latitudes. Apparently only in the modern Sea of Okhotsk, does the species presently occur in high abundance. We concur with Morley and Hays (1983) that increased abundances are likely caused by the development of a strong low-salinity surface layer associated with seasonal sea ice melting and a strong temperature minimum above warmer and higher salinity intermediate waters. Similar conditions were frequent during the Pleistocene in the high latitudes and its modern scarcity outside the Sea of Okhotsk must be related to the absence of the presently unique conditions in the latter region.
Project(s):
Deep Sea Drilling Project (DSDP)
Ocean Drilling Program (ODP)
Coverage:
Median Latitude: 16.708550 * Median Longitude: 13.011759 * South-bound Latitude: -46.879000 * West-bound Longitude: -48.369100 * North-bound Latitude: 78.966700 * East-bound Longitude: 102.850000
Date/Time Start: 1898-07-29T00:00:00 * Date/Time End: 1987-04-26T06:54:00
Event(s):
38-336 * Latitude: 63.351000 * Longitude: -7.787800 * Date/Time: 1974-08-07T00:00:00 * Elevation: -811.0 m * Penetration: 515 m * Recovery: 219.9 m * Location: North Atlantic/Norwegian Sea * Campaign: Leg38 * Basis: Glomar Challenger * Method/Device: Drilling/drill rig (DRILL) * Comment: 42 cores; 383.5 m cored; 19 m drilled; 57.3 % recovery
105-646B * Latitude: 58.209300 * Longitude: -48.369100 * Date/Time Start: 1985-10-04T08:45:00 * Date/Time End: 1985-10-13T21:01:00 * Elevation: -3459.0 m * Penetration: 766.7 m * Recovery: 404.25 m * Location: Labrador Sea * Campaign: Leg105 * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 80 cores; 766.2 m cored; 0 m drilled; 52.8 % recovery
114-704A * Latitude: -46.879000 * Longitude: 7.420800 * Date/Time Start: 1987-04-25T13:30:00 * Date/Time End: 1987-04-26T06:54:00 * Elevation: -2543.0 m * Penetration: 282.7 m * Recovery: 224.55 m * Location: South Atlantic Ocean * Campaign: Leg114 * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 30 cores; 282.7 m cored; 0 m drilled; 79.4 % recovery
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
6 datasets

Download Data

Download ZIP file containing all datasets as tab-delimited text — use the following character encoding:

Datasets listed in this publication series

  1. Bjorklund, KR; Ciesielski, PF (1994): (Table 1) Measurement of Cycladophora davisiana davisiana segments from DSDP Hole 38-336 on the northern flank of the Iceland-Faeroe Ridge. https://doi.org/10.1594/PANGAEA.690413
  2. Bjorklund, KR; Ciesielski, PF (1994): (Table 2, 3) Measurement of Cycladophora davisiana davisiana segments from ODP Hole 105-646B from the Labrador Sea. https://doi.org/10.1594/PANGAEA.690410
  3. Bjorklund, KR; Ciesielski, PF (1994): (Table 4) Measurement of Cycladophora davisiana davisiana segments from ODP Hole 114-704A in the southern South Atlantic. https://doi.org/10.1594/PANGAEA.690412
  4. Bjorklund, KR; Ciesielski, PF (1994): (Table 5) Measurement of Cycladophora davisiana davisiana segments from sediment core A3460 from the continental slope of Namibia. https://doi.org/10.1594/PANGAEA.690414
  5. Bjorklund, KR; Ciesielski, PF (1994): (Table 5) Measurement of Cycladophora davisiana davisiana segments from sediment core B3379 from the continental slope of Namibia. https://doi.org/10.1594/PANGAEA.690415
  6. Bjorklund, KR; Ciesielski, PF (1994): (Table 6, 7) Distribution of radiolarian species from the Cleve´s plankton stations between Greenland ans Spitsbergen. https://doi.org/10.1594/PANGAEA.690411