GEOGRAPHIC DISTRIBUTION OF THE SPECIES
(Figures 8-229)

This section consists of maps depicting the geographic distribution of the species. Of the 307 radiolarian taxa covered in this survey, 222 are included in these maps (asterisked in Appendix 2).

Three levels of detail are used depending on the amount and type of distributional information available:

1. For the most abundant taxa (94 radiolarians; Figures 8-101–click on menu at left) data are presented separately for the upper 150 m of the water-column (plankton samples), for depths below 150 m (plankton and sediment trap samples), and for the sediments. The plankton tows included in each category were recorded as the mid-depth of the layer sampled. Thus, a few of the samples included in the 0 to150 m category actually collected materials from depths deeper than 150 m, while some of those included in the >150 m group sampled shallower layers. The map data are plotted in these categories: (a) relative abundance (percentage of the overall polycystine assemblage) in 6 classes (<0.5 to >10%), (b) "present" - where the species was recorded but not quantified, and (c) "absent" - where it was not recorded but had positive records in other samples from the same survey.

2. For the less abundant forms (128 species; Figures 102-229–click on menu at left) a single map for each species is given. In this case, depending on the numbers of datapoints available, maps show either absences, presences, and percentages (4 classes) for water-column and sedimentary materials separately, or positive records only (in the water-column and in the sediments separately).

In all cases original percentage data were pooled or averaged in 5 x 5 degree Marsden squares. For maps where water-column and sedimentary records are graphed separately, symbols are located in the middle of each Marsden square. For those where all available data are represented on a single map, to avoid overlaps symbols are slightly offset from the center of the square (position of symbols that fall on land has not been corrected).

N-values at the top of the maps indicate total number of positive records (first number), and total number of samples where the species was presumably sought (that is, samples forming part of data sets where the species was recoded at least once; second number, in square brackets).

Shadings are intended to serve as an aid for fast visual identification of the general area where the species was recorded, rather than denoting its distribution range. Shadings have not been extrapolated on the basis of the distribution of oceanographic parameters (currents, temperature, salinity, etc.). Negative records are usually outside of the shaded areas, except when densely surrounded by positive records.

Empty circles, indicating absence of the corresponding species, should not necessarily be interpreted as indicative of areas beyond the distribution range of the species; however, they do provide a general idea of the area where the species is at least scarcer.

No maps are given for the very scarce species, as well as for some poorly defined morphotypes for which the distributional information is quite likely inconsistent because of disagreements in their nomeclature and taxonomy.

Maps are arranged alphabetically within the two abundance categories defined above: first the 94 abundant taxa and then the 128 less abundant ones.

NOTE: Please see sidebar for alphabetical list of geographic distribution of species.