. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. 84 DISCOVERY REPORTS sideration of the actual analyses, as it is evident that the observations were not sufficiently numerous to yield results of much value from the latter method of treatment. From the account already given it will have been seen that the characteristic Rhizosolenia plankton in the sub-Antarctic surface water, which had been such a feature of the first week in March of the previous year, and of which traces were still observed as late as April, did not occur in 1931, the phytop
. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. 84 DISCOVERY REPORTS sideration of the actual analyses, as it is evident that the observations were not sufficiently numerous to yield results of much value from the latter method of treatment. From the account already given it will have been seen that the characteristic Rhizosolenia plankton in the sub-Antarctic surface water, which had been such a feature of the first week in March of the previous year, and of which traces were still observed as late as April, did not occur in 1931, the phytoplankton at the comparatively few stations worked within the sub-Antarctic Zone on this occasion consisting mainly of Antarctic stragglers. On the other hand, while in 1930 the comparatively rich phytoplankton with small Chaetocerids and Nitzschia seriata dominant was not encountered until April, and then on the westernmost line, in 1931 a similar phytoplankton was encountered already half- way across the Scotia Sea early in March. In Fig. 39 the phytoplankton totals are. Fig. 40. The distribution of Corethron valdiviae (spineless chain form) in the Scotia Sea, February-March 1931. indicated by shading, and the presence of this comparatively rich phytoplankton to the south of the Antarctic convergence is clearly shown. The distributions of the more im- portant species of diatom have also been plotted individually in Figs. 40-45. Fig. 40 shows the distribution of the spineless chain form of Corethron valdiviae, which as we have endeavoured to show in the preceding pages, may be regarded as a dominant form of the phytoplankton in the southern sub-Antarctic waters, and also in old Antarctic water, in abnormally warm seasons, in late summer. This is well borne out by the dis- tribution observed during this particular piece of work. It will be seen that it occurred at five out of the six comparatively poor stations worked to the north of the con- vergence, and at four only of the sta
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