Archive image from page 370 of The depths of the ocean. The depths of the ocean : a general account of the modern science of oceanography based largely on the scientific researches of the Norwegian steamer Michael Sars in the North Atlantic depthsofoceangen00murr Year: 1912 PELAGIC PLANT LIFE 335 resting - cells. Halosphcsra occurs over the whole Atlantic Ocean, and follows the Gulf Stream to its farthest ramifica- tions in the north near the coasts of Norway and Spitzbergen. In the North Sea there are quantities, especially in the winter, and they form their zoospores in May, and thereby com
Archive image from page 370 of The depths of the ocean. The depths of the ocean : a general account of the modern science of oceanography based largely on the scientific researches of the Norwegian steamer Michael Sars in the North Atlantic depthsofoceangen00murr Year: 1912 PELAGIC PLANT LIFE 335 resting - cells. Halosphcsra occurs over the whole Atlantic Ocean, and follows the Gulf Stream to its farthest ramifica- tions in the north near the coasts of Norway and Spitzbergen. In the North Sea there are quantities, especially in the winter, and they form their zoospores in May, and thereby commence their new generation. Just as HalosphcEra differs from all the rest of the pelagic algae in having a pure green colour, so, too, it has its own special mode of reproduction. The other forms, whose development- history we know, are reproduced by division, and this goes on incessantly, the rate of increase depending upon different conditions of existence. Halosphcera does not undergo division, but continues to grow for a comparatively lengthy period, and then finally transforms all its contents, as has just been stated, into a great number of zoospores. In addition to Halosphcera viridis there are one or two similar species that have been described, but they do not call for any particular discussion. In the foregoing I have sketched the most important types of pelagic algae and their biology, but the picture Fig. 2ifi.—HALospHMRA VIRIDIS, would not be complete if I omitted to ™a1m?T''''''°''''''''''' describe the drifting species of sea- Floating sea- weed. These do not really belong '''• to the open sea. They grow along the coasts in the littoral zone, and their gas - filled bladders assist them in main- taining their position whatever be the state of the tide. The violence of the waves finally tears them loose, and then these same gas-bladders keep them for a long time floating on the surface. These patches of-- seaweed are to be met with in every coastal sea, the
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Keywords: 1900, 1910, 1912, _michael_sars_north_atlantic_deep_sea_expedition_191, appell_f_jakob_johan_adolf_1857_, archive, book, bookauthor, bookcentury, bookdecade, bookpublisher, booksubject, bookyear, drawing, gran_h_h_haakon_hasberg_1870_, helland_hansen_bj_rn_1877_, historical, history, illustration, image, london_macmillan, murray_john_sir_1841_1914, north_atlantic_ocean, oceanography, page, picture, print, reference, vintage
