. 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. Oceanography. PELAGIC PLANT LIFE 33, usually almost globular development-stages that live in symbiosis with various animals, and, in particular, with radiolaria. Of these radiolaria, which would seem from Brandt's investigations Brandt. to derive special benefit from the assimilation-products of algae, we occasionally get the colony-forming species and Acantho- metridae in such myriads among the surface-layers
. 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. Oceanography. PELAGIC PLANT LIFE 33, usually almost globular development-stages that live in symbiosis with various animals, and, in particular, with radiolaria. Of these radiolaria, which would seem from Brandt's investigations Brandt. to derive special benefit from the assimilation-products of algae, we occasionally get the colony-forming species and Acantho- metridae in such myriads among the surface-layers, that they contribute a very large proportion of the organic substance produced. I have previously stated that the brown algae also regularly associate with a whole series of Dinophysidae. Another family of brown flagellates includes the species of Phceocystis, which form large colonies visible to the naked eye, and enveloped in a loose slime (see Fig. 240). In cold waters these have actually been known to occur in sufficient numbers to stop up the meshes of silk nets, and render them ineffec- tive in It is the brown algae that, properly speaking, characterise the plant-world of the sea. Still there are two other important series, the cyanophyceae and the chloro- phyceae, which preponderate in fresh water, and are, no doubt, re- presented in salt water also, though by only a few species. The Cyanophyceae are chiefly Cyanophycese. to be met with in warmer seas, if we except the brackish water forms that may be found along the coasts of North Europe in the height of the summer. The genus Trichodesmium appears as clusters of threads, composed of Tnchodes- brownish-yellow or red cells, which are either parallel to one n another, or twisted together, or matted and tangled, and radiating in all directions. Wille, who described these forms wme. collected by the German Plankton Expedition in i88q, showed. Fig. 240. -Phjeocystis poucheti. (Lagerheim.) that all the types may b
Size: 1425px × 1753px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublisherlondo, bookyear1912
