The plankton is divided into (a) the Zoo-plankton (such as the minute crustacea and the eggs and larva of fishes and many other marine animals); and (b) the Phyto-plankton, that is, the minute algae, diatoms, peridinians, some flagellate protozoa, spores of alga, etc. The investigation of the plankton from a new point of view, begun by Hansen in 1889, was continued by Lohmann at Kiel, by Cleve in Sweden, by Gran and Ostenfeldt in Norway and Denmark, and by Herdman, Allen and others in England.
In general the plankton - and especially the phyto-plankton of the polar and temperate seas - is much more abundant than is that of the sub-tropical and tropical zones.
This is mainly effected, in the sea, by the phyto-plankton.
Or March) and the days begin to lengthen the phyto-planktonic organisms begin to reproduce.
Therefore the animal organisms, as a rule, reproduce in the spring or early summer just after the vernal phyto-plankton maximum.
Following that again is a less well-marked maximum of phyto-plankton in the autumn, occurring just after the period of highest sea temperature.
Since there is less of the indispensable food material in the warmer seas there is, therefore, less phyto-plankton.
Plant albumins or phyto-albumins have been chiefly investigated in the case of those occurring in seeds; most are globulins,.
Other varieties or classes of these compounds are: plant caseins, phyto-vitellines, legumins and conglutins.
The German Plankton Expedition of 1889 added greatly to our knowledge of the floating vegetable life of the North Atlantic Ocean, while many laboratories established on the shores of inland seas and lakes have rendered a similar service in the case of our freshwater phyto-plankton.
They are those species which, on general phyto-geographical grounds, must be regarded as having originated under steppe-like conditions.