Marine Phytoplankton of the Welsh Coasts, With Special Reference to the Vicinity of Aberystwyth

Abstract

IN the course of work done on the marine phytoplankton of the Welsh coasts, attention was paid more especially to the area in the vicinity of Aberystwyth. For purposes of comparison, visits were also made to, and samples obtained from, other parts of the Welsh coasts. As the work done was carried on from a land station, it was found that a study of the free-floating plant organisms as such tended to include also those forms which are not, strictly speaking, planktonic, but which occur as regular components of the plankton flora wherever coastal influences are in evidence. As compared with the open ocean, the distinguishing feature of such offshore or neritic areas is the considerably greater variation in hydrographic conditions, this in turn making for a correspondingly wider range of variation in the plankton organisms themselves. For such a specialised coastal community various terms have been proposed; Haeckel names it the meroplankton as distinct from the holoplanktonic or holopelagic ecological unit of the open sea'. Schimper's term hemiplankton connotes much the same plankton-association of the coast-line. Kolkwitz2 advocates the use of the term seston, but, including