MICROPLANKTON 26 5 



Stephanophyxis turris was here an inshore ('coastal' or 'neritic') species found mainly in the northern (warmer) 



part of the area surveyed. Much more abundant in autumn than during spring. 



Thalassiosira subtilis had a panthalassic distribution. Maximal abundance inshore in autumn; greatest relative 



importance offshore during the spring survey. 



Planktoniella sol. An oceanic species relatively important at sparsely populated offshore stations only, during 



both surveys. 



Biddulphia longicruris. An inshore species frequent and 'typical' though never abundant, in spring samples; not 

 yet observed at all in autumn ones at the dilutions necessary to obtain counts. 



Eucampia zoodiacus. An inshore species with precisely the converse of the seasonal distribution of Biddulphia 

 longicruris. Eucampia zoodiacus was not seen at all during analysis of the spring samples. In autumn it was abundant, 

 sometimes one of the dominant species close inshore. 



Chaetoceros atlanticum (type) mainly offshore with pronounced spring maximum. 



Chaetoceros atlanticum var. neapolitanum even more definitely restricted to offshore waters than the type (with 

 relatively high temperature) but also in some of the same samples. 



Chaetoceros affine (syn. C. Ralfsii) here a strongly neritic species much more abundant in autumn than during spring. 



Chaetoceros compressum was one of the most abundant species at both seasons inshore, but sufficiently panthalassic 

 for the 'overspill' to dominate at a few of the sparser offshore catches as well. 



Chaetoceros constrictum. Very important during both surveys. Distributed much like C. compressum. 



Chaetoceros convolutum was mainly an offshore species most abundant during spring. 



Chaetoceros costatum, an inshore species most numerous in autumn (or late in the succession). 

 ' Chaetoceros curvisetum, mainly inshore and with a spring maximum, but very important at both seasons. The 

 most abundant species in these samples. Showed sufficient panthalassic tendency to dominate some offshore 

 samples as well, like C. compressum and C. constrictum, which often occurred with it. 



Chaetoceros debile. Inshore, most in autumn, very local here. 



Chaetoceros decipiens. Panthalassic, though mainly offshore here, more in spring than in autumn. 



Chaetoceros didymum. An inshore species with pronounced autumnal maximum, when the resting spores were 

 even more abundant than the vegetative phase. 



Chaetoceros difficile. Mainly inshore with autumn maximum. 



Chaetoceros laciniosum. An inshore species, local here, with strong spring maximum. 



Chaetoceros lorenzianum. Panthalassic here with spring maximum far offshore at the outer end of the Orange 

 river line. 



Chaetoceros peruvianum. Offshore form more abundant during spring than in autumn. 



Chaetoceros pseudocrinitum. An inshore or shelf species here, most in autumn. 



Chaetoceros sociale. A panthalassic species on its showing here, abundant at some very localized inshore stations, 

 but relatively more important offshore in spring. 



Chaetoceros strictum. An inshore species observed most abundantly during the spring survey. 



Chaetoceros subsecundum. An inshore species with autumn maximum, when many of the characteristic resting 

 spores were present. 



Chaetoceros teres. An inshore species most abundant in autumn here. 



Chaetoceros tetras. A very local species abundant at a few inshore stations, most in spring. 



Chaetoceros van heurckii. An inshore species most abundant in autumn. 



Rhizosolenia alata. Panthalassic rather than exclusively oceanic here, most important offshore in spring, but 

 numerous during both surveys. 



Rhizosolenia hebetata. Present here almost exclusively in the form (or phase) semispina. Was most numerous 

 inshore in spring, but of much greater relative importance offshore, especially in autumn. Panthalassic seems a 

 fairer description than oceanic for this extremely cosmopolitan form. 



Rhizosolenia imbricata. Here var. Shrubsolei was more frequent than the type, but both were present in the same 

 samples at times. Panthalassic, reaching its greatest relative importance offshore at both seasons. 



Rhizosolenia setigera. An inshore form with spring maximum. 



Rhizosolenia styliformis. Panthalassic, but mainly offshore with a pronounced spring maximum. 



Leptocylindrus danicus. An inshore species most abundant in autumn. 



Dactyliosolen mediterraneus. Panthalassic, maximum inshore in autumn, but offshore during the spring survey!? 

 Stenothermal. 



