PHYTOPLANKTON OF EAST CUMBERLAND BAY 213 



low. The wind on the previous day had been blowing hard from the west-north-west, 

 and it is possible that low salinity water had been driven out from the region of the 

 Neumayer glacier in West Fjord, over the top of the water of higher salinity present in 

 the deeper layers at both Sts. MS 98 and 97. At any rate it is obvious that the low 

 salinity surface water with high phosphate at St. MS 98 was of different origin from 

 that at the previous station, which contained less phosphate than any other sample 

 examined throughout the season. The sharp fall in surface sahnity at St. MS 97 was 

 consequent upon wild south-easterly weather during the preceding days, although the 

 wind on the morning of the station itself was northerly. Prior to this easterly period, 

 northerly winds had prevailed for a considerable time, culminating in the high salinity 

 values obtained at St. MS 95, when there was high phosphate and a marked invasion 

 of Coscinodiscus stellaris also. During this time the surface water piled up inshore would 

 undergo dilution by land drainage, and also tend to be deprived of its phosphate by the 

 kelp. This appears to be the probable explanation of the extremely low phosphate value 

 (for this area) of the surface water at St. MS 97, when this diluted water had been driven 

 out again by the south-easterly winds of the preceding four days. 



From Fig. 84 it appears that at St. MS 100, with northerly wind and rising phosphate, 

 there was still a fall in salinity at the surface. This was due to the melting of much 

 glacier ice which drifted past while the station was in progress, causing dilution of the 

 inflowing water comparatively rich in phosphate. 



It appears, then, to be generally true that dilution of the surface layers by land drainage 

 tends to reduce not only the salinity but the phosphate content also. This is precisely 

 the reverse of the suggestions of some plankton workers in the northern hemisphere 

 (cf. Gran, 1929). It must be remembered, however, that the initial phosphate value in the 

 upper layers in East Cumberland Bay {ca. 90 mg. P2O5 per m.* when these observations 

 were begun) is probably very much greater. The valuable detailed investigations of 

 Marshall and Orr (1927) in Loch Striven indicate <:«. 50 mg. P0O5 per m.^ as the maximum 

 ever attained in the upper layers there, while those of Atkins (1930) show that even less 

 phosphate is regenerated in the English Channel. Obviously the conditions at South 

 Georgia, where the phytoplankton, despite the abundance of nutrient salts, is very poor, 

 are entirely diflFerent. 



In support of this argument, that here the land drainage actually lowers the amount 

 of nutrient salts, the comparatively low phosphate values found in the upper layers of 

 the enclosed basin of Moranen Fjord (Table LV) may be cited. This fjord is fed by three 

 large glaciers and cut off from Cumberland Bay by a reef over which there are only 

 2-7 m. of water. Inside it shoals very steeply and becomes very deep. About two 

 hundred yards inside the reef soundings were obtained in 24 m., and farther up no 

 bottom could be reached with a 40-fathom (73 m.) hand line. Returning later with 

 another line, a sounding was obtained in 146 m. about three cables from the northern 

 edge of the Hamburg glacier face. Owing to the reef, the larger fragments of glacier ice 

 tend to drift round inside the fjord, in which the shores are mostly free from kelp, while 

 on the outside of the reef kelp grows very luxuriantly. The formation of this fjord would 



