OLR (1983) 30 (12) E. Biological Oceanography 929

10.0 #g-at N/L; this cycle resembled that of NH4 + although urea concentrations were usually lower. Urea uptake was inhibited by NH4 ÷ concentrations higher than 1 to 2 /~g-at N/L. The summed 'NH4 ÷ plus NO3- plus urea' uptake rate was exponentially related to temperature. Dept. of Mar. Biol. and Limnol., Univ. of Oslo, P.O. Box 1069, Blindern, Oslo 3, Norway.

83:6784 Lancelot, Christiane, 1983. Factors affecting phy-

toplankton extracellular release in the Southern Bight of the North Sea. Mar. Ecol.-Prog. Ser., 12(2):115-121.

Light intensity had no effect on percent extracellular release (PER). A high negative correlation between PER and mineral N concentration was found during the spring bloom when flagellates dominated the phytoplankton; physiological response of flagellate populations to shortage of nutrients differed. High PER was measured during bloom decline with lower values in oligotrophic (46%) than eutrophic (70 to 80%) waters. No significant correlation was found between PER and mineral N for diatoms which dominate the phytoplankton the rest of the year. Lab. d'Oceanogr., Univ. Libre de Bruxelles, 1050 Bruxelles, Belgium.

83:6785 Mullin, M.M. and W.T. Williams, 1983. Spatial-

temporal scales of zooplanktonic assemblages in three areas of the North Pacific: a further analysis. Deep-Sea Res., 30(5A):569-574.

Spatial faunal changes were more significant in the California Current and nearshore zones; diurnal- nocturnal changes were relatively more important in the central gyre. Faunal assemblages occurring in smaller patches in the central gyre did not imply ecologically important unpredictability. Inst. of Mar. Res., Univ. of California, La Jolla, Calif. 92093, USA.

83:6786 Nalewajko, C. and K. Lee, 1983. Light stimulation of

phosphate uptake in marine phytoplankton. Mar. Biol., 74(1):9-15.

Effects of light on phosphate uptake were inves- tigated; maximum stimulation, to about 2.7 times dark uptake, was observed in the Strait of Georgia where phytoplankton were limited by light but not P. Stimulation was similar, about 1.8 times the dark rate, in the northern Sargasso Sea, where phyto- plankton were probably limited by phosphate but not by light. Minimal stimulation was observed in a Maine estuary where the population appeared to be

neither P nor light limited. Scarborough Coll., Univ. of Toronto, West Hill, Ontario, Canada.

83:6787 Shumakova, G.V. et al., 1983. Pelagial ecosystems.

(Bacteria, plankton, chlorophyll a, trace ele- ments, and biogenous element uptake by phy- toplankton.) Ekol. mor., Akad. Nauk Ukr. SSR, 1983(12):3-34; 5 papers. (In Russian, English abstracts.)

83:6788 Turner, J.T., S.F. Bruno, R.J. Larson, R.D. Staker

and G.M. Sharma, 1983. Seasonality of plankton assemblages in a temperate estuary. Mar. Ecol. (P.S.Z.N. I), 4(1):81-99.

Large seasonal fluctuations were present in all measured parameters (T, S, nutrients, chl a, pro- ductivity), as well as in the composition and abundance of the plankton. Two of Greve and Parsons' (1977) proposed trophic pathways char- acterize the estuary: 'nanoplankton ~ small zoo- plankton ~ gelatinous zooplankton carnivores' for the warmer season and 'net plankton ~ larger zooplankton ~ young fish' for the colder season. NMFS, NOAA, SEFC, Beaufort, NC 28516, USA. (ahm)

83:6789 Weisse, T., 1983. Feeding of calanoid copepods in

relation to Phaeocystis pouchetii blooms in the German Wadden Sea area off Sylt. Mar. Biol., 74(1):87-94.

Positive correlations between algal concentration and abundance of Acartia spp. and Temora longi- cornis suggest that P. pouchetii is an important food organism for the copepods in spring and early summer. In laboratory experiments, maximum food intake reached 48% of body C per day in A. clausi and 87% in T. longicornis. Inst. fur Meeresk., Dusternbrooker Weg 22, 2300 Kiel 1, FRG.

El00. Nekton (communit ies; also fish, rep- tiles, mammals)

83:6790 Bowen, W.D. and D.E. Sergeant, 1983. Mark-

recapture estimates of harp seal pup (Phoca groenlandica) production in the northwest Atlan- tic. Can. J. Fish. aquat. Sci., 40(6):728-742. NW Atlantic Fish. Centre, Dept. of Fish. and Oceans, P.O. Box 5667, St. John's, Nfld. AIC 5XI, Canada.