NSIS Volume 37 - Part 2
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Item Open Access Table of contents (v. 37, p. 2)(Dalhousie Printing Centre, 1988-05) Nova Scotian Institute of ScienceItem Open Access Instructions to authors and acknowledgement(1988-05) Nova Scotian Institute of ScienceItem Open Access The scaleless dragonfish, Melanostomias valdiviae, Brauer, 1902, new to the fish fauna of Atlantic Canada(Dalhousie Printing Centre, 1988-05) Coad, B.W.Item Open Access Primary production of two small lakes in Atlantic Canada(Dalhousie Printing Centre, 1988-05) Howell, G.D.; Kerekes, Joseph J.At Layton’s lake, Nova Scotia, the total annual primary production was estimated to be 182 gC m-2 y-1 of which 87 gC m-2 y-1 was planktonic production. Macrophyte production accounted for the additional 95 gC m-2 y-1.The macrophytes appeared to be inhibitory to the phytoplankton during the summer growing season, as indicated by the low chlorophyll-a concentrations. Total phosphorus and maximum chlorophyll-a concentrations were the best trophic indicators, suggesting that Layton’s lake is eutrophic. Long Lake, New Brunswick, had an estimated annual primary production of 36.4gC m-2 y-1 due solely to phytoplanktonic production. Variations in daily areal production values could be explained largely by variations in surface insolation and flow rate. Neither total phosphorus concentration or chlorophyll-a concentration were good trophic indicators. It is suggested that peak chlorophyll-a concentration is the best trophic indicator for long lake, resulting in borderline oligotrophic-mesotrophic classification.Item Open Access The effect of lime on the zooplankton population of Sandy Lake, Halifax County, Nova Scotia(Dalhousie Printing Centre, 1988-05) Strong, K.W.Liming of Sandy Lake, Nova Scotia, during July and August of 1981 produced an abrupt and transient increase in the pH of the lake and concurrent changes in the zooplankton community. Immediately following liming, the cladoceran Bosmina longirostris could not be recovered from the lake but returned the following year after pH levels had fallen to pre-liming levels. The acidophilic rotifer Keratella taurocephala was also less numerous subsequent to liming. Other species, particularly rotifer species, were either more numerous or were collected for the first time in the two years immediately following the liming.Item Open Access Fermentation volume control in stirred vessels of working capacity ten liters(Dalhousie Printing Centre, 1988-05) Mason, F.G.; Taylor, A.The volume of fermentation liquid in stirred vessels of working capacity ten liters can be controlled during 14 days fermentation within the range 9.95-10.05 L by supporting the vessels on a spring the expansion of which is used to magnetically close a reed switch thus activating a pump to add sterile water (or medium) to the fermentor. As the weight of the fermentor increases by this addition, the spring is compressed and the reed switch opened. The success of the system depends on the use of suitable flexible couplings to the fermentor head-plate including a sliding spline coupling between the motor-drive and the impeller shaft. Drawings of this coupling and its associated electronics are given. The system has been used for more than 25,000 hours without break-down and can be easily adapted to computer control and hence chemostat operation.