ISSN:0020-9309    

DOI:10.1002/iroh.19780630202

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY

摘要:

AbstractThere is considerable variation in published phosphorus‐chlorophyll relationships, some of which can be accounted for by variation in sampling and analytical techniques. As well, there can be significant inherent variability in a single phosphorus‐chlorophyll relationship under even ideal sampling and analytical conditions. A survey of the literature shows that the cellular chlorophyll content of algae ranges over two orders of magnitude (0.1—9.7% of fresh weight). Average daily radiation intensity and nutrient availability (especially N) appear to be the major factors controlling chlorophyll content of algal cells. The relationship between total phosphorus and phytoplankton biomass for a group of Ontario lakes is better defined if summer average cell volume is used instead of average chlorophyll a concentr

ISSN:0020-9309    

DOI:10.1002/iroh.19780630203

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY

摘要:

AbstractPeriphytic biomass in a downriver riffle of the Grand River in Southern Ontario, Canada was measured with concrete‐block glass slide samplers from May to December 1971. Average rate of accumulation of periphyton on glass slides was 266.2 mg/m2/day ash‐free weight, 120.9 mg/m2/day carbon, 20.4 mg/m2/day nitrogen, or 1.11 mg/m2/day chlorophyllaand on concrete blocks was 590.0 mg/m2/day ash‐free weight, 202.9 mg/m2/day carbon, 22.8 mg/m2/day nitrogen, or 2.95 mg/m2/day chlorophylla.The standing biomass of periphyton on glass slides varied from a maximum of 21.6 g/m2between May 28 and July 15 to a minimum of 0.7 g/m2in December with an average of 8.6 g/m2. The biomass on concrete blocks ranged from a high of 132.5 g/m2in August to a low of 29.9 g/m2in October with a mean of 66.1 g/m2. The well established periphyton on concrete blocks towards the end of the study period was similar to that from native rocks with respect to biomass, carbon and nitrogen contents, and ratios of biomass to chlorophylla.This suggests that concrete blocks are a better substrate than glass slides for measuring riverbed periphyton. By comparing biomass of periphyton on slides and on concrete blocks, the average rate of loss of periphyton from concrete blocks was estimated to be 2.9 g/m2/day, representing 63% of the mean total accumulation rate of the periphyton. The magnitude of the estimated total loss and the high standing biomass of the periphyton on concrete blocks manifest the importance of the periphyton as a source of organic matter in the

ISSN:0020-9309    

DOI:10.1002/iroh.19780630204

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY

摘要:

AbstractThe historical background and utilization of southern Saskatchewan is described. The utilization of the saline lakes is discussed and the rationale for studying them is outlined.

ISSN:0020-9309    

DOI:10.1002/iroh.19780630205

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY

摘要:

AbstractThe geology and physiography, climate, soils and vegetation of the saline lakes region of southern Saskatchewan are briefly reviewed. The location and morphometry of 60 saline lakes was determined. Some of them are large (307 km2) but mean depths do not exceed 10 m and many are very shallow. Light penetration varied considerably from very turbid shallow lakes to Redberry Lake where the 1% light level was below 16.5 m. Light extinction coefficients for the entire water column of deeper lakes (7) varied from 0.256 to 2.558.Shallow lakes failed to stratify thermally but a dozen deeper lakes stratified for at least several months. Higher salinity tends to prolong stratification. Thermal stratification augmented chemical stratification in two meromictic lakes. Maximum temperature up to 30 °C in very saline shallow waters was recorded while temperatures as low as‐3 °C occurred under the ice. Freezing was delayed and thawing accelerated in more saline lakes. Annual heat budgets varied from 3350 to 13,900 g cal cm‐2in seven lakes.Oxygen concentration was reduced below thermoclines and was virtually absent below the ice in very shallow lakes and, at times, in a very productive

ISSN:0020-9309    

DOI:10.1002/iroh.19780630206

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY

摘要:

AbstractThe influence of anaerobic conditions on the distribution of bacteria has been studied. At the interface mud — water, bacteria using organic compounds of small molar weights come into sight, showing that the mud releases organic matter into the superficial water column which promotes mixotrophic alga

ISSN:0020-9309    

DOI:10.1002/iroh.19780630207

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY

摘要:

AbstractPiburger Bach is a short, spring‐fed lake affluent. The macrozoobenthos of this stream has been studied both qualitatively and quantitatively. More than 15,000 specimens of invertebrates, including all developmental stages of insects, were collected; a high proportion of these was identified to the genus or species level. The spatial and temporal distribution of various taxa as well as their quantitative contribution to the total macrobenthos are discussed. Confidence limits of the data are considere

ISSN:0020-9309    

DOI:10.1002/iroh.19780630208

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY

摘要:

AbstractAbnormally high chlorophyll values have been observed in the deep layer of the Saguenay Fjord, Québec, Canada. Experiments were conducted to assess the capability of this darkened phytoplankton to photosynthetize upon reillumination. It was found that photosynthetic capacity is well retained by deep phytoplankton of the Saguenay, as shown by relatively high production rates, a low tidal variability of these rates and very high P : B ratios

ISSN:0020-9309    

DOI:10.1002/iroh.19780630209

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY

摘要:

AbstractIn the freshwater turbellarian,Opistomum pallidum, facultative self‐fertilization occurs. The duration of development follows the van't Hoff/Arrhenius temperature rule. An acceleration of development is caused by a crowding effect at low temperatures. In the natural habitat, one generation requires 6‐7 months, lasting from November to May, or 2‐3 months from March t

ISSN:0020-9309    

DOI:10.1002/iroh.19780630210

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY

摘要:

AbstractEffects of rinsing and preservation on dry weight, organic weight, and chemical composition were determined on the chaetognathSagitta nagaeand the copepodsCalanus sinicus, Pleuromamma xiphiasandAcartia tonsa.Samples rinsed with distilled water were always lighter than comparable samples rinsed with seawater, showing apparent decrease in the organic matter and chemical contents (as total carbon and nitrogen) by weight; these losses increased with increasing volume of the rinse water. The volume of distilled water used for rinsing should be less than 0.3 ml per 1 mg dry weight of sample in order to avoid the significant loss of body substances. Isotonic ammonium formate rinse often resulted in the widest range of variation and on an average the organic weight and chemical contents were slightly lower than those of fresh samples rinsed with filtered seawater. Freeze‐drying samples resulted in dry and organic weights as well as chemical compositions that were somewhat greater than oven‐dried samples. The organic matter and chemical contents by weight decreased significantly within 2.5 days of being placed in Borax‐buffered formaldehyde‐sea water solution. Loss of organic weight from fresh samples exceeded 20% after one week of the preservation. Hexamine‐buffered formaldehyde solution showed a result which was different from the Borax‐buffer

ISSN:0020-9309    

DOI:10.1002/iroh.19780630211

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY