摘要:

AbstractThe nature of the sediment of Drinking Lake in the Churchill River Basin in Canada was studied with special reference to its chemical and colloidal composition. Crystalline minerals present in the colloidal fractions of the sediment are quartz, cristobalite, feldspars, micas, amphiboles, vermiculite, chlorite and kaolinite. Sesquioxidic components and the extractable Ca and Mg are present not only in the colloidal fractions but also in the non‐colloidal fractions of the sediment. Over 99% of the nitrogen in the sediment is organic and about 60% of the sediment phosphorus is inorganic. The importance of the crystalline and non‐crystalline mineral components of the sediment studied in the exchange of nutrients between the sediment and its overlying water is discussed. In view of the important roles of these mineral components in affecting the transfer of nutrients, possible significant modifications of the quality of the lake water after impoundment, if a dam were constructed in the basin for a hydro‐electric development, deserve close atte

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620301

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

摘要:

AbstractA statistical analysis for the waters of the Darss‐Zingst inlets (Southern Baltic) using the rank correlation coefficient according to Spearman shows a significant correlation between the amount of phytoplankton and total dissolved nitrogen.In contrast, no correlation could be found between phytoplankton and total dissolved phosphoru

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620302

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

摘要:

AbstractAnnual planktonic primary production in five small oligotrophic lakes in Newfoundland, as measured at maximum depth (P‐area) ranged from 5.6 to 12.0 g C/m2/year. Production per unit surface area representative of the whole lake basin (P‐area ) was considerably lower in the shallower lakes (3.3 to 6.4 g C/m2/yr), while production expressed per unit volume representative of the whole lake basin (P‐vol ) was the higher in the shallower lakes (0.6 to 4.1 g C/m3/yr). Production efficiency varied from lake to lake and throughout the year, but it remained fairly stable in a shorter term. Production efficiency and insolation was used to estimate annual production. Lakes with higher summer concentration of total phosphorus had higher rates of carbon assimil

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620303

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

摘要:

AbstractEmbryos, larvae and fry of the cyprinidontidRivulus cylindraceus, subjected to sublethal concentrations of the branched alkyl benzene sulfonate TBS, were investigated with respect to mortality rates, deformities, hatching and activity (frequency of heart pulsation, pectoral fin beating and body movements of the embryos, swimming behaviour and activity of larvae and fry).If environmental conditions are optimal, sublethal concentrations seem to have no effect on an entire larval or young fish stock. On the other hand, if other stressing environmental factors of natural or human origin accompany them, such as lack of nutritional supply, an effect on a stock is possible at low sublethal concentrations.

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620304

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

摘要:

AbstractThe burrowing behavior of the holothurianLeptosynapta tenuis, its lebensspuren, and the types of peristaltic waves used in movement and burrow irrigation are described. Particle size selection is a function of accessability of grains.L. tenuiscannot distinguish between particle sizes but nevertheless ingests small particles in a lesser proportion than that found in the surrounding sediment. Feeding rates are 2900–5500 g ·yr−1· animal−1. These rates are strongly dependent on temperature. Computation of a sediment mixing budget shows that of all the sediment ingested, 51% is ingested from the top 1/2 cm of sediment, 75% from the top 3 cm. The significance of the funnel as a ‘tool’ to exploit the top 1/2 cm of sediment is discussed.L. tenuisdiffers from other deposit feeders in that (1) it removes small particles from the surface sediment during its reworking activities, (2) it reworks sediment downward as well as upward, (3) its reworking activities tend to increase the stability of the upper 3 cm of the sediment, and (4) because so much sediment is ingested from the top 1/2 cm, it reworks an entire sediment column less efficiently per gram of sediment ingested than many other depo

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620305

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

摘要:

AbstractThe adult habits and emergence ofDolania americana(Ephemeroptera: Behningiidae) were studied at the Blackwater River in Northwestern Florida. The adult life is crepuscular, beginning about 1½ hrs before sunrise with emergence of male subimagos. Males molt to imagos, female subimagos emerge, males and females mate, and females begin to oviposit in a fairly precise time sequence over the following hour. Only a few adults survive past sunrise. Females never molt to imagos and are polymorphic. Emergence is seasonal and begins between the end of April and the middle of May, depending on climatic conditions. Emergence is photoperiodically entrained. Water temperature is a phase setter and light intensity acts as a synchronizer

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620306

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620308

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY