Glacier-fed Rivers Research Articles

Fine structure of olfactory epithelium inSchizothoraichthys progastus McClelland andSchizothorax richardsonii Gray (Cyprinidae: Teleostei) from Garhwal Himalaya (India)

The olfactory epithelium of two closely related species of snowtrout—Schizothoraichthys progastus McClelland andSchizothorax richardsonii Gray (Subfamily: Schizothoracinae. family-Cyprinidae, Teleostei), from a perennial glacier-fed river Mandakini of Garhwal hills was studied by employing transmission electron microscopic method The olfactory lamella comprises two epithelia—anterior and posterior, with a stroma sandwiched in between. Both are strartified. The anterior one is thicker than posterior. InSchizothoraichithys progastus, the sensory part of epithelium has two types of receptor cells—ciliated receptor cells and rod cells whilst inSchizothorax richardsonii, there arc three types of receptor cells—ciliated receptor cells, microvillous receptor cells and rod cells in addition to sustentacular cells, basal cells and mucous cells. While inhabiting similar hillstream habitat, the differential ecological niches, feeding habits etc., account for the presence of different receptor cell types in these species, It implies the possible diversification at cellular and physiological levels so as to minimize the competition by using varied olfactory cues.

EFFECTS OF LIME‐SLUDGE DISCHARGE ON AN ARCTIC RIVER1

ABSTRACT: The Fairbanks Water Treatment Plant in Fairbanks, Alaska, processes approximately 3 MGD of drinking water using lime softening. Approximately 0.3 MGD of lime‐sludge from the treatment process is combined with effluent from a nearby power plant and discharged to the Chena River. There is little information available on the impact of water‐treatment sludge discharges, and virtually no information on the impacts of such discharges in polar environments. Concern surrounding the discharge of water treatment sludges have centered on alum‐sludge due to the potential toxic effects of aluminum. Because of the relatively benign composition of lime‐sludge, very little research has been published. However, there is the possibility that discharge of solids will result in sedimentation, accumulation of solids, and subsequent impacts on benthic organisms. This paper reports on the results of a study to determine if lime‐sludge discharge from the water treatment plant is adversely impacting the river environment. The results provide basic information on the important variables of concern in lime‐discharges to rivers.Samples from the discharge of the water treatment plant and combined water treatment plant/power plant effluent were collected weekly over a one‐year period, and in‐stream benthic and water column samples were collected biweekly during the fall and spring. Sediment and water quality data indicate that while significant accumulation of sludge solids is found downstream of the water treatment plant outfall, they are flushed out of the system by spring flows, which are significantly increased by snow melt. This process is most likely repeated on a yearly cycle.Hence, the data suggest that the FMUS water treatment plant's discharge of lime‐sludge is probably not adversely impacting the river. More generally, this may indicate that the natural flow variations and sediment‐laden characteristics of Arctic, glacier‐fed rivers may assimilate large quantities of nonputrescible solids without significant changes in the natural river environment. Further research in this area is required to verify this conclusion.

Short term variations of a glacier-fed river

The main factors determining the short term variations of the river Thjorsa in Iceland are rainfall and the melting of snow and glaciers. Time dependent spectral analysis was applied to investigate seasonal variations in the second order properties of the variations of Thjorsa and their relationships with temperature and precipitation. In late summer a linear model of Thjorsa and the temperature and precipitation at the meteorological station at Haell provides a good fit of the observations. Because of non-linear effects connected with snow melting linear models are less appropriate during the winter although they can still explain a significant proportion of the variations of Thjorsa. The most important information for predictions a few days ahead are past values of the river itself. Some improvement can be achieved by also taking meteorological observations into account. DOI: 10.1111/j.2153-3490.1970.tb00500.x

Short term variations of a glacier-fed river

The main factors determining the short term variations of the river Thjorsa in Iceland are rainfall and the melting of snow and glaciers. Time dependent spectral analysis was applied to investigate seasonal variations in the second order properties of the variations of Thjorsa and their relationships with temperature and precipitation.In late summer a linear model of Thjorsa and the temperature and precipitation at the meteorological station at Haell provides a good fit of the observations. Because of non-linear effects connected with snow melting linear models are less appropriate during the winter although they can still explain a significant proportion of the variations of Thjorsa.The most important information for predictions a few days ahead are past values of the river itself. Some improvement can be achieved by also taking meteorological observations into account.

The natural history of the Hardangerfjord

Abstract As a part of a general survey of the natural history of the Hardangerfjord, in the county of Hordaland, Norway, a study of the benthonic algal vegetation was made; this was carried out mainly in summer. The area includes the outer coastal area, the outer fjord area (archipelago) and the fjord proper, where glacier-fed rivers discharge very turbid water during summer floods. The algal vegetation changes in composition from the outer to the inner reaches of the area, the “fjord effect” consisting mainly in an impoverishment of the littoral as well as the sublittoral flora. On entering the fjord proper, the lower limit of the vegetation rises from about 30 m to 10–15 m. This level was recorded throughout the fjord, even in the fjord branches where turbidity is very high in summer. The environmental factors which appear to be mainly responsible for the gradual reduction in the number of species are salinity range and water movement (turbulence, exposure). The latter is also suggested as responsible f...

The natural history of the Hardangerfjord

Abstract Measurements of submarine light were undertaken in the Hardangerfjord (West Norway) in the summers of 1955 and 1956. Discharge of very turbid water from glacier-fed rivers during their summer floods produces very low transparency in some of the fjord branches. From the inner to the outer part of the fjord a gradual increase in transparency takes place. A pronounced difference in the spectral composition of the submarine light of the very turbid inner waters and of the ordinary coastal waters at the mouth was recorded. For glacier-fed rivers with sedimentation basins Tyndall readings demonstrated a great reduction in turbidity during the passage through the lakes.