摘要:

To quantify pollutional stress utilizing macroinvertebrate community composition, we use an average chi-square test with considerable success, and we present the method for further testing. Average chi-square is determined in the following fashion:

ISSN:0270-5060    

DOI:10.1080/02705060.1983.9664582

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Determination of oxygen consumption a t 20 ± 1 °C was made in nymphs of the dragonflySomatochlora cingulata.Three methods of measuring oxygen uptake rates were compared with respect to reproducibility and sensitivity. A flow-through regime, employing chemical titration of oxygen yielded the most reproducible results, though titration is not as sensitive as manometric based procedures. The Gilson respirometer and static chemical titration procedures were both more variable.

ISSN:0270-5060    

DOI:10.1080/02705060.1983.9664583

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Zooplankton in the tidal, freshwater Potomac River were usually unstratified in the water column. Vertical mixing caused primarily by tides apparently prevented stratification, hence the classic pattern of diel vertical migration was not found. Larger grazers could occasionally concentrate in deeper waters during daylight hours, so the mean distributions of zooplankton grazing pressure was slightly skewed towards the bottom. Zooplankton tended to exhibit patchy horizontal distributions, and densities along river transects could vary by an order of magnitude. Populations of zooplankton grazers during the 1981 summer could hypothetically remove an average of of 1.1% to 3.7% of the water column's phytoplankton each day. Estimated values ranged as high as 9.7% day-1.

ISSN:0270-5060    

DOI:10.1080/02705060.1983.9664584

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Diurnal and annual variations of physical and chemical parameters in a marsh within Okefenokee Swamp were examined during 1777 and 1978. Temperature, conductivity, oxygen, carbon dioxide, potassium, sodium, magnesium, and calcium were affected by physical and biotic factors that operated on different temporal scales. Temperature, carbon dioxide, and oxygen showed diurnal and seasonal patterns that are typical of shallow marshes. Conductivity was less than 80 μmphos cm-1and varied with O2and temperature. Dissolved cation concentrations, especially those of K+and Ng++, were low. Diurnal changes in K+and Na++concentrations were statistically significant and seemed to be related to biotic uptake and release.

ISSN:0270-5060    

DOI:10.1080/02705060.1983.9664585

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

This study measured the associations of alkalinity, current and invertebrate drift among 13 streams in subarctic Alaska. A significant positive correlation was found between alkalinity and drift concentration expressed as numbers per unit volume. Significant inverse relations were found between stream discharge and drift concentration expressed as either numbers or weight. This “dilution” was to be expected since stream wetted perimeter, the source of invertebrates to drift, increases as approximately the square root of the discharge. Multiple regression analysis also showed a positive relation between stream average velocity and drift concentrations. Invertebrate drift was seen, therefore, to be somewhat analogous to sediment transport in streams.

ISSN:0270-5060    

DOI:10.1080/02705060.1983.9664586

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The benthic invertebrates of Trout Creek in northwest Colorado were sampled from natural and multiplate artificial substrates at four stations over three seasons. Although artificial substrates collected lower numbers/m2and number of species, the greatest difference between substrates was exhibited in their respective insect communities. Artificial substrates collected fewer caddisflies and beetles and more dipterans, mayflies and stoneflies than were present in the natural substrates. Functional groups also exhibited this difference with scrapers predominant on natural substrates but not important on the artificial substrates. The multiplate substrates appeared to favor shredders at the upstream sites and filterers and gatherers at the rest of the stations. This probably is related to accumulation of debris on the samplers. These differences need to be considered when interpreting data from artificial substrates in mountain streams.

ISSN:0270-5060    

DOI:10.1080/02705060.1983.9664587

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

For the first time in 70 years, the occurrence of a “lake ball” in Lake Michigan is here reported in the literature. According to a published system of classification, the object we collected in 1978 was a “false” lake ball. Dissection revealed that it was colonized by 5 chironomid larvae and 162 oligochaetes. The species and numerical proportions of the oligochaetes indicated that it was formed in or near the mouth of a eutrophic tributary rather than in the open waters of Lake Michigan where it was found. Because of their mobility, false lake balls may be ecologically important, serving as natural vehicles for the dispersal of invertebrates.

ISSN:0270-5060    

DOI:10.1080/02705060.1983.9664588

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The habitat utilization and movements of largenouth bass (Micropterus salmoides), yellow perch (Perca flavescens), bluegill (Lepomis macrochirus) and pumpkinseed (Lepomis gibbosus) were studied via radio telemetry. Habitat utilization was calculated as the percentages of a tracking day each fish occurred in each habitat, weighted by the proportionate area of each habitat. The five habitats were heavy macrophyte (H), primarilyMyriophyllumsp.; light macrophyte (L), primarilyPotamogetonsp.; sand (S); open water (O), having an approximate minimum depth of 6 m and no macrophytes; ecotone (E), which was defined as 1.5 m on each side of a boundary between macrophyte beds and sand or open water. Movement speeds were determined by calculating the distance between two tracked locations at five minute intervals.

ISSN:0270-5060    

DOI:10.1080/02705060.1983.9664589

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

An 18-month study on Lake Chicot, Arkansas, has shown that spectral reflectance can be used to estimate the concentration of suspended solids in the surface water. Wavelengths between 700 and 900 nm give the best estimate of the concentration of suspended solids. This study shows that it should be possible to estimate the concentration of suspended solids in the surface water of Lake Chicot using remote sensing technology. Thus Landsat images, aerial photography, or sensors mounted directly over the water surface transmitting data could give a reservoir manager valuable data about suspended solids concentration that would be useful in making decisions on the management of water inflow to a lake or reservoir to control water quality.

ISSN:0270-5060    

DOI:10.1080/02705060.1983.9664590

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The electivity of young bluegills (Lepomis macrochirus) feeding on three species ofDiaptomuswas examined experimentally in aquaria. Young bluegills consumed more adult femaleD. floridanusthanD. mississippiensis, withD. dorsalisbeing consumed in the smallest numbers.

ISSN:0270-5060    

DOI:10.1080/02705060.1983.9664591

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor