摘要:

MayfliesTimpanoga hecuba, caddisfliesDicosmoecus gilvies, mosquitoesCulex peusand midgesCricotopussp. were tested in the laboratory to determine the effects of air-supersaturated water on survival and adult emergence. The acute 96-hour LC50 value (lethal concentration which killed 50% after 96 hr) for mayflies was 128.9% saturation. Times to death and mean times to 50% death were determined. Adult midges and mosquitoes emerged at 141% and 143%, respectively. Good survival and emergence occurred in controls for all test groups. Adult mayflies did not successfully emerge or survive at concentrations of ≥135%. Adult caddisflies did not emerge at concentrations of ≥134%. Bubbles which were observed in body fluids caused buoyancy problems and raised the insects to the water surface. Data indicate that mosquitoes were highly tolerant and midges were moderately tolerant of air-supersaturated water. Mayflies and caddisflies were relatively sensitive. All insects were more tolerant of air-supersaturated water than fish species.

ISSN:0270-5060    

DOI:10.1080/02705060.1981.9664039

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Diptera from Grenada Reservoir (40 km2) were collected monthly from February, 1973 through August, 1975. Fourteen genera and 13 species were identified. Aquatic stages ofChaoborus punctipemis(Say),Coelotanypus tricolor(Loew), andChironomus attenuatus(Walker) constituted over 90% of all dipterans collected. Diptera were distributed throughout the reservoir and constituted the single most important component of the macrobenthos. Certain species were ubiquitous while others were restricted by depth or substrate. Changes in water temperature, dissolved oxygen, and water level controlled emergence, repopulation and larval migrations. Populations showed mid-winter highs and stunner lows with some species having as many as four generations per year.

ISSN:0270-5060    

DOI:10.1080/02705060.1981.9664040

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Estimates of benthic algal primary productivity in a stream measured by14C incorporation and dissolved oxygen change gave similar pattern of productivity over the year. However, estimates from the14C procedure were lower than from the D.O. change procedure. The discrepency is related in part to procedural differences but the data from experiments in which14C uptake and D.O. change were measured simultaneously also indicated the community photosynthetic quotients were higher than those commonly used in productivity work.

ISSN:0270-5060    

DOI:10.1080/02705060.1981.9664041

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The movement of six walleyes (Stizostedion vitreum vitreum) ranging in size from 470 to 655 mm were tracked in pool 3 of the upper Mississippi River during 1973 and 1974. The study area consisted of a combination of main channel and slough-lake backwater habitats. Continuous tracking of each walleye after release revealed two major movement patterns; a variable meandering movement where the direction changed rapidly and often, and a relatively straight line cruising behavior. The variable meandering movement was most commonly observed in the vicinity of sunrise and sunset and seemed to correspond to a feeding behavior. The cruising behavior seemed to randomly occur throughout the day and night and was generally followed by a rest period ranging in length from two to six hours. Active fish tended to be active during both the diurnal and nocturnal hours. Fish which were less active remained so for the entire diel cycle. Broad use of river habitats occurred although areas with a slight flow were preferred. Normal swimming speeds ranged from 0.5 to 1.5 body lengths/second (BL/s). Smaller fish exhibited short but rapid spurts of speed ranging from 2 to 3 BL/s. Field observations suggest that the latter swimming is part of a walleye elusive-behavior pattern.

ISSN:0270-5060    

DOI:10.1080/02705060.1981.9664042

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Four methods often used in preparing leaves for studies on the fate of leaves falling into mid-latitude streams were analyzed in a tropical rainforest stream. Both t h e techniques and plant species affected processing rates for four species of tropical wet forest riparian plants. More leaf area remained for fresh leaf disks than for dried leaf disks. Photometric rather than the usual dry leaf mass measurement techniques were used because, 1) leaves do not have to be dried before they are used, 2) artificially dried leaves do not simulate natural conditions, especially in humid tropical forests, 3) leaves can be measured photometrically and replaced in streams without damaging tissue, 4)photometric methods are commonly used in terrestrial studies on leaf damage and these methods should be equally adaptable to aquatic systems, and 5) the correlation between leaf area loss and dry mass loss for terrestrial studies has been shown to be high; therefore, dry mass data from studies on aquatic leaf decomposition studies are expected to be similar to photometrically-derived leaf area data.

ISSN:0270-5060    

DOI:10.1080/02705060.1981.9664043

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

An easily constructed device was designed to suspend an Ekman bottom grab by its jaws. The device makes cocking the grab and collecting samples easier, safer, and more efficient.

ISSN:0270-5060    

DOI:10.1080/02705060.1981.9664044

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Oxygen consumption ofIsoperla clio,I. namataandI. nananymphs that simultaneously occupied the same habitat in Alabama was determined at nine different temperatures from 2.5–22.5 C on a Gilson Differential Respirometer. Q10values indicated thatI. cliowas most sensitive to temperature change. Weight specific oxygen consumption-temperature relationship showed that the threeIsoperlaspecies had the same degree of tolerance to temperature, but the volume of oxygen consumed per unit body weight was inversely related to the species' mass. Generally the metabolic response to temperature change was dependent on body size and the stage of ontogenetic development.

ISSN:0270-5060    

DOI:10.1080/02705060.1981.9664045

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The elemental composition of eight aquatic macrophytes from Okefenokee Swamp, Georgia was examined during a comprehensive survey.Nymphaea odorata Ait., Nuphar advenaAit.,Pontederia cordataL.,Lachnanthes caroliniana(Lam) Dandy,Xyris smallianaNash.,Rhynchospora inundata(Oakes) Fern.,Sphagnum cuspidatumvar. serrulata (Schlief.) Schlief., andUtriculariasp. (Utricularia purpureaWalt.,U. junceaVahl. andU. inflataWalt.) were sampled from seven marshes and partitioned into roots, rhizomes, stems, petioles, leaves and flowers. Ash, phosphorus, potassium, calcium, magnesium, sodium, aluminum, iron, and manganese were analyzed with a plasma emission spectrograph. Upper plant parts contained higher concentrations of K, Ca, Mg, Na, and Mn than roots and rhizomes. Iron and aluminum concentrations were highest inUtriculariaand submersed roots. Elemental concentrations were similar to these in aquatic macrophytes found in other regions.

ISSN:0270-5060    

DOI:10.1080/02705060.1981.9664046

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

A new method of using artificial substrates for quantitative periphyton measurement was given preliminary testing over a 30 day period in Fleming Creek, Washtenaw County, Michigan. Results were encouraging, as this technique was found to be less time consuming than other methods. It also appears that this new procedure could be a valuable tool in addressing the problem of high variability between replicate periphyton samples. In this experiment variation of chlorophyllaconcentrations between glass slides was reduced to 4%.

ISSN:0270-5060    

DOI:10.1080/02705060.1981.9664047

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Zooplankton collected with a 153-μm mesh net in Quantico Creek and the adjacent Potomac River were dominated bv the rotiferBrachionus- plicatilis, the cladoceranBosmina longirostris, and the copepodites and adults of cyclopoid copepods.Eurytemora affiniscopepodites and adults,Brachionus calyciflorus, Diaphanosoma brachyurum, and at least five other cladoceran genera and two other rotifer genera were also relatively abundant. Bimonthly zooplankton samples contained fewest organisms (186/m3) in February and maximum numbers (286,000/m3) in June. Rotifers were the most numerous taxon in April, cladocerans dominated the collection in December and June, and copepods were a majority of the organisms collected in February; in August and October species composition was more evenly distributed among the major groups. During periods of psak abundance, zooplankton were concentrated in Quantico Creek and the sampling locations closest to the mouth of the creek as opposed to the more open Potomac River stations. The high densities of rotifers in Quantico Creek nearly coincided with maximum numbers of egg and larval white perch. Early larval white perch have been shown to feed on rotifers such asBrachionusspp. Obvious advantages accrue to fish species such as white perch, which inhabit areas of increased zooplankton densities, relative to species such as striped bass, which remain mostly in the mainstream Potomac River.

ISSN:0270-5060    

DOI:10.1080/02705060.1981.9664048

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor