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Articles 1861 - 1890 of 1981

Full-Text Articles in Environmental Monitoring

Historical Patterns Of Phytoplankton Productivity In Lake Mead, Richard T. Prentki, Larry J. Paulson Jan 1983

Historical Patterns Of Phytoplankton Productivity In Lake Mead, Richard T. Prentki, Larry J. Paulson

Publications (WR)

Lake Mead was impounded in 1935 by the construction of Hoover Dam. The Colorado River was unregulated prior to then and therefore was subjected to extreme variations in flows and suspended sediment loads. Hoover Dam stabilized flows and reduced suspended sediment loads downstream, but Lake Mead still received silt-laden inflows from the upper Colorado River Basin. The Colorado River contributed 97% of the suspended sediment inputs to Lake Mead, and up to 140 x 1O6 metric tons (t) entered the reservoir in years of high runoff. Most of the sediments were deposited in the river channel and formed an …


The Influence Of Lake Powell On The Suspended Sediment-Phosphorus Dynamics Of The Colorado River Inflow To Lake Mead, T. D. Evans, Larry J. Paulson Jan 1983

The Influence Of Lake Powell On The Suspended Sediment-Phosphorus Dynamics Of The Colorado River Inflow To Lake Mead, T. D. Evans, Larry J. Paulson

Publications (WR)

The Colorado River has been successively modified by the construction of several reservoirs, beginning in 1935 with the formation of Lake Mead by Hoover Dam. These reservoirs are located in a chain, and each one has an influence on the nutrient dynamics and productivity of the river and downstream reservoir. Lake Mead derives 98% of its annual inflow from the Colorado River. Historically, the Colorado River inflow was unregulated into Lake Mead. Regulation occurred in 1963, when Lake Powell was impounded by the construction of Glen Canyon Dam, approximately 450 km upstream. The formation of Lake Powell drastically altered the …


Effects Of Wastewater Discharges On Periphyton Growth In Lake Mead, Nevada-Arizona, Marsha Korb Morris Dec 1982

Effects Of Wastewater Discharges On Periphyton Growth In Lake Mead, Nevada-Arizona, Marsha Korb Morris

Publications (WR)

A study of the effects of secondary-treated wastewater on periphyton growth in Lake Mead, Nevada-Arizona was conducted from September 1979 to December 1980. Periphyton ash-free dry weight, chlorophyll-a, dominant species composition, and alkaline phosphatase activity were measured on fiberglass substrates. Substrates were incubated for two to four weeks in littoral and limnetic habitats. Physical and chemical variables and phytoplankton chlorophyll-a were measured concurrently.

Transparency increased with increasing distance from the discharge. Secchi depth ranged from 0.75 m at the discharge confluence (station 2) in August, to greater than 20 m at the most distant stations (stations 9 and 10) in …


State Of The Fisheries Report 1981, Department Of Fisheries And Wildlife, Western Australia Oct 1982

State Of The Fisheries Report 1981, Department Of Fisheries And Wildlife, Western Australia

Status Reports of the Fisheries and Aquatic Resources

Western Australia continues to be one of the leading fishing States in Australia. The total gross value of fish, crustaceans and molluscs for 1980/81 was $82.8 million (Table 1) to which may be added the value of the pearl culture industry resulting in a total value of approximately $100 million.


An Ecological Analysis Of Relic Diatoms In Sediments Of Las Vegas Bay, Lake Mead, David Ross Hetzel Jul 1982

An Ecological Analysis Of Relic Diatoms In Sediments Of Las Vegas Bay, Lake Mead, David Ross Hetzel

Publications (WR)

Relic diatoms in sediments of the inner Las Vegas Bay, near the Las Vegas Wash sewage inflow, were examined in order to assess historic trophic conditions in this area of Lake Mead. Diatom sedimentation rates and ratios of Araphidineae/Centrales (A/C) diatom groups were determined from sediment cores collected in the old wash channel 1.5 km from the sewage inflow (station 2), in a small cove 1.5 km further downstream (station 3) and in an adjacent embayment off Gypsum Wash (station 4). Diatom sedimentation rates generally increased from the bottom to the top of each core, but pronounced minima existed at …


Report No 49 - Geographically Restricted Plants Of Southern Western Australia, Barbara L. Rye Jan 1982

Report No 49 - Geographically Restricted Plants Of Southern Western Australia, Barbara L. Rye

Fisheries Research Reports

This publication lists 527 angiosperm species native to southern western Australia whose known geographical ranges are less than 100 kilometres long. A further 128 angiosperms are listed with geographical ranges between 100 and 160 kilometres. No fern or gymnosperm species in the region are known to be geographically restricted.

Apart from the presently unnamed species, a large majority of the rare plants of southern Western Australia are believed to be listed, including 86 of the species that have been gazetted as rare flora.

Less than 40% of the listed species are known to occur on conservation reserves and less than …


Report No 56 - 1981 Review Of Rainfall And Wetlands In The South-West Of Western Australia, J. A.K. Lane, D. R. Munro Jan 1982

Report No 56 - 1981 Review Of Rainfall And Wetlands In The South-West Of Western Australia, J. A.K. Lane, D. R. Munro

Fisheries Research Reports

An account is given of the biological principles involved in decisions concerning duck-shooting seasons in the south-west of Western Australia.

The conditions for waterfowl which prevailed during 1981 are described through the use of rainfall statistics and data obtained from the Department's wetland monitoring programme.

Rainfall was generally average over central and northern areas of the south-west during 1981. Rainfall in southern areas, however, was generally

below to much-below-average, although south coastal areas from Augusta to Albany received average falls.

Unusually heavy falls were recorded in North Coastal, North Central and Central Coastal Districts in May, and average falls were …


Report No 54 - A Guide To The Gazetted Rare Flora Of Western Australia: Supplement 1, Susan J. Patrick, Stephen D. Hopper Jan 1982

Report No 54 - A Guide To The Gazetted Rare Flora Of Western Australia: Supplement 1, Susan J. Patrick, Stephen D. Hopper

Fisheries Research Reports

On March 12, 1982 36 plants were added to and 4 plants were deleted from the schedule of flora proclaimed by the Minister for Fisheries and Wildlife to be rare, likely to become extinct or otherwise in need of special protection under Section 23F of the Wildlife Conservation Act 1950-1979. Descriptions and drawings of each of the 36 additions to the schedule are provided.

All 36 rare taxa are confined to the South West Botanical Province, most being concentrated in the Albany, Pingelly,

Moora and Wongan Hills wildlife districts. There is an urgent need for further studies on the conservation …


The Voluntary Water Quality Monitoring Program : 1982 Project Report, Barbara Welch, Judy Potvin, Mary Ellen Dennis Jan 1982

The Voluntary Water Quality Monitoring Program : 1982 Project Report, Barbara Welch, Judy Potvin, Mary Ellen Dennis

Maine Collection

The Voluntary Water Quality Monitoring Program : 1982 Project Report

by Barbara Welch, Judy Potvin & Mary Ellen Dennis

Division of Environmental Evaluation and Lake Studies, Maine Department of Environmental Protection, Augusta, Maine 1982.

Contents: Understanding Maine's Lakes and Ponds / Acknowledgement / Temperature / Dissolved Oxygen / Other Measures of Lake Water Quality / Nutrients / Algae and Chlorophyll a / Transparency / Morphometry / Sampling / Protection / Classification / Answers to Most Frequently Asked Questions / Glossary of Terms / Appendix A : Maximum, Minimum, and Mean Values / Appendix B : Phosphate Content of Common Cleansers …


The Ecology Of Maine's Intertidal Habitats : A Report Prepared For The Maine State Planning Office, Peter F. Larsen, Lee F. Doggett Oct 1981

The Ecology Of Maine's Intertidal Habitats : A Report Prepared For The Maine State Planning Office, Peter F. Larsen, Lee F. Doggett

Maine Collection

The Ecology of Maine's Intertidal Habitats : A Report Prepared for the Maine State Planning Office

by Bigelow Laboratory for Ocean Sciences (Authors: Peter F. Larsen and Lee F. Doggett) , 1981.

Contents: Acknowledgements / List of Tables / List of Figures / Chapter 1 - Introduction / Chapter 2 - Human Impact on Intertidal Fauna / Chapter 3 - A Primer of Intertidal Ecology / Chapter 4 - A Sampler of Intertidal Species / Chapter 5 - Methodology / Chapter 6 - Results of Faunal Studies / Appendix 1 - Habitats With Date Sampled / Appendix 2 - List …


State Of The Fisheries Report 1980, Department Of Fisheries And Wildlife, Western Australia Sep 1981

State Of The Fisheries Report 1980, Department Of Fisheries And Wildlife, Western Australia

Status Reports of the Fisheries and Aquatic Resources

Western Australia has maintained its position as the top fishing State. The catch in Western Australia of fish, crustaceans and molluscs in 1979/80 was worth $85.7 million to the fishermen, which is 27 per cent of the total value for Australia.


Diagenesis Of Organic Matter In Las Vegas Bay And Bonelli Bay, Lake Mead, James W. Murray, Carolyn J. Jones, Kathy Kuivila, Jeff Sawlan Jul 1981

Diagenesis Of Organic Matter In Las Vegas Bay And Bonelli Bay, Lake Mead, James W. Murray, Carolyn J. Jones, Kathy Kuivila, Jeff Sawlan

Publications (WR)

The interstitial water chemistry of the sediments of Las Vegas Bay and Bonelli Bay in Lake Mead has been studied as part of a comprehensive water quality study of those locations. Pore water and solid phase analyses were completed from four stations in Las Vegas Bay and two stations in Bonelli Bay. At both locations the pore water compositions and organic matter diagenesis in the sediments are dominated by sulfate reduction. This major role of sulfate reduction is unusual for lake sediments and reflects the fact that SO4 is the major anion in the lake water. In addition, gypsum …


Chemical And Biological Structure Of Lake Mead Sediments, Richard T. Prentki, Larry J. Paulson, John R. Baker Jun 1981

Chemical And Biological Structure Of Lake Mead Sediments, Richard T. Prentki, Larry J. Paulson, John R. Baker

Publications (WR)

Lake Mead has undergone a serious decline since Glen Canyon Dam was constructed 450 km upstream in 1963.

State fisheries management agencies are concerned that the decline was caused by water level fluctuations and more severe drawdowns during the bass spawning season, when the operation of Hoover Dam was altered during the post-Lake Powell period.

The construction of Glen Canyon Dam and formation of Lake Powell in 1963 drastically altered the natural discharge and temperature cycles and decreased suspended sediment and nutrient loading in the Colorado River inflow to Lake Mead. Recent studies indicate that these changes in nutrient loading …


Maine's Whitewater Rapids And Their Relevance To The Critical Areas Program, Janet Mcmahon Apr 1981

Maine's Whitewater Rapids And Their Relevance To The Critical Areas Program, Janet Mcmahon

Maine Collection

Maine's Whitewater Rapids and Their Relevance to the Critical Areas Program

by Janet McMahon

Planning Report No. 74, Critical Areas Program, 184 State St., Augusta, Maine,

April, 1981 (additions made in October, 1981). Reprinted July, 1983.

Contents: Introduction / Natural History of Whitewater Rapids / Methods / Criteria / Results / Conclusions / General Evaluation of Whitewater Rapids for Inclusion on the Register of Critical Areas / Bibliography / Action Plan


Report No 41 - A Survey Method For Identifying Roadside Flora Suitable For Conservation In Western Australia, John K. Scott Jan 1981

Report No 41 - A Survey Method For Identifying Roadside Flora Suitable For Conservation In Western Australia, John K. Scott

Fisheries Research Reports

A survey method for identifying flora suitable for conservation alongside roads in south-western Australia was derived from an examination of characteristics of road verges. Two roads, from Midland to Toodyay and from Armadale to Bunbury, were examined. Width of verge, weed cover, soil disturbance, vegetation structure, presence of public utilities, evidence of fire and the type of adjoining land were measured at one mile (1.6 km) intervals on both sides of the road. Also recorded were aesthetic qualities such as stands of beautiful trees and sites of special interest, e.g. the presence of rare plants.

Three variables, percentage weed cover, …


Report No 42 - A Guide To The Gazetted Rare Flora Of Western Australia, Barbara L. Rye, Stephen D. Hopper Jan 1981

Report No 42 - A Guide To The Gazetted Rare Flora Of Western Australia, Barbara L. Rye, Stephen D. Hopper

Fisheries Research Reports

Descriptions and illustrations are provided for the first 100 taxa which have been gazetted as rare, likely to become extinct or in need of special protection under the Wildlife Conservation Act 1950-1979. Most of these rare taxa are restricted to the South-West Botanical Province and more than one-third occur in the Albany Wildlife District.

An outline is given of the means adopted to determine which taxa are gazetted as rare, the legal provisions for their protection and the biological data being sought for their management.


Fisheries Report No 45 - The Short Term Effects Of Brush Harvesting On The Kwongan Vegetation At Eneabba, Western Australia, E. A. Griffin, A. J. M. Hopkins Jan 1981

Fisheries Report No 45 - The Short Term Effects Of Brush Harvesting On The Kwongan Vegetation At Eneabba, Western Australia, E. A. Griffin, A. J. M. Hopkins

Fisheries Research Reports

Areas of the kwongan vegetation south of Eneabba are currently being harvested to provide brush for rehabilitation after mining. Because of the botanical importance of the Eneabba kwongan, a study of the effects of the harvesting was initiated. Three areas with different harvest histories were sampled using quadrats paired across cut/uncut boundaries. Floristic and structural differences between quadrats and between areas were assessed. The store of seed in uncut vegetation was measured.

There was a loss of species as a result of harvesting, at least in the short-term. Many species regenerated by resprouting from buds in damaged stems or in …


Report No 47 - 1980 Review Of Rainfall And Wetlands In The South-West Of Western Australia, J. A.K. Lane, D. R. Munro Jan 1981

Report No 47 - 1980 Review Of Rainfall And Wetlands In The South-West Of Western Australia, J. A.K. Lane, D. R. Munro

Fisheries Research Reports

An account is given of the biological principles involved in decisions concerning duck-shooting seasons in the south-west of Western Australia.

The conditions for waterfowl which prevailed during 1980 are described through the use of rainfall statistics and data obtained from the Department's wetland monitoring programme.

1980 was the fifth consecutive year of below-average rainfall in all five Meteorological Districts of the south-west. 1976 to 1980 was thus' the south-west's driest five-year period since 1913 at least.

Low rainfall during 1980 resulted in a further decline in the condition of wetlands throughout most of the inland south-west, Few gauged wetlands increased …


The Distribution And Relative Abundance Of Aquatic Oligochaeta In The Upper Cache River System, Southern Illinois, In Relation To Water Quality, Mark Julian Wetzel Jan 1981

The Distribution And Relative Abundance Of Aquatic Oligochaeta In The Upper Cache River System, Southern Illinois, In Relation To Water Quality, Mark Julian Wetzel

Masters Theses

Species composition, distribution, abundance, and water quality relationships of aquatic oligochaetes occurring in the upper Cache River system, southern Illinois were investigated. Forty-two taxa of oligochaetes including 16 naidids, 22 tubificids and representatives of the families Aeolosomatidae, Branchiobdellidae, Enchytraeidae, and Lumbriculidae were collected. Four species of oligochaetes new to Illinois, Limnodrilus psammophilus Loden, L. rubripenis Loden, Psammoryctides (Spencerius) californianus Brinkhurst, and Haemonais waldvogeli Bretscher were collected during this study. Another species of Limnodrilus new to science is reported here, as yet undescribed. The thesis that aquatic oligochaetes can be used as true water quality indicator organisms is rejected. It is …


Bulletin 3929 - Irrigation In Western Australia, K S. Cole Dec 1980

Bulletin 3929 - Irrigation In Western Australia, K S. Cole

Bulletins - 3000 - 3999

Irrigation is essential in many parts of the world to produce essential food and profitable cash crops. Generally, those areas of land with less than 360 mm of rain spread over a distinct wet season of several months cannot grow crops for food or cash on rainfall alone. Then irrigation becomes necessary unless some peculiarity such as an oasis exists.


Methods For Biological, Chemical, And Physical Analyses In Reservoirs, Penelope E. Kellar, Sherell A. Paulson, Larry J. Paulson Dec 1980

Methods For Biological, Chemical, And Physical Analyses In Reservoirs, Penelope E. Kellar, Sherell A. Paulson, Larry J. Paulson

Publications (WR)

This manual contains detailed descriptions of biological, chemical and physical sampling and analytical procedures used at the Lake Mead Limnological Research Center. The manual was prepared in response to requests made by numerous individuals involved in the Las Vegas Valley Water Quality Program. This manual represents what we consider to be a reasonably complete compilation of methods useful in studying both general and specific limnological questions. While each section is sufficiently detailed to be of use to investigators with little experience in limnological methodology, the methods can be used on a wide variety of lakes and reservoirs, with relatively little …


Litter Production And Nutrient Content Of Litter In The Seasonally Flooded Dismal Swamp, Marta M. Gomez Oct 1980

Litter Production And Nutrient Content Of Litter In The Seasonally Flooded Dismal Swamp, Marta M. Gomez

Biological Sciences Theses & Dissertations

Litter production was studied in four plant communities in the Great Dismal Swamp, Virginia, that differ primarily in species composition and flooding regime. Greatest leaf deposition occurred in the more flooded communities, maple-gum (Acer-Nyssa) with 536 g m-2 yr-1 and cypress (Taxodium distichum (L.) Richard) with 528 g m-2 yr-1, followed by the cedar (Chamaecyparis thyoides (L.) BSP) and mixed hardwood (Quercus-Acer-Nyssa-Liquidambar) communities with 506 g m-2 yr-1 and 455 g m-2 yr-1, respectively. Litter nutrient concentrations were generally higher in the cypress and maple-gum stands, indicating greater nutrient availability …


State Of The Fisheries Report 1979, Department Of Fisheries And Wildlife, Western Australia Jul 1980

State Of The Fisheries Report 1979, Department Of Fisheries And Wildlife, Western Australia

Status Reports of the Fisheries and Aquatic Resources

Western Australia has maintained its position as the top fishing State. The catch in Western Australia of fish, crustaceans and molluscs in 1978-79 was worth $91 million to the fishermen, which is 33 per cent of the total value for Australia.


Influence Of Las Vegas Wash Density Current On Nutrient Availability And Phytoplankton Growth In Lake Mead, John R. Baker, Larry J. Paulson Jun 1980

Influence Of Las Vegas Wash Density Current On Nutrient Availability And Phytoplankton Growth In Lake Mead, John R. Baker, Larry J. Paulson

Publications (WR)

Density currents are commonly formed in reservoirs because of temperature or salinity induced density differences between inflowing and receiving waters. Anderson and Pritchard (1951) were among the first to demonstrate this in their investigations of density currents in Lake Mead. They found that the Colorado River formed an underflow in Lake Mead during the winter, an overflow in the spring and an interflow in the summer and fall. Wunderlich and Elder (1973) have since described the hydromechanics of these types of flow patterns, and density currents have been reported for several other large reservoirs (Carmack et al. 1979, Johnson and …


Nutrient Interactions Among Reservoirs On The Colorado River, Larry J. Paulson, John R. Baker Jun 1980

Nutrient Interactions Among Reservoirs On The Colorado River, Larry J. Paulson, John R. Baker

Publications (WR)

Interactions among physical, chemical and biological processes in reservoirs can significantly alter the characteristics of the discharge (Neel 1963, Wright 1967, Hannan 1979) that, in turn, can influence the ecology of the river downstream .(Ward and Stanford 1979). Investigations of the Colorado River, system reveal that reservoir-induced changes in the river can also affect downstream reservoirs. The formation of Lake Powell, in 1963 was accompanied by reductions in suspended sediment and nutrient loading and changes in the seasonal temperature and discharge cycles of the Colorado River. In this paper, we evaluate how these changes have influenced the nutrient and trophic …


Macrobenthic Communities Of An Industrialized Seaport Ecosystem: The Southern Branch Of The Elizabeth River, Virginia, Steven D. Hawthorne Apr 1980

Macrobenthic Communities Of An Industrialized Seaport Ecosystem: The Southern Branch Of The Elizabeth River, Virginia, Steven D. Hawthorne

Biological Sciences Theses & Dissertations

Macrobenthic invertebrates of an industrialized seaport ecosystem were studied seasonally from October, 1977 through July, 1978. Five stations were selected along the Southern Branch of the Elizabeth River, Virginia. The stations ranged from an area of heavy industrialization to a non-urbanized environment. At each station, bottom water was measured for salinity, temperature, dissolved oxygen, and pH. Within each sampling area, macrobenthic infauna! invertebrates were collected from in and out of channel sites along with sediment samples for various types of physicochemical analysis.

Community structure was spatially homogeneous at station sites and throughout the stations along the River. Slightly acidic pH …


Evaluation Of Impacts Associated With Reregulation Of Water Levels In Lake Mohave, Larry J. Paulson, John R. Baker, U.S. Water And Power Resources Service Mar 1980

Evaluation Of Impacts Associated With Reregulation Of Water Levels In Lake Mohave, Larry J. Paulson, John R. Baker, U.S. Water And Power Resources Service

Publications (WR)

The U.S. Water and Power Resources Service is considering reregulating Lake Mohave water levels to increase the net power benefit from Hoover Dam. Reregulation will not increase the generation capacity of the Hoover powerplant but it will enable the plant operation to be increased when the energy has greater monetary value. Energy generated at different times of the year has different market value, the highest being in January-March and July- September. By generating more power during these periods more net monetary benefit can be derived from Hoover Dam. The total volume of water released from Hoover Dam over an annual …


Report No 40 - Commercially Exploited Vacsular Plants Native In Western Australia: Census, Atlas And Preliminary Assessment Of Conservation Status, Barbara L. Rye, S. D. Hopper, L. E. Watson Jan 1980

Report No 40 - Commercially Exploited Vacsular Plants Native In Western Australia: Census, Atlas And Preliminary Assessment Of Conservation Status, Barbara L. Rye, S. D. Hopper, L. E. Watson

Fisheries Research Reports

A census and atlas is provided of 1 119 native Western Australian plant species which were commercially exploited during 1977-79 in the cut plant, nursery or seed trades. The exploited species are concentrated in the vicinities of Perth and Albany, the two matin centres for the wildflower industry. Preliminary assessments of the conservation status of the exploited species are provided. Approximately r200 species are regarded as being rare, geographically or poorly collected, and further studies are recommended for these species to determine whether they are in danger of overexploitation.


Fisheries Report No 39 - The Wildlife Of The Proposed Toolonga Nature Reserve, Shark Bay Shire, Western Australia, A. A. Burbidge, P. J. Fuller, K. Cashin Jan 1980

Fisheries Report No 39 - The Wildlife Of The Proposed Toolonga Nature Reserve, Shark Bay Shire, Western Australia, A. A. Burbidge, P. J. Fuller, K. Cashin

Fisheries Research Reports

Following a Cabinet endorsed recommendation by the Environmental Protection Authority in 1975, an area of vacant Crown Zand (the Toolonga Area) was examined during April and September, 1978.

The geology, soils and vegetation of the area are described and annotated lists of mammals, birds, amphibians and reptiles are presented. A small part of the area lies in the South West Botanical Province (Irwin District) but most is in the Eremaean Botanical Province (Carnarvon District). The vertebrate fauna is a mixture of south-western, Shark Bay and arid zone species, but the last predominate.

The Toolonga Area provides an opportunity to protect …


A Limnological Study Of 43 Selected Maine Lakes, Derrill J. Cowing, Matthew Scott Jan 1980

A Limnological Study Of 43 Selected Maine Lakes, Derrill J. Cowing, Matthew Scott

Maine Collection

A Limnological Study of 43 Selected Maine Lakes

by Derrill J. Cowing and Matthew Scott

U.S. Geological Survey : Water-Resources Investigations 80-69

Prepared in cooperation with the Maine Department of Environmental Protection

U.S. Geological Survey, 26 Ganneston Drive, August, Maine 04330