946 resultados para Limnology

em Aquatic Commons


Relevância:

20.00% 20.00%

Publicador:

Resumo:

This short review includes major books, articles and episodes concerned with studies on inland waters that have affected the development of limnology in Argentina.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The study of limnology is important to understand ecosystem dynamics and the ecological basis for fish production in the Lake Victoria which is important for fisheries resources use, planning and management. Physical, chemical and biological parameters are important and known to influence fish population production. Energy fixed by primary producers, e.g. algae, is transfered to higher trophic levels, e.g fish. Factors which influence the dynamics of phytoplankton and zooplankton population, e.g nutrient availability and uptake, growth rate, species composition and biomass, ultimately affect fish production. The commercial fisheries of Lake Victoria consists mainly of piscivorous Lates niloticus (L>), algivorous Oreochromis niloticus (L.) and zooplanktivorous Rastrineobola argentea (Pellegrin)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The monthly variations in the physico-chemical parameters and zooplankton abundance were followed from December, 2003 to March 2004 in Makwaye (Ahmadu Bello University Farm) Lake, Samaru, Zaria. In this lake, all physico-chemical parameters investigated showed wide variations within the months except hardness, which exhibited highly significant variation both between stations and within months. Chemical variables including Na, Mg, Zn, Pb, Fe, K and Cu showed significant variations within the months. Three groups namely Cladocera (32.62%), Rotifera (29.33%) and Copepoda (38.05%) were observed. These indicated low species richness

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This short review includes major books, articles and episodes concerned with studies on inland waters that have affected the development of limnology in Argentina. It is divided into three periods; (1) an early period of protolimnologists; (2) a period previous to the present times, subdivided into a first stage from 1900 to 1938 and a second stage from 1938 to 1962; and (3) a period of integrated research.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The aim of this short article is to trace the history of limnology in Sicily, from the end of the last century up to the present, and pay a little homage to a scientist to whom limnology is deeply indebted: G.E. Hutchinson. Due to its insular and climatic conditions, Sicily is characterised by a drainage network formed by numerous short, torrent-like rivers, and by a few small, natural lakes. The geological characteristics of the island strongly condition the quality of these small waterbodies which generally have surface areas of less than 0.2 km super(2). The earliest observations on Sicilian lentic waters go back more than a century; in particular, at the end of the 19th century, some of the issues regarding the natural lakes had already been brought into focus. Subsequent studies on natural waterbodies concentrated on the geomorphology of landslide lakes or lakes created by the dissolution of the gypsum tableland. However, many of the waterbodies no longer exist because of land reclamation which took place up to the first half of the 1950s. During the last 35 years, there has been a notable increase in limnological publications. In addition, these studies show a more careful and integrated approach to the limnological aspects of waterbodies, compared with the early studies.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The high density of meres and mosses in the Delamere area comes from numerous moraine-hollows formed after the melting of stranded ice-blocks following last glaciation. The main vegetation is of conifers along with some deciduous species and the area was designated as a National Forest Park in 1987. It has been managed since the beginning of the 19th century and is a popular tourist area with walking, orienteering, cycling and educational activities. In recent years this forest park has been attracting over half a million people per year. This paper studies the limnology of different aquatic habitats in the Delamere Forest area in order to give some insight into the waters of a coniferous, temperate forest area, which has so far been largely unexplored. The authors assume therefore, thought that despite apparent large variability in origin, age, surface area, morphometry, catchment size and hydraulic regime, the waters of Delamere Forest might share some revealing chemical and biological features. Seven water-bodies in the Delamere Forest Park area, namely, Black Lake, Blakemere Moss, Delamere Lake, Delamere Quarry, Hatchmere, Windyhowe Farm Spring and Fir Brook were sampled, their water chemistry and dissolved organic carbon and the occurrence of phytoplankton and zooplankton species examined. In a final chapter the authors analyse their findings for patterns.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A limno-biological investigation was conducted in Chanda beel over a period of 8 months from June ‘95 to January ‘96. The floodplain showed temporal spatial and vertical variation in physico-chemical as well as biological conditions. During study period, physico-chemical parameters were within the suitable range for fish culture. Plankton population was higher in true beel areas. Both phytoplankton and zooplankton showed direct relationship among themselves. Presence of several indication plankton genera showed that the floodplain was eutrophic in nature.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper records the results of investigations of plankton, benthic fauna and fish fauna carried out between 1957 and 1963. The standing crop of net plankton in the lake was found to be 249.6 Kg/ha. This plankton is not being fully utilized by the fish fauna in the lake. Stocking the lake with a plankton feeder like Chanos chanos (Forskal) is recommended. The figure of 24.37 Kg/ha obtained for the standing crop of bottom fauna in the lake was comparatively low. This indicates that the bottom fauna is being fully utilized by the fish. The introduction and establishment of Tilapia mossambica (Peters) had not wiped out a single indigenous species of fish from the lake that produces about 2,000 lbs. of fish per acre per year. This can be increased by the introduction of a plankton feeder (Chanos chanos), and by further exploitation of existing stock.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Some morphometric, physical and chemical conditions of 21 lakes in Ceylon are described. The values for the organic matter in the plankton and for the dry weight of bottom fauna in the lakes have been calculated. These values have been utilised to evaluate the potential fish production figures for the lakes. Fishing trials were made in each lake. Suggestions regarding mesh sizes and time of fishing are put forward.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The present study deals with the chemical, algal and faunal characteristics of the stream system at Horton Plains, the highest plains in Ceylon (altitude 2'225 m). The cultivation of seed potatoes and subsequent use of fertilizers have caused extensive silting and severe eutrophication of the stream systems. Since there are no indigenous fish, the trout Salmo gairdnerii has been introduced and it is the only fish found in these streams. The commonest fauna in the streams are crabs (Paratelphusa sp.), shrimps (Caridimr sp.), Simulium sp. and Chironomus sp. Their increase in number is probably correlated with increase in organic and detritus matter. The most important food items of the trout are the crabs living abundantly in the stream, insect larvae and terrestrial insects were also commonly found in the guts. Records of stocking and taking of trout in the Horton plains streams have shown that now less trout are taken relatively to the numbers stocked. This decrease may be possibly due to the eutrophication of the stream and also due to the possible use of pollutants in connection with the cultivation of seed potatoes.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The present paper deals with the limnology of Nyumba Ya Mungu, a man-made lake in Tanzania (Kilimanjaro Region), during the 7th and 8th years after the elosure of the Ruvu dam. The area investigated included the River, which is one of the two rivers entering the lake.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Qualitative analyses of available photographs and maps of Merritt Island, Florida provide a large-scale, historical perspective of ecological changes of the marshes in the vicinity. Sites that deserve closer scrutiny can be identified. Secondarily, such an analysis provides a geographical orientation essential for communication not only between newcomers and those familiar with the area, but also among those familiar with the area but who refer to sites by differing methods. Photographs and maps from various sources were examined. Below are listed what we consider to be the most useful subset of these for ecological and geographical assessment of salt marsh impoundments on Merritt Island, Florida. (Document has 25 pages.)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This is a report to the California Department of Fish and Game. Between 2003 and 2008, the Foundation of CSUMB produced fish habitat maps and GIS layers for CDFG based on CDFG field data. This report describes the data entry, mapping, and website construction procedures associated with the project. Included are the maps that have been constructed. This report marks the completion of the Central Coast region South District Basin Planning and Habitat Mapping Project. (Document contains 40 pages)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In March 2007 CSU-Monterey Bay began hydrologic monitoring of Santa Lucia Preserve for the Santa Lucia Conservancy. This project is a continuation of monitoring begun by Balance Hydrologics as part of the permit requirements for land development. The purpose of this annual report is to present data summaries for the 2007 water year (October 1, 2006 to September 31, 2007). Rainfall in water year 2007 was very low, representing the 15 year drought rainfall. Streamflow was relatively low as well as indicated by baseflow conditions approaching the drought conditions of water-year 1991 (Croyle and Smith, 2007). Document contains 30 pages)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

“Advanced Watershed Science and Policy (ESSP 660)” is a graduate class taught in the Master of Science in Coastal and Watershed Science & Policy program at California State University Monterey Bay (CSUMB). In 2007, the class was taught in four 4-week modules, each focusing on a local watershed issue. This report is one outcome of one of those 4-week modules taught in the fall 2007 session. (Document contains 32 pages)