Showing papers on "Ecosystem published in 1972"

On the quantitative characteristics of the pelagic ecosystem of Dalnee lake (Kamchatka)

Abstract: The parameters of biomass and productivity of the main components of the pelagic ecosystem have been estimated in lake Dalnee (Kamchatka) during the first phase of the period of vegetation in July 1969. The water column in the lake during this period was stratified. The layer-character of vertical distribution of bacteria, phytoplankton, protozoa, rotifers and young stages of crustaceans was elucidated. The adult copepods migrate during the day. The nutrition of the mass species of zooplankton was studied using the C14-method. The data on the spectrum of feeding, on rations and on optimal food concentrations were ascertained. All these data, together with the observations in the lake, were used for the construction of a scheme of energy flow. The scheme shows that the ecosystem of the lake receives the third part of its energy from the land as allochtonous organic matter via microbial biosynthesis. The main part of energy accessible to the animals of the second trophical level is used by protozoa, and of a third part by the predatory rotiferAsplanchna.

Mineral Cycling: Some Basic Concepts and Their Application in a Tropical Rain Forest

Abstract: While the importance of mineral nutrition for plants and animals has been recognized for centuries, only recently has there been a systematic approach to mineral element cycling in entire ecosystems (47) By a systematic approach to ecosystem cycles we mean studies that yield estimates of the total amount of mineral elements and rate of element cycling within a complete landscape unit during a period of time, or under certain atmospheric or other physical conditions. Recent systematic studies (2, 43, 45, 50) have resulted in the formulation of several basic mineral-cycling concepts. In this paper we discuss several of these concepts in relation to a mineral-cycling study of a Puerto Rican tropical rain forest. Worldwide cycles of mineral elements have recently been discussed by Deevey (6). He focused primarily upon carbon, hydrogen, oxygen, and nitrogen and their reactions in the biosphere, lithosphere, hydrosphere, and atmosphere. It is our purpose to discuss principles of mineral cycles at the terrestrial ecosystem level. Because carbon, oxygen, and nitrogen are in a gaseous form for a large proportion of their cycling time, it is difficult to relate their cycles to the processes of a single ecosystem. Likewise, hydrogen, which moves in water vapor in the air is also difficult to relate to a single ecosystem. In contrast, cycles of elements such as calcium, potassium, and phosphorus that do not ordinarily volatilize can be more easily viewed in the context of one ecosystem. For this reason we have limited our discussion to this type of mineral element. The tropical rain forest mineral-cycling study on which this discussion is based was conducted between 1965 and 1969 and was part of the Atomic Energy Commission sponsored Ecology Project near El Verde, Puerto Rico. Background of the project and the results of a forest irradiation experiment have been compiled in a single volume (41), and methods used in the mineral-cycling study will be published elsewhere (20).

Fate of fertilizer nitrogen applied to a Northern Great Palins rangeland ecosystem.

Abstract: storing carbohydrate reserves. Clipping of the tops of Thurber stipa after 5 weeks of moisture stress was undoubtedly more detrimental to this species due to a higher proportion of the leaves still being physiologically active. Results of the second experiment were essentially the same as the first. The only notable difference was the slightly larger size of plants at the beginning of the 5-week moisture stress period.

Evaluating Forest Sites for potential Growth Response of Trees to Fertilizer

Abstract: Introduclion Greatly intensified forestry practices will be necessary to meet the wood fiber needs of the future. The demand for tirnber products is projected to increase about g0 per_ cent in less than 30 years (U.S. Forest Service, i965). A rapid rise in the demand for forest products and a substantial, steady decline in the nuilrber of acres of forest laad available for commercial timber productiot have created sfiong pressures for greatly intensifying forest maoagement pracices (U.S. Forest Service, i9i9l. _ A potentially powerful silvicultural tool, forest fertilization, is currently the subject of much interesr in connection with meering needs for sr:bstantially increasing growth rate of rrees. Evidence is accrrmulating that fertilizing forest stands has ofteo led to substantially improved tree growtl-r. Fertilizing do", ,rot guara[ree lmprovement in tree growth, however. Added outrients may bc fixed in the so in an unavailable form, volatilized, or lost by leaching. In addition, forcst productivrty is often more limited by unfavorable moisture and temperarure conditions than by nutltional de_ ficiencies. Costs of applying fettilizet to forest stands in the Douglas_fir region currently avetage about $23 per acre. These costs must be regarded o,-i.u"r,-.rrrs rn growing stock, and the increased growth musr be sufficient io pay back the mvestmenr plus rntetest. Ecoiogical considerations also are important in makiog decisions on the use of forest fertilizer. Public awareless afld concerfl over quality of the cnvironmeot indicate thar fotest managers will be under constraint,o urrui.t "ny unnecessary alteration of natural balances. For these reasons, we believe that mrtrients should be addetl only to those ecosystems in which we can be assured of an increase in tree producrivrty. N7e do not now posscss the information we oeed to determine where fettilizer will provide an economic response of tree growth (Strand and Miller, 1969). In this paper, v/e suggest that any satisfactory rnodel for understanding the environmental interactions that control productiviq. must include consideratiorx of (1) adequacy of the nutrient supply in soil; (2) adequacy of tree nutition; and (3) constraints on productivity other than nutrienm (such as moisture supply, temperature, and genetic factors). Results of our analyses agree with fin

Coastline ecosystems on oahu, hawaii

Abstract: Coatline ecosystems on Oahu, Hawaii were described in terms of vegetation composition and structure, and environmental components such as climate, physiography, exposure, substratum, and ground water. Vegetation patterns were related to these environmental components. Releves were established in 22 study areas around Oahu to study the broader patterns of vegetation and environment, and 2 m wide belt-transects were laid out in 16 areas to study structural and floristic zonation from the ocean edge to the limit of the strand flora inland. Physiographic position, substrate type, wind exposure and climate (through climate-diagrams) were determined for each site. Soil parameters determined along the transects were salt concentration, pH, organic carbon, moisture equivalent, soil moisture at 15 atmospheres pressure, and available moisture. Three levels of pattern in vegetation distribution were inferred. First, there were similarities and differences between study areas in terms of vegetation composition and structure, and environmental components. Thirteen ecosystem-classes were recognized on the bases of dominant species and landform: Hibiscus ecosystem on beach flat, Scaevola on dunes, Scaevola on talus and alluvium, Scaevola on raised coral rock, Scaevola on rocky basalt coast, Chloris-Sida on talus, Prosopis on dunes, Prosopis on talus and alluvium, Prosopis on tuffaceous headland, Chloris-Prosopis on dune and clay flat complex, Batis on mud flats, Rhizophora on tidal flats, and Scirpus-Eichornia in fresh-water pond. A second level of pattern was that of zonation into physiognomic zones, and a third that of “floristic zonation” or change in species composition with distance from sea. Only seven ecosystems, representing five ecosystem-classes (Scaevola on dunes, Scaevola on coral rock, Prosopis on dunes, Prosopis on talus and alluvium, and Prosopis on tuffaccous headland), showed distinct physiognomic zones. But all emerged ecosystems showed floristic zonation. The distribution of the ecosystems coastwise is most broadly related to rainfall and drought patterns, to exposure to wind and surf, and to salinity of soil and water. Hibiscus ecosystems occur in wet, protected beach flats of terrigenous sand, found in windward coasts; Scaevola ecosystems in areas exposed to intense wind and salt spray; Prosopis ecosystems and their variant, Chloris-Prosopis ecosystem, in droughtly areas of the leeward coast; Chloris-Sida ecosystem on rocky soils in the same droughty climate; Batis ecosystems on mud flats of high soil- and ground-water salinity; Rhizophora ecosystems in protected shorelines subject to tides; and Scirpus-Eichornia ecosystem in still fresh water. Salt concentration decreased markedly with distance inland in fine-textured soils, but showed only slight increases or decreases in coarse-textured dune soils. Organic matter showed increases, with three transects registering increases of 15% organic C at peak portions. pH was very variable; alkaline values arising largely from a high proportion of calcium carbonate parent material or high salt content and more acid values arising from greater organic matter incorporation. The range of many of the strand species has been increasingly limited by direct disturbance and indirectly by the seaward encroachment of introduced Prosopis. But they are still persisting (in larger or smaller numbers) in Scaevola ecosystems.

P32 movement through a freshwater laboratory ecosystem

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Degradation of Riparian Leaves and the Recycling of Nutrients in a Stream Ecosystem

Abstract: Leaves collected at 4 stations in the upper 5 km of Doe Run, Meade County, Kentucky, indicated an annual accumulation within the stream of 354 g/m2/year (17,700 kg). Leaves of sycamore (23.6%), red oak (21.7%), sugar maple (9.7%), beech (9.6%), white oak (7.1%), and hickory (6.0%) trees were most abundant, and leaves from 14 other kinds made up the remaining 22.3%. About a third of the annual leaf fall occurred during the last half of October and about two-thirds in the last 3 months of the year. Calorific equivalents for different kinds of leaves ranged from 3,789 cal/g dry weight for hickory to 4,417 cal/g for red oak. It is estimated that allochthonous leaf material made an annual contribution of about 70 million kcal of energy to the upper 5 km of Doe Run. Protein, carbohydrate, and lipid contents of leaves varied independently of seasons with average values of about 52, 79, and 32 mg/g dry weight, respectively. In leaves submersed in the stream experimentally, carbohydrates leached rapidly, lipids leached slowly, and there was an apparent increase in protein content. Indigenous amphipods preferred hickory, red elm, sugar maple, beech, red oak, and sycamore leaves as food in that order. VI-G Ecologic impact of water development Ecology RT Aquatic Habitats Detritus RT Decomposing organic matter Degradation (decomposition) ACKNOWLEDGMENTS We are grateful to the many members of the Faculty of the University of Louisville, especially Drs. William S. Davis, Burt L. Monroe, Jr., Stuart E. Neff, and Gradus L. Shoemaker for their valuable counsel and guidance throughout the study, and to the following graduate students for their assistance in the field and in the laboratory: Edmund J. Bacon, Jr., Claude D. Baker, Raymond T. Justice, Dale T. Kinney, Elizabeth Rush Liston, Bruce R. Wilson, and particularly Dr. John H. Yopp while he was a graduate student in the Department of Biology. Special gratitude is offered Dr. Charles R. Liston for the many hours spent in the field and laboratory collecting samples, making analyses, and compiling data. It was largely through his efforts that the study was completed. During his tenure as a graduate student, Dr. Liston received assistance as a National Science Foundation Trainee, and was supported in large part through Annual Allotment funds from the Office of Water Resources Research. His enthusiasm for the project is documented in these pages. The efforts of Harry H. Woodward deserve special mention. He assisted greatly in the collection and identification of plants in the Doe Run area, particularly those along the stream's edge. Specimens of all kinds of · plants collected are in the P.A. Davies Herbarium at the University of Louisville. We take this opportunity to thank Kay Craig, Sharon Pierce, Patti Vick, and especially Shirley Viers for typing the many revisions of the manuscript. This research is part of a long-range study on Doe Run which commenced in 1959 as a continuing study that would provide insight into the functioning of the stream as an ecosystem. None of that work could have been accomplished without the consent and cooperation of Messrs. Curtis L. Brown and Albert Holsten who allow continuing access to their properties along the stream. We are extremely grateful for their cooperation.

Manganese in lacustrine ecosystems: a review

Abstract: This paper serves as a literature review of manganese in fresh water. The major aspects of manganese occurrence discussed are: (1) sources, (2) geochemistry, (3) manganese-iron relationships, (4) effects on the fauna and flora and (5) detection.

Investigations on Nutrient Factors Limiting Phytoplankton Productivity in Two Central Virginia Ponds

Abstract: . Laboratory and field studies were initiated to evaluate at regular intervals by 14C and chlorophyll enrichment bioassay some of the nutrients, particularly ammonia, that might limit phytoplankton photosynthesis in two central Virginia ponds. Preliminary comparisons of the phytoplankton, their production, and the chemical characteristics of the water were determined. Ammonia, phosphate, nitrate, iron, carbon dioxide, silica and chloride differed most markedly among the various nutrients analyzed. Investigations were continued to compare the validity of using field and laboratory ecosystem work to predict changes in trophic levels resulting from nutrient enrichment, i.e., eutrophication. Laboratory experiments using aquatic microecosystems and field experiments employing in situ plastic cylinders and battery jars support the view that ammonia is a key factor regulating “trophic” features in these two ponds.

House-dust ecosystem

Abstract: House-dust and house-dust mites (Pyroglyphidae) are well known among allergologists, but less so among ecologists. House dust is the layer of dust covering floors and shelves, and the collection of particles which have penetrated into beds and stuffed furniture; the particles being mostly in the range of 10-3 to 1 mm. Air-borne dust also contains smaller particles but they do not easily settle. Quantitatively the dust consists of skin particles, cotton fibres, paper fibres, wool fibres, synthetic fibres, outdoor dust and a number of particles of other origins (Bordes and Zeylemaker, 1967). This dust, after it has settled, provides food and shelter for a community dominated by arthropods and fungi. The amount of dust present and its composition proved to be comparatively stable. It depended, among other things, on the cleaning habits of the human inhabitants of a certain house.