bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geoarchaeological investigations of henson creek: A low‐order tributary in Central Texas
Authors: Nordt Lee C. 
Published: February 2007

AbstractA complex late Quaternary alluvial history was documented along Henson Creek, a low order tributary on the Fort Hood Military Reservation in central Texas. Three Quaternary alluvial landforms were recognized: terrace 2 (T2), terrace 1 (T1), and the modern floodplain (T0). The late Pleistocene T2 terrace may contain an array of sites spanning the entire known cultural record, while T1 may have sites spanning the last 5000 years only. Five fluvial units, three colluvial facies, two alluvial fan facies, and two buried paleosols were also recognized. Fluvial deposition was occurring approximately 15,000 yr B.P., 10,000‐8000 yr B.P., 7000–4800 yr B.P., 1650‐600 yr B.P., and during the last 400 years. Colluvial deposition was ongoing mainly in the early and middle Holocene, while alluvial fan aggradation was proceeding primarily in the middle Holocene. Because of erosional unconformities, there is minimal potential for recovering buried sites dating to intervals between depositional eposides for most of the drainage basin. Preservation potentials for buried sites are greatest in fine‐grained fluvial deposits dating to the late Pleistocene, early Holocene, and parts of the late Holocene, and in fine‐grained colluvial deposits dating to the early and middle Holocene. This investigation demonstrates that within the study area, and perhaps throughout much of central Texas, a greater continuum of sediments and preservation potentials exists in late Quaternary alluvial deposits of rivers than in low‐order tributaries.
AMS 14C age constraints on geoglyphs in the lower colorado river region, arizona and california
Authors: Werlhof Jay Von , Casey Harry , Dorn Ronald I. , Jones Glenn A. 
Published: February 2007

AbstractGiant ground figures are widespread in the lower Colorado River area of southwestern North America, yet their chronology has remained unconstrained by numerical ages. Thirteen AMS 14C measurements reported here indicate that geoglyphs were made from before ˜A. D. 1200 to before ˜900 B. C. We account for potential contamination from prior organics in weathering rinds. All other potential errors point to 14C dates being minimum‐limiting ages for the manufacturing of geoglyphs. Although these ages indicate considerable chronological complexity among geoglyphs, our data are consistent with the linguistic hypothesis that the Yuman people in the desert of southeastern California migrated from Baja California—rather than from the north. These results must, however, be placed under the cloud of uncertainty that hangs over the entire field of AMS dating of rock art: the untested assumption surrounding contemporeneity of organics in a surface context. © 1995 John Wiley & Sons, Inc.
Artifact size and spatial process: Macro‐ and microartifacts in a mississippian house
Authors: Sherwood Sarah C. , Simek Jan F. , Polhemus Richard R. 
Published: February 2007

AbstractDespite their evident utility in archaeological analysis, microartifacts (those artifacts smaller than 2 mm) have, as a class, been used only sparingly by archaeologists and then only as if they were larger artifacts. This article explores the variable information microartifacts contain, using a case study from the Loy Site, a Mississippian village in East Tennessee. We show that microartifacts provide different information from that obtained from macroartifacts. We also demonstrate that comparisons among different size classes provide new information on dynamic aspects of artifact deposition. Especially in spatial analysis, comparing distributions of different size artifacts enhances our interpretative capabilities over any single artifact size class.
Holocene landscape evolution and its impact on the neolithic and bronze age sites in the Shangqiu area, Northern China
Authors: Jing Zhichun , Rapp George (Rip) , Gao Tianlin 
Published: February 2007

AbstractThe Shangqiu area, situated on the alluvial plain of the lower Yellow River, is traditionally considered the center of the predynastic and early Shang culture. Archaeologic remains dating to predynastic and dynastic Shang periods, however, have remained elusive. The current pattern of Neolithic and Bronze Age sites is characterized by their upland settings; and it has been often assumed that the area had the same landscape from the Neolithic through recent historic time. The potential impact of geomorphic processes on these early sites has been hardly considered in developing archaeologic models of temporal and spatial distribution of these sites. This article first presents a reconstruction of the Holocene floodplain history in the archaeologically significant area. On the basis of stratigraphy and sedimentology, a Holocene landscape evolution model is constructed to explore the interrelationship between evolving landscape and archaeologic record of the Neolithic and Bronze Age. The prolonged landscape stability from very late Pleistocene or early Holocene to 2000 yr B. P. provided potential Neolithic and Bronze Age human occupation with a favorable physical environment. After 2000 yr B. P., the hydrologic regime changed and the floodplain experienced 2‐3 m of gradual vertical accretion during the following millennium. In response to the dramatic change of hydro‐logic regime after the early 12th century A. D., a new floodplain formed by dominantly overbank deposition, and the old floodplain surfaces are covered by as much as ten meters of the younger alluvium. As a result, a pronounced effect has been imposed on the preservation, visibility, and discovery of the Neolithic and Bronze Age sites, including those sites of predynastic and early Shang phases. Thus, much difficulty has been imparted to our understanding of the configuration of these early archaeologic sites. This study demonstrates the usefulness of landscape reconstruction in developing settlement models of Neolithic and Bronze age sites in the area.
Vertical Distribution of Bacteria and Algae in a Tropical Lake
Authors: Schmidt Gottfried W. 
Published: February 2007

AbstractIn another paper (SCHMIDT, 1969b) the relations between the numbers of bacteria and phytoplankton in the surface layers of some waters near Manaus (Amazonas) were reported. As a stratification of phytoplankton is not possible, due to the strong turbulence in the Rio Solimões (Amazon River), and since current was also present in the Rio Negro off the bays and littoral regions, the vertical distribution of bacteria and algae was of special interest in the Lago do Castanho, the third of the waterbodies investigated in the paper mentioned above. In the present study, two important fractions of bacteria, their total number, and the fraction of saprophyta (estimated by the number of bacterial colonies), were also differentiated.
The Development of Plankton Communities in Strip‐Mine Lakes of the Cologne Lignite District
Authors: Trahms Karl‐Jürgen 
Published: February 2007

AbstractIn former brown‐coal areas in the process of being returned to agriculture and forestation, there are holes left from the mining which are filled with groundwater. Three such strip‐mine lakes in the Cologne Lignite District were chosen for research purposes (i. e. the redevelopment by nature herself of plankton organisms). Despite a short research period (21/2 years) the analysis undertaken on lakes of different ages (40 years, 20 years and from the start) covers a span of 40 years. The main criteria of these waters are (1) extreme chemical conditions (sulphates = 400–500 mg/1, total alkalinity = 40–50° dH, permanent alkalinity: carbonate alkalinity max. 11:1), (2) poor in dissolved nutrient, phosphates non existent, (3) the lake form is not ideal (steep banks, no littoral) and (4) the unstable conditions. Comparison of the three lake ages shows an amelioration of the extreme chemical parameters, an increase in the number of the species of phyto‐ und zooplankton (tab. 4) and an increase of productivity running parallel with the ages. The waterborne inflow of organisms into these three lakes is more important than the transport by wind, birds, etc. as most of the lakes of the area are connected with one another (the same species and the same dominant species). The general conditions have been checked with other stripmine lakes, dams and reservoirs.
The Density and Production of Fish Populations in the Klíčava Reservoir (Czechoslovakia) and their Changes During the Period 1957‐1970
Authors: Holčík Juraj , Pivnička Karel 
Published: February 2007

AbstractThe results of 14 years of observations are reported concerning the species composition, ichthyomass (standing crop), total and available production, harvestable yield and balance of the fish population in the Klíčava reservoir (67 ha of area) in central Bohemia. Two stages of the reservoir development with regard to its fish are recognized and characterized. Some phenomena concerning the course of the ichthyomass and production, and the reasons for their fluctuations are discussed.
Prognose des Stoffhaushaltes von Staugewässern mit Hilfe kontinuierlicher und semikontinuierlicher biologischer Modelle. II. Prüfung der Prognosegenauigkeit. Prediction of the Balance of Matter in Storage Reservoirs by Means of Continuous or Semicontinuous Biological Models. II. Reliability of the Prediction Method
Authors: Benndorf Jürgen 
Published: February 2007

AbstractThe phosphate removal in small, completely mixed storage reservoirs (preimpoundment basins) mainly is a function of the production of biomass by the phytoplankton. The knowledge of the critical detention time of the water is the most important premise to the prediction. The critical detention time t̄ is computed from the equation: \documentclass{article}\pagestyle{empty}\begin{document}$ \overline t _c = \frac{1}{{\mu ^* - 0,1}} $\end{document} and the growth rate μ* at a given combination of the light intensity J, temperature T and phosphate concentration P is computed from: \documentclass{article}\pagestyle{empty}\begin{document}$ \mu ^* = \frac{{\mu T \cdot \mu J \cdot \mu P}}{{\mu \max ^2 }}\mu \max \cdot \frac{P}{{K_p + P}}\frac{J}{{K_j + J}}\frac{T}{{T_{opt} }}, $\end{document} (μmax = maximum possible growth rate of the dominant species; Kp, Kj and Topt are constants computed from batch cultures).The quotient \documentclass{article}\pagestyle{empty}\begin{document}$ \frac{{\bar t_{act.} }}{{\bar t_c }}(\bar t_{act.} = {\rm actual detention time in the water body)} $\end{document} enables prediction of the phosphate removal.A comparison of the predicted results from semicontinuous cultures and from the preimpoundment basin of the Weida reservoir revealed a satisfactory degree of conformity.
Detrimental Effects of Toxical Charge by Heavy Metals or Phenol on Submerged Water Plants (Fontinalis antipyretica L.)
Authors: Auerbach S. , Prüfer P. , Weise G. 
Published: February 2007

AbstractThe water moss Fontinalis antipyretica L. is well suited for measuring CO2 exchange by infrared gas analysis (IRGA), as only CO2 is used for assimilation. Both in a state of full activity and of reduced activity in the course of a toxical charge the ratio of net primary productivity to respiration related to intermittent illumination is used as a bioassay. Three types regarding the proportion of net assimilation (AN) to respiration (RD) are refered to the toxical charge (phenol, HgCl2, CuSO4, CdCl2). In the case of displacing the balance of AN/RD in the diurnal cycle to the side of respiration, photosynthetic oxygenation in the water ecosystem decreases. The combination of measuring CO2 exchange by IRGA with a cyto‐physiological investigation by determining the time of deplasmolysis of leaves is used for the prediction of vitality long before damage including lethal effects are to be recognizend morphologically.
Chemistry of Tasmanian Inland Waters
Authors: Buckney R. T. , Tyler P. A. 
Published: February 2007

AbstractA few of Tasmania's several thousand lakes and rivers have been sampled in a preliminary survey of water chemistry. They range in concentration from extremely dilute glacial lakes (TDS < 10 ppm) to hypersaline lagoons (TDS > 85%), the majority being dilute (TDS < 50 ppm). The 3 mechanisms controlling water chemistry proposed by GIBBS (1970) are seen to operate and the 3 terminal water types showing precipitation‐dominance, rock‐dominance and solubility‐limited composition are found, together with a range of intermediates. The majority of waters have seawater ionic composition or moderate geochemical modification of this.
Lakes Sorell and Crescent—A Tasmanian Paradox
Authors: Cheng D. M. H. , Tyler P. A. 
Published: February 2007

AbstractLakes Sorell and Crescent are closely adjacent shallow lakes on the Tasmanian Central Plateau. They have similar morphometry and similar climate, geology, soils and vegetation in their catchments. They are polymictic, oxygen‐saturated and colourless but turbid. They have soft water with major ions Na, Ca, Mg, Cl, HCO3present in almost equi‐ionic quantities, and a slightly alkaline reaction. Chemically they are alike, the major difference being a 20% higher salinity in Crescent from 1967–69. During 1969–71 heavy rains reduced this difference. Water frequently flows from Sorell to Crescent in any year.Despite these similarities their phytoplankton populations differ markedly in every respect—species composition, population structure, population stability and total biomass. Lake Crescent has a standing crop 10 X that of Sorell. The former is eutrophic, the latter mesotrophic. Well marked seasonal cycles do not occur but sporadic fluctuations of biomass are brought about by hydrologic or other events.The pronounced differences in every aspect of plankton populations in two so similar and connected lakes cannot yet be explained. They remain a limnological paradox.
Degenerative and constructive features of a phylogeneticcaly young cave form of Poecilia sphenops (Pisces, Poeciliidae)
Authors: Peters Nicolaus , Peters Gabriele , Parzefall Jakob , Wilkens Horst 
Published: February 2007

AbstractDARWIN's statement, that rudimentary parts of organisms are apt to be highly variable, is also true for the regressive structures of cavernicolous animals. On the other hand, adaptive traits develop under cave conditions, the variability of which is lowered rather than increased, compared to that of their precursors in the epigean population. These differences in the genetically controlled variability of constructive and degenerative features indicate action and nonaction of natural selection.
Site Variation in Littoral Periphyton Populations: Correlation and Regression with Environmental Factors
Authors: Brown S‐D. 
Published: February 2007

AbstractOver a six month period, littoral periphyton communities on vertically oriented glass slides were quantitatively sampled from four stations in Elk Lake, British Columbia. Correlation and multiple regression analyses were employed to assess the temporal interrelationships between 15 environmental variables, concurrently measured, and the periphyton populations, expressed as total cell counts and species diversity, for the complete data set of each station. At all stations there was a statistically significant increase in total cell populations with increasing length of slide exposure; positive correlations also occurred with pH, temperature, nitrite, nitrate and copper, while negative ones occurred with oxygen, orthophosphate and hardness (magnesium and total). At all but one station there was a significant decrease in species diversity with increasing slide exposure duration, a decrease attributed to the simultaneous increase in standing crop resulting in intensified competition for diminishing substrate area suitable for cell colonization. Multiple stepwise regression analyses demonstrated that greater than 80% of the variation in periphyton total cells at all four stations could be reliably predicted or described in terms of length of slide exposure, phosphate (ortho and total), and hardness (calcium and total). On the other hand, exposure duration and total cell populations were the most important variables associated with changes in species diversity at three of the four stations. In general, correlations and regressions between standing crop and environmental variables were more statistically reliable and consistent between stations than comparable analyses with species diversity. Use of multiple regression and correlation disclosed the importance of small, non statistically significant variation in ecologically relevant variables and permitted objective comparison of stations.
Faunistic‐Ecological Investigations on the Fresh Water Fauna of Subterranean Biotopes and Gypsum Caves in the Southern Harz and Kyffhäuser Mountains
Authors: Laminger Hilde 
Published: February 2007

AbstractA list of the subterranean fauna of the river basin and cave waters of the southern Harz Mountains and Kyffhäuser Mountains is given.Both the chemistry of the subterranean waters and the food chain relationships of the subterranean fauna are considered. The biota of the caves is compared to other subterranean fresh water biotopes, and the geographic distribution of the observed species is noted.
Die Verbreitung der Grünalge Chaetophora incrassata im Raum südlich der Ostsee
Authors: Pankow Helmut , Trampe Hartwig 
Published: February 2007

AbstractThe green alga Chaetophora incrassata, which LUTHER describes as alkaliphile, occurs in Lake Kraaz in the northern part of the G. R. D., although it is situated in a sandy region. The appearane can be explained by the special ecological conditions, especially the high input of nutrients and the pH value of 7.4.
Studies on the Regulatory Behaviour of Aquatic Ecosystems and its Significance for the Biological Phosphate Removal
Authors: Benndorf Jürgen , Stelzer Wolfgang 
Published: February 2007

AbstractAquatic ecosystems have the ability to compensate for oscillations of the inputs (substrate concentration, dilution rate, temperature). The mechanisms of this buffering capacity are studied in this paper (see fig. 7). The inputs exert an influence on the biomass and the activity of the organisms (activity = specific rate of RNA‐synthesis or specific P‐removal rate [μ/mg biomass day]). The activity is regulated either directly by the inputs and/or indirectly by the biomass. The activity decreases with an increase of the biomass (see fig. 5 and 6). The product of biomass and activity determines the transient response (= effective performance) of the system which is better buffered than biomass or activity alone.Considering the theory developed in this paper the effect of shock loadings on the phosphate removal in preimpoundment basins of drinking water reservoirs is discussed.
Limnological Investigations in Lakes of the Pokhara Valley, Nepal
Authors: Maeda Osamu , Ichimura Shun‐Ei 
Published: February 2007

AbstractFour subtropical mountain lakes in western Nepal were investigated for their plankton content and hydrographical conditions. Phytoplankton species composition, vertical distribution and seasonal variations were studied, and physical (temperature, visibility, electrical conductivity) and chemical (pH‐value, alkalinity) properties of the lakes measured. The lakes rank among the subtropical monomictic type with thermal stratification and have a very low electrical conductivity. The phytoplankton (made up of diatom‐desmid and dinoflagellate associations) comprised a mixture of species from tropical, Indo‐Malayan and temperate regions; species from temperate regions, however, predominated.
Penilia avirostris DANA in the Indian Ocean (Cladocera)
Authors: Croce Norberto Della 
Published: February 2007

AbstractThe records of the marine cladoceran Penilia avirostris DANA in the Indian Ocean are discussed as a further contribution to studies on the features of its world distribution. The review has pointed out different aspects of the life cycle of the species and the influence of biological and environmental factors upon the mechanisms of the cycle itself. Production of P. avirostris is considered on a trophic basis. Observations carried out elsewhere are also discussed.
Investigations Concerning the Influence of Hydrostatic Pressure upon the O2‐exchange of Marine Benthic Algae
Authors: Shameel Mustafa 
Published: February 2007

AbstractThe after effects of non‐ecological hydrostatic pressures were studied upon the rates of respiration and photosynthesis of certain benthic algae from the Baltic Sea, North Sea and the Mediterranean Sea. The influences of different pressure intensities and the different durations of pressure were analyzed. It was observed how different parts of the same thallus are effected in their gas exchange by the same pressure. The interrelationships between hydrostatic pressure and the different ecofactors e. g. temperature, salinity, pH and O2‐concentration of the external medium were also studied. Furthermore the seasonal variations, the behaviour of shallow and deep water algae, the comparison of different ecotypes and the differences in taxonomically closely related algae were observed in regard to their pressure resistance.
Species Diversity of Periphyton Communities in the Littoral of a Temperate Lake
Authors: Brown Sharon‐Dale 
Published: February 2007

AbstractSpecies diversity of littoral periphyton sampled from Elk Lake (B. C., Canada) was dependent on station location and period of substrate exposure. Site differences were not statistically related to physico‐chemical variables. However, diversity was negatively correlated with age of the communities and standing crop, and appeared to be associated with biological interaction or competition for available substrate surface. Further investigation revealed that the Shannon‐Weaver index, as commonly applied, was inappropriate for data summarization since it reflected only the changes in evenness of the most abundant species. Components of the diversity index, as illustrated by the periphyton, were discussed.
A Limnological Survey of Lake Mainit, Philippines
Authors: Lewis William M. 
Published: February 2007

AbstractMorphology, bathymetry and climate are described for Lake Mainit, one of the principal lakes of Southeast Asia. Thermal and water chemistry data show that the lake is not meromictic, despite its great depth, and that the water is dilute. Primary production is high but standing crop and diversity of phytoplankton and zooplankton range from moderate to low. The species composition of plankton and other biota is discussed.
Production and Utilization of Dissolved Organic Carbon During in situ Phytoplankton Photosynthesis Measurements
Authors: Allen Harold L. 
Published: February 2007

AbstractRates of phytoplankton photosynthesis, extracellular release of dissolved organic carbon, and production or utilization of dissolved organic carbon during in situ incubation were measured in a soft‐water Vermont lake during summer thermal stratification.Phytoplankton photosynthesis rates were frequently in the range of 300–600 mg C m−2 of lake surface day−1; extracellular release of previously fixed organic carbon was generally in the range of 20–75% of the carbon incorporated into cell biomass, as determined by gas‐phase radio‐analysis. Rates of increase or decrease in total dissolved organic carbon occurring in light and dark incubated phytoplankton samples, during brief (4 hour) in situ measurements, indicate that a significant fraction of the total dissolved organic carbon „pool”︁ is probably labile and rapidly being cycled.