scholarly journals Impact of Lake Morphology and Shallowing on the Rate of Overgrowth in Hard-Water Eutrophic Lakes

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1827 ◽  
Author(s):  
Agnieszka Lawniczak-Malińska ◽  
Mariusz Ptak ◽  
Sofia Celewicz ◽  
Adam Choiński
Keyword(s):  
Hard Water ◽  
Strongly Correlated ◽  
Eutrophic Lakes ◽  
Vegetation Growth ◽  
Lake Volume ◽  
Physico Chemical ◽  
Lake Morphology ◽  
West Part ◽  
The 1960S ◽  
Phytoplankton Blooming

Lake disappearance is one of the results of water eutrophication which leads to lake shallowing and overgrowth, and small and shallow lakes are the most threatened with degradation. We studied the effect of lake shallowing on its overgrowth, taking into account the morphometric parameters of water bodies. The study was performed in 20 lakes located in the central west part of Poland. The degree of lake shallowing was evaluated on the basis of bathymetric maps made in the 1960s and studies carried out presently. Additionally, an analysis of littoral coverage and macrophyte growth forms was investigated. Moreover, the composition, intensity of phytoplankton blooming, and physico-chemical parameters of the lake water were analyzed. Redundancy analysis shows that the lake volume, average depth, shallowing rate, and change in volume were the parameters that most strongly correlated with the share of macrophytes in the lakes. According to the regression analysis, the share of emergent macrophytes was significantly correlated with lake shallowing. No relation was found between phytoplankton blooming and lake shallowing. Conversely, the lakes with the highest rate of shallowing were characterized by the greatest share of vegetation, which suggested that vegetation growth had a significant impact on lake shallowing.

Factors Controlling Oxygen Depletion in Ice-Covered Lakes

1980 ◽  
Vol 37 (2) ◽  
pp. 185-194 ◽  
Author(s):  
Jack A. Mathias ◽  
Jan Barica
Keyword(s):  
Volume Ratio ◽  
Lake Management ◽  
Eddy Diffusion ◽  
Oxygen Depletion ◽  
Eutrophic Lakes ◽  
Experimental Lakes Area ◽  
Lake Volume ◽  
Basin Morphometry ◽  
Depletion Rate ◽  
Prairie Lakes

Winter oxygen depletion rates from four sets of Canadian lakes (prairie, southeastern Ontario, Arctic, and Experimental Lakes Area) differing in morphometry and trophic state, were analyzed. An inverse relationship was found between oxygen depletion rate and mean depth. The effect of lake trophic status on oxygen depletion rate was demonstrable after the influence of basin morphometry was removed by regression of oxygen depletion rate against the sediment area: lake volume ratio. The sediments of eutrophic lakes consumed oxygen about 3 times faster (0.23 g∙m−2∙d−1) than those of oligotrophic lakes (0.08 g∙m−2∙d−1), but water column respiration was about the same (0.01 g∙m−3∙d−1) for both groups of lakes. Data from prairie lakes showed that the winter oxygen consumption was limited by oxygen supply below an average whole-lake oxygen concentration of 3.8 mg∙L−1. The rate of eddy diffusion near the sediments in ice-covered prairie lakes was 3.72 ± 1.41 × 10−3 cm2∙s−1. Implications for lake management during the winter are discussed.Key words: oxygen, depletion, respiration, lakes, ice-covered, winter, sediments, model, consumption

scholarly journals How slow breeding can be selected in seabirds: testing Lack's hypothesis

2006 ◽  
Vol 274 (1607) ◽  
pp. 275-279 ◽  
Author(s):  
F. Stephen Dobson ◽  
Pierre Jouventin
Keyword(s):  
Body Size ◽  
Strongly Correlated ◽  
Individual Selection ◽  
Ecological Constraints ◽  
Foraging Range ◽  
Reproductive Rates ◽  
The 1960S ◽  
David Lack

The historical debate of the 1960s between group and individual selection hinged on how the slow breeding of seabirds could be explained. While this debate was settled by the ascendance of individual selection, championed by David Lack, explanations for slow breeding in seabirds remain to be tested. We examined the slowest breeding of these birds, the albatrosses and petrels (order Procellariiformes), using analyses that statistically controlled for variations in body size and phylogeny. Incubation and fledging periods appeared strongly correlated, but this turned out to be largely explained by phylogeny. Nonetheless, developmental and reproductive rates were associated with the distance to the foraging range, as predicted under the hypothesis of ecological constraints on breeding pairs, and these results were independent of body size and phylogeny. Slower breeding in these seabirds appeared associated with the rigors of farther pelagic feeding, as Lack originally hypothesized.

scholarly journals CONCENTRAÇÃO DE FÓSFORO PRESENTE NOS RECURSOS HÍDRICOS: AVALIAÇÃO DO ÍNDICE DE ESTADO TRÓFICO DO BALNEÁRIO DE QUATÁ-SP

2018 ◽  
Vol 10 (Especial) ◽  
pp. 24-28
Author(s):  
Jaine D’Aurelio Carreira ◽  
Daniel Ângelo Macena ◽  
Jaqueline Nascimento da Silva
Keyword(s):  
Population Health ◽  
Trophic State ◽  
Fish Mortality ◽  
Water Color ◽  
Vegetation Growth ◽  
Standard Methods ◽  
Physico Chemical ◽  
Anthropogenic Action ◽  
Water And Wastewater

Water can undergo natural physico-chemical changes, but it is often caused by anthropogenic action due to improper disposal of effluent. These changes lead to eutrophication, which results in a high index of nutrients such as phosphorus and nitrogen, leading to vegetation growth. Other consequences may be fish mortality, dark water color of water, strong odor and transfer of pathogens, which endangers population health. The present work had as objective to perform analyzes of total phosphorus in the Municipal Spa of Quatá-SP. The method used for the analyzes was Phosphorus with Reactive Orthophosphate, adapted from the Standard Methods for the Examination of Water and Wastewater and the results were compared with the trophic state classes and the parameters of the legislation. At the end of the analyzes, the values obtained from EIT were considered high, compromising the quality of the water in some points.

scholarly journals Response of Prokaryotes to TOC Contamination in Dianchi Lake Sediments

2020 ◽  
Author(s):  
Cheng-Peng Li ◽  
Ya-Ping Li ◽  
Qing-Qing Huo ◽  
Wei Xiao ◽  
Yong-Xia Wang ◽  
...  
Keyword(s):  
Lake Sediment ◽  
Meta Analysis ◽  
Eutrophic Lake ◽  
Nucleotide Metabolism ◽  
Microbial Consortia ◽  
Dianchi Lake ◽  
Strongly Correlated ◽  
Eutrophic Lakes ◽  
And Function ◽  
Functional Profiles

Abstract Background: Explaining microbial consortia in sediments from the perspective of taxon, co-occurrence and function is the key to recover and maintain aquatic ecosystems. Trophic status was widely considered to be an important determinant of the lake sediment microbial community. However, little is known about the effect of a special eutrophic factor gradient on the prokaryotic community structure in situ. Within this context, we explored prokaryotic communities using an intensive field sampling from sediments in the Dianchi Lake, one of the most eutrophic lakes in China. Results: Microbial assemblages was strongly correlated with total organic carbon (TOC). Moreover, relatively high and low TOC shaped taxonomic and functional differences in microbial assemblages. The results identified the most abundant bacteria across all samples as Proteobacteria , Nitrospirae , Chloroflexi , Firmicutes , Ignavibacteriae , Actinobacteria , Bacteroidetes , Acidobacteria , Spiprochaetae and Latescibacteria . The dominant groups of archaea were Euryarchaeota , Woesearchaeota DHVEG-6 , Bathyarchaeota and WSA2 . Low TOC (LT) microbial assemblages displayed a major proportion of functional profiles related to some metabolisms such as carbohydrate metabolism, amino acid metabolism, energy metabolism, nucleotide metabolism and metabolism of cofactors and vitamins, membrane transport. These results illustrated that TOC concentration had obvious influence on the relative abundances of KEGG orthologs . Finally, the meta-analysis results highlight that most of network parameters of the LT community were significantly greater than those of other communities, which suggesting that the LT community was larger and more complex. Conclusion: TOC level might be a key determinant to shape taxonomic and functional construction of communities in Dianchi Lake sediment. LT community tended to establish a larger and more complex co-occurrence, which suggested that they may interact with each other strongly and exchange essential metabolites. Overall, this study could enhance our knowledge of microbial assemblages in eutrophic lake sediment and provide clues for the restoration and maintenance of sediment ecosystems.

scholarly journals Characterization of scale deposits formed in sanitary hot water pipelines in the northern tourist zone of Agadir city

2018 ◽  
Vol 7 (2) ◽  
pp. 86-92
Author(s):  
M'barek Belattar ◽  
Abdallah Hadfi ◽  
Said Ben Aazza ◽  
Said Mohareb ◽  
Naima Hafid ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Analytical Techniques ◽  
Hard Water ◽  
Hot Water ◽  
Infrared Spectrometry ◽  
X Ray ◽  
The North ◽  
Quality Of Water ◽  
Physico Chemical ◽  
Water Pipelines

The formation of scale on surfaces in contact with water is due to many reasons as the hardness of water and its temperature. Therefore, this phenomenon of scale in water pipelines is a common and inevitable problem in the regions that exploit or use groundwater with high rigidity. The circuits fed by hot water are easily reached by hard water scaling. The deposition of encrusting curst at the level of walls in touch with water is due to many technical, economic and environmental problems. It causes a reduction in water flow and a decrease in the efficiency of heating systems.In this study, we are particularly interested in studying the phenomenon of hard water scaling caused by sanitary hot water in a tourist unit situated in the north of the seaside in the city of Agadir. First, we have evaluated the physico-chemical quality of water in use in this tourist unit. Secondly, we conducted a qualitative and quantitative analysis of the scale found in the circuits that transport sanitary hot water. Several analytical techniques were used to reach this goal namely: X-ray fluorescence (XRF) which shows that 85.50% of scale is represented by Calcium Carbonate. Whereas infrared spectrometry (IR) demonstrates the existence of the Carbonate anion CO32-. In addition, due to thermogravimetric analysis (TGA) and differential thermal analysis (DTA) we found that the endothermic event shows the decomposition of Calcium Carbonate of CaO and CO2 in the temperature range of 660 C° to 820 C°. For scanning electron microscopy (SEM), it indicates that the scale takes the form of needle-like aragonite crystals. At last, the X-ray diffraction (XRD) shows that the scale is composed essentially of Calcium Carbonate of the type aragonite.The results of the different techniques of characterisation are in concordance in the scaling of the circuits of sanitary hot water in the tourist unit under study.

A Quiet Revolution in State Lobbying: Government Growth and Interest Populations

2020 ◽  
pp. 106591292097549
Author(s):  
James M. Strickland
Keyword(s):  
Interest Groups ◽  
Political Mobilization ◽  
The Political ◽  
State Governments ◽  
Strongly Correlated ◽  
Quiet Revolution ◽  
Government Growth ◽  
Secondary Sources ◽  
Original Dataset ◽  
The 1960S

What explains contemporary numbers of interest groups in America? To answer this question and help address conflicting narratives in research, I examine the rise of interest groups in the states. Assembling an original dataset based on archival and secondary sources, I find that relatively few groups lobbied legislators prior to the 1960s or 1970s. During those decades, numbers of interest groups began to grow rapidly. I find that increases in lawmaking activities present inconsistent effects on the political mobilization of groups but increases in spending are strongly correlated with mobilization. In additional tests, I find that the effects of spending on group numbers vary by state and are not discernible in most states. In general, a historic transformation of state governments helps to account for the growth of state lobbying. Interest groups have remained active in state capitols ever since.

scholarly journals Assessment of natural groundwater physico-chemical properties in major industrial and residential locations of Lagos metropolis

2019 ◽  
Vol 9 (8) ◽  
Author(s):  
Lekan Taofeek Popoola ◽  
Adeyinka Sikiru Yusuff ◽  
Tajudeen Adejare Aderibigbe
Keyword(s):  
Heavy Metals ◽  
Chemical Properties ◽  
Strongly Correlated ◽  
American Public Health Association ◽  
Chemical Parameters ◽  
Residential Locations ◽  
Standard Procedures ◽  
Physico Chemical ◽  
Groundwater Samples ◽  
Health Association

Abstract This study investigated groundwater quality collected from two industrial and residential locations in each of Lagos metropolis. Prescribed standard procedures of American Public Health Association were used to measure physico-chemical parameters of each of the groundwater samples which include pH, EC, DO, TDS, BOD, COD, anions (Cl−, NO3−, SO42−, PO43−) and heavy metals (Cu, Zn, Pb, Mn, Fe, Co, Cd and Cr). From laboratory analysis, measured physico-chemical parameters were within the permissible ranges specified by the WHO and NSDWQ except pH, TDS, EC, Pb, Mn and Fe for groundwater samples from industrial locations and pH, Pb, Mn and Fe for residential locations. Higher concentrations of TDS and EC reported for groundwater samples from industrial locations were attributed to heavy discharge of effluents from industrial treatment plants as well as dissolution of ionic heavy metals from industrial activities of heavy machines. Statistical Pearson’s correlation revealed physico-chemical parameters of water quality to be moderately and strongly correlated with one another at either p  < 0.05 or < 0.01.

Changes in nematode communities after manuring in millet fields in Senegal

Nematology ◽  
2003 ◽  
Vol 5 (3) ◽  
pp. 351-358 ◽  
Author(s):  
Cécile Villenave ◽  
Robert Oliver ◽  
Paula Fernandes ◽  
Klemens Ekschmitt ◽  
Tom Bongers
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Plant Production ◽  
Feeding Guilds ◽  
Strongly Correlated ◽  
Nitrogen Flux ◽  
Soil Microbial ◽  
Physico Chemical ◽  
Nematode Population Density ◽  
Significant Enrichment

AbstractChanges in the soil nematofauna community structure were followed in nine millet fields on seven farms in two villages in Senegal during one cropping cycle. Cultivation practices were done by field owners. One plot in each field was divided into two subplots; in one of these, manure (20 t ha-1) was added at sowing. Before the manure input, at mid-cycle and at millet harvest, the structure of the nematode fauna was studied. Soil physico-chemical characteristics, microbial carbon and plant production were measured at sowing and at millet harvest. In the sub-plots where manure was added, millet yield increased by 155%, the mineral nitrogen content of the soil increased by about 45%, while nitrogen flux increased by 150% and microbial biomass by 65%. The significant enrichment of soil by manure led to a 75% increase in total nematode population density at mid-cycle and to a 30% increase at harvest time. The density of opportunistic bacterial-feeding and fungal-feeding nematodes was significantly larger with than without manure. This result is similar to those of comparable studies in temperate areas; however the relative abundance of enrichment opportunists was extremely low with regard to that found under similar conditions in temperate ecosystems. Furthermore, the abundance of the c-p 2 bacterialfeeding nematodes, belonging mainly to the family Cephalobidae, was strongly correlated with soil microbial biomass. The other c-p feeding guilds showed no correlation with nitrogen flux, or soil microbial biomass.

scholarly journals A decade of supraglacial lake volume estimates across a land-terminating margin of the Greenland Ice Sheet

2013 ◽  
Vol 7 (2) ◽  
pp. 1383-1414 ◽  
Author(s):  
A. A. W. Fitzpatrick ◽  
A. L. Hubbard ◽  
J. E. Box ◽  
D. J. Quincey ◽  
D. van As ◽  
...  
Keyword(s):  
Greenland Ice Sheet ◽  
Water Volume ◽  
Strongly Correlated ◽  
Flow Acceleration ◽  
Lake Volume ◽  
Supraglacial Lakes ◽  
Hydrological System ◽  
Storage Buffer ◽  
Optical Satellite Images ◽  
Volume Estimates

Abstract. Supraglacial lakes represent an ephemeral storage buffer for runoff and lead to significant, yet short-lived, episodes of ice-flow acceleration by decanting large fluxes of meltwater and energy into the ice sheet's hydrological system. Here, a field-validated methodology for calculating lake volume is used to quantify storage and drainage across Russell Glacier catchment, west Greenland, from 2002 onwards. Using 502 optical satellite images, water volume at ~200 seasonally occurring lakes was derived from a depth-reflectance relationship, independently calibrated and field-validated against lake bathymetry. Inland expansion of lakes is strongly correlated with air temperature: during the record melt years of 2010 and 2012, lakes formed and drained earlier, attaining their maximum volume 38 and 20 days before the 11 yr mean, as well as occupying a greater area and forming at higher elevations (>1800 m) than previously. Although lakes occupy only 2% of the catchment surface area, they temporarily store up to 13% of the bulk meltwater discharged. Across Russell Glacier, 28% of supraglacial lakes drain rapidly and clustering of such events in space and time suggests a synoptic trigger-mechanism. Furthermore, we find no evidence to support a unifying critical size or depth-dependent drainage threshold hypothesis.

A LA-ICPMS zircon record of magmatic crystallization and compositional alteration in meta-igneous rocks of the eastern Kaapvaal Craton

2021 ◽  
Author(s):  
R. Bolhar ◽  
A. Hofmann ◽  
C.M. Allen ◽  
R. Maas
Keyword(s):  
Trace Elements ◽  
Uncertainty Assessment ◽  
Kaapvaal Craton ◽  
Strongly Correlated ◽  
Time Resolved ◽  
Physico Chemical ◽  
Icp Ms ◽  
Zircon Crystallization ◽  
Element Mobilization ◽  
Chemical Conditions

Abstract Archaean zircons from the Kaapvaal Craton, South Africa, were analyzed by Laser Ablation (LA)-ICP-MS to obtain a coupled record of U-Th-Pb isotope ratios and selected trace elements with the aim to develop insights into physico-chemical conditions during igneous zircon crystallization and subsequent compositional alteration. Four rock samples previously dated by SIMS U-Pb using zircon were selected: 3.56 Ga Ngwane Gneiss, 3.55 Ga Theespruit felsic metavolcanic, 3.50 Ga Steynsdorp Gneiss and 2.98 Ga Nhlangano Gneiss. LA-ICP-MS U-Pb zircon ages agree with published SIMS U-Pb ages within analytical uncertainty. Assessment of the magmatic crystallization histories was based on near-concordant grains, and discordant grains were used to examine post-igneous element mobilization and alteration. Time-resolved laser drilling experiments allowed distinction of concordant and discordant zircon domains, but also revealed systematic changes in REE + Ti geochemistry, U + Th content, discordance and metamictization. Th/U and Zr/Hf, coupled with REE patterns, effectively distinguish compositional zircon types that reflect variable degrees of igneous differentiation and melt compositions. Eu/Eu* values indicate significant feldspar fractionation in some magmas. Averaged crystallization temperatures of magmatic zircons, as derived from the Ti-in-zircon thermometer, define a narrow range of 650 to 750°C for (near-)concordant grains, consistent with general constraints on temperatures at zircon saturation for felsic magmas, and testifying to a closed-system behavior of Ti (and other trace elements). Systematic deviations from primary igneous trace element signatures are strongly correlated with radiation damage. Specifically, Th/U and, to some extent, Zr/Hf decrease, and Ti increases with increasing U (+Th) content and isotopic disturbance (discordance).

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