Дисертації з теми "Internal loading of nitrogen and phosphorus"
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Myers, Justin Adam. "Internal loading of nitrogen (N) and phosphorus (P), reduced N forms, and periodic mixing support cyanobacterial harmful algal blooms (HABs) in shallow, eutrophic Honeoye Lake (New York, USA)." Wright State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=wright1622556045440146.
Повний текст джерелаSpears, Bryan M. "Benthic-pelagic nutrient cycling in shallow lakes : investigating the functional role of benthic microalgae." Thesis, University of St Andrews, 2007. http://hdl.handle.net/10023/371.
Повний текст джерелаKoski-Vähälä, Jukka. "Role of resuspension and silicate in internal phosphorus loading." Helsinki : University of Helsinki, 2001. http://ethesis.helsinki.fi/julkaisut/maa/limno/vk/koski-vahala/.
Повний текст джерелаLappalainen, K. M. (K Matti). "Itämeren rehevöitymisen uudistettu diagnoosi ja paradigma." Doctoral thesis, Oulun yliopisto, 2018. http://urn.fi/urn:isbn:9789526219417.
Повний текст джерелаTiivistelmä Itämeri rehevöityy edelleen, vaikka fosforikuormitusta on vähennetty 80 % tavoitellusta. On siis syytä tutkia miksi Itämeren tila ei ole parantunut. Syntyneen ristiriidan ratkaisemiseksi tarkoituksena on etsiä aiemmista tulkinnoista ristiriitoja, korjata ne ja uudistaa tietopohja uudeksi ja toimivammaksi paradigmaksi. Virhetulkintojen tunnistamiseen sovelletaan Popperin falsifikaatiomenettelyn periaatteita. Konsensuksen mukaan ihmisperäinen kuormitus on lähes yksinomainen syy (sinilevä)rehevyyteen. Kuitenkin Vollenweiderin mallin mukaan tehty, hydrologialla painotettu fosforin pintakuormitus on ollut 1970 - 1980-luvuilla vain lievää rehevyyttä edellyttävällä tasolla. Ulkoinen kuormitus ei siten voi olla suurin rehevyyden aiheuttaja. Sinilevärehevyyttä ylläpitävänä päätekijänä on syvävesiin happea tuovien suolavesipulssien toistuvuuden romahtaminen. Siitä syntyneet syvävesien ja -pohjien hapettomuudet aiheuttavat Gotlanninmeressä sekä sisäistä kuormitusta että lisärehevöittävää typen- ja hiilensidontaa. Yhdessä näitä prosesseja nimitetään nyt supernoidankehäksi. Johtopäätöksiä: • Ihmistieteelliset ja ympäristöpoliittiset näkemykset vaikuttavat luonnontieteellisiin tulkintoihin luultua enemmän. • Suolavesipulssien harventuminen on hapettomuus- ja rehevyyskierteen perussyy. • Syvänteiden hapettomuus on kaikkialle negatiivisesti säteilevä keskeistekijä. • Itämeren supernoidankehä on purettava saattamalla syvänteet hapellisiksi. • Hapellisuutta ei voida saada aikaan ulkoisen kuormituksen vähentämisellä. • Jäljelle jäävät siten teknologiset keinot, joista toteutuskelvollisimmalta näyttää Itämeren hapellisimman ja kylmimmän veden pumppaus 30 metrin syvyydestä syvänteisiin, mikä tehostaa myös pulssivesien virtausta syvänteiden pohjalle. Tämä väitöskirja sisältää viisi vallitsevasta paradigmasta poikkeavaa tulosta: 1. Itämerelle on kehitetty rehevyyden uusi diagnoosi ja paradigma, 2. Luonto dominoi Itämeren tilaa, ei ihminen, 3. Typensidonnalla on lisärehevöittävä mekanismi, 4. Itämerelle on kehitetty uusi fosforin sisäkuormituksen laskentamenetelmä, 5. Virtuaalisen fosforikuormituksen laskenta. Ilman Gotlanninmeren syvänteiden hapellisuutta Itämeri on tuomittu pysymään rehevyyden supernoidankehässä, ’kaksinkertaisessa takalukossa’
Ding, Xue. "Characteristics and Applications of Cobalt-Based Phosphate Microelectrodes for Internal Phosphorus Loading." University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1333652128.
Повний текст джерелаGurr, Eric C. "PILOT STUDY OF NUTRIENT LOADING IN A WET DETENTION LAKE." Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2189.
Повний текст джерелаM.S.C.E.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Civil Engineering MSCE
Wilkes, Austin. "Phosphorus Mobility and Speciation Under Dynamic Redox Conditions in Shallow Eutrophic Freshwater Systems." ScholarWorks @ UVM, 2019. https://scholarworks.uvm.edu/graddis/1145.
Повний текст джерелаMeert, Danielle. "Responses of a Louisiana oligohaline marsh plant community to nutrient loading and disturbance." ScholarWorks@UNO, 2008. http://scholarworks.uno.edu/td/890.
Повний текст джерелаJidetorp, Frida. "Sjöars känslighet för klimatförändringar – vilka faktorer påverkar?" Thesis, Uppsala University, Department of Earth Sciences, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-88856.
Повний текст джерелаThe Earths climate is changing at a higher rate, i.e between 1861 and 1994 the annual mean temperature in Scandinavia increased with 0,68º C and according to recent climate models the annual mean temperature is likely to rise with another 3º C during this century.
A warmer climate in many ways is associated with changing conditions for lake ecosystems. An expected higher water temperature and a stronger summer stratification of the water column increases the risk of anoxic conditions at the lake bottom. Thus anoxic conditions are likely to cause a phosphate leakage from the sediment, i.e. a higher internal loading of phosphate.
In this project, the extremely warm summer of 2002 has been used as an example for a possible scenario for a future climate. By comparing levels of phosphorus in the summer of 2002 with a ten-year median value, a phosphorus related sensitivity to climate change has been analyzed for 55 Swedish lakes. This sensitivity has then been related to several parameters of which in particular the lake morphometry and the land use in the catchment of the lake influenced the climatic sensitivity of the lake to climatic change.
Jordens klimat förändras i en allt snabbare takt. Mellan 1861 och 1994 steg årsmedeltemperaturen i Skandinavien med 0,68º C. Enligt aktuella klimatmodeller förväntas årsmedeltemperaturen i Skandinavien öka med ytterligare 3º C det närmaste seklet.
Ett varmare klimat innebär på flera sätt nya förutsättningar för ekosystemen. Genom höjda vattentemperaturer och en starkare stratifikation sommartid ökar risken för syrefria förhållanden i sjöar. Då sedimentet under syrefria förhållanden kan läcka fosfat innebär detta en ökad internbelastning av fosfor.
I detta projekt har den extremt varma sommaren 2002 använts som ett möjligt framtida klimat. Genom att jämföra fosforhalter sommaren 2002 med ett medianvärde för 10 år har den fosforrelaterade känsligheten för klimatförändringar kunnat analyseras för 55 svenska sjöar. Denna känslighet har sedan relaterats till diverse parametrar så som sjöns morfometri och avrinningsområdets sammansättning.
Lynn, Thomas Joseph. "Evaluation and Modeling of Internal Water Storage Zone Performance in Denitrifying Bioretention Systems." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5260.
Повний текст джерелаRandall, Matthew Chambers. "Characterizing the Fate and Mobility of Phosphorus in Utah Lake Sediments." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6915.
Повний текст джерелаLeduc, Meagan. "Seasonal Water Column Dynamics Exert Strong Control On The Chemical Partitioning Of Benthic Phosphorus Pools Of Shallow Eutrophic Freshwater Systems." ScholarWorks @ UVM, 2020. https://scholarworks.uvm.edu/graddis/1183.
Повний текст джерелаAhlgren, Joakim. "Organic Phosphorus Compounds in Aquatic Sediments : Analysis, Abundance and Effects." Doctoral thesis, Uppsala University, Analytical Chemistry, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6701.
Повний текст джерелаPhosphorus (P) is often the limiting nutrient in lacustrine and brackish eco-systems, and enhanced input of P into an aquatic system might therefore negatively impact the environment. Because modern waste water manage-ment have reduced external P input to surface waters, internal P loading from the sediment has become one of the main P sources to aquatic ecosys-tems, in which relatively unknown organic P compounds seem to be more active in P recycling than previously thought.
This thesis focus is on improving analysis methods for organic P com-pounds in lacustrine and brackish sediments, as well as determining which of these compounds might be degraded, mobilized and subsequently recycled to the water column and on what temporal scale this occur. In both lacustrine and brackish environments, the most labile P compound was pyrophosphate, followed by different phosphate diesters. Phosphate monoesters were the least labile organic P compounds and degraded the slowest with sediment depth. In regulated lakes, it was shown that pyrophosphate and polyphos-phate compound groups were most related to lake trophic status, thus indi-cating their involvement in P cycling. This thesis also indicates faster P turn-over in sediment from the brackish environment compared to sediment from the lacustrine environment.
A comparison of organic P extraction procedures showed that pre-extraction with EDTA, and NaOH as main extractant, was most efficient for total P extraction. Using buffered sodium dithionite (BD) as a pre-extractant and NaOH as main extractant was most efficient for extracting the presuma-bly most labile organic P compound groups, pyrophosphate and polyphos-phate. Furthermore, it was determined that organic P compounds associated with humic substances were more recalcitrant than other P compounds, that the BD step used in traditional P fractionation might extract phosphate monoesters, and that NMR is a statistically valid method for quantification of organic P compounds in sediment extracts.
Bakker, Cleo. "Nutrients and biota in a lake system before and after restoration; a data analysis of the Swedish eutrophication case study Växjösjön." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-445066.
Повний текст джерелаFred, Diana. "Internal nutrient loading of the Lake Manitoba south basin." 2013. http://hdl.handle.net/1993/22100.
Повний текст джерелаChan, Wai Sum. "Spatial and temporal features of hydrodynamics and biogeochemistry in Myponga Reservoir, South Australia." Thesis, 2011. http://hdl.handle.net/2440/76100.
Повний текст джерелаThesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2011
Kurek, Martin Roman. "Organic Phosphorus Dynamics and Contributions to Eutrophication in a Shallow, Freshwater Bay." Thesis, 2019. http://hdl.handle.net/1805/20368.
Повний текст джерелаPhosphorus (P) is essential for aquatic life; cycling between both inorganic and organic forms to maintain an ecological balance. Its addition into P-scarce freshwaters, either through terrestrial (external) or sedimentary (internal) loading, may disrupt this balance causing blooms of phytoplankton to flourish, often resulting in harmful environmental and anthropogenic consequences. Accordingly, reduction of external P loading has been commonly implemented with a recent focus on sediment-bound legacy P that is mobilized into the water column during dynamic redox conditions. Mobile P species have been identified as both inorganic and organic, with the former representing the most bioavailable fraction, and the latter serving as a source for labile P in freshwaters when in high demand, particularly during blooms. Missisquoi Bay in Lake Champlain, VT experiences harmful cyanobacterial blooms driven by internal P loading and has been the target of numerous geochemical and hydrological studies. This thesis describes a high-resolution investigation of both the organic P and organic matter compositions of the bay with respect to mobility, reactivity, and bioavailability using Fourier Transform-Ion Cyclotron Mass Spectrometry (FT-ICR MS). Sediment from Missisquoi Bay was extracted with a diverse set of reagents, resulting in fractionation of both organic matter and organic P, and illustrating the distribution of various labile and recalcitrant compounds. Many of these molecules are associated with porewater or easily extractable mineral surfaces providing a link to the benthic organic matter and phosphorus fractions available to microorganisms. Additionally, the organic chemistry of the bay was investigated seasonally from May 2017 to January 2018 revealing biological processing from the spring runoff season through the post-bloom summer season. The transition from late summer to under ice conditions in winter was less severe with a higher commonality between both organic matter and organic P compounds, suggesting reduced biological and abiotic degradation. Moreover, short-term anoxic incubations of sediment cores from each season revealed the presence of diverse organic signatures from sorption processes, and a significant contribution of benthic microbial activity to the benthic organic geochemistry.
Rodgers, Lisa. "Synthesis of Water Quality Data and Modeling Non-Point Loading in Four Coastal B.C. Watersheds: Implications for Lake and Watershed Health and Management." Thesis, 2015. http://hdl.handle.net/1828/6999.
Повний текст джерелаGraduate