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Oxygen and its impact on nitrification rates in aquatic sediments

Liesirova, Tina LU (2016) In Dissertations in Geology at Lund University GEOL01 20161
Department of Geology
Abstract (Swedish)
Eutrofiering det oönskade fenomenet av hög näringstillförsel i ett akvatiskt system, är för det mesta ett resultat av mänsklig påverkan: industriellt och urbant avloppsvatten, avrinning av gödningsmedel från odlad mark, och förbränning av fossila bränslen. Studien av de främsta faktorerna som bidrar till eutrofiering (t. ex. variationer i kvävets kretslopp), är viktigt för förståelsen av dess negativa påverkan på miljön och hur man kan motverka det. Olika miljöparametrar påverkar effektiviteten av delprocesser i kvävets kretslopp. Forskning av Jianlong och Ning (2004) föreslår att hypoxiska förhållanden är mer gynnsamma för nitrifiering än normoxiska förhållanden. För att testa denna hypotes hämtades akvatiska sediment från Roskilde... (More)
Eutrofiering det oönskade fenomenet av hög näringstillförsel i ett akvatiskt system, är för det mesta ett resultat av mänsklig påverkan: industriellt och urbant avloppsvatten, avrinning av gödningsmedel från odlad mark, och förbränning av fossila bränslen. Studien av de främsta faktorerna som bidrar till eutrofiering (t. ex. variationer i kvävets kretslopp), är viktigt för förståelsen av dess negativa påverkan på miljön och hur man kan motverka det. Olika miljöparametrar påverkar effektiviteten av delprocesser i kvävets kretslopp. Forskning av Jianlong och Ning (2004) föreslår att hypoxiska förhållanden är mer gynnsamma för nitrifiering än normoxiska förhållanden. För att testa denna hypotes hämtades akvatiska sediment från Roskilde Fjorden I Danmark den 5:e och den 26:e April 2016 (prover apr5, apr26) så att variationer i nitrifieringen beroende på skillnader i syre mängden kunde fastställas. Dessutom, gjordes en jämförelse mellan olika prover för att se om signifikanta skillnader kunde påträffas beroende på vilket datum proverna hämtades. Nitrifieringshastigheten av prov apr5 (0-1 cm djup; 1-2 cm djup) och apr26 (0-2 cm djup) fastställdes genom att mäta koncentrationerna av NOX (NO2- och NO3-) med hjälp av en spektrofotometer. Apr5 delprover mättes två gånger (t0h, t24h), medan prov apr26 mättes fem gånger (t0h, t4h, t8h, t16h, t23h). Dessutom behandlades prov apr26 antingen med luft för att generera normoxiska förhållanden, eller med kväve (gas) för att generara hypoxiska och anoxiska förhållanden. Resultaten från apr5 visar högsta NOX hastighetsvärden på 1-2 cm djup, under OPD (2.7 mm). Resultaten från apr26 under normoxiska/hypoxiska/anoxiska behandlingar visar på att hypoxiska förhållanden är mer gynnsamma för nitrifieringsprocesser. Trots att apr26 proven hade hypoxiska bentiska förhållanden, så var nitrifieringshastigheterna lägre än för apr5. Det är möjligt att ytterligare parametrar så som pH och sulfider kan ha bidragit till den förhållandevis låga nitrifieringshastigheten för apr26, trots den hypoxiska bentiska miljön. (Less)
Abstract
Eutrophication, the undesired phenomenon of high nutrient loads in an aquatic system, is mostly caused by human impact: industrial and urban waste water discharge, run-off of fertilizers from agricultural use, and combustion of fuels. The study of eutrophications' main participants such as the nitrogen cycle, are necessary to prevent it. Environmental parameters have an impact onto the effectivity of the subprocesses of the nitrogen cycle. Research by Jianlong and Ning (2004) suggests hypoxic conditions to be more favorable for nitrification than normoxic ones. In order to test this hypothesis aquatic sediments from the Roskilde Fjord in Denmark were collected on the 5th and the 26th of April 2016 (apr5, apr26) to determine their... (More)
Eutrophication, the undesired phenomenon of high nutrient loads in an aquatic system, is mostly caused by human impact: industrial and urban waste water discharge, run-off of fertilizers from agricultural use, and combustion of fuels. The study of eutrophications' main participants such as the nitrogen cycle, are necessary to prevent it. Environmental parameters have an impact onto the effectivity of the subprocesses of the nitrogen cycle. Research by Jianlong and Ning (2004) suggests hypoxic conditions to be more favorable for nitrification than normoxic ones. In order to test this hypothesis aquatic sediments from the Roskilde Fjord in Denmark were collected on the 5th and the 26th of April 2016 (apr5, apr26) to determine their nitrification rates in differing oxygen environments. In addition, the samples were compared to see if there was a significant contrast between the dates of sample retrieval. The nitrification rates of apr5 (0-1cm depth; 1-2cm depth) and apr26 (0-2cm depth) were established by measuring the NOX (NO2- and NO3-) concentrations with help of a spectrophotometer. Apr5 samples were measured twice (t0h, t24h), whereas the apr26 sediments were measured five times (t0h, t4h, t8h, t16h, t23h). Furthermore, the apr26 samples were treated either with air to generate normoxic conditions, or with nitrogen gas to generate hypoxic and anoxic conditions. The results from apr5 show highest NOX rates in 1-2cm depth, beneath the OPD (2.7mm). The results from apr26 under normoxic/hypoxic/anoxic treatment suggest hypoxic conditions to be more favorable for nitrifying processes. Despite apr26 samples having had hypoxic benthic conditions, nitrification rates were lower than from apr5. It is likely the influence of additional parameters such pH and sulfides to be responsible for the comparably low nitrification rates from apr26, despite the hypoxic benthic environment. (Less)
Popular Abstract
Eutrophication is a natural phenomenom of high nutrient loads in an ecosystem. In aquatic environments eutrophication has often a damaging effect, which leads in the worst case to the mass extinction of organisms. One of the main drivers, which participates in the process of eutrophication is the nitrogen cycle. The nitrogen cycle is a set of processes and is able to convert atmospheric nitrogen into inorganic compounds which then are absorbed by organisms. Inorganic nitrogen is used a s energy sources and for building up important proteins. The converting processes in the cycle are nitrogen fixation, assimilation, ammonification,
nitrification, and denitrification. Different microbial groups are performing these converting processes,... (More)
Eutrophication is a natural phenomenom of high nutrient loads in an ecosystem. In aquatic environments eutrophication has often a damaging effect, which leads in the worst case to the mass extinction of organisms. One of the main drivers, which participates in the process of eutrophication is the nitrogen cycle. The nitrogen cycle is a set of processes and is able to convert atmospheric nitrogen into inorganic compounds which then are absorbed by organisms. Inorganic nitrogen is used a s energy sources and for building up important proteins. The converting processes in the cycle are nitrogen fixation, assimilation, ammonification,
nitrification, and denitrification. Different microbial groups are performing these converting processes, however the process-rates are not continuously stable, because the nitrogen cycle and its participants are greatly influenced by alternating environmental conditions. These environmental conditions are amongst others parameters like pH, salinity, temperature and oxygen.
For nitrification oxygen holds a significant importance, because it performs under oxic conditions. However recent studies imply rather hypoxic than normoxic conditions are more favorable for nitrifying
processes. By understanding the details of these complex nitrifying processes and implementing effective sewage regulations accordingly, risky accumulations of nitrogen concentrations in waters could be avoided, which in itself would avoid eutrophication.
The aim of this bachelor thesis is the study and comparison of production rates of nitrifying processes under differing oxygen conditions in aquatic sediments taken from the Roskilde Fjord in Denmark. (Less)
Please use this url to cite or link to this publication:
author
Liesirova, Tina LU
supervisor
organization
course
GEOL01 20161
year
type
M2 - Bachelor Degree
subject
keywords
normoxic, hypoxic, eutrophication, nitrification, Roskilde Fjord
publication/series
Dissertations in Geology at Lund University
report number
468
language
English
id
8880563
date added to LUP
2016-06-16 11:43:50
date last changed
2016-06-16 11:43:50
@misc{8880563,
  abstract     = {Eutrophication, the undesired phenomenon of high nutrient loads in an aquatic system, is mostly caused by human impact: industrial and urban waste water discharge, run-off of fertilizers from agricultural use, and combustion of fuels. The study of eutrophications' main participants such as the nitrogen cycle, are necessary to prevent it. Environmental parameters have an impact onto the effectivity of the subprocesses of the nitrogen cycle. Research by Jianlong and Ning (2004) suggests hypoxic conditions to be more favorable for nitrification than normoxic ones. In order to test this hypothesis aquatic sediments from the Roskilde Fjord in Denmark were collected on the 5th and the 26th of April 2016 (apr5, apr26) to determine their nitrification rates in differing oxygen environments. In addition, the samples were compared to see if there was a significant contrast between the dates of sample retrieval. The nitrification rates of apr5 (0-1cm depth; 1-2cm depth) and apr26 (0-2cm depth) were established by measuring the NOX (NO2- and NO3-) concentrations with help of a spectrophotometer. Apr5 samples were measured twice (t0h, t24h), whereas the apr26 sediments were measured five times (t0h, t4h, t8h, t16h, t23h). Furthermore, the apr26 samples were treated either with air to generate normoxic conditions, or with nitrogen gas to generate hypoxic and anoxic conditions. The results from apr5 show highest NOX rates in 1-2cm depth, beneath the OPD (2.7mm). The results from apr26 under normoxic/hypoxic/anoxic treatment suggest hypoxic conditions to be more favorable for nitrifying processes. Despite apr26 samples having had hypoxic benthic conditions, nitrification rates were lower than from apr5. It is likely the influence of additional parameters such pH and sulfides to be responsible for the comparably low nitrification rates from apr26, despite the hypoxic benthic environment.},
  author       = {Liesirova, Tina},
  keyword      = {normoxic,hypoxic,eutrophication,nitrification,Roskilde Fjord},
  language     = {eng},
  note         = {Student Paper},
  series       = {Dissertations in Geology at Lund University},
  title        = {Oxygen and its impact on nitrification rates in aquatic sediments},
  year         = {2016},
}