Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Quantitative Understanding and Prediction of Lake Eutrophication
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
2008 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Many lakes around the world have been exposed to increased nutrient input from anthropogenic sources such as sewage discharge and runoff from fertilised agricultural areas. This has led to eutrophication, manifested as intensified algal blooms, murky waters, oxygen depleted lake bottoms, and alterations of considerable parts of the foodweb. However, many of these lakes have also recovered, due to improved nutrient abatement techniques and to an improved quantitative scientific understanding of eutrophication and its causes. General, predictive models have played a crucial role in the latter development, as they have made it possible to quantitatively assess expected ecosystem changes from various planned actions against eutrophication.

The present thesis has been aimed at improving the domain of validity and predictive power of a general, dynamic total phosphorus (TP) model (LakeMab) and to provide the basis for constructing a similar model for total nitrogen (TN). Among the findings in the thesis is that dissolved nitrogen gas is probably always available in excess for nitrogen fixation and nitrogen modelling in eutrophication contexts. Two papers have laid the ground for improved nutrient modelling in calcareous lakes, where sedimentation is particularly pronounced. Static models for predicting concentrations of particulate phosphorus, nitrogen, and organic carbon have been presented that may be incorporated into sedimentation algorithms in dynamic nutrient models. Boundary conditions for various flux algorithms have made it possible to greatly expand the domain of LakeMab for TP. The typical uncertainty of TP concentration values is 17% when predicted with LakeMab, whereas the uncertainty in predictions using older, static models is about twice as high.

LakeMab may be very useful for resolving practical issues such as predicting climate-induced eutrophication and drawing up operational guidelines for achieving good water quality as prescribed by, e.g., the European Water Framework Directive.

Place, publisher, year, edition, pages
Uppsala: Universitetsbiblioteket , 2008. , p. 38
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 415
National Category
Ecology
Identifiers
URN: urn:nbn:se:uu:diva-8593ISBN: 978-91-554-7143-9 (print)OAI: oai:DiVA.org:uu-8593DiVA, id: diva2:171698
Public defence
2008-04-18, Hambergssalen, Institutionen för geovetenskaper, Villavägen 16, Uppsala, 10:00 (English)
Opponent
Supervisors
Available from: 2008-03-13 Created: 2008-03-13 Last updated: 2009-03-30Bibliographically approved
List of papers
1. Can nitrogen gas be deficient for nitrogen fixation in lakes?
Open this publication in new window or tab >>Can nitrogen gas be deficient for nitrogen fixation in lakes?
2007 (English)In: Ecological Modelling, ISSN 0304-3800, E-ISSN 1872-7026, Vol. 202, no 3-4, p. 362-372Article in journal (Refereed) Published
Abstract [en]

Severe nitrogen gas (N2) depletion in lakes may have implications for N2 fixation and for model structures describing the nitrogen (N) cycle. To determine whether this is likely to occur, we first reviewed the general processes influencing the N2 cycle in lakes. Second, we empirically analysed N2 concentrations in various stations and depths of Lake Erken, Sweden during the beginning and the end of the summer stratification period of 2004. Overall, no significant deviations from N2 saturation from any stations or depths were observed during the study period. Third, we developed a simple, one-box gas model to investigate possible effects on lake water from processes described in the literature that affect the N2 concentration. Simulations indicated that bottom waters and other isolated water bodies may show strong deviations from N2 saturation during certain conditions differing from those during summers in Lake Erken. Simulated surface waters were always N2 saturated in all types of lakes where the water column was in direct contact with the air. We quantified all probable fluxes, showed that the N2 concentration in surface waters vastly exceeds the half-saturation constant for N uptake by phytoplankton, and concluded that it is unlikely that N2 fixation is ever limited by the N2 concentration. Modellers of lake eutrophication may regard N2 as being available in excess.

Keywords
Nitrogen gas, Lakes, Denitrification, Nitrogen fixation, Methane, Seepage, Half-saturation, Nutrient modelling
National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-96948 (URN)10.1016/j.ecolmodel.2006.10.025 (DOI)000245517000010 ()
Available from: 2008-03-13 Created: 2008-03-13 Last updated: 2017-12-14Bibliographically approved
2. The influence of calcium on the chlorophyll–phosphorus relationship and lake Secchi depths
Open this publication in new window or tab >>The influence of calcium on the chlorophyll–phosphorus relationship and lake Secchi depths
2005 In: Hydrobiologia, ISSN 0018-8158, Vol. 537, no 1-3, p. 111-123Article in journal (Refereed) Published
Identifiers
urn:nbn:se:uu:diva-96949 (URN)
Available from: 2008-03-13 Created: 2008-03-13Bibliographically approved
3. Predicting particulate pools of nitrogen, phosphorus and organic carbon in lakes
Open this publication in new window or tab >>Predicting particulate pools of nitrogen, phosphorus and organic carbon in lakes
2007 (English)In: Aquatic Sciences, ISSN 1015-1621, E-ISSN 1420-9055, Vol. 69, no 4, p. 484-494Article in journal (Refereed) Published
Abstract [en]

The variation between lakes with respect to concentrations of particulate nutrient pools was studied in 126 Norwegian lakes covering a wide range in lake-specific properties. Particulate phosphorus (P) always constituted close to 60% of total P (TP) concentrations. Particulate nitrogen (N) and organic carbon (C) concentrations, on the other hand, were sensitive to several lake characteristics, particularly to TP concentrations. Through optimisation procedures and multivariate regression, the present study presents general empirical models for predicting particulate nutrient concentrations. Furthermore, significant trend shifts in the relationships between TP vs. particulate N and TP vs. particulate organic C were observed at TP = 6 mu g l(-1) and TP = 80 mu g l(-1), suggesting non-linearities in these relationships along the TP gradient. A trend shift in the TP vs. chlorophyll relationship was observed at TP = 90. Taking such non-linearities into account may decrease the uncertainty in predicting particulate N, particulate organic C and chlorophyll.

Keywords
particles, trend shifts, nutrients
National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-96950 (URN)10.1007/s00027-007-0914-1 (DOI)000251878800005 ()
Available from: 2008-03-13 Created: 2008-03-13 Last updated: 2017-12-14Bibliographically approved
4. A dynamic mass-balance model for phosphorus in lakes with a focus on criteria for applicability and boundary conditions
Open this publication in new window or tab >>A dynamic mass-balance model for phosphorus in lakes with a focus on criteria for applicability and boundary conditions
2008 (English)In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 187, no 1-4, p. 119-147Article in journal (Refereed) Published
Abstract [en]

This paper presents an improved version of a general, process-based mass-balance model (LakeMab/LEEDS) for phosphorus in entire lakes (the ecosystem scale). The focus in this work is set on the boundary conditions, i.e., the domain of the model, and critical tests to reveal those boundary conditions using data from a wide limnological range. The basic structure of the model, and many key equations have been presented and motivated before, but this work presents several new developments. The LakeMab-model is based on ordinary differential equations regulating inflow, outflow and internal fluxes and the temporal resolution is one month to reflect seasonal variations. The model consists of four compartments: surface water, deep water, sediment on accumulation areas and sediment on areas of erosion and transportation. The separation between the surface-water layer and the deep-water layer is not done from water temperature data, but from sedimentological criteria (from the theoretical wave base, which regulates where wind/wave-induced resuspension of fine sediments occurs). There are algorithms for processes regulating internal fluxes and internal loading, e.g., sedimentation, resuspension, diffusion, mixing and burial. Critical model tests were made using data from 41 lakes of very different character and the results show that the model could predict mean monthly TP-concentrations in water very well (generally within the uncertainty bands given by the empirical data). The model is even easier to apply than the well-known OECD and Vollenweider models due to more easily accessed driving variables.

National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:uu:diva-96951 (URN)10.1007/s11270-007-9502-1 (DOI)000251322200011 ()
Available from: 2010-06-02 Created: 2008-03-13 Last updated: 2017-12-14Bibliographically approved
5. A comparison of predictive phosphorus load-concentration models for lakes
Open this publication in new window or tab >>A comparison of predictive phosphorus load-concentration models for lakes
2007 (English)In: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, Vol. 10, no 7, p. 1084-1099Article in journal (Refereed) Published
Abstract [en]

Lake models that predict phosphorus (P) concentrations from P-loading have provided important knowledge enabling successful restoration of many eutrophic lakes during the last decades. However, the first-generation (static) models were rather imprecise and some nutrient abatement programs have therefore produced disappointingly modest results. This study compares 12 first-generation models with three newer ones. These newer models are dynamic (time-dependent), and general in the sense that they work without any further calibration for lakes from a wide limnological domain. However, static models are more accessible to non-specialists. Predictions of P concentrations were compared with empirical long-term data from a multi-lake survey, as well as to data from transient conditions in six lakes. Dynamic models were found to predict P concentrations with much higher certainty than static models. One general dynamic model, LakeMab, works for both deep and shallow lakes and can, in contrast to static models, predict P fluxes and particulate and dissolved P, both in surface waters and deep waters. PCLake, another general dynamic model, has advantages that resemble those of LakeMab, except that it needs three or four more input variables and is only valid for shallow lakes.

Keywords
eutrophication, phosphorus, lakes, fluxes, predictive power, modelling
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:uu:diva-96952 (URN)10.1007/s10021-007-9078-z (DOI)000251224000003 ()
Available from: 2008-03-13 Created: 2008-03-13 Last updated: 2017-12-14Bibliographically approved

Open Access in DiVA

fulltext(1275 kB)1253 downloads
File information
File name FULLTEXT01.pdfFile size 1275 kBChecksum MD5
bc53e504e2aaa7bdf074293b6a0f3ae6d318e11bab82769a104a2813f3b6bc371b7a054f
Type fulltextMimetype application/pdf
cover(420 kB)57 downloads
File information
File name COVER01.pdfFile size 420 kBChecksum MD5
b1aca0d0de4f70423022e12e7425b590791862184ed00841ac1d5d95cb4994b86445e27b
Type coverMimetype application/pdf
Buy this publication >>

By organisation
Department of Earth Sciences
Ecology

Search outside of DiVA

GoogleGoogle Scholar
Total: 1253 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 2624 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf