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Nitrate-depleted co...
Nitrate-depleted conditions on the increase in shallow northern European lakes
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- Weyhenmeyer, Gesa A. (författare)
- Uppsala universitet,Limnologi
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Jeppesen, Erik (författare)
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Adrian, Rita (författare)
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visa fler...
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Arvola, Lauri (författare)
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- Blenckner, Thorsten (författare)
- Uppsala universitet,Institutionen för geovetenskaper
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Jakanowski, Thomas (författare)
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Jennings, Eleanor (författare)
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Noges, Peter (författare)
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Noges, Tiina (författare)
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Straile, Dietmar (författare)
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visa färre...
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(creator_code:org_t)
- 2007
- 2007
- Engelska.
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Ingår i: Limnology and Oceanography. - 0024-3590 .- 1939-5590. ; 52:4, s. 1346-1353
- Relaterad länk:
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https://urn.kb.se/re...
Abstract
Ämnesord
Stäng
- We determined relative nitrate-nitrogen (NO3- N) loss rates in 100 north-mid-European lakes from late spring to summer by using the exponential function N-2 5 N-1e(-k)( (t)(2) - (t)(2)), where N-1 and N-2 are NO3- N concentrations at the beginning (t(1)) and the end (t(2)) of the time interval, respectively, and k is the specific NO3- N loss rate. We found that k decreased with increasing lake depth. Adjusting k to the lake depth (k(adj)), we observed that k(adj) was positively related to spring NO3-N concentrations, but this relationship became insignificant at mean lake depths exceeding 12.5 m. A relationship between k(adj) and spring NO3- N concentrations in lakes shallower than 12.5 m implies that changes in spring NO3-N concentrations influence the NO3- N loss rate and thereby summer NO3- N concentrations. Time series from one Estonian, one German, and 14 Swedish lakes shallower than 12.5 m since 1988 revealed that May to August NO3-N concentrations have decreased over time everywhere, and the number of time periods exhibiting a NO3-N depleted condition, i.e., NO3-N levels below 10 mu g L-1, in these lakes has tripled since 1988. We explained the decreasing NO3-N concentrations by a reduction in external nitrogen loading including atmospheric deposition, and by changes in climate. The observed prolongation of NO3- N depleted conditions might be one possible explanation for the increasing occurrence of nitrogen- fixing cyanobacteria in a variety of lake ecosystems.
Ämnesord
- NATURVETENSKAP -- Biologi (hsv//swe)
- NATURAL SCIENCES -- Biological Sciences (hsv//eng)
Nyckelord
- nitrate-depleted
- northern lakes
- relative nitrate-nitogen
- mean lake depth
- denitrification
- Biology
- Biologi
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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Weyhenmeyer, Ges ...
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Jeppesen, Erik
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Adrian, Rita
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Arvola, Lauri
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Blenckner, Thors ...
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Jakanowski, Thom ...
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visa fler...
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Jennings, Eleano ...
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Noges, Peter
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Noges, Tiina
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Straile, Dietmar
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visa färre...
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Limnology and Oc ...
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Uppsala universitet