Change search
ReferencesLink to record
Permanent link

Direct link
Sediment size and nutrients regulate denitrification in a tropical stream
Show others and affiliations
2009 (English)In: Journal of The North American Benthological Society, ISSN 0887-3593, Vol. 28, no 2, 480-490 p.Article in journal (Refereed) Published
Abstract [en]

Landuse changes might alter N cycling in tropical aquatic ecosystems, but understanding of N cycling in tropical streams is limited. We measured actual and potential denitrification rates during the dry season in Rio Las Marias, a 4(th)-order Andean piedmont stream in Venezuela. Our objectives were to describe spatial and temporal variation in denitrification, quantify the effects of nutrient availability and substratum particle size on denitrification, and explore potential effects of anthropogenic sedimentation on denitrification. In 4 experiments, actual and potential denitrification rates ranged from 0 to 160 and from 0 to 740 mu g N(2)O-N m(-2) h(-1), respectively. Rates were distributed approximately log-normally because of spatial variation. During a 1-mo period, actual denitrification rates decreased exponentially from 37 +/- 39 to 5 +/- 7 mu g N(2)O-N m(-2) h(-1) (mean +/- SD), probably because of a decline in water-column NO(3)-N concentration from 41 +/- 14 to 12 +/- 3 mu g NO(3)-N/L. The texture (particle size) of stream substrata markedly affected denitrification rates. Actual rates were low in cobble, gravel, and fine sediments (< 5 mm), but in fine sediments, rates increased in response to addition of excess NO(3)-N and organic C. In a 3-km stream reach, actual (but not potential) denitrification rates increased with the proportion of fine sediments (< 2 mm) in mixed substrata. This increase was nonlinear, and the threshold value occurred at 37% fine particles, above which actual denitrification rates were almost always high. An experiment simulating the effects of anthropogenic sedimentation showed that topsoil inputs resulted in denitrification rates similar to 8x higher than rates in trials where excess NO(3)-N and organic C were supplied. Denitrification is a small but potentially significant sink for available N in this N-limited system. Anthropogenic sedimentation associated with landuse change might significantly increase denitrification rates in streams.

Place, publisher, year, edition, pages
2009. Vol. 28, no 2, 480-490 p.
Keyword [en]
denitrification, stream, nitrogen cycle, tropics, anthropogenic sedimentation, land use
URN: urn:nbn:se:umu:diva-101046DOI: 10.1899/07-157.1ISI: 000266645700019OAI: diva2:796199
Available from: 2015-03-18 Created: 2015-03-18 Last updated: 2015-03-18

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Solomon, Christopher T.Hotchkiss, Erin R.
In the same journal
Journal of The North American Benthological Society

Search outside of DiVA

GoogleGoogle Scholar
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

Altmetric score

Total: 22 hits
ReferencesLink to record
Permanent link

Direct link