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Shade and flow effects on ammonia retention in macrophyte-rich streams: implications for water quality [An article from: Environmental Pollution]
Book Details
PublisherElsevier
ISBN / ASINB000RR0FAG
ISBN-13978B000RR0FA2
AvailabilityAvailable for download now
Sales Rank99,999,999
MarketplaceUnited States 🇺🇸
Description
This digital document is a journal article from Environmental Pollution, published by Elsevier in 2004. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.
Description:
Controlled releases of NH"4-N and conservative tracers (Br^- and Cl^-) to five reaches of four streams with contrasting macrophyte communities have shown differing retentions, largely as a result of the way plants interact with stream flow and velocity. First-order constants (k) were 1.0-4.8d^-^1 and retention of NH"4-N was 6-71% of amounts added to each reach. Distance travelled before a 50% reduction in concentration was achieved were 40-450m in three streams under low-flow conditions, and 2400-3800m at higher flows. Retention (%) of NH"4-N can be approximated by a simple function of travel time and k, highlighting the importance of the relationship between macrophytes and stream velocity on nutrient processing. This finding has significant management implications, particularly with respect to restoration of riparian shade. Small streams with predominantly marginal emergent plants are likely to have improved retention of NH"4-N as a result of shading or other means of reducing plant biomass. Streams dominated by submerged macrophytes will have impaired NH"4-N retention if plant biomass is reduced because of reduced contact times between NH"4-N molecules and reactive sites. In these conditions water resource managers should utilise riparian shading in concert with unshaded vegetated reaches to achieve a balance between enhanced in-stream habitat and nutrient processing capacity.
Description:
Controlled releases of NH"4-N and conservative tracers (Br^- and Cl^-) to five reaches of four streams with contrasting macrophyte communities have shown differing retentions, largely as a result of the way plants interact with stream flow and velocity. First-order constants (k) were 1.0-4.8d^-^1 and retention of NH"4-N was 6-71% of amounts added to each reach. Distance travelled before a 50% reduction in concentration was achieved were 40-450m in three streams under low-flow conditions, and 2400-3800m at higher flows. Retention (%) of NH"4-N can be approximated by a simple function of travel time and k, highlighting the importance of the relationship between macrophytes and stream velocity on nutrient processing. This finding has significant management implications, particularly with respect to restoration of riparian shade. Small streams with predominantly marginal emergent plants are likely to have improved retention of NH"4-N as a result of shading or other means of reducing plant biomass. Streams dominated by submerged macrophytes will have impaired NH"4-N retention if plant biomass is reduced because of reduced contact times between NH"4-N molecules and reactive sites. In these conditions water resource managers should utilise riparian shading in concert with unshaded vegetated reaches to achieve a balance between enhanced in-stream habitat and nutrient processing capacity.
