3 research outputs found
Influence of transient storage on stream nutrient uptake based on substrata manipulation
12 Páginas ; 5 Figuras ; 3 TablasQuantification of the transient storage zone (As)
has become critical in stream biogeochemical studies
addressed to examine factors controlling nutrient uptake. It
is expected that higher As may enhance the interaction
between nutrients and biota and thus, increase nutrient
uptake. However, results from the literature are controversial.
We hypothesized that besides of the size of As, the
intrinsic physical and biological characteristics of stream
structures that generate As are also relevant for nutrient
uptake. We performed 24 additions of phosphate, ammonium,
and chloride in four reaches of a man-made channel
where we introduced three types of naturally colonized
substrata packs (mud, sand and cobbles) to modify As. We
estimated ammonium and phosphate uptake coefficients in
both the main channel and As using a solute transport
model (OTIS-P) and compared the results among reaches
with different substrata types. The introduction of substrata
packs decreased water velocity and increased As similarly
among treatments. Nutrient uptake coefficients in the main
channel were similar among reaches with different type
substrata packs; however, nutrient uptake coefficients
measured in As differed among them as well as the ratio
between ammonium and phosphorus uptake coefficients inAs, which were 1.6 in reaches with mud packs and 0.02 in
reaches with sand or cobble packs. Results obtained in this
study suggest that the contribution of As in nutrient uptake
not only depends on the size of As but on the type of
materials used to increase As, and thus, have biogeochemical
implications on restoration projects aimed to
modify channel morphology.Financial support was provided by the European Union
through the EURO-LIMPACS project (ref. GOCE-CT-2003-505540,
http://www.eurolimpacs.ucl.ac.uk), by the Spanish Government
through the NICON project (ref. CGL2005-07362-C02), and by the
National Science Foundation (EAR 04-09534 and EAR 08-38338).Peer reviewe