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Changes in amorphous silica sequestration with eutrophication of riverine impoundments

Triplett, Laura D.; Engstrom, Daniel R. and Conley, Daniel LU (2012) In Biogeochemistry 108(1-3). p.413-427
Abstract
The effect of eutrophication on particulate amorphous silica (ASi) sequestration was isolated and quantified in Lake St. Croix and Lake Pepin, two natural, human-impacted impoundments of the upper Mississippi River. In contrast to impoundments behind engineered dams, where silica (Si) fluxes may be changed by various aspects of dam construction, these two riverine lakes have long (9,000+ years) sedimentary sequences that record the entire span of cultural eutrophication and the resulting silica sequestration. The concentrations of dissolved silicate (DSi) and ASi in the lake inflows were measured for 1 year to obtain the total flux of bioavailable silica (TSib = DSi + ASi) to each impoundment. Historical rates of Si sequestration in each... (More)
The effect of eutrophication on particulate amorphous silica (ASi) sequestration was isolated and quantified in Lake St. Croix and Lake Pepin, two natural, human-impacted impoundments of the upper Mississippi River. In contrast to impoundments behind engineered dams, where silica (Si) fluxes may be changed by various aspects of dam construction, these two riverine lakes have long (9,000+ years) sedimentary sequences that record the entire span of cultural eutrophication and the resulting silica sequestration. The concentrations of dissolved silicate (DSi) and ASi in the lake inflows were measured for 1 year to obtain the total flux of bioavailable silica (TSib = DSi + ASi) to each impoundment. Historical rates of Si sequestration in each lake were determined using ASi burial in multiple sediment cores and modeled estimates of historical TSib fluxes. The Si trapping efficiency of each lake was found to have increased exponentially with cultural eutrophication (estimated two- to fivefold increase in Lake St. Croix and 9- to 16-fold increase in Lake Pepin over the last 100 years), indicating the degree to which eutrophication of impoundments can reduce silica export to downstream coastal and marine ecosystems. Because these two lakes presently exhibit different degrees of eutrophication, together they depict a relationship between phosphorus concentration and Si trapping efficiency that may be applied to other impoundments, including human-made reservoirs. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Biogenic silica, Trapping efficiency, Mississippi River, Eutrophication, Riverine lake
in
Biogeochemistry
volume
108
issue
1-3
pages
413 - 427
publisher
Springer
external identifiers
  • wos:000300659300027
  • scopus:84857626429
ISSN
1573-515X
DOI
10.1007/s10533-011-9608-9
project
BECC
language
English
LU publication?
yes
id
5bef5c56-43e8-4a46-a9be-b8ea5f06d4b6 (old id 2378744)
date added to LUP
2012-03-27 14:56:49
date last changed
2017-09-24 03:13:16
@article{5bef5c56-43e8-4a46-a9be-b8ea5f06d4b6,
  abstract     = {The effect of eutrophication on particulate amorphous silica (ASi) sequestration was isolated and quantified in Lake St. Croix and Lake Pepin, two natural, human-impacted impoundments of the upper Mississippi River. In contrast to impoundments behind engineered dams, where silica (Si) fluxes may be changed by various aspects of dam construction, these two riverine lakes have long (9,000+ years) sedimentary sequences that record the entire span of cultural eutrophication and the resulting silica sequestration. The concentrations of dissolved silicate (DSi) and ASi in the lake inflows were measured for 1 year to obtain the total flux of bioavailable silica (TSib = DSi + ASi) to each impoundment. Historical rates of Si sequestration in each lake were determined using ASi burial in multiple sediment cores and modeled estimates of historical TSib fluxes. The Si trapping efficiency of each lake was found to have increased exponentially with cultural eutrophication (estimated two- to fivefold increase in Lake St. Croix and 9- to 16-fold increase in Lake Pepin over the last 100 years), indicating the degree to which eutrophication of impoundments can reduce silica export to downstream coastal and marine ecosystems. Because these two lakes presently exhibit different degrees of eutrophication, together they depict a relationship between phosphorus concentration and Si trapping efficiency that may be applied to other impoundments, including human-made reservoirs.},
  author       = {Triplett, Laura D. and Engstrom, Daniel R. and Conley, Daniel},
  issn         = {1573-515X},
  keyword      = {Biogenic silica,Trapping efficiency,Mississippi River,Eutrophication,Riverine lake},
  language     = {eng},
  number       = {1-3},
  pages        = {413--427},
  publisher    = {Springer},
  series       = {Biogeochemistry},
  title        = {Changes in amorphous silica sequestration with eutrophication of riverine impoundments},
  url          = {http://dx.doi.org/10.1007/s10533-011-9608-9},
  volume       = {108},
  year         = {2012},
}