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Global importance, patterns, and controls of dissolved silica retention in lakes and reservoirs

Harrison, John A.; Frings, Patrick LU ; Beusen, Arthur H. W.; Conley, Daniel LU and McCrackin, Michelle L. (2012) In Global Biogeochemical Cycles 26. p.2037-2037
Abstract
Lentic water bodies (lakes and reservoirs) offer favorable conditions for silica (SiO2) burial in sediments. Recent global estimates suggest that (1) lentic SiO2 trapping is a globally important SiO2 flux, and (2) through reservoir construction, humans have dramatically altered river dissolved SiO2 (DSi) transport and coastal DSi delivery. However, regional to global scale patterns and controls of DSi removal in lentic systems are poorly constrained. Here we use 27 published lake and reservoir DSi budgets to develop insights into patterns and controls of lentic DSi retention and to develop a new, spatially explicit, global model of lentic DSi removal called SiRReLa (Silica Retention in Reservoirs and Lakes). In our analysis, lentic DSi... (More)
Lentic water bodies (lakes and reservoirs) offer favorable conditions for silica (SiO2) burial in sediments. Recent global estimates suggest that (1) lentic SiO2 trapping is a globally important SiO2 flux, and (2) through reservoir construction, humans have dramatically altered river dissolved SiO2 (DSi) transport and coastal DSi delivery. However, regional to global scale patterns and controls of DSi removal in lentic systems are poorly constrained. Here we use 27 published lake and reservoir DSi budgets to develop insights into patterns and controls of lentic DSi retention and to develop a new, spatially explicit, global model of lentic DSi removal called SiRReLa (Silica Retention in Reservoirs and Lakes). In our analysis, lentic DSi removal (kg SiO2 yr(-1)) was significantly and positively related to DSi loading (P < 0.0001; r(2) = 0.98), and DSi removal efficiency was significantly and positively related to water residence time (P < 0.0001; r(2) = 0.68). In addition, DSi settling rates were, on average, 6.5-fold higher in eutrophic systems than in non-eutrophic systems (median settling velocities: 11.1 and 1.7 m yr(-1) for eutrophic and non-eutrophic systems, respectively; P < 0.01). SiRReLa, which incorporates these insights, performed quite well in predicting both total DSi removal (kg SiO2 yr(-1); Nash Sutcliffe Efficiency (N.S.E) = 0.88) and DSi removal efficiency (% Si removed; N.S.E. = 0.75), with no detectable bias in the model. Global application of SiRReLa confirms that lentic systems are important sinks for DSi, removing 89.1 Tg DSi yr(-1) from watersheds globally, roughly 19-38% of all DSi inputs to surface waters. Small lakes and reservoirs (<50 km(2)) were critical in the analysis, retaining 81% (72 Tg DSi yr(-1)) of the globally retained total. Furthermore, although reservoirs occupy just 6% of the global lentic surface area, they retained approximately 35% of the total DSi removed by lentic systems. Regional hot spots for lentic DSi removal were identified and imply that lentic systems can remove the vast majority of DSi across a large fraction of Earth's land surface. Finally, a sensitivity analysis indicates that future improvements in DSi trapping and transport models should focus on improving estimates of DSi input to surface waters. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Global Biogeochemical Cycles
volume
26
pages
2037 - 2037
publisher
American Geophysical Union
external identifiers
  • wos:000305993100001
  • scopus:84863431579
ISSN
0886-6236
DOI
10.1029/2011GB004228
project
BECC
language
English
LU publication?
yes
id
99b6316d-16b6-428e-85cf-53a0a8c97d00 (old id 3001539)
date added to LUP
2012-08-21 11:05:33
date last changed
2017-09-24 04:07:39
@article{99b6316d-16b6-428e-85cf-53a0a8c97d00,
  abstract     = {Lentic water bodies (lakes and reservoirs) offer favorable conditions for silica (SiO2) burial in sediments. Recent global estimates suggest that (1) lentic SiO2 trapping is a globally important SiO2 flux, and (2) through reservoir construction, humans have dramatically altered river dissolved SiO2 (DSi) transport and coastal DSi delivery. However, regional to global scale patterns and controls of DSi removal in lentic systems are poorly constrained. Here we use 27 published lake and reservoir DSi budgets to develop insights into patterns and controls of lentic DSi retention and to develop a new, spatially explicit, global model of lentic DSi removal called SiRReLa (Silica Retention in Reservoirs and Lakes). In our analysis, lentic DSi removal (kg SiO2 yr(-1)) was significantly and positively related to DSi loading (P &lt; 0.0001; r(2) = 0.98), and DSi removal efficiency was significantly and positively related to water residence time (P &lt; 0.0001; r(2) = 0.68). In addition, DSi settling rates were, on average, 6.5-fold higher in eutrophic systems than in non-eutrophic systems (median settling velocities: 11.1 and 1.7 m yr(-1) for eutrophic and non-eutrophic systems, respectively; P &lt; 0.01). SiRReLa, which incorporates these insights, performed quite well in predicting both total DSi removal (kg SiO2 yr(-1); Nash Sutcliffe Efficiency (N.S.E) = 0.88) and DSi removal efficiency (% Si removed; N.S.E. = 0.75), with no detectable bias in the model. Global application of SiRReLa confirms that lentic systems are important sinks for DSi, removing 89.1 Tg DSi yr(-1) from watersheds globally, roughly 19-38% of all DSi inputs to surface waters. Small lakes and reservoirs (&lt;50 km(2)) were critical in the analysis, retaining 81% (72 Tg DSi yr(-1)) of the globally retained total. Furthermore, although reservoirs occupy just 6% of the global lentic surface area, they retained approximately 35% of the total DSi removed by lentic systems. Regional hot spots for lentic DSi removal were identified and imply that lentic systems can remove the vast majority of DSi across a large fraction of Earth's land surface. Finally, a sensitivity analysis indicates that future improvements in DSi trapping and transport models should focus on improving estimates of DSi input to surface waters.},
  author       = {Harrison, John A. and Frings, Patrick and Beusen, Arthur H. W. and Conley, Daniel and McCrackin, Michelle L.},
  issn         = {0886-6236},
  language     = {eng},
  pages        = {2037--2037},
  publisher    = {American Geophysical Union},
  series       = {Global Biogeochemical Cycles},
  title        = {Global importance, patterns, and controls of dissolved silica retention in lakes and reservoirs},
  url          = {http://dx.doi.org/10.1029/2011GB004228},
  volume       = {26},
  year         = {2012},
}