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New insights on resource stoichiometry: assessing availability of carbon, nitrogen, and phosphorus to bacterioplankton

Soares, Ana LU ; Bergström, Ann-Kristin; Sponseller, Ryan A.; Marchlewska Moberg, Joanna LU ; Giesler, Reiner; Kritzberg, Emma LU ; Jansson, Mats and Berggren, Martin LU (2017) In Biogeosciences 14(6). p.1527-1539
Abstract
Boreal lake and river ecosystems receive large quantities of organic nutrients and carbon (C) from their catchments. How bacterioplankton respond to these inputs is not well understood, in part because we base our understanding and predictions on total pools, yet we know little about the stoichiometry of bioavailable elements within organic matter. We designed bioassays with the purpose of exhausting the pools of readily bioavailable dissolved organic carbon (BDOC), bioavailable dissolved nitrogen (BDN), and bioavailable dissolved phosphorus (BDP) as fast as possible. Applying the method in four boreal lakes at base-flow conditions yielded concentrations of bioavailable resources in the range 105–693 µg C L−1 for BDOC (2 % of initial total... (More)
Boreal lake and river ecosystems receive large quantities of organic nutrients and carbon (C) from their catchments. How bacterioplankton respond to these inputs is not well understood, in part because we base our understanding and predictions on total pools, yet we know little about the stoichiometry of bioavailable elements within organic matter. We designed bioassays with the purpose of exhausting the pools of readily bioavailable dissolved organic carbon (BDOC), bioavailable dissolved nitrogen (BDN), and bioavailable dissolved phosphorus (BDP) as fast as possible. Applying the method in four boreal lakes at base-flow conditions yielded concentrations of bioavailable resources in the range 105–693 µg C L−1 for BDOC (2 % of initial total DOC), 24–288 µg N L−1 for BDN (31 % of initial total dissolved nitrogen), and 0.2–17 µg P L−1 for BDP (49 % of initial total dissolved phosphorus). Thus, relative bioavailability increased from carbon (C) to nitrogen (N) to phosphorus (P). We show that the main fraction of bioavailable nutrients is organic, representing 80 % of BDN and 61 % of BDP. In addition, we demonstrate that total C : N and C : P ratios are as much as 13-fold higher than C : N and C : P ratios for bioavailable resource fractions. Further, by applying additional bioavailability measurements to seven widely distributed rivers, we provide support for a general pattern of relatively high bioavailability of P and N in relation to C. Altogether, our findings underscore the poor availability of C for support of bacterial metabolism in boreal C-rich freshwaters, and suggest that these ecosystems are very sensitive to increased input of bioavailable DOC. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biogeosciences
volume
14
issue
6
pages
1527 - 1539
publisher
Copernicus Publications
external identifiers
  • scopus:85016251156
  • wos:000398193100004
ISSN
1726-4189
DOI
10.5194/bg-14-1527-2017
language
English
LU publication?
yes
id
b6f07a46-ebcb-4bab-9cea-0ee9996dbf24
date added to LUP
2017-03-24 13:08:58
date last changed
2018-01-07 11:57:00
@article{b6f07a46-ebcb-4bab-9cea-0ee9996dbf24,
  abstract     = {Boreal lake and river ecosystems receive large quantities of organic nutrients and carbon (C) from their catchments. How bacterioplankton respond to these inputs is not well understood, in part because we base our understanding and predictions on total pools, yet we know little about the stoichiometry of bioavailable elements within organic matter. We designed bioassays with the purpose of exhausting the pools of readily bioavailable dissolved organic carbon (BDOC), bioavailable dissolved nitrogen (BDN), and bioavailable dissolved phosphorus (BDP) as fast as possible. Applying the method in four boreal lakes at base-flow conditions yielded concentrations of bioavailable resources in the range 105–693 µg C L−1 for BDOC (2 % of initial total DOC), 24–288 µg N L−1 for BDN (31 % of initial total dissolved nitrogen), and 0.2–17 µg P L−1 for BDP (49 % of initial total dissolved phosphorus). Thus, relative bioavailability increased from carbon (C) to nitrogen (N) to phosphorus (P). We show that the main fraction of bioavailable nutrients is organic, representing 80 % of BDN and 61 % of BDP. In addition, we demonstrate that total C : N and C : P ratios are as much as 13-fold higher than C : N and C : P ratios for bioavailable resource fractions. Further, by applying additional bioavailability measurements to seven widely distributed rivers, we provide support for a general pattern of relatively high bioavailability of P and N in relation to C. Altogether, our findings underscore the poor availability of C for support of bacterial metabolism in boreal C-rich freshwaters, and suggest that these ecosystems are very sensitive to increased input of bioavailable DOC.},
  author       = {Soares, Ana and Bergström, Ann-Kristin and Sponseller, Ryan A. and Marchlewska Moberg, Joanna and Giesler, Reiner and Kritzberg, Emma and Jansson, Mats and Berggren, Martin},
  issn         = {1726-4189},
  language     = {eng},
  month        = {03},
  number       = {6},
  pages        = {1527--1539},
  publisher    = {Copernicus Publications},
  series       = {Biogeosciences},
  title        = {New insights on resource stoichiometry: assessing availability of carbon, nitrogen, and phosphorus to bacterioplankton},
  url          = {http://dx.doi.org/10.5194/bg-14-1527-2017},
  volume       = {14},
  year         = {2017},
}