The effects of grazing by the snail, Lymnaea elodes, on benthic N2 fixation and primary production in oligotrophic, arctic lakes
This study assessed whether grazing by the snail, Lymnaea elodes , limits benthic dinitrogen (N 2 ) fixation and primary production in nitrogen (N)‐limited oligotrophic lakes near Toolik Field Station on the North Slope of Alaska. We also tested whether snail excretion increased N and the ratio of N...
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crwiley:10.4319/lo.2007.52.6.2398 2024-04-28T08:12:25+00:00 The effects of grazing by the snail, Lymnaea elodes, on benthic N2 fixation and primary production in oligotrophic, arctic lakes Gettel, Gretchen M. Giblin, Anne E. Howarth, Robert W. 2007 http://dx.doi.org/10.4319/lo.2007.52.6.2398 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.4319%2Flo.2007.52.6.2398 https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.2007.52.6.2398 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Limnology and Oceanography volume 52, issue 6, page 2398-2409 ISSN 0024-3590 1939-5590 Aquatic Science Oceanography journal-article 2007 crwiley https://doi.org/10.4319/lo.2007.52.6.2398 2024-04-02T08:40:50Z This study assessed whether grazing by the snail, Lymnaea elodes , limits benthic dinitrogen (N 2 ) fixation and primary production in nitrogen (N)‐limited oligotrophic lakes near Toolik Field Station on the North Slope of Alaska. We also tested whether snail excretion increased N and the ratio of N and phosphorus (P) supply ratio to benthic algae, which could indirectly affect production and the N 2 fixation rate. We performed in situ , randomized block experiments in two lakes in 3 years in which snail density was manipulated and compared to open cage controls. Snails significantly decreased areal rates of N 2 fixation in both lakes in all years (p < 0.05), but did not appear to cause a reduction in cyanobacterial abundance or filament size (p > 0.05). Snails did not significantly affect measures of benthic production, including gross primary production, respiration, net ecosystem production, and chlorophyll biomass (p > 0.05). Snail‐induced declines in N 2 fixation probably did not result from snail excretion. The molar N: P excretion ratio of ammonium (NH 4 + ) and phosphate (PO 4 + ) was very low (4.8), indicating that snails likely exacerbated N limitation, a response that would tend to favor enhanced rather than reduced N 2 fixation. Furthermore, the excretion rate of N‐NH 4 + was several orders of magnitude lower than the N 2 fixation rate (0.002‐0.02 mg N m −2 day −1 vs. 0.1‐0.4 mg N m −2 day −1 , respectively) and met almost none (<<1%) of the N demand by primary producers. Although the mechanism by which Lymnaea elodes caused a decline in N 2 fixation is unknown, the effect was small, and accounted for a reduction of N inputs of only 0.12 mg N m −2 summer −1 or by 0.85‐1.8% at ambient snail densities. Because N 2 fixation is a new N input able to support new production, this effect may be important across long time scales or where densities of L. elodes are higher. Article in Journal/Newspaper Arctic north slope Alaska Wiley Online Library Limnology and Oceanography 52 6 2398 2409 |
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English |
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Aquatic Science Oceanography |
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Aquatic Science Oceanography Gettel, Gretchen M. Giblin, Anne E. Howarth, Robert W. The effects of grazing by the snail, Lymnaea elodes, on benthic N2 fixation and primary production in oligotrophic, arctic lakes |
topic_facet |
Aquatic Science Oceanography |
description |
This study assessed whether grazing by the snail, Lymnaea elodes , limits benthic dinitrogen (N 2 ) fixation and primary production in nitrogen (N)‐limited oligotrophic lakes near Toolik Field Station on the North Slope of Alaska. We also tested whether snail excretion increased N and the ratio of N and phosphorus (P) supply ratio to benthic algae, which could indirectly affect production and the N 2 fixation rate. We performed in situ , randomized block experiments in two lakes in 3 years in which snail density was manipulated and compared to open cage controls. Snails significantly decreased areal rates of N 2 fixation in both lakes in all years (p < 0.05), but did not appear to cause a reduction in cyanobacterial abundance or filament size (p > 0.05). Snails did not significantly affect measures of benthic production, including gross primary production, respiration, net ecosystem production, and chlorophyll biomass (p > 0.05). Snail‐induced declines in N 2 fixation probably did not result from snail excretion. The molar N: P excretion ratio of ammonium (NH 4 + ) and phosphate (PO 4 + ) was very low (4.8), indicating that snails likely exacerbated N limitation, a response that would tend to favor enhanced rather than reduced N 2 fixation. Furthermore, the excretion rate of N‐NH 4 + was several orders of magnitude lower than the N 2 fixation rate (0.002‐0.02 mg N m −2 day −1 vs. 0.1‐0.4 mg N m −2 day −1 , respectively) and met almost none (<<1%) of the N demand by primary producers. Although the mechanism by which Lymnaea elodes caused a decline in N 2 fixation is unknown, the effect was small, and accounted for a reduction of N inputs of only 0.12 mg N m −2 summer −1 or by 0.85‐1.8% at ambient snail densities. Because N 2 fixation is a new N input able to support new production, this effect may be important across long time scales or where densities of L. elodes are higher. |
format |
Article in Journal/Newspaper |
author |
Gettel, Gretchen M. Giblin, Anne E. Howarth, Robert W. |
author_facet |
Gettel, Gretchen M. Giblin, Anne E. Howarth, Robert W. |
author_sort |
Gettel, Gretchen M. |
title |
The effects of grazing by the snail, Lymnaea elodes, on benthic N2 fixation and primary production in oligotrophic, arctic lakes |
title_short |
The effects of grazing by the snail, Lymnaea elodes, on benthic N2 fixation and primary production in oligotrophic, arctic lakes |
title_full |
The effects of grazing by the snail, Lymnaea elodes, on benthic N2 fixation and primary production in oligotrophic, arctic lakes |
title_fullStr |
The effects of grazing by the snail, Lymnaea elodes, on benthic N2 fixation and primary production in oligotrophic, arctic lakes |
title_full_unstemmed |
The effects of grazing by the snail, Lymnaea elodes, on benthic N2 fixation and primary production in oligotrophic, arctic lakes |
title_sort |
effects of grazing by the snail, lymnaea elodes, on benthic n2 fixation and primary production in oligotrophic, arctic lakes |
publisher |
Wiley |
publishDate |
2007 |
url |
http://dx.doi.org/10.4319/lo.2007.52.6.2398 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.4319%2Flo.2007.52.6.2398 https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.2007.52.6.2398 |
genre |
Arctic north slope Alaska |
genre_facet |
Arctic north slope Alaska |
op_source |
Limnology and Oceanography volume 52, issue 6, page 2398-2409 ISSN 0024-3590 1939-5590 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.4319/lo.2007.52.6.2398 |
container_title |
Limnology and Oceanography |
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52 |
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6 |
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2398 |
op_container_end_page |
2409 |
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1797579289785270272 |