Toxicity of reduced nitrogen in eelgrass (Zostera marina) is highly dependent on shoot density and pH

Tj. van Heide, A.J.P. Smolders, B. Rijkens, E.H. van Nes, M.M. van Katwijk, J.G.M. Roelofs

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

In sheltered, eutrophicated estuaries, reduced nitrogen (NH x ), and pH levels in the water layer can be greatly enhanced. In laboratory experiments, we studied the interactive effects of NH x , pH, and shoot density on the physiology and survival of eelgrass (Zostera marina). We tested long-term tolerance to NH x at pH 8 in a 5-week experiment. Short-term tolerance was tested for two shoot densities at both pH 8 and 9 in a 5-day experiment. At pH 8, eelgrass accumulated nitrogen as free amino acids when exposed to high loads of NH x , but showed no signs of necrosis. Low shoot density treatments became necrotic within days when exposed to NH x at pH 9. Increased NH3 intrusion and carbon limitation seemed to be the cause of this, as intracellular NH x could no longer be assimilated. Remarkably, experiments with high shoot densities at pH 9 showed hardly any necrosis, as the plants seemed to be able to alleviate the toxic effects of high NH x loads through joint NH x uptake. Our results suggest that NH x toxicity can be important in worldwide observed seagrass mass mortalities. We argue that the mitigating effect of high seagrass biomass on NH x toxicity is a positive feedback mechanism, potentially leading to alternative stable states in field conditions.
Original languageEnglish
Pages (from-to)411-419
JournalOecologia
Volume158
Issue number3
DOIs
Publication statusPublished - 2008

Fingerprint

Zostera marina
marina
shoot
toxicity
shoots
nitrogen
seagrass
tolerance
mass mortality
experiment
feedback mechanism
necrosis
physiology
amino acid
estuary
carbon
biomass
free amino acids
estuaries
uptake mechanisms

Keywords

  • free amino-acids
  • water-column nitrate
  • false discovery rate
  • ammonium toxicity
  • submersed macrophyte
  • seagrass ecosystems
  • nutritional-status
  • sediment sulfide
  • nh4+ toxicity
  • pine needles

Cite this

van Heide, T., Smolders, A. J. P., Rijkens, B., van Nes, E. H., van Katwijk, M. M., & Roelofs, J. G. M. (2008). Toxicity of reduced nitrogen in eelgrass (Zostera marina) is highly dependent on shoot density and pH. Oecologia, 158(3), 411-419. https://doi.org/10.1007/s00442-008-1155-2
van Heide, Tj. ; Smolders, A.J.P. ; Rijkens, B. ; van Nes, E.H. ; van Katwijk, M.M. ; Roelofs, J.G.M. / Toxicity of reduced nitrogen in eelgrass (Zostera marina) is highly dependent on shoot density and pH. In: Oecologia. 2008 ; Vol. 158, No. 3. pp. 411-419.
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abstract = "In sheltered, eutrophicated estuaries, reduced nitrogen (NH x ), and pH levels in the water layer can be greatly enhanced. In laboratory experiments, we studied the interactive effects of NH x , pH, and shoot density on the physiology and survival of eelgrass (Zostera marina). We tested long-term tolerance to NH x at pH 8 in a 5-week experiment. Short-term tolerance was tested for two shoot densities at both pH 8 and 9 in a 5-day experiment. At pH 8, eelgrass accumulated nitrogen as free amino acids when exposed to high loads of NH x , but showed no signs of necrosis. Low shoot density treatments became necrotic within days when exposed to NH x at pH 9. Increased NH3 intrusion and carbon limitation seemed to be the cause of this, as intracellular NH x could no longer be assimilated. Remarkably, experiments with high shoot densities at pH 9 showed hardly any necrosis, as the plants seemed to be able to alleviate the toxic effects of high NH x loads through joint NH x uptake. Our results suggest that NH x toxicity can be important in worldwide observed seagrass mass mortalities. We argue that the mitigating effect of high seagrass biomass on NH x toxicity is a positive feedback mechanism, potentially leading to alternative stable states in field conditions.",
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van Heide, T, Smolders, AJP, Rijkens, B, van Nes, EH, van Katwijk, MM & Roelofs, JGM 2008, 'Toxicity of reduced nitrogen in eelgrass (Zostera marina) is highly dependent on shoot density and pH' Oecologia, vol. 158, no. 3, pp. 411-419. https://doi.org/10.1007/s00442-008-1155-2

Toxicity of reduced nitrogen in eelgrass (Zostera marina) is highly dependent on shoot density and pH. / van Heide, Tj.; Smolders, A.J.P.; Rijkens, B.; van Nes, E.H.; van Katwijk, M.M.; Roelofs, J.G.M.

In: Oecologia, Vol. 158, No. 3, 2008, p. 411-419.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Toxicity of reduced nitrogen in eelgrass (Zostera marina) is highly dependent on shoot density and pH

AU - van Heide, Tj.

AU - Smolders, A.J.P.

AU - Rijkens, B.

AU - van Nes, E.H.

AU - van Katwijk, M.M.

AU - Roelofs, J.G.M.

PY - 2008

Y1 - 2008

N2 - In sheltered, eutrophicated estuaries, reduced nitrogen (NH x ), and pH levels in the water layer can be greatly enhanced. In laboratory experiments, we studied the interactive effects of NH x , pH, and shoot density on the physiology and survival of eelgrass (Zostera marina). We tested long-term tolerance to NH x at pH 8 in a 5-week experiment. Short-term tolerance was tested for two shoot densities at both pH 8 and 9 in a 5-day experiment. At pH 8, eelgrass accumulated nitrogen as free amino acids when exposed to high loads of NH x , but showed no signs of necrosis. Low shoot density treatments became necrotic within days when exposed to NH x at pH 9. Increased NH3 intrusion and carbon limitation seemed to be the cause of this, as intracellular NH x could no longer be assimilated. Remarkably, experiments with high shoot densities at pH 9 showed hardly any necrosis, as the plants seemed to be able to alleviate the toxic effects of high NH x loads through joint NH x uptake. Our results suggest that NH x toxicity can be important in worldwide observed seagrass mass mortalities. We argue that the mitigating effect of high seagrass biomass on NH x toxicity is a positive feedback mechanism, potentially leading to alternative stable states in field conditions.

AB - In sheltered, eutrophicated estuaries, reduced nitrogen (NH x ), and pH levels in the water layer can be greatly enhanced. In laboratory experiments, we studied the interactive effects of NH x , pH, and shoot density on the physiology and survival of eelgrass (Zostera marina). We tested long-term tolerance to NH x at pH 8 in a 5-week experiment. Short-term tolerance was tested for two shoot densities at both pH 8 and 9 in a 5-day experiment. At pH 8, eelgrass accumulated nitrogen as free amino acids when exposed to high loads of NH x , but showed no signs of necrosis. Low shoot density treatments became necrotic within days when exposed to NH x at pH 9. Increased NH3 intrusion and carbon limitation seemed to be the cause of this, as intracellular NH x could no longer be assimilated. Remarkably, experiments with high shoot densities at pH 9 showed hardly any necrosis, as the plants seemed to be able to alleviate the toxic effects of high NH x loads through joint NH x uptake. Our results suggest that NH x toxicity can be important in worldwide observed seagrass mass mortalities. We argue that the mitigating effect of high seagrass biomass on NH x toxicity is a positive feedback mechanism, potentially leading to alternative stable states in field conditions.

KW - free amino-acids

KW - water-column nitrate

KW - false discovery rate

KW - ammonium toxicity

KW - submersed macrophyte

KW - seagrass ecosystems

KW - nutritional-status

KW - sediment sulfide

KW - nh4+ toxicity

KW - pine needles

U2 - 10.1007/s00442-008-1155-2

DO - 10.1007/s00442-008-1155-2

M3 - Article

VL - 158

SP - 411

EP - 419

JO - Oecologia

JF - Oecologia

SN - 0029-8549

IS - 3

ER -