Ocean warming, but not acidification, accelerates seagrass decomposition under near-future climate scenarios

Brendan P. Kelaher, Melinda A. Coleman, Melanie J. Bishop

Research output: Contribution to journalArticleResearchpeer-review

Abstract

The majority of marine macrophyte production is not consumed by herbivores but instead is channeled into detrital pathways where it supports biodiversity and drives coastal productivity, nutrient cycling and blue carbon sequestration. While it is clear that detrital pathways will be affected by ocean climate change, the relative importance of changing temperature or pH, or their interactions, has not been assessed. We used outdoor mesocosm experiments to assess the relative importance of ocean warming, acidification and latitude of litter origin on the decomposition and biomechanical properties of seagrass Zostera muelleri. Seagrass, collected from 2 sites at each of 2 latitudes (29º and 35º S), was subjected to an orthogonal combination of current and predicted future ocean warming (+3ºC) and acidification (-0.3 pH unit). Elevated temperatures resulted in a 15% greater loss of seagrass detrital mass. Mass loss of seagrass detritus was also greater in seagrass from higher than from lower latitudes. The stiffness (Young's modulus) of decomposing seagrass was greater at 22º C than at 25º C. Elevated sea temperatures also weakened decomposing seagrass, but the magnitude of these effects was greater for Z. muelleri originating from higher than from lower latitudes. Overall, ocean warming is likely to have a much larger influence on seagrass decomposition than ocean acidification. As climate changes, however, if seagrass from higher latitudes takes on similar characteristics to seagrass currently growing at lower latitudes, there may be a negative feedback against the impacts of ocean warming on decomposition, moderating changes in associated primary and secondary productivity that supports coastal fisheries and ecosystem processes.

LanguageEnglish
Pages103-110
Number of pages8
JournalMarine Ecology Progress Series
Volume605
DOIs
Publication statusPublished - 26 Oct 2018

Bibliographical note

Copyright Inter-Research 2018. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

Keywords

  • ocean climate change
  • ocean warming
  • acidification
  • seagrass
  • decomposition
  • eelgrass
  • Zostera

Cite this

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title = "Ocean warming, but not acidification, accelerates seagrass decomposition under near-future climate scenarios",
abstract = "The majority of marine macrophyte production is not consumed by herbivores but instead is channeled into detrital pathways where it supports biodiversity and drives coastal productivity, nutrient cycling and blue carbon sequestration. While it is clear that detrital pathways will be affected by ocean climate change, the relative importance of changing temperature or pH, or their interactions, has not been assessed. We used outdoor mesocosm experiments to assess the relative importance of ocean warming, acidification and latitude of litter origin on the decomposition and biomechanical properties of seagrass Zostera muelleri. Seagrass, collected from 2 sites at each of 2 latitudes (29º and 35º S), was subjected to an orthogonal combination of current and predicted future ocean warming (+3ºC) and acidification (-0.3 pH unit). Elevated temperatures resulted in a 15{\%} greater loss of seagrass detrital mass. Mass loss of seagrass detritus was also greater in seagrass from higher than from lower latitudes. The stiffness (Young's modulus) of decomposing seagrass was greater at 22º C than at 25º C. Elevated sea temperatures also weakened decomposing seagrass, but the magnitude of these effects was greater for Z. muelleri originating from higher than from lower latitudes. Overall, ocean warming is likely to have a much larger influence on seagrass decomposition than ocean acidification. As climate changes, however, if seagrass from higher latitudes takes on similar characteristics to seagrass currently growing at lower latitudes, there may be a negative feedback against the impacts of ocean warming on decomposition, moderating changes in associated primary and secondary productivity that supports coastal fisheries and ecosystem processes.",
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Ocean warming, but not acidification, accelerates seagrass decomposition under near-future climate scenarios. / Kelaher, Brendan P.; Coleman, Melinda A.; Bishop, Melanie J.

In: Marine Ecology Progress Series, Vol. 605, 26.10.2018, p. 103-110.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Ocean warming, but not acidification, accelerates seagrass decomposition under near-future climate scenarios

AU - Kelaher,Brendan P.

AU - Coleman,Melinda A.

AU - Bishop,Melanie J.

N1 - Copyright Inter-Research 2018. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

PY - 2018/10/26

Y1 - 2018/10/26

N2 - The majority of marine macrophyte production is not consumed by herbivores but instead is channeled into detrital pathways where it supports biodiversity and drives coastal productivity, nutrient cycling and blue carbon sequestration. While it is clear that detrital pathways will be affected by ocean climate change, the relative importance of changing temperature or pH, or their interactions, has not been assessed. We used outdoor mesocosm experiments to assess the relative importance of ocean warming, acidification and latitude of litter origin on the decomposition and biomechanical properties of seagrass Zostera muelleri. Seagrass, collected from 2 sites at each of 2 latitudes (29º and 35º S), was subjected to an orthogonal combination of current and predicted future ocean warming (+3ºC) and acidification (-0.3 pH unit). Elevated temperatures resulted in a 15% greater loss of seagrass detrital mass. Mass loss of seagrass detritus was also greater in seagrass from higher than from lower latitudes. The stiffness (Young's modulus) of decomposing seagrass was greater at 22º C than at 25º C. Elevated sea temperatures also weakened decomposing seagrass, but the magnitude of these effects was greater for Z. muelleri originating from higher than from lower latitudes. Overall, ocean warming is likely to have a much larger influence on seagrass decomposition than ocean acidification. As climate changes, however, if seagrass from higher latitudes takes on similar characteristics to seagrass currently growing at lower latitudes, there may be a negative feedback against the impacts of ocean warming on decomposition, moderating changes in associated primary and secondary productivity that supports coastal fisheries and ecosystem processes.

AB - The majority of marine macrophyte production is not consumed by herbivores but instead is channeled into detrital pathways where it supports biodiversity and drives coastal productivity, nutrient cycling and blue carbon sequestration. While it is clear that detrital pathways will be affected by ocean climate change, the relative importance of changing temperature or pH, or their interactions, has not been assessed. We used outdoor mesocosm experiments to assess the relative importance of ocean warming, acidification and latitude of litter origin on the decomposition and biomechanical properties of seagrass Zostera muelleri. Seagrass, collected from 2 sites at each of 2 latitudes (29º and 35º S), was subjected to an orthogonal combination of current and predicted future ocean warming (+3ºC) and acidification (-0.3 pH unit). Elevated temperatures resulted in a 15% greater loss of seagrass detrital mass. Mass loss of seagrass detritus was also greater in seagrass from higher than from lower latitudes. The stiffness (Young's modulus) of decomposing seagrass was greater at 22º C than at 25º C. Elevated sea temperatures also weakened decomposing seagrass, but the magnitude of these effects was greater for Z. muelleri originating from higher than from lower latitudes. Overall, ocean warming is likely to have a much larger influence on seagrass decomposition than ocean acidification. As climate changes, however, if seagrass from higher latitudes takes on similar characteristics to seagrass currently growing at lower latitudes, there may be a negative feedback against the impacts of ocean warming on decomposition, moderating changes in associated primary and secondary productivity that supports coastal fisheries and ecosystem processes.

KW - ocean climate change

KW - ocean warming

KW - acidification

KW - seagrass

KW - decomposition

KW - eelgrass

KW - Zostera

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M3 - Article

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EP - 110

JO - Marine Ecology Progress Series

T2 - Marine Ecology Progress Series

JF - Marine Ecology Progress Series

SN - 0171-8630

ER -