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Long‐term trends and resilience of seagrass metabolism: A decadal aquatic eddy covariance study
Author(s) -
Berger Amelie C.,
Berg Peter,
McGlathery Karen J.,
Delgard Marie Lise
Publication year - 2020
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.1002/lno.11397
Subject(s) - seagrass , eddy covariance , environmental science , trophic level , zostera marina , ecosystem , benthic zone , ecosystem respiration , primary production , ecology , zostera , oceanography , atmospheric sciences , biology , geology
Abstract Seagrass meadows are valued for their ecosystem services, including their role in mitigating anthropogenic CO 2 emissions through ‘blue carbon’ sequestration and storage. This study quantifies the dynamics of whole ecosystem metabolism on daily to interannual timescales for an eelgrass ( Zostera marina ) meadow using in situ benthic O 2 flux measurements by aquatic eddy covariance over a period of 11 yr. The measurements were part of the Virginia Coast Reserve Long‐Term Ecological Research study, and covered a relatively stable period of seagrass ecosystem metabolism 6–13 yr after restoration by seeding (2007–2014), a die‐off event likely related to persistently high temperatures during peak growing season in 2015, and a partial recovery from 2016 to 2018. This unique sequence provides an unprecedented opportunity to study seagrass resilience to temperature stress. With this extensive data set covering 115 full diel cycles, we constructed an average annual oxygen budget that indicated the meadow was in metabolic balance when averaged over the entire period, with gross primary production and respiration equal to 95 and −94 mmol O 2 m −2 d −1 , respectively. On an interannual scale, there was a shift in trophic status from balanced to net heterotrophy during the die‐off event in 2015, then to net autotrophy as the meadow recovered. The highly dynamic and variable nature of seagrass metabolism captured by our aquatic eddy covariance data emphasizes the importance of using frequent measurements throughout the year to correctly estimate trophic status of seagrass meadows.