Light history-dependent respiration explains the hysteresis in the daily ecosystem metabolism of seagrass
Adams, Matthew P., Ferguson, Angus J. P., Maxwell, Paul S., Lawson, Brodie A. J., Samper-Villarreal, Jimena, & O'Brien, Katherine R. (2015) Light history-dependent respiration explains the hysteresis in the daily ecosystem metabolism of seagrass. Hydrobiologia: the international journal of aquatic sciences.
Oxygen flux between aquatic ecosystems and the water column is a measure of ecosystem metabolism. However, the oxygen flux varies during the day in a “hysteretic” pattern: there is higher net oxygen production at a given irradiance in the morning than in the afternoon. In this study, we investigated the mechanism responsible for the hysteresis in oxygen flux by measuring the daily pattern of oxygen flux, light, and temperature in a seagrass ecosystem (Zostera muelleri in Swansea Shoals, Australia) at three depths. We hypothesised that the oxygen flux pattern could be due to diel variations in either gross primary production or respiration in response to light history or temperature. Hysteresis in oxygen flux was clearly observed at all three depths. We compared this data to mathematical models, and found that the modification of ecosystem respiration by light history is the best explanation for the hysteresis in oxygen flux. Light history-dependent respiration might be due to diel variations in seagrass respiration or the dependence of bacterial production on dissolved organic carbon exudates. Our results indicate that the daily variation in respiration rate may be as important as the daily changes of photosynthetic characteristics in determining the metabolic status of aquatic ecosystems.
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|Item Type:||Journal Article|
|Keywords:||seagrass, net ecosystem metabolism, oxygen, production, respiration, submerged aquatic vegetation|
|Subjects:||Australian and New Zealand Standard Research Classification > MATHEMATICAL SCIENCES (010000) > APPLIED MATHEMATICS (010200)
Australian and New Zealand Standard Research Classification > ENVIRONMENTAL SCIENCES (050000) > ECOLOGICAL APPLICATIONS (050100)
|Divisions:||Current > Schools > School of Mathematical Sciences
Current > QUT Faculties and Divisions > Science & Engineering Faculty
|Copyright Owner:||Copyright 2015 Springer International Publishing Switzerland|
|Copyright Statement:||The final publication is available at Springer via http://dx.doi.org/10.1007/s10750-015-2444-5|
|Deposited On:||01 Sep 2015 00:28|
|Last Modified:||01 Sep 2015 23:56|
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