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Nighttime and daytime respiration in a headwater stream
Author(s) -
GonzálezPinzón Ricardo,
Peipoch Marc,
Haggerty Roy,
Martí Eugènia,
Fleckenstein Jan H.
Publication year - 2016
Publication title -
ecohydrology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.982
H-Index - 54
eISSN - 1936-0592
pISSN - 1936-0584
DOI - 10.1002/eco.1615
Subject(s) - daytime , photosynthetically active radiation , diel vertical migration , environmental science , respiration , atmospheric sciences , riparian zone , canopy , hydrology (agriculture) , ecosystem respiration , ecosystem , photosynthesis , eddy covariance , ecology , chemistry , geology , biology , botany , biochemistry , geotechnical engineering , habitat
We investigated changes in respiration across nighttime and daytime in a headwater stream. For this, we conducted consecutive nighttime and daytime experiments injecting the bioreactive tracer resazurin in two reaches with different riparian canopy densities (different levels of photosynthetically active radiation) to compare respiration rate coefficients. We found that even though stream water temperatures measured above the streambed at day and night (half‐day timescale) were different within each reach and across reaches (95% confidence level), apparent respiration rate coefficients were not different across nighttime and daytime conditions (95% confidence level). A likely explanation for this is that the bulk of stream respiration takes place in the hyporheic zone, where diel fluctuations of stream temperature and photosynthetically active radiation are considerably attenuated and where temperature is not measured in routine investigations of stream metabolism. Our results suggest that community respiration in headwater streams may not need to be ‘corrected’ for temperature between daytime and nighttime, even though instantaneous changes in respiration are expected to occur from a pure biological perspective. Copyright © 2015 John Wiley & Sons, Ltd.