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The tight coupling of photosynthesis and respiration during base flow in the Australian wet-dry tropics

Townsend, Simon, Webster, I. and Schult, J. (2010). The tight coupling of photosynthesis and respiration during base flow in the Australian wet-dry tropics. In: Joint American Society for Limnology and North American Benthological Society Conference, Santa Fe, New Mexico, United States, 6-11 June 2010.

Document type: Conference Paper
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IRMA ID 81704288xPUB413
Author Townsend, Simon
Webster, I.
Schult, J.
Title The tight coupling of photosynthesis and respiration during base flow in the Australian wet-dry tropics
Conference Name Joint American Society for Limnology and North American Benthological Society Conference
Conference Location Santa Fe, New Mexico, United States
Conference Dates 6-11 June 2010
Conference Publication Title Aquatic sciences: global changes from the center to the edge: Abstract book 2010 summer meeting
Publication Year 2010
Start Page 234
End Page 234
Total Pages 1
HERDC Category E3 - Conference Publication - Extract of paper (internal)
Abstract The rates of photosynthesis (P) and respiration (R) were calculated at 4 high order river sites during the dry season in tropical Australia when discharge is supplied by groundwater. The rivers were shallow, clear, and had low concentrations of nutrients. Increased irradiance at the riverbed, warmer water temperatures, and an increase in primary producer biomass over the dry season contributed to an approximate doubling of P. We surmise that most photosynthesis resulted in the production of dissolved organic carbon, rather than the growth of primary producer biomass which was nutrient limited.
Respiration exceeded photosynthesis (P/R ~0.5), and increased approximately linearly with P (r2 =0.79–1.00). Bacterial metabolism of photosynthetically produced dissolved organic carbon (PDOC) could partially explain the tight coupling of respiration and photosynthesis, though cannot account for the river’s overall net heterotrophy. The co-metabolism of recalcitrant dissolved organic carbon, such as humic acids, by bacteria, which is made possible by the presence of readily degraded PDOC, provides an explanation for the river’s heterotrophy and the tight coupling between P and R.
 
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Created: Fri, 17 Jan 2014, 00:11:08 CST