5th UF Water Institute Symposium Abstract

Submitter's Name Lily Kirk
Session Name Poster Session - Springs & Rivers
Poster Number 41
Author(s) Lily Kirk,  School of Natural Resources and Environment (Presenting Author)
  Matthew Cohen,  School of Forest Resources and Conservation
  Can simultaneous O2 and CO2 measurement illuminate respiration dynamics in rivers?
  The respiratory quotient (RQ = moles CO2 produced/moles O2 consumed during aerobic respiration) is used to convert ecosystem metabolism rates measured in oxygen to carbon fluxes. There are few direct measurements of RQ in aquatic systems, and it is often assumed to be 1. Actual RQ is a function of organic matter composition, and we propose to use it to tease apart the differential respiration of organic carbon in sediments. To scale up from controlled laboratory experiments to in situ open water measurements in rivers, we first need to determine the effect of reaeration on RQ. Deviations in open water CO2:O2 molar ratios from the RQ will allow us to partition between aerobic and anaerobic respiration. If anaerobic respiration is high, there is the possibility that we have been underestimating ecosystem respiration – and hence overestimating net ecosystem production – by only calculating ecosystem metabolism using oxygen concentrations.