Heilman, M. A.. Rice University, heilman@ruf.rice.edu
Carlton, R. A.. Electric Power Research Institute, rcarlton@epri.com

 
MASS FLOW IN SUBMERSED, RHIZOMATOUS POTAMOGETON AND ITS EFFECTS ON PLANT AERATION AND LITTORAL METHANE RELEASE
 
Direct, ebullitive release of lacunar gases from the flowering spikes of a submersed, rhizomatous vascular macrophyte, Potamogeton angustifolius, was studied to determine its role in plant aeration and capacity to enhance CH4 release from vegetated sediments. Exchange of lacunar gases between clones on the same rhizome was monitored using two gas tracers (ethylene and ethane). Lacunar O2, CO2, and CH4 concentrations were also measured. For a single plant bed, rate of sediment CH4 release via plant ebullition was measured and compared to release rates via other mechanisms (diffusion from plants and sediments, and sediment ebullition). Results showed positive relationships between plant bubbling rate and transport of tracer gases. Elevated lacunar concentrations of CO2 and CH4 were also evident in ebullient clones. Release of CH4-enriched (up to 8%) bubbles from mature clones represented as much as 35% of total daytime methane emissions from P.angustifolius sediments. These data indicate that ebullition from flowering spikes provides a mechanism for sustained mass flow of lacunar gases within a submergent, rhizomatous species with implications for both plant physiology and littoral methane emission.
 
Day: Tuesday, Feb. 2
Time: 09:45 - 10:00am
Location: Eldorado Hotel
 
Code: CS56TU0945E