Methane production

Current atmospheric concentrations: CH 4 : ~1.7ppm CO 2 : ~380ppm On molar basis, CH 4 is 22 X’s more powerful than CO 2 as a greenhouse gas Residence time in atmosphere: 12 years CO 2 residence time: >100yrs Short-term solution to global warming: curb methane production Methane production

Global Methane Budget J.R. Evans 2007 New Phytologist Imbalance: ~22 Tg CH 4 yr -1

Tropical forest methane budget: Soils are a sink Sources: Wetland Biomass burning Aerobic plant source Termites (e.g. Megonigal and Guenther 2008; Evans 2007; do Carmo et al, 2006; Martius et al., 1993)

What is the methane production of termite colonies? Tom Powell, Daniela Pauletto, Carlos Querino, Manuella Souza, Joost van Haren

Characteristics 500 species in Brazil; Ruminants Facilitates decomposition processes and nutrient cycling; Aerates soil, facilitates drainage of the soil and mixes nutrients.

Termites habitat Soil Arboreal

Hypothesis 1: Selective logging influences colony density.

Hypothesis 2: Methane production from arboreal termite colonies is an important constituent of the Amazon forest methane budget.

PART I: Colony biometrics

Termites colonies inventory 1. Area Control – undisturbed 2. Area logged at Area logged at 2003 Areas selected: Sampled Plots per Area 50 x 250 m (1.25 ha)

Data collected Colony Dimensions (volume) Number of colonies Location of colony in plot: X and Y coordinates (m) Termite colony status: active or inactive

Limitations of the inventory Measure termite colonies high in trees and in soil; Verify termite colony activity; Find termite colony

D ENSITY OF A RBOREAL T ERMITE C OLONIES Active Inactive Hypothesis 1: Confirmed (plot size: 1.25 ha) significant at 95% confidence boundary * * *

Part II Methane fluxes

Methods: Enclose tree colonies in the “tent” chamber. Draw 4 gas samples at time 0 minutes, 10 minutes, 20 minutes and 30 minutes. Use a gas chromatograph “GC-system” to measure the methane concentration for each period. CH 4 flux = the change in CH 4 concentration over the 30-minute period.

Chico

Raw flux data for one colony run

Hypothesis 2: methane production is a function of colony size Combine all data: 76 ± 46 mg CH 4 m -3 hr -1 Martius et al average estimate: 68.2 mg C m -3 hr -1

Hypothesis 2 not confirmed: Arboreal termite CH 4 production does not account for the methane production observed over the Amazon Basin. CH 4 flux from tree colonies: 69 g CH 4 ha -1 yr -1 Basin wide flux from tree colonies: Tg CH 4 yr -1 (area = 7 million km 2 ) Basin wide total emission: 200 Tg CH 4 yr -1 (satellite estimate, Frankenberg et al., 2008)

Conclusions: 1.Net CH 4 production from arboreal termite colonies is not a major constituent of the TNF total CH4 budget. 2.The selective-logging management strategy leads to a short term—i.e. ~ 5 years—increase in arboreal termite colony density.

Many thanks to: Scott Saleska Plinio de Camargo Paul Moorcroft Rafael Rosolem Chico NSF Amazon PIRE LBA