Dandelion Stresses:CO2, Walkways, and

Seasonal Effects

Erin Male, William Pickles

UC Santa Cruz

September 16th, 2009

E.Male, UCSC, Sept. 2009

July 16th, 2009 (Day 1)

CO2 Stress: Dandelions over

(-1.5, 0) Hotspot

July 21st, 2009 (Day 7)

July 28th, 2009 (Day 13)

Dandelion leafs Dandelion leafs completely dead completely dead

after two weeks of after two weeks of COCO2 2 exposureexposure

E.Male, UCSC, Sept. 2009

Plant Stress in Walkways

Dandelions in a path perpendicular to injection well @ -2.2 (between hotspots) on July 30th, 2009 (Day 15)

Dandelions located west of path on July 30th, 2009

PATHPATH

•Walkway to collect plant isotope Walkway to collect plant isotope samplessamples

•Timing of the onset of stress in Timing of the onset of stress in paths (~2 weeks) inconsistent with paths (~2 weeks) inconsistent with stress from COstress from CO2 2 (~4 days)(~4 days)

•Stress in paths likely caused from Stress in paths likely caused from foot traffic and increased exposure foot traffic and increased exposure to the elements to the elements

E.Male, UCSC, Sept. 2009

Seasonal Stress

August 13th, 2009: Dandelions across the field area have changed color, indicating that they were reacting to some type of stress, most likely seasonal stresses. This larger-scale change started after ~15 days into the experiment (around the beginning of August). During the 2008 experiment, the dandelions also had a similar reaction. In both years, the change in color was mostly limited to dandelion plants within the plant study area, which were not mowed.