LICHENS AS BIOMONITORS OF AIR QUALITY IN THE SOUTH COAST
Evaluation Monitoring Grant # WC-EM-07-05
AIR BASIN OF CALIFORNIA
RIDDELL,
1,2
JENNIFER ,
Pamela
2
Padgett ,
Thomas H. Nash
1
III
1.Arizona State University, School of Life Sciences, POB 874601, Tempe AZ 85287, (jennifer.riddell@asu.edu); 2. USDA FS, Pacific SW Research Station, Riverside, CA;
biomonitors of air pollution for over a
century, beginning in the industrializing
European nations in the 1850’s. Their
usefulness is tied to the fact that lichen
species are differentially responsive to
pollutants, and lichen community
composition changes readily with shifts
in air quality. Monitoring changes in
lichen communities allows for early
detection of potentially greater
ecosystem change due to air quality.
However, for this type of monitoring to
be effective, lichen responses need to
be calibrated to pollution levels.
Day 1
Day 7
25
Day 28
20
15
10
5
0
Humid HNO3
Humid Control
Dry HNO3
Dry Control
Figure 3
40
Ozone fumigations
were conducted for two
months, and O3 levels
were 0, 60 and 120
ppb. (Winter 2007-08)
-1
Gross Photosynthesis of Ramalina menziesii
in Ozone Fumigations
Day 14
Day 28
Day 42
30
Day 56
25
20
15
10
0
No O3
60 ppb
120ppb
Figures 3 and 4:
Gross photosynthesis and
chlorophyll content of R.
menziesii in O3 fumigation
chambers. Treated thalli
did not show significant
physiological decline in
response to O3
fumigations.
Day 14
Day 28
1.5
1
0.5
0
Humid HNO3
Ambient Air
Transplant
Experiments
Santa Rosa Plateau
(moderate pollution)
40
35
Gross Photosynthesis of Ramalina menziesii in
Ozone X Nitric Acid Fumigations
20
18
Day 1
Day 18
Day 36
16
14
12
10
8
6
4
2
0
HNO3
HNO3xO3
O3
Control
Figures 5 and 6:
Gross photosynthesis and
chlorophyll content of R.
menziesii in O3 x HNO3
fumigation chambers.
Ozone treatment
responses did not differ
significantly from control
fumigations, but was
significantly different from
HNO3 fumigations
(p<0.001).
3.0
Chlorophyll Content of Ramalina menziesii
Tissue Fumigated with Ozone
20
7/10/2007
7/24/2007
8/7/2007
8/21/2007
15
10
5
Palomar Mountain
(control site)
9/4/2007
9/18/2007
10/2/2007
0
High Deposition- San Dimas
Moderate Deposition - Santa Rosa Control Site - Sedgwick Reserve
Plateau
Acknowledgements:
Day 1
Day 14
Day 42
Day 56
Day 28
2.5
2.0
1.5
1.0
0.5
0.0
60 ppb
120 ppb
3.5
3
Chlorophyll Content of Ramalina menziesii Tissue
Fumigated with Ozone and Nitric Acid
Day 1
Day 18
Day 34
2.5
2
1.5
1
0.5
0
HNO3
HNO3xO3
O3
Control
Our fumigations to date have demonstrated
that Ramalina menziesii is highly sensitive
to gaseous HNO3, and far less responsive
to ozone, contrary to previous thought.
Converse Flat
(moderate pollution)
30
6/20/2007
6/26/2007
Dry control
Conclusions
Gross Photosynthesis of Transplanted Ramalina menziesii
Summer 2007
25
Dry HNO3
Figure 6
Camp Paivika
(high pollution)
Los Angeles
Humid control
Ozone Concentrations in Treatments
San Dimas
(high pollution)
µ g C O 2 g a in e d / g o v e n d rie d w e ig h t m in -1
Day 7
2
no O3
Sedgwick Reserve
(control site)
1. Padgett, PE and A Bytnerowicz, PJ Dawson. 2004. Design, evaluation and application of a continuously stirred tank reactor system for use in nitric acid air pollution
studies. Water Air and Soil Pollution, 151 (1-4): 35-51
2. Riddell. J., T.H. Nash III, P. Padgett. 2008. The effect of HNO3 gas on the lichen Ramalina menziesii. Flora 204 pp.47-54.
3.Sigal, L. L. 1979. I. Lichen communities of southern California mountains : an ecological survey relative to oxidant air pollution. II. Gross photosynthetic response of
lichens to short-term ozone fumigations. III. Preliminary studies of the gross photosynthetic response of lichens to peroxyacetyl nitrate fumigations. Thesis. Arizona State
University.
Day 1
Day 1
5
-1
O3 X HNO3
Fumigations
Lichen samples were
treated with a 2x2
factorial fumigation:
80ppb O3, 80ppb O3X
HNO3, and HNO3 for
36 days. (Winter 200809)
References:
2.5
Figure 4
Figure 5
Gas levels can be controlled in each of our ten
chambers, allowing for multiple levels of fumigations.
With an understanding of the effects of the
pollutants and independent toxicants on R.
menziesii in fumigation chambers, we investigated
the effects of ambient pollution under field
conditions. We transplanted Ramalina menziesii
(left), a sensitive species extirpated from the area
from pristine locations to moderate and high
pollution sites, monitoring them over the summer
and fall of 2007. The map (above right) of S.
California shows transplant sites.
Chlorophyll Content of Ramalina menziesii Tissue Fumigated with Nitric
Acid
Ozone Condentrateion in Treatments
We used fumigation chambers1 to conduct controlled
investigations of each pollutant independently and in
2 x 2 factorial fumigations using the pollution sensitive
lichen species Ramalina menziesii.
nitric acid (HNO3) pollutants often cooccur in urbanized arid regions, as they
are formed by the same photochemical
reactions between nitrogen oxide
(mostly from automobile emissions) and
volatile organic compounds. Research
on the effects of O3 and HNO3 has
focused on toxicity to plants and
humans, and the toxicity of O3 to both is
well established. Much less is known
about the effects of the individual
pollutants on lichen biology. This
research seeks to understand
independent and combined effects of O3
and HNO3 on lichen biology and
distribution.
µg CO2 gained / g odw min
Ozone
Fumigations
35
µg CO2 gained/ g odw min
Pollution: Ozone (O3) and gaseous
HNO3 levels ranged
from 7 to 35 μg m-3 24
hour averages for one
month. (Winter 2006-07)
30
3
mg chlorophyll per g air dry
weight
Lichens: Lichens have been used as
µ g C O 2 g ain ed / g o d w m in -1
Fumigation Experiments
Nitric Acid
Fumigations2
Gross Photosynthesis of Ramalina menziesii in HNO3
Fumigations
Figures 1 and 2:
Gross photosynthesis and
chlorophyll content of R.
menziesii in HNO3
fumigation chambers.
Treated thalli showed
significant physiological
decline in response to
HNO3 fumigations (p<
0.001 for photosynthesis
and chlorophyll). Humidity
was an important
mitigating factor.
mg Chlorophyll / g air dry tissue
Overview
35
Figure 2
m g ch lo ro ph yll / g d r y tissue
Figure 1
Pollution levels at sites were monitored
with passive filter HNO3, NH3, and O3
monitors at two week intervals over the
course of the transplant experiment.
Figure 7: Gross photosynthesis of
transplanted Ramalina menziesii
thalli, which showed a sharp
physiological decline after three
weeks at San Dimas
This research is funded by the USDA Forest Service Forest Health
Monitoring Program, and the US EPA Science to Achieve Results (STAR) Fellowship Program,
and from Arizona State University. Thanks also to the Sedgwick Reserve, the
San Dimas Experimental Forest, and the Santa Rosa Plateau Preserve.
Our transplant experiments confirmed these
results, with transplanted R. menziesii
dieing within 5 weeks of being transplanted
to high pollution sites. Other species, such
as Hypogymnia imshaugii, are far more
tolerant of nitrogen pollution, and some
species thrive in the presence of high levels
of ammonia.
We are also working with other species of
lichens to capture a better idea of
community responses. By developing a
clear understanding of lichen responses to
pollution, we hope to improve the
usefulness of lichens as indicators of air
quality and forest health.