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Volume 2 Number 4:  15 February 1999

Editorial
More CO2 Helps Plants Grow Better: Fourth-Grader and Her Father Prove It to Themselves And to Her Classmates: A couple of months ago, Christie Shumway needed to do a science project for her fourth-grade class at Hudson Elementary School in Tempe, Arizona.  Her father is a personal friend of ours, and he asked us if we had any ideas.  We told him to check out the Global Change Laboratory in the Experiments section of our web site; and now his daughter's smiling face introduces this issue's editorial...

Journal Reviews
Airplanes and Climate Change: A study of cloud data between 1982-1991 suggests that cirrus cloud cover has increased globally by 1-3% as a result of increased air traffic.

Effect of Sea Level on Climate: Evidence is presented that suggests that a large portion of the current rate of sea level rise may be due to geologic sea-floor spreading, independent of climate change due to orbital or anthropogenic causes.

Precipitation Decrease in the Western Arctic: Analysis of various climatological data in the western Arctic reveal a decrease in precipitation frequency and intensity, coupled with a slight temperature increase since the late 1940s.

Past Temperatures in China: A review of climatic conditions in China during the Holocene reveals that temperatures were 2-6C warmer than at present at a time, from 6,000 to 9,000 years ago, when atmospheric CO2 concentrations were 100 ppm lower than they are today.

Streamflow Trends in the United States: A study of streamflow trends at 395 stations in the United States shows the country to have gotten wetter in the mean, but less variable at the extremes, where floods and droughts occur, over the greater portion of the past century.

Effects of Elevated CO2 on Tropical Forest Trees: Elevated CO2 increased total nonstructural carbohydrate concentrations in leaves of four tropical tree species located in Panama.

Effects of Elevated CO2 on Tropical Trees: After six months of atmospheric CO2 enrichment, ten tropical forest tree species growing in open-top chambers situated on the edge of a tropical forest in Panama exhibited increased rates of net assimilation and increased leaf starch concentrations.

Role of Starch in Acclimation to Elevated CO2: After seven weeks of atmospheric CO2 enrichment, transformed potato plants, with severely reduced starch synthesizing capabilities, displayed decreases in photosynthetic rates, whereas untransformed normal plants exhibited photosynthetic increases.  Photosynthetic acclimation in transformed plants was not due to starch accumulation, nor to loss of rubisco activity, but rather to an inability to synthesize starch.  Thus, the accumulation of starch in plants exposed to elevated CO2, a phenomenon once thought to be detrimental to continued enhancement of photosynthesis, may actually be supportive of continued high growth rates.

Sink Size Affects Elevated CO2 Growth Response in Brassica: Young Brassica species all responded positively to atmospheric CO2 enrichment by increasing their dry weights.  However, at final harvest following maturation, only those species possessing well-developed carbon sinks exhibited significantly greater dry weights than those observed in control plants grown at ambient CO2.

Effects of Plant Productivity on Herbivore Diversity: Nitrogen fertilization increased plant productivity in upland grass communities of Minnesota; and this productivity increase enhanced arthropod biodiversity by increasing the numbers of species of herbivores, parasites, and predators.