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Volume 2 Number 18:  15 September 1999

Editorial
Carbon Dioxide - The Straw Man of the Alternative Energy Crowd: The wind turbines on the cover of Science intrigued us.  Looking inside the 30 July 1999 issue, we read they were put there to highlight a special section of the magazine that focused on alternative approaches to fossil fuel combustion as a means of energy generation, which process, the caption warned, "may lead to restricted fossil fuel use" because of concerns about global warming...

Journal Reviews
1997-98 El Niņo Impacts for the United States: The economic impacts of the 1997-98 El Niņo event were analyzed for the United States and found to be "surprisingly positive," as were its effects on human mortality.

Vegetative Response to Rapid Climate Change in Southern Europe: A study of the vegetative and climatic history of southern Europe over the past 102,000 years reveals that the vegetation of this region was enhanced during periods of warmer temperatures.

Emerging Marine Diseases: The authors reviewed the literature dealing with the emergence of marine diseases, suggesting that marine disease is more prevalent now than in the past, due to the spread of pathogens from human and other terrestrial sources.

Coral Adaptation to Solar-Induced Bleaching?: Measurements of coral proteins before and after a bleaching event suggest that corals may be able to reduce their susceptibility to subsequent bleaching by increasing their production of photoprotective proteins.

Cosmic Rays and 20th Century Climate Change: The authors study the variable cosmic ray transmission through portions of Earth's atmosphere, concluding that it could significantly alter cloudiness patterns which could in turn alter mean surface air temperature.

Seasonal Photosynthetic Response of Pine to Elevated CO2: In mature loblolly pine trees, atmospheric CO2 enrichment influenced the light-dependent reactions of photosynthesis in a season-dependent manner; with greater utilization of absorbed light energy occurring in the warmer, rather than cooler, months of the year.  However, even in the cooler months, when elevated CO2 negatively impacted light utilization, rates of net photosynthesis were still greater in CO2-enriched trees.

Effects of Elevated CO2 on Mycorrhizal Colonization of Plantago lanceolata and Trifolium repens: Two plant species inoculated with an arbuscular mycorrhizal fungus, and grown for 75 days in open-top chambers enriched to an atmospheric CO2 concentration of 650 ppm, displayed greater shoot and root dry weights than did plants grown at 400 ppm CO2.  Although elevated CO2 increased the total and percentage root length colonized by the mycorrhizal fungus in both plant species, these observations resulted more from the CO2-induced increase in plant size and less from a direct effect of atmospheric CO2 enrichment on the fungus.  Additionally, both plants experienced some degree of photosynthetic acclimation, as indicated by an optimization of P utilization late in the experiment.

Effects of Elevated CO2 and Light Intensity on Fungal-Plant Relationships in Potato: Potato plantlets grown at an atmospheric CO2 concentration of 10,000 ppm for one month displayed greater root colonization by mycorrhizal fungi than plantlets grown at ambient CO2, regardless of light intensity.  In addition, elevated CO2 and fungal inoculation stimulated dry matter production when combined with high, but not low, light intensity.  Fungal inoculation also reduced the degree of photosynthetic down regulation observed in CO2-enriched plants by effectively increasing their sink strength.

Stomatal Responses of Wild Radish to Elevated CO2: Although the stomatal indices and reproductive characteristics of twelve wild radish genotypes were inherently different, atmospheric CO2 enrichment did not significantly nor differentially affect these characteristics, suggesting that elevated CO2 will maintain the genetic diversity that exists within this species.

Stomatal Responses of Temperate Woodland Plants to Elevated CO2: After measuring the stomatal densities of 60 temperate woodland trees, shrubs, and herbs and comparing them with similar data collected in 1927, it was determined that the rising CO2 content of the air over the past 70 years significantly reduced stomatal densities, regardless of plant form.  Thus, reductions in stomatal density were likely accompanied by parallel reductions in stomatal conductance and transpirational water loss in those species.