Harmful algal blooms threaten the water quality of many eutrophic and hypertrophic lakes and cause severe ecological and economic damage worldwide. Dense blooms often deplete the dissolved CO2 concentration and raise pH. Yet, quantitative prediction of the feedbacks between phytoplankton growth, CO2 drawdown and the inorganic carbon chemistry of aquatic ecosystems has received surprisingly litt...

The change in ancient atmospheric CO2 concentrations provides important clues for understanding the relationship between the atmospheric CO2 concentration and global temperature. However, the lack of CO2 evolution curves estimated from a single terrestrial proxy prevents the understanding of climatic and environmental impacts due to variations in data. Thus, based on the stomatal index of fossi...

One issue that seems to have been lost or avoided in the debate over the connection between atmospheric carbon dioxide (CO2) and global warming is the miniscule mass of CO2 that is being blamed for so many past, present and predicted natural disasters. The mass of atmospheric CO2 is extremely small when compared to the total mass of the Earthʼs atmosphere and even smaller when compared to the c...

We examined the effects of elevated CO2 concentration ([CO2]) on leaf demography, late-season photosynthesis and leaf N resorption of overstory sweetgum (Liquidambar styraciflua L.) trees in the Duke Forest Free Air CO2 Enrichment (FACE) experiment. Sun and shade leaves were subdivided into early leaves (formed in the overwintering bud) and late leaves (formed during the growing season). Overal...

Plants acclimate rapidly to stressful environmental conditions. Increasing atmospheric CO2 levels are predicted to influence tolerance to stresses such as soil salinity but the mechanisms are poorly understood. To resolve this issue, tomato (Solanum lycopersicum) plants were grown under ambient (380 μmol mol(-1)) or high (760 μmol mol(-1)) CO2 in the absence or presence of sodium chloride (100m...

Carbon dioxide (CO2) growth rates are estimated for a period 1959–2004 from atmospheric CO2 measurements at Mauna Loa by the Scripps Institute of Oceanography. Only during a few short periods, 1965–1966, 1972–1973, 1987– 1988 and 1997–1998, in the last 45 yr have growth rates of atmospheric CO2 been of a similar magnitude or higher than that due to the total emission from burning of fossil fuel...

Elevated atmospheric CO2 can influence the structure and function of rhizoplane and rhizosphere microorganisms by altering root growth and the quality and quantity of compounds released into the rhizoplane and rhizosphere via root exudation. In these studies we investigated the transcriptional responses of Bradyrhizobium japonicum cells growing in the rhizoplane of soybean plants exposed to ele...

Forecasting the effects of climate change on nitrogen (N) cycling in pastures requires an understanding of changes in tissue N. We examined the effects of elevated atmospheric CO2 concentration, atmospheric warming and simulated grazing (clipping frequency) on aboveground and belowground tissue N concentrations and C : N ratios of a C3 pasture grass. Phalaris aquatica L. cv. 'Holdfast' was grow...

Atmospheric CO2 concentration has increased from 280 ppm during pre-industrial times to 380 ppm today as a result of human input, and this is thought to be causing enhanced global warming and ocean acidification1. Between 2000 and 2005, global CO2 emissions from burning fossil fuels averaged 26.4 Gt CO2 yr−1, at or above the highest rates predicted by the Intergovernmental Panel on Climate Chan...

Changes in atmospheric CO2 variability during the twenty-first century may provide insight about ecosystem responses to climate change and have implications for the design of carbon monitoring programs. This paper describes changes in the three-dimensional structure of atmospheric CO2 for several representative concentration pathways (RCPs 4.5 and 8.5) using the Community Earth System Model–Bio...