How does rising atmospheric CO2 affect marine organisms?

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Volume 2 Number 1:  1 January 1999

Coral Reefs: Doomed by Carbon Dioxide?: A brief review of the many problems currently faced by the world's coral reefs suggests that CO2-induced global warming should come last on a long list of concerns

Journal Reviews
Persistent Millennial-Scale Climate Oscillations: Reconstructions of sea surface temperatures throughout the Pleistocene reveal regular 4 to 4.5C variations during times of ice sheet growth and disintegration, 3C variations during glacial maxima, and 0.5 to 1C variations during warm interglacials.  Climatic warming such as the one being predicted to result from the widespread use of fossil fuels are just not seen, anywhere in the record, suggesting that they probably cannot happen.

Persistent Millennial-Scale Climate Oscillations of the Past Million-Plus Years: Analyses of a North Atlantic sediment core have revealed the existence of persistent millennial-scale climate oscillations similar to those of the last glacial epoch as far back in time as the early Pleistocene.  None of these climate changes are believed to have been produced by atmospheric CO2 variations, suggesting that the even smaller-scale warming of the last hundred years or so has not been caused by any change in the air's CO2 content either.

The Rising Costs of Natural Disasters: Is Global Warming Responsible?: A study of trends in a number of potentially dangerous natural phenomena, along with shifts in national population and wealth density, reveals that the global warming of the past half-century is in no way responsible for the increasing economic losses incurred as a consequence of natural disasters.

Climate Fluctuations on Mount Kenya: A sediment core from a high-altitude lake in East Africa reveals a 3,000-year temperature record that includes a 4C warming over a short 300-year time interval.

Plant Exudate Utilization by Soil Microbes Under Elevated CO2: Perennial ryegrass grown in sand and soil microcosms for 21 days at an atmospheric CO2 concentration of 720 ppm displayed tremendous increases in plant dry weight relative to plants grown at 450 ppm atmospheric CO2.  In soil microcosms, elevated CO2 increased the numbers of culturable bacteria, fungi, and yeast, indicating that increased carbon exudation from the roots of plants grown in elevated CO2 can maintain or increase soil microbial biodiversity.

Fungal Response to Elevated CO2 and Nutrients in Five Grassland Species: Four months of atmospheric CO2 enrichment increased the percent root colonization by arbuscular mycorrhizal fungi in five plant species common to the mediterranean annual grasslands of California, while it only increased colonization by non-mycorrhizal fungi in two species.

Effects of Elevated CO2 on Carbon Allocation of Fungi: The growth of Gutierrezia sarothrae shrubs in elevated CO2 for four months resulted in increased carbon allocation to arbuscular mycorrhizal fungi associated with its roots.  This carbon was invested in different morphological structures depending on soil nitrogen availability.

Effects of Atmospheric CO2 on Soil Biota: Poplar tree cuttings that received atmospheric CO2 enrichment for five months increased soil carbon inputs by increasing root biomass and fine root production.  In turn, this led to increases in the local protozoan population and greater microarthropod associations with fine roots relative to observations made at ambient CO2.  Although elevated CO2 increased mycorrhizal masses only in the presence of high soil nitrogen, the authors believed that this would not affect the ability of fungi to metabolize additional soil carbon inputs resulting from CO2-induced root growth in poplar tree cuttings.

Fungal Species Affect Plant Biodiversity: Total plant biomass varied for three plants common to a European calcareous grassland with different single AMF species or equal proportions of four different AMF species, indicating that AMF species diversity can potentially determine plant community diversity.