How does rising atmospheric CO2 affect marine organisms?

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Fungal Species Affect Plant Biodiversity
Reference
van der Heijden, M.G.A., Boller, T., Wiemken, A. and Sanders, I.R.  1998.  Different arbuscular mycorrhizal fungal species are potential determinants of plant community structure.  Ecology 79: 2082-2091.

What was done
The authors conducted an experiment to determine if arbuscular mycorrhizal fungi (AMF) species composition affects plant community biodiversity.  Specifically, seeds of three plants common to European calcareous grasslands were grown (1) without any AMF species, (2) with one of four morphologically different AMF species, also from the same ecological community, or (3) with equal proportions of all four AMF species.

What was learned
Growth of the three plants differed in response to single AMF species and to the presence of all four AMF species.  Growth of some plants was more dependent upon the presence of AMF species than was that of others, indicating that some plants are dependent upon the presence of specific AMF species, or combinations of different AMF species, for their survival.  Thus, the diversity of AMF species in the soil has the ability to affect plant populations and plant community diversity in various ecosystems.

What it means
As the CO2 content of the air steadily rises, most plants will experience increased carbohydrate production, a portion of which can be exuded into the soil to stimulate the formation and maintenance of symbiotic relationships with AMF.  This increased flux of carbon into the soil will likely increase the activities of such fungi, including those that make soil nutrients, like phosphorus, more readily available to plants.  In addition, with increased carbohydrate exudation into the soil, greater numbers of AMF can be supported in the plant root zone; and this phenomenon should maintain, or possibly increase, plant biodiversity, if the AMF are of different species.  Consequently, the increasing concentration of atmospheric CO2 may well enhance plant biodiversity in earth's many natural ecosystems.


Reviewed 15 January 1999