How does rising atmospheric CO2 affect marine organisms?

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Nematode Life-Span Lengthened by Diet Lacking Coenzyme Q
Larsen, P.L. and Clarke C.F.  2002.  Extension of life-span in Caenorhabditis elegans by a diet lacking coenzyme Q.  Science 295: 120-123.

What was done
The authors fed diets with and without coenzyme Q to wild-type nematodes (Caenorhabditis elegans) and several mutants during the adult phases of their lives, while they recorded the lengths of time they survived.  They then developed a set of biochemical models that seemed to explain their results.

What was learned
In the words of the authors, "withdrawal of coenzyme Q (Q) from the diet of wild-type nematodes extends adult life-span by ~60%."  They also report that the life-spans of the four different mutants they studied were extended by a Q-less diet.  More detailed analyses of their results led them to conclude that the life-span extensions were due to reduced generation and increased scavenging of reactive oxygen species.

What it means
The results and conclusions of this study are similar to those of Melov et al. (2000), who also studied C. elegans and concluded that "oxidative stress is a major determinant of the rate of aging" and that life-span in this species can be lengthened "by augmenting natural antioxidant defenses."  The more extensive review of this phenomenon by Finkel and Holbrook (2000) demonstrates the general principle that oxidative stresses in organisms tend to shorten their life-spans and that "increased resistance to stress should have anti-ageing benefits and lead to enhanced life span."

In this regard, we note that atmospheric CO2 enrichment helps plants withstand the ravages of all sorts of environmental stresses that raise oxidative havoc with them, and that it also stimulates their production of certain health-promoting antioxidants and cancer-fighting substances [see, for example, our Editorial of 28 March 2001, describing the review of this topic by Idso and Idso (2001)], which makes us wonder if the ongoing rise in the air's CO2 content might somehow be promoting increased longevity in both plants and animals.  More research into this intriguing possibility is clearly warranted.

Finkel, T. and Holbrook, N.J.  2000.  Oxidants, oxidative stress and the biology of ageing.  Nature 408: 239-247.

Idso, S.B. and Idso, K.E.  2001.  Effects of atmospheric CO2 enrichment on plant constituents related to animal and human health.  Environmental and Experimental Botany 45: 179-199.

Melov, S., Ravenscroft, J., Malik, S., Gill, M.S., Walker, D.W., Clayton, P.E., Wallace, D.C., Malfroy, B., Doctrow, S.R. and Lithgow, G.J.  2000.  Extension of life-span with superoxide dismutase/catalase mimetics.  Science 289: 1567-1569.

Reviewed 13 March 2002