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Ocean Acidification and Jellyfish Abundance
Volume 11, Number 48: 26 November 2008

In a paper recently published in Limnology and Oceanography, Richardson and Gibbons (2008) say there has been a drop of 0.1 pH unit in the global ocean since the start of the Industrial Revolution, and that "such acidification of the ocean may make calcification more difficult for calcareous organisms," resulting in the "opening [of] ecological space for non-calcifying species." In line with this thinking, they report that Attrill et al. (2007) have argued that "jellyfish may take advantage of the vacant niches made available by the negative effects of acidification on calcifying plankton," causing jellyfish to become more abundant; and they note that the latter researchers provided some evidence for this effect in the west-central North Sea over the period 1971-1995. Hence, they undertook a study to see if Attrill et al.'s findings (which were claimed to be the first of their kind) could be replicated on a much larger scale.

Working with data from a larger portion of the North Sea, as well as throughout most of the much vaster Northeast Atlantic Ocean, Richardson and Gibbons used coelenterate (jellyfish) records from the Continuous Plankton Recorder (CPR) and pH data from the International Council for the Exploration of the Sea (ICES) for the period 1946-2003 to explore the possibility of a relationship between jellyfish abundance and acidic ocean conditions. This work revealed that there were, as they describe it, "no significant relationships between jellyfish abundance and acidic conditions in any of the regions investigated."

In harmony with their findings, the two researchers note that "no observed declines in the abundance of calcifiers with lowering pH have yet been reported." In addition, they write that the "larvae of sea urchins form skeletal parts comprising magnesium-bearing calcite, which is 30 times more soluble than calcite without magnesium," and, therefore, that "lower ocean pH should drastically inhibit [our italics] the formation of these soluble calcite precursors." Yet they report "there is no observable negative effect of pH." In fact, they say that echinoderm larvae in the North Sea have actually exhibited "a 10-fold increase [our italics] in recent times," which they say has been "linked predominantly to warming (Kirby et al., 2007)." Likewise, they further note that even in the most recent IPCC report, "there was no empirical evidence reported for the effect of acidification on marine biological systems (Rosenzweig et al., 2007)," in spite of all the concern that has been raised by climate alarmists claiming that such is, or should be, occurring.

In light of this body of real-world evidence, or non-evidence, Richardson and Gibbons conclude (rather generously, we might add) that "the role of pH in structuring zooplankton communities in the North Sea and further afield at present is tenuous."

Sherwood, Keith and Craig Idso

Attrill, M.J., Wright, J. and Edwards, M. 2007. Climate-related increases in jellyfish frequency suggest a more gelatinous future for the North Sea. Limnology and Oceanography 52: 480-485.

Kirby, R.R., Beaugrand, G., Lindley, J.A., Richardson, A.J., Edwards, M. and Reid, P.C. 2007. Climate effects and benthic-pelagic coupling in the North Sea. Marine Ecology Progress Series 330: 31-38.

Richardson, A.J. and Gibbons, M.J. 2008. Are jellyfish increasing in response to ocean acidification? Limnology and Oceanography 53: 2040-2045.

Rosenzweig, C. and others. 2007. Assessment of observed changes and responses in natural and managed systems. In Parry, M.L., Canziani, O.F., Palutikof, J.P., van der Linden, P.J. and Hanson, C.E. (Eds.) Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK, pp. 79-131.