Background
The authors state that the expansion of species ranges along their cooler boundaries, including range shifts towards both higher latitudes and elevations, appears to be a prominent consequence of global warming; but they say that, to date, "only a limited number of studies have addressed rates of range shifts in marine biotas," citing Sorte et al. (2010). And, therefore, they turn their attention to the world's oceans, focusing their efforts on large symbiont-bearing foraminifera.

What was done
Langer et al., as they describe it, "used historical and newly acquired occurrence records to compute current range shifts of Amphistegina spp." - a large group of symbiont-bearing foraminifera found along the eastern coastline of Africa - comparing them to "analogous range shifts currently observed in the Mediterranean Sea."

What was learned
The work of the five researchers revealed, in their words, that "amphisteginid foraminifera are rapidly progressing southwestward, closely approaching Port Edward (South Africa) at 31°S," moving at rates computed to be between 8 and 2.7 km per year," which rates are "projected to lead to a total southward range expansion of 267 km, or 2.4° latitude, in the year 2100." And they indicate that these findings are "congruent with analogous observations in Mediterranean amphisteginids (Langer et al., 2012) and numerous other marine ectotherms (Yamano et al., 2011; Sorte et al., 2010; Belanger et al., 2012; Luning, 1990; Schmidt-Nielsen, 1990)," which are expanding their range of influence.

What it means
In concluding, Langer et al. indicate that their results "corroborate findings from the fossil record that some larger symbiont-bearing foraminifera cope well with rising water temperatures and are beneficiaries of global climate change [italics added]."

References
Belanger, C.L., Jablonski, D., Roy, K., Berke, S.K., Krug, A.Z. and Valentine, J.W. 2012. Global environmental predictors of benthic marine biogeographic structure. Proceedings of the National Academy of Sciences USA 109: 14,046-14,051.

Langer, M.R., Weinmann, A.E., Lotters, S. and Rodder, D. 2012. "Strangers" in Paradise: Modeling the biogeographic range expansion of the foraminifera Amphistegina in the Mediterranean Sea. Journal of Foraminiferal Research 42: 234-244.

Luning, K. 1990. Seaweeds: Their Environment, Biogeography and Ecophysiology. Wiley-Interscience, New York, New York, USA.

Schmidt-Nielsen, K. 1990. Temperature effects. In: Schmidt-Nielsen, K. (Ed.). Animal Physiology: Adaptation and Environment. Cambridge University Press, New York, New York, USA, pp. 217-239.

Sorte, C.J.B., Williams, S.L. and Carlton, J.T. 2010. Marine range shifts and species introductions: comparative spread rates and community impacts. Global Ecology and Biogeography 19: 303-316.

Yamano, H., Sugihara, K. and Nomura, D. 2011. Rapid poleward range expansion of tropical reef corals in response to rising sea surface temperatures. Geophysical Research Letters 38: 10.1029/2010GL046474.