Laboratory experiments suggest that biological particles, such as certain bacteria, fungi and pollen , are known to initiate ice formation at warm sub-zero temperatures (Mohler et al. Biogeosciences vol 4, 1059- 1071, 2007) but the relevance of these particles to atmospheric ice formation was hitherto uncertain.

Two new studies, Pratt et al. Nature Geoscience, vol 2, 398-401 (2009) and Prenni et al. Nature Geoscience, vol 2, 402-405 (2009) conducted with ice collected in situ from clouds over Wyoming and the Amazon respectively, and using modern techniques of mass spectrometry, TEM and EDAX etc., strongly suggests that biogenic material can influence cloud ice formation in the real atmosphere.

Further field studies investigating ice nuclei composition in situ, together with further refinement of methodological techniques, are now needed to to verify the global significance of these recent findings.

If biological particles do prove to be important in cloud-ice interactions, then we need to find a way of incorporating the source, transport and nucleation efficiency of these particles into global climate and smaller-scale models.

http://theresilientearth.com/?q=content/arctic-aerosols-indicate-melting-ice-not-caused-co2

Lebrato, M. and Jones, D.O.B., 2009. Mass deposition event of Pyrosoma atlanticum carcasses off Ivory Coast (West Africa). Limnology and Oceanography, 54, 1197-1209.

Billett, D.S.M., Bett, B.J., Jacobs, C.L., Rouse, I.P. and Wigham, B.D., 2006. Mass deposition of jellyfish in the deep Arabian Sea. Limnology and Oceanography, 51, (5), 2077-2083.

http://news.tradingcharts.com/futures/3/2/124569223.html

Most of the dust in Antarctic ice cores originates in the glacial outwash of Patagonia. Ice cores show that Antarctic warming and a rise in atmospheric carbon dioxide lead Northern Hemipshere warming, potentially indicating a high-latitude Southern Hemisphere trigger (Petit et al. 1999; Broecker et al. 1998).

Sedimentary evidence suggests that during the last glacial period, Patagonian pro-glacial lakes provided an on-off switch for the dust flux to Antarctica. Sugden and co-workers (2009) show that southern Patagonia glaciers also retreated about 21,000 years ago, perhaps as a consequence of decreased precipitation driven by the northward migration of the westerly storm tracks. The southern westerlies reached their northernmost position around 21,000 years ago (Larry et al. 1993).

Could the turning off of the iron-rich dust for Antarctica and the Southern Ocean, which preceded warming in Antarctica by 1000 years, be the critical step in the Termination [of the last ice age]? This finding raises the possibility that reduced iron-stimulated [cyanobacterial] productivity in the Southern Ocean, and hence reduced drawdown of atmospheric carbon dioxide (Martin, 1990) may be an integral component of Termination mechanics.

Ackert, R.P. Nature Geoscience Vol 2 , 244- 245, April 2009.