生物谷报道：5月8日，一个多国联合小组研究表明大量海藻的存在可以影响附近的天气变化。
研究人员在研究褐藻和大气关系时发现，在阴云密布，海水退潮时是海藻最喜欢的天气，海水的涨落可以保持藻类的湿润。但是在阳光直射时，一旦海水退潮，藻类就会暴露在阳光底下，这时褐藻会释放出一种无机碘。这种碘化物可以中和大气中的臭氧，但是随着碘化物的增多，这些化学物质就变成大气凝结核，云层开始在其周围聚集，为褐藻遮住阳光，从而影响气候，同时为褐藻提供一个更舒适的环境。释放碘化物是海藻在压力状态下的一种自我防御机制，在遭受微生物袭击时，海藻组织也会释放大量碘化物到海水中。（生物谷www.bioon.com）
生物谷推荐原始出处：
PNAS published May 5, 2008, 10.1073/pnas.0709959105
Iodide accumulation provides kelp with an inorganic antioxidant impacting atmospheric chemistry
Frithjof C. Küppera,b,c,d, Lucy J. Carpentere, Gordon B. McFiggansf, Carl J. Palmere,g, Tim J. Waiteh, Eva-Maria Bonebergb,i, Sonja Woitschb, Markus Weillerb, Rafael Abelaj, Daniel Grolimundj, Philippe Potink, Alison Butlerc, George W. Luther, IIIh, Peter M. H. Kroneckb, Wolfram Meyer-Klauckel, and Martin C. Feitersm
aScottish Association for Marine Science, Dunstaffnage Marine Laboratory, Oban, Argyll PA37 1QA, Scotland, United Kingdom; bFachbereich Biologie, Universität Konstanz, D-78457 Konstanz, Germany; cDepartment of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106; eDepartment of Chemistry, University of York, York YO10 5DD, United Kingdom; fSchool of Earth, Atmospheric, and Environmental Sciences, University of Manchester, Manchester M13 9PL, United Kingdom; hCollege of Marine Studies, University of Delaware, Lewes, DE 19958; iBiotechnologie Institut Thurgau, Unterseestrasse 47, CH-8280 Kreuzlingen, Switzerland; jSwiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland; kCentre National de la Recherche Scientifique and Université Pierre et Marie Curie Paris–VI, Station Biologique de Roscoff, Place Georges Teissier, BP 74, F-29682 Roscoff cedex, Bretagne, France; lEuropean Molecular Biology Laboratory, Hamburg Unit, Deutsches Elektronen Synchrotron, Notkestrasse 85, D-22607 Hamburg, Germany; and mDepartment of Organic Chemistry, Institute of Molecules and Materials, Radboud University Nijmegen, 1 Toernooiveld, NL-6525 ED, Nijmegen, The Netherlands
Edited by David M. Karl, University of Hawaii, Honolulu, HI, and approved March 11, 2008 (received for review October 18, 2007)
Abstract
Brown algae of the Laminariales (kelps) are the strongest accumulators of iodine among living organisms. They represent a major pump in the global biogeochemical cycle of iodine and, in particular, the major source of iodocarbons in the coastal atmosphere. Nevertheless, the chemical state and biological significance of accumulated iodine have remained unknown to this date. Using x-ray absorption spectroscopy, we show that the accumulated form is iodide, which readily scavenges a variety of reactive oxygen species (ROS). We propose here that its biological role is that of an inorganic antioxidant, the first to be described in a living system. Upon oxidative stress, iodide is effluxed. On the thallus surface and in the apoplast, iodide detoxifies both aqueous oxidants and ozone, the latter resulting in the release of high levels of molecular iodine and the consequent formation of hygroscopic iodine oxides leading to particles, which are precursors to cloud condensation nuclei. In a complementary set of experiments using a heterologous system, iodide was found to effectively scavenge ROS in human blood cells.
