气候变暖扰乱海洋化学物质循环 据物理学家组织网9月8日报道,英国东英吉利亚大学的一项新研究显示,海洋温度上升将扰乱浮游生物对二氧化碳、氮和磷等化学物质的自然循环。这一研究结果发表在最新一期的《自然—气候变化》杂志上。 在海洋碳循环中,浮游生物发挥着重要作用,通过光合作用将从大气中的二氧化碳去除一半,然后将其储存于深海下的过程,该作用已与大气隔离了几个世纪。该大学环境科学与计算机科学学院的研究人员,用显微镜研究依靠光合作用繁殖和生长的浮游植物,发现微型藻类等浮游植物能自然清除大气中一定的二氧化碳,对于气候控制起到至关重要的作用。这些浮游植物也产生氧气,以及形成渔业食物链的基础,因此,对于粮食安全非常重要。 研究显示,水的温度对维持海洋里浮游生物的生态系统有着直接影响。而海洋变暖将会影响浮游生物,反过来驱动气候变化的恶性循环。首席研究员托马斯·莫克博士说:“以前的研究表明,浮游植物群落通过多样性和生产力的变化应对全球变暖,但我们的研究表明,较高的温度直接影响到海洋的化学循环,而这在之前还没有被证明过。” 作为合作者、埃克塞特大学的研究人员创建了一个全球性的计算机生态系统模型,将全球海洋的温度、从样品中采集的150万浮游生物DNA序列和生物化学的数据整合其中。 莫克博士说:“研究发现,在海洋微型藻类的化学循环中,温度起着至关重要的作用,它对这些反应的影响与养料和阳光差不多,这是以前所不知的。” 他补充说:“在更高的温度下,海洋微型藻类似乎不会像在较低温度下产生许多核糖体。在细胞里核糖体为构建蛋白质‘添砖加瓦’。其富含磷,而如果它们正在减少,相比磷其将产生更高比例的氮,在海洋中增加了对氮的需求。这最终将导致更多的固定大气中氮的蓝藻细菌盛行。”(来源:科技日报 华凌) NATURE CLIMATE CHANGE | LETTER Print Email Share/bookmark The impact of temperature on marine phytoplankton resource allocation and metabolism A. Toseland , S. J. Daines , J. R. Clark , A. Kirkham , J. Strauss , C. Uhlig , T. M. Lenton , K. Valentin , G. A. Pearson , V. Moulton T. Mock Affiliations Contributions Corresponding author Nature Climate Change(2013)doi:10.1038/nclimate1989Received27 March 2013 Accepted29 July 2013 Published online08 September 2013 Article tools Citation Reprints Rights permissions Article metrics Marine phytoplankton are responsible for ~50 % of the CO 2 that is fixed annually worldwide, and contribute massively to other biogeochemical cycles in the oceans 1 . Their contribution depends significantly on the interplay between dynamic environmental conditions and the metabolic responses that underpin resource allocation and hence biogeochemical cycling in the oceans. However, these complex environment–biome interactions have not been studied on a larger scale. Here we use a set of integrative approaches that combine metatranscriptomes, biochemical data, cellular physiology and emergent phytoplankton growth strategies in a global ecosystems model, to show that temperature significantly affects eukaryotic phytoplankton metabolism with consequences for biogeochemical cycling under global warming. In particular, the rate of protein synthesis strongly increases under high temperatures even though the numbers of ribosomes and their associated rRNAs decreases. Thus, at higher temperatures, eukaryotic phytoplankton seem to require a lower density of ribosomes to produce the required amounts of cellular protein. The reduction of phosphate-rich ribosomes 2 in warmer oceans will tend to produce higher organismal nitrogen (N) to phosphate (P) ratios, in turn increasing demand for N with consequences for the marine carbon cycle due to shifts towards N-limitation. Our integrative approach suggests that temperature plays a previously unrecognized, critical role in resource allocation and marine phytoplankton stoichiometry, with implications for the biogeochemical cycles that they drive. At a glance