Exopolymer alteration of physical properties of sea ice and implications for ice habitability and biogeochemistry in a warmer Arctic
Exopolymer alteration of physical properties of sea ice and implications for ice habitability and biogeochemistry in a warmer Arctic
复制标题
DOI：
10.1073/pnas.1100701108
复制
发表时间：
2011-03-01
影响因子：
11.1
通讯作者：
Deming, Jody W.
中科院分区：
文献类型：
--
作者：
Krembs, Christopher;Eicken, Hajo;Deming, Jody W.
北极海冰的物理特性决定了它的宜居性。居住在冰上的生物是否能改变这些特性，目前还很少有人研究。在发现海冰中含有丰富的胶质细胞外聚合物（EPS）之后，我们研究了海藻EPS对冰的微观结构和盐潴持的影响，这些冰是由含有EPS的盐水溶液培养而成的，这些溶液来自海冰硅藻，Melosira arctic。我们还用黄原胶和冷适应细菌Colwellia psyerythraea菌株34H培养的EPS进行了实验。对含有Melosira EPS的人工冰的定量显微分析显示，具有高分形维数的复杂冰孔形态，模仿了富含EPS的沿海海冰的特征，而不含EPS的（对照）冰具有更简单的孔隙几何形状。Melosira EPS的热敏糖蛋白部分解释了复杂的孔隙形态。虽然所有被测试的EPS形式都比对照增加了冰块的盐度（11% -59%），但含有天然Melosira EPS的冰保留了最多的盐。EPS对冰和孔隙微观结构的影响提高了海冰的可居住性、生存能力和初级生产力的潜力，即使它们可能在变暖的气候下改变海冰在海洋表面的持久性和生物地球化学印记。
The physical properties of Arctic sea ice determine its habitability. Whether ice-dwelling organisms can change those properties has rarely been addressed. Following discovery that sea ice contains an abundance of gelatinous extracellular polymeric substances (EPS), we examined the effects of algal EPS on the microstructure and salt retention of ice grown from saline solutions containing EPS from a culture of the sea-ice diatom, Melosira arctica. We also experimented with xanthan gum and with EPS from a culture of the cold-adapted bacterium Colwellia psychrerythraea strain 34H. Quantitative microscopic analyses of the artificial ice containing Melosira EPS revealed convoluted ice-pore morphologies of high fractal dimension, mimicking features found in EPS-rich coastal sea ice, whereas EPS-free (control) ice featured much simpler pore geometries. A heat-sensitive glycoprotein fraction of Melosira EPS accounted for complex pore morphologies. Although all tested forms of EPS increased bulk ice salinity (by 11-59%) above the controls, ice containing native Melosira EPS retained the most salt. EPS effects on ice and pore microstructure improve sea ice habitability, survivability, and potential for increased primary productivity, even as they may alter the persistence and biogeochemical imprint of sea ice on the surface ocean in a warming climate.