Are Carotenol-Chlorin Esters Diatom Biomarkers?

胡萝卜素二氯酯是硅藻生物标志物吗？

• 批准号: 9907194
• 负责人: Ralf Goericke
• 金额: $ 16.39万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2002-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9907194&HistoricalAwards=false
• 关键词: Carotenol; Chlorin; Esters; Diatom; Biomarkers

Novel esters of carotenols and chlorins (Carotenol-Chlorin-Esters, CCEs) were recently discovered by the investigator in sediments from the Oman and Peru margin, the Southern California Bight, and Monterey Bay. The chlorins associated with CCEs were pheophorbide a and pyropheophorbide a, degradation products of chlorophyll a (Chl a). Isofucoxanthin-dehydrate and isofucoxanthinol-dehydrate, degradation products of fucoxanthin and a biomarker for diatoms, were the only carotenols associated with CCEs. The PI also found CCEs in water column samples in regions dominated by diatoms and CCEs were found in the fecal pellets of a copepod fed diatoms in the laboratory. It is suggested that CCEs are produced by enzymatically mediated transesterifications in copepods grazing on diatoms. Thus, sedimentary CCEs could be markers for new production derived from diatoms and the organic carbon and nitrogen isotopic signature would reflect that of the diatoms that contributed to the flux of carbon to the sediments. A set of laboratory experiments will further corroborate this hypothesis. Initially experiments will be performed with the copepod, Calanus pacificus, that is present year-round off California. Matched water column and sediment trap samples from the Santa Barbara Basin and Monterey Bay, covering all seasons, will be used to relate the production of CCEs to phytoplankton community structure and other environmental factors.

最近，研究者在阿曼和秘鲁边缘、南加州湾和蒙特利湾的沉积物中发现了新的胡萝卜素醇和氯类酯（胡萝卜素醇-氯类酯，CCEs）。与CCEs相关的氯是叶绿素a （Chl a）的降解产物叶绿素a和叶绿素a。脱水异藻黄素和脱水异藻黄素是岩藻黄素的降解产物和硅藻的生物标志物，是唯一与CCEs相关的胡萝卜素。PI还在以硅藻为主的地区的水柱样本中发现了CCEs，在实验室中，在以硅藻为食的桡足类动物的粪便颗粒中发现了CCEs。这表明，CCEs是由食草硅藻的桡足类通过酶介导的酯交换反应产生的。因此，沉积cce可以作为硅藻新产品的标志，有机碳和氮同位素特征将反映硅藻对碳通量的贡献。一组实验室实验将进一步证实这一假设。最初的实验将以桡足类动物太平洋蛤（Calanus pacificus）进行，这种动物全年都在加州海域生活。来自圣巴巴拉盆地和蒙特利湾的水柱和沉积物捕获器样本覆盖了所有季节，将用于将CCEs的产生与浮游植物群落结构和其他环境因素联系起来。