Abstract The investigation of lipid biomarkers in sediments deposited during the Holocene in the Lagoon of Tunis, located at the southern edge of the Mediterranean Sea, revealed two important hopanoid biomarkers: 2-methylhopaneand 22,29,30 trisnorhop-17(21)-ene. These compounds are considered of special interest because they reveal information about climate conditions during the Late Holocene sediment deposition. These hopanoids, or bacteriohopanepolyols (BHPs), indicate a considerable bacterial contribution to the organic matter preserved in these sediments. The occurrence of 2-methylhopanein substantial amounts indicates that cyanobacteria, Rhodopseudomonas palustris bacteria, and genus Desulfovibriobacteria communities made large contributions to the sediment's organic content. In addition, the presence of these bacteria communities have been interpreted as reliable indicators of hydrologic modifications associated with the development of wetland systems during the Late Holocene. The occurrence of 22,29,30trisnorhop17(21)-ene also suggests a considerable bacterial contribution to the organic matter and indicates an immature diagenesis stage. It also reflects the development of favourable conditions to the preservation and accumulation of organic matter within an anoxic depositional environment.

中文翻译：

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突尼斯湾-地中海南部全新世沉积物中2-甲基hopane和22,29,30Trisnorhop17(21)-ene生物标志物的意义

摘要 对位于地中海南部边缘的突尼斯泻湖全新世沉积物中脂质生物标志物的研究揭示了两种重要的藿烷生物标志物：2-甲基hopane 和 22,29,30 trisnorhop-17(21)-ene . 这些化合物被认为具有特殊意义，因为它们揭示了有关全新世晚期沉积物沉积期间气候条件的信息。这些hopanoids，或bacteriohopanepolyols (BHPs)，表明细菌对这些沉积物中保存的有机物质有相当大的贡献。大量 2-甲基hopanein 的出现表明蓝细菌、沼泽红假单胞菌和脱硫弧菌属群落对沉积物的有机含量做出了很大贡献。此外，这些细菌群落的存在被解释为与全新世晚期湿地系统发展相关的水文变化的可靠指标。22,29,30trisnorhop17(21)-ene 的出现也表明细菌对有机质的贡献相当大，并表明成岩作用不成熟。这也反映了在缺氧沉积环境中有机质保存和积累的有利条件的发展。